bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculating non-perturbative quantities through the world-line formalism
Authors: Antonov Dmitry
Published: June 2019

We present two applications of the world-line formalism to the calculation of non-perturbative quantities in QCD. The first quantity is the free energy of the gluon plasma in the high-temperature limit; the second quantity is the pair-production rate in the chromo-electric field of a flux tube. In the first case, where effects of spatial confinement in the dimensionally-reduced 3D Yang-Mills theory are primarily important, we calculate the free-energy density of a gluon propagating in the stochastic background fields through a suitable parametrization of the area-and the perimeter laws of the Wilson loop, which enters the corresponding one-loop effective action. In this way, we find that the order of the leading correction to the Stefan-Boltzmann free energy changes from

O

(
λ
)

for N ∼ 1 to

O

(

λ

3
/
2

)

for N ≫ 1, where λ is the finite-temperature’t Hooft coupling, and N is the number of colors. In the second case, we find that, in the London limit of the dual superconductor, the Schwinger pair-production rate, ∼ e−const·m

2, goes over to e−const·m
. Given that the flux-tube field is static, we find such a conversion of the Gaussian distribution into an exponential one, remarkable.
Processes with Photons and Gravitons
Authors: Schubert Christian
Published: June 2019

In this contribution to the memorial workshop in the honour of Victor Manuel Villanueva Sandoval, I give an overview over my long-term collaboration with Victor, which centered on effective actions, amplitudes and physical processes involving photons, gravitons and external fields.
Modification of D2-line absorption contours of alkali atoms in antirelaxation coated cells
Authors: Tsygankov E A , Fomichev D E , Chuchelov D S , Zibrov S A , Velichansky V L , Yakovlev V P
Published: June 2019

Absorption features in cells with antirelaxation coating in D2 -lines of alkali metal atoms due to the competition of cyclic and open transitions lying within the Doppler contour are studied. In cells of this type ensemble of atoms is optically pumped over all velocities and the entire volume of the cell during the characteristic time T, which noticeably exceeds local pumping times related to resonant atomic velocities. If the frequency scanning T, the retardation effect results in significant distortion of the laser wave absorption contour and to emergence of the hysteresis phenomenon. The developed theory for a realistic scheme of atomic levels with one cyclic and two open transitions describes experimentally observed absorption contours, their dependence on the light power and the frequency scanning direction.
Studies of space charge dominated electron photoemission at PITZ
Authors: Krasilnikov Mikhail , Chen Ye , Stephan Frank
Published: June 2019

Photoemission in modern high brightness electron sources is under studies at the PITZ photo injector. Space charge dominated photoemission in the presence of high RF field at the semiconductor photocathode is studied. By utilizing core and halo particle distributions based on measured radial laser profiles, simulations reproduce the behaviour of the measured emission curves for a wide range of RF gun parameters within the measurement uncertainties for Gaussian laser pulses. But applying this model to the case of long flattop photocathode laser pulses revealed discrepancies between experimental data and simulation results. Corresponding emittance simulations have been compared to measurements for both temporal profiles of the photocathode laser.
Random search for global extremum of a function using Markov chains simulation
Authors: Vladimirova L V , Ovsyannikov D A
Published: June 2019

The problem under study is global extremum search for multiextremal function. Random search method based on Markov chains simulation is used. A comparative analysis of this method with another method – the method of random search for the global extremum with “memory”, using the normal distribution – done.
The control of unprocessed oil stratums debit restoring by method of ultasound influence with well neutron generator
Authors: Berdonosova N A , Bogdanovich B Yu , Dmitriev M S , Zhuyikov Yu F , Ilyinskiy A V , Nesterovich A V , Shikanov A E , Shikanov E A
Published: June 2019

The examples of experimental studies of oil stratum debit restoring by method of ultrasound influence to stratum are given. The method of control of such unprocessed oil stratum restoring is proposed. It uses well neutron generator with vacuum accelerating tube and neutron reagent method with pumping of neutron absorbing salt solution to stratum. The results of its successful testing are presented.
Image Processing System for Early Detection of Cocoa Fruit Pest Attack
Authors: Basri  , Harli  , Indrabayu  , Areni Intan Sari , Tamin Rosmawati
Published: June 2019

Cocoa (Theobroma cacao L.) is one of the leading commodities that developed in quality and quantity. Efforts through socialization and counseling in the field of cocoa cultivation for the farmers are always reminding know the importance of identifying symptoms from pest attacks could earlier makeup so that preventive actions that do not damage the environment or agricultural land. The study aims to create an early detection system based on image processing on symptoms of pest attacks on cocoa fruits. The early detection system involves training the data and test the data as a result of capture pictures of ordinary cocoa fruits and reviews those attacked by pests in real time at the location of cocoa plantations. Image processing techniques are integrated into the application software to be Able to identify the pixel characteristics of capture images of cocoa fruits. The results of the study showed that the ability of the system to detect the symptoms of pests in training the data was 100% and the test of data was 70%. This result showed that the applications could be recommended to be developed on a larger scale so that it will be helpful for cocoa farmers.
A Study of Limited Resources and Security Adaptation for Extreme Area in Wireless Sensor Networks
Authors: Parenreng Jumadi Mabe , Kitagawa Akio , Andayani Dyah Darma
Published: June 2019

