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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

Método de ensaio de ligações de estruturas de madeira por chapas com dentes estampados / Test method for joints of timber structures made with metal plate connector

Baraldi, Lívio Túlio 11 October 1996 (has links)
Este trabalho apresenta uma proposta de método de ensaio para determinação da resistência de ligações em peças estruturais de madeira por chapas com dentes estampados e também verifica os modos de ruptura destas ligações. Para esta finalidade foram realizados ensaios com 5 (cinco) espécies de madeira classificadas de acordo com as classes de resistência apresentadas no projeto da nova norma brasileira para estruturas de madeira, a PNBR 7190/1996 - Projeto de Estruturas de Madeira. No trabalho são verificados 3 (três) modos básicos de ruptura das ligações, a saber: tração da chapa, cisalhamento da chapa e arrancamento dos dentes da chapa da peça de madeira. Dentro de cada modo de ruptura verifica-se os efeitos da variação da posição da chapa em relação à direção de aplicação da força. Determina-se também a resistência da ligação de acordo com o proposto pelo projeto da nova norma brasileira para estruturas de madeira (PNBR 7190, 1996). / The aim of this work is to propose a test method to determine the strength and to verify failure modes of timber joints made with metal connectors plate. To this purpose, several tests were made with 5 species of wood, which were classified according to the strength class introduced in the new Brazilian Standard for Timber Structures, NBR 7190/1996 - Timber Structure Project. In this work are verified 3 failure modes: metal connector plates under shear force and pure tension force, and lateral resistance strength of metal connector plate teeth. For each failure mode is verified the effect of the position of the plate under the direction of force. The resistance of joints are determine in agreement to the new Brazilian Standard for Timber Structures.
2

Método de ensaio de ligações de estruturas de madeira por chapas com dentes estampados / Test method for joints of timber structures made with metal plate connector

Lívio Túlio Baraldi 11 October 1996 (has links)
Este trabalho apresenta uma proposta de método de ensaio para determinação da resistência de ligações em peças estruturais de madeira por chapas com dentes estampados e também verifica os modos de ruptura destas ligações. Para esta finalidade foram realizados ensaios com 5 (cinco) espécies de madeira classificadas de acordo com as classes de resistência apresentadas no projeto da nova norma brasileira para estruturas de madeira, a PNBR 7190/1996 - Projeto de Estruturas de Madeira. No trabalho são verificados 3 (três) modos básicos de ruptura das ligações, a saber: tração da chapa, cisalhamento da chapa e arrancamento dos dentes da chapa da peça de madeira. Dentro de cada modo de ruptura verifica-se os efeitos da variação da posição da chapa em relação à direção de aplicação da força. Determina-se também a resistência da ligação de acordo com o proposto pelo projeto da nova norma brasileira para estruturas de madeira (PNBR 7190, 1996). / The aim of this work is to propose a test method to determine the strength and to verify failure modes of timber joints made with metal connectors plate. To this purpose, several tests were made with 5 species of wood, which were classified according to the strength class introduced in the new Brazilian Standard for Timber Structures, NBR 7190/1996 - Timber Structure Project. In this work are verified 3 failure modes: metal connector plates under shear force and pure tension force, and lateral resistance strength of metal connector plate teeth. For each failure mode is verified the effect of the position of the plate under the direction of force. The resistance of joints are determine in agreement to the new Brazilian Standard for Timber Structures.
3

Contribuição para a definição de critérios para o dimensionamento da ligação entre peças estruturais de madeira por chapas metálicas com dentes estampados / not available

Carvalho, Johnny Soares de 21 June 2002 (has links)
O crescimento da população urbana, bem como as diferenças sociais brasileiras, têm causado significativa degradação nas condições de vida e de moradia em nosso país. Tal fato vem referenciar a necessidade de se intensificar as pesquisas que tenham como objetivos a produção de alternativas tecnológicas para solucionar-se tais problemas. Não é ainda comum no Brasil o uso de chapas com dentes estampados para se fazer a conexão de peças estruturais de madeira, apesar dessas se apresentarem como uma ótima alternativa estrutural e econômica para tal. A norma brasileira, NBR 7190/97 - Projeto de Estruturas de Madeira, não apresenta um método com os critérios de dimensionamento para tais tipos de ligação. Baseado em estudos teóricos e experimentais desenvolvidos no Laboratório de Madeira e Estruturas de Madeira (LaMEM), do Departamento de Engenharia de Estruturas da Escola de Engenharia de São Carlos, Universidade de São Paulo, são apresentados neste trabalho contribuições para o desenvolvimento de tais critérios para o dimensionamento destas ligações. O presente estudo foi desenvolvido para atender as especificações de espécies tropicais nativas e de reflorestamento encontradas em território nacional. / The increase number of urban population such as the social disparity of Brazilian people has caused significant degradation in habitation life style, increased slum numbers and the number of homeless people. Such fact strengthen the necessity of intensify researches that produce technological alternatives to solve this problems. In Brazil, it is not common see metal plate connectors in roof trusses, in spite of this connectors been a good structural and economical alternative to execute this joints. In Brazilian code, NBR 7190/97 - Timber Structures Design, design criteria for this kind of joints are not yet established. Based on theoretical and experimental studies, carried out in Wood and Timber Structures Laboratory, Structural Engineering Department, São Carlos Engineering School, São Paulo University, in this paper such criteria design will be presented. The study was developed and calibrated to attend the specifications of native specimens of Brazilian tropical wood species.
4

