Dissertations / Theses on the topic 'An engineer'

In this research an approach to all optical delta sigma modulator (ADSM) has been elaborated. Two important components of ADSM; "leaky integrator" and "inverted bi-stable quantizer" were modeled, on the basis of cross gain modulation of the Semiconductor Optical Amplifier (SOA). The simulations (via VPI photonics) were all in micrometer scale (suitable for chip fabrication). By simulating each element of ADSM the whole circuit was simulated and results have been showed and analyzed. By investigating the ADSM, the limiting factor for reaching higher frequencies (THz) was recognized to be the quantization device. Thus a new optical switch was introduced, for the first time so called "proteresis." By applying proteretic bi-stable device in the delta sigma modulator, the resonance frequency was improved minimum two fold from 295MHz to 575MHz without making any change in hysteretic bi-stable switch. The broad impact of this research is on the digital technologies that can be utilized in high-speed signal processing. The prime examples are the RF technologies used in military and civilian applications. Furthermore introduction of proteresis opens a new research gate for compensating delay in almost every system.

Before the introduction of degree programmes in 1983, the route followed by technician engineers being trained in Hong Kong, particularly at the Hong Kong Polytechnic, was quite unique. About 680 students are admitted into the eight Higher Diploma engineering programmes at Higher Technician level each year at the Hong Kong Polytechnic. The students first took a three-year Higher Diploma programme, continued for a one-year Associateship programme and finally sat the Engineering Council Part II Examinations, thus fulfilling the academic requirements for Chartered Engineer status.

Im Vortrag werden alle derzeit bestehenden Simulations-Werkzeuge im Überblick vorgestellt und deren Anwendung an einzelnen Beispielen verdeutlicht. Desweiteren beinhaltet der Beitrag die Vorstellung der wesentlichen Neuerungen der Pro/ENGINEER Version Wildfire 5 auf dem Gebiet Simulation. Dabei wird auf die Dynamische Analyse und die Erweiterungen in Mechanica besonders eingegangen.

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Este trabalho trata de alguns aspectos da obra de Ruy Cinatti, poeta que dentro do vasto panorama da poesia portuguesa do século XX destaca- se pela sua singularidade. Sua poesia, bem como seus estudos científicos, evidenciam a preocupação e o conhecimento do autor com relação às questões ecológicas e antropológicas, que se refletem nas suas posições políticas. Seus escritos figuram como instrumentos de denúncia contra a má utilização dos recursos naturais e da exploração do ser humano, relacionadas com a colonização portuguesa, bem como as inúmeras intervenções que Timor sofreu ao longo de sua história. Com sua formação científica interdisciplinar (silvicultor, antropólogo e engenheiro agrônomo) Ruy Cinatti tinha uma grande capacidade de enxergar a relação do homem com o meio em que vive de forma ampla e abrangente. Estas idéias refletem-se a todo momento nos poemas que dedicou a Timor. Em constantes viagens para reconhecimento do território, Cinatti intensificou sua relação com os timorenses. Isso só foi possível graças ao fato de ele ter transcendido o papel de português colonizador e ter conseguido aproximar-se do timorense de uma forma particular, a ponto de ser aceito pelos nativos como um irmão, o que se comprova pelo pacto de sangue que celebrou com dois chefes timorenses. A visão interdisciplinar e sensível do mundo torna sua obra poética e científica especial e singular, fazendo de Ruy Cinatti personagem fundamental na literatura portuguesa.
This thesis concerns some aspects of the work of Ruy Cinnati, a poet whose singularity makes him an outstanding figure in the rich panorama of twentieth-century Portuguese poetry. His poems, as well as his scientific studies, testify to the author s interest and knowledge of environmental and anthropological issues, which are reflected in his political positions. His writings are expos s of the misuse of natural resources and the exploitation of human beings under Portuguese colonization, as well as of the countless interventions suffered by East Timor throughout its history. Thanks to his interdisciplinary scientific training (as a forest expert, an anthropologist and an agronomist) Ruy Cinatti was uniquely able to see man s relationship with the environment. These ideas are clearly present in the poems he dedicated to Timor. In his many surveying trips, Cinatti intensified his relations with the Timorese. This was made possible by his ability to transcend the role of the Portuguese colonizer and to get close to the Timorese to the point of being accepted by the natives as a brother witness the blood pact he celebrated with two Timorese chiefs. His interdisciplinary and sensitive worldview makes his poetic and scientific work rather special and unique, so that Ruy Cinatti has become a fundamental name in Portuguese literature.

This thesis project is about a television engineer in the Department of Radio, Television and Film at the University of North Texas. This project records the engineer's activities in the Department and interviews him about his career path. An accompanying written production report describes the pre-production, production and post-production processes of this project.

I Am a Lonely Engineer is a collection of poems dealing with the emotional fallout of a speaker whose life has been uprooted by the absence of his father. Through a series of semi-surreal narratives, the speaker eventually comes to terms with his father's absence and begins the process of healing in the wake of this familial trauma.
Master of Fine Arts

Designing a biosensor capable of continuously monitoring blood glucose concentration in people with diabetes has been a major challenge for over three decades. In this work we attempt to develop a novel microspike based minimally invasive biosensor for this purpose. Also, as a part of an ongoing study, we attempt to improve the current design of coil-type implantable biosensors. Microspikes, which are able to painlessly penetrate the skin layer, were fabricated using lithographic techniques and sputtered with gold to serve as an electrode. The biosensor design is based on thiomalic acid self-assembled monolayer (SAM) on which glucose oxidase was immobilised by a simple coupling technique together with a tetrathiafulvalene mediator entrapped in an epoxy-polyurethane permselective membrane. Functional testing revealed that such modified sensors are capable of detecting glucose concentration within the clinically relevant range. This was followed by studying the microspike based biosensors incorporated into the microfluidics platform mimicking the sensor behaviour in interstitial fluid. Data from these experiments revealed that the sensor response is mainly dependent on enzyme kinetics rather than membrane permeability to glucose. In contrast, an attempt to address the reproducibility issues of coil-type biosensors is presented. The hypothesis for this study was that a crosslinked hydrogel would have a sufficiently uniform porosity and hydrophilicity to address the variability in sensor sensitivity. The hydrogel was prepared by crosslinking di-hydroxyethyl methacrylate, hydroxyethyl methacrylate and N-vinyl pyrrolidone with 2.5 mol% ethylene glycol dimethacrylate using the water soluble initiators – ammonium persulphate and sodium metabisulfite under a nitrogen atmosphere. The hydrogel was applied to the sensor by dip coating during polymerisation. Electrochemical measurements revealed that the response characteristics of sensors coated with this membrane are highly consistent. Scanning Electrochemical Microscopy (SECM) was used to spatially resolve glucose diffusion through the membrane by measuring the consequent hydrogen peroxide release and compared with an epoxy- polyurethane membrane.

