Design and Implementation of Tools for STM Studies in UHV and at the Solid-Liquid Interface

This thesis presents details of the design and development of novel tools and instruments for scanning tunneling microscopy (STM), and may be considered as a repository for several years' worth of development work. The author presents design goals and implementations for two microscopes. First, a novel Pan-type STM was built that could be operated in an ambient environment as a liquid-phase STM. Unique features of this microscope include a unibody frame, for increased microscope rigidity, a novel slider component with large Z-range, a unique wiring scheme and damping mechanism, and a removable liquid cell. The microscope exhibits a high level of mechanical isolation at the tunnel junction, and operates excellently as an ambient tool. Experiments in liquid are on-going. Simultaneously, the author worked on designs for a novel low temperature, ultra-high vacuum (LT-UHV) instrument, and these are presented as well. A novel stick-slip vertical coarse approach motor was designed and built. To gauge the performance of the motor, an in situ motion sensing apparatus was implemented, which could measure the step size of the motor to high precision. A new driving circuit for stick-slip inertial motors is also presented, that o ffers improved performance over our previous driving circuit, at a fraction of the cost. The circuit was shown to increase step size performance by 25%. Finally, a horizontal sample stage was implemented in this microscope. The build of this UHV instrument is currently being fi nalized. In conjunction with the above design projects, the author was involved in a collaborative project characterizing N-heterocyclic carbene (NHC) self-assembled monolayers (SAMs) on Au(111) films. STM was used to characterize Au substrate quality, for both commercial substrates and those manufactured via a unique atomic layer deposition (ALD) process by collaborators. Ambient and UHV STM was then also used to characterize the NHC/Au(111) films themselves, and several key properties of these films are discussed. During this study, the author discovered an unexpected surface contaminant, and details of this are also presented. Finally, two models are presented for the nature of the NHC-Au(111) surface interaction based on the observed film properties, and some preliminary theoretical work by collaborators is presented.

Design de interfaces dinâmicos em sistemas de gestão de conteúdos

Relatório de Estágio para a obtenção do grau de Mestre na área de Educação e Comunicação Multimédia

Tangible mobile app store design for China's new generation migrant worker

China has the largest numbers of Internet users and mobile phone subscribers in the world, as well as the most extensive peacetime internal migration on the planet. Mobile phone uses play a very important role in migrant responses to alienation and discrimination. There are 150 million to 200 million migrant workers in China, 60% of them are the second-generation migrant workers. They support the nation’s manufacturing and industry. The majority of these individuals is poor and is from rural areas of the country. These young people are currently ignored by mainstream mobile device manufacturers, even though this constituency will be a growing consumptive segment in the future. Thus, my research will target the new-generation migrant workers in China, and concentrates on their mobile lives to best develop a tangible mobile devices application store that will improve their mobile experiences.

Progetto DERNetSoft: design e sviluppo di un'app mobile per un futuro più sostenibile

Da anni ormai siamo inconsapevolmente "in guerra" con la natura. Sfruttiamo e sprechiamo risorse naturali senza alcuna considerazione per le conseguenze. Le città sono considerate le principali fonti dei problemi ambientali e la regolamentazione del consumo energetico urbano è fondamentale per affrontare il cambiamento climatico globale. DERNetSoft Inc, start-up californiana, ha intravisto il problema come un’opportunità per creare un proprio business il cui scopo è quello di contribuire a costruire un futuro a basse emissioni di carbonio, fornendo un servizio tecnologico scalabile e conveniente per consentire la riduzione delle emissioni di gas a effetto serra a livello mondiale. Per farlo vengono utilizzati i concetti di DER Energy e Aggregation Energy. Nel volume di tesi si affrontano e descrivono la progettazione di un’applicazione mobile, multipiattaforma, sviluppata con il framework React Native. L’app sviluppata è supportata da un’architettura basata su dei micro servizi implementati tramite il cloud di Google. La principale funzionalità dell’applicazione sviluppata è quella di notificare gli utenti di un evento ELRP che, attraverso incentivi economici, promuove la riduzione del consumo energetico durante i periodi di forte stress o emergenza della rete elettrica.

