Segui questo link per vedere altri tipi di pubblicazioni sul tema: Hexaco model.

Tesi sul tema "Hexaco model"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili

Scegli il tipo di fonte:

Vedi i top-27 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Hexaco model".

Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.

Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.

Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.

1

Zietlow, Kim J. "Socio-demographic and psychological determinants of water conservation behavior". Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17425.

Testo completo
Abstract (sommario):
Wasser ist eine der wichtigsten Ressourcen. Jedoch schätzt man, dass sich das globale Wasserdefizit schon im Jahr 2030 auf ca. 40 Prozent belaufen wird. Klimawandel, veränderte Lebensweisen, und Bevölkerungswachstum verstärken das Nachfrage-Angebot-Defizit. Als Konsequenz leiden immer mehr Regionen unter Wasserknappheit. Eine reduzierte Wassernachfrage bedingt durch verstärktes Wassersparen kann das Problem verringern. Das Ziel dieser Dissertation ist es daher, zu einem besseren Verständnis der sozio-demographischen und psychologischen Determinanten von Wassersparverhalten beizutragen. Basierend auf drei Datensätzen aus Deutschland und Jordanien wurden die verschiedenen Facetten von Wassersparverhalten und deren Determinanten beleuchtet. Das Verhältnis zwischen Wassersparen und Umwelteinstellung, einem latenten Konstrukt, das kooperative, prosoziale und sogar moralische Tendenzen widerspiegelt, wurde konzeptionell untersucht. Zusätzlich wurde Wassersparen in Deutschland als ein Repräsentant für moralisches Verhalten verwendet. In diesem Zusammenhang wurden Umwelteinstellung und der Persönlichkeitsfaktor Ehrlichkeit-Bescheidenheit auf ihr Vermögen hin verglichen, moralisches Verhalten vorherzusehen. Eine ausführliche Analyse zur Bewertung einer Kampagne zur Förderung des Wassersparbewusstseins hat detaillierte Informationen zu ihren tatsächlichen Effekten gezeigt. Eine weitere Analyse hat sich auf die Determinanten von Wassersparverhalten in Jordanien konzentriert. Die Ergebnisse zeigen, dass Wassersparverhalten nicht durch Alter, Bildungsgrad und Einkommen beeinflusst wird, sondern eher durch die Ausprägung der Umwelteinstellung. Diese Dissertation liefert wertvolle Informationen für Forscher und Politiker. Die detaillierte Untersuchung von verschiedenen Wasserspardeterminanten birgt großes Potenzial für ein verbessertes Wassermanagement.
Water is one of the most important resources. However, the global water deficit was estimated to reach about 40% by 2030. Climate change, changing lifestyles, and population growth increase the supply and demand gap further. As a consequence, more and more regions experience water scarcity. In that context, reduced household water demand due to enhanced water conservation could alleviate the problem or, at least, reduce the pressure on water resources. Thus, this thesis aims to contribute to a better understanding of the socio-demographic and psychological determinants of water conservation behavior. Based on three distinct datasets from Germany and Jordan, the manifold facets of water conservation and its determinants were examined. From a conceptual perspective, the relationship between water conservation and environmental attitude, a latent construct representing cooperative, prosocial, and even moral tendencies, were investigated. Furthermore, water conservation in Germany was used as a proxy for moral behavior. In that respect, environmental attitude and the personality factor Honesty-Humility were compared in order to determine, which factor constitutes the better predictor of moral behavior. Using original data from Jordan, a comprehensive impact evaluation of a water conservation awareness campaign revealed detailed information on its actual effects. Another analysis focused on a wide variety of water conservation determinants in Jordan. The results indicate that water conservation does not differ with respect to age, education, and income, but rather with different levels of environmental attitude. This thesis provides valuable information for researchers and policy makers alike. The detailed examination of various water conservation determinants offer a great potential for an improved management of household water demand.
Gli stili APA, Harvard, Vancouver, ISO e altri
2

Fouche, Erica. "The relationships between engagement, burnout and performance in an e-commerce retail company". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96792.

Testo completo
Abstract (sommario):
Thesis (MComm)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: It is the role of the Industrial Psychologist and the Human Resources function within a company to contribute positively to an organisation’s competitive advantage. Human capital should be viewed and managed as a critical success factor within this context. The probability of attaining success over competitors could be addressed through focussing on the impact of employee performance on competitive advantage. With reference to the organisational life cycle, the e-commerce industry in South Africa seems to be in its infancy. It is in this stage when attaining high levels of performance from employees is of critical importance. In this lies the key for building and growing a competitive advantage that would set one organisation apart from the other – where one organisation would survive the infancy stage and another would drown in the quest to match the demands posed by the relevant industry and its customers. There is minimal Industrial or Organisational Psychology research that has tested hypotheses in the e-commerce industry. This contributed to the decision to implement this research in the e-commerce industry. The e-commerce industry is growing rapidly, and performance therefore is a key factor for success in any e-commerce company in South Africa. The focus of this study was to review the Job Demands Resources model (JD-R model) within the e-commerce retail industry in South Africa in order to add to the knowledge base regarding human behaviour at work, with specific reference to engagement, burnout and performance. The research question of the study was formulated regarding which “state of wellbeing” would increase performance. The JD-R model makes provision for evaluating this question in a structured manner. The JD-R model indicates that performance is influenced by work engagement/burnout (wellbeing). It also indicates that there are certain job demands, job resources and personal resources that will influence wellbeing. The study was facilitated through the use of an ex post facto correlational research design. A sample of 117 workers was chosen from the e-commerce retail industry to participate in the study. Participation was voluntary, the data was collected specifically for the purpose of this study, and all responses were treated confidentially. The measurements that were used included key performance indicators (KPIs), the Utrecht Work Engagement Scale (UWES), the Maslach Burnout Inventory – General Survey (MBI-GS), the Job Characteristics Scale, and the HEXACO model. The literature review formed a logical argument that culminated in a theoretical Stellenbosch University https://scholar.sun.ac.za iii model as well as a set of hypotheses with reference to the various dimensions in the JD-R model. The results showed that: a) Engagement has a significant positive influence on performance. b) Job resources (advancement, personal growth and organisational support) have a significant positive influence on engagement. c) Job resources (advancement, personal growth and organisational support) have a significant negative influence on burnout. d) Personal resources (extraversion) have a significant negative influence on burnout. e) Personal resources (conscientiousness) have a significant positive influence on engagement. f) Personal resources (agreeableness) have a significant negative influence on burnout. The following hypotheses were not supported: a) Burnout has a significant negative influence on performance. b) Personal resources (extraversion) have a significant positive influence on engagement. c) Personal resources (emotionality) have a significant positive influence on engagement. d) Personal resources (emotionality) have a significant negative influence on burnout. e) Personal resources (conscientiousness) have a significant negative influence on burnout. f) Personal resources (agreeableness) have a significant positive influence on engagement. g) Job demands (job overload) have a significant negative influence on engagement. h) Job demands (job overload) have a significant positive influence on burnout. i) Job demands (job insecurity) have a significant negative influence on engagement. j) Job demands (job insecurity) have a significant positive influence on burnout. Attention was also paid to future research considerations, recommendations to the managers of employees and to the limitations of the study.
AFRIKAANSE OPSOMMING: Dit is die rol van die Bedryfsielkundige en die Menslike Hulpbronne funksie in maatskappye om 'n positiewe bydrae tot 'n organisasie se mededingende voordeel te maak. Menslike kapitaal moet beskou en bestuur word as ‘n kritiese sukses faktor in hierdie konteks. Die waarskynlikheid om sukses bo die kompetisie te behaal kan aangespreek word deur om fokus te plaas op die impak wat werknemersprestasie het op mededingings voordeel. Met verwysing na die organisatoriese lewenssiklus blyk die e-handelbedryf in Suid-Afrika om in sy beginstadium te wees. Dit is in hierdie stadium waar die bereiking van hoë vlakke van prestasie van werknemers van kritieke belang is. Hierin lê die sleutel vir die vordering en groei van 'n mededingende voordeel van een maatskappy bo ‘n ander - waar die een organisasie die beginstadium sou oorleef en die ander onder die druk van die versoeke/eise van die betrokke bedryf en sy kliënte sou swyk. Daar is ‘n beperkte hoeveelheid navorsing wat gevind kon word in die veld van Bedryfsielkunde wat hipoteses in die e-handelbedryf toets. Hierdie bevinding het bygedra tot die besluit om hierdie navorsingstudie oor die e-handelbedryf voort te sit. Die e-handelbedryf toon vinnige groei, en prestasie is dus tans 'n belangrike faktor vir sukses in enige e-handelmaatskappy in Suid-Afrika. Die fokus van hierdie navorsingstudie was om die “Job Demands Resources model (JD-R model)” in die e-kleinhandelbedryf in Suid-Afrika toe te pas om sodoende by te dra tot die huidige kennis beskikbaar ten opsigte van menslike gedrag by die werk, met spesifieke verwysing na werksbegeestering, uitbranding en prestasie. Die navorsingsvraag van die navorsingstudie is geformuleer rondom die aanname dat die "toestand van welsyn" prestasievlakke sal verhoog. Die primêre doel van die navorsingstudie was om deur middel van die toepassing van die JD-R model in die e-kleinhandelbedryf, by te dra tot die beskikbare kennis ten opsigte van menslike gedrag by die werk, met spesifieke verwysing na werksbetrokkenheid, uitbranding en prestasie. Die JD-R model maak op 'n gestruktureerde wyse voorsiening vir die evaluering van hierdie verhoudings. Die JD-R model dui aan dat prestasie beïnvloed word deur werksbetrokkenheid/uitbranding (welsyn). Dit dui ook dat daar sekere werksvereistes, werkshulpbronne en persoonlike hulpbronne is wat welstand beïnvloed. Stellenbosch University https://scholar.sun.ac.za v Die navorsingstudie is gefasiliteer deur die gebruik van 'n ex post facto korrelasie-ontwerp. 'n Steekproef van 117 werkers is uit die e-kleinhandelbedryf gekies om aan die studie deel te neem. Deelname was vrywillig, die data is spesifiek ingesamel vir die doel van hierdie navorsingstudie en alle data is as vertroulik hanteer. Die volgende metingsinstrumente is gebruik: kern prestasie aanwysers (KPA’s), die Utrecht Work Engagement Scale (UWES), die Maslach Burnout Inventory – General Survey (MBI-GS), die Job Characteristics Scale, en die HEXACO model. Die literatuuroorsig vorm 'n logiese argument wat lei tot 'n teoretiese model, sowel as 'n stel hipoteses met verwysing na die verskillende dimensies soos gevind in die JD-R model. Die resultate toon: a) Werksbetrokkenheid het ‘n beduidende positiewe invloed op prestasie. b) Werkshulpbronne (bevordering, persoonlike groei en organisatoriese ondersteuning) het ‘n beduidende positiewe invloed op werksbetrokkenheid. c) Werkshulpbronne (bevordering, persoonlike groei en organisatoriese ondersteuning) het ‘n beduidende negatiewe invloed op uitbranding. d) Persoonlike hulpbronne (ekstroversie) het ‘n beduidende negatiewe invloed op uitbranding. e) Persoonlike hulpbronne (pligsgetrouheid) het ‘n beduidende positiewe invloed op werksbetrokkenheid. f) Persoonlike hulpbronne (eenstemmigheid) het ‘n beduidende negatiewe invloed op uitbranding. Die volgende hipoteses was nie aanvaar nie: a) Uitbranding het ‘n beduidende negatiewe invloed op prestasie. b) Persoonlike hulpbronne (ekstroversie) het ‘n beduidende positiewe invloed op werksbetrokkenheid. c) Persoonlike hulpbronne (emosionaliteit) het ‘n beduidende positiewe invloed op werksbetrokkenheid. d) Persoonlike hulpbronne (emosionaliteit) het ‘n beduidende negatiewe invloed op uitbranding. e) Persoonlike hulpbronne (pligsgetrouheid) het ‘n beduidende negatiewe invloed op uitbranding. f) Persoonlike hulpbronne (eenstemmigheid) het ‘n beduidende positiewe invloed op werksbetrokkenheid. Stellenbosch University https://scholar.sun.ac.za vi g) Werksvereistes (oorlading) het ‘n beduidende negatiewe invloed op werksbetrokkenheid. h) Werksvereistes (oorlading) het ‘n beduidende positiewe invloed op uitbranding. i) Werksvereistes (werkonsekerheid) het ‘n beduidende negatiewe invloed op werksbetrokkenheid. j) Werksvereistes (werkonsekerheid) het ‘n beduidende positiewe invloed op uitbranding. Aandag is ook geskenk aan toekomstige navorsings oorwegings, aanbevelings aan die bestuurders van werknemers asook aan die beperkinge van die navorsinstudie.
Gli stili APA, Harvard, Vancouver, ISO e altri
3

