bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on the Effect of Geometrical Shape of Cold Direct Extrusion on Commercially Pure Aluminum Alloyed by 4% Cu
Authors: Zaid Adnan I.O. , Al-Qawabah S.M.A.
Published: May 2015

Al-4% Cu alloys are now widely used in many engineering applications especially in robotic, aerospace and vibration control area. The main problem arises from the weakness of their mechanical characteristics. Therefore, this study is directed towards enhancing the mechanical properties through severe plastic deformation, hence it is anticipated that cold direct extrusion process may enhance their mechanical behavior. This was performed through using three different cross sectional dies namely; circular, square, and rectangular that have the same cross sectional area. The general microstructure, microhardness, and compression tests were performed on each specimen produced before and after extrusion for Al and Al-4% Cu alloy. It was found that the maximum enhancement in mechanical behavior was achieved after extrusion through the rectangular shape for both Al and Al-4% Cu alloy at 0.2 strain by 143% for Al and 134.8% for Al-4%Cu wt.; similarly the hardness of both of them was improved where a maximum of 141.8 % was obtained for Al-4% Cu wt. in case of rectangular cross sectional die.
Electrospun Gelatin Fiber Bundles by Self-Bundling Electrospinning
Authors: Thitiwongsawet Patcharaporn , Wisesanupong Boonchuay , Pukkanasut Supatcharee
Published: May 2015

Electrospun gelatin fiber bundles were successfully prepared by self-bundling electrospinning process. A solvent mixture of 80:20 v/v acetic acid: N,N-dimethylacetamide was used as solvent for gelatin. Self-bundling was achieved by using of a grounded needle tip at the beginning of electrospinning process. Gelatin fiber bundles were fabricated from 30% w/v gelatin solutions with addition of pyridinium formate (PF) at concentrations of 3 and 5% w/v. The averaged diameters of single fiber were 452 and 410 nm, respectively; whereas, the averaged diameter of bundles were 17.2 and 22.3 μm, respectively. Viscosity and electrical conductivity of solutions were important parameters for achieving self-bundling electrospinning. Gelatin solutions with optimum electrical conductivity and viscosity could yield bundles by self-bundling electrospinning.
Cube Texture Formation in Ni-8at.%W Alloy Substrates Effected by the Initial Grain Size of Ingot
Authors: Meng Yi Chen , Suo Hongli , Tian Hui , Ma Lin , Wang Yi , Liang Ya Ru , Liu Min
Published: May 2015

The high critical current density of YBCO-coated conductors prepared by rolling assisted biaxially textured substrate technic is mostly based on the high quality cube-textured substrates. In this paper, the effect of initial grain size of ingot on the microstructure and texture evolutions during cold rolling has been investigated in high alloyed Ni8W ingots, which can affect the cube texture formation in Ni8W alloy substrates subsequently. Finally, high quality cube texture had been obtained in Ni8W alloy substrate with fine initial grain size prepared by advanced SPS technology.
Preparation and Characterization of Hydrogels Based on Chitsoan/Polyvinyl Alcohol Blends
Authors: Zitouni Mohammed Amine , Borsali Kara Slimane Sofia
Published: May 2015

In this study, a series of poly (vinyl alcohol) (PVA)/chitosan (CS) hydrogels with different weight ratio of PVA to CS were prepared by freezing-thawing (F-T) method. The structure, morphology, and crystallinity of hydrogels were investigated by Fourier Transform Infrared (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). FTIR demonstrated the presence of strong intermolecular hydrogen bonds between CS and PVA molecules. SEM images showed that the higher the chitosan, the greater the porous size of the hydrogel and DSC confirmed that crystallinity is higher when PVA is more in hydrogel. The mechanical properties of these hydrogels were studied by rheometry. The study of swelling ability demonstrated that the hydrogel developed with PVA and Cs was more swellable than that with PVA only because of its cross-linking interaction with PVA.
An Experimental Investigation on Specific Heat Capacity and Enthalpy of Al 6061-SiC-Gr Hybrid Metal Matrix Composites Using Differential Scanning Calorimetry
Authors: Krishna S.A. Mohan , Shridhar T.N. , Krishnamurthy L.
Published: May 2015

Metal matrix composites are regarded to be one of the most predominant classifications in composites. The thermal characterization of metal matrix composites using Differential Scanning Calorimetry is a resourceful technique for the determination of heat flow distribution, specific heat capacity and enthalpy. The measurement of the thermal properties of materials is fundamental for the better understanding of the thermal design. Differential Scanning Calorimeter (DSC) is a technique that measures the difference in the heat flow to a sample and to a reference sample as a direct function of time or temperature under heating, cooling or isothermal conditions. In the present research, evaluation of specific heat capacity and enthalpy are accomplished for Al 6061, Silicon Carbide and Graphite hybrid metal matrix composites from room temperature to 300°C based on heat flow response. Based on endothermic and exothermic processes, the heat flow can be shown clearly depending on heating rate and gradual variation in temperature. The heat flow and heating rate are beneficial in the estimation of specific heat capacity for different percentage compositions of the hybrid composites.
Synthesis, Characterization, and Antimicrobial Activities of New Organic-Inorganic Hybird Compound Based on Polyoxovanadate and Metal-Schiff-Base Complex
Authors: Wu Qiong , Ji Xiao Lin , Jing Lu , Ju Hong Ping , Wang Hai
Published: May 2015

