Assessment of Durable SiC JFET Technology for +600 C to -125 C Integrated Circuit Operation

Electrical characteristics and circuit design considerations for prototype 6H-SiC JFET integrated circuits (ICs) operating over the broad temperature range of -125 C to +600 C are described. Strategic implementation of circuits with transistors and resistors in the same 6H-SiC n-channel layer enabled ICs with nearly temperature-independent functionality to be achieved. The frequency performance of the circuits declined at temperatures increasingly below or above room temperature, roughly corresponding to the change in 6H-SiC n-channel resistance arising from incomplete carrier ionization at low temperature and decreased electron mobility at high temperature. In addition to very broad temperature functionality, these simple digital and analog demonstration integrated circuits successfully operated with little change in functional characteristics over the course of thousands of hours at 500 C before experiencing interconnect-related failures. With appropriate further development, these initial results establish a new technology foundation for realizing durable 500 C ICs for combustion engine sensing and control, deep-well drilling, and other harsh-environment applications

Strange Bodies and Familiar Spaces: W. J. R. Simpson and the threat of disease in Calcutta and the tropical city, 1880 - 1910

This thesis discusses the role of urban sanitation in tropical cities, especially Calcutta. Focusing particularly on the provision of milk, the author argues that hygienic practice, and the culture of nineteenth-century tropical medicine, created more diffuse racial deliniations than usually assumed by historians [abstracted by librarian]

Engineering enzyme access tunnels

Enzymes are efficient and specific catalysts for many essential reactions in biotechnological and pharmaceutical industries. Many times, the natural enzymes do not display the catalytic efficiency, stability or specificity required for these industrial processes. The current enzyme engineering methods offer solutions to this problem, but they mainly target the buried active site where the chemical reaction takes place. Despite being many times ignored, the tunnels and channels connecting the environment with the active site are equally important for the catalytic properties of enzymes. Changes in the enzymatic tunnels and channels affect enzyme activity, specificity, promiscuity, enantioselectivity and stability. This review provides an overview of the emerging field of enzyme access tunnel engineering with case studies describing design of all the aforementioned properties. The software tools for the analysis of geometry and function of the enzymatic tunnels and channels and for the rational design of tunnel modifications will also be discussed. The combination of new software tools and enzyme engineering strategies will provide enzymes with access tunnels and channels specifically tailored for individual industrial processes

Current Source Logic Gate

A current source logic gate with depletion mode field effect transistor ("FET") transistors and resistors may include a current source, a current steering switch input stage, and a resistor divider level shifting output stage. The current source may include a transistor and a current source resistor. The current steering switch input stage may include a transistor to steer current to set an output stage bias point depending on an input logic signal state. The resistor divider level shifting output stage may include a first resistor and a second resistor to set the output stage point and produce valid output logic signal states. The transistor of the current steering switch input stage may function as a switch to provide at least two operating points

Encapsulation system for the immunoisolation of living cells

The present invention is drawn to a composition of matter comprising high viscosity sodium alginate, cellulose sulfate and a multi-component polycation. Additionally, the present invention provides methods for making capsules, measuring capsule permeability to immunologically-relevant proteins and treating disease in an animal using encapsulated cells. Over one thousand combinations of polyanions and polycations were examined as polymer candidates suitable for encapsulation of living cells and thirty-three pairs were effective. The combination of sodium alginate, cellulose sulfate, poly(methylene-co-guanidine) hydrochloride, calcium chloride, and sodium chloride produced the most desirable results. Pancreatic islets encapsulated in this multicomponent capsule demonstrated glucose-stimulated insulin secretion in vitro and reversed diabetes without stimulating immune reaction in mice. The capsule formulation and system of the present invention allows independent adjustments of capsule size, wall thickness, mechanical strength and permeability, and offers distinct advantages for immunoisolating cells

Demonstration of 4H-SiC JFET Digital ICs Across 1000 C Temperature Range Without Change to Input Voltages

Operational testing of prototype 4H-SiC JFET ICs across an unrivaled ambient temperature span in excess of 1000 C, from -190 C to +812 C, has been demonstrated without any change/adjustment of input signal levels or power supply voltages. This unique ability is expected to simplify infusion of this IC technology into a broader range of beneficial applications

Further Analyses of the NASA Glenn Research Center Solar Cell and Photovoltaic Materials Experiment Onboard the International Space Station

Accurate air mass zero (AM0) measurement is essential for the evaluation of new photovoltaic (PV) technology for space solar cells. The NASA Glenn Research Center (GRC) has flown an experiment designed to measure the electrical performance of several solar cells onboard NASA Goddard Space Flight Center's (GSFC) Robotic Refueling Mission's (RRM) Task Board 4 (TB4) on the exterior of the International Space Station (ISS). Four industry and government partners provided advanced PV devices for measurement and orbital environment testing. The experiment was positioned on the exterior of the station for approximately eight months, and was completely self-contained, providing its own power and internal data storage. Several new cell technologies including four-junction (4J) Inverted Metamorphic Multi-Junction (IMM) cells were evaluated and the results will be compared to ground-based measurement methods