A positive relationship between economic growth and entrepreneurship has been established as derived from the body of knowledge in the domain of entrepreneurship. In acknowledgement of this relationship, governments have embarked on schemes and policies that encourage entrepreneurship in their economic development policies. The individual entrepreneur is a key player in new entrepreneurial venture process. The entire society is responsible for shaping an environment within which a behaviour pattern that promotes or hinders entrepreneurship is developed. The study mainly focused on understanding the behavioural phenomenon which is termed entrepreneurial orientation (EO) of engineers within the South African context. The assumed EO of entrepreneurial engineers was expected to be higher than that of non-entrepreneurial engineers. Cronbach Alpha’s tests found the prestructured EO scale to be reliable. T-test results for mean difference confirmed that entrepreneurs have a higher EO on the overal EO construct as well as on the autonomy, proactiveness and risk taking dimemensions.Factor analysis results supported the view that the EO construct is unidimensional. Situational factors that shaped the social environment alluded to above were studied as a secondary objective. Chi-square tests did not confirm the expectation that entrepreneurial engineers would be exposed to situational factors that promote entrepreneurship than their non-entrepreneurial counter parts. Lack of entrepreneurial education and finance have been identified as the key factors that hamper entrepreneurship. Recommendations are included in this report.Copyright
Dissertation (MBA)--University of Pretoria, 2011.
Gordon Institute of Business Science (GIBS)
unrestricted

This study outlines the analysis of a post trade curriculum development system called Dacum. The term Dacum is an acronym for Developing A Curriculum. The system is generally considered to be a standard approach to competency based curriculum development and is used to plan the technical and vocational programmes for technician engineers. The analysis of the work roles for technician engineers is to show the range of activities they are engaged with in industries. Data for the study was collected through a survey conducted on behalf of New Zealand Engineering Industry Training Board. The generation of Dacum - charts and subsequent task analysis identifies the skills and beliefs required by technician engineers to perform successfully on a job and shows the relevance of the polytechnic studies as applied to their work. This also serves as a guideline to review curriculum design and training programmes for technician engineers that will render more effective practical application in their occupational roles.

Les interactions protéine-protéine (IPPs) médient la signalisation cellulaire. Leur ingénierie peut fournir des informations et conduire au développement de molécules thérapeutiques. Les domaines PDZ sont des médiateurs importants de IPPs. Elles lient les 4--10 résidus C-terminaux de protéines cibles. Elles lient aussi les peptides correspondants, qui peuvent servir de systèmes modèles ou d'inhibiteurs. Nous avons développé deux approches computationnelles et les avons appliquées au domaine PDZ de la protéine Tiam1, un facteur d'échange pour la protéine Rac, impliqué dans la protrusion neuronale. Sa cible est la protéine Syndecan1. Des affinités expérimentales sont connues pour le peptide C-terminal, noté Sdc1, et plusieurs mutants; elles ont servi pour tester les calculs. Nous avons d'abord développé une méthode de dessin computationnel haut débit. Une simulation Monte Carlo est faite où les chaines latérales de la protéine et du peptide peuvent changer de conformères et certaines positions peuvent muter. Le solvant est implicite. Le paysage énergétique est aplati par la méthode adaptative de Wang-Landau, de sorte qu'un vaste ensemble de variantes est échantillonné. Effectuant des simulations distinctes du complexe et du peptide seul nous avons obtenu les énergies libres relatives d'association de 75,000 variantes en heure CPU sur une machine de bureau. Les valeurs sont compatibles avec les quelques données expérimentales disponibles. Ensuite, nous avons développé une approche beaucoup plus détaillée et réaliste. Soluté et solvant sont décrits par un champ de force atomique, qui représente explicitement la polarisation électronique: le champ de force Drude de Charmm. La polarisabilité peut être importante car les résidus de l'interface PDZ:peptide passent, lors de l'association, d'un environnement riche en solvant à un autre pauvre en solvant. Nous avons fait des simulations alchimiques d'énergie libre pour comparer quatre variantes du peptide qui diffèrent par une ou deux chaines latérales ioniques. Les résultats sont en bon accord avec l'expérience. Les champs de force additifs Charmm et Amber, qui représentent la polarisabilité implicitement, donnent un moins bon accord. Ces calculs sont le premier exemple de simulations alchimiques d'énergies libre d'association relatives protéine: ligand avec un champ de force polarisable. Enfin, pour une modélisation future de peptides phosphorylés, nous avons étendu le champ de force Drude pour inclure le méthyl phosphate et la phospho tyrosine. Il en résulte un excellent accord avec les affinités expérimentales phosphate: magnésium
Protein-protein interactions (PPIs) regulate complex signaling networks in eukaryotic cells. Many binding events between several protein domains transfer information through communication pathways. Disrupting or altering the equilibrium between PPIs plays an important role inseveral diseases and the inibition of targeted PPIs is a recognized strategy for computational drug design. In the present thesis we focused on PDZ domains, which are among the most widespread signaling domains. PDZs recognize the 4-10 C-terminal amino acids of their target proteins as well as the corresponding peptides in isolation. We studied PDZ:peptide binding for the Tiam1 protein, which is a Rac GTP exchange factor involved in neuronal protrusion and axon guidance. Tiam1 activity modulates signaling for cell proliferation and migration, whose dysregulation increases growth of metastatic cancers. Its natural binder peptide is Syndecan1 (Sdc1), composed of 8 amino acids. Its last 5 Cter residues drive interactions in the binding pocket. Experimental affinities for several mutants of Sdc1 and in the protein domain constitute a complete dataset to study many ionic interactions with molecular simulations. These calculations are still challenging, despite the dramatic improvement of biomolecular modelling in the 1990's and 2000's. Upon binding, residues are transferred from a solvent-exposed environment to a solvent-poor one. This is expected to change the electron distribution within residues and nearby solvent molecules. Comparing ligands that differ by one or more ionic side-chain mutations, more sophisticated force fields where electronic polarizability is treated explicitly may be required. We developed and tested both Computational Protein Design (CPD) models and more precise free energy calculation methods based on polarizable molecular dynamics. We developed a general, high-througtput CPD protocol to optimize protein:peptide binding. The model has been implemented in on our in-house CPD package Proteus ( Simonson et al, 2014) and has been tested computing relative binding affinities for many variants of the Tiam1:Sdc1 complex. Monte Carlo sampling of equilibrium distributions of protein sequences is performed using an adaptive bias potential which flattens the energy landscape in sequence space and allows to estimate binding affinities for thousands of protein variants in limited CPU time (~1hour). We also improved our CPD implicit solvent model, implementing a more realistic description of the solute-solvent dielectric boundary. The new method, called Fluctuating Dielectric Boundary (FDB) showed a systematic improvement in the prediction of acid:base constants of several proteins. Promising results were also obtained for the complete sequence redesign of three PDZ domains. In the second part of this work we studied Tiam1:peptide affinities with more sophisticated models, based on free energy simulations with the Drude Polarizable Force field (DrudeFF). We first computed relative binding free energies for charge mutations in the Tiam1:Sdc1 complex, obtaining a clear improvement respect to equivalent calculations performed using two additive force fields. We applied the well-enstablished Dual Topology Approach: to our knowledge, this was the first example of such a calculation for a protein:peptide complex with uses the DrudeFF. Then we went on, developing the Drude polarizable models for methyl phosphate (MP) and phospho tyrosine (pTyr). We were interested in the change in binding affinity associated with phosphorylation of a Tyrosine residue of Sdc1, but Drude pTyr parameters were not yet developed. We tested our new phosphate parameters studying standard binding free energies between MP and magnesium (Mg2+) in water solution. Results showed a good agreement with experiment, improving previous calculations performed using additive force field