A Thin Flat Antenna Design for Third Generation Mobile Communication Systems

Chen, An-chia 06 June 2004 (has links)
By employing a low-cost loop antenna of simple structure, a novel antenna design to efficiently make use of the system ground plane of a PDA (personal digital assistant) is proposed. Owing to a small distance of 3 mm between the antenna and the ground plane, the propose antenna has a very low profile. By selecting a proper loop¡¦s length-to-width ratio, two resonant modes close to each other can be excited, which lead to an impedance bandwidth of 17%. In addition, because of the same direction of the surface currents on the radiating metal plate, the antenna peak gain reaches about 4.5 dBi, which is attractive for application in PDAs.
5

Parazitas / Parasite

Maziliauskaitė, Ivelija 03 July 2012 (has links)
Baigiamojo bakalauro darbo tema yra žmogaus, kaip parazito vystymasis. Siekiama išanalizuoti parazitizmo reiškinį žmonių tarpusavio bendravime, bei perteikti tai praktiniame darbe.Teorinėje dalyje analizuojamas parazitizmo reiškinys. Nagrinėjamos išnaudojimo, kenkėjiškumo, savanaudiškumo, manipuliavimo, svetimėjimo, žvėriškumo ir parazitizmo sąvokos, bei jų tarpusavio sąveika. Parazitizmo reiškinio ir jo atmainų užuominų ieškoma lietuvos bei užsienio menininkų darbuose. Nagrinėjama, kaip menininkai tai analizuoja ir vaizduoja. Remiantis surinkta medžiaga, praktiniame darbe toliau analizuojamas parazitizmo reiškinys. Pateikiami pradiniai darbo eskizai bei komentarai.Bakalauro darbą sudaro keturių iliustracijų ciklas, atliktas ant vieno lakšto kompozicinės aliuminio plokštės. Iliustracijos išraižytos su adata, į įrėžimus įtrinant dažus. Fonas dekoruotas naudojant aerozolinius dažus. Kompozicinei aliuminio plokštei suteikta netradicinė, analizuojamą temą papildanti, forma. / A Bachelor work theme is human, as parasite development. The aim is to analyze the phenomenon of parasitism in communication between people, and to convey it in the practical work.The theoretical part of work is an analysis of parasitism phenomenon. There are analysis of the conceptions of exploitation, selfishness, manipulation, alienation, cruelty, or parasitism, and their interaction. The phenomenon of parasitism and its variations sought clues in Lithuanian and foreign artist’s works. Looks how artists analyze it and show it in their works. On the basis of material collection, in the practical work there are analyzing the phenomenon of parasitism. In the theoretical part of work there are presenting initial sketches and comments of the practical work.Bachelor's thesis consists of four illustrations made on a single sheet of aluminum composite panel. Illustrations engraved with the needle and the scorings rubbed with the paints. The background is decorated with aerosol paints. To the composite aluminum plate provided the non-traditional form, with append the topic.
6

Contribuição para a definição de critérios para o dimensionamento da ligação entre peças estruturais de madeira por chapas metálicas com dentes estampados / not available

