bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulsed electric discharge in an aqueous medium for processing raw amber
Authors: Martynov N , Avramov D , Kozlov G , Pushkarev M
Published: September 2020

The paper presents the results on the use of pulsed electric discharge in an aqueous medium (Yutkin effect) for processing raw amber. The proposed method allows to achieve a high degree of purification of the surface of amber, including purification from the oxidized crust, almost without destruction of the original pieces, while there is no sticking of small fractions and other negative phenomena. Using the same method, but in other treatment modes, it is possible to crush off-grade feedstock for further refining. Fractional composition of the obtaining material and the degree of its purification are regulated by the treatment mode. So three technological processes (washing, peeling and crushing) can be carried out using only one installation, which significantly reduce the cost of industrial implementation.
The periodic temperature oscillations in the near-surface layer of cylindrical structures
Authors: Samarin O D
Published: September 2020

A hollow cylinder with thick walls and linear continuously acting variable heat sources are among the most difficult objects to calculate the unsteady temperature field, so this field is the least studied. However, such objects are found in many modern designs of heat generation and distribution systems. The proposed work considers the study of the temperature wave propagation in the wall of a hollow cylinder and in a cylindrical symmetric array around a variable linear heat source with a harmonious change in the temperature of the external or internal environment that occurs during its daily fluctuations or when regulating the heat distribution system. The result of approximate analytical solution of the problem by the method of separation of variables in the complex domain using cylindrical functions is presented. The data of numerical calculation of attenuation of temperature oscillations in the near-surface layer of the cylinder and around the variable linear heat source by means of an explicit finite-difference scheme of increased accuracy under boundary conditions of the first kind and their comparison with the analytical solution for its refinement are presented. The refined analytical dependences for the attenuation coefficient of the temperature wave suitable for use at low thermal inertia of the cylindrical layer and giving physically correct results at the boundary values of the parameters are proposed. The difference in the nature of the damping of oscillations in the direction of the temperature wave outside and inside the cylinder is noted. The presented dependences are proposed to be used for a refined analytical assessment of the amplitude of temperature fluctuations in the near-surface layer of cylindrical heated structures and around the heating and heat supply pipelines in variable modes, which will allow the use of engineering methods to verify compliance with the requirements of industrial safety.
Calculating the load on the room cooling ceiling panel at solar heat gains
Authors: Malyavina E G , Lomakin A G
Published: September 2020

It is known from the theory of heat exchange that for the assimilation of the room heat gains that are not constant in time, a cold flow of the same nature that assimilates them must be equal to them in magnitude. This is obvious with respect to convective heat gains that introduce directly into the air. The case is more difficult with the radiant heat gains, since the incoming radiant flow can be directed to one surface, and the assimilating one comes from another. The article aims to check to what extent this provision plays a role in the realities of maintaining a given room microclimate. However, in engineering practice, there are no purely radiant heat assimilating systems. Therefore, as a room cooling system, a ceiling cooling panel has been used, the heat flow from which is of a radiant-convective nature. The radiant load of the room occurred from the solar radiation, penetrating through the windows of various orientations on the cardinal directions. Determination of the load on the cooling system was performed by calculation. Based on the results of the calculation, it was found that the load on the ceiling panel significantly depends on the internal heat stability of the room.
Elastomeric fire and heat-protective materials containing zirconium dioxide
Authors: Kablov V F , Novopol’tseva O M , Kryukova D A , Antonov Y M , Kochetkov V G
Published: September 2020

Elastomeric fire-protective materials are widely used to protect special-propose structure in rocket, aviation and marine equipment. Important parameters of such materials are density and thermal conductivity. The reduction of these indicators while maintaining the rest of the set of materials properties is a complex and multifactorial task. A promising direction of its solution is the use of microspheres. The work shows that it is possible to increase the fire protection efficiency of elastomeric compositions, which contain transition metal oxides, with zirconium dioxide as an example. The effect of the introduction of zirconium dioxide in the form of a microdisperse powder, microspheres, and zirconium-aluminosilicate microfibers on the physical and mechanical, thermophysical, and fire protective properties of elastomeric compositions based on ethylene propylenediene rubber has also been considered.
Thermotechnical calculation of enclosing structures of a standard type residential building
Authors: Gamayunova O , Petrichenko M , Mottaeva A
Published: September 2020

Russia has extensive experience in the design and construction of typical series of residential apartment buildings. When there is a library of standard projects for which additional expertise is not required, this significantly reduces both the price and the construction time of the facilities. Accordingly, the cost per square meter is reduced. Currently, to reduce the cost of construction, some developers use enclosing structures made of materials with high thermal conductivity, thereby reducing the energy efficiency of buildings and structures. In this article, on the example of houses of mass series 1-447, the thermotechnical calculation of enclosing structures was carried out and the option of the optimal position of the insulation was determined. The temperature distribution of the building envelope is presented.
Studies of Freon mixture separation using a large-scale model of distillation column
Authors: Pavlenko A N , Zhukov V E , Slesareva E Yu , Boyadjiev Chr , Dzhonova-Atanasova D
Published: September 2020