McKay, Derek A. "A facet and domain-level analysis of two trait models of personality: Relationship with subjective well-being". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1498591744789927.

Testo completo
Gli stili APA, Harvard, Vancouver, ISO e altri
4

Mauduit, Marion. "Profils de personnalité et facteurs motivationnels mobilisés lors d'une réorientation vers les études de médecine après un parcours académique ou professionnel différent". Electronic Thesis or Diss., Rennes 2, 2024. http://www.theses.fr/2024REN20009.

Testo completo
Abstract (sommario):
Les étudiants « passerelle », qui se réorientent en médecine après un parcours académique etprofessionnel différent ont pour la première fois fait l’objet d’un travail qui vise à décrire leur profil sociodémographique, leurs caractéristiques psychologiques, et les facteurs motivationnels qui sous-tendent leur choix de réorientation vers les études de médecine. Au travers d’une étude qualitative basée sur 42 entretiens semi-dirigés, et d’une étudequantitative réalisée auprès de 718 étudiants en médecine des facultés de Rennes, Nantes, Angers, Tours, et Brest, ce travail de thèse nous montre tout d’abord que les étudiants « passerelle » ont un profil socio-démographique comparable à celui des étudiants en médecine français. Ils sont principalement motivés par un intérêt intrinsèque pour la médecine, etont des attentes plus élevées que les autres étudiants par rapport à la dimension humaine et altruiste du métier de médecin. Les attentes telles que le prestige et la reconnaissance sociale sont au second plan.Ils ont pour principaux traits de personnalité (modèle HEXACO) l’honnêteté-humilité et la conscienciosité, ce qui est aussi le cas des autres étudiants en médecine. Nos résultats montrent qu’ils sont plus extravertis, et qu’ils ont un score d’honnêteté-humilité plus élevé que les autres étudiants. Les valeurs les plus importantes pour eux sont axées vers la transcendance de soi, et l’ouverture au changement. Il semble que les valeurs d’affirmationde soi soient moins importantes pour eux que pour les autres étudiants. Nous avons mis en évidence deux profils de personnalité parmi les étudiants en médecine, dont un profil « altruisme et engagement élevé » qui se distingue par un niveau plus élevé d’honnêteté-humilité, de conscienciosité, d’agréabilité et d’extraversion, au sein duquel les étudiants « passerelle » qui n’avaient pas tenté le concours de la première année de médecine en post baccalauréat semblent être plus nombreux
Gateway-entry medical students bypass the traditional first-year selection process for medical school, gaining admission after completing a master’s degree, a PhD, or specific undergraduate degrees. Very little is known about these gateway medical students. This study aims at describing their socio-demographic profile, their personal psychological characteristics, and the motivational factors driving their shift towards medical studies, while also examining the personality traits that may differentiate them from their peers. Through a qualitative study based on 42 semi-structured interviews, and a quantitative study carried out on 718medical students from the faculties of Rennes, Nantes, Angers, Tours and Brest, this study reveals several key findings. Firstly, gateway students exhibit a sociodemographic profile similar to that of their French medical counterparts. They are primarily motivated byan inherent interest in medicine and hold greater expectations regarding the humanistic and altruistic facets of the medical profession compared to other students. While factorssuch as the prestige and social recognition associated with being a doctor also influence theirchoice, these are secondary considerations. Their main personality traits (HEXACO model) arehonesty-humility and conscientiousness. However, they tend to exhibit higher levels of extroversion and honesty-humility compared to their counterparts. Their core personal values emphasize selftranscendence and openness to change. Furthermore, our analysis identifies two distinct personality profiles among medical students, with a notable "high altruism and commitment" profile characterized by elevated levels of honesty-humility, conscientiousness, agreeableness, and extroversion. Interestingly, a higher proportion of gateway students (those who had not attempted the first-year medical entrance examination after completing high school) fall within this profile
Gli stili APA, Harvard, Vancouver, ISO e altri
5

Guo, Yixuan. "Hexapod Gait Planning and Obstacle Avoidance Algorithm". University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1461868607.

Testo completo
Gli stili APA, Harvard, Vancouver, ISO e altri
6

Zhang, Li. "Accuracy enhancement of a hexapod machine tool /". Essen : Vulkan-Verl, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?id=2864795&prov=M&dok_var=1&dok_ext=htm.

Testo completo
Gli stili APA, Harvard, Vancouver, ISO e altri
7

Rosano-Matchain, Hugo Leonardo. "Decentralised compliant control for hexapod robots : a stick insect based walking model". Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/2574.

Testo completo
Abstract (sommario):
This thesis aims to transfer knowledge from insect biology into a hexapod walking robot. The similarity of the robot model to the biological target allows the testing of hypotheses regarding control and behavioural strategies in the insect. Therefore, this thesis supports biorobotic research by demonstrating that robotic implementations are improved by using biological strategies and these models can be used to understand biological systems. Specifically, this thesis addresses two central problems in hexapod walking control: the single leg control mechanism and its control variables; and the different roles of the front, middle and hind legs that allow a decentralised architecture to co-ordinate complex behavioural tasks. To investigate these problems, behavioural studies on insect curve walking were combined with quantitative simulations. Behavioural experiments were designed to explore the control of turns of freely walking stick insects, Carausius morosus, toward a visual target. A program for insect tracking and kinematic analysis of observed motion was developed. The results demonstrate that the front legs are responsible for most of the body trajectory. Nonetheless, to replicate insect walking behaviour it is necessary for all legs to contribute with specific roles. Additionally, statistics on leg stepping show that middle and hind legs continuously influence each other. This cannot be explained by previous models that heavily depend on positive feedback controllers. After careful analysis, it was found that the hind legs could actively rotate the body while the middle legs move to the inside of the curve, tangentially to the body axis. The single leg controller is known to be independent from other legs but still capable of mechanical synchronisation. To explain this behaviour positive feedback controllers have been proposed. This mechanism works for the closed kinematic chain problem, but has complications when implemented in a dynamic model. Furthermore, neurophysiological data indicate that legs always respond to disturbances as a negative feedback controller. Additional experimental data presented herein indicates that legs continuously oppose forces created by other legs. This thesis proposes a model that has a velocity positive feedback control modulated via a subordination variable in cascade with a position negative feedback mechanism as the core controller. This allows legs to oppose external and internal forces without compromising inter-leg collaboration for walking. The single leg controller is implemented using a distributed artificial neural network. This network was trained with a wider range of movement to that so far found in the simulation model. The controller implemented with a plausible biological.
Gli stili APA, Harvard, Vancouver, ISO e altri
8

Custodio, Aline Ferrão. "Modelagem e simulação do processo de separação de oleo de soja-hexano por evaporação". [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266512.

