Cryogenic propellants are going to be the cornerstone for effective future human space exploration. These propellants need to be stored and maintained at really low temperatures for a long duration. Accurate phase change modeling is necessary for characterizing the thermal state of future cryogenic propellant tanks and for designing systems to alleviate the self pressurization problem. Better understanding about how to properly store and manage cryogenic propellants would help greatly with In-Situ Resource Utilization (ISRU) strategies for future missions to Mars and further. Predicting the fluid flow, heat transfer, and phase change mass transfer in long term cryogenic storage using CFD models is greatly affected by our understanding of the accommodation coefficient. The kinetically limited phase change model governed by the Hertz-Knudsen-Schrage equation is the model of choice for such calculations. The value of the accommodation coefficient required for the model is unknown for cryogenic propellants. Even in the case of water, the value of the accommodation coefficient has been found to vary over three orders of magnitude based on 80 years of measurements. Experiments specifically built to study accommodation coefficient are needed to estimate the value of the accommodation coefficient and understand some of the uncertainties surrounding these models. <div><br></div><div>Two phase change models, viz. the thermally limited and the kinetically limited phase change model are implemented in OpenFOAM. Different approaches to implement the Hertz-Knudsen-Schrage equation in a sharp interface conjugate heat transfer solver are studied. Evaporation and condensation calculations for a liquid hydrogen meniscus inside an aluminum container are compared with experimental measurements. The effect of accommodation coefficient on phase change is then studied with the kinetically limited model by comparing with the thermally limited model and the experimental measurements. The uncertainties associated with the temperature and pressure measurements in the experiment are quantified to show their effect on computational predictions. Since cryogenic propellants are perfectly wetting fluids, modeling the thin-film region close to the contact line leads to a multi-scale computational problem. However, the phase change contribution from the thin-film region is approximated in these computations to show the importance of modeling the contact line region accurately to adequately capture the small local thermodynamics in that region.</div>

Organisationer genomgår förändringar av olika slag, av olika anledningar där ledarskap är grunden för att föra en förändringsprocess framåt. Forskare har framtagit ledarskapsmodeller som belyser hur en ledare ska anamma sin roll utifrån ett ledarskapsperspektiv. Det finns därför en viss avsaknad av medarbetarnas perspektiv för att förstå hur ledare ska föra organisationsförändringar framåt. Denna studie undersöker därmed medarbetares förväntningar på ledarskap under organisationsförändringar. Studien utgår från en induktiv ansats med en fallstudiedesign, där datainsamling gjorts via kvalitativa intervjuer med sju medarbetare inom dagligvarubranschen. Datan har kodats och framställer fyra huvudkategorier av faktorer som medarbetare förväntar sig på ledarskap under organisationsförändringar, vilka är: kommunikation, mottaglighet, återkoppling samt förändringsbenägenhet. Medarbetare förväntar sig, vid organisationsförändringar, en ledare som kommunicerar väl, är mottaglig för medarbetarna genom delaktighet i diskussioner, har förmågan att ge samt ta emot feedback och som därmed är förändringsbenägen i förhållande till den givna situationen. Resultatet kan vidare användas i framtida forskning och studeras på ytterligare organisationer och branscher för att öka generaliserbarheten. / Organizations undergo changes of various kinds for various reasons, where leadership is the basis for moving a change process forward. Researchers have developed leadership models that highlight how leaders should embrace their role based on a leadership perspective. There is thus a lack of the employees' perspective to understand how leaders should bring organizational change forward. This study therefore examines employees' expectations of leadership during organizational change. The study is based on an inductive approach through a case study, where data collection was done via qualitative interviews with seven employees in the grocery industry. The data has been coded and describes four main categories of factors that employees expect from leadership during organizational changes, which are: communication, receptivity, feedback and propensity to change. Employees expect, in the event of organizational changes, a leader who communicates well, is receptive to the employees through participation in discussions, has the ability to give and receive feedback and who is thus prone to change in relation to the given situation. The result can further be used in future research and studied at additional organizations and industries to increase generalizability.

