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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.
921

Development of an impact assessment tool for demolition

Kunieda, Yoichiro January 2017 (has links)
Currently in the field of demolition, which generates most of the waste in the construction industry, the treatment of waste largely relies on landfill or degraded recycling, which leads to significant consumption of natural resource and energy and a shortage of landfill site. In order to improve the inefficiency of demolition waste recovery, “to suggest improvements in the environmental impact of the demolition industry in UK” was set as the aim of the present research. After the identification of few opportunities for communication between demolishers and constructers in the current social system, a collaboration support system between these two stakeholders called ‘Demolition Project Mapping’ (DPM) system was suggested. In the system, the impact evaluation tool developed in the 4D-CAD software is applied to the demolition project simulation. This tool allows the users to dynamically simulate the impact of project planning which can be designed in the tool. In the pilot study, the simulation result shows the large potential to reduce the impact (e.g. 28% for the cost) by the tool application.
922

Development of a Methodology for Creating Families of Parts

Marr, Gregory M. 14 May 1999 (has links)
The purpose of this thesis was to develop methodologies and procedures for the construction and use of CAD part families. This project uses the software CADDS5 created by Computervision, Inc., and its "Family of Parts" module. This software allows the creation of an entire family of similar parts using a single parametric master model and a text file containing the necessary parameters for each member of the family. CADDS5 users at Raytheon were surveyed to determine how they use standard parts, what types of standard parts are used, and typical modeling strategies. A set of criteria were developed to determine which groups of parts would be good candidates to be used as test cases. Four test cases were used to develop the methodology or procedure for the creation of families of parts. In addition, efficient use of these part families required the development of a set of search engines to allow the users to find parts more easily, and a parts server to generate new family members. The Family of Parts software in CADDS5 serves as a starting point for the creation of a usable library of standard parts. However, it has a poor user interface and has no system for part management and database administration. This thesis has made up for several of these shortcomings, and has created the core of a working library that can be easily used by all of the designers without requiring detailed knowledge of the details behind the implementation. The methodology developed during this project provides the necessary information for designers to create the majority of standard parts in use at Raytheon. For those who want to expand the library, it has provided useful information that will help them create high-quality parts that will work well with this system.
923

Ferramenta para modelagem de sistemas de comunicação. / Tool for modeling communication systems.

Catalina Zapata 06 August 2007 (has links)
Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.
924

Inserção de células geradas automaticamente em um fluxo de projeto Standard Cell

Guimarães Júnior, Daniel Silva January 2016 (has links)
Este trabalho apresenta o desenvolvimento de um fluxo de projeto de circuitos digitais integrados, visando a incluir células geradas automaticamente pela ferramenta ASTRAN. Como parte integrante deste novo fluxo, desenvolveu-se uma nova técnica de comparação entre células, utilizando Redes Neurais Artificiais, para a modelagem das células ASTRAN, esta técnica se mostrou flexível ao se adaptar a diversos tipos de células e com resultados robustos tendo 5% de desvio padrão e 4% para o erro relativo. Também, foi criada uma ferramenta capaz de substituir células comerciais por células ASTRAN, tendo como objetivo melhorar as características de potência consumida e área utilizada pelo circuito, e por fim gerando um circuito misto composto de células comerciais feitas à mão e células ASTRAN geradas automaticamente. O foco principal deste trabalho encontra-se na integração do fluxo de geração de células geradas automaticamente a um fluxo de síntese comercial de circuitos digitais. Os resultados obtidos mostraram-se promissores, obtendo-se ganhos em redução de área e potência dos circuitos analisados. Em média os circuitos tiveram uma redução de 3,77% na potência consumida e 1,25% menos área utilizada. Com um acréscimo de 0,64% por parte do atraso total do circuito. / This work presents the development of a design flow for digital integrated circuits, including cells generated automatically by the ASTRAN tool. Moreover, a new technique, using Artificial Neural Networks, was developed to perform a comparison between two different cells, i.e. commercial and ASTRAN’s cell. This technique proved to be flexible when adapting to several types of cells and with robust results having 5% of standard deviation and 4% for relative error. Also, a new tool was developed, capable of performing cell replacement between ASTRAN and commercial cells, to improve power consumption an used area. Finally a mixed circuit composed of handmade commercial cells and cells automatically generated by ASTRAN was generated. A target was to mix an automatic cell synthesis tool with commercial synthesis tools dedicated to standard cells. Comparisons have shown that our approach was able to produce satisfactory results related area and power consumption. In average the circuits had a reduction of 3.77% in the power consumed and 1.25% less used area. With an increase of 0.64% due to the total delay of the circuit.
925

