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Данная работа посвящена обзору энергетических установок, применяемые на автомобильном транспорте, сравнение параметров при различных исходных величинах, оптимизационные расчеты основных элементов, разработка принципов регулирования и управления автономным автомобильным источником энергии., This work is devoted to the review of power plants used in automobile transport, comparison of parameters at different initial values, optimization calculations of basic elements, development of principles of regulation and management of autonomous automotive energy source.

Cloud Computing can be described as any where any time storage and it is able to provide on demand services like server, storage, software etc. to the users over internet. Cloud consists of multiple virtual machines which includes several facilities like computation and storage. The foremost aim of cloud computing is to provide systematic and well regulated access to distant and geographical resources. The efficient discharge of task scheduling computing is one of the primary factors. This paper deals with the subject of dynamic load balancing for task scheduling in cloud environment. Satisfactory results can be obtained by implementing the proposed algorithm by considering distribution of tasks on the basis of types (nature), processing efficiency and load efficiency factor. In this paper, algorithm has been implemented by taking into account cloud VM groups, configuration and nature of tasks which determines that resources have been utilized efficiently. The result has been compared and shows better results in terms of average turnaround time, average response time, average waiting time and cost efficiency ratio than existing load balancing algorithms [1, 2].

В данной работе рассмотрены вопросы влияния совместимости многокомпонентных систем на свойства строительных композитов. Установлены зависимости изменения физико-механических характеристик многокомпонентных систем от таких количественных показателей, как вид вяжущего, вид минерального порошка и их соотношения. Проведена оценка степени эффективности минеральных добавок-порошков с использованием критерия механической активности минеральных тонкодисперсных компонентов. Доказано, что применение минеральных порошков различной природы с удельной поверхностью в пределах от 300 до 700 м2/кг позволяет экономить цементную составляющую многокомпонентных систем, не в ущерб свойств, при этом коэффициент эффективности от их использования изменяется от 0,8 до 1,9. Результаты, представленные в настоящей статье, получены в рамках исследований по реализации научного проекта № 05. 607.21.0320. "Разработка технологии новых строительных композитов на бесклинкерных вяжущих щелочной активации с использованием некондиционного природного и вторичного сырья" получившего поддержку Федеральной целевой программы «Исследования и разработки по приоритетным направлениям развития научно-технологического комплекса России на 2014-2020 годы». Уникальный идентификатор соглашения RFMTFI60719X0320., This paper discusses the influence of the compatibility of multicomponent systems on the properties of building composites. Dependences of the change in the physical and mechanical characteristics of multicomponent systems on such quantitative indicators as the type of binder, the type of mineral powder and their ratio have been established. The degree of efficiency of mineral additives-powders was evaluated using the criterion of mechanical activity of fine mineral components. It has been proven that the use of mineral powders of various nature with a specific surface in the range from 300 to 700 m2 / kg allows saving the cement component of multicomponent systems, without compromising properties, while the efficiency coefficient from their use varies from 0.8 to 1.9 This work was supported by the project No. 05. 607.21.0320. "Development of innovative structural composite materials based on clinkerless binders of alkaline activation using off-grade natural and secondary raw stuff" in the frame of Federal target program "Studies and developments in the prioritized fields of development of R&D complex of Russia for the years 2014-2020". Unique identifier: RFMTFI60719X0320., Вестник Комплексного научно-исследовательского института им. Х.И. Ибрагимова РАН, Выпуск 3 (3) 2020

В данной работе рассмотрены закономерности протекания процессов структурообразования в композитах с использованием высокодисперсных порошков различной природы, требующих проведения систематизации всех факторов, влияющих на формирование структуры, на кинетику набора свойств. В результате проведения системного анализа многокомпонентных цементных систем, являющихся объектами управления, можно выделить основные факторы, оказывающие влияние на структуру и свойства многокомпонентных цементных систем. Результаты, представленные в настоящей статье, получены в рамках исследований по реализации научного проекта № 05. 607.21.0320. "Разработка технологии новых строительных композитов на бесклинкерных вяжущих щелочной активации с использованием некондиционного природного и вторичного сырья" получившего поддержку Федеральной целевой программы «Исследования и разработки по приоритетным направлениям развития научно-технологического комплекса России на 2014-2020 годы». Уникальный идентификатор соглашения RFMTFI60719X0320, In this work, the regularities of the course of processes of structure formation in composites using highly dispersed powders of various natures, requiring the systematization of all factors affecting the formation of the structure, on the kinetics of a set of properties, are considered. As a result of the system analysis of multicomponent cement systems, which are control objects, it is possible to identify the main factors that affect the structure and properties of multicomponent cement systems. This work was supported by the project No. 05. 607.21.0320. "Development of innovative structural composite materials based on clinkerless binders of alkaline activation using off-grade natural and secondary raw stuff" in the frame of Federal target program "Studies and developments in the prioritized fields of development of R&D complex of Russia for the years 2014-2020". Unique identifier: RFMTFI60719X0320., Вестник Комплексного научно-исследовательского института им. Х.И. Ибрагимова РАН, Выпуск 3 (3) 2020

