bluuebunny/crossref_metadata_2025 huggingface dataset:
Stochastic Time series analysis of Runoff data of the Blue Nile at Eldeim, Sudan
Authors: Eldaw Elsiddig , Huang Tao , Mohammed Adam Khalifa , Muhama Yahaya
Published: January 2019

To improve the management of operation system for the Roseires reservoir it is necessary to know the hydrological system of the Blue Nile river, which is the main water source of the reservoir. In this work, a Modified Thomas Fiering model for generating and forecasting monthly flow is used. The methodological procedure is applied on the data obtained at the gauging station of Eldeim in Blue Nile, Sudan. The study uses the monthly flows data for years 1965 to 2009. After estimation the model parameters, the synthetic time series of monthly flows are simulated. The results revealed that the model maintained most of the basic statistical descriptive parameters of historical data. Also, the Modified Thomas Fiering model is applied to predict the values of the next fifty-five years, with excellent results that conserved most basic statistical characteristics of runoff historical series. The Modified Thomas Fiering model is able to realistically reconstruct and predict the annual data and shows promising statistical indices.
Experimental study on incipient condition of fluidized bed sediment in oscillatory
Authors: Wang Rui , Yu Guoliang
Published: January 2019

In this paper, the incipient condition of the fluidized bed sediment with different sizes and water contents were experimentally studied in an os- cillatory tunnel made of acrylic boards. One-hundred experimental runs were performed with sediment samples by varying the yield stress to determine the relationship between the critical condition of incipient motion and the rheolog- ical properties of the cohesive sediments. Experimental results showed that the yield stress of the bed sediment decreased as the fluidization level increased. When the yield stress is no longer changed, the bed sediment was considered completely fluidized. In oscillatory flow, the critical shear stress decreases with the increase of fluidization level. When the bed sediment reaches the full flu- idization state, the critical shear stress of the bed sediment at the bottom re- mained constant. For cohesive sediments, in the case that particle size and bulk density were known, the relationship between the yield stress and the critical shear stress was analyzed, and the incipient condition of the cohesive sediment under oscillatory flow action was determined.
A model for soil moisture dynamics estimation based on artificial neural network
Authors: Wang Wei , Wang Shuya , Chang Jianxia , Bai Dan
Published: January 2019

Research on soil moisture estimation models can effectively improve the growth environment of crops. In this paper, the author studied the artificial neural network and variation pattern of soil moisture. Then, application of the model for water diversion estimation was explored based on artificial neural network. On this basis, an optimization algorithm was presented to simulate water diversion. Furthermore, a model for remote sensing of soil moisture dynamics was applied to artificial neural network. It has been proven that the research can optimize the application of the proposed model, laying a solid foundation for future study.
Synchronous asynchronous encounter analysis of runoff between reservoirs based on Copula function
Authors: Zhao Weidong , Zhang Jing
Published: January 2019

Based on goodness-of-fit test on Copula function, we got the best fitted joint distribution function of runoff between D and H reservoirs. Then we analyzed the synchronous asynchronous encounter probability of runoff. The synchronous encounter probability of runoff was 72.46%, while the asynchronous of dryness-wetness or wetness-dryness encounter probability was only 1.06% between D and H reservoirs. The results showed that the runoff conditions were not conducive to the runoff compensation. In order to satisfy the target of water supply, we should also study the reservoir optimization operation, store water in advance and exploit the reservoir regulating potentialities on flood water resources.
Application of the ‘CPT 2012’ model of AFNOR standard for column design in Poland – Jazowa case study
Authors: Bałachowski Lech , Konkol Jakub , Międlarz Kamila
Published: January 2019

This paper presents the ‘CPT 2012’ model incorporated into the AFNOR NF P94-262:2012-07, French standard for pile design fully compatible with Eurocode 7, to the wider Polish audience. The bearing capacity of three reference columns for Vistula Marshlands have been calculated according to ‘CPT 2012’ model and AFNOR recommendations. Then, the design resistances have been compared with ultimate column bearing capacity measured during static load tests conducted on reference columns. The results of comparison are discussed and the discrepancies between measured and calculated bearing capacities are shortly commented.
Stability estimation of slopes with determined slip surface by the MSTAB-3D method based on sliding body limit equilibrium analysis
Authors: Ukleja Janusz
Published: January 2019