Testo completo
Abstract (sommario):
Orientadores: Rubens Maciel Filho, Dailton de Freitas Rezende
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-04T02:31:08Z (GMT). No. of bitstreams: 1 Custodio_AlineFerrao_M.pdf: 1962631 bytes, checksum: 51b733d6a4d5cc5f583e63880f05a9eb (MD5) Previous issue date: 2003
Resumo: Até as duas primeiras décadas do século XX, a extração industrial de oleaginosas se fazia, exclusivamente pelo uso de prensas. As prensas, embora extraíssem um óleo de muito boa qualidade, deixavam resíduos no material sólido (torta) superiores, por exemplo a 5% para grãos como o de soja. Tais resíduos além de implicarem em perda de óleo, afetavam a qualidade da torta, que é também um dos produtos efluentes do extrator. A extração por solvente, por outro lado, é capaz de retirar o óleo, deixando resíduos inferiores a 1%. Após a extração, os sólidos são encaminhados ao dessolventizador e a micela (mistura óleo-solvente) ao sistema de destilação, composto por dois evaporadores em série e uma coluna de dessorção (stripping). A unidade de evaporação é uma das que mais demandam energia em uma planta de processamento. Assim, a modelagem matemática dinâmica deste processo com vistas à otimização do consumo energético e à avaliação do desempenho de políticas de controle torna-se um requisito decisivo para operação economicamente viável. O objetivo geral deste trabalho é desenvolver um modelo dinâmico efetuando análises de sensibilidade paramétrica para um evaporador típico da indústria de extração de óleos vegetais, visando a otimização deste processo, ou seja, a recuperação máxima de solvente e o consumo mínimo de energia. A fim de analisar as condições de operação do sistema, propôs-se um modelo matemático do sistema de evaporação com base no de TONELLI et al. (1990), consistindo em balanços mássicos global e de óleo e de balanço energético em torno do sistema de evaporação. O programa simulador foi construído em linguagem FORTRAN. Este programa, a partir de informações tais como temperatura, pressão e concentração de alimentação, assim como de quais são os componentes envolvidos, calcula propriedades termodinâmicas tais como temperaturas de ebulição, capacidades térmicas e entalpias de misturas. Desse modo, um mínimo de informações são requeridas, permitindo simulações rápidas do processo de evaporação. O programa computacional elaborado permitiu simulações rápidas e com baixos erros numéricos para o processo de evaporação do solvente em uma unidade de dessolventização do óleo após extração convencional. Este programa permitiu ainda avaliações de efeitos para os fatores influentes na evaporação. Considerando-se a intensidade das perturbações realizadas e o nível central dos fatores, o fator fração mássica de óleo na entrada foi o que apresentou o maior efeito. Já a velocidade de escoamento do vapor de água de aquecimento foi o fator com o menor efeito no teor de óleo da micela efluente
Abstract: Until the two first decades of century XX, the industrial extraction of oleaginosas were carried out exclusively by mechanical process. This process allow to extracted oil of very good quality, but it leads the left residues in the solid material (pie) to be very high, for example 5% for grains as of soy. Such residues besides implying in loss of oil, affected the quality of the pie, that is also one of the effluent products of the extractor. The extraction for solvent, on the other hand, is capable to remove the oil, leaving residues to be smaller (1%). After the extraction, the solids are directed to the dessolventizador and miscella (oil-solvent mixture) to the distillation system. Witch is composed by two evaporators in series and a stripping column. The unit of evaporation is one that demands for high energy consumption in a processing plant. Thus, the dynamic mathematical modeling of this process with sights to the reduction of the energy consumption and to the evaluation of the performance of control politics becomes a decisive requirement for economically viable operation. The general objective of this work is to develop a dynamic model of the process witch allow for parametric sensitivity analyze for a typical evaporator for the vegetal oil industry extraction. The aim is to have a tool for either process optimization or maximum recovery of solvent. The deterministic mathematical model is developed through mass and energy balance equation together with heat and mass transfer parameter correlations. The simulator was build up in FORTRAN. The software uses operational information as feed temperature, concentration and pressure witch allows for the calculation of the thermodynamic properties such as thermal temperatures of boiling, capacities and enthalpies of mixtures. In this way, a minimum of information is required, allowing fast simulations of the evaporation process. Through experimental design procedure applied to the deterministic model was possible to identify the main operational variables effects as well as the impact of the extraction array variables has on the process behaviors. The mass oil fraction in the feed was found to have the largest effect. The speed of the water vapor draining for the heating zone was the factor with the loweit effect in the oil miscella effluent
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
Gli stili APA, Harvard, Vancouver, ISO e altri
9

Morrone, Simone Ribeiro. "Determinação experimental do volume excesso de soluções de ciclohexano /2-Propanol, ciclohexano /2-Butanol, N-Hexano/2-Propanol, N-Hexano/2-Butanol a 298,15k e A 288,15K e aplicação do modelo eras". [s.n.], 1994. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267378.

Testo completo
Abstract (sommario):
Orientador: Artur Zaghini Francesconi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-07-19T19:55:37Z (GMT). No. of bitstreams: 1 Morrone_SimoneRibeiro_M.pdf: 2187661 bytes, checksum: f6de3136083125531a4343e725484084 (MD5) Previous issue date: 1994
Resumo: Os objetivos deste trabalho consistiram no levantamento de dados inéditos do volume excesso, por densitometria, de soluções alcano/alcanol e no teste do modelo de soluções ERAS. Os sistemas estudados foram ciclohexano/2-propanol, ciclohexano/2-butanol, n-hexano/2-propanol, n-hexano/2-butanol à pressão ambiente e às temperaturas de 288,15 K e 298,15 K. Todos os valores do volume excesso foram positivos, sendo o maior valor aproximadamente 0,6 cm3/mol encontrado para ciclohexano/2-butanol, a 298,15 K. As curvas volume excesso em função das frações molares dos alcanos possuem formas parabólicas para o ciclohexano e sigmóides para o n-hexano. Constatou-se que o volume excesso aumenta com: a temperatura, o comprimento da cadeia do alcanol e a esfericidade do alcano. o modelo ERAS, que, ao contrário de outras teorias de solução, responde bem não somente à energia livre de Gibbs em excesso, mas também a outras grandezas excesso, foi desenvolvido por Heintz para sistemas do tipo aicano/alcanol.A principal característica deste modelo é o cálculo simultâneo das grandezas excesso. Os resultados apresentados foram bons, chegando, algumas vezes, a valores bem próximos dos experimentais
Abstract: The aim of this work were to collect new data of the excess volume of alkane alkanol solutions, using a vibrating-tube densimeter, and to test the solution model ERAS. The systems studied were cyclohexane/2-propanol, cyclohexane/2-butanol, n-hexane/2-propanol, n-hexane/2-butanol at 288.15 K and 298.15 K and room pressure. Ali values of the excess volume were positive and the maximum was about 0.6 cm3/mol for the cyclohexane/2-butanol at 298.15 K. The curves excess volume versus mole fractions have parabolic form for systems containing cyclohexane and sigmoid form for the n-hexane systems. It was observed that the excess volume increased with: the temperature, the lenght of the alkanol chain and the sphere shape of the alkane. The ERAS model, regardless of other solution theories, does not present good results only for the excess Gibbs free energy, but also for any excess . property, was developed by Heintz for alkane/alkanol systems. The main feature of this model is the simultaneous calculation of excess properties. The results were good and, in some cases, the values were very close to the experimental ones
Mestrado
Sistemas de Processos Quimicos e Informatica
Mestre em Engenharia Química
Gli stili APA, Harvard, Vancouver, ISO e altri
10

Fouche, Valérie. "Hydroïsomérisation du N-Hexane : activité et stabilité des catalyseurs platine mordénite". Poitiers, 1989. http://www.theses.fr/1989POIT2293.

Testo completo
Abstract (sommario):
Sous pression elevee d'hydrogene (>10 bar) les catalyseurs platine mordenite sont tres selectifs pour l'isomerisation de l'hexane et presentent une tres grande stabilite. Un maximum d'activite est observe pour une valeur du rapport si/al de la charpente zeolithique voisine de 10. Un modele cinetique a ete propose pour rendre compte de l'effet des parametres operatoires sur la vitesse d'isomerisation
Gli stili APA, Harvard, Vancouver, ISO e altri
11

Peksa, Mikuláš, Jan Lang e Milan Kočiřík. "Hexane self-diffusion in bed of glass spheres: testing applicability range of the pore-hopping model". Diffusion fundamentals 16 (2011) 68, S. 1-2, 2011. https://ul.qucosa.de/id/qucosa%3A13810.

Testo completo
Gli stili APA, Harvard, Vancouver, ISO e altri
12

Dwolinski, Thomas. "Multiaxialer Räderprüfstand - Auslegung eines hoch dynamischen Hexapoden mittels moderner Simulationswerkzeuge". Technische Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A21396.

