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  • 251.
    Alfredsson, Jon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Aunet, Snorre
    Department of Informatics, University of Oslo.
    Trade-offs for high yield in 90 nm subthreshold floating-gate circuits by Monte Carlo simulations2008In: Proceedings of IFIP VLSI-SOC Conference 2008: Rhodes, Greece, October 2008, 2008Conference paper (Refereed)
    Abstract [en]

    The work described in this paper is performed toestimate the influence of statistical process variations andtransistor mismatch that occurs in fabrication and affectfloating-gate digital circuits. These effects will affect and reduce“yield” (percentage of fully functional circuits). Monte Carlosimulations have been performed in a 90 nm to estimate theyield for manufactured floating-gate circuits running withsubthreshold power supply. The power supply, floating-gatecharge voltage (VFGP and VFGN) and transistor sizes have beenvaried during the simulations and the yield has been observed.The simulation results shows that by doubling the minimumsize transistors (length and width) the yield can be much betterthan for minimum size version. A yield of 100% can though notbe expected if the power supply is scaled down below 250 mV.

     

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  • 252.
    Alfredsson, Jon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Aunet, Snorre
    Department of Informatics, University of Oslo.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Basic Speed and Power Properties of Digital Floating-gate Circuits Operating in Subthreshold2005In: Proceedings of IFIP VLSI-SOC 2005: International Conference on Very Large Scale Integration, Edith Cowan Univ , 2005, p. 229-232Conference paper (Refereed)
    Abstract [en]

    For digital circuits with ultra-low power consumption,floating-gate circuits have been considered to be a techniquepotentially better than standard static CMOS circuits.By having a DC offset on the floating gates, theeffective threshold voltage of the floating-gate transistoris adjusted and the speed and power performance can bealtered. In this paper the basic performance related propertiessuch as power, delay, power-delay product (PDP),and energy-delay product (EDP) for floating-gate circuitsoperating in subthreshold are investigated. Based on circuitsimulations in a 120nm process technology, it isshown that for the best case, the power can be reducedapproximately by one order of magnitude at the expenseof increased delay, while the PDP is more or less constantin comparison to static CMOS. The EDP can be reducedby two orders of magnitude at the expense of reducednoise margins.

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  • 253.
    Alfredsson, Jon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Aunet, Snorre
    Department of Informatics, University of Oslo.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Small Fan-in Floating-gate Circuits with Application to an Improved Adder Structure2007In: 20TH INTERNATIONAL CONFERENCE ON VLSI DESIGN, PROCEEDINGS - TECHNOLOGY CHALLENGES IN THE NANOELECTRONICS ERA, IEEE conference proceedings, 2007, p. 314-317Conference paper (Refereed)
    Abstract [en]

    For digital circuits with ultra-low power consumption, floating-gate circuits (FGMOS) have been considered to be a potentially better technique than standard static CMOS circuits. One reason for this is because FGMOS only requires a few transistors per gate while it still can have a large fan-in. When power supply is reduced to subthreshold region it will influence the maximum fan-in that is possible to use in designs. In this paper we have investigated how the performance of FGMOS circuits will change in subthreshold region. Simulation in a 120 nm process technology shows that FGMOS will not be working for circuits that have a large fan-in and might not be useable for many designs. At 250 mV power supply it can have a maximum fan-in of 5 and for 150 mV the maximum is 3. FGMOS simulations of an improved full-adder structure with fan-in of 3 is also proposed and compared to a conventional structure with fan-in of 5. It is shown that the improved full-adder with fan-in 3 will have more than 36 times better energy-delay product (EDP)

  • 254.
    Alfredsson, Jon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Capacitance Selection for Digital Floating Gate Circuits Operating in Subthreshold2006In: Proceedings - IEEE International Symposium on Circuits and Systems, IEEE conference proceedings, 2006, p. 4341-4344, article id 1693590Conference paper (Refereed)
    Abstract [en]

    For digital circuits with ultra-low power consumption, floating-gate circuits (FGMOS) have been considered to be a potentially better technique than standard static CMOS circuits. By having a DC offset on the floating gates, the effective threshold voltage of the floating-gate transistor is adjusted and the speed and power performance can be altered. In this paper we have investigated how the floating-gate capacitances can be selected to achieve the best performance in floating-gate circuits operating at subthreshold power supply. Based on circuit simulations in a 120nm process technology, it is shown that the EDP offers a reduction of more than one order of magnitude for FGMOS with capacitance selection in comparison to static CMOS circuits. This paper also deals with the possibilities available for trade-offs between lower power consumption and higher speed to achieve a better performance for FGMOS than for static CMOS. The main cost involved in achieving these performance improvements is reduced noise margins

  • 255.
    Alfredsson, Jon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Influence of Refresh Circuits Connected to Low Power Digital Quasi-Floating gate Designs2006In: 2006 13TH IEEE INTERNATIONAL CONFERENCE ON ELECTRONICS, CIRCUITS AND SYSTEMS, VOLS 1-3, 2006, p. 1296-1299Conference paper (Refereed)
    Abstract [en]

    For digital circuits with ultra-low power consumption, floating-gate circuits (FGMOS) have been considered to be a potentially better technique than standard static CMOS circuits. For each new generation of process technology the thickness of the transistor gate-oxide will be reduced. This will increase charge leakage in FGMOS circuits and it is therefore necessary to introduce techniques to keep the charge in the node. In this paper we investigate how the most commonly used refresh circuits (quasi-and pseudo-floating gate) affect the performance when they are connected to an FGMOS circuit working with subthreshold power supply. The simulations show that refresh circuits equal in size compared to FGMOS will not have much influence on performance while it is reduced up to an order in magnitude when the size increase 8 times. This strong impact from the refresh circuitry also indicates that it might not be an option for future technologies.

  • 256.
    Alfredsson, Jon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Trading Speed and Power for Reduced Substrate Noise from Digital CMOS Circuits2004In: Proceedings of IEEE International Conference on Signals and Electronic Systems, Poznan, Poland: Polish Society for Theoretical and Applied Electrical Engineering , 2004Conference paper (Refereed)
  • 257.
    Alfredsson Kamp, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Media and Communication Science.
    Eriksson, Carl-Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Media and Communication Science.
    Papperstidningen i den digitala tidsåldern: En kvantitativ innehållsanalys i nyhetsvärdering på Aftonbladet2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Purpose and framing of the question: To study how Aftonbladet’s news values and news selection have changed in the last two decades.

    Method and material: Quantitative study in form of a coding scheme covering Aftonbladet’s front pages in the month of march of 1995, 2000, 2005, 2010 and 2015.

    Main result: Both news selection and news value remains in the bigger perspective unchanged, indicating that the newspaper print version is rather unaffected by the change of online journalism. That in turn indicates that the gatekeeper role more or less remains the same for the print version of Aftonbladet.

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  • 258.
    Alfvin, Tiia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Science Education and Mathematics.
    Det laborativa arbetsmaterialet i matematik i lågstadiet (åk1-3) – vad, vem, när, hur & varför?2016Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna studie är att undersöka det laborativa arbetsmaterialets förekomst i matematikundervisningen och ta reda på hur lärare förhåller sig till materialet och användandet av detta i årskurserna 1-3. Undersökningen är huvudsakligen en kvalitativ studie som bygger på 7 enkätfrågor ställda till lärare i lågstadiet. Min undersökning visar att laborativt arbetsmaterial förekommer i matematikundervisningen och används vid genomgångar av lärarna samt vid behov av både elever och lärare. Materialet är både roligt att använda och ett stöd för lärandet. Vissa tyckte dock att det kunde vara jobbigt att plocka fram och städa undan och att eleverna ibland lekte med det. Lärarna gav exempel på kopplingar till läroplanen och de tillfrågade lärarna upplever sig ha tillräcklig kompetens för att kunna bedriva god undervisning för främjandet av elevernas kunskapsutveckling inom ämnet matematik. Det var dock viktigt med ett fungerande erfarenhetsutbyte i arbetslaget samt möjlighet till fortbildning vid behov.

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  • 259.
    Algerstam, Frida
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Science, Design, and Sustainable Development (2023-).
    Lundsten, Julia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Science, Design, and Sustainable Development (2023-).
    Det vita snuset - förpackningens design och förekomst i socialmedia.2023Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    Tobaksfritt snus har lite olika namn, bland annat nikotin påsar och ifolkmun brukar man ofta säga vitt snus. Det vita snuset har under2022 blivit en av de mest sålda snuset och i undersökningar visardet att ungdomars användande ökar. I den här studien undersökervi den grafiska designen på förpackningens lock.I uppsatsen har vi gjort en kvantitativ innehållsanalys för attanalysera viktiga designelement som bygger uppförpackningsdesignen. Vi har samlat in data från 24 stycken olikaprodukter från 12 varumärken, där har vi undersökt färger,typografi och hierarki. Utöver undersökningen av förpackningen såhar vi också gjort en kvalitativ semiotisk bildanalys för att studerahur det vita snuset kommuniceras visuellt på sociala medier, detsociala mediet vi valde i denna studie var Instagram.Under denna studie har vi kommit fram till att vi kunde setydliga designelement som alltid var närvarande i designen ochviktiga informativa delar som bygger upp förpackningsdesignen.När vi studerade vitt snus på Instagram kunde vi även där setydliga mönster på hur varumärken valde att hantera varningstextensom medföljer produkter innehållande nikotin.

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  • 260.
    Alhalbi, Ahmad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Evaluating the Performance of Machine Learning on Weak IoT devices2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    TinyML is a rapidly growing interdisciplinary field in machine learning. They focus on enabling machine learning algorithms on built-in devices (microcontrollers) that work at low power ranges. The purpose of this study is to analyze how well Tiny-ML can solve typical ML tasks. The study had four research questions that were answered by examining different literature studies and implementing test model both on laptop and on built-in devices (Arduino nano 33). The implementation began with creating a machine learning model in the form of a sine function by creating a 3-layer, fully connected neural network that can predict the output of the sine function, in this way the model is used as a regression analysis. The idea is to train the model that accepts values between 0 and 2π and then outputs a value between -1 and 1. Then the model is converted to a Tensorflow Lite to be able to distribute it on the Arduino nano 33. The results showed that TinyML is a good solution for solving ML data, as they managed to transfer the ML algorithm to the microcontroller Arduino nano 33. They could handle and process data without the need for an Internet connection, which allowed developers to program, anywhere and anytime any. TinyML seems to have a bright future and many scientific studies point out that the biggest footprint of machine learning in the future may be through TinyML.

