bluuebunny/crossref_metadata_2025 huggingface dataset:
Some consequences of unreported fishing on the results of simple fish stock assessment
Authors: Sondita M F A
Published: December 2019

Unreported fishing received less attention than illegal fishing but the later contributed the problem of data availability. Among various data needed for fish stock assessment, catch and fishing effort are popular for some preliminary analysis to describe annual trends of catch, fishing effort and catch per unit effort. Surplus production models can be used to determine the status of fish stock, maximum sustainable yield (MSY) and optimum annual fishing effort. Fisheries authorities then can determine some management measure promoting sustainability of the fisheries, such as total allowable catch. This study exercised some consequences of unreported fishing effort and catch data on the outputs of the assessment by a simulation with different levels of data using the model. The estimates of both MSY and optimum fishing effort were lower when catch and fishing effort were not fully reported. When the authority should firmly use the best available but limited data, their decision on the maximum annual catch and fishing effort will be more conservative. In contrast, their decision can be risky if over-estimated catch and fishing effort were used. If fishers expected fair levels of catch and fishing effort, the authorities can firmly ask them to provide data completely.
Evaluating the effectiveness of mangroves rehabilitation efforts by comparing the beta diversity of rehabilitated and natural mangroves
Authors: Rahmania R , Kepel T L , Arifin T , Yulius
Published: December 2019

Indonesia has lost 30% of the area over the past two decades due to anthropogenic activities. To overcome this problem, mangrove rehabilitation-which is generally interpreted as mangrove planting program - become the most popular option. These efforts could enhance the quantitative function (increasing mangrove areas extent and number of trees planted), yet the quality functions (biodiversity and ecological function) remain unclear. This analysis was carried out simultaneously with medium to high-resolution satellite image analysis to differentiate mangrove canopy pattern of these sites. The results showed that beta diversity value of mangroves in rehabilitation sites was lower than mangroves in natural area, which was characterized in satellite imagery as more uniform canopy and finer texture. Rehabilitation efforts that are mostly done through monoculture, are unable to produce an equal mangrove ecosystem function as natural mangroves do. This paper aims to examine the effectiveness of rehabilitation efforts whether they can develop an equal ecological function as good as natural mangrove ecosystem, by comparing the difference of beta diversity in two study sites which representing the natural (north Sulawesi) and rehabilitated mangrove (West Bali).
Restructuring steak from flakes of yellowfin tuna meat using low salt microbial transglutaminase (MTGase)
Authors: Ardiansyah A , Sahubawa L , Ustadi
Published: December 2019

Restructuring of fish meat can be done by using fragments of by-product processing such as fillet, loin, and steak of yellowfin tuna. The binder agent that may be the most efficiently used in restructuring the product is microbial transglutaminase (MTGase). Salt is needed to optimize the binding process of the restructuring product. The objective of the study was to determine the effect of low salt MTGase concentration as a binding agent on the quality of restructured yellowfin tuna steak compared to commercial yellowfin tuna steak. Research was designed with completely randomized design using 5 treatments in the 1.5% salt concentration, namely 0%, 0.3%, 0.5%, 0.7%, and 0.9%. The analyzed parameters were proximate (water content, protein, fat, carbohydrate, and ash), texture, colour and water holding capacity. The sensory test was conducted to compare restructured products with commercial tuna steak. The results indicated that the best treatment to the addition of MTGase was 0.5% based on the physical properties of the product, the nutritional content and sensory test. In sensory, MTGase was able to maintain the colour (brightness) of the products as they were darker than the commercial tuna steak and improve the product’s texture (hardness) in the addition of 0.9% MTGase.
Assessing stock status of grey sharpnose shark (Rhizoprionodon oligolinx Springer, 1964) in Java Sea
Authors: Wijopriono  , Ernawati T
Published: December 2019

Increasing demand for shark products leads to over fishing of these species in many areas, damaging their population. Grey sharpnose shark (Rhizoprionodon oligolinx) is caught mostly by gillnet fleet in Java Sea. The objective of the study was to discuss the current stock condition of grey sharpnose shark in Java Sea. Research on shark resources has been conducted by placing enumerators at the main landing base in PPN Pekalongan. Biological parameters of R. oligolinx were estimated based on commercial landings data recorded by enumerators from 2014-2015. The growth parameters of grey sharpnose shark such as L∞, K, t

0
, values were 96.1 cm, 0.47 year−1, and -0.78 year, respectively. Moreover, total mortality rate (Z) were estimated at 1.82 year−1 with fishing mortality and natural mortality rates (F and M) were 1.04 year−1 and 0.78 year−1, respectively. Stock status of grey sharpnose shark in Java sea from view point of gill nets fisheries is still in the sustainable utilization status with biological reference point more than 30% SPR and level of exploitation rate (E) is 0.57.
Purification of chitosanase from Stenotrophomonas maltophilia KPU 2123 and Micromonospora sp. T5a1 for chitooligosacharide production
Authors: Patantis G , Zilda D S , Fawzya Y N , Chasanah E
Published: December 2019

