bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the Auto-Thermal Performance of a Thermophilic Chalcopyrite Bioleaching Heap Employing Mesophilic and Thermophilic Microbes
Authors: Vilcáez Javier , Suto Koichi , Inoue Chihiro
Published: March 2009

A model was prepared to study the performance of a thermophilic bioleaching heap that
employs mixed mesophilic and thermophilic microbes for copper extraction from CuFeS2.
Mesophiles’ preference for and ease of dissolving additional FeS2 provided to the heap enables the
transition from a mesophilic to a thermophilic bioleaching state without the necessity of additional
energy supply. In this sense, the mathematical description of the bioleaching process is done taking
into consideration the dependency of both microbes’ biological states on physicochemical factors
such as the temperature and O2 availability. With regard to the flow rates of the liquid and air
phases, simulation results have shown that these flow rates govern not just the heat transfer and
variation of cell distribution, but also the leaching rate regardless of the fraction of CuFeS2 per FeS2
leached (FCP) which is the other variable influencing to the heat accumulation in the heap.
Biological Transformation of Kimberlite Ores
Authors: Gericke Mariekie , Benvie Byron , Krüger Leon
Published: March 2009

The weathering of kimberlite ores leads to the weakening of the kimberlite structure,
which allows the use of less intensive comminution procedures during the liberation of diamonds
from the ore, resulting in a decrease in potential damage to the diamonds. The possibility to use
iron- and sulphur-oxidising chemolithotrophic microorganisms as a way to accelerate the
weathering of kimberlite ores was evaluated. It was demonstrated that the presence of sulphuric
acid as well as ferric iron could result in changes in the clay component of these ores. The results
provided promising evidence that weathering can be successfully accelerated, but showed that the
degree of transformation varies between different kimberlite types with different mineralogical
characteristics.
Biooxidation and Cyanidation for Gold and Silver Recovery from Acid Mine Drainage Generating Tailings (Ticapampa, Peru)
Authors: Nagy Adrian A. , Gock Eberhard D. , Melcher Frank , Atmaca Terzan , Hahn Lothar , Schippers Axel
Published: March 2009

The acid mine drainage (AMD) generating sulfidic tailings have a total mass of 1,639,130 t containing 1.65 g/t Au, 34.5 g/t Ag, 7.74 % Fe, 5.91 % S, 3.2 % As, 0.75 % Zn and 0.05 % Cu. The precious metals Au and Ag are enriched in the fine fractions. Approximately 35 % of the material is below 25 /m in size and 53 % below 63 /m. Electron microprobe analysis of a sulfide concentrate of the tailings, produced by gravity separation, proved the occurrence of pyrite and arsenopyrite with appreciable sphalerite and galena. Refractory gold (up to 316 g/t) is hosted in Asrich zones of some arsenopyrites. Approximately 200 g of the sulfide concentrate of the tailings was biooxidized in laboratory shake flasks using an adapted mixed culture of Acidithiobacillus ferrooxidans (Ram 6F), Acidithiobacillus thiooxidans (Ram 8T) and Leptospirillum ferrooxidans (R3). During biooxidation, arsenopyrite was preferentially dissolved and the secondary mineral tooeleite (Fe8(AsO4)6(OH)5·H2O) precipitated. The following cyanidation of the biooxidized sulfide concentrate showed a recovery of 97 % and 50 % for Au and Ag, respectively. The values were 56 % and 18 % for the untreated concentrate. The recovery of Au and Ag from the tailings significantly reduces the costs for the tailings remediation to mitigate AMD release.
A View on the Organic Matter and Metalloporphyrins Biodegradation as Characteristic Components of Black Shale Ores
Authors: Sadowski Zygmunt , Szubert A. , Maliszewska Irena Helena , Jazdzyk Ewa
Published: March 2009

High content of organic compounds is characteristic for black shale-type ores. Metalloporphyrins are known as the most stable and resistant for biodestruction compounds of organic matter. Based on results obtained in previous studies, four metalloporphyrins were synthesised [1]. The experiments of biodestruction of organic matter extracted from polish black shale ore samples and of the synthetic metalloporphyrins were provided using autochthonous, heterotrophic bacteria mixtures isolated form polish black shale samples, and two Streptomyces species. It was found that biodestruction of black shale organic matter and copper- and vanadylporphyrins is possible, but it is a long term process. Porphyrins of Ni and Fe were resistant to biodegradation.
Research for Creation of High-Strength Structures and Joints by Setting up Local Material Properties
Authors: Palkowski Heinz , Rudolph Kai Michael
Published: March 2009

This paper presents the focus of research and the structure of the Collaborative Research
Centre SFB 675 “Creation of High-Strength Structures and Joints by setting up local material
properties” funded in 2006 by the German Research Foundation (DFG).
Design Strategies for the Development of High Strength Coupling Elements from Requirement Optimized Composite Materials
Authors: Lohrengel A. , Schäfer Günter , Wesling Volker
Published: March 2009

New interdisciplinary material and manufacturing technologies make local configuration
of material properties possible. The availability of material property information in the early
construction process and adequate welding technologies are essential needs to realize a maximum
utilization of material. The research objective of two cooperating institutes at the Technical
University of Clausthal is to develop a design strategy with related design rules in order to engineer
high strength coupling elements of requirement optimized composite materials. Special attention is
paid to the usage of future welding technologies and their influence on material properties of locally
altered materials. Further objective is an early survey of the consequences caused by the usage of
locally altered materials in mixed architecture design projects to the whole production process.
Use of Bake Hardening Effects to Change Local Properties of Constructional Elements
Authors: Palkowski Heinz , Brück Anna
Published: March 2009