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Time, the one educational resource educators desire most, is so often in short supply in America 's schools. The ability of the school administrator to schedule teachers' and students' time so that both groups can maximize opportunities for teaching and learning each day has become an essential skill. Changing the structure of the school day to extend learning opportunities requires that administrators, teachers, and students have a firm commitment and clear understanding of the educational resources and processes of time. Successful practices regarding the use of time include: (a) careful planning and design, (b) adequate staff preparation and training, (c) effective use of extended time, and (d) a focus on equal access for students to multiple learning opportunities. Schools are under enormous pressure to show, through improved test scores, that they are providing every student with a thorough and efficient education. A review of the literature on alternative scheduling practices that use specified and structured blocks of learning time, focuses, overwhelmingly, on high school alternative scheduling models. However, there is a paucity of current research on the effects of alternative scheduling practices on elementary school cultures even though the elements of one particular method, parallel block scheduling, have been employed for over 30 years in elementary schools. This lack of research points to the necessity of exploring the benefits of alternative scheduling practices for delivery of instruction as well as changes in elementary school scheduling since the implementation of the No Child Left Behind mandate. / Ed. D.

The purpose of this study was to describe the needs and concerns regarding the Virginia Credentialing Initiative (VCI) of career and technical education (CTE) stakeholders in rural southwestern Virginia. These stakeholders included central office CTE administrators, high school principals, guidance counselors, and high school CTE teachers. The Stages of Concern Questionnaire (George, Hall, & Stiegelbauer, 2008) was sent to 355 participants with 260 responding for a return rate of 73%. All of the respondents were employed in Superintendents' Region Seven. There are seven Stages of Concern: 0 Unconcerned, 1 Informational, 2 Personal, 3 Management, 4 Consequence, 5 Collaboration, and 6 Refocusing. Results revealed that when categorized by occupational areas, central office CTE administrators and teachers had primary concerns that ranged from Unconcerned to Personal. Guidance counselors had primary concerns that ranged from Unconcerned to Informational. High school principals had primary concerns that ranged from Unconcerned to Personal. All groups had lowest concern levels at the Consequence and Refocusing stages. Results for each group varied slightly when the number of years of experience was used as a reporting category. The primary level of concern was at the Unconcerned stage for each group when the respondents had 5 or fewer years of experience. CTE teacher groups were also categorized by subject area as those with long-standing licensing history (cosmetology, nursing, welding) and those newer to credentialing (agriculture, business, family and consumer sciences, marketing). The fields of nursing and welding had primary concerns at the Unconcerned level, while those in the agriculture, business, cosmetology, family and consumer sciences, and marketing subject areas peaked at the Personal level. Further research is recommended in relation to CTE stakeholder concerns and the implementation and use of the VCI. The implementation of new state legislation will affect CTE stakeholders as they adapt to the new graduation requirements for students pursuing a standard diploma. It is also recommended that qualitative research be conducted to ascertain specific avenues for addressing stakeholder needs and concerns, such as professional development. / Ed. D.

Syfte:                              Syftet med studien är att analysera hur förändringsmottagare upplever att ledningens kommunikation inför organisationella förändringar påverkar dem för att få en beredskap inför förändringen.   Metod:                               Studien är en kvalitativ fallstudie med en abduktiv ansats, där den empiriska datainsamlingen gjorts genom intervjuer med anställda på ett företag i telekombranschen. En analys av insamlad data genomfördes genom en tematisk analys.   Resultat och slutsats:        Kommunikation inverkar på förändringsmottagarnas beredskap från sändarsidan, men effekten av denna dämpas på mottagarsidan av ett filter bestående av två faktorer, avtrubbning och påverkan på förändringsmottagarna.                                                                                      Förändringsmottagarna motsätter sig eller upplever en likgiltighet gentemot organisatoriska förändringar om kommunikationen upplevs som knapphändig eller är otydlig. Likaså påverkar bristen på möjligheter att återkoppla till ledningen för att skapa klargöranden, mottagarna i negativ riktning. Studiens bidrag:               Ge en djupare förståelse och kunskap i             kommunikationens betydelse för att skapa beredskap till förändring, och på så vis öka möjligheterna att genomdriva lyckosamma förändringsarbeten.   Förslag på vidare forskning:                          Att undersöka de faktorer som skapar avtrubbning till förändring hos förändringsmottagaren och hur dessa kan komma att undvikas.