Stenotrophomonas maltophilia KPU 2123 and Micromonospora sp. T5a1 are bacterial strains isolated from shrimp waste capable of hydrolyzing chitosan to produce chitooligosaccharides (COSs). Their COS products showed antimicrobial activity. The aim of this study was to purify chitosanase from those bacteria and used for COSs production. Chitosanase from both strains were produced using 0.5% colloidal chitin as inducer. The chitosanase was then purified by ultrafiltration, DEAE Sepharose ion exchange and Separacyl S-300 gel filtration chromatography. The specific activity and the yield of chitosanase KPU 2123 increased 2.35-fold and 30.90% after three steps of purifications, respectively, whereas chitosanase T5a1 increased 3.32-fold and 22.79%, respectively. The molecular weight of both chitosanases KPU 2123 and T5a1 were about 76 and 20 kDa, respectively. The COS products generated by chitosanase KPU 2123 contained N-acetyl-D-glucosamine, Di-N-acetyl-D-glucosamine, Tri-N-acetyl-D-glucosamine, Tetra-acetyl-D-glucosamine and Penta-N-acetyl-D-glucosamine while by chitosanase T5a1 contained N-acetyl-D-glucosamine, Di-N-acetyl-D-glucosamine. Based on their COS products, chitosanase KPU2123 can be categorized as endo-type chitosanase. Further study is needed to analysis the bioactivity of COSs obtained from the pure of chitosanases KPU 2123 and T5a1.
Ecofriendly land-based spiny lobster (Panulirus sp.) rearing with biofilter application in recirculating aquaculture system
Authors: Thesiana L , Adiyana K , Zulkarnain R , Moersidik S S , Gusniani I , Supriyono E
Published: December 2019

The aim of the study was to create water treatment units for ecofriendly landbased spiny lobster rearing. Recirculating aquaculture system (RAS) is widely used because it is more environmentally friendly. Water quality requirement for spiny lobster cultivation are DO>4 mg/L and ammonia (NH3) less than 0.1/mgL. Attachment growth biofilter with sponge media used for reducing ammonia. Hydraulic loading rate 200 m3 m−2day−1 was used to evaluate biofilter TAN removal. Ammonia (NH3) concentration during the study range between 0.006-0.02 mg/L, total ammonia nitrogen 0.0-0.26 mg/L and DO concentrations at 6.29-6.54 mg/L. Volumetric TAN removal average value during the 24-hour observation was 23.33 g TANm3day and lobster survival rate reach 91.89%. This water treatment unit comply water quality requirements for lobster cultivation, and also can be used for other fishery commodities by adjusting their capacity to meet specific water quality standard.
On variations in turbine runner dynamic behaviours observed within a given facility
Authors: Gagnon M , Nicolle J
Published: December 2019

When confronted with cracks or high stresses in turbine runners, we often wonder if the behaviour observed on one specific runner will be present on all other similar runners. In this case, we have a facility with 19 runners having the same blade geometry. In order to answer the question, we selected three runners for measurement campaigns. First, the runners were divided in groups using band length, materials and wicket gate geometries. We then examined two runners with different wicket gate geometries and were thus able to explain why one runner exhibited recurrent fatigue damage problems and not the other. However, even within a given group, significant reliability differences were found when comparing with a third runner. The observed data shows that an important turbine characteristic was overlooked. Our conclusions point toward eccentricities and imperfections in the discharge ring attributable to only the upper part of the labyrinth seal being refurbished in this facility. This may generate a significant imbalance in the force produced by the flow in the runner side chamber. The paper underscores the impact of such imbalance, which could be present in older refurbished facilities.
Two-way strongly coupled fluid-structure interaction simulations with OpenFOAM
Authors: Doulcet Benjamin , Devals Christophe , Nennemann Bernd , Gauthier Maxime , Guibault François , Trépanier Jean-Yves
Published: December 2019

Predicting fluid-structure interaction phenomena is an ongoing challenge in numerical simulations. While we look for fast algorithms to solve the equations, some problems need a high accuracy in order to correctly predict results. Hence, controlling every aspect of the algorithm gives the possibility to optimise specific parts, potentially leading to greater accuracy. Developing such a numerical methodology can be achieved on an open source software such as OpenFOAM.
Dissolved-gas influence on the Francis part-load oscillation
Authors: Dörfler P K
Published: December 2019