FRÅN STILLEBEN TILL MÖNSTER

BÄLTER BJURGERT, LOVISA January 2014 (has links)
Det finns sparsamt med litteratur om arbetet med draperade plagg ur en mönsterkonstruktörs synvinkel. Dessutom tar majoriteten av mönsterkonstruktionsundervisningen sällan upp drapering i ett tidigt stadie (om över huvud taget). Rapportens syfte är att undersöka hur en mönsterkonstruktör kan gå tillväga för att översätta draperade plagg till reproducerbara tvådimensionella mönster. Som underlag för studien har tre plagg draperade på docka av en extern handledare använts. Det första plagget är en vävd klänning, det andra en klänning i trikå och det tredje en quiltad väst. I originaldraperingarnas tyg markeras fästpunkter och eventuella skärningar noga, därefter monteras draperingen ned, delarna kalkeras av och toiler sys upp och provas på dockor och provpersoner i flera omgångar tills önskat resultat erhålls. De slutgiltiga mönsterdelarna digitaliseras in i programvaran Modaris (Lectra Systemes) där linjer finputsas och kontrollmäts och plaggen graderas. Studien visar hur en mer direkt förståelse för hur tyg och form påverkas av kroppen kan uppnås med hjälp av draperingsbaserad mönsterkonstruktion. Det behöver inte finnas en motsättning mellan de olika sätten att arbeta, eftersträvansvärt vore istället att mönster-konstruktörer behärskar så många tekniker som möjligt för att kunna nå ett bra slutresultat / Program: Designteknikerutbildningen
926

FRÅN STILLEBEN TILL MÖNSTER : En studie i översättandet av draperade plagg till tvådimensionella konstruktioner

BÄLTER BJURGERT, LOVISA January 2014 (has links)
Det finns sparsamt med litteratur om arbetet med draperade plagg ur en mönsterkonstruktörs synvinkel. Dessutom tar majoriteten av mönsterkonstruktionsundervisningen sällan upp drapering i ett tidigt stadie (om över huvud taget). Rapportens syfte är att undersöka hur en mönsterkonstruktör kan gå tillväga för att översätta draperade plagg till reproducerbara tvådimensionella mönster. Som underlag för studien har tre plagg draperade på docka av en extern handledare använts. Det första plagget är en vävd klänning, det andra en klänning i trikå och det tredje en quiltad väst. I originaldraperingarnas tyg markeras fästpunkter och eventuella skärningar noga, därefter monteras draperingen ned, delarna kalkeras av och toiler sys upp och provas på dockor och provpersoner i flera omgångar tills önskat resultat erhålls. De slutgiltiga mönsterdelarna digitaliseras in i programvaran Modaris (Lectra Systemes) där linjer finputsas och kontrollmäts och plaggen graderas. Studien visar hur en mer direkt förståelse för hur tyg och form påverkas av kroppen kan uppnås med hjälp av draperingsbaserad mönsterkonstruktion. Det behöver inte finnas en motsättning mellan de olika sätten att arbeta, eftersträvansvärt vore istället att mönster-konstruktörer behärskar så många tekniker som möjligt för att kunna nå ett bra slutresultat / Program: Designteknikerutbildningen
927

Accuracy and reliability of traditional measurement techniques for tooth widths and arch perimeter compared to CAD/CAM

