bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyzing the Cooling Efficiency of the Thermal Environment in Data Centers
Authors: Xu Yongmei , Zhang Jingru , Deng Yuhui , Du Lan , Jiao Rong
Published: April 2015

Given the explosive growth of data, scalability and fault tolerance have become a fundamental challenge for data center network structures. Temperature in data centers significantly affects the failure ratio of high-speed network devices. Various types of air distribution schemes influence the temperature of network equipment differently, and the cooling cost in data centers dominates the overall energy cost. On the basis of the energy efficiency of cooling systems, this study analyzes and compares the thermal load distribution in the enclosure of standard and non-standard data centers by considering the effects of the external environment. Analysis results demonstrate that the external environment significantly affects the thermal load of non-standard data centers. By leveraging on the air temperature outside data centers and on the inlet/outlet of IT equipment, the air temperature and return air temperature of air conditioning are calculated when performing hot and cold aisle containment. The calculations indicate that sealing an appropriate aisle (hot or cold aisle) can significantly reduce the energy consumption of cooling systems in terms of the external air temperature outside data centers. Furthermore, if the air temperature outside data centers is higher than the temperature at the inlet of IT equipment, sealing the cold aisle outperforms sealing the hot aisle. By contrast, the aisle to be sealed depends on the energy efficiency ratio of the air conditioning.
Ambulance Dispatching System with Integrated Information and Communication Technologies on Cloud Environment
Authors: Li Jian-Wei , Chang Chia-Chi , Chang Yi-Chun , Huang Yung-Fa
Published: April 2015

The quality of emergency medical services (EMS) prior to a patient's arrival at a hospital is directly affected by the efficiency to dispatch an ambulance for first aid. In this paper, we created an ambulance dispatching system for first aid, which is integrated with Information and Communication Technology (ICT) and performed on a cloud platform. In virtue of ICT, the system can readily monitor the movements of ambulance with Geographic Information System (GIS) and determine any ambulance dispatching task and saves more time spent in transporting an accident victim to a hospital. Furthermore, the system running on a cloud platform is characteristic of integrated medical resources and terminal equipment with or without powerful hardware that is flexibly added into or removed from the system for supporting dispatch.
Tweet Sentiment Analysis with Latent Dirichlet Allocation
Authors: Ohmura Masahiro , Kakusho Koh , Okadome Takeshi
Published: April 2015

The method proposed here analyzes the social sentiments from collected tweets that have at least 1 of 800 sentimental or emotional adjectives. By dealing with tweets posted in a half a day as an input document, the method uses Latent Dirichlet Allocation (LDA) to extract social sentiments, some of which coincide with our daily sentiments. The extracted sentiments, however, indicate lowered sensitivity to changes in time, which suggests that they are not suitable for predicting daily social or economic events. Using LDA for the representative 72 adjectives to which each of the 800 adjectives maps while preserving word frequencies permits us to obtain social sentiments that show improved sensitivity to changes in time. A regression model with autocorrelated errors in which the inputs are social sentiments obtained by analyzing the contracted adjectives predicts Dow Jones Industrial Average (DJIA) more precisely than autoregressive moving-average models.
Analytical and Experimental Study of Electrochemical Micromilling
Authors: Kamaraj Abishek B. , Sundaram Murali M.
Published: April 2015

Electrochemical micromachining (ECMM) is a non-conventional manufacturing method suitable for the production of microsized components on a wide range of conductive materials. ECMM improves dimensional accuracy and simplifies tool design for machining hard, high strength, heat resistant, and conductive materials into complex shapes. Extremely small interelectrode gaps of the order of few microns are required in ECMM for better dimensional accuracy. However, excessively small interelectrode gaps may lead to complications, such as short-circuiting, which disrupt the stability of ECMM process. This necessitates the need for better understanding of the interelectrode gap dynamics. This paper presents a mathematical model for the analysis of interelectrode gap under non-steady state conditions in micromilling of steel using the ECMM process. Experimental verification of the mathematical model was conducted using an in-house built micro electrochemical machining system. The model is capable of predicting the machining results to within 1- 5 µm error (10- 50%).
Technological Innovations in Machining of Inconel 718
Authors: Aggarwal Vivek , Garg Rajiv K , Khangura Sehijpal Singh
Published: April 2015

In this paper, a thorough review has been presented on the latest research work carried out for the enhancement of machining performance of one of the most commonly used superalloys that is, Inconel 718. The thermal energy has been frequently utilized for improving machinability characteristics of Inconel 718. The review of available literature indicates that plasma, laser, and electric discharge have been the major sources used for the enhancement of tool life, material removal rate, surface integrity, and reduction of cutting forces during machining of Inconel 718. However, a very few efforts have been made as regards to the use of wire electrical discharge machining and other energies like mechanical, electrochemical, and chemical for machining of this material. Moreover, the reported work on machining of Inconel 718 is largely focused on drilling operations. There is ample scope for research work on various other machining operations using alternative energies to gain more insight into machining of Inconel 718 and other similar superalloys.
Assessment of Direct Laser Writing using Nd YAG Lasers for Microfluidic Applications
Authors: Mohammed Muneer Khan , Al-Ahmari Abdulrahman , Umer Usama
Published: April 2015

