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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

Classification of Research and Applications in Feature Modeling and Computer Aided Process Planning

Kolli, Sam January 2004 (has links)
No description available.
2

Otimização de processos de usinagem em uma célula flexível de manufatura

Orlando Silveira Rocha, José January 2006 (has links)
Made available in DSpace on 2014-06-12T17:40:15Z (GMT). No. of bitstreams: 2 arquivo7611_1.pdf: 1747470 bytes, checksum: 9c89a3b7194ba1415869fb032c7330c5 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / Nos últimos anos, a globalização e a livre concorrência internacional dos mercados tem forçado as empresas a desenvolverem produtos com maior qualidade em um menor tempo de fabricação e custos cada vez mais baixos. As empresas, de uma forma geral, têm sido convocadas a se adaptarem a esta nova realidade como forma de garantir a sua sobrevivência. Para isto passaram a utilizar tecnologias de ponta na manufatura de seus produtos, que envolvem desde a concepção do produto até assistência pós-venda. No que se refere às empresas de manufatura por usinagem, uma etapa de grande importância na concepção de um produto é o planejamento do processo produtivo. Atualmente, na área de fabricação por usinagem, busca-se extrair dos equipamentos envolvidos no processo o máximo de produtividade. Associado a isto, está o surgimento de novos equipamentos, especialmente os que utilizam Comando Numérico Computadorizado (CNC) minimizando os tempos relativos a troca de ferramenta e possibilitando um melhor planejamento da produção. A introdução dos computadores na confecção do plano de processo torna o planejamento da produção mais eficiente, podendo dispor de mais alternativas no cronograma de produção, resultando no aumento da produtividade com o uso de planos otimizados. Este trabalho teve como objetivo dar uma contribuição ao planejamento da produção, mostrando como se pode identificar numa célula flexível de manufatura a melhor alocação e seqüenciamento de fabricação de um lote composto de diferentes tipos de peças. Os parâmetros de corte para o processo de fresamento frontal foram otimizados para a máxima produção. Com a ajuda da programação linear mostrou-se como se pode decidir a quantidade de peças que devem ser usinadas nas diferentes máquinas ferramentas componentes de uma Célula Flexível de Manufatura
3

Optimierung von Wirtschaftlichkeit und Humanität bei der rechnergestützten Planung von Gruppenarbeit /

Arendt, Michael. January 1997 (has links)
Zugl.: Braunschweig, Techn. Universiẗat, Diss., 1996.
4

Razvoj sistema za simultano projektovanje proizvoda i tehnoloških procesa / Development of an System for Simultaneously Product and Process Planning Design

Borojević Stevo 03 July 2015 (has links)
<p>U okviru istraživanja na predmetnoj disertaciji prikazana je analiza stanja i pravci razvoja u oblasti simultanog projektovanja proizvoda i tehnoloških procesa. Detaljnije su opisane tehnike CAD/CAPP integracije na bazi tehnoloških tipskih formi i vještačke inteligencije. Na bazi ovih analiza razvijen je model simultanog projektovanja proizvoda i tehnoloških procesa. Na osnovu modela sistema, razvijen je programski sistem za simultano projektovanje proizvoda i tehnoloških procesa. Prikazani su rezultati primjene razvijenog sistema na primjeru hidraulične prese za ugaono savijanje lima, kao proizvoda, i hidrauličnog cilindra, kao dijela proizvoda. Disertacija obuhvata i moguće pravce budućeg istraživanja.</p> / <p>The research in this dissertation encompassed state-of-the-art and future development in the field of simultaneously product and process planning design. Technics of CAD/CAPP integration based at manufacturing features and artificial intelligence are described in detail. Based on this analysis it was developed a model of simultaneously product and process planning design. Based on this model, program system for simultaneously product and process planning design was developed. Case studies were presented at the example of hydraulics press brake for sheet metal bending, as products, and hydraulics cylinder, as part of the product. In dissertation it was also suggested directions of future investigation in this field.</p>
5

A multidisciplinary and collaborative problem solving architecture for high-level computer aided process planning in discrete manufacturing