Fighting child marriage in developing countries: design and development of a mobile application

Child marriage is still a great issue in developing countries and even if the interventions to prevent it are having results, they are not enough to eliminate the problem. Among the strategies that seem to work most to fight child marriage, there is the empowerment of girls with information combined with education of parents and community. As smartphones are more accessible year after year in developing countries, this thesis wants to investigate if a mobile app could be effective in fighting child marriage and which characteristics such an app should have. The research was organized in four phases and used design and creation and case study methodologies. Firstly, the literature was analyzed and an initial design was proposed. Secondly, expert interviews were performed to gain feedback on the proposed design, and afterwards prototype was built. Thirdly, a case study in the Democratic Republic of Congo (DRC) was performed to test the prototype, gaining insights and improvements through group interviews with 26 girls aged 15-19. Finally, a first version of the app was developed and a second phase of the case study was run in the DRC to understand if the girls were able to use the app. This phase included 14 girls of which 6 had participated in the prototype testing and used questionnaires as a data generation method. The app was built following the Principles for Digital Development. Even if this app is built based on the case study in DRC is modular and easily adaptable to other contexts as it is not content-specific. It was shown that is worth continuing to study this topic and it was defined a conceptual framework for designing learning apps for developing countries, in particular, to fight child, early, and forced marriage.

Analysis and development of interface components and procedures for the design and commissioning toolchains in automation systems

The objective of the thesis project, developed within the Line Control & Software Engineering team of G.D company, is to analyze and identify the appropriate tool to automate the HW configuration process using Beckhoff technologies by importing data from an ECAD tool. This would save a great deal of time, since the I/O topology created as part of the electrical planning is presently imported manually in the related SW project of the machine. Moreover, a manual import is more error-prone because of human mistake than an automatic configuration tool. First, an introduction about TwinCAT 3, EtherCAT and Automation Interface is provided; then, it is analyzed the official Beckhoff tool, XCAD Interface, and the requirements on the electrical planning to use it: the interface is realized by means of the AutomationML format. Finally, due to some limitations observed, the design and implementation of a company internal tool is performed. Tests and validation of the tool are performed on a sample production line of the company.

Use Of Experimental Design To Optimize A Triple-potential Waveform To Develop A Method For The Determination Of Streptomycin And Dihydrostreptomycin In Pharmaceutical Veterinary Dosage Forms By Hplc-pad.

An HPLC-PAD method using a gold working electrode and a triple-potential waveform was developed for the simultaneous determination of streptomycin and dihydrostreptomycin in veterinary drugs. Glucose was used as the internal standard, and the triple-potential waveform was optimized using a factorial and a central composite design. The optimum potentials were as follows: amperometric detection, E1=-0.15V; cleaning potential, E2=+0.85V; and reactivation of the electrode surface, E3=-0.65V. For the separation of the aminoglycosides and the internal standard of glucose, a CarboPac™ PA1 anion exchange column was used together with a mobile phase consisting of a 0.070 mol L(-1) sodium hydroxide solution in the isocratic elution mode with a flow rate of 0.8 mL min(-1). The method was validated and applied to the determination of streptomycin and dihydrostreptomycin in veterinary formulations (injection, suspension and ointment) without any previous sample pretreatment, except for the ointments, for which a liquid-liquid extraction was required before HPLC-PAD analysis. The method showed adequate selectivity, with an accuracy of 98-107% and a precision of less than 3.9%.

