Dissertations / Theses on the topic 'Hybrid columns'
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NAGUIB, WASSIM IHAB. "LONG-TERM BEHAVIOR OF HYBRID FRP-CONCRETE BEAM-COLUMNS." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin982590541.
Full textShi, Yilei. "Seismic Performance of Hybrid Fiber Reinforced Polymer-Concrete Pier Columns." FIU Digital Commons, 2009. http://digitalcommons.fiu.edu/etd/101.
Full textTrono, William Dean. "Earthquake Resilient Bridge Columns Utilizing Damage Resistant Hybrid Fiber Reinforced Concrete." Thesis, University of California, Berkeley, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3640671.
Full textModern reinforced concrete bridges are designed to avoid collapse and to prevent loss of life during earthquakes. To meet these objectives, bridge columns are typically detailed to form ductile plastic hinges when large displacements occur. California seismic design criteria acknowledges that damage such as concrete cover spalling and reinforcing bar yielding may occur in columns during a design-level earthquake.
The seismic resilience of bridge columns can be improved through the use of a damage resistant hybrid fiber reinforced concrete (HyFRC). Fibers delay crack propagation and prevent spalling under extreme loading conditions, and the material resists many typical concrete deterioration mechanisms through multi-scale crack control.
Little is known about the response of the material when combined with conventional reinforcing bars. Therefore, experimental testing was conducted to evaluate such behaviors. One area of focus was the compression response of HyFRC when confined by steel spirals. A second focus was the tensile response of rebar embedded in HyFRC. Bridge columns built with HyFRC would be expected to experience both of these loading conditions during earthquakes.
The third focus of this dissertation was the design, modeling, and testing of an innovative damage resistant HyFRC bridge column. The column was designed to rock about its foundation during earthquakes and to return to its original position thereafter. In addition to HyFRC, it was designed with unbonded post-tensioning, unbonded rebar, and headed rebar which terminated at the rocking plane. Because of these novel details, the column was not expected to incur damage or residual displacements under earthquake demands exceeding the design level for ordinary California bridges. A sequence of scaled, three dimensional ground motion records was applied to the damage resistant column on a shaking table. An equal scale reinforced concrete reference column with conventional design details was subjected to the same motions for direct comparison.
Compression tests showed that the ductility of HyFRC is superior to concrete in the post-peak softening branch of the response. HyFRC achieved a stable softening response and had significant residual load capacity even without spiral confinement. Concrete required the highest tested levels of confinement to achieved comparable post-peak ductility. Tension tests showed that HyFRC provides a substantial strength enhancement to rebar well beyond their yield point. Interesting crack localization behavior was observed in HyFRC specimens and appeared to be dependent on the volumetric ratio of rebar.
The damage resistant HyFRC bridge column attained its design objectives during experimental testing. It exhibited pronounced reentering behavior with only light damage under earthquake demands 1.5 to 2.0 times the design level. It accumulated only 0.4% residual drift ratio after seven successive ground motions which caused a peak drift ratio of 8.0%. The conventional reinforced concrete column experienced flexural plastic hinging with extensive spalling during the same seven motions. It accumulated 6.8% residual drift ratio after enduring a peak drift ratio of 10.8%.
Massari, Milena. "Hybrid precast concrete dual-shell steel bridge columns under lateral loading." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3054/.
Full textZohrevand, Pedram. "Novel Hybrid Columns Made of Ultra-High Performance Concrete and Fiber Reinforced Polymers." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/627.
Full textKaragiannis, Vasileios. "Behaviour of hybrid timber-steel beam-to-column connections." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/59187.
Full textEder, Martin A. "Inelastic behaviour of hybrid steel/concrete column-to-flat slab assemblages." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/7017.
Full textKhusru, Shovona. "High performance hybrid structural column with rubberised concrete under axial compressive loading." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/233665/1/Shovona_Khusru_Thesis.pdf.
Full textMcLean, Michael M. "Phenyl Functionalized Sol-gel Silica Sorbent for Capillary Microextraction and Chromia-Based Sol-gel Ucon Stationary Phase for Capillary Gas Chromatography." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5374.
Full textNguyen, Cong-Danh. "Workload- and Data-based Automated Design for a Hybrid Row-Column Storage Model and Bloom Filter-Based Query Processing for Large-Scale DICOM Data Management." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC019/document.
