bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multifunctional GdPO4:Pr3+ nanocrystals displaying UV emission, visible emission, and magnetic properties
Authors: Cho Junsang , Kim Chang Hae 
Published: April 2014

ABSTRACTMultifunctional Pr3+-doped GdPO4 nanocrystals possessing UV, visible emissions and magnetic properties were synthesized via co-precipitation and following annealing. It was revealed that as-prepared GdPO4 nanorods were transformed to nanoparticles after heat treatment at 900 °C for 2 hours. Ultimately, GdPO4:Pr3+ nanoparticles have strong UV emission under the excitation of 275 nm and visible emission under the excitation of 445 nm, which offers the optical modalities in both UV and visible range. Moreover, Gd3+-containing nanoparticles are efficient T2-weighted (negative) magnetic resonance (MR) contrast agents due to the presence of Gd3+ ions, which can be potentially applied as multimodal, photoluminescence-magnetic resonance imaging contrast agent.
High-Pressure Annealing of a Prestructured Nanocrystalline Precursor to Obtain Tetragonal and Orthorhombic Polymorphs of Hf3N4
Authors: Salamat Ashkan , Bouvier Pierre , Gray Benjamin M. , Hector Andrew L. , Kimber Simon A. J. , McMillan Paul F. 
Published: April 2014

ABSTRACTTransition metal nitrides containing metal ions in high oxidation states are a significant goal for the discovery of new families of semiconducting materials. Most metal nitride compounds prepared at high temperature and high pressure from the elements have metallic bonding. However amorphous or nanocrystalline compounds can be prepared via metal-organic chemistry routes giving rise to precursors with a high nitrogen:metal ratio. Using X-ray diffraction in parallel with high pressure laser heating in the diamond anvil cell this work highlights the possibility of retaining the composition and structure of a metastable nanocrystalline precursor under high pressure-temperature conditions. Specifically, a nanocrystalline Hf3N4 with a tetragonal defect-fluorite structure can be crystallized under high-P,T conditions. Increasing the pressure and temperature of crystallization leads to the formation of a fully recoverable orthorhombic (defect cottunite-structured) polymorph. This approach identifies a novel class of pathways to the synthesis of new crystalline nitrogen-rich transition metal nitrides.
Price Shocks, News Disclosures, and Asymmetric Drifts
Authors: Lu Hai , Wang Kevin Q. , Wang Xiaolu 
Published: April 2014

ABSTRACT
Motivated by investor disagreement and corporate disclosure literatures, we examine how stock price shocks affect future stock returns. We find that both large short-term price drops and hikes are followed by negative abnormal returns over the subsequent year, consistent with the conjecture that price shocks are useful indicators of intertemporal spikes in investor disagreement and investor opinion converges gradually. The asymmetric drifts involve return continuation for negative price shocks versus return reversal for positive price shocks, and are in sharp contrast to the general findings of symmetric drifts in corporate event studies. Moreover, price shocks associated with public news events are followed by significantly weaker downward drifts, suggesting that news disclosures mitigate disagreement-induced overpricing. Examining the dynamics of a disagreement proxy during and after price shocks, we provide further evidence for the disagreement hypothesis. The economic significance of the price shock effect is illustrated with a revised momentum strategy that generates an annualized abnormal return of 16.92 percent.
Shape Accuracy of Iron Precision Castings in Terms of Ceramic Moulds Physical Properties Anisotropy
Authors: Biernacki R. , Haratym R. , Tomasik J. , Kwapisz J. 
Published: April 2014

Abstract
While analyzing shape accuracy of ferroalloy precision castings in terms of ceramic moulds physical anisotropy, low-alloy steel castings ("cover") and cast iron ("plate") were included. The basic parameters in addition to the product linear shape accuracy are flatness deviations, especially due to the expanded flat surface which is cast plate. For mentioned castings surface micro-geometry analysis was also carried, favoring surface load capacity tp50 for Rmax = 50%. Surface load capacity tp50 obtained for the cast cover was compared with machined product, and casting plate surface was compared with wear part of the conveyor belt. The results were referred to anisotropy of ceramic moulds physical properties, which was evaluated by studying ceramic moulds samples in computer tomography equipment Metrotom 800
Evaluation of Casting Shrinkage and Liquid Metal Fluidity of IN-713C Alloy
Authors: Binczyk F. , Cieśla M. , Gradoń P. , Findziński R. 
Published: April 2014