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  • 261.
    Ali, kathem Hassan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering.
    Associated Petroleum Gas management in the south of Iraq2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Iraq is considered as the second largest oil producer in organization of petroleum exporting countries (OPEC) with oil production average of 3.2 MMbbl/day. Iraq has very ambitious plans to increase oil production in the coming few years, which means rapid increase of the associated petroleum gas (APG) which has dissolve form in crude oil and consider as a common by-product with crude oil extraction.

    This study aims to give more understanding about APG management in the south of Iraq and highlight the most important reasons standing behind utilize failure of a huge amount of APG instead of flare it and what the consequences of flare option in the environmental, economic and political perspectives.

    Natural gas featuring as a cleanest fossil fuel with less emission comparing with other types of fossil fuels. In addition, natural gas is considered as an important source for thermal, electrical and mechanical energy and can be used in very wide branches such as transport, industry, electricity and in the housing sector. Furthermore, it is considered as a raw material for petrochemical, fertilizer industries and for the productions of pesticides.

    In this study, APG flaring from economic and environmental perspectives were studied. This study has produced three different scenarios for the future gas production. Three different scenarios were studied (business as usual (BAU), new processing facilities (NPF) and gas to grid (GTG)). BAU scenario depends on rehabilitate the entire infrastructures which are old, unsufficient and it is platform capacity is very small to capture and process a huge amount of APG which expected to be produced in the coming years. NPF means build new capturing and processing facilities to treat the total expected amount of APG and the GTG scenario depend on the same assumptions of the second scenario but, all the produced dry gas will destined to the power plant to produce electricity.

    Most promising results (economic and environment results) gained by adapting GTG scenario. These results, however, might explain and justify the economic investment that should be used in the Iraqi gas industry will give more revenue, improve Iraqis people life conditions and reduce the global environmental degradation.

    As a result of that the imported gas, electricity and natural gas liquids (NGL) will be stopped after three to five years. So it is recommended that the produced dry gas should utilize in the power plant as a feedstock instead of crude oil and diesel and after the increasing of provide dry gas can Iraq stop import gas and electricity as well.

    More involved by adopting gas to grid scenario because the produced dry gas used as feedstock in the power generations to cover the domestic and industry demand for electricity. More investment needs to apply this scenario but also more benefit will be gain due to replacing oil and diesel which are currently used in the power plants by using natural gas.

    Iraq has to take rapid steps toward changing all the existing fuel fire generators to cover the shortage of electricity supply and guaranteed the domestic and the industrial sectors of stable providing of electricity. Iraq is facing a real problem at the moment because of the burning of Iraqi gas, which causes to accumulate of 20 million tons per year of carbon dioxide emissions, the equivalent of three million tailpipe emissions car.

    Accompanied with the increasing in crude oil production during the past few years an increase in the production of APG, which means an increase in the quantities of burned gas and that needs to evolution of energy installations of gas collection and treatment in the same period. In addition, increase the quantities of liquid petroleum gas and light naphtha for domestic demand, will be an urgent need for the establishment of appropriate facilities for the storage and export in the south harbors to export the surplus for the local need.

    The implementation of these scenarios beginning in 2015 requires speeding up the construction of the assembly plants, pressure, treatment and the related infrastructures at the level of the oil fields production. The construction of the necessary pipelines infrastructure needs to connect the centers of demand treatment plants, power plants and the oil wells. It is also required to raise the capacity of the gas filling facilities near centers of domestic consumption.

    Preparation of technical plans for the gas system, gas industries, electricity generation and all the investment possibilities will be very important and it should be ready by 2015 to exploit the total gas production in Iraq and its treatment, so that it becomes available to transfer it to the local and international markets. At that point, gas flaring may reach to the lowest level, and then will meet all the requirements of the local gas demand, local electricity demand and contributing with international efforts to protect the global environment.

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  • 262.
    Ali M., Ahmed
    et al.
    University of Duisburg-Essen.
    Moulik, Bedatri
    Amity University.
    Beganovic, Nejra
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Söffker, Dirk
    University of Duisburg-Essen.
    A State-of-Health-Oriented Power Management Strategy for Multi-Source Electric Vehicles Considering Situation-Based Optimized Solutions in Real-Time2019In: Proceedings of the Annual Conference of the PHM Society 11 (1), Scottsdale, Arizona, USA: PHM Society , 2019, Vol. 11, p. 1-10, article id 783Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel situation-based power and battery health management strategy for fuel cell vehicles. In such hybrid powertrains, the synergy role of batteries is essential to minimize overall power consumption and maintain higher electrical efficiency of the fuel cell. On the other hand, lifetime degradation of the battery is associated with the recurrent charging / discharging cycles. The proposed power management strategy addresses the trade-off between these contradictory objectives. Vehicle states in each situation are defined in terms of driver-related identification parameters (power demand and speed) corporately with powertrain related ones (on-board battery's state of charge). Optimal power handling solution for each situation is searched offline considering different optimization criteria: range extension, lifetime maximization, or power consumption minimization. A weighted fusion of these optimized solutions can be implemented online based on desired driving strategy, leading to situation-based optimized solution. This contribution aims to provide flexible power handling options meeting performance requirements (energy efficiency and driveability) without scarifying battery life. Simulation tests using different driving cycles are conducted for evaluation purpose.

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  • 263.
    Ali, Majid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Improving the Adaptive Context Views and Evaluate Real-Time Performance2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The versatility and dimension of smart phone applications is   increasing at magnificent rate and getting more and more advanced in a level that could solve complicated real time tasks. One of the important factors for such advancement has been the powerful sensors embedded on a Smartphone devices and sensory networks. Moreover, Context and Context-awareness would have remained a myth without the advent of sensors. The objective of this thesis has been to contribute to the research work carried out under the MediaSense project. Accordingly, the ultimate purpose of the thesis has been to evaluate and study the feasibility of the adaptive context view proposed in MediaSense Platform. In precise words, the thesis has done three core tasks. Firstly, the theoretical presentation of related works and the significance of the research question have been discussed through various social applications. Secondly, a proof-of-concept application has been developed to simulate what has been proposed in the research work. Finally, Android application has been designed and implemented in order to evaluate and study the techniques presented in a practical scenario. Moreover, in the android application known as SundsvallBIGBuddies, we have used the extensions designed for the existing MediaSense platform. The impact of using Android app relaying on a continuous stream of context data has been presented using graphs and tables.  In order to study the impact we used smart phone and tablets from Samsung.

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    Improving the Adaptive Context Views and Evaluate Real-Time Performance Sundsvall BIGBuddies App
  • 264.
    Ali, S.
    et al.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    Orban, I.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    Mahmood, S.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    Altun, Z.
    Marmara Univ, Dept Phys, TR-81040 Istanbul, Turkey.
    Glans, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Schuch, R.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    ELECTRON-ION RECOMBINATION RATE COEFFICIENTS FOR C II FORMING C I2012In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 753, no 2, p. Art. no. 132-Article in journal (Refereed)
    Abstract [en]

    We have determined absolute dielectronic recombination rate coefficients for C II, using the CRYRING heavy-ions storage ring. The resonances due to 2s-2p (Delta n= 0) core excitations are detected in the center-of-mass energy range of 0-15 eV. The experimental results are compared with intermediate coupling AUTOSTRUCTURE calculations. Plasma rate coefficients are obtained from the DR spectrum by convoluting it with a Maxwell-Boltzmann energy distribution for temperatures in the range of 10(3)-10(6) K. The derived temperature-dependent plasma recombination rate coefficients are presented graphically and parameterized by using a fit formula for convenient use in plasma modeling codes. The experimental rate coefficients are also compared with the theoretical data available in literature. In the temperature range of 10(3)-2 x 10(4) K, our experimental results show that previous calculations severely underestimate the plasma rate coefficients and also our AUTOSTRUCTURE calculation does not reproduce the experimental plasma rate coefficients well. Above 2x10(4) K, the agreement between the experimental and theoretical rate coefficients is much better, and the deviations are smaller than the estimated uncertainties.

  • 265.
    Ali, Tara
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Essén, Sofia A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Lundström, Ulla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Liquid extraction of low molecular mass organic acids and hydroxamate siderophores from boreal forest soil2011In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 43, no 12, p. 2417-2422Article in journal (Refereed)
    Abstract [en]

    Low molecular mass organic acids (LMMOAs) and hydroxamate siderophores (HS) are molecules secreted by microbes and have previously been found in soil solution and in cultures. Mycorrhizal fungi are suggested to be involved in the nutrient uptake processes of trees and weathering of minerals. In this study soil samples taken from the O and E horizons of a podzol were extracted with 10 mM potassium phosphate buffer at pH 7.2. Variable parameters included addition of methanol to the extraction buffer and the use of ultrasonication or rotary shaking during extraction. LMMOAs and HS content of the soil extracts were determined. Analysis of soil extracts were carried out by liquid chromatography mass spectrometry (LC-MS) and the extraction results compared to results for soil solution samples obtained by centrifugation of the soils sampled. The extraction yields were significantly increased by addition of methanol to the extraction buffer, especially for the O horizon samples. Rotary shaking of the samples for 90 min gave slightly higher yields than ultrasonication for 15 min but the reduction in extraction time makes ultrasonication an attractive option. Of the HSs determined, ferricrocin was found in all samples. Optimal extraction conditions showed citric acid and isocitric acid to be the most abundant organic acids in the O and E horizons, respectively.