WSNs have five main components namely, the sensing device, processor, memory, power supply, and transceiver. The power supply, processor, and memory are the main resources and have limited resources; therefore, resource availability in WSNs must be maintained. With limited resources available, the WSNs is required to be able to work as efficiently as possible, operated in a long time period and secure due to its placement in extreme areas. Another challenge is to choose the WSNs that has short time operation with strong security or long time operation with adaptable security. This article provides limited resource solutions to WSNs whose placement is in extreme areas that are impossible to do maintenances. As a solution, an adaptation approach to resource availability and security is used as offered by the ARSy Framework. For testing, we use components such as Raspberry pi 3 Model B and DS18B20 temperature sensor. The advantage the raspberry pi because its CPU and Memory resources have a large capacity. With these advantages, it is highly manageable, allows to integrate several types of sensors in one raspberry pi unit, and the use of battery resource becomes optional. The battery will be only used based on the design requirements because the battery consumption is wasteful. The result of the research shows performance ARSy framework compared to the system that works without ARSy framework mechanism.
Economic Value of Mangrove Forest in Pannikiang Island, Barru District, South Sulawesi, Indonesia
Authors: Arfan Amal , Sanusi Wahidah , Rakib Muhammad , Taufieq Nur Anny Suryaningsih
Published: June 2019

Mangrove forest area is a very important area in Pannikiang. Mangrove forests in this area are used by the community as a livelihood. This study wants to learn about the economic valuation of mangrove forests on Pannikiang Island, Makassar. A total of 60 respondents were interviewed in depth. Benefit value, calculated using the value of Direct Use, Indirect Use Value, Option Value, Existence Value, and Total Economic Value. The total economic value of mangrove forests on the Pannikiang Island Rp. 16,155,904,158/year or Rp. 183,007,523,300/ha/year. The patterns and manner of utilization, resource mangrove ecosystem is using gear nets, traps, hooks iron in catching shrimp and crab, develop nursery mangrove system with scraped or directly from the fruit, using gear nets, traps, using an iron hook and set traps crab (rakkang) in catch crabs, catch the bat, found in the mangrove forest, using the net, made bridge length, and the middle of the mangrove forest tower area so that the end could be resting and go up to the tower to see the entire expanse of the forest mangrove Pannikiang Island, wanamina cultivation, which combines farming of fish/shrimp with mangroves.
Phytochemical Test and Toxicity Test for Methanol Extract of Belajang Susu (Scindapsus pictus Hassk.)
Authors: Salempa Pince , Muharram  , Jumadi Oslan
Published: June 2019

Plant Belajang Susu (Scindapsus pictus Hassk.) is a species of the genus Scindapsus including Araceae family that has long been used by Mambi traditional communities as anticancer. Plant that include genus Scindapsus are generally used as ornamental plants, and there are also used as medicinal plants because they contain active compounds and can be antiinflammatory, analgesic, antioxidant and anti-tumor. Methods used included of extraction or maceration, phytochemical test, fractionation and bioactivity test extract with Brine Shrimp Lethality by using Artemia salina. From the results of the phytochemical test it is known that methanol extract of Belajang Susu contain alkaloid and steroid, while toxicity method Brine shrimp lethality test, showed that activity extract methanol Belajang Susu with each LC50 value 1,1365 μg mL−1.
The Influence of Some Plant Extracts that are Potential in the Antichiperglicemia
Authors: Mu’nisa A. , Syamsia  , Rachmawaty  , Muflihunna A. , Sari Dwi Kesuma
Published: June 2019

The underline of this study to investigate the antihyperglycemic effect in mice groups. The plants that have been tested as anti-hyperglycemia are cat root leaves (Acalypha indica), maja leaves (Crescentia cujete L.), and alang-alang plants (Imperata cylindrica). This study used 45 ICR male mice divided into 3 treatment groups, namely the normal mouse group, hyperglycemic mice group, and mice group with the provision of cat leaf extract, maja leaves, and alang-alang plants with a dose of 250 mg kg-1 bw. The results show that the administration of these three plants can reduce the blood glucose levels of mice by 22-27%. The conclusion in this study was that the extract of cat’s root leaves (Acalypha indica), maja leaves (Crescentia cujete L.), and alang-alang plants (Imperata cylindrica) showed an effect as anti-hyperglycemia.
The Effect of Graving Extracts as a Million Grower
Authors: Juliyanti Ayuningrum S. , Jumadi Oslan , Idris Irma Suryani , Kaseng Ernawati S.
Published: June 2019