Testo completo
Abstract (sommario):
Der neu entwickelte Multiaxiale Räderprüfstand wurde für hoch dynamische Radkräfte konzipiert. Das Prüfstands-Konzept basiert auf einer Parallelkinematik im Hexapoden-Design. Die Auslegung der Kinematik und der Kräfte wurde mit Creo MDO/MDX durchgeführt. Die grundsätzliche Vorgehensweise wird anhand von Beispielen aufgezeigt. Aufgrund der hohen Dynamik ist es erforderlich das maschinendynamische Verhalten bei der Auslegung zu berücksichtigen. Dazu wurde ein Simulationsmodell des gesamten Prüfstandes in Creo Simulate erstellt und entsprechende Modal- und dynamische Frequenzanalysen durchgeführt. Der grundsätzliche Modellaufbau und Simulationsergebnisse werden vorgestellt. Auch auf die Verifizierung durch Messungen wird eingegangen. Letzter Punkt ist das Ableiten eines geeigneten Sub-Simulations-Modells, welches den Kraftfluss der Hexapoden-Architektur für weitere Untersuchungen richtig abbildet.
Gli stili APA, Harvard, Vancouver, ISO e altri
13

Rincon, Guillermo. "Kinetics of the electrocoagulation of oil and grease". ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/131.

Testo completo
Abstract (sommario):
Research on the electrocoagulation (EC) of hexane extractable materials (HEM) has been conducted at the University of New Orleans using a proprietary bench-scale EC reactor. The original reactor configuration forced the fluid to follow a vertical upward-downward path. An alternate electrode arrangement was introduced so that the path of flow became horizontal. Both configurations were evaluated by comparing the residence time distribution (RTD) data generated in each case. These data produced indication of internal recirculation and stagnant water when the fluid followed a vertical path. These anomalies were attenuated when the fluid flowed horizontally and at a velocity higher than 0.032 m s-1 . A series of EC experiments were performed using a synthetic emulsion with a HEM concentration of approximately 700 mg l-1. It was confirmed that EC of HEM follows first-order kinetics, and kinetic constants of 0.0441 s-1 and 0.0443 s-1 were obtained from applying both the dispersion and tanks-in-series (TIS) models, respectively. In both cases R2 was 0.97. Also, the TIS model indicated that each cell of the EC behaves as an independent continuous-stirred-tank reactor.
Gli stili APA, Harvard, Vancouver, ISO e altri
14

Pieczonka, Tino. "Untersuchung und Visualisierung von Gletschervolumenänderungen im Tarim-Einzugsgebiet, Zentralasien, unter Verwendung multi-temporaler digitaler Geländemodelle". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-234998.

Testo completo
Abstract (sommario):
Das aride Tarim-Becken im Nordwesten Chinas unterliegt Umweltveränderungen, die durch rapide Ausbreitung bewässerter Landwirtschaft sowie Klimawandel angetrieben sind. Während im Oberlauf in den letzten 50 Jahren ein Abflussanstieg beobachtet wurde, haben landwirtschaftliche Aktivitäten im Mittel- und Unterlauf zur Wasserknappheit und der drastischen Verkürzung des endorheischen Flusses geführt. Der Abfluss des Tarim, dessen Hauptzufluss der in Kirgistan entspringende Aksu-Fluss darstellt, wird zu einem großen Teil aus Schnee- und Gletscherschmelze in den oberen Gebirgseinzugsgebieten des Tien Shan gespeist. Da die Unterlieger von dem Wasser des Tarim zur Bewässerung in der Landwirtschaft abhängig sind, sind das Wissen über den Beitrag der Gletscherschmelze zum Abfluss sowie das Wissen über mögliche zukünftige Änderungen der Gletschermasse von großer Relevanz. Zahlreiche Studien beschränken sich oftmals nur auf die Betrachtung der Gletscherfläche, deren Änderung jedoch keine direkten Rückschlüsse auf etwaige Massenänderungen zulässt und zudem nur ein indirektes Signal für Klimaänderungen darstellt. Weiterführende Studien, welche zusätzlich Gletschermassenänderungen im Aksu-Einzugsgebiet untersuchen, haben häufig nur lokalen Charakter. Regionale Studien zu Massenänderungen, welche ganze Einzugsgebiete und Gebirgsketten umfassen, finden sich mehrheitlich für die letzte Dekade durch die Verfügbarkeit laseraltimetrischer Höhendaten und gravimetrischer Messungen, wobei letztere durch hohe Unsicherheiten gekennzeichnet sind. Um jedoch Aussagen hinsichtlich der zeitlichen Entwicklung der Gletscher treffen zu können, widmet sich die Arbeit insbesondere der Untersuchung von Gletschermassenveränderungen seit den 1970er Jahren unter Verwendung deklassifizierter amerikanischer Satellitenbilddaten, SRTM-Daten sowie SPOT-5-Stereodaten. Zur Ableitung geodätischer Gletschermassenbilanzen wurden Daten der Mapping Camera (MC) des Hexagon-Satelliten aus den Jahren 1973–1976 stereoskopisch ausgewertet und mit Daten der SRTM-Mission aus dem Jahr 2000 und SPOT-5-Stereodaten aus dem Jahr 2009 verglichen. Die Ableitung geodätischer Massenbilanzen aus multi-temporalen Geländemodellen erforderte deren Co-Registrierung auf das als SRTM gewählte Master-Modell. In einem zweistufigen Verfahren wurden Verkippungen über eine globale Trendfläche und horizontale Lagefehler über eine analytische Beziehung zwischen Oberflächenneigung, Orientierung und der entsprechenden Höhendifferenz unter Einbeziehung nicht-glazialer Pixel minimiert. Die Eindringtiefe des SRTM-C-Bands wurde mittels ICESat-Daten mit 2,2 m abgeschätzt und bei der Differenzbildung berücksichtigt. Zur Bereinigung der Differenzbilder zwischen den Geländemodellen wurde ein höhenbasierter Ansatz entwickelt, welcher eine abnehmende Varianz der Höhendifferenzwerte vom Ablations- zum Akkumulationsgebiet annimmt. Dieser Ansatz stellt eine deutlich realistischere Annahme im Vergleich zur oftmals verwendeten Nullannahme dar, welche von keinen Veränderungen in den Akkumulationsgebieten ausgeht. Die Gletscher im Aksu-Einzugsgebiet zeigten im Ergebnis einen Massenverlust von 0,35±0,34 m w.e./a im Zeitraum 1975–1999, was dem globalen Durchschnitt für diese Periode entspricht. In den Jahren 1999 bis 2009 wurde indes eine Abnahme des Massenverlusts (0,23±0,19 m w.e./a) festgestellt, was möglicherweise auf eine Zunahme des Niederschlags in der letzten Dekade zurückzuführen ist. Zudem zeigte sich, dass schuttbedeckte Gletscher, deren Schuttauflage ab einer Dicke von etwa 2 cm einen hemmenden Einfluss auf die Abschmelzrate hat, signifikant an Masse verloren haben bei gleichzeitig nur relativ geringer Flächenabnahme. Insgesamt wies die räumliche Verteilung der Massenänderungen eine starke Heterogenität auf, mit zunehmender Tendenz von Osten nach Westen und von den Innen- zu den Außenbereichen des Zentralen Tien Shan. Zusätzlich konnten zahlreiche, zuvor in der Literatur nicht benannte, surgende Gletscher identifiziert werden. Der durch Eismassenverlust induzierte Anteil am Gesamtabfluss des Aksu wurde im Ergebnis mit circa 20% ermittelt. Neben der Oberflächenneigung sind, in einfachen Modellen zur Eisdickenabschätzung, die basale Scherspannung und der Anteil basalen Gleitens an der Oberflächengeschwindigkeit Haupteinflussfaktoren. Anhand gemessener Eisdicken, fernerkundlich abgeleiteter Gletscherfließgeschwindigkeiten und der Oberflächenneigung, als Näherung der Neigung des Gletscherbetts, konnte ein empirischer Zusammenhang zur Abschätzung des Anteils basalen Gleitens abgeleitet werden. Die Eisdickenabschätzung für die vier größten Gletscher des Zentralen Tien Shan erfolgte im weiteren Verlauf durch Anwendung von Glen’s Fließgesetz, unter Annahme laminaren Fließens. Die Ergebnisse weisen für die betrachteten Gletscher mittlere Dicken von 70 m bis 140 m für deren schuttbedeckte Gletscherzungen auf. Diese Werte liegen teilweise deutlich unter denen bisheriger Studien, welche von einer globalen Scherspannung für den gesamten Gletscher oder einem konstanten Anteil basalen Gleitens ausgehen. Im Vergleich zu vorhandenen Eisdickenmessungen konnte durch die lokale Abschätzung der basalen Geschwindigkeit die mittlere Abweichung von zuvor mehr als 200 m auf etwa 50 m reduziert werden. Durch Einbeziehung der in der Arbeit ermittelten geodätischen Gletschermassenbilanzen wurde der relative Volumenverlust seit den 1970er Jahren mit 6% bis 28% quantifiziert, welcher deutlich unter dem schuttfreier Gletscher innerhalb Hochasiens liegt.
Gli stili APA, Harvard, Vancouver, ISO e altri
15

Jiménez, Ibáñez José Emilio. "Análisis y desarrollo de un modelo de tutorización integral basado en el design thinking orientado a la innovación estratégica en empresas colombianas". Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90557.

