bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Material Model of the Polyurethane Elastomer on the FEM Calculations Quality for the Various Modes of Loading
Authors: Kut S. , Ryzińska G. , Niedziałek B.
Published: July 2017

The paper presents research to verify the effectiveness of nine selected material models of elastomeric materials based on uniaxial tension test. Basing on the cyclic uniaxial tension test of elastomers sample, the stress-strain characteristic for the 18th load cycle was prepared. On the basis of the obtained characteristic, the values of material constants were calculated for the studied models (Neo-Hookean, Mooney with two and three constants, Signorini, Yeoh, Ogden, Arruda-Boyce, Gent and Marlow) and simulation of tensile, upsetting and bending processes was performed with the usage of the software MARC/Mentat. The effectiveness of the selected models was determined based on a comparison of results obtained in the experimental tensile test, upsetting test and bending test of an elastomeric samples with the results of numerical FEM calculations for each models. The research has shown that, for modeling of the elastomeric cylinder upsetting in the range of deformation of 62%, the best results with the comparison of the experiment were obtained by using the Yeoh model. In the bending process none of the analyzed models indicate a high convergence of results from an experiment. Analyzing the characteristics of the experimental and numerical tensile test it can be seen that in the entire range of punch movement (0 to 55 mm), models Signorini, Marlow, Ogden(N3) and Mooney(3) give the best results.
Quantitative Evaluation of the Microstructure and Mechanical Properties of Hot Rolled 23MnB4 Steel Grade for Cold Upsetting
Authors: Kuc D. , Szala J. , Bednarczyk I.
Published: July 2017

The article presents the results of tests of influence of the thermo-mechanical treatment parameters on the mechanical properties and microstructure of steel 23MnB4 for cold-upsetting. Measurements of the ferrite grains and pearlite colonies were conducted with the use of Met-Ilo program supplemented by additional procedures dedicated to structure analysis of ferritic-pearlitic steel. The process of rolling was conducted in simulation in semi-continuous finishing train arrangement with different temperature and cooling rate. Elaborated procedure of quantitative analysis of microstructure and conducted mechanical properties tests will be used during preparations of modified technologies of wire rod rolling to prepare products made of steel, the microstructure of which is characterised higher utility properties.
Numerical Modelling of Micro-Stresses in Carbonised Austenitic Cast Steel under Rapid Cooling Conditions
Authors: Tuleja J. , Zatorski Z.
Published: July 2017

The paper presents a method of the numerical modelling of micro-stresses in carbonised austenitic cast steel being developed during rapid cooling due to differences in the values of thermal expansion coefficients for this material phases – carbides and austenitic matrix. Micro-stresses are indicated as the main cause of crack initiation in the tooling elements of carburising furnaces being mainly made of austenitic cast steel. A calculation model of carbonised and thermally fatigued austenitic cast steel was developed based on the microstructure images obtained using light microscopy techniques and the phase composition evaluated with the X-ray diffraction method. The values of the stress tensor components and the reduced stress in the complex models of test material structure were determined numerically by the finite element method. The effort analysis was performed and the areas where development of cracks is to be expected were identified, which was experimentally confirmed.
Effect of the Austempering Process on the Microstructure and Mechanical Properties of 27MnCrB5-2 Steel
Authors: Morri A. , Ceschini L. , Pellizzari M. , Menapace C. , Vettore F. , Veneri E.
Published: July 2017

The effect of austempering parameters on the microstructure and mechanical properties of 27MnCrB5-2 steel has been investigated by means of: dilatometric, microstructural and fractographic analyses; tensile and Charpy V-notch (CVN) impact tests at room temperature and a low temperature.

Microstructural analyses showed that upper bainite developed at a higher austempering temperature, while a mixed bainitic-martensitic microstructure formed at lower temperatures, with a different amount of bainite and martensite and a different size of bainite sheaf depending on the temperature. Tensile tests highlighted superior yield and tensile strengths (≈30%) for the mixed microstructure, with respect to both fully bainitic and Q&T microstructures, with only a low reduction in elongation to failure (≈10%). Impact tests confirmed that mixed microstructures have higher impact properties, at both room temperature and a low temperature.
Nickel in Compacted Graphite Iron
Authors: Gumienny G. , Kurowska B. , Szymczak T. , Gawroński J.
Published: July 2017

The paper presents results of the research work concerning effects of nickel concentration on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in the cast iron was obtained with use of the Inmold process. The study has comprised the cast iron containing nickel up to concentration providing obtainment of austenitic microstructure of the matrix. The effect of the nickel on temperature of the eutectic crystallization was specified. It has been presented composition of the cast iron matrix in function of nickel concentration in a casting with wall thickness of 3 mm and 24 mm. Moreover, it has been presented conditions defining the possibility of obtaining an austenitic and martensitic compacted graphite iron. Effect of the nickel on hardness of the cast iron was described.
Structural Properties and Mechanical Behavior of the 2 Step-Reinforced Al-Si/SiCp Metal Matrix Composite by Titanium-Fiber
Authors: Oak J.J. , Lee Y.C. , Park Y.H.
Published: July 2017