William Fairbairn was a major engineer, active in many branches of mid-nineteenth-century engineering. From an apprenticeship as a colliery millwright, he went on to establish a world-class engineering business in Manchester, playing a major role in mill-building, experimental engineering, bridge construction and iron shipbuilding. Despite his importance there is no modern study which brings together the many diverse areas of his work, and the company he founded, nor does any study give adequate emphasis to the discrete and different chronological phases of Fairbairn’s career. The thesis aims to provide a composite study of Fairbairn’s life and work, answering three main questions. First, how is the rise of Fairbairn and his Company to positions of leadership and influence within the engineering industry accounted for? Secondly, in what respects were both Fairbairn and the Company he founded important and influential, and how was that influence spread? Thirdly what caused one of the most successful engineering companies, with a global reputation, to cease to trade within a year of its founder’s death? The opportunity is taken to re-assess the range and significance of Fairbairn’s contributions to nineteenth-century engineering. This thesis argues that Fairbairn was more an ‘innovator’ and optimiser than an inventor. Five areas stand out as particularly influential amongst the multiplicity of his achievements, as a builder of mills with their prime-movers, as the foremost experimental engineer of his time outside the universities, as a leading iron shipbuilder during iron shipbuilding’s most critical decade - 1835-1844, as a builder of tubular structures – bridges and cranes - during a two-decade window, and in connection with steam boilers. The thesis shows education to have been a lifelong commitment of Fairbairn, with his Ancoats works the successor to Maudslay’s ‘nursery’. It also poins to him as a transitional figure in a time of rapid change. However his career was unpredictable. No one model of technological innovation fits all Fairbairn’s work, and his investigations and experiments challenge the imposition of any uniform theory of technological change. Set-backs are identified, as well as Fairbairn’s successes. Reasons are argued for the dissolution of his partnership with Lillie, the closure of his shipyard, and his failure to obtain various bridge commissions. The ultimate demise of a great engineering firm, within a year of its founder’s death, is traced primarily to the matter of succession following Fairbairn’s retirement from a managerial role, and the contrasting approach of his successors.

Augmenter la part de marché du bois dans la construction non résidentielle est un objectif important dans les pays où les produits forestiers et de bois d'ingénierie jouent un rôle fondamental. Afin de faciliter la production de structures en bois innovantes, il est nécessaire de mettre sur pied des procédures de réingénierie en termes d’analyse de marché et d’amélioration de la productivité. L'objectif principal de cette thèse est de faciliter la production de bois d'ingénierie (produits en lamellé-collé) destiné à être utilisé dans des structures en bois innovantes telles que les résilles en bois. Pour atteindre ce but, trois objectifs spécifiques sont définis. Le premier objectif est de déterminer les phases de production et les opportunités de marché pour la production de résilles en bois. À cet égard, une revue de la littérature académique et de la littérature grise a été réalisée, et vingt échantillons ont été identifiés et analysés à l'aide de diagrammes de processus et de catégorisations. Les résultats ont montré qu’une structure en résille de bois est utilisée dans l'industrie de la construction en Europe et qu'elle est moins connue en Amérique du Nord, ce qui offre une opportunité de marché pour sa production et sa construction. La catégorisation des échantillons étudiés dans les petites, moyennes et grandes structures et l'identification des acteurs pour chaque catégorie fournissent une vue d'ensemble pour les entreprises qui envisagent la production de cette structure. Le deuxième objectif de cette thèse est de fournir un modèle de simulation pour la production de bois lamellé-collé dans de petites usines et le processus d'application de techniques Lean pour apporter des améliorations. À cet égard, le système de production d’une entreprise québécoise a été analysé et un modèle de simulation créé. Afin d'éliminer chaque source de gaspillage, un outil Lean a été suggéré en fonction de la réalité du système à l’étude. Les résultats ont montré une amélioration notable du temps d’attente et de cycle suite à l’utilisation de techniques issues du Lean. Ils ont également contribué à souligner qu’une élimination du gaspillage limitée à 50% pouvait améliorer la considérablement la productivité pour les petites entreprises et s’avérer un premier pas important dans l’implantation du Lean. Le troisième objectif est de fournir un outil de planification et d'ordonnancement de la production dans un contexte de production multi-projets d’ingénierie sur commande (Engineer-to-Order) de bois lamellé-collé. À cet égard, des modèles d'optimisation ont été créés. Le premier modèle (modèle 1) concerne la minimisation du coût de production total, tandis que le modèle 2 vise la minimisation de la durée totale des projets. Le modèle 3 cherche plutôt à réduire le temps de mise en route sur la presse, le poste goulot du système de production considéré. Le modèle 4 intègre les trois objectifs de réduction des coûts, de durée et de temps de mise en route. Deux scénarios d’ajout de projets de grande et de moyenne envergure ont été conçus et testés. Le test des scénarios démontre qu'il y a une capacité suffisante pour l’ajout d’un projet de grande envergure ou de neuf projets de taille moyenne sans recourir à la sous-traitance. L'ajout d'un projet de grande envergure est plus sensible à la période d'insertion, pouvant exiger du temps supplémentaire selon la date de début du projet. Les travaux de cette thèse permettent donc de fournir des outils d'aide à la décision pour les entreprises œuvrant dans un milieu d'ingénierie sur commande afin d'améliorer leur productivité et la standardisation de leurs processus.
Increasing the share of wood in non-residential construction is an important goal in countries with major forest and engineered wood products. In order to facilitate the production of innovative timber structures, procedures should be re-engineered in terms of market analysis and productivity improvement. The main objective of this thesis is to facilitate the production of engineered wood to be used in innovative wood structures such as timber gridshell. To achieve this goal, three specific objectives are defined. The first objective is to determine production phases and market opportunities for the production of timber gridshell. In this regard, a review of the academic and grey literature was conducted, and twenty samples were identified and analysed by making process charts and categorisations. The results showed that gridshell is used in the construction industry in Europe and is less recognised in North America, which provides a market opportunity for its production and construction. The categorisation of studied samples in small, medium and large structures provides an overview for the companies who consider the production of this structure. The second objective of this thesis is to provide a simulation model for the production of glued laminated timber in small factories and the process of applying lean techniques to make improvements. In this regard, the production system of a Small and medium-sized enterprise (SME) was analysed, and a simulation model was created. In order to eliminate each source of waste, a lean tool was suggested according to the reality of the system under investigation. The lean methods were applied in the simulation model to analyse the potential improvements. Results showed a noticeable improvement in waiting and cycle time. It also showed that applying even 50% elimination of the wastes is also a considerable solution to improve productivity as a beginning step for SMEs. The third objective is to provide a production planning and scheduling tool in the context of multi-project engineer-to-order production of glued laminated timber. In this regard, optimisation models were created. The first model (model 1) concerns the minimisation of total production cost while model 2 aims to minimise projects’ makespan. Model 3 introduces the set-up time reduction and model 4 integrates the three objectives of minimising cost, makespan and set-up time. Two scenarios of adding complex and medium projects were designed and tested. Testing the scenarios showed that there is enough capacity for adding one complex project or nine medium projects without the need to outsource. Adding a complex project is more sensitive to the insertion period and beginning the project in different weeks leads to different results in terms of the overtime requirement. As a result, the work of this thesis provides decision support tools for engineer-to-order environments which could help SMEs to improve their productivity and standardisation.
Résumé en espagnol

Der Vortrag zeigt die Einsatzmöglichkeiten und den Nutzen von BMX auf. Zudem wird die Vorgehensweise bei BMX-Analysen erläutert. Die Neuerungen in der Pro/ENGINEER-Version Wildfire 5 werden vorgestellt. Anhand von 3 Live-Demonstrationen wird die Anwendung von BMX gezeigt: - Flaschen-Volumen untersuchen - Messerkopf dynamisch auswuchten - Sichtfelduntersuchung

