The purpose of this study is to evaluate the performance of the 5/16 in. diameter Elco Grade 8 standoff screw as a mechanical shear connector in composite joists. Standoff screws are being investigated as an alternative to welded shear studs in short span composite joists. The data and results obtained from 106 pushout tests performed on the Elco Grade 8 standoff screw are presented. The test parameters include: standoff screw height, quantity of standoff screws per deck rib, standoff screw position, slab depth, base angle thickness, deck type, and amount of transverse reinforcement. The test results from this study are compared to those obtained in previous research performed by Hankins (1994), and the applicability of Hankins' predictive equation for the shear strength of the Elco Grade 8 standoff screw is investigated. The influences of various test parameters on the shear strength of the standoff screw are evaluated and the effects of grouping the standoff screws in the deck ribs are examined. The performance of the standoff screw in solid slab applications is also investigated. Predictive equations for the shear strength of the Elco Grade 8 standoff screw, based on screw-related failure modes, concrete rib failures, and longitudinal splitting of solid concrete slabs, are presented. / Master of Science

The purpose of this study is to further evaluate the performance of the 5/16 in. diameter Elco Grade 8 standoff screw as a mechanical shear connector in composite joists. Standoff screws are being investigated as viable an alternative to welded shear studs in short span composite joists. The data and results obtained from 59 pushout tests performed on the 5/16 in. diameter Elco Grade 8 standoff screw are presented. The test parameters investigated in this study include: standoff screw height, quantity of standoff screws per deck rib, standoff screw position, slab depth, base angle thickness, deck type, and amount of transverse reinforcement. Test results gathered in this study are used in conjunction with selected test data from research performed by Alander (1998). This combined test data is used in determining the validity of existing predictive equations for the shear strength of the 5/16 in. diameter Elco Grade 8 standoff screw. The influence of various independent variables on shear strength is investigated for all screw densities tested. The performance of the 5/16 in. diameter Elco Grade 8 standoff screw in solid slab applications is also investigated. Proposed predictive equations for the shear strength of the 5/16 in. diameter Elco Grade 8 standoff screw based on screw-related failure modes, concrete cone failures and longitudinal splitting, are presented. / Master of Science

Abstract Taiwan has won the good name of ¡§the Kingdom of Fasteners¡¨ for years. With the dedication by the whole industry the exporting volume of fasteners products kept significantly growing every year in Taiwan and the production scale has become the leading position worldwide as well. However, due to the unlimited investment along with large expansion of production capacity made in the past decade, the market situation tends to be oversupplied. Price war emerges whenever business gets slow, as a result, the exporting price keeps dropping year by year and Taiwan is likely to be the target of foreign anti-dumping suits. As a matter of fact, Taiwan fastener industry has encountered several anti-dumping suits before. Among all the cases, the European anti-dumping suit on import of stainless steel fasteners has resulted in a considerable impact to the industry that the exporting volume of fasteners products has significantly decreased since 1988 and many companies were forced to seek for other markets, downscale their operation or even move the factories to overseas. The Agreement on Implementation of Article VI of the General Agreement on Tariffs and Trade 1994 exercises multilateral agreement to sanction the dumping activities based on non-discrimination principle and adopts necessary measure to restrict the dumping activities. As a result, to avoid any negative impact caused by the free trade and protect the benefit of local industries, every country is allowed to bring the anti-dumping law into their trading policy. However, we noted from the evolution of the trading policy that the mechanism of protection measure has been shift from tariff barrier to be non-tariff barrier, and from non-tariff barrier to the abuse or misuse of WTO regulation, the discretion of the administration has even become one of the mechanisms. This paper is intended to emphasize the impact to the free trade by anti-dumping measure and the impropriety of the European anti-dumping system. This paper includes six chapters: Chapter 1 - General introduction; Chapter 2 ¡V The development of Taiwan fasteners industry; Chapter 3 ¡V The illustration of the European anti-dumping system and suit case; Chapter 4 ¡V The initial and definitive determinations of suit case; Chapter 5 ¡V The disputes of legal procedure and substance; Chapter 6 ¡V Conclusion and suggestion.

Thesis (M.B.A.)--University of Hong Kong, 1980.