This research was aimed to determine the effect of algae extract as a driver of maize growth (Zea mays L.) using Randomized Block Design (RAK) with 3 replications. Making of algae-based organic fertilizer that has been done by extract consisting of three types of algae are Eucheuma sp., Sargassum sp., and Ulva sp. Further liquid fertilizer is tested against corn crops (Zea mays L.). Algae extracts are used in plants, either by spraying or by mixing with soil. The observation parameters included stem circumference (cm), leaf chlorophyll content (%), vegetative vegetative biomass (g), corncob (g), corncob (cm), leaf nitrogen (%), and seed nitrogen (%). The use of algae extracts to improve the quality and quantity of maize growth showed the growth of corn crops that tended to be better than controls. Of all existing treatments, algae extract showed Eucheuma sp. Algae extract on the measurement of vegetative biomass, and leaf nitrogen showed the highest yield, Sargassum sp. Algae extract showed the highest result on the measurement of stem circumference and tuna weight, whereas Ulva sp. Algae extract showed the highest yield on measurements of ear and nitrogen grains.
Determination of the Growing Season for Dry Land Agriculture Based on Thornthwaite Method in Bulukumba Regency, South Sulawesi Province
Authors: Umar Ramli , Yusuf Muhammad
Published: June 2019

Drought events in a region are strongly related to the surface water availability and low rainfall. Furthermore, drought conditions impact the threat of food security. Bulukumba Regency in South Sulawesi Province is one of the areas that are prone to drought and the risk of crop failure. Therefore it needs anticipatory action to understand the drought index in this region. This study aims to identify the conditions of drought and agitation in the Bulukumba District of South Sulawesi Province. The results of the identification then became the basis for determining the growing season in various types of dryland agriculture cultivation. This study used the Thornthwaite method with a water balance and drought index approach. The sampling method in this study was purposive sampling. Data collection techniques carried out are observation techniques, laboratory analysis techniques, and documentation techniques. Data processing used quantitative techniques and descriptive approaches. The results of the study show that the growing season in dryland agriculture in November, December, and January based on the availability of water in this region. Conversely, the availability of water is very low in May to September and not appropriate to handling the cultivation.
The effectiveness of The Formulation of Cocoa Pod Husk (Theobroma cacao L.) Based Botanical Fungicides on Fusarium Wilt Disease on Tomato Plants
Authors: Rachmawaty  , Mu’nisa Andi , Hiola Siti Fatmah , Ali Alimuddin , Hasri
Published: June 2019

The study was conducted to determine the effectiveness of botanical fungicide formulations of cacao pod husk (Theobroma cacao L.) on the intensity of fusarium wilt in tomato plants. The research was carried out at the Biology Experimental Laboratory in Universitas Negeri Makassar, South Sulawesi, Indonesia. The study design used a Completely Randomized Design (CRD) with six treatments, namely KSH (control of health treatment without treatment), KSK (control of sick plants treated F. oxysporum f.sp licopersicy), BSTR (benomyl + treatment of F. oxysporum f.sp licopersicy). EKBK (treatment of cacao pod husk extract + treatment of F. oxysporum f.sp licopersicy). The EKBK treatment used cacao pod husk extract with 3 types of concentration, namely: 2% (v/v); 5% (v/v); and 8% (v/v). Each treatment consisted of 10 replications so that the total number was 60 experiment units. Observations included the number of yellowing and deciduous leaves due to the Fusarium oxysporum attack on tomato plants. The results showed that botanical fungicides from cacao pod husk extract were able to reduce the intensity of fusarium wilt attacks. At a concentration of 2% (v/v) tomato plants that were attacked by fusarium wilt by 54%; concentration of 5% (v/v) of tomato plants attacked by fusarium wilt at 34.5%; and a concentration of 8% (v/v) of tomato plants attacked by fusarium wilt at 23.8%. The results obtained showed that the intensity of the attacks that occurred in the use of botanical fungicides from cacao pod husk extract was lower than the use of synthetic fungicides (benomyl) which was equal to 39.0%.
Factors Affecting the Integration of ICT in Education
Authors: Sokku Saharuddin Ronge , Anwar Misita
Published: June 2019

This study aims to find the factors that influence the integration of ICT in learning by high school teachers throughout Makassar. This study is the result of preliminary research conducted on five schools as a sample. The method is surveyed. Sampling was conducted on 134 subject teachers. The results of this survey show several factors that influence, among others; factors of vision and personal perception, the competence of teachers, lack of time, lack of resources, and lack of electronic-based learning resources.
Antimicrobial and Antioxidant Activities from a Combination of Swietenia mahagoni seed Extract and Virgin Coconut Oil (VCO)
Authors: Hartati  , Idris Irma Suryani , Karim Hilda , Pagarra Halifah , Rachmawaty
Published: June 2019