The method developed for this study, established on the premises of the limit equilibrium flat analysis for a spatial solution, is a modification of the STAB-3D method, previously described by the author. It combines the analyses methods of 2D slices of flat cross–sections with the spatial analyses methodology rooted in a specific breakdown of a landslide sliding body into 3D elements assuming some simplifying solution. However, this method is solely applicable in case of a landslide failure with a stipulated slip surface and with a consistent decline of a determined slide direction. Such a method was developed in the article published earlier, which provided then its basic assumptions and the equilibrium formulations. The following publication thereof, presents overall suppositions for this method as well as its modification involving the resultant forces brought to the equilibrium with the generalized slide direction. Apart from that, a comparative analysis was carried out on the impact of this modification applicability of the obtained results with regard to the STAB-3D method. The algorithm was also presented concerning the modified method with its results being compared to a couple of selected methods LEM (limit equilibrium method). The undertaken analysis reveals that the modified MSTAB-3D method determines stability indicators that are very similar to its earlier version. Moreover, the results occur to be also approximating the values obtained in the course of other methods with regard to the flat cross-section analysis.
Characteristics of the complex modulus of recycled cold mix with foamed bitumen and recycled concrete aggregate
Authors: Buczyński Przemysław , Iwański Marek
Published: January 2019

This article presents research on recycled cold mix with foamed bitumen (MCAS) containing recycled concrete aggregate. The primary concept driving this research was to determine if recycled concrete aggregate (RC) could be used as a substitute for reclaimed asphalt pavement (RAP). Recycled concrete aggregate was used in the MCAS mix in amounts ranging from 20%, 60% and 80%. The reference mix was the MCAS mix containing 50% reclaimed asphalt pavement (RAP) and virgin aggregate. Identical 0/31.5-mm continuously graded dolomite virgin aggregate was used in all mixes. 2.5% foamed bitumen (FB) and 2.0% CEM I 42.5R Portland cement (PC) were used to increase the cohesion of the mineral mix. Foamed bitumen was produced from 50/70 penetration paving bitumen. The behaviour of the recycled base course was tested in the range of cyclic sinusoidal strain with amplitude εo = 25–50 με. The tests were carried out in the (-7°C, 5°C, 13°C, 25°C, 40°C) temperature and (0.1 Hz, 0.3 Hz, 1 Hz, 3 Hz, 10 Hz, 20 Hz) loading time range. The complex modulus was tested in a direct tension-compression test on cylindrical samples (DTC-CY) in accordance with EN 12697-26. The results of the tests were used to assess the complex modulus (E*), phase angle (φ) and complex modulus components (E1) and (E2).Tests of the mixes indicate that recycled concrete aggregate can be used in recycled cold mixes in amounts of up to 80%. Increasing the amount of recycled concrete aggregate does not cause excessive stiffness of the recycled mix in comparison with the reference mix. The tests did not demonstrate a significant difference in terms of the phase angle (φ), which indicates a similar content of the viscous part and elastic part in the obtained complex modulus for the reference mix (RAP + MCAS) and the mix containing recycled concrete aggregate (RC + MCAS).
Studies on the impact of the technical characteristics of local roads on road safety
Authors: Gaca Stanisław , Kieć Mariusz
Published: January 2019

Local roads (district roads) constitute an important part of the road network in Poland, making up around 29.7 % (124,945 km) of all public roads. In 2017, 10,578 accidents, which is 35.7% of all accidents in Poland, took place on local roads. These roads are used primarily by regular users who are very familiar with the defects of these roads. This means that the effects of the low technical standard of local roads and the insufficient number of road traffic devices on the safety on the road can be partly compensated for by the fact that drivers adjust their behaviour to the conditions on the road. This hypothesis can be verified through developing dependency models of road safety measures of local roads’ and technical characteristics. The article presents the research carried out based on regression models of accident prediction. The models were developed with the use of the data on the road surroundings arrangement (built-up areas, access), road condition and the extent of signposting, including data on speed limits and overtaking as well as risk exposure variables. Due to the incomplete data on accidents and the small number of accidents, different approaches to the modelling of the number of road accidents were applied.
Modelling the critical concentration of mixed filler in mastic with synthetic wax
Authors: Mazurek Grzegorz , Iwański Marek
Published: January 2019

This article presents the results of tests of mastic containing mixed filler (limestone dust/hydrated lime) and Fisher-Tropsch synthetic wax. Synthetic wax content was controlled up to 3% (w/w). The ratio of filler in the bitumen was from 0.5 to 3 (w/w), with hydrated lime content of up to 30% w/w. The rheological properties of different mastic compositions were determined with a rheometer equipped with two parallel plates at 60°C using oscillating load. The primary purpose of the article was to determine the nature of mastic stiffness changes in the context of using hydrated lime and synthetic wax as the filler. Consequently, the article proposes a method for evaluation of the critical value of the filler phase in the phase of bitumen modified with synthetic wax. The proposed model of the mathematical function was used to determine the nature of mastic structuring throughout the range of the experiment. The model was also used to determine the critical concentration of the filler in the bitumen phase. It was demonstrated that below the critical filler concentration the mastic behaved in a significantly different manner from the behaviour observed above this critical concentration. When the critical concentration of the filler was exceeded, it resulted in an excessive increase of mastic stiffness, which was considered in the model.
Investigation of traffic conflicts at signalised intersections in Warsaw
Authors: Olszewski Piotr , Czajewski Witold , Osińska Beata , Szagała Piotr , Włodarek Paweł
Published: January 2019

