2D materials for Magnetic and Optoelectronic Sensing Applications

In the last decade, the emerging classes of two-dimensional (2D) materials have been studied as potential candidates for various sensing technologies, including magnetic and optoelectronic detectors. Within the quickly growing portfolio of 2D materials, graphene and semiconducting transition metal dichalcogenides (TMDs) have emerged as attractive candidates for various sensor applications because of their unique properties such as extreme thickness, excellent electrical and optical properties. In this thesis, I have exploited the unique properties of graphene and TMDs materials to develop 2D detectors based on field effect transistors for sensing magnetic field and light. In the first part of this thesis I have shown how the sensitivity of the properties of 2D materials to their surrounding environment can be turned into a feature useful to create new types of magnetic field sensors. The first experimental demonstration of this concept involved the use of graphene deposited on hexagonal Boron Nitride (h-BN), where the inevitable contaminations occurring at the interface of the two materials was used to generate a large magnetoresistance (MR) for a magnetic field sensor. Specifically, I have demonstrated that the contaminations generate an inhomogeneity in the carrier mobility throughout the channel, which is a required ingredient for magnetic field sensing based on linear magnetoresistance (LMR). Another approach I used to make a LMR sensor was by exploiting the large dependence of the mobility in graphene on the Fermi level position. This concept was used to generate two parallel electron gases with different mobility by tuning the Fermi level with an electrical field employing a field effect transistor. The second part of the thesis is focussed on strategies to reduce the impact of the surrounding environment on the properties of 2D materials in order to improve their performance. In particular, I used a 2D heterostructure encapsulated in an ionic polymer to makeii a highly responsive graphene-TMD photodetector. In this device, the ionic polymer covering the heterostructure was employed to screen the long-lived charge traps that limit the speed of such detectors, resulting in a drastic improvement of the detector responsivity properties. Finally, some of the 2D materials properties are very sensitive to the configuration of the electronics measurement setup. For example, effects behind spintronic and valleytronic concepts require non-local electrical transport measurement. We built a novel circuit that enables the detection of such effects without concern about the spurious contributions.The Higher Committee For Education Development in Iraq (HCED

Development of a control box for a mechanical pressure scanner

In broad terms, the objective of this thesis is to be able to measure and analyse pressure signals coming from different points of a turbine. For this purpose it is needed to read and control a signal, that travels from the turbine to a mechanical multiplexer, which can receive a maximum of 48 pressure inputs and even though it has only one output, it is able to rotate and vary the output pressure which enables the analysis of different pressures in 48 alternate locations of our analysed turbine. This pressure signal, coming from the multiplexor, is sent to the pressure scan which transforms the pressure from a mechanical input into an analogue signal between -10 V and 10V. The signal is then adapted by an amplifier and a filter so that the microcontroller can receive and read it. Then the microcontroller generates a digital signal that will be afterwards read by an external PC via RS232 serial port using LabView to analyse the pressure signals. On the other hand, the multiplexor can rotate by two different means. The first one is just by pushing manually two switches called “manual step” (increase one position) and “manual home” (come back to 48, also called 0 or Home position) located at the optocoupler board. The other way is by sending the order, of step and home, from LabView to the microcontroller through the RS232 interface. Apart from this, we were also committed to find out the functionality of some cables which are coming from the position transmitter (belongs to the multiplexor) that are currently unconnected and study how to know exactly when the multiplexor is in home position.La finalidad de este proyecto es capturar y analizar señales de presión de distintos puntos de una turbina usando el programa gráfico Labview. Para conseguir dicho objetivo, es necesario trabajar por una parte con un sistema electromecánico (hardware), y por otro lado programar tanto un microcontrolador como la interfaz gráfica en Labview (software).Ingeniería Industria

Reliability investigations of bipolar silicon phototransistor arrays for space applications

[FR] Les travaux de thèse s'inscrivent dans le contexte d'une évaluation de la fiabilité de matrices de phototransistors bipolaires en technologie silicium pour des applications de codage optique angulaire en environnement spatial. Après un état de l'art relatif aux technologies des phototransistors et un rappel sur leur fonctionnement physique, les conditions environnementales spécifiques liées au domaine spatial sont décrites. La caractérisation des paramètres électro-optiques des phototransistors, associée à une phase préliminaire de métrologie, a été effectuée à partir de bancs dédiés. L'étude de la sensibilité aux charges mobiles de technologies issues de différents fondeurs, habituellement piégées aux interfaces et identifiée comme un mécanisme fortement pénalisant en terme de durée de vie opérationnelle, a permis d'optimiser et fiabiliser une nouvelle source européenne. Une méthodologie originale basée sur le concept des plans d'expérience D-optimal a été mise en œuvre et validée. L'objectif est d'estimer le taux de dégradation d'un ou de plusieurs paramètres clés du composant en fonction des conditions environnementales imposées par l'orbite de rotation du satellite à partir d'un nombre limité d'expériences réalisées au sol.[EN] The research activities presented in this thesis are related to the specific contextof the qualification tests, for space missions, of new sources of silicon phototransistor arraysfor optical angular encoders. Our studies on a first source revealed the fragility of thattechnology in active storage and ionizing radiation because of its sensitivity to oxidestrapped charges. Then, a study on a second set of components was performed in order toanalyze the reliability of phototransistors subjected to several constraints in terms of bothionizing and displacement doses. The methodology of Design of Experiments was for thefirst time implemented and validated in this context. Thanks to this methodology, it ispossible to obtain an estimate of the degradation of one or more key parameters of thecomponent in environmental conditions for a given mission profile with a limited number ofexperiments.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Power and Monitor Solution for the Proton Computed Tomography Project

