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Sample records for grinding residue cgr

  1. Finite Element Analysis and Experiment Research on Surface Residual Stress of Ceramics Grinding

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The theoretical model of residual stress of ceramics grinding has been established applying thermal elastoplastic mechanics theory. While grinding at the course of grinding wheel moved along workpiece surface the distributing regulation of residual stress can be simplified into thermal elastioplastic mechanical issue, under the action of the both moving centralized force and heat source. Calculating and evaluating of surface residual stress using current procedure of finite element analysis which has been...

  2. CGR3: A Golgi-Localized Protein Influencing Homogalacturonan Methylesterification

    Institute of Scientific and Technical Information of China (English)

    Michael A. Held; Evan Be; Starla Zemelis; Saunia Withers; Curtis Wilkerson; Federica Brandizzi

    2011-01-01

    Plant cell walls are complex structures that offer structural and mechanical support to plant cells and are ultimately responsible for plant architecture and form.Pectins are a large group of complex polysaccharides of the plant cell wall that are made in the Golgi and secreted to the wall.The methylesterification of pectins is believed to be an important factor for the dynamic properties of the cell wall.Here,we report on a protein of unknown function discovered using an extensive proteomics analysis of cotton Golgi.Through bioinformatic analyses,we identified the ortholog of such protein,here named cotton Golgi-related 3 (CGR3) in Arabidopsis and found that it shares conserved residues with Sadenosylmethionine methyltransferases.We established that CGR3 is localized at the Golgi apparatus and that the expression of the CGR3 gene is correlated with that of several cell wall biosynthetic genes,suggesting a possible role of the protein in pectin modifications.Consistent with this hypothesis,immunofluorescence microscopy with antibodies for homogalacturonan pectins (HG) indicated that the cell walls of cgr3 knockout mutants and plants overexpressing CGR3 are decreased and increased in HG methylesterification,respectively.Our results suggest that CGR3 plays a role in the methylesterification of homogalacturonan in Arabidopsis.

  3. Effect of Grinding and Polishing on the Residual Stress and Bending Strength of a Silicon Nitride Ceramic

    Institute of Scientific and Technical Information of China (English)

    GAO Ling; YANG Haitao; DU Daming; ZHAO Shikun; LI Huaping; YUAN Runzhang

    2005-01-01

    The residual stresses on the surface of the differently ground and polished silicon nitride ceramics were measured using X-ray diffraction and identified by SEM.The effect of the residual stress on the bending strength was investigated.The investigations show that the grinding process can introduce subatantial tensile residual stresses up to 290MPa on the surface of silicon nitride ceramics,which has a significant effect on reducing the bending strength of the ceramics after grinding.Thus,in comparison with the ceramics with a rough surface,the ceramics with a mirror image surface may have a lower strength.Polishing can smooth the residual stresses.When we evaluate the quality of the ceramic components after grinding,we must take residual stress into consideration. The grinding methods and grinding conditions must be carefully selected in order to get the favorite residual stress as well as the surface smoothness.

  4. CGR2 and CGR3 have critical overlapping roles in pectin methylesterification and plant growth in Arabidopsis thaliana.

    Science.gov (United States)

    Kim, Sang-Jin; Held, Michael A; Zemelis, Starla; Wilkerson, Curtis; Brandizzi, Federica

    2015-04-01

    Pectins are critical polysaccharides of the cell wall that are involved in key aspects of a plant's life, including cell-wall stiffness, cell-to-cell adhesion, and mechanical strength. Pectins undergo methylesterification, which affects their cellular roles. Pectin methyltransferases are believed to methylesterify pectins in the Golgi, but little is known about their identity. To date, there is only circumstantial evidence to support a role for QUASIMODO2 (QUA2)-like proteins and an unrelated plant-specific protein, cotton Golgi-related 3 (CGR3), in pectin methylesterification. To add to the knowledge of pectin biosynthesis, here we characterized a close homolog of CGR3, named CGR2, and evaluated the effect of loss-of-function mutants and over-expression lines of CGR2 and CGR3 in planta. Our results show that, similar to CGR3, CGR2 is a Golgi protein whose enzyme active site is located in the Golgi lumen where pectin methylesterification occurs. Through phenotypical analyses, we also established that simultaneous loss of CGR2 and CGR3 causes severe defects in plant growth and development, supporting critical but overlapping functional roles of these proteins. Qualitative and quantitative cell-wall analytical assays of the double knockout mutant demonstrated reduced levels of pectin methylesterification, coupled with decreased microsomal pectin methyltransferase activity. Conversely, CGR2 and CGR3 over-expression lines have markedly opposite phenotypes to the double knockout mutant, with increased cell-wall methylesterification levels and microsomal pectin methyltransferase activity. Based on these findings, we propose that CGR2 and CGR3 are critical proteins in plant growth and development that act redundantly in pectin methylesterification in the Golgi apparatus.

  5. 磨球残余应力的数值模拟及分析%Simulation and Analysis of Residual Stress of Grinding Balls

    Institute of Scientific and Technical Information of China (English)

    袁允社; 张小博

    2009-01-01

    The distribution of residual stress of grinding balls in casting condition was simulated based on the software ProCAST. The stress distribution after heat treating was determined by X-ray diffraction instrument. The results indicate that grinding balls in the metal mould solidify first and then in the sand mould, and the interior structures of grinding balls are compact; there is mass of residual stress in the grinding ball in cast condition,although a definite residual stress can be eliminated after heat treating, an amount of stress still exists.%通过铸造数值模拟软件ProCAST模拟了磨球铸态下的残余应力分布情况,同时通过X射线衍射仪,测定了热处理后磨球试样上应力分布状态.结果表明,磨球金属型部位先凝固,砂型部位后凝固,磨球内部组织致密、无缺陷;铸态下在磨球内有大量的残余应力,热处理后可以消除一定的铸造残余应力,但仍有大量残余应力存在.

  6. Chaos game representation (CGR)-walk model for DNA sequences

    Institute of Scientific and Technical Information of China (English)

    Gao Jie; Xu Zhen-Yuan

    2009-01-01

    Chaos game representation (CGR) is an iterative mapping technique that processes sequences of units, such as nucleotides in a DNA sequence or amino acids in a protein, in order to determine the coordinates of their positions in a continuous space. This distribution of positions has two features: one is unique, and the other is source sequence that can be recovered from the coordinates so that the distance between positions may serve as a measure of similarity between the corresponding sequences. A CGR-walk model is proposed based on CGR coordinates for the DNA sequences. The CGR coordinates are converted into a time series, and a long-memory ARFIMA (p, d, q) model, where ARFIMA stands for autoregressive fractionally integrated moving average, is introduced into the DNA sequence analysis. This model is applied to simulating real CGR-walk sequence data of ten genomic sequences. Remarkably long-range correlations are uncovered in the data, and the results from these models are reasonably fitted with those from the ARFIMA (p, d, q) model.

  7. 纳米结构陶瓷涂层磨削表面残余应力的实验设计%The Experiment Designing of the Surface Residual Stresses after Grinding for Nanostructured Ceramic Coatings

    Institute of Scientific and Technical Information of China (English)

    刘伟香; 王瑶

    2014-01-01

    The nanostructured tungsten carbide / cobalt ( n-WC/12Co ) ceramic coating materials are taken as grinding object , grinding machine and three kinds of grinding wheel are cleverly chosen , by using X ray diffraction instrument and the design of grinding parameters , the paper provided basis for nanostructured ceramic coatings grinding experiments and surface residual stress measurement and follow-up study "grinding parameters on the grinding surface residual stress influence rule".%以近年来新出现的纳米结构碳化钨/钴( n- WC/12Co )陶瓷涂层材料为磨削对象,巧妙选择磨削实验用磨床和三种砂轮,利用X射线衍射仪等设备,通过设计磨削参数,为纳米结构陶瓷涂层的磨削实验和表面残余应力的测量及后续研究“磨削参数对磨削表面残余应力的影响规律”提供依据。

  8. Grind hardening process

    CERN Document Server

    Salonitis, Konstantinos

    2015-01-01

    This book presents the grind-hardening process and the main studies published since it was introduced in 1990s.  The modelling of the various aspects of the process, such as the process forces, temperature profile developed, hardness profiles, residual stresses etc. are described in detail. The book is of interest to the research community working with mathematical modeling and optimization of manufacturing processes.

  9. Grinding Residual Stress Simulation and Experiment Based on Thermal Mechanical Coupling Model%基于热力耦合的磨削残余应力仿真与试验研究

    Institute of Scientific and Technical Information of China (English)

    李厦; 钞俊闯

    2015-01-01

    Based on the grinding experiments of hardened bearing steel GCr15 ,the grinding surface residual stress was measured by X‐ray diffractometry . A finite element model of surface grinding was built according to the thermal elastic‐plastic theory and Johnson‐Cook plastic models .The influences of different moving heat source models on the simulation results of residual stress were studied .The results show that heat source models have no significant effect on the depth of the tensile residual stress ,and the computed residual stress using elliptical heat source model is found to agree best with experimental results .%基于淬硬轴承钢GC r15平面磨削试验,通过X射线衍射法对磨削表面残余应力进行测量。依据热弹塑性理论和Johnson‐Cook塑性模型,建立了平面磨削有限元模型,研究了不同移动热源模型对磨削残余应力仿真结果的影响。结果表明,不同的热源模型对残余拉应力层的深度无显著影响,椭圆热源模型计算的残余应力与实验测量值最为吻合。

  10. The Inlet Engine Valves Grinding Using Different Types of Cutting Fluids and Grinding Wheels

    Directory of Open Access Journals (Sweden)

    Eraldo Jannone da Silva

    2002-06-01

    Full Text Available In this paper an experimental research is presented in which different types of cutting fluids (a cutting oil and three different types of soluble oils and grinding wheels (alumina and vitrified CBN were tested in the inlet engine valves grinding. As evaluation parameters the workpiece residual stress and the grinding wheel wear were analyzed. The cutting fluid and the grinding wheel types adopted resulted in changes in all the parameters, due to the different lubricant abilities among the fluids and due to the differences in the mechanical and thermal properties among the abrasives tested. For grinding this steel, the CBN wheel is the best choice, mainly due to compressive residual stress results obtained for all cutting fluids tested. The cutting oil is the most adequate cutting fluid to be used, due to its higher lubricity and ability in keeping the wheel sharp for longer periods of time, reducing the overall grinding energy and the thermal damage.

  11. GRINDING OF DOUBLE DISC GRINDING MACHINE

    Institute of Scientific and Technical Information of China (English)

    Hu Huiqing

    2005-01-01

    The grinding of two parallel sides of a component is accomplished with the accuracy and higher productivity by passing a blank through the truncated cone shape grinders, which are turned angles. The machine is designated by the name of double disc grinding machine (DDGM). Usually, it is used in the mass production. The relationship between these angles, the accuracy, productivity,allowance and parameters of the machine and technology is explained in detail by math, such as vector analysis, transformation of 3D space coordinates, etc. Therefore, in the aspects of qualitative and quantitative analyses, the grinding potential of DDGM is enormous increased and superior to conventional methods. Furthermore, the theoretical foundation of DDGM grinding design and technology is provided to improve, to expand and to create for future. The established machine design and practical experience of grinding technology will get great benefit by them.

  12. [{sup 11}C]GR103545: novel one-pot radiosynthesis with high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Nabulsi, Nabeel B., E-mail: nabeel.nabulsi@yale.ed [Department of Diagnostic Radiology, PET Center, Yale School of Medicine, PO Box 208048, New Haven, CT 06520-8048 (United States); Zheng Mingqiang; Ropchan, Jim; Labaree, David; Ding Yushin [Department of Diagnostic Radiology, PET Center, Yale School of Medicine, PO Box 208048, New Haven, CT 06520-8048 (United States); Blumberg, Laura [Pfizer Global R and D, Groton, CT 06340 (United States); Huang Yiyun [Department of Diagnostic Radiology, PET Center, Yale School of Medicine, PO Box 208048, New Haven, CT 06520-8048 (United States)

    2011-02-15

    Introduction: GR103545 is a potent and selective kappa-opioid receptor agonist. Previous studies in non-human primates demonstrated favorable properties of [{sup 11}C]GR103545 as a positron emission tomography tracer for in vivo imaging of cerebral kappa-opioid receptor. Nonetheless, advancement of [{sup 11}C]GR103545 to imaging studies in humans was hampered by difficulties of its multiple-step radiosynthesis, which produces a final product with low specific activity (SA), which in turn could induce undesirable physiological side effects resulting from the mass associated with an injected amount of radioactivity. We report herein an alternative radiosynthesis of [{sup 11}C]GR103545 with higher SA and radiochemical yields. Methods: The TRACERLab FXC automated synthesis module was used to carry out the two-step, one-pot procedure. In the first step, the desmethoxycarbonyl precursor was converted to the carbamic acid intermediate desmethyl-GR103545 via transcarboxylation with the zwitterionic carbamic complex, 1,8-diazabicyclo[5.4.0]undec-7-ene-carbon dioxide, in the presence and/or absence of cesium carbonate and tetrabutylammonium triflate. In the second step, the intermediate was radiolabeled at the carboxyl oxygen with [{sup 11}C]methyl trifluoromethanesulfonate to give [{sup 11}C]GR103545. Results: This novel synthesis produced [{sup 11}C]GR103545 with {>=}90% chemical and radiochemical purities and an SA of 290.45{+-}99.9 MBq/nmol at the end of synthesis (n=26). Injectable radioactivity was 1961{+-}814 GBq/{mu}mol with 43 min of average synthesis time from the end of beam. Conclusion: We have developed a practical one-pot method for the routine production of [{sup 11}C]GR103545 with reliably high SA and radiochemical yield, thus allowing the advancement of this radiotracer to imaging applications in humans.

  13. Comparison of Grinding Characteristics of Converter Steel Slag with and without Pretreatment and Grinding Aids

    Directory of Open Access Journals (Sweden)

    Jihui Zhao

    2016-10-01

    Full Text Available The converter steel slag cannot be widely used in building materials for its poor grindability. In this paper, the grinding characteristics of untreated and pretreated (i.e., magnetic separation steel slag were compared. Additionally, the grinding property of pretreated steel slag was also studied after adding grinding aids. The results show that the residues (i.e., oversize substance that passed a 0.9 mm square-hole screen can be considered as the hardly grinding phases (HGP and its proportion is about 1.5%. After the initial 20 min grinding, the RO phase (RO phase is a continuous solid solution which is composed of some divalent metal oxides, such as FeO, MgO, MnO, CaO, etc., calcium ferrite, and metallic iron phase made up most of the proportion of the HGP, while the metallic iron made up the most component after 70 min grinding. The D50 of untreated steel slag could only reach 32.89 μm after 50 min grinding, but that of pretreated steel slag could reach 18.16 μm after the same grinding time. The grinding efficiency of steel slag was obviously increased and the particle characteristics were improved after using grinding aids (GA, especially the particle proportions of 3–32 μm were obviously increased by 7.24%, 7.22%, and 10.63% after 40 min, 50 min, and 60 min grinding, respectively. This is mainly because of the reduction of agglomeration and this effect of GA was evidenced by SEM (scanning electron microscope images.

  14. Analysis on the grinding quality of palm oil fibers by using combined grinding equipment

    Science.gov (United States)

    Gan, H. L.; Gan, L. M.; Law, H. C.

    2015-12-01

    As known, Malaysia is the second largest palm oil producer worldwide after Indonesia, therefore indicating the abundance of its wastes within the country. The plantation would be seen to increase to at least 5.2 million ha by 2020, and the waste generation would be 50-70 times the plantation. However, the efficiency of bulk density is reduced. This is one of the main reasons of the initiation of this size reduction/ grinding research. With appropriate parameters, grinding will be seen to be helping in enhancing the inter-particle bindings, subsequently increasing the quality of final products. This paper focuses on the grinding quality involving palm oil wastes by using the Scanning Electron Microscope (SEM). The samples would first be ground to powder at varying grinding speed and finally got the randomly chosen particles measured to obtain the size range. The grinding speed was manipulated from 15 Hz to 40 Hz. From the data obtained, it was found the particles fineness increased with increasing grinding speed. In general, the size ranged from 45 μm to about 600 μm, where the finest was recorded at the speed of 40 Hz. It was also found that the binding was not so encouraging at very low speeds. Therefore, the optimum grinding speed for oil palm residues lied in the range of 25 Hz to 30 Hz. However, there were still limitations to be overcome if the accuracy of the image clarity is to be enhanced.

  15. Model study of the compact gravity reconstruction; Juryoku inversion `CGR` no model kento

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Y.; Muraoka, A. [Sogo Geophysical Exploration Co. Ltd., Tokyo (Japan)

    1996-05-01

    An examination was made on gravity inversion using a compact gravity reconstruction (CGR) method in gravity tomography analysis. In a model analysis, an analytical region of 100m{times}50m was divided into cells of 10m{times}10m, on the assumption that two density anomalous bodies with a density difference of 1.0g/cm{sup 3} existed with one shallow and the other deep density distribution. The result of the analysis revealed that, in a linear analysis by a general inverse matrix, blurs and blotting were plenty with a tendency of making gravity anomaly attributable to an anomalous distribution of shallow density; that CGR provided a large effect in making a clear contrast of an anomalous part; that, where structures of shallow and deep density anomalies existed, the analysis by CGR was inferior in the restoration of a deep structure with errors enlarged; that, if a gravity traverse was taken long compared with the distribution depth of density anomalies, the analytical precision of a deep part was improved; that an analytical convergence was better with the restriction of density difference given on the large side than on the small side; and so on. 3 refs., 10 figs.

  16. STABLE DIAMOND GRINDING

    Directory of Open Access Journals (Sweden)

    Yury Gutsalenko

    2010-06-01

    Full Text Available The paper generalizes on the one hand theory of kinematic-geometrical simulation of grinding processes by means of tools with working part as binding matrix with abrasive grains located in it in random manner, for example diamond grains, and on the other hand practical performance of combined grinding process, based on introduction of additional energy as electric discharges and called by the organization-developer (Kharkov Polytechnic Institute «diamond-spark grinding» as applied to processing by means of diamond wheel. Implementation of diamond-spark grinding technologies on the basis of developed generalized theoretical approach allows to use the tool with prescribed tool-life, moreover to make the most efficient use of it up to full exhausting of tool-life, determined by diamond-bearing thickness. Development is directed forward computer-aided manufacturing.

  17. Grinding Properties of Abandoned Concrete

    Institute of Scientific and Technical Information of China (English)

    ZHENG Fang-yu; WANG Li-jiu; LI Qiang

    2007-01-01

    The grinding properties of abandoned concrete, which consists primarily of hardened cement, limestone aggregate and river sand, are studied. Theoretical models of grinding are used to explain the experimental observation. The results show that 1) The principle disintegration mechanism of hardened cement and river sand is volumetric grinding, although at later stages grinding of cement becomes difficult because of its flaked structure; 2) The limestone grinding process can be divided into two steps. First, volumetric grinding, with an obvious component of surface grinding, followed by primarily surface grinding as the micro-particle content increases; 3) Initially, the principle mechanism of grinding limestone and river sand is volumetric grinding, albeit less efficient grinding than if these components were ground separately, and; 4) After 10 to 20 min of grinding the grinding bottleneck phenomenon appears and after 20 min of grinding the content of micro-particles is large and surface grinding is the main mechanism while the particle size of the mixture is smaller than that of separately ground river sand and cement but bigger than that of separately ground limestone.

  18. Evaluation of the kappa-opioid receptor-selective tracer [{sup 11}C]GR103545 in awake rhesus macaques

    Energy Technology Data Exchange (ETDEWEB)

    Schoultz, Bent W. [University of Oslo, Department of Chemistry, Oslo (Norway); Hjornevik, Trine; Willoch, Frode [University of Oslo, Centre for Molecular Biology and Neuroscience and Institute of Basic Medical Sciences, Oslo (Norway); Akershus University Hospital, Department of Nuclear Medicine, Loerenskog (Norway); Marton, Janos [ABX Advanced Biochemical Compounds GmbH, Radeberg (Germany); Noda, Akihiro; Murakami, Yoshihiro; Miyoshi, Sosuke; Nishimura, Shintaro [Medical and Pharmacological Research Center Foundation, Basic Research Department, Hakui City, Ishikawa (Japan); Aarstad, Erik [University College of London, Institute of Nuclear Medicine, London (United Kingdom); Drzezga, Alexander [Technische Universitaet Muenchen, Department of Nuclear Medicine, Klinikum rechts der Isar, Munich (Germany); Matsunari, Ichiro [Medical and Pharmacological Research Center Foundation, Clinical Research Department, Hakui City, Ishikawa (Japan); Henriksen, Gjermund [University of Oslo, Department of Chemistry, Oslo (Norway); Technische Universitaet Muenchen, Department of Nuclear Medicine, Klinikum rechts der Isar, Munich (Germany)

    2010-06-15

    The recent development in radiosynthesis of the {sup 11}C-carbamate function increases the potential of [{sup 11}C]GR103545, which for the last decade has been regarded as promising for imaging the kappa-opioid receptor ({kappa}-OR) with PET. In the present study, [{sup 11}C]GR103545 was evaluated in awake rhesus macaques. Separate investigations were performed to clarify the OR subtype selectivity of this compound. Regional brain uptake kinetics of [{sup 11}C]GR103545 was studied 0-120 min after injection. The binding affinity and opioid subtype selectivity of [{sup 11}C]GR103545 was determined in cells transfected with cloned human opioid receptors. In vitro binding assays demonstrated a high affinity of GR103545 for {kappa}-OR (K{sub i} = 0.02 {+-}0.01 nM) with excellent selectivity over {mu}-OR (6 x 10{sup 2}-fold) and {delta}-OR (2 x 10{sup 4}-fold). PET imaging revealed a volume of distribution (V{sub T}) pattern consistent with the known distribution of {kappa}-OR, with striatum = temporal cortex > cingulate cortex > frontal cortex > parietal cortex > thalamus > cerebellum. [{sup 11}C]GR103545 is selective for {kappa}-OR and holds promise for use to selectively depict and quantify this receptor in humans by means of PET. (orig.)

  19. Nitramine Drying & Fine Grinding Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Nitramine Drying and Fine Grinding Facility provides TACOM-ARDEC with a state-of-the-art facility capable of drying and grinding high explosives (e.g., RDX and...

  20. High Performance Grinding and Advanced Cutting Tools

    CERN Document Server

    Jackson, Mark J

    2013-01-01

    High Performance Grinding and Advanced Cutting Tools discusses the fundamentals and advances in high performance grinding processes, and provides a complete overview of newly-developing areas in the field. Topics covered are grinding tool formulation and structure, grinding wheel design and conditioning and applications using high performance grinding wheels. Also included are heat treatment strategies for grinding tools, using grinding tools for high speed applications, laser-based and diamond dressing techniques, high-efficiency deep grinding, VIPER grinding, and new grinding wheels.

  1. Examining of abrasion resistance of hybrid composites reinforced with SiC and Cgr particles

    Directory of Open Access Journals (Sweden)

    M. Łągiewka

    2008-08-01

    Full Text Available The presented work discusses the influence of the type and volume percentage of particulate reinforcement consisting of mixed silicon carbide and graphite on the abrasion wear of hybrid composites with AlMg10 matrix. Also the macro photos of frictional surfaces have been shown and the results of hardness measurements have been presented. The performed examinations have allowed for stating that the mixture of SiC and Cgr particles changes in favour the tribological properties of the matrix alloy. It has been also proved that introducing hard reinforcing particles along with soft lubricating ones allows for achieving the material exhibiting high abrasion resistance, and moreover, the graphite particles protect the abraded surface from the destructive action of silicon carbide particles. Also hardness measurements have been performed and the resulting conclusion is that the composite hardness increases with an increase in volume fraction of the reinforcing particles.

