Sustainability has become an increasingly relevant topic today where companies face societal pressure to contribute through sustainability efforts. The IT sector is rapidly changing with technological development, making research on sustainability strategies quickly outdated. Therefore, a qualitative case study was conducted on an IT consultancy firm. The aim of the study was to provide new insight into the interpretation of sustainability for an IT consultancy firm, as well as the driving forces and challenges associated with their sustainability strategy. To achieve this goal, semi-structured interviews were conducted with participants selected through snowball sampling. The interviews were then analyzed using a thematic analysis approach, where the interviews were transcribed, transformed into codes, and finally sorted into themes. The results showed that the IT consulting firm worked with the following policies for its sustainability strategy: procurement, waste sorting, carbon-free transportation, sustainable working hours, gender equality, and sustainable consultants. Employees were central to the development and implementation of these policies. Another factor in the development of these policies was external forces such as new regulations. The policies are processed through the employees or the external force and then moved on to the management group, which consists of all office managers. The driving forces identified were a moral duty, a competitive advantage for employees and customers, financial benefits, and risk management. The attractiveness for the recruitment of new employees could be considered the most important driving force as the topic is so relevant among the new generation. The challenges identified were finding the right type of policy and the difficulty of measuring sustainability work, which supports previous research even though there are protocols for measuring sustainability work. / Hållbarhet har blivit ett alltmer aktuellt ämne idag där företag har pressen från samhället att bidra genom hållbarhetsarbeten.  IT-sektorn ändras snabbt med teknikutveckling där forskning om hållbarhetsstrategier snabbt kan bli föråldrat. Därav gjordes en kvalitativ fallstudie på ett IT-konsultbolag. Målet med studien var att framföra nytt underlag på tolkningen av hållbarhet för ett IT-konsultbolag samt vilka drivkrafter och hinder det kan finnas med deras hållbarhetsstrategi. För att uppnå målet gjordes semistrukturerade intervjuer där urvalet valdes genom metoden snöbollsurval.  Efter intervjuerna gjordes en analys inspirerad av tematiskanalys. Där intervjuerna transkriberades och omvandlades sedan till koder och slutligen sorterade till teman. Resultatet visade att IT-konsultbolaget arbetade med följande policys för sin hållbarhetsstrategi: inköp, källsortering, koldioxidfria transportmedel, hållbara arbetstider, jämställdhet och hållbara konsulter. Där medarbetaren var centrala kring policys och framtagandet av policys. En annan faktor till framtagande av policys var externa krafter som ny reglering. Framtagandet av policys går igenom medarbetarna eller den externa kraften för att sedan gå vidare till ledningsgruppen som består av alla kontorschefer. De drivkrafter som hittades var moralisk plikt, konkurrensfördel för medarbetare och kunder, finansiella fördelar och riskhantering. Där attraktivitet för rekrytering av nya medarbetare kunde anses som den drivkraften som vägde mest då ämnet är så aktuellt bland den nya generationen. De hinder som hittades var hitta rätt typ av policy och svårigheten att mäta hållbarhetsarbetet. Vilket stödjer tidigare forskning trots att det existerar protokoll för att mäta hållbarhetsarbete.