Botef, Ionel 22 February 2007 (has links)
Student Number : 0111474R - PhD thesis - School of Mechanical, Industrial and Aeronautical Engineering - Faculty of Engineering and the Built Environment / One of the most daunting challenges in Computer Integrated Manufacturing (CIM) is bridging the gap between Computer Aided Design (CAD) and Computer Aided Process Planning (CAPP). Past research into CAPP, considered one of the most important and most complicated computer aided systems, resulted in a wealth of knowledge but unresolved problems still exist. The actual CAPP systems are considered large, complex, and monolithic, with limited extensibility, low-level of integration with other applications, and high development and maintenance costs. Consequently, this thesis develops a new framework that focuses on a CAPP architecture for problem solving that manages complexity through simplicity, and applies principles and strategies used in manufacturing enterprise management, automation, robotics, and software engineering, that finally leads to a system of systems which is human-centric, architectural-centric, process-centric, and in line with the IT (Information Technology) infrastructure trends. Thereafter, the framework is used to develop a number of software applications that apply object-oriented programming as a new way of thinking about solving CAPP problems and as a promising alternative to other techniques. Then, the capabilities of the new approach are demonstrated through the use of examples. The thesis ends with conclusions about the new CAPP approach, and finally highlights its theoretical and practical implications.
6

Process capability modelling for manufacturing process selection in an integrated simultaneous engineering workstation

Naish, Jane Catherine January 1999 (has links)
No description available.
7

Interaktive Montageplanung mit Kollisionserkennung

Schömer, Elmar. Unknown Date (has links) (PDF)
Universiẗat, Diss., 1994--Saarbrücken.
8

Uma avaliação da aplicação de sistemas de planejamento de processos (CAPP) na indústria de manufatura brasileira / An applicability evaluation of computer aided process planning systems (CAPP) in the Brazilian manufacturing industry

Paranaguá, Leonardo Charles Malafaia 05 October 2001 (has links)
A importância deste trabalho encontra suas fundamentações na atual relevância de pesquisas sobre avaliação de impacto de sistemas de informação e na importância dos sistemas CAPP para a indústria de manufatura. A necessidade de avaliar sistemas de informação surgiu de um fenômeno conhecido como paradoxo da produtividade (falta de evidência de retornos para altíssimos investimentos). Já o CAPP é um sistema fundamental na interface de Engenharias e Produções, sendo gerador de informações para toda a empresa. Para a obtenção este objetivo foram realizadas análises de dados colhidos em 11 casos investigados. / The importance of this work meets its foundation both in the nowadays relevance of studies on information systems impact and in the importance of CAPP systems to the manufacturing industry. The necessity of evaluating information systems emerged from a situation known as the productivity paradox (lack of return evidence in despite high investments). Regarding the CAPP, it is a fundamental system to do the interface between the Project and the Production areas, being also a generator of important information to the whole company. To reach these goals, some analysis were carried on data collected from 11 case studies.
9

Uma avaliação da aplicação de sistemas de planejamento de processos (CAPP) na indústria de manufatura brasileira / An applicability evaluation of computer aided process planning systems (CAPP) in the Brazilian manufacturing industry

Leonardo Charles Malafaia Paranaguá 05 October 2001 (has links)
A importância deste trabalho encontra suas fundamentações na atual relevância de pesquisas sobre avaliação de impacto de sistemas de informação e na importância dos sistemas CAPP para a indústria de manufatura. A necessidade de avaliar sistemas de informação surgiu de um fenômeno conhecido como paradoxo da produtividade (falta de evidência de retornos para altíssimos investimentos). Já o CAPP é um sistema fundamental na interface de Engenharias e Produções, sendo gerador de informações para toda a empresa. Para a obtenção este objetivo foram realizadas análises de dados colhidos em 11 casos investigados. / The importance of this work meets its foundation both in the nowadays relevance of studies on information systems impact and in the importance of CAPP systems to the manufacturing industry. The necessity of evaluating information systems emerged from a situation known as the productivity paradox (lack of return evidence in despite high investments). Regarding the CAPP, it is a fundamental system to do the interface between the Project and the Production areas, being also a generator of important information to the whole company. To reach these goals, some analysis were carried on data collected from 11 case studies.
10

Τα λιποσώματα ως μοντέλα για την μελέτη της επίδρασης ψυχρού πλάσματος ατμοσφαιρικής πίεσης σε κύτταρα