The operation efficiency of distillation columns with structured packing is maximal if the distribution of countercurrent vapor and liquid film flows over the column cross-section on the mass transfer surface is most uniform. Various types of structured packing are widely used in distillation columns. Formation of the temperature field maldistribution in the column cross-section is observed in large-scale distillation columns. The sizes of large-scale maldistributions on zones are commensurate with the column diameter. The aim of this work is to obtain experimental data on the separation efficiency in large-scale distillation columns and dynamics of formation of large-scale maldistributions of local parameters of vapor and liquid in a countercurrent flow over a structured packing during mixture separation. Separation of the R114/R21 freon mixture was carried out on a structured Mellapack 350.Y packing with a diameter of 0.9 m and height of 2100 mm. The experiments were carried out under conditions of complete reflux in the range of reduced vapor velocity of 0.017 < K
v < 0.035 m/s. Experimental data were obtained on the efficiency of mixture separation, pressure drop over the structured packing and parameters determining the formation dynamics of the large-scale temperature field maldistribution in the column cross-section. The presented experimental data will be used for the construction and verification of a new model of mass transfer and efficiency of mixture separation in large-scale distillation packed columns.
Modernization of the heat pump installation for drying wheat
Authors: Kizurov A S
Published: September 2020

The most energy-consuming and most critical stage of post-harvest processing is grain drying. Safety of grain depends on its drying. For drying grain, grain drying plants are used that remove excess moisture from the grain. In most cases, drying occurs under the influence of elevated temperatures with a constant supply of heat. After drying, the grain must be cooled to eliminate irreversible processes. The drying process is slow due to temperature limitations. To speed up the drying process, various techniques are used, one of which is the alternation of heating and cooling processes (differentiation of heat input). To increase the drying energy efficiency in the conditions of differentiation of the supply of thermal energy, it is advisable to use heat pump units. Heat pump units allow the creation of a heating agent (heated air) and a cooling agent (cooled air). Studies have shown that for different grain parameters, different temperature characteristics of heating and cooling agents are required. For independent temperature control of heating and cooling agents, an original design of a heat pump installation has been developed. To automate the control of the drying process, several control schemes have been developed and investigated.
Modeling the change of water content in wood at atmospheric drying
Authors: Zaitseva M , Nikonova J , Kolesnikov G
Published: September 2020

Objective: to develop a methodology for predicting changes in the water content in wood during atmospheric drying, taking into account the fast and slow stages of this process. Research methods: mathematical modeling, applied analysis of results, comparison with experimental data known from the literature, synthesis in order to better understand the regularities of drying. Results: a two-parameter model is developed, in which a phenomenological approach is used, focused on obtaining averaged estimates of wood moisture during atmospheric drying. Causal relationships are not detailed, but are taken into account in an integral form. Calculation formulas are obtained, the use of which simplifies the procedure for predicting changes in the water content in wood during atmospheric drying. The adequacy of the model and the reliability of the calculation results are confirmed by their consistency with the experimental data known in the literature. Research prospects can be focused on adapting the model to other drying methods in order to reduce the energy and time spent on a given technological process.
Characterization of rainfall events corresponding to forecasted conditions of potential hydrogeological risk
Authors: Khramtsova L , Leonteva M , Mobilia M , Longobardi A , Nasyrova E , Aksenov S
Published: September 2020

The Italian territory has a high exposure to natural risks including floods and landslides. An early warning system run by the Department for Civil Protection, both at national and regional level, operates to forecasted conditions of potential hydrogeological risk on the basis of forecasted meteorological conditions. The aim of the present paper is to study the relationship between the level of alert issued by the Civil Protection and the characteristics of the associated rainfall events. The case study is a particular area of the Campania region, highly prone to hydrogeological risk. A database of 138 warnings issued during the period 2018-2019 has been analyzed. The warnings were classified using analytical and graphical methods with various criteria. The duration, total rainfall, peak intensity, return period, n-index, BSC-index were used. The results show that there is a clear correlation between the severity of the warnings and the cumulative, peak intensity and the structure of precipitation. No relationship has instead been found between the severity of the warnings and the severity of the rainfall event which, besides the limitation of the case study with a small sample of analyzed events, can be an indication of changing climate conditions.
Comparative analysis for three models of hysteretic water retention capacity using data on silty soil
Authors: Lazarev V A , Ginevsky R S , Topaj A G , Nikonorov A O , Dunaieva I A , Terleeva A V
Published: September 2020