  2. Effect of ultra-fine grinding on functional characteristics of dietary fiber from kiwi residue%超微粉碎对猕猴桃渣膳食纤维功能性质的影响

    Institute of Scientific and Technical Information of China (English)

    杨远通; 钟海雁; 潘曼; 章元日; 李忠海; 李加兴

    2011-01-01

    以猕猴桃渣为原料,通过酶法处理和经过过氧化氢漂白,再经胶体磨超微粉碎得到改性猕猴桃膳食纤维,研究超微粉碎工艺对猕猴桃渣膳食纤维物理性质及功能性质的影响.结果表明:超微粉碎显著提高了膳食纤维的比表面积及持水力,改性后的膳食纤维对NO-2的吸附作用,对葡萄糖的吸附能力,对镉离子和铅离子的吸附能力较对照样品均有明显增强.说明超微粉碎进一步增强了猕猴桃渣膳食纤维保健功能.%The bleached and ultra-fine ground dietary fibers were obtained after enzymatic extraction and H2O2 bleaching by using Kiwi fruit residue as material.The effect of ultra-fine grinding on physical and functional properies of IDF was studied.The results showed that: the water holding capacity and specific surface area of IDF was improved than that of reference substances.The microcrystalline step could increase adsorptive ability of nitrite, absorptive ability for glucose,adsorptive ability for Cd2+ and Pb2+ ions.These factors indicate that the dietary fiber from ultra-fine pulverization should increase health-promoting benefits.

  3. A critical study of high efficiency deep grinding

    CERN Document Server

    Johnstone, I

    2002-01-01

    The recent years, the aerospace industry in particular has embraced and actively pursued the development of stronger high performance materials, namely nickel based superalloys and hardwearing steels. This has resulted in a need for a more efficient method of machining, and this need was answered with the advent of High Efficiency Deep Grinding (HEDG). This relatively new process using Cubic Boron Nitride (CBN) electroplated grinding wheels has been investigated through experimental and theoretical means applied to two widely used materials, M50 bearing steel and IN718 nickel based superalloy. It has been shown that this grinding method using a stiff grinding centre such as the Edgetek 5-axis machine is a viable process. Using a number of experimental designs, produced results which were analysed using a variety of methods including visual assessment, sub-surface microscopy and surface analysis using a Scanning Electron Microscope (SEM), residual stress measurement using X-Ray Diffraction (XRD) techniques, Ba...

  4. Profiling of FSHR negative allosteric modulators on LH/CGR reveals biased antagonism with implications in steroidogenesis.

    Science.gov (United States)

    Ayoub, Mohammed Akli; Yvinec, Romain; Jégot, Gwenhaël; Dias, James A; Poli, Sonia-Maria; Poupon, Anne; Crépieux, Pascale; Reiter, Eric

    2016-11-15

    Biased signaling has recently emerged as an interesting means to modulate the function of many G protein-coupled receptors (GPCRs). Previous studies reported two negative allosteric modulators (NAMs) of follicle-stimulating hormone receptor (FSHR), ADX68692 and ADX68693, with differential effects on FSHR-mediated steroidogenesis and ovulation. In this study, we attempted to pharmacologically profile these NAMs on the closely related luteinizing hormone/chorionic gonadotropin hormone receptor (LH/CGR) with regards to its canonical Gs/cAMP pathway as well as to β-arrestin recruitment in HEK293 cells. The NAMs' effects on cAMP, progesterone and testosterone production were also assessed in murine Leydig tumor cell line (mLTC-1) as well as rat primary Leydig cells. We found that both NAMs strongly antagonized LH/CGR signaling in the different cell models used with ADX68693 being more potent than ADX68692 to inhibit hCG-induced cAMP production in HEK293, mLTC-1 and rat primary Leydig cells as well as β-arrestin 2 recruitment in HEK293 cells. Interestingly, differential antagonism of the two NAMs on hCG-promoted steroidogenesis in mLTC-1 and rat primary Leydig cells was observed. Indeed, a significant inhibition of testosterone production by the two NAMs was observed in both cell types, whereas progesterone production was only inhibited by ADX68693 in rat primary Leydig cells. In addition, while ADX68693 totally abolished testosterone production, ADX68692 had only a partial effect in both mLTC-1 and rat primary Leydig cells. These observations suggest biased effects of the two NAMs on LH/CGR-dependent pathways controlling steroidogenesis. Interestingly, the pharmacological profiles of the two NAMs with respect to steroidogenesis were found to differ from that previously shown on FSHR. This illustrates the complexity of signaling pathways controlling FSHR- and LH/CGR-mediated steroidogenesis, suggesting differential implication of cAMP and β-arrestins mediated by

  5. Unsteady-State Grinding Technology (II) Experimental Studies of Grinding Forces and Force Ratio

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    As is known to all, grinding force is one of the most important parameters to evaluate the whole process of grinding. Generally, the grinding force is resolved to three component forces, namely, normal grinding force F n, tangential grinding force F t and a component force acting along the direction of longitudinal feed which is usually neglected because of insignificance. The normal grinding force F n has influence upon surface deformation and roughness of workpiece, while the tangential grinding force ...

  6. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Chaos game representation (CGR)-walk model for DNA sequences

    Science.gov (United States)

    Gao, Jie; Xu, Zhen-Yuan

    2009-01-01

    Chaos game representation (CGR) is an iterative mapping technique that processes sequences of units, such as nucleotides in a DNA sequence or amino acids in a protein, in order to determine the coordinates of their positions in a continuous space. This distribution of positions has two features: one is unique, and the other is source sequence that can be recovered from the coordinates so that the distance between positions may serve as a measure of similarity between the corresponding sequences. A CGR-walk model is proposed based on CGR coordinates for the DNA sequences. The CGR coordinates are converted into a time series, and a long-memory ARFIMA (p, d, q) model, where ARFIMA stands for autoregressive fractionally integrated moving average, is introduced into the DNA sequence analysis. This model is applied to simulating real CGR-walk sequence data of ten genomic sequences. Remarkably long-range correlations are uncovered in the data, and the results from these models are reasonably fitted with those from the ARFIMA (p, d, q) model.

  7. Bruxism (Teeth Grinding or Clenching) (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Bruxism (Teeth Grinding or Clenching) KidsHealth > For Parents > Bruxism ( ... called bruxism , which is common in kids. About Bruxism Bruxism is the medical term for the grinding ...

  8. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  9. Unsteady-State Grinding Technology (I) Theoretical Generalization and Research on Grinding Mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In conventional grinding theory, it is obvious that there must be a very high hardness difference between grains of the grinding wheel and workpieces. The best grinding wheels are those giving the lowest "natural limiting surface roughness" while cutting at appreciable plunge velocities. With the development of new materials and new machining processes, conventional theories of grinding techniques are no longer suitable to explain many phenomena in the course of grinding procedures. In dealing with precisio...

  10. Ultrasonic precision optical grinding technology

    Science.gov (United States)

    Cahill, Michael J.; Bechtold, Michael J.; Fess, Edward; Wolfs, Frank L.; Bechtold, Rob

    2015-10-01

    As optical geometries become more precise and complex and a wider range of materials are used, the processes used for manufacturing become more critical. As the preparatory stage for polishing, this is especially true for grinding. Slow processing speeds, accelerated tool wear, and poor surface quality are often detriments in manufacturing glass and hard ceramics. The quality of the ground surface greatly influences the polishing process and the resulting finished product. Through extensive research and development, OptiPro Systems has introduced an ultrasonic assisted grinding technology, OptiSonic, which has numerous advantages over traditional grinding processes. OptiSonic utilizes a custom tool holder designed to produce oscillations in line with the rotating spindle. A newly developed software package called IntelliSonic is integral to this platform. IntelliSonic automatically characterizes the tool and continuously optimizes the output frequency for optimal cutting while in contact with the part. This helps maintain a highly consistent process under changing load conditions for a more accurate surface. Utilizing a wide variety of instruments, test have proven to show a reduction in tool wear and increase in surface quality while allowing processing speeds to be increased. OptiSonic has proven to be an enabling technology to overcome the difficulties seen in grinding of glass and hard optical ceramics. OptiSonic has demonstrated numerous advantages over the standard CNC grinding process. Advantages are evident in reduced tool wear, better surface quality, and reduced cycle times due to increased feed rates. These benefits can be seen over numerous applications within the precision optics industry.

  11. THERMAL STUDY ON THE GRINDING OF GRANITE WITH SUPERABRASIVE TOOLS

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In the present paer, a thermal study was conducted for the grinding of granite with diamond tools. Three types of grinding-straight surface grinding, deep grinding(circular sawing), and vertical spindle grinding-were studied. Some surface grinding tests were also conducted using a CBN(cubic boron nitride) wheel. Temperature distributions on the workpiece surface were measured using a foil thermocouple and the energy partition to the workpiece was estimated using a temperature matching method. The temperature for CBN surface grinding was found to be much higher than for diamond grinding. Energy partitions to the granite were 30%~36% for CBN surface grinding, 25%~32% for diamond surface grinding, about 53% for vertical spindle grinding, and 5.5%~9% for diamond deep grinding. The low energy partition value in deep grinding also suggested that more of the heat generated by grinding in this case can be conducted to the grinding tool and promote tool wear.

  12. Surface grinding of intermetallic titanium aluminides

    CERN Document Server

    Gröning, Holger Andreas

    2014-01-01

    A deductive kinematic model of creep-feed and speed-stroke grinding processes is developed to identify possibilities to reduce the energy introduced into the workpiece. By computer tomography analysis and tactile measurements of the grinding wheel the pore volume and the static cutting edge number are determined and included in the model. Based on the kinematic model and the grinding wheel characteristics an analytical evaluation of the specific grinding energy for speed-stroke and creep-feed grinding is carried out. The deducted process design is evaluated in experimental investigations. The

  13. Force Characteristics in Continuous Path Controlled Crankpin Grinding

    Institute of Scientific and Technical Information of China (English)

    ZHANG Manchao; YAO Zhenqiang

    2015-01-01

    Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

  14. Method for grinding precision components

    Science.gov (United States)

    Ramanath, Srinivasan; Kuo, Shih Yee; Williston, William H.; Buljan, Sergej-Tomislav

    2000-01-01

    A method for precision cylindrical grinding of hard brittle materials, such as ceramics or glass and composites comprising ceramics or glass, provides material removal rates as high as 19-380 cm.sup.3 /min/cm. The abrasive tools used in the method comprise a strong, light weight wheel core bonded to a continuous rim of abrasive segments containing superabrasive grain in a dense metal bond matrix.

  15. Analysis of Grinding Force and Elastic Deformation in Thread Grinding Process

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2013-01-01

    Full Text Available Considering the grinding geometry of the thread grinding dynamic contact arc length, a dynamic numerical thread grinding model has been set up on the basis of study of a single grit grinding model. The properties of grinding force and dynamic contact arc-length have been studied by means of the developed numerical model. The results have shown that the angle of helix has little effect on the dynamic contact arc-length than the wheel speed on the dynamic contact arc-length. And the wheel speed also produced a large effect on grinding force.

  16. Study on corrosive grinding of gears

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Careful grinding or honing is usually required in machining of gears in order to improvethe machining quality of gear surface. Thus several grinding additives were used to formulate syn-thetic grinding lubricants similar to superior running-in lubricants. Experimental results show thatthe tooth surface of the produced oblique gear and steel worm becomes extremely smooth aftergrinding at a certain load for about a half to one hour. Especially, the gear surface finished withspecially formulated grinding lubricant reaches mirror-like smoothness. The quality of the geartooth can be improved by corrosive grinding, while the corrosive grinding time can be controlled byadjusting the quantity of the corrosive additives and the speed and load of the gears.

  17. Experimental Setup for Diamond Grinding Using Electrochemical InProcess Controlled Dressing (ECD) of Grinding Wheel

    OpenAIRE

    M. A. Shavva; E. M. Zaharevich

    2014-01-01

    The most effective method for finish machining of hard-metals and alloys is to use the diamond grinding wheels for grinding. An application of diamond wheels significantly increases the employee output, reduces costs, and raises manufacturing efficiency with achieving the high performance properties of treated surfaces.During grinding a working surface of diamond wheel wears out. It adversely affects the cutting capability of the diamond grains, and depending on the grinding conditions can oc...

  18. Specific grinding energy and surface roughness of nanoparticle jet minimum quantity lubrication in grinding

    Directory of Open Access Journals (Sweden)

    Zhang Dongkun

    2015-04-01

    Full Text Available Nanoparticles with the anti-wear and friction reducing features were applied as cooling lubricant in the grinding fluid. Dry grinding, flood grinding, minimal quantity of lubrication (MQL, and nanoparticle jet MQL were used in the grinding experiments. The specific grinding energy of dry grinding, flood grinding and MQL were 84, 29.8, 45.5 J/mm3, respectively. The specific grinding energy significantly decreased to 32.7 J/mm3 in nanoparticle MQL. Compared with dry grinding, the surface roughness values of flood grinding, MQL, and nanoparticle jet MQL were significantly reduced with the surface topography profile values reduced by 11%, 2.5%, and 10%, respectively, and the ten point height of microcosmic unflatness values reduced by 1.5%, 0.5%, and 1.3%, respectively. These results verified the satisfactory lubrication effects of nanoparticle MQL. MoS2, carbon nanotube (CNT, and ZrO2 nanoparticles were also added in the grinding fluid of nanoparticle jet MQL to analyze their grinding surface lubrication effects. The specific grinding energy of MoS2 nanoparticle was only 32.7 J/mm3, which was 8.22% and 10.39% lower than those of the other two nanoparticles. Moreover, the surface roughness of workpiece was also smaller with MoS2 nanoparticle, which indicated its remarkable lubrication effects. Furthermore, the role of MoS2 particles in the grinding surface lubrication at different nanoparticle volume concentrations was analyzed. MoS2 volume concentrations of 1%, 2%, and 3% were used. Experimental results revealed that the specific grinding energy and the workpiece surface roughness initially increased and then decreased as MoS2 nanoparticle volume concentration increased. Satisfactory grinding surface lubrication effects were obtained with 2% MoS2 nanoparticle volume concentration.

  19. Changeing of fly ash leachability after grinding

    Science.gov (United States)

    Lakatos, J.; Szabo, R.; Racz, A.; Banhidi, O.; Mucsi, G.

    2016-04-01

    Effect of grinding on the reactivity of fly ash used for geopolymer production was tested. Extraction technique using different alkaline and acidic solutions were used for detect the change of the solubility of elements due to the physical and mechano-chemical transformation of minerals in function of grinding time. Both the extraction with alkaline and acidic solution have detected improvement in solubility in function of grinding time. The enhancement in alkaline solution was approx. 100% in case of Si and Al. The acidic medium able to dissolve the fly ash higher manner than the alkaline, therefore the effect of grinding was found less pronounced.

  20. Study on the Friction Coefficient in Grinding

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The friction between the abrasive grains and workpi ec e is a crutial factor determining the main grinding output. Few studies have bee n carried out investigating the values of the friction coefficient in grinding, due to the difficulty of direct measurement. In this paper, a mathematical model of the friction coefficient in grinding has been established with the aid of a new grinding parameter C ge, which has close relations to wheel wear rate Z s, metal removal rate Z w, specific energy u and gr...

  1. IMPACT GRINDING OF DAMP MATERIALS

    Directory of Open Access Journals (Sweden)

    Ladaev Nikolay Mikhaylovich

    2012-10-01

    Centrifugal grinders were used to analyze the grinding process. The experimental data have proven that the probability of destruction of damp samples is a lot higher than the one of dry samples, given the same initial dimensions of particles and the loading intensity. The rise in the probability of destruction is stipulated by the fact that that the grinder speed at which crushing is triggered is lower in case of damp samples than in case of dry ones. Expressions for speed that describes destruction initiation and the probability of destruction depending on the type of materials, the moisture content and the loading intensity have been derived.

  2. Manufacturing processes 2 grinding, honing, lapping

    CERN Document Server

    Klocke, Fritz

    2009-01-01

    Presents a view of the most common machining and non-machining manufacturing processes. This volume describes the characteristics of abrasive tools, their design and manufacturing, followed by the fundamentals of grinding fluids. It also discusses grinding of different materials (steel, cast iron, hard and brittle materials, nickel and titanium).

  3. Precision diamond grinding of ceramics and glass

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.; Paul, H.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the effect of machine parameters and material properties on precision diamond grinding of ceramics and glass. The critical grinding depth to initiate the plastic flow-to-brittle fracture regime will be directly measured using plunge-grind tests. This information will be correlated with machine parameters such as wheel bonding and diamond grain size. Multiaxis grinding tests will then be made to provide data more closely coupled with production technology. One important aspect of the material property studies involves measuring fracture toughness at the very short crack sizes commensurate with grinding damage. Short crack toughness value`s can be much less than the long-crack toughness values measured in conventional fracture tests.

  4. Triglyceride-Rich Lipoproteins Modulate the Distribution and Extravasation of Ly6C/Gr1(low) Monocytes.

    Science.gov (United States)

    Saja, Maha F; Baudino, Lucie; Jackson, William D; Cook, H Terence; Malik, Talat H; Fossati-Jimack, Liliane; Ruseva, Marieta; Pickering, Matthew C; Woollard, Kevin J; Botto, Marina

    2015-09-22

    Monocytes are heterogeneous effector cells involved in the maintenance and restoration of tissue integrity. However, their response to hyperlipidemia remains poorly understood. Here, we report that in the presence of elevated levels of triglyceride-rich lipoproteins, induced by administration of poloxamer 407, the blood numbers of non-classical Ly6C/Gr1(low) monocytes drop, while the number of bone marrow progenitors remains similar. We observed an increased crawling and retention of the Gr1(low) monocytes at the endothelial interface and a marked accumulation of CD68(+) macrophages in several organs. Hypertriglyceridemia was accompanied by an increased expression of tissue, and plasma CCL4 and blood Gr1(low) monocyte depletion involved a pertussis-toxin-sensitive receptor axis. Collectively, these findings demonstrate that a triglyceride-rich environment can alter blood monocyte distribution, promoting the extravasation of Gr1(low) cells. The behavior of these cells in response to dyslipidemia highlights the significant impact that high levels of triglyceride-rich lipoproteins may have on innate immune cells.

  5. Triglyceride-Rich Lipoproteins Modulate the Distribution and Extravasation of Ly6C/Gr1low Monocytes

    Directory of Open Access Journals (Sweden)

    Maha F. Saja

    2015-09-01

    Full Text Available Monocytes are heterogeneous effector cells involved in the maintenance and restoration of tissue integrity. However, their response to hyperlipidemia remains poorly understood. Here, we report that in the presence of elevated levels of triglyceride-rich lipoproteins, induced by administration of poloxamer 407, the blood numbers of non-classical Ly6C/Gr1low monocytes drop, while the number of bone marrow progenitors remains similar. We observed an increased crawling and retention of the Gr1low monocytes at the endothelial interface and a marked accumulation of CD68+ macrophages in several organs. Hypertriglyceridemia was accompanied by an increased expression of tissue, and plasma CCL4 and blood Gr1low monocyte depletion involved a pertussis-toxin-sensitive receptor axis. Collectively, these findings demonstrate that a triglyceride-rich environment can alter blood monocyte distribution, promoting the extravasation of Gr1low cells. The behavior of these cells in response to dyslipidemia highlights the significant impact that high levels of triglyceride-rich lipoproteins may have on innate immune cells.

  6. Improved grinding quality inspection of large bearing components using Barkhausen noise analysis

    Science.gov (United States)

    Kolarits, Francis M.

    2014-02-01

    Assuring that the finished surfaces of precision large bearing components are free from grinding injury is important due to the high initial value of these bearings, heavy application loadings and high costs associated with potential reduced service life. Inspecting bearing raceway surfaces for grind burn can be done by nital etching but this method is time consuming, involves using hazardous acids, is non-quantitative and does not provide information about residual stresses. An experimental study was performed to assess scanning Barkhausen Noise Analysis (BNA) to detect various levels of induced grind injury on four steels used in large bearing ring production. Test samples having approximately 0.25 m diameter were fabricated from bearing steels heat treated by case carburizing, induction hardening and through hardening. A series of grinding cycles was designed and subsequently the entire ground surface on each sample was tested by scanning BNA. Selected samples were then evaluated by nital etching or destructive metallurgical tests. BNA results are compared with specific grinding power, nital etch and destructive measurements to show BNA to be an effective technique for identification of grind injury on these steel materials. Similar relative trends in the BNA response are present regardless of alloy or heat treatment.

  7. Crystalline silica dust and respirable particulate matter during indoor concrete grinding - wet grinding and ventilated grinding compared with uncontrolled conventional grinding.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Milz, Sheryl; Ames, April; Susi, Pamela P; Bisesi, Michael; Khuder, Sadik A; Akbar-Khanzadeh, Mahboubeh

    2007-10-01

    The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field.

  8. Progress in abrasive and grinding technology

    CERN Document Server

    Xu, Xipeng

    2009-01-01

    The grinding and abrasive processing of materials are machining techniques which use bonded or loose abrasives to remove material from workpieces. Due to the well-known advantages of grinding and abrasive processes, advances in abrasive and grinding technology are always of great import in enhancing both productivity and component quality. In order to highlight the recent progress made in this field, the editor invited 21 world-wide contributions with the aim of gathering together all of the achievements of leading researchers into a single publication. The authors of the 21 invited papers, of

  9. Stress-induced transformation of retained austenite and residual stress in polishing and grinding of ADI. ADI no kenma kensaku kako ni okeru zanryu austenite no kako yuki hentai to zanryu oryoku

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T.; Tada, S.; Abe, T. (Government Industrial Research Institute, Tohoku, Sendai (Japan)); Kurihana, S. (Fukushima Prefectural Office, Fukushima (Japan))

    1993-06-25

    In the present research, relation between the retained austenite ([gamma]) and residual stress (Sr) on the mechanically worked surface was investigated by an X-ray diffraction to furthermore reform the ADI (Austempered Ductile Iron) which is high toughness automobile part material. As samples, selected were two types of ductile iron which are equivalent to FCD450 and FCD600, respectively. In the main process of thermal treatment, they are austenitized in argon at 1173K in the furnace, held quickly cooled (to between 573 and 648K) a cooled at room temperatures. After the treatment, both of them have no structural differences. As a result of investigating the relation of [gamma]'s stress-induced transformation on the polished and ground surface to both Sr and carbon concentration, the vol% of [gamma] on the worked surface by silicon carbide waterproof abrasive paper and buff is small on the surface where the Sr is high, and both of them are mutually correlative. The [gamma] is so quasi-stable as to be martensitized, if worked, and degraded in mechanical properties. The low carbon ductile iron (less than 1.4% in carbon content) is easy to transform, while the high carbon ductile iron (more than 1.6% in carbon content) is difficult to transform and its [gamma] is stable for the working. 16 refs., 8 figs., 2 tabs.

  10. High Efficiency ELID Grinding of Garnet Ferrite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Hard and brittle materials such as ferrite, optical glass and ceramics have been widely used in many fields because of their good characteristics and still gain more attentions. However, it is difficult to machine and get good surface quality. Some parts made of these materials have large machining allowances and need to be produced with large batch, but the machining efficiency is very low with usual grinding method. So it is of great importance to research the high efficiency grinding technology of hard ...

  11. Multiparameter Optimization and Controlling for Cylindrical Grinding Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper bursts the bondage of conventional no-burn thought, presents an optimum strategy permitting burn appear in grinding roughing stage, but the burning layer can be summed on the following finishing stage. On the base of the basic grinding models, the objective function and constrained functions for the multiparameter optimum grinding models had been built in this paper. By the computer simulation, the nonlinear optimum grinding control parameters had been obtained, and the truth grinding process had...

  12. Mirror Surface Grinding of Steel Bonded Carbides

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The steel bonded carbide, a composite material, is very difficult to be machined to a fine finish mirror surface. In this paper, an electrolytic in-process dressing (ELID) grinding with metallic bond super-hard abrasive wheel was developed for grinding steel bonded carbide GT35. Factors affecting ELID grinding performance were analyzed by an atomic force microscope (AFM). Based on the analysis of AFM topography of the fine ground mirror surface of the steel bonded carbide, a schematic diagram of the mechanism of micro-removal of the ground surface was described. The AFM topography also shows that the hard brittle carbide particles, on the surface of steel bonded carbide, were machined out by ductile cutting. Since the grinding cracks in the ground surface are due to temperature gradient, temperature distribution in the grinding area was analyzed by finite element method (FEM). Experimental results indicate that a good mirror surface with Ra<0.02pm can be obtained by the developed ELID grinding system.