In this study, the newly designed Al-9Si/SiC particles (SiCp) + Ti-fiber (2step-reinforced Al-9Si alloy matrix) metal matrix composites (MMCs) were fabricated by hot-pressing sintering at 560°C. 2step-reinforced Al-based MMCs were characterized by thermal shrinkage, phase transition, microstructure and tensile strength. The addition of Ti-fiber reduced thermal shrinkage was caused by temperature difference in sintering process as well as enhanced assistance for tensile strength and plastic deformation at room temperature. Experimental results reveal that the 2step-reinforcment sintering by ceramic and metal has a significant effect to increase interface bonding in boundary of each component material and the improved mechanical properties were due to the influence of interfacial product by diffusion. Tensile strength and elongation at room temperature by 2step-reinforcement were improved in 19.5% and 26.2% more than those of Al-9Si/SiCp, respectively. Especially, it reveals that diffusion direction may be varied by sintering methods at low temperature in this study.
Preparation and Properties of Ti-Y2O3 Composites for Implant Applications
Authors: Adamek G. , Jakubowicz J. , Dewidar M.
Published: July 2017

The paper presents the preparation of Ti-(1-30wt.%)Y2O3composites using the mechanical alloying process. Ti based materials are the best metallic biomaterials because of their excellent properties: biocompatibility, low Young moduli and high corrosion resistance. Pure Ti and Y2O3powders were alloyed under argon atmosphere in shaker type mill (Spex 8000) followed by pressing and sintering.

The ultra-low grain size structure improves the mechanical properties and hardness of the new materials in comparison to microcrystalline Ti-based sinters. However, because of the porosity of approx. 20-30%, a decrease in the Young modulus is observed. Moreover, the new composites show good tendency towards covering by Ca-P compounds during soaking in SBF.
The Influence of Synthesis Temperature on Manufacturing and Properties of SrSi2O2N2:Eu2+ Powders
Authors: Pawlik T. , Michalik D. , Barzowska J. , Szczodrowski K. , Lesniewski T. , Sopicka-Lizer M. , Grinberg M.
Published: July 2017

This paper presents the results of the synthesis temperature on the properties of the ceramic powders of SrSi2O2N2:Eu2+ obtained by the solid-phase reaction. Synthesis was carried out in the temperature range of 1250-1650°C for 2 hours in nitrogen flow in the reducing atmosphere of the graphite furnace. The phases present in the resultant powders were identified by X-ray structural analysis (XRD). Scanning electron microscopy (SEM) was used to examine the changes in the powder morphology as a result of the synthesis. The excitation and emission spectra measurements let to study phosphor photoluminescence properties. The results show the strong influence of temperature synthesis on the formation and purity of expected phases. The synthesis temperature also affects the luminescent properties of SrSi2O2N2:Eu2+ ceramic powders.
Microstructure Characterization of SiC Reinforced Aluminium and Al4Cu Alloy Matrix Composites
Authors: Leszczyńska-Madej B. , Wąsik A. , Madej M.
Published: July 2017

A conventional powder metallurgy method (PM) was used to produce Al-SiC and Al4Cu alloy matrix composites with 2.5, 5, 7.5 and 10 wt% of SiC particles. Two different sizes of the reinforcing phase particles were applied to determine their effect on composite microstructure. The sintering process was carried out at 600°C under nitrogen atmosphere, and its consequence was the appearance of aluminium nitrides in composite microstructure acting as an additional strengthening phase. The composites were next re-pressed and re-sintered (2p2s) under the same conditions. The main aim of this article was to examine the microstructure of the SiC reinforced Al and Al4Cu alloy matrix composites. To achieve this goal and characterize the sintered materials, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were used.
Brazing of Titanium with Aluminium Alloys
Authors: Winiowski A. , Majewski D.
Published: July 2017

This study presents results of vacuum diffusion brazing of Grade 2 titanium with 6082 (AlMg1Si0.6Cu0.3) aluminium alloy using B-Ag72Cu-780 (Ag72Cu28) grade silver brazing metal as an interlayer. Brazed joints underwent shear tests, light-microscopy-based metallographic examinations and structural examinations using scanning electron microscopy (SEM) and X-ray energy dispersive spectrometry (EDS). The highest quality and shear strength of 20 MPa was characteristic of joints brazed at 530°C with a 30-minute hold. The structural examinations revealed that in diffusion zone near the boundary with titanium the braze contained solid solutions based on hard and brittle Ti-Al type intermetallic phases determining the strength of the joints.
Mechanical and Microstructural Response of Near Beta Ti Alloys to Hot Tensile Testing
Authors: Abbasi S.M. , Momeni A. , Daraee M. , Akhondzadeh A. , Mirsaeed S.G.
Published: July 2017

Hot tensile tests were carried out on Timetal-125 and Timetal-LCB near beta Ti alloys at temperatures in range of 600-1000°C and constant strain rate of 0.1 s−1. At temperatures below 700-800°C, the homogenuous and total strains for Timetal-LCB were greater than those for Timetal-125. In contrast, at temperatures over 800°C, Timetal-125 showed better hot ductility. The yield point phenomena was observed in Timetal-LCB at all temperatures. Unlikely, for Timetal-125, it was observed only at temperatures over 800°C. The weaker yield point phenomena in Timetal-125 could be attributed to the negative effect of Al on the diffusion of V. At all temperatures Timetal-LCB exhibited higher strength than Timetal-125. It was found that there should be a direct relationship between the extent of yield point phenomena and strength and dynamic softening through hot tensile testing. It was observed that at temperatures beyond 800°C (beta phase field in both alloys) dynamic recrystallization can progress more in Timetal-125 than in Timetal-LCB. These results were in good agreement with the better hot ductility of Timetal-125 at high temperatures. At low temperatures, i.e. below 700-800°C, partial dynamic recrystallization occurs in beta and dynamic globularization in alpha phase. These processes progress more in Timetal-LCB than in Timetal-125.
Combined Effects of Copper and Tin at Intermediate Level of Manganese on the Structure and Properties of As-Cast Nodular Graphite Cast Iron
Authors: Lacaze J. , Sertucha J. , Larrañaga P. , Suárez R.
Published: July 2017