Orientador: Luis Augusto Passeri / Tese doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-09T20:14:50Z (GMT). No. of bitstreams: 1 Brasileiro_BernardoFerreira_D.pdf: 9990302 bytes, checksum: ddce5ea3896243c2b52242b595e7946d (MD5) Previous issue date: 2007 / Resumo: Um melhor entendimento biomecânico da fixação interna rígida (FIR) na osteotomia sagital dos ramos mandibulares (OSRM) pode ser baseado em pesquisas com o intuito de investigar sua função in vitro antes da aplicação clínica. Assim, este trabalho teve como objetivo avaliar comparativamente a resistência de três diferentes técnicas de FIR em réplicas de hemimandíbulas humanas de poliuretano simulando a OSRM para movimentos de 5 mm em avanço e recuo. As técnicas de FIR incluíram uma miniplaca ponte com 4 furos e 4 parafusos monocorticais (grupo miniplaca), uma miniplaca com 4 furos e 4 parafusos monocorticais mais um parafuso bicortical posicional (grupo híbrido) e 3 parafusos bicortical posicionais em configuração em ¿L¿ invertido (grupo ¿L¿ invertido). Os parafusos e as miniplacas utilizados eram de titânio e pertencentes ao sistema de 2,0 mm. Estes foram avaliados quanto à padronização dimensional por meio do coeficiente de variação, que evidenciou alta semelhança macroscópica. As hemimandíbulas foram submetidas a testes de carregamento linear vertical e lateral por uma unidade de testes mecânicos Instron 4411 para registro da carga de pico aos deslocamentos de 1 mm, 3 mm, 5 mm e 10 mm. Médias e desvio padrão foram avaliados aplicando-se a Análise de Variância e o teste de Tukey em nível de significância de 5%. O grupo miniplaca apresentou menores valores de carga de pico ao deslocamento (p<0,01) quando comparada com as outras técnicas de fixação considerando-se igual tipo de movimento e direção de carga. O grupo ¿L¿ invertido foi ainda superior em resistência (p<0,01) ao grupo híbrido em movimento de avanço e com aplicação de carga verticalmente. Concluiu-se que a utilização da técnica de FIR para a OSRM baseada em 3 parafusos bicorticais em ¿L¿ invertido foi a mais estável, e que a colocação de um parafuso bicortical pode otimizar significativamente a resistência da fixação com miniplacas e parafusos monocorticais / Abstract: A better understanding of the biomechanics of sagittal split ramus osteotomy (SSRO) rigid internal fixation (RIF) can be based on research aiming to evaluate its function in vitro before clinical application. Thus, the goal of this investigation was to evaluate comparatively the resistance of three different RIF techniques applied to polyurethane synthetic hemi-mandible replicas simulating the SSRO for 5 mm advancement and setback. RIF techniques included a 4-hole miniplate and 4 monocortical screws (miniplate group), a 4-hole plate and 4 monocortical screws with one additional bicortical positional screw (hybrid group), and 3 bicortical positional screws in a traditional inverted-L pattern (inverted-L group). Screws and miniplates were made of titanium and from 2.0 mm system. These were analyzed according to dimensional standardization by a coefficient of variation, which revealed high macroscopic similarity. The hemi-mandibles were submitted lateral and vertical loading tests in an Instron 4411 mechanical testing unit for recording of peak loading at 1 mm, 3 mm, 5 mm and 10 mm of displacement. Means and standard deviation were analyzed using Analysis of Variance and Tukey test with a 5% level of significance. Miniplate group showed lower load peak scores (p<.01) when compared to the others fixation techniques regarding equal type of movement and force direction. Inverted-L group demonstrated higher resistance (p<.01) than hybrid group during advancement and with application of vertical load. It was concluded the RIF technique for SSRO based on 3 bicortical screws in the inverted-L pattern was the most stable, and the installation of a bicortical screw may significantly optimize the resistance of the miniplate and monocortical screws fixation / Doutorado / Cirurgia e Traumatologia Buco-Maxilo-Faciais / Doutor em Clínica Odontológica