Within subproject A2 processes leading to local Bake Hardening (BH) effects in
multiphase steels will be investigated. The characteristic values which integrally describe the Bake
Hardening effect depend on the deformation path and the degree of preforming, as well as on
temperature and duration of the subsequent heat treatment. The thermal stability of the induced
strengthening is also determined, in order to specify the boundary conditions for thermal
assembling. Thus, they can be qualified for the assembly of locally strengthened structural
components.
Developments for the Production of Local Foamed Hollow Sections
Authors: Bach Friedrich Wilhelm , Bormann Dirk , Plorin Tillmann
Published: March 2009

The investigation of the basic principles for the production of foamed out sections using
magnesium foam for support structures by including the foaming process into the cold forming of
sections to produce indiviually locally strengthened components is the subject of this research project.
To absorb tensile stress, the metal foam will be strengthened with three-dimensional branched
struts of high-tensile materials. The quantification of the influence of locally introduced foaming
elements on e.g. stiffness alterations and the influence of the resonance frequency of the total structure
will be effected by destructive but particularly also by nondestructive tests.
Selective Strain Hardening of Structure Components by Action Media Based Cold Massive Forming
Authors: Behrens Bernd-Arno , Hagen Thomas , Röhr S. , Sidhu Kanwar Bir
Published: March 2009

High strength aluminium wrought alloys as well as powder metallurgical aluminium
alloys are limited regarding massive formability. The formability at room temperature can be
significantly affected by superimposing hydrostatic pressure. Depending on the process control, cold
forming enables locally induced strain hardening effects, whereby increased hardness or hardness
gradients can be regulated. Simultaneously, the necessity of mechanical post processing is reduced
by a metal forming fabrication of joint and connection elements at room temperature.
By splitting the component in strengthened and not strengthened regions, specially adapted
property profiles can be adjusted to the application. Thus, specially load adapted components with
locally optimised property profiles e.g. ductile or high strength, brittle areas can be manufactured. A
defined buckling or folding of a component in case of a crash can thereby be achieved.
In this project innovative tool principles for superimposed cold solid forming will be developed.
They will be used to manufacture high strength and complex aluminium structure components with
specific adjustment of local strain hardening. A tool technique is to be created in order to generate
locally hardened areas within massive structures by metal forming. Furthermore, the task is to
determine the procedures limits for superimposed cold massive forming with specifically adjusted
strain hardening of aluminium alloys.
For the realisation of these aims fundamental research has to be made, by which the coherences
between specific process parameters and the increased formability are determined. Furthermore, the
cold hardening effects are to be adjusted by cold massive forming with superimposed hydrostatic
pressure and displayed with the help of FEA.
In the long term, the analysis aims at the development of pressure superimposed forming that is
technically utilisable as a near net shape manufacturing process for high complex aluminium
structure components with selective adjustment of local properties.
Effect of Processing Parameters, Particle Characteristics and Metallic Coating on Properties of SiCp Copper Alloy Matrix Composites
Authors: Ivănuş R.
Published: March 2009

The powder metallurgy technique was adopted to prepare SiCp copper alloy matrix
composites. The mechanical properties of the composites were measured to investigate the
influence of processing parameters, SiC particle characteristics and metallic coating (copper) of the
SiC particles. It was found that the mechanical properties of the composites prepared by pressing,
sintering, re-pressing, and resintering are superior to those of composites prepared by the pressing
and sintering route, and that sintering temperature was an important factor in controlling composite
properties. Changes in hardness, theoretical density, ultimate tensile strength, and wear resistance of
composites containing SiC of varying silicon carbide content were observed. In all cases,
composites made from copper coated SiCp exhibited better properties than those from uncoated
particles.
Volume-CAD: An Integrated Environment for Virtual Manufacturing and Structural Analysis
Authors: Ohura K. , Sun Z. , Makinouchi Akitake , Teodosiu Cristian
Published: March 2009

The Volume-CAD System Research Program aims at developing a core technology for
data integration of computerized design, analysis, manufacturing, and testing processes. The
potential applications of the Volume-CAD environment cover a large area of engineering and
biomedical design. In this paper, we shall mainly focus on the VCAD-based software for the
structural analysis and the simulation of casting processes.
Researches on Normalizing Heat Treatment Applied to SAW Joints with TWIN-ARC
Authors: Mitelea Ion , Gavanescu G. , Radu B.
Published: March 2009

In this paper is analyzed the effect of normalizing post-weld heat treatment for SAW
TWIN-ARC on grain size and aging of the Widmannstätten structure. Tests of elongation and
toughness made with welded joints from S355J0 justify heat treatment opportunity and also the
structural modification developed in deposited metal and in heat-affected zone.
Researches Regarding the Structural and Mechanical Characteristics of the C-Mn Steel within the Specific Thermal Circuits
Authors: Pascu Doru Romulus , Bobic A. , Băltean G. , Mateiu Horia
Published: March 2009