The rapid growth in the use of Micro/Nano products in variety of industries such as Micro electromechanical systems (MEMS), microelectronics, Biomedical/Bio-MEMS, automotive (motion sensors), telecommunications etc, has demanded new micro manufacturing methods. The challenge with the manufacturing of Microfluidic devices/biochips is that they often make use of broad range of materials within a single chip, making it difficult to manufacture these devices with conventional photolithographic based techniques. Laser processing of materials has proved to be an important tool for the development of these devices because of the accuracy, flexibility and the most important one material independence it offers. This research focus on optimization of laser process parameters for the machining of Microfluidic channels with AISI 1045 steel. Design of experiments (DOE) technique was used in order to study the effect of laser process parameters on rectangular and semicircular cross-section channels.
Theory, Analysis and Measurements of Rectangular Patch Resonator Sensors
Authors: Aouabdia N. , Belhadj-Tahar N. E. , Alquie G.
Published: April 2015

This paper has for objective to explore the study of a sensor based on a rectangular planar resonator (RPR) for applications to Non-destructive Evaluation (NDE). In this context, conception, modeling, simulation and realization have been made on rectangular structures with an anisotropic substrate and an isotropic superstrate. The theoretical model is based on the moment method (MoM) via Galerkin's approach, in which three types of basis and testing functions are used. These functions as well as the spectral dyadic Green function are efficiently implanted on compact structured Fortran 90 codes. The accuracy of the obtained results is assessed using four prototypes of RPRs operating around 6 GHz, taking only into account the Resonant Frequency (RF) of the fundamental dominant mode. The theoretical model is compared to simulation and measurements results and shown very good agreements. The RPR criteria are established theoretically and validated experimentally with two electromagnetic commercial softwares (HFSS and CST); to be used in future prospects as an electromagnetic (EM) sensor for the characterization of superstrates.
New Ultrasound-Based Methods for Early Osteoporosis Diagnosis and Fracture Risk Estimation
Authors: Casciaro Sergio , Renna Maria Daniela , Pisani Paola , Greco Antonio , Conversano Francesco , Muratore Maurizio
Published: April 2015

Osteoporosis is the most common disorder of bone metabolism. The main consequence of this disease is the increased risk of fracture. Osteoporotic fractures represent a serious problem in terms of social and economic costs. Then, there is a strong need for the assessment of the best practices in prevention and treatment of osteoporosis. Dual X-ray absorptiometry (DXA) represents the current “gold standard” method for osteoporosis diagnosis. However, DXA cannot be employed for population mass screenings, because of required exposition to ionizing radiation and high management costs. The aim of this paper was to review the currently available techniques for osteoporosis diagnosis and also to illustrate the feasibility of an innovative quick, cheap and non-invasive ultrasound-based methodology. The results recently published by the authors' research group suggest that the proposed approach has the potential for routine application in early diagnosis, which is the key to resize the impact of osteoporosis on healthcare systems.
Development of Near-Diffraction Limited, Low-Cost and High-Resolution CCD Camera System for Imaging Coulter Orifices
Authors: Alaruri Sami D.
Published: April 2015

A low-cost CCD camera system for imaging Coulter orifices ranging in diameter between 20 µm and 2 mm has been developed and tested. The imaging system incorporates a 6X magnifying lens for viewing the required range of Coulter orifices and LEDs (Light emitting diodes) lamp for back illuminating the orifices. Geometric optic calculations using Zemax® for the micro-lens interfaced with the camera suggest that the spot diameter and the MTF spatial frequency at field of view equal to 0 ° and at the image plane are 5.13 µm and 271.6 lines/mm (at contrast= 37.6%), respectively. Images captured with the camera system for 20 µm, 100 µm and 2 mm diameter orifices are provided. Furthermore, a discussion for the camera micro-lens modulation transfer function, spot diagram, root-mean-square wavefront error versus field and optical path difference plots is given.
Design of a Web-Based Sentence Analysis System to Support EFL Reading Instruction
Authors: Tsai Yea-Ru , Chang Yukon
Published: April 2015

The purpose of this study was to investigate the effects of an on-line Cumulative Sentence Analysis (CSA) instruction on university engineering students' English reading comprehension. Within the framework of CSA instruction, the reading comprehension process can be divided into six steps: identifying finite verbs, finding key words, separating clauses, identifying subjects and main verbs, adding words stepwise, and translating the sentence. The results showed that the experimental group achieved a higher level of reading comprehension performance following the instruction. Inter-group comparison also revealed that the experimental group significantly outperformed the control group in the post-test, while no difference was found between these groups in the pretest. The findings clearly demonstrated that on-line CSA instruction is an efficient and feasible approach to helping engineering students cope with their problems of reading English texts.
A Procedure to Engage Children in the Morphological and Syntax Analysis of Pedagogic Conversational Agent-Generated Sentences to Study Language
Authors: Marín Diana Pérez
Published: April 2015