The most important of the hydrophysical properties is the water-retention capacity of the soil. This property is formulated as a relationship between the volumetric moisture of the soil and the capillary pressure of soil moisture. Three hysteresis models of soil water-retention capacity are presented. The parameters were identified by point approximation of experimental data (from an authoritative literary source) on the main (boundary) drying and wetting branches of the soil «2003 Silt of Nave-Yaar» using the «SoilHysteresis-v.1.0» computer program developed by the authors. Applying the condition of equality of the values of the exponential parameter for the branches of draining and moistening eliminates the undesirable (methodical) «pump effect». A comparative analysis of hysteresis models based on the identification of significant differences between the errors of the point approximation of the experimental data by the Williams-Kloot test. The advantages of models in which an additional additive parameter is used are revealed. The use of physically justified models of hysteresis of the water-retention capacity of the soil has prospects in the development and application of resource-saving technologies in precision reclamation agriculture.
The effect of snow covers properties and air temperature on the ice freezing thickness near Yakutsk
Authors: Frolov D
Published: September 2020

This study is devoted to the possible Yakutsk Lena–river automobile and railway bridge construction and estimation of icing and ice blockage formation possibility variation. So, according to developed algorithm and calculating scheme the calculations of ice freezing thickness variations for observation site of Yakutsk Lena-river hydrological station were performed on basis of meteorological data on air temperature and snow cover thickness for winter periods of 1980/81-2018/19. The comparison of calculated and available in open access observation data on ice freezing thickness for these winter periods was also conducted and the coefficient of correlation of equal 0.7-0.8 for them was stated. The calculating scheme for ice freezing is constructed on basis of two-layer media heat conductivity problem (snow cover, ice) with phase transition on the boundary of ice and unfrozen water. Heat balance equation includes phase transition energy on the interface and outflow of heat through ice and snow cover into the atmosphere. The heat flux is calculated on basis of Fourier law as a product of heat conductivity and temperature gradient. It is supposed, that temperature changes in each media linearly.
Modeling static characteristics of angular velocity measuring transducer of the “nozzle-damper” type
Authors: Golubovsky V , Konovalov V , Doncova M
Published: September 2020

The article describes the design and principle of operation of the hydraulic measuring transducer of angular velocity of the “nozzle-damper” type. The aim of the study is the mathematical modeling in the MathCAD program of the static characteristics (flow and differential) of the measuring transducer, based on the Bernoulli equation. The research methodology provides a theoretical justification of the proposed expressions describing the operation of the transducer, analysis of numerical results obtained by numerical modeling in the MathCAD program, and their verification by comparison with experimental data. The developed mathematical model based on the Bernoulli fluid equation of motion, taking into account the use of the proposed correction factors, allows one to adequately describe the static characteristics of the angular velocity measuring transducer of the “nozzle-damper” type. According to the numerical values of the statistical criteria, the proposed power-law model more accurately describes the experimental data than the linear model. At a supply pressure of the measuring transducer equal to and less than 0.5 MPa, a discrepancy between the results of the model and experiments is observed.
Development of an automatic method for determining vehicle dimensions through computer vision
Authors: Baytesh K , Gematudinov R G , Chantieva M E , Dzhabrailov K A , Gorodnichev M G
Published: September 2020

This article has a system of automatic weight and dimensional control (weight - and - motion), which allows weighing, measuring geometric characteristics, as well as recognition of state registration plates, passing vehicles without stopping, as well as processing of this data and registered violators. The focus is on the work of measuring the mass along the axes. All conversions are performed on the National Instruments multifunction board, which has a microcontroller, additional I/O peripherals field-programmable gate array, which means user-programmable gate arrays. In a more general case, they are called FPGAs - programmable logic integrated circuits. This study is important because heavy vehicles smash federal and local roads. Therefore, it is necessary to control the passage, however, now this measurement is carried out only in static mode. Measurement of dimensions in dynamics based on piezoelectric elements has an error unacceptable by the legislation of the Russian Federation. The developed method will increase the accuracy, which will lead to a mass measurement of dimensions, and will allow to maintain in good condition the roads of federal and local destination.
Modeling the stress state of a rotating flexible thread (cable) to optimize its speed
Authors: Tarasov D , Konovalov V , Zaitsev V
Published: September 2020

