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  • 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.
1

Development of virtual laboratory as an educationalresearch tool in food processing

Chi, Minli, 1965- January 2005 (has links)
Personal computers (PC) and high level programming techniques have been developing so rapidly during last decade leading to new and exciting opportunities in the field of education. The purpose of this research was to develop food processing virtual labs as efficient teaching and study tools for food processing courses using user-friendly computer languages (VC++, MFC and OpenGL). A 3D graphic technique was employed in this study as a specific objective to generate 3D graphics in the visualization mode. / According to functionalities, virtual labs were designed for three basic simulations: (1) Calculation simulations, which perform various calculations related to food processing. These simulations help users to remember and understand the formula used in process calculations. Several simple concept calculations were included: conduction heat transfer in steady state through individual and composite slabs; two-component mass balance systems, Pearson rule applications; freezing and thawing time calculations; (2) Animation simulations, which are aimed to visualize processing scenarios for different physical phenomena or working principles. Included in these simulations were: conduction heat transfer through single and multiple walls under steady state; mixing processes involving two and three component systems and Pearson rule concept; freezing and thawing processes through slab, cylinder, and sphere, the three regular shapes, agitation thermal processing modes which include axial agitation and end-over-end agitation in rotational retort; (3) Virtual equipment simulations, which are aimed to dynamically simulate a real operating environment and to demonstrate equipment working principle, internal structure, and operating procedures. The simulated equipment include a horizontal retort used in thermal processing and a high pressure processing equipment used in non-thermal processing. / The food processing virtual labs provide a new way in teaching and learning, with no risk, time or place limitations, and are cost effective. The simulated scenarios and equipment can be used as teaching tools in food processing courses, which provide an efficient way to the instructor/assistant. Instructor/assistant can dynamically and repeatedly demonstrate the operating process for the simulated equipment in a vivid and interested manner. Also students can get intuitive understanding by viewing these simulations. Computers are the waves of the future; however, traditional learning techniques should not be forgotten.* / *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Windows 95 or higher.
2

Methods for Composing Tradeoff Studies under Uncertainty

Bily, Christopher 2012 August 1900 (has links)
Tradeoff studies are a common part of engineering practice. Designers conduct tradeoff studies in order to improve their understanding of how various design considerations relate to one another. Generally a tradeoff study involves a systematic multi-criteria evaluation of various alternatives for a particular system or subsystem. After evaluating these alternatives, designers eliminate those that perform poorly under the given criteria and explore more carefully those that remain. The capability to compose preexisting tradeoff studies is advantageous to the designers of engineered systems, such as aircraft, military equipment, and automobiles. Such systems are comprised of many subsystems for which prior tradeoff studies may exist. System designers conceivably could explore system-level tradeoffs more quickly by leveraging this knowledge. For example, automotive systems engineers could combine tradeoff studies from the engine and transmission subsystems quickly to produce a comprehensive tradeoff study for the power train. This level of knowledge reuse is in keeping with good systems engineering practice. However, existing procedures for generating tradeoff studies under uncertainty involve assumptions that preclude engineers from composing them in a mathematically rigorous way. In uncertain problems, designers can eliminate inferior alternatives using stochastic dominance, which compares the probability distributions defined in the design criteria space. Although this is well-founded mathematically, the procedure can be computationally expensive because it typically entails a sampling-based uncertainty propagation method for each alternative being considered. This thesis describes two novel extensions that permit engineers to compose preexisting subsystem-level tradeoff studies under uncertainty into mathematically valid system-level tradeoff studies and efficiently eliminate inferior alternatives through intelligent sampling. The approaches are based on three key ideas: the use of stochastic dominance methods to enable the tradeoff evaluation when the design criteria are uncertain, the use of parameterized efficient sets to enable reuse and composition of subsystem-level tradeoff studies, and the use of statistical tests in dominance testing to reduce the number of behavioral model evaluations. The approaches are demonstrated in the context of a tradeoff study for a motor vehicle.
3

Development of virtual laboratory as an educational research tool in food processing

Chi, Minli, 1965- January 2005 (has links)
No description available.
4

Design, Development and Characterization of a Wrap Spring Clutch/Brake Mechanism as a Knee Joint for a Hybrid Exoskeleton