Fretting fatigue in overhead conductors: Rig design and failure analysis of a Grosbeak aluminium cable steel reinforced conductor

The performance optimisation of overhead conductors depends on the systematic investigation of the fretting fatigue mechanisms in the conductor/clamping system. As a consequence, a fretting fatigue rig was designed and a limited range of fatigue tests was carried out at the middle high cycle fatigue regime in order to access an exploratory S-N curve for a Grosbeak conductor, which was mounted on a mono-articulated aluminium clamping system. Subsequent to these preliminary fatigue tests, the components of the conductor/clamping system, such as ACSR conductor, upper and lower clamps, bolt and nuts, were subjected to a failure analysis procedure in order to investigate the metallurgical free variables interfering on the fatigue test results, aiming at the optimisation of the testing reproducibility. The results indicated that the rupture of the planar fracture surfaces observed in the external At strands of the conductor tested under lower bending amplitude (0.9 mm) occurred by fatigue cracking (I mm deep), followed by shear overload. The V-type fracture surfaces observed in some At strands of the conductor tested under higher bending amplitude (1.3 mm) were also produced by fatigue cracking (approximately 400 mu m deep), followed by shear overload. Shear overload fracture (45 degrees fracture surface) was also observed on the remaining At wires of the conductor tested under higher bending amplitude (1.3 mm). Additionally, the upper and lower Al-cast clamps presented microstructure-sensitive cracking, which was folowed by particle detachment and formation of abrasive debris on the clamp/conductor tribo-interface, promoting even further the fretting mechanism. The detrimental formation of abrasive debris might be inhibited by the selection of a more suitable class of as-cast At alloy for the production of clamps. Finally, the bolt/nut system showed intense degradation of the carbon steel nut (fabricated in ferritic-pearlitic carbon steel, featuring machined threads with 190 HV), with intense plastic deformation and loss of material. Proper selection of both the bolt and nut materials and the finishing processing might prevent the loss in the clamping pressure during the fretting testing. It is important to control the specification of these components (clamps, bolt and nuts) prior to the start of large scale fretting fatigue testing of the overhead conductors in order to increase the reproducibility of this assessment. (c) 2008 Elsevier Ltd. All rights reserved.

Simultaneous steady state and dynamic design of process systems using structural indicators

The simultaneous design of the steady-state and dynamic performance of a process has the ability to satisfy much more demanding dynamic performance criteria than the design of dynamics only by the connection of a control system. A method for designing process dynamics based on the use of a linearised systems' eigenvalues has been developed. The eigenvalues are associated with system states using the unit perturbation spectral resolution (UPSR), characterising the dynamics of each state. The design method uses a homotopy approach to determine a final design which satisfies both steady-state and dynamic performance criteria. A highly interacting single stage forced circulation evaporator system, including control loops, was designed by this method with the goal of reducing the time taken for the liquid composition to reach steady-state. Initially the system was successfully redesigned to speed up the eigenvalue associated with the liquid composition state, but this did not result in an improved startup performance. Further analysis showed that the integral action of the composition controller was the source of the limiting eigenvalue. Design changes made to speed up this eigenvalue did result in an improved startup performance. The proposed approach provides a structured way to address the design-control interface, giving significant insight into the dynamic behaviour of the system such that a systematic design or redesign of an existing system can be undertaken with confidence.

Bioprocess-centered molecular design (BMD) for the efficient production of an interfacially active peptide

The efficient expression and purification of an interfacially active peptide (mLac21) was achieved by using bioprocess-centered molecular design (BMD), wherein key bioprocess considerations are addressed during the initial molecular biology work. The 21 amino acid mLac21 peptide sequence is derived from the lac repressor protein and is shown to have high affinity for the oil-water interface, causing a substantial reduction in interfacial tension following adsorption. The DNA coding for the peptide sequence was cloned into a modified pET-31(b) vector to permit the expression of mLac21 as a fusion to ketosteroid isomerase (KSI). Rational iterative molecular design, taking into account the need for a scaleable bioprocess flowsheet, led to a simple and efficient bioprocess yielding mLac21 at 86% purity following ion exchange chromatography (and >98% following chromatographic polishing). This case study demonstrates that it is possible to produce acceptably pure peptide for potential commodity applications using common scaleable bioprocess unit operations. Moreover, it is shown that BMD is a powerful strategy that can be deployed to reduce bioseparation complexity. (C) 2004 Wiley Periodicals, Inc.