Abstract
This paper presents the results of measurements of liquid metal fluidity and linear shrinkage of nickel alloy IN-713C in vacuum induction melting furnace Balzers VSG-2. Because of limited volume of the furnace chamber special models for technological trials were designed and constructed to fit in the mould of dimensions 170x95x100mm. Two different designs of test models were proposed: horizontal round rods and modified spiral. Preliminary studies were carried out for alloys Al-Si. Horizontal round rods test was useful for evaluation of fluidity of hypoeutectic silumin, however in case of nickel superalloy the mould cavity was completely filled in each test because of high required pouring temperature. Positive results were obtained from the modified spiral test for all alloys used in the research. Relationship between the linear shrinkage for the test rod and a specific indicator of contraction defined on a spiral was observed.
Some Mechanical Properties of Experimental Mg-Al -RE-Mn Magnesium Alloys
Authors: Braszczyńska-Malik K.N. 
Published: April 2014

Abstract
The results of some mechanical properties of four Mg-5Al-xRE-0.4Mn (x = 1 - 5) alloys are presented. The microstructure of experimental alloys consisted of an α-Mg phase and an α+γ semi-divorced eutectic, Al11RE3 phase and an Al10RE2Mn7 intermetallic compound. For gravity casting in metal mould alloys, Brinell hardness, impact strength, tensile and compression properties at ambient temperature were determined. The performed mechanical tests allowed the author to determine the proportional influence of the mass fraction of rare earth elements in the alloys on their tensile strength, yield strength, compression strength and Brinell hardness. The impact strength of the alloys slightly decreases with a rise in the rare earth elements mass fraction.
The Results of the Brass Refining Process in the Reducer Conditions
Authors: Bydałek A.W. , Bydałek A. 
Published: April 2014

Abstract
This article contains information concerning of the analysis the possibility of defining refinery qualities of the slag based thermo-physical and thermo-dynamical data. It was showed the brass refining with the many-carbide reagents introduced in to the slag. The paper presents the results of the structure analysis of the brass after carbide slag refining in the industrial conditions. The results of the macrostructure analysis have confirmed the argument on high reducing effectiveness of manganese and aluminium carbide used during CuZn39Pb2 alloy melting. The X-Ray microanalysis of the ingot cross-section has shown considerable discrepancies in the disposition of the inclusions. This effects showed on the great influence of reduction melting condition in to the brass melting.
Influence of Binding Rates on Strength Properties of Moulding Sands with the GEOPOL Binder
Authors: Holtzer M. , Drożyński D. , Bobrowski A. , Plaza W. 
Published: April 2014

Abstract
The results of investigations of moulding sands with an inorganic binder called GEOPOL, developed by the SAND TEAM Company are presented in the paper. Hardeners of various hardening rates are used for moulding sands with this binder. The main aim of investigations was determination of the influence of the hardening rate of moulding sands with the GEOPOL binder on technological properties of these sands (bending strength, tensile strength, permeability and grindability). In addition, the final strength of moulding sands of the selected compositions was determined by two methods: by splitting strength and shear strength measurements. No essential influence of the hardening rate on such parameters as: permeability, grindability and final strength was found. However, the sand in which the slowest hardener (SA 72) were used, after 1 hour of holding, had the tensile and bending strength practically zero. Thus, the time needed for taking to pieces the mould made of such moulding sand will be 1.5 - 2 hours.
Characteristics of Non-Ferrous Metal Alloys as Determined by Low-Cycle Fatigue Test under Variable Loads
Authors: Maj M. , Pietrzak K. 
Published: April 2014