The aim of this work was to develop and verify the operability of the method to determine the maximum permissible rotation frequency of a flexible thread (cable), at which a centrifugal inertia force arises, causing stresses and strains not exceeding the permissible limits. Based on the selected assumptions, the research methodology provides for the development of a method of analytical strength calculation of a rotating cable. The resulting system of expressions is the basis for the development of a computer program to be checked for operability by the accuracy of calculations. The calculation method, reflected in the form of a flowchart and implemented as a computer program, allows determining the maximum possible frequency of rotation of a cable that does not allow its limit state to occur, which will simplify the search for the optimal solution and reduce the time spent. Solving the nonlinear programming problem of determining the frequency of rotation of a cable taking into account the development zone of plastic strains in the material at the given maximum permissible stresses and strains by reducing it to the problem of unconditional optimization using Lagrange multipliers allows us to calculate with an error of not more than 4% compared with the FEM. The calculation results make it possible to use the proposed method both when there is a restriction on the strength condition (allowable stresses) of the material of the cable, and on the allowable deflection in the middle of the span of the cable.
Verification of the iterative procedure for solving the elastoplastic Kirsch problem on the Lame problem
Authors: Bukhalov V I , Popov A L
Published: September 2020

An iterative procedure for solving the elastoplastic Lame problem was proposed to further develop an iterative solution of the elastoplastic Kirsch problem. A ring under an external pressure is considered at which a certain plastic zone arises in the ring. The proposed iterative procedure for solving the elastoplastic Lame problem consists in an explicit analytical representation for stresses in the plastic region and the iterative technique for an elastic analytical solution. Furthermore, the plastic zone radius is beforehand unknown. The convergence of the iterative procedure for the elastoplastic Lame problem is shown in comparison with well-known analytical solution to this problem in elastoplastic formulation. A numerical-analytical iterative solution of the Lame problem in elastoplastic formulation is given for various external pressure and internal radius of the ring. Shows the convergence of numerical-analytical iterative solutions the problem in comparison with numerical solutions in elastoplastic formulation.
On estimates of computational complexity and error of the fast algorithm in the vortex methods
Authors: Kuzmina K S , Moreva V S
Published: September 2020

One of the efficient ways to speedup calculations in the vortex method, namely the Barnes – Hut-type algorithm, is considered. This method is based on the introducing of a hierarchical structure of domains (binary tree), which allows one to take into account approximately mutual influences of clusters of vortex elements located far from each other when calculating convective velocities. Estimates of the computational complexity of the algorithm for convective velocities calculating are derived, as well as estimates of the error, which depend on the parameters of the algorithm. In practice, these estimates make it possible to choose optimal values of the algorithm parameters and to achieve the maximal speedup of calculations at a given level of acceptable calculation error.
Qualitative assessment of passenger service
Authors: Anikin N , Terentyev V , Andreev K , Shemyakin A , Martynushkin A
Published: September 2020

The developed methodology for assessing the level of quality of passenger service presented below is relied on existing developments in this area, international standards for determining the quality of service and passengers’ questionnaire. The main goal of the proposed methodology is to determine the necessary social effect of the urban passenger transport, as well as the costs that must be incurred to ensure it and the income that will be received at a given level of service for the population of the city (region). When determining all these indicators, it is necessary to take into account the interests of all participants in the passenger service market (urbanities, owners of private motor transport enterprises and passengers). According to the methodology, it is proposed to determine the social effect of the urban transport through the level of quality of passenger service. This indicator should include both the qualitative characteristics of passenger service and the level of transport tariffs of different carriers, since for many categories of passengers, the latter indicator will play a decisive role in choosing the type of the vehicle and the carrier.
The effect of networks cracks on the strength of pavement
Authors: Rudgalskiy P , Chusov V , Aleksandrova N
Published: September 2020

The analysis of the methodology for determining the coefficient of strength of pavement, based on the results of a visual assessment of the condition of pavement is performed. The traditional classification of the networks of cracks is considered, and the reasons for their arising on the Bolshie Uki - Znamenskoe road are analyzed. Traditional fatigue cracking and temperature tensile stresses are defined as main causes of cracks network. The feature of the emergence of networks of cracks on the pavement of the road Bolshie Uki - Znamenskoe, which consists in the appearance of these defects in sectors located on terrain with long standing groundwater, is revealed. Therefore, as a related cause of the appearance of a network of cracks, the effect of insufficient strength of a subgrade of cohesive soils and increased humidity was noted. Experimental work was carried out to determine the elastic deflections in the sectors with networks of cracks and the reference sector without defects. According to the experimental work, safety factors are determined, and mathematical models of the dependence of the coefficient of strength from the cell size of the cracks network are developed.
Series of split silencers for ventilation systems
Authors: Plitsyna O V , Rogova T N
Published: September 2020

The paper is devoted to the prospects of noise reduction in ventilation systems with large cross-section main air ducts. The design schemes of a split silencer for various systems obtained as a result of calculations and experiments are proposed. For a silencer whose split ducts are formed by successive narrowings and expansions the parameters ensuring minimum noise reduction of 7.5 dB and pressure loss of up to 120 Pa are shown and the recommendations for usage in systems where two-phase flows propagate are given. For a silencer whose split ducts contain internal elements the parameters that provide a minimum noise reduction of 10 dB and pressure loss of up to 90 Pa are identified and the recommendation for usage in supply ventilation systems with the required disinfection is presented. For a silencer that combines two sections with oppositely oriented split ducts its applicability in systems without aerodynamic restrictions and with increased acoustic requirements was noted. For additional silencer section composed from Helmholtz split resonators the parameters that ensure even noise reduction are shown and the recommendation for usage in systems without restrictions on the length of the main duct and with increased low-frequency noise reducing requirements is given.
Improving special motor vehicle internal combustion engines to raise environmental safety
Authors: Kondratyuk A A , Evtyukov S A , Vorobev S A
Published: September 2020