The paper presents the experimental results regarding the influence of the multiple
thermal cycles on the structural and mechanical characteristics of the weldable C-Mn steel used in
energetic. Macro- and microscopic examinations, and mechanical testing made on the intersection
welds show that the structural and mechanical characteristics are within the reference range of CMn
(type S355JR) steel. So, the hardness of the pearlitic – ferritic structures in the welded joints
characteristic zones is less than 216 HB; the tensile strength of the welded joints is more than 430
[N /mm2], imposed value for the C-Mn steel. Also, the weld toughness is between 38 [J] and 52 [J]
(at 20 °C), more than 27 [J], value what must be assured for the investigated steel. So, the tendency
to brittle fracture of the welded joints is diminished. The presence of some imperfections within the
intersection welds imposes a carefully monitoring of all these welded joints by adequate nondestructive
examinations.
Hydrides Effect on the SCC Initiation on Zircaloy-4 Claddings
Authors: Dinu Alice , Radulescu M. , Ionescu D. , Florea Silviu
Published: March 2009

The main cause of failure of CANDU-type fuel bundles during their operation is the
Stress Corrosion Cracking (SCC). This mechanism appears in presence of the simultaneous action
of a corrosive agent and of mechanical stress. The presence of precipitated zirconium hydride
platelets can affect the propagation of the SCC cracks. For this reason, we studied the influence of
content of hydrogen on the initiation and the propagation of SCC crack. To do this study, some Crings
samples with different content of hydrogen (100-500ppm) were exposed in a corrosive
environment containing iodine (10-4g/cm2) at 320°C. The stress state, the concentration of the
corrosive environment and the temperature were maintained constant. For comparison, in the same
conditions some as-received samples were exposed. To relieve the morphology of the precipitates
of the zirconium hydride the samples were been investigated using metallographic method, before
and after thermal treatments. While before the experiment a circumferential orientation of the
hydrides precipitates was observed, after the thermal treatments a reorientation of hydrides in a
radial direction was been remarked. Investigation by SEM method revealed the propagation modes
of cracks in the case of the as-received samples and it was put in evidence the existence of the
microcracks on the inner surface of tested samples.
Influence of Magnesium on Structure and Properties of Al-Si Alloy
Authors: Haque Mohammad M. , Khan Ahsan Ali
Published: March 2009

Aluminium-silicon alloys have low density, high electrical and thermal conductivity and
high resistance to corrosion at ambient temperature. However, these alloys usually contain
numerous alloying and impurity elements, which consist essentially of a fairly ductile matrix of
alpha aluminium solid solution with a variety of non-ductile particles of silicon and various
intermetallic compounds. The shape and distribution of these constituents largely control the
deformation behaviour of the alloy. The addition of magnesium makes the alloys lighter and harder,
but its hardening effect is fully responsive only after proper heat treatment. Therefore, in the present
study, microstructures and properties of the alloys have been evaluated on the as-cast and heattreated
conditions. Results show that the addition of magnesium to aluminium-silicon eutectic base
alloy refines microstructure up to certain level and increases the strength and hardness at the
expense of ductility.
Synthesis of Silver Free Eutectic Alloys for Be and Cu99.32Cr0.6Zr0.08 Brazing
Authors: Petrişor Traian , Neamţu Bogdan Viorel , Rufoloni A. , Rauca M. Cristian , Brânduşan Liviu
Published: March 2009

Silver free Ti-43at.%Cu (Ti-Cu) eutectic alloy have been developed for the brazing of Be
and Cu99.32Cr0.6Zr0.08 (CuCrZr). The structural and microstructural properties of the as obtained
alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and
energy dispersive X-ray spectroscopy (EDXS). The analysis have revealed that the Cu-Ti eutectic
alloy have a fine and homogeneous eutectic structure with the phase composition corresponding to
the Ti-Cu phase diagram. These observations are consistent with the thermal properties of the
alloys determined by DTA-TG analysis. The role of Mn on the eutectic structure, as well on the
wetability properties was also studied. The effect of Mn is to produce a less coarse eutectic
structure and to decrease the wetability angle. The mechanical testing of CuCrZr/Ti-Cu/CuCrZr
junctions have demonstrated that these alloys are suitable for the brazing of Be and CuCrZr. The
shear strength of the CuCrZr/TiCuMn/ CuCrZr increases with Mn concentration reaching the value
of about 280 MPa for 2at% Mn.
Tensile Properties of Martensitic Stainless Steel Weldments
Authors: Yilmaz R. , Türkyilmazoglu Ali
Published: March 2009

In this study, AISI 420 martensitic stainless steels were welded by GTAW (gas tungsten
arc welding) using ER 316L consumables. Pure argon, argon + 25% He and argon + 5% N2 were
used as shielding gases. The obtained results indicated that shielding gases have some effect on the
properties of the martensitic stainless steel weldments. The use of argon+5%N2 provides the highest
tensile strength values and higher microhardness profile compared to the other shielding gas
composition used.
Research Concerning the Obtaining From Industrial Wastes of a Cover Powder Used in Steel Continuous Casting
Authors: Ardelean Erika , Hepuţ T. , Ardelean Marius
Published: March 2009