  13. Research on the processing speed of cam grinding

    Science.gov (United States)

    Peng, Baoying; Han, Qiushi

    2011-05-01

    Cam Grinding is a special kind of non-circular machining. The processing speed of cam grinding has a major influence on cam machining precision. In this paper, decomposed the X-axis feed speed and C-axis velocity by the tangential speed and normal speed in accordance with the curvature circle at the point of cam profile grinding. Proposed the cam grinding processing speed model and linear velocity calculation formula, the processing experiment on the CNC camshaft grinding machine results show that the cam grinding speed model is correct. Constant angular speed grinding and constant linear speed grinding are analyzed respectively, which provides a theoretical basis for cam grinding processing speed optimization.

  14. A Review of Literature on analysis of JIG Grinding Process

    DEFF Research Database (Denmark)

    Sudheesh, P. K.; Puthumana, Govindan

    2016-01-01

    in jig grinding, because of their uniformity and purity. In this paper, abrief review of the analysis of jig grinding process considering various research trends is presented. The areas highlighted are: optimization, selection of abrasives, selection of processing conditions and practical considerations......Jig grinding is a process practically used by tool and die makers in the creation of jigs or mating holes and pegs on dies.The abrasives normally used in jig grinding are divided into Natural Abrasives and Artificial Abrasives. Artificial Abrasiveare preferred in manufacturing of grinding wheels....... The optimization of parameters in jig grinding process is important to maximize productivity and to improve quality. The abrasives of hard jig grinding wheels get blunt quickly so these are recommended to grind workpiece of low hardness and soft grinding wheels are recommended for hard material workpieces. The jig...

  15. ONLINE GRINDING WHEEL WEAR COMPENSATION BY IMAGE BASED MEASURING TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    WAN Daping; HU Dejin; WU Qi; ZHANG Yonghong

    2006-01-01

    Automatic compensation of grinding wheel wear in dry grinding is accomplished by an image based online measurement method. A kind of PC-based charge-coupled device image recognition system is schemed out, which detects the topography changes of the grinding wheel surface. Profile data, which corresponds to the wear and the topography, is measured by using a digital image processing method. The grinding wheel wear is evaluated by analyzing the position deviation of the grinding wheel edge. The online wear compensation is achieved according to the measure results. The precise detection and automatic compensation system is integrated into an open structure CNC curve grinding machine. A practical application is carried out to fulfil the precision curve grinding. The experimental results confirm the benefits of the proposed techniques, and the online detection accuracy is less than 5 μm. The grinding machine provides higher precision according to the in-process grinding wheel error compensation.

  16. Properties of Cross-Rolled Low Alloy White Cast Iron Grinding Ball

    Institute of Scientific and Technical Information of China (English)

    CHANG Li-min; LIU Lin; LIU Jian-hua

    2007-01-01

    The low-energy, multi-impact fracture resistance and the abrasiveness of the cross-rolled low alloy white cast iron grinding balls were studied after heat treatments at residual rolling temperature. Moreover, the means by which they are damaged and characters of the wear surface were analyzed. The results show that high resistance to impact fracture and high abrasiveness can be achieved after appropriate heat treatment at residual rolling temperature. This kind of heat treatment technology has several advantages under low impact and hard abrasive. These results are very useful for determining the optimized heat treatment technology at residual rolling temperatures.

  17. Research on Visualization in Scientific Computation of Grinding Temperature Field

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper introduces the concepts, classification and method of visualization in scientific computation. Visual C++ developing tool is used to compute surface grinding forces and grinding temperature field models. The three-dimensional entity model of workpiece is made with OpenGL tool, and the different colors on the workpiece entity show different value of temperature, so the visualization of grinding temperature field is realized. The temperature value of every points in grinding temperature field, the c...

  18. Effection of grinding system rigidity ultra-precision grinding of aspheric mould and error compensation

    Science.gov (United States)

    Yin, S. H.; Gong, S.

    2016-10-01

    In ultra-precision oblique axis grinding process for machining micro aspherical mould, form error of aspherical surface is caused by the inconsistence elastic deformation of grinding system, which derived from differences velocity from inside to out. In this case, whole PV value can meet requirements, however, pits are produced in central after error compensation, which is unworkable. In this paper, mechanism of machining error caused by grinding system rigidity is analyzed, and experiments are carried out. Form error compensation grinding are carried out in the central local area, based on traditional error compensation method, which can effectively eliminate the pits of surface center. In this method, cemented carbide YG8 which diameter is about 6mm is ground. The results showed that the form accuracy under PV 200 nm and under PV 50 nm within the scope of 1 mm, and the surface roughness under Ra2nm.

  19. Grinding of WC–Co hardmetals

    NARCIS (Netherlands)

    Hegeman, J.B.J.W.; Hosson, J.Th.M. De; With, G. de

    2001-01-01

    This paper concentrates on the morphology of the ground surface of cobalt tungsten carbide (WC) composite materials that belong to the category of so-called hardmetals. A deformed and detached surface layer was found on top of the specimens after surface grinding with a diamond wheel. In order to

  20. Method of accurate grinding for single enveloping TI worm

    Institute of Scientific and Technical Information of China (English)

    SUN; Yuehai; ZHENG; Huijiang; BI; Qingzhen; WANG; Shuren

    2005-01-01

    TI worm drive consists of involute helical gear and its enveloping Hourglass worm. Accurate grinding for TI worm is the key manufacture technology for TI worm gearing being popularized and applied. According to the theory of gear mesh, the equations of tooth surface of worm drive are gained, and the equation of the axial section profile of grinding wheel that can accurately grind TI worm is extracted. Simultaneously,the relation of position and motion between TI worm and grinding wheel are expounded.The method for precisely grinding single enveloping TI worm is obtained.

  1. [{sup 11}C]-GR89696, a potent kappa opiate receptor radioligand; in vivo binding of the R and S enantiomers

    Energy Technology Data Exchange (ETDEWEB)

    Ravert, Hayden T. E-mail: htr@jhu.edu; Scheffel, Ursula; Mathews, William B.; Musachio, John L.; Dannals, Robert F

    2002-01-01

    The R and S enantiomers of [{sup 11}C]GR89696, [{sup 11}C]-methyl 4-[(3,4-dichlorophenyl)acetyl]-3-[(1-pyrrolidinyl)methyl] -1-piperazinecarboxylate, were synthesized from their appropriate chiral precursors and [{sup 11}C]methyl chloroformate. The [{sup 11}C]-labeled R enantiomer of GR89696, also known as GR103545, demonstrated high affinity in mouse brain with region to cerebellar ratios at 90 minutes of 11.4 and 8.7 for the hypothalamus and olfactory tubercle, respectively. The [{sup 11}C]-labeled S enantiomer showed low affinity and region to cerebellar ratios of 1 for all brain regions. The [{sup 11}C]-labeled GR103545 exhibited a selective and saturable binding for the kappa opioid receptor.

  2. Fatigue Behavior of Friction Stir-Welded Joints Repaired by Grinding

    Science.gov (United States)

    Vidal, C.; Infante, V.

    2014-04-01

    Fatigue is undoubtedly the most important design criterion in aeronautic structures. Although friction stir-welded joints are characterized by a high mechanical performance, they can enclose some defects, especially in their root. These defects along with the relatively low residual stresses of the friction stir-welding thermomechanical cycle can turn into primary sources of crack initiation. In this context, this article deals with the fatigue behavior of friction stir-welded joints subjected to surface smoothing by grinding improvement technique. The 4-mm-thick aluminum alloy 2024-T351 was used in this study. The fatigue strength of the base material, joints in the as-welded condition, and the sound and defective friction stir-welded joints improved by grinding were investigated in detail. The tests were carried out with a constant amplitude loading and with a stress ratio of R = 0. The fatigue results show that an improvement in fatigue behavior was obtained in the joints repaired by superficial grinding technique. The weld grinding technique is better especially for lower loads and increases the high cycle fatigue strength. The fatigue strength of the improved welded joints was higher than that of the base material.

  3. Research on CNC Turning System of Aspheric Machining Grinding Wheel

    Institute of Scientific and Technical Information of China (English)

    ZOU Qin; GUO Yin-biao

    2005-01-01

    The technology of machining aspheric surface with high precision is the premise for the application of aspheric surface. The grinding machining with error compensation is a commonly used method to machine aspheric surface, which will directly influence the quality of aspheric workpiece surface. Multifunctional CNC grinding wheel truing system is a four-axis CNC truing system which can be applied to grinding wheel truing. In this system,DSP-based multi-axes motion control card is adopted as the controller, and visual C++ is used as development tool.When the design of hardware and software is completed, the system can implement truing of various grinding wheel with high precision aspheric machining such as plane grinding wheel, arc grinding one, and sphere grinding one.

  4. STUDY ON A NEW TYPE OF THROWAWAY SOFT GRINDING WHEELS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In accordance with the difficult problems of belt cross vibrations and effects of belt tension on machine spindle precision in abrasive belt grinding, a new soft grinding wheel is put forward, which is provided with the advantages of belt grinding and can be installed directly on the grinding machine spindle substituting for common grinding wheels. The new soft grinding wheel does not need any ancillary facilities and dressing devices in grinding. With analyzing error of wheel and grinding experiment, the highefficiency grinding characteristics grinding hardbrittle materials has been obtained.

  5. Analysis of surface integrity of grinded gears using Barkhausen noise analysis and x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Vrkoslavová, Lucie; Louda, Petr [Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec (Czech Republic); Malec, Jiři [Department of Analytic Services, PCS s.r.o. (Czech Republic)

    2014-02-18

    The contribution is focused to present results of study grinded gears made of 18CrNiMo7-6 steel used in the wind power plant for support (service) purposes. These gears were case-hardened due to standard hard case and soft core formation. This heat treatment increases wear resistance and fatigue strength of machine parts. During serial production some troubles with surface integrity have occurred. When solving complex problems lots of samples were prepared. For grinding of gears were used different parameters of cutting speed, number of material removal and lots from different subsuppliers. Material characterization was carried out using Barkhausen noise analysis (BNA) device; X-ray diffraction (XRD) measurement of surface residual stresses was done as well. Depth profile of measured characteristics, e.g. magnetoelastic parameter and residual stress was obtained by step by step layers' removing using electrolytic etching. BNA software Viewscan was used to measure magnetizing frequency sweep (MFS) and magnetizing voltage sweep (MVS). Scanning of Magnetoelastic parameter (MP) endwise individual teeth were also carried out with Viewscan. These measurements were done to find problematic surface areas after grinding such as thermal damaged locations. Plots of the hardness and thickness of case-hardened layer on cross sections were measurered as well. Evaluation of structure of subsurface case-hardened layer and core was made on etched metallographic patterns. The aim of performed measurements was to find correlation between conditions of grinding, residual stresses and structural and magnetoelastic parameters. Based on correlation of measured values and technological parameters optimizing the production of gears will be done.

  6. Analysis of surface integrity of grinded gears using Barkhausen noise analysis and x-ray diffraction

    Science.gov (United States)

    Vrkoslavová, Lucie; Louda, Petr; Malec, Jiři

    2014-02-01

    The contribution is focused to present results of study grinded gears made of 18CrNiMo7-6 steel used in the wind power plant for support (service) purposes. These gears were case-hardened due to standard hard case and soft core formation. This heat treatment increases wear resistance and fatigue strength of machine parts. During serial production some troubles with surface integrity have occurred. When solving complex problems lots of samples were prepared. For grinding of gears were used different parameters of cutting speed, number of material removal and lots from different subsuppliers. Material characterization was carried out using Barkhausen noise analysis (BNA) device; X-ray diffraction (XRD) measurement of surface residual stresses was done as well. Depth profile of measured characteristics, e.g. magnetoelastic parameter and residual stress was obtained by step by step layers' removing using electrolytic etching. BNA software Viewscan was used to measure magnetizing frequency sweep (MFS) and magnetizing voltage sweep (MVS). Scanning of Magnetoelastic parameter (MP) endwise individual teeth were also carried out with Viewscan. These measurements were done to find problematic surface areas after grinding such as thermal damaged locations. Plots of the hardness and thickness of case-hardened layer on cross sections were measurered as well. Evaluation of structure of subsurface case-hardened layer and core was made on etched metallographic patterns. The aim of performed measurements was to find correlation between conditions of grinding, residual stresses and structural and magnetoelastic parameters. Based on correlation of measured values and technological parameters optimizing the production of gears will be done.

  7. System Analysis of Flat Grinding Process with Wheel Face

    Directory of Open Access Journals (Sweden)

    T. N. Ivanova

    2014-01-01

    Full Text Available The paper presents a conducted system analysis of the flat grinding wheel face, considers the state parameters, input and output variables of subsystems, namely: machine tool, workpiece, grinding wheel, cutting fluids, and the contact area. It reveals the factors influencing the temperature and power conditions for the grinding process.Aim: conducting the system analysis of the flat grinding process with wheel face expects to enable a development of the system of grinding process parameters as a technical system, which will make it possible to evaluate each parameter individually and implement optimization of the entire system.One of the most important criteria in defining the optimal process conditions is the grinding temperature, which, to avoid defects appearance of on the surface of component, should not exceed the critical temperature values to be experimentally determined. The temperature criterion can be useful for choosing the conditions for the maximum defect-free performance of the mechanical face grinding. To define the maximum performance of defect-free grinding can also use other criteria such as a critical power density, indirectly reflecting the allowable thermal stress grinding process; the structure of the ground surface, which reflects the presence or absence of a defect layer, which is determined after the large number of experiments; flow range of the diamond layer.Optimal conditions should not exceed those of defect-free grinding. It is found that a maximum performance depends on the characteristics of circles and grade of processed material, as well as on the contact area and grinding conditions. Optimal performance depends on the diamond value (cost and specific consumption of diamonds in a circle.Above criteria require formalization as a function of the variable parameters of the grinding process. There is an option for the compromise of inter-criteria optimality, thereby providing a set of acceptable solutions, from

  8. Experimental Setup for Diamond Grinding Using Electrochemical InProcess Controlled Dressing (ECD of Grinding Wheel

    Directory of Open Access Journals (Sweden)

    M. A. Shavva

    2014-01-01

    Full Text Available The most effective method for finish machining of hard-metals and alloys is to use the diamond grinding wheels for grinding. An application of diamond wheels significantly increases the employee output, reduces costs, and raises manufacturing efficiency with achieving the high performance properties of treated surfaces.During grinding a working surface of diamond wheel wears out. It adversely affects the cutting capability of the diamond grains, and depending on the grinding conditions can occur through different mechanisms. Wear of diamond wheel causes distortion of its shape and reduces cutting properties. However, dressing of diamond wheels is a complicated and time-consuming operation in terms of manufacturing technique.Methods to make dressing of diamond grinding wheel have different types of classification. Classification of dressing methods by the type of energy used is as follows: mechanical, chemical, electrophysical, electromechanical, and electrochemical. All these methods have their advantages and disadvantages.Electrochemical method of dressing is the most productive and efficient. Electrochemical method comprises anode-mechanical dressing and electrochemical (electrolytic one. The paper presents the electrochemical in-process dressing (ECD and the electrolytic in-process dressing (ELID.The source of energy, grinding a wheel with metal bond, and an electrode are necessary for providing ELID. The ELID consists of several stages. The first stage is preliminary electrolytic dressing of diamond wheel. The electrolyte is placed into the gap between the wheel and electrode. The bond of the wheel is oxidized. An insulating layer is formed. It reduces an electrical conductivity of the wheel and controls consumption of diamond grains, as well as polishes the surface of the work piece. Further, the insulating layer is destroyed. The cycle of dressing begins anew.The ECD proceeds in the same way as ELID. However during the ECD-process there

  9. Bending Distortion Analysis of a Steel Shaft Manufacturing Chain from Cold Drawing to Grinding

    Science.gov (United States)

    Dias, Vinicius Waechter; da Silva Rocha, Alexandre; Zottis, Juliana; Dong, Juan; Epp, Jérémy; Zoch, Hans Werner

    2017-04-01

    Shafts are usually manufactured from bars that are cold drawn, cut machined, induction hardened, straightened, and finally ground. The main distortion is characterized by bending that appears after induction hardening and is corrected by straightening and/or grinding. In this work, the consequence of the variation of manufacturing parameters on the distortion was analyzed for a complete manufacturing route for production of induction hardened shafts made of Grade 1045 steel. A DoE plan was implemented varying the drawing angle, cutting method, induction hardening layer depth, and grinding penetration depth. The distortion was determined by calculating curvature vectors from dimensional analysis by 3D coordinate measurements. Optical microscopy, microhardness testing, residual stress analysis, and FEM process simulation were used to evaluate and understand effects of the main carriers of distortion potential. The drawing process was identified as the most significant influence on the final distortion of the shafts.

  10. Kinetic study of ferronickel slag grinding at variation of ball filling and ratio of feed to grinding balls

    Science.gov (United States)

    Sanwani, Edy; Ikhwanto, Muhammad

    2017-01-01

    The objective of this paper is to investigate the effect of ball filling and ratio of feed to grinding balls on the kinetic of grinding of ferronickel slag in a laboratory scale ball mill. The experiments were started by crushing the ferronickel slag samples using a roll crusher to produce -3 mesh (-6.7 mm) product. This product, after sampling and sample dividing processes, was then used as feed for grinding process. The grinding was performed with variations of ball filling and ratio of feed to grinding balls for 150 minutes. At every certain time interval, particle size analysis was carried out on the grinding product. The results of the experiments were also used to develop linear regression model of the effect of grinding variables on the P80 of the product. Based on this study, it was shown that P80 values of the grinding products declined sharply until 70 minutes of grinding time due to the dominant mechanism of impact breakage and then decreased slowly after 70 minutes until 150 minutes of grinding time due to dominant mechanism of attrition breakage. Kinetics study of the grinding process on variations of grinding ball filling showed that the optimum rate of formation of fine particles for 20%, 30%, 40% and 50% mill volume was achieved at a particle size of 400 µm in which the best initial rate of formation occurred at 50% volume of mill. At the variations of ratio of feed to grinding balls it was shown that the optimum rate of grinding for the ratio of 1:10, 1: 8 and 1: 6 was achieved at a particle size of 400 µm and for the ratio of 1: 4 was at 841 µm in which the best initial rate of formation occurred at a 1:10 ratio. In this study, it was also produced two regression models that can predict the P80 value of the grinding product as a function of the variables of grinding time, ball filling and the ratio of the feed to grinding balls.

  11. Separate critical condition for ultrasonic vibration assisted grinding

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Hong-li; ZHANG; Jian-hua

    2009-01-01

    Separate characteristic of the tangential ultrasonic vibration assisted grinding(TUAG)machining is analyzed based on TUAG process, and a critical speed formula is given to correctly set the machining parameters to insure the separate characteristics of TUAG process. The critical speed is not only related to the ultrasonic vibration amplitude and frequency, but also to the grinding wheel velocity and the cutting point space, and the grinding force can be decreased during the TUAG process with separability. Grinding force experiments are conducted, and the experimental results are in good agreement with the theoretical results.

  12. Study on the New Grinding Fluids of Oils on Water

    Institute of Scientific and Technical Information of China (English)

    魏源迁; 钱怡; 中村隆; 松原十三生

    2003-01-01

    To fulfill a zero-emission in the process of grinding and thoroughly eliminate the influences of the conventional grinding fluids on the eco-environment as well as save up electric energy and reduce in production costs, the new grinding fluids of botanic oils on water were developed, in which a lot of tiny water droplets attached with micro oil films were blown to the machining area by a compressing air-jet so good as to produce lubricating and cooling roles.In this study, grinding performances of the new fluids were investigated by comparison to the conventional ones such as emulsion on the plane NC grinder.

  13. Thermo-mechanical properties of bowl-shaped grinding wheel and machining error compensation for grinding indexable inserts

    Institute of Scientific and Technical Information of China (English)

    张祥雷; 姚斌; 陈彬强; 孙维方; 王萌萌; 罗琪

    2015-01-01

    In order to meet the technical requirements of grinding the circumferential cutting edge of indexable inserts, thermo-mechanical properties of bowl-shaped grinding wheel in high speed grinding process and the influence of dimension variations of the grinding wheel on machining accuracy were investigated. Firstly, the variation trends of the dimension due to centrifugal force generated in different wheel speeds were studied and the effect of stress stiffening and spin softening was presented. Triangular heat flux distribution model was adopted to determine temperature distribution in grinding process. Temperature field cloud pictures were obtained by the finite element software. Then, dimension variation trends of wheel structure were acquired by considering the thermo-mechanical characteristic under combined action of centrifugal force and grinding heat at different speeds. A method of online dynamic monitoring and automatic compensation for dimension error of indexable insert was proposed. By experimental verification, the precision of the inserts satisfies the requirement of processing.

  14. Quenching simulation of steel grinding balls

    Energy Technology Data Exchange (ETDEWEB)

    Zapata-Hernandez, O.; Reyes, L. A.; Camurri, C.; Carrasco, C.; Garza-Monte-de-Oca, F.; Colas, R.

    2015-07-01

    The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses. (Author)

  15. Development of a LPP CGR combustion system with ultra-low emissions for a SOLO 161 Stirling engine based micro-CHP unit

    Energy Technology Data Exchange (ETDEWEB)

    Paalsson, Magnus [Lund Univ. (Sweden). Dept. of Heat and Power Engineering

    2001-07-01

    During the last decade extensive research has been made at Lund University, Sweden, on a lean premix (prevaporize) combustion concept with burnt gas recirculation and a metallic flame holder. From this concept a new lean premixed natural gas combustion chamber with internal combustion gas recirculation (CGR) has been developed for the V160/SOLO 161 Stirling engines. This combustor has ultra-low emission levels, comparable to those of catalytic combustion. At the start of the current project the combustor was ready to be adapted for production, with expected market introduction in 2001. The Lund combustion chamber was modified to investigate the impact of air-fuel ratio and combustion gas recirculation rate on emissions and controllability of the combustion system, and on pressure losses in the combustion chamber. Different start-up strategies as well as different fuel-gas control valves were tried in order to find well-working control routines/parameters. The combustion chamber was redesigned using the gained knowledge, making it easy to manufacture while giving it maximum life expectancy and durability. The SOLO 161 Stirling engine's control system was adapted to the new combustion system. Emissions of the final combustion system were measured and found to be close to the design goal values. Combustor function and reliability has proved to be very good.

  16. Occlusal Grinding Pattern during Sleep Bruxism and Temporomandibular Disorder

    Directory of Open Access Journals (Sweden)

    Yeni Wijaya

    2013-09-01

    Full Text Available Sleep Bruxism is a significant etiology of temporomandibular disorder (TMD and causes many dental or oral problems such as tooth wear or facet. There is no study analyzing the relationship between sleep bruxism and TMD. Objective: To investigate any relationship between occlusal grinding pattern during sleep bruxism and temporomandibular disorder. Methods: A cross-sectional study involving 30 sleep bruxism patients attended the Faculty Dentistry Universitas Indonesia Teaching Hospital (RSGMP FKG UI. Completion of 2 forms of ID-TMD index and questionnaire from American Academy of Sleep Medicine were done. BruxChecker was fabricated and used for two nights to record the occlusal grinding pattern. The occlusal grinding pattern was categorized into laterotrusive grinding (LG and mediotrusive side. Further divisons of LG were: incisor-canine (IC, incisor-caninepremolar (ICP and incisor-canine-premolar-molar (ICPM. Mediotrusive side was classified as mediotrusive contact (MC and mediotrusive grinding (MG. Results: It was found that occlusal grinding pattern in non-TMD subjects were IC+MC, in subjects with mild TMD were ICP+MG and in subjects with moderate TMD were ICP+MG and ICPM+MG. TMJ was more significantly affected by ICP and ICPM grinding pattern than that of IC. Conclusion: There was a significant relationship between occlusal grinding pattern during sleep bruxism and TMD.DOI: 10.14693/jdi.v20i2.149

  17. 7 CFR 58.726 - Cutting and grinding.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cutting and grinding. 58.726 Section 58.726 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections...

