Analyzing capacitor-based reconfigurable antennas using graph models

This paper discusses reconfigurable antennas using variable capacitors or varactors to achieve reconfiguration. We propose graph models as tools to understand reconfigurable antenna topologies and their configurations. Guidelines are set to model this type of reconfigurable antennas using graphs and examples are studied to investigate their optimal performance

Prediction of physical-chemical and fire hazard characteristics by carbon chain rules. 2. Carboxylic acids

Investigation of the dependence of physico-chemical and fire hazard properties from the chemical structure of carboxylic acids is carried out. Forecasting of the boiling temperature, the flash point, the temperature and the concentration flammability limits, the heats of combustion and vaporization is performed by the carbon chain rules (CCR). The following empirical equations for the calculation of physico-chemical and fire hazard indices from the conventional carbon chain and from the number of carbon atoms are proposed for the convenience of practical application of the CCR. A comparative analysis of the proposed methods for the flash point calculating and the already known methods of GOST 12.1.044-89, Mendeleev and ACD/Lab 2014 is carried out. It is shown, basically, that the new methods give more accurate calculation results than the comparison design procedures. © Siberian Federal University. All rights reserve

1867, l’année de tous les Rapports. Les lettres et les sciences à la fin du Second Empire

En juillet 1865, le ministre de l’Instruction publique Victor Duruy propose, au Conseil des ministres, « de faire l’histoire des progrès de toutes les sciences depuis vingt ans », dans le cadre de la préparation de l’Exposition universelle de 1867. Vers la fin octobre, il adresse à Napoléon III un rapport dans lequel il demande à l’empereur d’« autoriser le ministère de l’Instruction publique à être exposant » lors de la prochaine Exposition universelle à Paris. Une fois ce rapport approuvé par Napoléon III, il informe, en décembre, le commissaire général de la future Exposition universelle, le conseiller d’État Frédéric Le Play, que son ministère déposera une série de Rapports « sur les principales œuvres produites par l’esprit français ». De cette initiative sortiront 29 Rapports, plus ou moins importants en volume, écrits par des auteurs plus ou moins connus aujourd’hui. Ce corpus considérable a été sorti de l’oubli et étudié pendant trois ans par un groupe interdisciplinaire composé d’une quinzaine de chercheurs (historiens, historiens des sciences, de la philosophie et de la littérature). Il fournit un excellent état des préoccupations concernant les sciences et les lettres à la veille de la guerre de 1870. Les résultats de l’enquête permettent au lecteur d’aujourd’hui d’évaluer le patrimoine d’un XIXe siècle dont nous sommes les héritiers, aussi bien en ce qui concerne les conceptions relatives aux lettres, aux sciences et aux techniques, que pour les relations entre la recherche, l’université et la société

Ionoluminescence: A New Tool for Nuclear Microprobes in Geology

When an ion beam in the energy range of a few MeV/amu impacts on a mineral, visible light can often be observed. This light, induced by energetic ions, is termed ionoluminescence (IL). The intensity and wavelength of the ionoluminescent light provide information concerning the nature of luminescence centers, such as trace substituents and structural defects, found in the mineral. This makes IL a useful complement to other methods of ion beam analysis (IBA), such as particle induced X-ray emission (PIXE) and Rutherford backscattering (RBS), in characterizing geological samples. In the present study, a proton or alpha particle beam was used for the IL excitation and IBA with a nuclear microprobe. The results obtained with IL were compared with those of cathodoluminescence (CL) and photoluminescence (PL)

Effect of the anisotropy of monocrystalline silicon mechanical properties on the dynamic characteristics of a micromechanical gyroscope

The aim of the research was to determine the effect of temperature on mechanical properties of a micromechanical gyroscope with the sensing element mounted on a silicon wafer, with the crystallographic orientation of (100) (110) (111). The research is of current relevancy since the metrological characteristics that depend on the eigenfrequencies over the full temperature range are to be controlled. The temperature-modal analysis of the micromechanical gyroscope model was performed with ANSYS program. The temperature dependence for eigenfrequencies was obtained. The dependence of the scale factor on temperature for the most temperature-independent variant of sensor positioning on the wafer was determined. The developed mathematical model was used to find the forms of the output oscillations of the gyroscope

New equation for determination of overpressure of fuel-air mixture blast

The problems of assessing the consequences of fuel-air mixtures and their prevention are topical and of practical interest. Such the explosions pose a real danger during processing, transportation and storage of fuels at various industrial and civil facilities. Forecast of possible consequences of explosions of fuel-air mixtures is a key element in development of protective measures. Today, various calculation methods have been developed and approved by different departments and organizations. The authors of the article have previously verified methods of Gosatomnadzor (RB G-05-039-96), Rostechnadzor (RD 03-409-01, PB 09-540-03, Method for assessment of consequences of accidental explosions of fuel-air mixtures, General explosion safety rules for explosive chemicals, petrochemicals and refineries), EMERCOM of Russia (GOST R 12.3.047-98, GOST R 12.3.047-2012, SP 12.13130.2009), Netherlands Organisation for Applied Scientific Research, Dorofeev, Baker-Strehlow and Baker-Strehlow-Tang for prediction of consequences of air-fuel mixture explosions at the example of real explosions. It is established that the detonation regime is best described by the Dorofeev's method and multi-energy method of Netherlands Organisation for Applied Scientific Research (ME-TNO) for deflagration regime. Thus, it is promising to create a synthesis method that could combine approaches of the methods. Detonation mode was picked out using the ME-TNO method and replaced by Dorofeev's method. Such a technique allowed proposing a new equation for predicting explosion pressure of fuel-air mixtures. As a result of the research, a new equation is proposed. An equation allows calculating the overpressure of explosion, which more accurately predicts the consequences of fuel-air explosions at petroleum and gas, petrochemical and chemical industries