Elmubarak, Mona Dr. January 2018 (has links)
Magister Scientiae Dentium - MSc(Dent) / BACKGROUND: Plaster models form an integral part of the traditional orthodontic records. They are necessary for diagnosis and treatment planning, case presentations as well as for the evaluation of treatment progress. The accuracy of the measurements taken for space assessment is crucial prior to treatment planning. The introduction of digital models overcomes some problems experienced with plaster models. Digital models have shown to be an acceptable alternative for plaster models. AIM: The aim of the study was to determine the accuracy of traditional measurement techniques when compared to the CAD/ CAM measurements in the assessment of tooth widths and arch perimeter from plaster models. METHOD: The mesio-distal tooth widths and arch perimeter of thirty archived plaster models were measured using a digital caliper to the nearest 0.01 mm and divider to the nearest 0.1 mm. Corresponding digital models were produced by scanning them with a CAD/CAM (InEos X5) and space analysis completed by measurements using InEos Blue software. Measurements were repeated after 1 week from the initial measurement. The methods were compared using descriptive analysis (mean difference and standard deviation). RESULTS: The operator reliability was high for digital models as well as the plaster models when the measurement tool was the digital caliper (analyzed using the Pearson correlation coefficient in the paired t-test). The mean values of tooth widths measurements of CAD/CAM, digital caliper and divider were 6.82 (±0.04), 6.94 (± 0.04) and 7.11 (± 0.04). There was a significant difference between the measurements made by the CAD/CAM and the divider. Additionally significant differences between the measurements by digital caliper and divider measurements (p < 0.05) were observed. No significant difference was found when comparing CAD/CAM to digital caliper. Positive correlation was displayed between CAD/CAM, digital caliper and the divider, but the measurements completed with the digital caliper had the highest correlation with the CAD/CAM. The difference was not significant between the aforementioned measurement tools (p > 0.05). Arch perimeter measurements showed no statistical significant difference between CAD/CAM, digital caliper and divider (p < 0.05). CONCLUSION: Archived plaster models stored as records can be converted to digital models as it will have the same accuracy of measurements. The value of doing a space analysis with the CAD/CAM system can be performed with similar reliability on the digital models as a caliper on plaster models.
928

IT-stöd För projektering och produktion av massivträhus / IT-support For planning and construction of solid woodhouse

Dahlqvist, Ida, Gabrielsson, Simon January 2008 (has links)
Detta examensarbete har arbetats fram under våren 2008 och dess syfte har varit att se hur man kan använda tre- och fyrdimensionella dataverktyg för att få en så effektiv montering av massivträstomme som möjligt för hus typ B1a på Valö Fyr. Inför skrivandet av denna rapport gjordes en litteraturstudie om trä, massivträelement och Building Information Model (BIM). Utifrån tvådimensionella (2D) ritningar från arkitekten modellerades ett komplett tredimensionellt (3D) hus av typ B1a på Valö Fyr. Sedan från konstruktörens ritningar gjordes en 3D- modell av massivträstommen. Denna modell blev sedan grunden för den fyrdimensionella (4D) visualiseringen för montaget av stommen. I 4D är tiden den fjärde dimensionen. För att göra 3D- modellerna användes Autodesk Revit och för 4D- visualiseringen Ceco Visual 2008. Att använda rätt 3D- och 4D- verktyg är viktigt för byggbranschen. En 3D-modell som använder BIM- tekniken gör att man kan inkludera så mycket mer än bara det synliga i modellen. Man kan göra olika listor och lagra information som man kan ha nytta av under projekteringen, produktionen och förvaltningen. I ett projekt av Valö Fyrs storlek kan man ha stor nytta av att använda 3D- och 4D- modeller. Man kan t ex upptäcka olika krockar i elementen i en 3D- modell och i förtid och med hjälp av 4D kontrollera att monteringen kommer att fungera. / <p>Uppsatsnivå: C</p>
929

Koncept på ett hydrauliskt mothåll / Concept of a hydraulic counter hold

Sharef, Hajan, Potari, Marek January 2016 (has links)
New technology in the automotive industry is the key to success. Therefore, it is appreciated when people come with new design ways to solve problems. This leads to innovation in the automotive industry that will lead to better and more environmentally friendly cars. This report presents a concept on a pushing counter lever spring which provides the same characteristics of force curve as a diaphragm spring in a pressure plate of a car has. The mechanism is to be used for long-term testing and evaluating clutch pedals. The work describes the development process and the manufacture of a prototype. The program Creo (CAD / 3D) is largely used to construct the components. As are the subprograms Mechanism Design and Simulate to simulate the movement and loads. Excel is a great help at the theoretical calculation of the mechanism and to evaluate the theory behind the concept. The result shows how to simulate a diaphragm spring in the pressure plate in a car for long-term testing of clutch pedals. The goal is to accurately mimic the force curve of a diaphragm spring, in order to design better pedals, and thus reduce the weight on the pedals to in turn reduce fuel consumption to protect the environment is one of the most important factors of all in the automotive industry.
930