Copper, manganese and tin are commonly used as pearlite promoter elements in cast irons. A number of studies have been aimed at quantitatively evaluate the effect of each of these elements, individually or at given levels of the others. As a matter of fact, while tin may be necessary for achieving a fully pearlitic matrix, it is known that when in excess it is detrimental for mechanical properties. As the pearlite promoting effect of each of those elements is totally different, it is of real interest to know the optimum combination of them for a given cooling rate. The present report is a first part of a work dedicated at characterizing the best alloying levels in terms of room temperature mechanical properties of as-cast pearlitic materials.
Photosensitization of TiO2 P25 with CdS Nanoparticles for Photocatalytic Applications
Authors: Trenczek-Zając A. , Banaś J. , Świerczek K. , Zazakowny K. , Radecka M.
Published: July 2017

A TiO2/CdS coupled system was prepared by mixing the TiO2P25 with CdS synthesized by means of the precipitation method. It was found that the specific surface area (SSA) of both components is extremely different and equals 49.5 for TiO2and 145.4 m2·g−1for CdS. The comparison of particle size distribution and images obtained by means of transmission electron microscopy (TEM) showed agglomeration of nanocomposites. X-ray diffraction (XRD) patterns suggest that CdS crystallizes in a mixture of cubic and hexagonal phases. Optical reflectance spectra revealed a gradual shift of the fundamental absorption edge towards longer wavelengths with increasing CdS molar fraction, which indicates an extension of the absorption spectrum of TiO2. The photocatalytic activity in UV and UV-vis was tested with the use of methyl orange (MO). The Langmuir–Hinshelwood model described well the photodegradation process of MO. The results showed that the photocatalytic behaviour of the TiO2/CdS mixture is significantly better than that of pure nanopowders.
Collosion and Absorption Behaviors of Inclusions on Refractory
Authors: Ding-Guo Z. , Ming G. , Xin L. , Shu-Huan W.
Published: July 2017

The paper is dedicated to analysis the inclusion behavior in steel using theoretical calculation and simulation of water. The aim is to establish collision and absorption model of inclusions on refractory. The article discusses the variation of critical stay speed and critical shear with the radius of inclusions in the process of colliding, rebounding and absorbing. The results show the critical stay speed and critical shear of alumina respectively surpasses 1 cm·s−1and 1 N·m−2, while titanium dioxide separately exceeds 4 cm·s−1and 10 N·m−2for the inclusions that radius is less than 2.5 μm. If the inclusions occur rebound after colliding, the inclusions that radius is less than 7 μm will still be absorbed by the surface, while the inclusions that radius is more than 10 μm can easily reenter the steel. The model coincides with the water simulation results and it is of good adaptability.
A Simplified Approach for the Hydro-Forming Process of Bi-Metallic Composite Pipe
Authors: Zheng M. , Gao H. , Teng H. , Hu J. , Tian Z. , Zhao Y.
Published: July 2017

In this article, it aims to propose effective approaches for hydro-forming process of bi-metallic composite pipe by assuming plane strain and elastic-perfectly plastic material model. It derives expressions for predicting hydro-forming pressure and residual stress of the forming process of bi-metallic composite pipe. Test data from available experiments is employed to check the model and formulas. It shows the reliability of the proposed model and formulas impersonally.
An Evaluation of the Stability of Mould Flux Properties in the Process of Continuous Steel Casting
Authors: Falkus J.
Published: July 2017

This paper presents research on the mould slag formed on the basis of two mould fluxes. In the conducted industrial experiments, slag was sampled in equal time intervals between adding subsequent portions of mould flux. The research focused on the an evaluation of the stability of slag parameters by assessing the change in its liquidus temperature. It was shown that a mould flux needs to be assessed individually taking into account the casting process parameters and the steel cast grade.
Application of High Flow Rate Gas in the Process of Argon Blowing Trough Steel
Authors: Merder T. , Pieprzyca J. , Warzecha M. , Warzecha P.
Published: July 2017

The article demonstrates results of modelling research tests concerning the analysis of possibilities of blowing gas into the metal bath at high flow rates in a steel ladle with a nominal capacity of 50 Mg. Various configurations concerning of gas introduction into the steel ladle were analysed. There were considered cases of blowing into the metal bath via one, two or three purging plugs, being installed on the bottom and via additional support for blowing the gas from the top through the lance.