The reaction of polyoxovanadate and metal-Schiff base complex resulted in the formation of a new organic-inorganic hybrid compounds with the formula Na2[Mn (Salen)(H2O)2]4[V10O28]·9H2O (1) (salen=N,N’-ethylene-bis (salicylideneiminate). Compound 1 have been structurally characterized by IR, UV-vis spectroscopy and single crystal X-ray diffraction. Crystal data for 1: Triclinic, P-1, a=14.1123(3)Å, b=13.9397(7) Å, c=14.2564(5)Å, α=65.4160(9)°, β=81.3920(6)°, γ=89.5740(7) °. Structural analyses revealed that compound 1 represent a rare example of isopolyoxovanadate based metal-Schiff-base complexes, moreover, this is the first POM based metal Schiff-base complex isolated in aqueous solution medium, which may also propose a green chemical way to the synthesis of POM based hybrid. Compare with isopolyoxovanadate precusor Na6 [V10O28], compound 1 exhibit higher antimicrobial activities against human cancer cell, the phenomenon can be explained by the synergetic effect between POM and Schiff-base complex.
Durability Performance of Cement Composites Containing Ground Granulated Blast Furnace Slag
Authors: Kovalcikova Martina , Eštoková Adriana , Luptáková Alena
Published: May 2015

The hydraulic properties of granulated blast-furnace slags have been studied for nearly 200 years, and use of slag in mortars and concretes dates back more than a hundred years. The use of ground blast furnace slag, added as a replacement for a portion of the portland cement, has gained increasing acceptance in recent years. The effects of sulphur-oxidizing bacteria Acidithiobacillusthiooxidans on concrete mixture with addition of ground granulated blast furnace slag compared to mixture without any additives were investigated in laboratory over a period of 91 days. A laboratory study was conducted to comparison the performance of concrete samples in terms of a concrete deterioration influenced by the leaching of calcium compounds from the cement matrix. The changes in the elemental concentrations of calcium ions in leachates were measured by using X – ray fluorescence method. Experimental studies confirmed: bacteria Acidithiobacillus thiooxidans caused much intensive calcium release from the concrete matrices into the solution; the higher resistance of concrete mixture with 65 % wt. slag addition was not confirmed.
Interfacial and Demulsification Properties of Janus Type Magnetic Nanoparticles
Authors: Ali Nisar , Zhang Qiu Yu , Zhang Bao Liang , Zaman Wajid , Ali Sarmad
Published: May 2015

Water-in-oil emulsions are formed during crude oil production. Some natural surfactants (asphaltenes) aggregates are known to form viscoelastic film preventing coalescence of emulsified water droplets. The present research work investigates the interfacial properties and demulsifying capacity of Janus type magnetic nanoparticles. poly (methylmethacrylate-acrylicacid-divinylbenzene) iron oxide Janus nanoparticles with Interfacially active P(MMA-AA-DVB) block copolymer and iron oxide (magnetic) shows excellent interfacial and magnetic properties. Experiments performed at the oil-water interface indicates that Janus particles adsorb at the oil - water interface and separate the emulsified water from the external magnetic field. The external magnetic play important role demulsification of magnetically tagged emulsified water droplets, producing smaller volumes of sludge and decrease the hydrocarbon loss to waste aqueous phase. The chemical bonding of interfacially active P(MMA-AA-DVB) grafted with magnetic nanoparticles and the magnetic property of P(MMA-AA-DVB)/Fe3O4 allowed the used Janus nanoparticles to be readily recycled by magnetic separation and regenerated by solvent washing.
Thermal Conductivity of Silicon-Graphene Nanoribbon (SiGNR): An Equilibrium Molecular Dynamics (EMD) Simulation
Authors: Alipala Cachey Girly G. , Paylaga Giovanni J. , Paylaga Naomi Tabudlong , Bantaculo Rolando V.
Published: May 2015

Silicon-graphene nanoribbon (SiGNR), an allotrope of silicon carbide with sp2 hybridization, gains interest nowadays in the world of two-dimensional materials. In this study, the thermal conductivity of SiGNR is investigated and compared to that of graphene nanoribbon (GNR) and silicene nanoribbon (SiNR). Molecular Dynamics using Tersoff potential through Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) using the Green-Kubo method is employed to predict the thermal conductivity of silicon-graphene materials with armchair chirality. The temperature is varied from 50 K, 77 K, 150 K, 300 K, 500 K, 700 K, 1000 K, 1200 K, and 1500 K with a fixed width of 10 nm and length of 50 nm. The length of the materials is also varied from 10 nm, 20 nm, 30 nm, 40 nm and 50 nm with a fixed temperature of 300 K. Our results show that the thermal conductivity of SiGNR is higher than that of GNR and is approximately 50% larger at room temperature, which may be attributed to the presence of Si atoms inducing larger flexural phonon density of states than in GNR and SiNR. Also, the thermal conductivity of SiGNR follows the same length-dependent behavior of GNR due to its long mean free path. This study presents new insights into the thermal properties of silicon-graphene which will be significant for nanoelectronic applications.
Molecular Dynamics Simulation of the Thermal Conductivity of Silicon-Germanene Nanoribbon (SiGeNR): A Comparison with Silicene Nanoribbon (SiNR) and Germanene Nanoribbon (GeNR)
Authors: Tagalog Jessa Mae P. , Alipala Cachey Girly G. , Paylaga Giovanni J. , Paylaga Naomi Tabudlong , Bantaculo Rolando V.
Published: May 2015