Pedagogic Conversational Agents are computer applications that interact with the students in natural language. They usually focus the dialogue on a certain topic under study. In this paper, the authors propose the possibility of children studying morphology and syntax by using a Pedagogic Conversational Agent. The main benefit is that the agent is able to generate an infinite number of sentences and, it automatically generates the morphological and syntactical analysis from a given grammar. That way, students can practise with all the sentences they need, receive immediate feedback with automatic evaluation, at their own rhythm and, the level of difficulty can be adapted to their particular competence of analysis. Given the originality of this new computer assisted learning initiative, the authors have devised a procedure to engage the students in the dialogue with the agent to carry out the morphological and syntax analysis at five different levels of difficulty, and test the validity of the approach with a limited number of users according to the principles of User-Centered Design. The results gathered provide evidence of the goodness of the procedure and, they encourage us to keep working on this promising field of using pedagogic agents as computer teaching language assistants.
The Learning Satisfaction, Attitudes, and Grades of E-Tutees Receiving Online English Tutoring
Authors: Huang Chiung Wei , Liu Eric Zhi Feng
Published: April 2015

One-on-one online English tutoring provides equal educational opportunities for students living in remote areas. This study examines the learning satisfaction, attitudes, and grades of e-tutees receiving online English tutoring. Ten e-tutees and ten e-tutors participated in the study. The study found that the e-tutees were satisfied with their one-on-one online English tutoring and that they performed well on online English tests. In addition, evaluations made by e-tutors show their e-tutees learning attitudes were positive. Online English distance education not only overcomes the limitations of space and time but also facilitates e-tutees' learning and development.
Design and Implementation of a Cognitive Tool to Detect Malicious Images Using the Smart Phone
Authors: Nishiyama Hiroyuki , Mizoguchi Fumio
Published: April 2015

In this study, the authors design a cognitive tool to detect malicious images using a smart phone. This tool can learn shot images taken with the camera of a smart phone and automatically classify the new image as a malicious image in the smart phone. To develop the learning and classifier tool, the authors implement an image analysis function and a learning and classifier function using a support vector machine (SVM) with the smart phone. With this tool, the user can collect image data with the camera of a smart phone, create learning data, and classify the new image data according to the learning data in the smart phone. In this study, the authors apply this tool to a user interface of a cosmetics recommendation service system and demonstrate its effectiveness by in reducing the load of the diagnosis server in this service and improving the user service.
Enhanced Global Best Particle Swarm Classification
Authors: Nouaouria Nabila , Boukadoum Mounir , Proulx Robert
Published: April 2015

Particle Swarm Classification (PSC) is a derivative of Particle Swarm Optimization (PSO) based on the retrieval of the best particle positions corresponding to the centroids of classes. This paper addresses how the position update mechanisms impacts the accuracy of a global best PSC approach. The authors present two variants of the PSC algorithm with different position update mechanisms. In particular, the authors show how the combination of a good parameters tuning, a particle confinement to the search space and a biologically inspired wind dispersion mechanism for them improves the covering quality of search space and thus the classification accuracy of the basic global PSC algorithm. An experimental set up was realized and tested on five benchmark databases, leading to better recognition accuracies than those obtained with the previous PSC algorithm.
Evaluation of FLOSS by Analyzing Its Software Evolution
Authors: Macho Héctor J. , Robles Gregorio , González-Barahona Jesus M.
Published: April 2015

In today's world, management often rely on FLOSS (Free/Libre/Open Source Software) systems to run their organizations. However, the nature of FLOSS is different from the software they have been using in the last decades. Its development model is distributed, and its authors are diverse as many volunteers and companies may collaborate in the project. In this paper, the authors want to shed some light on how to evaluate a FLOSS system by looking at the Moodle platform, which is currently the most used learning management system among educational institutions worldwide. In contrast with other evaluation models that have been proposed so far, the one presented here is based on retrieving historical information that can be obtained publicly from the Internet, allowing the authors to study its evolution. As a result, they will show how using their methodology management can take informed decisions that lower the risk that organizations face when investing in a FLOSS system.
Inquiring into Structure of Hyperbranched Polyethylene Produced in Radical Polymerization Process
Authors: Koval Evgeniy , Echevskaya Ludmila , Matsko Mikhail , Pestryakov Alexey , Mayer Edward
Published: April 2015

This paper presents the analysis of rubberlike hyperbranched polyethylene (PE) deposits in separators and high-pressure (HP) recycle system with use of NMR spectroscopy 13С, X-ray phase analysis and differential scanning calorimetry; polymer extraction separation with boiling o-xylene and comparison of fraction characteristics have been carried out. With literature data and process conditions taken into account the potential reason of such structure polymer synthesis is being under discussion.
Electric Drill Drive with Intermediate Rolling Members Reducer
Authors: Korotkov V.S. , Razumov S.V.
Published: April 2015