Pressure-Frequency Sensing Subxiphoid Access System for Use in Percutaneous Cardiac Electrophysiology: Prototype Design and Pilot Study Results

We have designed, built, and tested an early prototype of a novel subxiphoid access system intended to facilitate epicardial electrophysiology, but with possible applications elsewhere in the body. The present version of the system consists of a commercially available insertion needle, a miniature pressure sensor and interconnect tubing, read-out electronics to monitor the pressures measured during the access procedure, and a host computer with user-interface software. The nominal resolution of the system is <0.1 mmHg, and it has deviations from linearity of <1%. During a pilot series of human clinical studies with this system, as well as in an auxiliary study done with an independent method, we observed that the pericardial space contained pressure-frequency components related to both the heart rate and respiratory rate, while the thorax contained components related only to the respiratory rate, a previously unobserved finding that could facilitate access to the pericardial space. We present and discuss the design principles, details of construction, and performance characteristics of this system.

Effect of framework design on crown failure

This study evaluated the effect of core-design modification on the characteristic strength and failure modes of glass-infiltrated alumina (In-Ceram) (ICA) compared with porcelain fused to metal (PFM). Premolar crowns of a standard design (PFMs and ICAs) or with a modified framework design (PFMm and ICAm) were fabricated, cemented on dies, and loaded until failure. The crowns were loaded at 0.5 mm min(-1) using a 6.25 mm tungsten-carbide ball at the central fossa. Fracture load values were recorded and fracture analysis of representative samples were evaluated using scanning electron microscopy. Probability Weibull curves with two-sided 90% confidence limits were calculated for each group and a contour plot of the characteristic strength was obtained. Design modification showed an increase in the characteristic strength of the PFMm and ICAm groups, with PFM groups showing higher characteristic strength than ICA groups. The PFMm group showed the highest characteristic strength among all groups. Fracture modes of PFMs and of PFMm frequently reached the core interface at the lingual cusp, whereas ICA exhibited bulk fracture through the alumina core. Core-design modification significantly improved the characteristic strength for PFM and for ICA. The PFM groups demonstrated higher characteristic strength than both ICA groups combined.

Design and implementation of a behaviorally typed programming system for web services

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia Informática.

Design of an extensible metadata editor based on RDF

The content of a Learning Object is frequently characterized by metadata from several standards, such as LOM, SCORM and QTI. Specialized domains require new application profiles that further complicate the task of editing the metadata of learning object since their data models are not supported by existing authoring tools. To cope with this problem we designed a metadata editor supporting multiple metadata languages, each with its own data model. It is assumed that the supported languages have an XML binding and we use RDF to create a common metadata representation, independent from the syntax of each metadata languages. The combined data model supported by the editor is defined as an ontology. Thus, the process of extending the editor to support a new metadata language is twofold: firstly, the conversion from the XML binding of the metadata language to RDF and vice-versa; secondly, the extension of the ontology to cover the new metadata model. In this paper we describe the general architecture of the editor, we explain how a typical metadata language for learning objects is represented as an ontology, and how this formalization captures all the data required to generate the graphical user interface of the editor.

Practical software improve design and performance of a randomly packed air stripping column for removing volatile organic compounds from water

STRIPPING is a software application developed for the automatic design of a randomly packing column where the transfer of volatile organic compounds (VOCs) from water to air can be performed and to simulate it’s behaviour in a steady-state. This software completely purges any need of experimental work for the selection of diameter of the column, and allows a choice, a priori, of the most convenient hydraulic regime for this type of operation. It also allows the operator to choose the model used for the calculation of some parameters, namely between the Eckert/Robbins model and the Billet model for estimating the pressure drop of the gaseous phase, and between the Billet and Onda/Djebbar’s models for the mass transfer. Illustrations of the graphical interface offered are presented.