Full textIn the health care industry, the ever-increasing medical image data, the development of imaging technologies, the long-term retention of medical data and the increase of image resolution are causing a tremendous growth in data volume. In addition, the variety of acquisition devices and the difference in preferences of physicians or other health-care professionals have led to a high variety in data. Although today DICOM (Digital Imaging and Communication in Medicine) standard has been widely adopted to store and transfer the medical data, DICOM data still has the 3Vs characteristics of Big Data: high volume, high variety and high velocity. Besides, there is a variety of workloads including Online Transaction Processing (OLTP), Online Analytical Processing (OLAP) and mixed workloads. Existing systems have limitations dealing with these characteristics of data and workloads. In this thesis, we propose new efficient methods for storing and querying DICOM data. We propose a hybrid storage model of row and column stores, called HYTORMO, together with data storage and query processing strategies. First, HYTORMO is designed and implemented to be deployed on large-scale environment to make it possible to manage big medical data. Second, the data storage strategy combines the use of vertical partitioning and a hybrid store to create data storage configurations that can reduce storage space demand and increase workload performance. To achieve such a data storage configuration, one of two data storage design approaches can be applied: (1) expert-based design and (2) automated design. In the former approach, experts manually create data storage configurations by grouping attributes and selecting a suitable data layout for each column group. In the latter approach, we propose a hybrid automated design framework, called HADF. HADF depends on similarity measures (between attributes) that can take into consideration the combined impact of both workload- and data-specific information to generate data storage configurations: Hybrid Similarity (a weighted combination of Attribute Access and Density Similarity measures) is used to group the attributes into column groups; Inter-Cluster Access Similarity is used to determine whether two column groups will be merged together or not (to reduce the number of joins); and Intra-Cluster Access Similarity is applied to decide whether a column group will be stored in a row or a column store. Finally, we propose a suitable and efficient query processing strategy built on top of HYTORMO. It considers the use of both inner joins and left-outer joins. Furthermore, an Intersection Bloom filter () is applied to reduce network I/O cost.We provide experimental evaluations to validate the benefits of the proposed methods over real DICOM datasets. Experimental results show that the mixed use of both row and column stores outperforms a pure row store and a pure column store. The combined impact of both workload-and data-specific information is helpful for HADF to be able to produce good data storage configurations. Moreover, the query processing strategy with the use of the can improve the execution time of an experimental query up to 50% when compared to the case where no is applied
Shaw, Tina L. "Hybrid column generation for large network routing problems : with implementations in airline crew scheduling." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/25023.
Full textAbbas, Syed Murtuza. "Advanced Hybrid Simulation Model based on Phenomenology and Artificial Intelligence." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1427963095.
Full textCheng, Ming. "Lot streaming in a two-stage assembly system and a hybrid flow shop." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77197.
Full textPh. D.
Sabharwal, Amish. "A hybrid approach applied to an industrial distillation column that compares physical and neural network modeling techniques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0024/MQ31401.pdf.
Full textCosta, Bruno Xavier da. "Ambiente de simula??o h?brido integrando hysys e rede industrial Foundation Fieldbus aplicado ao controle de uma coluna de destila??o." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15365.
Full textThe main purpose of this work is to develop an environment that allows HYSYS R chemical process simulator communication with sensors and actuators from a Foundation Fieldbus industrial network. The environment is considered a hybrid resource since it has a real portion (industrial network) and a simulated one (process) with all measurement and control signals also real. It is possible to reproduce different industrial process dynamics without being required any physical network modification, enabling simulation of some situations that exist in a real industrial environment. This feature testifies the environment flexibility. In this work, a distillation column is simulated through HYSYS R with all its variables measured and controlled by Foundation Fieldbus devices
O principal objetivo deste trabalho ? desenvolver um ambiente que permite a comunica??o do simulador de processos qu?micos HYSYS R com medidores e atuadores de uma rede industrial Foundation Fieldbus. O ambiente ? considerado h?brido por possuir uma parte real (a rede industrial) e uma parte simulada (o processo) com os sinais de controle e medi??o sendo reais. O ambiente ? bastante flex?vel, permitindo a reprodu??o de diversas din?micas t?picas de processos industriais sem a necessidade de altera??o na rede f?sica, possibilitando gerar diversas situa??es existentes em um ambiente industrial real. No presente trabalho, a din?mica utilizada ? de uma coluna de destila??o, simulada no HYSYS R, com suas vari?veis medidas e controladas pelos dispositivos da rede industrial Foundation Fieldbus
Markowski, Adria Elizabeth. "Planning for Army Force Generation Using Lot Streaming, and Extensions." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/40346.
Full textPh. D.
Bezerra, Leonardo Melo. "Estudo teórico-experimental da ligação entre pilares mistos preenchidos e vigas pré-moldadas de concreto." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-20092011-110345/.
