abstract: Nowadays product reliability becomes the top concern of the manufacturers and customers always prefer the products with good performances under long period. In order to estimate the lifetime of the product, accelerated life testing (ALT) is introduced because most of the products can last years even decades. Much research has been done in the ALT area and optimal design for ALT is a major topic. This dissertation consists of three main studies. First, a methodology of finding optimal design for ALT with right censoring and interval censoring have been developed and it employs the proportional hazard (PH) model and generalized linear model (GLM) to simplify the computational process. A sensitivity study is also given to show the effects brought by parameters to the designs. Second, an extended version of I-optimal design for ALT is discussed and then a dual-objective design criterion is defined and showed with several examples. Also in order to evaluate different candidate designs, several graphical tools are developed. Finally, when there are more than one models available, different model checking designs are discussed. / Dissertation/Thesis / Ph.D. Industrial Engineering 2013

O objetivo deste trabalho é analisar a influência dos parâmetros de um sistema mecanizado de soldagem, composto por uma tocha TIG e outra MAG em tandem, sobre a geometria do cordão de solda resultante. Os resultados obtidos foram comparados com soldas realizadas pelos processos TIG e MAG operando isoladamente. Os testes foram executados por meio de simples deposição de cordões sobre chapas de aço ao carbono AISI 1010 com espessura de 6,3 mm. Os parâmetros analisados foram: corrente de soldagem e distância da ponta do eletrodo até a peça no processo TIG, velocidade de alimentação de arame e tensão do arco no processo MAG, além de velocidade de soldagem e distância entre as tochas. Os cordões de solda foram executados em um dispositivo de soldagem mecanizado, que permite a variação da velocidade de soldagem, distância da ponta do eletrodo TIG e a distância entre as tochas. Os ajustes de corrente e tensão de soldagem foram feitos em duas fontes de potência separadas, ambas do tipo transformador-retificador, uma para cada tocha, devido às diferentes curvas características de cada processo. Através do projeto de experimento fatorial fracionado, foram avaliados os efeitos de dois níveis, um mínimo e outro máximo, mais quatro réplicas dos seus níveis intermediários, resultando em 20 experimentos para cada processo de soldagem. Os valores dos resultados finais indicam uma diferença ao utilizar uma tocha TIG para pré-aquecer o material base, porém, estatisticamente, essa diferença não é significativa entre os processos TIG e MAG em tandem e MAG convencional para a faixa de parâmetros de soldagem adotada. / This study aims to investigate the influence of process parameters of a mechanized welding system, comprising a GTAW torch and a GMAW torch in tandem configuration, on the geometry of the resulting weld bead, performed using GTAW and GMAW welding processes in tandem. The results were compared with weld beads performed by conventional GTAW and GMAW welding processes. The tests were conducted performing bead-on-plate deposits over AISI 1010 6,3 mm thick carbon steel plates. GTAW current, GMAW wire feed speed, GTAW arc length, GMAW voltage, welding speed and the distance between GTAW and GMAW torches were the analyzed parameters. The weld beads were performed in a mechanized welding bench, which allows the variation of speed, distance between torches and arc length of the GTAW torch. Current and voltage adjustments were made in two separate transformer-rectifier power sources, one for each welding torch, due to their different characteristic curves of each process. Through the fractional factorial design of experiment, the effects of two different levels for each parameter were analyzed, plus four replicates of the average values of these levels, resulting in 20 experiments for each welding process. The results show a difference on the weld bead geometry using a GTAW torch to preheat the base metal, however, this difference is not statistically significant between GTAW and GMAW welding process in tandem and GMAW welding process for the adopted range of welding parameters.