This is a 15 credits thesis in mechanical engineering performed at the PLM Solutions group at the Rocktec division within Atlas Copco Rock Drills AB, Örebro, during spring 2012. When designers working with 3D CAD modeling uses different work methods in Pro/ENGINEER (Pro/E) it sometimes results in problems. It is also a problem when designers do not follow the specific work methods defined by Atlas Copco.   The purpose of this thesis was to identify the most common problems with 3D models at Atlas Copco Rock Drills AB (RDE) Örebro related to work methods, for example why models crash, why they cannot be checked in to Pro/Intralink or why there are unstable references. The objective was to present a work method to avoid one or two of the most severe problems identified at RDE Örebro.   To achieve the objective I started with going through the CAD support call data base, to find out in what areas the organization needed help from the CAD support. The result shows that the engineers request most support in how to use both the modeling and the drawing modules in Pro/E. I also came up with a suggestion for redesign of the CAD support call data base system, that could reduce the time needed for this kind of analysis from days to minutes.   Thereafter a number of engineers, all with high skills in Pro/E, were selected for personal interviews. The topic was to identify any lack in defined work methods in Pro/E causing problems that are taking long time to correct. The result shows that the biggest issue for the users is references. I also performed a benchmarking with two other companies within the Atlas Copco Group looking at their CAD guidelines regarding the issues found during the interviews.   Thirdly, one assembly each from six different departments were selected and sent to PTC for an in depth analysis with their software tool Expert Model Analysis. The goal was to find any systematic issues regarding work methods in Pro/E. The analysis confirmed what the engineers earlier had brought up as the main issues, namely, references, mass/weight handling and structure in the model tree.
Detta är en 15 hp examensarbete i maskinteknik som utförs på PLM Solutions Group på Rocktec divisionen inom Atlas Copco Rock Drills AB i Örebro, under våren 2012.När konstruktörerna arbetar med 3D CAD modellering använder de olika arbetsmetoder i Pro/ENGINEER (Pro/E) vilket ibland leder till problem. Det är också ett problem när konstruktörerna inte följer de arbetsmetoder som definierats av Atlas Copco.Syftet med detta examensarbete var att identifiera de vanligaste problemen med 3D-modeller på Atlas Copco Rock Drills AB (RDE) i Örebro relaterat till arbetsmetoder, till exempel varför modellerna kraschar, varför de inte kan checkas in i Pro/Intralink eller varför det finns instabila referenser. Målet var att presentera en arbetsmetod för att undvika ett eller två av de mest allvarliga problemen identifierade vid RDE Örebro. För att uppnå målet började jag med att gå igenom CAD-supportens samtalsdatabas, för att ta reda på inom vilka områden användarna behövde hjälp från CAD-support. Resultatet visar att konstruktörerna behöver mest hjälp med hur man använder både modellerings- och ritningsmodulerna i Pro/E. Jag tog också fram ett förslag till hur CAD-supportens samtalsdatabas kan göras om, som skulle kunna minska tiden som behövs för denna typ av analys från dagar till minuter. Därefter valdes ett antal ingenjörer ut, alla med hög kompetens inom Pro/E, för personliga intervjuer. Syftet var att identifiera eventuella brist i befintliga arbetsmetoder i Pro/E, vilka orsakar problem som tar lång tid att rätta till. Resultatet visar att det största problemet för användarna är referenser. Jag utförde också en benchmarking med två andra bolag inom Atlas Copco-gruppen genom att jämföra deras CAD rekommendationer kring de problem som kom fram under de tidigare intervjuerna. Som tredje del i examensarbetet valdes en CAD-modell från vardera sex olika avdelningar och skickades till PTC för en fördjupad analys med deras program Expert Model Analysis (XMA). Målet var att hitta systematiska problem gällande arbetsmetoder i Pro/E. XMA-analysen bekräftade vad ingenjörerna tidigare hade fört fram som de viktigaste frågorna, nämligen referenser, massa/vikt hantering och struktur i modellen trädet.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (leaves 65-66).
by Jennifer Joyce Mulligan.
S.M.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2018
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 159-195).
The microbes that inhabit the human body are integral to human health and disease: from inflammatory bowel disease to allergy, metabolic syndrome to autism. Due to its high connectivity with human physiology, manipulation of the microbiota has therapeutic potential in a vast array of diseases. However, techniques for targeted modification of microbial communities are currently lacking. In this thesis, I present several technologies that can be applied to engineer and better understand the microbiota. First, we present a subtractive strategy for microbiota manipulation using CRIPSR-Cas engineered bacteriophage that can selectively remove target strains from a community based on the presence of target DNA sequences. Next, we describe an additive strategy whereby commensal Bacteroides spp. are genetically modified to perform novel functions within the murine microbiota. We developed a suite of genetic parts to facilitate organism design and engineering. These tools were then expanded to engineer outer membrane vesicles derived from Bacteroides as immunomodulatory agents. Finally, we leveraged the natural sensing abilities of bacteria to create cellular biosensors for biomarkers of gastrointestinal disease. Heme biosensors were paired with readout electronics to generate an ingestible medical device for in situ detection of gastrointestinal bleeding. The technologies described herein contribute to the progression of microbiome engineering towards clinical applications and the advancement of our understanding of how our smallest friends impact our health.
by Mark Mimee.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Biology

Abstract While most of the in vitro cultures are carried out on bi-dimensional (2D) substrates, most of the in vivo extracellular matrices are threedimensional (3D). Consequently cells behave differently on 2D substrates as a way to self-adaptation to a non-physiological environment. This fact has encouraged the development of more relevant culture conditions seeking to provide more representative models for biomedicine (e.g. cancer, drug discovery and tissue engineering) and further insights into any dimension-dependent biological mechanism. Different 3D culture systems have been established though their variability and complexity hinder their standardisation in common cell culture procedures. So, this thesis deals with the dimensionality issue in cell/material interactions and introduces sandwich-like microenvironments as a versatile tool to study cell behaviour. Cells cultured within this system use both dorsal and ventral receptors to adhere and spread, undergoing important changes with respect to the 2D cultures and approaching to 3D conditions. Stimulation of dorsal receptors has been previously addressed by overlaying a protein gel on cells already attached on a 2D surface. Here we propose a sandwich-like system that consists of two 2D surfaces so that wider spectra of conditions can be investigated by changing the nature of the substrate (material, topography…) and the protein coatings of both ventral and dorsal sides. Since sandwich culture provides an altered cellular adhesion compared to the traditional 2D substrates by the excitation of the dorsal receptors, changes in the intracellular signalling are expected, which might alter important processes such as proliferation, morphology, migration and differentiation. Hence this thesis evaluates the effect of different sandwich culture parameters in cell behaviour. First, cell fate upon adhesion was evaluated in terms of morphology, proliferation and adhesion. Different conditions were studied such as materials with different properties or protein coatings (dorsal and ventral substrates), as well as the effect of sandwiching cells just after seeding or after been allowed to adhere to the ventral substrate. Interesting results were obtained such as the relationship between the ability of cells to reorganise the ECM with cell morphology, proliferation and adhesion, similarly as observed in 3D hydrogels (degradable vs nondegradable systems). Then, cell migration within sandwich culture was studied by live imaging of a wound healing assay. Results revealed the key effect of both ventral and dorsal substrates in determining the migration rate as well as the migration mode used by cells. Moreover cells within the sandwich culture migrating in the wound healing assay adopted an elongated cell morphology that resembled cells migrating in other 3D systems. Beyond differences in cell morphology and migration, dorsal stimulation promoted cell remodelling of the extra-cellular matrix (ECM) over simple ventral receptor activation in traditional 2D cultures. Finally the effect of sandwich culture on cell differentiation was evaluated. First we showed an increase in C2C12 myogenic differentiation when cultured within the sandwich system. This enhancement was shown to be dorsal stimulation dependent and related to an alteration of the signalling pathway and the growth factor release. To determine if sandwich culture leads only to myogenic differentiation or whether it allows differentiation to other lineages, 4 different human mesenchymal stem cells (hMSCs) lines were cultured under the same conditions. Results showed the same sandwich environment triggered different cell differentiation. This points out the importance of the microenvironment cell niche in vivo, which highly influence cell fate, and thus the need of mimicking it properly in vitro. Overall, sandwich-like microenvironments switch cell behaviour towards 3D-like patterns, demonstrating the importance of this versatile, simple and robust approach to mimic cell microenvironments in vivo.
Ballester Beltrán, J. (2014). Sandwich-like systems to engineer the cellular microenvironment [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48166
TESIS