Results obtained from the water model of the reactor were verified with the results of numerical simulations.
Numerical and Physical Parametric Analysis of a SEN with Flow Conditioners in Slab Continuous Casting Mold
Authors: Gonzalez-Trejo J. , Real-Ramirez C.A. , Miranda-Tello R. , Rivera-Perez F. , Cervantes-de-la-Torre F.
Published: July 2017

Some of the most recent technologies that improves the performance in continuous casting process has installed infrastructure outside the mold to modify the natural fluid flow pattern to obtain a quasi-steady condition and promote a uniform solidified shell of steel. The submerged entry nozzle distributes the liquid steel in the mold and can be used to obtain the flow symmetry condition with external geometry improvements. The fluid flow conditioners were located near the outlet ports of the nozzle. The aim of the modifiers is to impose a pseudo symmetric pattern in the upper zone of the mold by inhibiting the fluid exchange between the zones created by conditioners. This work evaluates the effect of the thickness and length of the fluid-flow modifiers on the overall performance of the submerged nozzle. These properties of the fluid-flow modifiers were normalized based on two of the geometric dimensions of the standard equipment. Numerical and physical simulations suggest that the flow modifier should be as thin as possible.
Disruption of an Alumina Layer During Sintering of Aluminium in Nitrogen
Authors: Pieczonka T.
Published: July 2017

Aluminium oxide layer on aluminium particles cannot be avoided. However, to make the metal-metal contacts possible, this sintering barrier has to be overcome in some way, necessarily to form sintering necks and their development. It is postulated that the disruption of alumina layer under sintering conditions may originate physically and chemically. Additionally, to sinter successfully non alloyed aluminium powder in nitrogen, the operation of both types mechanism is required. It is to be noted that metallic aluminium surface has to be available to initiate reactions between aluminium and the sintering atmosphere, i.e. mechanical disruption of alumina film precedes the chemical reactions, and only then chemically induced mechanisms may develop. Dilatometry, gravimetric and differential thermal analyses, and microstructure investigations were used to study the sintering response of aluminium at 620°C in nitrogen, which is the only sintering atmosphere producing shrinkage.
The Effect of Additive Element on the Properties of Mechanically Alloyed Fe-Y2O3 Alloys
Authors: Ahn Jung-Ho , Kim Tae Kyu , Ahn Jeongsuk
Published: July 2017

In the present work, we have examined the effect of Ti on the properties of Fe-Y2O3 alloys. The result showed that the addition of Ti was effective for improving mechanical properties. This is due to the reduction of oxides by Ti during mechanical alloying and hot-consolidation. In particular, iron oxides are effectively reduced by the addition of Ti. Compared to the pristine Fe-Y2O3 alloys, titanium-added alloys exhibited fine and uniform microstructures, resulting in at least 60% higher tensile strength.
Fabrication of a Spherical Titanium Powder by Combined Combustion Synthesis and DC Plasma Treatment
Authors: Choi S.H. , Ali B. , Hyun S.K. , Sim J.J. , Choi W.J. , Joo W. , Lim J.H. , Lee Y.J. , Kim T.S. , Park K.T.
Published: July 2017

Combustion synthesis is capable of producing many types of refractory and ceramic materials, as well as metals, with a relatively lower cost and shorter time frame than other solid state synthetic techniques. TiO2with Mg as reductant were dry mixed and hand compacted into a 60 mm diameter mold and then combusted under an Ar atmosphere. Depending on the reaction parameters (Mg concentration 2 ≤α≤ 4), the thermocouples registered temperatures between 1160°C and 1710°C · 3 mol of Mg gave the optimum results with combustion temperature (Tc) and combustion velocity (Uc) values of 1372°C and 0.26 cm/s respectively. Furthermore, this ratio also had the lowest oxygen concentration in this study (0.8 wt%). After combustion, DC plasma treatment was carried out to spheroidize the Ti powder for use in 3D printing. The characterization of the final product was performed using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and N/O analysis.
Correlation Between Pin Misalignment and Crack Length in THT Solder Joints
Authors: Molnar A. , Benke M. , Gacsi Z.
Published: July 2017

In this manuscript, correlations were searched for between pin misalignments relative to PCB bores and crack propagation after cyclic thermal shock tests in THT solder joints produced from lead-free solder alloys. In total, 7 compositions were examined including SAC solders with varying Ag, Cu and Ni contents. The crack propagation was initiated by cyclic thermal shock tests with 40°C / +125°C temperature profiles. Pin misalignments relative to the bores were characterized with three attributes obtained from one section of the examined solder joints. Cracks typically originated at the solder/pin or solder/bore interfaces and propagated within the solder. It was shown that pin misalignments did not have an effect on crack propagation, thus, the solder joints’ lifetime.
Challenges of Using Elemental Nickel and Titanium Powders for the Fabrication of Monolithic NiTi Parts
Authors: Farvizi M.
Published: July 2017

Due to its interesting properties and wide applications in different industries, fabrication of monolithic NiTi with cost-effective methods is an important and attractive issue. One of the economic ways to fabricate NiTi is employing elemental nickel and titanium powders. In this study, effects of using elemental powders as a precursor on the microstructure and mechanical properties of HIP-consolidated NiTi samples will be explored. The result of XRD analysis showed that after HIP process an interwoven structure which consists of NiTi2, Ni3Ti and B2-B19′ NiTi evolves. The formation of NiTi2/Ni3Ti intermetallics is thermodynamically favored which affects different aspects of this alloy: (i) it alters martensitic transformation temperatures; (ii) restricts essential properties of this alloy such as PE and SME, (iii) increases hardness, and (iv) yields to premature fracture at small strains during tensile tests.
Microstructure and Mechanical Properties of Al-3 Vol% CNT Nanocomposites Processed by High-Pressure Torsion
Authors: Asgharzadeh H. , Kim H.S.
Published: July 2017

