bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Ultrafine Fe-W-Al-Ti-Ni-C-B Powders by Mechanical Alloying
Authors: Chikhradze Mikheil , Abashidze Guram , Chikhradze Nikoloz , Tsverava David , Stecuła Kinga
Published: November 2019

The goal of the presented research was syntheses of the ultrafine and nanopowder blends by Mechanical Alloying from Fe-W-Al-Ti-Ni-B-C compositions for further application as a precursor for fabrication bulk High-Entropy Alloy (HEA) by explosive compaction technology. The presented paper describes the preliminary investigations of mechanical alloying of Fe-W-Al-Ti-Ni-B-C powders. Laboratory vibrating sieve equipment was used for sorting the initial powders for the reduction of particle size. For the experiments were used powders of Fe-W-Al-Ti-Ni-B-C system consisting of five major metallic and two minor non-metallic B and C elements were used for mechanical alloying. The crystalline coarse Aluminum, Titanium, Carbon and Nickel, fine-grained iron and tungsten and amorphous Boron powders were used as initial components. The Fe, W, Al, Ti and Ni powders were preliminary checked by “Explorer 5000 XRF” by Skyray instrument and verified. Based on the literature review, theoretical investigation and phase diagrams for mechanical alloying were selected two compositions with the following molar ratio: Fe20W15Al15Ti20Ni20B5C5; Fe25W25Al10Ti15Ni15B5C5; The mechanical alloying was realized on the high energy ball mill with zirconium oxide jars and balls. The ball to powder mass ratio was 10:1, the rotation speed was 500rpm. The process was carried out in dry conditions. The time of mechanical alloying was 5h, 10h and 14 h. The powders were prepared for preliminary analyses and assessment of particle size. The SEM and optical microscopy results of mechanical alloying are presented in the paper.
Analysis of the Consequences of Methane Combustion in a Mined Dog Heading
Authors: Tutak Magdalena , Brodny Jarosław
Published: November 2019

One of the most common and, at the same time, the most serious threats in underground hard coal mining, which often requires long rescue operations, is the methane hazard. It is related to the potential ignition and/or explosion of methane in mixture with air. The hazard grows along with the increasing depth of mining works and the concentration of production in mine headings. Methane, as an organic gas, is released to the mining atmosphere in the exposed body of coal. Accumulation of explosive concentrations of methane in a mine heading, as well as adequate oxygen concentration levels and the presence of a trigger (e.g. in the form of a spark) may lead to methane explosion or combustion. Methane ignition and combustion leads to a series of chemical reactions, which cause the emission of harmful and poisonous gases of high temperature into the mining atmosphere (the temperature of methane combustion in mixture with air is approx. 1,875°C, with methane content of approx. 10%). These gases are formed during methane combustion. Countering the methane hazard primarily involves elimination of the potential for dangerous methane concentration levels and application of suitable protective measures to prevent methane ignition. However, despite the preventive measures in use, there were 34 incidents related to the methane hazard in Polish hard coal mines in the years 2008–2018, including 10 cases of methane ignition in the mined dog headings. Therefore, it is necessary to carry out research in order to predict the consequences caused by methane combustion in mine headings. Taking into consideration the remarks above, it was assumed that the numerical analysis of methane combustion in the mined dog heading and of the impact of this combustion on the parameters of the air stream flowing through this heading would be conducted using the CFD method. The objective of the analysis was to determine the effects of methane combustion on the composition of the mining atmosphere and the physical parameters of the gas mixture generated in this process. The paper presents the distributions for the physical parameters of the resulting gas mixture and the concentration of fire gases. Moreover, it demonstrates the distributions for temperature and oxygen concentration levels in the heading under analysis.
Geostatistical Modeling by the Ordinary Kriging in the Estimation of Mineral Resources on the Kieselguhr Mine, Algeria
Authors: Lamamra Abdessattar , Neguritsa Dimitriy L , Mazari Messaoud
Published: November 2019

The most important step in a feasibility study of a mining project is the determination of reserves in situ. But the question which arises that no method of estimation can give exact value since there is inevitably an associated error when it is important to know the order of magnitude. Decision-makers need to know if the estimated content is correct or not. Geostatistics can help the mining engineer to obtain from the available information, and thus, enable him to decide if the project deserves more investments. Geostatistics provides not only the estimated value but also with the kriging variance, a measure of the accuracy of the estimate. This is one of the superiorities of geostatistics over traditional methods of estimating reserves. In this article, the Kieselguhr deposit reserve of the Sig mine (western Algeria) was evaluated according to the linear geostatistical method with ordinary Kriging (OK), to know the economic value of this mine that allows the exploitation of this deposit, and to carry out study cartography accompanied by 2D modeling of deposit. Finally, we obtained maps in which we could estimate exploitable and geological reserves, and know the characteristics of the deposit.
Refraction Correction of the Acoustic Wave in Multibeam Systems
Authors: Makar Artur
Published: November 2019