Abstrak. This study aims to investigation the effect of a combination of Swietenia mahagoni seed extracts with virgin coconut oil (VCO) on antimicrobial and antioxidant activity in vitro. The extraction process was carried out using soxhlet with ethyl acetate solvent. Antimicrobial activity were tested for Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The antioxidant activity combination extracts Swietenia mahagoni and VCO was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The results of the study showed that the combination of S. mahagoni seed extract with VCO at the same ratio were found to be active againts the microbial tested. The combination of S. mahagoni seed extract and VCO similar ratio also showed high antioxidant activity compared to other formulation.
Detection of Cosmic Rays from ground: an Introduction
Authors: Sciascio Giuseppe Di
Published: June 2019

Cosmic rays are the most outstanding example of accelerated particles. They are about 1% of the total mass of the Universe, so that cosmic rays would represent by far the most important energy transformation process of the Universe. Despite large progresses in building new detectors and in the analysis techniques, the key questions concerning origin, acceleration and propagation of the radiation are still open. One of the reasons is that there are significant discrepancies among the different results obtained by experiments located at ground probably due to unknown systematic errors affecting the measurements.

In this note we will focus on detection of Galactic CRs from ground with EAS arrays. This is not a place for a complete review of CR physics (for which we recommend, for instance [1, 2, 3, 4, 5, 6, 7]) but only to provide elements useful to understand the basic techniques used in reconstructing primary particle characteristics (energy, mass and arrival direction) from ground, and to show why indirect measurements are difficult and results still conflicting.
Multi-messenger observations with cosmic rays, gamma-rays and neutrinos, present status and future perspectives
Authors: Semikoz D.
Published: June 2019

In lectures presented at the ISAPP-Baikal summer school I summarised the status and expectations of the multi-messenger astroparticle physics observations using astrophysical neutrinos, cosmic rays and gamma-rays. In this lectures I presented a summary of existing observations as well as an interpretation of the results.
Jet-film contact devices for heat and mass transfer processes in heat power engineering
Authors: Dmitriev A V , Khafizova A I , Dmitrieva O S
Published: June 2019

One of the main production processes for many branches of industry is cooling of recycled\circulating water, which takes place in the cooling towers. The most important parameter to determine the cooling efficiency of water in the cooling tower is the contact surface of air and water. The existing designs of contact devices are highly effective in cooling the liquid, but they are complex to manufacture and expensive. In this regard, a new design of the jet-film contact device was developed, which allows creating a highly developed contact surface of liquid and gas phases. Mathematical model of the element of jet-film contact device was built by means of specialized software package and numerical calculations were carried out. Paper includes the study of behaviour of liquid and gas phases in the device element, and the mathematical dependences were obtained. Dependency of the liquid entrainment from device when changing the water flow rate was studied. Also, the comparison of designs with different location of holes within the wall elements was also carried out. Modernization of the studied jetfilm contact device was carried out in order to identify the direction which to follow for improvement of design properties. This paper proposes an engineering method for calculating the jet-film contact device.
Efficiency of application of various layout arrangements of oil-gas burners in thermal power plant boilers
Authors: Taymarov M A , Akhmetova R V , Akhmetov E A
Published: June 2019

The necessary intensity of burning and completeness of fuel burning out in furnace volume are reached by the correct supply organization and the subsequent mixture of fuel with secondary air that is provided with burner devices. Experimental research of fuel oil and gas combustion efficiency in boiler furnaces of thermal power plant has shown that, the peripheral axial twist executed in the form of two channels with axial scapular air rotator is preferable. The combined gas supply is perspective: tubular peripheral and pilot central. For fuel oil combustion at large expenses the most effective burning is reached due to application of steam-mechanical nozzles which main lack is the considerable length of a torch. The two-tiered arrangement of burners in boiler at combustion of gas and fuel oil is more effective, in comparison with single-tier, both at the counter direction, and at unilateral frontal. For increasing the efficiency of combustion of fuel at some burners types in a boiler furnace the ascending vertical rotation of a torch can be created by the asymmetrical counter arrangement of burners of the first and second tiers. Use of the smoke exhauster of gases recirculation for reduction of harmful emissions of nitrogen oxides with boilers flue gases gives bigger effect in comparison with optimization of the choice of a layout arrangement of burners and parameter of a twist.
Approximate analytical solution to the stationary two-dimensional heat conduction problem on infinite bar with the source of heat
Authors: Tkachev V K
Published: June 2019

An approximate analytical solution to the boundary-value heat conduction problem for an infinite bar with a heat source was obtained with the use of the integral method of heat balance, by introducing a complementary required function and complementary boundary conditions. The boundary - value problem for a partial differential equation is reduced to an ordinary differential equation with respect to this function due to the complementary required function that characterizes the change in temperature along the axis of symmetry in the cross-section of the bar. The complementary boundary conditions determined by the initial differential equation and the given boundary conditions are found so that their satisfaction is equivalent to the solution of the initial equation of the boundary value problem at the boundary points. The fulfilment of the equation at the boundary points as well as the heat balance integral results in the fulfilment of the initial equation inside the domain. The approximate analytical solution obtained can be used to identify the amount of internal heat generated by various production processes (vibration and deformation loads, electromagnetic fields effects, etc.) in thermal and nuclear power plants, in the rocket and space industry and other industrial facilities.
Three-phase current sensor for motor protection against turn-to-turn and phase-to-phase short circuits
Authors: Ishmukhamedov I K
Published: June 2019