Full textIn this work, connections of precast concrete beam to concrete-filled steel tube column were proposed to transfer the bending moment and shear forces from the beam to the composite column, mobilizing the concrete core. Was performed a numerical and experimental study of the proposed connections to evaluate the feasibility and effectiveness of them in the transfer of bending and shear forces from the beam to the column. In a first stage, models composed by column and steel corbel (models 1 e 2) were numerically and experimentally tested aiming the efficiency of the connection in shear transfer. It was observed that the transfer of shear to the steel tube was guaranteed. The corbel behaved in a predictable way and supported high loads. The use of shear connectors in the column increased the load capacity and improved the connection performance. In next stage of the research work, two models were prepared, composed by: column, precast concrete beam, steel corbel and slabs constituting frames. In one of these models (model 4) a steel box was incorporated into the precast beam and bolted to the steel corbel in order to transfer the positive moments, whereas another model was built and studied without this device (model 3). In this models were evaluated the efficiency in the transfer of bending moments (positive and negative) and shear forces with the models subjected to a cyclic loads. In the model 3, the connection transferred efficiently the negative bending, but the performance for the positive bending was not satisfactory, with reduced strength and stiffness over the load cycles. In model 4 was observed considerable increase in strength and stiffness compared with the previous model. However, the device incorporated in the precast beam was unable to make the connection resist to the positive moments with the same efficiency observed when subjected to the negative moments and a degradation of their structural characteristics was observed during the loading cycles.
D'arisbo, Thiago. "Modelagem híbrida do processo de troca iônica em colunas de leito fixo." Universidade Estadual do Oeste do Parana, 2011. http://tede.unioeste.br:8080/tede/handle/tede/1898.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Ion exchange is a process that is used in the treatment of aqueous industrial effluents containing organic compounds and heavy metals. The fixed bed columns are longer applied by allowing the process to occur continuously (cycles of regeneration). The design and process optimization of the ion exchange column requires the use of mathematical models. Phenomenological models of these systems involve the solution of partial differential and algebraic equations. The equilibrium data for ion exchange processes are usually described by the Mass Action Law (MAL), which can be considered non-ideality of aqueous and solid phases. Artificial Neural Networks (ANN) are being used successfully for the study of equilibrium data because they are empirical models and don t demand a mathematical rigor. This work aimed to evaluate the applicability of the hybrid model to describe the dynamics of ion exchange in fixed beds of binary systems. This system consists of partial differential equations obtained from mass balance in fluid phases in the ion exchanger and ANN to describe the balance. LAM was adjusted to experimental data of ion exchange equilibrium and then were generated 4200 data sets for each binary pair studied, which served as training for RNA. We tested networks with different structures, with one and two input layers. The 3-3-2 structure was used in the simulations of the hybrid model because it was the best represented the systems during the training phase. The differential equations were solved by the lines method. A computer program in FORTRAN language was developed for solving the model equations. DASSL subroutine was used to solve the equations. The performance of the hybrid model was evaluated from the results obtained with the phenomenological model, in which case the equilibrium description was made with the use of MAL. It also was the analysis of results from the comparison of experimental data. To evaluate the model we used data from the literature of ion exchange in Amberlite IR 120 resin on the systems Cu-Na and Zn-Na and in NaY zeolite on Fe-Na and Zn-Na. Both models were efficient to describe the dynamics of ion-exchange fixed bed columns, and the hybrid model had the advantage of the reduced computational time (82% reduction on average) as a result of not needing to solve a nonlinear equation.
