Індекс рубрикатора НБУВ: К637.400.5,27

Рубрики:

Електричне полірування металів

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

The methodology and results of a simultaneous study of causally linked parameters of mechanical vibration (cause) and surface irregularities (consequence) in flat milling with an end mill are given. The features of measurement and analysis of surface quality parameters through the application of the separation frequency method of profilogram harmonic components on the surface roughness, waviness, and the deviation of the profile are reviewed. A new method of profilogram digital processing is developed, comprising the steps of its digitization, low-pass filtering, and the formation of the roughness profile. The initial theoretical positions on modeling mechanical (elastic) waves which are caused by vibration in the cutting zone and propagate in a solid, liquid, and gas (air) media are presented. The results of experimental studies of milled surface profilogram and the vibro-displacement signal in the milling are given.

Індекс рубрикатора НБУВ: Ж364.2

Рубрики:

Наноматеріали

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: К663.42-1

Рубрики:

Покриття металів смолами та пластмасами

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ 

Wire ropes that have a wide range of applications endure loads, stresses, strains, and moments while carrying out the duty of carrying loads. Wire ropes and strands are frequently used as load carrying elements due to their flexible structure and being reliable products. A prestressing steel strand is a form of the pattern of 1 x 6 helical wires which supply extra stiffness. Contact conditions between adjacent wires, helical geometry of wires at outer layers make it difficult to find the mechanic response of wire ropes or strands under axial load. A good way to overcome this difficulty is to perform a computer-aided simulation with finite element method. In this study, a prestressing strand having 11,11 mm diameter is computer-aided modeled by using SolidWorks, and then ANSYS Workbench is used to determine the mechanical response of the investigated rope strand. The findings indicate that results remained in the elastic region in all finite element simulations until the strain value of 0,00728.

One of the most urgent problems concerning the design of inertial separation devices is the failure of the trapped liquid film from the contact surfaces due to the contact with the turbulent gas-liquid flow. For extension of the range of the effective inertial separation, a method of dynamic separation was proposed using the developed separation device with deformable sinusoidal walls. In this regard, the article is aimed at the development of the general methodology for the determination of the impact of hydrodynamic characteristics on the shape parameters for the deformed separation channel. The proposed approach is based on both physical and geometrical models. The first one allows obtaining compliance of deformable walls as a result of pressure distribution in the separation channel as a result of numerical simulation. The second one allows for obtaining variations of the main geometrical parameters of the proposed model using transfer functions. The relevancy of the proposed methodology was proved by the values of the relative errors for evaluating the variations of the amplitude and the radius of curvature.

In this paper, the optimal reactive power problem has been solved by the cultivation of soil optimization (CSO) algorithm. The reduction of real power loss is a key objective of this work. The projected CSO algorithm has been modeled based on the quality of soil which has been used in the cultivation of various crops season to season. With respect to the quality of the soil in the cultivation land, there will be a change in the poor-quality soil since there will up the gradation of the poor soil is done through by adding the nutrient contents. Depend upon the needs and about the type of cultivation farmers will improve the quality of the soil by adding valuable and various types of fertilizers (natural and artificial) such that it will enhance the fertile and growth (green) of the crops. Time to time farmers will choose appropriate nutrient contents that will be mixed with the soil in order to enhance the fertility of the soil. In standard IEEE 14, 30, 57 bus test systems Cultivation of Soil Optimization (CSO) algorithm has been tested. The CSO algorithm reduced the real power loss and control variables are within the limits.

Various concentrated works have been done in the area of computational vision regarding the circle and texture detections. Detection of circles in images can be beneficial for PCB components industries for the detection of capacitors in printed circuit boards, also for medicine in the detection of red cells, white blood cells, and leukocytes, and for applications which requires precision and assignments regarding the detection of circles in a digital image. In this work is utilized a benchmarking of images to detection circle boards of different radio values for the comparison with the work [1] of this article. The benchmarking of images is composed of five main images that are tested in the algorithm of detection of circles in MATLAB with different values of radio for each image. The results appoint an enhancement of 300 % concerning the algorithm proposed in work [1] showed in this article. In this work also would be plotted graphs concerning the accuracy of the new proposed algorithm with relation to the algorithm proposed in work [1], indicating better results concerning the GUI interfaces and capacity of detection circles.

