International Journal of Materials


ISSN: 2313-0555
Volume 1, 2014

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

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Volume 1, 2014


Title of the Paper: Some Aspects of Chemical Transformations of Trinitrotoluene

 

Authors: Olga V. Kovalchukova, Konstantin I. Kobrakov

Pages: 152-158

Abstract: Some new aspects of chemical transformations of trinitrotoluene into products of civil needs are reviewed. The new approach to a cheap and ecological way of chemical modification of nitro aromatic compounds into non explosive products are described. Basing on the proposed reactions, some new hydroxyimino and azo compounds and their metal complexes were synthezised and described by spectroscopic and theoretical methods. Their possible ways of application are proposed.


Title of the Paper: Mechanical Properties of a Particle-Reinforced Zr Bulk Metallic Glass

 

Authors: G. S. E. Antipas

Pages: 149-151

Abstract: The mechanical properties of a Zr-based bulk metallic glass were improved via dispersion of graphite particles into the alloy matrix. The resulting material had high plasticity, superior yield strength and good elasticity. The use of reinforcement particles also suppressed heterogeneous nucleation. Increased alloy plasticity of up to 20% was achieved without sacrificing the high yield strength of the metallic glass. The addition of graphite was also found to improve the thermal stability of the reinforced glass compared to that of the monolithic alloy.


Title of the Paper: Diagnostics of Ultra-Thin Tungsten Films on Silicon Substrate Using Atomic Force Microscopy

 

Authors: Milan Navrátil, Vojtěch Křesálek, František Hruška, Tomáš Martínek, Josef Kudělka, Jaroslav Sobota

Pages: 142-148

Abstract: In this article, atomic force microscopy method was used for diagnostics of ultra-thin tungsten films which were deposited on silicon substrate. Radio frequency magnetron sputtering method was used for tungsten deposition on the surface. According to atomic forces between the tip and the sample, topographical structures were measured and imaged.


Title of the Paper: Multilayer Growth of AlxGa1-xAs/GaAs Thin Films Using an Elemental-Arsenic-Based-MOCVD System

 

Authors: R. Castillo-Ojeda, R. Sánchez-Espíndola, J. Díaz-Reyes, M. Galván-Arellano, R. Peña-Sierra, J. F. Sánchez-Ramírez, J. Martínez-Juárez

Pages: 134-141

Abstract: GaAs and its alloys have proved to be successful semiconductor materials for the optoelectronic device industry, unfortunately its production by MOCVD systems require the use of a highly toxic compound as is the arsine. In this work we report some results of the studies related to the growth and characterization of AlxGa1-xAs /GaAs/ AlxGa1-xAs epitaxial layers obtained by Metal Organic Chemical Vapor Deposition (MOCVD) using solid arsenic instead arsine. The main goal is to explore the ability of this system to grow multilayer structures like quantum wells. The use of metallic arsenic could introduce important differences in the growth process due to the absence of the hydride group V precursor (AsH3), which is manifested in the electrical and optical characteristics of both GaAs and AlxGa1-xAs layers. The gallium and aluminum precursors were trimethylgallium (TMGa) and trimethylaluminum (TMAl), respectively. The arsenic was introduced by diffusion on the growth zone using a metallic arsenic source. The most serious difficulty on growing AlxGa1-xAs, is the incorporation of large amount of impurities as carbon and oxygen. The characterization of these epilayers was performed using Hall effect, low-temperature photoluminescence, Raman spectroscopy, Atomic Force Microscopy and Secondary Ion Mass Spectroscopy (SIMS).