O objeto desta dissertação é a estrutura de preferência do consumidor (EPC). O objetivo geral é estudar os métodos de mensuração da EPC (MMEPC) e o tema é a mensuração desta estrutura, utilizando a técnica estatística Conjoint Analysis (CA). A CA proporciona uma maneira realista de medir o impacto de cada atributo de um produto na preferência do consumidor. Esta técnica estatística tem sido cada vez mais aplicada em problemas de Marketing. Alguns softwares têm surgido e provocado o aumento de uso desta técnica. A dissertação discute uma aplicação real desta técnica num problema de definição de um tecido de linho ótimo para um conjunto de especialistas. A ênfase está no planejamento do experimento fatorial fracionário para a estimação do modelo individual cuja variável resposta é posto e os atributos são qualitativos. Modelos lineares de célula de referência e de desvios foram construídos para a análise do experimento. Utilizou-se o modelo linear aditivo não-saturado. Alguns dos principais softwares foram analisados: SPSS, SAS, ACA, CBC e CVA. O autor define um projeto de software de planejamento de experimentos fatoriais fracionários ótimos segundo a eficiência-D. O estudo dos MMEPC pode proporcionar as seguintes contribuições à Administração: otimização de projetos de produtos/serviços/conceitos, quantificação da EPC, segmentação de mercado, determinação da probabilidade de escolha ou participação esperada do mercado de produtos/serviços/conceitos num determinado cenário e simulação (predição) de preferências individuais e agregadas. / The purpose of this dissertation is the consumer’s preference structure (CPS). The general objective is to study the methods of mensurement of CPS (MMCPS) and its main purpose is to measure that structure using the statistical technique Conjoint Analysis (CA). The CA provides a realistic way to measure the impact of the attribute of a product on the consumer’s preference. This statistical technique is being used more and more in marketing problems. Some softwares have emerged and increased the use of this technique. This dissertation discusses a real application of this technique on the problem of definition of a linen tissue for a specialist group. The emphasis is on the design of a fractional factorial experiment for estimation of a individual model in wich the response variable is rank and the attributes are qualitative. Linear models of a cell of reference and deviations were constructed for the experimental analysis. Used one a non satureded linear model. Some of the main softwares were analysed: SPSS, SAS, ACA, CBC and CVA. The author defines a software project for optimum fractional factorial experimental design and analysis, according to D-efficiency. MMCPS studies can provide the following contribution to Management: products/services/concepts optimization, CPS quantification, marketing segmentation, choice probability determination on the expected participation of the products/services/concepts market in a particular scenario and the simulation (prediction) of individual and aggregate preferences.

Laser technologies have made distinguished contributions to modern industry. These have typically been realised through the important role played by lasers in the advancement of manufacturing technology in many areas such as welding, which has become an important joining technique and thus promoted the use of lasers in a wide variety of applications in the oil, gas, aerospace, aircraft, automotive, electronics and medical industries. A detailed review of previous work in the use of lasers for advanced manufacturing, and in particular, laser beam welding is given. The work reported in this thesis aims to develop a new method of laser welding. This is connected with investigations relating to the production of net shape welds for bead-on-plate welding and butt welding of mild steel plates. Based on the nature of its operation, use of a fibre laser was considered most suitable compared to other solid state lasers. Net-shape welds were demonstrated on mild steel plates using an IPG 1 kW single mode fibre laser with a maximum power output of 1000 W.The thesis shows results from experimental and modelling (based on finite element and computational fluid dynamic modelling) to validate the idea and the understanding of underlying scientific principles. The thesis is presented in the form of a collection of published work generated by the author during the course of this project. In addition, some results that are not yet published are also included. Design of experiments and statistical modelling has been used in the experimental work to understand the process parameter interactions. Microstructural and mechanical testing have been carried out to evaluate the performance of the welds. Net shaped (the weld bead is flat to the parent material surface) welds have been achieved and compared with standard welds. The understanding of net-shape weld formation and the effect of the laser welding parameters was enhanced by the theoretical modelling. The thesis concludes with a summary of scientific findings and an overview of future work.

Indiana University-Purdue University Indianapolis (IUPUI) / Suboptimal dosing of anti-microbial agents increases the likelihood of therapeutic failure and resistance. Dosing optimization, while an attractive approach to combat these issues, is difficult to implement due to the different pharmacokinetics of each individual. These limitations highlight the inadequacies of a “standardized” dosing strategy. Therapeutic drug monitoring (TDM) provides a tailored treatment for individuals while avoiding adverse side effects from compounds with a narrow therapeutic window where elevated concentrations of a drug cause organ toxicity. This strategy involves accurately measuring the concentration of the analyte and interpreting the results based on pharmacokinetic parameters. Clinicians then draw conclusions regarding dose adjustment for their patient. However, TDM is expensive and difficult to perform because measurements occur in biofluids. Rapid and robust methods are necessary to quantify antimicrobial agents at the institutional level to guide patient care toward improved outcomes in serious infection. Paper spray ionization (PS), an emerging ambient ionization technique for clinical settings, demonstrations a wide versatility both in analyte variety and applications. This technique offers a rapid, accurate method to analyze these compounds with low rates of false positives even when multiplexing. The work herein explains the method development of assays for TDM of various antimicrobial agents. Chapters two and three describe ways to improve the quantitative capability of paper spray through substrate pre-treatment, modification, and manipulation of key factors. Chapter four describes real-world applications for paper spray utility in clinical settings with the cross-validation of antifungal agents against a “gold standard” method. The final chapter, while not clinical based, describes the method development process for a LC-MS/MS assay to detect urobilinoids in fly guts.