Testo completo
Abstract (sommario):
The scenario in which this doctoral thesis is developed is Colombia, a country with almost 50 million inhabitants, considered the third country with better environment for business in Latin America. Colombia has an environment con-ducive to business development, but with a low investment in R&D (Research, Development and Innovation). The investment currently has 0.2% of the GDP, and the typology of companies that make up the Colombian business network are in 99,5% of cases Micro, Small and Medium Enterprises (MSME's). This is a challenge for the nation that should consist in increasing the competitiveness of companies to improve economic growth in a new peace scenario. To achieve sustainable development in Colombia, it is necessary for companies to establish innovation strategies that allow them to grow not only in the gener-ation of new products and services, but also in the optimization of processes. The development of competencies in the area of human resources oriented to inno-vation and the proposal of new business models should be the axis that motivate the local economies and in this way that they support the social transformation of the regions of the country. Taking into account this scenario, the challenge of Colombian MSME's is the im-plementation of Design management processes that allow them to become inno-vative companies. In this sense, the ability of Design Thinking as a facilitating tool in the development and implementation of innovation in different compa-nies around the world has been demonstrated. This has been possible thanks to the variety of design-based models that have been created in order to support the development of innovation at all levels. In this thesis, it was evidenced that the innovation processes that employ meth-odologies close to the design not only use the Design Thinking, but that the de-sign process and the traditional design also play an important role in the imple-mentation of the innovation in the companies. There are a large number of methodologies and models based on design process-es that can be understood from Design Thinking, an expression first used by the Hasso Plattner Institute of Design at Stanford University that defines a systemic and integral process based on practices and Methods of design, where creativity is fundamental and innovation is the goal. Its method is based on a deep knowledge of the user, the integration of multidisciplinary profiles, and the solu-tion of the challenges and in the pilot trials of these solutions through proto-types that the same end users test before being produced. After analyzing the following six different models: 1) the Third Hybrid Space, 2) Innovation as a Learning Process, 3) Open Book for Social Innovation, 4) 101 Design Methods, 5) Human-Centered Design, and 6) The Double Diamond, the most suitable was two of them, The Double Diamond and the Open Book for So-cial Innovation, because they work the innovation from the three dimensions of the company: Strategic, Tactical and Operative and each of both from the factors: Innovation, Users, Market and Technology, a qualitative and quantitative analy-sis. At the same time, the set of design methods and methodologies that under the name of Design Practices for Business (PND - Prácticas de Diseño para los Negocios in Spanish) was used as the basis for defining the tools that would be used later in the new model to be created. The Double Hexagon is formulated as a model that, applying the PDN, allows a MSME's to implement innovation as a strategic factor that not only creates an innovation, but also implies that the company becomes an innovative company.
El escenario en el que se desarrolla esta tesis doctoral es Colombia, un país con casi 50 millones de habitantes, considerado el tercer país con mejor ambiente para los negocios en Latinoamérica lo que supone un entorno propicio para el desarrollo empresarial, pero con una baja inversión en I+D+i (Investigación, Desarrollo e Innovación). La inversión presenta en la actualidad un 0,2% del PIB sumado a la tipología de empresas que conforman el tejido empresarial colom-biano con un 99,5% de Micro, Pequeñas y Medianas Empresas (MIPYME). Ello presenta un reto como nación que debería consistir en un aumento de la compe-titividad de las empresas para mejorar el crecimiento económico en un nuevo escenario de paz. Para lograr un desarrollo sostenible en Colombia, es necesario que las empresas establezcan estrategias de innovación que les permita crecer no sólo en la gene-ración de nuevos productos y servicios, sino también en la optimización de los procesos. El desarrollo de competencias en el área de recursos humanos orienta-do a la innovación y la propuesta de nuevos modelos de negocio deben ser los ejes que motiven las economías locales y de esta manera que apoyen la trans-formación social de las regiones del país. Teniendo en cuenta este panorama, el reto de las MIPYPE colombianas es la im-plementación de procesos de gestión de Diseño que les permita transformarse en empresas innovadoras. En este sentido, se ha demostrado la capacidad que tiene el Design Thinking como herramienta de facilitación en el desarrollo e implemen-tación de la innovación en diferentes empresas alrededor del mundo. Esto ha sido posible gracias a la variedad de modelos basados en diseño que se han creado con el fin de apoyar el desarrollo de la innovación a todos los niveles. En esta tesis doctoral se evidenció que los procesos de innovación que emplean metodologías cercanas al diseño no sólo usan el Design Thinking, sino que el pro-ceso de diseño y el diseño tradicional también juegan un papel importante en la implementación de la innovación en las empresas. Existen un gran número de metodologías y modelos basados en procesos de diseño que pueden ser entendidos desde el Design Thinking, una expresión acuña-da por el Hasso Plattner Institute of Design en la Universidad de Stanford que define un proceso sistémico e integral basado en prácticas y métodos de diseño, donde la creatividad es fundamental y la innovación es el objetivo. Su método se basa en un profundo conocimiento del usuario, la integración de perfiles multidisci-plinarios, en la solución de los retos y en el pilotaje de estas soluciones a través de prototipos que prueban los mismos usuarios finales antes de ser producidos. Después de analizar seis modelos diferentes: 1) el Tercer Espacio Híbrido, 2) la Innovación como Proceso de Aprendizaje, 3) el Libro Abierto para la Innovación Social, 4) los 101 Métodos de Diseño, 5) el Human-Centered Design y 6) el Double Diamond desde las tres dimensiones de la empresa: Estratégica, Táctica y Operati-va y cada uno de estas desde los factores: Innovación, Usuarios, Mercado y Tec-nología, se realizó un análisis cualitativo y cuantitativo que facilitó la selección final de dos de ellos como los más idóneos. Paralelamente se definió de manera global el conjunto de métodos y metodolo-gías de diseño que bajo el nombre Prácticas de Diseño para los Negocios (PND) sirviera de base para definir las herramientas que serían utilizadas posteriormen-te en el nuevo modelo a crear. El Doble hexágono se formula como un modelo que aplicando las PDN, permite que una MIPYME implemente la innovación como un factor estratégico, es decir, que no solo haga innovación, sino que sea una empresa innovadora.
L'escenari en el qual es desenvolupa aquesta tesi doctoral és Colòmbia, un país amb quasi 50 milions d'habitants, considerat el tercer país amb millor ambient per als negocis a Llatinoamèrica el que suposa un entorn propici per al desenvolupament empresarial, però amb una baixa inversió en R+D+i (Recerca, Desenvolupament i Innovació). La inversió presenta en l'actualitat un 0,2% del PIB sumat a la tipologia d'empreses que conformen el teixit empresarial colombià amb un 99,5% de Micro, Xicotetes i Mitges Empreses (MIPIME). Açò presenta un repte com a nació que hauria de consistir en un augment de la competitivitat de les empreses per a millorar el creixement econòmic en un nou escenari de pau. Per a aconseguir un desenvolupament sostenible a Colòmbia, és necessari que les empreses establisquen estratègies d'innovació que els permeta créixer no solament en la generació de nous productes i serveis, sinó també en l'optimització dels processos. El desenvolupament de competències en l'àrea de recursos humans orientat a la innovació i la proposta de nous models de negoci han de ser els eixos que motiven les economies locals i d'aquesta manera que recolzen la transformació social de les regions del país. Tenint en compte aquest panorama, el repte de les MIPIME colombianes és la implementació de processos de gestió de Disseny que els permeta transformar-se en empreses innovadores. En aquest sentit, s'ha demostrat la capacitat que té el Design Thinking com a eina de facilitació en el desenvolupament i implementació de la innovació en diferents empreses al voltant del món. Açò ha sigut possible gràcies a la varietat de models basats en disseny que s'han creat amb la finalitat de recolzar el desenvolupament de la innovació a tots els nivells. En aquesta tesi doctoral es va evidenciar que els processos d'innovació que empren metodologies properes al disseny no solament usen el Design Thinking, sinó que el procés de disseny i el disseny tradicional també juguen un paper important en la implementació de la innovació en les empreses. Existeixen un gran nombre de metodologies i models basats en processos de disseny que poden ser entesos des del Design Thinking, una expressió encunyada pel Hasso Plattner Institute of Design en la Universitat de Stanford que defineix un procés sistemic i integral basat en pràctiques i mètodes de disseny, on la creativitat és fonamental i la innovació és l'objectiu. El seu mètode es basa en un profund coneixement de l'usuari, la integració de perfils multidisciplinaris, en la solució dels reptes i en el pilotatge d'aquestes solucions a través de prototips que proven els mateixos usuaris finals abans de ser produïts. Després d'analitzar sis models diferents: 1) el Tercer Espai Híbrid, 2) la Innovació com a Procés d'Aprenentatge, 3) el Llibre Obert per a la Innovació Social, 4) els 101 Mètodes de Disseny, 5) el Human-Centered Design i 6) el Double Diamond des de les tres dimensions de l'empresa: Estratègica, Tàctica i Operativa i cadascun d'aquestes des dels factors: Innovació, Usuaris, Mercat i Tecnologia, es va realitzar una anàlisi qualitativa i quantitatiu que va facilitar la selecció final de dues d'ells com els més idonis. Paral·lelament es va definir de manera global el conjunt de mètodes i metodologies de disseny que sota el nom Pràctiques de Disseny per als Negocis (PND) servira de base per a definir les eines que serien utilitzades posteriorment en el nou model a crear. El Doble hexàgon es formula com un model que aplicant les PDN, permet que una MIPIME implemente la innovació com un factor estratègic, és a dir, que no solament faça innovació, sinó que siga una empresa innovadora. En el segon hexàgon que correspon a l'Apoderament Col·laboratiu es genera de nou una transferència de coneixement i/o de tecnologia que li permet a la MIPIME continuar amb la seua innovació de manera autònoma.
Jiménez Ibáñez, JE. (2017). Análisis y desarrollo de un modelo de tutorización integral basado en el design thinking orientado a la innovación estratégica en empresas colombianas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90557
TESIS
Gli stili APA, Harvard, Vancouver, ISO e altri
16

Vymazal, Aleš. "Biologicky inspirovaní roboti - brouk". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-416669.

Testo completo
Gli stili APA, Harvard, Vancouver, ISO e altri
17

Khusheef, Ahmed S. "Investigation on the mobile robot navigation in an unknown environment". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/537.