Title of the Paper: Influence of Ionizing Beta Radiation on the Adhesion Properties and Strength of Bonded Joint of Linear Low Density Polyethylene

 

Authors: Martin Bednarik, David Manas, Miroslav Manas, Michal Stanek, Jan Navratil, Ales Mizera

Pages: 126-133

Abstract: In this study there was found that ionizing beta radiation increased the strength of bonded joints and improved the adhesion properties of linear low-density polyethylene (LLDPE). Generally, for the formation of quality bonded joint it is important to wet the adhesive bonding surface well. Wettability is characterized by the contact angle of wetting. The liquid has to have a lower surface tension than the solid in order to be able to wet the solid substance. The measurement results indicated that ionizing beta radiation was a very effective tool for the improvement of adhesive properties and increased the strength of bonded joints of linear low-density polyethylene. Bonded surfaces with ionizing beta radiation doses of 0, 33, 66, 99, 132, 165, and 198 kGy were irradiated. The best results were achieved by irradiation at dose of 132 kGy by which the highest surface energy and the highest strength of bonded joints of LLDPE were achieved. The strength of bonded joints after irradiation was increased up to 260 % compared to untreated material. A similar trend was observed even for contact angle of wetting and surface energy.


Title of the Paper: Metallographic Analysis of the 7G-Tronic Automatic Gearbox Housing

 

Authors: Ion Silviu Borozan, Veronica Argeşanu, Inocenţiu Maniu, Raul Miklos Kulcsar, Mihaela Jula

Pages: 119-125

Abstract: The paper consists on the metallographic analysis of the 7G Tronic automatic gearbox material housing in order to establish the materials that are included in the housing and their percentage. This helps to improve the housing characteristics and also the molding process and its advantages and disadvantages.


Title of the Paper: Material Properties´ Comparison of PA6/HDPEx Blends

 

Authors: Jan Navratil, Miroslav Manas, Michal Stanek, David Manas, Martin Bednarik, Ales Mizera

Pages: 111-118

Abstract: Irradiation of thermoplastics is a very spread material modification for improving their properties, yet little research has been done to investigate possible utilization of such modified materials after the end of their lifetime. This research paper tries to give possible solution of using this material as a filler into some other one. The emphasis is put on utilization of irradiated high-density polyethylene (HDPEx) which has been blended with non-modified polyamide 6 (PA6). Two concentrations of tested blends were prepared (10 and 30 %) when raw PA6 matrix was in a form of granules and raw HDPEx waste in a form of grit. Three mechanical properties tests were performed in order to get the most complex results of the resulting mechanical behavior. Tensile properties were tested at two temperatures and at both of them was a decline observed. Elastic modulus decreased from 3591 to 1815 MPa at 24 °C and from 533 to 294 at 80 °C. Impact toughness was investigated via impact charpy notched test where the results varied greatly. Last observed property was hardness where it slightly declined from 77.8 to 74.4 Shore D. All results show that HDPEx waste can be processed as a filler; however when mixed with PA6 there is significant loss of original PA6 properties.


Title of the Paper: Disposing Waste Demolition in Concrete as Aggregate Replacement

 

Authors: Mahmoud Nili, Nader Biglarijoo, Seyed Mehdi Hosseinian, Siavash Ahmadi

Pages: 105-110

Abstract: In this study, the possibility of substituting waste materials with natural aggregates is considered. Used waste materials are limited to recycled concrete aggregate (RCA), waste glass (WG) and waste plastic (WP). Substitution percent (by weight) for all three waste materials are (0, 5, 10, 15 and 20). RCA is substituted by both fine and coarse aggregates, while WG and WP are substituted only as fine aggregate in concrete mixtures. Workability, compressive strength, tensile strength, flexural strength, hardened unit weight, electrical resistivity, dynamic modulus of elasticity and water absorption of the concrete are evaluated. WG and RCA (fine and coarse) had no remarkable effect on mechanical properties of concrete, while WP decreased mechanical properties and hardened unit weight remarkably. Workability reduced by substituting WP and RCA by natural aggregates, while WG had no influences on slump value. Water absorption and electrical resistivity of concretes containing WG and WP were higher than those of control concrete.