Dynamic surveys of the sea bottom that rely on determination of reflection points of the acoustic wave transmitted by the echosounder use the wave field theory for determination of the trajectories of the acoustic ray. Complex multibeam echosounder systems that use diagonal beams to determine the coordinates of reflecting points on the sea bed, must take into consideration the refraction phenomenon. Beam inflexion depends on the variability of sound’s velocity in water. It is increasingly more important for beams most inflected from the plumb line. It is a determinant of the angle zone of echosounder’s beam and swath width. The efficiency of bathymetric surveys relies on the swath width. It is 3-5 times the water depth for a multibeam echosounder and up to 12 times water depth for an interferometric one. High value of swath width achieved for high beams inflexion decreases the reliability of the Digital Sea Bottom Model built by data recorded during the bathymetric surveys. This article presents results of correction of the phenomenon of non-linear propagation of the acoustic wave in the multibeam echosounder calibration process in the area where the depth does not exceed 30m. A calibration test was utilised on the perpendicular profiles to determine the variance of depths. Depths measured by the diagonal beams were verified using a vertical beam during surveys on perpendicular profile. Popular models for determining the trajectory of an acoustic wave were used – one based on Snell’s law and another, a new one developed by TU Delft. The geospatial data was sourced using R2Sonic multibeam echosounder during the preliminary stage of bathymetric sounding.
Macroseismic Intensity Estimation from Instrumental Ground Motion Recordings in the Case of Small and Moderate Vrancea Subcrustal Earthquakes
Authors: Adelina Moldovan Iren , Petruta Constantin Angela , Luminita Ardeleanu , Constantin Ionescu , Bogdan Grecu , Marius Manea Liviu , Dragos Toma Danila , Victorin-Emilian Toader , Raluca Partheniu , Florinela Manea Elena , Alexandru Tiganescu , Otilia Placinta Anica
Published: November 2019

Romania is one of the most seismic-prone countries in Europe due to the periodically occurrence of strong intermediate-depth earthquakes in Vrancea seismogenic zone. The Vrancea area is located beneath the South-Eastern Carpathian Arc bend, at the contact between the East - European plate and the Intra-Alpine and Moesian sub-plates. An intense seismic activity is recorded in the mantle, within a narrow, almost vertical descending volume between 60 and 180 km depth. Earthquakes with magnitudes larger than 5.0 (Mw) and macroseismic effects exceeding V MSK degrees on extended populated area occur in Vrancea seismic zone, with a return period of around 2 years. Besides the extended scientific studies, the near real time estimation of the macroseismic intensity recently became mandatory for the insurance companies to cover some of the losses and damages that earthquakes might cause to houses, belongings, and other buildings. The first approach to obtain intensity values was to develop an online environment for collecting people feedback regarding the effects of earthquakes and for the automatic approximation of the intensity. The automatic intensity estimation code from the online feedback proposed by [1], [2] and adopted by [3] for the Romanian earthquakes was improved and used for this study. Additionally, there were used prediction equations to obtain intensity values from the epicentral intensity, and epicentral and hypocentral distances. Besides the estimation of macroseismic intensities from online people feedback and from attenuation relations, equations for conversion of peak ground acceleration in macroseismic intensity were also required for a rapid evaluation of ground motion effects. In order to avoid the increase of the prediction uncertainties, the data must be selected in such a way that they represent the parameters’ rank for which the prediction will be accomplished and the selected data must be representative for the investigated regions and seismic source. In this paper were developed conversion methods from PGA to macroseismic intensity for moderate intermediate depths earthquakes with 4.5<Mw<6.0. All the studies were realised in the case of Vrancea recent (2014-2019) moderate intermediate depth earthquakes, felt on the extra-Carpathian region.
Mapping of Induced Effects of an Earthquake in the Region of Algiers, Algeria Using the Geographical Information System GIS
Authors: Sadou O. , Bourenane H. , Louni C. , Balla N. , Haddouche A.
Published: November 2019

Landslides, rock blocks falls, liquefaction, the appearance of the surface fault and flood present the principle geological-hazard in relationship with earthquakes which will be mapped in the region of Algiers. The determination of these areas passes through a qualitative and quantitative analysis based on a recognition of the soil conditions; geological, lithological, hydro-geological, topographic, morphological and geotechnical. The assessment and mapping of the degree of induced hazard allows individualizing homogeneous areas that can behave similarly during the earthquakes.
Risk charter for medieval defensive earthen architecture in southern Spain
Authors: Manrique Jesus Garrido , Gutierrez-Carrillo Maria Lourdes , Melgarejo Emilio Molero
Published: November 2019