Orientadores: Valfrido Antonio Pereira Filho, Luis Augusto Passeri / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T11:01:55Z (GMT). No. of bitstreams: 1 Iamashita_HericYukio_M.pdf: 10483371 bytes, checksum: 43fabb9ac62869422ae0c9f7b447d409 (MD5) Previous issue date: 2009 / Resumo: Estudos têm proposto diversas técnicas e métodos de fixação interna rígida (FIR) no sentido de se obter maior estabilidade dos segmentos ósseos e mínimo deslocamento condilar após osteotomia sagital do ramo mandibular (OSRM). Desta forma, o presente estudo teve por objetivo avaliar por meio de ensaio mecânico de compressão em hemimandíbulas sintéticas, três diferentes tipos de fixações utilizadas na OSRM em movimento de avanço de 5 mm. Foram utilizadas 30 hemimandíbulas, divididas em 3 grupos com 10 hemimandíbulas em cada. O grupo 1 foi fixado com três parafusos posicionais de 15 mm do sistema 2,0 mm dispostos bicorticalmente na posição de L invertido e com angulação de inserção de 90°; no Grupo 2 a fixação foi realizada com placa de 4 furos do sistema 2,0 mm e 4 parafusos monocorticais de 6 mm de comprimento disposto sobre a região do canal mandibular, e o Grupo 3 a fixação consistiu de uma placa sagital ajustável do sistema 2,0 mm e 8 parafusos de 6,0 mm de comprimento também localizada sobre o canal mandibular. Sendo avaliados quanto à padronização, o sistema de fixação demonstrou semelhança dimensional. As hemimandíbulas foram submetidas a cargas compressivas verticais, por meio de ponta de aplicação de carga em máquina de ensaio universal MTS®, na velocidade de 1 mm/min com deslocamento máximo de 10 mm. Médias e desvios padrão foram obtidos e submetidos à análise de variância a um fator e teste HSD de Tukey com nível de significância de 5%. O Grupo 1 apresentou maiores valores de resistência à força de carga compressiva (p<0,001) sendo superior aos demais grupos. O Grupo 3 demonstrou a menor resistência às forças (p<0,001). Concluiuse que o uso de parafusos bicorticais posicionais em L invertido promove a maior capacidade de resistência às cargas compressivas, sendo que as placas sagitais ajustáveis apresentam-se cerca de 60% menos resistentes do que o Grupo 1. / Abstract: Studies have considered many techniques and methods of rigid internal fixation (RIF) leads to obtain greater stability to the bone segments and minimum displacement of the condyles after performed the sagittal split ramus osteotomy (SSRO). In this way, the purpose of this study was to evaluate by means of mechanical compression testing model with synthetic hemimandibles, three different fixation types used in the SSRO in movement of advance of 5 mm. Thirty hemimandibles, divided in 3 groups with 10 hemimandibles in each group. Group 1 was fixed with three 15 mm positional screws (2.0 mm diameter) bicortically in an inverted-L pattern and with insertion angle of 90°; in Group 2 the fixation was carried through with four-hole straight plate and four 6 mm monocortical screws made located on the region of the mandibular canal, and Group 3 the fixation is consisted of an adjustable sagittal plate and eight 6 mm screws also placed on the mandibular canal. Evaluated for dimensional standardization, the fixation system had demonstrated dimensional similarity. Hemimandibles had been exposed to the vertical compressive loads, by means of tip of load application in a MTS® mechanical testing unit, in the speed of 1 mm/min with maximum displacement of 10 mm. Averages and standard deviations had been obtained and submitted to the analysis of variance to a factor and have tested for HSD of Tukey test with a 5% level of significance. Group 1 presented greaters values of resistance to the compressive loads (p< 0.001) showed superior to the other groups. Group 3 demonstrated the lesser resistance to the loading forces (p< 0.001). It was concluded that the use of positional bicortical screws in inverted-L pattern promotes the higher capacities of resistance to compressive loads, moreover, the adjustable sagittal plates are presented about less resistant 60% that the Group 1. / Mestrado / Cirurgia e Traumatologia Buco-Maxilo-Faciais / Mestre em Clínica Odontológica