Title of the Paper: Fatigue Life of Carburized Steel Specimens under Push-Pull Loading

 

Authors: Štěpán Major, Štěpán Hubálovský, Josef Šedivý, Jan Bryscejn

Pages: 99-104

Abstract: Various articles dedicated to effect of surface layer on fatigue life have been published in recent years. However, most of these articles are dedicated to the steels with nitride layer and only limited number of papers is dedicated to the carburizing. Results of extended experimental investigation of fatigue resistance of gas and low pressure carburized specimens made of the low-alloy high-strength steel are presented. The specimens were subjected to push-pull loading of different R-ratios. The application of plasma carburizing can lead to about 25% increase in the fatigue resistance in the high cycle region (over 105 cycles). On the contrary, in the case of low cycle fatigue often has a negative effect on the service life.


Title of the Paper: Atomic Configuration, Band Structure and Stability of Fluorinated Carbon Nanotubes

 

Authors: Alexander A. Ganin, Larissa A. Bityutskaya, Eugeniy N. Bormontov

Pages: 93-98

Abstract: The article discusses the model and the results of an ab initio calculation within the density functional theory of the band structure and fluorocarbon bond energy in different isomers of fluorine derivatives of single walled carbon nanotubes. The website developed for the generation of functionali¬zed nanotubes’ atomic configuration is presented. Also a system of seven geometrical parameters for the tube’s geometry definition is proposed. Much attention is given to the changes in the electronic structure of carbon nanotubes due to the functionalization with fluorine. From the dependencies of the fundamental parameters (such as the band gap, Fermi energy and fluorocarbon bond energy) of the armchair and zigzag nanotubes on the diameter the corresponding values for graphene are estimated.


Title of the Paper: Nano-Hardness of PA12 after Cross-Linking Due to Beta Radiation

 

Authors: M. Ovsik, D. Manas, M. Manas, M. Stanek, M. Bednarik, P. Kratky, A. Mizera

Pages: 84-92

Abstract: This article deals with the influence of different doses of β - radiation on nano-mechanical properties of Polyamide 12. These nano-mechanical properties were measured by the DSI (Depth Sensing Indentation) method on samples which were non-irradiated and irradiated by different doses of the β - radiation. The aim of the article is to find out the influence of the radiation on the nano-hardness of the modified PA12.


Title of the Paper: Utilization of FBC Ash in Autoclaved Aerated Concrete Technology

 

Authors: Vit Cerny, Rostislav Drochytka

Pages: 79-83

Abstract: There are still a lot of coal combustion products waiting for utilization in the Czech Republic. One of suitable building materials is fly ash aerated concrete. It is as a modern material combining high use value with environmental aspects of its production. Autoclaved aerated concrete is also one of the ways to use besides fly ashes from pulverized boilers fluidized bed combustion ashes. Significant advantage of the utilization of these CCPs from fluidized bed combustion is a saving of lime as the most expensive raw material for the production of aerated concrete. This paper deals about the possibility of fluidized fly ashes utilization in the technology of autoclaved aerated concrete, rheological properties of the mixture, the plastic strength, compressive strength and density of aerated concrete. Another topic of this paper is current state of use and legislative background of use of CCPs in the Czech Republic. Paper also verifies the autoclaving time influence on tobermoritic phase developments and to this related compressive strength of the fly ash aerated concrete.


Title of the Paper: Influence of Type and Amount of Recycled Material to Mechanical Properties of PC

 

Authors: V. Senkerik, M. Stanek, M. Manas, D. Manas, A. Skrobak, J. Navratil

Pages: 71-78

Abstract: The articles describe analyses influence of type and amount of recycled material on the mechanical properties of material. Polycarbonate was inspected material. Specimens were prepared by the mostly used technology for production products, which is injection molding. Several recycled materials were made, all from original material. Samples with different percentage amount and a type of recycled material were subsequently tested by mechanical testing. Included tests were tensile tests and Charpy impact test. Testing was conducted at different temperatures; at reduced, ambient and increased temperatures. The results of these tests were to determine appropriate technology preparation and optimum percentage of recycled content in tested materials. After the first recycling there was a change of mechanical properties; improvement in notch toughness and a small change in ultimate strength and modulus.