The behavior of radioactive metals (Am, Eu, Sr) during the processing of radioactive graphite in salt melts

The behavior of Am, Eu, Sr radionuclides was investigated by thermodynamic modeling method at heating of radioactive graphite in NaCl - KCl - Na2CO3 - K2CO3 molten salt with additives of nickel oxide NiO. The integrated thermodynamic analysis was carried out by means of TERRA software in temperature range 373-3273 K to determine possible composition of condensed and gaseous phases. It was established that americium is in gaseous state in temperature range 2773-3273 K. Europium is in the forms of gaseous EuO and Eu in temperature range 2373-3273 K. Strontium is in the forms of gaseous SrCl2, SrCl, Sr, SrO in temperature range 2373-3273 K. © Published under licence by IOP Publishing Ltd

Temperature Flammability Limits are Derivatives from Flash Point

Наступление керосиновой эры привело не только повсеместному использованию керосиновых приборов, но к появлению новой причины взрывов и пожаров в быту и на производстве, которая была связана с несовершенством конструкций керосиновых ламп, керогазов и использованием небезопасного керосина. Основным критерием безопасности керосина выступила температура вспышки. При изучении этого критерия пожаровзрывоопасности были выявлены низшая и высшая температура вспышки или другими словами низший и верхний температурные пределы воспламенения.The advent of the kerosene era led not only to the widespread use of kerosene devices, but to the emergence of a new cause of explosions and fires in everyday life and production, which was associated with imperfect kerosene lamp designs, kerosene gases and the use of unsafe kerosene. The main criterion for the safety of kerosene was the flash point. In studying this criterion of fire and explosion hazard, a lower and higher flash point or, in other words, the lower and upper flammability temperature limits were detected

The German Code of Flammable and Combustible Liquids

Корни эволюции немецкой классификации легковоспламеняющихся/горючих жидкостей (ЛВЖ/ГЖ) связаны с началом керосиновой эры, чему способствовало два важных события: изобретение керосиновой лампы в 1853 году и американская нефтяная революция 1859 года. Эти события обусловили массовое вхождение керосина в повседневный быт людей. Побочным эффектом явился рост пожаров и взрывов, связанных с несовершенством керосиновых приборов, а также за счет применения «небезопасного» керосина. В связи с этим во многих странах начались работы по совершенствованию керосиновых прибор и разработке методов определения безопасного керосина. Первоначально появились огненные тесты. Плохая сходимость и воспроизводимость этих тестов поставила задачу по поиску новых критериев безопасного керосина. В результате решения этой задачи появились хорошо известные температура вспышки и температура воспламенения. За точку отчета безопасности керосина по температуре вспышки бралась комнатная температура. Первая немецкая керосиновая классификация появилась в 1903 году в Пруссии, по которой осветительные масла (керосины) по температуре вспышки делились на 3 класса. В начале 20-го столетия жидкости с температурой вспышки более 140оС выделяются в IV класс, а в 1925 году верхние границы для 2 и 3 классов были понижены до 55 и 100оС соответственно. В дальнейшем обновлённая прусская классификация была распространена на все ЛВЖ/ГЖ, а классы 1-3 были переименованы в А1–А3. В таком виде классификация ЛВЖ применялась в Третьем рейхе и ФРГ. В послевоенный период был добавлен новый класс В (жидкости с tвсп < 21оС и неограниченно растворимые в воде при 15оС). Таким образом, в основе современной немецкой классификации ЛВЖ/ГЖ лежит критерий для «безопасного» керосина, разработанный в Германии во второй половине 19-го столетия.The roots of the evolution of the German flammable and combustible liquids classification are associated with the beginning of the kerosene era, which was promoted by two important events: the invention of a kerosene lamp in 1853 and the American oil revolution of 1859. These events determined the mass entry of kerosene into the everyday life of people. A side effect was the growth of fires and explosions related to the imperfection of kerosene devices, as well as through the use of «unsafe» kerosene. In this regard, work on improving kerosene instruments and developing methods for determining safe kerosene has begun in many countries. Originally there were fire tests. Poor convergence and reproducibility of these tests set the task of finding new criteria for safe kerosene. As a result of solving this problem, a well-known flash and fire points appeared. The room temperature was taken as the reference point of kerosene safety by the flash point. The first German kerosene classification appeared in 1903 in Prussia, according to which the lighting oils (kerosene) were divided into three classes according to the flash point. At the beginning of the 20th century liquids with a flash point of more than 140°C were separated into the IV class, and in 1925 the upper limits for II and III grades were lowered to 55 and 100°C, respectively. In the future, the updated Prussian classification was extended to all flammable and combustible liquids, and classes 1-3 were renamed A1-A3. In this form, the classification was applied in the Third Reich and the Federal Republic of Germany. In the post-war period, a new class B (liquids with FP<21°C and unlimitedly soluble in water at 15°C). Thus, the basis for the modern German flammable and combustible liquids classification is the criterion for «safe» kerosene, developed in Germany in the second half of the 19th century