Medieval defensive earthen architecture is typically represented by big and well maintained defensive walls, lookout towers or castles despite mostly represented by remains of tower walls or defensive walls. While studies on natural hazards have been carried out concerning these castles or lookout towers, there are no studies on defensive walls. Both are certainly significant from a cultural heritage perspective, despite the fact that the latter are less popular for the general public. In Southeast Spain, most of this kind of architecture has been affected, and occasionally reconstructed, by destructive earthquakes and/or landslides, in accordance with historical chronicles or field evidence, however, there are no records of low-scale natural hazards. Hence, aware of the importance of the prevention of natural hazards regarding the conservation of the cultural heritage, a National Emergency and Risk Management Plan for the Cultural Heritage, a National Plan for Preventive Conservation as well as a National Plan for Defensive Architecture have been enacted by the Spanish Ministry of Education, Culture and Sport. According to these plans, a risk charter, including natural and man-made hazards, should be completed in order to improve investment programming. Cultural heritage risk and cultural assets maps should be connected in order to become an instrument for managing preventive conservation. Natural hazards studies should be conducted in order to protect cultural heritage, though they are not usually performed, most likely due to their cost. However, some natural hazards studies have been published in scientific journals, mainly signed by university researchers or various Spanish research institutions such as the Geological and Mining Institute of Spain. Some of them, including the Spanish Seismic Network or the old Ministry of Environment (currently known as the Ministry for Ecological Transition), have published several hazard and risk maps which can be usually used in GIS format. Yet, most of them are not even known by researchers on cultural heritage due to the different administrative levels in charge of natural hazards. In this paper, some recommendations to prevent natural hazards in medieval defensive earthen architecture will be discussed.
Proximate and Ultimate Analysis Before and After Physical & Chemical Demineralization
Authors: Bilen Mehmet
Published: November 2019

In this study, a total of 12 coal samples were collected. Physical and chemical cleaning were employed on these collected coal samples. In order to understand the effect of physical & chemical cleaning on these samples, samples characterization were performed in terms of proximate and ultimate analysis. Calorific values of each corresponding clean coal samples were also determined. After chemical cleaning calorific values of each sample decreased, while chemical cleaning resulted in ultra clean coals as regards to ash content (average of 0.5 % ash content). Volatile matter content each corresponding sample after chemical cleaning have higher percentage with respect to the ones after physical cleaning. However for some specific sample, the increase in volatile matter content after chemical cleaning is more than 200 %. Fixed carbon percentages do not show tremendous changes as regards to chemical cleaning, however they decrease for some and increase for some other after chemical cleaning. Calorific values decreases for the all samples after chemical cleaning. Ultimate analysis (C, H, N and O) was also determined after physical and chemical cleaning. Sulphur decreased for all samples after chemical cleaning as expected. Taking these variations into consideration, calorific value decrease were deducted and possible reasons of this decrease was inferred. Corresponding differentiations were compared to calorific value differentiation and the most significant reasoning of the calorific value decrease was evaluated.
Logarithmic expression of Globigerina bulloides shell evolution through the biometric analysis: Paleoceanographic implications for the late Quaternary
Authors: Zarkogiannis Stergios , Kontakiotis George , Antonarakou Assimina
Published: November 2019

Fossil foraminifera are a treasure trove of information in applications ranging from microevolution to paleoclimatology. The architecture of their tests is of the key importance in systematic and phylogenetic studies and can reveal micro-evolutionary traits through the biometric analyses. In the present paper, we analyze the laws of growth that control planktonic foraminifera shell morphology. We report the results of a biometric study of the temporal variation in the shell shape and chamber size of the cosmopolitan, subpolar to temperate species Globigerina bulloides d’Orbigny from core top sediments in the eastern tropical Atlantic Ocean. Morphological variation in terms of test shape and adult chamber size in G. bulloides, has been measured in 116 down core sediment samples from the tropical waters (19°N) of the northern Antarctic Ocean and has resulted in a model that simulates the basic morphology (chamber size and spatial arrangement) of planktonic foraminiferal shells of that species. The investigated samples comprise a continuous record that spans the last 200 kyrs. The specimens for this morphometric study were picked from a restricted sieve fraction and were mounted for Scanning Electron Microscopy (SEM) analysis. The restricted size of the specimens constrained the analysis to adult specimens and minimized ontogenic effects while allowing the documentation of very small overall changes in the parameters under investigation in time. The dimensions that were measured for each test were its height, width and the diameters of the last seven chambers. This allowed the determination of chamber centers and their analogies resulting in a mathematical model based on a logarithmic spiral equation that describes the evolution of the test with the growth during their adult phases. The model presented herein belongs to a family of so-called “fixed-axis” coiling models.
Modelling of Work of Cut and Stretchy Sheet in Span Beam Structures with the Mixed Reinforcement
Authors: Burchenya Sofiya , Famulyak Yuriy , Sobczak-Piastka Justyna
Published: November 2019