Study in Wireless Sensor Network (WSN) has been becoming an emerging and promising research topic aiming for the advancement in the Internet of Things (IoT) for a reliable connection. The capability of the wireless sensor to be used in a complex environment can become hard to reach areas and also be able to communicate in an ad-hoc manner, attracted researchers in recent times. Development in wireless sensor network producing a lot of new applications to sense environment remotely are facing challenges restricting it to perform up to its potential. Data validation and data reliability are such existing problems in this domain that needed to be addressed. Because sensed data cannot be blindly trusted upon, as it may have faults and errors occurred with-in the sensing environment. Besides, to guarantee the active state of the sensing system in a remote area is also essential in terms of power usage and management. The focus of the paper is data validation acquired from sensors deployed in remote areas. Although, lots of data validation algorithms have been proposed by researchers to identify single data fault. However, our research identifies multiple faults, namely spike fault, out of range fault, outliers, and stuck at fault using a hybrid form of an algorithm. A comparison with the existing algorithm shows that the proposed algorithm improved data validation by 97 % in detecting multiple data faults using Artificial Intelligence techniques.

The primary direction of the increase of reliability of the automated control systems of complex electromechanical machines is the application of intelligent information technologies of the analysis of diagnostic information directly in the operating mode. Therefore, the creation of the basics of information synthesis of a functional diagnosis system (FDS) based on machine learning and pattern recognition is a topical task. In this case, the synthesized FDS must be adaptive to arbitrary initial conditions of the technological process and practically invariant to the multidimensionality of the space of diagnostic features, an alphabet of recognition classes, which characterize the possible technical states of the units and devices of the machine. Besides, an essential feature of FDS is the ability to retrain by increasing the power of the alphabet recognition classes. In the article, information synthesis of FDS is performed within the framework of information-extreme intellectual data analysis technology, which is based on maximizing the information capacity of the system in the process of machine learning. The idea of factor cluster analysis was realized by forming an additional training matrix of unclassified vectors of features of a new recognition class obtained during the operation of the FDS directly in the operating mode. The proposed algorithm allows performing factor cluster analysis in the case of structured feature vectors of several recognition classes. In this case, additional training matrices of the corresponding recognition classes are formed by the agglomerative method of cluster analysis using the k-means procedure. The proposed method of factor cluster analysis is implemented on the example of information synthesis of the FDS of a multi-core mine lifting machine.

The presented article is an attempt to evaluate the progress in the development of the mathematical simulation of the pressure-driven membrane processes. It was considered more than 170 articles devoted to the simulation of reverse osmosis, nanofiltration, ultrafiltration, and microfiltration and the others published between 2000 and 2010 years. Besides the conventional approaches, which include the irreversible thermodynamics, diffusion and pore flow (and models which consider the membrane surface charge for nanofiltration process), the application of the methods the computational fluid dynamics, artificial neural networks, optimization, and economic analysis have been considered. The main trends in this field have been pointed out, and the areas of using approaches under consideration have been determined. The technological problems which have been solved using the mentioned approaches have also been considered. Although the question of the concentration polarization has not been considered separately, it was defined that, in many cases, the sufficiently accurate model cannot be designed without considering this phenomenon. The findings allow evaluating more thoroughly the development of the simulation of pressure-driven membrane processes. Moreover, the review allows choosing the strategy of the simulation of the considered processes.