Al-3 vol% CNT nanocomposites were processed by high-pressure torsion (HPT) at room temperature under the pressure in the range of 2.5-10 GPa for up to 10 turns. Optical microscopy, scanning electron microscopy, and transmission electron microscopy (TEM) were used to investigate the microstructural evolutions upon HPT. Mechanical properties of the HPT-processed disks were studied using tensile tests and microhardness measurements. The results show gradual evolutions in the density, microstructure, and hardness with increasing the number of turns and applied presure. Nanostructured and elongated Al grains with an average grain thickness of ~40 nm perpendicular to the compression axis of HPT and an aspect ratio of ~3 are formed after 10 turns under 6 GPa. Evaluating the mechanical properties of the 10-turn processed Al/CNT nanocomposites indicates a tensile strength of 321 MPa and a hardness of 122 Hv. The tensile fracture surface of the Al/CNT nanocomposite mostly demonstrates a smooth fracture manner with fine dimples resulting in a low tensile ductility of ~1.5%.
Fabrication of High-Strength Gray Cast Iron Using Permanent Magnet Scrap
Authors: Park Seung-Yeon , Kim J.H. , Seo S.J. , On J.S. , Lim K.M.
Published: July 2017

In this study, we have developed the manufacturing technology for high strength gray cast irons by using the spent permanent magnet scraps. The cast specimen inoculated by using a spent magnet scraps showed the excellent tensile strength up to 306MPa. This tensile strength value is 50MPa higher than that of the specimen cast without inoculation, and is similar to that of the specimen inoculated by using the expensive misch-metal. These superior mechanical properties are attributed to complex sulfides created during solidification that promote the formation and growth of Type-A graphite. It is therefore concluded that spent magnets scrap can provide an efficient and cost-effective inoculation agent for the fabrication of high-performance gray cast iron.
Examination of Clustering in Eutectic Microstrcture
Authors: Bortnyik K. , Barkóczy P.
Published: July 2017

The eutectic microstructures are complex microstructures and a hard work to describe it with few numbers. The eutectics builds up eutectic cells. In the cells the phases are clustered. With the development of big databases the data mining also develops, and produces a lot of method to handling the large datasets, and earns information from the sets. One typical method is the clustering, which finds the groups in the datasets. In this article a partitioning and a hierarchical clustering is applied to eutectic structures to find the clusters. In the case of AlMn alloy the K-means algorithm work well, and find the eutectic cells. In the case of ductile cast iron the hierarchical clustering works better. With the combination of the partitioning and hierarchical clustering with the image transformation, an effective method is developed for clustering the objects in the microstructures.
Effect of Alloying Elements on Plastic Workability and Corrosion Behavior of Ti-X (X = 6 Co, 8 Cr, 4 Fe, 6 Mn, 10 Mo, and 36 Nb) Binary Alloys
Authors: Zhao Z. , Lee K.
Published: July 2017

The purpose of this study was to investigate the effect of the alloying elements on the plastic workability and corrosion behavior of Ti-X (wt.%) (X = 6 Co, 8 Cr, 4 Fe, 6 Mn, 10 Mo, and 36 Nb) binary alloys. The alloys with a molybdenum equivalence of 10 wt.% were fabricated by a vacuum arc re-melting process and were then homogenized at a temperature 20°C greater than the beta transus temperature for 14.4 ks. The plastic workability was investigated under uniaxial cold rolling, while the corrosion behavior was examined in Ringer’s solution at 37°C. Among the Ti-X alloys, the Ti-8 wt.% Cr and Ti-6 wt.% Mn alloys showed an outstanding plastic workability and corrosion resistance, respectively.
Compressive Deformation Behavior of Thick Micro-Alloyed HSLA Steel Plates at Elevated Temperatures
Authors: Lee J.-H. , Kim D.-O. , Lee K.
Published: July 2017

The hot deformation behavior of a heavy micro-alloyed high-strength low-alloy (HSLA) steel plate was studied by performing compression tests at elevated temperatures. The hot compression tests were carried out at temperatures from 923 K to 1,223 K with strain rates of 0.002 s−1 and 1.0 s−1. A long plateau region appeared for the 0.002 s−1 strain rate, and this was found to be an effect of the balancing between softening and hardening during deformation. For the 1.0 s−1 strain rate, the flow stress gradually increased after the yield point. The temperature and the strain rate-dependent parameters, such as the strain hardening coefficient (n), strength constant (K), and activation energy (Q), obtained from the flow stress curves were applied to the power law of plastic deformation. The constitutive model for flow stress can be expressed as σ = (39.8 ln (Z) – 716.6) · ε(−0.00955ln(Z) + 0.4930) for the 1.0 s−1 strain rate and σ = (19.9ln (Z) – 592.3) · ε(−0.00212ln(Z) + 0.1540) for the 0.002 s−1 strain rate.
Influence of Substituted Elements on Reflection Loss of Ba-Ferrite Nanoparticle
Authors: Yang S. , Jeong K.-Pil. , Park S.-Y. , Kim J.-Gon.
Published: July 2017