The paper presents the results of theoretical and experimental studies of the environmental characteristics of internal combustion engines for commercial and public motor vehicles operating on the Diesel cycle using a hydrogen additive. An analysis of literary sources confirmed that there are different data on harmful emissions when using a hydrogen additive for internal combustion engines operating on the Diesel cycle. The results of theoretical and experimental studies of the environmental characteristics of internal combustion engines for commercial and public motor vehicles operating on the Diesel cycle using a hydrogen additive suggest the adequacy of the built model, since the error between the theoretical and experimental data did not exceed 14.5%. It was found that the concentration of NOx emissions in an internal combustion engine using a hydrogen additive operating on the Diesel cycle decreased by 52%. The above research results confirm the prospects for the use of hydrogen additive for internal combustion engines operating on the Diesel cycle, which was first used for commercial and municipal motor vehicles. It guarantees improved environmental safety in urban agglomerations.
Development of the non-destructive monitoring methods of the pavement conditions via artificial neural networks
Authors: Elshamy M M M , Tiraturyan A N , Uglova E V , Zakari M
Published: September 2020

Non-structural parameters like surface defects and ride quality were frequently used, as a practical index for the rehabilitation selection process. The key purpose of this study was the assessment of using artificial network technology as a support for decision-makers about paving maintenance concerning the structural condition compared to the conventional, time-consuming, effort, and costly methods. The structural model was established based on the deflections from the FWD, (asphalt and base) layers thickness, surface temperature, precipitation rate, AADTT, traffic volume of class 9 and base layer type. The data used in building the developed ANN model is related to a previous study of flexible pavement structures on the M4 highway in the Russian highways network during the five years 2013-2017. The ANN model was built, trained, and tested by the Matlab program. The focus was on calculating roughness, fatigue, and rutting values as they are the most common pavement distress on site. We used the logistic model equations, developed by the Federal Highway Administration’s Long-Term pavement Performance (LTPP) to calculate the three pavement distress that will be used as output variables while training the ANN model. The ANN model presented a high performance in predicting the three pavement distress (fatigue, roughness, and rutting) where the R- squared value was equal (1, 0,999, and 1), respectively for the forecasting sections.
Conditions modelling of low-temperature cracks existence in the road upper layer
Authors: Gavrilov T , Kolesnikov G
Published: September 2020

Cracks, including low-temperature cracks, reduce to the greatest extent road surfaces quality, increase the cost their repair. This problem is most relevant in the regions with seasonal soil freezing. The purpose of this study is to develop a model of interaction between the asphalt concrete layer and the underlying layer by means of friction and adhesion forces at a negative temperature, also the analyze the conditions low-temperature cracks formation of in the asphalt concrete layer, in order to reduce the risk of cracking. Methods: as a research tool used numerical methods of structural mechanics. Results: the study found that the distribution of tensile forces in the segment of an asphalt-concrete layer is approximated by a polynomial of the second order with a maximum in the middle of the length of the segment. Shear forces are unevenly distributed along the length of the segment; the intensity of the shear forces is equal to zero in the middle of the length of the segment. The greatest shear strains and stresses are localized near the transverse boundaries of the segment of the layer. A shear deformation can lead to an increase in the crack width. The validity of the numerical simulation results is confirmed by their consistency with the known analytical solution of the same problem.
A new approach to thyristor-based converter commutation configuration for AC-wire DC-motor electric locomotive traction and energy regeneration modes
Authors: Vlasyevskiy S V , Malysheva O A , Melnichenko O V , Barinov I A , Boginskiy S A
Published: September 2020

The widespread use of power converters in modern electric locomotives provides multiple opportunities for railway electric transport, one of them being smooth supply voltage regulation. For electric locomotives with smooth voltage regulation the overall efficiency of energy consumption is dependent on power factor of its power converters, both in traction and regenerative braking modes. Power factor of thyristor-based converters universally used on Russian railways remains to be relatively low. The paper presents a technical proposal to modernize the type AC-wire DC-motor electric locomotive power circuit by introducing a semiconducting discharge shunt in parallel with the subcircuit of rectified current, which allows for a revision of the traditional control algorithm of the converter’s thyristor arms. Mathematical modelling of the proposed circuit suggests a 4.6 % increase in converter power factor in traction mode and an 18.5 % increase in regenerative braking mode under nominal load conditions.
Anderson transition in the cation-substituted compounds ReXMn1-XS
Authors: Kharkov A M , Sitnikov M N , Begisheva O B , Kretinin V V , Abdelbaki Hichem
Published: September 2020