The article considers briefly the hand power tool market in Russia. The authors set the parameters of a wave gear electric drill with intermediate rolling solids. Its field of application is also described. The design is developed on the basis of a commutator motor with a useful capacity 1,0 kW. The rotation speed ​​of the motor armature is 15000 rpm. The rational rotation frequency of an auger working body is 200...300rpm. It is necessary to create a gear with a ratio 59 and with parameters comparable to the size of a hand-held machine engine in order to have esthetics. In this case, the diameter of rolling elements should lie in the range 2 to 3 mm. The authors made a research on hand-held electric drill runnability with such characteristics. They presented dependency diagrams of an auger working body critical rotation frequency from a lead angle while drilling different types of soil. They determined important power and geometrical criteria to design a gearbox. The calculation results are presented in tables.
Development of Composition and Research of Rheological Properties of Thermoplastic Slips on the Basis of Aluminium Nitride
Authors: Ditts Alexander A. , Revva Inna B. , Pogrebenkov Valeriy , Pautova Yulia , Nazarova Anastasiya , Galashov Evgeniy , Tarnovskiy Roman
Published: April 2015

Thermoplastic slip from commercial powders of yttrium nitride and yttrium oxide. The scheme of making the slip is proposed, the casting properties are determined. The influence of sintering additives dispersion and molding conditions (pressure, temperature) on slip properties is researched.
Volume Self–Sustained Discharge in Atmospheric Pressure Gas with High Pulse Repetition Frequency
Authors: Zhuravlev M.V. , Remnev G.E. , Shubin B.G.
Published: April 2015

The paper describes a plasma source based on a self-sustained volume discharge for diamond and diamond-like film deposition. The suggested scheme of the electrode system enables to provide stable combustion of the self-sustained volume discharge with high pulse repetition rate in atmospheric pressure gases. Gas flow rate to blow off the interelectrode gap depending on the anode temperature has been considered.
Force Analysis of Double Pitch Point Cycloid Drive with Intermediate Rolling Elements and Free Retainer
Authors: Efremenkov E.A. , Kobza E.E. , Efremenkova S.K.
Published: April 2015

This paper illustrates the analysis of wedge angle influence on force distribution in the meshing of double pitch point cycloid drive in comparison with single pitch point cycloid drive. Double pitch point cycloid drive may provide smoother performance of transmission at starting period in consequence of wedge angle variation capabilities. Matching initial parameters it is possible to modify the wedge angle and achieve its effective value. The influence of various combinations of initial parameters on the wedge angle and retainer force was studied and presented on diagrams. Some recommendations in designing related to performance improvement are given. The obtained results can be used for further development of better designs of cycloid drives.
Oxide Powder Plasma Processing by Low-Energy Ions of Titanium
Authors: Vodopyanov E.M. , Loginova Anna V. , Ivashutenko Aleksander S. , Martyushev N.V.
Published: April 2015

This work presents the characteristic properties of powdered materials sintering under conditions of liquid-phase sintering. It has been established that to implement the liquid-phase sintering advantages it is necessary to do temperature research when the liquid-phase concentration does not exceed the critical one. The implementation of this condition provides the sintering temperature reduction by 150 – 200 °С.
Investigation of Ultradispersed Powders FexOy Obtained in the Electric Discharge Plasma
Authors: Sivkov Alexander A. , Ivashutenko Aleksander S. , Lomakina A.A. , Shanenkov I.I.
Published: April 2015

The paper shows the iron oxide powder production in the hypersonic jet of electro discharge plasma generated by a coaxial magnetoplasma accelerator with steel electrodes. The influence of gaseous atmosphere parameters has been investigated by carrying out experiments in normal atmospheric conditions and with the introduction of additional oxidant into the plasma discharge. Studies of the structure of synthesized powders and their magnetic properties have been carried out. It has been found that by introducing of additional oxidant it is possible to regulate the phase composition in the direction of increasing the yield of magnetite phase. Specific saturation magnetization decreases with decreasing of the magnetic nanoparticle sizes.
Numerical Simulation of Multilayer Composites Failure under Dynamic Loading
Authors: Zelepugin Sergey A. , Zelepugin Aleksey S.
Published: April 2015

The processes of high-velocity interaction of a projectile with a metal-intermetallic laminate (MIL) composite target were numerically investigated in axisymmetrical geometry using the finite element method. To simulate the failure of the material under high velocity impact, we applied the active-type kinetic model determining the growth of microdamages, which continuously changes the properties of the material and induce the relaxation of stresses. To simulate the brittle-like failure of the intermetallic material under high velocity impact, we modified the kinetic model of failure and included the possibility of failure above Hugoniot elastic limit in the shock wave and sharp drop in strength characteristics if the failure begins. The results show that the depth of penetration depends on the thicknesses of intermetallic and titanium alloy layers. The Al3Ti/Ti-6-4 MIL composite target withstands the impact loading in the case of the ratio about 4/1.
Comparison of Cable Insulation Control in Weak and Strong Electric Fields
Authors: Starikova Nadezda S. , Redko Vitaly V. , Vavilova G.V.
Published: April 2015