The main causes of electric motor failures are transients at power supply interruption and short circuit in stator windings. Most of the failures are due to short circuits. Phase-to-phase short circuits refer to the most severe damage of electrical installations, which are also dangerous for other intact electric consumers. Therefore, electrical plants require a high-speed protection against phase-to-phase short circuits in the stator windings and connections with the commutator. The most difficult to detect are turn-to-turn (or inter-turn) faults in stator windings, especially when a small number of winding turns is shorted. Currently, there is no standard way to detect turn-to-turn short circuits in stator windings. It is difficult to detect turn-to-turn fault in magnitude of phase currents, so it is complicated to provide sufficient protection sensitivity. Thus, the development of new protection devices for detect turn-to-turn short circuit is considered relevant. The article presents a three-phase current sensor based on measuring the magnetic field from the three phases simultaneously. This method will identify turn-to-turn and phase-to-phase short circuits by magnetic-field pattern. The presented method increases the protection sensitivity and speed of protection response. The effectiveness of the proposed method is demonstrated by mathematical modeling.
Adaptive correction of current longitudinal differential protection of power equipment
Authors: Popov M G
Published: June 2019

The report reflects the long-term solutions for the modernization of main means of emergency control and protection of integrated power systems in the implementation of adaptive control algorithms. The substantiation of new structures and algorithms for the formation of corrective signals using non-stationary filters of the displacement current of overhead power lines is performed. Calculated, using the bias currents of the phases are used for dynamic correction of the working and brake signals of the longitudinal differential protection. The basis of adaptive means of differential protection of power equipment of power systems is developed. They are based on the use of adaptive correction of operating and brake protection signals. A mathematical description of the optimization problem of determining the response parameters of sensitive longitudinal current differential protection with adaptive correction of operating and braking signals is performed.
The increasing of the energy efficiency of nuclear power plants with fast neutron reactors by utilizing waste heat using heat pumps
Authors: Kostarev V S , Tashlykov O L , Klimova V A
Published: June 2019

Today, an important task for the economy is to increase the efficiency of using primary fuel. At present, for nuclear power plants with VVER reactors, thermal efficiency is about 33%, with fast neutron reactors - more than 40%. This means that most of the heat produced is released into the atmosphere. In this paper, we consider methods to solve the problem of increasing energy efficiency by the example of NPPs with fast neutron reactors due to the utilization of low-grade waste heat. The results of practical implementation of utilization of low-potential thermal energy of thermal and nuclear power plants using heat pumps were generalized. The analysis of the utilization efficiency of waste heat from various NPP systems was performed.
Improving the efficiency of flue gas desulphurization of TPS
Authors: Rikker Yu O , Kobylkin M V , Batukhtin A G
Published: June 2019

The effects of sulfur oxides on the environment and human health have negative consequences. A significant amount of sulfur oxides is emitted into the air with flue gases from the TPS. Modern Russian TPS are not equipped with sulfur-trapping units due to their significant cost. The study is devoted to the research of low-cost methods that increase the efficiency of the flue gas desulphurisation process at coal-fired TPS. Existing methods are considered from the perspective of the presence of advantages and disadvantages. The potential of the use of purge water from boilers for flue gas desulfurization of TPS.
Parametric optimization of an architectural object’s form as a method to improve its energy efficiency
Authors: Vasilenko N A
Published: June 2019

Parametric optimization of an architectural object’s form is one of the design tasks, which architects and project designers face at the stage of structural concept development and design. Improving the performance qualities of a design solution, while providing its energy efficiency, is the purpose of system research in the sphere of architecture and urban planning. The article gives the comparison of calculated compactness ratios of the external envelope for one-, two- and three-, four-, five-, six-, seven-storey 6-apartment compact-form residential houses, comparable in the floor surface area criterion. The application of BEM software packages on the basis of BIM-modeling of buildings is reasonable to substantiate with the optimal functional (consumer) properties of an architectural object. Systematic methodology allows considering the architectural and design problems in the interdisciplinary way. Computer modeling of architectural objects should solve the optimization tasks on the basis of version design and contain an optimization module, which would allow taking the optimal decision at the specified design constraints (conditions) and normative parameters. Computer modeling of architectural objects with the use of structural optimization methods for the version design is a promising area, which requires the formalization of project procedures and developing automated design system tools for designing buildings of various purposes.
Development and research of low pressure injection burner for biogas combustion
Authors: Suslov D Y , Ramazanov R S , Temnikov D O , Lobanov I V
Published: June 2019