The constant growth of the intensity and volumes of automobile transportation causes the necessity of the increasing the requirements to the serviceability of transport facilities. The issue of the serviceability and safe operation of the existing highway or pedestrian bridges, which were built many years ago, is always relevant. Therefore, there is a choice: either to restore and strengthen the existing facilities or to replace them completely. It is expedient and efficient to use a steel cut and stretchy sheet in the form of the external ribbon reinforcement at the strengthening of the reinforced concrete span bridge structures. In the future, the steel cut and stretchy sheet is properly attached to the surface of the structure and the filling of the sheet cell is done by the layer of the cement and sandy solution (the process of concrete spraying) or protected by a concrete layer for the prevention of the sheet corrosion. Such a cut and stretchy sheet can be effectively used in new structural elements at new construction as a working longitudinal or transversal reinforcement. An effective version of the use of the cut and stretchy sheet is possible for the strengthening not only bending structures but also compressed and compressed out of center reinforced concrete and stone ones. Thus, the issue of the research and modeling of the work of the steel cut and stretchy sheet in the array of concrete under the linear stressed state conditions is of vital importance. The article presents the results of the experimental and theoretical research of the work of the steel cut and stretchy sheet under load; provided the physical model of such a process; substantiates the effectiveness of its use and the placement in span beam bridge structures.
Influence of Freeze-Thaw Temperature on Load-Bearing Capacity of Steel-Concrete Beams Carrying Transverse Loads
Authors: Famulyak Yuriy , Hrytsevych Andriy , Sobczak-Piastka Justyna
Published: November 2019

The use of steel-concrete structures in which, external or extra-strong non-stressed sheet reinforcement are widely used in the stretched (sometimes in the compressed zone) in industrial construction as well as in the process of bridges and tunnels construction. Such structures are continuously thermal loaded during operation. Existing calculation methods of steel-concrete structures do not allow accurate estimation of the influence of freeze-thaw temperatures because there are contradictions considering this problem. The method of frost resistance calculating in Ukraine researches concrete cubes but it does not take into account the existence of reinforcement in the construction, its quantity and placement in the cross-section. This problem became even more relevant under conditions of Ukraine transition to the European design standards. According to the demand of the Eurocode the number of cross reinforcement in the back-up area is increased in comparison with national design standards. Single-span steel-concrete beams were manufactured and examined in order to determine the influence of freeze-thaw temperature on the constructions. Flat deformed reinforcement was adopted for the perception of tensile forces. To determine the strength characteristics of concrete, cubes and prisms were additionally made from the same concrete as the beams. To determine the freezing point of the beam and measure its internal temperature, 10 thermocouples were introduced into the beam’s body. On the basis of the adopted research method a graph of the freezing rate of the experimental beams and the destructive influence of freeze-thaw temperature on the load-bearing capacity of the steel-concrete beams were obtained.
Hydraulic Computer Analysis of a River Sector Under Altered Flowing Regime Due to an Existing Bridge and Suggested Specific Correction Works
Authors: Popescu-Busan Ioana - Alina , Lazar Gheorghe I. , Constantin Albert Titus , Nicoara Serban-Vlad
Published: November 2019

The paper presents a 2D numerical modelling of the water flow transit under an altered regime on Strei River, specifically for a 633m stretch influenced by a driveway crossing concrete structure of four gaps (about 71m total span) on a national road outside of Deva Town, Romania. The analysis considers a possible (and requested by specialised regulations) accidental highwaters flow development as assimilated from a specific hydrologic phenomenon that occurred on site during the special spring season of 2000. Taking into consideration the findings and general flow improvement suggestions of a technical expertise ordered by the rivers national administration, the present developed hydraulic model follows the technical recommendations of a formerly feasibility study with respect to streambed correction in the range of the mentioned bridge, specifically the downstream accomplishment of a bottom step (for scourings re-siltation) and two left side river groins (to direct the stream flow towards the central span of a following railway bridge, not covered by present model), accompanied by banks protection and alluvia deposits removing works. Under the given flow and geometry conditions, the study accomplished by the help of HEC-RAS 5.0.6 specialized software package looks to estimate the water surface level and velocity development in space and time, and so to draw the future state of flow transition along the analysed sector. As about the simulation output, the most important conclusions are that the riverbed would be able to discharge the significant flow of 0.1% overrunning probability at a maximum surface level below the structure safety values. In the same time, the reached velocity and particle tracking visualizations suggest a more stable and efficient riverbed time behaviour.
Numerical study of the water discharge on a fish stepped passage at a low head dam
Authors: Bratanovici Cristian , Popescu-Busan Ioana - Alina , Lazar Gheorghe , Constantin Albert Titus , Nicoara Serban-Vlad
Published: November 2019