Solar energy market is still growing in Morocco and in other countries around the world. The development and deployment of any solar project require a prefeasibility study before the establishment of the plant. The most important parameters influencing the site selection or the project feasibility are solar radiation and the climatic conditions. Soiling is a limiting efficiency factor that drastically affect the optical and the electrical performances of the solar plants. The objective of the current study is to evaluate and compare the soiling impact, from an optical point of view, on both PV and CSP technologies by investigating the reflectance and transmittance drop of glass and mirror samples exposed at Green Energy Park research facility (Morocco) during the dry period of the year. The results show that the effect of soiling is very important in the dry period of the year, it can reach up to 35% of soiling loss after only one week for the mirror samples. For the glass samples, the drop can reach up to 12%. Besides, it has been found that the CSP mirrors are three times more affected by soiling than PV glass samples. Keywords: Hybrid CSP/PV plant, Soiling, Optical efficiency, Outdoor exposition, Mid-south of Morocco

Typical coal processing wastes can be used as fuel, though of a low rank, because they contain a combustible component – coal particles, usually less than 100 μm in size. Waste-to-energy combustion is a promising way to solve a number of environmental, economic, and energy problems: low-rank coals, coal processing and petroleum refining wastes are involved in the energy sector as components of coal-water slurries with or without petrochemicals. In this research, we used state-of-the-art non-contact optical measurement techniques to experimentally study the atomization behavior of high-potential liquid fuels. The fuels were based water and a typical coal processing waste – filter cake – in the form of particles less than 100 μm in size. Following the experiments, we have established the variation ranges of the jet characteristics and the effect of spraying conditions thereon for each composition under study. For each characteristics recorded, dimensionless integral criteria have been calculated illustrating the atomization behavior. Finally, we have determined the values of the spraying efficiency factor for all the slurries under study. These values make it possible to predict the fuel atomization and ignition behavior as well as compare the fuel compositions and choose the one for specific operating conditions.

A first order dynamic model was developed and validated via experimental data for a PVT retrofitted collector. The model utilizes the analytic solution of collector’s energy balance equation, with the purpose to estimate the absorber mean temperature via an iterative process. All collector’s crucial parameters like the overall heat loss coefficient and collector efficiency factor are estimated for every simulation time-step, while PVT’s optical efficiency is calculated analytically via the principal laws of optics. The simulation results fount to be in good agreement with experimental data. In more details, the RMS deviation for collector’s outlet temperature was estimated to 0.66% for stable weather conditions and to 4.22% for extremely transient conditions with sporadic showers. Also, the discrepancy for power generation fount to be 5.05% and 14.91% for stable and transient weather conditions respectively. Moreover, for unstable weather without rain but with abrupt changes on flow-rate, the model found at sufficient accuracy with RMS deviation of 2.06% for water outlet temperature and 4.15% for power generation. Finally, by considering the absorber’s heat inertia on the collector energy balance equation, a positive contribution on model’s accuracy can be obtained, contrary to the steady-state version.

Solar thermal collectors including hybrid photovoltaic-thermal (PV-T) collectors can be certified in accordance with the ISO 9806 standard for an assessment of their reliability and thermal performance. The ISO 9806 standard relies on the Perers model for the latter though the model does not differentiate between hybrid (fluid circulation and electricity generation) and non-hybrid (no electricity generation) operation of PV-T collectors. The present communication proposes an extension of the Perers model explicitly accounting for the effective absorption factor reduction caused by electricity generation in PV-T collectors under maximum power point (MPP) operation, and discusses its suitability for parameter estimation via multi-linear regression (MLR). The solution devised assumes a linear MPP cell efficiency temperature dependence and employs the collector efficiency factor construct on which the original Perers model already implicitly relies, thus avoiding the need to measure additional quantities while remaining compatible with MLR. In doing so, more detailed thermal performance modelling of PV-T collectors is possible than with the standard Perers model, with minimal additional effort and while retaining the original’s modularity. The extended model’s added relevance is nonetheless predicted to be positively correlated with the thermal and electrical performance levels and the cell efficiency temperature dependence.

An analytical model for the parabolic trough collector (PTC) having its absorber tubes fitted with serrated twisted tape inserts using therminol VP-1 as working fluid for high temperature applications in solar thermal electric power system was developed taking radiative terms into account. The model takes radiative terms into account, for the development of the mathematical expressions for collector efficiency factor, collector heat removal factor, outlet fluid temperature and thermal efficiency. A computer program in C++ language, based on mathematical models was developed, to estimate the temperature rise of fluid for evaluation of the performance of PTC under specified conditions. For numerical simulations, three different twist ratios, x = 1,2.5,4 and mass flow rates ranging from 0.06 kg/s to 0.16 kg/s (3000 ≤ Re ≤ 9000) and dimensionless insolation, Ψ(t) = 0.2 to 1.0 are used. This study demonstrates that twisted tape insert shows great promise for enhancing the performance of the PTC. The maximum value of outlet fluid temperature, useful heat gain and thermal efficiency are 452.52 K, 17711 W and 79.22 %, respectively for x = 1, Ψ(t) = 1.0 and mass flow rate of 0.16 kg/s.