Testo completo
Abstract (sommario):
Mobile robots could be used to search, find, and relocate objects in many types of manufacturing operations and environments. In this scenario, the target objects might reside with equal probability at any location in the environment and, therefore, the robot must navigate and search the whole area autonomously, and be equipped with specific sensors to detect objects. Novel challenges exist in developing a control system, which helps a mobile robot achieve such tasks, including constructing enhanced systems for navigation, and vision-based object recognition. The latter is important for undertaking the exploration task that requires an optimal object recognition technique. In this thesis, these challenges, for an indoor environment, were divided into three sub-problems. In the first, the navigation task involved discovering an appropriate exploration path for the entire environment, with minimal sensing requirements. The Bug algorithm strategies were adapted for modelling the environment and implementing the exploration path. The second was a visual-search process, which consisted of employing appropriate image-processing techniques, and choosing a suitable viewpoint field for the camera. This study placed more emphasis on colour segmentation, template matching and Speeded-Up Robust Features (SURF) for object detection. The third problem was the relocating process, which involved using a robot’s gripper to grasp the detected, desired object and then move it to the assigned, final location. This also included approaching both the target and the delivery site, using a visual tracking technique. All codes were developed using C++ and C programming, and some libraries that included OpenCV and OpenSURF were utilized for image processing. Each control system function was tested both separately, and then in combination as a whole control program. The system performance was evaluated using two types of mobile robots: legged and wheeled. In this study, it was necessary to develop a wheeled search robot with a high performance processor. The experimental results demonstrated that the methodology used for the search robots was highly efficient provided the processor was adequate. It was concluded that it is possible to implement a navigation system within a minimum number of sensors if they are located and used effectively on the robot’s body. The main challenge within a visual-search process is that the environmental conditions are difficult to control, because the search robot executes its tasks in dynamic environments. The additional challenges of scaling these small robots up to useful industrial capabilities were also explored.
Gli stili APA, Harvard, Vancouver, ISO e altri
18

Calbiac, Hortense de. "Mechanisms of C9ORF72 pathogenicity and related autophagy impairment in amyotrophic lateral sclerosis Sqstm1 knockdown causes a locomotor phenotype ameliorated by rapamycin in a zebrafish model of ALS/FTLD Depdc5 knockdown causes mTOR-dependent motor hyperactivity in zebrafish". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS561.

Testo completo
Abstract (sommario):
Pour analyser les mécanismes pathogéniques de la mutation de SQSTM1 dans la SLA, nous avons développé un modèle d’haploinsuffisance de sqstm1 chez le poisson zèbre. La perte de fonction de ce gène induit un phénotype moteur caractéristique de la SLA. Pour élucider les mécanismes entraînant la dégénérescence des motoneurones dans cette maladie, nous avons étudié les interactions épistatiques de c9orf72 et de sqstm1 chez le poisson zèbre et nous avons observé que les deux protéines appartiennent à une voie cellulaire commune, avec c9orf72 agissant en aval de sqstm1. Dans des cultures primaires de motoneurones de souris, nous avons démontré que la perte de ces gènes entraîne la mort des motoneurones associée à des défauts de l’autophagie. Afin de développer un modèle qui récapitulerait les différents mécanismes de la mutation de C9ORF72 dans la SLA, nous avons combiné l’inhibition partielle de ce gène avec l’expression des DPRs chez le poisson zèbre. Cela induit un phénotype moteur caractérisé par des défauts locomoteurs et une paralysie. En particulier, nous avons observé que les répétitions de GP s’accumulent lorsque c9orf72 est inhibé. Ceci est associé à une accumulation de SQSTM1/p62 ainsi qu’à la perte des motoneurones. Ces phénotypes sont limités lors de l’inhibition de la caspase 9, un régulateur essentiel de l’apoptose. De plus, en activant l’autophagie avec la rapamycine, nous avons amélioré la clairance des GP et de p62, restaurant ainsi les paramètres moteurs. Ces résultats montrent que la toxicité des DPRs est relative au niveau de de l’expression de C9ORF72, suggérant que le gain et la perte de fonction synergisent dans la pathogénicité de C9ORF72
To investigate the pathogenic mechanisms induced by SQSTM1 mutations in ALS, we developed a zebrafish model of sqstm1 haploinsufficiency. We observed that loss of function of sqstm1 leads to a specific motor phenotype. To elucidate the common cellular mechanisms underlying motor neuron degeneration in ALS, we analyzedc9orf72 and sqstm1 epistatic interactions inzebrafish. C9orf72 and sqstm1 partial inhibitions have an additive effect and C9ORF72 rescues the phenotype induced by sqstm1 knockdown. Thus, both proteins belong to the same pathway and c9orf72 acts downstream of sqstm1. Also, we observed that depletion of these genes in mouse motor neurons primary cultures leads to the early death of motor neurons associated with autophagy impairment. To develop a vertebrate model that recapitulates the different mechanisms associated withthe C9ORF72 HRE pathogenicity in ALS, we combined the partial inhibition of c9orf72 with the expression of the DPRs in zebrafish. This induces a robust motor phenotype characterized by locomotor defects and paralysis. Focusing on GP repeats, we observed that the loss of function of c9orf72 is essential to inhibitpoly(GP) clearance.This is associated with SQSTM1/p62 accumulation, severe motor neurons abnormalities and loss. These phenotypes are rescued by the inhibition of caspase 9, a regulator of apoptosis. Also, rapamycinis able to improve the clearance of poly(GP) and p62, with restored swim and motor neurons features, thus confirming the role of C9ORF72 in autophagy.These results show that DPR toxicity is related to lowered expression of C9ORF72, suggesting that both gain and loss of function synergize in the C9ORF72 HRE pathogenicity
Gli stili APA, Harvard, Vancouver, ISO e altri
19

Jerónimo, Rui José Pinto de Moura. "As preferências publicitárias em função da personalidade: Um caso de estudo sobre smartphones". Master's thesis, 2020. http://hdl.handle.net/10362/94325.

Testo completo
Abstract (sommario):
Dissertation presented as the partial requirement for obtaining a Master's degree in Statistics and Information Management, specialization in Marketing Research e CRM
A importância dos dados psicográficos – como a personalidade, os valores e as crenças – para melhor conhecer os clientes é conhecida e correntemente utilizada, ainda que indiretamente, em diversas áreas de negócio. Não obstante, verifica-se ainda alguma apreensão em recorrer a este tipo de informação, quer pela dificuldade de obtenção da mesma, por ter uma abordagem complexa, ou por se considerarem dados subjetivos e muito dependentes do contexto em que são recolhidos. A literatura oferece, no entanto, algumas soluções cada vez mais expeditas para se obter este tipo de dados e comprova existir uma relação entre os conteúdos pelos quais alguém se interessa e a sua personalidade. Esta dissertação pretende não só explicar essas relações, de modo a facilitar a caraterização psicográfica de uma população-alvo, mas principalmente avaliar a possibilidade de se verificarem, para cada segmento dessa população, diferentes reações aos vários estímulos publicitários utilizados no relacionamento com o cliente. Com base na literatura e através do desenvolvimento e aplicação de um questionário, foi possível conhecer as estratégias de influência mais adequadas a cada segmento de clientes. Para tal, foi ainda criado um modelo preditivo que permite prever qual a campanha publicitária com que cada cliente mais se deverá identificar. Com esta abordagem, comprovou-se o valor da personalidade para um melhor conhecimento da população-alvo. Verificou-se que, com recurso a modelos preditivos, é possível identificar os clientes mais suscetíveis de estar interessados em receber publicidade, bem como personalizar as mensagens publicitárias utilizadas com cada cliente, tornando-as assim mais relevantes.
The importance of psychographic data – such as personality, values and beliefs – to better understand customers is well recognized and already used in some areas of business. However, there’s still a generalized apprehension about resorting to this type of information, either because of the difficulty in obtaining it, for its complex approach, or for considering it subjective and very dependent on the context in which is collected. However, the literature offers some increasingly simpler solutions for obtaining this type of data and proves that there is a relationship between our content preferences (books, music, movies, hobbies) and our personality. This master thesis aims not only to explain the relations between content and personality, in order to facilitate the psychographic characterization of a target population, but most importantly to evaluate the possibility of an existing relation between people’s personality and their reaction to different advertising stimuli. Based on the literature and through the development and the application of a questionnaire, it was thus possible to know the most appropriate influence strategies for each customer segment. To this end, it was also created a predictive model that allows us to know which advertising campaign each customer most identifies with. With this approach, the value of personality to better understand the target population has been proven. It was found that, using predictive models, it was possible to identify the customers most likely to be interested in receiving advertising, as well as to customize the advertising messages used with each customer, thus making them more relevant.
Gli stili APA, Harvard, Vancouver, ISO e altri
20

Hsieh, Sen-Teng, e 謝森騰. "The Relationships among Career Self−Efficacy and Happiness of Junior High School Students in Taichung City : The Moderating Effect of HEXACO personality model". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/rnpwp3.

Testo completo
Abstract (sommario):
碩士
國立彰化師範大學
教育研究所
106
The purpose of this study was to explore the relationships among career self−efficacy and happiness of junior high school students in Taichung City and the moderating effect of HEXACO personality model. The participant were 955 seven to ninth grade students from seven junior high schools in Taichung City (including middle school). The instruments included Career Self−efficacy Scale, Happiness Scale, HEXACO−60 personality Scale. The data obtained were analyzed by descriptive statistics, two−way ANOVA, multiple regression analysis, hierarchical regression analysis and other statistical methods to verify assumptions. The results of this study as follows: The score level of career self−efficacy and happiness in junior high school students was a little higher than the medium level, and the honesty−humility was the highest dimension of the HEXACO personality. There were significant different of career self−efficacy, happiness, HEXACO personality to different background variables, including gender and grade. Female students were significantly higher career self−efficacy than male students. Second−graders of junior high school students were higher than third−graders of junior high school students on happiness. Female students got significantly higher personality score than male students on honesty-humility, emotionality, agreeableness, conscientiousness and openness to experience. Career self−efficacy can positively predict happiness. HEXACO personality model was a moderated effect between career self−efficacy and happiness. Finally, based on the results of the study, the researcher made some practical suggestions for school administrative units, school teachers' teaching and future researchers.
Gli stili APA, Harvard, Vancouver, ISO e altri
21

Torres, Ann L. "Virtual Model Control of a Hexapod Walking Robot". 1996. http://hdl.handle.net/1721.1/7083.