This thesis ventures with the extracellular matrix protein (ECM) fibronectin (FN) as an interface protein in the interaction between cells and materials to design microenvironment for future use in tissue engineering. It is studied the FN adsorption and conformations, cell behaviour to different FN conformation, cell adhesion, reorganisation and remodelling of FN at the material interface, the role of growth factors (GF) and their interactions with components of the extracellular matrix (ECM), the immunology cell response, and the stem cell fate influenced by the extrinsic signals coming from the engineered microenvironments using ECM's proteins. To investigate the FN response, in terms of adsorbed amount and conformation to different chemical properties of the material, model surfaces were used. Self assembled monolayers (SAM) with different percentages of two different chemical groups were used: CH3 and OH. FN adsorption, initial cell adhesion and signalling (focal adhesions, integrin expression and phosphorylation of FAK) is related with the reorganisation and secretion of FN and matrix degradation. It is shown that matrix degradation at the cell material interface depends on surface chemistry in metalloproteinase-dependent way. A direct relationship between FN activity at the cell-material interface and metalloproteinase 9 (MMP9) expression was found, being the product of a sequence of events that include integrin expression, focal adhesion formation, matrix reorganisation and focal adhesion kinase (FAK) phosphorylation. Two different materials with subtle variations in their chemical composition were employed as a drastically different FN conformation: from a globular conformation on PMA (poly (methyl acrylate)) to the formation of a well-interconnected FN network (similar to the FN physiological fibrillar network) triggered by PEA (poly (ethyl acrylate)). The formation of focal adhesions (vinculin), FAK expression and phosphorylation, specific integrin binding, protein and gene expression for ¿5 and ¿v was studied, seeking to correlate cell adhesion with matrix degradation. It is demonstrated that the material-driven FN fibrillogenesis on PEA triggers proteolytic activity: MMP activity is higher as a compensatory mechanism to the inability of cells to reorganise this FN network. Looking into the role of protein-material interactions and stem cell fate, and with the knowledge on PEA, we engineer different synergistic microenvironments to direct cell and stem cell fate. FN has a growth factor (GF) binding domain on its molecule (FNIII12-14) and has been demonstrated to produce a synergistic response when occurs at the same time the recognition of the cell binding domain (FNIII9-10). It is demonstrated that this domain is available on the FN coated PEA, and exploiting these interactions between PEA, FN and GF, it is developed a microenvironment to control cell behaviour and tissue repair. It is studied the BMP2 binding and presentation, the effect of BMP2 presentation on MSC proliferation and differentiation. These systems allow not only enhanced activity of GF compared to soluble administration, but also reduce GF doses, improving safety and cost effectiveness. Finally, the immunological reaction of the microenvironment developed is studied using dendritic cells, beside the conformational structure of ECM protein importance in DC integrin-based activation it is studied, helping to establish the field of adhesion-based modulation of DC as a general mechanism that has previously not been defined. The microenvironment didn't induce any maturation in DC, while different FN conformation shows differences in DC morphology and citokine level production (IL-10 and IL-12).
En esta tesis se estudia la interacción de una proteina de la matriz extracelular, fibronectina (FN) como interfase en la interacción entre células y materiales, para diseñar microambientes con el propósito de ser usados en el futuro en ingeniería tisular. Se estudia la adsorción y conformación de FN y la relación con el diferente comportamiento celular: la adhesión celular, la reorganización y remodelado de la FN en la interfase célula-material, el papel que juegan los factores de crecimiento y sus interacciones con los componentes de la matriz extracelular, la respuesta immunológica y el destino celular de células madre influenciadas por las señales extrínsecas provenientes de microambientes elaborados a partir de proteínas de la matriz extracelular. Con el objetivo de investigar la respuesta a la FN en términos de conformación y cantidad absorbida a diferentes propiedades químicas del material, se usaron materiales modelo: monocapas autoensambladas (self-assembled monolayers, SAM). Las químicas estudiadas fueron CH3 and OH. La adsorption de FN, adhesion y señalización (adhesiones focales, expresión de interinas y fosforilación de quinasas de adhesiones focales (FAK)) se estudiaron en relación a la reorganización y secreción de FN y degradación de la matriz extracelular. Se demuestra que la degradación de la matriz extracelular en la interfase célula-material depende de la química de la superficie, a través de las metaloproteinasas. Se ha descubierto una relación directa entre la actividad de la FN que se encuentra en el material y la expresión de metaloproteinasa 9 (MMP9), a través de la expresión de integrinas, formación de adhesiones focales, reorganización de la matriz extracelular y fosforilación de FAK En el siguiente capítulo se emplean materiales poliméricos con una sutil diferencia en la composición química, provocando una diferencia drástica en la conformación de la FN: se pasa de una conformación globular en PMA (polimetil acrilato) a una conformación en forma de red interconectada en PEA (polietil acrilato). Con el propósito de relacionar la adhesión celular con la degradación de la matriz extracelular, se estudia la formación de adhesiones focales (vinculina), la expresión y fosforilación de FAK, la unión específica de integrinas y la expresión de las integrinas ¿5 and ¿v. Se demuestra que la formación de una red de FN sobre PEA induce la actividad proteolítica: la actividad de las MMPs es mayor, actuando como mecanismo compensatorio a la incapacidad de reorganización de la red de FN. Haciendo uso de la conformación de la FN sobre PEA, se estudiaron las interacciones entre la proteína-material y el destino celular de células madres. La FN posee un dominio de unión de factores de crecimiento (FNIII12-14) y se ha demostrado que se produce una respuesta sinérgica cuando el reconocimiento ocurre junto con el dominio de unión celular (FNIII9-10). En esta tesis se demuestra que el dominio de unión de factores de crecimiento está disponible en la conformación que adquiere sobre PEA y se diseñan microambientes para controlar el comportamiento celular y regeneración de tejido. Se estudia la unión y presentación de BMP2 y su efecto en la diferenciación de células madre mesenquimales. Los microambientes desarrollados, ademas de mejorar la actividad de los factores de crecimiento comparado con la administración soluble, también reduce la cantidad de factores de crecimiento que se tendría que administrar, mejorando la seguridad y efectividad. Finalmente se estudió la reacción inmunológica a los microambientes desarrollados usando células dendríticas, estudiando además la influencia de la estructura de la conformación de las proteínas en la activación de las células dendríticas a través de las integrinas. Los microambientes no indujeron ninguna maduración de células dendríticas, mientras que la conformación de la FN muestra control
En aquesta tesi s'estudia la interacció entre una proteïna de la matriu extracel.lular, fibronectina (FN) com interfase en la interaccio entre cèl·lules i materials, per a dissenyar microambients amb el propòsit d'utilitzar-se al futur en enginyeria tissular. S'estudia l'adsorció i conformació de la FN i la relació amb el diferent comportament cel·lular: l'adhesió cel·lular, la reorganització i remodelat de la FN a la interfase cèl·lula-material, el paper que juguen els factors de creixement i les seus interaccions amb els components de la matriu extracel·lular, la resposta immunològica i el destí cel·lular de cèl·lules mare influenciades pels senyals extrínseques provinents de microambients elaborats a partir de proteïnes de la matriu extracel·lular. Amb l'objectiu d'investigar la respostar a la FN en termes de conformació i quantitat absorbida a diferents propietats químiques del material, s'utilitzaren materials model: monocapes autoacoblades (self-assembled monolayers, SAM). Les químiques estudiades van ser CH3 and OH. L'absorció de FN, adhesió i senyalització (adhesions focals, expressió d'integrines i fosforilació de quinases d'adhesions focals (FAK)) es van estudiar en relació a al reorganització i secreció de la FN i degradació de la matriu extracel·lular. Es demostra que la degradació de la matriu extracelular en la interfase cèl·lula-material depèn de la química de la superficie, a través de les metal·loproteïnases. S'ha descobert una relació directa entra l'activitat de la FN que es troba en el material i l'expressió de metaloproteinasa 9, a través de l'expressió d'integrines, formació d'adhesions focals, reorganització de la matriu extracel·lular i fosforilació de FAK. Al següent capítol es fan servir materials polimèrics amb una subtil diferència en la composició química, provocant una diferència dràstica en la conformació de la FN: es passa d'una conformació globular en PMA (polimetil acrilat) a una conformació en forma de xarxa interconnectada en PEA (polietil acrilat). Amb el propòsit de relacionar l'adhesió cel·lular amb la degradació de la matriu extracel·lular, s'estudia la formació d'adhesions focals (vinculina), l'expressió i fosforilació de FAK, la unió específica d'integrines i l'expressió de les integrines ¿5 and ¿v. Es demostra que la formació d'una xarxa de FN sobre PEA indueix l'activitat proteolítica: l'activitat de les MMPs és més gran, actuant com a mecanisme compensatori a la incapacitat de reorganització de la xarxa de FN. Fent ús de la conformació de la FN sobre PEA, es van estudiar les interaccions entre la proteïna-material i el destí cel·lular de cèl·lules mares. La FN posseeix un domini d'unió de factors de creixement (FNIII12-14) i s'ha demostrat que es produeix una resposta sinèrgica quan el reconeixement ocurreix juntament amb el domini d'unió cel·lular (FNIII9- 10). En aquesta tesi es demostra que el domini d'unió de factors de creixement està disponible a la conformació que adquireix sobre PEA i es dissenyen microambients per controlar el comportament cel·lular i regeneració de teixit. S'estudia la unió i presentació de BMP2 i el seu efecte en la diferenciació de cèl·lules mare mesenquimals. Els microambientes desenvolupats, a més de millorar l'activitat dels factors de creixement comparat amb l'administració soluble, també redueix la quantitat de factors de creixement que s'hauria d'administrar, millorant la seguretat i efectivitat. Finalment es va estudiar la reacció immunològica als microambients desenvolupats usant cèl·lules dendrítiques, estudiant a més la influència de l'estructura de la conformació de les proteïnes en l'activació de les cèl·lules dendrítiques a través de les integrines. Els microambients no van induir cap maduració de cèl·lules dendrítiques, mentre que la conformació de la FN mostra controlar la morfologia de les cèl·lules dendrítiques i
Llopis Hernández, V. (2017). Material-driven fibronectin fibrillogenesis to engineer cell function [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90412
TESIS