  18. Stochastic dynamic programming applied to planning of robot grinding tasks

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M.L. (Digital Equipment Corp., Shrewsbury, MA (United States)); Whitney, D.E. (Massachusetts Inst. of Technology, Cambridge, MA (United States))

    1994-10-01

    This paper proposes an intelligent manufacturing system that can make decisions about the process in light of the uncertain outcome of these decisions and attempts to minimize the expected economic penalty resulting from those decisions. It uses robot weld bead grinding as an example of a process with significant process variations. The need for multiple grinding passes, the poor predictability of those passes, the task requirements, and the process constraints conspire to make planning and controlling weld bead grinding a formidable probe. A three tier hierarchical control system is proposed to plan an optimal sequence of grinding passes, dynamically simulate each pass, execute the planned sequence of controlled grinding passes, and modify the pass sequence as grinding continues. The top tier, described in this paper, plans the grinding sequence for each weld bead, and is implemented using Stochastic Dynamic Programming, selecting the volumetric removal and feedspeed for each pass in order to optimize the satisfaction of the task requirements by the entire grinding sequence within the equipment, task, and process constraints. The resulting optimal policies have quite complex structures, showing foresight, anxiety, indifference, and aggressiveness, depending upon the situation.

  19. Integrated Modeling and Intelligent Control Methods of Grinding Process

    Directory of Open Access Journals (Sweden)

    Jie-sheng Wang

    2013-01-01

    Full Text Available The grinding process is a typical complex nonlinear multivariable process with strongly coupling and large time delays. Based on the data-driven modeling theory, the integrated modeling and intelligent control method of grinding process is carried out in the paper, which includes the soft-sensor model of economic and technique indexes, the optimized set-point model utilizing case-based reasoning, and the self-tuning PID decoupling controller. For forecasting the key technology indicators (grinding granularity and mill discharge rate of grinding process, an adaptive soft-sensor modeling method based on wavelet neural network optimized by the improved shuffled frog leaping algorithm (ISFLA is proposed. Then, a set point optimization control strategy of grinding process based on case-based reasoning (CBR method is adopted to obtain the optimized velocity set-point of ore feed and pump water feed in the grinding process controlled loops. Finally, a self-tuning PID decoupling controller optimized is used to control the grinding process. Simulation results and industrial application experiments clearly show the feasibility and effectiveness of control methods and satisfy the real-time control requirements of the grinding process.

  20. Computer Simulation of Batch Grinding Process Based on Simulink 5.0

    Institute of Scientific and Technical Information of China (English)

    LI Xia; YANG Ying-jie; DENG Hui-yong; HUANG Guang-yao

    2005-01-01

    How to use Simulink software in grinding system was studied. The method of designing batch grinding subsystem and the steps of building batch grinding blockset were introduced. Based on batch grinding population balance model, batch grinding was simulated with Simulink. The results show that the simulation system designed with Simulink explain reasonably the impersonal rule of batch grinding. On the basis of batch grinding simulation, the computer simulation of mineral processing system with Simulink of grinding and classification, comminution, etc, can be properly explored.

  1. Three-dimensional measurement and characterization of grinding tool topography

    Science.gov (United States)

    Cui, Changcai; Blunt, Liam; Jiang, Xiangqian; Xu, Xipeng; Huang, Hui; Ye, Ruifang

    2013-01-01

    A comprehensive 3-dimensional measurement and characterization method for grinding tool topography was developed. A stylus instrument (SOMICRONIC, France) was used to measure the surface of a metal-bonded diamond grinding tool. The sampled data was input the software SurfStand developed by Centre for Precision Technology (CPT) for reconstruction and further characterization of the surface. Roughness parameters pertaining to the general surface and specific feature parameters relating to the grinding grits, such as height and angle peak curvature have been calculated. The methodology of measurement has been compared with that using an optical microscope. The comparison shows that the three-dimensional characterization has distinct advantages for grinding tool topography assessment. It is precise, convenient and comprehensive so it is suitable for precision measurement and analysis where an understanding of the grinding tool and its cutting ability are required.

  2. Monitoring Grinding Wheel Redress-life Using Support Vector Machines

    Institute of Scientific and Technical Information of China (English)

    Xun Chen; Thitikorn Limchimchol

    2006-01-01

    Condition monitoring is a very important aspect in automated manufacturing processes. Any malfunction of a machining process will deteriorate production quality and efficiency. This paper presents an application of support vector machines in grinding process monitoring. The paper starts with an overview of grinding behaviour. Grinding force is analysed through a Short Time Fourier Transform (STFT) to identify features for condition monitoring. The Support Vector Machine (SVM) methodology is introduced as a powerful tool for the classification of different wheel wear situations.After training with available signal data, the SVM is able to identify the state of a grinding process. The requirement and strategy for using SVM for grinding process monitoring is discussed, while the result of the example illustrates how effective SVMs can be in determining wheel redress-life.

  3. Specific Properties of Air Flow Field Within the Grinding Zone

    Institute of Scientific and Technical Information of China (English)

    ZHENG Junyi; JIANG Zhengfeng; ZHAO Liang

    2006-01-01

    Air barrier of grinding means a boundary layer of air existing at the circumference of the rotating wheel, which hinders coolant from entry. This paper makes a research on air flow field of the grinding zone through experiments and numerical simulations, focusing on acquainting with the specific properties of the air flow field. Finite volume method is applied to analyze air flow field within grinding wheel in the course of numerical calculations. The test devices such as Hot-wire anemometer and Betz manometer are used during the experiments of testing the pressure and velocity within grinding zone. Results of experiments agree by and large with numerical results of calculations. The conclusions obtained in this paper, the distribution of wall pressure and the distribution of air flow velocity, are important and useful to navigate the delivery of coolant into the grinding zone. In conclusion, some recommendations are made for further study and practical applications in such field.

  4. Research on product size and grinding dynamics of vibration mills

    Institute of Scientific and Technical Information of China (English)

    YIN Zhong-jun; HAN Tian; CHEN Bing; ZHANG Wen-zhong

    2007-01-01

    In order to improve vibration mills grinding effect and increase productive efficiency, prime factors of vibration mills were gained much attention. The purpose of this study is to reveal product size distribution and grinding dynamics of vibration mills by orthogonal experi-ments. The metallurgical refractory materials were used as research object. In order to explore the relationships between grinding effect and primary factors, lots of milling experiments were carried out. Based on the results, the conclusions can be summarized: as time runs, the size distri-bution shows exponential trend, and range becomes more and more narrow. Also the quantitative analysis result between grinding effect and primary factors was obtained by non-linear regres-sion: high frequency, high amplitude and low fill ratio can increase grinding speed.

  5. Influence of ageing, grinding and preheating on the thermal behaviour of alpha-lactose monohydrate.

    Science.gov (United States)

    Garnier, S; Petit, S; Mallet, F; Petit, M-N; Lemarchand, D; Coste, S; Lefebvre, J; Coquerel, G

    2008-09-01

    It is shown that the onset temperature and the magnitude of thermal events observed during DSC analyses of alpha-lactose monohydrate can be strongly affected by various treatments such as ageing, manual grinding and preheating (cycle of preliminary dehydration and rehydration). In the case of grinding and preheating, the change of dehydration pathways was further investigated by using a suitable combination of characterization techniques, including X-ray powder diffraction (XRPD) performed with a synchrotron source (allowing an accurate Rietveld analysis), scanning electron microscopy (SEM), laser particle size measurements, FTIR spectroscopy and (1)H NMR for the determination of beta-lactose contents in samples. It appeared that the dehydration mechanism is affected not only by a smaller particle size distribution, but also by residual anisotropic lattice distortions and by the formation of surface defects or high energy surfaces. The fusion-recrystallization process occurring between anhydrous forms of alpha-lactose at ca. 170 degrees C is not significantly affected by grinding, whereas a preheating treatment induces an unexpected large increase of the enthalpy associated with this transition. Our observations and interpretations confirm the important role of water molecules in the crystal cohesion of the title compound and illustrate the necessity to consider the history of each sample for a satisfactory understanding of the physical properties and the behaviour of this important pharmaceutical excipient.

  6. Investigations of spherical grinding parameters on circularity error, finished diameter, and grinding forces for porous polyurethane foam

    Directory of Open Access Journals (Sweden)

    Isarawit Chaopanich

    2010-07-01

    Full Text Available The aim of this study was to examine the effect of grinding variables on the circularity error, finished diameter, andgrinding forces of porous polyurethane foam (PPUF. A cube of PPUF having the size of 21 mm was transformed into a roundshape using a vertical wheel grinding with the circular groove pad developed. The grinding speed (Vs of the wheel wasvaried between 1.41 and 5.18 m/s. The cross head speed of the circular groove pad (f was controlled at 1, 3, 5 mm/min. Theabrasive grit size (A of 20 and 53 μm made of silicon carbide were applied. Two replications of experiment were randomlyperformed. Diameter and circularity error of the ground specimen were determined by vision measuring machine. The tangentialand normal forces of grinding were obtained using a dynamometer. The experimental data were statistically analyzed. The study found that (1 the grinding speed could remarkably affect the circularity error, finished diameter, and grinding forces,(2 the grinding speed ranged between 2.83 and 3.77 m/s could contribute to sphere shape specimens, and (3 the grinding speed of 3.30 m/s, cross head speed of 1 mm/min, and abrasive grit size of 20 μm provided the least circularity error.

  7. Numerical Simulation of a Grinding Process for the Spatial Work-pieces: Modeling of Grinding Forces and System Dynamics

    Directory of Open Access Journals (Sweden)

    I. A. Kiselev

    2015-01-01

    Full Text Available The paper describes a computation-experimental technique to determine model coefficients of grinding forces using a Nelder-Mead algorithm. As an error function, the paper offers a deviation measure of calculating and experimental grinding forces averaged for a single-pass of the grinding wheel. As an example of cutting forces model coefficients calculation for linear model, in which the grinding forces depend on uncut chip thickness is analyzed. The coefficients vary on abrasive grain geometric parameters and are determined applying the authors-developed method based on Nelder-Mead technique. The measured forces while plane grinding of test work-piece are used to determine the coefficients. Model coefficients are identified if compare the measured data with the results of modeling for grinding by tool with the uniformly distributed abrasive grains with the triangular shape of cutting edge.Grinding dynamics simulation applying the determined coefficients was carried out for the processing of cantilever plane work-piece as a test example. The work-piece was processed by grinding wheel transverse passages made at different distances from the fixation. A selfoscillating process accompanied by vibration of high level was observed for some selected technological parameters of grinding. The simulation has shown qualitative and quantitative compliance with the experiment. It was shown that the intensity of the self-oscillating process arising during the processing depends on the work-piece rigidity and cutting conditions. The results of modeling can be applied in practice in developing the technology process of grinding the spatial work-pieces.

  8. Investigation on drilling-grinding of CFRP

    Institute of Scientific and Technical Information of China (English)

    Yanming QUAN; Wenwang ZHONG

    2009-01-01

    It is difficult to machine polymer matrix composites reinforced by carbon fibre, and the hole-making process is the most necessary machining process for composite plate products. Conventional drills have a very short life in the drilling of this kind of composites and the quality of the hole is very poor. In this paper, the cemented or plated diamond core tools are tested to make holes in carbon fibre/epoxy composite plates. The effects of machining parameters, cooling and chip removal on the tool life, and the hole quality are investigated. The results indicate that the material removal mechanism of the two kinds of diamond tools is not like the cutting effect of the conventional drilling but similar to that of grinding. Satisfactory effects in making holes in the composites are obtained--quite acceptable machined hole quality, low costs, and long wear-resistant endurance.

  9. Modelling and simulation of fixtures during grinding

    Institute of Scientific and Technical Information of China (English)

    Matthias; KLAERNER; Juergen; LEOPOLD; Lothar; KROLL

    2009-01-01

    The complex workpiece-fixture behaviour during machining is an essential component of the fixture development process.In detail,the forces acting on fixture components have to be analysed.A method for the prediction of the reaction forces due to process and clamping loads is presented in this article.At the beginning,detailed information about the workpiece-fixture behaviour during the process is determined by a complex finite element model.Secondly,the reduction of the number of elements leads to a smaller model with less computation time,validated and used for the variation of process parameters.Finally,an analytical description is developed based on the combination of both results.With the help of the empiric equation it is possible to predict the reaction forces and the dependency on several process parameters.This method has been validated by modelling shape grinding of a nozzle guide vane.

  10. Modelling and simulation of fixtures during grinding

    Institute of Scientific and Technical Information of China (English)

    Matthias KLAERNER; Juergen LEOPOLD; Lothar KROLL

    2009-01-01

    The complex workpiece-fixture behaviour during machining is an essential component of the fixture development process. In detail, the forces acting on fixture components have to be analysed. A method for the prediction of the reaction forces due to process and clamping loads is presented in this article.At the beginning, detailed information about the workpiece-fixture behaviour during the process is determined by a complex finite element model. Secondly, the reduction of the number of elements leads to a smaller model with less computation time, validated and used for the variation of process parameters. Finally, an analytical description is developed based on the combination of both results.With the help of the empiric equation it is possible to predict the reaction forces and the dependency on several process parameters. This method has been validated by modelling shape grinding of a nozzle guide vane.

  11. Continuous grinding mill simulation using Austin's model

    Directory of Open Access Journals (Sweden)

    André Carlos Silva

    2012-01-01

    Full Text Available Comminution is a frequently-required step in mineral processing and is responsible for almost 90% of all energy consumption in a mineral processing plant. Tumbling mill design has been studied since the middle of the XIX century. There are many comminution models in the literature, with preponderance, however, of Austin’s model (2002 for mineral impact breakage. In this paper, Austin’s model was applied to tubular tumbling mills. Once Austin's model was proposed for batch processing of narrowly-distributed fraction sizes, an artifice has allowed it to be used in continuous grinding mill processes with widely-distributed fraction sizes. Interesting results were obtained with errors less than 0.005 for mills with sharp residence time distributions.

  12. Experimental Studies on Ultrasonic Vibration Grinding of the Workpiece Made from Fine-crystalline Zirconia Ceramics

    Institute of Scientific and Technical Information of China (English)

    WU Yan; ZHU Xun-sheng; ZHAO Bo

    2006-01-01

    The performances of fine-crystalline zirconia ceramics in workpiece ultrasonic vibration grinding (WUVG) and conventional grinding (CG) with diamond wheel were researched. The effects of WUVG and CG on material removal rate, grinding forces, surface roughness and microstructure of zirconia ceramic were investigated.Experimental results indicated that: (1) The material removal rate (MRR) in ultrasonic grinding process is two times as large as that of in conventional grinding. The material removal rate increases with increasing grinding depth in both ultrasonic grinding and conventional grinding.(2) The ultrasonic vibration grinding force is lower than that of conventional grinding force, and the increase of the worktable speed leads to a decrease of the grinding force,while the grinding force increases with larger grinding depth in both WUVG and CG. (3) The surface of ultrasonic vibration grinding has no spur and build-up edge and its surface roughness is smaller than that of CG significantly.Surface quality of WUVG is superior to that of conventional grinding, it is easy for ultrasonic vibration grinding that material removal mechanism is ductile grinding.

  13. Grinding temperature and energy ratio coe cient in MQL grinding of high-temperature nickel-base alloy by using di erent vegetable oils as base oil

    Institute of Scientific and Technical Information of China (English)

    Li Benkai; Li Changhe; Zhang Yanbin; Wang Yaogang; Jia Dongzhou; Yang Min

    2016-01-01

    Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM–III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grind-ing temperature, and energy ratio coefficient of MQL grinding were compared among the seven veg-etable oil types. Results revealed that (1) castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient;(2) palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient;(3) MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil;(4) viscosity significantly influences grinding force and grinding tem-perature to a greater extent than fatty acid varieties and contents in vegetable oils;(5) although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less vis-cous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature;(6) saturated fatty acid is a more efficient lubricant than unsaturated fatty acid;and (7) a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force, 87.10 N normal grinding force, 119.6 °C grinding temperature, and 42.7%energy ratio coefficient

  14. Frequency domain identification of grinding stiffness and damping

    Science.gov (United States)

    Leonesio, Marco; Parenti, Paolo; Bianchi, Giacomo

    2017-09-01

    As equivalent stiffness and damping of the grinding process dominate cutting stability, their identification is essential to predict and avoid detrimental chatter occurrence. The identification of these process constants is not easy in large cylindrical grinding machines, e.g. roll grinders, since there are no practical ways to measure cutting force normal component. This paper presents a novel frequency domain approach for identifying these process parameters, exploiting in-process system response, measured via impact testing. This method adopts a sub-structuring approach to couple the wheel-workpiece relative dynamic compliance with a two-dimensional grinding force model that entails both normal and tangential directions. The grinding specific energy and normal force ratio, that determine grinding stiffness and damping, are identified by fitting the closed loop FRF (Frequency Response Function) measured during specific plunge-grinding tests. The fitting quality supports the predictive capability of the model. Eventually, the soundness of the proposed identification procedure is further assessed by comparing the grinding specific energy identified through standard cutting power measurements.

  15. Ultraprecision, high stiffness CNC grinding machines for ductile mode grinding of brittle materials

    Science.gov (United States)

    McKeown, Patrick A.; Carlisle, Keith; Shore, Paul; Read, R. F.

    1990-10-01

    Under certain controlled conditions it is now possible to machine brittle materials such as glasses and ceramics using single or multi-point diamond tools (grinding), so that material is removed by plastic flow, leaving crack-free surfaces. This process is called 'shear' or 'ductile' mode grinding. It represents a major breakthrough in modern manufacturing engineering since it promises to enable: - complex optical components, both transmission and reflecting to be generated by advanced CNC machines with very little (or even zero) subsequent polishing. - complex shaped components such as turbine blades, nozzle guide vanes, etc. to be finish machined after near net shape forming, to high precision in advanced ceramics such as silicon nitride, without inducing micro-cracking and thus lowering ultimate rupture strength and fatigue life. Ductile mode "damage free" grinding occurs when the volume of materials stressed by each grit of the grinding wheel is small enough to yield rather than exhibit brittle fracture, i.e. cracking. In practice, this means maintaining the undeformed chip thickness to below the ductile-brittle transition value; this varies from material to material but is generally in the order of 0.1 pm or 100 nm, (hence the term "nanogrinding" is sometimes used) . Thus the critical factors for operating successfully in the ductile regime are machine system accuracy and dynamic stiffness between each grit and the workpiece. In detail this means: (i) High precision 'truing' of the diamond grits, together with dressing of the wheel bond to ensure adequate ' openness'; (ii) Design and build of the grinding wheel spindle with very high dynamic stiffness; error motions, radial and axial, must be considerably less than 100 nfl. (iii) Design and build of the workpiece carriage motion system with very high dynamic stiffness; error motions, linear or rotary, must be well within 100 nm. (iv) Smooth, rumble-free, high-stiffness servo-drives controlling the motions

  16. McCarter superfinish grinding for silicon -- an update.

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, F.; Khounsary, A.; McCarter, D.; Krasnicki, F.; Tangedahl, M.

    2000-11-03

    A grinding technique, referred to as the McCarter Superfinish, for grinding large size optical components is discussed and certain surface characterization information about flatness and the relative magnitude of the subsurface damage in silicon substrates is reported. The flatness measurements were obtained with a Zygo surface analyzer, and the substrate damage measurements were made by x-ray diffraction and acid etching. Results indicate excellent control of flatness and fine surface finish. X-ray measurements show that the diamond wheels with small particle sizes used in the final phases of the grinding operation renders surfaces with relatively small subsurface damage.

  17. Effect of wet grinding on structural properties of ball clay

    Science.gov (United States)

    Purohit, A.; Hameed, A.; Chander, S.; Nehra, S. P.; Singh, P.; Dhaka, M. S.

    2015-05-01

    In this paper, the effect of wet grinding on structural properties of ball clay is undertaken. The wet grinding treatment was performed employing ball and vibro mills for different time spells of 2, 4, 8 and 16 hours. The structural properties were carried out using X-ray diffraction (XRD). The structure of ground samples is found to be simple cubic. The crystallographic parameters are calculated and slight change in lattice constant, inter planner spacing and particle size is observed with grinding treatment. The results are in agreement with the available literature.

  18. Investigation on the Surface Coating of Grinding Balls

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The surface coating of grinding balls was investigated experimentally. The results show that a coating may form on the surface of grinding balls when Cr or Al powders are subjected to ball grinding. The plastic deformation of the ball surface plays an important role during the coating formation, and the strong binding force between the powders and the balls is a necessary pre-condition. The thickness of coating increases with the plasticity of the powders and the balls. Annealing the balls with coating will result in an obvious diffusion of the elements in the bonding zone of inter-face.

  19. Eco-efficiency of grinding processes and systems

    CERN Document Server

    Winter, Marius

    2016-01-01

    This research monograph aims at presenting an integrated assessment approach to describe, model, evaluate and improve the eco-efficiency of existing and new grinding processes and systems. Various combinations of grinding process parameters and system configurations can be evaluated based on the eco-efficiency. The book presents the novel concept of empirical and physical modeling of technological, economic and environmental impact indicators. This includes the integrated evaluation of different grinding process and system scenarios. The book is a valuable read for research experts and practitioners in the field of eco-efficiency of manufacturing processes but the book may also be beneficial for graduate students.

  20. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Directory of Open Access Journals (Sweden)

    Li Xun

    2015-10-01

    Full Text Available GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 μm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  1. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Institute of Scientific and Technical Information of China (English)

    Li Xun; Ma Shuang; Meng Fanjun

    2015-01-01

    GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 lm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  2. Fundamentals of grinding : surface conditions of ground WC-Co systems

    NARCIS (Netherlands)

    Hegeman, JBJW; De Hosson, JTM; Shulepov, SY; Lousberg, N; de With, G; Brebbia, CA; Kenny, JM

    1999-01-01

    This paper concentrates on the fundamentals of grinding of inorganic materials. A statistical grinding model was developed based on the topography of the grinding wheel. The results of the model are compared with the results of grinding experiments on WC-Co hardmetals. The calculated profiles and me

  3. Innovative grinding wheel design for cost-effective machining of advanced ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Licht, R.H.; Kuo, P.; Liu, S.; Murphy, D.; Picone, J.W.; Ramanath, S.

    2000-05-01

    This Final Report covers the Phase II Innovative Grinding Wheel (IGW) program in which Norton Company successfully developed a novel grinding wheel for cost-effective cylindrical grinding of advanced ceramics. In 1995, Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics using small prototype wheels. The Phase II program was initiated to scale-up the new superabrasive wheel specification to larger diameters, 305-mm to 406-mm, required for most production grinding of cylindrical ceramic parts, and to perform in-house and independent validation grinding tests.

  4. Laser-assisted Grinding Wheel Dressing (Ⅱ)-Experimental Researches

    Institute of Scientific and Technical Information of China (English)

    Ming CHEN; Fanghong SUN; Youngmoon LEE; Seunghan YANG; Jongchan LEE

    2003-01-01

    Most of the mechanical dressing technologies for resin bonded superabrasive grinding wheels are time consumingand costly. Based on the outcomes of the simulations in the previous study, this paper demonstrates the comprehensive researches on the laser-ass

  5. Gemstone Grinding Process Improvement by using Impedance Force Control

    Directory of Open Access Journals (Sweden)

    Hamprommarat Chumpol

    2015-01-01

    Full Text Available Chula Automatic Faceting Machine has been developed by The Advance Manufacturing Research Lab, Chulalongkorn University to support Thailand Gems-Industry. The machine has high precision motion control by using position and force control. A contact stiffness model is used to estimate grinding force. Although polished gems from the Faceting Machine have uniform size and acceptable shape, the force of the grinding and polishing process cannot be maintain constant and has some fluctuation due to indirect force control. Therefor this research work propose a new controller for this process based on an impedance direct force control to improve the gemstone grinding performance during polishing process. The grinding force can be measured through motor current. The results show that the polished gems by using impedance direct force control can maintain uniform size as well as good shape and high quality surface.