Carbon fiber reinforced polymer (CFRP) composite external wrapping has become an increasing popular strengthening and confining method for deteriorated or damaged concrete structures. The benefits are high strength-to-weight ratio, corrosion resistance, economy of labor and space savings. This study involved a non-linear theoretical modeling of axially loaded concrete columns with external CFRP laminate application. One-layer and two-layer application, and hoop versus inclined application, were considered. The theoretical of representative confined columns were contrasted against corresponding values from design guidelines. It was found that the guidelines significantly under-predict the strength, maximum stress and strain in CFRP confined columns. The extra CFRP layer was helpful in enhancing the column performance. The numerical model axial capacities were in line with published literature. The failure tensile strain in CFRP was quite a bit larger than the manufacturer suggested value. Inclined CFRP application was not as effective as the hoop application. An optimum value of the CFRP confining strength can be recommended to increase the accuracy of the design guidelines. The strain efficiency factor from ACI, which accounts for premature failure of the CFRP jacket, does not take into account the FRP contributions.

Heterogeneous cellular network is considered as an important network architecture to improve spectral efficiency and energy efficiency. Extensive research has revealed that spectral efficiency and energy efficiency could be two conflicting performance metrics under most scenarios. Toward the next generation 5G wireless systems, both spectral efficiency and energy efficiency become increasingly important. How to design a wireless system that jointly considers/optimizes these two performance metrics is critical yet challenging. This paper jointly analyzes the area spectral efficiency and area energy efficiency in a wireless heterogeneous network with inter-tier fractional frequency reuse. Proportional fairness resource allocation is used to balance the spectral efficiency and user fairness within each cell. A theoretical framework is formulated to analyze the area spectral efficiency and area energy efficiency in such a system. Fractional frequency reuse and proportional fairness resource allocation define the optimal power reduction factor and fractional bandwidth partition to maximize the joint area spectral efficiency and area energy efficiency. The system performance is evaluated by using the proposed scheme with different system parameter settings including base station densities, cell fractional bandwidth partition, power threshold, and base station power consumptions. The study shows that fractional frequency reuse with proper settings can significantly increase the area spectral efficiency and area energy efficiency in wireless heterogeneous networks.

The research focuses on strength efficiency of rotary kiln metakaolin and flash metakaolin in concrete. The Smith and Bolomey modified model is used to develop efficiency factor (k) for cal...

Discrete dipole approximation (DDA) is a well-known method which is generally used to simulate the interaction of nanoparticles with the electric field of incident light. In this paper, DDA has been used to simulate different optical properties (absorption efficiency factor, scattering efficiency factor, extinction efficiency factor, phase lag efficiency factor and 3D near electric field) of ZnO nanoparticles (NPs) and ZnO-PVP composite. The particle sizes are varied and size corrected complex dielectric function of ZnO and its composite have been used as inputs of the simulation. The particle sizes of ZnO NPs and ZnO-PVP composites have been varied from 22 nm to 38 nm in simulation. The peak position of absorption efficiency factor matches perfectly with the experimental absorbance when the size of ZnO NPs is taken as 26 nm. The same phenomenon happens in case of ZnO-PVP composite when the size of composite NPs is considered as 28 nm. The particle within dielectric medium acts as particle with higher effective radius as the near electric field increases due to presence of local dielectric medium. We have also calculated other optical parameters of ZnO NPs and ZnO-PVP composites. Small but not negligible changes in optical properties are observed due to incorporation of PVP with ZnO nanoparticles.

The ability to accurately predict the CO2 storage resource in saline formations is important to make high-level, energy-related government policy and business decisions. CO2-SCREEN (Storage prospeCtive Resource Estimation Excel aNalysis) is a tool developed by the United States Department of Energy − National Energy Technology Laboratory (US-DOE-NETL) to screen saline formations for prospective CO2 storage resources. CO2-SCREEN uses DOE methods and equations to serve as a consistent mechanism for calculating prospective CO2 storage resources. CO2-SCREEN is comprised of two files: an Excel file used for inputs and outputs and a GoldSim Player file used to run Monte Carlo simulations. CO2-SCREEN requires input of physical geologic parameters (i.e. thickness, porosity) as well as efficiency factor ranges (i.e. net-to-gross thickness) to calculate a mass storage estimate. An application of CO2-SCREEN is demonstrated here using well log data from the Oriskany Sandstone portion in Pennsylvania. The Oriskany Sandstone is divided into 20 km x 20 km grid cells in which 151 cells contain well log data. CO2-SCREEN calculates prospective CO2 storage resource for each grid cell based on the well log data and uses lithology and depositional environment information for efficiency factor ranges. The Oriskany Sandstone CO2 storage resource estimate for Pennsylvania, calculated by CO2-SCREEN, ranges from 0.07 to 1.28 gigatons (Gt) with a P50 value of 0.32 Gt. This resource assessment analysis is done to demonstrate the use of CO2-SCREEN and results are comparable to previous studies which encourages the application of CO2-SCREEN to other saline formations and warrants exploring the expansion of this tool to assess the CO2 storage resource in other formations such as shale and depleted oil and gas reservoirs.

In cold rolling of strip, flatness defects typically appear in strip when subjected to heterogeneous thickness reductions across the width of strip. As crown and flatness are interrelated, the crown ratio variation is used to qualitatively predict flatness defect mode. An investigation on the shape prediction and control of strip is presented in this paper. Taking these purposes into account, a three-dimensional finite element model for the Universal Crown Control mill (UCM mill) and strip containing different basic crown patterns is developed, and applied to two questions, namely prediction of flatness defect position and analysis of actuator control efficiency. The results indicate that the approach of crown ratio factor only gives the prediction for the edge and center waves, but it can’t distinguish quarter-wave. Therefore, an improved approach based on the varying curve of crown ratio, which can give the location of the flatness defect in more detail, is proposed. Moreover, combined with the study concerning control feature and capacity on thickness profile and flatness of strip, an original solution for obtaining the actuator efficiency factor is implemented. Finally, the curve of actuator efficiency factor obtained by the model is tested online in a flatness closed-loop control system.