Caracterização de blocos sinterizados à base de CoCrMo visando a obtenção de próteses odontológicas por fresagem CAD/CAM / Characterization of Co-Cr-Mo sintered blocks in order to obtain dental prostheses by prototyping CAD/CAM

Bruno Xavier de Freitas 19 December 2016 (has links)
Estudou-se a caracterização de blocos sinterizados à base de Co-Cr-Mo visando a obtenção de próteses odontológicas por fresagem CAD/CAM. O processo de sinterização foi estudado e ocorreu através do transporte difusional de massa e calor no estado sólido, denominado sinterização no estado sólido. Esse fenômeno produz uma forte união entre as partículas devido ao transporte de massa, em escala atômica, sob condições controladas de tempo, temperatura e atmosfera. Foram realizadas sinterizações interrompidas a 800, 1000, 1200 e 1300°C nos tempos de 15 minutos, 1 hora e 4 horas. A liga foi caracterizada nas condições recebida e sinterizadas em termos de composição química, propriedades mecânicas e caracterização microestrutural. Para isto, utilizou-se fluorescência de raios X, dilatometria, ensaios de Arquimedes, ensaios de dureza, ensaios de compressão, microscopia eletrônica de varredura (MEV), microscopia óptica e microanálise eletrônica dispersiva (EDS). Os resultados composicionais indicam que a liga se encontrava dentro da faixa de composição química estabelecida pelo manual do fabricante e pela norma ASTM 1537. As partículas analisadas na condição pré-sinterizada exibiram formato esférico, indicando uma provável utilização de pós atomizados. A estimativa do levantamento da distribuição do tamanho das partículas foi realizado utilizando o programa de computador ImageJ, e a distribuição foi caracterizada como assimétrica positiva. O material no estado recebido se apresentou monofásico. A fase presente encontrada foi ?Co com estrutura cristalina CFC. Em contrapartida, as amostras sinterizadas apresentaram porções de fase ?Co, com estrutura cristalina hexagonal, fase esta formada a partir da transformação ?Co <-> ?Co, na qual, a energia armazenada na forma de defeitos é a força motriz da transformação. E sugere que a transformação ocorreu durante resfriamento. A amostra sinterizada por quatro horas em 1200°C apresentou-se no estágio final de sinterização, dado que os poros encontrados tinham aspecto arredondado e com densificação maior que 90%. Os resultados de compressão indicam tensão média de ruptura de 2523 ± 168 MPa. / This work studied the characterization of Co-Cr-Mo sintered blocks in order to obtain dental prosthesis by prototyping CAD/CAM. The sintering process was studied through diffusional mass transport in solid state, termed solid state sintering. This phenomenon produces a strong bond between the particles due to mass transport, at the atomic scale, under controlled conditions of time, temperature and atmosphere. The interrupted sintering was performed at 800, 1000, 1200 and 1300 ° C in times to 15 minutes, 1 hour and 4 hours. The alloy was characterized in conditions as received and sintered in terms of chemical composition, mechanical properties and microstructural characterization. For this, we used X-ray fluorescence, dilatometry, Archimedes tests, hardness tests, compression tests, scanning electron microscopy (SEM), optical microscopy and dispersive electron microanalysis (EDS). The results indicate that the alloy was within the chemical composition range established by the manufacturer and ASTM 1537. The particles analyzed in the pre-sintered condition showed spherical shape, indicating a likely use of atomized powders. The estimate of the particle size distribution was performed using ImageJ software, and the distribution is characterized as positive asymmetric. The samples in the received state were monophasic. This phase was found ?Co with FCC crystal structure. On the order hand, the sintered samples showed ?Co phase portions with hexagonal crystal structure, phase formed from the transformation ?Co <-> ?Co, in which the energy stored in the form of defects is the driving force of transformation and suggests that transformation occurred during the cooling. Sample sintered during four hours at 1200°C was in the final stages of sintering, since the pores were found aspect rounded and densification above 90%. The compression results indicate rupture stress at 2523 ± 168 MPa.

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