Yes / In the design of phase shifters, the modeling equations are too complicated and require some approximations to be derived correctly by hand. In response to this problem, this paper presents a generalized concept, algorithm, and MATLAB code that provide the exact modeling equations of the transmission parameters and the scattering parameters of any 90^o wideband stub-loaded phase shifter. The proposed code gives the modeling equations in term of variables for any number of stubs and characteristic impedance value by utilizing the symbol-based analysis of the MATLAB. It also illustrates the results as a function of normalized frequency relative to the center frequency f_o, and can be and can be tailored to any user-defined frequency range. As a matter of comparison, a three-stub wideband 90^o stub-loaded phase shifter is simulated using CST Microwave Studio and experimentally fabricated on Rogers RT5880 dielectric substrate with dimensions of 30×40×0.8 〖mm〗^3. The comparison reveals the accuracy of the proposed computerized modeling with -10 dB impedance bandwidth equal to 90% (0.55 fo-1.45 fo), (90∓5 degrees ) phase difference bandwidth equal to 100% (0.5 fo-1.5 fo), and negligible insertion loss. The novelty of this work is that the proposed code provides the exact modeling equations of the stub-loaded phase shifter for any number of stubs regardless the complexity of the mathematical derivations.

The goal of this research was to study several methods of generating composite action using open-web joist-girders, designed and manufactured by Nucor Corporation. In addition to comparing the relative performance of these systems, it was intended to determine whether the current accepted design procedure for composite joists could be extended to joist-girders. / Master of Science

[pt] O uso de sistemas estruturais mistos no mercado brasileiro tem aumentado nos últimos anos. Nesses sistemas as seções de diversos elementos estruturais são compostas por aço e concreto e suas resistências à tração e à compressão, respectivamente, são utilizadas de forma otimizada. Este estudo tem por objetivo avaliar o comportamento estrutural do vigamento de piso misto tipo Stub-Girder, modificado para melhor aproveitamento dos perfis em sua fabricação. O estudo é baseado em formulações não lineares físicas por meio do método dos elementos finitos (MEF), com uso do software ANSYS. Para calibrar o modelo numérico, foram utilizados dados de ensaios em escala real disponíveis na literatura, além de um ensaio em escala real realizado no Laboratório de Estruturas do departamento de Engenharia Civil e Ambiental da PUC-Rio. Uma análise paramétrica foi realizada utilizando diversos tipos de perfis disponíveis no mercado brasileiro para que o sistema Stub-Girder modificado pudesse ser avaliado no que diz respeito à resistência e rigidez. Foi ainda mostrado que os modelos constitutivos adotados para o concreto apresentam resultados coerentes e próximos dos obtidos em laboratório. / [en] Steel-concrete composite structural systems are increasingly adopted in Brazil s construction industry. In these systems steel and concrete are used to create sections that behave in structurally efficient manner by utilizing steel s tensile strength and concrete s compressive strength. The purpose of this research is to evaluate the structural behavior of a Stub-Girder floor system, modified to improve the use of steel profiles in its manufacturing process. A numerical procedure is developed, based on nonlinear analysis through the use of the finite element method (FEM), employing the software ANSYS. To calibrate the numerical model, data from full-scale tests available in the literature were used in addition to a full-scale test carried out in the Structures Laboratory (Civil Engineering and Environment department, PUC-Rio). A parametric analysis was performed using several types of profiles available in the Brazilian market so that the modified stub-girder system could be evaluated regarding strength and stiffness. The constitutive models for concrete were shown to be coherent with laboratory results.