  6. Grinding efficiency improvement of hydraulic cylinders parts for mining equipment

    Directory of Open Access Journals (Sweden)

    Korotkov Aleksandr

    2017-01-01

    Full Text Available The aim of the article is to find out ways to improve parts treatment and components of mining equipment on the example of hydraulic cylinders parts, used as pillars for mine roof supports, and other actuator mechanisms. In the course of the research work methods of machine retaining devices design were used, the scientific approaches for the selection of progressive grinding schemes were applied; theoretical and practical experience in the design and production of new constructions of grinding tools was used. As a result of this work it became possible to create a progressive construction of a machine retaining device for grinding of large parts of hydraulic cylinders, to apply an effective scheme of rotary abrasive treatment, to create and implement new design of grinding tools by means of grains with controllable shape and orientation. Implementation of the results obtained in practice will improve the quality and performance of repairing and manufacturing of mining equipment.

  7. E-Records a Grind for Many Doctors

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160789.html E-Records a Grind for Many Doctors And this ... direct contact with patients and 37 percent on E-health records and other clerical work, the study ...

  8. Development of database and searching system for tool grinding

    Directory of Open Access Journals (Sweden)

    J.Y. Chen

    2008-02-01

    Full Text Available Purpose: For achieving the goal of saving time on the tool grinding and design, an efficient method of developing the data management and searching system for the standard cutting tools is proposed in this study.Design/methodology/approach: At first the tool grinding software with open architecture was employed to design and plan grinding processes for seven types of tools. According to the characteristics of tools (e.g. types, diameter, radius and so on, 4802 tool data were established in the relational database. Then, the SQL syntax was utilized to write the searching algorithms, and the human machine interfaces of the searching system for the tool database were developed by C++ Builder.Findings: For grinding a square end mill with two-flute, a half of time on the tool design and the change of production line for grinding other types of tools can be saved by means of our system. More specifically, the efficiency in terms of the approach and retract time was improved up to 40%, and an improvement of approximately 10.6% in the overall machining time can be achieved.Research limitations/implications: In fact, the used tool database in this study only includes some specific tools such as the square end mill. The step drill, taper tools, and special tools can also be taken into account in the database for future research.Practical implications: The most commercial tool grinding software is the modular-based design and use tool shapes to construct the CAM interface. Some limitations on the tool design are undesirable for customers. On the contrary, employing not only the grinding processes to construct the grinding path of tools but the searching system combined with the grinding software, it gives more flexible for one to design new tools.Originality/value: A novel tool database and searching system is presented for tool grinding. Using this system can save time and provide more convenience on designing tools and grinding. In other words, the

  9. Teeth Grinding: Is Emotional Stability related to Bruxism?

    OpenAIRE

    Sutin, Angelina R; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T.

    2010-01-01

    This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral c...

  10. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    OpenAIRE

    2009-01-01

    Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP), which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight) of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in t...

  11. A Path Planning Method for Robotic Belt Surface Grinding

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; YUN Chao

    2011-01-01

    The flexible contact and machining with wide strip are two prominent advantages for the robotic belt grinding system,which can be widely used to improve the surface quality and machining efficiency while finishing the workpieces with sculptured surfaces.There lacks research on grinding path planning with the constraint of curvature.With complicated contact between the contact wheel and the workpiece,the grinding paths for robot can be obtained by the theory of contact kinematics.The grinding process must satisfy the universal demands of the belt grinding technologies,and the most important thing is to make the contact wheel conform to the local geometrical features on the contact area.For the local surfaces with small curvature,the curve length between the neighboring cutting locations becomes longer to ensure processing efficiency.Otherwise,for the local areas with large curvature,the curve length becomes shorter to ensure machining accuracy.A series of planes are created to intersect with the target surface to be ground,and the corresponding sectional profile curves are obtained.For each curve,the curve length between the neighboring cutting points is optimized by inserting a cutter location at the local area with large curvatures.A method of generating the grinding paths including curve length spacing optimization is set up.The validity is completely approved by the off-line simulation,and during the grinding experiments with the method,the quality of surface is improved.The path planning method provides a theoretical support for the smooth and accuracy path of robotic surface grinding.

  12. Development and Performance Evaluation of Maize Threshing and Grinding Machine

    Directory of Open Access Journals (Sweden)

    Ugwu K. C.

    2016-10-01

    Full Text Available The Maize threshing and grinding machine was designed, fabricated and its performance was evaluated. The machine consists of two compartments which include the threshing and grinding chamber. Threshing chamber is where the maize grain is been separated from the cob, and the cob will be collected through the outlet chute. Therefore, before the maize grain enters into the grinding chamber, blower will separate the grain from the chaff. The separated grain enters the grinding chamber and is being grounded by compressive means through the stationary disc and the grinding plate. A 2 hp electric motor provides drive through belt connections to drive the pulley on threshing chamber and another 2 hp electric motor provide drive for the grinding chamber. The actual test was conducted using three different moisture contents and feed rates. It was observed that the efficiency of the machine was hindered by high moisture content. The results obtained showed that the machine performed well at low moisture content. The efficiency of the machine was 99.01% on the moisture content of 10%. The analysis of variance (ANOVA of the results obtained at 5% percent probability confirmed that the moisture content of the maize was an important parameter that affects the performance of the machine

  13. Quenching simulation of steel grinding balls

    Directory of Open Access Journals (Sweden)

    Zapata-Hernández, Oscar

    2015-09-01

    Full Text Available The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses.Las transformaciones de fase en aceros de alto carbono durante su temple y un posterior periodo de estabilización fueron modelizadas por medio del uso de paquetes computacionales basados en el método del elemento finito y de la transformación cinética de los aceros. El modelo se usó para predecir los cambios de temperatura y microestructura que se presentan en bolas de dos diferentes tamaños empleadas en estaciones de molienda de minerales. Se encontró una buena correlación entre las temperaturas medidas mediante la inserción de termopares y aquellas predichas por el modelo una vez que se modificó la conductividad térmica del acero en el intervalo mixto de fases. La predicción de las transformaciones de fase se confirmó a través del análisis metalográfico.

  14. Performance of Cooled Cone Grinding Machine in Cocoa Cake Processing

    Directory of Open Access Journals (Sweden)

    Hendy Firmanto

    2015-08-01

    Full Text Available The process of cocoa paste pressing has a function to separate the fatty component of cocoa from its cake. Cocoa paste is further processed into cocoa powder using grinding machine for cocoa cake. The cooled cone type of cocoa grinding machine is used to solve the problem of plug in the maschine caused by melting of fat in cocoa cake due to hot effect as a result of friction in the grinding machine. Grinding machine of cocoa has conical form of cylinder for grinding and stator wall wrapped by source of cold and closed with jacket wool. Research was conducted at Kaliwining Experimental Garden of Indonesian Coffee and Cocoa Research Institute (ICCRI using cocoa cake containing 26.75% originated from Forastero type of cocoa seed. The capacity and recovery of the machine was influenced by space between rotor cylinder and stator wall. Grinding machine operated at cooling temperature of 25.5oC and space between rotor – stator 0.9 cm and the capacity of 187.5 kg/hour with recovery of 200 mesh cocoa powder as much as 24%. The maximum  power of machine required  was 2.5 kW with efficiency of  energy transfer of 97%. Results of proximate analysis showed that there was no change of protein content, but protein and carbohydrate content increased after processing, i.e. from 5.70% and 59.82% into 5.80% and 61.89% respectively.Key words : cocoa cake, cooling, grinding, cocoa powder 

  15. Research on Stability Prediction of the Crankshaft CNC Tangential Point Tracing Grinding

    Directory of Open Access Journals (Sweden)

    Zhuoda Jiang

    2015-01-01

    Full Text Available As the key part of internal combustion engines, crankshaft with high efficiency and accuracy processing has always been the target of the engine manufacturer’s pursuit. Grinding is used to obtain the ultimate dimensional accuracy and surface finish in the crankshaft machining. Grinding of the main journals and the pin journals can be accomplished in a single clamping operation by CNC Tangential Point Tracing grinding technology. However, the chatter in the grinding process is harmful to the precision and surface quality. In this paper, stability lobe diagram is developed to predict the grinding chatter. First the dynamic model of Tangential Point Tracing grinding system is established. Then the limit formula of the critical grinding depth is calculated and the stability lobe diagram of the grinding system is presented. Finally, the validation experiments are carried out on the crankshaft grinding machine and the results are consistent with the calculation.

  16. Geometrical principium of fewer-axis grinding for large complex optical mirrors

    Institute of Scientific and Technical Information of China (English)

    JIANG; ZhenHua; YIN; YueHong

    2013-01-01

    Ultraprecision grinding is an important approach to efficiently fabricate large complex optical mirrors, and five-axis grinding method is commonly used for ultraprecision grinding. However, this method can hardly meet the high stiffness requirement for grinding large mirror, especially with a diameter over 2 m. Meanwhile, the use of fewer-axis grinding solves this problem, as it reduces the number of the grinder’s axes to improve the rigidity of the system and minimize deformation for hard and brittle materials. But its characteristic of unfixed grinding point which changes with workpiece surface curvature increases geometric complexity and requires a higher geometric shape accuracy of grinding wheel. This paper parameterizes grinding wheel’s geometric shape, reveals the relationship between fewer-axis and five-axis grinding methods from the point of view of the differential geometry, and establishes virtual-axis equivalence principium of feweraxis grinding. A quantitative method to determine grinding wheel’s geometric parameters and its shaft inclination angle is proposed based on the requirements of geometric properties of optical mirror, grinder features and grinding process. Moreover, according to the properties of Gauss curvature of curved surface, the wear law of the toric grinding wheel is found and the surface geometric error distribution due to wear is achieved for fewer-axis grinding. The correctness of the principium and method above are verified through simulations.

  17. STUDIES ON CONTINUOUS GRINDING PROCESS FOR DRIED WATER CHESTNUT KERNEL

    Directory of Open Access Journals (Sweden)

    S.K. GARG

    2010-06-01

    Full Text Available Grinding is a unit operation to break big solid material into smaller pieces. As far as process of grinding is concerned, power consumption, specific energy consumption and particle size distribution and mill capacity are main considerations from engineering point of view. The experiments were conducted to study the effect of speed of mill, sieve size, feed rate and time of grinding on power consumption and average particle diameter of water chestnut in continuous grinding process. Power consumption was measured for a constant feed rate of 1 and 2 kg/h at different speed of the mill varied from 800 to 1200 rpm for the sieve openings of 0.5 mm, 1.0 mm and 2.0 mm. For all the sieve sizes and feed rates, it was observed that as the speed of the mill increases, there is an increase in power consumption and found significantly low for higher sieve size and lower feed rate. The size distribution of the water chestnut kernel for different speeds and sieve sizes at constant feed rate were obtained by sieve analysis. The milling speed has no significant effect on particle size distribution of ground product and mass fraction was minimum at lower feed rate and higher sieve size. Harris model was found best suitable to describe the size distribution in continuous grinding process. Fineness modulus decreases with increase of milling speed for experimental sieve size and feed rate.

  18. Low-Rank Coal Grinding Performance Versus Power Plant Performance

    Energy Technology Data Exchange (ETDEWEB)

    Rajive Ganguli; Sukumar Bandopadhyay

    2008-12-31

    The intent of this project was to demonstrate that Alaskan low-rank coal, which is high in volatile content, need not be ground as fine as bituminous coal (typically low in volatile content) for optimum combustion in power plants. The grind or particle size distribution (PSD), which is quantified by percentage of pulverized coal passing 74 microns (200 mesh), affects the pulverizer throughput in power plants. The finer the grind, the lower the throughput. For a power plant to maintain combustion levels, throughput needs to be high. The problem of particle size is compounded for Alaskan coal since it has a low Hardgrove grindability index (HGI); that is, it is difficult to grind. If the thesis of this project is demonstrated, then Alaskan coal need not be ground to the industry standard, thereby alleviating somewhat the low HGI issue (and, hopefully, furthering the salability of Alaskan coal). This project studied the relationship between PSD and power plant efficiency, emissions, and mill power consumption for low-rank high-volatile-content Alaskan coal. The emissions studied were CO, CO{sub 2}, NO{sub x}, SO{sub 2}, and Hg (only two tests). The tested PSD range was 42 to 81 percent passing 76 microns. Within the tested range, there was very little correlation between PSD and power plant efficiency, CO, NO{sub x}, and SO{sub 2}. Hg emissions were very low and, therefore, did not allow comparison between grind sizes. Mill power consumption was lower for coarser grinds.

  19. Ductile streaks in precision grinding of hard and brittle materials

    Indian Academy of Sciences (India)

    V C Venkatesh; S Izman; S Sharif; T T Mon; M Konneh

    2003-10-01

    Ductile streaks produced during diamond grinding of hard and brittle materials have aided the subsequent process of polishing. Two novel techniques were used to study the formation of ductile mode streaks during diamond grinding (primary process) of germanium, silicon, and glass. In the first technique, aspheric surfaces were generated on Ge and Si at conventional speeds (5000 rpm). In the second technique, diamond grinding of plano surfaces on glass and Si surfaces using high speed (100,000 rpm) was carried out. Form accuracy, surface finish and ductile mode grinding streaks are discussed in this paper. It was found that resinoid diamond wheels gave more ductile streaks than metal-bonded wheels but better form accuracy was obtained with the latter. Ductile streaks were obtained more easily with pyrex rather than with BK 7 glass thus necessitating very little time for polishing. Ductile streaks appeared in abundance on germanium rather than silicon. Both the novel grinding techniques were used on CNC machining centres.

  20. Shape-Grinding by Direct Position/Force Control

    Science.gov (United States)

    Chen, Guanghua; Xu, Weiwei; Minami, Mamoru

    Based on the analysis of the interaction between a manipulator's hand and a working object, a model representing the constrained dynamics of the robot is first discussed. The constrained forces are expressed by an algebraic function of states, input generalized forces, and the constraint condition, and then a direct position/force controller without force sensor is proposed based on the algebraic relation. To give a grinding system the ability to adapt to any object shape being changed by the grinding, we add a function estimating the constraint condition in real time for the adaptive position/force control. Evaluations through simulations, by fitting the changing constraint surface with spline functions, indicate that reliable position/force control and shape-grinding can be achieved by the proposed controller.

  1. Grinding process within vertical roller mills: experiment and simulation

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-huai; CHEN Qing-ru; KUANG Ya-li; LYNCH A J; ZHUO Jin-wu

    2009-01-01

    Based on screening analysis, laser size analysis, grindability and rigidity tests of samples collected on line from a cement and a power plant, a simulation of the grinding process in vertical roller mills was carried out. The simulation calculation used a breakage function, B. The results indicate that the breakage function, B, and the selection function, S, in the form of a matrix, can be used to express the probability of the material breaking during the grinding process. This allows the size distribution of the product to be numerically estimated. The simulation results also show that the simulated size distribution curves fit the actual ex-perimental product curves quite well. The model provides a good starting point for simulation of the grinding process. Further re-search is needed to determine the proper breakage function and the matrix value of the selection function.

  2. Design and experimental study of a micro-groove grinding wheel with spray cooling effect

    Directory of Open Access Journals (Sweden)

    Shi Chaofeng

    2014-04-01

    Full Text Available The effectiveness of grinding fluid supply has a crucial impact on grinding quality and efficiency in high speed grinding. In order to improve the cooling and lubrication, through in-depth research of self-inhaling internal cooling method and intermittent grinding mechanism, a new spray cooling method used in high speed grinding is proposed. By referring to the structure of bowl-shaped dispersion disk, the grinding wheel matrix with atomization ability is designed; through studying heat transfer of droplet collision and the influence of micro-groove on the boiling heat transfer, grinding segment with micro-groove is designed to enhance the heat flux of coolant and achieve maximum heat transfer between droplets and grinding contact zone. High-speed grinding experiments on GH4169 with the developed grinding wheel are carried out. The results show that with the micro-groove grinding wheel just 5.4% of pump outlet flow rate and 0.5% of spindle energy is needed to reduce the grinding temperature to 200 °C, which means the developed grinding wheel makes cooling high efficient and low energy consuming.

  3. High-speed, low-damage grinding of advanced ceramics Phase 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, J.A. [Eaton Corp., Willoughby Hills, OH (United States). Mfg. Technologies Center; Malkin, S. [Univ. of Massachusetts (United States)

    1995-03-01

    In manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. Most of these costs arise from the conventional multi-step grinding process with numerous grinding wheels and additional capital equipment, perishable dressing tools, and labor. In an attempt to reduce structural ceramic grinding costs, a feasibility investigation was undertaken to develop a single step, roughing-finishing process suitable for producing high-quality silicon nitride ceramic parts at high material removal rates at lower cost than traditional, multi-stage grinding. This feasibility study employed combined use of laboratory grinding tests, mathematical grinding models, and characterization of resultant material surface condition. More specifically, this Phase 1 final report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding and the conditions necessary to achieve the small grain depths of cut necessary for low damage grinding while operating at relatively high material removal rates. Particular issues addressed include determining effects of wheel speed and material removal rate on resulting mode of material removal (ductile or brittle fracture), limiting grinding forces, calculation of approximate grinding zone temperatures developed during HSLD grinding, and developing the experimental systems necessary for determining HSLD grinding energy partition relationships. In addition, practical considerations for production utilization of the HSLD process are also discussed.

  4. Robotic Instrument for Grinding Rocks Into Thin Sections (GRITS)

    Science.gov (United States)

    Paulsen, Gale; Zacny, Kris; Dreyer, Christopher B.; Szucs, Attila; Szczesiak, Matt; Santoro, Chris; Craft, Jack; Hedlund, Magnus; Skok, John

    2013-06-01

    We have developed a rock grinding and polishing mechanism for in situ planetary exploration based on abrasive disks, called Grinding Rocks Into Thin Sections (GRITS). Performance characteristics and design considerations of GRITS are presented. GRITS was developed as part of a broader effort to develop an in situ automated rock thin section (ISARTS) instrument. The objective of IS-ARTS was to develop an instrument capable of producing petrographic rock thin sections on a planetary science spacecraft. GRITS may also be useful to other planetary science missions with in situ instruments in which rock surface preparation are necessary.

  5. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    Directory of Open Access Journals (Sweden)

    Daniel Véras Ribeiro

    2009-03-01

    Full Text Available Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP, which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in terms of microstructure (SEM, mechanical strength and capillary water absorption was verified. The results obtained proved very satisfactory for the use of this waste as an additive in magnesium phosphate mortars.

  6. INVESTIGATION OF SURFACE TEMPERATURE IN HIGH-EFFICIENCY DEEP GRINDING

    Institute of Scientific and Technical Information of China (English)

    Zhao Henghua; Cai Guangqi; Jin Tan

    2005-01-01

    A new thermal model with triangular heat flux distribution is given in high-efficiency deep grinding. The mathematical expressions are driven to calculate the surface temperature. The transient behavior of the maximum temperature on contact area is investigated in different grinding conditions with a J-type thermocouple. The maximum contact temperatures measured in different conditions are found to be between 1 000 ℃ and 1 500 ℃ in burn-out conditions. The experiment results show good agreement with the new thermal model.

  7. Graphic presentation of information of acoustic monitoring of stream grinding process

    Directory of Open Access Journals (Sweden)

    N.S. Pryadko

    2012-04-01

    Full Text Available The theoretical and experimental mechanisms of thin grinding the loose materials are analyzed. The relation of the density function of acoustic signal amplitudes of grinding process to the degree of loading the jets by material is established.

  8. Effect of disintegration wave grinding on fractional protein and amino acid composition of chickpea

    Directory of Open Access Journals (Sweden)

    G. O. Magomedov

    2013-01-01

    Full Text Available The study of fractional changes and amino acid composition of proteins in the application of chickpea disintegration wave grinding. Comparative analysis of six varieties of chickpea before and after grinding.

  9. Effects of the grinding process on the preparation and qualities of CWS

    Institute of Scientific and Technical Information of China (English)

    Yuliang Zhang; Guoguang Wu; Xianliang Meng; Zengjie Yun; Frank Shi; Yaqun He; Xiaoqiang Luo

    2011-01-01

    Two different grinding processes were examined to determine the effect grinding has on the quality of a CWS.A series of slurries was prepared from Australian (Au) and Chinese (YZ) coals.Both types of coal were ground by a Chinese (CUMT) and an Australian (JK) grinding process.The performance tests of the prepared CWS showed that fluidity of all slurries was acceptable.The concentration of the CWS from YZ coal ground by the CUMT grinding process was higher than when the JK grinding process was used.The highest concentration was 70.14% in this case.The concentration of the CWS prepared from Au coal by the JK grinding process was higher than when the CUMT grinding process was used.The highest concentration in this case was 70.97%.These differences are caused by the particle size distribution developed during the different grinding processes.

  10. THERMAL AND PHYSICAL FEATURES OF MAGNETIC AND ELECTRIC GRINDING PROCESS OF GAS AND THERMAL PROTECTIVE COATINGS

    OpenAIRE

    N. V. Spiridonov; I. O. Sokorov; M. V. Niaroda

    2008-01-01

    The paper reveals thermal zones of magnetic and electric grinding process. The influence of electric and physical parameters of magnetic and electric grinding on temperature in the zone of gas and thermal protective coatings has been established in the paper.

  11. The effect of grinding on the mechanical behavior of Y-TZP ceramics: A systematic review and meta-analyses.

    Science.gov (United States)

    Pereira, G K R; Fraga, S; Montagner, A F; Soares, F Z M; Kleverlaan, C J; Valandro, L F

    2016-10-01

    The aim of this study was to systematically review the literature to assess the effect of grinding on the mechanical properties, structural stability and superficial characteristics of Y-TZP ceramics. The MEDLINE via PubMed and Web of Science (ISI - Web of Knowledge) electronic databases were searched with included peer-reviewed publications in English language and with no publication year limit. From 342 potentially eligible studies, 73 were selected for full-text analysis, 30 were included in the systematic review with 20 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Statistical analyses were performed using RevMan 5.1, with random effects model, at a significance level of 0.05. A descriptive analysis considering phase transformation, Y-TZP grain size, Vickers hardness, residual stress and aging of all included studies were executed. Four outcomes were considered in the meta-analyses (factor: grinding x as-sintered) in global and subgroups analyses (grinding tool, grit-size and cooling) for flexural strength and roughness (Ra) data. A significant difference (p<0.05) was observed in the global analysis for strength, favoring as-sintered; subgroup analyses revealed that different parameters lead to different effects on strength. In the global analysis for roughness, a significant difference (p<0.05) was observed between conditions, favoring grinding; subgroup analyses revealed that different parameters also lead to different effects on roughness. High heterogeneity was found in some comparisons. Generally grinding promotes decrease in strength and increase in roughness of Y-TZP ceramics. However, the use of a grinding tool that allows greater accuracy of the movement (i.e. contra angle hand-pieces coupled to slowspeed turbines), small grit size (<50μm) and the use of plenty coolant seem to be the main factors to decrease the defect introduction and allow the occurrence of the

  12. A mathematical model for surface roughness of fluidic channels produced by grinding aided electrochemical discharge machining (G-ECDM)

    National Research Council Canada - National Science Library

    V G Ladeesh; R Manu

    2017-01-01

    Grinding aided electrochemical discharge machining is a hybrid technique, which combines the grinding action of an abrasive tool and thermal effects of electrochemical discharges to remove material...