Although traffic safety situation in general is improving, the numbers of pedestrians and cyclists hit when crossing a road have not significantly decreased recently. Based on police accident records for years 2010-2014, some 735 pedestrians and 505 cyclists were hit by motor vehicles in Warsaw. Investigation reported in this paper is a part of the European project InDeV. One aim of the project is to find correlation between accidents and traffic conflicts and thus provide a solid base for using surrogate safety measures as safety diagnostic tools. Three typical signalised intersections in Warsaw were selected for video recording. Relevant encounters between motor vehicles and vulnerable road users (pedestrians and cyclists) were identified and analysed using programs RUBA and T-Analyst. The paper describes the semiautomatic video data processing and problems regarding some technical and methodological aspects of conflict detection. Based on video analysis of 24 hours of recording for each intersection, preliminary characteristics of encounters between pedestrians/cyclists and motorised vehicles have been developed. Statistical distributions of encounter parameters such as time-to-collision (TTC) and post-encroachment time (PET) are presented. These will be used in the development of appropriate safety indicators.
Feasibility and strength properties of the geopolymeric binder made of fly ash suspension
Authors: Dawczyúski Szymon , Soczyúski Marek , GÓrski Marcin
Published: January 2019

Geopolymeric binders, or in general geopolymers, are nowadays applied in many different branches of the industry –also in building construction. This relatively new group of inorganic materials has similar strength properties as ordinary Portland cement (OPC) and in some features, it is even better (for example in terms of fire resistance or chemical resistance). It is also environmentally friendly material because industrial or mining tailings are used as its main components and the production process is not so energy consuming as in case of OPC. Paper presents laboratory research focusing on the curing temperature impact on strength properties of geopolymeric binder made of fly ash suspension. Besides the suspension which is a waste product from coal power plant, also recycled ground glass and metakaolin were used as the additions. The chemical activator of geopolimerisation reaction was prepared with the use of sodium hydroxide and sodium silicate. Prism samples 40x40x160 mm were done and then the flexural and compressive strength tests were performed. The paper also presents the impact of covering the moulds during heat curing on condition of geopolymeric binder samples.
Assessment of recycled concrete aggregate properties required for structural concretes
Authors: Węglorz Marek , Ajdukiewicz Andrzej , Kliszczewicz Alina
Published: January 2019

Assessment of recycled aggregate concrete (RAC) properties by laboratory tests is still required due to lack of precise guidelines and with taking into account slightly different behaviour of such concretes in comparison with natural aggregate concretes (NAC). It is especially important when recycled concrete aggregates are used for the structural elements. In this paper, the following rules for the whole concrete recycling cycle were defined: (1) rules for examination of original concretes selected for recycling and (2) rules for aggregate preparation and their fractionize as well as design rules for recycled aggregate concrete mixtures (including required tests of recycled aggregates and concrete properties). Requirements towards recycled aggregate concrete formulated in this paper are based on the long term experience and research works on the RAC which were held by A. Ajdukiewicz and A. Kliszczewicz in the Department of Structural Engineering of the Silesian University of Technology, practically since 1995.
From the Research on Risk Management in Polish Construction Enterprises
Authors: Myrczek Józef , Tworek Piotr
Published: January 2019

A variety of insurance options are used when managing risk in the construction industry. Numerous insurers operating on the Polish market provide suitable types of insurance, thus allowing participants of a construction process to obtain a comprehensive cover against almost all potential risks. Therefore, ‘all-risks’ types of insurance is of particular importance in case of construction and assembly activities. In addition to this instrument, the paper also deals with other forms of insurance used in the construction sector in Poland, which apply to various aspects of activities conducted by actors involved a construction project. This is the main topic of the paper, which also outlines the theory on the subject as well as providing the results of empirical research carried out in this area and emphasizing the practical applicability of the discussions. Consequently, the key aim of the paper is to present the issues related to insurance in the construction industry as a method of financing risk in operations of construction companies. The paper adopts a synthetic approach to these issues. The paper also reviews the related scholarly literature.
Probabilistic assessment of load-bearing capacity of deep beams designed by strut-and-tie method
Authors: Buda-Ożóg Lidia
Published: January 2019

This paper presents probabilistic assessment of load-bearing capacity and reliability for different STM of deep beams. Six deep beams having different reinforcement arrangement obtained on the basis of STM but the same overall geometry and loading pattern were analysed. The used strut-and-tie models for D-regions of analysed elements have been verified and optimised by different researchers. In order to assess load-bearing capacity of these elements probabilistically, stochastic modelling was performed. In the presented probabilistic analysis of deep beams designed, the ATENA software, the SARA software and the CAST (computer-aided strut-and-tie) design tool were used. The reliability analysis shown that STM optimization should be a multi-criteria issue so that the obtained models were characterized by optimal stiffness with the assumed volume or weight and maximum reliability.
Analytical model for determining the influence of support flexibility on shear capacity of hollow core slabs
Authors: Surma Mateusz , Derkowski Wit , Cholewicki Andrzej
Published: January 2019