In this paper the modern methods of cable products insulation control are referred. A comparison of efficiency of the cable insulation defects control by changing in cable area capacitance is carried out in the strong and weak electric fields. The electric cable can be represented as a cylindrical capacitor, but to simplify the issue the insulation area is represented as a plate capacitor with anisotropic dielectric. The cable insulation model is created in the software Comsol Multyphysic. The effect of the defect dimension on the cable area electric capacitance in a strong and weak electric field is described. Also, the control sensitivity of both methods was assessed and compared with each other. The control sensitivity in a weak electric field is slightly higher for the defects with small size (less than 70% from insulation thickness). The control sensitivity in a strong electric field is considerably higher for the defects with big size (more than 70% from insulation thickness).
Organization of Continuous Process Simulation via E-Network
Authors: Tarakanov Dmitry , Tcapko Gennadii , Tsapko Sergey , Savenko Igor
Published: April 2015

In this article, the proposed approaches to continuous process simulation via E-network are considered in order to construct analytical and simulation models using unified methodology. Principals of continuous process simulation via E-networks using Block Function Diagram programming technology are presented. The construction of continuous process dynamic models is based on the state space method and is implemented using E-network algorithmic simulation scheme.
A Simple Method for Solving Dynamic Problems of Robotics
Authors: Bubenchikov Aleksey M. , Libin Eduard E. , Hudobina Yulia P.
Published: April 2015

In this paper we find a general solution for the action function in the case of a heavy point moving on a sphere using the method of separation of the Hamilton-Jacobi equation variables. The solution contains two constants: the energy of a material point and the momentum projection onto a horizontal direction. We analyze the modes of a spherical pendulum oscillation. It is shown that the solution does not contain any errors of accumulation which are characteristic for evolution problems with long prediction periods.
Mobile Water Treatment Complex
Authors: Goryunov Aleksey G. , Manenti Flavio , Kozin Kirill A. , Baydali Sergey A. , Nadezhdin Igor S. , Potemin Roman V.
Published: April 2015

This article is devoted to review of the existing mobile water treatment complex. Development of resource-efficient technology for water purification is examined by the change of process chart as a function of qualitative composition of a water source. Machine design variants are proposed on the terrain vehicle.
Frequency Domain Sensors and Frequency Measurement Techniques
Authors: Murrieta-Rico Fabian N. , Petranovskii Vitalii , Sergiyenko Oleg Yu. , Hernandez-Balbuena Daniel , Pestryakov Alexey , Tyrsa Vyra
Published: April 2015

Getting fast and accurate information is of paramount importance for most monitoring, data acquisition, and monitoring systems; there are sensors that transform their input into a frequency domain output, this kind of sensors are known as Frequency Domain Sensors (FDS); when the value of the output frequency is measured in a FDS, the value of the sensor’s input (measurand) can be calculated, that is why the frequency measurement in the output of FDS is critical for using such sensors. In this work different kinds of resonant sensors (FDS) are reviewed; also frequency measurement techniques are explored; finally a novel frequency measurement method is proposed and analyzed for resolution improvement in frequency domain sensors.
Predictive Inverse Neurocontrol with Recycled Reference Trajectory
Authors: Zmeu Konstantin V. , Markov Nikolay A. , Notkin Boris S. , Shipitko Ilya A.
Published: April 2015

In this paper, the method of recycled reference trajectory for the plant output is considered within the main framework of the Predictive Inverse Neurocontrol (PIN) technique. The method allows to simplify the PIN controller synthesis and to improve the control quality of a PIN controller when operating with short prediction horizon . Moreover them it offers greater flexibility when choosing the desired of the plant's output response. The advantage of the proposed approach is illustrated by several examples of physical plants control.
The Effect of Electrolytic Hydrogenation on the Plastic Flow of Aluminum Alloy
Authors: Bochkareva Anna V. , Lunev Aleksey G. , Barannikova Svetlana A. , Zuev Lev B.
Published: April 2015

The effect of hydrogen embrittlement on the plastic flow of aluminum alloy D1 was investigated. The studies were performed for the test samples of aluminum alloy subjected to electrolytic hydrogenation in a three electrode electrochemical cell at a controlled constant cathode potential. It is found that the mechanical properties and plastic flow curves of aluminum alloy are affected adversely by hydrogen embrittlement. The hydrogenated counterpart of alloy has a lower degree of ductility relative to the original alloy. The deformation diagrams were examined for the deformed samples of aluminum alloy. These are found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Ludwik-Holomon equation. Microhardness tests were performed for as-treated aluminum alloy D1. Using scanning electron microscopy method, the changes in the fracture surface were investigated.
Determination of Cutting Forces in Oblique Cutting
Authors: Filippov A.V. , Filippova E.O.
Published: April 2015

This study describes the method of determining cutting force components in oblique turning. The scheme of how the investigations were performed is presented. The characteristic curves of cutting force components vs. thickness of the material removed, tool clearance and tool rake angles are shown. The study presents the data, which have been obtained during the experimental investigations and analytically calculated, on how the cutting forces are subject to changes depending on a cutter angle, cutting depth and feed in oblique turning operations. The analysis of approximation of the experimental results and error check of the theoretical calculations relative to the experimental data are given.
Development of Bases and Evaluation Capabilities of the New Tribotechnology for Plain Bearings
Authors: Zelinsky V.V. , Suchilin D.N.
Published: April 2015