This study examines the nature of thermal transport properties of single layer two-dimensional honeycomb structures of silicon-germanene nanoribbon (SiGeNR), silicene nanoribbon (SiNR) and germanene nanoribbon (GeNR) which have not yet been characterized experimentally. SiGeNR, SiNR and GeNR are the allotropes of silicon-germanium, silicon and germanium, respectively, with sp2 hybridization. The thermal conductivity of the materials has been investigated using Tersoff potential through LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) by performing the molecular-dynamics simulations. The temperature is varied (50 K, 77 K, 150 K, 300 K, 500 K, 700 K, 1000 K, and 1200 K) with fixed nanoribbon dimension of 50 nm × 10 nm. The length is also varied (10 nm, 20 nm, 30 nm, 40 nm, and 50 nm) while the temperature is fixed at room temperature and the width is also fixed at 10 nm. The obtained results showed that the thermal conductivity of SiGeNR at room temperature is approximately 10 times higher than GeNR and approximately 6 times higher compared to SiNR. The thermal conductivity increases as the temperature is increased from 50 K – 300 K, and as the temperature is further increased, the thermal conductivity decreases with temperature. Moreover, the thermal conductivity in SiGeNR, SiNR, and GeNR increases as the length is being increased. Predicting new features of SiGeNR, SiNR and GeNR open new possibilities for nanoelectronic device applications of group IV two-dimensional materials.
Nonlinear Multiresponse Parameter Estimation Using Simplex Optimization Method
Authors: Mohammad A. Al Saleh , Abdirahman A. Yussuf
Published: May 2015

Polyolefin molecular architectures are designed according to customer needs and demands. Hence, it is essential to determine the catalytic behavior that gives the polymer the characteristics it needs to meet the market requirements. Today most of the industrial polyolefin production depends on multiple-site-type catalysts such as Ziegler-Natta catalysts. In this work a methodology to estimate parameters for polyolefin multiple-site-type catalysts was presented. The sequence length distribution data were simulated using Zeroth-order and First-order Markovian models. These simulated data were used to test the robustness of the optimization method. The optimization method used was able to retrieve and comprehend the proper probabilistic models and provide acceptable polymerization parameters estimates.
Investigation of Thermal and Rheological Properties of Polypropylene and Montmorillonite (MMT) Nanocomposites
Authors: Yussuf A.A. , Al-Saleh M.A. , Al-Enezi S.T.
Published: May 2015

The performances of PP/MMT nanocomposite (70μm thick films), in terms of thermal and rheological properties were investigated. A twin-screw extruder was used to compound PP, MMT, compatibilizer, and extruded nanocomposite films were collected for test. All results were compared and the influence of MMT contents on the final properties were observed and reported. The thermal properties of PP had improved by increasing MMT content from 0-3 phr. However at 4 phr thermal stability of the nanocomposite had slightly dropped. In terms of rhelogical properties, the addition of MMT to the PP blend increased the complex viscosity of the nanocomposites, particularly at low frequency regions.
Improvement of Geotechnical Characteristics of Clay Soils Using Lime
Authors: Louafi Bahia , Hadef Billal , Bahar Ramdane
Published: May 2015

This study presents the results of an experimental work carried out to investigate the effects of treatment of fine bentonite clay using various contents of lime. Tests conducted verified substantial changes and significant improvement in physical and mechanical characteristics of the clay. Techniques including ultrasonic tests and unconfined compression were utilized for a series of lime content (0%,2%, 4% and 6%) for variable curing times.
The studied clay soils revealed that lime treated clays get changed and improved with regard to particular geotechnical characteristics due to cation exchanges, particle rearrangements and pozzolanic reactions. The analysis of ultrasonic tests and compressive strength showed a process of gradual increase in strength and compactness of the reaction products over time. For an optimum dose and extended curing time, the stabilized soil acts as a rock.
A New Organic-Inorganic Hybrid Based on L-Arginine and Polyoxoanion
Authors: Wu Qiong , Lu Jing , Ji Xiao Lin , Zou Tao Yu , Qiao Zhen Fang , Ju Hong Ping , Wang Hai
Published: May 2015

Modifying polyoxometalates with organic and/or metal-organic moieties is a widely adopted method for broading the range of properties. In this work a new polyoxometalate constructed from Anderson-type polyoxoanions and L-arginine (Arg = L-arginine) molecules Na [CrMo6(OH)6O18]}(H2Arg)2·8H2O(1) has been synthesized via conventional method and characterized by routine techniques. Single-crystal X-Ray diffraction analysis shows that compound 1 is constructed by chiral L-arginine grafted Anderson-type clusters, sodium cation and water molecules which are further stabilized by hydrogen bonding interactions constitute 3D supramolecular networks. In addition, both antitumor behavior and photocatalytic activities of compound 1 were investigated.
Use of Graphene Oxide as a Bitumen Modifier: An Innovative Process Optimization Study
Authors: Habib Noor Zainab , Aun Ng Choon , Zoorob Salah E. , Lee Pei Ing
Published: May 2015