Testo completo
Abstract (sommario):
Since robots are typically designed with an individual actuator at each joint, the control of these systems is often difficult and non-intuitive. This thesis explains a more intuitive control scheme called Virtual Model Control. This thesis also demonstrates the simplicity and ease of this control method by using it to control a simulated walking hexapod. Virtual Model Control uses imagined mechanical components to create virtual forces, which are applied through the joint torques of real actuators. This method produces a straightforward means of controlling joint torques to produce a desired robot behavior. Due to the intuitive nature of this control scheme, the design of a virtual model controller is similar to the design of a controller with basic mechanical components. The ease of this control scheme facilitates the use of a high level control system which can be used above the low level virtual model controllers to modulate the parameters of the imaginary mechanical components. In order to apply Virtual Model Control to parallel mechanisms, a solution to the force distribution problem is required. This thesis uses an extension of Gardner`s Partitioned Force Control method which allows for the specification of constrained degrees of freedom. This virtual model control technique was applied to a simulated hexapod robot. Although the hexapod is a highly non-linear, parallel mechanism, the virtual models allowed text-book control solutions to be used while the robot was walking. Using a simple linear control law, the robot walked while simultaneously balancing a pendulum and tracking an object.
Gli stili APA, Harvard, Vancouver, ISO e altri
22

Sinclair, Andrew. "A tile assembly model with hexagon shaped tiles". 2015. http://hdl.handle.net/1993/30147.

Testo completo
Abstract (sommario):
The field of nanotechnology has enabled scientists to perform fascinating engineering manipulations of biological substrates. Systems of DNA are now able to perform algorithmic computations by way of constructing biological modules composed of DNA macromolecules and using laboratory techniques available to biological sciences. The tile assembly model is an established model of biomolecular computing: using properties of DNA macromolecules to define constructions of self-assembling biological systems. The existing tile assembly model uses the concept of DNA tiles conceptually shaped as squares and exposes the tiles to carefully controlled biological conditions. The result is that under this process we can design and create these systems to compute solutions to algorithmic problems. Hexagons are the only two-dimensional regular polygon other than squares that can tile a plane infinitely leaving no space uncovered, where only translations of the initial polygon is allowed. Therefore hexagon-shaped DNA tiles can be defined to cover a planar surface, with the notable difference of six adjacent tiles per position versus the four adjacent neighbours in traditional four sided tiles. In this thesis, we will define a generalization of the tile assembly model that supports six-sided DNA tiles, in addition to the traditional four sides. We will introduce a problem known as the 0-1 Knapsack problem that is currently unsolved with square tiles. Moreover, a solution to the problem was attempted by tile assembly model researchers, however we show there is an error in their solution. After we analyze their solution and discover the shortcomings of square tiles under those constraints, we then show this fault is not applicable to hexagon tiles. Therefore, we show that the 0-1 Knapsack problem is solvable using hexagon shaped tiles.
Gli stili APA, Harvard, Vancouver, ISO e altri
23

SHEN, YU-HOW, e 沈昱豪. "New Ductile Fracture Model of Hexagon Flange Nut in Cold Forging". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/55k4zz.

Testo completo
Abstract (sommario):
碩士
國立高雄應用科技大學
模具工程系
106
This study mainly predicts the crack position of the outer hexagonal flange nut during cold forging, and finds that most of the fracture forms exhibit shear stress damage close to 45°, instead of the tensile force proposed by Cockcroft and Latham stress caused damage, so a new ductile failure mode was proposed to verify The new ductile failure mode is mainly based on the ductile failure caused by the strain energy generated when the maximum shear stress occurs, and the theoretical integral is converted into a sub-program and added to the ductile failure module of the finite element analysis software DEFORM. The composite extrusion case is simulated to predict whether the fracture form meets the requirements. Then, based on the discussion of this paper, the hex flange nut forming is used to simulate the fracture form and stress analysis, and finally the forging failure mode commonly used for forging is Normalized Cockcroft and Latham as a comparison of its applicability. After comparing the results of the previous two examples, it is found that the Normalized Cockcroft and Latham modes are consistent with the new ductile failure mode in predicting the rupture position, and the new ductile failure mode is more accurate in predicting the rupture trend.
Gli stili APA, Harvard, Vancouver, ISO e altri
24

Gaughan, Eric Thomas. "Examining the predictive and incremental validity of two general models of personality a study of psychopathy using the HEXACO-PI-R and NEO PI-R /". 2009. http://purl.galileo.usg.edu/uga%5Fetd/gaughan%5Feric%5Ft%5F200905%5Fms.

Testo completo
Gli stili APA, Harvard, Vancouver, ISO e altri
25

Gagné, Michelle. "Caractérisation de la pharmacocinétique suite à l’exposition multivoie au toluène, au n-hexane et au cyclohexane chez le rat". Thèse, 2008. http://hdl.handle.net/1866/2817.

Testo completo
Abstract (sommario):
La contribution de l’inhalation et de la voie percutanée à l’exposition totale à des composés organiques volatils (COV) présents dans l’eau potable est une problématique qui suscite un intérêt grandissant en santé publique et au niveau réglementaire. Jusqu’à tout récemment, seule l’ingestion était considérée dans l’évaluation du risque des contaminants de l’eau. L’objectif de ce projet était de caractériser l’impact de l’exposition multivoie sur la pharmacocinétique et la dose interne de trois COV : le toluène (TOL), le n-hexane (HEX) et le cyclohexane (CYCLO). À cette fin, un modèle expérimental animal a été utilisé et un modèle toxicocinétique à base physiologique (TCBP) a été adapté pour le TOL. Des rats Sprague-Dawley ont été exposés par voies uniques (inhalation, orale et percutanée) ou simultanées (multivoie) aux solvants. Pour le TOL, les trois voies ont été expérimentées, alors que la voie percutanée n’a pas été retenue pour le HEX et le CYCLO. Des prélèvements sanguins ont permis de caractériser les cinétiques sanguines. Les niveaux sanguins, obtenus lors des expositions multivoies, étaient généralement plus élevés que la somme des niveaux associés aux expositions par voies uniques, fait illustré par le rapport des surfaces sous la courbe expérimentale versus les prédictions (TOL : 1,30 et 2,19 ; HEX : 1,55 ; CYCLO : 0,98 et 0,99). Le modèle TCBP prédit bien la cinétique du TOL lors d’expositions par voies uniques et par multivoies. Les données expérimentales obtenues suggèrent que la dose interne résultant d’une exposition multivoie ne peut pas toujours être prédite par la somme des doses internes obtenues lors d’expositions par voies uniques. Ce phénomène serait explicable par la saturation du métabolisme. La modélisation TCBP est un outil efficace pour l’estimation du risque relatif à l’exposition multivoie aux COV présents dans l’eau potable.
The contribution of dermal and inhalation routes of exposure to volatile organic chemicals (VOCs) in drinking water is increasingly drawing attention. Until recently, ingestion was the only route considered in risk assessment of drinking water contaminants. The general objective of this study was to characterize multi-route exposures on the pharmacokinetics and internal dose of three VOCs: toluene (TOL), n-hexane (HEX) and cyclohexane (CYCLO). Towards this goal, an experimental animal model was developed and a physiologically-based toxicokinetic (PBTK) model was adapted in order to take account route-specific absorption parameters of TOL. Sprague-Dawley rats were given a single dose of VOCs by oral ingestion, inhalation or dermal route. Additional groups of rat were exposed by the three routes simultaneously. In the case of HEX and CYCLO, dermal route was not considered. Blood samples were collected in order to compare kinetics following simple and multiroute exposures. Blood levels obtained following multiroute exposures were generally higher than predictions (i.e., the sum of the blood levels obtained for single route exposures) (as revealed by area under curve ratio: TOL :1,30 et 2,19; HEX : 1,55; CYCLO : 0,98 et 0,99). The PBTK model described adequately the kinetics of TOL in rats following single and multiroute exposures. The results suggest that internal dose arising from multiple routes is not necessarely comparable to the sum of the blood levels obtained for single route exposures. This phenomenon would be attributable to degree of saturation during aggregate exposures. Furthermore, the present study demonstrated that PBTK model can be used to predict/interpret blood levels associated with multiroute exposures to VOCs in drinking water, using toluene as a model substance.
Gli stili APA, Harvard, Vancouver, ISO e altri
26

Cilliers, Christiaan Petrus. "A semiotic multimodal analysis and South African case study: the representation and construction of masculinities in men's health (Sa)". Thesis, 2014. http://hdl.handle.net/10500/18197.