全球行動電話用戶數於2002年達到12億，首度超過固定電話用戶數之11億；行動電話用戶數並於2008年達41億，為固定電話用戶數(13億)之3倍以上。行動電話相對於固定電話之主要優勢在於系統之建置成本低及佈建速度快；行動電話之快速普及已成為創新擴散研究之重要題材。 行動電話擴散之研究為選取一成長模型(例如Gompertz、Logistic或Bass模型)並類比該模型以求出擴散之參數(例如成長速率)，以進一步(1)了解相關驅動因子(例如技術創新、市場開放等)對擴散參數之影響，及(2)延伸擴散模型曲線以預測未來之成長。 惟成長模型之選取尚無原理原則可供遵循而具隨機性(ad hoc basis)。為找出模型選用之可能規律，以降低模型選用之隨機性並提高成長預測之準確度，本研究以十二個代表性國家(巴、中、法、德、印、日、韓、俄、星、台、英、美)至2007年之資料以比較三個最常用之成長模型之績效，即Gompertz、Logistic及Bass模型。模型績效逐年比較標準係採用rmse值，並輔以Friedman test檢測模型績效差異之顯著性，再對照模型之機制意涵，以進一步了解最適模型之選用原則。 此外，台灣行動電話普及率於2002年為108%居全球之冠，而中國自2001年起取代美國成為全球具最多行動電話用戶數之單一國家，台灣及中國屬行動電話擴散之重要個案，惟目前尚缺此二個案之實證研究。為補足此一缺口，本研究亦對台灣及中國行動電話擴散之驅動因子進行實證研究，以進一步了解擴散之關鍵驅動力。 研究發現由於目前統計軟體之進步，Gompertz、Logistic及Bass三模型均可獲致極佳之匹配度而難分軒輊，惟模型預測力(延伸曲線)則具差異性。12個模型選用樣本國家中之8個國家(巴、中、法、德、日、韓、英、美)係以Gompertz模型具較佳之預測力；依Gompertz模型機制意涵，代表行動電話擴散早期係受網路外部性(口耳相傳)影響，惟至擴散後期(例如過了擴散極大值之一半)則已不相關。此外，若因市場開放等重大變因造成行動電話之快速擴散，則Logistic模型具有較佳之績效，如台灣及俄羅斯屬之。依Logistic模型機制意涵，代表擴散係受網路外部性所影響。Bass模型應用於行動電擴散時，因該模型所算出之創新係數偏低，績效與Logistic模型相近，而Logistic模型為Bass模型之創新係數為0時之特例。 台灣及中國行動電話擴散之驅動因子研究發現(1)價格下降及(2)預付卡之推行對加速擴散具顯著性，兩者均對低階市場之採用具影響力。鑑於高階市場將先飽和，爰未來加速行動電話擴散之關鍵驅動因子應係與推動低階市場採用具密切相關性。以中國為例，未來市場開放競爭造成價格再度大幅下降，將進一步促低階市場採用，加速中國行動電話之普及。 / The number of mobile telephone subscriptions reached 1.2 billion globally in 2002, exceeding fixed-line telephony subscriptions (1.1 billion) for the first time. The number of mobile telephone subscriptions reached 4.1 billion globally in 2008, over three times the number of fixed-line telephone subscriptions (1.3 billion). The main advantages of mobile telephony over fixed-line are low cost and rapid facility deployment. The rapid diffusion of mobile telephony has become an important topic in innovation diffusion. The conventional approach to studying mobile telephony diffusion is to analogize a single growth model, such as the Gompertz, Logistic or Bass model, and calculate the model parameters, for example growth rate. The significance of certain selected driving forces, such as technology innovation or market competition, to the studied parameters, such as growth rate, is then estimated. The diffusion growth can also be forecast by extrapolating the diffusion curve. Utilizing the growth model analogy is the first step in analyzing mobile telephony diffusion. However, no principles or rules exit for selecting a growth model. To identify rules for model selection to reduce randomness and increase forecast accuracy, this work uses 12 sample countries, namely Brazil, China, France, Germany, India, Japan, Korea, Russia, Singapore, Taiwan, the UK and the USA, employing data prior to 2008 to compare the performance of three most commonly used models, namely the Gompertz, Logistic and Bass models. The root mean square error (rmse) is chosen as the criterion for measuring annual model performance. The work uses the Friedman test to examine the significance of differences in performance between models. The implications of model mechanisms are emphasized to investigate the selection rule for the most appropriate model. The penetration of mobile telephony in Taiwan was 108% in 2002, ranking first in the world. Furthermore, in 2001 the number of mobile telephony in China replaced the United States as number one in the world. Both Taiwan and China are important examples for mobile telephony diffusion. However, no empirical investigation has been performed in these two cases. To fill this gap, this work estimated the driving forces for mobile telephony diffusion in Taiwan and China to learn about the critical drivers of the mobile telephony diffusion. Empirical results indicate that due to improvements in statistical software, providing good fitness for all three models, namely the Gompertz, Logistic and Bass models, distinguishing which has the best fitness is difficult. However, the performance of the three models is distinguishable when forecasting based on extrapolating the diffusion curve. In eight of the 12 examples, namely Brazil, China, France, Germany, Japan, Korea, the UK and the USA, the Gompertz model is the most appropriate model for forecasting. The mechanism of the Gompertz model means that during the initial stage the diffusion is correlated with network externalities (namely word of mouth), however, this correlation reduces during the later stages (such as pass one half of the maximum potential). Moreover, the cases of Taiwan and Russia demonstrated that the Logistic model performs well provided some significant driver of the diffusion exists. The mechanism of the Logistic model means that the diffusion is correlated with network externalities throughout the whole diffusion. Furthermore, using Chinese data, when the Bass model is applied, because of its low innovation coefficient, it performs similarly to the Logistic model, which is a special case of the Bass model in which the innovation coefficient equals zero. Empirical results for the critical driving forces of mobile telephony diffusion in Taiwan and China indicate that (1) reducing prices and (2) the launch of pre-paid services are crucial to mobile telephony diffusion. Both factors are essential to mobile telephony adoption in low-end markets. The high-end market is the first to be saturated by mobile telephony adoption, future drivers of the mobile telephony diffusion should be highly correlated with low-end market demand. Taking China as an example, the opening of the market to further reduce tariffs will attract mobile telephony adoption in the low-end market, facilitating the mobile telephony diffusion.