Due to the rapid development of the information communication industries, it is expected that next-generation mobile communication devices in the data communication environment will be used at the same time in the L~X band (1–12 GHz). To mutual electric wave interference prevention, research on wave absorbers in L~X band is needed. In this paper, barium ferrite was researched as L~X band wave absorber. The Barium ferrite (BaM, Ba ferrite) substituted by divalent ions (Co2+, Cu2+, Ni2+, Zn2+) and tetravalent ion (Ti4+). The substituted Ba ferrite nanoparticles were fabricated by sol-gel process. Lattice parameter, particle size, magnetic properties, and reflection loss were analyzed by X-ray diffraction (X-RD), a Vibrating Sample Magnetometer (VSM), and a Network Analyzer. Lattice parameter of Ba ferrite was changed 0.0005 to 0.0078 Å in a-b direction, and 0.0187 to 0.0445 Å in c-direction by substituted elements, and it influenced on magnetic anisotropy. In addition, Co-Ti substitution elements influenced that coercive force decrease 5,739 to 2,240 Oe. Moreover, reflection loss frequencies were shifted from 16.3 GHz to 14.4 and 17.4 GHz by substituted elements Co-Ti and Zn-Ti.
Sintering and Microstructures of SUS 316L Powder Produced by 3D Printing Process
Authors: Kim W.J. , Nguyen H.-H. , Kim H.Y. , Nguyen M.-T. , Park H.S. , Kim J.-C.
Published: July 2017

Selective laser sintering (SLS) is a type of laminating sintering technique, using CO2laser with (metal, polymer, and ceramic) powders. In this result, the flake SUS 316L was used to achieve a high porous product, and compare to spherical type. After SLS, the porosity of flake-type sample with 34% was quite higher than that of the spherical-type one that had only 11%. The surface roughness of the flake SLS sample were also investigated in both inner and surface parts. The results show that the deviation of the roughness of the surface part is about 64.40μm, while that of the internal one was about 117.65μm, which presents the containing of high porosity in the uneven surfaces. With the process using spherical powder, the sample was quite dense, however, some initial particles still remained as a result of less energy received at the beneath of the processing layer.
Synthesis and Characterization of Black CoFe2O4 Pigments Using MOOH (M = Fe and Co) Nanorod
Authors: Yu R. , Yun J. , Kim Y.
Published: July 2017

We studied the coloration and phase transformation of various iron based pigment with cobalt substitution method and heat treatment. First, we synthesized well defined one dimensionβ-Fe/CoOOH nanorods using the solid solution method. Yellowishβ-Fe/CoOOH nanorods were transformed into reddish intermediate states and, finally, black CoFe2O4pigments was obtained. Divalent cobalt ions easily occupied tetrahedral sites. The prepared pigments were well characterized in terms of physical properties by using UV-vis, CIELabcolor parameter measurements, SEM (scanning electron microscopy) and XRD (powder X-ray diffraction). In addition, the magnetization property of the prepared CoFe2O4pigment was confirmed by VSM (vibrating sample magnetometer).
Thermal Diffusion of 57Co into Rh Foil for Preparing Mössbauer Source
Authors: Uhm Y.R. , Kim J.J. , Choi S.M. , Son K.J.
Published: July 2017

To establish the coating conditions for57Co, non-radioactive Co ions are dissolved in an acid solution and electroplated on to a rhodium plate. The thermal diffusion of electroplated Co into a rhodium matrix was studied to apply a57Co Mössbauer source. The procedure to form a Co deposited onto Rh foil was established using two different electroplating baths: the acid-based buffer (pH 3) containing boric acid, sodium chloride, and saccharin, and the alkaline-based buffer (pH 10) containing hydrazine hydrate and ammonium citrate. The influence of different annealing conditions was investigated. From the results, the best diffusion degree of electrodeposited Co onto the rhodium matrix was obtained in an annealing process performed at 1100°C for 3 h in vacuum over 10−5hPa.
Study on Effects of Mold Temperature on the Injection Molded Article
Authors: Han J.-H. , Kim Y.-C.
Published: July 2017

This is a study of the effects of temperature of injection mold on the injection molded article. By supplying water of the proper temperature in the cooling line of mold in the cooling process, the mold was the appropriate temperature, and the deformation of the injection molded article was examined according to the mold temperature. In this study, we conducted simulation analysis and experiments, and the results were analyzed. The minimum deformation of the injection molded article model obtained by supplying 50°C water in the cooling line is 0.003 mm, and the maximum deformation was 0.813 mm. Injection molded article models obtained by supplying 20°C water were found to be a minimum of 0.002 mm, with deformation of up to 0.761 mm. When comparing both conditions, the error rate of injection molded article obtained by supplying 20°C water in the mold cooling line was lower by about 0.18%.
Improved Long-Term Stability of Transparent Conducting Electrodes Based on Double-Laminated Electrosprayed Antimony Tin Oxides and Ag Nanowires
Authors: Koo B.-R. , Bae J.-W. , Ahn H.-J.
Published: July 2017

