• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 751
  • 209
  • 174
  • 143
  • 116
  • 88
  • 32
  • 31
  • 19
  • 16
  • 15
  • 14
  • 10
  • 6
  • 5
  • Tagged with
  • 1899
  • 363
  • 219
  • 114
  • 111
  • 110
  • 110
  • 110
  • 109
  • 97
  • 96
  • 94
  • 92
  • 90
  • 89
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

3-Dimensional Model and Simulations of Sperm Movement

Zhang, Yunyun 24 April 2013 (has links)
In this project we are building a mathematical model to track the movement of spermatozoa during the process of chemotaxis. Our model is built on an off-lattice spherical biased random walk in 3-dimensional space, an extension of previous conventional deterministic 2-dimensional models. The sperm's type of movement is decided based on a comparison of the current and previous chemoattractant concentration which can be used to see whether it is approaching the egg. From the statistical analysis of the simulation results, we find that chemotaxis is an effective mechanism to increase the number of sperm reaching the egg.
72

The Effects of Sleep on an Emotional Memory Trade-off

Chen, Jennifer January 2010 (has links)
Thesis advisor: Elizabeth Kensinger / Thesis advisor: Katherine Mickley / Current research suggests that viewing complex scenes composed of a background and a negative, centralized image results in an emotion-induced memory trade-off. This trade-off is often characterized by high rates of memory accuracy for negative central images at the expense of a neutral background. In the present study, I explored whether the same trade-off effect is present for positive emotional stimuli. Therefore, when viewing complex scenes composed of a background and a positive central image, do people tend to remember the positive image more than they do the background? I examined two related research questions: (1) will positive scene components elicit an emotional memory trade-off effect? and (2) how does the passage of time, with and without sleep, influence positive scene components in comparison to negative scene components? Participants were separated into a sleep group and a wake group. The experiment consisted of two parts: the first was a viewing of 90 compound scenes and the second included a memory recognition test. Although the trade-off effect was present for negative valence items as well as positive objects, no main group effect was found. In other words, the emotional memory trade-off effect was not enhanced with sleep. / Thesis (BA) — Boston College, 2010. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Psychology Honors Program. / Discipline: Psychology.
73

From lab to market : early-stage business models for the commercialisation of university technology in the cleantech industry

Moktar, Zurina January 2018 (has links)
Over the years, scholarly interest in the role of business models to unlock the value of latent technology has increased. It is argued that the commercialisation of new technology requires business models that respond to a myriad of challenges and market needs. However, limited attention has been paid to understand how early-stage business models are developed to commercialise new university technology. Specifically, there are limited studies scrutinising the early-stage business models developed by University Spin-Offs (USOs), despite the fact that these are breeding grounds for new technology with commercial potential. Therefore, this thesis examines how USOs develop early-stage business models to commercialise new technology for the cleantech industry. To achieve this, an in-depth case study of four cleantech USOs at the University of Cambridge in the United Kingdom was performed. Sixty interviews with multiple stakeholders were conducted, and effectual logic and the concept of opportunity creation were adopted to inform the investigation. The findings, presented in a conceptual framework, suggest that USOs develop early-stage business models through three interlocking mechanisms. First, value is created through flow-field control, which is achieved by taking active control over a firm's resources and capabilities. Second, value is captured through pragmatic kinesis, defined as being sensible when moving towards profit. Third, value network is managed through deliberate temperament, which is used to align stakeholders' expectations. Along with these findings, the thesis also advances COPE principles (i.e. take control, create opportunities, forge partnerships and embrace contingencies) as parameters for the development of early-stage business models. The empirical evidence offers a critical logical shift in our understanding of early-stage business models development for commercialising university technology in the cleantech industry. The conceptual framework responds to scholarly inquiries to improve the theoretical grounding and construct clarity of business models. The thesis also informs policymakers about the pitfalls and opportunities associated with new technology commercialisation in the cleantech industry, where uncertainties are ubiquitous.
74

Concepção e simulação de célula robotizada para operações de acabamento

Barbosa, João Pedro Marques January 2010 (has links)
Tese de mestrado integrado. Engenharia Mecânica (Opção de Automação). Faculdade de Engenharia. Universidade do Porto. 2010
75

Ensino rápido de células de quinagem ADIRA

Coelho, Daniel Alves January 2011 (has links)
Versão final / Tese de mestrado integrado. Engenharia Mecânica. Universidade do Porto. Faculdade de Engenharia. 2011
76

