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Статті в журналах з теми "Primary measuring converter"
1
Solovev, Denis B., and Alena E. Merkusheva. "Novel Active Current Transducers for Diesel Power Stations." International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no. 1 (March 1, 2016): 152. http://dx.doi.org/10.11591/ijpeds.v7.i1.pp152-158.
Повний текст джерелаАнотація:
Autonomous diesel power plants found the active application at the organization of autonomous power supply of the mining enterprises. In article the problem of increase of efficiency of use of control units is considered by the active power of synchronous generators of diesel power plants. As a solution the new innovative offer in the form of the developed device of the measuring converter of active current which is one of the main components of game-trolno-measuring equipment of diesel power plants is offered. The developed scheme is simpler, in comparison with the similar converters of active current executed on the basis of current transformers. In the developed scheme of the measuring converter it is offered to use the differentiating induction converters of current as primary measuring converters. It allows to reduce many times number of the elements entering the standard scheme, and also mass-dimensional characteristics of the device
2
Inozemtsev, Maxim, Natalia Grigoreva, Natalia Volynkina, and Atabek Alibaev. "Selection and experimental study of the linear displacement converter for the automated monitoring system of mine roofs." E3S Web of Conferences 315 (2021): 03006. http://dx.doi.org/10.1051/e3sconf/202131503006.
Повний текст джерелаАнотація:
The justification of the linear displacement sensors installation in mine workings is described in this paper. The required technical characteristics of the sensors are given. The main types of primary linear displacement converters are presented. The choice of inductive solenoid-type converters and sensors based on linear differential transformers (LVDT) is justified. The advantages and disadvantages of inductive transducers, their accuracy and measurement limits are described, and measuring methods of inductance of the solenoid-type transducers and the converter output signal based on LVDT are considered. The results of sensors experimental studies based on the solenoid-type inductive transducers are presented.
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Manuliak, I. Z., S. I. Melnychuk, Yu Yo Striletskyi, and V. M. Harasymiv. "Gas flow measuring system using signal processing on the basis of entropy estimations." Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, no. 5 (2020): 125–30. http://dx.doi.org/10.33271/nvngu/2021-5/125.
Повний текст джерелаАнотація:
Purpose. To increase the accuracy of gas flow measurement in tachometric transducers based on the improvement of structural, hardware and algorithmic support of information and measuring systems. Methodology. The gas consumption value is determined by the parameters of information and measurement signals. Sensor signals interacting with the environment are traditionally processed on the basis of amplitude and frequency methods. The research methodology is based on the information theory, methods of statistical and spectral analysis, digital signal processing, the theory of gas dynamics, based on mathematical modeling in a computational experiment, as well as the theory of errors and measurement results uncertainty. The statistical characteristics of the measuring signals of the converter presented in the unitary basis are studied. Findings. The conducted research resulted in development of an information-measuring system to control the sensitivity threshold of the transducers of the primary volume and the volume of gas consumption based on the developed primary transducer, which allows providing relative standard uncertainty of cost determination within 0.5%. A special processor has been developed to calculate the entropy estimates of signal information. Originality. For the first time, a method for the formation and processing of information-measuring signals, which is based on the use of pressure pulsations due to the movement of the measuring element of the converter in the toroidal measuring cell, is proposed. Implementation of the measuring element of a spherical converter, whose density is almost commensurable with the density of the controlled medium is offered. Practical value. The proposed method allows providing a lower sensitivity threshold compared to the industrial implementation of tachometric type transducers.
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Sedalishchev, V. N., Ya S. Sergeeva, D. O. Strahatov, and S. P. Pronin. "Specifics of Construction of Measuring Transducers with Logometric Output Based on Interconnected Piezoresonators." Izvestiya of Altai State University, no. 4(120) (September 10, 2021): 53–58. http://dx.doi.org/10.14258/izvasu(2021)4-08.
Повний текст джерелаАнотація:
The paper presents the results of simulation modeling of measuring devices. The simulation modeling is based on the use of coupled oscillations in systems with two degrees of freedom. Methods of controlling the parameters of the oscillatory system of the converter based on interconnected piezoresonators are considered. A comparative assessment of the metrological characteristics of possible variants of piezoresoanase sensors with logometric (differential) output is conducted.
It is shown that when the Q-factor of the oscillatory system of the primary converter is affected, a higher sensitivity of the measuring process is provided by the control of the active resistance of the coupling element replacement circuit between the resonators. In this case, it is proposed to use the ratio of the oscillation amplitudes of one of the interconnected resonators measured at the frequencies of common-mode and antiphase oscillations in the system as the output signal of the sensor. When the frequency-setting parameters of the converter are affected, it is recommended to use the ratio of the oscillation amplitudes of two interconnected piezoresonators measured at one of the normal frequencies of synchronized oscillations in the system to generate the output signal.
There are several advantages of measuring devices of this type, such as high sensitivity, simplicity of design, low cost, manufacturability, and operational applicability for harsh conditions.
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Gornostaev, A. I. "Optimization of the structure of the unified multichannel interface temperature control module for measuring instruments of spacecraft." Spacecrafts & Technologies 3, no. 3 (2019): 171–83. http://dx.doi.org/10.26732/2618-7957-2019-3-171-183.
Повний текст джерелаАнотація:
In the development of a unified multi-channel interface temperature control module for measuring instruments, built on a main-modular principle on the basis of the central instrument module and used on spacecraft for various purposes, the primary task is to determine its structure, which allows to provide temperature control on the elements of the spacecraft design in different measurement ranges and with different requirements for accuracy and stability of measurement. The article is devoted to the analysis of general requirements to the structure of the multi-channel interface temperature control module, in which the measuring channels can have different technical characteristics and the choice of variants for measuring the resistance of thermal converters to ensure the elimination of the systematic component of the measurement error. It is shown that in the structure of a unified multichannel interface temperature control module there should be a multichannel measurement scheme forming several measurement channels with different technical characteristics operating on a common channel of analog-to-digital conversion. To match the measuring channels with different input resistances and operating in different measurement ranges with the common channel of the analog-to-digital converter, it is necessary to use a controlled normalizing amplifier. To eliminate the systematic component of the measurement error, it is necessary to use three- or four-wire variants of the measurement schemes of thermal resistance converters, which allow the automatic compensation of the measurement error introduced by the resistances of the wires of the communication lines of the measuring cables, and the automatic calibration of the measurement error introduced by the measuring channels. To compensate for the nonlinear component of the measurement error introduced by thermal resistance converters, it is necessary on the basis of piecewise linear approximation of their nominal static characteristics to divide the operating ranges of measurement into subranges and to carry out automatic calibration measurement errors in each subrange separately.
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Dreyzin, V. E., Mohammed Al Kadhimi Ali Noori, and V. E. Bondyrev. "Ionosphere monitoring sensor, placed on nanosatellites." Monitoring systems of environment, no. 2 (June 24, 2021): 54–65. http://dx.doi.org/10.33075/2220-5861-2021-2-54-65.
Повний текст джерелаАнотація:
In this paper, we propose a sensor for the density and composition of the upper atmosphere (ionosphere), designed for installation on nanosatellites. The relevance and existing problems of direct instrumental studies of the ionosphere at altitudes of 150-500 km are shown. Of the existing types of vacuum meters, the most suitable for autonomous operation at these altitudes are ionization vacuum meters with inverse magnetron primary converters with a cold cathode. However, the existing industrial types of such vacuum meters are unsuitable for operation in the ionosphere due to high concentration of charged particles in the air, resulting in large distortions of the readings. In addition, they have large weight and size characteristics and energy consumption, which exclude the possibility of their installation on nanosatellites. To solve these problems, a mathematical model of the electrophysical processes, occurring in the core of such a converter, was developed which significantly reduced its weight and size characteristics and energy consumption. And to eliminate the influence of charged particles, it is equipped with an electron-ion trap, which additionally made it possible to measure the concentration of electrons and ions in the environment. The design of such a combined converter is described, and calculations of the electric and magnetic fields in the core of the vacuum gauge converter and the electric fields in the interelectrode space of the trap are performed. A method for calculating the current values of such a combined converter has been developed, which makes it possible to estimate the required measurement ranges of the sensor measuring channels. The results obtained allow us to proceed with its experimental design.
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Isaiev, V. V., and О. М. Velychko. "RESEARCH OF THE STATE PRIMARY STANDARD OF UNIT OF ALTERNATING CURRENT." Key title Zbìrnik naukovih pracʹ Odesʹkoï deržavnoï akademìï tehnìčnogo regulûvannâ ta âkostì -, no. 2(17) (2020): 14–22. http://dx.doi.org/10.32684/2412-5288-2020-2-17-14-22.
Повний текст джерелаАнотація:
The article is devoted to the results of the research in order to solve the problem of metrological support of production and operation of thermoelectric power converters, precision meters and AC power sources in the branches of the national economy. The optimal solution to the problem of metrological support is to create a national standard unit of alternating current. The article conducts theoretical research, comparison with foreign analogues and analysis of methods for measuring and reproducing the strength of alternating current. The analysis of the precision means intended for measurement, reproduction and comparison of force and voltage of alternating current is carried out. Theoretical bases of creation of a high-precision standard of unit of alternating current are outlined. To build a national standard, the method of comparing the AC current with the equivalent DC current using a precision thermoelectric converter and shunts was chosen. The composition and requirements to the operating conditions of the national standard are determined. Since the storage and reproduction of a unit of alternating current must be realized by comparison with the equivalent direct current, the main source of uncertainty of measurements of this unit is a combination of uncertainties of measurements of thermoelectric comparator Fluke 792A, precision shunts A40, which are part of the standard, output voltage meters measure the electrical resistance to direct current and the output signal of the thermocomparator. According to the results of research work, for the first time in Ukraine the national standard of an alternating current unit was put into operation.
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Крыгин, Сергей Сергеевич, та Юрий Иванович Торба. "Измерение напряженно-деформированного состояния деталей АГТД методом тензометрии". Aerospace technic and technology, № 4sup2 (27 серпня 2021): 44–51. http://dx.doi.org/10.32620/aktt.2021.4sup2.06.
Повний текст джерелаАнотація:
The subject of study in the article is various methods of measuring the stress-strain state of AGTE parts by the tensometry method. Differences were revealed when measuring the stress-strain state of rotor and stator parts, in different frequency ranges (study of static, static-dynamic and dynamic deformations). Methods for compensating or reducing the influence of external factors on the measurement results, such as temperature changes and electromagnetic interference, are indicated. The aim is to develop recommendations for research of AGTE parts in a test bench in a gradient of varying temperatures and in a complex electromagnetic environment of the engine. A review of the sources of inaccuracies, errors and interference arising during preparation for testing and directly during the measurement of the SDS of AGTE parts is performed. The effects of wiring, cabling, grounding and shielding can not only increase the level of errors, but can also negate the advantages of an expensive and extremely reliable electronic part of the system. The advantages and disadvantages of the most common schemes for connecting strain gages, as well as their areas of application are presented. Possible ways to compensate for imaginary deformations at temperatures outside the range of thermal compensation of primary converters. A list of common strain gauge systems with their advantages and disadvantages is given for each type of parts and frequency ranges of measurements. When strain measurement rotary parts to output the signal from the strain gauge to recording equipment used various current collector. The possibility of using wireless interfaces for communication between the primary converter and the recording equipment is also indicated. The described methods are: ways to compensate for imaginary deformations caused by changes in the temperature of the investigated part and connecting wires. Elimination or minimization of electromagnetic interference on the measuring channel. An estimate is given of the total error in measuring the deformation for a particular object under study for the final loading cycle, the specificity of the bench strain gauge path, the errors of the current collector in bench conditions, and others in the process of static strain gauging.
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Pyrozhenko, Ye V., V. V. Sebko, V. G. Zdorenko, N. M. Zashchepkina, and O. M. Markina. "Informative testing method of beer sewage samples for mini-breweries." Archives of Materials Science and Engineering 1, no. 106 (November 1, 2020): 28–41. http://dx.doi.org/10.5604/01.3001.0014.5930.
Повний текст джерелаАнотація:
Purpose: of the article is to investigate the theoretical rules of thermal transformer eddy current converter (TTC) during the preparation of ecological monitoring of brewery sewage samples based on the implementation of contactless two-parameter eddy current method of testing of the specific electrical conductivity λt and the temperature t of the beer sewage sample. It should be noted that this makes it possible to simultaneously prevent the causes of beer sewage samples deviation from the specified environmental safety indicators and to take adjustments. Design/methodology/approach: The theory of TTC operation concerning the electrical and temperature characteristics testing of beer sewage samples has been further developed by implement new universal transformation functions Δφt = f (Gt) and Δφ = f (xt), which relate the normalized difference components of the converter signals to physical and chemical characteristics of the sample. Due to this, it is possible to simultaneously prevent the causes of beer sewage samples deviation from the specified ecological safety indicators and to take appropriate adjustments. Findings: The method of two-parameter measuring test of the specific electrical conductivity λt and the temperature t of the beer sewage sample was developed on the basis of new universal transformation functions. Analysing the numerical data of electrical conductivity λ, TDS and pH at the initial temperature t1 = 15°C, the alkaline nature of beer sewage was determined. Research limitations/implications: The frequency range of the magnetic field f = 80-100 MHz, it is difficult to maintain in laboratory conditions, so the proposed method requires the use of modern high-frequency equipment, the radius of the probe depends on the radius of the primary converter frame. And therefore is quite a complicate to find appropriate tank. Practical implications: is to determine the nature of beer sewage based on the results of electrical and temperature parameters measurements during implementing a two-parameter eddy current method, which allows to prevent the reasons for beer sewage samples deviations from the specified environmental safety measures and to take appropriate adjustments. An important practical result is also the determination of the signal components and the normalized characteristics of the primary eddy current converter with a sample of beer sewage. They allow to calculate, design and create multi-parameter automated devices for measuring test of the physicochemical parameters of beer sewage samples. In turn, as a result of the physicochemical composition analysis of the sample, improving the accuracy of measurements of physicochemical parameters - there is an opportunity to improve and create advanced methods of wastewater purification on a weak electrolytic basis. Originality/value: The article originality is the investigation of the theoretical rules of thermal TTC by implementing a new multi-parameter eddy current method of measuring the specific electrical conductivity λt and the temperature t of the beer sewage sample based on the implementation of universal transformation functions Δφt = f (Gt) and Δφ = f (xt) that relate the converter signals to the physicochemical characteristics of the beer sewage sample, which helps to prevent the causes of the beer sewage samples deviation from the specified environmental safety indicators and take appropriate adjustments.
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Tang, Ge Shi, Li Li, Liang Zeng, Lue Chen, and Lv Zhou. "Measurement and Analysis of the Circuit Delay of CEI System." Applied Mechanics and Materials 128-129 (October 2011): 611–15. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.611.
Повний текст джерелаАнотація:
By using a four port Vector Network Analyzer (VNA), a caesium clock, a time-interval counter and a signal source to measure the delay of CEI system segmentally. Design measuring methods respectively for three segments of the circuit. When measure the delay, it is found that, delay of antenna’s amplifier output port to the input port of down converter (DC) is stable; the fluctuation of DC’s delay is less than 2ns; the cable delay’s standard deviation is stable at 0.1ns; we get a nanosecond accuracy for whole system. The methods of time delay measurement and the design of CEI system will provide a foundation and primary data for future deep space missions.
Дисертації з теми "Primary measuring converter"
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Терещук, Сергій Олександрович. "Первинний вимірювальний перетворювач аналізатору кисню". Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/42045.
Повний текст джерелаАнотація:
Дипломний проект бакалавра на тему «Первинний вимірювальний перетворювач аналізатору кисню», складається з пояснювальної записки у 94 сторінок, 12 рисунків, 3 таблиць, 15 джерел у переліку посилань, креслень деталей та вузлів 3,5 формати А1, що відповідає технічному завданню до дипломного проекту.
У проекті бакалавра на тему «Первинний вимірювальний перетворювач аналізатору кисню» викладено область застосування та характеристику об’єкту аналізу, а саме кисню. У роботі виконано огляд методів та засобів вимірювання концентрації кисню в газових сумішах. Описано методи визначення концентрації кисню у газових сумішах: магнітні, магнітопневматичних, термомагнітних, магнітомеханічний, термомагнітні з внутрішньою та зовнішньою термомагнітною конвекцією.
У дипломній роботі виконано підбір науково-технічної літератури; проведення патентно-інформаційного пошуку; визначення фізико-хімічних характеристик об’єкту аналізу (кисню), аналогів об’єкту проектування і проблемних питань проектування.
Вибір і обґрунтування структурної або функціональної газової схеми аналізатору кисню, проведено необхідні розрахунки. Розроблено функцію перетворення, проведено розрахунки метрологічних, статичних, динамічних характеристик об’єкту проектування. Проведено розрахунки основних функціональних частин, вузлів і елементів об’єкту проектування.
Виконано конструювання основних функціональних частин, вузлів і елементів виробу, розроблено креслення загального виду і складального креслення основних частин і вузлів первинного вимірювального перетворювача концентрації кисню у газових сумішах. Проведено уточнювальні розрахунки, необхідність в яких виникла в процесі розробки конструкції виробу.Bachelor's thesis project on "Primary measuring transducer of oxygen analyzer", consists of an explanatory note of 94 pages, 12 figures, 3 tables, 15 sources in the list of references, drawings of parts and assemblies 3.5 A1 format, which corresponds to the terms of reference for the thesis. The bachelor's project on "Primary Oxygen Analyzer Measuring Converter" sets out the scope and characteristics of the object of analysis, namely oxygen. The paper reviews methods and means of measuring the oxygen concentration in gas mixtures. Methods for determining the oxygen concentration in gas mixtures are described: magnetic, magnetopneumatic, thermomagnetic, magnetomechanical, thermomagnetic with internal and external thermomagnetic convection. In the diploma work the selection of scientific and technical literature is executed; conducting patent information search; determination of physical and chemical characteristics of the object of analysis (oxygen), analogues of the object of design and problematic issues of design. Selection and substantiation of the structural or functional gas scheme of the oxygen analyzer, the necessary calculations are performed. The transformation function is developed, calculations of metrological, static, dynamic characteristics of the design object are carried out. The calculations of the main functional parts, units and elements of the design object are performed. The design of the main functional parts, assemblies and elements of the product is performed, the drawing of the general view and the assembly drawing of the main parts and assemblies of the primary measuring transducer of oxygen concentration in gas mixtures are developed. Clarifying calculations were carried out, the need for which arose in the process of product design.
Частини книг з теми "Primary measuring converter"
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Perederko, Anatoly. "Correction of the Temperature Component of Error of Piezoelectric Acceleration Sensor." In Handbook of Research on Artificial Intelligence Applications in the Aviation and Aerospace Industries, 263–78. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1415-3.ch011.
Повний текст джерелаАнотація:
In the aviation and aerospace industries, systems of artificial intelligence are being intensively implemented. For their effective functioning, it is necessary to provide reliable primary information. Information is collected by primary converters. In various systems of aviation technology, piezoelectric accelerometers are widely used as primary transducers. In particular, they are part of inertial navigation systems. These systems do not need external sources of information and are not affected by external interference. Therefore, they are widely used in aircraft for various purposes. These accelerometers are also used in other aircraft systems. In systems for monitoring the operation of gas turbine engines, systems for registering overloads. However, in conditions of high-temperature differences, shocks, vibrations, and significant accelerations, piezoelectric transducers have inherent flaws that affect the linearity and accuracy in measuring these values. Especially piezoelectric transducers are critical to extreme temperatures.
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Alatrista-Salas, Hugo, Manuel Rodriguez-López, and Miguel Nunez-del-Prado. "Resilience of Urban Infrastructure in Latin American Cities." In Advances in Logistics, Operations, and Management Science, 360–78. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8160-4.ch019.
Повний текст джерелаАнотація:
Resilience is the capacity of a society or infrastructure to resist, adapt, and recover after being impacted by an extreme event. In this chapter, the authors focus on measuring how much the road infrastructure is able to withstand the appearance of extreme events. An extreme event will be represented by an intentional (e.g., perpetrated attacks) or unintentional (e.g., as result of climate extreme event) damage on the routes or intersections of the road network within a city. To do this, the authors measure the primary characteristics of urban networks in order to understand their morphology (i.e., the way in which they were constructed). Then, they evaluated the resistance capacity of different points of the road networks with three types of attacks: random, directed, and localized. The first results of this study show the fragility of some roads and intersections before the appearance of extreme phenomena. These results can be exploited by those in charge of public management and then converted into policies.
Тези доповідей конференцій з теми "Primary measuring converter"
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Skliarov, Vladimir, Konstantin Muentean, and Eugen Timofeev. "Calibration of primary measuring converter by using of modeling and experimental evaluation of the initial data." In 18th International Congress of Metrology, edited by Cosimi Corletto. Les Ulis, France: EDP Sciences, 2017. http://dx.doi.org/10.1051/metrology/201708005.
Повний текст джерела
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Osadchuk, Alexander V., Vladimir S. Osadchuk, Iaroslav O. Osadchuk, Volodymyr Bogachuk, Olena O. Seletska, Mariusz Duk, and Saule Smailova. "Development and research of a radio measuring device with a frequency output signal based on a pyroelectric primary converter." In Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2019, edited by Ryszard S. Romaniuk and Maciej Linczuk. SPIE, 2019. http://dx.doi.org/10.1117/12.2536907.
Повний текст джерела
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Zelensky, S. А., and M. S. Stepanov. "MEASURING SYSTEM FOR MONITORING GRAIN TEMPERATURE DURING STORAGE." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS. DSTU-PRINT, 2020. http://dx.doi.org/10.23947/interagro.2020.1.116-118.
Повний текст джерелаАнотація:
In science and technology, today various sensors of electrical and non-electrical quantities are used. The article provides a brief overview of the primary converters. One of the devices for nondestructive testing of thermophysical properties for determining the characteristics of agricultural objects in production is presented.
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Pugh, Daniel, Philip Bowen, Andrew Crayford, Richard Marsh, Jon Runyon, Steven Morris, and Anthony Giles. "Catalytic Influence of Water Vapor on Lean Blowoff and NOx Reduction for Pressurised Swirling Syngas Flames." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-64609.
Повний текст джерелаАнотація:
It has become increasingly cost-effective for the steel industry to invest in the capture of heavily carbonaceous BOF (Basic Oxygen Furnace) or converter gas, and use it to support the intensive energy demands of the integrated facility, or for surplus energy conversion in power plants. As industry strives for greater efficiency via ever more complex technologies, increased attention is being paid to investigate the complex behavior of by-product syngases. Recent studies have described and evidenced the enhancement of fundamental combustion parameters such as laminar flame speed due to the catalytic influence of H2O on heavily carbonaceous syngas mixtures. Direct formation of CO2 from CO is slow due to its high activation energy, and the presence of disassociated radical hydrogen facilitates chain branching species (such as OH), changing the dominant path for oxidation. The observed catalytic effect is non-monotonic, with the reduction in flame temperature eventually prevailing, and overall reaction rate quenched. The potential benefits of changes in water loading are explored in terms of delayed lean blowoff, and primary emission reduction in a premixed turbulent swirling flame, scaled for practical relevance at conditions of elevated temperature (423 K) and pressure (0.1–0.3 MPa). Chemical kinetic models are used initially to characterize the influence that H2O has on the burning characteristics of the fuel blend employed, modelling laminar flame speed and extinction strain rate across an experimental range with H2O vapor fraction increased to eventually diminish the catalytic effect. These modelled predictions are used as a foundation to investigate the experimental flame. OH* chemiluminescence and OH planar laser induced fluorescence (PLIF) are employed as optical diagnostic techniques to analyze changes in heat release structure resulting from the experimental variation in water loading. A comparison is made with a CH4/air flame and changes in lean blow off stability limits are quantified, measuring the incremental increase in air flow and again compared against chemical models. The compound benefit of CO and NOx reduction is quantified also, with production first decreasing due to the thermal effect of H2O addition from a reduction in flame temperature, coupled with the potential for further reduction from the change in lean stability limit. Power law correlations have been derived for change in pressure, and equivalent water loading. Hence, the catalytic effect of H2O on reaction pathways and reaction rate predicted and observed for laminar flames, are compared against the challenging environment of turbulent, swirl-stabilized flames at elevated temperature and pressure, characteristic of piratical systems.
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Altstadt, Eberhard, Carsten Beckert, Hartwig Freiesleben, Vladimir Galindo, Eckart Grosse, Arnd Junghans, Ba¨rbel Naumann, and Frank-Peter Weiss. "Design of a Photoneutron Source for Time-of-Flight Experiments at the Radiation Source ELBE." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49456.
Повний текст джерелаАнотація:
The new radiation source ELBE at Research Center Rossendorf uses the high brilliance electron beam from a superconducting LINAC to produce various secondary beams. Electron beam intensities of up to 1 mA at energies between 12 MeV and 40 MeV can be delivered with a wide variability in the electron pulse structure. The maximum pulse frequency is 13 MHz with a pulse width less than 10 ps. The small emittance of the electron beam permits the irradiation of very small volumes. These main beam parameters led to the idea to convert the intense picosecond electron pulses into sub-ns neutron pulses by stopping the electrons in a heavy (high atomic number) radiator and to produce neutrons by bremsstrahlung photons through (γ,n)-reactions. In order to enable measurements of energy resolved neutron cross sections like (n,p), (n,α) and (n,f) with a time-of-flight arrangement with a short flight path of only a few meters, it is necessary to keep the volume of the radiator for neutron production as small as possible to avoid multiple scattering of the emerging neutrons which would broaden the neutron pulses. It is the primary physics objective of this neutron source to determine neutron cross sections firstly for construction materials of fusion and fission reactors, for which it is important to select radiation hard materials, and secondly for the handling of waste from such reactors, especially in order to find processes which transmute long-lived radioactive nuclides into short-lived and finally stable ones. In addition, the distribution of fragments can be analyzed which are produced by neutron-induced transmutation of long-lived radioactive nuclides. Furthermore experiments can be performed which address problems of nuclear astrophysics. The energy deposition of the electron beam in the small neutron radiator is that high that any solid material would melt. Therefore, the neutron radiator consists of liquid lead flowing through a channel of 11.2×11.2 mm2 cross section. From the thermal and mechanical point of view molybdenum turned out to be the most suited channel wall (thickness 0.5 mm) material. Depending on the electron energy and current up to 20 kW power will be deposited into a radiator volume of 3 cm3. This heating power is removed through the heat exchanger in the liquid lead circuit. Typical flow velocities of the lead are in the range of 2 m/s in the radiator section. The electrons that are not stopped in the radiator and the secondary radiation are dumped in an aluminum beam dump. To reduce the radiation back-ground in the measuring direction, the neutrons are decoupled from the radiator at an angle of 90° with respect to the impinging electrons. Particle transport calculations were carried out using the Monte Carlo codes MCNP and FLUKA. These calculations predict a neutron source strength of 7.88·1012 and 2.67·1013 n/s for electron energies between 20 and 40 MeV. At the measuring place 362 cm away from the radiator, neutron fluxes of 1.7·107 n/(cm2 s) will be obtained. The mentioned time-of-flight distance allows for an energy resolution better than 1%. The maximum usable neutron energy is about 7 MeV.
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Bezeaud, A., та M. C. Guillin. "FUNCTIONAL CHARACTERIZATION OF HUMAN β-THROMBIN". У XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644665.
Повний текст джерелаАнотація:
Autolysis or tryptic hydrolysis converts β-thrombin (α-T) t β-thrombin ( β -T), and subsequently β-T to y-thrombin (γ-T). Human β-T differs from native α-T by the loss of a unique ll-re-sidues peptide arising from the B chain. Unlike its bovine counterpart, human β-Tisa transient intermediate and its enzymatic properties had not yet been investigated using purified materiaL After 3 min incubation of human β-T with trypsin-sepharose, the resulting β-T was separated from α- and γ-T by chromatography on Biorex 70 with a gradient from 10 mM to 500 mM phosphate at pH 8. No major differences were found between human α- and β-T regarding the kinetic parameters (Km, kcat, kcat/Km) on S 2238, nor the rate of inactivation by TLCK. In contrast, inhibition of β-T by DFP was slower (k = 426 ±[; 10.8 M-1 min−1) compared to α-T (764.5 ± 19.5 M−11min−1and the inhibition constant for benzami-dine was higher with β-T (Ki = 11.2 ± x00B1;.2 10−4 M) compared to α-T (Ki = 2.86± 0,06 10−4 M). The drastic reduction in the clotting activity of β-T (25 u mg−1 versus 3000 u mg−1 for α-T) was further explored by measuring the affinity of β-T for fibrinogen and fibrin. Human fibrinogen was used as a competitor in the inactivation of thrombin by DFP : 10 μM fibrinogen prevented the inhibition of α-T by DFP but failed to modify the inactivation rate of α-T. Binding of thrombin to fibrin was studied using fibrin monomers covalently linked to sepharose 4B, equilibrated in 50mM Tris, pH 7.5, 50 mM NaCl : β -T did not bind to the resin, whereas α-T was retained and eluted upon application of a NaCl gradient.In conclusion, the loss of the peptide extending from lie (63) to Arg (73) in the thrombin B chain is responsiblefor multiple defects in thrombin enzymatic activity. Although, the three active site residues Ser (205), His (43), Asp (99) remain in an active configuration, subtle changes are induced in the microenvironment of the catalytic Ser (205), and in particular, in the primary binding pocket. In addition, the results presented in this study indicate thatthe loss of clotting activity is mainly the result of a decreased affinity for fibrinogen and fibrin, suggesting that the structural changesaffect both the fibrinopeptide groove and the anionic binding site involved in fibrinogen/fibrin recognition.
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Juranic, Tomislav, Ivan Meandzija, and Ivo Steiner. "H2S and Mercaptane in Gas Production: Practical Operating Experience." In ASME 2001 Engineering Technology Conference on Energy. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/etce2001-17084.
Повний текст джерелаАнотація:
Abstract INA-Naftaplin has been utilizing the LO-CAT® process in Croatia for protection of ambient air against H2S pollution at its Gas Treatment Plant Molve III already for seven years. This separation unit, incorporated into the gas treatment plant has been erected exclusively for the protection of ambient air against harmful effect of H2S. The unit is treating H2S+CO2, which is being removed from natural gas by an upstream amine process, under conditions of low H2S content and low pressure of gas. Catalytic oxidation is being used to convert H2S to elementary sulfur, and the emission concentration was decreased from 580 ppm to less than 30 ppm. The practice revealed a series of delicate situations: plugging of internals, solution filtering and achievement of required 60 wt% sulfur concentration, disposal of produced sulfur sludge and others. The Institute for Medical Research Zagreb has performed the ambient air quality monitoring, within the scope of its contract for annual base monitoring. H2S imission values were under 5 μg/m3. The continuous control of working area is achieved by twenty-four H2S sensors, and results obtained to this date have always been below allowable limits. The practical experience has revealed that the LO-CAT® desulfurization unit has fulfiled its purpose and existing environmental criteria till 1997, along with significant cost, primarily for power and chemicals. The actual Croatian Directive on TLV of pollutants in the waste gas requires H2S concentration of 3.5 ppmv max. and RSH concentration of 20 mg/m3 max. Now the GTP Molve and Ethane Recovery Plant have emission of H2S and mercaptane above the permissible limit value, which have to be solved until the year 2004. To meet the strict legal requirements, certain upgrading is to be undertaken. This capital investment requires a large financial expenditure of up to 5 million USD, and up to 1 million USD/year for operating cost for both plants. For process improvement a continuous monitoring system has to be solved also. In that respect, measuring of H2S+RSH emission is in accordance to ASTM D-4084-82 and ASTM D-23 85-81 methods. Periodical control by gas tube detector system could contribute to the most reliable and efficient monitoring system of the two most important natural gas plants in Croatia.