Abstract
The paper presents the results of comparative tests of the fatigue properties conducted on two non-ferrous alloys designated as Al 6082 and Al 7075 which, due to the satisfactory functional characteristics, are widely used as engineering materials. The fatigue tests were carried out using a proprietary, modified low cycle test (MLCF). Particular attention was paid to the fatigue strength exponent b and fatigue ductility exponent c. Based on the tests carried out, the results comprised within the range defined by the literature were obtained. These results prove a satisfactory sensitivity of the method applied, its efficiency, the possibility of conducting tests in a fully economical way and above all the reliability of the obtained results of the measurements. Thus, the thesis has been justified that the modified low cycle fatigue test (MLCF) can be recommended as a tool used in the development of alloy characteristics within the range of low-cycle variable loads
The Formation of Gaseous Atmosphere in a Molten Cast Iron/Moulding Sand Contact System
Authors: Mocek J. 
Published: April 2014

Abstract
Drops of molten cast iron were placed on moulding sand substrates. The composition of the forming gaseous atmosphere was examined. It was found that as a result of the cast iron contact with water vapour released from the sand, a significant amount of hydrogen was evolved. In all the examined moulding sands, including sands without carbon, a large amount of CO was formed. The source of carbon monoxide was carbon present in cast iron. In the case of bentonite moulding sand with seacoal and sand bonded with furan resin, in the composition of the gases, the trace amounts of hydrocarbons, i.e. benzene, toluene, styrene and naphthalene (BTX), appeared. As the formed studies indicate much higher content of BTX at lower temperature it was concluded that the hydrocarbons are unstable in contact with molten iron.
Preliminary evaluation of the applicability of F, V and AEsignals in diagnosis of ADI machining process
Authors: Myszka D. , Bombiński S. 
Published: April 2014

Abstract
In this study, a preliminary evaluation was made of the applicability of the signals of the cutting forces, vibration and acoustic emission in diagnosis of the hardness and microstructure of ausferritic ductile iron and tool edge wear rate during its machining. Tests were performed on pearlitic-ferritic ductile iron and on three types of ausferritic ductile iron obtained by austempering at 400, 370 and 320°C for 180 minutes. Signals of the cutting forces (F), vibration (V) and acoustic emission (AE) were registered while milling each type of the cast iron with a milling cutter at different degrees of wear. Based on individual signals from all the sensors, numerous measures were determined such as e.g. the average or maximum signal value. It was found that different measures from all the sensors tested depended on the microstructure and hardness of the examined material, and on the tool condition. Knowing hardness of the material and the cutting tool edge condition, it is possible to determine the structure of the material .Simultaneous diagnosis of microstructure, hardness, and the tool condition is probably feasible, but it would require the application of a diagnostic strategy based on the integration of numerous measures, e.g. using neural networks.
Analysis of the Crystallization of AZ91 Alloy by Thermal and Derivative Analysis Method Intensively Cooled in Ceramic Shell
Authors: Rapiejko C. , Pisarek B. , Czekaj E. , Pacyniak T. 
Published: April 2014

Abstract
The work presents the test result of the influence of cooling rate on the microstructure of AZ91 alloy, Vickers micro-hardness and Brinell hardness. Studies cooling and crystallization of AZ91 alloy was cast into the ceramic shells preheated to 180 ° C and then air-cooled at ambient temperature or intensively super cooled in the liquid coolant. The TDA method was applied to record and characterize the thermal effect resulting from the phase transformations occurring during the crystallization of AZ91 alloy. The kinetics and dynamics of the thermal processes of crystallization of AZ91 alloy in the ceramic shells were determined. Metallographic tests were performed with the use of an optical microscope. A comparison of these test results with the thermal effect recorded by way of the TDA method was made. Influence of cooling rate of AZ91 on HV0, 01 micro-hardness and Brinell hardness alloy was examined
Effect of the Hold Time and Temperatureon Characteristic Quantities of TDACurves
Authors: Szymczak T. , Gumienny G. , Pacyniak T. 
Published: April 2014