We fabricated double-laminated antimony tin oxide/Ag nanowire electrodes by spin-coating and electrospraying. Compared to pure Ag nanowire electrodes and single-laminated antimony tin oxide/Ag nanowire electrodes, the double-laminated antimony tin oxide/Ag nanowire electrodes had superior transparent conducting electrode performances with sheet resistance ~19.8 Ω/□ and optical transmittance ~81.9%; this was due to uniform distribution of the connected Ag nanowires because of double lamination of the metallic Ag nanowires without Ag aggregation despite subsequent microwave heating at 250°C. They also exhibited excellent and superior long-term chemical and thermal stabilities and adhesion to substrate because double-laminated antimony tin oxide thin films act as the protective layers between Ag nanowires, blocking Ag atoms penetration.
Spontaneous Formation of Titanium Nitride on the Surface of a Ti Rod Induced by Electro-Discharge-Heat-Treatment in an N2 Atmosphere
Authors: Lee W.H. , Yoon Y.H. , Kim Y.H. , Lee Y.K. , Kim J.Y. , Chang S.Y.
Published: July 2017

A single pulse of 2.0 to 3.5 kJ of input energy from a 450 mF capacitor was applied to a commercially pure Ti rod in a N2atmosphere. The surface of the Ti rod transformed from TiO2into titanium nitride in times as short as 159 msec, providing a bimodal morphology of the cross-section. A much higher value of hardness that was observed at the edge of the cross-section was attributed to nitrogen-induced solid-solution hardening that occurred during the electrical discharge process. The activation energy (Ea) for the diffusion process was estimated to be approximately 86.9 kJ/mol. Results show that the electrical discharge process is a possible potential method for the nitriding of Ti; advantages include a short processing time and control of the nitrided layer without dimensional changes.
Influence of Material Coating on the Heat Transfer in a Layered Cu-SiC-Cu Systems
Authors: Strojny-Nędza A. , Pietrzak K. , Teodorczyk M. , Basista M. , Węglewski W. , Chmielewski M.
Published: July 2017

This paper describes the process of obtaining Cu-SiC-Cu systems by way of spark plasma sintering. A monocrystalline form of silicon carbide (6H-SiC type) was applied in the experiment. Additionally, silicon carbide samples were covered with a layer of tungsten and molybdenum using chemical vapour deposition (CVD) technique. Microstructural examinations and thermal properties measurements were performed. A special attention was put to the metal-ceramic interface. During annealing at a high temperature, copper reacts with silicon carbide. To prevent the decomposition of silicon carbide two types of coating (tungsten and molybdenum) were applied. The effect of covering SiC with the aforementioned elements on the composite’s thermal conductivity was analyzed. Results were compared with the numerical modelling of heat transfer in Cu-SiC-Cu systems. Certain possible reasons behind differences in measurements and modelling results were discussed.
Effect of Heat Treatment on Microstructure and Impact Toughness of Ti-6Al-4V Manufactured by Selective Laser Melting Process
Authors: Lee K.-A. , Kim Y.-K. , Yu J.-H. , Park S.-H. , Kim M.-C.
Published: July 2017

This study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-βgrain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment,αandβphase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.
A Fatigue Fracture Study on TDCB Aluminum Foam Specimen of Type Mode III Bonded with Adhesive
Authors: Lee J.H. , Cho J.U.
Published: July 2017

This paper studies the characteristics of junction structure of closed-cell type aluminum foam, which is generally used as a shock absorber. TDCB specimens were designed for mode III type with thickness as a variable and performed a fatigue experiment on them by thickness. As the result, the load value of all specimens peaks under 0 to 25 cycles and decreases as the cycles increase. As the specimen thickens by 10 mm, the maximum load value is 1.2 times. When the thickness increases by 20 mm, the maximum value increases by 1.5 times. This study result can be utilized by investigating the mechanical characteristics of TDCB specimens for mode III type under fatigue loading conditions systematically and efficiently.
A Study on Propagation Property of Fatigue Crack at Composite with Another Material
Authors: Choi K.K. , Cho J.U.
Published: July 2017

In this study, the fatigue crack propagation in composite material is investigated by experimental result. When another material exists at fatigue crack propagation in case of composite, the durability against fatigue crack is smaller or greater than in case of matrix without another material. As another material is composite material, it refers to steel or material. Another material influences the crack propagation. As the experimental results can be agreed with simulation data, all experimental data in this study are verified. These experimental and analysis results can be applied into real field effectively. The estimation of safety design and life will be of great value industrially.
The genetic approach for assessing sea trout stock enhancement efficiency – An example from the Vistula River
Authors: Wąs-Barcz Anna , Bernaś Rafał , Wenne Roman
Published: July 2017

Many countries in the Baltic Sea basin have initiated enhancement programs for Baltic migratory sea trout, Salmo trutta L., to compensate for losses stemming from anthropogenic pressure that has resulted in the declining population abundance of this species. Regular stock enhancement has been conducted in Poland since the 1960s. Currently, over one million sea trout smolts are released into Polish rivers annually. In most Baltic countries, including Poland, stock enhancement depends on hatcheries producing material using spawners caught in native rivers. However, increasing difficulty obtaining spawners in recent years in Poland has meant that stock enhancement performed in the Vistula has been done largely with material obtained from broodstocks. Simultaneously, there is a lack of information regarding the proportion of wild and cultured sea trout in this river basin. This paper is a review of methods applied to identify individuals from natural and artificial sea trout spawning in rivers, and it proposes using genetic techniques as an alternative to traditional marking methods. A set of 13 microsatellite loci are proposed that are characterized by high selectivity. Using negative controls while simulating the assignment of parental pairs revealed that the number of loci in the set was highly significant and should not be reduced. This method could be useful in the proposed assessment of the proportions of wild and cultured fish in Polish rivers.
Terminalia catappa L. extract improves survival, hematological profile and resistance to Aeromonas hydrophila in Betta sp.
Authors: Nugroho Rudy Agung , Manurung Hetty , Nur Firman M. , Prahastika Widha
Published: July 2017