Tendons are able to undergo repeated cyclic loading in vivo without permanent deformation or mechanical failure. However, diseased, traumatised and decellularised tendons gradually lose the ability to resist load and fail because of creep deformation. The molecular basis of the mechanical properties of tendon and how cells establish and maintain these properties is poorly understood. New knowledge in this area is required to develop novel medical strategies to improve tendon repair and regeneration. Recent advances in tissue bioengineering have led to the formation of fibrin-based tendon-like tissue (‘tendon constructs’) that display the mechanical properties and ultrastructure of embryonic tendon. This thesis presents the characterisation of the tendon constructs derived from primary fibroblasts to understand the relationship between the cells and matrix during tissue development, and to establish the standard of in vitro engineered tendons. These findings facilitated protocol development to engineer human tendon-like tissue derived from stem cells. Novel findings of constructs formed from differentiated human pluripotent stem cells in feeder and feeder-free systems are presented. Fibrin gels were seeded with human dermal fibroblasts (HDF), chick tendon fibroblasts (CTF), MAN5 (Manchester, embryonic stem) cells, human embryonic stem cells (HuES7) and induced pluripotent stem cells (iPS). The gels were cultured until isometric tendon-like constructs were formed (T0) or continued for four or ten days post-formation. The mechanical properties, histology and gene expression of the constructs were analysed and compared between the constructs seeded with the aforementioned cell types. Varying the initial cell number (tested in CTF-seeded fibrin and collagen based constructs) significantly affected the final cell count and the mechanical properties of the constructs differentially at T0 and T10. A non-linear relationship exists between the initial and final cell number, and, between the initial cell number and mechanical properties. However, the results showed that cell number impacted cell-matrix stabilisation as strength per se was strongly dependent on initial cell number. Collagen-based constructs showed a significantly lower stiffness compared with fibrin-based constructs at T0 and T10. The stem cells and primary cells reproducibly underwent morphogenesis to form a 3D tissue similar to embryonic tendon in vivo expressing ECM markers such as collagens type I and III. The tissue also exhibited the ultrastructural characteristics and biomechanical profile of immature tendons. RNA seq and qPCR results demonstrated the upregulation of tendon-specific genes. Tendon-like tissue generated from human stem cells and HDFs in vitro has the potential to replace functional tissue lost through disease and to advance the understanding of the molecular basis of human tenogenesis.

International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California
Flight test engineers, a unique group of individuals whose tasks are to test and evaluate aircraft in operational environments, are faced with the problem of supporting the complex instrumentation formats and higher data rates that are now appearing on airborne instrumentation platforms. The majority of off-the-shelf portable telemetry support equipment has not kept up with the demands of the modern-day Flight Test Engineer-Data Analyst.

Im Optimierungsprozess einer Konstruktion und zur Variantenbildung ist die Nutzung der Parametrik für den Konstrukteur zum Standard und unverzichtbar geworden. Auslegungen und speziell die Festlegung von Abmessungen werden im Maschinenbau über die Umstellung von Analysegleichungen oder durch iterative Analysen, wie bspw. die numerische Optimierung durchgeführt. Die Mechanismenlehre ist eines der wenigen Fachgebiete, in denen speziell für die Auslegung klassische Syntheseverfahren entwickelt wurden. Im Zeitalter vollparametrischer CAD-Systeme erscheinen diese Verfahren in einem neuen Licht. Einfache getriebetechnische Kenntnisse sind für die Lösung von Führungs- und Bewegungsaufgaben zwar erforderlich, sind in Lehrbüchern, VDI-Richtlinien, TGL-Blättern usw. aber auch gut nachzulesen. Anhand einiger Beispiele soll hier gezeigt werden, wie diese klassischen grafischen Konstruktionsvorschriften auf einfache Weise in das CAD-System Pro/Engineer Wildfire integriert werden können. Der Konstrukteur kann seine Auslegung dynamisch interaktiv variieren und sogar verschiedene Gütewerte seines Getriebes dabei beobachten. Durch diese assoziative Komponente wird eine mehrparametrige Optimierung realisierbar. Im Vortrag wird an Beispielen gezeigt, dass ein CAD-Konstrukteur diesem Vorschlag folgen und das Verfahren anwenden kann, um einen ersten Entwurf vorzulegen. Eine weitgehende Verwendung von Zusatzmodulen, wie zum Beispiel Pro/Mechanica oder Pro/Mechanism, würde erst bei zusätzlichen Untersuchungen der Konstruktion erforderlich.