Graphene because of its higher surface area, strength, thinness and high electric conductivity has diversified uses from mechanical, electrical to bio medical engineering. This paper presents an initial study on modifying 80/100 penetration grade bitumen with Graphite oxide (GO) prepared by using Simplified Room Temperature Hummer’s process. The concept of utilizing GO for modification is adopted in order to improve the stiffness of the binder which can be helpful in reducing rutting potential of the pavement and to have electro thermal conductivity in modified binder, thus can be used during pavement remediation work. The limited trial rheological results obtained for 0.1125 wt. % GO modified bitumen and 0.225 wt. % GO modified bitumen showed that modification of bitumen with GO has improved its elastic capacity at higher temperature and lower frequency regime thus successfully can be used as bitumen modifier in future.
Notcheffect on J and Amplification of Anisotropic Stress Concentration Factor in a Laminated Plate Subjected to Tensile Load
Authors: Ouinas Djamel , Bachir Bouiadjra Bel Abbès , Albedah A. , Sahnoun Mohamed
Published: May 2015

Several analytical, numerical and experimental techniques are available to study the stress concentration around the notches. The stress distribution in a rectangular composite laminated plate with a central notch was studied using the finite element method. The objective of this study is to analyze the fibre orientation effect on the variation of stress concentrations at the notch root and the J-integral at the crack-tip emanating from this notch in a plate subjected to tensile loading. The results show that the anisotropic stress concentration factor can be higher or lower than that of a homogeneous material. The area of maximum normal and tangential stresses could shift with fibre orientation with respect to the loading axis. The interaction effect between a crack located on the ligament of the plate and the circular notch of radius is considered.The results indicate that fold sequence influences appreciably the acceleration or the retardation of the crack propagation.
Evaluation of SEE on a 32-bit Microprocessor by Laser Test and Heavy Ion Test
Authors: Yu Chun Qing , Fan Long , Yue Suge , Ma Jian Hua , Zheng Hong Chao
Published: May 2015

In this paper the SEE (single event effects) of different parts of device were explored on a 32-bit microprocessor with a five-stage instruction pipeline by laser test and heavy ion test. The cross section curves for different function units were obtained and the comparison of the dates obtained from laser test and heavy ion tests was made. In addition, laser test under different scanning steps were made which indicate that when the scanning step length is in small steps which is considerably equivalent to the laser spot size, there is little change in the number of single event errors caused by each laser pulse. Wherever with the scanning step increasing, the number of single event errors caused by each laser pulse will be reduced. Experiment results suggest that there are differences between laser test and the heavy ion test but have a similar trend. The pulsed laser is an extremely powerful and low-cost technique for SEE testing and will provide invaluable information in characterizing SEE in integrate circuits.
A Comparison Study of Bonded Composite Repairs of Through-Wall Cracks in Pipes Subjected to Traction, Bending Moment and Internal Pressure
Authors: Benyahia F. , Albedah A. , Bachir Bouiadjra Bel Abbès , Belhouari M.
Published: May 2015

In this study, a finite element analysis of the crack repair with composite wrap of circumferential through cracks in pipes subjected to bending moment is presented. Also, the evaluation of the long-term performance of composite repair systems has been addressed. The stress intensity factor is utilized as a fracture criterion. Finally, an attempt was made to provide industry with an overview of the current state of the art in composite repair technology and how the integrity of pipeline systems is being restored using composite materials. The obtained results show that the presence of the bonded composite repair reduces significantly the stress intensity factor, which can improve the residual fatigue life of the pipe. However, the main disadvantage of the technique of bonded composite repair in pipe is the impossibility to bond double sided composite wrap in order to equilibrate the stress transfer between the internal and external crack tip
Polyethylene/Clay Nanocomposites Prepared in an Internal Mixer: Effect of Processing Variable on Mechanical Properties
Authors: Ujianto Onny , Jollands Margaret , Kao Nhol
Published: May 2015

Polymer/clay nanocomposites have been explored extensively over the last two decades. Many studies report nanocomposite properties. However, studies on the effect of processing conditions are still limited. This study evaluates the effect of rotor type, rotor rotation (rpm) and mixing time on mechanical properties of polyethylene organoclay composites. Samples were fabricated using two different rotors; roller and Banbury, in an internal batch mixer at various mixing conditions. The analysis shows that the Banbury rotor improved mechanical properties more than the roller rotor. Shear and diffusion mechanism, as well as material degradation, were the controlling factors at different processing conditions.
Fabrication and Characterization of Biocomposite Using Grewia Optiva Fibre (i.e. Bhimal) Reinforced Polyvinyl Alcohol (PVA)
Authors: Gupta K.M. , Kalauni Kishor
Published: May 2015

Bhimal fibres are quite a newer kind of bio-degradable fibres. They have never been heard before in literatures from the view point of their utility as engineering material. These fibres have been utilized for investigation of their properties. Characterization of this fibre is essential to determine its properties for further use as reinforcing fibre in polymeric, bio-degradable and other kinds of matrix. With this objective, the fabrication method and other mechanical properties of Bhimal-reinforced-PVA biocomposite have been discussed. The stress-strain curves and load-deflection characteristics are obtained. The tensile, compressive, flexure and impact strengths have been calculated. The results are shown in tables and graphs. The results obtained are compared with other existing natural fibre biocomposites. From the observations, it has been concluded that the tensile strength of Bhimal-reinforced-PVA biocomposite is higher than other natural fibre composites. Hence these can be used as reinforcement to produce much lighter weight biocomposites.
Effect of Bentonite and Zinc Borate (ZB) Addition on Recycled Polypropylene Composites against Tensile and Burning Rate Properties
Authors: Sri Suharty Neng , Ismail Hanafi , Rakhman Wibowo Fajar , Suci Handayani Desi , Firdaus Maulidan , Lathifah Lupi
Published: May 2015