A forced oscillation of system pressure occurs when a Francis turbine operates at partial load, typically between 50-85% of best-efficiency flow. Its cause is the precession of the draft tube vortex; due to cavitation of the vortex, the oscillation may enter in resonance. Predicting such a resonance from reduced-scale model tests is a long-standing goal of hydraulic research. Key parameter controlling the natural frequency of the underlying eigenmode is the compressibility of the cavitation zone. With the vortex cavity at vapor pressure, the natural frequency would scale by the same factor as the runner speed, thus enabling simple resonance prediction based on the model test. Based on experimental evidence, the actual pressure inside the vortex cavity is higher than vapor pressure, and the non-condensable gas content has significant influence. Due to uncontrolled variation of cavity pressure, the natural frequency in model tests may deviate by as much as 30% under nominally identical conditions. A 1D mathematical model can represent the influence of non-condensable gas on the cavity volume and compliance; even quite moderate cavity pressures explain the observed discrepancies.
Recent developments in unsteady pipe flow experimentation at the University of Montenegro
Authors: Brđanin R , Karadžić U , Bergant A , Ilić J
Published: December 2019

This paper presents recent experimental results of pressure measurements during filling and emptying of a relatively small-scale pipeline at the University of Montenegro. Experimental setup for investigation of water hammer and its special effects (unsteady friction, cavitation, column separation, trapped air, fluid-structure interaction - FSI), and pipeline filling and emptying is installed at the Faculty of Mechanical Engineering. It consists of an upstream end high-pressurized tank, horizontal steel pipeline (total length: 55.37 m, inner diameter: 18 mm, pipe wall thickness: 2 mm), four valve units positioned along the pipeline including the end points, and a downstream end outflow tank. The setup was upgraded in 2018 with the installation of new piezoresistive pressure transducers and pipe displacement sensors as well as additional electro-pneumatically operated ball valve at the upstream end of the pipeline. The filling of an initially empty pipeline is performed by a sudden opening of the valve positioned at the high-pressurized tank filled with water. The pipeline emptying process is accomplished by high-pressurized air supplied from the air reservoir installed in the air supply line. The high-pressurized tank is closed, and the downstream end valve is opened. Experimental runs have been performed with different initial values of pressure in the upstream end high-pressurized tank (filling) and air supply line (emptying). Results of new pressure measurements are analyzed and commented, with a reference to the previous experiments presented at 6th IAHR WG Meeting in Ljubljana, 2015.
Tin (Sn) whisker growth from electroplated Sn finished
Authors: Hashim Aimi Noorliyana , Salleh Mohd Arif Anuar Mohd , Mokhtar Noor Zaimah Mohd , Idris Shahida
Published: December 2019

Electroplated tin (Sn)Limeited finishes are widely used in the electronics industry due to their excellent solderability, electrical conductivity and corrosion resistance. However, since prohibiting the use of lead (Pb) in electronics, the issue of tin (Sn) whisker has become one of the most imperative issues that need to be resolved. Moreover, with the increasing demand for electronics miniaturization, Sn whisker growth is a severe threat to the reliability of microelectronic device. This paper investigates the effect of electroplating current density (10, 30 and 50 mA/cm2) on whisker growth at room temperature. A simple micro- indentation test was used to accelerate continuously the growth of Sn whisker at room temperature storage for 24 h. Morphology analysis of Sn whisker growth was done using scanning electron microscope (SEM) and image-J Software. Axial length of the Sn whisker was calculated by using JEDEC Standards (JESD22-A121A).
Interfacial reactions between different Sn-based lead- free solder alloys and CuNi substrates
Authors: Razak Nurul Razliana Abdul , Tan Xin Fu , McDonald Stuart D. , Nogita Kazuhiro
Published: December 2019

The effect of the presence of Ni in Cu substrates on the interface reaction during soldering and the growth of Sn-Cu intermetallic compounds (IMCs) was studied. The study involved reflow soldering of Sn-0.7Cu, Sn- 3Ag-0.5Cu and Sn-0.7Cu-0.05Ni lead-free solders on pure Cu and Cu-6Ni substrates with holding times of 5, 10 and 15 minutes at 232 °C. The presence of 6 wt% Ni in the Cu substrate strongly affects the microstructural evolution and the growth of the IMCs. The presence of Ni in the substrate significantly increased the overall thickness of the (Cu,Ni)6Sn5 layer while suppressing the formation of the Cu3Sn layer. The thickness of the (Cu,Ni)6Sn5 layer increased with reflow time for both Cu and Cu-6Ni substrate.
Recovery of tin from copper dross by acid leaching
Authors: Jabit Nurul Ain , Ismail Suhaina , Azhar Muhammad Alif Noor
Published: December 2019

Copper dross(CD) is a waste product formed during copper doping where sulphur was added to the tin metal during refining process to remove copper in the form of copper sulphide. CD was found to contain significant amount of tin and other valuable metal such as copper that could be trapped during copper doping process. The main objective of this work is to assess the potential of CD as a secondary resource for tin product and the applicability of hydrometallurgical process to extract tin and copper. Two main parts involves in this work are CD characterization and recovery of tin by acid leaching. From elemental composition analysis by XRF, in CD sample, amount of SnO2 present is about 63% followed by SO3 with 14%, Fe2O3 is 9% and CuO with 2.5%. Cassiterite and magnetite is the main phases found by XRD analysis. From the leaching study, it was found that almost 60% of tin has been dissolved in acid solution at condition of 80 °C, 2 M HCl with 8 hours leaching time.
Graphitization damage on seamless steel tube of pressurized closed-loop of steam boiler
Authors: Hayazi Nur Farhana , Shamsudin Shaiful Rizam , Wardan Rajaselan , Sanusi Mohd Syazwan Muhamad , Zainal Farah Farhana
Published: December 2019