Using urban climate modelling and improved land use classifications to support climate change adaptation in urban environments: A case study for the city of Klagenfurt, Austria

This study outlines the results of current and future climate scenarios, and potentially realizable climate adaptation measures, for the city of Klagenfurt, Austria. For this purpose, we used the microscale urban climate model (MUKLIMO_3), in conjunction with the cuboid method, to calculate climate indices such as the average number of summer and hot days per year. For the baseline simulation, we used meteorological measurements from 1981 to 2010 from the weather station located at Klagenfurt Airport. Individual building structures and canopy cover from several land monitoring services were used to derive accurate properties for land use classes in the study domain. To characterize the effectiveness of climate adaptation strategies, we compared changes in the climate indices for several (future) climate adaptation scenarios to the reference simulation. Specifically, we considered two major adaptation pathways: (i) an increase in the albedo values of sealed areas (i.e., roofs, walls and streets) and (ii) an increase in green surfaces (i.e., lawns on streets and at roof level) and high vegetated areas (i.e., trees). The results indicate that some climate adaptation measures show higher potential in mitigating hot days than others, varying between reductions of 2.3 to 11.0%. An overall combination of adaptation measures leads to a maximum reduction of up to 44.0%, indicating a clear potential for reduction/mitigation of urban heat loads. Furthermore, the results for the future scenarios reveal the possibility to remain at the current level of urban heat load during the daytime over the next three decades for the overall combination of measures

Автоматизація підготовки даних для географічного блока ахівної бази даних

Прокоп, Ю. В. Автоматизація підготовки даних для географічного блока архівної бази даних = Automation of data preparation for the geographic block of the archival database / Ю. В. Прокоп, О. Г. Трофименко, А. С. Прокоп // Зб. наук. пр. НУК. – Миколаїв : НУК, 2020. – № 2 (480). – С. 107–114.Анотація. Створення архівних інформаційно-пошукових систем є одним з актуальних напрямів розвитку української архівної галузі. Проте реалізація його потребує внесення до баз даних величезного обсягу інформації, причому цей процес нині не автоматизований, а тому потребує значних людських ресурсів для введення даних вручну. Метою роботи є дослідження автоматизації процесу підготовки даних для географічного блока архівної інформаційно-пошукової системи із джерел різного формату: електронних реєстрів, вебсторінок, паперових друкованих видань, рукописних архівних документів тощо. Пропонується підсистема для підготовки даних, яка складається з модулів пошуку джерел інформації, видобування даних, ідентифікації даних і внесення інформації до бази. Значну частину роботи в підсистемі було автоматизовано, тому вона вже не потребує ручного введення даних. Вибір методу видобування і попереднього опрацювання даних залежить від джерела інформації. З урахуванням специфіки завдання можна припускати, що більшість джерел є або друкованими виданнями, або рукописними архівними документами. Тому першим кроком для їх опрацювання має бути сканування і розпізнавання тексту за допомогою поширених програмних засобів або нейронної мережі. Отриманий із джерел неструктурований текст методом синтаксичного аналізу трансформується у структурований і заноситься в таблиці певного шаблону. Видобуті дані мають бути ідентифіковані, відомості про тотожні адміністративні одиниці – об’єднані та внесені в базу даних. Запропонована підсистема підготовки даних була реалізована на прикладі підготовки географічних відомостей для Миколаївської області. Практична значимість отриманих результатів полягає в тому, що використання запропонованого алгоритму дозволить автоматизувати заповнення географічного блока даними інших регіонів для використання в регіональних тематичних архівних базах даних і загальнодержавній архівній інформаційно-пошуковій системі.Abstract. The creation of archival information retrieval systems is one of the actual directions of the development of the Ukrainian archival system. However, its implementation requires entering a huge amount of information into databases. Moreover, this process is not currently automated and therefore requires significant human resources to enter data manually. The work aims to study the automation of the data preparation process for the geographical block of the archival information retrieval system from sources of various formats: electronic registers, web pages, paper books, handwritten archival documents, etc. A subsystem for data preparation is proposed. It consists of modules for searching for information sources, data extraction, data identification, and entering information into the database. Much of the work in the subsystem is automated and does not require manual data entry. The choice of method of data extraction and pre-processing depends on the source of information. Given the specifics of the task, it can be assumed that the vast majority of sources will be either printed publications or handwritten archival documents. Therefore, the first step to their processing should be scanning and text recognition using common software or neural network. Unstructured text obtained from sources is automatically transformed by syntactical analysis into structured text, which is entered in the table of a certain template. The extracted data must be identified, information about identical administrative units must be combined and entered into a database. The proposed subsystem of data preparation was implemented on the example of the preparation of geographical information for the Mykolayiv region. The significance of the obtained results is that the use of the proposed algorithm will automate the filling of the geographical block with data from other regions for use in regional thematic archival databases and the national archival information retrieval system