Building Information Modeling, abbreviated BIM, is a process of information sharing which enhances communication and which helps in visualizing complex problems in the building industry. BIM has not been used in a larger extent in the production phase of civil works. The purpose of the study is therefore to investigate driving forces behind the use of BIM and the resistors against it and to investigate in what ways BIM could be used in the production phase.The theoretical framework is based on one licentiate thesis, two degree projects, three research papers and three books. A qualitative method with semi-structured interviews was used. The interviews were made with a calculator, a supervisor and a CAD planner from Skanska, a constructor and project manager from ELU, a Project Information Officer from Tyréns and a VDC coordinator and VDC business developer from Veidekke who all have been working with BIM. This was to get a good representation from different actors and people with different professional roles.The study shows that the driving forces behind a use of BIM are that it enhances collaboration and communication between the actors, it makes it easier to visualize the project and the scope, and it provides a higher degree of accuracy of coordination’s. BIM also makes the work more effective and results in fewer errors. Above all, BIM give a possibility for a shorter production phase, shorter total project duration and a lower total cost. The study also shows that the resistors against the use of BIM are employee’s negative attitude against administrative work, that it is hard to measure profitability of using BIM, the uncertainty of who has the legal ownership of the data, and who has the responsibility of the accuracy of it. That the implementation cost and the design phase are more expensive is also a resistor against a use of BIM.BIM could be used in visualization with 3D models in collision controls and co-reviews in meetings, work preparations and at site. A workplace outline could also be printed from the 3D model to be placed on the site for visualization. 4D scheduling and 4D animations could be used for visualization in meetings, work preparations and at site. The study showed that quantity takeoff and cost estimation with 5D is only reconciled in the meetings in the production phase and that the programs for it are not needed in this phase. RFID tags could be used at site for logistics and tracking materials, and field verifications could be used to verify that a work task is executed according to exact coordination’s in the 3D model. Furthermore tablet computers could be used for bringing the technique of BIM to the site which enables a better understanding of complex work tasks for the workers. A BIM coordinator who understands the process of working with BIM and who could work as a bridge between the users and the technical development team is important in a successful implementation.The study also shows that the focus of BIM should lie on how to make use of the technique. The examples of how BIM could be used in the production phase of civil works have to be useful and meet the needs and demands of the users. The processes of using 3D models, 4D scheduling, 4D animations, RFID tags, field verifications and tablet computers should therefore be studied thoroughly to find how the technique could be applicable at site, in meetings and work preparations and how it could enhance the daily activities and work tasks. If the demands are met it will be accepted by both the user and the organization. Further research should therefore lie on how 3D models, 4D scheduling, 4D animations, RFID tags, field verifications and tablet computers could be useful in the production phase. These BIM techniques should then be tested on a real project to investigate how the processes could be useful at site, in meetings and in work preparations. Further research should also be made on how countries like Norway, Finland and USA have made use of BIM in the production of civil works. / Bygginformationsmodellering, förkortat BIM, är en process för informationsutbyte som förbättrar kommunikation samt förståelsen för komplexa problem inom byggbranschen. BIM har inte använts i en större utsträckning i produktionen av väg- och anläggningsprojekt. Syftet med studien är därför att undersöka drivkrafter bakom ett större användande av BIM och motstånd mot det, samt att undersöka på vilket sätt BIM skulle kunna vara användbart i produktionen.Den teoretiska grunden bygger på en licentiathandling, två examensarbeten, tre forskningsrapporter samt tre böcker. För intervjuerna användes en kvantitativ semistrukturerad metod. Intervjuerna gjordes med en kalkylator, en arbetsledare från Skanska, en CAD planerare från ELU, en Project Information Officer från Tyréns samt en VDC samordnare och VDC affärsutvecklare från Veidekke, som alla har arbetat med BIM. Detta var för att få en bra representation från olika aktörer och personer med skilda yrkesroller.Studien visar att drivkrafterna bakom en användning av BIM är att det förbättrar samarbetet och kommunikationen mellan aktörerna, gör det lättare att visualisera projektet, dess omfattning