The ProtonCT project is an academic endeavor carried out by the University of Bergen in collaboration with several universities and entities across the world. The end goal of the project is to improve dosage plans by directly measuring the relative stopping power of protons using a digital tracking calorimeter. Directly measuring relative stopping power as opposed to approximating it using CT numbers can provide a more accurate dosage plan. The digital tracking calorimeter will be able to do computed tomography scans of head-sized objects. The digital tracking calorimeter will utilize pixel detector sensors developed by CERN for the ALICE project. 43 pixel arrays, segmented into layers, measure the angle and energy of proton particles traversing through the layers. With 108 chips per layer, 4644 ALPIDE chips build up all the layers. At full load, the expected power draw is close to 2.5kW. This thesis explores the design of a user-controllable power delivery and monitoring system. Each layer consists of 12 ALPIDE strings, with 9 ALPIDE chips making up one string. A power delivery system capable of supplying one layer is realized by using a small form factor switch mode power supply unit. An FPGA design created by peer students connects the 43 power delivery systems to a graphical interface. A filter, monitor, and control solution is designed with a newly released AVR microcontroller unit. A custom PCB, named the Monitor Board, is designed to host the filter and the MCU with all its support circuitry. Using differential signaling, the 43 monitorboards communicate with a Xilinx Kintex UltraScale FPGA responsible for storing and relaying information over IPbus to the user. Each monitor board can switch the strings of its designated layer on or off. Diagnostics and soft startups/shutdowns can be executed through software. The back-biasing of an entire layer is customizable by using the microcontroller DAC and an onboard negative voltage supply. A temperature monitoring solution is designed with the use of a PT1000 element mounted close to the ALPIDE chips.Master's Thesis in PhysicsPHYS399MAMN-PHY

Low-cost Industrial controller based on the Raspberry Pi platform

Mestrado de dupla diplomação com o Centro Federal de Educação Tecnológica Celso Suckow da Fonseca - CEFET/RJThe low-cost automation field exhibits the need of innovation both in terms of hardware and software. There is a lack of devices that allow the development of control logic that is free from restrictions of domain-specific communication platforms and at the same time able to provide the capabilities aligned to the Industry 4.0 requirements. The objective of this work is to develop an inexpensive, small Industrial Controller that supports the execution of programs in different industrial programming languages. So, it is intended to develop, manufacture and control a low-cost but powerful Industrial Controller based on the use of the single-board computer Raspberry Pi. The study described in this document was carried out on the creation of a hardware platform that is capable of integrating with software frameworks compatible with standards updated and widely used in the industrial automation field. IEC 61131-3 is employed displaying the ease of use and implementation alongside multiple well established programming languages for automation through the OpenPLC platform while IEC 61449 is employed through the 4DIAC framework that has a clear and objective environment capable of providing the appropriate tools for implementation of a distributed control. It is employed the single-board computer Raspberry Pi, a robust device with adequate processing power and communication capability for the elaboration of a platform in the low-cost automation scope. The elaboration of the Industrial Shields, responsible for providing the controller I/O interface took into consideration maintenance concerns of controller integrity through the application of galvanic isolation in the automaton input and output sections. The proposed platform was successfully tested in an automation system prototype comprising Fischertechnik’s Punching Machine being possible to develop the control logic using IEC 61131-3 and IEC 61499.O campo de automação de baixo custo demonstra a necessidade de inovação em termos de hardware e software. Há uma falta de dispositivos que permitem o desenvolvimento de lógica de controle livre de restrições de plataformas de comunicação específicas de domínio e, ao mesmo tempo, capazes de fornecer os recursos alinhados aos requisitos da Indústria 4.0. O objetivo deste trabalho é desenvolver um pequeno Controlador Industrial de baixo custo que suporte a execução de programas em diferentes linguagens de programação industrial. Assim, pretende-se desenvolver, fabricar e controlar um Controlador Industrial de baixo custo, mas poderoso, baseado no uso do computador de placa única Raspberry Pi. O estudo descrito neste documento foi realizado na criação de uma plataforma de hardware que é capaz de se integrar com frameworks de software compatíveis com padrões atualizados e amplamente utilizados na área de automação industrial. A IEC 61131-3 é empregada exibindo a facilidade de uso e implementação juntamente com várias linguagens de programação bem estabelecidas para automação através da plataforma OpenPLC enquanto a IEC 61449 é empregada através da estrutura 4DIAC que possui um ambiente claro e objetivo capaz de fornecer as ferramentas apropriadas para implementação de um controle distribuído. É empregado o computador de placa única Raspberry Pi, um dispositivo robusto com capacidade de processamento e capacidade de comunicação adequados para a elaboração de uma plataforma no escopo de automação de baixo custo. A elaboração dos industrial shields, responsáveis por fornecer a interface de I/O do controlador levou em consideração as preocupações de manutenção da integridade do controlador através da aplicação de isolação galvânica nas seções de entrada e saída do autômato. A plataforma proposta foi testada com sucesso em um protótipo de sistema de automação compreendendo a Punching Machine da Fischertechnik sendo possível desenvolver a lógica de controle usando IEC 61131-3 e IEC 61499