Ματραλή, Σοφία - Στυλιανή 12 June 2015 (has links)
Τα λιποσώματα αναπτύχθηκαν αρχικά από τον Alec Bangham το 1964. Έκτοτε μελετώνται τόσο ως φορείς βιοδραστικών ενώσεων όσο και ως μοντέλα βιολογικών μεμβρανών με σκοπό την αποσαφήνιση της δομής και των λειτουργιών τους. Αυτό οφείλεται στο γεγονός ότι αποτελούνται από τα ίδια δομικά συστατικά με εκείνα των βιολογικών μεμβρανών και η ευελιξία της δομής τους προσφέρει τη δυνατότητα προσομοίωσης της δομής και σύστασης διαφορετικών βιολογικών μεμβρανών. Στις εφαρμογές του ψυχρού πλάσματος ατμοσφαιρικής πίεσης, cold atmospheric pressure plasma (CAPP), που μελετώνται τα τελευταία χρόνια συγκαταλέγονται και βιοιατρικές εφαρμογές. Συγκεκριμένα μελετάται η χρήση του ως μέσω απολύμανσης και αποστείρωσης, στην ανάπλαση δέρματος, ως αντικαρκινική θεραπεία κ.τ.λ. Εντούτοις ο ακριβής μηχανισμός της αλληλεπίδρασης του ψυχρού πλάσματος ατμοσφαιρικής πίεσης με κύτταρα και ιστούς δεν είναι ακόμα πλήρως κατανοητός. Παρότι οι μέχρι τώρα μελέτες για την αποσαφήνιση της αλληλεπίδρασης αυτής πραγματοποιούνται με την χρήση κυτταρικών καλλιεργειών, η χρήση λιποσωμάτων είναι μια πιθανή εναλλακτική. Αυτό οφείλεται στο γεγονός ότι η χρήση λιποσωμικών διασπορών, ως μοντέλα κυττάρων, έχει αποδειχθεί μια πιο εύκολη, ταχύτερη και χαμηλότερου κόστους εναλλακτική των κυτταρικών καλλιεργειών για την αποσαφήνιση βιολογικών διεργασιών. Η παρούσα εργασία έχει ως σκοπό τη διερεύνηση της δυνατότητας χρήσης των λιποσωμάτων ως μοντέλα βιολογικών μεμβρανών για την μελέτη της αλληλεπίδρασης του CAPP με κύτταρα. Μελετήθηκε η αλληλεπίδραση λιποσωμάτων – CAPP και επιχειρήθηκε η παραμετροποίηση της αλληλεπίδρασης αυτής. Τα λιποσώματα, που εγκλωβίζουν υδατικό διάλυμα καλσεΐνης, παρασκευάσθηκαν με την τεχνική της ενυδάτωσης λεπτού υμενίου και έγινε χρήση υπερήχησης με σκοπό την μείωση του μεγέθους τους. Τα λιπίδια που χρησιμοποιήθηκαν ήταν: φωσφατιδυλοχολίνη, φωσφατιδυλογλυκερόλη και χοληστερόλη. Υπέστησαν επεξεργασία τόσο με CAPP όσο και με αφόρτιστο φέρον αέριο. Ο χαρακτηρισμός των λιποσωμάτων έγινε μέσω μέτρησης των φυσικοχημικών τους χαρακτηριστικών. Ως μέτρο της αλληλεπίδρασης CAPP-λιποσωμάτων χρησιμοποιήθηκε η μεταβολή του εγκλωβισμού της καλσεΐνης. Επιπλέον πραγματοποιήθηκε μορφολογική ανάλυση των λιποσωμάτων, μέσω ηλεκτρονιακής μικροσκοπίας σάρωσης, πριν και μετά την επεξεργασία. Με σκοπό την παραμετροποίηση της αλληλεπίδρασης αυτής έγινε μελέτη της μεταβολής των φυσικοχημικών ιδιοτήτων των λιποσωμάτων ως συνάρτηση του χρονικού διαστήματος επεξεργασίας και του χρόνου επώασης (σε PBS στους 4C) μετά την επεξεργασία. Επιπλέον πραγματοποιήθηκαν πειράματα αλληλεπίδρασης του CAPP με κύτταρα B-16, καρκινικά κύτταρα μελανώματος ποντικού. Ως οι κυριότεροι παράγοντες της αλληλεπίδρασης CAPP – λιποσωμάτων διαφαίνονται η συγκέντρωση της λιποσωμικής διασποράς και ο χρόνος επεξεργασίας. Η μείωση του ποσοστού εγκλωβισμού της καλσεΐνης αυξάνεται ανάλογα με την αύξηση τόσο της συγκέντρωσης όσο και του χρόνου επεξεργασίας. Επιπλέον η λιπιδική σύσταση επηρεάζει το αποτέλεσμα της αλληλεπίδρασης. Η ύπαρξη αρνητικού επιφανειακού φορτίου επηρεάζει θετικά το αποτέλεσμα της αλληλεπίδρασης ενώ η ύπαρξη χοληστερόλης οδηγεί σε πιο ανθεκτικά λιποσώματα μόνο στη μέγιστη συγκέντρωση (50%). Μείωση του μεγέθους και του αριθμού των διπλοστιβάδων των λιποσωμάτων οδηγεί σε πιο ευαίσθητα κυστίδια. Διαφυγή της καλσεΐνης παρατηρήθηκε μέχρι και 96 ώρες μετά την επεξεργασία ενώ με το πέρας του χρόνου παρατηρήθηκε επιπλέον συσσωμάτωση των κυστιδίων, το οποίο επιβεβαιώνεται με μορφολογικές μελέτες, και μεταβολή τους επιφανειακού τους φορτίου. Η επίδραση του CAPP στα κύτταρα Β-16 επηρεάζεται τόσο από την αρχική πληρότητα (confluence) της καλλιέργειας όσο και από τις διαστάσεις των