Analytical solution for application and comparison of Graphene Nanoribbon and Silicon Carbide for thermal and hydraulic performance in flat tube Multi-Louvered Finned Radiator is presented. The base fluid is composed of pure water and ethylene glycol at a 50 % volume fraction. The results were obtained for Nusselt number, convection heat transfer coefficient and pressure drop, for airflow in the radiator core and nanofluids in flat tubes. The main thermal and hydraulic parameters used are the Reynolds number, the mass flow rate, the Colburn Factor, and Friction Factor. In some situations, under analysis, the volume fraction, for Graphene Nanoribbon and Silicon Carbide, were varied. The value of the heat transfer coefficient obtained for Graphene Nanoribbon, for the volume fraction equal 0.05, is higher than twice the amount received by Silicon Carbide. The flow is laminar, for whatever the fraction value by volume of the Graphene nanoparticles when the mass flow of the nanofluid is relatively low. For turbulent flow and relatively small fractions of nanoparticles, the heat transfer coefficient is significantly high for mass flow rates of Graphene Nanoribbon. The pressure drop, for the same volume fraction of nanoparticles, is slightly higher than the pressure drop associated with Silicon Carbide. These high values for the heat transfer coefficient is a favorable result and of great practical importance, since lower values for the fraction in volume can reduce the costs of the compact heat exchanger (radiator).

The work is devoted to the study of heat and mass transfer in a liquid film flowing down on a heated surface under conditions of evaporation into a crossflow of a gas neutral with respect to the liquid. The work aimed to experimentally determine the average heat transfer coefficients from a heated surface to the film, heat transfer and mass transfer from the film to the gas flow and to establish their dependence on the input parameters of the heat and mass transfer process. To achieve this goal, an experimental setup was created, and a research technique was developed based on the proposed mathematical model of the heat and mass transfer process. The results of the study showed that the dependences of the average heat and mass transfer coefficients on the initial liquid flow rate are extreme with the minimum values of these coefficients at the liquid flow rate, which corresponds to the critical value of the Reynolds criterion Re l cr = 500, which indicates a transition from the laminar falling films to turbulent mode under the considered conditions. The dependences of the heat and mass transfer coefficients on other process parameters for both modes of film falling are established. A generalization of the experimental data made it possible to obtain empirical equations for calculating these coefficients.

Underwater communication has become a widely studied area in recent years and showed great potential to be an area of research. Acoustic communication is often preferred in underwater communication due to its suitability for an underwater diffusion environment. However, in underwater communication, the physical and chemical properties of the water environment affect sound propagation. Therefore, determining and examining parameters affecting channel performance in underwater communication plays an essential role in inefficient communication. In this study, the effects of salinity, depth, noise, temperature, and frequency parameters for the underwater channel model are examined. By determining the effects of these parameters on spherical and cylindrical propagation, suitable propagation geometry and parameter values for an efficient channel are investigated. In light of the results obtained, in case of studying in a limited area, the path and absorption losses can be reduced by selecting cylindrical propagation as a geometrical propagation model, thereby an efficient channel model can be formed.

One of the most energy-intensive processes is the drying process. Therefore, an important task is to reduce heat consumption for drying. Various ways to improve the drying devices of paper and cardboard machines are identified. The main disadvantages of these improvements are given. The limiting factor of heat transfer from water vapor to paper is established. The dependence of thermal resistance on the thickness of the condensate layer is given. The authors have developed a new design for condensate drainage. The developed design allows installing movable siphons without replacement of steam inlet heads of the old type (for fixed siphons) with their insignificant modernization and cutting of an annular groove inside the drying cylinder. This will ensure a minimum level of condensate and eliminate the possibility of suction of steam into the condensate return system. Additionally, this will reduce thermal resistance, heat loss, and reduce energy consumption for paper drying as a whole.

Thermodynamic analysis and economic feasibility of a gas turbine power plant using a theoretical approach are studied here. The operating conditions of Afam Gas Power Plant, Nigeria are utilized. A modern gas turbine power plant is composed of three key components which are the compressor, combustion chamber, and turbine. The plants were analyzed in different control volumes, and plant performance was estimated by component-wise modeling. Mass and energy conservation laws were applied to each component, and a complete energy balance conducted for each component. The lost energy was calculated for each control volume, and cumulative performance indices such as thermal efficiency and power output were also calculated. The profitability of the proposed project was analyzed using the Return on Investment (ROI), Net Present Worth (NPW), Payback Period (PBP), and Internal Rate of Return (IRR). First law analysis reveals that 0,9 % of the energy supplied to the compressor was lost while 99,1 % was adequately utilized. 7,0 % energy was generated within the Combustion Chamber as a result of the combustion reaction, while 33,2 % of the energy input to the Gas Turbine was lost, and 66,8 % was adequately converted to shaft work which drives both compressor and electric generator. Second law analysis shows that the combustion chamber unit recorded lost work of 248,27 MW (56,1 % of the summation), and 77,33 MW (17,5 % of the summation) for Gas Turbine, while air compressor recorded 11,8 MW (2,7 %). Profitability analysis shows that the investment criteria are sensitive to change in the price of natural gas. Selling electricity at the current price set by the Nigerian Electricity Regulation Commission (NERC) at zero subsidies and an exchange rate of 365 NGN/kWh is not profitable, as the analysis of the investment gave an infinite payback period. The investment becomes profitable only at a 45 % subsidy regime.