samt att det ger mer korrekta data. BIM gör också arbetet mer effektivt och resulterar i färre fel. Framförallt möjliggör BIM en kortare produktionsfas, kortare projekttid och lägre totalkostnad. Studien visar också att anställdas negativa attityd mot administrativt arbete är ett av motstånden mot en större användning av BIM, att det är svårt att mäta lönsamheten med det och att det är osäkert om vem som har äganderätten till informationen samt vem som har ansvaret över att den är korrekt. Att implementeringskostnaden och designfasen blir dyrare är också ett problem med BIM. BIM kan användas för visualisering med 3D-modeller i kollisionskontroller och samgranskning i möten, arbetsberedningar och på byggarbetsplatsen. En APD-plan kan även skrivas ut från 3D-modellen för att visualisera byggarbetsplatsen. Tidsplanering och animationer med 4D skulle också kunna användas till visualisering i möten, arbetsberedningar och på byggarbetsplatsen. Studien visar att mängd- och kostnadsberäkningar med 5D endast stäms av i produktionsfasen och att programmen inte behövs i produktionsfasen. RFID-taggar kan användas på byggarbetsplatsen för logistikplanering och för att spåra material.5Fältkontroller kan vara användbart för att verifiera att ett arbete utförts exakt enligt 3D-modellens koordineringsdata. Handdatorer kan användas för att få ut tekniken för BIM på byggarbetsplatsen vilket möjliggör för en bättre förståelse för komplexa arbetsuppgifter för yrkesarbetarna. En BIM samordnare som förstår processen att arbeta med BIM och som kan överbrygga kommunikationssvårigheter mellan användarna och teknikutvecklingsgruppen är en mycket viktig aktör för ett framgångsrikt införande av BIM i ett projekt.Studien visar också att fokus bör ligga på hur man utnyttjar tekniken med fokus på nytta och användbarhet. De arbetsuppgifter som BIM skulle kunna användas till i produktionsfasen måste vara användbara och tillgodose användarnas krav och behov. Processen med att använda 3D-modeller, tidsplanering och animationer med 4D, RFID-taggar, fältkontroller och handdatorer måste därför studeras noggrant för att hitta hur tekniken kan tillämpas på byggarbetsplatsen, i möten, i arbetsberedningar samt hur den skulle kunna förbättra dagliga aktiviteter och arbetsuppgifter. Om användarnas krav är uppfyllda kommer tekniken att accepteras av både användaren och organisationen. Ytterligare forskning bör därför ligga på hur 3D-modeller, tidsplanering och animationer med 4D, RFID-taggar, fältkontroller och handdatorer kan vara användbara i produktionsfasen. Dessa tekniker bör sedan testas på ett verkligt projekt för att undersöka hur processerna för BIM skulle kunna vara användbara på byggarbetsplatsen, i möten och arbetsberedningar. Ytterligare forskning bör också göras på hur länder som Norge, Finland och USA har använt BIM i produktionsfasen i väg- och anläggningsprojekt.

Kreativitet är en förmåga som Försvarsmakten önskar att militär personal behärskar och använder. Samtidigt saknas en tydlig beskrivning av vad militär kreativitet är, hur det ska tolkas och om det påverkas av yttre påverkansfaktorer. Trots vikten av att officerare ska kunna behärska kreativitet i en militär kontext, återfinns det inte en entydig sammanhållen definition av begreppet att förhålla sig till. Syftet med denna studie var att bidra till en djupare förståelse för militär kreativitet och de drivkrafter som påverkar kreativiteten i en militär kontext. De två frågeställningar som ligger till grund för studien var: Hur tolkas kreativitet i en militär kontext av yrkesofficerare i Försvarsmakten? Vilka drivkrafter hämmar alternativt stimulerar kreativitet i en militär kontext hos den enskilde yrkesofficeren? Frågeställningarna undersöktes genom intervjuer med yrkesofficerare i Försvarsmakten och analyserades i enlighet med en Grounded Theory-ansats. Studiens resultat visar att det finns en militär kreativitet som uppstår då militär personal befinner sig i en militär kontext och ständigt tänker nytt. Mer specifikt kan denna militära kreativitet definieras som: när militär personal på ett nytt och nyttigt eller generativt sätt skapar progression i en militär kontext. Denna studie bidrar således med att belysa progression som en viktig utgångspunkt för förståelsen av militär kreativitet. Studien visar också att den organisatoriska miljön har en central betydelse för den militära kreativiteten eftersom den stimulerar eller hämmar den militära personalen i sitt utövande. Studiens resultat pekar särskilt på att förekomsten av negativ korrigering, eller bestraffning, inom Försvarsmakten har en påtagligt hämmande effekt på militär kreativitet. / Creativity is an ability that the Swedish Armed Forces want their military personnel to master and use. At the same time, there is no clear description of what military creativity is, how it should be interpreted and whether it is influenced by external influencing factors. Despite the importance of officers being able to master creativity in a military context, there is no unambiguously coherent definition of the term to relate to. The purpose of this study was to contribute to a better understanding of military creativity and the driving forces