On-Campus and Off-Campus Students' Ratings of Instruction and Courses

Saeki, Noriko 01 May 2003 (has links)
The associations of student ratings of instruction and courses (SRIC) with noninstructional variables (e.g., class size, expected grade) were examined in three instructional delivery groups--on-campus , off-campus face-to-face , and distance education courses. Factor analysis of SRIC from a 20-item form yielded two highly correlated factors , which differed somewhat across the groups ("Course " and "Instruction"; "Course/Instruction" and "Interaction Opportunities /Instructor Availability"; "Course/Instruction" and "Interaction Opportunities/Helpfulness"). The only educationally significant(r2 > .05) zero-order correlations were between SRIC total scores and expected grade, and were positive in all three groups(r2 = .07, .08, .06). In multiple regression analyses, 9%, 11 %, and 15% of the variance in SRIC for the three groups was explained by the entire set of noninstructional variables. Unique indices were consistent with the finding that expected grade was the only noninstructional variable with an educationally significant relationship with SRIC. In a separate study, SRIC and the instructor's social presence in host- and remote-site groups were investigated. Remote-site students rated course management lower, on average, than host-site students did, and educationally significant, positive relationships were found between social presence scores and the ratings on four SRIC categories. In addition , remote-site students at smaller sites tended to rate instruction and course satisfaction, as well as the instructor's social presence, higher than students at larger sites. In an additional investigation, students' ratings of teacher immediacy and reports of teacher-student interaction in distance education courses were analyzed. Host-site students tended to rate teacher immediacy higher than remote-site students did, and the negative association of site size with nonverbal teacher immediacy scores was educationally significant for host sites. Host-site students also tended to report more interaction with their instructors than remote-site students did, and mean reported interaction with the instructor was associated positively with site size and ratings of teacher immediacy. Based on the differing SRIC factorial structures for on-campus and off-campus students, the identification of distance-education-specific noninstructional variables, problems with obtaining SRIC from students in on-line courses, and evidence on the noninstructional-variable-related theory of teacher immediacy, suggestions were made for future research on student satisfaction and perceptions of teaching effectiveness in distance education.
77

Off-gas Nitrous Oxide monitoring for nitrification aeration control

Sivret, Eric Claude, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Effective control of nitrification processes employed at municipal wastewater treatment plants is essential for maintaining process reliability and minimizing environmental impacts and operating costs. While a range of process control strategies are available, they share a dependence on invasive liquid phase monitoring and are based on a periphery understanding of the metabolic status of the processes being controlled. Utilization of off-gas nitrous oxide (N2O) monitoring as a real-time indicator of the process metabolic status is a novel process control concept with the potential to address these concerns. This thesis details the development and evaluation of an off-gas N2O stress response based control technique. Examination of the stress response relationship demonstrated that it met the majority of the criteria of interest for process control. A simple feedback aeration control strategy was developed and evaluated through process simulation to determine the feasibility of implementation, cost effectiveness and associated environmental benefits. The off-gas N2O based control strategy provided better matching between aeration supply and metabolic demand, allowing the process to be maintained at the desired operating setpoints and avert nitrification failure. Performance was demonstrated to be similar to dissolved oxygen based feedback aeration control, although slightly more efficient at reduced dissolved oxygen concentrations. A technical, economic and environmental evaluation indicated that aeration control based on non-invasive off-gas N2O monitoring is technically feasible and has the potential to offer significant environmental and economic benefits including reductions in operating costs and process capital investment, as well as improved effluent compliance and reductions in emissions of gaseous pollutants including greenhouse gases. Overall, while off-gas N2O monitoring based aeration control techniques have the potential to provide significant economic and environmental benefits, a number of research questions remain to be answered. Future work in the form of long-term field trials is required to address these issues and allow quantification of economic and environmental benefits.
78

The contribution of cultural studies to right of publicity laws: evocative identification, associative appropriation and political recoding