Whereby the water course is considered a continuous system with hydrological connectivity – longitudinal, lateral, vertical – and variable in time, the design and implementation of barraging steps on water courses will have to follow the river dynamics and to respect the ecological concepts. Looking to diminish the negative impact on the environment, the promoted technical solution needs to consider a series of principles and criteria specific to the river basin for the conservation of nature and biodiversity. A specific river development assuming the accomplishment of a low head overflowing step ending with a water energy dissipater will have to be additionally endowed, according to nowadays legislation, with a corresponding fishway structure preserving the natural passing. The paper presents a numerical simulation of the water discharge transported by the fish stepped passage associated to the low head overflowing Livezeni Dam on Jiu River in Hunedoara County, Romania, considering the possible accidental high waters phenomenon given as a synthetic levels’ hydrograph. The hydraulic model looks to analyse the maximum discharges for the special structure and also to estimate the maximum values for water velocity in the strangled cross sections. As a consequent, the adjustment of the steps geometry or number can be studied in order to fulfil the nowadays regulation on the subject.
Analyzes of brown coal in connection with higher sulfur contents in Sokolovská uhelná
Authors: Duraj Milos , Augustin Marek , Niemiec Dominik , Yang Shuran , Kubac Jan , Matuszkova Barbara , Sombathy Erik , Montero Orlando Arencibia , Yilmaz Isik , Marschalko Marian
Published: November 2019

The field of energy raw materials, including caustobioliths, still plays a priority role in the raw materials policy of many states. One of the important areas in which these reserves are currently mined is the Sokolov Basin in the Czech Republic. The current question on this deposit is the increased sulfur content in some locations of the Antonín seam.
Investigation of Properties of Mortars Containing Waste Stone Powder Instead of Sand Under Freezing-Thawing Effect
Authors: Aral İbrahim Feda , Cihan Mehmet Timur
Published: November 2019

Nowadays, sustainable production is vitally important in consideration of limited raw materials and an environmental welfare. Sustainable production encourages the use of several industrial wastes as raw materials in different fields. Water and aggregate are among the most consumed items on the earth. Waste powders, with a size of 75 μm or less, formed during the aggregate production process affect both the environment and human health negatively. For sustainable aggregate production, it is important that the waste powder generated during the aggregate production phase is used in the concrete industry. Limestone, basalt and dolomite are commonly used as concrete aggregate. In this study, limestone, basalt and dolomite waste powders were replaced with fine aggregate (sand). Reference samples (0 %) and 20%-30% waste stone powder produced by replacing standard sand with mortar. The freeze-thaw effect (40 cycles) on compressive strength, flexural strength, ultrasonic pulse velocity, weight loss are analysed. For this purpose, a total of 105 (21×5) 40×40×160 mm prism samples were produced. Under the influence of freeze-thaw cycles, the loss of weight in samples produced by replacement of standard sand and waste stone powders is less than that of the reference samples. The ultrasonic pulse velocity tend to increase in general as the number of freeze-thaw cycles increases. The flexural strength rises as the replacement rate is increased, and after the freeze-thaw cycle, a slight decline is observed. The compressive strength values decrease as the replacement rate is increased. It decreases at the end of the 10th freeze-thaw cycle but the variability tend decrease at extending cycles (20-40).
Leachate Treatment Plants Used Inside Compliant Landfills, Solutions to Comply with Technical Environmental Protection Standards
Authors: Ioana-Alina Cretan
Published: November 2019

The purpose of this paper is to present solutions chosen for the treatment of leachate resulting from the storage of non-hazardous solid wastes, from a landfill site. The technical characteristics of the installations dealing with the leachate of the compliant landfills must be designed so that the characteristics of the effluent correspond to the limits of pollutant loading of industrial and urban waste water into the discharge into the treatment plants or natural receptacles. From a technical point of view, water management solutions at the complaint landfill site provide a distinct separation of the rainwater from the site and the compliant landfill leachate resulting from wastes moisture content and rainwater that percolates the waste cell in operation. The sewage treatment plants aim to treat the leachate from the body of the landfill and do not interfere in the water balance in the related service area inside the landfill location.
Editorial Preface
Authors: Vatin Nikolai I. , Galishnikova Vera V. , Pahl Peter J. , Kharun Makhmud
Published: November 2019

The International Scientific and Practical Conference Engineering Systems (ISPCES) held annually at the Peoples’ Friendship University of Russia (RUDN University), has created a platform for summarizing research in various areas of engineering. The aim of the conference is to foster and conduct collaborative interdisciplinary research amongst the researchers, professionals and industrialists to share their research experiences and indulge in interactive discussions and special sessions at the event.

The present proceedings include a selection of papers submitted to the International Scientific and Practical Conference Engineering Systems - 2019 (ISPCES 2019), which took place during 4-5 April 2019 in the RUDN University, Moscow, Russia. The conference proceedings present recent advances in the field of fundamental science, engineering research and materials science. We hope that this collection will be useful for many specialists and researchers from the mentioned areas.