The diploma thesis deals with the influence of the volumetric accuracy of the machine tool on the size of the assessed work space. The impact assessment was carried out on the basis of tests of a three-axis vertical CNC machining center. The thesis is divided into two parts, theoretical and practical. The theoretical part is focused on geometric / volumetric accuracy of machine tools, measuring technique for measuring geometric errors and Design of Experiment. In the practical part, there is an analysis of the Design of Experiment according to Shainin, description of the work with the measuring instruments and the measurement of the geometric / volumetric accuracy of the machine including statistical evaluation. The output of the thesis is the description of the influence of volumetric deviation on the size of the measured work space by means of statistical methods.

In this thesis, the design of experiment is studied. Firstly, a theoretic background in mathematical statistics necessary for understanding is built (chapter 2). The design of experiment is then presented in chapters 3 and 4. Chapter 3 is divided into several subchapters in which its brief history is provided as well as its complex theoretic description (basic principles, steps for planning, etc.). Chapter 4 deals with particular types of the design of experiment (Factorial experiments or Response surface design). Simple examples are provided to illustrate the theory in chapters 3 and 4. Last part of the thesis is strictly practical and focuses on an application of the theory for particular data sets and its evaluation (chapter 5).

In the past few decades, brake pad-rotor interface friction studies have gained high importance in the automotive industry. The goal of these studies has been to improve the design to maximize the contact area and performance in brakes. In these studies, friction coefficient has always assumed to be the same for linear and rotational motion. In our study, we show that the rotational and linear friction process have different friction coefficients. We use semi-metallic and ceramic brake material pads reduced into brake samples using scaling laws of physics. The samples were mounted on the Universal Mechanical Tester and experimented for linear and rotational friction process against Pearlitic Gray cast iron rotor. From results, it proved friction coefficients of linear movement is always higher than the rotational movement. The linear friction coefficient was found to be 43% higher on an average than the rotational friction coefficient in both the materials tested at 1MPa and 10 mm/s. These results will help industry in gaining better fundamental understanding about the friction coefficients of rotor- brake contact interfaces.

No description available.

The thesis presents a rational path for the optimization of the selection of optical treatment parameters in photobiomodulation of human skin fibroblasts. The project begins with an extensive analysis of 90 bibliographic reports in photobiomodulation published between 1985 and 2015, and revealed major inconsistencies in optical parameters selected for clinical applications. Seeking greater clarity for optimal parameter choice, a systematic approach to disentangle the multiple factors underpinning the response of human dermal fibroblasts in vitro to visible and near-infra red (NIR) light was employed. Light-based devices were constructed to specifically and systematically screen the optical parameter window (i.e. wavelength, irradiance and dose) observed in literature. Additionally, critical culture and treatment conditions that have dramatic impact on the outcome of specific light treatment of these human skin dermal cells were identified. In particular, environmental oxygen concentration, cell confluency and serum concentration were all found to have a great effect on the response of dermal fibroblasts to light. In parallel, the induction of reactive oxygen species (ROS) by short visible wavelengths on two dermal fibroblast sub-populations or lineage, reticular and papillary, was monitored by live-cell imaging. The ROS species were found to be created in or close to mitochondria. Lastly, gene expression studies revealed a strong impact of short visible wavelengths, as compared to long and NIR wavelengths on both subpopulations of human dermal fibroblasts. In particular, blue light (450 nm) specifically down-regulated proliferation, metabolism and protein synthesis molecular pathways. At the protein level, 450-nm light inhibited the production of procollagen I in human reticular and papillary fibroblasts in a dose-dependent manner. Gene expression results were in agreement i.e., the same light parameter down-regulated collagen fiber genes, integrins and up-regulated collagenase MMP1. This thesis concludes with a chapter presenting a characterization of the accuracy of a potential translation tool for the prediction of optical photon density inside human skin. / Marie Skłodowska-Curie Actions.