The paper presents research carried out in order to obtain thermo-isolating and covering
powder used in the Tundish of the continuous casting installations. This powder is made by using
different types of waste originating in the iron and steel industry and in the energy industry, such as:
thermal power-station ashes, furnace slag, B.C.A. scraps, limestone, black ash, fluorine, raw
dolomite, graphite powder. The powder thus obtained must have a faster melting speed and a lower
melting temperature; it does not make the steel impure or diminish the heat losses through radiation.
An effect of applying the experimental results in industry, besides financial economies, is to obtain
an accelerated integration of a technological process in companies, according to European Union
requirements regarding the preservation of the environment.
Some Aspects Regarding the Complex Alloying of the Ni3Al Intermetallic Compound with Substitutional and Interstitial Elements
Authors: Lucaci Mariana , Orban Radu L. , Patroi Delia , Hodorogea S. , Bibicu I. , Lungu Magdalena
Published: March 2009

Research results focussed on the combined influence of iron and boron, in proportions of
0.5 and up to 10 wt.% respectively, in complex alloyed Ni3Al synthesised by Self Propagating High
Temperature Synthesis (SHS) in the thermo-explosion mode at two ignition temperatures, 950 and
1150 oC, are presented. By XRD and Mössbauer spectroscopy it was established that for 950 oC
ignition temperature, the evolved heat is not high enough for the added Fe to be fully incorporated
into the synthesised Ni3Al phase, a temperature of 1150 oC being required. For this temperature, the
density of the synthesised alloys, their capacity to be cold deformed by re-pressing, hardness and
bending strength variations as a function of B and Fe contents, proved their cumulative effects of
the ductility and mechanical properties of complex alloyed Ni3Al enhancing.
Devices for Dry Separation of the Spherical Particles from those Having a Non Spherical Shape from a Metallic Powder
Authors: Spârchez Zeno
Published: March 2009

The paper describes the working principles for six types of separation devices mentioned
in the literature, as well as two original types of separation devices devised by the author. In fact the
functionality of each device presented in the paper is based on the difference between the friction
coefficients – sliding friction for non-spherical particles and rolling friction for spherical ones,
respectively. Due to this peculiarity, the two types of particles move along different trajectories,
thus becoming separable. The paper also discusses the limit conditions ensuring the functionality of
each separation device.
On Massive Powder Coating in Ball Milling
Authors: Pop D.A. , Arghir George
Published: March 2009

During ball milling of ductile-brittle systems, often is reported a massive coating of
milling devices (balls and walls of the vials). Therefore, to slow the powder deposit on the milling
devices, it is useful to analyze the causes that initiate and favour the phenomenon. It seems that the
massive powder coating of milling devices is very similar to build-up edging of the materials on the
cutting tools in machining. The aim of the paper is to find what differences appear in the coating
when are used different powder compozitions, or compozitions with fractions of powder previously
milled compared to initialy unmilled compozitions.
Study on the Characteristics of Simply Mixed the Magnetic Abrasives Particles
Authors: Chen Y. , Song Q.H. , Wang X. , Ma Ning
Published: March 2009

Utilize the characteristic that magnetic force line may penetrate the non-magnetic
material, using the magnetic abrasive finishing (MAF) method complete to the non-magnetic small
workpiece surface precise processing. In order to enhance polishing efficiency, usually with the
magnetic particles and abrasive particles mixes together in the sinter method or the cementation
method, the cost is higher; the variety is not also complete. Therefore, use the simply mixed method
mixed the ferromagnetism iron particles, the alumina particles and the lipin, directly participates in
magnetism polishing, already obtained the good processing effect through the experiment. This
paper analysis and explanation the best experimental condition such as the granularity proportion of
the ferromagnetism iron particles and the alumina particles etc.
Experimental Study on Cryogenic Polishing Single Silicon Wafer with Nano-Sized Cerium Dioxide Powders
Authors: Sun Yu Li , Zuo Dun Wen , Zhu Yong Wei , Chen Rong Fa , Li D.S. , Wang M.
Published: March 2009

Cryogenic polishing single silicon wafer with nano-sized CeO2 abrasives can be known as
cryogenic fixed abrasives CMP (CFA-CMP). The abrasive slurry was made of nano-sized CeO2
particles dispersed in de-ionized water with a surfactant and the polishing slurry froze to form
cryogenic polishing pad. Then the polishing tests of the blanket silicon wafers in the presence of the
cryogenic polishing pad containing the nano-particulates were carried out. The morphologies and
surfaces roughness of the polished silicon wafers were observed and examined on an atomic force
microscope (AFM). The results show that a super smooth surface with roughness of 0. 293 nm is
obtained within 5000 nm× 5000 nm and the removal of material is dominated by plastic flowage.
Study on Polishing Rock Minerals of Natural Stone
Authors: Shen Jian Yun , Xu Xi Peng
Published: March 2009

In this study, rock minerals of natural stone were finely polished with loose abrasive and
ELID technology to study the surface behaviours. After these rock specimens were polished to ultra
smooth surfaces, the surface characteristics were observed with microscope and analyzed with
surface texture analyzer. It was found that the calcite and fluorite minerals could be polished to high
surface quality with fine loose aluminum oxide abrasive. But ultra smooth quartz surface must be
finished with superabrasive ELID polishing technology. The weakly acidic coolant might bring
chemical damage to calcite and fluorite minerals under the condition of ELID polishing process.
Study on Removal and Embedding Mechanism of CdZnTe Using Loose Abrasive
Authors: Li Yan , Gao Hang , Kang Ren Ke
Published: March 2009