We would like to thank everyone who was part of this conference and look forward to seeing everyone again next year at ISPCES 2020 dedicated to the 60th anniversary of RUDN University.
Radon risk reduction to population
Authors: Vysotskii S P , Levchenko L G
Published: November 2019

Ranking the risks of deaths from various factors affecting the human body shows the leading effect of radon. The main source of radon entry into the dwelling is the soil under the building. Health risks analysis was performed at various levels of radon concentrations. Based on analyses of radon exposure data made in the USA, analytical dependencies of health risks are derived depending on the radon concentration. Analysed the path of penetration of radon in the home. The cost of the work to protect the home from radon penetration has been estimated. Analysis of the appearance of oncological diseases of the respiratory organs for residents of the region according to statistical data depends on the number of floors. The approach to the choice of the level of protection from radon exposure according to the ALARA principle – to ensure the most reasonable achievable level of radon concentration is substantiated. The analysis of the protective properties of various building materials is performed.
Analysis of the theory of calculation of fiber-reinforced concrete with non-steel fibers
Authors: Markovich A S , Koroteev D D , Abu Mahadi M I , Miloserdova D A
Published: November 2019

The fiber-reinforced concrete finds more applications in modern construction. This material has improved strength and deformation characteristics. The fiber-reinforced concrete is considered to be one of the most promising building materials in the world practice. The experience of using this material in developed countries, such as the USA, UK, Japan, Germany, Italy, France, Australia, has shown the good technical and economic indicators in building constructions. Recently, the base of standards for preparation, calculation and design of such concretes has been prepared and introduced in Russia. The method of determination of the class of the fiber-reinforced concrete by residual tensile strength, the calculation of the strength of standard sections, the diagrams of the deformation is discussed in the article based on the new Code of Practice. The obtained results of analysis of the theory of calculation suggest further studies of the properties and physical characteristics.
Methodology for calculating the stress-strain state of robotic system made of composite materials
Authors: Khayrnasov K Z
Published: November 2019

The methodology for calculating the stress-strain state of robotic systems made of composite material under dynamic load is considered. The problem is solved by the finite element method. Formulas for determining the reduced stiffness of a multilayer composite material are given depending on the location of the base of the composite in layers, as well as in three-layer structures consisting of external bearing layers and a layer of aggregate between them. The method of placing the base layers of a composite material in the structure under study along the lines of maximum stress is considered. Particular attention is paid to the accounting of gearboxes, gears and support bearings in robotic systems. The results obtained in relation to the multi-stage dynamic stand, made of composite material.
Comparison of n-LSB embedding approach in different color spaces
Authors: Cataltas Ozcan , Tutuncu Kemal
Published: November 2019

Today, secure communication is one of the biggest goals that people want to achieve. There are many different methods to ensure security in data communication. Steganography is one of the methods that can be used in secure data communication. In this study, n-LSB embedding method based on reducing the amount of distortion generated by the classical Least Significant Bit substitution method that we introduced in another study has been applied in both RGB color space and HSI, XYZ and YCbCr color spaces. In the embedding process, 3 message bits were embedded in each color channel. 7.94 kb data is embedded on 3 different cover images. The obtained results were compared with the PSNR criterion, which is the criterion of image quality evaluation, and it is seen that proposed n-LSB approach gives better results in HSI color space for 3 cover images. The highest PSNR value obtained was 83.907 dB.
Tree-seed algorithm in solving real-life optimization problems
Authors: Sahman M A , Cinar A C , Saritas I , Yasar A
Published: November 2019

Tree-seed algorithm (TSA) is a nature-inspired and population-based algorithm for solving continuous optimization problems. The tree-seed relationship is the main motivation of this algorithm. TSA has only two peculiar parameters which are the total number of trees in the stand (pop) and the controller of the seed production (search tendency). Although many problems have been solved in the literature by TSA which is the successful optimizer for low dimensional unconstrained continuous problems, real-life problems have not been addressed yet. In this study, six continuous unconstrained real-life optimization problems (gas transmission compressor design, optimal capacity of gas production facility, gear train design, frequency modulation sounds parameter identification, the spread spectrum radar polyphase code design with 10 decision variables, the spread spectrum radar polyphase code design with 20 decision variables) have been solved. It is seen that choosing the number of the population as 50 and the value of search tendency as 0.1 is appropriate according to experimental results for these problems.
Comparison of typical access networks with AMOOFDM based access networks
Authors: Yazbeck H A , Belyaev V V
Published: November 2019

Access networks are under constant development looking for customer’s satisfaction by enhancing the internet service speed and the cost of the service. Moreover, trying to serve as many residential units as possible by extending the distance reach of the access network to cover a part of a big city or to reach a rural area in a range up to 60 km. Nowaday’s networks still experience limitations in services, coverage area, and still pricey for average customers. However, a significant percentage of these networks still using the terrestrial radio wave telecommunications to distribute the service inside or between city blocks, while others use the fiber to the home (FTTH). In this article, we are comparing the performance of the currently operated access networks to the adaptively modulated optical orthogonal frequency multiplexing (AMOOFDM) based access networks, according to the bit-rate, and the distance reach of these networks; highlighting the advantages of the AMOOFDM system using some types of the semiconductor optical amplifier (SOA) as an intensity modulator.
Composite materials for Hi-Tech printed circuit boards
Authors: Medvedev A M
Published: November 2019