A troca iônica é um processo muito utilizado no tratamento de efluentes industriais aquosos contendo compostos orgânicos e metais pesados. As colunas de leito fixo são mais aplicadas por permitir que o processo ocorra de maneira contínua (ciclos de regeneração). O projeto e a otimização de processos de troca iônica em coluna requer o uso de modelos matemáticos. Os modelos fenomenológicos destes sistemas envolvem a resolução de equações diferenciais parciais e algébricas. Os dados de equilíbrio de processos de troca iônica geralmente são descritos pela Lei da Ação das Massas (LAM), na qual podem ser consideradas as não idealidades das fases aquosa e sólida. As Redes Neurais Artificiais (RNA) estão sendo utilizadas com sucesso para o estudo destes dados de equilíbrio por serem modelos empíricos e não demandarem tal rigor matemático. Esta dissertação teve por objetivo avaliar a aplicabilidade do modelo híbrido para descrever a dinâmica do processo de troca iônica em leito fixo de sistemas binários. Este sistema é constituído de equações diferenciais parciais obtidas por meio de balanço de massa nas fases fluida e no trocador iônico e de RNA para descrever o equilíbrio. A LAM foi ajustada a dados experimentais de equilíbrio de troca iônica e, então, foram gerados conjuntos de 4200 dados para cada par binário estudado, os quais serviram como treinamento para a RNA. Foram testadas redes com diferentes estruturas, com uma e com duas camadas de entrada. A estrutura 3-3-2 foi utilizada nas simulações do modelo híbrido, pois foi a que melhor representou os sistemas na etapa de treinamento. As equações diferenciais foram resolvidas pelo método das linhas. Um programa computacional em linguagem FORTRAN foi desenvolvido para a resolução das equações do modelo. Foi utilizada a sub-rotina DASSL para resolver as equações. O desempenho do modelo híbrido foi avaliada a partir dos resultados obtidos com o modelo fenomenológico, sendo que neste caso a descrição do equilíbrio foi feita pelo uso da LAM. Também foi feita a análise dos resultados a partir da comparação dos dados experimentais. Para avaliar o modelo foram utilizados dados da literatura de troca iônica em resina Amberlite IR 120 dos sistemas Cu-Na e Zn-Na e na zeólita NaY dos sistemas Fe-Na e Zn-Na. Ambos os modelos foram eficientes para descrever a dinâmica de troca iônica de colunas de leito fixo, sendo que o modelo híbrido apresentou como vantagem o menor tempo computacional (82% de redução em média) em decorrência de não necessitar resolver a equação não-linear.
Samuelsson, Jörgen. "Development of Methods for Phase System Characterization in Liquid Chromatography." Doctoral thesis, Uppsala universitet, Ytbioteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8597.
Full textDomingues, Diego Soares. "Desenvolvimento de métodos por cromatografia líquida acoplada à espectrometria de massas em tandem para análises de fármacos (LC-MS/MS no modo column switching com capilar monolítico de sílica híbrida), aminoácidos e neurotransmissores (HILIC-MS/MS) em amostras de plasma de pacientes esquizofrênicos." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-03102015-152159/.
Full textSchizophrenia is a chronic neuropsychiatric disorder that affects approximately 1% of the world population. According to neurobiological theories, schizophrenia stems from biochemical and structural alterations in the brain due to dysfunction in the glutamatergic, dopaminergic, and serotonergic systems. Determining the concentrations of amino acids and neurotransmitters in plasma samples from schizophrenic patients may assist evaluation of therapy effectiveness. In addition to antipsychotics (the first-line drug in the initial treatment of schizophrenia), most patients concomitantly use other classes of drugs such as antidepressants, anticonvulsants, and anxiolytics to minimize the symptoms associated with this disease. To evaluate treatment efficacy, in this thesis a method based on protein precipitation (PPT) and hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry (HILIC-MS/MS) has been properly developed and validated to determine amino acids (aspartate, serine, glycine, alanine, methionine, leucine, tyrosine, and tryptophan) and neurotransmitters (glutamate and -aminobutyric acid) in plasma samples obtained from 35 schizophrenia patients treated with clozapine (27 patients) or olanzapine (8 patients); 38 healthy volunteers served as controls. The HILIC-MS/MS method was linear for concentrations ranging from the LLOQ (9.7 pmol mL-1 - 13.3 nmol mL-1) to the ULOQ (19.4 nmol mL-1 - 800 nmol mL-1). The analysis time was 3.0 min. In the case of accuracy, RSE ranged from -18 to 19%. As for precision, CV lay between 0.1 and 16% (LLOQ). Analysis of variance (ANOVA) followed by post-hoc Duncan showed that the average methionine serum levels (nmol mL-1) (F2.70 = 3.14, p = 0.049) in schizophrenic patients treated with olanzapine were significantly higher as compared with the control group (healthy volunteers). The glutamate level in schizophrenic patients treated with clozapine tended to higher values (F2.70 = 2.50, p = 0.090). Concerning the analytical methods, PPT/LC-MS/MS and LC-MS/MS operating in the column-switching mode were developed and validated to determine antipsychotic (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine), antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, and fluoxetine), anticonvulsants (carbamazepine and lamotrigine), and anxiolytics (diazepam and clonazepam) in plasma samples taken from schizophrenic patients for therapeutic drug monitoring. A monolithic hybrid column containing silica with cyanopropyl groups in the first dimension was employed. The PPT/LC-MS/MS method was linear from the LLOQ (0.2 ng mL-1 - 5.0 ng mL-1) to the ULOQ (40.5 ng mL-1 - 10.5 g mL-1). In the case of accuracy, RSE ranged from -9.7 to 8.0%; as for precision, CV lay between 0.1 and 12%. LC-MS/MS in the column-switching mode was linear from the LLOQ (63.0 pg mL-1 - 1250.0 pg mL-1) to the ULOQ (40.5 ng mL-1 - 10.5 g mL-1). RSE ranged from -14 to 12%; CV lay between 0.6 and 6.5%. The drugs were selectively pre-concentrated in the monolithic column containing silica incorporated with cyanopropyl groups. For the LC-MS/MS method operating in the column-switching mode, the endogenous components of the biological sample of the LC-MS/MS method were removed before analysis. Analysis of 10 plasma samples obtained from schizophrenic patients did not reveal any significant differences (t test) between the LC-MS/MS method and the reference PPT/LC-MS/MS method. Therefore, LC-MS/MS can be applied in therapeutic monitoring, with the advantage that this method offers improved precision, accuracy, and analytical frequency.