Product proliferation as a result of meeting ever increasing customer demand preferences is well documented. In addition, customisation has been promoted as a source of competitive advantage. Despite these factors, most of the published research in operations and supply chain management has neglected the needs of the engineer-to-order (ETO) sector, where each product, or project, is designed for the needs of a specific customer. This thesis investigates definitions, models, concepts and strategies for the ETO supply chain structure. In particular, it ETO supply chains are researched within the specific context of the construction sector. The high levels of uncertainty associated with such supply chains presents an array of challenges for organisations in the sector. This thesis focuses on methods to identify and categorize uncertainty, and the types of flexibility that can be developed to mitigate such uncertainties. The importance of good 'pipeline management' is also highlighted, which is an area that is lacking in the construction management literature. Initially, the ETO supply chain is defined in relation to five other 'structures', which describe the flow and control mechanisms of products throughout different supply chains. A key defining characteristic is that the 'decoupling point' is located before the design stage. A structured literature review is then undertaken, which integrates construction supply chain research with wider ETO research. Construction and ETO bodies of knowledge have largely evolved in isolation, within different disciplines, academic communities and journals. This thesis integrates these bodies of knowledge. A critical realist stance is adopted in the thesis, and a range of research methods are utilised within a multiple case design. The empirical research is structured in two phases. Firstly, case studies are undertaken in the construction industry. Three units of analysis are specified in the case research: network co-ordinators, projects and supplier pipelines. In total, the case investigation involves two 'network co-ordinators', five projects and twelve 'supplier pipelines', across two ETO construction systems. Secondly, six evaluation interviews are undertaken, using participants from a range of ETO construction industries. Flexibility is identified as an important strategic capability for ETO supply chains, and a conceptual model for supply chain flexibility is developed and investigated. A four step route map, which brings together different elements of the thesis, is a key output from the research, and provides a practical guide for practitioners to follow when considering flexibility strategies. The overall findings suggest that by becoming more flexible ETO construction supply chains can mitigate some of the uncertainties experienced, but this requires due consideration of supply chain uncertainties, pipeline management, and the correct types of flexibilities vis-a-vis collaborative arrangements. A contribution is made to the fields of uncertainty and flexibility within the context of ETO construction.

Sharing Knowledge is considered an important part of managing new product development (NPD) research on the process of NPD and Knowledge Management methods have influenced industry in various ways. For example the management of the NPD process, the use of tools, techniques and the organisation of teams, and the integration of the marketing and manufacturing have resulted in considerable progress within NPD process. Prior studies on the NPD problems have delivered various models of the NPD process and a variety of supporting methods, tools and techniques in a generic context. A more realistic scenario however, is to consider the needs of firms that develop products on a Make-to-Order (MTO) or Engineer-to-Order (ETO) basis. The research methodology adopted was based on extracting a preliminary ETO model supported by variety of Knowledge Management methods, tools and techniques from the review of literature. To examine the applicability of these models and methods and also the influential factors on the NPD process a survey by questionnaire and structured interviews in UK industrial companies was carried out. Findings were bound together to provide a generic model of the ETO process and a framework for the knowledge sharing on the specific needs of ETO manufacturing companies. IDEFO technique was used to develop the preliminary and the generic models. The objective of this research is to construct a structured and practical framework for supporting the opportunity for knowledge sharing within one-off projects. The knowledge sharing framework referred to as 'Sharing-ETO-Knowledge' (SETOK) was translated into a computer program using the "MS Visio' enterprise modelling systems. It was examined by applying the system program to the data of the two cases that had been obtained at the case study stage. The framework has been fruitful in the provision of a guideline for the implementation of the knowledge sharing in various NPD-ETO projects. The SETOK framework may be viewed as a practical, robust generic tool to assess the process performance of ETO manufacturing projects. The outcome of this study would help ETO manufacturing companies in their knowledge sharing and decision making processes with regards to NPD-ETO manufacturing projects.

Epithelial crypts isolated from normal colon mucosa have been cultured in vitro in the form of organoids. These organoids have been shown to have regenerative potential when implanted in mouse models of denuded colon mucosa. However, a major limitation in the translation of these studies to a clinical setting is the use of Matrigel, which is clinically unsuitable due to its undefined composition and potential for tumourigenicity. Additionally, enclosed organoids do not fully reproduce the structure and function of native tissue, and do not lead to full integration into the host. Therefore, the overall aim of this thesis was to investigate different scaffolds for their ability to support growth of primary colon epithelial cells in order to form an open monolayer structure that resembles native epithelium. It was anticipated that in vitro culture of primary colon cells would be more efficient with isolated stem cells than with an entire heterogeneous epithelial cell population. Therefore, the side population technique was explored using established cell lines as a method of isolating a population enriched in stem cells, based on their ability to efflux the Hoechst 33342 dye. This was found to be irreproducible and unreliable so was not pursued further. Various scaffolds were manufactured, characterised and seeded with colon epithelial cell lines to investigate how their morphological and biochemical characteristics influenced cell proliferation and differentiation. Electrospun nanofibre and microfibre scaffolds made from the synthetic material PET, and the natural polymer gelatin were fabricated. All electrospun scaffolds supported proliferation, and cells on gelatin nanofibre scaffolds differentiated to form tight junctions that are typical of epithelial cells, while also expressing increased levels of the stem cell marker ABCG2. Thereby, gelatin nanofibres demonstrated the ability to support appropriate cell differentiation while maintaining a pool of stem cells. Gelatin in the form of hydrogel scaffolds was also investigated for its ability to support cell proliferation and influence cell differentiation. Moreover, a novel method of rapidly 3D printing scaffolds using unmodified gelatin was presented. Both planar and 3D gelatin scaffolds were able to support proliferation and tight junction formation in Caco2 cells. Thus, it was concluded that gelatin hydrogels are a suitable substrate for proliferation and differentiation of colon carcinoma cell lines, and that the addition of the printed topography did not have any negative effects on cell growth and behaviour. Epithelial crypts were isolated from human colon mucosa and expanded in vitro in the form of organoids, as previously published. It was found that the precise nature and source of organoid media components are critical for successful primary cell culture. A method in which the Wnt signalling cascade is indirectly activated by GSK3β inhibition was found to be partially successful for growing organoids and may be a potential alternative culture method. Primary organoid cells were seeded onto gelatin nanofibre and hydrogel scaffolds, however the cells did not proliferate in these preliminary experiments. Overall, it was concluded that although the gelatin scaffolds demonstrated promising results with colon carcinoma cell lines, more research would be required in order to produce scaffolds that can support growth of primary colon epithelial cells.

This thesis includes two parts. The first part reviews the history and fundamentals of surface science and tribology. The second part presents the major research outcomes and contributions. This research explores the aspects of friction, wear, and surface modification for tribological augmentation of surfaces. An effort has been made to study these aspects through gaining insights by fundamental studies leading to specific practical applications in railroads. The basic idea was to surface engineer metals for enhanced surface properties. A micro- and nano- scale experimental approach has been used to achieve these objectives. Novel principles of nano technology are incorporated into the experiments. Friction has the potential to generate sufficient energy to cause surface reactions through high flash temperatures at the interface of two materials moving in relative motion. This allows surface modifications which can be tailored to be tribologically beneficial through a controlled process. The present work developed a novel methodology to generate a functional tribofilm that has combined properties of high hardness and high wear resistance. A novel methodology was implemented to distinguish sliding/rolling contact modes during experiments. Using this method, a super hard high-performance functional tribofilm with “regenerative” properties was formed. The main instrument used in this research for laboratory experiments is a tribometer, using which friction, wear and phase transformation characteristics of railroad tribo-pairs have been experimentally studied. A variety of material characterization techniques have been used to study these characteristics at both micro and nano scale. Various characterization tools used include profilometer, scanning electron microscope, transmission electron microscope, atomic force microscope, X-ray diffractometer, nanoindenter, and X-ray photon spectroscope. The regenerative tribofilms promise exciting applications in areas like gas turbines, automotive industry, compressors, and heavy industrial equipment. The outcome of this technology will be an economical and more productive utilization of resources, and a higher end performance.