The electrical properties of cation-substituted ReXMn1-XS (Re = Gd, Sm, Ho) compounds are investigated in the temperature range of 77-1200 K. A change in the type of conductivity from semiconductor to “metal” in ReXMn1-XS compounds at a critical concentration of Xc with an increase in the degree of cationic substitution is detected. The metal-dielectric concentration transition in the GdXMn1-XS system is accompanied by a decrease in the value of the specific electrical resistance by 12 orders of magnitude. For Sm0.2Mn0.8S, a sharp maximum of resistance is detected at T = 100 K, which can be caused by scattering of conduction electrons on spin fluctuations of localized electrons. The metal type of conductivity was established for Sm0.25Mn0.75S. In the HoXMn1-XS system, the Anderson transition was detected for XC = 0.3 with a decrease in the value of the specific electrical resistance by 10 orders of magnitude.
Factors influencing flexoelectric polarization in liquid crystals
Authors: Denisova O A
Published: September 2020

The work experimentally investigated the factors affecting the formation and physical parameters of flexoelectric polarization in liquid crystals (LC) with nematic as well as smectic A- and C-phases. Factors such as the heating temperature of the sample, orientation effects near the nematic – isotropic state (N-I) phase transition, and the initial orientation of LC molecules were studied. The thickness of the studied layers is from 10 to 100 μm, the frequency of exposure is 1000 Hz. It was found that the flexosignal takes maximum value in homeotropically oriented samples in the nematic phase. When approaching the N-I phase transition, the magnitude of the flex signal increases, which is associated with an increase in the deviation angle of the director of the LC. As the dipole moment grows, the quadrupole moment also increases. This is due to the tendency of LC molecules to form dipole pairs with antiparallel orientation of electric moments. The estimate of the flexural value U1ω
yielded (for example, for MBBA) with a planar orientation 3 times less than with a homeotropic one. The presence of the second harmonic U2ω
is a consequence of the orientational instability of surface polarization. The rapid growth of U2ω
is associated with an increase in the square of the director deviation angle

θ

¯

d

2

.
Optimization of energy supply schemes using GA
Authors: Bodrenkov E A , Korovkin N V
Published: September 2020

Presented a methodology for determining the optimal configuration of electric circuit by criterion of minimum active power losses in circuit using genetic algorithm. The advantage of the proposed approach is the reduction of number of operations required to calculate the parameters of the electric network mode and as a result increase the speed of search. The theoretical significance lies in the possibility of explicit determination of sensor elements when defining nodal loads by resistances. Practical significance lies in the possibility of applying the approach by electric grid organizations. The algorithm is tested on a model of an electric network with a voltage of 110 kV.
Photonic hook - a new type of self-bending structured light beams
Authors: Baranov P F , Zatonov I A , Bui D B
Published: September 2020

During the last 2 years, it was shown that an electromagnetic beam configuration can be bent after propagation through an asymmetrically shaped (Janus) dielectric particle, which adds a new degree of simplicity for generation of a curved light beam. This effect is termed “photonic hook” (PH) and differs from Airy-family beams. PH features the smallest curvature radius of electromagnetic waves ever reported which is about 2 times smaller than the wavelength of the electromagnetic wave. The nature of a photonic hook is a the dispersion of the phase velocity of the waves inside a trapezoid or composed particle, resulting in an interference afterwards.
Remote radiation monitoring device
Authors: Kulikova V A , Yakovlev V V , Tumanov A Yu , Tumanov V A , Kulinkovich A V
Published: September 2020

This article is devoted to the issue of the necessity of implementation of a remote radiation monitoring device. The main purpose of the article is to present a model of a remote monitoring device. During the research, the author considers the application areas of the device and presents technical requirements and design descriptions of the monitoring. Moreover, the researcher conducts the spectrometric equipment analysis of the device for accurate measurement of the level of radiation pollution. The device model proposed in the article is capable for secure monitoring for personnel and the public in the event of a radiation accident. The author states the importance of such monitoring device, which is primarily designed for automated radiation monitoring of environmental pollution during the operation of ships with nuclear power plants, ships of nuclear-technological services and ships transporting nuclear materials and radioactive substances.
Investigation of the capabilities of convolutional neural networks in object classification problems
Authors: Kozhevnikova T V , Kadura E V , Manzhula I S
Published: September 2020