The development of printed circuit board technology is subject to the general trend of electronics development - an increase in functionality and performance. This requires printed circuit boards to increase the assembly density of electronic components and interconnections and reduction of constructive delays in transmission lines of information. In turn, this requires the use of base materials with good dimensional stability and reduced values of dielectric permittivity and dielectric losses. Operability of gigabit electronics largely depends on the state of the surface of the printed conductors, since at high frequencies it is affected by the skin effect. Producers of basic materials, trying to meet these requirements, remain in the field of composite materials, so as not to change the structure of the existing production, based on the use of basic technologies of printed circuit boards. This article is based on the presentation of the properties of new materials from the catalogs of the companies Panasonic, Hitachi (Japan) and Isola (Germany).
Effect of fixing the pass-through turning tool in the tool holder on the roughness and surface macro deviations during turning
Authors: Allenov D , Deinova K , Konoplev V , Korzin A
Published: November 2019

A study of the effect of the tool overhang length from the tool holder and cutting forces corresponding to different sizes of the removed layer on the formation of the quality of the surface layer of parts during turning is presented. Linear displacements arising in a stress-strain state and roughness parameters were used as estimated parameters. It is revealed that the quality of the surface layer improves with a decrease in vibration in the zone of contact between the workpiece and the tool.
Relationship between hardness and optical properties of diamond-like carbon coatings
Authors: Suasnavas C V , Makeev M O , Osipkov A S , Solano N B , Shupenev A E , Mikhalev P A
Published: November 2019

Correlation between hardness and optical properties of diamond-like carbon (DLC) coatings is considered. Various methods for the characterization of mechanical, chemical and optical properties of DLC coatings are used; however, some of these methods are destructive, and others are non-destructive. It was found that optical properties of DLC coatings are proportional to their hardness. The mathematical expression that allows to calculate the hardness of a DLC coating according to its refractive index is proposed. Therefore, it is possible to avoid the use of destructive methods (such as nano-indentation technique) to characterize DLC coatings.
Nonlinear deformation of a solid body on the basis of flow theory and realization of FEM in mixed formulation
Authors: Gureeva N A , Kiseleva R Z , Nikolaev A P
Published: November 2019

In the mixed formulation, an algorithm for the formation of a hexahedral finite element deformation matrix at the loading step to determine the stress-strain state of a solid body beyond the elastic limit based on the theory of plastic flow is developed in a curvilinear coordinate system. Stresses and displacements are taken as nodal unknowns. The approximation of the required values of the inner point of the finite element through the nodal unknowns was carried out by trilinear functions. To obtain the deformation matrix of the hexahedral finite element, a mixed functional on the equality of the real and possible works of external and internal forces with the replacement of the actual work of internal forces by the difference of the total and additional work of internal forces at the loading step is used.
Application of a triangular finite element with Lagrange correction factors in calculations of thin shells of ellipsoidal type
Authors: Klochkov Yu V , Nikolaev A P , Vakhnina O V , Sobolevskaya T A , Yu Klochkov M
Published: November 2019

The study of the stress-strain state of a thin shell of an ellipsoidal type was carried out. The finite element method was used as a research tool using the triangular fragment of the middle surface as the discretization element. The nodal variable parameters of the triangular element of discretization selected the components of the displacement vector, their first and second derivatives with respect to global curvilinear coordinates. Fifth-degree polynomials were used as polynomial functions. To improve the consistency of the triangular element of discretization on the boundaries of adjacent elements, the Lagrange correction factors in the nodes entered in the midpoints of the sides of the triangular element were additionally used as unknowns. The analysis of the results of the calculation of the thin shell of the ellipsoidal type showed high efficiency of using the modified triangular finite element.
The Riemann problem for a weakly hyperbolic two-phase flow model of a dispersed phase in a carrier fluid
Authors: Hantke Maren , Matern Christoph , Ssemaganda Vincent , Warnecke Gerald
Published: November 2019

We consider Riemann problems for a two-phase isothermal flow model of a dispersed phase in a compressible carrier phase. It is a weakly hyperbolic system of conservative partial differential equations. This model is the conservation part of a more complete physical model involving phase transitions in case both phases are of the same material. The purpose of this paper is to better understand the mathematical properties of the simplified model. We investigate the characteristic structure of the Riemann problems and construct their exact solutions. Solutions may contain delta shocks or vaporless states. We give examples for initial data corresponding to a system of water bubbles dispersed in liquid water. The analysis is complicated considerably by the fact that a liquid such as water requires an affine equation of state.
Reliable change in cognition over 1 week in community-dwelling older adults: a validation and extension study
Authors: Hammers Dustin B , Suhrie Kayla R , Dixon Ava , Porter Sariah , Duff Kevin
Published: November 2019

Objective

Reliable change methods can aid neuropsychologists in understanding if performance differences over time represent clinically meaningful change or reflect benefit from practice. The current study sought to externally validate the previously published standardized regression-based (SRB) prediction equations developed by Duff for commonly administered cognitive measures.