ABSTRACT

In the past decade, the construction industry has been identified to be among the industries that are lagging in the application of modern information and communication technology as tools to enhance project performance. Where this technology has been applied, little has been done to meet up with the pace of advancements in information and communication technology.

This research looks at the extent to which information and communication technology (ICT) tools have being integrated for project enhancement in a major railway construction project. Most precisely, it looks at how ICT tools have affected communication and collaborative processes in the context of the soft skills processes and the hard skills processes. Enormous literature in this field of study was reviewed to set the base upon which to make the investigation. Findings show that ICT tools have been integrated just to a limited extent on the project which still used traditional management and project communication methods.; and there was room for integration of better tools as project participants were aware of some of these ICT tools that can enhance the performance of the project. Finally, an ICT infrastructure that encompasses all aspects of the project environment and the entire project lifecycle is proposed. This infrastructure enhances project performance by integrating all project stakeholders in the process of knowledge sharing and use in the project. The research also determines that most project organisations would refrain from integrating certain kinds of project enhancement tools because of he cost obtaining them as well as the cost to train employees on their usage.

This thesis explores ways to use ion implantation and nanosecond pulsed laser melting, both energetic beam techniques, to engineer defects in silicon. These defects are chosen to facilitate the use of silicon in optoelectronic applications for which its indirect bandgap is not ideal. Chapter 2 develops a kinetic model for the use of point defects as luminescence centers for light-emitting diodes and demonstrates an experimental procedure capable of high-throughput screening of the electroluminescent properties of such defects. Chapter 3 discusses the dramatic change in optical absorption observed in silicon highly supersaturated (i.e., hyperdoped) with the chalcogens sulfur, selenium, and tellurium and reports the first measurements of the optical absorption of such materials for photon energies greater than the bandgap of silicon. Chapter 3 examines the use of silicon hyperdoped with chalcogens in light detectors and concludes that while these devices display strong internal gain that is coupled to a particular type of surface defect, hyperdoping with chalcogens does not lead directly to measurable sub-bandgap photoconductivity. Chapter 4 considers the potential for Silicon to serve as the active material in an intermediate-band solar cell and reports experimental progress on two proposed approaches for hyperdoping silicon for this application. The main results of this chapter are the use of native-oxide etching to control the surface evaporation rate of sulfur from silicon and the first synthesis of monocrystalline silicon hyperdoped with gold.
Engineering and Applied Sciences

"Submitted in partial fulfillment of the requirements for the degree of Master of Business Administration from the Naval Postgraduate School, December 2008."
Advisor(s): Jones, Lawrence R. ; Wagner, Brett. "December 2008." "MBA professional report"--Cover. Description based on title screen as viewed on January 28, 2009. Includes bibliographical references (p. 29). Also available in print.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.
Vita.
Includes bibliographical references (p. 89-91).
The Naval Construction Force has traditionally depended on outside sources to obtain and analyze engineering data in contingency situations. The Navy has embarked on an initiative to develop Seabee Engineer Reconnaissance Teams to perform this function, both as a basis for projects slated for in-house construction and as a product to deliver to other organizations. Exercises and operations have thus far shown that the concept is viable, but Seabee Engineer Reconnaissance Teams have encountered problems with data gathering and reporting, and transmission of data and images. Concurrently, the Department of Defense is pursuing a transformation toward network-centric warfare. Network Centric Warfare represents a powerful set of warfighting concepts and associated military capabilities that allow warfighters to take full advantage of all available information in order to bring all available assets to bear in a rapid and flexible manner. This research explores the state of the practice of military engineer reconnaissance as described by established Army doctrine and as enacted by Navy Seabee Engineer Reconnaissance Teams. Commercial information technology applications are reviewed in the areas of geographic information systems, collaborative design, and wireless communications. Solutions are proposed for their potential to enable network centric engineer reconnaissance operations. Network Centric Warfare concepts provide a framework for analyzing the state of the practice in military engineer reconnaissance versus the state of the art in information technology. Current status is assessed and a methodology is proposed to move the Navy quickly forward on the continuum of the Network Centric Operations Maturity Model that enables shared situational awareness, with a brief discussion on the implications for decentralized decision-making.
by Keith W. Barton.
S.M.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.
Includes bibliographical references (p. 49).
Over the past century, there have existed two major types of structural engineers. Some, like Robert Maillart, contributed greatly to the advancement of new forms. Others, such as Peter Rice, produced their most innovative work in collaboration with architects. The present study analyzes the work and methodology of both groups of engineers, with the purpose of defining the common ground between them. Finally, there is a detailed discussion of the 'form-makers' and 'collaborators' in the context of the present day, in an effort to describe the basis for quality in structural engineering.
by Alice Tao.
M.Eng.

Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.
Includes bibliographical references (leaf 73).
by Hoi Wai Thomas Cheng.
M.Eng.and S.B.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020
Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 189-203).
Synthetic biology is an emerging field of research aimed to engineer biological systems by inserting programmed DNA molecules into living cells. These DNAs encode the production and subsequent interactions of biomolecules that allow the cells to have novel sensing, computing, and actuation capabilities. However, most success stories to date rely heavily on trial and error. This is mainly because genetic systems are context-dependent: the expression level of a synthetic gene often depends not only on its own regulatory inputs, but also on the expression of other supposedly unconnected genes. This lack of modularity leads to unexpected behaviors when multiple genetic subsystems are composed together, making it difficult to engineer complex systems that function predictably and robustly in practice. This thesis characterizes resource competition as a form of context dependence, and presents control theoretic approaches to engineer robust, context-independent gene networks. We first present a systems framework to model resource competition, which results in a hidden layer of unintended interactions among genetic subsystems. These unintended interactions lead to failure of the composed network in experiment. We then introduce a set of biomolecular controllers - designed to solve an output regulation problem in vivo - that can decouple a genetic subsystem's output from its context. We describe challenges applying classical control theory to engineer such controllers due to the physical constraints in living cells, and then present novel theory-guided engineering solutions. Finally, we point to additional design considerations when regulating multiple subsystems using multiple controllers in a single cell. These works have the potential to enhance the robustness of future synthetic biological systems and to fully unleash their power to address pressing societal needs in environment, energy, and health.
by Yili Qian.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering

For decades, Army Engineers have utilized the systems of the Critical Path Method (CPM) and multi-level Gantt chart planning system for its construction projects. While these methods are well accepted, they are not without their flaws. Research and literature in project management has given weight to several viable alternative options to planning projects. One such option, Critical Chain Project Management (CCPM), was developed to address the flaws of CPM by offering a holistic approach to project management based on strict resource control and the use of time buffers. This method attempts to eliminate multitasking and procrastination that can plague efficiency and offer managers more flexibly on tasks that otherwise had no leeway. CCPM may give project managers more flexibility and control while at the same time shortening the overall length of a project, saving time and money. The purpose of this thesis was to address the time saving and resource management benefits of utilizing CCPM over CPM and analyze the viability of those benefits being applied to U.S. Army Corps of Engineers construction project planning. Through the use of surveys of Army Engineer project supervisors, several key factors that cause delays because of CPM were identified and rated. The validity of CCPM based solutions to the same issues were also assessed by Army project supervisors in the survey. Analysis of the survey results indicated that CCPM may offer solutions to major issues that Army project supervisors face.