The pressurized closed-loop of steam boiler has been in operation for five years has experienced leakage problems at the bottom of the reducer and at the center of the tube on weldment. The metallographic analysis found that the leakage was due to the degradation of microstructure as a result of long-term overheating. The degraded microstructure of the tube boiler material dominated by graphitization. The graphitization normally applicable at 450°C, but with high-pressure water flow (90 bar) in the combination of internal stress on the tube material due to the welding process as well as the formation of the reducer, making the boiler operating temperature is sufficient to produce graphitization. The leakage occurred when the chain and accumulated graphitization happen because the cavities that covered the graphite facilitates the cracking propagation due to the presence of stresses.
Influence of filler content and mixing time on the properties and morphology of kenaf/polyurethane foam composites
Authors: Soberi Nur Suhaili Mohd , Rozyanty A. R , Zainuddin Firuz , Osman A.F
Published: December 2019

Kenaf/polyurethane foam composites were prepared at percentage of 2, 4, 6 and 8 wt% of kenaf fiber. Free rising polyurethane foam was prepared at constant (NCO/OH) ratio 1.5:2, while water was used as blowing agent. The mixture was stirred at 400 rpm using mixing times of 20 and 25 seconds. Rise time and hardness of the composites was determined. From the results obtained, rise time and hardness of polyurethane foam composites were reduced at 25s mixing time. However, as kenaf core fiber increase, the rise time decreased and the hardness of the foam composite increased. The Scanning Electron Microscopy (SEM) analysis evidenced the presence of regular cell shape and uniform cell size in the kenaf/polyurethane foam composites. The findings indicate the potential of using kenaf fiber to enhance the properties of the polyurethane foam.
Influence of the structural design of rail fastenings on ensuring the stability of track gauge in operating conditions
Authors: Aharkov O V , Tverdomed V M , Boiko V D , Kovalchuk V V , Strelko O H
Published: December 2019

As the rolling stock speed increases, the requirements for stability parameters increase accordingly. One of these parameters is the track gauge. The stability of this parameter depends on many of the structural elements of the upper track structure and on the environmental conditions. In the research work, the authors have considered the influence of such a structural element as an intermediate rail fastening on its ability to provide a stable track gauge. The most common intermediate rail fastenings on the Ukrainian Railways have been accepted to be compared, including the KB-65 type fastening, the KPP-1 type fastening and the KPP-5 type fastening. In order to determine exactly the influence of each structural element, the other gauge parameters for all three types of fastenings have been taken equivalent. The data have been obtained from the track measuring car. With the obtained data, a statistical analysis has been conducted, which enables to draw conclusions about the ability of the intermediate rail fastenings under consideration to ensure the track gauge stability. The conclusions have been made on the applicability of each of the fastenings under consideration.
Methods of Imposing Restrictions on Land Management in Planning of an Airport’s Transport Infrastructure
Authors: Dobryak D.S. , Novakovska I.O. , Nikolaiev K.D. , Skrypnyk L.R.
Published: December 2019

Aviation transport can have a significant impact on the environmental conditions of land adjacent to the airport. To achieve the purpose of the article, a set of general scientific and special methods of research was used, in particular: monographic analysis, abstract-logical, systematic approach, calculation and graphical, mathematical. The concept of ecological and economic assessment of land management restrictions for airport infrastructure is analyzed, since the legal regime and the specificity of their use are strictly regulated by legislative norms and standards. The assessment of constraints on the functioning of airport infrastructure should reveal the impact of transport accessibility on the environment of the airport and the growth of the economic development of the neighboring region. The need to model the future demand for motor transport around airports is justified, which requires the accuracy of forecasting any future trips to airports, for example, due to economic profit after the increase in local traffic, driven by population growth, demand for real estate ownership and business development. The principles of open space preservation and integration with adjacent transport routes are considered, taking into account the aesthetic expediency and meeting the needs of the population when forecasting, planning and designing the airport infrastructure. Preservation of the open space around the airport shall be controlled constantly to ensure proper functioning and development of the approach roads thereto. The results of the study are proposals for the implementation and application of the following principles of environmental and economic assessment of design solutions in the context of the interconnected operation of the aviation enterprise and territory around the aerodrome.
Assessment of the ecological state of soils in roadside territories using chemical and biological indication
Authors: Iurchenko V O , Ugnenko I B , Melnikova O G , Rachkovskiy O V , Ivanin P S
Published: December 2019