Trotta, André Marcon. "Estudo experimental de uma ligação viga-pilar em concreto pré-moldado utilizando perfis metálicos e solda." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-10122012-085143/.
Full textIn this research the behavior of a beam-column connection in precast concrete system using welded steel shapes built-in structural elements was studied. The model of the studied connection allows transmission of positive and negative moments. For the continuity of negative moment, is used a steel \"U\" shaped corbel inserted in the column welded with tubular section steel hangers inserted in each beam. For the continuity of positive moment, use is made of metal embedded in abutment ledges that are welded to the positive reinforcement of the beam. The study consisted on experimental analysis of a cross-shaped specimen in two steps. In the first step was applied to the specimen a cyclic load using hydraulic actuator coupled to the column head. In the second step was applied in the specimen a static load using hydraulic jack positioned under the column to cause rupture with negative moment. The connection model showed a considerably easy assembly, as in the transitional phase the connection is articulated and the steel \"U\" shaped corbel of the column allows the lateral stability of the beam. The rupture occurred by yielding of the steel U shaped corbel in the section near the column. The steel corbel inserted in the column yielded before reaches the resistant capacity of other components of the connection, because of the section in the connection close of the column, only steel corbel resists the negative moment.
Melega, Gislaine Mara [UNESP]. "Problema integrado de dimensionamento de lotes e corte de estoque: modelagem matemática e métodos de solução." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150002.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Nesta tese, estamos interessados em tratar de maneira integrada dois conhecidos problemas da literatura. Esta integração é referida na literatura como problema integrado de dimensionamento de lotes e corte de estoque. A ideia consiste em considerar simultaneamente, as decisões relacionadas com ambos os problemas, de modo a capturar a interdependência entre estas decisões e, assim, obter uma melhor solução global. Propõe-se um modelo matemático geral para o problema integrado de dimensionamento de lotes e corte de estoque (GILSCS), que considera vários níveis de integração e nos permite classificar a literatura, em termos de modelos matemáticos, dos problemas integrados. A classificação é organizada a partir de dois principais aspectos de integração que são: a integração através dos períodos de tempo e a integração entre os níveis de produção. Em um horizonte de planejamento que considera vários períodos, o estoque fornece uma ligação entre os períodos. Esta integração, por períodos de tempo, constitui o primeiro tipo de integração. O problema geral também considera a produção em diferentes níveis: objetos são fabricados ou comprados e então são cortados para produzir peças menores e estas, por sua vez, constituem componentes para a produção dos produtos finais. A integração entre os diferentes níveis de produção consiste no segundo tipo de integração. A revisão da literatura também possibilita direcionar interessantes áreas para pesquisas futuras. O comportamento da solução para este tipo de problema, com três níveis e vários períodos, é estudado a partir do desenvolvimento de métodos de solução considerando abordagens que superam as dificuldades do problema, que consistem no alto número de padrões de corte, estruturas em vários níveis (multiestágios) e variáveis binárias de preparo. Os métodos de solução propostos para o problema GILSCS são baseados em duas abordagens conhecidas da literatura, usadas com sucesso para resolver os problemas separadamente, que são o procedimento de geração de colunas e heurísticas de decomposição do tipo relax-and-fix. Estas estratégias e suas variações são combinadas à um pacote de otimização em um estudo computacional com dados gerados aleatoriamente. Uma revisão da literatura, em termos de métodos de solução, para o problema integrado também é apresentada. Outras contribuições desta tese consistem em propor diferentes modelos matemáticos para o problema integrado, combinando modelos alternativos para cada um dos problemas separadamente. Neste estudo, o objetivo é comparar e avaliar, com um extensivo estudo computacional, a qualidade e o impacto das diferentes formulações. O outro trabalho trata de uma aplicação do problema integrado em um indústria de móveis de pequeno porte, em que restrições específicas do ambiente industrial são abordadas, como estoque de segurança e ciclos da serra. A solução obtida pelo modelo proposto é comparada com uma simulação da prática da empresa.