L'effetto dei gas serra sul cambiamento climatico ha portato molti esperti a considerare la riduzione delle emissioni di gas serra come strategia per il riscaldamento globale. In particolare tale fenomeno è causato dall’anidride carbonica (CO2), metano (CH4) e il protossido di azoto (N2O). E 'ampiamente accettato che la principale fonte antropica di gas a effetto serra (tranne CO2) è dovuta alle attività agricole. Lo scopo di questo studio è quello di definire concetti e strumenti per facilitare il settore agricolo a ridurre le emissioni di gas serra. In particolare, abbiamo posto la nostra attenzione ai sistemi di misurazione delle emissioni dal suolo, testando un nuovo sistema (SASSFlux) e le sue caratteristiche a confronto con due strumenti ampiamente utilizzati (Bruel & Kjaer e gascromatografia). Inoltre abbiamo testato due modelli di simulazione (DNDC e SPACSYS) valutando i dati simulati e quelli misurati su un esperimento effettuato su lisimetri. In fine abbiamo applicato le conoscenze acquisite in pieno campo per la valutazione delle emissioni di CO2 e N2O con diversi concimi e lavorazione del terreno. La tesi si propone di fornire una visione completa dei diversi aspetti da affrontare nella valutazione delle emissioni di gas serra provenienti da diversi scenari di gestione agricola. / The effect of greenhouse gases (GHG) on climate change led many experts to consider the reduction of GHGs emissions as a crucial strategy to tackle the predicted global warming. In particular, atmospheric warming is caused mainly by carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). It is widely accepted that the main anthropogenic source of GHG (except CO2) is due to agriculture activities. The purpose of this study was to help define concepts and tools to facilitate agricultural sector to reduce greenhouse gas emissions. In particular we based our focus on measuring systems for CO2 emissions, testing the performance of novel system (SASSFlux) and its features in different condition with two widely used instruments (Bruel&Kjaer and gas chromatography). Moreover we testing two process-based models, DNDC and SPACSYS, evaluating their performance and the agreement between simulated and measured data on a experiment carried out on lysimeters. At the end we applied all the knowledge acquired on a field experiment evaluating CO2 and N2O emissions from different organic and mineral fertilizers and tillage. The complete thesis aims to provide a comprehensive view of the different aspects to be addressed in the assessment of GHG emissions from different scenarios of agricultural management.

Bakgrund: De senaste åren har cirkulär ekonomi fått uppmärksamhet och även funnits på den politiska agendan inom Sverige och Europa, tack vare en ökad klimatinsikt. Cirkulär ekonomi syftar på en sluten värdekedja som bör ersätta den linjära värdekedjan då den slutna kedjan fokuserar på hållbarhet. Den linjära värdekedjan har sedan den industriella revolutionen orsakat ett ”slit och släng samhälle”, detta ska den cirkulära ekonomin motverka. Klädbranschen är en marknad som producerar mycket avfall vilket gör den cirkulära ekonomin till ett mer hållbart alternativ. Trots fördelarna med det cirkulära så finns det problematik för företag kring förändringen. För att övervinna problematiken blir förståelsen kring de primära drivkrafterna viktiga faktorer. Detta för att se hur utvecklingen mot ett cirkulärt arbete fortskrider. Syfte: Uppsatsens syfte är att öka förståelse kring vilka drivkrafter som är de mest primära som leder till en organisatorisk förändring mot en cirkulär ekonomi. Metod: Detta är en kvalitativ studie som utgår ifrån ett hermeneutiskt perspektiv som ska öka förståelsen utifrån de intervjuade organisationernas uppfattning. Empirin formades utifrån semistrukturerade intervjuer med tre organisationer genom en Små-N- Studie. Studien startades med en litteraturstudie som formade uppsatsens inriktning och teorikapitel, ansatsen inom uppsatsen är abduktiv. Slutsats: Inom studien sågs det att de drivkrafter som berör både interna och externa faktorer har en större inverkan. Den mest primära interna drivkraften anses vara ledningen för att deras värderingar formar företag och de förändringarna som beslutas genomföra. Den mest primära externa drivkraften anses vara att förstärka företagens konkurrenskraft. Detta relaterar till att överleva i en värld som förändras och att anpassa sig utefter de förutsättning som kommer med en cirkulär ekonomi, ifrån marknaden och andra intressenter. Interna drivkrafter tenderar även till att leda till starkare hållbarhetsarbeten på grund av att sådana drivkrafter leder mer proaktiva förändringar. De externa drivkrafterna tenderar att orsaka mer reaktiva förändringar. / Background: Circular economy have during the last years gotten attention and been on the political agenda within Sweden and Europe due to an increased climate awareness. The circular economy refers to a closed value chain, which should replace the linear value chain due to its sustainability focus. The linear chain has since the industrial revolution caused a “tear and toss society”, which the circular economy is supposed to counteract. The fashion branch is today a market that produces a lot of waste, which would make the circular economy a more sustainable option. Despite the circular economy’s advantages there is still some problems regarding the companies’ changing processes. Therefore, the increased understanding of the primary driving forces regarding the development towards circular working methods becomes an important factor. Purpose: The purpose is to increase the understandings about which drivers that are the most primary for organizations that leads a change towards a circular economy. Method: The thesis is built on a qualitative method based on a hermeneutist perspective, which aims to increase understandings regarding drivers to a circular economy. The empiric came from semi-structured interviews with three organizations through a Small-N-Study. The thesis was based on a literature study that formed the essay’s alignment and theoretical framework. The thesis has an abductive approach. Conclusion: Within the study the drivers that is affected by both internal and external factors is shown having a bigger impact. The most primary internal driver is seen being the management and the founders due to their values which forms the company and the decisions about which changes to perform. The most primary external driver is to enhance the company’s competitiveness. The competitiveness relates to survival in a changeable world and to adjust to the conditions that comes with a circular economy, the market and other stakeholders. Internal drivers tend to lead stronger sustainability focus because of that those drivers causes more proactive changes. The external drivers tend to cause more reactive changes.