The article provides a tribological basis of a new deformation-thermal method to make the surfaces friction materials for plain bearings the improved anti-friction properties (high score resistance, running-in and others) by creating a modified surface layer. The method is based on the use of surface plastic exposure with the subsequent realization of the effect of thermal return of a thin surface layer. A number of most important descriptors of friction ensuring a durability of tribosystems in extreme conditions was considered. Basing of the laws of solid mechanics, principles of material science and regularities of friction and wear, the possibilities of transformation of these values in a favorable direction by using the new method were estimated. The experimental conditions for samples of bearings alloys used in modern reciprocator are given. The results of experimental study of tribodeformational effects for these alloys for a baseline option and with a preliminary modified surface layer are presented. A possibility in principle for the substantial increase of service properties of study group of materials basing on use of the presented method of modification is indicated.
Analysis of Force Dependences of Diamond Burnishing with Different Types of Burnishing Tools
Authors: Chervach Yu.B. , Mezentsev V.A. , Galin N.E. , Kim A.B.
Published: April 2015

The article presents the results of studies on measuring components of force of diamond burnishing of surfaces with variable radius of curvature. The impact of structural elements of burnishing tools of different types on components of burnishing force was analyzed. The impact of different actuators of burnishing tools on components of burnishing force was analyzed. The design of the burnishing tool with an air receiver (bellows with compressed air as an actuator) with a parallelogram-type mounting of the indenter on the four flat posts, which ensures burnishing of profiled and other types of surfaces with constant force Py, was proposed.
Determination of the Energy Parameters of the Shock Mechanism Used to Harden the Surface by Plastic Deformation
Authors: Kirichek A. , Silant’ev S.A.
Published: April 2015

The possibilities of application of various designs of shock mechanisms for hardening by surface plastic deformation were considered. The measuring methods of their energy characteristics were shown.
The Assessment of Durability of Fibre Concretes with Dense Aggregate and Concrete Recyclate from the Results of Permeability and Diffusion Tests
Authors: Stavař Tomáš , Stehlík Michal
Published: April 2015

The mechanical and deformation characteristics of mass concrete are considerably improved by adding long structural fibres. This addition, however, does not always extend the durability of concrete. One of the key factors in the evaluation of durability of fibre concretes is the assessment of permeability of their surface layer using one of the non-destructive methods. In this research, three of these methods were used: two permeation methods with a gaseous medium, TORRENT and CO2 permeability method, and the British ISAT with a liquid medium, on the grounds of their simplicity of application and their possible combinability. The test results show that both TORRENT and ISAT methods can be used to assess the durability of both concrete and fibre concrete with dense aggregate. In the case of concrete containing concrete recyclate, however, the TORRENT method was not effective. Also the method of determining the permeability for CO2 was not suitable for the concrete with concrete recyclate. Even for other concretes this method was too complicated and too dependent on the marginal conditions of the measurement.
Influence of Addition of Fly Ash on Selected Properties of Concrete for Watertight Tunnel Lining
Authors: Hubáček Adam , Jarolím Tomáš , Macháňová Petra
Published: April 2015

The paper deals with the topical theme of concrete for watertight tunnel lining, currently solved in the Czech Republic and abroad. The focus is on high water-tightness of concrete for production of these specific structures and other requirements from the point of durability of concrete for watertight tunnel lining. Experimental work followed previous research and was focused on testing of selected properties of concrete for watertight tunnel lining, either with only cement as a binder (reference mixtures) or with partial replacement of cement with fly ash from Detmarovice power plant. Manufactured specimens of fresh and hardened concrete were used for testing of development of compressive strength, depth of penetration with pressure water and development in hydration heat in time.
The Development of Sprayed Concrete for Extreme Temperatures
Authors: Dufka Ámos , Melichar Tomáš
Published: April 2015

Experience obtained from often tragic road accidents has proven that in a fire the tunnel lining is destructed very intensively by high temperatures. Concrete, usually applied using the sprayed concrete technology (so-called shotcreting) is used for building the linings of road tunnels. The topic of the present article is the development of a concrete mix determined by the sprayed concrete technology so that this material is to the maximum extent resistant to extreme temperature effects occurred in a fire. It is apparent that using this type of concrete is one of the way of increasing the fire safety of road tunnels.
Epoxy Screed as Possible Protection of Floor Surfaces
Authors: Mészárosová Lenka , Tumova Eva , Drochytka Rostislav
Published: April 2015

Nowadays, there is a tendency to use as much of waste products as possible to produce building materials. Every waste product used eliminates the inconvenience associated with the waste disposal process. Consequently, the waste recovery process becomes not only ecological but also economical. Many waste materials, which have not been sufficiently used so far, could very well substitute materials that would otherwise have to be elaborately prepared.
Experimental Determination of Mechanical Characteristics of Four Types of Stones and their Influence on the Construction Machinery Parts Wear
Authors: Lazić Vukić , Arsić Dušan , Nikolić Ružica R. , Hadzima Branislav , Mutavdžić Milan
Published: April 2015