The paper presents the authors’ model of calculating the shear capacity of prestressed concrete hollow core slabs in Slim Floor structures, the theoretical basis of which is Cholewicki’s two-beam model and the Finnish model by Pajari and Leskelӓ. The purpose of the model development was to find an alternative method for determining the horizontal tangential stress τzx which occurrence is decisive for reducing the shear resistance of channel slabs based on flexible supports. The model gives intermediate results between the Finnish model and the German model by Hegger and Roggendorf, which seems to be desirable, taking into account the conservative character of the Finnish model. The authors’ model is the first attempt to date at analytical consideration of the effect of web flexibility which may be important to maintaining an adequate capacity of the slab. In other models, the webs are treated as a rigid system, connecting the horizontal flanges of the slab. The model is a simple calculation tool, available to Slim Floor designers for an engineering analysis.
Analysis of the state of prestressed structure using data collection simulation technique
Authors: Woliński Szczepan , Pytlowany Tomasz
Published: January 2019

The paper presents a method of analysing the impact of basic variables on parameters characterizing the state of prestressed structures in transient and persistent design situation based on computer simulations and DOE (Design Of Experiments) data collection technique. The approach enables us to identify the key variables and to finde the limits of compromise area in which the state of structures are considered to be acceptably safe. Desing basis, procedures and results of the DOE technique use were presented on the example of a post-tensioned beam designed in accordance with the requirements of Eurocode 2. The study comprised the "what-if" analysis of the variation of total load, the losses of prestressing force in individual cables and the design depth of the beam section considering their influence on the ultimate load-bearing capacity and maximum deflection of the beam. The results obtained in the form of sensitivity and trade-off charts allow for the determination of the order and range of influence of the variables in the analysis, and the areas of unfavourable interactions of the studied variables on parameters characterizing safety of the structure.
Practical application of Eurocode provisions to design a steel frame of a building classified to the upper risk group
Authors: Barcewicz Wioleta , Al-Sahar Forat
Published: January 2019

Within the framework of this paper, the design of steel structure of the eight-storey building intended for a hotel is carried out, on the basis of Eurocodes. According to EN 1991-1-7, the building is classified to the upper risk group - CC2b and therefore additional requirements to the design has to be applied. The steel structure of the building should be checked in order to sustain an extent of localised failure from an unspecified cause without disproportionate collapse. It has been achieved by the three-part studies. In the first part, the frame structural members and the semi-rigid beam-to-column joints are verified for the normal design situation. The second part is related to the study of the structure subject to accidental damage due to a column loss. Three various accidental load cases are considered, in which the columns of the lowest storey are removed from three different positions. Finally, a design of the frame subject to the accidental situation has been performed using the key elements method based on the selection of the structural elements that are notified as the most critical and adoption of the recommended value of the accidental load, simulating an exceptional event within the accidental load combinations.
Equivalent stabilizing force of members parabolically compressed by longitudinally variable axial force
Authors: Biegus Antoni , Czepiżak Dariusz
Published: January 2019

The EN 1993-1-1 model of equivalent stabilizing force qd and Rd of bracings conservatively assumes that the braced member is compressed with a force constant along its length. This assumption is incorrect since the axial force distribution varies along the length of the braced member. As a result, the braced member generates equivalent stabilizing forces different from equivalent force qd and Rd acc. to EN 1993-1-1. This paper presents parametric studies of the equivalent stabilizing forces of the braced, compression top chord of roof trusses. The girder’s top chord is compressed parabolically by a variable axial force. The values of the axial compressive forces is: Nsupp in the support zone of truss and Nspan in the central zone of truss. Parametric analyses of the equivalent stabilizing force and the stress of the purlins and the bracings depending on axial forces Nsupp and Nspan in the braced member were carried out. The investigated problem is illustrated with exemplary calculations of the equivalent force in trusses.
Buckling resistance evaluation of steel beam-columns using refined General Method approach
Authors: Stachura Zbigniew , Gizejowski Marian A.
Published: January 2019

Different aspects of Eurocode 3 General Method (GM) approaches are discussed in this paper. The purpose of present study is to improve the application of GM approach for both beam-columns without intermediate lateral-torsional restraints and with these restraints. The results from the proposed GM are compared with those from Eurocode 3-1-1 interaction equations according to Method 1 and Method 2. A better consistency between the developed GM approach and the Eurocode's interaction equation approach than Eurocode 3 GM approach is observed.
On the validation of the LS-DYNA Geo Metro numerical model
Authors: Bruski Dawid , Burzyński Stanisław , Chróścielewski Jacek , Pachocki Łukasz , Witkowski Wojciech
Published: January 2019