that influence creativity in a military context. The two questions that form the basis of the study were: How is creativity interpreted in a military context by professional officers in the Armed Forces? What driving forces inhibit or stimulate creativity in a military context of the individual professional officer? The issues were examined through interviews with professional officers in the Swedish Armed Forces and analyzed in accordance with a Grounded Theory approach. The results of the study show that there is a military creativity that arises when military personnel are in a military context and constantly think new. More specifically, this military creativity can be defined as: when military personnel in a new and useful or generative way create progression in a military context. This study thus helps to shed light on progression as an important starting point for the understanding of military creativity. The study also shows that the organizational environment is central to military creativity because it stimulates or inhibits military personnel in their practice. The results of the study indicate in particular that the presence of negative correction, or punishment, within the Swedish Armed Forces has a significant inhibiting effect on military creativity.

<p>Low angle grain boundary (LAGB) mobility is an essential parameter for developing the analytical models that describe the kinetics of recovery and predict the nucleation of recrystallized grains. The thesis is aimed at the molecular dynamics (MD) simulations study of LAGB mobility determination in pure Al and Al-Mg alloys. All the previous experimental studies reported that the presence of several defects, such as solutes and dislocations, retard the boundary motion and provide lower mobility. However, very few studies have been conducted in MD simulation to capture the interactions of those defects with the migrating grain boundary. This thesis is focused on providing complete understanding of LAGB determination along with a comprehensive explanation of solute and dislocation retarding effects on boundary motion.</p> <p>The LAGB mobility in pure Al was computed from two different MD techniques as a function of temperature and misorientation. Within numerical uncertainties, both techniques provide the same magnitude of mobility at 300K for 7.785^o boundary and at 700K for 23.07^o boundary. It was observed that ADF method is not applicable to determine LAGB mobility at high temperature due to failure of order parameter computation. The MD derived activation energy is found to be approximately ten times lower than the experimental observations.</p> <p>A strong solute pinning effect on boundary motion was observed at all misorientations and solute concentrations studied in Al-Mg alloys. An approximate linear relationship is found between the restraining force and the solute concentration in a distributed solute approach. In addition, the extrinsic dislocations are found to completely pin both 7.785^o and 23.07^o boundary motion at low driving forces in pure Al at 300K. The MD results do not reveal significant qualitative differences of the pinned boundary structure for the low and high angle boundaries and will be discussed in terms of the previous experimental observations.</p> / Doctor of Philosophy (PhD)

<div>Adsorbent technology is widely used in many industrial applications including waste heat recovery, water purification, and atmospheric revitalization in confined habitations. Astronauts depend on adsorbent-based systems to remove metabolic carbon dioxide (CO₂) from the cabin atmosphere; as NASA prepares for the journey to Mars, engineers are redesigning the adsorbent-based system for reduced weight and optimal efficiency. These efforts hinge upon the development of accurate, predictive models, as simulations are increasingly relied upon to save cost and time over the traditional design-build-test approach. Engineers rely on simplified models to reduce computational cost and enable parametric optimizations. Amongst these simplified models is the axially dispersed plug-flow model for predicting the adsorbate concentration during flow through an adsorbent bed. This model is ubiquitously used in designing fixed-bed adsorption systems. The current work aims to improve the accuracy of the axially dispersed plug-flow model because of its wide-spread use. This dissertation identifies the critical model inputs that drive the overall uncertainty in important output quantities then systematically improves the measurement and prediction of these input parameters. Limitations of the axially dispersed plug-flow model are also discussed, and recommendations made for identifying failure of the plug-flow assumption.</div><div><br></div><div>An uncertainty and sensitivity analysis of an axially disperse plug-flow model is first presented. Upper and lower uncertainty bounds for each of the model inputs are found by comparing empirical correlations against experimental data from the literature. Model uncertainty is then investigated by independently varying each model input between its individual upper and lower uncertainty bounds then observing the relative change in predicted effluent concentration and temperature (<i>e.g.