This article presents an experimental investigation carried out to assess the mechanical properties of Quaternary Cement Concrete (QCC) for M25 grade and 0.40 as water/binder ratio. Total of 40 mix...

This study investigated the behaviors, strut efficiency factor, and the effective width of corrosion-damaged half-bottle shaped struts. Six half-bottle shaped struts were subjected to varying aimed corrosion levels (0%, 3%, 6%) with different reinforcement mat rotation angles (0°, 45°), and their behaviors and typical failure modes ascertained. Strut efficiency factors and effective width were calculated and evaluated. Average strength of 6% corroded struts was 30% less than those of uncorroded struts. The AASHTO LRFD 2013 process predicted strut efficiency factor of corrosion damaged struts better than ACI 318–14 and EN 1992. Strut effective width also reduced with increasing reinforcement corrosion. The theoretical effective width near the load bearing plate was underestimated compared to the measured effective width, while the effective width far from the load bearing plate was overestimated.

Recommendations in many of the current design codes like the Eurocode and the AASHTO LRFD Bridge Design Code discount the effect of transverse reinforcement on strength of bottle shaped struts whereas the mechanics of the force system within a bottle-shaped strut suggests otherwise. In this investigation, the effect of amount of transverse reinforcement on strength of steeply inclined normal-strength and high-strength concrete bottle-shaped struts measured in terms of efficiency factors has been experimentally investigated for three transverse reinforcement ratios - 0.0031, 0.0046 and 0.0069, with the control bottle-shaped strut being transversely unreinforced. Efficiency factor increases of 31% and 25% in the normal-strength and the high-strength concrete bottle-shaped struts respectively were obtained when the transverse reinforcement ratio was increased from nil to 0.0031 whereas for the higher reinforcement ratios the increase in efficiency factor was relatively smaller. Service load crack widths in all the transversely reinforced struts were less than an upper bound value of 0.3 mm. The results of this investigation emphasise the role of transverse reinforcement in the strength of bottle-shaped struts and indicate that the 0.003 transverse reinforcement ratio recommended in the ACI 318-14 Building Code is the optimum amount of such reinforcement in normal-strength and high-strength concrete bottle-shaped struts.

A series of large-scale direct shear tests were conducted to investigate the behavior of unreinforced and geogrid-reinforced ballast at different rates of shearing. Fresh granite ballast with an average particle size ( D 50 ) of 42 mm and five geogrids having different aperture shapes and sizes was used in this study. Tests were performed at different normal stresses ( σ n ) ranging from 35 kPa to 140 kPa and at different rates of shearing ( S r ) ranging from 2.5 to 10.0 mm/min. The laboratory test results revealed that the shear strength of ballast was significantly influenced by the rate of shearing. The internal friction angle of ballast ( φ ) was found to decrease from 66.5° to 58° when the shearing rate ( S r ) was increased from 2.5 to 10.0 mm/min. It is further observed that the interface shear strength has improved significantly when the ballast was reinforced with geogrids. The interface efficiency factor ( α ), defined as the ratio of the shear strength of the interface to the internal shear strength of ballast, varies from 0.83 to 1.06. The sieve analysis of samples after the testing reveals that a significant amount of particle breakage occurs during shearing. The value of breakage, evaluated in terms of Marsal's breakage index ( B g ), increases from 5.12 to 13.24% with an increase in shearing rates from 2.5 to 10.0 mm/min. Moreover, the influence of aperture shape and size of geogrid on the behavior of ballast-geogrid interfaces was also examined in this study.

This research examines the efficiency factors (k) of burnt clay (BC) and cement kiln dust (CKD) and their effect as a substitute for Portland cement (PC) on the properties of concrete. Different blends were tested under different points in time. X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) techniques were used for determining mineralogical composition and characterizing of the material used. Results showed that, replacing PC with up to 20% CKD had a negligible effect on concrete strength and durability while addition of higher percentages of CKD and the presence of BC resulted in reduction of strength. The CKD-concrete blends resulted in higher k and strength than the BC blends. The changes in k values after the age of 28 days were negligible in both materials at all percentages of replacement. The alkali-silica reaction (ASR) tests showed that all specimens experienced changes in length. In general, these changes in specimens lengths tended to reduce with time. The initial surface absorption tests (ISAT) showed that blended concrete experienced a reduction in flow rate compared with the control mixture. The XRD, XRF and SEM analyses showed different concentrations of binders for the different concrete blends.