The paper presents experiences gained during work with numerical model of Geo Metro vehicle used for simulations of crash tests with road safety barriers. Attention is drawn to the subject of tire/wheel breakage during collision events. Some methods for improvement of the model are presented in the paper. Several results for the normative vehicle numerical tests are introduced. Simulations were carried out using LS-DYNA finite element code with solver version R8.1.
Detection of debonding in adhesive joints using Lamb wave propagation
Authors: Rucka Magdalena , Wojtczak Erwin , Lachowicz Jacek
Published: January 2019

Adhesively bonded joints are widely used in many branches of industry. Mechanical degradation of this type of connections does not have significant symptoms that can be noticed during visual assessment, so non-destructive testing becomes a very important issue. The paper deals with experimental investigations of adhesively bonded steel plates with different defects. Five samples (an intact one and four with damages in the form of partial debonding) were prepared. The inspection was conducted with the use of guided wave propagation method. Lamb waves were excited at one point of the sample, whereas the out-of-plane velocity signals were recorded in a number of points spread over the area of overlap. The processing of signals consisted of calculations of weighted root mean square (WRMS). The results of the analysis showed that the WRMS maps allow for identification and determination of size and shape of debonding areas.
Analysis of static forces generated in-track on a railway sleeper resting on an elastic foundation due to structural imperfections using the PONTOS system
Authors: Bednarek Włodzimierz Andrzej
Published: January 2019

In the paper a considered railway sleeper was analysed as an Euler-Bernoulli beam and a Timoshenko beam of finite length resting on a oneand two-parameter foundation. The foundation parameters were determined based on a modified and analogue Vlasov soil model and field investigations. The main concept for the executed investigations was to induce an intentional imperfection in an actual railway track, propose a way of appropriate measurement (e.g. the PONTOS system by GOM mbh), and utilize author’s field investigations results to calibrate necessary parameters for theoretical calculations. An experimental formula describing the value of the force transferred from the rail to the railway sleeper on the grounds of the survey site caused by a locomotive was given. Furthermore, the deflection of the chosen railway sleeper due to the generated imperfection was analysed. Finally the objective of the present analysis was to resolve the calculations into the beam element such that the results can be utilised in computational railway practice. In the presented paper also the computational examples, diagrams and tables reflecting influence of analyzed parameters on obtained a CWR track’s displacements are enclosed.
Construction of ropeways in Slovakia in terms of pre-construction design using helicopters (case study)
Authors: Bisták Andrej , Hulínová Zdenka
Published: January 2019

Ropeways usually provide access to locations inaccessible to other means of transport. Due to this fact, the construction of ropeways is extraordinarily taxing in terms of both, technology and logistics. The site location is often in terrain difficult to access, which often precludes deployment of common construction mechanisms in ropeway construction. In such case, it is advisable to deploy a transport mechanism independent of the terrain – a helicopter. Functioning as “flying cranes“, the helicopters have been used in construction industry in Slovakia for six decades now. Having amassed positive experience, even the “conventional“ construction industry of the time, especially its ropeway transport segment, started to use the benefits of helicopters, with helicopter deployment subsequently gaining ground and becoming the mainstream technological procedure. Ropeway construction can hardly be feasible without them even nowadays. Throughout the history of helicopter deployment in construction industry, a constant search of improving the efficiency of their work has been under way, necessitated by the helicopter’s sensitivitiy to weather conditions and work procedures alike. The paper presents an analysis of the factors affecting helicopter operation together with a proposed methodology of modeling their work in simulation models and the benefits of such approach.
A simulation model of material particle trajectory by shifting of material by free fall
Authors: Molnár Vieroslav , Šveda Mikuláš
Published: January 2019

The paper is aimed at the calculation of the throwing parabola of material particle and its graphical interpretation by changing input parameters selected according to predefined requirements. The aim is to compile a complex simulation model and comparison of the obtained simulation results on the model with analytical calculation. Simulation experiments on the model confirmed the known dependence of the change of throwing parabola by increased speed and retention of the radius of the staging drum. The simulation model was created in the program MSC Adams/View – a tool for easy construction and visualization of the model and convenient evaluation of the obtained results.
Assessment of the transverse roughness of the thin-walled cooler for the robot control system made using CAM programming
Authors: Tirpak Peter , Michalik Peter , Hatala Michal , Petruš Michal
Published: January 2019

The article deals with design and design of a thin-walled heat sink for the robot control system, the measurement of the transverse roughness of the touch surfaces and the programming procedure in Autodesk Inventor 2019 software. In this software, a design of the 3D model of the heat sink generated based on power supply and NC code generation for the Fanuc control system. The production it-self carried out on the CNC Vertical Machining Center Pinnacle 2100 with this control system. The longitudinal surface roughness was measured with a Mi-tutoyo SJ 400 dredger and the measurement result was the maximum Ra = 0.69 μm and Rz = 4.1 μμm.
Flaking of PEEK under one-point rolling contact fatigue using Al2O3 ball
Authors: KOIKE Hitonobu , YAMAGUCHI Genya , MIZOBE Koshiro , KIDA Katsuyuki
Published: January 2019