In this thesis, the subject of interest is in treating, in an integrated way, two wellknown problems in the literature. This integration is referred in the literature as the integrated lot-sizing and cutting stock problem. The basic idea is to consider, simultaneously, the decisions related to both problems so as to capture the interdependency between these decisions in order to obtain a better global solution. We propose a mathematical model for a general integrated lot-sizing and cutting stock (GILSCS) problem. This model considers multiple dimensions of integration and enables us to classify the current literature, in terms of mathematical models, in this field. The main classification of the literature is organized around two types of integration. In a planning horizon which consists of multiple periods, the inventory provides a link between the periods. This integration across time periods constitutes the first type of integration. The general problem also considers the production in different levels: objects are fabricated or purchased and then, they are cut to produce the pieces which are then assembled as components in the production of final products. The integration between these production levels constitutes the second type of integration. The literature review also enables us to point out interesting areas for future research. The behavior of a solution to this type of problem, with three levels of production and several time periods, is studied considering the development of solution approaches that overcome the difficulties of the problem, which are the high number of cutting patterns, multi-level structures and the binary values of the setup variables. The solution methods proposed to the GILSCS problem are based on two known strategies from the literature which are used successfully to solve the problems separately, which are the column generation procedure and decomposition heuristics based on relax-and-fix procedure. These strategies and their variations are combined into an optimization package in a computational study with randomly generated data. A literature review, in terms of solution methods, to the integrated problem, is also presented. Other contributions of this thesis consist of proposing different mathematical models for the integrated problem combining alternative models for each one of the problems separately. In this study, the aim is to compare and evaluate, with an extensive computational study, the quality and the impact of these dfifferent formulations. Another study is an application of the integrated problem in a small furniture factory, in which specific constraints related to the industrial environment are addressed, such as, safety stock level constraints and saw cycles constraints. The solution obtained from the proposed model is compared to a simulation of the common practice in the company.
FAPESP: 2012/20631-2
Lin, Tsung-Te, and 林宗德. "The Retrofit of Reinforced Concrete Bridge Columns Using Hybrid Carbon Fiber Composites." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/52339054057774467509.
Full text逢甲大學
土木工程所
100
In this thesis, the experimental and theoretical results of circular section reinforced concrete (RC) bridge columns retrofitted by Hybrid Carbon Fiber Composites preformed jacketing were introduced. The design of the RC circular bridge columns was based on the old (before 1995) bridge seismic design codes in Taiwan (MOTC, 1987).The benchmark tests of bridge column with flexural failure modes as tested in the National Center for Research on Earthquake Engineering (NCREE). A scale down concrete column with a diameter of 0.6 m and 2.2 m in height incorporated with insufficient axial reinforcement was designed as the prototype to test its seismic resistance during cyclic lateral loadings. Concrete column was laterally cyclic loaded till the main bar reached the initial yielding, and then retrofitted with hybrid CFRP preformed jacket was laterally pushed to evaluate its seismic resistance. In addition, an undamaged concrete column same as the prototype was retrofitted directly to upgrade its ductility during the earthquake. From the cyclic lateral push-over test, it shows that the hybrid CFRP preformed jacket can increase the peak lateral forces by 12.9 % and 18.9 %, respectively for the pre-damaged and upgraded concrete columns. The seismic ductility can increase 54.3 % and 153.9 %, respectively. This hybrid CFRP preformed jacket can improve the ductility of bridge columns without changing their original structural behaviors. The preformed hybrid CFRP jacket can also save the time of rehabilitation and have good control of the material properties in the factory.
Σκαλωμένος, Κωνσταντίνος. "Seismic performance of plane moment resisting frames with concrete filled steel tube columns and steel I beams." Thesis, 2014. http://hdl.handle.net/10889/8442.