Cd1−xZnxTe (CZT) is an excellent ternary compound semiconductor. CZT is the most suitable substrate material for Hg1−yCdyTe epitaxial growth and can make the detector itself. The researchers have done a lot of works on the hard and brittle material removal mechanism in lapping process. however, no published articles are available regarding the removal mechanism and the abrasives embedding mechanism of the soft and brittle material in lapping progress .and there is its own characteristic if the hard abrasives machining the soft and brittle material in lapping progress, the objective of this paper is to build the physical model ,and divide the abrasive into four kinds of abrasives , they are two-body abrasive ,three-body abrasive ,embedded abrasive and small abrasive, and the authors analyze the effects on the material surface of the above abrasives. At last, design series of experiments, through analyzing the results and observe the surface morphology, the authors prove that the physical model is correct.
Synthetically Modeling of Thermal Error and Grinding Force Induced Error on a Precision NC Cylindrical Grinding Machine
Authors: Wu Hao , Yang Jian Guo , Wang Xiu Shan
Published: March 2009

Thermal errors and force-induced errors are two most significant sources of the NC
grinding machine inaccuracy. And error compensation technique is an effective way to improve the
manufacturing accuracy of the NC machine tools. Effective compensation relies on an accurate
error model that can predict the errors exactly during machining. In this paper, a PSO–BP neural
network modeling technique has been developed to build the model of the dynamic and highly
nonlinear thermal errors and grinding force induced errors. The PSO–BP neural network modeling
technique not only enhances the prediction accuracy of the model but also reduces the training time
of the neural networks. The radial error of a grinding machine has been reduced from 27 to
8μmafter compensating its thermal error and force-induced error in this paper.
Formation and Simulation of Cutting-Direction Burr in Orthogonal Cutting
Authors: Qu Hai Jun , Wang Gui Cheng , Pei Hong Jie , Li Qin Feng , Zhu Yun Ming
Published: March 2009

The cutting-direction burr is one of the important factors that influence the edge quality and performance of precision parts. The cutting-direction burr formation process is simulated with DeformTH3D. The mechanism of cutting-direction burr formation is analyzed in terms of the results of the simulation. The negative shear zone and initiation negative shear angle are discussed too. Study results show that the deformation of CDE is an important factor affect the cutting direction burrs’ size and shape.
Online Wheel Wear Evaluation in Grinding WC-Co Ceramic Coating
Authors: Zhang Y.H. , Wu Qi , Hu De Jin
Published: March 2009

This paper presented a new technology, which was the online wheel wear evaluation in
grinding WC-Co ceramic coating by using wavelet packet decomposition. On the basis of the
measurement methods, theory of online wear evaluation of wheel was introduced. And the selection
principle of characteristic signals was brought forward, the grinding acceleration signal was the best
choice among many characteristic signals. The time domain signal analysis method of wavelet packet
decomposition was analyzed. Lastly, experiments on the wear of wheel were performed, and the
experimental results showed the validity of the method.
Ultraviolet-Curing Resin: A Novel Bond for Abrasive Tools
Authors: Liu F.Q. , Yao C.Y. , Gao Tao , Peng Wei
Published: March 2009

This paper provides a novel process that can readily make abrasive tools bonded
ultraviolet-curing resin. Excellent characteristics of ultraviolet-curing resin make it possible for
bonding abrasive tools. Moreover, more applications demonstrate that ultraviolet-curing abrasive
tools possess excellent properties without the shortcomings that are encountered in the case of the
conventional resin bonded abrasive tools. Furthermore, various factors influencing the qualities of
ultraviolet-curing abrasive tools are discussed.
Application of ICA Method to Thermal Error Modeling of Gear Hobbing Machine
Authors: Guo Qian Jian , Yang Jian Guo , Wang Xiu Shan
Published: March 2009

Based on the synthetic analysis of thermal error sources, ICA (Independent component
analysis) method is proposed to reduce the number of temperature sensor, and the selected
temperature variables is used for thermal error modeling of gear hobbing machine. Finally, the
hardware system of thermal error compensation is presented based on SCM (Single chip
microcomputer) technique, and which is tested on Y3150K hobbing machine then. The results show
that cumulative pitch error is reduced from 80μmto 20μm, and the machining accuracy is improved
more than 2 grades.
Conditions of Precision Measurement for Error Separation by Multi-Probe Method
Authors: Zhang Lei , Zhang Yu , Ba Lin
Published: March 2009

There are some applications of error separation technique in actual measurement. However there exists a series of theoretical and technical obstacles, and the error separation technique lacks the objective assessment. The further discussion about the character of error separation technique by multi-probe method is made in this paper and six criteria for precision measurement of error separation technique by multi-probe method is also advanced. That is, (1) The criterion for veracity of error separation; (2) The criterion for periodicity of combination signal; (3) The criterion for the remnant first-harmonic in combination signal; (4) The criterion for validity of error separation results; (5) The criterion for validity of probes’ fixing angles ; (6) The criterion for nonzero character of weight function. These criteria are significant for the objective evaluation of the measuring apparatus’ measurement precision, the validity of the sampling data, and the confidence level of error separation results. The validity of the measuring condition was proved by the online measurement experiment.
Prediction of Surface Quality and Parameter in Bearing Convex Raceway Finishing
Authors: Tao Bin , Wang Xu Yue , Zhen H.Z. , Xu Wen Ji
Published: March 2009