  • 266.
    Alic, Emin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media. Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Publiceringsfunktion för obemannade tjänster avseende användbarhet2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 267.
    Alienus, Annica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Computer and System Science.
    Varför korrigerar du dig själv?: Vem, vad, hur och varför – ett kvalitativt perspektiv av manipulering av selfies på sociala medier2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For most people social media has become a natural part of everyday life and there are probably few who have missed the rising popularity of selfies, but perhaps the rising popularity of photo manipulation is less obvious. Although studies have shown that selfies can have positive effects, there are still a general agreement that the development is concerning, and since the selfie seems to be here to stay, it is important to gain more knowledge about the phenomenon. The study used a mixed method to describe who photo manipulates selfies, what in the selfie that gets corrected, how the correction is performed and why someone chooses to photo manipulate selfies on social media. Using a web-based questionnaire and semi-structured interviews, quantitative data could be collected which were analysed using descriptive statistics, additionally the qualitative data were interpreted using a thematic analysis.

    The results showed that younger women photo manipulated selfies more often than younger men, but the difference levelled out with age, that the time spent on social media did not lead to a higher frequency of photo manipulation and that the most frequently used photo manipulation was filters and photo effects. In addition, the driving forces of impression control, the selfie-self, digital culture, and self-encouragement could be identified, and affected what was corrected, how the correction was performed and the frequents of photo manipulation on selfies. The result showed that photo manipulation of selfies on social media can have positive effects which can help to nuance the discussion about digital editing of selfies.

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  • 268.
    Alimadadi, Majid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Foam-formed Fiber Networks: Manufacturing, Characterization, and Numerical Modeling: With a Note on the Orientation Behavior of Rod-like Particles in Newtonian Fluids2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fiber networks are ubiquitous and are seen in both industrial materials (paper and nonwovens) and biological materials (plant cells and animal tissues). Nature intricately manipulates these network structures by varying their density, aggregation, and fiber orientation to create a variety of functionalities.

    In conventional papermaking, fibrous materials are dispersed in water to form a sheet of a highly oriented two-dimensional (2D) network. In such a structure, the in-plane mechanical and transport properties are very different from those in the out-of-plane direction. A three-dimensional (3D) network, however, may offer unique properties not seen in conventional paper products.

    Foam, i.e., a dispersed system of gas and liquid, is widely used as the suspending medium in different industries. Recently, foam forming was studied extensively to develop the understanding of foam-fiber interactions in order to find potential applications of this technology in papermaking.

    In this thesis, a method for producing low-density, 3D fiber networks by utilizing foam forming is investigated and the structures and mechanical properties of such networks are studied. Micro-computed tomography is used to capture the 3D structure of the network and subsequently to reproduce artificial networks. The finite element method is utilized to model the compression behavior of both the reproduced physical network and the artificial networks in order to understand how the geometry and constitutive elements of the foam-formed network affect its bulk mechanical properties. Additionally, a method was studied in order to quantify the orientation behavior of particles in a laminar Newtonian flow based on the key parameters of the flow which control the orientation.

    The resulting foam-formed structures were extremely bulky. Yet despite this high bulk, the fiber networks retained good structural integrity. The compression behavior in the thickness direction was characterized by extreme compressibility and high strain recovery after compression. The results from the modeling showed that the finite-deformation mechanical response of the fiber network in compression was satisfactorily captured by the simulation. However, the artificial network shows higher stiffness than the simulated physical network and the experiment. This discrepancy in stiffness was attributed to macroscopic structural non-uniformities in the physical network, which result in increased local compliance. It was also found that the friction between the fibers, as well as the fiber curvature, had a negligible impact on the compression response of the fiber network, while defects (in the form of kinks) had an effect on the response in the last stages of compression. The study of the orientation behavior of particles at different flow velocities, particle sizes, and channel geometries suggests that it might be possible to utilize the flow shear rate as a means to quantify the orientation behavior.

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  • 269.
    Alimadadi, Majid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lindström, Stefan B.
    Division of Solid Mechanics, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Kulachenko, Artem
    Department of Solid Mechanics, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Role of microstructures in the compression response of three-dimensional foam-formed wood fiber networks2018In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 14, no 44, p. 8945-8955, article id C7SM02561KArticle in journal (Refereed)
    Abstract [en]

    High-porosity, three-dimensional wood fiber networks made by foam forming present experimentally accessible instances of hierarchically structured, athermal fiber networks. We investigate the large deformation compression behavior of these networks using fiber-resolved finite element analyses to elucidate the role of microstructures in the mechanical response to compression. Three-dimensional network structures are acquired using micro-computed tomography and subsequent skeletonization into a Euclidean graph representation. By using a fitting procedure to the geometrical graph data, we are able to identify nine independent statistical parameters needed for the regeneration of artificial networks with the observed statistics. The compression response of these artificially generated networks and the physical network is then investigated using implicit finite element analysis. A direct comparison of the simulation results from the reconstructed and artificial network reveals remarkable differences already in the elastic region. These can neither be fully explained by density scaling, the size effect nor the boundary conditions. The only factor which provides the consistent explanation of the observed difference is the density and fiber orientation nonuniformities; these contribute to strain-localization so that the network becomes more compliant than expected for statistically uniform microstructures. We also demonstrate that the experimentally manifested strain-stiffening of such networks is due to development of new inter-fiber contacts during compression.

  • 270.
    Alimadadi, Majid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Uesaka, Tetsu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    3D-oriented fiber networks made by foam forming2016In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, ISSN 1572-882X, Vol. 23, no 1, p. 661-671Article in journal (Refereed)
    Abstract [en]

    In industrial applications, such as paper and nonwovens, cellulose fibers are used in the form of a network where the fibers are oriented more or less in the sheet-plane direction. However, in many biological systems, fibers are instead oriented in a three-dimensional (3D) space, creating a wide variety of functionalities. In this study we created a 3D-oriented fiber network on the laboratory scale and have identified some unique features of its structure and mechanical properties. The 3D fiber network sheets were prepared by using foam-forming as well as modifying consolidation and drying procedures. The fiber orientation and tensile/compression behavior were determined. The resulting sheets were extremely bulky (above 190 cm3/g) and had extremely low stiffness (or high softness) compared to the reference handsheets. Despite this high bulk, the sheets retained good structural integrity. We found that a 3D-oriented fiber network requires much less fiber-fiber contact to create a connected (“percolated”) network than a two-dimensionally oriented network. The compression behavior in the thickness direction was also unique, characterized by extreme compressibility because of its extreme bulk and a long initial increase in the compression load as well as high strain recovery after compression because of its fiber reorientation during compression.

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  • 271.
    Alimadadi, Majid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Uesaka, Tetsu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Exploring One-more Dimension of Paper: Properties of 3D-Orieneted Fiber Network2014In: Progress in Paper Physics Proceedings 2014, 2014Conference paper (Other academic)
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  • 272.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Eco-friendly and Catalytic Surface Engineering of Cellulose and Nanocellulose2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The non-stop use of petroleum-based materials such as plastics can generate significant environmental problems, including pollution of the oceans and increased CO2 levels, and cause diseases like cancer due to the starting monomers. Consequently, increased use of sustainable and non-toxic polymers and monomers is required to address these issues. Cellulose, generously supplied by Mother Nature, is the most abundant biopolymer on Earth. Nanocellulose is a sustainable polymer extracted from the cellulose inwood or produced by bacteria and algae. This biodegradable nanomaterialhas recently been receiving intense research attention, since it has great potential for use in a broad range of industrial and biomedical applications. However, it has limitations such as moisture sensitivity and incompatibility with hydrophobic materials due to its hydrophilic nature. Chemical modification is necessary for it to fulfill the requirements for applications that require high moisture resistance and water repellency. Unfortunately, several of the existing methods involve harsh and toxic conditions or reagents. In this thesis, together with my co-workers, I have employed the toolbox of organocatalysis for accomplishing eco-friendly and innovative surface modification of cellulose and nanocellulose. The organocatalysts we usedmost in our research are the naturally abundant and industrially relevantorganic acids tartaric acid and citric acid.

    Direct catalytic esterification of cellulose nanocrystal (CNC) with thioglycolicacid was performed either in suspension or on solid surfaces such as films and foams. We found that the reaction was accelerated by tartaric acid but could also be autocatalytic with respect to the thioglycolic acid under certain conditions. The synthesized CNC-SH was further exploited as a heterogeneous reducing agent as well as a handle for further nanocellulose modifications. This was demonstrated by using CNC-SH as a heterogenous reducing agent of Cu(II) to Cu(I), which is essential for allowing the Cu to actas a catalyst for 2,3-dipolar cycloaddition reactions between azides andalkynes. We also showed that the thia-modified CNC could undergo further functionalizing via thiol-ene click chemistry reactions, for example, we attached fluorescent compounds such as TAMRA and quinidine.

    Herein we provide a fluorine-free method to prepare superhydrophobic CNC film with excellent water-resistance properties by combining self-assemblyand organocatalysis. Self-assembly of CNC via vacuum filtration resulted in xa film with a specific roughness at the microscale. Next, the catalytic silylation with a variety of alkoxysilanes in the presence of natural organic acids such as tartaric acid and citric acid was performed. The successful implementation of our method resulted in a super-hydrophobic CNC film (water contact angleover 150°) with excellent water-resistance. Thus, the combination of the selfassembly of a rough surface with catalytic surface modification resulted in a phenomenon like the “lotus effect” as exhibited by the leaves of the lotus flower. An investigation of the oxygen permeability of the octadecyltrimethoxysilane-modified CNC film revealed that it significantly decreased at high relative humidity compared with unmodified CNC films.

    In this thesis, the fabrication of hydrophobic and functionalized MTM/CNF nanocomposites using organocatalytic surface modification with a large variety of alkoxysilanes is also performed. The surface modifications are mildand the mechanical strength of the Nacre-mimetic nanocomposites is preserved. Elemental mapping analysis revealed that the silane modification occurred predominantly on the surface.