Subra Mani, Vishnu Aishwaryan 16 May 2020 (has links)
Evolution had played a significant role in structuring on how humans stand, walk or run. The nervous system plays a major role in the control of locomotion and injuries to the system can lead to gait abnormalities or disabilities. A Spinal Cord Injury (SCI) causes lack of signal communication between the central nervous system and the muscle fibers leading to deprived or no activation of the muscles thus resulting in paraplegia or quadriplegia. Over the past decade wearable robotics and exoskeletons have been gaining outstanding recognition in the field of medical, assistive and augmentative robotics and have led to numerous new innovative mechanisms in the mechanical engineering field. Due to fast paced research activities, the critical importance and performance of mechanisms such as wrap spring clutch/brake,Wafer Disc brakes are overlooked or used ineffectively. So, researchers tend to create new actuators from scratch and have limited their use of previously available resources, which has prevented us to explore the potential of these devices.The research presented focuses on developing a mechanism (“A Wrap Spring Clutch/Brake Mechanism”) from scratch using a trade study approach. This thesis addresses the fundamental relationship between coefficient of friction, interference, spring diameter and the holding torque of the mechanism using analytical, testing and simulation results. The human biomechanical data during ground level walking was used as design targets to develop the mathematical model of the system. Data from the testing stated that these targeted goals have been achieved by the design. This mechanism is used as a Knee Joint for the Hybrid EXoskeleton (HEX) GEN-1 project which is developed at the Automation and Interventional Medicine (AIM) Robotics Research Laboratory to rehabilitate the SCI.
5

Effectiveness of a program-specific assessment instrument for a department of clothing and textiles

Giddings, Valerie L. 28 July 2008 (has links)
The purposes of this study were (1) to determine the validity, reliability, and item quality of a program-specific, assessment instrument designed to measure student mastery of core knowledge in the discipline, (2) to evaluate the effectiveness of the instrument for determining student outcomes from the value-added perspective, and (3) to determine whether performance on the instrument and other measures of achievement was affected by student involvement characteristics. The instrument contained 100 multiple-choice items relating to five core courses. For portions of the study, the instrument was divided into five subtests and administered as a pretest on the first day of classes in the five core courses and as a post test on the last day of classes. The instrument in its full form was administered to upper class clothing and textiles majors and to under class clothing and textiles majors. Interviews related to the instrument were conducted with a subset of students who had taken the subtests and the full exam and with faculty who taught the courses. The split-half and the KR-20 reliability estimates for internal consistency of the full test were above .70. The increase in student performance from pretest to posttest and the correlation between information obtained from the interviews with the results of the item analyses demonstrated the instrument's content validity. The significant difference between scores received by upper class majors and scores received by underclass majors on the instrument, and the correlations between course grades with scores on the instrument and final exam grades with scores on the instrument demonstrated the construct validity of the instrument. The ability of the instrument to measure value-added knowledge was ascertained by the increase in student performance from pretest to post test. Further data analyses revealed a pattern regarding factors which affect student achievement. Student involvement in organizations and employment had a positive and negative effect on various measures of student achievement. Although the validity and reliability of the instrument were demonstrated, improvements in item quality and representation of course objectives on the core knowledge exam are needed. / Ph. D.
6

O conceito de turismo sexual na perspectiva de sua inserção como objeto de estudo na graduação em Turismo

Marinho, Marcela Ferreira 15 September 2010 (has links)
Esta pesquisa visa contribuir para a discussão/(re)construção do conceito de turismo sexual, na perspectiva de abordá-lo pedagogicamente na formação superior em turismo. O suporte teórico para as reflexões foi buscado na Teoria das Representações Sociais e na teoria psicanalítica freudiana sobre sexualidade. Metodologicamente, a análise do discurso pautou-se pelos conceitos de enunciação, de polifonia e heterogeneidade, respectivamente de Bakhtin, Ducrot e Authier-Revuz, assim como por procedimentos analíticos da Fenomenologia-Hermenêutica, conforme Panosso Netto. Foram analisadas matérias dos jornais Gazeta de Alagoas/AL e Correio do Povo/RS versando sobre turismo e respostas de alunos e professores de graduação em Turismo desses estados, a quem foi perguntado ´Como você define turismo sexual?´. Relativamente às representações sociais, as matérias jornalísticas indicaram predomínio do aspecto de ilicitude do fenômeno, sinalizando compartilhamento simbólico do turismo sexual, centrado, metonimicamente, na exploração sexual de menores, como problema social, e sobre a busca por satisfação sexual. Do ponto de vista da sexualidade, os jornais, representantes da mídia, portam o discurso freudiano fundante da organização dos grupos sociais, ou seja, o discurso fundante de acesso à cultura, de reconhecimento do interdito que viabiliza o social, impondo como necessária a repressão da sexualidade. O mesmo se aplica aos alunos e professores quando o polo definitório de turismo sexual recai sobre a perversão da sexualidade, aquele assumindo o discurso fundante e estes, dele sendo portadores. Outro polo definitório incide sobre a satisfação do desejo sexual, o que poderia estar refletindo a ―voz científica‖ da Academia, de aceitação do homem em sua natureza bio-psicossocial, embora não haja referência a segmentos turísticos em cuja denominação não aparece o termo ―sexual‖ inseridas socialmente no âmbito da normalidade. Confirma-se assim a complexidade conceitual do fenômeno e a necessidade de discutí-lo, seja, avançando na compreensão de tabus em relação ao termo, seja reconhecendo a existência de um lugar sadio e adequado para atender a demanda do turista na sua busca humana do prazer (não ilícito), da satisfação erótica. Nessa direção, cabe ao profissional do turismo reconhecer o desejo de natureza sexual do turista como um desejo humano, que não se constitui perverso ou ilícito a priori. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-04T18:58:30Z No. of bitstreams: 1 Dissertacao Marcela Ferreira Marinho.pdf: 7541696 bytes, checksum: 15daf44a2463fc95b2e131ab165e8626 (MD5) / Made available in DSpace on 2014-06-04T18:58:30Z (GMT). No. of bitstreams: 1 Dissertacao Marcela Ferreira Marinho.pdf: 7541696 bytes, checksum: 15daf44a2463fc95b2e131ab165e8626 (MD5)
7