Electrochemical abrasive belt grinding (ECABG) technology, which has the advantage over conventional stone super-finishing, has been applied in bearing raceway super-finishing. However, the finishing effect of ECABG is dominated by many factors, which relationship is so complicated that appears non-linear behavior. Therefore, it is difficult to predict the finishing results and select the processing parameters in ECABG. In this paper, Back-Propagation (BP) neural network is proposed to solve this problem. The non-linear relationship of machining parameters was established based on the experimental data by applying one-hidden layer BP neural networks. The comparison between the calculated results of the BP neural network and experimental results under the corresponding conditions was carried out, and the results indicates that it is feasible to apply BP neural network in determining the processing parameters and forecasting the surface quality effects in ECABG.
Study on the Ultrasonic Machining of Hydroxyapatite/SiCw Composite Bioceramics Material
Authors: Niu Zong Wei , Zhao Qing Zhi , Wei Xiu Ting
Published: March 2009

The influence of whisker orientation on machining mechanism, material removal rate
and roughness of finished surface when machining the hydroxyapatite /SiCw composite bioceramics
material using ultrasonic machining technology was studied. The research results show that material
removal rate and roughness of finished surface increase with the increase of the direction angle θ .
Under the same machining condition, the higher is the fracture toughness of the material, the lower
the material removal rate is. This provides basis for the ultrasonic machining of hydroxyapatite
/SiCw composite bioceramics material.
Network Database System for Metal Cutting Burr
Authors: Zhu Yun Ming , Wang Gui Cheng , Wang Zhi , Fan Shu Tian
Published: March 2009

The formation and existence of burrs is one of the common phenomena in machining. It
affects directly machining accuracy and parts quality. Network database system for metal cutting
burr is developed using ASP.NET platform. The management of metal cutting burr data, inquiry
and prediction of cutting burrs types and sizes, optimization of cutting conditions for controlling
burr forming which based on the reasoning method of BP neural networks are realized. The
development and realization of network database of metal cutting burr provide a convenient way for
data transmission between multi-workshop and across regions, promote the development of burr
controlling technology and modern manufacture technology.
Hot Tearing Prediction of Aluminum Alloy in the Casting Process
Authors: Kwak Si Young , Baek Jae Wook , Kim Jeong In , Yoo Seung Mok , Choi Jeong Kil
Published: March 2009

Many engineers want to prevent crack defects because the defect is fatal to casting products
and the desire has induced many studies of the crack generation. However, this study is intricate
because the casting involves a complicated process; Casting products experience large thermal
variations from pouring temperature to room temperature, phase transformation and mechanical
contact with mold during the process. Especially, a crack phenomenon like hot tearing involves an
interaction between stress and metallurgical properties. In this paper, we studied the relationship
between hot tearing and thermal stress considering metallurgical properties. We performed thermal
stress analysis as computational method and proposed a hot tearing predictor including thermal and
mechanical stress phenomena and metallurgical characteristics. The proposed hot tearing predictor is
verified by the results of applying this predictor to different casting conditions.
Real-Time Simulation Measurement System for Transient Temperature of Impacting Droplet Based on the Virtual Instrument
Authors: Yang L. , Fang Jian Cheng , Zhao Zhi Yu , Gao Y.Q.
Published: March 2009

The quality of coatings is directly influenced by the flattening and solidification of many
individual molten droplets in plasma spray forming, so many properties such as thermal, electrical,
mechanical etc are strongly linked to the real contact between the “piled-up” splats. The research on
the transient temperature of impacting droplets and the heat transfer between droplets and substrate
plays an important role in improving the quality of coatings. Because of complexity and high cost of
temperature measurement systems for molten droplet during flattening in plasma spray forming at
present, this paper presents a new kind of simulation measurement system for transient temperature of
spray droplets when impacting on substrate based on LabVIEW, which could display the real-time
changes of the temperature by waveform graph. Finally, the experiments were carried out on Pb-Sn
alloy molten droplets to reveal the close connection between the impacting droplets temperature
changes and the coatings quality, and the heat transfer between droplets and substrate was discussed.
Effects of Heat Treatments on Microstructure of AM50 Magnesium Alloy
Authors: Ma Yan Long , Pan Fu Sheng , Yang Ming Bo
Published: March 2009

The effects of different solid solution and aging technologies on the microstructure of
AM50 were studied. The results indicated that heat-resistant Al-Mn phases were the major second
phases in AM50 alloy under all testing conditions. Highest microhardnesses were obtained not only in
as-aged sample but in as-solution treated sample, which indicated that the strengthening mechanism
for AM50 alloy was not limited to precipitation reinforcement.
Application of Numerical Simulation Technology on the Design of Camera Shell during Die Casting Process
Authors: Yan Hong , Hu Zhi , Suan Ti Shuan
Published: March 2009

The technology of computer numerical simulation on casting process is an important
frontal field of material science and technology. The numerical simulations of camera shell in the
pressure die casting process were carried out. The distributions of temperature and solidification time
in the filling process were obtained. Based on the simulated results and the Niyama criterion G/ R ,
the positions of slack were predicted, which were agreement with the practical result. Consequently,
an improved scheme was presented, in which the workpiece defects were obviously reduced. So it’s
significant for the application of numerical simulation on improving the quality of the casting,
shortening the period of producing, reducing the cost and guiding the engineer for taking reasonable
method to optimize the technological design.
On the Microstructure and Properties of Tungsten Heavy Alloys
Authors: Akhtar Farid
Published: March 2009