Chemical and bioindication studies of soils in the roadside areas of railways and highways have been carried out. The studies have shown that on the territories directly adjacent to the transport routes, the concentrations of the petroleum products in soils are 1.6-32.4 times exceeding the APC (approximate permissible concentration). The most substantive exceedances of the APC are recorded in the highways roadside spaces. We have investigated the dependence of the petroleum products concentration in the soils and their bioindication indices on the distance to transport routes. It has been established that the pollution of roadside soil by petroleum products decreases sharply at a distance of 10-15 m from transport routes. And bioindicators show different dynamics with increasing distance from the source of pollution (and, consequently, decrease in concentration of petroleum products in soils): the intensity of respiration of soils increases, and catalase activity decreases, which reflects its characteristic as an enzyme of stress.According to bioindication data, it has been shown, that the soils of the roadside space (especially, as for railways) retain high restorative potential.
System of designing livestock small-volumetric cooperative buildings
Authors: Nesterenko S V , Shchepak V V , Kariuk A M , Mishchenko R A
Published: December 2019

It was determined that the design system for livestock small-scale cooperative buildings is formed under the influence of a significant number of different factors, since it is necessary to take into account the adaptation of buildings to the environment and the peculiarities of the organization of their internal environment. In addition, livestock buildings have differences depending on functional characteristics, design solutions, used building materials, etc. An innovative solution that takes into account the variety of characteristics of the building’s internal environment as much as possible is livestock breeding low-volume cooperated buildings. These buildings have the specifics of functioning in the external environment, so the formation of an appropriate design system is necessary. For the effective functioning of such a system, its components consolidated on the basis of modeling. The design system model for livestock cooperative small buildings was developed taking into account the multifactorial influence of the external and internal environment of buildings, as well as design conditions, and the main components of the system were determined, the relationships between them and their characteristics. The proposed model of a design system for livestock low-volume cooperated buildings shows the interdependence of its components and describes the parameters of their interaction.
Reliability design of rotors for orbital hydraulic motors
Authors: Panchenko A , Voloshina A , Panchenko I , Titova O , Pastushenko A
Published: December 2019

The reliability of orbital hydraulic motors which are used in mechatronic systems with a hydraulic drive for active working tools on self-propelled machinery is a pressing engineering problem. To increase the reliability, a specific design method was proposed. It required development of a mathematical apparatus and a calculation algorithm. The mathematical tools allowed to realize the method for determination of hydraulic motor reliability by simulating changes in a technical state of the rotors in a hydraulic motor. A program, which has been developed, enabled modeling the conjugation of external and internal rotors. The program implemented an algorithm for the sequence of calculating the parameters for the external and internal rotors. The proposed program made it possible to obtain a three-dimensional image of zones with admissible interfaces which ensure the efficient and reliable operation of orbital motors. The modeling of working capacity change for an orbital motor has established some dependence. The changes in the number of teeth and overall dimensions of the rotor in the investigated range enabled to develop a standard size range for hydraulic machines, which operate in mechatronic drive systems for active working tools on self-propelled machinery.
About one aspect of effective building of bus traffic schedule with an approximate algorithm
Authors: Panishev A V , Kostikova M V , Skrypina I V , Levterov A I
Published: December 2019

The assignment problem belongs to the main tasks of combinatorial optimization. This is a special case of the transport problem. Special methods that allow finding the optimal solution from the set of possible ones have been developed for solving the transport problem. The assignment problem is used in transport to optimize the arrangement of the cars along the routes, in the process of distributing the drivers among the cars, and in the process of distributing freights along the production lines. This article considers the case when m n < during the search of optimal solutions in the assignment problem of a transport type. The authors offer an algorithm that allows us to build a bus schedule taking into account the current restrictions in the presence of which the passenger traffic is carried out. A theoretical assessment of time complexity of an offered procedure for constructing all optimal solutions to the assignment problem is presented. An example illustrating the operation of the constructed algorithm, which allows finding the whole set of optimal solutions in polynomial time is given. Recommendations on the use of the algorithm in practice are given.
GIS in the study of transport infrastructure of technogenic-deformed territories
Authors: Penkov V O , Astakhov V N , Sayapin A S , Bielikova N V , Bielikov E A
Published: December 2019

Timely application of GIS technologies is determined by the need to create an intelligent digital control system for spatial surveying and road data in combination with information resources about the real state of infrastructure facilities. It is necessary to use the techniques of data collection, processing, and analysis corresponding in accuracy, reliability, and efficiency, such as the tasks set for the GIS, as well as modern capabilities of computer technology and software. The current lack of the concept and methods of geoinformational support for the functioning of the transport infrastructure of cities in technogenic-deformed territories (TDT) makes the solution of this issue relevant. Today, it is technically feasible to create a space-time model of deformation processes based on data from many years of field studies also using methods of mathematical modeling of mining processes and surveying calculations. The main method of research is the analysis of field studies using GIS modeling, using mathematical and statistical methods. The source data are published materials of long surveying and geodetic observations and statistical materials created in previous years by various organizations of Ukraine.
Comparative analysis of the parameters of the strength of the subgrade at the transition to the higher axial loading up to 25 t
Authors: Radkevych A V , Petrenko V D , Tiutkin O L , Andrieiev V S , Mukhina N A
Published: December 2019