  13. Effect of Grinding Process Parameters on Surface Area Roughness of Glass fibre Reinforced Composite Laminate under Dry and Coolant Environment

    Directory of Open Access Journals (Sweden)

    P. Chockalingam

    2016-04-01

    Full Text Available This paper presents a comparative study on dry and wet grinding of chopped strand mat glass fibre reinforced polymer laminates using an alumina wheel. Investigations were performed to study the impact of the grinding parameters, namely feed, speed, and depth of cut on grinding force ratio and surface area roughness. Effective grinding parameters were sought in this study to maximize grinding force ratio and minimize surface area roughness. Test results show that coolant helped to decrease surface area roughness, but inevitably reduced the grinding force ratio in some cases. These findings lead to economic machining solution for optimum grinding conditions in grinding composite laminates.

  14. Study on Effect of Ultrasonic Vibration on Grinding Force and Surface Quality in Ultrasonic Assisted Micro End Grinding of Silica Glass

    Directory of Open Access Journals (Sweden)

    Zhang Jianhua

    2014-01-01

    Full Text Available Ultrasonic vibration assisted micro end grinding (UAMEG is a promising processing method for micro parts made of hard and brittle materials. First, the influence of ultrasonic assistance on the mechanism of this processing technology is theoretically analyzed. Then, in order to reveal the effects of ultrasonic vibration and grinding parameters on grinding forces and surface quality, contrast grinding tests of silica glass with and without ultrasonic assistance using micro radial electroplated diamond wheel are conducted. The grinding forces are measured using a three-component dynamometer. The surface characteristics are detected using the scanning electron microscope. The experiment results demonstrate that grinding forces are significantly reduced by introducing ultrasonic vibration into conventional micro end grinding (CMEG of silica glass; ultrasonic assistance causes inhibiting effect on variation percentages of tangential grinding force with grinding parameters; ductile machining is easier to be achieved and surface quality is obviously improved due to ultrasonic assistance in UAMEG. Therefore, larger grinding depth and feed rate adopted in UAMEG can lead to the improvement of removal rate and machining efficiency compared with CMEG.

  15. GRINDING OF HARDENED STEELS USING OPTIMIZED COOLING RECTIFICADO DE ACEROS ENDURECIDOS USANDO REFRIGERACIÓN OPTIMIZADA

    Directory of Open Access Journals (Sweden)

    Manoel Cléber de Sampaio Alves

    2008-06-01

    Full Text Available Grinding – the final machining process of a workpiece – requires large amounts of cutting fluids for the lubrication, cooling and removal of chips. These fluids are highly aggressive to the environment. With the technological advances of recent years, the worldwide trend is to produce increasingly sophisticated components with very strict geometric and dimensional tolerances, good surface finish, at low costs, and particularly without damaging the environment. The latter requirement can be achieved by recycling cutting fluids, which is a costly solution, or by drastically reducing the amount of cutting fluids employed in the grinding process. This alternative was investigated here by varying the plunge velocity in the plunge cylindrical grinding of ABNT D6 steel, rationalizing the application of two cutting fluids and using a superabrasive CBN (cubic boron nitride grinding wheel with vitrified binder to evaluate the output parameters of tangential cutting force, acoustic emission, roughness, roundness, tool wear, residual stress and surface integrity, using scanning electron microscopy (SEM to examine the test specimens. The performance of the cutting fluid, grinding wheel and plunge velocity were analyzed to identify the best machining conditions which allowed for a reduction of the cutting fluid volume, reducing the machining time without impairing the geometric and dimensional parameters, and the surface finish and integrity of the machined components.La rectificación, proceso final de fabricación de una pieza, hace uso intenso de fluidos de corte con la finalidad de lubricación, refrigeración y remoción de astillas (imperfecciones. Sin embargo, estos fluidos son extremamente agresivos al medio. Con el avance tecnológico la tendencia mundial es producir piezas cada vez mas sofisticadas, con elevado grado de tolerancia geométrica, dimensional, con buen acabamiento superficial, con bajo costo y, principalmente, sin causar daños al

  16. Investigation of glycerol polymerization in the clinker grinding process

    NARCIS (Netherlands)

    Parvulescu, A.N.; Rossi, M.; Della Pina, C.; Ciriminna, R.; Pagliaro, M.

    2011-01-01

    Concrete production is a large scale process that involves high energy consumption. In order to increase the sustainability of this process, the reduction of energy input is necessary. Bio-glycerol was demonstrated to be a highly efficient renewable-based additive in the grinding process for concret

  17. Contact and Non-contact Measurements of Grinding Pins

    Directory of Open Access Journals (Sweden)

    Magdziak Marek

    2015-01-01

    Full Text Available The paper presents the results of contact and non-contact measurements of external profiles of selected grinding pins. The measurements were conducted in order to choose the appropriate measuring technique in the case of the considered measurement task. In the case of contact measurements the coordinate measuring machine ACCURA II was applied. The used coordinate measuring machine was equipped with the contact scanning probe VAST XT and the Calypso inspection software. Contact coordinate measurements were performed by using of different measurement strategies. The applied strategies included different scanning velocities and distances between measured points. Non-contact measurements were conducted by means of the tool presetter produced by the Mahr company. On the basis of gained results the guidelines concerning measurements of grinding pins were formulated. The measurements of analyzed grinding pins performed by means of the non-contact measuring system are characterized by higher reproducibility than the contact measurements. The low reproducibility of contact measurements may be connected with the inaccuracy of the selected coordinate measuring machine and the measuring probe, the measurement parameters and environmental conditions in the laboratory where the coordinate measuring machine is located. Moreover, the paper presents the possible application of results of conducted investigations. The results of non-contact measurements can be used in the simulation studies of grinding processes. The simulations may reduce the costs of machining processes.

  18. GRINDING OF SHAPED TOOLS ON CNC TOOL GRINDER

    Directory of Open Access Journals (Sweden)

    Ján Kráľ

    2013-03-01

    Full Text Available Worm gears are special gears consisting of a worm wheel and a worm. Worm gears can be produced in different ways, depending on the size of the transmission, the number of courses, the pitch angle of worm profile, the number of units produced, the purpose of application, etc. As cylindrical worm gears we consider the cylindrical worms with globoid gears, globoid worm with globoid worm gear and globoid worm with cylindrical worm gearing. This paper deals with the evolvent worm whose curve of the tooth side in the front plane is evolvent. The production of worm with an optimal profile for optimal meshing conditions is an increasingly frequent focus of worm gear manufacturers. The problem of designing the tool cutting edge can be divided into several steps. This article deals with the problems of optimum design of a tool shape for the production of worms; and the problems of calculating the coordinates of the transition cutting edge shape, and thus the path of grinding wheel for sharpening the tool cutting edge shape are solved. By grinding tool of grinding machine we can complete the worm shape and also sharpen the cutting edges of tools for production of worm surface. The problems of calculation of the coordinates are solved with regard to the functioning of the KON 250 CNC grinding machine logic.

  19. Cobalt exposure in a carbide tip grinding process.

    Science.gov (United States)

    Stebbins, A I; Horstman, S W; Daniell, W E; Atallah, R

    1992-03-01

    Reports relating hard metal disease or nonspecific respiratory symptoms to tungsten or cobalt exposure have been published in the past 20 yr. This report discusses a work site investigation of a small company, employing approximately 50 workers, producing carbide tip saw blades for the woodworking industry. Cobalt exposure was characterized by ambient air monitoring (area and personnel), particle size determination, and biological monitoring. Area sampling for cadmium, cobalt, and tungsten indicated low ambient air levels in all manufacturing areas except the grinding department, which had cobalt air levels approaching the threshold limit value of 0.05 mg/m3. Area airborne cobalt exposure levels measured over six shifts in the grinding department ranged from 0.017 to 0.12 mg/m3 for the total collection method and 0.002 to 0.028 mg/m3 for the method collecting respirable particles. Cobalt content in the total and respirable fractions was similar. Urine monitoring indicated production workers have elevated cobalt levels, and the grinders' levels were higher than other production workers. The grinding coolant was found to have elevated cobalt concentrations. A survey of coolants from nine carbide grinding shops indicated the elevated cobalt concentrations may be common.

  20. The Graduate Grind: A Critical Look at Graduate Education

    Directory of Open Access Journals (Sweden)

    Michelle K. McGinn

    2010-05-01

    Full Text Available Abandonment, abuse, anxiety, betrayal, bitterness, breaking point, burnout, collapse, danger, death, desperation, discouragement, divorce, exhaustion, frustration, grind, hardships, hazing, hurdles, ignorance, impossible dream, isolation, killing the spirit, leaving, loneliness, murder, neglect, peril, ridicule, ritual, self-protection, sexual harassment, shock, snobbery, strain, strangulation, stress, suffering, suicide, survival of the fittest, trauma, and violence.

  1. Grinding analysis of Indian coal using response surface methodology

    Institute of Scientific and Technical Information of China (English)

    Twinkle Singh; Aishwarya Awasthi; Pranjal Tripathi; Shina Gautam; Alok Gautam

    2016-01-01

    The present work discusses a systematic approach to model grinding parameters of coal in a ball mill.A three level Box-Behnken design combined with response surface methodology using second order model was applied to the experiments done according to the model requirement.Three parameters ball charge (numbers 10-20),coal content (100-200 g) and the grinding time (4-8 min) were chosen for the experiments as well as for the modeling work.Coal fineness is defined as the d80 (80 % passing size).A quadratic model was developed to show the effect of parameters and their interaction with fineness of the product.Three different sizes (4,1 and 0.65 mm) of Indian coal were used.The model equations for each fraction were developed and different sets of experiments were performed.The predicted values of the fineness of coal were in good agreement with the experimental results (R2 values of d80 varies between 0.97 and 0.99).Fine size of three different coal sizes were obtained with larger ball charge with less grinding time and less solid content.This work represents the efficient use of response surface methodology and the Box-Behnken design use for grinding of Indian coal.

  2. Microstructure studies of the grinding damage in monocrystalline silicon wafers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yinxia; KANG Renke; GUO Dongming; JIN Zhuji

    2007-01-01

    The depth and nature of the subsurface damage in a silicon wafer will limit the performance of IC components.Damage microstructures of the silicon wafers ground by the #325,#600, and #2000 grinding wheels was analyzed.The results show that many microcracks,fractures, and dislocation rosettes appear in the surface and subsurface of the wafer ground by the #325 grinding wheel.No obvious microstructure change exists.The amorphous layer with a thickness of about 100 nm,microcracks, high density dislocations,and polycrystalline silicon are observed in the subsurface of the wafer ground by the #600 grinding wheel.For the wafer ground by the #2000 grinding wheel,an amorphous layer of about 30 nm thickness,a polycrystalline silicon layer,a few dislocations,and an elastic deformation layer exist.In general,with the decrease in grit size,the material removal mode changes from micro-fracture mode to ductile mode gradually.

  3. Facial lesions in piglets with intact or grinded teeth

    Directory of Open Access Journals (Sweden)

    Hansson Monica

    2012-04-01

    Full Text Available Abstract Background Piglets are born with eight sharp teeth that during nursing can cause facial lesions on littermates and teat lesions on the sow. Teeth grinding in piglets is therefore often practiced to reduce these lesions. The aim of this study was to assess the consequences of grinding piglet teeth in regard to the occurrence of lesions. In this study the piglets' teeth were grinded in 28 litters, and in 36 litters the piglets' teeth were kept intact. Twice, one time during the first week and one time during the second week after birth facial lesions of the piglets were scored and the teats of the sows were examined for lesions. The facial lesion score accounted for the amount and severity of lesions. The individual observations on piglets in the litter were synthesized in a litter facial lesion score. Findings 69.8% and 43.5% of the piglets had facial lesions in week 1 and week 2 respectively. The effect of treatment was not significant on litter facial lesion score. The litter facial lesion score was higher in week 1 than in week 2 (p p = 0.003 than in small litters. Mortality between week 1 and week 2 was higher in litters with intact teeth (p = 0.02. Sow teat lesions only occurred if litters had intact teeth. Conclusions According to our results teeth grinding is only justifiable in large litters.

  4. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    Energy Technology Data Exchange (ETDEWEB)

    Poffo, C.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.b [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Souza, S.M.; Triches, D.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Grandi, T.A. [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Biasi, R.S. de [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)

    2011-04-01

    Mechanical grinding (MG) was used to produce nanocrystalline silicon and its thermal and transport properties were investigated by photoacoustic absorption spectroscopy (PAS). The experimental results suggest that in as-milled nanocrystalline silicon for 10 h the heat transfer through the crystalline and interfacial components is similar, and after annealed at 470 {sup o}C the heat transfer is controlled by crystalline component.

  5. [{sup 11}C]-methyl 4-[(3,4-dichlorophenyl)acetyl]-3-[(1-pyrrolidinyl)methyl] -1-piperazinecarboxylate ([{sup 11}C]GR89696): synthesis and in vivo binding to kappa opiate receptors

    Energy Technology Data Exchange (ETDEWEB)

    Ravert, Hayden T.; Mathews, William B.; Musachio, John L.; Scheffel, Ursula; Finley, Paige; Dannals, Robert F

    1999-10-01

    GR89696, racemic methyl 4-[(3,4-dichlorophenyl)acetyl]-3-[(1-pyrrolidinyl) methyl] -1-piperazinecarboxylate, a kappa opioid receptor ligand, was labeled with [{sup 11}C]methyl chloroformate. The radiochemical yield was 20% with an observed specific radioactivity of 75.5 GBq/{mu}mol at end of synthesis (2,040 mCi/{mu}mol). Five minutes after intravenous administration, 5.4% of the injected dose accumulated in mouse whole brain. Brain region to cerebellar ratios increased over time with ratios at 90 min of 7.8, 5.6, and 4.5 for the hypothalamus, olfactory tubercle, and striatum, respectively. The uptake of [{sup 11}C]GR89696 correlated with known kappa opioid receptor densities and was inhibited by kappa opioid selective drugs.

  6. Effect of LIF-withdrawal on acetylcholine synthesis in the embryonic stem cell line CGR8 is not mediated by STAT3, PI3Ks or cAMP/PKA pathways.

    Science.gov (United States)

    Michel-Schmidt, Rosmarie; Kirkpatrick, Charles James; Wessler, Ignaz

    2015-11-01

    Acetylcholine (ACh) acts as a local cellular signaling molecule and is widely expressed in nature, including mammalian cells and embryonic stem cells. The murine embryonic stem cell line CGR8 synthesizes and releases substantial amounts of ACh. Particularly during early differentiation - a period associated with multiple alterations in geno-/phenotype functions - synthesis and release of ACh are increased by 10-fold. In murine stem cells second messengers of the STAT-3, PI3K and cAMP/PKA pathways are involved in maintaining self-renewal and pluripotency. The present experiments were designed to test whether blockers of these signaling pathways enhance ACh cell content in the presence of LIF, i.e. when CGR8 is pluripotent. NSC74859, an inhibitor of STAT-3, affected neither the proliferation rate nor ACh cell content, whereas the more sensitive STAT-3 inhibitor FLLL31 reduced the proliferation rate and increased ACh cell content by about 3-fold. The PI3K inhibitor LY294002 reduced the proliferation rate but did not modify the ACh cell content, whereas the PKA inhibitor H89 produced effects comparable to FLLL31. Interestingly, in control experiments a strong inverse correlation was found between cell density and ACh cell content, which could explain the 3-fold increase in the ACh cell content observed in the presence of FLLL31 and H89. Forskolin, a PKA activator, had no effect. In conclusion, it appears unlikely that the 10-fold increase in ACh cell content induced by LIF removal, i.e. during early differentiation, is mediated by second messengers of the STAT-3, PI3K and cAMP/PKA pathways. However, the PI3K pathway appears to be involved in control of the inverse relation between cell density and ACh cell content, because this correlation was significantly attenuated in the presence of LY294002.

  7. Development of ELID mirror surface grinding by cast iron bond grinding wheel. Ohkochi memorial technology prize; Chutetsu bond toishi ni yoru denkai inpurosesu doresshingu (ELID) kyomen kensakuho no kaihatsu. Okochi kinen gijutsusho jusho ni yosete

    Energy Technology Data Exchange (ETDEWEB)

    Omori, H.; Takahashi, I. [Institute of Physical and Chemical Research, Tokyo (Japan); Nakagawa, T. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Hagiuda, Y.; Karikome, K. [Tokyo Metropolitan College of Aeronautical Engineering, Tokyo (Japan)

    1997-08-01

    Development was accomplished on the electrolytic in-process dressing (ELID) mirror surface grinding process using a cast iron bonded grinding wheel. This paper describes the history of the development, which may be summarized as follows: a study was begun on powder forging of cutting chips in 1970; a research was started on powder forging of decarburized cast iron powder; developments were made on powder metallurgy of cast irons and cast iron bonded lapping tools in 1980, and cast iron bonded diamond grinding wheels were put on the market; a high-efficiency grinding process using MC and cast iron fiber-bonded grinding wheels were developed in 1985 and the grinding wheels made therefrom were put on the market; and a study was begun on the ELID grinding in 1987, and marketing was started on power supply, grinding liquid and tools for the ELID grinding process in 1990. Discussions on converting raw materials for the powder forging into cutting chips have triggered developing the cast iron bonded grinding wheel. The cast iron bonded diamond grinding wheel improves dressability and sharpness of conventional grinding wheels. The grinding wheel is fabricated by mixing carbonyl iron powder, diamond grinding grains and cast iron powder, pressing the mixture in a die, sintering it at 1140 degC, and assembling and dressing the sinter. The grinding stone can grind high-tech materials. 4 figs.

  8. A 6-DOF parallel bone-grinding robot for cervical disc replacement surgery.

    Science.gov (United States)

    Tian, Heqiang; Wang, Chenchen; Dang, Xiaoqing; Sun, Lining

    2017-05-24

    Artificial cervical disc replacement surgery has become an effective and main treatment method for cervical disease, which has become a more common and serious problem for people with sedentary work. To improve cervical disc replacement surgery significantly, a 6-DOF parallel bone-grinding robot is developed for cervical bone-grinding by image navigation and surgical plan. The bone-grinding robot including mechanical design and low level control is designed. The bone-grinding robot navigation is realized by optical positioning with spatial registration coordinate system defined. And a parametric robot bone-grinding plan and high level control have been developed for plane grinding for cervical top endplate and tail endplate grinding by a cylindrical grinding drill and spherical grinding for two articular surfaces of bones by a ball grinding drill. Finally, the surgical flow for a robot-assisted cervical disc replacement surgery procedure is present. The final experiments results verified the key technologies and performance of the robot-assisted surgery system concept excellently, which points out a promising clinical application with higher operability. Finally, study innovations, study limitations, and future works of this present study are discussed, and conclusions of this paper are also summarized further. This bone-grinding robot is still in the initial stage, and there are many problems to be solved from a clinical point of view. Moreover, the technique is promising and can give a good support for surgeons in future clinical work.

  9. Research on the Monitoring System of CNC Grinding Process Based on Acoustic Emission

    Institute of Scientific and Technical Information of China (English)

    HU Zhongxiang; TENG Jiaxu; YANG Junwei; HUO Xiaojing; SHI Xiaojun

    2006-01-01

    Using on-line monitoring during the CNC grinding process, the hazard case such as the crushing of grinding wheel and various safety accidents could be avoided, and the optimum time for dressing and replacing grinding wheel could also be determined, and hence, the service life of the grinding wheel could be prolonged and grinding quality could be improved. To overcome the limitation of some traditional techniques in which some parameters including the grinding power and force, torque and so on were monitored, the acoustic emission (AE) technique, which provides high sensitivity and responding speed, were developed in the present paper. The mechanism of AE during grinding was reviewed. Moreover, a virtual AE monitoring system, which could monitor the grinding state under different working conditions during the grinding, has been developed based on the Virtual Instruments technique. Some experiments were also performed on the internal grinder. The results showed that the AE signals became stronger with increasing the main shaft speed and grinding depth or decreasing the distance between the AE sensor and grinding area.

  10. Experimental investigation of abrasive electrodischarge grinding of Ti6Al4V titanium alloy

    Directory of Open Access Journals (Sweden)

    R. Święcik

    2009-12-01

    Full Text Available Purpose: This work is focused on determination of effects of grinding conditions on effectiveness of abrasive electrodischarge grinding (AEDG process applied for removal of machining allowance and forming of surface geometrical texture (SGT. These results were compared with one obtained for conventional grinding.Design/methodology/approach: The experimental investigations of deep-seated surface grinding of Ti6Al4V titanium alloy using CBN grinding wheel with metal bond were the ground for this elaboration. The effectiveness of AEDG process was assessed based on specific tangential grinding force and energy of spark electric discharge and machining results were estimated on geometrical structure parameters.Findings: The effectiveness of machining allowance removal depended on conditions of AEDG process. Significant differences in SGT formed by AEDG process and conventional grinding were revealed.Practical implications: Abrasive electrodischarge grinding is useful to be particularly suitable for efficient and effective grinding of very hard structural materials such as high-alloy steel, sintered carbides, metal-based composite materials etc.Originality/value: AEDG experiments were carried out using the typical surface finishing grinder and especially adapted generator of spark discharge pulses. The majority of such experiments in the world were performed with the electrodischarge machine tool equipped with extra grinding wheel mounted on the grinding pin and functioning as one of the electrodes put into operation via pneumatic drive.

  11. Research into Grinding Hardening of Microalloyed Non-quenched and Tempered Steel

    Institute of Scientific and Technical Information of China (English)

    HAN Zheng-tong; ZHANG Ning-ju; GAO Ding; YANG Gang

    2007-01-01

    Grinding hardening is a new technology of hardening steel piece surfaces with grinding heat generated in the grinding process instead of with a high or medium frequency induction heating method, which can effectively integrate grinding and surface hardening. Experimental studies were carried out on grinding hardening of non-quenched and tempered steel. Through grinding experiments with variable depths of cut and feeding rate, the variation in the depth of the hardening layer was studied and the microstructure of the hardening zone of the test pieces was subsequently analyzed. In the end, the hardening effect of non-quenched and tempered steel was compared with that of 40Cr steel, which revealed the superiority of non-quenched and tempered steel in grinding hardening technology.

  12. Development of a grinding-specific performance test set-up

    DEFF Research Database (Denmark)

    Olesen, C. G.; Larsen, B. H.; Andresen, E. L.

    2015-01-01

    and an exponentially rising resistance. A custom-made grinding ergometer was developed with computer-controlled resistance and capable of collecting data during the test. The data collected can be used to find measures of grinding performance such as peak power, time to complete and the decline in repeated grinding......The aim of this study was to develop a performance test set-up for America's Cup grinders. The test set-up had to mimic the on-boat grinding activity and be capable of collecting data for analysis and evaluation of grinding performance. This study included a literature-based analysis of grinding...... demands and a test protocol developed to accommodate the necessary physiological loads. This study resulted in a test protocol consisting of 10 intervals of 20 revolutions each interspersed with active resting periods of 50 s. The 20 revolutions are a combination of both forward and backward grinding...

  13. Fine grinding of brittle minerals and materials by jet mill

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2008-05-01

    Full Text Available Various variables affecting grinding, such as air pressure, minerals or materials hardness, feed size were investigated.The limitations of grinding of gypsum, barite, ilmenite, quartz and ferrosilicon were also elucidated by means of particlefineness size distribution and morphology of ground products. It was found that:1 The density of particles, which are in the grinding zone affects the product fineness, i.e. higher feed rate resultsin a larger product size. The appropriate feed rate is suggested to be 0.2~0.5 g/s. Moreover, the density and hardness ofminerals or materials tend to have an effect on the product fineness. Heavy minerals, such as barite or ilmenite, exhibit afiner product size than lighter minerals, like quartz. However, for quartz, the higher hardness also results in a larger d50.2 Air pressure is the most vital variable which affects the grinding by a jet mill. The d50 seems to relate to theapplied air pressure as a power law equation expressed as following:d50 = aP b ; as P 0The a-value and b-value have been found to correlate to the feed size. The higher the air pressure applied the finerthe product size attained. Moreover, air pressure has a greater effect on hard minerals than on softer ones.3 Feed size seems to have a small effect on ground the product fineness of soft materials, such as gypsum andbarite, but a significant effect on that of hard materials, such as ferrosilicon and quartz, in particularly by milling at low airpressures of 2~3 kg/cm2.4 For the breakage behavior and morphology of ground materials, it was also found that the minerals having cleavages,such as gypsum and barite, tend to be broken along their cleavage planes. Thus, the particle size distribution of theseproducts becomes narrower. While quartz, ilmenite, and ferrosilicon have shattering and chipping breakage mechanisms,grinding results in angular shapes of the ground products and a wider size distribution. Blocks or platelets and

  14. Teeth Grinding: Is Emotional Stability related to Bruxism?

    Science.gov (United States)

    Sutin, Angelina R.; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T.