    A combination of organocatalyst and biopolyelectrolyte complex was appliedfor surface engineering of chemi-thermomechanical pulp (CTMP) and bleached sulfite pulp (BSP). The reaction was performed using a synergistic combination of an organocatalyst with a polyelectrolyte (PE) complex. Using this method, the strength properties of CTMP and BSP sheets were significantly increased (up to 100% in Z-strength for CTMP). Further investigations of the distribution of the PE complex were then performed using TAMRA and quinidine labeling and confocal laser scanningmicroscopy. This revealed that an even distribution of the cationic starch component of the PE complex had occurred within the CTMP-based paper sheets, which follows its lignin distribution pattern.

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  • 273.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Goclik, Lisa
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Tai, Cheuk-Wai
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Direct Organocatalytic Thioglycolic Acid Esterification of Cellulose Nanocrystals: A simple entry to click chemistry on the surface of nanocellulose2022In: Carbohydrate Polymer Technologies and Applications, ISSN 2666-8939, Vol. 3, article id 100205Article in journal (Refereed)
    Abstract [en]

    The mild and simple direct organocatalytic esterification of cellulose nanocrystals (CNC) and nanocellulose-based materials (e.g. foams and films) with thioglycolic acid (TGA) is disclosed. The transformation gives the corresponding thiol group (-SH) functionalized crystalline nanocellulose (CNC-SH) using simple, naturally occurring, and non-toxic organic acids (e.g. tartaric acid) as catalysts. We also discovered that the direct esterification of cellulose with TGA is autocatalytic (i.e. the TGA is catalyzing its own esterification). The introduction of the -SH functionality at the nanocellulose surface opens up for further selective applications. This was demonstrated by attaching organic catalysts and fluorescent molecules, which are useful as sensors, to the CNC-SH surface by thiol-ene click chemistry. Another application is to use the CNC-SH-based foam as a heterogeneous biomimetic reducing agent, which is stable during multiple recycles, for the copper-catalyzed alkyne-azide 1,3-dipolar cycloaddition (“click” reaction).

  • 274.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Persson, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Marksted, Kajsa
    Hilden, Lars
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Improving the mechanical properties of CTMP fibers by combining synergistic organocatalytic/polyelectrolyte complex surface engineering with sulfite pretreatment2022In: Proceedings of the International Mechanical Pulping Conference, 2022, p. 149-Conference paper (Other academic)
    Abstract [en]

    Fabrication of paper-based packaging materials is increasing and the challenge is developing a sustainable process to manufacture the materials that can compete with plastics. Employing stronger fiber in production of fiber-based materials improves the efficiency of fabrication process by using a reduced amount of biomass. Cationic starch is a well-known polysaccharide that has been introduced to paper and paperboard fibers to improve the mechanical properties of lignocellulosic fibers. The polyelectrolyte (PE) multilayer method has been popularized as a new and interesting technique to enhance the adsorption of cationic starch on the fiber for improving the strength properties of chemi-thermomechanical pulp (CTMP), chemical and kraft pulps. We have shown in our previous work that the synergistic combination of organocatalysis and PE complexes improved the mechanical properties of CTMP and TMP. In this work, we chose to expand this concept by integrating it with low-dose sulfite pretreatment of wood chips in preparation of CTMP. Thus, CTMP produced by initial sulfite pre-treatment was next surface engineered by synergistic combination of organocatalysis and PE complexes using organic acids as catalysts. The CTMP pulps, which contains 0.1-0.24 wt.% sulfur, produced by our novel pulp-engineering strategy shows a dramatic strength increase (Z- strength: up to 100 %) as compared to no surface engineering. While only sulfite pre-treatment and PE-complex surface engineering were able to improve the strength properties, it was only when the organic catalysts was present that the highest strength improvements were reached. Thus, a clear synergistic effect of the catalyst was observed.

  • 275.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Medina, Lilian
    KTH.
    Deiana, Luca
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Berglund, Lars A.
    KTH.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Mild and Versatile Functionalization of Nacre-Mimetic Cellulose Nanofibrils/Clay Nanocomposites by Organocatalytic Surface Engineering2020In: ACS Omega, E-ISSN 2470-1343, Vol. 5, no 31, p. 19363-19370Article in journal (Refereed)
    Abstract [en]

    Development of surface-engineering strategies, which are facile, versatile, and mild, are highly desirable in tailor-made functionalization of high-performance bioinspired nanocomposites. We herein disclose for the first time a general organocatalytic strategy for the functionalization and hydrophobization of nacre-mimetic nanocomposites, which includes vide supra key aspects of surface engineering. The merging of metal-free catalysis and the design of nacre-mimetic nanocomposite materials were demonstrated by the organocatalytic surface engineering of cellulose nanofibrils/clay nanocomposites providing the corresponding bioinspired nanocomposites with good mechanical properties, hydrophobicity, and useful thia-, amino, and olefinic functionalities. 

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  • 276.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Cellulosic Materials: Sustainable Surface Engineering of Lignocellulose and Cellulose by Synergistic Combination of Metal-Free Catalysis and Polyelectrolyte Complexes2019In: Global Challenges, E-ISSN 2056-6646, Vol. 3, no 7, article id 1970071Article in journal (Refereed)
    Abstract [en]

    In article number 1900018 by Armando Cordova and co‐workers, the novel combination of metal‐free catalysis and renewable polyelectrolyte complexes leads to synergistic surface engineering of lignocellulose and cellulose fibers derived from wood. This sustainable strategy allows for improvement and introduction of important properties such as strength (up to 100% in Z‐strength), water resistance, and fluorescence to the renewable fibers and cellulosic materials under eco‐friendly conditions.

  • 277.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sustainable Surface Engineering of Lignocellulose and Cellulose by Synergistic Combination of Metal‐Free Catalysis and Polyelectrolyte Complexes2019In: Global Challenges, E-ISSN 2056-6646, Vol. 3, article id 1900018Article in journal (Refereed)
    Abstract [en]

    A sustainable strategy for synergistic surface engineering of lignocellulose and cellulose fibers derived from wood by synergistic combination of metal‐free catalysis and renewable polyelectrolyte (PE) complexes is disclosed. The strategy allows for improvement and introduction of important properties such as strength, water resistance, and fluorescence to the renewable fibers and cellulosic materials. For example, the “green” surface engineering significantly increases the strength properties (up to 100% in Z‐strength) of chemi‐thermomechanical pulp (CTMP) and bleached sulphite pulp (BSP)‐derived sheets. Next, performing an organocatalytic silylation with a nontoxic organic acid makes the corresponding lignocellulose and cellulose sheets hydrophobic. A selective color modification of polysaccharides is developed by combining metal‐free catalysis and thiol‐ene click chemistry. Next, fluorescent PE complexes based on cationic starch (CS) and carboxymethylcellulose (CMC) are prepared and used for modification of CTMP or BSP in the presence of a metal‐free catalyst. Laser‐scanning confocal microscopy reveals that the PE‐strength additive is evenly distributed on the CTMP and heterogeneously on the BSP. The fluorescent CS distribution on the CTMP follows the lignin distribution of the lignocellulosic fibers.

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  • 278.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Scalable Improvement of the Strength Properties of Chemimechanical Pulp Fibers by Eco-Friendly Catalysis2018In: IMPC 2018, Trondheim, Norway, 2018Conference paper (Refereed)
    Abstract [en]

    The sustainable improvement of the strength properties of chemimechanical pulp by eco-friendlycatalysis is disclosed. Significant research activities have been performed on the use of cationic starchand polyelectrolyte complexes for improving the strength properties of cellulose-based materials. Herewe apply an eco-friendly strategy based on catalysis for significantly improving the strength propertiesof sheets made from chemimechanical pulp (CTMP) and bleeched sulphite pulp (BSP) using sustainablepolyelectrolyte complexes as the strength additives and organocatalysis. This surface engineeringstrategy significantly increased the strength properties of the assembled sheets (up to 100% in the caseof Z-strength). We also developed a catalytic selective colour marking of the cationic potato starch (CS)and carboxymethylcellulose (CMC) in order to elucidated how the specific strength additives aredistributed on the sheets. It revealed that the strength additives were more evenly distributed on thesheets made from CTMP as compared to BSP sheets. This is most likely attributed to the presence oflignin in the former lignocellulosic material. It also contributes to the increase in strength (up to 100%,Z-strength) for the CTMP derived sheets. The selective colour marking method also revealed that morestrength additives had been bound to the pulps in the presence of the catalyst.

  • 279.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Mathematics, and Science Education (2023-).
    Sanhueza, Italo
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Mathematics, and Science Education (2023-).
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Mathematics, and Science Education (2023-).
    Design and fabrication of superhydrophobic cellulose nanocrystal films by combination of self-assembly and organocatalysis2023In: Scientific Reports, E-ISSN 2045-2322, Vol. 13, no 1, article id 3157Article in journal (Refereed)
    Abstract [en]

    Cellulose nanocrystals, which have unique properties of high aspect ratio, high surface area, high mechanical strength, and a liquid crystalline nature, constitute a renewable nanomaterial with great potential for several uses (e.g., composites, films and barriers). However, their intrinsic hydrophilicity results in materials that are moisture sensitive and exhibit poor water stability. This limits their use and competitiveness as a sustainable alternative against fossil-based materials/plastics in packaging, food storage, construction and materials application, which cause contamination in our oceans and environment. To make cellulose nanocrystal films superhydrophobic, toxic chemicals such as fluorocarbons are typically attached to their surfaces. Hence, there is a pressing need for environmentally friendly alternatives for their modification and acquiring this important surface property. Herein, we describe the novel creation of superhydrophobic, fluorocarbon-free and transparent cellulose nanocrystal films with functional groups by a bioinspired combination of self-assembly and organocatalytic surface modification at the nanoscale using food approved organic acid catalysts. The resulting film-surface is superhydrophobic (water contact angle > 150°) and has self-cleaning properties (the lotus effect). In addition, the superhydrophobic cellulose nanocrystal films have excellent water stability and significantly decreased oxygen permeability at high relative humidity with oxygen transmission rates better than those of commonly used plastics. 