Has successfully created an optimum composite of rPP/DVB/PP-AA/comBen+ZB based on the mechanical and fuel resistance properties. The starting material recycled PP (rPP), PP modified acrylic acid (AA) as coupling agent (PP-AA), crosslinker divinylbenzene (DVB), 20 phr of commercial bentonite (comBen) and 5 phr of zinc borate (ZB), was reactivelly processed in xylene. Composites analysis using XRD presented that the bentonite had been exfoliated inside of PP matrix. Test results showed that both of tensile strength (TS) and young's modulus (YM) of rPP/DVB/PP-AA/comBen+ZB composites following ASTM D638 was increased. The testing results of burning rate (BR) of composite rPP/DVB/PP-AA/comBen+ZB according to ASTM D635 decreased. The presence of bentonite as a natural fire retardant and ZB as fire retardant additive on composite rPP/DVB/PP-AA/comBen+ZB able to increase mechanical properties and also improving the flammability resistance.
Utilization of Light Microscopy for the Evaluation of Fracture Toughness of Cemented Carbides
Authors: Špirit Zbyněk , Kříž Antonín
Published: May 2015

Cemented carbides belong among materials with high hardness and wear resistance even at temperatures around 700 °C. These properties are due to carbide composite structure which is formed mainly of tungsten carbide (WC) in combination with a metal matrix (usually cobalt). A synergistic effect that has a positive impact on the final properties is obtained by the combination of hard carbides and a soft matrix. The high hardness of the cemented carbides is associated with a decrease in fracture toughness which in the case of cutting tools is an important property. It is therefore necessary to measure the value of fracture toughness and thus monitor the state of the material. In practice, the fracture toughness of cemented carbides is usually tested by indentation methods of metallographic samples. Therefore, this work focuses on the comparison and optimization of computational models for determining fracture toughness using indentation methods. Eight types of cemented carbides used for the manufacture of cutting tools were tested. Fracture toughness of selected cemented carbides was measured after heat loading.
Influence of Heat Treatment Conditions on Properties of High-Speed P/M Steel Vanadis 30
Authors: Sobotová Jana , Kuřík Martin , Cejp Jiří
Published: May 2015

The high-speed P/M steel Vanadis 30 was austenitized at 1100 °C, quenched and tempered at various combinations of processing parameters. For one set of specimens, also sub-zero period, made at -196 °C/4 hours between quenching and tempering. The microstructure and mechanical properties have been investigated as a function of austenitizing time, parameters of sub-zero processing and tempering. There were used metallographic analysis, hardness measurement and three point bending test for the evaluation effect of heat treatment conditions to observed materials.
Assessment of the Causes of Indicated Defects in Forgings
Authors: Švejcar Jiří , Klakurková Lenka , Stránský Karel , Spotz Zdeněk , Čelko Ladislav
Published: May 2015

The article deals with analysis of defects indicated in large forgings in the course of ultrasonic testing. The aim of the metallographic analysis of the defects was to establish whether and to what extent casting or filling powders took part in their emergence that had been used when casting the ingots from which the forgings were made.
Defects in Tool Steels for Dies
Authors: Míšková Jana , Martínek Petr , Podaný Pavel
Published: May 2015

Selecting and correctly heat treating an appropriate tool steel for production a die is not a simple task. This paper points out defects which are encountered most frequently in dies when a poor-quality material or an inadequate heat treating schedule was selected or when the prescribed heat treating schedule was not followed. The most common deficiencies in semi-finished products from tool steels for die making include carbide banding and non-uniform microstructure with substantial variance in grain size. Incorrect tempering parameters are often used and the materials are thus treated in the region of temper brittleness. Cases of the above kind have been investigated by the laboratory at COMTES FHT a.s. in recent years and their summary is given in the text below.
Microstructure of Tool Steel X37CrMoV5 after Cryogenic Treatment and its Effect on Wear Resistance
Authors: Jandová Dagmar , Šuchmann Pavel , Nižňanská Jana
Published: May 2015

A deep cryogenic heat treatment (DCT) was applied to X37CrMoV5 steel, which included soaking at -160°C for 12 and 30 hours followed by tempering at 180°C. Microstructures were compared with those after conventional heat treatment (HT). Microstructures with conspicuous dendritic segregation were observed in all specimens. After HT coarser and finer tempered martensite occurred in depleted and enriched areas of carbon and alloying elements respectively. Coarse molybdenum and vanadium carbides, fine secondary Fe2MoC carbides and retained austenite were identified after HT. Deep freezing resulted in microstructure refinement, transformation of retained austenite into twinned martensite, spinodal decomposition of martensite plates and precipitation of semicoherent h-carbide. The mechanism of h-carbide precipitation was discussed. Wear rate was measured using pin-on-disc test. The best results were obtained after DCT with cryosoaking for 12 hours.
Detection of Cracks in the Production of Shafts
Authors: Holec Jan , Morávek Martin , Cejp Jiří
Published: May 2015