Abstract
This paper presents the effect of the temperature and hold time in the holding furnace of 226 silumin on the characteristic quantities of TDA curves. The temperature of phase transformations and the cooling rate were tested.It has been shown that increasing both the hold time and the temperature in the holdingfurnace cause the decreasethe end ofα+Al9Fe3Si2+β and α+Al2Cu+βternary eutectics crystallizationtemperature in the tested silumin. This is due to the fact an increase in amounts of impurities as a result of reacting theliquid alloy with the gases contained in the air.It has been shown, however, that examined technological factors ofthe metal preparation do not cause systematic changes in the cooling rate.
Structural, Dielectric Specroscopy and Internal Friction Correlation in 2NB2O9 Ceramics
Authors: Adamczyk M. , Kozielski L. , Zachariasz R. , Pawełczyk M. , Szymczak L. 
Published: April 2014

Abstract
The research presented in this paper concerns BaBi2Nb2O9 (BBN) which is the member of the Aurivillius family and seems to be interesting from the point of view of its potential applications in storage media. Our investigations focused on temperature dependence crystal structure and mechanical properties of this ceramics as well as on the dielectric properties of samples. Correlation between positions of the maximum of the real part of electric permittivity and the behavior integral width of diffraction lines XRD versus temperature had been discussed based of the presence of polar nano-regions with orthorhombic distortion in macroscopic tetragonal matrix.
Effect of Surface Treatment on Corrosion Resistance of 304 Stainless Steel Implants in Tyrode Solution
Authors: Ahmadian Z. , Danaee I. , Golozar M.A. 
Published: April 2014

Abstract
The effect of different surface preparation methods such as mechanical, chemical and electrochemical surface preparation on the formation, stability and deterioration of surface films formed on austenitic 304 stainless steel was investigated in Tyrode’s physiological solution by cyclic polarization curves, AC impedance measurements surface techniques. A hysteresis loop in a cyclic polarization curve was obtained that indicates a delay in repassivation of an existing pit when the potential is scanned cathodically. Electrolytic polishing and ultrasonic cleaning improves corrosion resistance by increasing the value of the corrosion potential and breakdown potential of the passive layer as well as the pit initiation potential. After mechanical polishing no perfect passivation region was observed. Change in surface fractal is in good agreement with the result obtained from height roughness factor of AFM.
Microstructure and Properties of Cu-Nb Wire Composites
Authors: Głuchowski W.J. , Rdzawski Z.M. , Stobrawa J.P. , Marszowski K.J. 
Published: April 2014

Abstract
Nowadays, there is much activity all over the world in development of Cu-Nb composites for their potential use as conductors in high field magnets. This study was aimed at investigation of microstructure, mechanical and electrical properties of Cu-Nb composite wires. The investigated materials have been processed by vacuum furnace melting and casting, and then hot forging and cold drawing. Initial results of research into Cu-Nb composite material obtained using repeated iterative drawing of niobium wires compacted into copper tube, have been also presented in this article. The ultimate tensile strength versus cold deformation degree has been presented. These changes have been discussed in relation to microstructure evolution. It was assumed that repeated drawing of compacted wires is a promising method for fibrous composite production (more than 823,000 Nb fibres of nanometric diameter) characterized by high mechanical properties and electrical conductivity. Original SPD technique applied for Cu-Nb composite deformation result in initial microstructure refinement and improves effectiveness of wire production process.
Fabrication of Open Cell Fe-10%Al Foam by Space-Holder Technique
Authors: Golabgir M.H. , Ebrahimi-Kahrizsangi R. , Torabi O. , Saatchi A. 
Published: April 2014

Abstract
In this paper, fabrication of open-celled porous Fe-10%A1 foam by space-holder technique in which NaCl powder and polyester resin were utilized as space holder and binder respectively to generate 30-80% porosities was studied. FeAl solid solution was prepared via mechanical alloying method after 25 h high energy milling process. The results indicate that the size and shapes of the pores are determined by the size and shapes of NaCl particles. Also, when compaction pressure was in the range of 70-150 MPa and the sintering process was performed at temperature around 1100°C, the samples had the best quality. Microstructure observations show the pore size was in the range of 200-500 μm.
High-coercivity Nd-Fe-B Powders Obtained by High-Temperature Milling
Authors: Kaszuwara W. , Michalski B. , Orlowski P. 
Published: April 2014