O conceito de turismo sexual na perspectiva de sua inserção como objeto de estudo na graduação em Turismo

Marinho, Marcela Ferreira 15 September 2010 (has links)
Esta pesquisa visa contribuir para a discussão/(re)construção do conceito de turismo sexual, na perspectiva de abordá-lo pedagogicamente na formação superior em turismo. O suporte teórico para as reflexões foi buscado na Teoria das Representações Sociais e na teoria psicanalítica freudiana sobre sexualidade. Metodologicamente, a análise do discurso pautou-se pelos conceitos de enunciação, de polifonia e heterogeneidade, respectivamente de Bakhtin, Ducrot e Authier-Revuz, assim como por procedimentos analíticos da Fenomenologia-Hermenêutica, conforme Panosso Netto. Foram analisadas matérias dos jornais Gazeta de Alagoas/AL e Correio do Povo/RS versando sobre turismo e respostas de alunos e professores de graduação em Turismo desses estados, a quem foi perguntado ´Como você define turismo sexual?´. Relativamente às representações sociais, as matérias jornalísticas indicaram predomínio do aspecto de ilicitude do fenômeno, sinalizando compartilhamento simbólico do turismo sexual, centrado, metonimicamente, na exploração sexual de menores, como problema social, e sobre a busca por satisfação sexual. Do ponto de vista da sexualidade, os jornais, representantes da mídia, portam o discurso freudiano fundante da organização dos grupos sociais, ou seja, o discurso fundante de acesso à cultura, de reconhecimento do interdito que viabiliza o social, impondo como necessária a repressão da sexualidade. O mesmo se aplica aos alunos e professores quando o polo definitório de turismo sexual recai sobre a perversão da sexualidade, aquele assumindo o discurso fundante e estes, dele sendo portadores. Outro polo definitório incide sobre a satisfação do desejo sexual, o que poderia estar refletindo a ―voz científica‖ da Academia, de aceitação do homem em sua natureza bio-psicossocial, embora não haja referência a segmentos turísticos em cuja denominação não aparece o termo ―sexual‖ inseridas socialmente no âmbito da normalidade. Confirma-se assim a complexidade conceitual do fenômeno e a necessidade de discutí-lo, seja, avançando na compreensão de tabus em relação ao termo, seja reconhecendo a existência de um lugar sadio e adequado para atender a demanda do turista na sua busca humana do prazer (não ilícito), da satisfação erótica. Nessa direção, cabe ao profissional do turismo reconhecer o desejo de natureza sexual do turista como um desejo humano, que não se constitui perverso ou ilícito a priori.
8

The application of systems engineering to a Space-based Solar Power Technology Demonstration Mission

Chemouni Bach, Julien 07 June 2012 (has links)
This thesis presents an end-to-end example of systems engineering through the development of a Space-based Solar Power Satellite (SSPS) technology demonstration mission. As part of a higher education effort by NASA to promote systems engineering in the undergraduate classroom, the purpose of this thesis is to provide an educational resource for faculty and students. NASA systems engineering processes are tailored and applied to the development of a conceptual mission in order to demonstrate the role of systems engineering in the definition of an aerospace mission. The motivation for choosing the SSPS concept is two fold. First, as a renewable energy concept, space-based solar power is a relevant topic in today's world. Second, previous SSPS studies have been largely focused on developing full-scale concepts and lack a formalized systems engineering approach. The development of an SSPS technology demonstration mission allows for an emphasis on determining mission, and overall concept, feasibility in terms of technical needs and risks. These are assessed through a formalized systems engineering approach that is defined as an early concept or feasibility study, typical of Pre-Phase A activities. An architecture is developed from a mission scope, involving the following trade studies: power beam type, power beam frequency, transmitter type, solar array, and satellite orbit. Then, a system hierarchy, interfaces, and requirements are constructed, and cost and risk analysis are performed. The results indicate that the SSPS concept is still technologically immature and further concept studies and analyses are required before it can be implemented even at the technology demonstration level. This effort should be largely focused on raising the technological maturity of some key systems, including structure, deployment mechanisms, power management and distribution, and thermal systems. These results, and the process of reaching them, thus demonstrate the importance and value of systems engineering in determining mission feasibility early on in the project lifecycle. / text
9