Tan, David January 2010 (has links)
Celebrity sells. The right of publicity, broadly defined as the inherent right of every individual to control the commercial use of his or her identity, has been well-established in the United States (US) for over fifty years. It protects the associative value that one brings to products and services, and is invoked mainly by celebrities to prevent unauthorised commercial uses of their persona. / There is a wealth of legal literature in the US that discusses a broad range of issues from justifications for the right of publicity to its interaction with freedom of speech under the First Amendment. However, very few contributions have studied the connections between cultural practices and the right of publicity in depth. This dissertation draws on insights pertinent to aspects of right of publicity laws in its evaluation of how the cultural studies literature may contribute to doctrinal development. The usefulness of cultural studies in this inquiry rests in its examination of the roles and meanings of celebrities in contemporary society. / This thesis demonstrates how an appreciation of the production, circulation and consumption of the celebrity personality can be incorporated into an analytical framework. It argues that what we generally call ‘celebrity’ is a collective product of the celebrity individual, the audience and the cultural producers. Two exemplary insights are explored. The first insight on the definition of the contemporary celebrity based on well-knownness provides the impetus for the legal protection of the commercial value of identity. The second insight about the celebrity’s function as a cultural sign representing majoritarian ideals has important implications both for contemporary consumption and identity politics. It will be shown how these insights support the concepts of evocative identification, associative appropriation and political recoding, all contributing to a more nuanced understanding of three key elements of a typical publicity claim. As celebrities in other common law jurisdictions like the United Kingdom and Australia rely on the passing off action to seek redress for unauthorised commercial uses of their identity, the relevance of these concepts to passing off is also examined. / The findings indicate that insights from cultural studies on the celebrity phenomenon can support both an expansive interpretation of identification in a publicity claim and, at the same time, a more restrictive application of the requirement of commercial appropriation. The dissertation also demonstrates how treating ideological codings of the celebrity persona as political speech can influence the articulation of the First Amendment defence. In addition, these cultural insights have similar relevance to passing off laws, supporting a broad interpretation of goodwill and damage, and a standard of impressionistic association based on the notion of affective transfer as sufficient to constitute misleading conduct. / In conclusion, this dissertation establishes that, far from being merely a theoretical discipline concerned with semiotic codings and the politics of power and identity, cultural studies provides a pragmatic framework for judges, scholars and lawyers to further their understanding of the extra-legal issues relating to the laws protecting the commercial value of the celebrity personality.
79

Ger olika temperaturförhållanden ¨trade off¨- effekter mellan tillväxt och exokutikulans tjocklek hos Gammarus pulex? En pilotstudie

Holmgen, Jonas January 2007 (has links)
<p>I rinnande vatten, så som bäckar och åar, har Gammarus pulex en viktig ställning i näringsväven. Arten bidrar till att bryta ner organiskt material och göra energin i detta tillgänglig för andra organismer. G. pulex är dessutom en viktig föda för ett stort antal predatorer. Flera studier visar att G. pulex reagerar på olika temperaturer. Tillväxthastighet, livslängd, reproduktion, aktivitet och syreförbrukning är exempel på karaktärer som påverkas av temperaturen. Ingen studie har tidigare behandlat om anläggningen av exokutikula påverkas av temperaturen. En höjd temperatur ökar tillväxthastigheten och detta skulle kunna ge minskade resurser till generering av exokutikula, såkallad ”trade off”. Min studie syftar till att undersöka hur G. pulex tvingas fördela sina resurser mellan tillväxt och exokutikulans tjocklek i förhållande till förändrade temperaturförhållande. Till undersökningen användes 80 djur från två naturliga system med en genomsnittlig temperaturskillnad på 1,9ºC. Säsongsvariation mellan höst och vinter studerades utifrån samma lokaler. Exokutikulans tjocklek mättes och kroppslängden användes som storleksreferens. Statistisk analys gjordes av kvoten exokutikulatjocklek/kroppslängd och ingen signifikant skillnad hittades mellan de olika grupperna. Denna studie visar att ingen ”trade off” finns mellan exokutikulans tjocklek och tillväxt hos G. pulex, varken i de två systemen, eller p.g.a. säsongsvariation, höst och vinter. Detta kan bero på Amfipoders möjligheter att återanvända kalcium för uppbyggnad av en ny exokutikula samt eventuell god tillgång på resurser. Dessutom ger en höjd metabolism vid ökad temperatur ökade möjligheter till en snabb generering av en ny exokutikula. Vidare studier bör göras i både naturliga och artificiella miljöer för att vidare undersöka en eventuell ”trade off” mellan tillväxt och exokutikula.</p>
80

The Influence of Geometry on the Performance of Catalytic Converter

Najafi Marghmaleki, Amirhassan 11 1900 (has links)
In this thesis, the development and use of a transient heterogeneous 2D model for monolithic catalytic converter is presented. Study on the cold flow hydrodynamics, temperature effect and CO conversion and light off behaviour of different models is developed. Different models are studied based on different parameters such as monolith brick CPSI configuration, size of the converter, inlet cone sizing and inlet velocity of the converter. The results for both steady state and transient modes are presented in detail. It is shown that monolith brick CPSI has a significant effect on pressure drop and light-off behaviour of the converter. Also, converter size has a major effect on the performance of a converter. Inlet cone sizing showed to have a significant effect on the hydrodynamics of the converter but it did not have a major effect on light-off behaviour of the converter. / Chemical Engineering

Page generated in 0.0446 seconds