Thin-walled steel sections made from high strength thin cold-reduced G550 steel to Australian Standard AS 1397-1993 under compression are investigated experimentally and theoretically in this thesis. This thesis describes three series of compression tests performed on box-section stub columns, box-section long columns and lipped channel section columns cold-formed from high strength steel plates in 0.42 mm or 0.60 mm thickness with nominal yield stress of 550 MPa. The tests presented in this thesis formed part of an Australian Research Council research project entitled: Compression Stability of High Strength Steel Sections with Low Strain-Hardening. For the fix-ended stub column tests, a total of 94 lipped-square and hexagonal section stub columns were tested to study the influence of low strain hardening of G550 steel on the compressive section capacities of the column members. For the pin-ended long column tests, a total of 28 box-section columns were tested to study the stability of members with sections which undergo local instability at loads significantly less than the ultimate loads. For the fix-ended lipped channel section columns, a total of 21 stub and long columns were tested to study the failure resulting from local and distortional buckling with interaction between the modes. A numerical simulation on the three series of tests using the commercial finite element computer program ABAQUS is also presented as part of this thesis. The post-buckling behaviour of thin-walled compression members is investigated. The effect of changing variables, such as geometric imperfections and end boundary conditions is also investigated. The ABAQUS analysis gives accurate simulations of the tests and is in good agreement to the experimental results. Theoretical studies using finite strip methods are presented in this thesis to investigate the buckling behaviour of cold-formed members in compression. The theoretical studies provide valuable information on the local and distortional buckling stresses for use in the interaction buckling studies. The finite strip models used are the semi-analytical and spline models. As expected for the stub columns tests, the greatest effect of low strain hardening was for the stockier sections where material properties play an important role. For the more slender sections where elastic local buckling and post-local buckling are more important, the effect of low strain hardening does not appear to be as significant. The pin-ended and fix-ended long column tests show that interaction, which is between local and overall buckling in the box sections, and between local and distortional buckling in the open channel sections, has a significant effect on their member capacities. The results of the successful column tests and ABAQUS simulation have been compared with the design procedures in the Australian & New Zealand Standard for Cold-Formed Steel Structures AS&NZS 4600 and the North American Specification for Cold-Formed Steel Structural Members prepared by the American Iron and Steel Institute. The stub column tests show that the current design rules give too conservative predictions on the compressive section capacities of the column members; whereas the long column tests show that the current column design rules are unconservative if used in their current form for G550 steel. Three design proposals are presented in this thesis to account for the effects of high strength thin steels on the section and member capacities.

Thin-walled steel sections made from high strength thin cold-reduced G550 steel to Australian Standard AS 1397-1993 under compression are investigated experimentally and theoretically in this thesis. This thesis describes three series of compression tests performed on box-section stub columns, box-section long columns and lipped channel section columns cold-formed from high strength steel plates in 0.42 mm or 0.60 mm thickness with nominal yield stress of 550 MPa. The tests presented in this thesis formed part of an Australian Research Council research project entitled: Compression Stability of High Strength Steel Sections with Low Strain-Hardening. For the fix-ended stub column tests, a total of 94 lipped-square and hexagonal section stub columns were tested to study the influence of low strain hardening of G550 steel on the compressive section capacities of the column members. For the pin-ended long column tests, a total of 28 box-section columns were tested to study the stability of members with sections which undergo local instability at loads significantly less than the ultimate loads. For the fix-ended lipped channel section columns, a total of 21 stub and long columns were tested to study the failure resulting from local and distortional buckling with interaction between the modes. A numerical simulation on the three series of tests using the commercial finite element computer program ABAQUS is also presented as part of this thesis. The post-buckling behaviour of thin-walled compression members is investigated. The effect of changing variables, such as geometric imperfections and end boundary conditions is also investigated. The ABAQUS analysis gives accurate simulations of the tests and is in good agreement to the experimental results. Theoretical studies using finite strip methods are presented in this thesis to investigate the buckling behaviour of cold-formed members in compression. The theoretical studies provide valuable information on the local and distortional buckling stresses for use in the interaction buckling studies. The finite strip models used are the semi-analytical and spline models. As expected for the stub columns tests, the greatest effect of low strain hardening was for the stockier sections where material properties play an important role. For the more slender sections where elastic local buckling and post-local buckling are more important, the effect of low strain hardening does not appear to be as significant. The pin-ended and fix-ended long column tests show that interaction, which is between local and overall buckling in the box sections, and between local and distortional buckling in the open channel sections, has a significant effect on their member capacities. The results of the successful column tests and ABAQUS simulation have been compared with the design procedures in the Australian & New Zealand Standard for Cold-Formed Steel Structures AS&NZS 4600 and the North American Specification for Cold-Formed Steel Structural Members prepared by the American Iron and Steel Institute. The stub column tests show that the current design rules give too conservative predictions on the compressive section capacities of the column members; whereas the long column tests show that the current column design rules are unconservative if used in their current form for G550 steel. Three design proposals are presented in this thesis to account for the effects of high strength thin steels on the section and member capacities.