Full textΟ σκοπός της παρούσας έρευνας είναι να διερευνήσει τη σεισμική συμπεριφορά επίπεδων καμπτικών πλαισίων με υποστυλώματα από τετραγωνικές χαλύβδινες κοιλοδοκούς γεμισμένες με σκυρόδεμα και με μεταλλικές δοκούς τύπου Ι και να προτείνει μία μέθοδο αντισεισμικού σχεδιασμού με βάση την επιτελεστικότητα για αυτόν τον τύπο κατασκευών. Αρχικά, διεξάγεται μία υπολογιστική μελέτη ώστε να διερευνηθεί η μη-γραμμική ανελαστική απόκριση υπό ανακυκλιζόμενη φόρτιση και σταθερή θλίψη των τετραγωνικών σύμμικτων υποστυλωμάτων. Ένα ακριβές και προηγμένο μοντέλο πεπερασμένων στοιχείων δημιουργείται όπου η ακρίβεια των αποτελεσμάτων του ελέγχεται μέσω συγκρίσεων των αναλυτικών λύσεων με υπαρκτά πειραματικά δεδομένα. Κατόπιν, χρησιμοποιώντας αυτό το μοντέλο πεπερασμένων στοιχείων, πραγματοποιoύνται εκτενείς παραμετρικές μελέτες με σκοπό να παραχθούν πληροφορίες σχετικά με την υστερητική συμπεριφορά των σύμμικτων υποστυλωμάτων. Έτσι, στη βάση αυτής της υπολογιστικής μελέτης, τρία απλά και αρκετά ακριβή υστερητικά μοντέλα συγκεντρωμένης πλαστιμότητας αναπτύσσονται για την προσομοίωση της συμπεριφοράς σύμμικτων υποστυλωμάτων υπό ανακυκλιζόμενη φόρτιση και σταθερή θλίψη. Έπειτα, διερευνάται η σεισμική συμπεριφορά επίπεδων καμπτικών πλαισίων με σύμμικτα υποστυλώματα και με μεταλλικές δοκούς τύπου Ι. Πιο συγκεκριμένα εξετάζεται η επίδραση της λεπτομερής μοντελοποίησης των επιμέρους δομικών στοιχείων μια κατασκευής, όπως των σύμμικτων υποστυλωμάτων, των μεταλλικών δοκών, των κόμβων διατμητικής παραμόρφωσης και των συνδέσεων, στη σεισμική συμπεριφορά των πλαισίων μέσω συγκρίσεων με υπαρκτά πειραματικά δεδομένα. Επιπλέον, διαμορφώνονται καμπύλες τρωτότητας για τρία σύμμικτα πλαίσια σχεδιασμένα με τους Ευρωπαϊκούς κανονισμούς για διάφορα επίπεδα μοντελοποίησης χρησιμοποιώντας μη-γραμμικές αναλύσεις χρονοιστορίας. Στη βάση αυτών των καμπυλών τρωτότητας, κάποιος μπορεί να επιλέξει το κατάλληλο επίπεδο πολυπλοκότητας της μοντελοποίησης των σύμμικτων πλαισίων ώστε να οδηγηθεί στην επιθυμητή συμπεριφορά για μια δεδομένη σεισμική ένταση. Το τρίτο μέρος της παρούσας έρευνας πραγματεύεται την ανάπτυξη της διαδικασίας που απαιτείται από την Υβριδική Δυνάμεων-Μετατοπίσεων (ΥΔΜ) μέθοδο αντισεισμικού σχεδιασμού με βάση την επιτελεστικότητα, η οποία συνδυάζει τα πλεονεκτήματα της μεθόδου των δυνάμεων και της μεθόδου των μετακινήσεων, ώστε να εφαρμόζεται για τον αντισεισμικό σχεδιασμό σύμμικτων καμπτικών πλαισίων. Έτσι, πραγματοποιούνται εκτενείς παραμετρικές μελέτες περιλαμβάνοντας μη-γραμμικές δυναμικές αναλύσεις σε 96 πλαίσια υπό 100 σεισμικές καταγραφές με σκοπό τη δημιουργία τράπεζας δεδομένων με αποκρίσεις ενδιαφέροντος. Κατόπιν αναλύσεων γραμμικής παλινδρόμησης, απλές σχέσεις προτείνονται που απαιτούνται από την ΥΔΜ μέθοδο οι οποίες συνδέουν τη μέγιστη μετακίνησης κορυφής των πλαισίων με τη στοχευόμενη μέγιστη γωνιακή παραμόρφωσης των ορόφων ή την τοπική στροφική πλαστιμότητα των μελών και την απαιτούμενη συνολική πλαστιμότητας του πλαισίου με τον συντελεστή συμπεριφοράς q. Η σύγκριση της προτεινόμενης ΥΔΜ μεθόδου αντισεισμικού σχεδιασμού με εκείνης που προτείνεται από τον Ευρωπαϊκό κανονισμό αποδεικνύει ότι η προτεινόμενη διαδικασία φαίνεται να είναι πιο ακριβής και ελέγχει καλύτερα τις παραμορφώσεις. Μη-γραμμικές αναλύσεις χρονοιστορίας δείχνουν την συνέπεια της ΥΔΜ να εκτιμά με ακρίβεια τις απαιτήσεις των ανελαστικών παραμορφώσεων στα διάφορα επίπεδα επιτελεστικότητας σε αντίθεση με την τάση του κανονισμού να υποεκτιμά τη μέγιστη γωνιακή μετακίνησης ορόφων και να υπερεκτιμά την μέγιστη μετακίνηση κορυφής. Τέλος, συγκρίσεις σύμμικτων πλαισίων με σχεδιασμένα πλαίσια εξ’ ολοκλήρου από χάλυβα σύμφωνα με την ΥΔΜ, δείχνουν ότι τα σύμμικτα πλαίσια έχουν καλύτερη σεισμική συμπεριφορά από τα μεταλλικά και φαίνεται να είναι πιο οικονομικές κατασκευές.