  • 280. Alioua, A.
    et al.
    Hamiroune, R.
    Amiri, O.
    Khelifi, M.
    Senouci, S. -M
    Gidlund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Fakhrul Abedin, Sarder
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Incentive mechanism for competitive edge caching in 5G-enabled Internet of things2022In: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 213, article id 109096Article in journal (Refereed)
    Abstract [en]

    The fifth generation (5G) of cellular networks provides the enabling environment for the Internet of Things (IoT) applications. Hence, the vast proliferation of 5G-enabled IoT devices and services led to an overwhelming growth of data traffic that could saturate the core network's backhaul links. Nowadays, caching is an unavoidable technique to solve this issue, whereby popular contents are stored on edge nodes near to end-users. There exist several initiatives to motivate caching actors for improving the caching process, but not designed for the real-world competitive caching market. In this work, we propose an incentive caching strategy in a 5G-enabled IoT network by considering a completely competitive caching scenario with multiple 5G mobile network operators (MNOs) and multiple content providers (CPs). The MNOs manage a set of edge caches on their base stations and they are competing to fill these caching resources, while the CPs detain a set of popular contents and are in conflict to rent the MNOs’ caches. Each MNO aims to maximize its monetary profit and offload its backhaul links, as each CP aims to improve the quality of experience (QoE) of its end-users. Then, we formulate a multi-leader multi-follower Stackelberg game to model the interaction between MNOs and CPs and define the different players’ utilities. Subsequently, we propose an iterative algorithm based on the convex optimization method to investigate the Stackelberg equilibrium. Finally, the numerical results of the different experimentations demonstrate that our game-based incentive strategy can significantly alleviate the backhaul links while improving the user QoE. 

  • 281.
    Alishah, Rasoul Shalchi
    et al.
    Univ Tabriz, Tabriz, Iran.
    Hasani, Mir Yahya
    Islamic Azad Univ Tabriz, Tabriz, Iran.
    Hosseini, Seyed Hossein
    Univ Tabriz, Tabriz, Iran.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Babalou, Milad
    Univ Tabriz, Tabriz, Iran.
    Analysis and Design of a New Extendable Sepic Converter with High Voltage Gain and Reduced Components for Photovoltaic Applications2019In: 2019 10th International Power Electronics, Drive Systems and Technologies Conference (PEDSTC), IEEE, 2019, p. 492-497, article id 8697249Conference paper (Refereed)
    Abstract [en]

    This paper presents a high step-up DC-DC converter which is appropriate for Photovoltaic systems. This topology has been combined from an extended switched-capacitor and a common SEPIC converter. Low components and high-voltage-gain are the main benefits of the introduced topology. Low rate current ripple, easy control and continuous input current are other advantages of the presented structure. Integrating the switched-capacitor with the SEPIC converter leads to increase the output voltage with variable conversion ratio which can be used for a wide range of loads. The switched-capacitor converter provides a constant dc output voltage while the SEPIC converter extracts maximum power of PV panels because it operates under control of duty cycle. Continuous input current is highly suitable for PV applications. The operating principles and steady-state analysis of the suggested topology are discussed in detail. In order to assess the effectiveness of the presented topology, it has been simulated on PSCAD/EMTDC software.

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  • 282. Alison, M Lee-Manion
    et al.
    Price, Ruth K
    Strain, J J
    Dimberg, Lena H
    Sunnerheim, Kerstin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Welch, Robert W
    In Vitro Antioxidant Activity and Antigenotoxic Effects of Avenanthramides and Related Compounds2009In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 57, no 22, p. 10619-10624Article in journal (Refereed)
    Abstract [en]

    Avenanthramides are substituted N-cinnamoylanthranilic acids, with hydroxycinnamic acid and anthranilic acid moieties. These alkaloid phenols, which are unique to oats, may confer health benefits via antioxidant or other mechanisms. Synthetic avenanthramides, hydroxycinnamic acids, Tranilast, and ascorbic acid were evaluated for antioxidant activity using two assays, DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant potential), and for antigenotoxicity using the Comet assay with stressed human adenocarcinoma colon cells. Of all the compounds tested, N-(3′,4′-dihydroxy-(E)-cinnamoyl)-5-hydroxyanthranilic acid (2c), an abundant oat avenanthramide, generally had the highest activity in all three assays. The drug Tranilast showed antigenotoxic effects, but not antioxidant activity, suggesting that antigenotoxicity is not dependent on antioxidant effects. Overall, results show that avenanthramides exert antioxidant and antigenotoxic activities that are comparable to those of ascorbic acid and which have the potential to exert beneficial physiological effects.

     

  • 283.
    Al-Janabi, Ali Waleed Imran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Bokningssystem: Skapandet av ett bokningssystem till en statlig myndighet2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project is about creating a booking system for a government agency, where the agency will offer advance booking to the visitors. The visitors will be able to choose in advance the date and time for the desired meeting and then provide information about what the meeting will be about. The agency also wants information about the booked times. The agency does not have any form of web-based booking system, what the agency currently has is contact during opening hours by telephone calls.  

    The work began by contacting the agency and then creating an idea of what the system should look like, then a list of requirements and time planning for the project was created.  

    The design process begins with gathering information about the existing website that the that the agency uses to adapt the shape of the system to the website and to get an insight into what it might look like. Then market analysis began where different companies that offer such a service were taken up to compare them and get an idea of what such companies offers to the customers who target them.  

    The project was divided into two main areas, namely theory and practical areas. The theory area is about writing the project planning and structuring the project. The practical area is about coding in the form of choice of programming language, implementation of functions and user tests.  

    The result is a fully functional booking system that meets all set goals, as well as a booking system that follows the agency’s requirements. For the system, two different websites were created, one aimed at the visitors, and one aimed at the administration. Both websites are user friendly, relatively secure and take GDPR into account. The result could be confirmed through several different user tests and surveys that were carried out during the project. In the future, it is desired that the booking system can be developed more to reach a higher level of convenience.

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  • 284.
    Aljanabi, Omar
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Computer and System Science.
    Hansen-Haug, Anders
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Computer and System science.
    Virtual Reality (VR) inom ingenjörsutbildningar i Sverige  - Möjligheter och utmaningar2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Virtual reality (VR) is a computer generated 3D representation of real- or fictional environments. VR can be used to create real-life simulations that allow users to experience being present in the environment that being simulated. VR is applied for the purpose of education and training. However, technology takes on a growing role in education as it is considered an alternative to replace traditional teaching. The problem is that research on VR in engineering education is limited and it does not take into account the educators’ point of view regarding VR as an education tool. Which can lead to VR applications that do not hold in reality. The purpose of the study is to investigate VR's current position in engineering education through the identification of opportunities and challenges, based on the educators’ attitude towards VR as an education tool. A qualitative study was carried out to investigate the subject matter. The data for the study was collected via digital trace survey about VR and semi-structured interviews with programmanagers from various engineering programs. The results of the study shows that programmanagers have a positive attitude towards VR and that VR implementation as an education tool is limited within the universities / high schools that were investigated. Furthermore, VR is mostly used for research purposes. The lack of VR's application in education can be due to various factors that are regarded as challenges, which are: lack of confidence in VR-technology, lack of purpose of use and in need for development of VR simulations. There is also opportunities with VR which are: that VR has various positive individual effects, it is cost effective and that VR-laboratories are available for training and development purposes when applying VR.

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  • 285.
    Alkassir, Madonna
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Science, Design, and Sustainable Development (2023-).
    Livscykelanalys och inköpspris av mineralull jämfört medtre olika organiska isoleringsmaterial i en väggkonstruktion ienbostadshus2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The construction industry accounts for a large part ofSweden's greenhouse gas emissions and the largest part ofthese emissions comes from the production of buildings andtransport of building materials. However, the emissions fromheating buildings are getting smaller and smaller thanks tothe use of good insulation materials. It is therefore importantto choose the insulation material that states as low a climateimpact as possible and which at the same time has areasonable price. The purpose of this report is to perform acomparison of mineral wool and organic insulation materialssuch as wood fiber insulation, cellulose insulation and hempfiber insulation in a wall construction using life cycleanalysis LCA and the purchase price to choose the bestinsulation material.In order to get answers to the research questions posed, aliterature study, a case study and document analysis werecarried out. Some calculations that were carried out werealso important in order to decide on the most suitableinsulation material.The results of the report show that mineral wool is the bestinsulation material, as it has the lowest carbon dioxideemissions and the lowest purchase price per square meter.The disadvantage of mineral wool is that it cannot berecycled in the final phase, it ends up in landfill instead.During the construction production phase, the emissionsdiffer quite a lot in phase A4 (transport) and it depends onthe distance between the factories and the company thatbuilds the house.

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  • 286.
    Alkberg, Johanna
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Samarbete i distribuerade team: En analys av möjligheter och metoder för att arbeta distribuerat inom Sandvik IT med stöd av Kanban2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Many companies face the fact that the work must be adapted to the globalization so competitiveness can be maintained. One way to do it is to work geographically distributed and reach competence personnel and more customers while 24/7-work becomes possible. But to effectively work distributed over space and time, a consciousness about the limitations that this entails and how to overcome them are necessary. Sandvik IT is facing changes and the trend is toward more geographically distributed teams. The purpose of this study was therefore focused on the key factors for distributed work and how Kanban can contribute to effective distributed work. How Sandvik IT's supporting group, Service Development Office (SDO) should support the distributed work has also been evaluated. The basic theory is a compilation of literary works such as books and above all scientific articles. From the theory four key areas of distributed work was identified; working methods and coordination, communication, leadership and team spirit. A fifth point was also added, which was about the teamstart. Based on these five areas the interview - and survey questions was formed. SDO selected three teams with informants, and the team leaders/coordinators were interviewed and other staff received the survey. The results were then compared with the initial theory and via analysis 16 key factors for distributed work (at Sandvik IT) could be found. E.g. leader's consciousness, a well-established work method, shared knowledge and social interaction. The factors were also categorized into: Set-up, teams start and finally maintenance and development. To a large extent the key factors and the needs could be met by Kanban, but the recommendation is that SDO complements with (in particular) an education for team leaders/coordinators. It came to be seen as a prerequisite for the distributed work. The survey's response rate and the interviews outcome were good and the result was coherent. Hence the report can be seen as a report with high validity and reliability in an inter-organizational view.