A review of the scientific and technical literature on the re-alignment of the route during the transition to high axial load from the accepted today (23.5 t/axis) to the perspective (25 t/axis) shows that in the stage of preliminary researches imitation modeling of the earth web by the finite element method (ITU) as the most convenient, accurate and illustrative of the known numerical methods. In order to provide recommendations on the strength of the subgrade when moving to a higher axial load up to 25 t/axis, an analysis was conducted, the essence of which was to compare the stress-strain state of the subgrade at two loads per axis: 23.5 t/axis (existing ) and 25 (perspective). All the geometric and deformation characteristics of the formation are taken from data on a two-track section with a height of embankment of 3. The deformation characteristics are chosen so that the working material of the formation is in accordance with the average indices of deformation capacity of the railways used. The ITU train load calculus makes it possible to obtain all the factors of VAT in it, which is the main purpose of the study of the strength of the earth cloth, and allows to forecast their development in the future.
Process features and parametric assessment of the emergence of the excessive wear for the brake pads of freight car bogies
Authors: Ravlyuk V , Ravliuk M , Hrebeniuk V , Bondarenko V
Published: December 2019

The article presents a new scientific approach to the problem related to the specific nature of the adverse biplanar critical friction wear profile of brake pads which is quite common in cars of Ukrzaliznytsya JSC, as well as in many countries where the so-called three-element bogies are used. In order to study the dual wear of brake pads during the operation, the statistical material was collected and processed in the specialized software STATISTIKA to obtain graphical dependences that confirm the results of theoretical research. In the conducted studies, the concept of dual friction wear of brake pads was first discovered as a phenomenon and introduced. The stages of formation of especially harmful wear on the working surfaces of brake pads causing the complex formation of adverse specific dual wear are shown. A new concept of the duality coefficient of frictional wear of brake pads has been introduced, and a formula for its calculations has been proposed, which has been tested in the calculations of the values of brake pressures of pads with dual wear to support the analytical studies.
Research of the calculation scheme for the brake lever transmission and construction of the load model for the brake pads of freight cars
Authors: Ravlyuk V , Ravliuk M , Hrebeniuk V , Bondarenko V
Published: December 2019

In the article, the points of load application effecting the pads and other parts of the freight car three-element bogie during braking is considered theoretically using the example of the 2D diagram of the brake rigging. The special differences between the operating conditions of the first and second triangles of the car brake rigging and their effect on the wear of the pads when the train is moving without braking are described. The different operating conditions of the triangles are described to establish a causal relationship regarding the abnormal wear of the brake pads of the three-element bogies. For the first time, a calculation algorithm of a more accurate approach to theoretical calculations was proposed to determine the actual pressing forces in the brake pads on the wheels of the bogies. It proves the existence of the theoretical error, which is now inherent to the design models of freight cars brake rigging elements. The obtained algorithmic equations will help assess the wear of the brake pads and its effect on the stress-strain state in order to guarantee the railway traffic safety during the relevant theoretical and practical studies.
Methodological bases of assessment of lands of a populated item, taking into account the influence of road networks
Authors: Tokarev M N , Dobrokhodova O V , Nesterenko S H , Radzinska Y B , Chubukyn R Y
Published: December 2019

The content of regulatory documents of Ukraine on the zoning of the territory of a settlement is analyzed. The possibility of using open geographic data to perform the above work is considered. The quality criteria of residential areas are established. Technique for a comprehensive point assessment of the territory based on weighted average indicators, including the results of mathematical GIS analysis of the territory and data of subjective expert assessment has been developed. The conducted GIS analysis of the territory clearly demonstrated the effectiveness of the integrated assessment method because it combines both a rigorous mathematical assessment of the mutual arrangements of the city elements and the subjective opinion of individuals. The practical use of the results of the assessment allows us to identify places of long-term development on the territory of the city, plan transport infrastructure, and establish technical and economic indicators for measures to develop urban infrastructure.
The use of intermittent wheels, impregnated by the contact method to reduce the thermal stress of the grinding process
Authors: Tonkonogyi Vladimir , Yakimov Alexey , Bovnegra Liubov , Sidelnykova Tetiana , Dašić Predrag
Published: December 2019