Converting an Automobile Engine to an Aircraft Engine / Konvertera en bilmotor till en flygmotor

Kronberg, Gabriel January 2022 (has links)
This project evaluates the opportunity to convert a three-cylinder automobile piston engine (the Tiny Friendly Giant) to an aircraft engine from an environmental and practical point of view. The problem of increased emissions from aviation calls for technical and socioeconomic solutions, which is the reason why this report is written. The main goals are to choose the best fuel for the piston engine in aviation, as well as to study emissions, engine cooling and practical challenges with conversion. The structure resembles a feasibility study where the problem is solved using literature in a trade study, together with emission estimations using The Greenhouse gases, Regulated Emissions, and Energy use in Technologies Model framework and Boeing Fuel Flow Method 2. An estimation for engine cooling is done using a semiemprical method from Lycoming, showing air cooling can be sufficient for the Tiny Friendly Giant in aviation. The results furthermore show that none of the alternative automobile fuels are appropriate for use in aviation and that alternative pathways to jet fuel are more suited for high altitude. The conclusion is thus that the engine should be converted to jet fuel compatibility. To avoid large turning moment fluctuations, two-stroke can be applied. Conversion and use of the engine in aviation is not considered to be feasible because of practical limitations - instead the study concludes designing a new engine from scratch is easier and most likely quicker. The study shows that reducing carbon dioxide emissions also lead to reductions in water and sulfur- and nitrous oxides. However, the same mitigation strategy leads to increase in carbon monoxide and hydrocarbons. In general, the conclusion is that alternative fuels can significantly reduce aircraft emissions. / Detta examensarbete utvärderar möjligheten att konvertera en trecylindrig bilkolvmotor (Tiny Friendly Giant motorn) till en flygplansmotor från en miljömässig och praktisk synvinkel. Problemet med ökade utsläpp från flyget kräver tekniska och socioekonomiska lösningar, vilket är anledningen till att detta arbete är genomfört. De största målen går ut på välja det bästa bränslet för kolvmotorn inom flyget, samt att studera utsläpp, motorkylning och praktiska utmaningar med konvertering. Strukturen liknar en förstudie där problemet löses med hjälp av litteratur i en paramterstudie, tillsammans med utsläppsuppskattningar med hjälp av The Greenhouse gases, Regulated Emissions, and Energy use in Technologies Model ramverket och Boeing Fuel Flow Method 2. En uppskattning för motorkylning är beräknat med en semiemprisk metod från Lycoming, som visar att luftkylning vara tillräckligt för Tiny Friendly Giant motorn inom flyg. Resultaten visar vidare att inget av de alternativa bilbränslena är lämpliga för användning inom flyget och att alternativa vägar till flygbränsle är mer lämpat för hög höjd. Slutsatsen är att motorn bör konverteras till flygbränslekompatibilitet. För att undvika stora vridmomentfluktuationer kan tvåtakt användas. Konvertering och användning av motorn inom flyget anses inte vara genomförbart på grund av praktiska begränsningar - istället drar studien slutsatsen att design av en ny motor från grunden är enklare och med största sannolikhet snabbare. Studien visar att minskade koldioxidutsläpp också leder till minskningar av vatten och svavel- och dikväveoxider. Samma strategi leder dock till en ökning av kolmonoxid och kolväten. Generellt sett är slutsatsen att alternativa bränslen avsevärt kan minska flygplanens utsläpp.
10

A risk-informed decision making framework accounting for early-phase conceptual design of complex systems

Van Bossuyt, Douglas L. 26 April 2012 (has links)
A gap exists in the methods used in industry and available in academia that prevents customers and engineers from having a voice when considering engineering risk appetite in the dynamic shaping of early-phase conceptual design trade study outcomes. Current methods used in Collaborative Design Centers either collect risk information after a conceptual design has been created, treat risk as an afterthought during the trade study process, or do not consider risk at all during the creation of conceptual designs. This dissertation proposes a risk-informed decision making framework that offers a new way to account for risk and make decisions based upon risk information within conceptual complex system design trade studies. A meaningful integration of the consideration of risk in trade studies is achieved in this framework thus elevating risk to the same level as other important system-level design parameters. Trade-offs based upon risk appetites of individuals are explicitly allowed under the framework, enabled by an engineering-specific psychometric risk survey that provides aspirational information to use in utility functions. This dissertation provides a novel framework and supporting methodologies for risk-informed design decisions and trades to be made that are based upon engineering risk appetites in conceptual design trade studies. / Graduation date: 2012

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