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    Samarbete i distribuerade team
  • 287.
    Alkrot, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    React vs Angular: Slaget om användarupplevelsen2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Lately, various programming frameworks has been developed for developing web applications. These frameworks focus on increasing the user experience by performance improvements such as faster render times and response times. One of these frameworks are React, which has introduced a completely new architectural pattern for both managing the state and data flow of an application. React also offers support for native application development and makes server-side rendering possible. Something that is difficult to accomplish with an application developed with Angular 1.5, which is used by the company Dewire today. The aim of this thesis was to compare React with an existing Angular project, in order to determine whether React could be a potential replacement for Angular. To gain knowledge about the subject, a theoretical study of web- based sources has been made. While the practical part has been to rebuild a web application with React together with the architecture Flux, which is based on a view from the Angular project. The implementation process was repeated until the view was completed and a desired data flow, as in the Angular application, was reached. The resulting React application was later compared with the Angular application developed by the company, where the outcome of the comparison showed that the React performed better than Angular in all tests. In conclusion, due to the timeframe of the project, only the most important parts of the Angular project were implemented in order to carry out the measurements that were of interest to the company. By recreating most of the functionality, or the entire Angular application, more interesting comparisons could have been done.

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    fulltext
  • 288.
    Alkuheli, Hiba
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Communication, Quality Management, and Information Systems (2023-).
    Forsaeus, Lisa
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Communication, Quality Management, and Information Systems (2023-).
    Är en stark kvalitetskultur nyckeln till kvalitetsutmärkelser?: En studie om kvalitetskultur i kommunal verksamhet2023Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The municipalities in Sweden are facing challenges that require the sector to be more effective. Improving the quality of operations is a possible, and seemingly the most attractive, way for municipalities to make themselves more efficient. Businesses with a strong quality culture have greater chances of achieving good quality and results. If links can be found between a strong quality culture and existing good results in municipalities, a quality culture should be of interest for other municipalities to achieve. The present study has therefore investigated whether the municipal management (managers and employees) in two municipalities with recognized high quality has a higher degree of perceived quality culture than two municipalities without quality awards. The purpose of the study has also been to investigate whether there are differences between managers' and employees' views on the organization's quality culture in the selected organizations.  

      

    The data collection method for this study was quantitative with qualitative elements and based on a positivist approach. Questionnaires with the possibility of open text answers were created and sent to four different municipalities, where a total of 70 respondents participated in the study. The respondents were managers and employees in the municipal management in the selected municipalities.   

      

    The results did not show that there is a consistently higher degree of perceived quality culture in municipalities that have received quality awards than in the two municipalities selected in the study that have not received quality awards. The results of the study did however show that there were consistent differences between managers' and employees' perceived quality culture in all the study's themes and in all selected municipalities.

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    fulltext
  • 289.
    Allahgholi, A.
    et al.
    DESY, D-22607 Hamburg, Germany.
    Becker, J.
    DESY, D-22607 Hamburg, Germany.
    Bianco, L.
    DESY, D-22607 Hamburg, Germany.
    Bradford, R.
    Adv Photon Source, Chicago, IL USA.
    Delfs, A.
    DESY, D-22607 Hamburg, Germany.
    Dinapoli, R.
    Paul Scherrer Inst, OFLB-006, CH-5232 Villigen, Switzerland.
    Goettlicher, P.
    DESY, D-22607 Hamburg, Germany.
    Gronewald, M.
    Univ Bonn, D-53115 Bonn, Germany.
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. DESY, D-22607 Hamburg, Germany.
    Greiffenberg, D.
    Paul Scherrer Inst, OFLB-006, CH-5232 Villigen, Switzerland.
    Henrich, B. H.
    Paul Scherrer Inst, OFLB-006, CH-5232 Villigen, Switzerland.
    Hirsemann, H.
    DESY, D-22607 Hamburg, Germany.
    Jack, S.
    DESY, D-22607 Hamburg, Germany.
    Klanner, R.
    Univ Hamburg, D-22761 Hamburg, Germany.
    Klyuev, A.
    DESY, D-22607 Hamburg, Germany.
    Krueger, H.
    Univ Bonn, D-53115 Bonn, Germany.
    Lange, S.
    DESY, D-22607 Hamburg, Germany.
    Marras, A.
    DESY, D-22607 Hamburg, Germany.
    Mezza, D.
    Paul Scherrer Inst, OFLB-006, CH-5232 Villigen, Switzerland.
    Mozzanica, A.
    Paul Scherrer Inst, OFLB-006, CH-5232 Villigen, Switzerland.
    Perova, I.
    DESY, D-22607 Hamburg, Germany.
    Xia, Q.
    DESY, D-22607 Hamburg, Germany.
    Schmitt, B.
    Paul Scherrer Inst, OFLB-006, CH-5232 Villigen, Switzerland.
    Schwandt, J.
    Univ Hamburg, D-22761 Hamburg, Germany.
    Sheviakov, I.
    DESY, D-22607 Hamburg, Germany.
    Shi, X.
    Paul Scherrer Inst, OFLB-006, CH-5232 Villigen, Switzerland.
    Trunk, U.
    DESY, D-22607 Hamburg, Germany.
    Zhang, J.
    DESY, D-22607 Hamburg, Germany.
    The adaptive gain integrating pixel detector2016In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 11, no 2, article id C02066Article in journal (Refereed)
    Abstract [en]

    The adaptive gain integrating pixel detector (AGIPD) is a development of a collaboration between Deustsches Elektronen-Synchrotron (DESY), the Paul-Scherrer-Institute (PSI), the University of Hamburg and the University of Bonn. The detector is designed to cope with the demanding challenges of the European XFEL. Therefore it comes along with an adaptive gain stage allowing a high dynamic range, spanning from single photon sensitivity to 10(4) x 12.4 keV photons and 352 analogue memory cells per pixel. The aim of this report is to briefly explain the concepts of the AGIPD electronics and mechanics and then present recent experiments demonstrating the functionality of its key features.

  • 290.
    Allahgholi, A.
    et al.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Becker, J.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany; Cornell University, Ithaca, NY, United States .
    Bianco, L.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Delfs, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Arino-Estrada, G.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Gottlicher, P.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Hirsemann, H.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Jack, S.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Klyuev, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Lange, S.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Marras, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Poehlsen, J.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Sheviakov, I.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Trunk, U.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Xia, Q.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Zhang, J.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Zimmer, M.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany.
    Dinapoli, R.
    PSI, Villigen, Switzerland.
    Greiffenberg, D.
    PSI, Villigen, Switzerland.
    Mezza, D.
    PSI, Villigen, Switzerland.
    Mozzanica, A.
    PSI, Villigen, Switzerland.
    Schmitt, B.
    PSI, Villigen, Switzerland.
    Shi, X.
    PSI, Villigen, Switzerland.
    Klanner, R.
    University of Hamburg, Germany.
    Schwandt, J.
    University of Hamburg, Germany.
    Kruger, H.
    University of Bonn, Germany.
    Rah, S.
    Pohang Accelerator Laboratory, Pohang, South Korea.
    The AGIPD 1.0 ASIC: Random access high frame rate, high dynamic range X-ray camera readout for the European XFEL2015In: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015, Institute of Electrical and Electronics Engineers (IEEE), 2015, article id 7581819Conference paper (Refereed)
    Abstract [en]

    The European XFEL is an extremely brilliant Free Electron Laser Source with a very demanding pulse structure: trains of 2700 X-Ray pulses are repeated at 10 Hz. The pulses inside the train are spaced by 220 ns and each one contains up to 1012 photons of 12.4 keV, while being ≤ 100 fs in length. AGIPD (Adaptive Gain Integrating Pixel Detector) is a hybrid 1M-pixel detector developed by DESY, PSI, and the Universities of Bonn and Hamburg to cope with these properties. Thus the readout ASIC has to provide not only single photon sensitivity and a dynamic range ≳ 104 photons/pixel in the same image but also a memory for as many images of a pulse train as possible for delayed readout prior to the next train. The AGIPD 1.0 ASIC uses a 130 nm CMOS technology and radiation tolerant techniques to withstand the radiation damage incurred by the high impinging photon flux. Each ASIC contains 64 × 64 pixels of 200μmχ200μm. The circuit of each pixel contains a charge sensitive preamplifier with threefold switchable gain, a discriminator for an adaptive gain selection, and a correlated double sampling (CDS) stage to remove reset and low-frequency noise components. The output of the CDS, as well as the dynamically selected gain is sampled in a capacitor-based analogue memory for 352 samples, which occupies about 80% of a pixels area. For readout each pixel features a charge sensitive buffer. A control circuit with a command based interface provides random access to the memory and controls the row-wise readout of the data via multiplexers to four differential analogue ports. The AGIPD 1.0 full scale ASIC has been received back from the foundry in fall of 2013. Since then it has been extensively characterised also with a sensor as a single chip and in 2 × 8-chip modules for the AGIPD 1 Mpix detector. We present the design of the AGIPD 1.0 ASIC along with supporting results, also from beam tests at PETRA III and APS, and show changes incorporated in the recently taped out AGIPD 1.1 ASIC upgrade.