WOS: 000436225600036, In this study, the hydrogen fuel effect on the exergetic performance of a turbojet engine used in a military trainer aircraft is investigated. For the first step, the performance assessments of the exergetic performance are conducted according to jet fuel usage and the actual test cell data of the engine. For the second step, an exergetic evaluation is parametrically estimated to use the hydrogen fuel in the engine. Finally, the performance results of the engine run by jet fuel are compared with the performance results of the engine run by hydrogen fuel. Regarding the results of this study, by using hydrogen fuel in the engine, the exergy efficiency of the engine decreases from 15.40% to 14.33%, while the waste exergy rate increases from 6196.51 kW to 6669.4 kW. At the same time, the exergy rate of the fuel rises from 7324.87 kW to 7785.25 kW, hence the specific fuel exergy of the hydrogen fuel is higher than that of the jet fuel. The waste exergy flow cost of the engine rises from 16.52 x 10(-3) US$/kW to 17.79 x 10(-3) US$/kW. The environmental effect factor of the engine escalates from 5.49 to 5.98 and the ecological effect factor increases from 6.49 to 6.98. On the other hand, the exergetic sustainability index of the engine reduces from 0.182 to 0.167 when the sustainable efficiency factor of the engine goes down from 1.182 to 1.167. Between the components, for both jet fuel and hydrogen fuel, the CC has the highest values of the fuel exergy waste ratio, the relative waste exergy ratio, the product exergy waste ratio, the fuel ratio indicator, the product ratio indicator, the waste exergy cost flow, the environmental effect factor, the ecological effect factor, and the exergetic improvement potential when the CC has the lowest values of the exergy efficiency, exergetic sustain ability index, and sustainable efficiency factor, respectively. The reason for this result is that the combustion process contains high irreversibities. The obtained results indicate that the hydrogen fuel usage in the turbojet engine badly affects the exergetic performance of the engine and its components (especially the combustion chamber) hence the specific exergy of the hydrogen fuel is higher than the jet fuel's. On the other hand, the exhaust emissions emitted to the environment decrease from 0.509 kg/s to 0.0045 kg/s with the hydrogen fuel usage.

The article deals with the issues of labor motivation. Motivation, as a process of influence on a worker-person, occupies an important place in the system of enterprise management, personnel management and labor management. The essence of motivation is defined as a set of inductive causes, factors influenced by an employee in a particular situation. The authors substantiate the role of needs, interests, values and motives in creating conditions for effective work, which necessarily includes the quality of work. Moreover, in today's conditions, effective quality work is decent work. The main approaches to the definition of the concept of «motivation» are presented and the essence of material and non-material motivation at the enterprise is disclosed. The paper explains the need for a systematic approach to the formation of types of motivation, needs, motives, incentives, modern worker who strives not only for material wealth but also wants to be engaged in interesting, meaningful work, to enjoy it. Describing the main theories of motivation, the authors substantiate the possibility of their use in practical activities to create conditions for effective work at the enterprise. Motivation is considered as the factor of labor efficiency.

A computer simulation scheme with a rapid thermodynamic model is developed to predict the diesel engine HRR (heat release rate) and performance characteristics with DME as a fuel. The bmeps (MPa) are simulated as 0.5 (optimum power output) and 0.3, 0.4, 0.6 (other power outputs) with diesel and with DME in four steps sequentially. Initially, HRR is predicted by modifying four double Wiebe function parameters; the equations of heat release and combustion duration of diffusion phase and the efficiency factors of premixed and diffusion phase as 2.25 and 3.25 respectively (obtained by qualitative and approximate fitting by trial and error method). Obviously 99% combustion efficiency assumption with efficiency factor as 6.9 is excluded. Secondly, all Wiebe parameters are computed by using LCF (load correction factor which is the ratio between mass flow rates of diesel of optimum and other power output) alone and by using LCF and OCF (oxygenate correction factor which is the ratio between mass flow rates of DME and diesel of identical power output) in other steps. Premixed and diffusion phase peaks (J/degree) with DME are 13.73 and 31.47 (0.3 MPa); 23.18 and 47.25 (0.6 MPa). Performance predicted with 1.2% accuracy is validated by SAE and USA Army literature.

Many applications of electromagnetic scattering involve particles immersed in an absorbing rather than lossless medium, thereby making the conventional scattering theory potentially inapplicable. To analyze this issue quantitatively, we employ the FORTRAN program developed recently on the basis of the first-principles electromagnetic theory to study far-field scattering by spherical particles embedded in an absorbing infinite host medium. We further examine the phenomenon of negative extinction identified recently for monodisperse spheres and uncover additional evidence in favor of its interference origin. We identify the main effects of increasing the width of the size distribution on the ensemble-averaged extinction efficiency factor and show that negative extinction can be eradicated by averaging over a very narrow size distribution. We also analyze, for the first time, the effects of absorption inside the host medium and ensemble averaging on the phase function and other elements of the Stokes scattering matrix. It is shown in particular that increasing absorption significantly suppresses the interference structure and can result in a dramatic expansion of the areas of positive polarization. Furthermore, the phase functions computed for larger effective size parameters can develop a very deep minimum at side-scattering angles bracketed by a strong diffraction peak in the forward direction and a pronounced backscattering maximum.

This paper presents an study on the rupture strain of cylindrical fiber-reinforced polymer (FRP) jackets under internal ice pressure. A total of 45 cylindrical FRP jackets were prepared using three unidirectional carbon, glass, and basalt fabrics in three different internal diameters, namely 60, 114, and 216 mm, and one-, two-, and three-plies. Three jackets for each combination were typically tested and the average hoop rupture strains were obtained and compared to the rupture strain of flat coupons in the form of a strain efficiency factor. It was found that the strain efficiency factor ranged from 0.53 to 1.05 with an average of 0.77. A new analytical model was also developed based on the bi-axial state of stress in a cylindrical FRP jacket to obtain the rupture strain and strain efficiency factor of the FRP jacket using a closed-form solution. The model engaged four major parameters, namely: diameter, thickness, axial/transverse strength ratio, and Poisson’s ratio of the FRP jacket. The two latter parameters were eliminated after a parametric study to propose a simplified formula. The analytical and simplified models predicted the experimental strain efficiency factors with an average error of −3.4% and −4.6%, respectively.