    2010-01-01

    This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral complaints often associated with anxiety (jaw clicks, difficulty chewing food, and dry mouth), but not with more general oral health complaints (unhealthy gums, bleeding gums, and canker sores) or with dentist-assessed occlusal wear or tongue indentations. This study provides evidence for the association between Neuroticism and bruxism and other stress-related oral health symptoms. PMID:20835403

  15. Repair grinding -- An alternative to ultrasonic rejection for oilfield tubes

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, R.K. (NDE Information Consultants, Houston, TX (United States))

    1994-10-01

    The price of scrap steel rose from $95 to $140/ton in 1993, making tubular production costs higher and making internal repair grinding of oil field tubes with minor internal surface breaking imperfections an extremely cost effective method for placing potentially reject tubulars back into service. Such imperfections often occur and are presently sized by the shear wave ultrasonic amplitude method. This article is written to illustrate how effective repair grinding can be in producing prime material within the API specifications 5CT, specification for Casing and Tubing; 5D, Specification for Drill Pipe; and 5L, Line Pipe. Ninety percent of high grade and 50--60% of midgrade materials can be saved by this method.

  16. Teeth Grinding: Is Emotional Stability related to Bruxism?

    Science.gov (United States)

    Sutin, Angelina R; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T

    2010-06-01

    This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral complaints often associated with anxiety (jaw clicks, difficulty chewing food, and dry mouth), but not with more general oral health complaints (unhealthy gums, bleeding gums, and canker sores) or with dentist-assessed occlusal wear or tongue indentations. This study provides evidence for the association between Neuroticism and bruxism and other stress-related oral health symptoms.

  17. Efficient Fuel Pretreatment: Simultaneous Torrefaction and Grinding of Biomass

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Hansen, Brian Brun; Jensen, Peter Arendt

    2013-01-01

    Combining torrefaction and grinding of biomass in one reactor may be an attractive fuel pretreatment process. A combined laboratory torrefaction and ball mill reactor has been constructed for studies of the influence of temperature and residence time on the product yields and particle size......, and ash composition, where straw has a higher alkali content. This and other studies indicate that the large difference in the alkali contents of the biomasses is the main cause for the observed difference in torrefaction characteristics. Experiments with separate particle heating and grinding showed...... of straw for 90 min yielded a higher mass loss (27–60 wt %) and relative size reduction (59–95%) compared with spruce (mass loss of 10–56 wt % and size reduction of 20–60%). The two types of biomass investigated differ with respect to hemicellulose type, lignocellulosic composition, particle morphology...

  18. Study of CNC Grinding Machining Method About Isometric Polygon Profile

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The formed principle and CNC grinding machining method of isometric polygonal profile are studied deeply and systematically. Equation about section curve of isometric polygon profile is set up by means of geometric principle. With the use of differential geometry theory, the curve is proved to be with geometric feature of convex curve. It is referred to as Isometric Polygonal Curve (IPC), because that is a kind of convex curve on which the distance between any parallel tangent lines is equal. Isometric Poly...

  19. Respiratory Diseases in Agate Grinding Workers in Iran

    Directory of Open Access Journals (Sweden)

    E Rafeemanesh

    2014-07-01

    Full Text Available Background: Agate is a hard silica stone with bands of various colors, which is used in jewelry. The agate grinding workers are exposed to silica dust.Objective: To determine the prevalence of respiratory diseases in agate grinding workers and the associated factors.Methods: In this cross-sectional study, 170 agate grinding workers from Mashhad, northeastern Iran, were examined. Medical and occupational history for respiratory illnesses was taken using respiratory questionnaire of the national program of silicosis control, lung examination, spirometry and chest radiography. Chest x-rays were interpreted according to the International Labor Office (ILO classification system, 2000.Results: The mean±SD of age and work duration of the participants were 31.2±10.1 and 13±8.2 years, respectively. The prevalence of silicosis among agate workers was 12.9% (95% CI: 7.9%–18.0%; 18 workers had simple and 4 had complicated silicosis. There was a significant (p<0.05 relationship between contracting silicosis and exposure duration. 20 (11.7% workers had symptoms consistent with chronic bronchitis and 8 (4.7% showed asthma and asthma-like symptoms. The most frequent disorder observed in spirometry was the restrictive pattern (n=43, 30%. In the agate grinders, clinical and spirometry findings did not match with radiological findings.Conclusion: Agate grinding workers are at increased risk for respiratory diseases, specifically for silicosis and chronic bronchitis. The disease is related to silica dust exposure, poor ventilation and inappropriate personal protection.

  20. FRACTURE FEATURES OF METAL BINDING WHEN DIAMOND-SPARK GRINDING

    Directory of Open Access Journals (Sweden)

    Yury GUTSALENKO

    2012-05-01

    Full Text Available The hypothesis of the influence of binding energy of metal on the processes of destruction and mass transfer at high-speed machining is considered. Some nonconventional processes of cleaning of intergranularity spaces from waste products at diamond-spark grinding are explained, the approach to assessment of metal resistance in these processes is proposed and eo ipso modern conception of processes in chip formation zone under condition of electric discharge effect is supplemented

  1. Grinding induced martensite on the surface of rails

    DEFF Research Database (Denmark)

    Rasmussen, C.J.; Zhang, Xiaodan; Danielsen, Hilmar Kjartansson

    2014-01-01

    determined. Two different rail types R260 and R350HT that both had been ground by a grinding train were investigated. The rail sections, studied using optical and scanning electron microscopy, showed that the surface of both types of rails is covered with WELs. The hardness of the WEL is increased compared...... to the base material and the microstructural investigations reveal that a martensitic structure is present at the surface....

  2. Poly(ethylene glycols as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

    Directory of Open Access Journals (Sweden)

    Andrea Mascitti

    2017-01-01

    Full Text Available The mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins was investigated in the presence of various poly(ethylene glycols (PEGs, as safe grinding assisting agents (liquid-assisted grinding, LAG. A comparative study under dry-grinding conditions was also performed. The results showed that the cyclization reaction was influenced by the amount of the PEG grinding agents. In general, cleaner reaction profiles were observed in the presence of PEGs, compared to dry-grinding procedures.

  3. Can seeds help mice with the daily grind?

    Science.gov (United States)

    Pritchett-Corning, K R; Keefe, R; Garner, J P; Gaskill, B N

    2013-10-01

    Some laboratory mice gnaw food pellets without ingesting much of the gnawed material, resulting in the production of waste material called 'orts'. The fact that this food grinding behavior is not seen in all individuals of a particular strain suggests that it might be abnormal, and thus indicate a welfare concern. Furthermore, the increased rate of feed consumption and cage soiling is undesirable from a husbandry perspective. To try to determine possible motivations for the behavior, and identify potential treatments, outbred Crl:CD1(Icr) mice exhibiting food grinding were selected for one of three treatments placed in the feeder: no enrichment, a chewing device, or sunflower seeds. Both enrichment groups showed a significant decrease (P food wastage after the treatment was withdrawn. A relationship between body weight and ort production was also found, in that cages with greater average body weights had lower levels of ort production. This suggests that a simple need to gnaw cannot alone explain food grinding, and that a nutritional motivation may also be involved.

  4. Rotary ultrasonic machining of CFRP: A comparison with grinding.

    Science.gov (United States)

    Ning, F D; Cong, W L; Pei, Z J; Treadwell, C

    2016-03-01

    Carbon fiber reinforced plastic (CFRP) composites have been intensively used in various industries due to their superior properties. In aircraft and aerospace industry, a large number of holes are required to be drilled into CFRP components at final stage for aircraft assembling. There are two major types of methods for hole making of CFRP composites in industry, twist drilling and its derived multi-points machining methods, and grinding and its related methods. The first type of methods are commonly used in hole making of CFRP composites. However, in recent years, rotary ultrasonic machining (RUM), a hybrid machining process combining ultrasonic machining and grinding, has also been successfully used in drilling of CFRP composites. It has been shown that RUM is superior to twist drilling in many aspects. However, there are no reported investigations on comparisons between RUM and grinding in drilling of CFRP. In this paper, these two drilling methods are compared in five aspects, including cutting force, torque, surface roughness, hole diameter, and material removal rate.

  5. Physical characterization of coffee after roasting and grinding

    Directory of Open Access Journals (Sweden)

    Gabriel Henrique Horta de Oliveira

    2014-09-01

    Full Text Available Flowability is an important characteristic of handling process for efficiency and reliability purpose of post-harvest operations, which are governed by the physical properties of the product. Physical properties determination is an important factor for formulation of machinery projects and sizing of post-harvest operations, which may impact considerably on the products quality, influencing directly the operation cost and company profit. Thus, the objective of this work was to evaluate and determinate some physical properties (repose angle, unit and bulk density, porosity and color coordinates, particle size, moisture content, water activity, angle of internal friction and effective angle of internal friction of coffee, such as to evaluate the influence of different roast and grinding degrees over these properties. Crude grain coffee (Coffea canephora and Coffea arabica, dehulled and dried were used. These were roasted at two levels: medium light and medium-dark brown, which Agtron numbers are, respectively, SCAA#65 and SCAA#45. After roasting process, grains were grinded at three particle sizes (thin, medium and thick. Both particle size and roast degree significantly affected physical properties of coffee. Coffee samples roasted at medium dark level obtained lower values of moisture content, water activity, repose angle, bulk and real density. Coffee samples grinded at level thin presented an increase of angle of internal friction and effective angle of internal friction, repose angle, bulk and real density, porosity and decrease of water activity values.

  6. Thermal Aging Effects on Residual Stress and Residual Strain Distribution on Heat Affected Zone of Alloy 600 in Dissimilar Metal Weld

    Energy Technology Data Exchange (ETDEWEB)

    Ham, Junhyuk; Choi, Kyoung Joon; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

    2016-10-15

    Dissimilar metal weld (DMW), consisting of Alloy 600, Alloy 182, and A508 Gr.3, has been widely used as a joining material of the reactor pressure vessel penetration nozzle and the steam generator tubing for pressurized water reactors (PWR) because of its good mechanical strength, thermal conductivity, and corrosion resistance. Residual tensile stress is mainly nominated as a cause of SCC in light water reactors by IAEA report. So, to relax the residual stress, post-weld heat treatment is required after manufacturing process such as welding. However, thermal treatment has a great effect on the microstructure and the chromium depletion profile on Alloy 600, so called sensitization. By this reason, HAZ on Alloy 600 is critical to crack. According to G.A. Young et al., Crack growth rates (CGR) in the Alloy 600 HAZ were about 30 times faster than those in the Alloy 600 base metal tested under the same conditions. And according to Z.P. Lu et al., CGR in the Alloy 600 HAZ can be more than 20 times higher than that in its base metal. There are some methods to measure the exact value of residual stress on the material surface. The most common way is X-ray diffraction method (XRD). The principle of XRD is based on lattice strains and depends on the changes in the spacing of the atomic planes in material. And there is a computer simulation method to estimate residual stress distribution which is called ANSYS. This study was conducted to investigate how thermal aging affects residual stress and residual strain distribution of Alloy 600 HAZ. Following conclusions can be drawn from this study. According to preceding researches and this study, both the relaxation of residual stress and the change of residual strain follow as similar way, spreading out from concentrated region. The result of Vickers micro-hardness tester shows that tensile residual stresses are distributed broadly on the material aged by 15 years. Therefore, HT400{sub Y}15 material is weakest state for PWSCC. The

  7. Teeth grinding, oral motor performance and maximal bite force in cerebral palsy children.

    Science.gov (United States)

    Botti Rodrigues Santos, Maria Teresa; Duarte Ferreira, Maria Cristina; de Oliveira Guaré, Renata; Guimarães, Antonio Sergio; Lira Ortega, Adriana

    2015-01-01

    Identify whether the degree of oral motor performance is related to the presence of teeth grinding and maximal bite force values in children with spastic cerebral palsy. Ninety-five spastic cerebral palsy children with and without teeth grinding, according to caregivers' reports, were submitted to a comprehensive oral motor performance evaluation during the feeding process using the Oral Motor Assessment Scale. Maximal bite force was measured using an electronic gnathodynamometer. The teeth grinding group (n = 42) was younger, used anticonvulsant drugs, and was more frequently classified within the subfunctional oral motor performance category. Teeth grinding subfunctional spastic cerebral palsy children presented lower values of maximal bite force. The functional groups showing the presence or absence of teeth grinding presented higher values of maximal bite force compared with the subfunctional groups. In spastic cerebral palsy children, teeth grinding is associated with the worse oral motor performance. © 2015 Special Care Dentistry Association and Wiley Periodicals, Inc.

  8. A Review: The Effect of Grinded Coal Bottom Ash on Concrete

    Directory of Open Access Journals (Sweden)

    Basirun Nurul Fasihah

    2017-01-01

    Full Text Available This paper offers a review on the use of grinded coal bottom ash (CBA on the concrete properties as demonstrated by strength test and microstructure test. Amount of CBA from power plant station was disposed in landfill because of the particle shape had a rough particles. By finding an alternative way to gain its surface area by grinding and used as replacement material as cement replacement may give a good side feedback on the strength and morphology of concrete. Most of the prior works studied on the grinded fly ash and grinded rice husk ash. The study on the influence of grinded CBA on the properties of concrete still limited and need more attention Therefore, the review on the effect of grinded CBA on the strength and microstructure of concrete are discussed.

  9. Effect of Grinding Temperatures on the Surface Integrity of a Nickel-based Superalloy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An experimental study was carried out to investigat e the influence of temperatures on workpiece surface integrity in surface grinding of a cast nickel-based superalloy with alumina abrasive wheels. Temperatur e response at the wheel-workpiece interface was measured using a grindable foil /workpiece thermocouple. Specimens with different grinding temperatures were obt ained through changing grinding conditions including depth of cut, workpiece fee d speed, and coolant supply. Changes in surface roughnes...

  10. Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding

    OpenAIRE

    2011-01-01

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e., piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to ...

  11. ELECTRO-RESISTANCE METHOD OF CHECK A PROCESS GRINDING THE ROLLING BEARINGS

    Directory of Open Access Journals (Sweden)

    K. V. Podmasteryev

    2015-01-01

    Full Text Available Base a possibility of monitoring processes of grinding the rolling bearings with use electroresistance method of check. Is write of essence this method, are analyses his peculiarities, which are provide objective information on the condition a object by his grinding. Are consider the results of experimental researches the effective different diagnostically parameters, which are confirm a possibility of realization objective check of grinding the rolling bearings with use electro-resistance method.

  12. The Simulation of Grinding Wheels and Ground Surface Roughness Based on Virtual Reality Technology

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper describes the feasibility and method of the application of virtual reality technology to grinding process, and introduces the modeling method of object entity in the environment of virtual reality. The simulation process of grinding wheels and ground surface roughness is discussed, and the computation program system of numerical simulation is compiled with Visual C++ programming language. At the same time, the three-dimensional simulation models of grinding wheels and ground surface roughness are ...

  13. Optimization of Preventive Grinding of Backup Roll against Contact Fatigue Cracking

    Institute of Scientific and Technical Information of China (English)

    DOU Peng; LI You-guo; LIANG Kai-ming; BAI Bing-zhe

    2005-01-01

    In order to optimize the current grinding procedure of the backup roll of 2050 continuously variable crown (CVC) mills, the behavior of rolling contact fatigue (RCF) cracking was investigated. Two RCF short cracks, including vertical short crack and ratcheting short crack initiated from ratcheting, were observed. The behavior of both RCF cracks was analyzed in detail. Then a modified grinding procedure was proposed according to the behavior of RCF cracks and the preventive grinding strategy.

  14. Evaluation of minimum quantity lubrication grinding with nano-particles and recent related patents.

    Science.gov (United States)

    Li, Changhe; Wang, Sheng; Zhang, Qiang; Jia, Dongzhou

    2013-06-01

    In recent years, a large number of patents have been devoted to developing minimum quantity lubrication (MQL) grinding techniques that can significantly improve both environmentally conscious and energy saving and costeffective sustainable grinding fluid alternatives. Among them, one patent is about a supply system for the grinding fluid in nano-particle jet MQL, which produced MQL lubricant by adding solid nano-particles in degradable grinding fluid. The MQL supply device turns the lubricant to the pulse drops with fixed pressure, unchanged pulse frequency and the same drop diameter. The drops will be produced and injected in the grinding zone in the form of jet flow under high pressure gas and air seal. As people become increasingly demanding on our environment, minimum quantity lubrication has been widely used in the grinding and processing. Yet, it presents the defect of insufficient cooling performance, which confines its development. To improve the heat transfer efficiency of MQL, nano-particles of a certain mass fraction can be added in the minimum quantity of lubricant oil, which concomitantly will improve the lubrication effects in the processing. In this study, the grinding experiment corroborated the effect of nano-particles in surface grinding. In addition, compared with other forms of lubrication, the results presented that the grinding force, the friction coefficient and specific grinding energy of MQL grinding have been significantly weakened, while G ratio greatly rose. These are attributed to the friction oil-film with excellent anti-friction and anti-wear performance, which is generated nano-particles at the wheel/workpiece interface. In this research, the cooling performance of nano-particle jet MQL was analyzed. Based on tests and experiments, the surface temperature was assayed from different methods, including flood lubricating oil, dry grinding, MQL grinding and nano-particle jet MQL grinding. Because of the outstanding heat transfer

  15. ANALYSIS OF THE SURFACE PROFILE AND ITS MATERIAL SHARE DURING THE GRINDING INCONEL 718 ALLOY

    Directory of Open Access Journals (Sweden)

    Martin Novák

    2015-05-01

    Full Text Available Grinding is still an important method for surface finishing. At FPTM JEPU research, which deals with this issue is conducted. Experiments are carried out with grinding various materials under different conditions and then selected components of the surface integrity are evaluated. They include roughness Ra, Rm and Rz, Material ratio curve (Abbott Firestone curve and also the obtained roundness. This article deals with grinding nickel Inconel 718 alloy, when selected cutting grinding conditions were used and subsequently the surface profile and the material ratio curve were measured and evaluated.

  16. An experimental assessment on the performance of different lubrication techniques in grinding of Inconel 751

    Directory of Open Access Journals (Sweden)

    A.S.S. Balan

    2016-09-01

    Full Text Available The application of emulsion for combined heat extraction and lubrication requires continuous monitoring of the quality of emulsion to sustain a desired grinding environment; this is applicable to other grinding fluids as well. Thus to sustain a controlled grinding environment, it is necessary to adopt an effectively lubricated wheel-work interface. The current study was undertaken to assess experimentally the ​ effects of different grinding environments such as dry, minimum quantity lubrication (MQL and Cryo-MQL on performance, such as grinding force, temperature, surface roughness and chip morphology on Inconel 751, a higher heat resistance material posing thermal problems and wheel loading. The results show that grinding with the combination of both liquid nitrogen (LN2 and MQL lowers temperature, cutting forces, and surface roughness as compared with MQL and dry grinding. Specific cutting energy is widely used as an inverse measure of process efficiency in machining. It is found from the results that specific cutting energy of Cryo-MQL assisted grinding is 50–65% lower than conventional dry grinding. The grindability of Inconel 751 superalloy can be enhanced with Cryo-MQL condition.

  17. Effect of fiber orientations on surface grinding process of unidirectional C/SiC composites

    Science.gov (United States)

    Zhang, Lifeng; Ren, Chengzu; Ji, Chunhui; Wang, Zhiqiang; Chen, Guang

    2016-03-01

    The machining mechanism of woven ceramic matrix composites is one of the most challenging problems in composite application. To elucidate the grinding mechanism of the woven ceramic matrix composites, a new model material consisting of unidirectional CVI-C/SiC was prepared and ground. The composite was ground in three typical directions and the experimental investigation of the surface grinding process for this composite is described. In addition, the micro structural characteristics and grinding mechanism of the composite were analyzed. The result shows that brittle fracture is the dominant removal mechanism for grinding of the C/SiC composites, and the destroy form of the composites is mainly the syntheses of the matrix cracking, fiber fracture, and interfacial debonding. The grinding force follows the order: Normal > Longitudinal > Transverse, and the surface roughness follows: Longitudinal > Normal > Transverse. The grinding parameters (feed speed, cut depth, grinding speed) have great influence on the grinding force and surface roughness. Based on the findings, the grinding force and surface integrity of the woven ceramic matrix composites can be predicted. Furthermore, it is expected to provide a useful guideline for the design, evaluation and optimal application of the C/SiC composites.

  18. Nano finish grinding of brittle materials using electrolytic in-process dressing (ELID) technique

    Indian Academy of Sciences (India)

    M Rahman; A Senthil Kumar; H S Lim; K Fatima

    2003-10-01

    Recent developments in grinding have opened up new avenues for finishing of hard and brittle materials with nano-surface finish, high tolerance and accuracy. Grinding with superabrasive wheels is an excellent way to produce ultraprecision surface finish. However, superabrasive diamond grits need higher bonding strength while grinding, which metal-bonded grinding wheels can offer. Truing and dressing of the wheels are major problems and they tend to glaze because of wheel loading. When grinding with superabrasive wheels, wheel loading can be avoided by dressing periodically to obtain continuous grinding. Electrolytic inprocess dressing (ELID) is the most suitable process for dressing metal-bonded grinding wheels during the grinding process. Nano-surface finish can be achieved only when chip removal is done at the atomic level. Recent developments of ductile mode machining of hard and brittle materials show that plastically deformed chip removal minimizes the subsurface damage of the workpiece. When chip deformation takes place in the ductile regime, a defect-free nano-surface is possible and it completely eliminates the polishing process. ELID is one of the processes used for atomic level metal removal and nano-surface finish. However, no proper and detailed studies have been carried out to clarify the fundamental characteristics for making this process a robust one. Consequently, an attempt has been made in this study to understand the fundamental characteristics of ELID grinding and their influence on surface finish.

  19. Modeling and Simulation of Process-Machine Interaction in Grinding of Cemented Carbide Indexable Inserts

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2015-01-01

    Full Text Available Interaction of process and machine in grinding of hard and brittle materials such as cemented carbide may cause dynamic instability of the machining process resulting in machining errors and a decrease in productivity. Commonly, the process and machine tools were dealt with separately, which does not take into consideration the mutual interaction between the two subsystems and thus cannot represent the real cutting operations. This paper proposes a method of modeling and simulation to understand well the process-machine interaction in grinding process of cemented carbide indexable inserts. First, a virtual grinding wheel model is built by considering the random nature of abrasive grains and a kinematic-geometrical simulation is adopted to describe the grinding process. Then, a wheel-spindle model is simulated by means of the finite element method to represent the machine structure. The characteristic equation of the closed-loop dynamic grinding system is derived to provide a mathematic description of the process-machine interaction. Furthermore, a coupling simulation of grinding wheel-spindle deformations and grinding process force by combining both the process and machine model is developed to investigate the interaction between process and machine. This paper provides an integrated grinding model combining the machine and process models, which can be used to predict process-machine interactions in grinding process.