The growth of flaking as tribological fatigue failure in PEEK was investigated through the one-point type rolling contact fatigue test between a machined PEEK polymer shaft and an alumina bearing's ball. Due to Hertzian contact of cyclic compressive stress, the subsurface fatigue cracks in the PEEK shaft propagated in rolling and axial directions. When the rolling fatigue life of the PEEK shaft reached 106 fatigue cycles, many narrow angled cracks occurred in the near-surface of the rolling track without flaking. On the other hand, when the flaking ocuurred on the PEEK shaft before 106 fatigue cycles, semicircular surface and subsurface crack propagations were observed. From these observations, it was found that micro-flaking occurred due to the linkages between subsurface and surface cracks. Flakingdeveloped due to the accumulation of these micro-flakings.
Influence of groove shape on rolling contact fatigue of PEEK-PTFE hybrid radial bearings in dry conditions
Authors: Inagaki Masahiro , Mizobe Koshiro , Kida Katsuyuki , Kashima Yuji
Published: January 2019

In this study, rolling contact fatigue (RCF) tests were performed in order to investigate the effect of groove radius on the life of PEEK-PTFE hybrid radial bearings. Furthermore, solid state NMR spectroscopy was performed in order to investigate the molecular structure of PEEK. It was found that groove radius shape was related to limitations of the bearings, and the molecular structure of the PEEK was not changed by the temperature rise in this test. Furthermore, thermal failure of the PEEK was not affected by oxidation during RCF test.
Study on Thermal Properties and Mechanical Properties of Short-cut Polyimide-Fiber Reinforced Polyphenyl Sulfone Composites
Authors: Yao Weizhou , Yao Jianan , Jiao Qing , Wei Yunhai , Yu Tianpeng , Yu Youhai , Li Hui
Published: January 2019

In order to increase the thermal stability and mechanical property of PPSU, two different polyimide (PI) short cut fibers reinforced polyphenyl sulfone (PPSU) composites were prepared by melt extrusion using a threescrew extruder. In addition, the effects of fiber lengths on thermal stability, heat resistance and mechanical properties of the composites was studied. The results indicate that the addition of polyimide chopped fiber can greatly improve the heat resistance of the composites. Comparing with PPSU, with the increasing of fiber content, the heat deformation temperature (HDT) of composites increased from 205 °C to 229 °C, but the addition of polyimide fiber has limited effect on the thermal stability of the composites. Meanwhile, the addition of polyimide chopped fiber can also improve the mechanical properties of the composites. Compared with PPSU, the tensile strength of composites can be increased by 102%, and the bending strength can be raised by 117%.
Experimental study on fiber mortar strength at early age under temperature difference
Authors: Zhang Yan , Li Ning
Published: January 2019

The condition of high temperature is easy to destroy the concrete structure of tunnels. Many temperature difference conditions are applied to ordinary mortar and fiber mortar specimens, the early strength values of mortar caused by temperature change were measured. The flexural strength change rules of the specimens were analysed. The influence of temperature difference on different specimens, and the cause of the strength difference and failure of the specimens are studied. It provides experimental basis for improving the service life of high temperature tunnel cement concrete structure.
High-strength concrete with new organic mineral complex admixture
Authors: Abu-Khasan Makhmud , Soloviova Valentina , Soloviov Dmitry
Published: January 2019

There are the great problems of the concrete for high voltage the transmission lines obtaining. One of them is the creation of reinforced concrete centrifugally spun transmission towers with enhanced reliability and durability for high-voltage transmission lines having voltage of 110-750 kV. The second problem is the creation of high-quality reinforced concrete foundations to fix overhead electric line lattice towers in the ground because more than 50% of operated reinforced concrete towers and foundations are in need of repair or were put into repair. A complex high-performance organic mineral admixture for tower bodies of high-voltage transmission lines is developed. The main components of the admixture are polycarboxylate polymere and silica sol. It insures increased compressive strength and tensile strength in bending, freeze resistance, waterproofing and corrosive resistance. The obtained positive results allow to reduce a compression zone width and a crack growth width. The paper can be useful for not only the transport construction but and for concrete obtaining with special properties at any fields.
Instruments of granular matrix mechanics for solving design-level tasks on shear strength resistance of loosely-coupled material in cast stone pavement
Authors: Moshenzhal Andrey , Zhdanova Svetlana , Piotrovich Aleksey
Published: January 2019

The paper covers the method of distribution analysis for normal and shear stresses in a multilayer cast stone pavement design. The method is used to test the shear strength requirements. Some conclusions about the expediency of considering the granular matrix discrete structure applied in transport construction are made.
The influence of lithium carbonate on the heat release during the hydration of Portland cement at the temperature 40°C
Authors: Kuzina Anisa , Shokodko Ekaterina , Pustovgar Andrey , Adamtsevich Aleksey
Published: January 2019