The Brazilian National Standard for structural masonry considers the compressive strength as the most important factor for design of structures. For the use of ceramic blocks, NBR 15812-1 (ABNT, 2010) recommends that the prism/wall efficiency factor should be at least 0.70. For that, it is important to assess the geometrical and mechanical properties of blocks and the mechanical properties of mortar, as the failure mechanism of prisms is associated with internal stresses in the brick-mortar interface. Although this design strategy has been successfully implemented, it does not consider a series of uncertainties in the production of the block and in the masonry construction process. Taking this into consideration, this paper aims to provide a statistical and reliability assessment of blocks produced by a specific manufacturer, between February and April 2014. Experimental measurements and tests provided data to a statistical characterization of dimensional parameters and compressive strength. A reliability-based evaluation was then carried out to describe the probabilistic performance of masonry subjected to compression by using First Order Reliability Method (FORM) and Monte Carlo simulation.

Andesite stone is widely used in civil engineering and architectural applications in Turkey. Mining, cutting and polishing of andesite stone leads to the generation of significant amounts of waste material. Andesite contains SiO2 as the main component. Therefore, andesite may have pozzolanicity and thus may be used as mineral additive in concrete. In this study, the efficiency factor of andesite waste powder as a mineral additive was investigated and compared with F type fly ashes. The efficiency factors of mineral additives were also analyzed according to the curing ages of concrete specimens. Concrete specimens were prepared at various cement dosages to determine the efficiency factors of mineral additives at different replacement levels. The compressive strengths of concrete specimens were tested at 28th and 90th days. The efficiency factors were calculated by determining the variable Feret coefficient for each specimen series. For C40 strength class, the optimum replacement rate of andesite waste powder was determined as 10% at curing ages of 28 and 90 days.

The effect of backing material, projectile velocity and tile thickness on the ballistic efficiency of ceramic materials was studied against 7.62 mm AP projectile in depth of penetration (DOP) test configuration. An analysis on variation in differential efficiency factor (DEF) with respect to backing material was carried out. The factor responsible for variation in DEF was eliminated using a normalization method. A new definition (NDEF/ NBE) is proposed for calculation of ballistic efficiency. Using the new definition a comparison of ballistic efficiency of hot pressed boron carbide, alumina and zirconia toughened alumina were done for different projectile velocities and tile thickness. The DEF was found to increase with increase in projectile velocity, but NDEF and NBE were found to decrease with increase in projectile velocities. Even though the DEF, NDEF and NBE have produced different ballistic efficiencies they all have produced similar trends with respect to tile thickness.

In this paper, a novel composite efficiency factor model has been proposed for the trajectory optimization of gun-launched gliding guided projectiles. The composite efficiency factor is based on th...

A method for energy efficiency improvement of power stations equipment for metallurgical complexes is proposed. The method is intended for load optimization of steam boilers equipment. Several optimization criteria are considered: (1) minimum of natural gas consumption by a group of steam boilers with the restrictions for steam generation, consumption of secondary energy resources and mode parameters; (2) maximum of efficiency factor; (3) combined criterion for minimum of natural gas consumption and maximum of efficiency factor. The optimization problem solution is based on steam boiler process models. The process models represent power characteristics of the equipment. The process models use optimal energy characteristics of equipment operational data as well as normal data. An example for load optimization of boiler equipment at the power station of a metallurgical complex was given to illustrate the proposed method. The results show that the optimization method allows to decrease the consumption of natural gas to 5%.

We have developed an experimental investigation procedure and have carried out a comprehensive analysis of the effect of the design and kinematic characteristics of high-speed and hybrid stirrers on the intensity and efficiency of mixing for liquid heterogeneous systems. We have shown that compared with the high-speed stirrer, the efficiency factor for the hybrid stirrer increases by 25% on the average. The intensity of mixing when using the hybrid stirrer increases compared with the high-speed stirrer, and this trend is enhanced as the speed (rpm) of the stirrer increases.

This study aims to present an approach to investigate the reliability levels of reinforced concrete (RC) columns confined by Fiber Reinforced Polymers (FRP) subjected to concentric loading. First, the statistical properties of random variables such as model error, FRP strain efficiency factor (FSE factor) and axial resistance of columns are investigated. Then in respect to the existing correlation between variables and extensive collected database, an appropriate probabilistic model for model error, FSE factor and compressive resistance of RC column is proposed. In addition, the effects of live-to-dead load ratio, reinforcement ratio and the confinement levels on the reliability of FRP-confined columns are studied through a reliability analysis. Furthermore, based on existing studies, reliability indices for various levels of confinement are calculated. Finally, a calibration analysis on safety factors of ACI 440.2R-17 guideline and shape factor of rectangular cross-section is presented.