Orientadores: Alexandre Elias Trivellato, Marcio de Moraes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-21T07:03:24Z (GMT). No. of bitstreams: 1 Cavalieri-Pereira_Lucas_D.pdf: 1578055 bytes, checksum: 8c7fc995f3dac6a8d0d45c1bc49f3175 (MD5) Previous issue date: 2012 / Resumo: Fraturas do ângulo mandibular são muito freqüentes dentre as fraturas mandibulares e um das formas de tratamento é a utilização de fixação interna com placas e parafusos. Neste estudo o objetivo foi avaliar comparativamente a resistência de três tipos de fixação em réplicas de mandíbula de poliuretano, empregando-se a técnica de Champy. Foram utilizadas 63 mandíbulas dentadas, submetidas aa seccionamento simulando uma fratura linear e favorável de ângulo mandibular esquerdo. As fixações foram realizadas com placas retas do sistema 2,0 mm, dispostas da seguinte forma: uma placa com quatro furos, uma com cinco furos e uma com quatro furos e extensão (ponte). A estabilização e fixação foram realizadas com adaptação da placa e quatro parafusos de 6,0 mm de comprimento, sobre a linha oblíqua da mandíbula. Foram elaborados 9 grupos, com 7 mandíbulas cada um, sendo 3 grupos fixados com placa de 5 furos, 3 com placa reta de 4 furos com extensão e 3 com placa reta de 4 furos. Cada conjunto foi submetido ao teste de carregamento linear com aplicação de carga no sentido súpero-inferior em três pontos distintos da mandíbula, de modo não simultâneo (região de molar ipsilateral à secção, incisivos centrais e molar contralateral) em máquina de ensaio universal EMIC DL 2000. Foram mensurados valores de carga no deslocamento de 1 mm, 2 mm e final e anotado o deslocamento final. Os resultados obtidos foram submetidos à análise estatística, utilizando a análise de variância (ANOVA), seguido do teste de Tukey, nível de significância de 5%. Nos valores de cargas obtidos, tanto quando aplicada no molar ipsilateral ao seccionamento, no molar contralateral ao seccionamento e entre incisivos centrais, foi verificada diferença estatística somente no momento do deslocamento final, na qual a placa com 5 furos e com 4 com extensão foi superior a placa com quatro furos. Não houve diferença entre placa com 5 furos e com 4 com extensão / Abstract: Mandibular angle fractures are very frequent among the mandibular fractures and a form of treatment is the use of internal fixation with plates and screws. In this study, the objective was to evaluate the resistance of three types of fixation in mandibular replicas of polyurethane, using the technique of Champy. Sixty three toothed mandibles were used, subject to sectioning simulating a linear and favorable fracture of left mandibular angle. The fixations were performed with straight plates system 2.0 mm, prepared as follows: one plate with 4-holes, one with 5-holes and one 4-holes and extension (bridge). Stabilization and adjustment were performed with locking plate and four screws of 6.0 mm in length, about the oblique line of the mandible. Nine groups were elaborated, with 7 each, which 3 groups being fixed with 5-holes plates, 3 groups with 4-holes plates with extension and 3 groups with 4-holes plates. Each set was submitted for loading test with load application towards in three distinct points of the mandible, so do not simultaneously (molar region on the side ipsilateral of section, the central incisors and contralateral molar) in universal testing machine EMIC DL 2000. Load values were measured at offset 1 mm, 2 mm and final and was noted the final dislocation. The results were submitted to statistical analysis, using analysis of variance (ANOVA) followed by Tukey test, a significance level of 5%. The values obtained, when loads were applied in the ipsilateral molar, contralateral molar and incisors, was verified statistically only at the final dislocation, in which the 5-holes plates and 4-holes with extension was more resistant than 4-holes plates. There was no difference between plate with 5-holes and 4-holes with extension / Doutorado / Cirurgia e Traumatologia Buco-Maxilo-Faciais / Doutor em Clínica Odontológica

In the field of orthopaedics and traumatology, a whole series of problems appear related to fracture fixation by means of various types of plates. Appropriate application of the plate is the difficult task that a doctor needs to deal with in the operating room. Regarding mechanics, the number of screws and their spacing have a major impact on the healing process. If there are too many screws or lack of them, the fracture does not heal properly. This can lead to implant failure. This work deals with stress-strain analysis of screws and bone tissue with a fracture fixed by LCP. It deals with the influence of different geometrical configurations of the screws on the stress, deformation and strain of the system. For this purpose, the computational modelling was used by means of the finite element method. Two computational models have been created, on which different screw arrangement was analysed. The first computational model represents diaphysis of the femur that is at the beginning of the healing process. For the four load models and eleven geometric configurations and number of the screws, a total of 44 computations were performed. The second computational model represents the distal part of the femur. Femoral geometry model was created based on CT (computed tomography) examination, geometric model of the plate was created by 3D scanning. Deformations and stresses were compared in the three geometric configurations of the screws during the healing process.

Today, distinct approaches are required when designing timber structures and their joints in the event of fire. Considering that the steel fasteners have temperature dependent properties and that the surrounding wooden construction is also affected by the fire due to occurrence of charring during fire exposure, these types of joints are complicated to design.  This study includes an overview of existing knowledge in the subject, where a literature survey has been conducted to enlighten current design procedures, previous research, and available test methods for axially loaded screw joints in wooden structures exposed to fire. The literature survey has been supplemented with an interview survey, in which six respondents’ knowledge in the subject and desires for future studies have played the main role.  The results from this study clearly indicates that the existing knowledge regarding axially loaded screw joints in wooden structures exposed to fire is insufficient. Today’s standards for the design of these types of joints are incomplete with respect to the referred joint arrangement and there are no explicit test methods for determination of the strength of these joints under fire exposure. A few previous studies have been carried out and the results from these have proven to be difficult to interpret since the experimental set-up was not consistent between the fire tests. This complicates the process of determining which factor has the greatest impact on the strength of the joint and the main underlying causes generating a collapse of the structure. The interview survey further strengthens the perception, based on the literature survey, that there is a lack of knowledge in the subject.  By mapping the existing knowledge in the subject it has been possible to identify deficiencies in current information and, finally, creating and proposing a test method for future tests of axially loaded screw joints in wooden structures exposed to fire. The proposed test method is influenced by existing test methods and design conditions for structures at normal temperatures. The development of this test method has its primary purpose in the ambition that the knowledge of axially loaded screw joints in fire exposed wooden structures can be expanded.

No description available.