To determine the effects of Terminalia catappa extract (TCE) immersion on the survival and hematological profile of Betta sp, a group of fish was immersed in 500 ppm TCE and compared with the control group. After three days of immersion, survival, leukocyte (WBC), erythrocyte (RBC), hemoglobin (Hb), hematocrit (Hct), platelet (PLT), and differential leukocyte counts were compared between the two groups. Surviving fish from each group were then divided into three subgroups: subgroup without injection; subgroup injected with normal saline; subgroup injected with Aeromonas hydrophila. Survival, WBC, RBC, Hb, Hct, PLT, the percentage and number of lymphocyte, monocyte, and granulocytes post injection were evaluated for 48 h. The results showed that the survival of immersed fish was significantly higher than that in the control. No significant differences in the hematological profile were noted between the control and the immersed fish. The WBC of control subgroup (A. hydrophila injection) was significantly increased after 24 h. The fish immersed and injected with A. hydrophila had the highest PLT. The number of lymphocytes of all subgroups of fish was stable while the percentage of monocytes and granulocytes of the subgroups of immersed fish were increased. This finding suggested that 500 ppm of TCE is beneficial for improving survival, blood profile, and resistance to A. hydrophila.
Seasonal variations in intracellular trace element content and physiological parameters in the lichen Evernia prunastri transplanted to an urban environment
Authors: Vannini Andrea , Paoli Luca , Nicolardi Valentina , Di Lella Luigi Antonello , Loppi Stefano
Published: July 2017

In this study we investigated the seasonal variations in the intracellular content of 14 trace elements (Al, As, Ba, Cd, Ce, Cr, Cu, Fe, Mn, Ni, Pb, Pd, Sb, Zn) and physiological parameters (namely chlorophylla, chlorophyllb, ergosterol, photosynthetic efficiency, cell membrane integrity) in the thalli of the lichenEvernia prunastri(L.) Ach. exposed to an urban environment (Siena, central Italy). Lichen thalli were collected before each exposure period from an unpolluted area and transplanted to 16 sites; every 3 months the thalli were retrieved and replaced with new ones. Exposed-to-control ratios of trace elements revealed a marked intracellular accumulation of Cd in summer and autumn, and of Sb in autumn and spring, possibly as a result of vehicular traffic pollution. However, considering the low absolute concentrations of these elements, the intracellular fraction of depositions may hardly have caused an impairment of physiological parameters. As a matter of fact, indicators of photobiont vitality (content of chlorophyllsaandband photosynthetic efficiency) did not show any fluctuation across seasons, while changes in the indicators of mycobiont vitality (cell membrane damage and ergosterol content) overall did reflect some seasonal changes and/or lichen growth.
Genetic diversity of Potamogeton pectinatus L. in Iran as revealed by ISSR markers
Authors: Abbasi Shabnam , Afsharzadeh Saeed , Saeidi Hojjatollah
Published: July 2017

Potamogeton pectinatusL. is a widespread aquatic species distributed widely in aquatic ecosystems of Iran. In this study, inter simple sequence repeat (ISSR) markers were used to assess the genetic diversity of 35 accessions and 175 individuals ofP. pectinatuscollected from different regions of Iran. In total, 123 polymorphic DNA fragments were amplified from five combinations of ISSR primers. The ISSR based principle coordinate analyses (PCoA) demonstrated four different groups mostly corresponding with their geographic origins (North, Kerman/Fars, Centre and Southwest). The most variable populations were found in the central region of Iran possibly as a consequence of the larger number of samples from that region. The result of molecular variance (AMOVA) attributed 11% of the total genetic variation among and 89% within population variation. The results showed high levels of intra-regional and low inter-regional gene flow between clones, although the Northern accessions were clearly differentiated from the others. There was a low correlation between genetic distance and geographic distance of accessions. The results of STRUCTURE analysis suggested the presence of three genetic groups of this species in Iran, mostly adapted to different ecological conditions. Our results cover one of the gaps of different studies worldwide. In addition, our results confirm high levels of genetic diversity ofP. pectinatusin Iran.
Morphological, anatomical and karyological investigations of the Turkish endemic species Lathyrus woronowii Bornm. (Fabaceae)
Authors: Güneş Fatma , Meriç Çiler
Published: July 2017

Lathyrus woronowiiBornm., an endemic species of Turkey, is threatened with extinction due to dam construction. It exists only in the Çoruh valley, Artvin. This annual species is in the critically endangered (CR) category according to the International Union of Conservation of Nature (IUCN) criteria. Its morphology, anatomy and karyology are studied here for the first time. A detailed description is given and the general appearance of the species has been drawn; cross sections from the stem and leaf have been taken and examined; and the diploid chromosome number (2n = 14) has been reported and illustrated for the first time.