Safe operation of the machinery depends on quality of the individual machine parts. These are controlled by different non-destructive methods not only at the end of the production but also during it. In large quantity series production it is necessary to ensure the fastest control method possible. Shafts may bend during production due to the heat treatment and they need to be straightened by mechanical methods. Shafts straightening may cause cracks formation which is unacceptable from the point of view of the part operation. Therefore crack detection system QASS CiS.01 is used to reveal them on the basis of the magnitude of energy response. The results obtained from the detector were controlled using metallography and its function was successfully confirmed. It is not possible to determine relation between energy value and cracks length from carried out metallographic observation and values measured by the detector.
Novel Trends in the Development of Metallic Materials for Medical Implants
Authors: Vojtěch Dalibor , Kubásek Jiří , Čapek Jaroslav , Pospíšilová Iva
Published: May 2015

Metallic biomaterials are currently used in medicine for fabrication of various kinds of implants like joint and bone replacements, dental implants, stents, fixation devices for fractured bones etc. Their advantages over polymeric or ceramic biomaterials are in higher strength, fracture toughness and fatigue life. In addition, metals can be simply processed by established technologies known for centuries. Due to the increasing average age of human population, there are growing requirements for mechanical and functional performance of implants. Therefore, extensive research and development activities are focused on new directions in this area including new surface treatments and alloys with improved biocompatibility and mechanical performance, porous biomaterials, biodegradable metallic materials. Biodegradable materials are explored as alternatives for fabrication of temporary medical implants like stents and fixation devices (screws, plates, nails) for fractured bones. The present paper focuses on new Mg-and Zn-biodegradable alloys. Advantages of these materials are characterized with respect to mechanical performance and corrosion behavior.
Effect of Al Content and Heat Treatment on Microstructure of ZnAlCu Alloys
Authors: Longauerová Margita , Glogovský Miroslav , Vojtko Marek
Published: May 2015

The work analyses microstructures of ZnAl4Cu1, ZnAl27Cu2 and ZnAl40Cu2Si2 alloys in cast condition and after heat treatment in relation to microhardness HV0.2 and purity of the alloys. As shown the microstructure of ZnAl4Cu1 alloy contained η phase and eutectoid, which consisted phases α + η. ZnAl27Cu2 alloy contained α phase, eutectoid and ε phase, and ZnAl40Cu2Si2 alloy had a similar composition, but moreover contained Si particles. Microhardness in the molten state in ZnAl4Cu1 alloy was HV0.2 = 94, in ZnAl27Cu2 alloy it was HV0.2 = 117, and in ZnAl40Cu2Si2 alloy it was HV0.2 = 142.
Identification of Carbides in Sub-Zero Treated Vanadis 6 Ledeburitic Steel
Authors: Ptačinová Jana , Dománková Mária , Hudáková Mária , Jurči Peter , Bílek Pavel
Published: May 2015

Sub-zero processing is an add-on step of heat treatment that includes cooling down, holding at low temperature and re-heating up to room temperature. The aim of this process is to improve some mechanical properties of high-carbon steels. In this research, the Cr-V ledeburitic steel Vanadis 6 produced by powder metallurgy was used. As-received material as well as that after heat treatment contains various types of carbides, which are different in terms of both the nature and the origin. During the austenitizing, a part of the carbides (eutectoid, secondary) undergo dissolution in the austenite while other carbides (eutectic, secondary) remain in the material undissolved. The application of sub-zero treatment leads to increase in the volume fraction of small globular carbides, with a size below 0.3 μm. The volume fraction of secondary carbides was found to be constant, irrespectively to the use of sub-zero processing, but it decreases with increase of the austenitizing temperature. The nature of the carbides was found to be practically unaffected by the sub-zero treatment and it can be described as follows: The eutectic carbides are the vanadium rich MC-phase and the secondary ones are the M7C3. Regarding the nature of small globular particles, their nature is not doubtless because the electron diffraction fixed them as alloyed cementite but the EDX analysis revealed very high chromium content in the particles.
Occurrence, detection, and quantification of economically important viruses in healthy and unhealthy honey bee (Hymenoptera: Apidae) colonies in Canada
Authors: Desai Suresh D. , Kumar Santosh , Currie Robert W.
Published: May 2015

The occurrence, quantification, and distribution patterns of deformed wing virus (DWV) and sacbrood virus (SBV), (family Iflaviridae); black queen cell virus (BQCV), Israeli acute paralysis virus (IAPV), Kashmir bee virus (KBV), and acute bee paralysis virus (ABPV) (family Dicistroviridae), and chronic bee paralysis virus (CBPV) (unclassified), were characterised in 80 “healthy” honey bee (Apis mellifera Linnaeus; Hymenoptera: Apidae) colonies and 23 “unhealthy” colonies by employing reverse transcription polymerase chain reaction (RT-PCR) for virus identification and quantitative real-time polymerase chain reaction (qPCR) for quantification. All seven viruses were common but the most prevalent viruses were DWV, followed by BQCV and IAPV. For most viruses, prevalence in surviving but unhealthy colonies in spring did not differ from that of healthy baseline colony levels in fall suggesting spring prevalence level would not be a useful metric for diagnosis of factors contributing to colony loss. Sacbrood virus was the only virus that was more prevalent in unhealthy colonies from Manitoba, Canada than in healthy from colonies across Canada but did not differ from healthy colonies within Manitoba. Multiple infections were ubiquitous with a few colonies having simultaneous infection with as many as five viruses. Among the three viruses quantified by qPCR, DWV had the highest relative concentrations in pooled samples of worker bees. Deformed wing virus was the only virus within healthy colonies that differed in fall concentration among provinces and was at high levels in unhealthy colonies. Black queen cell virus was positively correlated with IAPV across all samples. Our study provides the first major baseline study of viruses in Canadian honey bees.
Conflicting personalities and driving ambition
Authors: Potgieter Raymond
Published: May 2015