Traveling-Wave Stark-Decelerated Molecular Beams for Cold Collision Experiments

Research of cold and ultracold molecules is currently a burgeoning field in experimental and theoretical physics. New experimental techniques, involving an increasingly large set of molecule types under high levels of control, are currently opening up new avenues of research with a vast array of potential applications. From understanding the role of quantum mechanics in molecular scattering and cold chemistry, to testing the fundamental symmetries of nature and realizing quantum computing with dipolar molecular qubits, experiments are accessing regimes not dreamed of even a few years ago. Theoretical interest and computing capabilities are also at an all time high, spurred on by the possibility of creating ultracold dipolar gases as tunable realizations of strongly interacting quantum Hamiltonians, creating exotic phases of matter, and the investigation of controlling molecular interactions with applied electromagnetic fields. Less than a decade ago, cold molecule experiments had seemingly reached a technological plateau, being capable of creating moderate densities of 106-107 molecules/cm3 at temperatures of 10-100 mK. With many applications requiring colder temperatures and higher densities, the field was ripe for new advances. Today, via a plethora of methods such as direct molecular laser cooling, electro-optical cooling, magneto- and photo-association, and new molecular beam deceleration techniques, the field is just beginning to have the tools capable of producing truly interesting systems for study. This work will discuss a couple of major steps taken in the direction of achieving scientific goals using cold molecules. The first experimental advancement discussed will be the development of a co-trap environment for studying interactions and collisions between ultracold atoms and Stark decelerated cold polar molecules. In this experiment, rubidium atoms are trapped using magnetic fields, and ammonia atoms are decelerated and trapped using electric fields. The two traps are spatially overlapped in order to investigate inter-species interactions. The co-trap environment provides exceedingly long interaction times, many orders of magnitude longer than typical beam-based interaction studies. As a result, it provides extremely high sensitivity to weak interaction mechanisms. The second experimental advancement discussed will be the development and construction of a new style of Stark decelerator, capable of producing much larger densities of cold molecules. This apparatus has the potential to expand the realm of possible experiments with chemically interesting species, and provide an unprecedented amount of control over molecular beams and traps. The gains haven't come easily though, as a new class of custom high-voltage amplifiers have needed to be developed. This part of the experiment alone took approximately two years of consistent effort to bring to fruition. After many years of development, this experiment is poised to come online, finally fulfilling its potential.</p

Smart Sensors for Healthcare and Medical Applications

This book focuses on new sensing technologies, measurement techniques, and their applications in medicine and healthcare. Specifically, the book briefly describes the potential of smart sensors in the aforementioned applications, collecting 24 articles selected and published in the Special Issue “Smart Sensors for Healthcare and Medical Applications”. We proposed this topic, being aware of the pivotal role that smart sensors can play in the improvement of healthcare services in both acute and chronic conditions as well as in prevention for a healthy life and active aging. The articles selected in this book cover a variety of topics related to the design, validation, and application of smart sensors to healthcare

Design and implementation of a PC-based heart rate variability and respiration recording system

Cataloged from PDF version of article.Determination of the exact effects of respiration rate on the heart rate variability requires comprehensive experimental studies. In this context, these two quantities should be analyzed simultaneously. In this thesis, design and implementation of a new PC-based heart rate variability recording system with respiration is described. The respiration rate is detected by a thermocouple placed in a nasal tube, whereas a single-channel electrocardiogram (ECG) signal is recorded for heart rate variability analysis in the system. The PC-based data acquisition part, which was designed in compliance to patient safety standards, has a Universal Serial Bus (USB) interface. The speed of data acquisition and patient comfort during recording make the system advantageous. The HRVs of different patients in both spontaneous and controlled breathing conditions were analyzed after short-term recordings with the system. Differences were observed in both its time-domain parameters and power spectral components.Korkmaz, Okay TuncaM.S

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences