The consumption-based carbon emissions effects of renewable energy and total factor productivity: The evidence from natural gas exporters

This study first time explores the impact of total factor productivity, renewable energy, exports, imports, and income on carbon emissions in the Gas Exporting Countries Forum (GECF) nations. To ensure that the results are sound and policy insights are well-grounded, three main issues of panel data – cross-sectional dependency, heterogeneity, and nonstationarity – are addressed using cutting-edge methods. Moreover, a theoretically justified framework is employed, offering advantages such as considering a broad set of factors, which are actionable from a climate policy perspective, with dual benefits of emissions reduction and supporting clean growth. We find that total factor productivity, renewable energy, and exports reduce carbon emissions, while income and imports have an increasing effect. Policymakers in GECF countries may consider implementing measures to support technological advancements, efficiency improvements, increased use of renewable energy, expanded exports, and lowered imports. They can reduce emissions while promoting sustainable economic growth

Numerical study of stress-strain state of pelvis at the proximal femur rotation osteotomy

© Sachenkov O.A., Hasanov R.F., Andreev P.S., Konoplev Yu.G., 2016.The relevance of this study is dictated by the high frequency of occurrence of the disease. Among all hip diseases, Legg-Calvé-Perthes disease takes 25-30 % of diseases in childhood. There are no certain and founded recommendations for surgering in general and rotary flexion osteotomies in particular. The study is to determine the stress-strain state of the joint at different directions and magnitudes of the rotation angle. Calculations were carried out by using computer modelling of the hip joint based on localization of degenerative process and the severity of the degeneration of epiphysis in children and adolescents with Legg-Calvé-Perthes diseases. Numerical studies were performed using the finite element method in Nastran Siemens NX. The paper took into account the effect of the following muscles: mm. piriformis, rectus femoris, iliopsoas, obturatorius internus, gluteus minimus, medius et maximus. The calculations allow us to determine the forces produced in the muscles, reactive power and reactive torque acting in the joint at different rotation angles (these values are relevant for assessing the stiffness of external fixation device). The maximum shear stresses and Mises stresses have been identified in the acetabulum and the proximal part of the femur. Evaluation of strength was determined by the maximum shear stresses. So, in the acetabulum with a rotation of 25° forward and rotation of 35° back, the greatest value of maximum shear stress exceeds 1.7 MPa; at the rotation of more than 30° back, the value of similar stress exceeds 6.4 MPa; at forward rotation to 50°, the highest maximum shear stresses reach a value of 5.0 MPa. Thus, when the rotation back to the angle over 30°, maximum shear stresses in the joint region are into the lower critical value, at 35,° they are situated in the upper region of the critical values. When considering forward rotation angle over 25°, maximum shear stresses are into the lower region of the critical values, crossing through the upper region of the critical values at rotation to 50° does not occur

Determination of muscle effort at the proximal femur rotation osteotomy

© Published under licence by IOP Publishing Ltd.The paper formulates the problem of biomechanics of a new method for treatment of Legg-Calve-Perthes disease. Numerical calculations of the rotational flexion osteotomy have been carried out for a constructed mathematical model of the hip joint, taking into account the main set of muscles. The work presents the results of the calculations and their analysis. The results have been compared with the clinical data. The calculations of the reactive forces arising in the acetabulum and the proximal part of the femur allowed us to reveal that this reactive force changes both in value and direction. These data may be useful for assessing the stiffness of an external fixation device used in orthopedic intervention and for evaluating the compression in the joint

Determination of muscle effort at the proximal femur rotation osteotomy

© Published under licence by IOP Publishing Ltd.The paper formulates the problem of biomechanics of a new method for treatment of Legg-Calve-Perthes disease. Numerical calculations of the rotational flexion osteotomy have been carried out for a constructed mathematical model of the hip joint, taking into account the main set of muscles. The work presents the results of the calculations and their analysis. The results have been compared with the clinical data. The calculations of the reactive forces arising in the acetabulum and the proximal part of the femur allowed us to reveal that this reactive force changes both in value and direction. These data may be useful for assessing the stiffness of an external fixation device used in orthopedic intervention and for evaluating the compression in the joint

Frequency division sensor signal by controlled and interfering parameters

Objective. The aim of the study is the possibility of obtaining the impedance of the controlled and interfering parameters using the example of a capacitor sensor. Method. The study is based on the determination of the analytical relationship between the change in the impedance of the sensor and the frequency of the current in which the capacitance of the capacitor is excited. Result. Having determined the resistance of individual circuit elements, you can find the impedance of the equivalent circuit at any fixed frequency. An equation for the impedance of the sensor is obtained, reflecting the dependence of the output signal on the change in both the controlled humidity and the interfering parameter - the dielectric constant of oil at any frequency in the studied range. The existence of the frequency parameter for the separation of information contained in the output signal of the measuring circuit has been proved. Conclusion. If the parametric separation of the signal is possible, the output value of the sensor can be automatically corrected for the change in the dielectric constant of the "dry" oil, and continuous measurement of the controlled moisture can be carried out

Использование особенностей фотоупругого эффекта для измерения параметров лазерного излучения

The article discusses the photo-elastic effect features in acousto-optic processors for processing pulse signals on the time axis. The photo-elastic interaction in these devices is divided into two areas. In the first area, the input pulse duration is longer than the time of intersecting the optical beam by the elastic wave packet. This particular area is widely used in the practical applications of these processors, where it is a priori assumed that the input pulse duration is longer than the time for the elastic wave packet to intersect the optical beam.In the second area, the input pulse duration is less than the time for the optical beam to be intersected by the elastic wave packet. The objective of this work is to study the photo-elastic effect features in this area. It was established that in this area the pulse duration at the processor output is equal to the time for the optical beam to be intersected by the elastic wave packet and does not depend on the input pulse duration, which is permissible in some cases (for example, in radar pulse existence rather than its duration is recorded). It is shown that in the second area, the output pulse is formed as the sum of three terms. The first term corresponds to the elastic wave packet entering the optical beam. The second term corresponds to the elastic wave packet advancement in the optical beam aperture, and the third one keeps with the elastic wave packet leaving the aperture of the optical beam. The corresponding equations for calculating the pulse at the device output are obtained. The numerical calculations have proved the provisions and patterns established. The numerical modeling results were tested experimentally using a prototype of an acousto-optic processor with direct detection. The analysed results of theoretical and experimental studies unequivocally confirmed that the obtained formulas, formulated statements, and established provisions can be used to expand the functionality of acousto-optic processors, both with direct detection and of heterodyne type. It is shown that with a significant decrease in the input pulse duration relative to the time during which the optical beam is intersected by the elastic wave packet, the latter is converted into a scanning line and can be used to measure the geometric and energy characteristics of the quasi-coherent light.В статье обсуждаются особенности фотоупругого эффекта в акустооптических процессорах для обработки импульсных сигналов на временной оси. Фотоупругое взаимодействие в этих устройствах разделено на две области. В первой области длительность входного импульса больше времени пересечения оптического пучка упругим волновым пакетом. Именно эта область широко используется в практических применениях названных процессоров, где априори предполагают, что длительность входного импульса больше времени пересечения оптического пучка упругим волновым пакетом.Во второй области длительность входного импульса меньше времени пересечения оптического пучка упругим волновым пакетом. Исследование особенностей фотоупругого эффекта в этой области является целью данной работы. Установлено, что в этой области длительность импульса на выходе процессора равна времени пересечения оптического пучка упругим волновым пакетом и не зависит от длительности входного импульса, что в некоторых случаях допустимо (например, в радиолокации фиксируется факт наличия импульса, а не его длительность). Показано, что во второй области выходной импульс формируется как сумма трех слагаемых. Первое слагаемое соответствует процессу вхождения упругого волнового пакета в оптический пучок, вторая – процессу продвижения упругого волнового пакета в апертуре оптического пучка, а третья - процессу выхода упругого волнового пакета из апертуры оптического пучка. Получены соответствующие уравнения для вычисления импульса на выходе устройства. Установленные положения и закономерности подтверждены численными расчетами. Результаты численного моделирования апробированы экспериментально на макете акустооптического процессора с прямым детектированием. Анализ результатов теоретических и экспериментальных исследований однозначно подтвердил, что полученные формулы, сформулированные утверждения и установленные положения могут быть использованы для расширения функциональных возможностей акустооптических процессоров, как с прямым детектированием, так и гетеродинного типа. Показано, что при значительном уменьшении длительности входного импульса по отношению ко времени пересечения оптического пучка упругим волновым пакетом, последний преобразуется в сканирующую линию и может быть использован для измерения геометрических и энергетических характеристик квазикогерентного света

Акустооптический формирователь светового импульса для измерения параметров фотоприемников