</i>, breakthrough time, bed capacity, and effluent temperature). This analysis showed that the LDF mass transfer coefficient is the largest source of uncertainty. Furthermore, the uncertainty analysis reveals that ignoring the effect of wall-channeling on apparent axial dispersion can cause significant error in the predicted breakthrough times of small-diameter beds.</div><div><br></div><div>In addition to LDF mass transfer coefficient and axial-dispersion, equilibrium isotherms are known to be strong lever arms and a potentially dominant source of model error. As such, detailed analysis of the equilibrium adsorption isotherms for zeolite 13X was conducted to improve the fidelity of CO₂ and H₂O on equilibrium isotherms compared to extant data. These two adsorbent/adsorbate pairs are of great interest as NASA plans to use zeolite 13X in the next generation atmospheric revitalization system. Equilibrium isotherms describe a sorbent’s maximum capacity at a given temperature and adsorbate (<i>e.g.</i>, CO₂ or H₂O) partial pressure. New isotherm data from NASA Ames Research Center and NASA Marshall Space Flight Center for CO₂ and H₂O adsorption on zeolite 13X are presented. These measurements were carefully collected to eliminate sources of bias in previous data from the literature, where incomplete activation resulted in a reduced capacity. Several models are fit to the new equilibrium isotherm data and recommendations of the best model fit are made. The best-fit isotherm models from this analysis are used in all subsequent modeling efforts discussed in this dissertation.</div><div><br></div><div>The last two chapters examine the limitations of the axially disperse plug-flow model for predicting breakthrough in confined geometries. When a bed of pellets is confined in a rigid container, packing heterogeneities near the wall lead to faster flow around the periphery of the bed (<i>i.e.</i>, wall channeling). Wall-channeling effects have long been considered negligible for beds which hold more than 20 pellets across; however, the present work shows that neglecting wall-channeling effects on dispersion can yield significant errors in model predictions. There is a fundamental gap in understanding the mechanisms which control wall-channeling driven dispersion. Furthermore, there is currently no way to predict wall channeling effects a priori or even to identify what systems will be impacted by it. This dissertation aims to fill this gap using both experimental measurements and simulations to identify mechanisms which cause the plug-flow assumption to fail.</div><div><br></div><div>First, experimental evidence of wall-channeling in beds, even at large bed-to-pellet diameter ratios (<i>d</i>_bed/<i>d</i>_p=48) is presented. These experiments are then used to validate a method for accurately extracting mass transfer coefficients from data affected by significant wall channeling. The relative magnitudes of wall-channeling effects are shown to be a function of the adsorption/adsorbate pair and geometric confinement (<i>i.e.</i>, bed size). Ultimately, the axially disperse plug-flow model fails to capture the physics of breakthrough when nonplug-flow conditions prevail in the bed.</div><div><br></div><div>The final chapter of this dissertation develops a two-dimensional (2-D) adsorption model to examine the interplay of wall-channeling and adsorption kinetics and the adsorbent equilibrium capacity on breakthrough in confined geometries. The 2-D model incorporates the effect of radial variations in porosity on the velocity profile and is shown to accurately capture the effect of wall-channeling on adsorption behavior. The 2-D model is validated against experimental data, and then used to investigate whether capacity or adsorption kinetics cause certain adsorbates to exhibit more significant radial variations in concentration compared than others. This work explains channeling effects can vary for different adsorbate and/or adsorbent pairs—even under otherwise identical conditions—and highlights the importance of considering adsorption kinetics in addition to the traditional <i>d</i>_bed/<i>d</i>_p criteria.</div><div><br></div><div>This dissertation investigates key gaps in our understanding of fixed-bed adsorption. It will deliver insight into how these missing pieces impact the accuracy of predictive models and provide a means for reconciling these errors. The culmination of this work will be an accurate, predictive model that assists in the simulation-based design of the next-generation atmospheric revitalization system for humans’ journey to Mars.</div>

This diploma thesis deals with the different possible calculations of crack path. Specifically, it focuses on criteria based on maximum tangential stress, minimal strain energy density, crack tip displacement, and local symmetry. These criteria are used for calculations in ANSYS software to estimate possible crack paths on four simple structures. The thesis also contains the codes created in ANSYS. Using these, the crack trajectory of a given structure can be calculated by any of the four criteria described.