Low-grade calcined clay mixed with limestone powder (Limestone-Calcined Clay, LCC) is a new kind of cement replacement material in the face of the inadequate availability of conventional pozzolans such as fly ash. Because of the high water demand and likely insufficient strength gain of LCC, the information on using more than 50% of LCC in the binder is extremely limited, which hinders using LCC in a higher replacement level to develop greener concrete. This study attempts to address this knowledge gap by producing Grade 45 structural concrete with ultrahigh-volume LCC (UHV-LCC). UHV-LCC mortar mixes with various LCC/binder ratios (50-80%) and water/binder ratios (0.3-0.4) were firstly examined to determine the cementing efficiency factor of LCC. Four Grade 45 UHV-LCC concrete mixes with different LCC/binder ratios (50%, 60%, 70% and 80%) were then designed and demonstrated. With the judicious choice of water/binder ratio, UHV-LCC concrete achieved compressive strength of 33-37 MPa at 3 days, 47-51 MPa at 7 days, 56-58 MPa at 28 days, and 62-64 MPa at 90 days. The flexural strength of UHV-LCC concrete was 2-10% higher than that of plain Portland cement concrete with identical compressive strength class. Additionally, UHV-LCC concrete showed 36.8-44.4% lower total embodied carbon than plain Portland cement concrete, and a higher LCC/binder ratio resulted in lower embodied carbon in Grade 45 concrete. A 5-D representation was used to evaluate different concrete mixes by comprehensively considering the mechanical, environmental, and economic performance. Our findings are useful for the mix design of sustainable concrete with LCC.

Medicinal and aromatic plants (MAPs) have always been a source of a vast variety of secondary metabolites with high biological potency. There is to-date an enormous ongoing research on the development of sophisticated methodologies for the production of bioactive MAP extracts, which may be applied in a spectrum of products, such as foods, pharmaceuticals and cosmetics. A great concern in implementing an extraction protocol is the use of appropriate conditions to achieve maximum efficiency with minimum cost, energy, and environmental aggravation. Although several parameters may affect the effectiveness of an extraction process, time and temperature are of utmost importance, and largely define both operating cost and quality of the final extract. Thus, there is a need for a simple tool of assessing an extraction method and allow for sound comparisons. In such a frame, this study introduces for the first time the concept of “extraction efficiency factor” (FEE). The purpose was to combine time (t) and temperature (T) in a single factor for evaluating extraction processes in general, and to enable easy and sound comparison of results obtained by solid-liquid extractions of MAPs. Such an approach could facilitate process control and would permit trading time and temperature of a treatment such that equivalent final effects are obtained.

The main objective of this paper is to perform thermodynamic analysis of a TF33 turbofan engine fueled by hydrogen as opposed to kerosene. Considering the performance parameters, environmental indicators, and sustainability metrics of the TF33 operating with hydrogen and kerosene, a comprehensive thermodynamic comparison is achieved. In addition, its performance, and its environmental, and sustainability assessments are thermodynamically evaluated. Accordingly, the following is noticed at the take-off phase as an outcome of a transition from the kerosene-turbofan to the previously mentioned hydrogen-turbofan: (i) The fuel flow reduces by 63.83%; (ii) The specific fuel consumption decreases by 60.61%; (iii) The energy efficiency reduces by 0.757%; (iv) The thermal limit ratio decreases by 1.55%; (v) The fuel cost rate increases by 290.91%; (vi) The environmental effect factor (EEF) for combustion chamber (CC) increases by 14.25%; (vii) and the sustainable efficiency factor (SEF) and exergetic sustainability index (ESI) for CC reduce by 6.72% and 12.51%, respectively. In addition, the benefits and drawbacks of using hydrogen as fuel in the engine are presented comprehensively under the guidance of the results. The main contribution of this research lies in whether or not the result of using hydrogen as a fuel in gas turbine engines by employing thermodynamic analysis results in a more efficient and more environmentally friendly engine.

Mathematical modeling of the bleaching process with a chemical reaction and diffusion of bleaching agent into a thin polymeric matrix film by movement through the micropores is studied in the present paper. The model was developed after considering theoretical methods of chemical engineering, the physical operation mechanism of the bleaching process and the main parameters that influence the diffusion mechanism. The efficiency factor for chemical kinetics of first and nth order processes were described using analytical solutions and perturbation methods. For the solution of the dynamic model, two cases of boundary conditions were explored. The first case describes diffusion in a well-stirred medium and the second case describes the situation when the bulk fluid moves slowly and interfacial resistance is present. In the latter case, the difference finite method was used as numerical tool for solving the problem and finding the concentration profile in the direction of the x-axis. Accordingly, experimental measurements were performed to determine the effective diffusion coefficient of bleaching agent in a polymeric matrix.

A novel two-way coupling multi-scale model was proposed to investigate the catalytic distillation process. In the model, a microscopic model that focuses on the reactive performance of structure catalytic packing was used to calculate actual rate for catalytic distillation process, which is the basic parameter for process simulation. Furthermore, the traditional process simulation was used to provide proper boundary conditions for microscopic model. In order to validate the multi-scale model, heterogeneously catalyzed hydrolysis of methyl acetate was employed as a test system. The simulated final conversions of methyl acetate and catalyst layer efficiency factors were in good agreement with experimental results. The results indicated that as the equivalent diameter of catalyst layer decreases from 25.4 mm to 8.1 mm, the catalyst layer efficiency factor rises to 200% approximately. This study could provide a theoretical guide for the optimization of catalytic packing structure.