No abstract available
The 'cognitive' and the 'emotive' component in Christian songs: Tracing the shifts in traditional and contemporary songs
Authors: T�nsing J. Gertrud , Wepener Cas J. , Vos Cas
Published: May 2015

This research article is based on the author�s doctoral research into the question of quality criteria for Christian songs. In many Christian congregations today, the question of music is an emotive issue as the service and its music touch the heart of people�s faith life and shapes people�s theology. Of the many issues that were investigated in the dissertation, this article focuses on one question only, the question of the �cognitive� and the �emotive� value of the songs that are sung in a Sunday service. It will be argued that, in �good� songs, there needs to be a good balance between �cognitive� and �emotive� value. The general question is how to identify songs that can nurture faith and sustain people through life. Characteristic of such songs is, amongst many other criteria, a good balance between the cognitive and emotive value of the text and the tune. In the discussion, the author focusses largely on her own Lutheran liturgical and hymnological tradition as well as on the �Praise and Worship� movement which has a dramatic impact on churches all over the world. The author argues that finding songs that balance the emotive and the cognitive component is an effective way to bridge the divides on worship music within a congregation.Intradisciplinary and/or interdisciplinary implications: Within the discipline of hymnological studies, the article opens a ground-breaking new way to analyse and critique music used in worship with objective tools for analysis. This is, as far as the author knows, new for this discipline, and it also has an effect on other disciplines.
Determining Factors of Transparency and Accountability in Local Governments: A Meta-Analytic Study
Authors: Alcaide-Muñoz Laura , Rodríguez Bolívar Manuel Pedro
Published: May 2015

The importance granted to information transparency in improving the accountability of public administrations has become increasingly greater in recent years under a scenario of economic and financial crisis as a tool of control. Although academic studies are aimed at identifying the key factors underlying a higher level of economic-financial information disclosure by local governments, there exists considerable heterogeneity in the results obtained. In this sense, we have carried out a meta-analysis to validate previous empirical results, and highlight causes of the variations and contradictions identified. Our study shows the variables analysed to be positively associated with the disclosure of public financial information, but also that this depends on the context in which the research is carried out.
Drivers for the financial condition of Local Government: a comparative study between Italy and Spain
Authors: Brusca Isabel , Manes Rossi Francesca , Aversano Natalia
Published: May 2015

This paper aims to analyse the influence of socio-economic, political and financial factors on the financial condition of Italian and Spanish local governments in a comparative approach. The research is also aimed at understanding to what extent a model for the analysis of the financial condition can be generalized to different contexts. We assume that the financial condition is a multidimensional concept, with the results highlighting that while in Spain there is a high correlation between the long term financial and short term economic situations and an indicator can combine both dimensions, in Italy both dimensions are differentiated. There are also differences in the drivers of financial sustainability in both countries.
Evaluation of Municipalities Management with the Topsis Technique Emphasising on the Impact of Weights of Established Criteria
Authors: Vavrek Roman , Kotulic Rastislav , Adamisin Peter
Published: May 2015

In Slovakia the management of municipalities is governed by law, which considers indebtedness of a municipality to be the main and the only criterion. The aim of the presented paper is to offer an alternative to the legal view of municipal finances assessment. The paper defines TOPSIS technique as possibly suitable alternative for comprehensive evaluation of municipalities management. This technique is applied to a set of municipalities in Presov self-governing region at two levels – at the same and adjusted weights of monitored indicators. The aim of this paper is to establish the order of municipalities with the best management according to selected criteria. The application results are statistically investigated further because of identifying of weight indicators impact as well as identification of observed correlations.
Validation of a Crowdsourcing Methodology for Developing a Knowledge Base of Related Problem-Medication Pairs
Authors: Wright A. , Krousel-Wood M. , Thomas E. J. , McCoy J. A. , Sittig D. F. , McCoy A. B.
Published: May 2015

Background: Clinical knowledge bases of problem-medication pairs are necessary for many informatics solutions that improve patient safety, such as clinical summarization. However, developing these knowledge bases can be challenging.

Objective: We sought to validate a previously developed crowdsourcing approach for generating a knowledge base of problem-medication pairs in a large, non-university health care system with a widely used, commercially available electronic health record.

Methods: We first retrieved medications and problems entered in the electronic health record by clinicians during routine care during a six month study period. Following the previously published approach, we calculated the link frequency and link ratio for each pair then identified a threshold cutoff for estimated problem-medication pair appropriateness through clinician review; problem-medication pairs meeting the threshold were included in the resulting knowledge base. We selected 50 medications and their gold standard indications to compare the resulting knowledge base to the pilot knowledge base developed previously and determine its recall and precision.

Results: The resulting knowledge base contained 26,912 pairs, had a recall of 62.3% and a precision of 87.5%, and outperformed the pilot knowledge base containing 11,167 pairs from the previous study, which had a recall of 46.9% and a precision of 83.3%.