This work represents the stage of the author's research aimed at identifying the solutions for increasing the energy efficiency of the production of precast concrete and reinforced concrete products and structures in plant conditions due to reducing the temperature of heat treatment, or due to the reduction of duration of this technological process. The work provides results of the research of the influence of the admixture of lithium carbonate (Li2CO3) on the dynamics of hydration process of the binding systems on a cement basis in the conditions of the increased temperature (40°C). The research was performed using the method of isothermal calorimetry on the two various samples of the cement binder, conducted in various countries. The Li2CO3 admixture is accepted in dosages from 0.5% to 2.5%. The graphical dependence of the heat flow of the exothermic reaction of hydration on the used lithium carbonate dosage in the first days of curing of the samples is established and presented.
Impact strength of underground cement materials
Authors: Travush Vladimir I. , Karpenko Nikolay I. , Erofeev Vladimir T. , Cherkasov Vasiliy D. , Emelyanov Denis V. , Erofeeva Irina V.
Published: January 2019

The article presents the results of a study of impact strength of underground cement materials with different water content activated by mixing water with the addition of high range plasticizers, biocidal agents, pigments, ground quartz, silica fume and fine aggregate. Samples for testing are formed in plates of size 150×100×10 mm. Testing was conducted at impact drop-weight method ASTM D7136. The maximum contact force, contact duration and magnitude of the pulse of the drummer were considered as the test parameters. The good results of the studied parameters showed highly filled plasticized compositions of the new generation. The use of iron oxide with yellow and green glauconitic pigments allows obtaining good results. Activation of the mixing water led to a rise in the maximum contact force in the case of the processing mode of E+М (3–3) while reducing the duration of the contact and the magnitude of the impulse. During the test of the biocidal composites with different biocidal preparations, it was established that the best indicators of the impact strength correspond to materials with the addition of «Teflex Antiplesen».
Application of geosynthetic materials for road structures
Authors: Akhmetshin Elvir , Kovalenko Kseniya
Published: January 2019

In this article, the authors examines the application of geomaterials in road constructions, it economic indicators, the dependence of surface density and unit cost, as well as strength and unit cost, are analyzed. The economic and technical advantages of using woven geomaterials are shown. Geosynthetic materials allow increasing the strength of road structures and reducing the cost of construction while maintaining strength and reliability. Geogrid road has all the permits and technical documentation: the calculation methods are developed for the solution of road construction. Woven geomaterials are the best to use and have a number of advantages, but now nonwoven geomaterials are usually used in Russia, which is caused by imperfect design methods that do not take into account the strength of the geomaterial and reduce the density of pavement when using thick geomaterials. Geomaterials are geosynthetic products for strengthening slopes, slopes, coastal zones, road surfaces and other territories that need strengthening of soils. Geomaterials, among other things, are an excellent protection against erosion, environmentally safe, reliable, have a long useful life and are easily installed. Depending on the needs and type of territory, geogrids, geomatics and road geosets are used.
Experimental study of repair mixtures as glues for connecting elastomers with metals
Authors: Ishchenko Anatoliy , Artiukh Viktor , Mazur Vladlen , Poberezhskii Sergey , Aleksandrovskiy Maxim
Published: January 2019

Experimental study of strength of glued connections where repair mixtures Diagum FL, Diagum Р and Diaflex are used is shown. Suggestions of each repair mixture use are given. Obtained results provide developing of durable and economical technical solutions: shear shock absorbers, elastic couplings, elastic shafts with high energy intensity which in some cases allow to avoid failures of metallurgical equipment under dynamic loading. In addition, use of repair mixtures with elastomers helps to make durable coatings of steel surfaces.
Analysis of micro-holes shape in a textile terminal using optical microscopy
Authors: Agafonova Vera
Published: January 2019

Currently, development and improvement of ventilation and air conditioning systems efficiency is related with the use of new devices for air transportation and distribution. These include micro perforated air distributors made of textile which are installed both at the level of the indoor working area and directly near the workplace. Air terminals of this type are made of polymer composite material – fabric based on synthetic fibers. To make such a fabric, modern laser technology to produce micro-holes is used which allows burning in the fabric holes of a given diameter and pitch with melted edges. Results of studies on shape and size of micro-holes in the micro perforated textile terminal are described in this paper. A conclusion is made that the micro–holes shape is irregular and the holes boundaries have uneven edges. Data on micro-holes area range are given. Actual diameter of the micro-holes declared by manufacturer is defined more exactly.
Variation of traffic flow due to accumulated snow formation on road
Authors: Munehiro Kazunori , Nakamura Naohisa , Sato Masaya
Published: January 2019