The hydrological behavior of subsurface flow constructed wetlands changes with the operation time due to the gradual clogging of the matrix pores. However, studies on changes in hydraulics associated with the clogging process in constructed wetlands are still inadequate, with the variations of internal flow field that cause changes of hydraulic behavior still unknown. Conservative tracer tests and Computational Fluid Dynamics (CFD) software Fluent 6.3 were combined in this study to analyze the effect of clogging on hydraulic behavior in a vertical-flow constructed wetland experimental system. As the porosity of the experimental system decreased from 0.3669 to 0.316 caused by clogging, both the nominal hydraulic retention time and the actual average retention time decreased sharply, with the latter dropping even faster, indicating that the reduction of the pore volume caused by clogging is not the only reason for the decrease in the actual hydraulic retention time. During the experimental period, the system had a serious short-circuiting and mixing phenomenon, and the dead zone area was rather large. The overall hydraulic efficiency was poor. According to the CFD simulation results, which were verified by Nash-Sutcliffe efficiency factor (NSE), the flow rate in the experimental system increased with the operation time. Correspondingly, the time required to pass through the matrix pores decreased, which contributed to an additional drop in hydraulic retention time, along with the decrease of porosity.

The Mach-Effect thruster is a propellantless propulsion concept that has been in development by J.F. Woodward for more than two decades. It consists of a piezo stack that produces mass fluctuations, which in turn can lead to net time-averaged thrusts. So far, thrust predictions had to use an efficiency factor to explain some two orders of magnitude discrepancy between model and observations. Here, a detailed 1D analytical model is presented that takes piezo material parameters and geometry dimensions into account leading to correct thrust predictions in line with experimental measurements. Scaling laws can now be derived to improve thrust range and efficiency. An important difference in this study is that only the mechanical power developed by the piezo stack is considered to be responsible for the mass fluctuations, whereas prior works focused on the electrical energy into the system. This may explain why some previous designs did not work as expected. The good match between this new mathematical formulation and experiments should boost confidence in the Mach effect thruster concept to stimulate further developments.

In this paper, JT15D turbofan engine and its main subcomponents are assessed with the aviation, energy, exergy, environmental, and sustainability analyses. In the first stage, the system's specific thrust and specific fuel consumption of the engine are found as 315.9 N s/kg and 15.8 g/kN.s, respectively. Then, system's energetic efficiency is estimated as 21.15% and exergetic efficiency is accounted to be 19.919%. The system's exergetic improvement potential rate, productivity lack ratio and fuel exergy waste ratio are determined as 1573.535 kW, 402.024% and 80.081%, respectively. The ecological and environmental effect factors of the turbofan system are computed to be 5.020 and 4.020, respectively, while the sustainable efficiency factor and exergetic sustainability index rates are found as 1.249 and 0.249, respectively. Finally, among the system parts, the Combustion Chamber (CC) has minimum rates of sustainable efficiency factor, exergetic efficiency and sustainability index, while it has utmost rates of ecological and environmental effect factors, fuel exergy waste ratio, irreversibility and productivity lack ratios. As a general conclusion, the combustion chamber and low pressure compressor components should be optimized for better performance of the system.

As the main source of heat loss of flat-plate solar air collectors (FPSACs), single glazing cover reduces the thermal performance of FPSAC. This situation becomes serious when the ambient temperature is low or the inlet temperature is high. A double glass cover with good thermal insulation is a good solution. This work aims to investigate the thermal performance of double glazing FPSAC at low ambient temperature and high inlet temperature. The thermal performance of four FPSACs with single glazing (Model 1), double glazing filled with air (Model 2), double glazing filled with argon (Model 3), and vacuum glazing (Model 4) as the glass cover at different ambient temperatures, different heat transfer air (HTA) inlet temperatures, and different HTA volume flow rates are studied and compared. Result demonstrates that Models 2, 3, and 4 have better thermal performance at low ambient temperature and high inlet temperature compared with Model 1. When the inlet temperature is 65 °C and ambient temperature is −10 °C, the thermal efficiencies of Models 2, 3, and 4 are 1.65, 1.72, and 2.29 times higher than that of Model 1, respectively. The efficiency factor and total heat loss coefficient of Model 4 are 0.62707 and 2.21745, respectively.

An experimental study was performed in this paper to investigate the compressive behavior of carbon fiber-reinforced polymer (CFRP) nonuniformly wrapped seawater sea-sand concrete (SSC) cylinders. The effect of test variables on the mechanical performance was comprehensively discussed, including the clear spacing and thickness of external CFRP strips. The test results indicate that the failure process of tested specimens is less brittle compared with that of the fully or partially FRP-confined columns. Besides, the average ultimate stresses and strains of the specimens nonuniformly wrapped with two-layer external CFRP strips increase by 6.7%-27.4% and 5.9–41.6% respectively with the reduction of clear spacing ratio. Moreover, when the thickness of external CFRP strips double increases, the maximum increment of strength and strain at ultimate condition becomes 42.8% and 63.8% respectively. It is also shown that the FRP efficiency factor of confined specimens with nonuniform wrapping scheme is the highest among various strengthening strategies under the same FRP volumetric ratio. Finally, a new nonuniform confinement effective coefficient, as well as a analytical stress–strain model, is developed based on the available test results. Compared with several existing predicted models, the proposed model can provide more accurate and reliable predictions.