In this research, the effect of microstructure on the mechanical properties of tungsten
heavy alloys is discussed. The tensile properties of tungsten heavy alloys are found to be dependent
on volume fraction of W, contiguity and grain size of W particle. The ductility is found to be
influenced by contiguity and connectivity. The volume fraction of matrix increases sharply with the
increase in rare metal oxide impurity, which adversely affects the mechanical properties of tungsten
heavy alloys.
Physical Property Evaluation for High Purity Niobium and Tantalum Rare Metals
Authors: Kim Il Ho , Lee Jung Il , Choi G.S. , Kim J.S.
Published: March 2009

Thermal, electrical and mechanical properties of high purity niobium and tantalum
refractory rare metals were investigated to evaluate the physical purity. Higher purity niobium and
tantalum metals showed lower hardness due to smaller solution hardening effect. Temperature
dependence of electrical resistivity showed a typical metallic behavior. Remarkable decrease in
electrical resistivity was observed for a high purity specimen at low temperature. However, thermal
conductivity increased for a high purity specimen, and abrupt increase in thermal conductivity was
observed at very low temperature, indicating typical temperature dependence of thermal
conductivity for high purity metals. It can be known that reduction of electron-phonon scattering
leads to increase in thermal conductivity of high purity niobium and tantalum metals at low
temperature.
Pb(Zr0.95Ti0.05)O3 Powders Synthesized by PEG Modified Pechini Method: Characterization and Sintering Behavior
Authors: Qiu Shao Jun , Fan Hui Qing , Zheng Xiao Dong , Chen Jin , Yang Chen , Fang Pin Yang
Published: March 2009

To adjust the morphology and crystallinity of the chemically prepared Zr-riched` lead
zirconate titanate (Pb(Zr0.95Ti0.05)O3) powders, polyethylene glycol (PEG 20000) was used in
aqueous solution (modified Pechini method). Thermal analysis of the as-synthesized gel showed two
distinct stages, which indicates the volatilization of water and the decomposition of polymers,
respectively. When the gel were calcined at 400 oC, the powders consisted mainly of perovskite PZT
accompanied with small amounts of secondary phases. The higher the calcination temperature
applied, the stronger the intensity of XRD, which means the crystallinity were improved. Scanning
electron microscopy of as-prepared powders suggested that the powders were soft agglomerate
particles when calcined at 600 to 800 oC. Compared with the normal Pechini method, PEG could help
the formation of crystalline phase and soft agglomerate. When the powders compacts were sintered at
975 to 1125 oC, high pure (>99.5%) of tetragonal phase ceramics were got having relative density of
85% to 94%.
Effect of Cyclic Strain Rate on Environmental Fatigue Behaviors of SA508 Gr.1a Low Alloy Steel in 310°C Deoxygenated Water
Authors: Cho Hyun Chul , Jang Hun , Kim Byoung Koo , Kim In Sup , Jang Chang Heui
Published: March 2009

The low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310oC deoxygenated water
were conducted to investigate the effect of cyclic strain rate on the environmentally assisted cracking
(EAC) mechanisms. The flattened striations and the blunt crack tip, which indicate the occurrence of
the slip dissolution/oxidation, were mainly observed for the specimen tested at 0.008 %/s. On the
other hand, the brittle cracks and the blunt main crack with microcracks, which are the evidences of
the hydrogen-induced cracking (HIC), were observed for the specimens tested at 0.04 and 0.4 %/s.
Through this study, it is thought that the slip dissolution/oxidation dominantly contributes to the
reduction in the fatigue life at a strain rate of 0.008 %/s and the HIC is mainly responsible for the
reduction in the fatigue life at strain rates of 0.04 and 0.4 %/s.
Fatigue Crack Growth Behaviors of AISI Type 347 Nuclear Piping Material
Authors: Yoon Ji Hyun , Lee Jong Man , Kim Maan Won , Lee Bong Sang
Published: March 2009

The effect of the temperature and microstructure on the fatigue crack growth behaviors of
two microstucturally different AISI type 347 stainless steel(SS)s are studied at reactor operating
temperature conditions. From the results, it was observed that the fatigue crack growth rate(FCGR) of
type 347 SS increased as the test temperature was increased. However, its temperature sensitivity was
reduced when the ΔK was large. The measured FCGRs for both TP347-LP and TP347-HP at 25oC
and 345oC were lower than those presented in the ASME code. Especially near the threshold region,
the trend curve in ASME code overestimated the FCGR of type 347 SS when compared with the
obtained data. Even though the effect of the microstructure on the macro-crack growth rate was not
significant during stage 2, the differences between threshold values for the specimen with a high
precipitate density and the one with a low precipitate density were observed. It is assumed that these
differences in the precipitate density, which resulted in a difference in mean free path length of
dislocation movement, are the source of the difference in ΔKth of type 347 steels.
Nanoindentation Characterization of Mechanical Properties of Ferrite and Austenite in Duplex Stainless Steel
Authors: Wang Xiu Fang , Yang Xiao Ping , Guo Zhen Dan , Zhou Yin Chang , Song Hong Wei
Published: March 2009