The proposed composition of solid technological lubricant applied to the working surface of the abrasive wheel directly in the grinding process. Experimental studies have been carried out to identify the effect of implanting on the normal and tangential components of the cutting effort and temperature that occur when grinding with abrasive wheels with continuous and intermittent work surfaces. It is established that when grinding with impregnated intermittent circles, the magnitude of the ratio Fz/Fy normal to the tangential component of the cutting force is less than when grinding with impregnated wheels with a solid working surface. It was established experimentally that the impregnation of the working surface of intermittent wheels reduces the thermal stress of the grinding process and increases the number of actively working grinding grains. The decrease in the Fz/Fy ratio during intermittent grinding with an impregnated wheel compared to dry intermittent grinding can be explained by a decrease in Fz with a simultaneous increase in Fy. A decrease in temperature when using solid lubricant indicates a decrease in the coefficient of friction of grinding grains with the processed material and, therefore, a decrease in the tangential component of the cutting force Fz. An increase in the number of actively working grains during grinding with intermittent impregnated circles compared to dry intermittent grinding indicates an increase in the normal component of the cutting force Fy. It is established that the maximum temperature during grinding with impregnated intermittent circles shifts towards the rear point of the contact arc compared to dry grinding, where the temperature reaches its highest value near the front point of the contact arc of a circle with the material being processed.
New design concepts for strengthening of continuous reinforced-concrete beams
Authors: Azizov T N , Kochkarev D V , Galinska T A
Published: December 2019

The present article is concerned with basic methods of reinforcement of continuous reinforced-concrete beam constructions. The main disadvantages and difficulties in strengthening such load carrying structures have been identified in this academic paper. There has been offered the method of reinforcement of continuous reinforced-concrete beam constructions. Besides, the authors have established the procedure of designing effective continuous reinforced-concrete beams in case of the reinforcement. The basic principle of enforcement of continuous reinforced-concrete beams is proposed in this exploratory development. This principle lies in the fact that it is necessary to find the desired span stiffness of continuous reinforced-concrete beam constructions, which would provide sufficient reinforcement in the reference section of the beams. In this case, there is no need to strengthen reference sections, which is practically impossible to do in most instances without dismantlement of the existing concrete floor slabs. For reinforcement systems designing, it is proposed to use the method of design resistance of reinforced concrete, which uses theoretically, and experimentally confirmed prerequisites and hypotheses. The calculations are made by the iteration method. There has been provided a calculation example of enforcement of continuous reinforced-concrete beam constructions using the proposed method.
Calculation of turning rigidity of I-section reinforced concrete elements with normal cracks
Authors: Azizov T N , Orlova O M , Nahaichuk O V
Published: December 2019

The article provides a methodology for calculating the torsion of an I-beam element using its approximation in the form of a cross-rod system. The cross-sectional I-section is divided into a finite number of longitudinal rods of rectangular section. These rods focus on their axial, flexural and torsional stiffness. Longitudinal rods are connected by transverse vertical and horizontal rods. The transverse rods imitate the local deformation of the longitudinal rods at their contact with each other. In contrast to the previously proposed methodology, in order to reduce the number of unknowns for creating the basic scheme of a statically indeterminate system, it is proposed that not all transverse rods be cut, but only one step in the longitudinal direction. The forces in the longitudinal rods determined from this calculation are applied to the rods of the next step. The pitch of the transverse rods may be arbitrary. A method for determining the stiffness parameters of the rods of an approximating system is shown. The advantages of the proposed methodology are shown, which can significantly reduce the number of equations unknown in the system, calculate elements for bending with torsion, and also take into account the change in stiffness as a result of nonlinear work of materials and crack formation.
The destruction of buildings walls brickwork on an unevenly deformed base
Authors: Kichaeva O , Dobrokhodova O
Published: December 2019

The article is dedicated to the analysis of the results of experimental testing of brick structures resistance. The experimental testing aimed at revealing a qualitative pattern of deformation and the character of losing the bearing capacity of a system “brick beam-wall – deformed base” and obtaining quantitative data about the strained and deformed state of the system undergoing short-term force and deformation at all stages of loading. Revealing the structure and phases of deformation and destruction of brickwork subjected to the increasing loading and the construction of dependences “loading – deformation” corresponding to the process of brickwork deformation and destruction was also an important task. It has been proved that the mechanism of the destruction of brick structures walls fragments, supported by uneven deformed base, occurs according to the scheme of shear, cut and breaking to pieces, as well as destruction of brick material and mortar with clear determination of deformation stages and brickwork destruction. The results of analysis of the experiments allowed to determine the influence of the amount of loading acting on cracks formation and brickwork functioning as a whole.
About need of calculations for the steel framework building in temperature influences conditions
Authors: Otrosh Y , Semkiv O , Rybka E , Kovalov A
Published: December 2019