Abstract
The possibility of employing high temperature milling (600°C) for the production of highly coercive Nd-Fe-B powders was examined. The materials were the Nd12Fe82B6, alloy which was subjected to mechanical milling and the powders of the constituent elements of this alloy which were processed by mechanical alloying. The processes were conducted in the two variants: the first variant consisted of mechanical milling performed at a high temperature which was maintained during the entire process, and the other variant included preliminary milling carried out at room temperature and then the milling temperature was increased. All the processes gave nanocrystalline powders with hard magnetic properties. The powders produced by mechanical milling had better properties than those produced by mechanical] alloying as they were more homogeneous and contained smaller amounts of the α-Fe phase.
Fabrication and Characterization of CU/B4C Surface Dispersion Strengthened Composite using Friction Stir Processing
Authors: Sathiskumar R. , Murugan N. , Dinaharan I. , Vijay S.J. 
Published: April 2014

Abstract
Friction stir processing has evolved as a novel method to fabricate surface metal matrix composites. The feasibility to make B4C particulate reinforced copper surface matrix composite is detailed in this paper. The B4C powders were compacted into a groove of width 0.5 mm and depth 5 mm on a 9.5 mm thick copper plate. A tool made of high carbon high chromium steel; oil hardened to 63 HRC, having cylindrical profile was used in this study. A single pass friction stir processing was carried out using a tool rotational speed of 1500 rpm, processing speed of 40 mm/min and axial force of 10 kN. A defect free interface between the matrix and the composite layer was achieved. The optical and scanning electron micrographs revealed a homogeneous distribution of B4C particles which were well bonded with the matrix. The hardness of the friction stir processed zone increased by 26% higher to that of the matrix material.
Synthesis and Characterization of New Refractory Coatings Based on Talc, Cordierite, Zircon and Mullite Fillers for Lost Foam Casting Process
Authors: Prstić A. , Aćimović-Pavlović Z. , Terzić A. , Pavlović L. 
Published: April 2014

Abstract
Refractory coatings based on different refractory fillers (talc, cordierite, zircon and mullite) for application in Lost Foam casting process were investigated. Design and optimization of the coatings composition with controlled, rheological properties included, and consequently synthesis were achieved by application of different coating components, namely different suspension agents and fillers and by alteration of the coating production procedure. Morphologic and microstructural analysis of fillers was carried out by means of scanning electronic microscope. X-ray diffraction analysis by means of X-ray diffractometer was applied in determination and monitoring the phase composition changes of the refractory fillers. An analysis of the particle size and shape was carried out by means of the PC software application package OZARIA 2.5. To assess the effects of application of individual refractory coatings, a detailed investigation of structural and mechanical properties of the moldings obtained was performed. Highlight was placed on revealing and analyzing surface and volume defects present on moldings. Radiographic molding tests were carried out by means of the X-ray device SAIFORT type-S200. Attained results are essential for the synthesis of refractory coatings based on high-temperature fillers and their applications in Lost Foam casting process for manufacturing of moldings with in-advance-set properties.
Fatigue Life Predictions of Metal Matrix Composites Using Artificial Neural Networks
Authors: Uygur I. , Cicek A. , Toklu E. , Kara R. , Saridemir S. 
Published: April 2014

Abstract
In this study, fatigue life predictions for the various metal matrix composites, R ratios, notch geometries, and different temperatures have been performed by using artificial neural networks (ANN) approach. Input parameters of the model comprise various materials (M), such as particle size and volume fraction of reinforcement, stress concentration factor (Kt), R ratio (R), peak stress (S), temperatures (T), whereas, output of the ANN model consist of number of failure cycles. ANN controller was trained with Levenberg-Marquardt (LM) learning algorithm. The tested actual data and predicted data were simulated by a computer program developed on MATLAB platform. It is shown that the model provides intimate fatigue life estimations compared with actual tested data.