This paper considers convolutional neural networks to solve the problem of improving the quality of images compressed by the JPEG algorithm. To analyze the qualitative characteristics of networks, the convolutional network L04 is implemented using the Caffe framework. By choosing the optimal optimization algorithm for training the network, its qualitative characteristics have been improved.
Chiral current reversal induced by a quadratic field in the three-leg magnetic lattice
Authors: Sun Tongyue , Zheng Yi , Yang Shi-Jie
Published: September 2020

We study the chiral current of non-interacting bosons in a three-leg lattice subjected to a uniform magnetic flux. The model is equivalent to a spin-1 bosonic lattice with three internal degrees of freedom or a one-dimensional lattice with a three-site synthetic dimension. By manipulating a bias field between the legs which acts as a quadratic Zeeman shift, we can effectively reverse the chiral current on the lattice. The current can also be reversed by increasing the magnetic flux or the inter-leg hopping coefficients, provided that the quadratic field is applied. Three types of current reversal, either related or unrelated to the Meissner-vortex phase transition, are revealed.
A novel system for the comprehensive collection of nonvolatile molecules from human exhaled breath
Authors: Chen Dapeng , Bryden Wayne A , McLoughlin Michael
Published: September 2020

Characterization of nonvolatile molecules in exhaled breath particles can be used for respiratory disease monitoring and diagnosis. Conventional methods for the collection of nonvolatile molecules in breath heavily rely on the physical properties of exhaled breath particles. Strategies taking advantage of their chemical properties have not yet been explored. In the present study, we developed a column system in which the surface chemistry between organic nonvolatile molecules and octadecyl carbon chain was exploited for the comprehensive collection of metabolites, lipids, and proteins. We demonstrated that the collection system had the capture efficiency of 99% and the capacity to capture representative nonvolatile molecules. The collection system was further evaluated using human subjects and proteins collected from human exhaled breath were characterized and identified using gel electrophoresis and bottom-up proteomics. The identified 303 proteins from mass spectrometry were further searched against reported bronchoalveolar lavage fluid proteomes and it was shown that 60 proteins have the tissue origin of lower respiratory airways. In summary, we demonstrate that our collection system can collect nonvolatile molecules from human exhaled breath in an efficient and comprehensive manner and has the potential to be used for the study of respiratory diseases.
Erosion and Sedimentation at Headwater Stream: A Case Study for Pergau Water Intake
Authors: Sulaiman Mohd Sofiyan , Mohd Amin Mohamad Faiz , Yusoff Abdul Hafidz , Samsudin Mohd Fikri , Shukor Aisah Md
Published: September 2020

Headwater stream can be defined as colluvial and fluvial system located at mountainous areas where stream order of less than four is recorded from the source to the outlet point of interest. This river system is crucial not only for impounding activities but high kinetic energy at highland areas able to entrain and transport large amount of sediment particles from upstream to the downstream river reach. Due to strategic location for water intake facilities, a study was carried out to determine the extent of erosion and sedimentation process at Pergau water intakes that conveyed water into Pergau Lake. Three specific aims were formulated: Soil loss determination at catchment scale, sediment load determination at reach scale and river bank stability and toe erosion near the intake facility. A desktop study using remote sensing and GIS tools was executed to determine the extent of soil loss at catchment scale. The sediment load and river bank stability were measured in the field using wading technique. It was concluded that all seven TNB water intake are having low soil loss rate (<10 ton/ha.year) should the current settings of forest land cover is maintained. The recorded sediment load (bed load) only occurred at Suda and Renyok 1 water intake with a rate of 0.0024 kg/s and 0.03 kg/s, respectively. High eroded material at toe was simulated at Renyok 1 and Suda Intake. The high sediment load at Renyok 1 is a manifest from unstable toe material near the water intake. Therefore, a close monitoring should be attained at the upstream from Renyok 1 intake to assess any land use change or disturbance activities.
Effect of Monsoonal Period toward Night-time Ground Level Ozone in East Coast Malaysia
Authors: Mohamad Nazir Amni Umirah , Awang Norrimi Rosaida , Ramli Nor Azam , Daliman Shaparas , Aziz Hasifah Abdul
Published: September 2020