El objetivo general del presente trabajo de título fue ensayar perfiles soldados de sección T de forma aislada, los cuales forman parte de una conexión de momento, permitiendo unir la viga con la columna. Esto permitió estudiar algunos parámetros geométricos que influyen sobre su comportamiento y así poder determinar si el diseño teórico realizado es consecuente, además de plantear recomendaciones y buscar nuevas aristas de estudio. Se realizó una revisión del diseño del perfil soldado de sección T a través de la norma AISC 2005, para estimar las deformaciones y cargas máximas que se desarrollarían, para así escoger la máquina de ensayo a utilizar entre las disponibles, además de buscar en la literatura experiencias similares. El diseño original del perfil T, se realizó en un trabajo de título previo. A partir de las verificaciones realizadas, se determinó reducir en un 50 % las dimensiones geométricas del perfil respecto al original, con lo cual se pudo alcanzar los modos de falla en la máquina de tracción de que se disponía. Se ensayaron 11 configuraciones distintas, con dos especímenes por cada una de ellas, utilizando distintos espesores de ala y alma, además de variar la disposición de los pernos a tracción. Con la ayuda de piezas especiales, que reproducían la columna y viga, se procedió a cargar el perfil de forma monotónica en tracción hasta alcanzar un modo de falla. Los resultados empíricos difirieron de los teóricos en la magnitud de carga. El comportamiento global del perfil soldado de sección T, se encuentra dentro de lo esperado, acorde a experiencias de otros autores. Se determinó que el ala del perfil soldado de sección T, es el elemento que más contribuye a la deformación total y a la resistencia última de la conexión. La separación entre líneas de pernos a tracción respecto al alma, en conjunto con el espesor del ala, determinan la rigidez y resistencia global del conector. La soldadura es un elemento que bien diseñado y materializado, no afecta al comportamiento global. La razón recomendada entre espesores de ala y alma es de 1.75, para el rango de distancias entre líneas de pernos a tracción estudiados. Con los resultados obtenidos, se debe ajustar el modelo de elementos finitos de Desjouis, ya que existen diferencias. Se recomienda realizar nuevos ensayos a las configuraciones utilizadas, cargándolos en forma cíclica, para poder conocer su comportamiento ante este tipo de fuerzas, además de la utilización de pernos de tensión controlada, para asegurar una pretensión adecuada.

In this thesis, there are discussed use-cases of NoSQL database MongoDB implemented as a datastore for user data, which is stored by Datastore stubs in Google App Engine SDK. Existing stubs are not very well optimized for higher load; they significantly slow down application development and testing if there is a need to store larger data sets in these storages. The analysis is focused on features of MongoDB, Google App Engine NoSQL Datastore and interfaces for data manipulation in SDK - Datastore Service Stub API. As a result, there was designed and implemented new datastore stub, which is supposed to solve problems of existing stubs. New stub uses MongoDB as a database layer for storing testing data and it is fully integrated into Google App Engine SDK.

The evolving of the networking application and electronic components are pushing the bandwidth limits in the automotive domain [19]. Consequently, the car manufacturers have begun to produce more complex Electronic Control Units (ECUs) to fulfil the automotive technology evolution. Car manufacturers have used ECUs from different vendors to get the most creative features in cars [19]. These ECUs requires a standard network interface such as Ethernet which can bring significant features such as high bandwidth, low weight and full duplex communication. Nowadays, Ethernet has adapted to apply in the automotive application. Therefore, it has called for a high degree of testing to ensure the safety and interoperability between these ECUs. However, the testing of the Automotive Ethernet is facing many challenges such as finding and solving the issues as early as possible in the development process. Besides that, testing an Automotive Ethernet TCP/IP stack is a complex task, as it required an upper tester to cause the implementation of the device under the test to move to specific states. AUTOSAR has defined a standardised control protocol (Test Stub) to use it as an upper tester for executing the AUTOSAR Acceptance Test (for TCP/IP stack) [6]. This protocol has used for conducting the test cases of the TCP, UDP and IP protocols in AUTOSAR [21] [22] [23]. OPEN Alliance has specified an Automotive Ethernet ECU test specification which covers more protocols than AUTOSAR such as ARP and DHCP [7]. Consequently, potential gaps and issues may arise when using the Test Stub to conduct the test cases of the OPEN Alliance, as it initially defined for conducting the AUTOSAR Acceptance Test. This work presents the evaluation of the Test Stub in context of using it to conduct the OPEN Alliance Automotive Ethernet ECU Test. Furthermore, it will introduce a solution to overcome the potential issues and gaps which may arise after using the Test Stub (defined by AUTOSAR) to conduct the test cases of the OPEN Alliance.

No description available.

The purpose of this research is to examine the behaviour of elliptical concrete-filled steel tubular stub columns under a combination of axial force and bending moment. Most of the research carried out to date involving concrete-filled steel sections has focussed on circular and rectangular tubes, with each shape exhibiting distinct behaviour. The degree of concrete confinement provided by the hollow section wall has been studied under pure compression but remains ambiguous for combined compressive and bending loads, with no current design provision for this loading combination. To explore the structural behaviour, laboratory tests were carried out using eight stub columns of two different tube wall thicknesses and applying axial compression under various eccentricities. Moment-rotation relationships were produced for each specimen to establish the influence of cross-section dimension and axis of bending on overall response. Full 3D finite element models were developed, comparing the effect of different material constitutive models, until good agreement was found. Finally, analytical interaction curves were generated assuming plastic behaviour and compared with the experimental and finite element results. Ground work provided from these tests paves the way for the development of future design guidelines on the member level.