Conclusions: We validated the crowdsourcing approach for generating a knowledge base of problem-medication pairs in a large non-university health care system with a widely used, commercially available electronic health record, indicating that the approach may be generalizable across health-care settings and clinical systems. Further research is necessary to better evaluate the knowledge, to compare crowdsourcing with other approaches, and to evaluate if incorporating the knowledge into electronic health records improves patient outcomes.

Citation: McCoy AB, Wright A, Krousel-Wood M, Thomas EJ, McCoy JA, Sittig DF. Validation of a crowdsourcing methodology for developing a knowledge base of related problem-medication pairs. Appl Clin Inf 2015; 6: 334–344

http://dx.doi.org/10.4338/ACI-2015-01-RA-0010
Patient Preferences in Selecting a Dentist: Survey Results from the Urban Population of Riyadh, Saudi Arabia
Authors: Sukumaran Anil , Vellappally Sajith , Huraib Sahar Bin , Nahas Nadia Al , Al-Balbeesi Hana O , Abu-Aljadayl Faida Moawia
Published: May 2015

Introduction

Awareness of gender- or nationality-driven preconceptions can help dentists to have a better interpretation of the dentist-patient relationship. It is even more noteworthy to understand these predilections in Saudi society, where women and men are usually segregated due to religion- and culturebased considerations. This study is one of the first to explore the preferences of patients when selecting a dentist with respect to gender and nationality in the city of Riyadh, Saudi Arabia.

Materials and methods

A total of 445 community residents residing in Riyadh were randomly selected for a cross-sectional study. The participants completed a survey designed to assess which of two factors (gender and/or nationality) were perceived as most relevant in choosing a dentist. Statistical analysis of the data was performed using the SPSS 11.5 software.

Results

Female participants did not show any preference for the gender of the dentist, whereas 40% of the male participants preferred a male dentist. Participants also favored male dentists in the fields of oral surgery (78.9%), implants (74.1%), endodontics (67.5%), orthodontics (65.8%) and prosthodontics (64.2%). An exception was noted in pediatric dentistry, for which female dentists were favored by 52.8% of the participants. Additionally, most (66.1%) participants did not have any preference for the nationality of the dentist.

Conclusion

Riyadh residents showed a general preference for a male dentist but demonstrated no preference for nationality when selecting a dentist.

How to cite this article

Huraib SB, Al Nahas N, Al-Balbeesi HO, Abu-Aljadayl FM, Vellappally S, Sukumaran A. Patient Preferences in Selecting a Dentist: Survey Results from the Urban Population of Riyadh, Saudi Arabia. J Contemp Dent Pract 2015;16(3): 201-204.
Mandibular Coronoid Fractures, How Rare?
Authors: Kale Tejraj Pundalik , Kotrashetti SM , Lingaraj JB , Aggarwal Vipin
Published: May 2015

Background

To study the rarity of mandibular coronoid process fractures and treatment strategies based on the displacement of these fractures.

Materials and methods

A retrospective study of 11 cases of coronoid process fractures among 307 treated cases from 2008 to 2013 was conducted. Six patients were treated conservatively and 5 underwent ORIF with associated fractures. A statistical analysis of the data obtained after subjective and objective evaluation was done.

Results

The incidence of coronoid process fractures was 3.58% of all mandibular fractures analyzed. There was no statistically significant difference found between two treatment modalities, but differences in maximum interincisal opening (MIO) and pain in the postoperative period were significant.

Conclusion

We recommend that linear coronoid fractures with minimal displacement can be managed with conservative treatment. For patients with significant displacement of coronoid process, limited mouth opening or concomitant mid-face or lower-face fractures, rigid internal fixation is recommended.

How to cite this article

Kale TP, Aggarwal V, Kotrashetti SM, Lingaraj JB, Singh A. Mandibular Coronoid Fractures, How Rare? J Contemp Dent Pract 2015;16(3):222-226.
Occurrence of Domestic Violence among Women and its Impact on Oral Health in Jodhpur City
Authors: Thomas Susan , Pewa Preksha , Dagli Rushabh , Solanki Jitendra , Arora Geetika , Garla Bharath
Published: May 2015

Background

This study had a two objectives to determine the prevalence of domestic violence and to know the impact of the same on the oral health.

Materials and methods

An observational cross-sectional study was done in Jodhpur, Rajasthan; among 150 married women of 18 to 60 years of age using a predesigned pretested proforma from 18th January 2014 to 27th February 2014. Pretested semistructured open-ended questionnaire used for collecting the data from the study subjects. Pearson's Chisquare test and p-value were used to calculated the occurrence and impact of domestic violence on oral health among women.

Results

The most common form of domestic violence found was physical abuse (54.7%) followed by emotional abuse (20.0%) and financial abuse (14.0%). The most important risk factor was alcoholism followed by literacy status and having a girl child. Study shows that physical abuse is more in graduate than lower level of educational females. Females living in urban area show highest frequency of physical abuse than those living in rural area. Injury to the face were highly reported (38.7%) followed by injury to lip (13.3%) and nose fracture/bleeding nose (9.3%).

Conclusion

Government has to take stringent action to prevent domestic violence by making women more self-reliant especially by making women more literate and more financially independent.

How to cite this article

Pewa P, Thomas S, Dagli R, Solanki J, Arora G, Garla B. Occurrence of Domestic Violence among Women and its Impact on Oral Health in Jodhpur City. J Contemp Dent Pract 2015;16(3):227-233.