In this paper were experimentally determined properties of four different types of stones and stone aggregates and they were compared to each other with respect to their influence on wear of working parts of machines for preparation and deposition of stones on roads. Rocks, the building stones are obtained from, consist of various types of minerals, namely of physically and chemically homogeneous rocks created within the Earths crust. Here are considered four, most important types of building stones: limestone, dolomite marble, calcite-dolomite marble and andesite. They are being exploited from four sites in Serbia, and they are convenient for deposition of certain layers of the carriageway on roads, streets, airports and foundations on railways, as well as for making different kinds of concrete and asphalt. In the paper are presented results of mineralogical-petrographic, physical-mechanical and special investigations. Wear resistance was also checked on certain samples.
Test of Adhesion and Shear Strength of Polyurethane Adhesives to Cement-Bonded Particleboard
Authors: Nečasová Barbora , Liška Pavel , Šlanhof Jiří
Published: April 2015

This research case was carried out to examine the possibility of usage of cement-bonded composite particleboards as a sheathing of a vented façade system with bonded joints. The potential of bonded joints in combination with composite cladding material was studied and described in more detail as well as verified through experimental measurements. For the purpose of tests spruce timber profiles were chosen for the load bearing substructure. Three types of industrial adhesives intended for structural bonding were selected. The article is focused on the preparation as well as on the subsequent experimental verification of the substructure bonding retention to the cladding and the determination of shear strength under tensile stress at a temperature of (20.0 ± 3) oC and a relative humidity of (55.0 ± 10) %. The test results proved the fact that bonded joints are more than suitable equivalent to the mechanical joints. Furthermore, the series of tests verified the suitability of use of the chosen adhesives in combination with cement-bonded particleboard.
The Influence of Curing and Process of Hydration to Damping Coefficient of Alkali Activated Slag Mortars
Authors: Timcakova Kristýna , Topolář Libor , Rypák Peter
Published: April 2015

Non-destructive acoustic analysis method Impact-echo method as a traditional for civil engineering was used for experiment. This paper reports the experiment during hardening and drying of specimens of alkali activated slag mortars. Alkali activated slag is a material having a great potential to be used in practice. The main drawback of this material is a high level of autogenous and especially drying shrinkage, which causes a deterioration of the mechanical properties. The aim of this paper is introduce the effect of method curing of mortars and time curing on the microstructure of alkali activated slag mortars. An understanding of microstructure performance relationships is the key to true understanding of material behaviours.
The Examination of Waste Industry Sludge Solidification/Stabilization Possibility
Authors: Dohnalkova Bozena , Drochytka Rostislav , Hodul Jakub , Ťažký Tomáš
Published: April 2015

The objective of this paper is to examine the solidification possibilities of selected waste in form of industrial waste sludge, within the paper solidification formulas are designed which are subsequently laboratory tested by compressive strength tests after 28 and 60 days, leachability tests and other tests considering environmental impacts – ecotoxicological tests.
High Strength Alkali Activated Slag Cements with Controlled Setting Times and Early Strength Gain
Authors: Kryvenko Pavlo V. , Petropavlovsky Oleg , Petranek Vit , Pushkar Vasiliy , Vozniuk Grigorii
Published: April 2015

The paper discusses approaches to compositional build-up of high strength alkali activated cements made using water glass as alkaline activator represented by commercial products in a form of powder and liquid. The purpose was to study the influence of fineness of ground granulated blast-furnace slags, admixtures and additives, compatible with alkali activated cements, water glass and mode of manufacturing technology in order to reach high compressive strength (≥ 80 MPa at standard age (28 days)) and early strength (≥ 20 MPa after 3 h of hardening in normal conditions).
The Analysis of the Behavior of Alkali-Activated Materials Applied as a Repair Mortar
Authors: Dufka Ámos , Bodnárová Lenka
Published: April 2015

The paper deals the possibility of alkali activated materials utilization as matrix for repair mortars, determined for rehabilitation of reinforced concrete structures. Alkali activated materials have owing to their specific properties a high potential especially for utilization in materials determined for specific applications. Materials showing in comparison with the cement matrix significantly higher resistance against the effect of chemical substances are the so-called alkali activated materials. One of the essential conditions for the successful use of repair mortars is their sufficient cohesion to the surface respectively with the surface of rehabilitated structures.
Laboratory Burning of Anhydrite from Phosphogypsum
Authors: Gazdič Dominik , Dvořák Karel , Hájková Iveta
Published: April 2015