Johnny Soares de Carvalho 21 June 2002 (has links)
O crescimento da população urbana, bem como as diferenças sociais brasileiras, têm causado significativa degradação nas condições de vida e de moradia em nosso país. Tal fato vem referenciar a necessidade de se intensificar as pesquisas que tenham como objetivos a produção de alternativas tecnológicas para solucionar-se tais problemas. Não é ainda comum no Brasil o uso de chapas com dentes estampados para se fazer a conexão de peças estruturais de madeira, apesar dessas se apresentarem como uma ótima alternativa estrutural e econômica para tal. A norma brasileira, NBR 7190/97 - Projeto de Estruturas de Madeira, não apresenta um método com os critérios de dimensionamento para tais tipos de ligação. Baseado em estudos teóricos e experimentais desenvolvidos no Laboratório de Madeira e Estruturas de Madeira (LaMEM), do Departamento de Engenharia de Estruturas da Escola de Engenharia de São Carlos, Universidade de São Paulo, são apresentados neste trabalho contribuições para o desenvolvimento de tais critérios para o dimensionamento destas ligações. O presente estudo foi desenvolvido para atender as especificações de espécies tropicais nativas e de reflorestamento encontradas em território nacional. / The increase number of urban population such as the social disparity of Brazilian people has caused significant degradation in habitation life style, increased slum numbers and the number of homeless people. Such fact strengthen the necessity of intensify researches that produce technological alternatives to solve this problems. In Brazil, it is not common see metal plate connectors in roof trusses, in spite of this connectors been a good structural and economical alternative to execute this joints. In Brazilian code, NBR 7190/97 - Timber Structures Design, design criteria for this kind of joints are not yet established. Based on theoretical and experimental studies, carried out in Wood and Timber Structures Laboratory, Structural Engineering Department, São Carlos Engineering School, São Paulo University, in this paper such criteria design will be presented. The study was developed and calibrated to attend the specifications of native specimens of Brazilian tropical wood species.
7

Relationship between Tooth Withdrawal Strength and Specific Gravity for Metal Plate Truss Connections

Via, Brian Kipling 16 July 1998 (has links)
The objectives of this research were twofold: a) to define the relationship between tooth withdrawal and specific gravity for southern pine lumber and four different plate-to-wood load orientations, and b) to demonstrate how these relationships could be applied to new lumber grades to predict tooth withdrawal performance so that additional testing would not be necessary. The four orientations investigated were: a.) LRAA - plate axis parallel to load and wood grain parallel to load. b.) LREA - plate axis perpendicular to load and wood grain parallel to load. c.) LRAE - plate axis parallel to load and wood grain perpendicular to load. d.) LREE - plate axis perpendicular to load and wood grain perpendicular to load. For the LRAA, LREA, LRAE, LREE orientations, the following sample sizes were respectively: 27, 22, 27, and 29. Results showed specific gravity and embedment gap were excellent predictors of ultimate tooth withdrawal stress for the LRAA orientation. However, neither specific gravity nor percentage of latewood significantly influenced the location of tooth withdrawal. For the LREA orientation, specific gravity alone was a good predictor of ultimate tooth withdrawal stress. Furthermore, the side of the joint test specimen where tooth withdrawal initiated was dependent on the wood piece with the lowest mean specific gravity. For the LRAE orientation, specific gravity was a marginal predictor of ultimate tooth withdrawal stress. For the LREE orientation, specific gravity was a decent predictor of ultimate tooth-withdrawal stress. / Master of Science
8

Vliv plechů z amorfní oceli na prostupnost rušení transformátory / Influence of transformer lamination from amorphous steel on permeability disturbance by transformers

Konečný, Pavel January 2010 (has links)
Influence of transformer lamination from amorphous steel on permeability disturbance by transformer This diploma work is about difference between current materials and amorphous plates which are used as pivots of transformers. Samples are tested by frequence 50-2500 Hz. By using more suitable materials we avoid the unallowable electromagnetic interruption better and we get more positive continuance of the retroactivity on the net.
9

Performance Evaluation of Wet Metal Plate Electrostatic Precipitator

Bharmal, Huzefa A. January 2005 (has links)
No description available.
10

Analysis of Metal Plate Connected Wood Truss Assemblies under Out-of-Plane Loads

Mohamadzadeh, Milad 19 August 2014 (has links)
In 2012, falls from elevation in construction industry represented 36% of the total fatalities. The Occupational Safety and Health Administration requires workers to use fall protection systems where workers are 6 feet or more above a lower level. Anchors for fall protection systems attached to roof trusses may cause out-of-plane loading on these structures. Metal plate connected wood trusses (MPCWT) are not designed to carry out-of-plane loads and MPCWT performance under these loads are not evaluated in the design process. The goal of this research is to model and analyze MPCWT assemblies under out-of-plane loads. The rotational stiffness of truss-wall connections, and truss bracing elements are included in the structural component model. Previous experimental data of fall arrest anchor loading were used for model validation. A parametric study considering loading location, joint stiffness and dimension of trusses was conducted. The structural analog of the MPCWT assemblies were found to have first truss deflections within 4% difference, thereby the models were validated. From parametric study results, the load location was not changed the ultimate deflection in the truss assembly by maximum value of 9%. Out-of-plane joint stiffness was the parameter that caused a large difference in the deflection results, when the joists were assumed as either rigid or simple connections. The rotational stiffness of lateral and diagonal bracing should be included as model inputs for the accurate representation of experimental behavior. Truss lengths increased the deflection at the top chord of the first truss in the assembly as truss width increased. / Master of Science

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