The mechanical properties of as-cast and hot-forging duplex stainless steel samples with
the same compositions were characterized by nanoindentation. The effect of surface treating method
and working state of the sample on the nanoindentation results of ferrite and austenite were discussed.
The results show that the Young’s modulus and hardness of ferrite and austenite may be affected by
the treating method of sample surface. The difference of Young’s modulus average of ferrite or
austenite between as-cast and hot-forging duplex stainless steel samples is not great, but the hardness
average of ferrite or austenite in hot-forging sample is obviously higher than those of as-cast sample.
The difference of hardness between ferrite and austenite in the same sample is not great, but the
young’s modulus of ferrite is higher than that of austenite.
Characteristics of Residual Stress in P92 Steel Welds
Authors: Yoo Keun Bong , Choi Hyun Sun , Kim Eui Hyun , Kim Jae Hoon
Published: March 2009

Welding residual stress has important influence on the performance of engineering
components. In this paper, the residual stress and FWHM were measured by X-ray diffraction
method to investigate characteristics for P92 steel welds. The aim of the study is to estimate the
residual stress and FWHM distribution characteristics. A compressive residual stress distributed as
a function of depth has a different pattern in welds and base metal. A large tensile residual stress
occurs welds and near the HAZ, but approaches gradually zero as away from the welding center.
Residual stress and FWHM undergo rapid relaxation after PWHT. Also, FWHM is a scalar quantity
without any directional difference and is proportional to hardness on the whole.
Microstructures and Growth Characteristics of Self-Assembled InAs/GaAs Quantum Dots Investigated by Transmission Electron Microscopy
Authors: Kim Hyung Seok , Suh Ju Hyung , Park Chan Gyung , Lee Sang Jun , Noh Sam Kyu , Song Jin Dong , Park Yong Ju , Choi Won Jun , Lee Jung Il
Published: March 2009

The microstructure and strain characteristics of self-assembled InAs/GaAs quantum dots
(QDs) were studied by using transmission electron microscopy. Compressive strain was induced to
uncapped QDs from GaAs substrate and the misfit strain largely increased after the deposition of
GaAs cap layer. Tensile strain outside QD was extended along the vertical growth direction; up to 15
nm above the wetting layer. Vertically nonaligned and aligned stacked QDs were grown by adjusting
the thickness of GaAs spacer layers. The QDs with a lens-shaped morphology were formed in the
early stage of growth, and their apex was flattened by the out-diffusion of In atoms upon GaAs
capping. However, aligned QDs maintained their lens-shaped structure with round apex after capping.
It is believed that their apex did not flatten because the chemical potential gradient of In was relatively
low due to the adjacent InAs QD layers.
The Effect of Strain Rate on the Fracture Modes of Mg Alloys
Authors: Quan Gao Feng , Zhu Da Chuan , Yan Feng , Liu Zhao Ming
Published: March 2009

Bending and impact tests were conducted on magnesium alloys AZ31 and AZ80 in
different microstructure conditions. It is found that the strength parameters are increased quite a lot,
and the ductility parameters (bending flection) decreased with increase in strain rate. The damaged
surface analysis in SEM revealed that, the micro crack nucleation modes, micro crack coalescence
and final crack path are varied with the stress state on the specimen, and the crack nucleation modes
are varied with the initial strain rate. The effect of strain rate on fracture modes is discussed.
Relationship between Tensile Deformation and Crystallographic Orientation of Grains in the Balanced Al-Mg2 Si Alloys
Authors: Horiba Katsunari , Tsukiyama Junji , Matsuda Kenji , Uetani Yasuhiro , Ikeno Susumu
Published: March 2009

Heat-treatable 6000-series alloys are currently used by automotive body sheets. It is
general to improve mechanical properties of the Al-Mg-Si alloy by giving addition of the element
and the thermo-mechanical treatment. The electron backscattered pattern (EBSP) technique has
been performed in order to analyse individual crystallographic orientation in these alloys. Hardness
of the 30%-rolled alloy was higher than that of the 0%-rolled alloy. The Schmid factor of individual
crystal grain was calculated by crystallographic orientation. After adding a little deformation, the
crack was observed at the interface between higher SF and lower SF grains. It was thought that this
crack introduced a fracture from the surface.
Fatigue Life Evaluation of Pipe Welds in Power Plant Using Advanced Nondestructive Methods
Authors: Lee Sang Guk , Yoo Keun Bong , Park Sung Keun , Park Duck Gun
Published: March 2009

The objective of this study is to estimate the feasibility of advanced nondestructive method(X-ray
diffraction, AE(acoustic emission) and BN(barkhausen noise)measurement application for fatigue life
evaluation of the high-temperature pipeline steel such as main steam pipe etc. in power plant. In this study,
various nondestructive tests using various types of specimen simulated low cycle fatigue damage were
performed in order to analyze fatigue properties when fatigue damage conditions become various stages such
as 1/4, 1/2 and 3/4 of fatigue life, respectively. As a result of X-ray diffraction tests for specimens simulated
fatigue damages, we conformed that the variation of the full width at half maximum intensity decreased in
proportion to the increase of fatigue life ratio. And also, AE and BN signal due to fatigue damage has linear
relationship with fatigue life ratio algebraically. From this relationship, it was suggested that direct
expectation of the life consumption rate was feasible.