The article is dedicated to the problem of using an alternative energy source – biogas in gas supply systems. A low pressure injection burner with a conical shaped heat diffuser has been designed. A diffuser placed in the burner body provides preheating of the gas-air mixture and allows to increase a flame propagation velocity. A computer simulation of the gas-air mixing process in a body has been made for 3 types of burners: without a diffuser, with a diffuser of 11 mm and 25.5 mm long. As follows from the simulation, 11mm diffuser has no adverse effect on the gas-air mixing process. While an increasing length of the diffuser up to 25.5mm leads to the decreasing cross-section area of a mixing chamber, therefore increasing air-gas mixture rate and methane concentration in the flame holes. Experimental tests have been performed in relation to biogas combustion process for those 3 types of burners. Experimental results proved that placement of 11mm diffuser in a burner body reduces the time for heating water in the tank up to 100°C by 6% (45.41 s). 25.5 mm diffuser reduces the heating time by 1.5% more (11.37 s). Thus, we can make a conclusion that the presence of a diffuser in the burner body increases a flame propagation velocity and a heat rate of the burner.
Analysis of the environmental factors influence on the efficiency of photovoltaic systems
Authors: Zatsarinnaya J N , Amirov D I , Zemskova LV
Published: June 2019

The development of civilization is associated with the creation of various methods of energy conversion. Humanity has come a long way from the water wheel to modern power plants. Though earlier people did not think about the damage to the environment from the work of a number of power plants, today this cannot be ignored. Renewable energy sources (RES) and their using by modern technologies claim to play a significant role in the world energy sector. Support for the development of RES in Russia is currently based on compensation of costs under contracts for the sale of power in the wholesale electricity and power market. According to the results of the competition of the Trading System Administrator, projects under the contracts for renewable energy power supply selected. Analysis of bids of the Trading System Administrator (TSA) showed that until 2023 will be introduced 1.8 GW of solar power plants, so the actual goal will be the correct operation of them in the weather conditions of Russia. Pollution of various types, which can be on the panels can affect the operation of solar panels (SP) and prevent the ingress of solar radiation on them. The article investigates the influence of various types of pollutants on the power generated by solar panels and promising places for the construction of solar plants in the climatic and geographical conditions of Russia, taking into account possible polluting factors, which can lead to total economic damage of up to 15 million rubles per year.
Optimization of power output for a wind turbine using methods of artificial intelligence
Authors: Zubova N V , Rudykh V D
Published: June 2019

Percentage of wind energy in worldwide power generation increases year after year. At the present time, problems of increasing the energy efficiency of wind turbines (WT) and optimization of WT power output are of great importance due to instability of wind energy. It stimulates the development, investigation and using of intelligent systems for controlling operating regimes of wind turbines. Such systems also involve those systems that are developed using algorithms based on fuzzy logic. This paper presents the results of investigations devoted to searching for optimal membership functions for fuzzy sets of input and output variables. These variables and membership functions are used in fuzzy algorithms developed for enhancing power output of wind turbines under the given operating conditions. After analyzing the obtained results, it may be concluded that the use of symmetrical Gaussian membership functions gives the fastest convergence of the optimal power into the point.
Effect of aluminum additives on the ignition of tungsten–teflon mixtures
Authors: Alymov M I , Vadchenko S G , Gordopolova I S
Published: June 2019

Thermodynamic analysis and studies of combustion and structure formation of products were carried out in the powder mixtures of tungsten and polytetrafluoroethylene (Teflon, Tf) with aluminum additives. The mixture components were selected to fabricate high-density condensed products with high ignition temperature. Aluminum was used as an energetic additive accelerating the ignition process and increasing the mixture combustion temperature. In mixtures, a tungsten/Tf ratio was fixed; the aluminum content was varied according to the formula (1 − x)(0.8W + 0.2Tf) + xAl = const. Mechanically activated mixtures were pressed into the samples and heated in special crucible with controlled heating rate. It was shown that an increase in the heating rate changes insignificantly the ignition temperature of systems, but strongly affects the structure of combustion products. The ignition and combustion of compositions with low aluminum content results a large volume of gaseous products, which fly apart or form a high-porous structure. At high Al concentration, the results of experiments and thermodynamic calculations are sufficiently different that can be explained by the lack of thermodynamic data on tungsten aluminides in the used program and by the fact that real conditions of reaction are far from equilibrium and adiabatic ones. The calculated and experimental data showed that the optimal aluminum content to form melted products with a high density (ρ(W2C) = 17.2 g/cm3) is about 10 wt %. At high Al concentration, the main combustion product (tungsten aluminide WAl4) has the lower density (ρ(WAl4) = 6.6 g/cm3) that is insufficiently for practical application.
X-ray powder diffraction analysis of a tungsten carbide-based ceramic
Authors: Andreev P V , Smetanina K E , Lantsev E A
Published: June 2019

The results of the qualitative and quantitative X-ray powder diffraction analysis of the W–C system samples are presented. Powder samples were nanopowders of α-WC/W2C obtained by plasma chemical synthesis. High-density fine-grained structure of ceramics was formed using the method of electro pulse plasma sintering (spark plasma sintering) from the initial powder of the α-WC. The optimal experimental conditions for the X-ray diffraction proceeding of the tungsten carbide based ceramic samples were chosen according to the preliminary experiments. Reference intensity ratio method for quantitative phase analysis was used in this study.
Application of the “Brazilian test” to determine the strength of materials obtained by electric pulse consolidation of powders
Authors: Goltsev V Y , Grigor’ev E G , Gribov N A , Osintsev A V , Plotnikov A S
Published: June 2019