Sapporo City has one of the heaviest snowfalls worldwide, and the road conditions in winter are getting remarkably worse. Snow removal works in winter are indispensable in order to secure traffic functions in the city. Snow accumulates on roads as soon as it is removed. It is also a problem that the deposited snow protrudes into the lanes of roads and the traffic flow drops. This study analyzed the size of deposited snow formation and the variation of traffic flow. We set up a camera for a four-lane road managed by Sapporo City (two lanes per side) and observed two seasons continuously. Width of deposited snow and traffic performance (Traffic Volume - Velocity) were analyzed based on the acquired images. The width of deposited snow was from 1.0 m to 2.5 m. When the width of the deposited snow exceeded approx.1.5 m, it was indicated that only one lane of the road will be in operation if it is originally operated as two lanes per side, with about 70% of the traffic volume and about 80% of the speed. In addition, based on the actual situation of use of bicycles and pedestrians in autumn, we propose redistribution of road cross-sections considering snow coverage width.
The use of foresight in technical systems
Authors: Nikitin Sergey , Novikov Arthur , Novikova Tatyana
Published: January 2019

The study is intended for engineers designing technical systems. The analytic hierarchy process was used as the main tool of foresight. Nowadays, some experience in the design of technical systems is accumulated. However, in most cases, designers have to sort through all possible factors and parameters of devices. The involvement of experts will reduce the time range of research. The research results show a high Kendall’s coefficient of concordance 0.738. Research materials will allow planning experiments only with the most important factors. This will adjust the protocols for testing new technical systems and significantly reduce costs.
Application of electric resistivity tomography for investigation of geological situation closed to railways
Authors: Gorbach Dmitriy , Yakimenko Valeriya , Konovalova Olga
Published: January 2019

The paper reviews methods of engineering geophysics which can be applied to sections of railway tracks. The method of electrical resistivity tomography is used to study the properties of the geological situation under an engineering structure. In the course of practical work, two-dimensional geoelectric sections were obtained. Interpretation of the sections allowed to understand the structure of the near-surface zone.
Scientific evidence of the solution to the problem of compacting man-made sandy sub-structures in winter conditions
Authors: Minaev Oleg
Published: January 2019

In the recent time the issue of erecting soil sub-structures and constructions at negative temperatures in winter conditions and the areas of permafrost has been really important, so such research studies are very topical. The paper provides for the results of experimental compacting of medium sands of a sub-structure in winter conditions (at the ambient temperature of – 200… 250C) in the construction of a complex of protective structures (CPS) preventing floods in St. Petersburg. Heavy and medium-heavy vibratory compactors were used in the experimental sections. Before compaction, sandy soils of the sub-structure with the layer thickness equal to 0.4…0.5 m were placed. For comparison purposes, the paper contains the results of layer-by-layer compaction of such sands in the summer season with application of vibratory compactors and deep-water vibratory plant in the subs-structure of the freeway along the ridge of the protective dam from the side of the Gulf of Finland in the construction of the CPS.
Temperature monitoring of surface layers of the earth in Perm
Authors: Ponomaryov Andrey , Zakharov Aleksandr
Published: January 2019

The article presents the results of monitoring the temperature of the surface layers of the earth. Monitoring was carried out at two sites with engineering-geological conditions typical for Perm. The geological conditions of the first site are clay soils, the second site is sandy. The first site is located in a dense urban development, the second in an unfinished part of the city of Perm. The depth of the soil massif on which the temperature was monitored was: for the first site - 19 m, for the second site - 37 m. Based on monitoring results, a picture of the temperature change in the soil massif in time for both sites was obtained. In the article, the average monthly temperatures of the soil massif are plotted on both sites. The zone of fluctuations in the temperature of the soil massif is revealed depending on the temperature of the outside air. The depth of the zone of seasonal temperature fluctuations was 10m. Monitoring determined that the temperature of the ground mass is below 10m: for the first site + 12 ° C with a decrease in temperature to 10°C to a depth of 19m, for the second site - a constant + 6-7°C to a depth of 37m.
Structure soil stabilization with natural materials in the Russian Far East
Authors: Zhdanova Svetlana , Piotrovich Aleksey , Moshenzhal Andrey
Published: January 2019

The paper covers some results of scientific and practical use of different design-technological solutions developed by the Far East State Transport University on the basis of the local materials such as rock and clay soils or strengthening compositions from the rock refuse of local mineral resources. The latter are developed and introduced into practice by the authors for dewatering and stabilization of the swamp material in the roadbed and other earth structures. The lab research of the soils and examples of their uses are presented in diagrams. The paper covers the conclusions about feasibility and effectiveness of local material
Research of a new method of sealing of sandy soil foundations
Authors: Minaev Oleg , Kolosov Michail
Published: January 2019

The paper presents the results of the author's research aimed at finding new methods of vibrodynamic sealing of sandy soils foundation by using the energy of water flow. The data of water flow parameters providing the given speed of its movement without the significant carryover of sand particles based on the theoretical studies, as well as the laboratory studies of sandy soil dumping into a water flow (with an average horizontal velocity of about 10-15 cm/s) on a specially designed hydraulic tray are described in the paper.