Method

This study applied Duff’s SRB prediction equations to an independent sample of community-dwelling participants with amnestic mild cognitive impairment (MCI) assessed twice over a 1-week period. A comparison of MCI subgroups (e.g., single v. multi domain) on the amount of change observed over 1 week was also examined.

Results

Using pairwise t-tests, large and statistically significant improvements were observed on most measures across 1 week. However, the observed follow-up scores were consistently below expectation compared with predictions based on Duff’s SRB algorithms. In individual analyses, a greater percentage of MCI participants showed smaller-than-expected practice effects based on normal distributions. In secondary analyses, smaller-than-expected practice effects were observed in participants with worse baseline memory impairment and a greater number of impaired cognitive domains, particularly for measures of executive functioning/speeded processing.

Conclusions

These findings help to further support the validity of Duff’s 1-week SRB prediction equations in MCI samples and extend previous research by showing incrementally smaller-than-expected benefit from practice for increasingly impaired amnestic MCI subtypes.
The founding of the RAS: the first meetings
Authors: Edmunds Michael
Published: November 2019

Mike Edmunds looks back almost 200 years to the first meetings of the RAS.
The Human Spaceship and other stories
Authors: Schell Helen
Published: November 2019

Artist Helen Schell writes about the research that goes into her projects bringing art into the exploration of the universe – and into science outreach.
Expanding worldviews: cosmic perspectives
Authors: Crawford Ian
Published: November 2019

Ian Crawford summarizes the second of two meetings exploring the relationships between astrobiology, big history and cosmic perspectives.
Protein docking model evaluation by 3D deep convolutional neural networks
Authors: Wang Xiao , Terashi Genki , Christoffer Charles W , Zhu Mengmeng , Kihara Daisuke
Published: November 2019

Motivation

Many important cellular processes involve physical interactions of proteins. Therefore, determining protein quaternary structures provide critical insights for understanding molecular mechanisms of functions of the complexes. To complement experimental methods, many computational methods have been developed to predict structures of protein complexes. One of the challenges in computational protein complex structure prediction is to identify near-native models from a large pool of generated models.

Results

We developed a convolutional deep neural network-based approach named DOcking decoy selection with Voxel-based deep neural nEtwork (DOVE) for evaluating protein docking models. To evaluate a protein docking model, DOVE scans the protein–protein interface of the model with a 3D voxel and considers atomic interaction types and their energetic contributions as input features applied to the neural network. The deep learning models were trained and validated on docking models available in the ZDock and DockGround databases. Among the different combinations of features tested, almost all outperformed existing scoring functions.

Availability and implementation

Codes available at http://github.com/kiharalab/DOVE, http://kiharalab.org/dove/.

Supplementary information

Supplementary data are available at Bioinformatics online.
A country road: domain name disputes in .nz—is private dispute resolution working?
Authors: Liddicoat Joy
Published: November 2019

Domain name dispute literature focuses largely on generic top level domains and the Uniform Dispute Resolution Policy. Country code top level domains (ccTLDs) attract far less commentary. This article addresses this gap with a detailed evaluation of one ccTLD dispute resolution system: .nz. Evaluation of domain name disputes presents unique challenges: there is no single system for resolving disputes, diverse legal tests apply across jurisdictions and categories of disputes vary. The article examines .nz in light of these challenges, developing and applying evaluation criteria to draw conclusions about the number and categories of disputes, resolution rates and overall effectiveness. The article analyses cases, including appeals, under the “unfair registration” test which contrasts with Nominet’s .uk dispute resolution policy on which the New Zealand system was closely modelled. The author concludes .nz operates a just and workable dispute resolution service that demonstrates effective and responsible ccTLD administration.
Exponential-Square Integrability, Weighted Inequalities for the Square Functions Associated to Operators, and Applications
Authors: Chen Peng , Duong Xuan Thinh , Wu Liangchuan , Yan Lixin
Published: November 2019

Let $X$ be a metric space with a doubling measure. Let $L$ be a nonnegative self-adjoint operator acting on $L^2(X)$, hence $L$ generates an analytic semigroup $e^{-tL}$. Assume that the kernels $p_t(x,y)$ of $e^{-tL}$ satisfy Gaussian upper bounds and Hölder continuity in $x$, but we do not require the semigroup to satisfy the preservation condition $e^{-tL}1 = 1$. In this article we aim to establish the exponential-square integrability of a function whose square function associated to an operator $L$ is bounded, and the proof is new even for the Laplace operator on the Euclidean spaces ${\mathbb R^n}$. We then apply this result to obtain: (1) estimates of the norm on $L^p$ as $p$ becomes large for operators such as the square functions or spectral multipliers; (2) weighted norm inequalities for the square functions; and (3) eigenvalue estimates for Schrödinger operators on ${\mathbb R}^n$ or Lipschitz domains of ${\mathbb R}^n$.