Testing of short cylinders according to the “Brazilian test” scheme is considered as a method of assessing the tensile strength of brittle materials obtained by electric pulse
consolidation of powders. The paper presents a calculated using FEM and an experimental analysis of the behavior of short cylinders (thick disks) when loaded according to the “Brazilian test” scheme. The calculation shows the weak influence of the disk thickness on the average and maximum tensile stresses in the plane of symmetry of the disk. Results of testing of small samples made of cast iron and graphite are presented. It is shown a good correspondence between the results of the test samples from cast iron when using formula recommended by the ASTM Standard D3967-95a, and the strength of the material when tested in tension. The results of testing samples of graphite were 1.5–2 times less than its tensile strength. The results of testing of small-size samples of heavy alloy WNiFe and aluminum oxide obtained by electric pulse consolidation of powders are presented. The influence of the pressure and current pulse on the fracture resistance of the alloy WNiFe and the sample thickness on the strength of Al2O3 is investigated. Thus, the possibility of testing small samples according to the “Brazilian test” scheme to determine the tensile strength of materials obtained by electric pulse consolidation of powders is demonstrated.
Refractory and heat-insulating materials based on aluminosilicate SHS compositions
Authors: Kapustin R D
Published: June 2019

The phase composition, structure, and physical and mechanical characteristics of refractory aluminosilicate SHS materials (AS materials) were investigated taking into account the properties of initial components and the production method. Computational methods were used to reveal macrokinetics of processes and determine the possible formation of mullite structures and corundum in aluminosilicate refractory SHS materials during the synthesis reactions. Heat losses caused by the small thickness of a coating or the walls of the material between pores were found to have a significant effect on the synthesis reaction in thin coatings and porous AS materials, as well as the on the formation of various chemical compounds.
Synthesis of Ti2AlN MAX-phase by sintering in vacuum
Authors: Kondakov A A , Studenikin I A , Linde A V , Kondakova N A , Grachev V V
Published: June 2019

The dependence of MAX-phase synthesis on phase composition of the initial mixture and heat treatment terms in the electric furnace was investigated. Using Ti and AlN powders with the molecular ratio 2:1 as an example, the sequence of phase composition changes with increasing exposure temperature was tracked. It was established that the maximum amount of Ti2AlN MAX-phase in the end products is obtained at 1400°C. At this temperature a single phase product (100% wt Ti2AlN) was obtained for the initial mixture Ti:Al:TiN = 1:1:1. The principal possibility of scaling for obtaining a single-phase product of Ti2AlN by vacuum sintering was experimentally shown on the example of the mixture of this composition weighing 500 g at a certain mode of thermal vacuum treatment.
Synthesis of nanopowders of titanium compounds via Flow-Levitation method and study their properties
Authors: Kuskov M L , Zhigach A N , Leipunsky I O , Afanasenkova E S , Safronova O A , Berezkina N G , Vorobjeva G A
Published: June 2019

Nanopowders of titanium compounds TiH2 and TiC are synthesized via Flow-Levitation method using in situ reaction of nascent titanium nanoparticles with the proper reactants. The influence of manufacturing parameters on the composition and the internal structure of the synthesized nanoparticles is examined. Study of TiH2 nanoparticles using thermal methods revealed hydrogen evolution within the narrow temperature range (390-510°C), while hydrogen evolution temperature of the commercial samples is higher than 500°C.
Synthesis and investigation of highly transparent ceramics
Authors: Osipov V V , Shitov V A , Platonov V V , Maksimov R N , Lukyashin K E
Published: June 2019

A short review of research works carried out in the Institute of Electrophysics UrB RAS on the development of synthesis technology for laser ceramics and the analysis of their characteristics is presented. These ceramics are widely used as active media of solid-state lasers, transparent armor, envelopes of high intensity discharge lamps, heat-resistant and mechanically strong windows etc.
Features of interaction of powder high-velocity particles with the surface layer of the target
Authors: Petrov E V
Published: June 2019

The interaction of a stream of high-velocity particles with the surface layer of a target was investigated. The impact of discrete particles with the sample surface was shown to lead to the formation of a coating consisting of these particles and to the changes in the physical and mechanical properties of the surface layer of the target. The obtained coatings are a composite material consisting of sintered (not melted) powder particles. The impact of high-velocity particles was shown to lead to the hardening of the surface layer of samples exposed to the stream of powder particles of tungsten, nickel and titanium nitride. The maximum increase in the microhardness of targets was observed at a depth of 2 and 4 mm from the surface treated with a stream of particles.
Mechanical activation of metallic powders in planetary ball mills: multi-scale modeling and experimental observation
Authors: Politano O , Fourmont A , Gallet S Le , Baras F , Nepapushev A A , Sedegov A S , Vadchenko S G , Rogachev A S
Published: June 2019