Title of the Paper: Electron Structure and Optical Properties of Cd1-XMnXTe Thin Films

 

Authors: M. A. Mehrabova, I. R. Nuriyev, H. S. Orujov

Pages: 63-70

Abstract: Band structure and DOS have been calculated for Cd1-хMnхTe (x=0.0625, x=0.0312, x=0.0156) semimagnetic semiconductors by ab-initio method using the Atomistix Toolkit program. It has been determined that with an increase in Mn quantity, the energy gap increases and lattice parameter decreases. The calculated magnetic moment for Mn atom is found to be equal to 5μB. It was revealed that the antiferromagnetic phase is stable in Cd1-xMnxTe. The theoretical results are in good agreement with the experimental data obtained by us. It has been synthesized Cd1-хMnхTe solid solutions (х=0.01, 0.03, 0.05). Thin films of the given solid solutions were obtained on the glass and mica substrates. Lattice parameters and compositions of the obtained samples were defined with X-ray diffraction method. It has been defined the optimum conditions for obtaining of Cd1-хMnхTe (x=0.01, 0.03, 0.05) solid solutions’ thin films on the glass and mica substrates. With increasing of substrate temperature, films obtained on the glass substrates are crystallized, and the films obtained on the mica substrates became more perfect. The homogeneity of the composition of synthesized solid solutions have been established by EPR method.


Title of the Paper: How Surface Roughness of Mold Cavity Influence the Material Flow

 

Authors: M. Stanek, D. Manas, M. Manas, V. Senkerik

Pages: 55-62

Abstract: Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. This paper shows the influence of cavity surface roughness, polymer material (with different flow properties) and technological parameters on the flow length of polymers into mold cavity. Application of the measurement results may have significant influence on the production of shaping parts of the injection molds especially in changing the so far used processes and substituting them by less costly production processes which might increase the competitiveness of the tool producers and shorten the time between product plan and its implementation. Because the finishing operations of machining are very time and money consuming leading to high costs of the tool production. Six types of thermoplastic polymers with different flow properties were tested in this paper.


Title of the Paper: Calculation of Cost Functions by Leather Fatliquoring for Its Optimization

 

Authors: H. Charvatova, D. Janacova, V. Vasek, K. Kolomaznik, P. Mokrejs

Pages: 49-54

Abstract: The paper deals with the economic aspects of the tannery operation of leather fatliquoring. It describes a mathematical model of the studied process and its use in computing of the cost function depending on the operating conditions. The results can be used to determine the optimum process realization to the purpose of saving energy and raw materials.


Title of the Paper: Injection Molding of Rubber Compound Influenced by Surface Roughness

 

Authors: M. Stanek, D. Manas, M. Manas, K. Kyas, V. Senkerik, A. Skrobak, J. Navratil

Pages: 41-48

Abstract: Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. This paper shows the influence of cavity surface roughness and technological parameters on the flow length of rubber into mold cavity. The fluidity of polymers is affected by many parameters (mold design, melt temperature, injection rate and pressures) and by the flow properties of polymers. Results of the experiments carried out with selected types of rubber compounds proved a minimal influence of surface roughness of the runners on the polymer melt flow. This considers excluding (if the conditions allow it) the very complex and expensive finishing operations from the technological process as the influence of the surface roughness on the flow characteristics does not seem to play as important role as was previously thought. Application of the measurement results may have significant influence on the production of shaping parts of the injection molds especially in changing the so far used processes and substituting them by less costly production processes which might increase the competitiveness of the tool producers and shorten the time between product plan and its implementation.


Title of the Paper: The Effect of Fire to the Steel Frame Structure

 

Authors: Lenka Lausová, Iveta Skotnicová, Pavlína Matečková, Jiří Brožovský

Pages: 33-40

Abstract: The paper describes experimental, numerical and analytical analysis of the statically indeterminate steel frame structure loaded by static load in case of fire situation. There is solved the effect of non-uniformly distributed temperature over the section of statically indeterminate structure. In the work there are compared results from the experiment realised in the thermal technical chamber of VSB-TU Ostrava, numerical modelling using the finite element method in the ANSYS software and analytical approach, where the geometric and physical nonlinearity is respected.