The objective of this work is a research in the sector of preparation of anhydrite II based sulphate binder made from secondary raw material resources applicable in industry specialised in production of mortar mixtures. In particular it was a laboratory burnout of anhydrite II from phosphogypsum, which is formed during production of phosphoric acid. The selection of burning mode was done upon the results [1]. The selected burning mode influence on mineralogical composition of formed anhydrite was monitored with subsequent setting of basic technological properties and monitoring of hydration process course.
Oxygen Impurity in Germanium Single Crystals Determination by Infrared Spectrometry
Authors: Shimanskii A.F. , Podkopaev O.I. , Baranov Vladimir N.
Published: April 2015

Oxygen impurity in Germanium single crystals has been characterized using Fourier transformed infrared spectrometry. The crystals were grown by Czochralski method in an argon atmosphere. The oxygen concentration in crystals was determined on optical density from the absorption band at 843 cm−1. It was established that oxygen dissolved concentration in Germanium is variable from 0,2·1016 to 1,3·1016 сm−3. The oxygen band maximum shifts toward 856 cm−1 when its concentration increases under the influence of annealing in the oxygen containing atmosphere with ≤ 10−3 Па.
Morphological Transformations of Top Electrodes on YMnO3 Caused by Filamentary Resistive Switching in the Oxide Matrix
Authors: Bogusz Agnieszka , Blaschke Daniel , Bürger Danilo , Schmidt Oliver G. , Schmidt Heidemarie
Published: April 2015

Unipolar resistive switching in YMnO3 with large-scale bottom and small-scale top electrodes is analyzed in detail by tracking the morphological transformations of the top electrodes induced by applied writing voltages. Micro-scale digital images are taken after each subsequent quasi-static current-voltage sweep. Current mapping after electrical investigations indicates a shift in the conductivity at the localized areas of the morphologically transformed top electrodes. Those changes are assigned to the heat induced structural and compositional changes within YMnO3 which lead to the formation and rupture of conductive filaments observed as unipolar resistive switching. Presented results underline the importance of Joule heating in the fostering of resistive switching and its adverse impact on the device endurance.
Morphological and Dimensional Properties of Colloidal Silver Nanoparticles Prepared under Microwave Irradiation
Authors: Harjono Harjono , Yulizar Yoki
Published: April 2015

In this paper we report the effect of irradiation time on the morphological and dimensional properties of colloidal silver nanoparticles (AgNPs) using sodium citrate and silver nitrate as reductant and oxidant, respectively under microwave irradiation. The prepared NPs were characterized by UV–vis spectroscopy, Particle size analyzer (PSA), transmission electron microscopy (TEM) and selected areas electron diffraction (SAED). The formation of Ag NPs was confirmed by the appearance of a surface plasmon absorption between 411-425 nm. PSA showed that the colloidal nanoparticles had a diameters ranging from 25.5-41.2 nm. TEM images showed that the diameter of the silver nanoparticles in accordance with the results obtained using PSA. The rings patterns are in good agreement with the standard values of the facecentered-cubic form of silver nanocrystals.
Coal Fly Ash as a Dual Site Material for Cr(VI) Adsorption: Comparation between Single Site and Dual Site Isotherm Models
Authors: Astuti Widi , Sulistyaningsih Triastuti , Fardhyanti Dewi Selvia
Published: April 2015

The major problem in coal-based thermal power plants is related to solid waste called coal fly ash (CFA). CFA is mainly composed of some oxides including SiO2, Al2O3 having active site and unburned carbon as a mesopore that enables it to act as a dual site adsorbent for heavy metals including Cr (VI). To get different characters of dual site, CFA was treated by sulfuric acid (H2SO4) at different concentrations, temperatures and reaction time. Furthermore, treated CFA were used as an adsorbent to adsorb Cr (VI) in aqueous solutions. Equilibrium data were evaluated by single site and dual site isotherm models. It can be concluded, although unburned carbon contributes on the Cr (VI) adsorption, the existence of unburned carbon decreases the amount of Cr (VI) adsorbed because unburned carbon can plug active sites where dominant adsorption occurs. However, dual site isotherm model yielded excellent fit with equilibrium data.
The Crystal Structure and Ionic Conductivity of Layered Composite of SDC-YSZ-SDC
Authors: Rahmawati Fitria , Syahroni Ahmad , Syarif Dani G.
Published: April 2015

Researchon thepreparation of ceria based materialfor electrolyteof solid oxide fuelcellhasbeen conducted. The Sm0.2Ce0.8O1.9(SDC) was prepared by sol-gel method and the layered composites of SDC with Y0.08Zr0.92O3-δwerepreparedbyscreenprintingmethod.This research aims to studythecrystal structure and its conductivitycharacter. XRDmeasurementequippedwithLeBailrefinementshowsthatSDCiscrystallizedin cubic structure with space group of Fm3m.Theaddition ofYSZ into SDC does not changeitscrystal structure. However, the cell parameter of SDC is reduced from 5.434036(2) Å to 5.433(0) Å. At 600 °C, SDC has electronic conductivity that indicates the presence of electrons migration that can promotes short circuit during fuel cell operation. The combination of SDC with YSZ forming a layered composite of SDC-YSZ-SDC could reduce the electronicconductivity,eventhoughitsionicconductivityisalsobecomelowerthansingleSDCatthe same temperature.