Testo completo
Abstract (sommario):
The main question of this study was: How and in what way can a multimodal semiotic visual analysis model be developed and used for contributing to the analysis and understanding of the manner in which the Men’s Health (South Africa) magazine – as a case study – represents and constructs masculinities in South Africa? The following three subsidiary research questions were formulated to address this topic: • What is the literature revealing with reference to the media as producers of meaning in relation to masculinity and visual texts? • How and in which way can a semiotic visual analysis multimodal model be developed with the purpose of contributing to the analysis of visual texts? • What is the outcome of the visual analysis multimodal model with reference to the case study about the representation and construction of masculinities in visual texts in MH? The first aim of this research was to establish an overview of masculinities and to explore the visual representation of masculinity with reference to mediation, reality, and ideology in the media. With reference to the media as producers of meaning in relation to masculinity and visual texts, a semiotic visual analysis and social semiotics were used to unpack culture as a site of the production of meanings. The media is one of the main sources from which men receive their entertainment and information about the world. In this sense, the media makes sense of the world. Mass media plays a key role in discourse and constructing the relationships between reality and ideology. During this construction, the media reflects on existing opinions and attitudes in society. A quantitative content analysis and a qualitative semiotic multimodal visual analysis were conducted on 27 visual texts purposively selected from MH to include editions from July 2010 to June 2011. This population covered 12 front covers, 12 editorials and three flip covers. The developed visual multimodal model was tested qualitatively on nine visual texts since these texts included the front covers, flip covers and editorials of the three editions with flip covers. v A second major aim of the study was to establish the way in which a semiotic visual analysis multimodal model needed to be developed and used for analysing visual texts, as well as for analysing the visual texts according to the multimodal model in order to understand how the multimodality and social semiotic resources were applied in MH to represent and construct masculinities. The rationale for the development and design of this model was based on the premise that a basic understanding of semiotics and visual language was needed. Without such an understanding, the vast amounts of visual messages that confront the reader would remain incomprehensible. Consequently, a productive dialogue in relation to visual communication cannot take place. The multimodal model developed in this thesis highlights visual text layout, in conjunction with language-in-use, that does not occur in isolation and that is deeply reliant on other forms of making meaning. The heptagon multimodal model consists of concept maps of the six functions of the designed hexagon model. This multimodality approach includes analysing simultaneously occurring semiotics and their various roles in conjunction with detailed, all-inclusive discourses. In the quantitative content analysis and the qualitative multimodal semiotic analysis, the six components of the developed heptagon model (visual grammar, positioning, typography, colour, modality, and iconography) are illustrated. The quantitative research supported the main research design, i.e. the qualitative multimodal semiotic analysis. It is envisaged that the development and construction of a multimodal semiotic model will make a contribution to the scholarly field of semiotic analysis. By discussing the fluidity of the variations of masculinities and male identities, by giving a brief overview of the role of the media in constructing masculinities, and by focusing on the discourses that took place in MH, the researcher creates an awareness of the inherited patriarchal masculinities by recommending envisioned masculinities to be inclusive as a component of the solution. This approach is illustrated by the use and findings of the multimodal semiotic visual analysis.
Communication Science
D. Litt. et. Phil
Gli stili APA, Harvard, Vancouver, ISO e altri
27

Pieczonka, Tino. "Untersuchung und Visualisierung von Gletschervolumenänderungen im Tarim-Einzugsgebiet, Zentralasien, unter Verwendung multi-temporaler digitaler Geländemodelle". Doctoral thesis, 2017. https://tud.qucosa.de/id/qucosa%3A30942.

Testo completo
Abstract (sommario):
Das aride Tarim-Becken im Nordwesten Chinas unterliegt Umweltveränderungen, die durch rapide Ausbreitung bewässerter Landwirtschaft sowie Klimawandel angetrieben sind. Während im Oberlauf in den letzten 50 Jahren ein Abflussanstieg beobachtet wurde, haben landwirtschaftliche Aktivitäten im Mittel- und Unterlauf zur Wasserknappheit und der drastischen Verkürzung des endorheischen Flusses geführt. Der Abfluss des Tarim, dessen Hauptzufluss der in Kirgistan entspringende Aksu-Fluss darstellt, wird zu einem großen Teil aus Schnee- und Gletscherschmelze in den oberen Gebirgseinzugsgebieten des Tien Shan gespeist. Da die Unterlieger von dem Wasser des Tarim zur Bewässerung in der Landwirtschaft abhängig sind, sind das Wissen über den Beitrag der Gletscherschmelze zum Abfluss sowie das Wissen über mögliche zukünftige Änderungen der Gletschermasse von großer Relevanz. Zahlreiche Studien beschränken sich oftmals nur auf die Betrachtung der Gletscherfläche, deren Änderung jedoch keine direkten Rückschlüsse auf etwaige Massenänderungen zulässt und zudem nur ein indirektes Signal für Klimaänderungen darstellt. Weiterführende Studien, welche zusätzlich Gletschermassenänderungen im Aksu-Einzugsgebiet untersuchen, haben häufig nur lokalen Charakter. Regionale Studien zu Massenänderungen, welche ganze Einzugsgebiete und Gebirgsketten umfassen, finden sich mehrheitlich für die letzte Dekade durch die Verfügbarkeit laseraltimetrischer Höhendaten und gravimetrischer Messungen, wobei letztere durch hohe Unsicherheiten gekennzeichnet sind. Um jedoch Aussagen hinsichtlich der zeitlichen Entwicklung der Gletscher treffen zu können, widmet sich die Arbeit insbesondere der Untersuchung von Gletschermassenveränderungen seit den 1970er Jahren unter Verwendung deklassifizierter amerikanischer Satellitenbilddaten, SRTM-Daten sowie SPOT-5-Stereodaten. Zur Ableitung geodätischer Gletschermassenbilanzen wurden Daten der Mapping Camera (MC) des Hexagon-Satelliten aus den Jahren 1973–1976 stereoskopisch ausgewertet und mit Daten der SRTM-Mission aus dem Jahr 2000 und SPOT-5-Stereodaten aus dem Jahr 2009 verglichen. Die Ableitung geodätischer Massenbilanzen aus multi-temporalen Geländemodellen erforderte deren Co-Registrierung auf das als SRTM gewählte Master-Modell. In einem zweistufigen Verfahren wurden Verkippungen über eine globale Trendfläche und horizontale Lagefehler über eine analytische Beziehung zwischen Oberflächenneigung, Orientierung und der entsprechenden Höhendifferenz unter Einbeziehung nicht-glazialer Pixel minimiert. Die Eindringtiefe des SRTM-C-Bands wurde mittels ICESat-Daten mit 2,2 m abgeschätzt und bei der Differenzbildung berücksichtigt. Zur Bereinigung der Differenzbilder zwischen den Geländemodellen wurde ein höhenbasierter Ansatz entwickelt, welcher eine abnehmende Varianz der Höhendifferenzwerte vom Ablations- zum Akkumulationsgebiet annimmt. Dieser Ansatz stellt eine deutlich realistischere Annahme im Vergleich zur oftmals verwendeten Nullannahme dar, welche von keinen Veränderungen in den Akkumulationsgebieten ausgeht. Die Gletscher im Aksu-Einzugsgebiet zeigten im Ergebnis einen Massenverlust von 0,35±0,34 m w.e./a im Zeitraum 1975–1999, was dem globalen Durchschnitt für diese Periode entspricht. In den Jahren 1999 bis 2009 wurde indes eine Abnahme des Massenverlusts (0,23±0,19 m w.e./a) festgestellt, was möglicherweise auf eine Zunahme des Niederschlags in der letzten Dekade zurückzuführen ist. Zudem zeigte sich, dass schuttbedeckte Gletscher, deren Schuttauflage ab einer Dicke von etwa 2 cm einen hemmenden Einfluss auf die Abschmelzrate hat, signifikant an Masse verloren haben bei gleichzeitig nur relativ geringer Flächenabnahme. Insgesamt wies die räumliche Verteilung der Massenänderungen eine starke Heterogenität auf, mit zunehmender Tendenz von Osten nach Westen und von den Innen- zu den Außenbereichen des Zentralen Tien Shan. Zusätzlich konnten zahlreiche, zuvor in der Literatur nicht benannte, surgende Gletscher identifiziert werden. Der durch Eismassenverlust induzierte Anteil am Gesamtabfluss des Aksu wurde im Ergebnis mit circa 20% ermittelt. Neben der Oberflächenneigung sind, in einfachen Modellen zur Eisdickenabschätzung, die basale Scherspannung und der Anteil basalen Gleitens an der Oberflächengeschwindigkeit Haupteinflussfaktoren. Anhand gemessener Eisdicken, fernerkundlich abgeleiteter Gletscherfließgeschwindigkeiten und der Oberflächenneigung, als Näherung der Neigung des Gletscherbetts, konnte ein empirischer Zusammenhang zur Abschätzung des Anteils basalen Gleitens abgeleitet werden. Die Eisdickenabschätzung für die vier größten Gletscher des Zentralen Tien Shan erfolgte im weiteren Verlauf durch Anwendung von Glen’s Fließgesetz, unter Annahme laminaren Fließens. Die Ergebnisse weisen für die betrachteten Gletscher mittlere Dicken von 70 m bis 140 m für deren schuttbedeckte Gletscherzungen auf. Diese Werte liegen teilweise deutlich unter denen bisheriger Studien, welche von einer globalen Scherspannung für den gesamten Gletscher oder einem konstanten Anteil basalen Gleitens ausgehen. Im Vergleich zu vorhandenen Eisdickenmessungen konnte durch die lokale Abschätzung der basalen Geschwindigkeit die mittlere Abweichung von zuvor mehr als 200 m auf etwa 50 m reduziert werden. Durch Einbeziehung der in der Arbeit ermittelten geodätischen Gletschermassenbilanzen wurde der relative Volumenverlust seit den 1970er Jahren mit 6% bis 28% quantifiziert, welcher deutlich unter dem schuttfreier Gletscher innerhalb Hochasiens liegt.
Gli stili APA, Harvard, Vancouver, ISO e altri
Offriamo sconti su tutti i piani premium per gli autori le cui opere sono incluse in raccolte letterarie tematiche. Contattaci per ottenere un codice promozionale unico!

Vai alla bibliografia