The paper emphasizes that intensive utilization of the optical range increases the need for the development of new optoelectronic devices. Accordingly, there is a growth in the need for effective methods and tools to study photoelectric properties of semiconductor materials, including photo-detectors.In the paper we have analyzed the well-known methods and tools for measuring the photo-detector parameters, defined the restrictions in their applications, and proved that it is relevant to create a measuring system, the parameters of which are easily adapted to the study of photoelectric characteristics of a wide range of semiconductor materials, including photo-detectors.The scheme and principle of operation of the acousto-optic processor and the features of the photo-elastic effect are discussed, and it is proved that they can be used to form a light pulse of required duration and power. The expressions obtained for calculating the response at the acousto-optic processor output enable us to estimate separately the effects of time of crossing the optical beam by the elastic wave packet and the photo-detector inertia.The capability to determine the time of crossing the optical beam by the elastic wave packet and taking it into account as a device error has been substantiated. The proposed formulas have been tested and by numerical analysis based on the datasheet specifications of the FD-24K photodiode, the effectiveness of the obtained expressions has been convincingly proven.The inertia parameters of a particular sample of the FD-24K photodiode are experimentally studied. The emphasis is upon measuring the rise time of the transient response of the object under study. The exact rise time value of the transient response of the experimental FD-24K sample was approximately 7 μs, which is less than that indicated (≤10 μs) in the product certificate. In real life, such a measurement is necessary when selecting the photodiode pairs with identical parameters.By comparing the results of numerical analysis and experimental studies, it has been convincingly proven that the features of the photo-elastic effect can be used to construct a light pulse shaper with the required parameters.Отмечено, что интенсивное освоение оптического диапазона усиливает необходимость разработки новых оптоэлектронных приборов. Соответственно возрастает потребность в эффективных методах и средствах исследования фотоэлектрических свойств полупроводниковых материалов, в том числе фотоприемников.Проанализированы известные методы и средства измерения параметров фотоприемников, указаны ограничения в их применениях и доказана актуальность создания измерительной системы, параметры которого легко адаптируются к исследованию фотоэлектрических характеристик широкого спектра полупроводниковых материалов, в том числе фотоприемников.Рассмотрена схема и принцип функционирования акустооптического процессора, обсуждены особенности фотоупругого эффекта и доказана возможность их использования для формирования светового импульса с нужной длительностью и мощностью. Получены выражения для вычисления отклика на выходе акустооптического процессора, позволяющие в отдельности оценивать влияния времени пересечения оптического пучка упругим волновым пакетом и инерционности фотоприемника. Обоснована возможность определения времени пересечения оптического пучка упругим волновым пакетом и учета его как приборную погрешность. Предложенные формулы апробированы и путем численного анализа на основе паспортных данных фотодиода ФД-24К убедительно доказано действенность полученных выражений.Экспериментально исследованы параметры инерционности конкретного образца фотодиода ФД-24К. Основное внимание уделено на измерение времени нарастания переходной характеристики объекта исследования. Точное значение времени нарастания переходной характеристики экспериментального образца ФД-24К составило, примерно, 7 мкс, что меньше указанного (≤10 мкс) в паспорте изделия. На практике такое измерение необходимо при подборе фотодиодных пар с идентичными параметрами.Путем сопоставления результатов численного анализа и экспериментальных исследований убедительно доказано, что особенности фотоупругого эффекта могут быть использованы для построения формирователя световых импульсов с необходимыми параметрами

The Development of a Piezoelectric Defect Detection Device Through Mathematical Modeling Applied to Polymer Composite Materials

In this research article, the focus is on examining the strength characteristics of polymer composite materials under various stress states. The investigation into the material dissolution process is conducted in two distinct stages. Initially, the article employs a criterion approach to derive explicit formulas for the latent decay time (incubation period) of materials, considering singular, exponential and Abelian kernels of the damage operator. In the subsequent stage, the classical strength condition is applied to establish a Volterra type integral equation, which characterizes the damage process for hereditary materials. These resulting differential equations are then solved with appropriate initial conditions. The study utilizes the obtained results to create time- dependent graphs of the damage parameter and performs comparisons. A piezoelectric defect detection device for polymer composite materials has been proposed through the application of mathematical modeling

Learning Environments in the 21st Century: A Mapping of the Literature

Education has been transformed by significant breakthroughs in AI, mobile internet, cloud computing and Big Data technologies. More personalized educational settings are developed by increasingly integrating contemporary learning environments with new technologies. However, few examples of executed AI enabled learning interventions have been identified. Therefore, a mapping of literature on AI enabled learning systems was done. 121 studies published in the last five years were analyzed. This paper presents a discussion regarding on what mainly AI enabled contemporary learning environments are designed to achieve. The major contribution of the study is bringing awareness to researchers and system developers on the purposes of AI enabled contemporary learning environments. This review will act as a guide for future studies on how to better design AI enabled learning environments.acceptedVersio