This study aims to identify the effect of monsoonal period toward nighttime ground level ozone in East Coast Malaysia depending on different land use area which is industrial and urban areas. The concentration of O3, NO, NO2 temperature (T), relative humidity (RH) and wind speed (WS) were used and collected from Air Quality Division of the Department of Environment, Malaysia. The data proceeded in descriptive analysis and statistical analysis. Temperature, relative humidity and wind speed parameters (symbol of East Coast Monsoonal period), was compared with O3, NO and NO2 concentration with Pearson correlation analysis. During nighttime, O3 concentration continuously decreasing starting at 7 p.m. promotes by chemical removal and other removal processes. The highest nighttime O3 concentration was recorded 65 ppb (Kemaman) with the lower nighttime ozone achieved zero value. Meanwhile, nighttime O3 concentration in Kota Baharu (nighttime) was recorded lower with maximum (612 ppb) and mean (9.15±8.60 ppb) compared to Kemaman. The temperature and relative humidity correlation with O3 concentration in both locations shown different correlation as Kemaman - 0.149 and 0.212 while Kota Baharu exhibited 0.137 and -0.159. Meanwhile, wind speed has a positive correlation in both locations as Kemaman is 0.388 and Kota Baharu is 0.462 which indicates wind was a factor that induces ozone formation as ozone was transported to the monitoring area. Therefore, NO, NO2, T, RH and WS was not the only factor influences ozone depletion during nighttime as the correlation display was lower.
A GIS-Based Flood Vulnerability Assessment in Pasir Mas, Kelantan
Authors: Mohamd Hanan Nur Aniza , Abas Muhamad Azahar , Md Nor Amal Najihah , Mohd Amin Mohamad Faiz , Hassin Nor Hizami , Yusoff Abdul Hafidz , Awang Norrimi Rosaida , Mohamed Sulzakimin , Wee Seow Ta
Published: September 2020

The flood events are now intense because of localized physical and climatic factors, resulting in risks to the environment and the population. Besides, the difficult to identify the flood vulnerable area at Pasir Mas, Kelantan had become the main problem because lack of comprehensive information which as a medium to communicating the flood risk, new unplanned developments and insufficient drainage systems. Hence, the development of a vulnerability map for flood risk of flooding management still lacks, which made the situation more considerable. Vulnerability is the primary construct in flood risk management. Therefore, this study aims to identify the variables which contribute to the risk of flooding based on the characteristics of the area and develop a flood vulnerability map using Geographical Information Systems (GIS) and Remote Sensing. In this study, the land use data, amount average of rainfall data and digital elevation model (DEM) data were used to produce a vulnerable flood map for the study area. The hydrology and weight overlay (spatial analyst) techniques were used to determine the flood vulnerable area on physical and climatic factors that cause flooding in Pasir Mas and to develop the vulnerable flood map in Pasir Mas. The vulnerability area had been determined based on the scale 1 (no vulnerability), 2 (low vulnerability), 3 (reasonable vulnerability), 4 (moderate vulnerability) and 5 (high vulnerability). The findings show that the area located at the water bodies recorded the most highly vulnerable compared to another area because water bodies store the water. When surface water run-off from the surrounding area exceeds the level of water bodies, it increases the flow capacity of the water and causes the flood. From here, it makes the water bodies and area surrounded it more vulnerable. It is expected within this vulnerable flood map will able to assist the responsible parties to communicate and give an option to those affected people to ensure the effectiveness of the emergency response assistance and aid to victims for better preparedness capability.
Impact of land use changes on forest catchment area in Pergau Lake, Kelantan
Authors: Muhamad Nor Amal Najihah , Bahri Ayuni Samsul , Nor Shukor Md. , Yusoff Abdul Hafidz , Abas Muhamad Azahar , Jamil Rohazaini Muhammad , Aziz Hasifah Abdul , Nawawi Aisyah , Ibrahim Norfadhilah , Mohd Amin Mohamad Faiz
Published: September 2020

The Pergau lake basin is a man-made water catchment area comprise of 460 hectares due to the construction of hydroelectric dams in Pergau. It is located about 125 km southwest of Kota Bharu in the Jeli district in Kelantan and managed by Tenaga Nasional Berhad. The lake is rich in natural resources and the forest in the basin acts as a reservoir through water absorption and storage. Forests within the area catchments and basins can control soil erosion and erosion of river banks as well slope collapse is one of the sources of risk floods in terms of damage to property and infrastructure such as bridges and road. However, rapid population growth and urbanisation induced the pressure from human activities have been expanded into the forest catchment area. Therefore this study was conducted in the Pergau Lake (Dam) to safeguard their importance for socio-economic, well-being, ecotourism potential and sustaining its biodiversity. This study aims to predict the land use changes in the study area for 2035, parameterised with satellite images in 1988, 2003 and 2018 and the physical parameter such as slope, road, elevation, distance from built up area, green space edge and waterbody. The integrated approach of remote sensing, Geographical Information System (GIS) and Land Change Modeler-Markov Change Model were used to analyze the changes and their spatial pattern. The results showed that between 1994 and 2004, and between 2004 and 2014 the forest landscape in the Pergau Lake were decreased due to the development of the built-up area. Thus, the results will hopefully take into consideration for land use planning and forest protection for sustainable management planning of the forest catchment area. It is indicated that the spatial effect of green space is influenced by the historical spatial changes, implementation of the previous master planning efforts and uncontrolled land use expansion. This study is designed to provide the novel integrated approach for predicting landscape changes for the forest catchment area to provide the initial guideline for sustainable planning and management of forest catchment area.