κελιών της χρησιμοποιούμενης πλάκας. Παρότι η ανωτέρω ανάλυση υποστηρίζει την αρχική υπόθεση, απαιτείται περαιτέρω διερεύνηση της αλληλεπίδρασης του CAPP με βιολογικά δείγματα. / Liposomes were originally developed by Alec Bangham in 1964. Since then, they have been studied as carriers of bioactive compounds and as biological membrane models in structural and functional studies. This is due to the fact that they are composed of the same building blocks as biological membranes and because their structural versatility offers the opportunity to create vesicles that resemble the structure and composition of different biological membranes. In recent years cold atmospheric pressure plasma, CAPP, has been studied for a variety of applications some of which are found in the biomedical milieu. More precisely these applications include: decontamination, sterilization, skin regeneration, tumor treatment, etc. Nevertheless the exact mechanism of the interaction between CAPP and cells/tissue is not yet completely understood. Although currently researchers use cell cultures to investigate this interaction, liposomes could be an alternative. The applicability of liposomal dispersions, as cell models, has proved to be an easier, faster and less expensive tool for the investigation of cell – cellular environment interactions. The purpose of this thesis was to investigate the possibility of using liposomes as cell membrane models to study the CAPP-cells interactions. The CAPP-liposomes interaction was studied and parameterization of this interaction was attempted. Calcein-encapsulating liposomes were prepared using the thin-film hydration technique and the sonication technique was used to decrease the size of the vesicles. The lipids used were: phosphatidylcholine, phosphatidylglycerol and cholesterol. The samples were treated both with CAPP and with the uncharged carrier-gas. Characterization of liposomes was made by measuring their physicochemical characteristics. The variation of the percent of calcein encapsulation was used to measure the effect of CAPP-liposomes interaction. Moreover morphological evaluation of the samples before and after treatment was realized thought scanning electron microscopy, SEM. The variation of liposomes’ physicochemical characteristics versus time, duration of treatment and incubation (in PBS at 4C), was realized in order to parameterize this interaction. The effect of CAPP on B-16 cells, mouse melanoma cancer cells, was also investigated. The major parameters of the CAPP-liposomes interaction were proved to be the concentration of the liposomal dispersion and the duration of treatment. The increase of both the lipid concentration and the duration of treatment lead to increase of the reduction of calcein’s encapsulation provoked by CAPP treatment. The composition of the liposomal membrane also affects the interaction’s result. Negative surface charge increases the impact of CAPP and the presence of cholesterol leads to more stable structures only when its concentration is maximum (50%). Reduction of the size and lamellarity of the vesicles leads to more fragile liposomes. Release of calcein was observed even 96 hours after treatment in combination with aggregation of the vesicles, which was also proved via morphological evaluation, and change of liposomes’ surface charge. The impact of CAPP treatment on B-16 cells seems to depend on the initial confluence of the culture as well as the dimensions of the plate’s wells. Although the aforementioned analysis supports the initial hypothesis, further investigation of the interaction between CAPP and biological samples is necessary.

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