Made available in DSpace on 2016-04-25T16:44:45Z (GMT). No. of bitstreams: 1 Eliza Albuquerque da Silva.pdf: 788447 bytes, checksum: af0398d70b9a30695b24e4dab66e13a4 (MD5) Previous issue date: 2015-09-24 / In an increasingly more dynamic environment, doubts have been cast on the validity of the existing models of organizational change and its implementation, as they assume a return to stability. In this regard, it is relevant to review the main theories related to the theme to establish the basis of a proposed approach that will take this increased dynamic feature into account, as well as check the validity of this model by conducting a research with companies working in Brazil. For that, the existing dialog between organizations seen as change flows and the implementation of sporadic changes was explored. The latter was considered a mechanism for directing the continuity of changes. However, the theory points out the importance of implementing such changes in organizations that have favorable characteristics to adaptability and flexibility. Hence this study proposes an approach for the issue of organizational change in dynamic environments based on the pillars of robust process to direct sporadic changes and the development of favorable organizational characteristics. This approach may allow for organizations to be more successful in the results of their change initiatives, besides contributing to the maintenance of their competitive places, and therefore in keeping with their financial results. This approach's validity was tested through a quantitative research applied to 211 companies of various sizes and sectors in Brazil. Research results confirmed that the more robust the change processes and the more favorable organizational characteristics are shown, the better are the results achieved through such initiatives, according to the respondents' perception. The study also made it possible to learn that besides the correlation between processes and organizational characteristics, these aspects are also correlated with the perception of improved financial results / Em um ambiente cada vez mais dinâmico, tem se questionado a validade dos modelos existentes para a condução de mudança organizacional, uma vez que pressupõem retorno à estabilidade. Neste sentido considera-se relevante a revisão das principais teorias relacionadas ao tema para fundamentar a proposição de abordagem que dê conta deste maior dinamismo, bem como verificar a validade deste modelo a partir de uma pesquisa junto às empresas atuantes no Brasil. Para tal explorou-se o diálogo existente entre as organizações vistas como fluxos de mudanças e o empreendimento de mudanças episódicas, sendo este último considerado como um mecanismo para direcionamento da continuidade das mudanças. Contudo a teoria aponta a importância do empreendimento dessas mudanças em organizações que demonstrem características favoráveis à adaptabilidade e flexibilidade. Por isso o estudo propõe uma abordagem para questão da mudança organizacional em ambientes dinâmicos baseada nos pilares de processos robustos para a condução de mudanças episódicas e de desenvolvimento de características organizacionais favoráveis. Acredita-se que essa abordagem permite que as organizações tenham mais êxito no resultado das suas iniciativas de mudança, além de contribuir para a manutenção de suas posições competitivas, estando, portanto, correlacionada com seus resultados financeiros. Para testar a validade dessa abordagem foi aplicada uma pesquisa quantitativa junto a 211 empresas de diversos portes e setores do Brasil. Os resultados de pesquisas comprovaram que quanto mais robustos os processos de mudanças e mais características organizacionais favoráveis são demonstradas, melhores são os resultados obtidos com essas iniciativas, segundo a percepção dos respondentes. No estudo também foi possível verificar que além de processos e características organizacionais estarem correlacionados, essas dimensões também estão correlacionadas com a percepção de melhorias nos resultados financeiros