  • 291.
    Allahgholi, A.
    et al.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Becker, J.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Bianco, L.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Delfs, A.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Dinapoli, R.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Arino-Estrada, G.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Goettlicher, P.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Greiffenberg, D.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Hirsemann, H.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Jack, S.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Klanner, R.
    Univ Hamburg, Mittelweg 177, D-20148 Hamburg, Germany.
    Klyuev, A.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Krueger, H.
    Univ Bonn, D-53012 Bonn, Germany.
    Lange, S.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Marras, A.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Mezza, D.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Mozzanica, A.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Poehlsen, J.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Rah, S.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Xia, Q.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Schmitt, B.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Schwandt, J.
    Univ Hamburg, Mittelweg 177, D-20148 Hamburg, Germany.
    Sheviakov, I.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Shi, X.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Smoljanin, S.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Trunk, U.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Zhang, J.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Zimmer, M.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Front end ASIC for AGIPD, a high dynamic range fast detector for the European XFEL2016In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 11, no 1, article id C01057Article in journal (Refereed)
    Abstract [en]

    The Adaptive Gain Integrating Pixel Detector (AGIPD) is a hybrid pixel X-ray detector for the European-XFEL. One of the detector's important parts is the radiation tolerant front end ASIC fulfilling the European-XFEL requirements: high dynamic range-from sensitivity to single 12.5keV-photons up to 104 photons. It is implemented using the dynamic gain switching technique with three possible gains of the charge sensitive preamplifier. Each pixel can store up to 352 images in memory operated in random-access mode at >= 4.5MHz frame rate. An external vetoing may be applied to overwrite unwanted frames.

  • 292.
    Allahgholi, A.
    et al.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Becker, J.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Bianco, L.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Delfs, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Dinapoli, R.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Fretwurst, E.
    University of Bonn, Bonn, Germany.
    Göttlicher, P.
    University of Hamburg, Hamburg, Germany.
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Greiffenberg, D.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Gronewald, M.
    University of Bonn, Bonn, Germany.
    Hirsemann, H.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Jack, S.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Klanner, R.
    University of Bonn, Bonn, Germany.
    Klyuev, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Krüger, H.
    University of Bonn, Bonn, Germany.
    Marras, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Mezza, D.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Mozzanica, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Schmitt, B.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Schwandt, J.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Sheviakov, I.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Shi, X.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Xia, Q.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Zhang, J.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Zimmer, M.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    AGIPD, the electronics for a high speed X-ray imager at the Eu-XFEL2014In: Proceedings of Science, Proceedings of Science (PoS) , 2014, article id 253Conference paper (Refereed)
    Abstract [en]

    The AGIPD (Adaptive Gain Integrated Pixel Detector) X-ray imaging camera will be operated at the X-ray Free Electron Laser, Eu-XFEL, under construction in Hamburg, Germany. Key parameters are 1 million 200 μm square pixels, single 12.4 keV photon detection and a dynamic range to 10 000/pixel/image. The developed sensors, ASICs, PCB-electronics and FPGA firmware acquire individual images per bunch at 27 000 bunches/s, packed into 10 bunch-trains/s with a bunch separation of 222 ns. Bunch-trains are handled by 352 analogue storage cells within each pixel of the ASIC and written during the 0.6msec train delivery. Therefore AGIPD can store 3520 images/s from the delivered 27 000 bunches/s. Random addressing provides reusability of each cell after an image has been declared as low-quality, so that good images can be selected. Digitization is performed between trains (99.4 msec). In the paper all functional blocks are introduced. The details concentrate on the DAQ-chain PCB-electronics and the slow control. A dense area of 1024 ADC-channels, each with a pickup-noise filtering and sampling of up to 50 MS/s/ADC and a serial output of 700 Mbit/s/ADC. FPGAs operate the ASICs synchronized to the bunch structure and collect the bit streams from 64 ADCs/FPGA. Pre-sorted data is transmitted on 10 GbE links out of the camera head using the time between trains. The control and monitoring of the camera with 600 A current consumption is based on a micro-controller and I2C bus with an addressing architecture allowing many devices and identical modules. The high currents require planned return paths at the system level. First experimental experience with the constructed components will be presented.

  • 293.
    Allahgholi, A.
    et al.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Becker, J.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Bianco, L.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Delfs, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Dinapoli, R.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Goettlicher, P.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany.;Mid Sweden Univ, S-85170 Sundsvall, Sweden.
    Greiffenberg, D.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Hirsemann, H.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Jack, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Klanner, R.
    Univ Hamburg, D-20148 Hamburg, Germany..
    Klyuev, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Krueger, H.
    Univ Bonn, D-53012 Bonn, Germany..
    Lange, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Marras, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Mezza, D.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Mozzanica, A.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Rah, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Xia, Q.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Schmitt, B.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Schwandt, J.
    Univ Hamburg, D-20148 Hamburg, Germany.
    Sheviakov, I.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Shi, X.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Smoljanin, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Trunk, U.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Zhang, J.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Zimmer, M.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    AGIPD, a high dynamic range fast detector for the European XFEL2015In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 10, no 1, article id C01023Article in journal (Refereed)
    Abstract [en]

    AGIPD-(Adaptive Gain Integrating Pixel Detector) is a hybrid pixel X-ray detector developed by a collaboration between Deutsches Elektronen-Synchrotron (DESY), Paul-Scherrer-Institut (PSI), University of Hamburg and the University of Bonn. The detector is designed to comply with the requirements of the European XFEL. The radiation tolerant Application Specific Integrated Circuit (ASIC) is designed with the following highlights: high dynamic range, spanning from single photon sensitivity up to 10(4) 12.5keV photons, achieved by the use of the dynamic gain switching technique using 3 possible gains of the charge sensitive preamplifier. In order to store the image data, the ASIC incorporates 352 analog memory cells per pixel, allowing also to store 3 voltage levels corresponding to the selected gain. It is operated in random-access mode at 4.5MHz frame rate. The data acquisition is done during the 99.4ms between the bunch trains. The AGIPD has a pixel area of 200 x 200 m m(2) and a 500 m m thick silicon sensor is used. The architecture principles were proven in different experiments and the ASIC characterization was done with a series of development prototypes. The mechanical concept was developed in the close contact with the XFEL beamline scientists and is now being manufactured. A first single module system was successfully tested at APS.

  • 294.
    Allahgholi, A.
    et al.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Becker, J.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Bianco, L.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Delfs, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Gottlicher, P.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Hirsemann, H.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Jack, S.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Klyuev, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Lange, S.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Marras, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Sheviakov, I.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Trunk, U.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Xia, Q.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Zhang, J.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Zimmer, M.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Dinapoli, R.
    PSI, Villigen, Switzerland .
    Greiffenberg, D.
    PSI, Villigen, Switzerland .
    Mezza, D.
    PSI, Villigen, Switzerland .
    Mozzanica, A.
    PSI, Villigen, Switzerland .
    Schmitt, B.
    PSI, Villigen, Switzerland .
    Shi, X.
    PSI, Villigen, Switzerland .
    Klanner, R.
    University of Hamburg, Germany .
    Schwandt, J.
    University of Hamburg, Germany .
    Gronewald, M.
    University of Bonn, Germany .
    Kruger, H.
    University of Bonn, Germany .
    Rah, S.
    Pohang Accelerator Laboratory, Pohang, South Korea .
    AGIPD 1.0: The high-speed high dynamic range readout ASIC for the adaptive gain integrating pixel detector at the European XFEL2014In: 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014, Institute of Electrical and Electronics Engineers (IEEE), 2014, article id 7431038Conference paper (Refereed)
    Abstract [en]

    AGIPD is a hybrid pixel X-ray detector developed by a collaboration between Deutsches Elektronen-Synchrotron (DESY), Paul-Scherrer-Institute (PSI), University of Hamburg and the University of Bonn. The detector is designed to comply with the requirements of the European XFEL. The radiation tolerant Application Specific Integrated Circuit (ASIC) is designed with the following highlights: high dynamic range, spanning from single photon sensitivity up to 104 × 12.4 keV photons, achieved by the use of dynamic gain switching, auto-selecting one of 3 gains of the charge sensitive pre-amplifier. To cope with the unique features of the European XFEL source, image data is stored in 352 analogue memory cells per pixel. The selected gain is stored in the same way and depth, encoded as one of 3 voltage levels. These memories are operated in random-access mode at 4.5MHz frame rate. Data is read out on a row-by-row basis via multiplexers to the DAQ system for digitisation during the 99.4ms gap between the bunch trains of the European XFEL. The AGIPD 1.0 ASIC features 64×64 pixels with a pixel area of 200×200 μm2. It is bump-bonded to a 500 μm thick silicon sensor. The principles of the chip architecture were proven in different experiments and the ASIC characterization was performed with a series of development prototypes. The mechanical concept of the detector system was developed in close contact with the XFEL beamline scientists to ensure a seamless integration into the beamline setup and is currently being manufactured. The first single module system was successfully tested at APS1 the high dynamic range allows imaging of the direct synchrotron beam along with single photon sensitivity and burst imaging of 352 subsequent frames synchronized to the source.