In the article a technique of studying technical condition for steel structures that were damaged by high temperature impact, as well as a climatic effects on building structures due to the difference in ambient temperatures is described. Based on obtained data, there was made a conclusion about technical condition of the structures and possibility or inability to restore their serviceability by repair, reinforcement or replacement. There were conducted a comparative analysis of the results of experimental studies and numerical analysis. The mathematical model makes possible operative prediction for the controlled parameters values of building structures. In the article, examples about practical application of the techniques are described that allow doing technical examination of objects, damaged by temperature influence. The aim of this study is to substantiate the need to make calculations about temperature impacts for buildings with a steel frames and to develop measures to ensure the serviceability of steel structures of buildings and structures in conditions of temperature impact.
Soil stabilization with modern TM MAPEI materials in reconstruction of buildings and structures
Authors: Panchenko S V , Vatulia G L , Lobiak O V , Pavliuchenkov M V , Herasymenko O S , Bohdan S M
Published: December 2019

The article deals with the findings of experimental and theoretic research into the efficiency of applying prepared substances TM MAPEI for chemical soil stabilization for foundations of buildings in reconstruction. The objects of the study were soils of rapid, average and slow permeability. Determination of physical and mechanical characteristics of soils before and after stabilization was conducted in laboratory environment. The results were obtained on the basic of the project into stabilization of foundations under complex reconstruction of a four-storied building. The chemical stabilization technology for foundations purported uniform mixing of soil with a special mixing screw, supplying needed components, and further consolidation. A design diagram for the building was made in software package Lira-SAPR 2018. Calculations of carrying capacity of the foundation were made for six design patters which differed in characteristics of the stabilized soil according to the materials applied. The first design pattern considered the application of non-stabilized soil. Results of the calculations are presented as isofields, soil reaction coefficients C1
and C2
, loads (pressure) on the foundation Pz
, and vertical deformations. On the basis of the research the authors state that application of TM MAPEI for chemical stabilization of collapsible soils under reconstruction allows increasing the foundation rigidity by three times and more, the carrying capacity by 10 times and more, depending on the formulations accepted.
Energy resource of reinforced concrete elements and structures for the deformation-force model of their deformation
Authors: Romashko V M , Romashko O V
Published: December 2019

This article provides a critical analysis of existing methods for calculating the residual life of reinforced concrete elements and structures by the rigor of the original problem statement and how it is solved. The most important provisions of the universal method of calculating the residual energy resource of reinforced concrete elements and structures under conditions of long operation are outlined. It is based on the deformation-force model of resistance of reinforced concrete in general and the hypothesis of invariance in unit volume and independence from the mode of loading of potential energy of deformation of reinforced concrete element. This hypothesis is reformed to the energy criterion of exhaust bearing capacity of reinforced concrete elements under different load modes. The implementation of the proposed method for calculating the residual energy resource of the bearing strength capacity of reinforced concrete elements and structures is possible also in a temporary dimension. This can be done using the concrete creep parameters.
Model of multilevel formation of normal cracks in reinforced concrete elements and structures
Authors: Romashko O V , Romashko V M
Published: December 2019

This article proposes a model of multilevel formation of normal cracks. It is based on the most important patterns of adhesion of reinforcement with concrete. The occurrence of the first normal cracks of the first level is calculated by the limiting deformations of stretched concrete, which are fixed by the extreme criterion of its strength. The distances between the cracks are determined by the equilibrium of the maximum forces in the stretched concrete and the forces of active adhesion in the area between the cracks. It is proposed to calculate the force of active coupling by the nonlinear function of the average stresses of this coupling, justified by the power of expression. It is substantiated why for bending reinforced concrete elements the distances between normal cracks of new and previous levels will always differ from each other. In the developed model, the width of the most dangerous normal crack opening is calculated from the positions of successive accumulation of reinforcement and concrete mutual displacements.
Crack resistance of decorative composites
Authors: Dovgan A D , Vyrovoy V M , Dovgan P M
Published: December 2019

The results of a study of crack resistance obtained during the development of fine-aggregate concrete for architectural elements are presented. The crack resistance study of 27 different proportions of compositions was carried out in accordance with DSTU B V.2.7-227: 2009 using experimental statistical modeling methods. Due to the fact that the method of initiating the initial crack in the samples changes the distribution of the technological fields of strain, the tests were carried out on two series of samples. The data obtained show that the crack sealing method changes the deformative-stressed state of the composite. So, crack resistance for one concrete composition can vary, from the conditions of the experiments, from 3 to 40 %. Based on the obtained values of the characteristics of the material, in particular, for the coefficient of technological impact on crack resistance, which describe the fields of these criteria in the coordinates of the factors of concrete composition, models were built. The results of the model are presented on 5 factor diagrams of the form “cubes squared”. An analysis of the constructed diagrams showed that the initial conditions for the organization of the structure of concrete determine its ability to resist the development of various types of cracks. During the introduction of finely dispersed fibers at an optimal dosage of fine sand grains (50 % in a sand mixture) and a slight replacement of cement with zeolite (from 2 to 3.4 %), it is possible to reduce the technological damage to the decorative composite, thereby improving crack resistance.