Barbosa, Vítor. "Bus driver rostering by hybrid methods based on column generation." Doctoral thesis, 2018. http://hdl.handle.net/10451/35192.
Full textRostering problems arise in a diversity of areas where, according to the business and labor rules, distinct variants of the problem are obtained with different constraints and objectives considered. The diversity of existing rostering problems, allied with their complexity, justifies the activity of the research community addressing them. The current research on rostering problems is mainly devoted to achieving near-optimal solutions since, most of the times, the time needed to obtain optimal solutions is very high. In this thesis, a Bus Driver Rostering Problem is addressed, to which an integer programming model is adapted from the literature, and a new decomposition model with three distinct subproblems representations is proposed. The main objective of this research is to develop and evaluate a new approach to obtain solutions to the problem in study. The new approach follows the concept of search based on column generation, which consists in using the column generation method to solve problems represented by decomposition models and, after, applying metaheuristics to search for the best combination of subproblem solutions that, when combined, result in a feasible integer solution to the complete problem. Besides the new decomposition models proposed for the Bus Driver Rostering Problem, this thesis proposes the extension of the concept of search by column generation to allow using population-based metaheuristics and presents the implementation of the first metaheuristic using populations, based on the extension, which is an evolutionary algorithm. There are two additional contributions of this thesis. The first is an heuristic allowing to obtain solutions for the subproblems in an individual or aggregated way and the second is a repair operator which can be used by the metaheuristics to repair infeasible solutions and, eventually, generate missing subproblem solutions needed. The thesis includes the description and results from an extensive set of computational tests. Multiple configurations of the column generation with three decomposition models are tested to assess the best configuration to use in the generation of the search space for the metaheuristic. Additional tests compare distinct single-solution metaheuristics and our basic evolutionary algorithm in the search for integer solutions in the search space obtained by the column generation. A final set of tests compares the results of our final algorithm (with the best column generation configuration and the evolutionary algorithm using the repair operator) and the solutions obtained by solving the problem represented by the integer programming model with a commercial solver.
Programa de Apoio à Formação Avançada de Docentes do Ensino Superior Politécnico (PROTEC), SFRH/PROTEC/67405/2010
Hui, Yi-Hausn, and 惠一軒. "Optimal Manufacturing Processes of Silts Recycle to Manufacture Columnar Body of Hybrid Materials with Lake and River Silts." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/kp8ten.
Full text大葉大學
工具機產業碩士學位學程
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The problem of sludge piling up in Taiwan reservoir is more critical. The sludge which piling up in reservoir reduced the total capacity of Taiwan reservoir, and it will make reservoir break up easier. The piling sludge also created the problem about water pollution. The solution with these problems would spent much money. Therefore, this program was studying the characteristic of sludge to clean up the reservoir effectively and recycle it by spending less money. We try to use sludge displaying aggregate of concrete works. For reduce the cost we study the effect of sludge displaying aggregate of concrete works by the results of slump test, flow test, air content test, compressive strength test, absorption and permeability test, we study the effect of sludge displaying aggregate of concrete works. When we increase the number of Silt’s replacement, would makes compression strength have some decrease. But the compression strength is designed 280 kgf/cm2, the compression strengths are correspond with specification of concrete process that application in clipping block process or bulwark process with concrete. We is used erosion test to compare the difference of normal concrete to find out that the mass of silt-concrete, which undergo erosion process, were similar with normal concrete. But the cost of normal concrete are much expensive than silt-concrete, so that we could lower the price of cost efficiently. As a result, from all the consequence of test the property were not too much different between silt-concrete and normal concrete. But it has very good effect on the profit of silt-concrete process. Especially on clipping block and bulwark process, can give full play to their functions
Ng, Evelyn. "Strengthening Mechanisms in Microtruss Metals." Thesis, 2012. http://hdl.handle.net/1807/34825.
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