Title of the Paper: Properties of LDPE with the Filler of Recycled Irradiated HDPE by Accelerated Electrons

 

Authors: A. Mizera, J. Navratil, M. Manas, D. Manas, M. Stanek, M. Bednarik, M. Reznicek

Pages: 25-32

Abstract: Irradiation of thermoplastics is a well-known modification used for improving of cheap commodity plastics; however, little research was carried-out on recyclation of such modified materials. This research paper gives possible solution of utilization of recycled irradiated high-density polyethylene (HDPE). A powder of recycled irradiated HDPE was used as filler into pure low-density polyethylene (LDPE) and tensile test was performed. Materials were mixed together in concentrations from 10 to 60 % of the filler and injection molded to produce test specimens. Tensile test was performed at ambient – 23°C temperatures. Observed results were Young´s Modulus and Ultimate Tensile Strength to determine tensile behavior and to describe influence of the filler on this behavior. Findings from this research work could help to solve problems with the utilization of irradiation cross-linked PE in the end of its lifetime.


Title of the Paper: Effect of Index of Non-Newtonian Behavior on Curing Rate during Injection Molding of Rubber Compound

 

Authors: Kamil Kyas, Michal Stanek, Jan Navratil, Miroslav Manas, David Manas, Mizera Ales, Adam Skrobak

Pages: 17-24

Abstract: Right used computational analyses are commonly good tool for technical industry to improve process. This paper shows using computational analysis during injection molding process and shows using computational analysis to improve the injection molding process. The main aim of the paper is presenting differences between effects on non-Newtonian behavior on cure rate in final product in rubber process. It was found that for specific geometry and processing conditions, increase in the index of non-Newtonian behaviour increases the curing rate due to viscous dissipation taking place at the flow domain walls. It was shown for variable flow rate.


Title of the Paper: Mathematical Modelling and Description of the Technological Process of Aluminum Anodic Oxidation by Using the Neural Networks

 

Authors: A. Vagaská, P.Michal, I. Bukovský, M. Gombár, J. Kmec

Pages: 9-16

Abstract: In this paper the usage of neural networks and Design of Experiments methodology in order to control and optimize the technological process of aluminium anodic oxidation is presented. The influence of the input factors on the resulting AAO (anodic aluminum oxide) film thickness was monitored at defined current density of 4.00 A∙dm-2, 5.00 A∙dm-2 and 6.00 A∙dm-2.The thickness of the formed AAO layer has been investigated as the relationship of physical and chemical factors acting during the anodic oxide process. A higher-order neural unit based on the iterative Levenber-Maquardt algorithm was used to evaluate experimentally obtained data in order to predict the thickness of the resulting AAO layer and determine the optimum selection of process conditions.


Title of the Paper: Comparison of Properties between Irradiated PA11 and PA12 by Accelerated Electrons

 

Authors: A. Mizera, M. Manas, Z. Holik, D. Manas, M. Stanek, J. Navratil, M. Bednarik, M. Reznicek

Pages: 1-8

Abstract: Radiation processing involves the use of natural or manmade sources of high energy radiation on an industrial scale. The principle of radiation processing is the ability of high energy radiation to produce reactive cations, anions and free radicals in materials. The industrial applications of the radiation processing of plastics and composites include polymerization, cross-linking, degradation and grafting. Radiation processing mainly involves the use of either electron beams from electron accelerators or gamma radiation from Cobalt-60 sources. The PA11 polyamide 11 and the PA12 polyamide 12 tested showed significant changes of temperature stability and mechanical properties after irradiation. From this point of view, new applications could also be seen in areas with service temperatures higher than their former melting point. The comparison of the temperature stability and mechanical properties of irradiated and non-irradiated PA11 and 12 are presented in this paper.