In the conditions of the global ecological crisis in the world and Ukraine, the issue of finding alternative energy sources becomes relevant. One of the most common types of renewable energy is solar energy. In Ukraine today, the most promising direction of using solar energy is its direct transformation into low-potential thermal energy. To get electric power, solar radiation is the mere alternative to electric power generated from mined fuel, and without the pollution of air and water, or adverse consequences manifested in global warming. The disadvantage of this type of installation is the limitation of the duration of light time, as well as the effect of cloudiness. During the day, the number of solar radiation changes, to stabilize it is necessary to accumulate and accumulate it for further use, the technical implementation of stable operation of solar installation due to the use of terrestrial radiation and the accumulator of a specific part of solar energy is proposed. The purpose of the work is experimental studies to ensure the stable operation of the solar collector under cloudy conditions. The paper is aimed at the stabilization of the operation of the solar installation and to obtain additional heat after the Sun's cloud cover. The use of a solar thermal collector is advisable in solar heating and hot water systems in conditions of alternating solar radiation. The results of physical modeling have proved the efficiency of the method of combining types of thermal radiation, due to the accumulation of energy it is possible to increase the quantitative index of solar energy in the conditions of cloudiness by 3 times.

A significant portion of the automobile and industrial sector is mostly dependent on the running of diesel engines as it is efficient and shifts a large of the goods around the globe and power various equipment. Also, as the use of energy as diesel fuel is increasing enormously with the expansion of industrial growth, diversification, this led to the accelerating global emissions, global climatic change, health issues, and exhaustion of fuels. To succumb this, alternative fuel is needed to fight against the ill effects and as a replacement to diesel fuel. Thus, vegetable oils as alternative fuels are drawing more attention as they are renewable and do not address the problem of greenhouse gas. In the present work, the cottonseed oil was chosen as the favorite among the vegetable oils due to its advantages like less pollutant level, excessive availability, etc. The transesterification process was used to produce the cottonseed oil biodiesel. This research aims to investigate efficiency, emission characteristics by using smooth diesel, cottonseed oil, and mixtures with varying composition from 20 % to 80 % in 20 % steps to identify sustainable fuel as a substitute for existing fuel and to overcome fuel demand and enviro effects. This test was conducted on single-cylinder four-stroke water-cooled diesel engines. From the results, it was revealed that cottonseed oil and its blends have a significant influence on performance and emission characters.

An important direction of forming an effective system for recycling waste of various genesis is to optimize the processes of their treatment using the latest information resources. The paper deals with theoretical studies of directions for the systematization and optimization of anaerobic waste processing technologies using ontological tools based on information resources. Significant scientific support to biochemical research is provided by electronic bioinformatics databases such as KEGG, BacDive, and EAWAG-BBD, etc., which provide access to a collection of graphical representations and text descriptions of metabolic or signal pathways, schemes of regulation of biological processes, information about the organism. They cover various aspects of bacterial and archaic biodiversity, information on microbial biocatalytic reactions and biodegradation pathways of mainly xenobiotic chemical compounds. Also, in the course of work based on analytical data of electronic databases of bioinformatics, in particular, the interaction of necessary ecological and trophic groups of microorganisms, biochemical simulation of anaerobic waste processing with biofuel production was carried out.

Індекс рубрикатора НБУВ: З294

Рубрики:

Електричне освітлення. Світлотехніка

Шифр НБУВ: Ж101239 Пошук видання у каталогах НБУВ