Ball motion and microstructure formation in the mixtures of Al with metals (Ti, Ni) during high-energy planetary ball milling are studied by means of high-speed video recording, scanning electron microscopy and computer modeling, including molecular dynamics simulation. Possibility of production reactive composite powders with rounded particles for using in selective laser melting techniques has been demonstrated.
Applicability of molecular dynamics method to the prediction of the melting point of refractory metals and compounds
Authors: Rogachev S A
Published: June 2019

Various methods for measuring the melting point using embedded atom model (EAM) and from first principles modeling are considered. The features of each of them are shown. The results of the work of these methods are compared with the experimental values on the example of systems consisting of pure metals such as Fe, Pd, Ti, Pt Zr, Mo, Ta, W. Good agreement of the estimated melting points with experimental values is shown.
Nanostructured Cu–Cr–W pseudoalloys by combined use of high-energy ball milling and spark plasma sintering
Authors: Shkodich N F , Kuskov K V , Kovalev I D , Scheck Yu B
Published: June 2019

Nanostructured pseudoalloys of immiscible Cu, Cr and W metals were prepared by combined use of high-energy ball milling (HEBM) and spark plasma sintering (SPS). Mechanical alloying in an Activator-2S planetary ball mill for 150 min provides a uniform distribution of refractory Cr and W particles in a moldable Cu matrix on a submicron and nanoscale level. Activated W–Cu–Cr powders were SPS-consolidated at 800−1000°C and 50 MPa for 10 min. The effect of preparation conditions on the microstructure, crystal structure, and properties (density, hardness, electric resistivity) of synthesized nanostructured W–Cu–Cr pseudoalloys was studied. The consolidated W–Cu–Cr composites showed a hardness of up to 9.5 GPa and an electric conductivity of 27–28% IACS, which makes them promising for use as an interrupter contact material.
Morphology and phase composition of hybrid powders based on aluminum, synthesized for a gas-dynamic spraying of coatings by milling
Authors: Sobol’kov A V , Aborkin A V
Published: June 2019

Hybrid powders of the AlMg2 + 1 wt % TiC/MWNT + 10−50 wt % Al2O3 system were obtained using the method of mechanical processing in a planetary ball mill. The powders were characterized using the methods of scanning electron microscopy, particle size distribution testing and X-ray analysis. It is shown that an increase in the content of Al2O3 particles from 10 to 50 wt % leads to a decrease in the average particle size of the synthesized powder from 49 to 16 μm, respectively. The proportion of particles smaller than 5 μm, depending on the concentration of Al2O3, varies in the range of 1.2−15.1%. At the same time, the size of the matrix material crystallites decreases from 58 and 52 nm, respectively. The resulting hybrid powder can be used to create functional coatings using cold gas-dynamic spraying.
Dynamic Mechanical Properties of Magnetorheological Elastomers: Experiment and Modelling
Authors: Zhu G H , Li Z G , Xiong Y P , Xiao L , Li M
Published: June 2019

As a kind of smart material, magnetorheological elastomer (MRE) is composed of magnetizable particles dispersed in an elastomer matrix. Because adjusting an external magnetic field can continuously, rapidly and reversibly control the dynamic properties, there has been increasing research on MRE for mitigation of unwanted vibrations. In this paper, the dynamic mechanical analysis tests were performed to investigate the influence of strain, frequency and magnetic field on the controllable dynamic properties. The storage modulus and loss modulus of MRE were analyzed with frequencies from 1 to 50 Hz, strain amplitudes from 1 to 6% and magnetic field intensities from 0 to 500 mT. The results show that the storage modulus decreases with increasing strain amplitude, increases with frequency and magnetic strength, and remains constant when the magnetic saturation occurs. Furthermore, the dependence of loss modulus on frequency lies on the matrix material of MRE. Based on the experimental results, a fractional derivative model was developed to describe the viscoelastic properties and the controllable dynamic properties. The comprehensive study of mechanical property characterisation is a guarantee for constitutive models to accurately describe the dynamic behaviour of MRE, which is an essential step towards the application for vibration control.
Development of High Performance Grouting Method for PSC Strands
Authors: Yoon In-Seok , Kim Joo-Hwan , Jeon Min-Jin , Jang Seoung-Hwan
Published: June 2019

Prestressed concrete is very vulnerable to corrosion of strand because it has already been subjected to high tensile stress. The stability and durability of PSC have a very important relationship. In this study, many grouting specimens was made and the grouting performance used in the post tensioning construction fields were evaluated by the electrochemical method and weight loss measurement. The corrosion test was carried out in accordance with modification based on PTI M55.1-12 specification. Corrosion was activated by two types: corrosion by chloride ion (Cl−), and corrosion by chloride ion and dissolved oxygen (Cl− + DO). The results showed that polymer is useful to maintain structural stability by reducing deterioration due to strands corrosion in PSC