  • 295.
    Allahgholi, Aschkan
    et al.
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Becker, Julian
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Delfs, Annette
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Dinapoli, Roberto
    Paul Scherrer Inst, Villigen, Switzerland.
    Goettlicher, Peter
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Greiffenberg, Dominic
    Paul Scherrer Inst, Villigen, Switzerland.
    Henrich, Beat
    Paul Scherrer Inst, Villigen, Switzerland.
    Hirsemann, Helmut
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Kuhn, Manuela
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Klanner, Robert
    Univ Hamburg, Hamburg, Germany.
    Klyuev, Alexander
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Krueger, Hans
    Univ Bonn, Bonn, Germany.
    Lange, Sabine
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Laurus, Torsten
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Marras, Alessandro
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Mezza, Davide
    Paul Scherrer Inst, Villigen, Switzerland.
    Mozzanica, Aldo
    Paul Scherrer Inst, Villigen, Switzerland.
    Niemann, Magdalena
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Poehlsen, Jennifer
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Schwandt, Joern
    Univ Hamburg, Hamburg, Germany.
    Sheviakov, Igor
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Shi, Xintian
    Paul Scherrer Inst, Villigen, Switzerland.
    Smoljanin, Sergej
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Steffen, Lothar
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Sztuk-Dambietz, Jolanta
    European XFEL, Schenefeld, Germany.
    Trunk, Ulrich
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Xia, Qingqing
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Zeribi, Mourad
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Zhang, Jiaguo
    Paul Scherrer Inst, Villigen, Switzerland.
    Zimmer, Manfred
    Deutsch Elekt Synchrotron, Hamburg, Germany.
    Schmitt, Bernd
    Paul Scherrer Inst, Villigen, Switzerland.
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Deutsch Elekt Synchrotron, Hamburg, Germany.
    The Adaptive Gain Integrating Pixel Detector at the European XFEL2019In: Journal of Synchrotron Radiation, ISSN 0909-0495, E-ISSN 1600-5775, Vol. 26, p. 74-82Article in journal (Refereed)
    Abstract [en]

    The Adaptive Gain Integrating Pixel Detector (AGIPD) is an X-ray imager, custom designed for the European X-ray Free-Electron Laser (XFEL). It is a fast, low-noise integrating detector, with an adaptive gain amplifier per pixel. This has an equivalent noise of less than 1keV when detecting single photons and, when switched into another gain state, a dynamic range of more than 10(4)photons of 12keV. In burst mode the system is able to store 352 images while running at up to 6.5MHz, which is compatible with the 4.5MHz frame rate at the European XFEL. The AGIPD system was installed and commissioned in August 2017, and successfully used for the first experiments at the Single Particles, Clusters and Biomolecules (SPB) experimental station at the European XFEL since September 2017. This paper describes the principal components and performance parameters of the system.

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  • 296.
    Allahgholi, Aschkan
    et al.
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Becker, Julian
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Delfs, Annette
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Dinapoli, Roberto
    Paul Scherrer Institut - PSI, Villigen, Switzerland.
    Göttlicher, Peter
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Greiffenberg, Dominic
    Paul Scherrer Institut - PSI, Villigen, Switzerland.
    Hirsemann, Helmut
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Jack, Stefanie
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Klyuev, Alexander
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Krüger, Hans
    Universität Bonn, Bonn, Germany.
    Kuhn, Manuela
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Laurus, Torsten
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Marras, Alessandro
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Mezza, Davide
    Paul Scherrer Institut - PSI, Villigen, Switzerland.
    Mozzanica, Aldo
    Paul Scherrer Institut - PSI, Villigen, Switzerland.
    Poehlsen, Jennifer
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Shefer Shalev, Ofir
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Sheviakov, Igor
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Schmitt, Bernd
    Paul Scherrer Institut - PSI, Villigen, Switzerland.
    Schwandt, Jörn
    Universität Hamburg, Hamburg, Germany.
    Shi, Xintian
    Paul Scherrer Institut - PSI, Villigen, Switzerland.
    Smoljanin, Sergej
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Trunk, Ulrich
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Zhang, Jiaguo
    Paul Scherrer Institut - PSI, Villigen, Switzerland.
    Zimmer, Manfred
    Deutsches Elektronensynchrotron - DESY, Hamburg, Germany.
    Megapixels @ Megahertz – The AGIPD high-speed cameras for the European XFEL2019In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 942, article id 162324Article, review/survey (Refereed)
    Abstract [en]

    The European XFEL is an extremely brilliant Free Electron Laser Source with a very demanding pulse structure: trains of 2700 X-ray pulses are repeated at 10Hz. The pulses inside the train are spaced by 220ns and each one contains up to 1012photons of 12.4keV, while being ≤100fs in length. AGIPD, the Adaptive Gain Integrating Pixel Detector, is a hybrid pixel detector developed by DESY, PSI, and the Universities of Bonn and Hamburg to cope with these properties. It is a fast, low noise integrating detector, with single photon sensitivity (for Eγ⪆6keV) and a large dynamic range, up to 104 photons at 12.4keV. This is achieved with a charge sensitive amplifier with 3 adaptively selected gains per pixel. 352 images can be recorded at up to 6.5MHz and stored in the in-pixel analogue memory and read out between pulse trains. The core component of this detector is the AGIPD ASIC, which consists of 64 × 64 pixels of 200µm×200µm. Control of the ASIC's image acquisition and analogue readout is via a command based interface. FPGA based electronic boards, controlling ASIC operation, image digitisation and 10GE data transmission interface AGIPD detectors to DAQ and control systems. An AGIPD 1Mpixel detector has been installed at the SPB1 experimental station in August 2017, while a second one is currently commissioned for the MID 2 endstation. A larger (4Mpixel) AGIPD detector and one to employ Hi-Z sensor material to efficiently register photons up to Eγ≈25keV are currently under construction. 

  • 297. Allain, J. P.
    et al.
    Dong, Y.
    Vandamme, A. M.
    Moulton, Vincent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Salemi, M.
    Evolutionary rate and genetic drift of hepatitis C virus are not correlated with the host immune response: Studies of infected donor-recipient clusters2000In: Journal of Virology, ISSN 0022-538X, E-ISSN 1098-5514, Vol. 74, no 6, p. 2541-2549Article in journal (Refereed)
    Abstract [en]

    Six donor-recipient clusters of hepatitis C virus (HCV)-infected individuals were studied. For five clusters the period of infection of the donor could be estimated, and for all six clusters the time of infection of the recipients from the donor via blood transfusion was also precisely known. Detailed phylogenetic analyses were carried out to investigate the genomic evolution of the viral quasispecies within infected individuals in each cluster. The molecular clock analysis showed that HCV quasispecies within a patient are evolving at the same rate and that donors that have been infected for longer time tend to have a lower evolutionary rate. Phylogenetic analysis based on the split decomposition method revealed different evolutionary patterns in different donor-recipient clusters. Reactivity of antibody against the first hypervariable region (HVR1) of HCV in donor and recipient sera was evaluated and correlated to the calculated evolutionary rate. Results indicate that anti-HVR1 reactivity was related more to the overall level of humoral immune response of the host than to the HVR1 sequence itself, suggesting that the particular sequence of the HVR1 peptides is not the determinant of reactivity. Moreover, no correlation was found between the evolutionary rate or the heterogeneity of the viral quasispecies in the patients and the strength of the immune response to HVR1 epitopes, Rather, the results seem to imply that genetic drift is less dependent on immune pressure than on the rate of evolution and that the genetic drift of HCV is independent of the host immune pressure.

  • 298.
    Aller, Elin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Design.
    Kött och blod2020Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
  • 299.
    Allison, Hernandez Escalante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Design.
    Digitalisering av en turistbyrå2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Examensarbete för Mittuniversitetet kandidatprogram Industridesign. Projektet genomfördes i samarbete med Stenstan visitor center och Näringslivsbolaget i Sundsvall. Syftet med examensarbetet var att erbjuda en digital besöksservice som ska informera och nå ut till en större antal besökare. Målsättningen var att ge en försmak på vad Sundsvall har att erbjuda, få besökaren att ta del av stenstans resa och förbättra besökarupplevelsen genom att underlätta besöksmönstret och samtidigt skapa en positiv besökarupplevelse.

    Det slutgiltiga resultatet blev en digital besöksservice vars funktion är att både assistera och ge ut värdefull information till besökaren. Tjänsten använder sig främst av AR teknik för att informera samt vägleda besökaren i Sundsvall. Men även VR upplevelser ska finnas tillgängliga i tjänsten, Tjänstens huvudsakliga funktion blev att erbjuda information på ett enkelt och smidigt sätt för att besökaren ska få en så trivsam upplevelse som möjligt. Informationen ges i form av en karta som även har en guidande funktion, vilket tillåter besökaren att enkelt ta sig runt i staden med hjälp av AR teknik.

     

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  • 300.
    Allison, Robert S.
    et al.
    York University, Centre for Vision Research, Toronto, Canada.
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology. RISE AB (Acreo).
    Chandler, Damon M.
    Shizuoka University, Hamamatsu, Shizuoka, Japan.
    Colett, Hannah R.
    Intel Corp., Santa Clara, California, United States.
    Corriveau, Philip J.
    Intel Corp., Santa Clara, California, United States.
    Daly, Scott
    Dolby Laboratories Inc., Sunnyvale, California, United States.
    Goel, James
    Qualcomm Technologies, Inc., Display Video Processing Group, Markham, Canada.
    Long, Juliana Y.
    Intel Corp., Santa Clara, California, United States.
    Wilcox, Laurie M.
    York University, Centre for Vision Research, Toronto, Canada.
    Yaacob, Yusizwan M.
    Shizuoka University, Hamamatsu, Shizuoka, Japan.
    Yang, Shun-nan
    Pacific University, Forest Grove, Oregon, United States.
    Zhang, Yi
    Xi’an Jiaotong University, School of Electronic and Information Engineering, Xi’an, China.
    Perspectives on the definition of visually lossless quality for mobile and large format displays2018In: Journal of Electronic Imaging (JEI), ISSN 1017-9909, E-ISSN 1560-229X, Vol. 27, no 5, p. 1-23, article id 053035Article in journal (Refereed)
    Abstract [en]

    Advances in imaging and display engineering have given rise to new and improved image and videoapplications that aim to maximize visual quality under given resource constraints (e.g., power, bandwidth).Because the human visual system is an imperfect sensor, the images/videos can be represented in a mathematicallylossy fashion but with enough fidelity that the losses are visually imperceptible—commonly termed“visually lossless.” Although a great deal of research has focused on gaining a better understanding ofthe limits of human vision when viewing natural images/video, a universally or even largely accepted definitionof visually lossless remains elusive. Differences in testing methodologies, research objectives, and targetapplications have led to multiple ad-hoc definitions that are often difficult to compare to or otherwise employ inother settings. We present a compendium of technical experiments relating to both vision science and visualquality testing that together explore the research and business perspectives of visually lossless image quality,as well as review recent scientific advances. Together, the studies presented in this paper suggest that a singledefinition of visually lossless quality might not be appropriate; rather, a better goal would be to establish varyinglevels of visually lossless quality that can be quantified in terms of the testing paradigm.

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