  20. Association between anticonvulsant drugs and teeth-grinding in children and adolescents with cerebral palsy.

    Science.gov (United States)

    Ortega, A O L; Dos Santos, M T B R; Mendes, F M; Ciamponi, A L

    2014-09-01

    The relation between teeth-grinding and the use of drugs acting on the central nervous system of cerebral palsy (CP) patients has not yet been described. The aim of this research was to evaluate the presence or absence of teeth-grinding (sleep and/or awake periods) in normal and in CP children and adolescents, as well as the association of teeth-grinding and use of anticonvulsant drugs. The sample consisted of 207 children and adolescents, divided into three groups: G1, individuals with CP who did not take anticonvulsant drugs; G2, individuals with CP administered medications on a regular basis; and CG, normal individuals. Logistic regression analyses were performed to evaluate the association of teeth-grinding with some variables. No significant statistical differences were observed regarding the presence or absence of teeth-grinding when G1 and G2 were compared. However, compared with the CG, a statistically significant difference was determined, with the CG showing fewer children presenting teeth-grinding (P drug therapy, the barbiturate group showed a greater frequency of teeth-grinding. CP children and adolescents show a greater and significant presence of grinding of the teeth compared with normal individuals. Subjects taking barbiturate drugs showed greater presence of teeth-grinding, than those who were taking medications from the other groups of anticonvulsant drugs. © 2014 John Wiley & Sons Ltd.

  1. Modeling and Experimental Investigation of Pressure Field in the Grinding Zone with Nanoparticle Jet of MQL

    Directory of Open Access Journals (Sweden)

    C. H. Li

    2013-01-01

    Full Text Available Solid nano particles were added in minimum quantity lubrication (MQL fluid medium to make nanofluids, that is, after the mixing and atomization of nanoparticle, lubricants and high pressure gas, to inject solid nano particle in the grinding zone with the form of jet flow. The mathematical model of two-phase flow pressure field of grinding zone with nanoparticle jet flow of MQL was established, and the simulation study was conducted. The results show that pressures in the grinding zone increased with the acceleration of grinding wheel, sharply decreased with the increased minimum clearance, and increased with the acceleration of jet flow. At three spraying angles of nozzles, when the nozzle angle was 15°, the pressure of grinding zone along the speed of grinding wheel was larger than the rest two angles. On the experimental platform built by KP-36 precision grinder and nanoparticle jet flow feed way, CY3018 pressure sensor was used to test the regularities of pressure field variations. The impact of the speed of grinding wheel, the gap between workpiece and grinding wheel, jet flow velocity, and spraying angles of nozzles on the pressure field of grinding zone was explored. The experimental result was generally consistent with the theoretical simulation, which verified the accuracy of the theoretical analysis.

  2. Grinding and polishing of conformal windows and domes

    Science.gov (United States)

    Fess, Edward; Ross, James; Matthews, Greg

    2017-05-01

    Conformal optics require special manufacturing techniques to produce them to optical tolerances. In many cases the materials used are very hard optical ceramics that present additional manufacturing challenges due to their hardness and grain structure. OptiPro has developed grinding technologies such as OptiSonic grinding, as well as sub-aperture polishing technologies like UltraForm Finishing (UFF) to manufacture these challenging components. We have also developed a custom computer aided manufacturing (CAM) software package, ProSurf, to generate the complex tool paths for both grinding and polishing processes. One of the main advantages of ProSurf over traditional CAM software packages is that it uses metrology feedback for deterministic corrections. The metrology input can be obtained from OptiPro's 5-axis UltraSurf metrology system, which is capable of measuring these complex shapes to sub-micron accuracies. Through the development of these technologies much work has been performed in creating, measuring and analyzing the alignment fiducials or datum's used to qualify the location of the optical surfaces. Understanding the sensitivity of the optical surface to any datum misalignment is critical to knowing not only where the part is in space, but how good the optical surfaces are to each other. Working with the optical designer to properly tolerance surfaces to these datums is crucial. This paper will present the technologies developed by OptiPro to manufacture conformal windows as well as information related to the optical surfaces sensitivity to datums and how accurately those datums can be measured.

  3. Application of cryogenic grinding to achieve homogenization of transuranic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, W.H.; Hill, D.D.; Lucero, M.E.; Jaramillo, L.; Martinez, H.E. [and others

    1996-08-01

    This paper describes work done at Los Alamos National Laboratory (LANL) in collaboration with the Department of Energy Rocky Flats Field Office (DOE/RFFO) and with the National Institute of Standards and Technology (NIST), Boulder, Colorado. Researchers on this project have developed a method for cryogenic grinding of mixed wastes to homogenize and, thereby, to acquire a representative sample of the materials. There are approximately 220,000 waste drums owned by the Rocky Flats Environmental Technology Site (RFETS)-50,000 at RFETS and 170,000 at the Idaho National Engineering Laboratory. The cost of sampling the heterogeneous distribution of waste in each drum is prohibitive. In an attempt to produce a homogeneous mixture of waste that would reduce greatly the cost of sampling, researchers at NIST and RFETS are developing a cryogenic grinder. The Los Alamos work herein described addresses the implementation issues of the task. The first issue was to ascertain whether samples of the {open_quotes}small particle{close_quotes} mixtures of materials present in the waste drums at RFETS were representative of actual drum contents. Second, it was necessary to determine at what temperature the grinding operation must be performed in order to minimize or to eliminate the release of volatile organic compounds present in the waste. Last, it was essential to evaluate any effect the liquid cryogen might have on the structural integrity and ventilation capacity of the glovebox system. Results of this study showed that representative samples could be and had been obtained, that some release of organics occurred below freezing because of sublimation, and that operation of the cryogenic grinding equipment inside the glovebox was feasible.

  4. Surface Topography of Fine-grained ZrO2 Ceramic by Two-dimensional Ultrasonic Vibration Grinding

    Institute of Scientific and Technical Information of China (English)

    DING Ailing; WU Yan; LIU Yongjiang

    2011-01-01

    The surface quality of fine-grained ZrO2 engineering ceramic were researched using 270# diamond wheel both with and without work-piece two-dimension ultrasonic vibration grinding(WTDUVG).By AFM images,the surface topography and the micro structure of the two-dimensional ultrasonic vibration grinding ceramics were especially analyzed.The experimental results indicate that the surface roughness is related to grinding vibration mode and the material removal mechanism.Surface quality of WTDUVG is superior to that of conventional grinding,and it is easy for two-dimensional ultrasonic vibration grinding that material removal mechanism is ductile mode grinding.

  5. Modulus Proposal for a Multi Axes Grinding of Sculptured Surfaces

    Science.gov (United States)

    Jandečka, Karel

    2009-11-01

    This paper presents the use of the CAD/CAM system Cimatron for free programming of NC grinding machines. NC technology use, first of all in milling, turning and drilling operations, is widely dispersed at present. Development of these technologies depends to some extent on the cutting tools which are to be produced and sharpened to a high quality. Usable properties of the cutting tools, e.g. the shape accuracy, the quality of function surfaces, etc., are inspired by the production technology used. This technology plays a main role in production and sharpening of powerful and complex shaped cutting tools.

  6. Corrosion of Cast Iron Mill Plates in Wet Grinding

    Directory of Open Access Journals (Sweden)

    Anthony ANDREWS

    2010-12-01

    Full Text Available Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or microstructures of the plates. Results are briefly discussed in terms of the contribution of corrosion to wear.

  7. Experimental and numerical investigations of hydroerosive grinding for injection components

    Energy Technology Data Exchange (ETDEWEB)

    Iben, Uwe; Weickert, Mathias [Robert Bosch GmbH, Stuttgart (Germany)

    2011-07-01

    Diesel injection injectors are very complicated hydraulic systems which contain among other things small throttles and small sized blow holes in order to inject the fuel precisely into the combustion chamber. Due to the extremely strong exhaust laws, the geometrical forms and tolerances of the hydraulic components have to be maintained. The hydroerosive grinding process (HE process) is used for manufacturing of small holes using in Diesel injection components. A mixture of oil and small sized particles are used to form the final geometrical shapes of the throttles and the blow holes. Simulation models help to understand the underlying physical process and to optimize the manufacturing parameters for an efficient production process. This paper presents an Euler-Euler approach for the numerical simulation of the HE process. It describes a two-phase slurry flow consisting of a liquid and a dispersed solid phase which causes wear at walls of devices. The continuous fluid phase is solved using a finite volume scheme in which the Large Eddy Simulation (LES) model is applied to resolve large-scale turbulent structures. The solid phase is disperse and treated as a second continuum in which drag and lift forces as well as added mass, pressure and history force are taken into account. Considering particle-particle interactions, the granular model from Gidaspow is used for particle volume concentrations over 1%. Investigations of erosion processes proofed that non-spherically shaped particles as well as harder particles increase the wear on devices significantly. Consequently, non-spherical particles are utilized for the hydroerosive grinding. Their steady drag, unsteady drag and lift coefficients, depending on the particle Reynolds number, are determined by a direct numerical simulation via an in-house LES Lattice-Boltzmann solver. This Lattice-Boltzmann method was presented for laminar flows by Hoelzer. In this work, interpolating functions of these coefficients are

  8. Application of electrolytic in-process dressing for high-efficiency grinding of ceramic parts. Research activities 1995--96

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, B.P. [Univ. of North Dakota, Grand Forks, ND (United States). Dept. of Mechanical Engineering

    1997-02-01

    The application of Electrolytic In-Process Dressing (ELID) for highly efficient and stable grinding of ceramic parts is discussed. This research was performed at the Institute of Physical and Chemical Research (RIKEN), Tokyo, Japan, June 1995 through August 1995. Experiments were conducted using a vertical machining center. The silicon nitride work material, of Japanese manufacture and supplied in the form of a rectangular block, was clamped to a vice which was firmly fixed on the base of a strain gage dynamometer. The dynamometer was clamped on the machining center table. Reciprocating grinding was performed with a flat-faced diamond grinding wheel. The output from the dynamometer was recorded with a data acquisition system and the normal component of the force was monitored. Experiments were carried out under various cutting conditions, different ELID conditions, and various grinding wheel bonds types. Rough grinding wheels of grit sizes {number_sign}170 and {number_sign}140 were used in the experiments. Compared to conventional grinding, there was a significant reduction in grinding force with ELID grinding. Therefore, ELID grinding can be recommended for high material removal rate grinding, low rigidity machines, and low rigidity workpieces. Compared to normal grinding, a reduction in grinding ratio was observed when ELID grinding was performed. A negative aspect of the process, this reduced G-ratio derives from bond erosion and can be improved somewhat by adjustments in the ELID current. The results of this investigation are discussed in detail in this report.

  9. Approximate creep feed grinding of austempared ductile cast iron; Osutenpa kyujo kokuen chutetsu no kin`i kuripu fido kensaku

    Energy Technology Data Exchange (ETDEWEB)

    Nakamitsu, K.; Shimizu, K. [Oita National College of Technology, Oita (Japan)

    1996-10-01

    Austempered ductile cast iron (ADI) was subjected to approximate creep feed grinding to measure and observe the grinding ratio, hardness of ground surface, grinding resistance, production of burrs, roughness of ground surface, and grinding burn to investigate the best abrasive grains and grinding conditions. The grinding ratio of SiC grains was far better than that of Al2O3 grains, being about 10 times or more. Surface hardness of ADI ground by SiC grains changed little, but that ground by Al2O3 grains increased. As regards grinding resistance, that of Al2O3 grains have less slope and tangential component forces, but that of SiC grains increased with the increase in the ground volume. While burrs produced in grinding with SiC grains are secondary burrs, those produced in grinding with Al2O3 grains are primary burrs. In comparison with the normal grinding, grinding burn was produced on the ground surface, complicate striped patterns and grinding burns were produced by chattering particularly in grinding with Al2O3 grains. 10 refs., 11 figs., 2 tabs.

  10. Slag founding: kinetic study and election of a grinding system

    Directory of Open Access Journals (Sweden)

    Salas Vinent, M. E.

    2001-06-01

    Full Text Available Here we offer results obtained in laboratories and industry, concerning the kinetic study of steelfounding in cement manufacture. We choose the most suitable grinding system, valuing also its economical and environmental repercussion. The obtained results indicated that the kinetic method is extremely useful to solve the practical problems in the conception and design of grinding systems, and it is also a speed and the inverted bolting-rell gap almost like a Arrhenius equation.

    Se presentan resultados logrados a escala de laboratorio e industrial referidos al estudio cinético de las escorias de fundición de aceros para la producción de cementos. Se realiza la elección del sistema de molienda más adecuado, valorando además el efecto económico y medio ambiental del mismo. De los resultados obtenidos se concluye que el método cinético resulta de extrema utilidad en la solución de problemas prácticos para la concepción y diseño de sistemas de molienda, amén de que en el plano teórico resulta una novedad la correlación encontrada entre la constante de velocidad de molienda y el inverso de la abertura del tamiz de modo similar a la ecuación de Arrhenius.

  11. Effects of grinding processes on enzymatic degradation of wheat straw.

    Science.gov (United States)

    Silva, Gabriela Ghizzi D; Couturier, Marie; Berrin, Jean-Guy; Buléon, Alain; Rouau, Xavier

    2012-01-01

    The effectiveness of wheat straw fine to ultra-fine grindings at pilot scale was studied. The produced powders were characterised by their particle-size distribution (laser diffraction), crystallinity (WAXS) and enzymatic degradability (Trichoderma reesei enzymatic cocktail). A large range of wheat-straw powders was produced: from coarse (median particle size ∼800 μm) to fine particles (∼50 μm) using sieve-based grindings, then ultra-fine particles ∼20 μm by jet milling and ∼10 μm by ball milling. The wheat straw degradability was enhanced by the decrease of particle size until a limit: ∼100 μm, up to 36% total carbohydrate and 40% glucose hydrolysis yields. Ball milling samples overcame this limit up to 46% total carbohydrate and 72% glucose yields as a consequence of cellulose crystallinity reduction (from 22% to 13%). Ball milling appeared to be an effective pretreatment with similar glucose yield and superior carbohydrate yield compared to steam explosion pretreatment.

  12. Analysis on Large Deformation Compensation Method for Grinding Machine

    Directory of Open Access Journals (Sweden)

    Wang Ya-jie

    2013-08-01

    Full Text Available The positioning accuracy of computer numerical control machines tools and manufacturing systems is affected by structural deformations, especially for large sized systems. Structural deformations of the machine body are difficult to model and to predict. Researchs for the direct measurement of the amount of deformation and its compensation are farly limited in domestic and overseas,not involved to calculate the amount of deformation compensation. A new method to compensate large deformation caused by self-weight was presented in the paper. First of all, the compensation method is summarized; Then,static force analysis was taken on the large grinding machine through APDL(ANSYS Parameter Design Language. It could automatic extract results and form data files, getting the N points displacement in the working stroke of mechanical arm. Then, the mathematical model and corresponding flat rectangular function were established. The conclusion that the new compensation method is feasible was obtained through the analysis of displacement of N points. Finally, the MATLAB as a tool is used to calculate compensate amount and the accuracy of the proposed method is proved. Practice shows that the error caused by large deformatiion compensation method can meet the requirements of grinding.  

  13. ARE THERE SIGNIFICANT DIFFERENCES BETWEEN DIRECT AND REVERSE GRINDING CIRCUITS?

    Directory of Open Access Journals (Sweden)

    Douglas Batista Mazzinghy

    2014-12-01

    Full Text Available The mining industry is famous for many paradigms regarding different flowsheet designs and the use of new technologies and equipment. In this context, a question often performed to process engineers is: what grinding circuit is more efficient, the direct or the reverse? A precise answer could only be given by experimental data and simulations. Simulations were performed using ModSimTM software considering parameters obtained by batch mill tests of an iron ore sample. The simulations, preliminarily, indicated no significant differences between the two circuit configurations for the sample tested. Subsequently, tests were conducted on a pilot scale with detailed measurement of all the variables necessary for a correct interpretation of the differences between the direct and reverse circuits. The test results confirmed the prediction obtained by simulation. This work provides the basis to test other ores and to understanding better the real differences between grinding circuit configurations. Thus, it is expected that some myths of the mineral industry, with respect to flowsheet choices, are overcome.

  14. Dry-grinded ultrafine cements hydration. physicochemical and microstructural characterization

    Directory of Open Access Journals (Sweden)

    Foteini Kontoleontos

    2013-04-01

    Full Text Available The aim of the present research work was the evaluation of the physicochemical and microstructural properties of two ultrafine cements, produced by dry grinding of a commercial CEM I 42.5N cement. The effect of grinding on particle size distribution was determined by laser scattering analyzer. All cements were tested for initial and final setting times, consistency of standard paste, soundness, flow of normal mortar and compressive strengths after 1, 2, 7 and 28 days. The effect of the fineness on the heat of hydration was also investigated. The hydration products were determined by X-ray diffraction analysis and by Fourier transform infrared spectroscopy, at 1, 2, 7 and 28 days. The microstructure of the hardened cement pastes and their morphological characteristics were examined by scanning electron microscopy. Porosity and pore size distribution were evaluated by mercury intrusion porosimetry. The effects of greater fineness on compressive strengths were evident principally at early ages. After the first 24 hours of hydration, the compressive strength of the finest cements was about 3 times higher (over 48 MPa than the corresponding of CEM I 42.5N (15.1 MPa.

  15. Effects of imbalance and geometric error on precision grinding machines

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.E.

    1997-06-01

    To study balancing in grinding, a simple mechanical system was examined. It was essential to study such a well-defined system, as opposed to a large, complex system such as a machining center. The use of a compact, well-defined system enabled easy quantification of the imbalance force input, its phase angle to any geometric decentering, and good understanding of the machine mode shapes. It is important to understand a simple system such as the one I examined given that imbalance is so intimately coupled to machine dynamics. It is possible to extend the results presented here to industrial machines, although that is not part of this work. In addition to the empirical testing, a simple mechanical system to look at how mode shapes, balance, and geometric error interplay to yield spindle error motion was modelled. The results of this model will be presented along with the results from a more global grinding model. The global model, presented at ASPE in November 1996, allows one to examine the effects of changing global machine parameters like stiffness and damping. This geometrically abstract, one-dimensional model will be presented to demonstrate the usefulness of an abstract approach for first-order understanding but it will not be the main focus of this thesis. 19 refs., 36 figs., 10 tables.

  16. An efficient, robust, and inexpensive grinding device for herbal samples like Cinchona bark

    DEFF Research Database (Denmark)

    Hansen, Steen Honoré; Holmfred, Else Skovgaard; Cornett, Claus;

    2015-01-01

    An effective, robust, and inexpensive grinding device for the grinding of herb samples like bark and roots was developed by rebuilding a commercially available coffee grinder. The grinder was constructed to be able to provide various particle sizes, to be easy to clean, and to have a minimum of d...

  17. Electrochemical aspects of grinding media-mineral interaction on sulphide flotation

    OpenAIRE

    Rao, Yelloji MK; Natarajan, KA

    1988-01-01

    Galvanic interaction between electrically conducting minerals may affect the mineral surface and influence their flotabilities. The metallographic examinations as well as hardness measurements have been made with grinding media. Rest potential, combination potential, galvanic current and polarization studies were made to understand the probable electrochemical interaction between grinding media and chalcopyrite. The galvanic contact lowered the flotability of chalcopyrite. AES and ESCA indica...

  18. Recognition of diamond grains on surface of fine diamond grinding wheel

    Institute of Scientific and Technical Information of China (English)

    Fengwei HUO; Zhuji JIN; Renke KANG; Dongming GUO; Chun YANG

    2008-01-01

    The accurate evaluation of grinding wheel sur-face topography, which is necessary for the investigation of the grinding principle, optimism, modeling, and simu-lation of a grinding process, significantly depends on the accurate recognition of abrasive grains from the measured wheel surface. A detailed analysis of the grain size distri-bution characteristics and grain profile wavelength of the fine diamond grinding wheel used for ultra-precision grinding is presented. The requirements of the spatial sampling interval and sampling area for instruments to measure the surface topography of a diamond grinding wheel are discussed. To recognize diamond grains, digital filtering is used to eliminate the high frequency disturb-ance from the measured 3D digital surface of the grinding wheel, the geometric features of diamond grains are then extracted from the filtered 3D digital surface, and a method based on the grain profile frequency characteris-tics, diamond grain curvature, and distance between two adjacent diamond grains is proposed. A 3D surface pro-filer based on scanning white light interferometry is used to measure the 3D surface topography of a #3000 mesh resin bonded diamond grinding wheel, and the diamond grains are then recognized from the 3D digital surface. The experimental result shows that the proposed method is reasonable and effective.

  19. Capturing action of cooling lubricants in grinding and evaluation of its effectiveness

    Science.gov (United States)

    Tyukhta, A. V.; Khandozhko, A. V.; Vasilenko, Yu V.

    2016-04-01

    Methods of coolant supply are considered to be aiming at capturing and neutralization of the flare of grinding waste and noxious coolant fumes during flat grinding with a wheel periphery. Study and evaluation of the new coolant functional property - capturing - are presented.

  20. THERMAL AND PHYSICAL FEATURES OF MAGNETIC AND ELECTRIC GRINDING PROCESS OF GAS AND THERMAL PROTECTIVE COATINGS

    Directory of Open Access Journals (Sweden)

    N. V. Spiridonov

    2008-01-01

    Full Text Available The paper reveals thermal zones of magnetic and electric grinding process. The influence of electric and physical parameters of magnetic and electric grinding on temperature in the zone of gas and thermal protective coatings has been established in the paper.

  1. Investigation of the formation process of two piracetam cocrystals during grinding

    DEFF Research Database (Denmark)

    Rehder, Sönke; Klukkert, Marten; Löbmann, Korbinian;

    2011-01-01

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam......-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than...... for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form...

  2. Measurement of Force Components and Ra Surface Roughness Parameter During Grinding Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Grdulska A.

    2014-10-01

    Full Text Available The paper deals with the measurements of selected parameters during grinding process of aerospace industry alloy. Grinding is one of the most important methods of shaping machine elements. As a result of grinding with high dimensional and shape accuracy as well as with the expected parameters describing the state of the surface layer (SL should be obtained. Grinding difficult to machine materials used in the aerospace industry is an issue currently being examined by various research centres. An excellent example is the analysis of the grinding process of titanium alloys, as these materials have very poor machinability due to the tendency to adherence to abrasive materials, low thermal conductivity, high strength and compliance at elevated temperatures, which may adversely impact on the quality of SL. A number of factors influence on shaping SL. Worth mentioning are mechanical and thermal phenomena, as well as the type of cutting fluid and abrasive materials

  3. Investigation of the formation process of two piracetam cocrystals during grinding

    DEFF Research Database (Denmark)

    Rehder, Sönke; Klukkert, Marten; Löbmann, Korbinian

    2011-01-01

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam......-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than...... for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form...

  4. Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding

    Directory of Open Access Journals (Sweden)

    Keith Gordon

    2011-10-01

    Full Text Available Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form of the piracetam and no polymorphic cocrystals were obtained.

  5. Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding

    Science.gov (United States)

    Rehder, Sönke; Klukkert, Marten; Löbmann, Korbinian A. M.; Strachan, Clare J.; Sakmann, Albrecht; Gordon, Keith; Rades, Thomas; Leopold, Claudia S.

    2011-01-01

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e., piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form of the piracetam and no polymorphic cocrystals were obtained. PMID:24309304

  6. 20CrMnMo钢渗碳齿轮磨削裂纹成因分析%Causes Analysis on Grinding Cracks of 20CrMnMo Steel Carburized Gears

    Institute of Scientific and Technical Information of China (English)

    孙胜伟; 宋亚虎; 刘铁山; 史向阳; 赵学谦

    2016-01-01

    采用化学成分分析、金相分析、显微硬度测试以及残余应力测定等方法对某 2 0 CrMnMo钢渗碳齿轮磨削裂纹产生原因进行了分析.结果表明:该齿轮产生磨削裂纹主要是由于磨削过程中表面产生严重的二次淬火烧伤和回火烧伤,二次淬火烧伤的次表面及边缘回火烧伤区硬度大幅下降及表面受拉应力,两者共同作用下产生了磨削裂纹;另外,渗碳层中存在针状马氏体和大量残余奥氏体,增加了齿轮磨削开裂的敏感性,这是齿轮产生磨削裂纹的另一个重要原因.%The forming reasons for grinding cracks of 20CrMnMo steel carburized gears were analyzed by means of chemical composition analysis,metallographic examination,microhardness test and residual stress test. The results show that the main reasons for the grinding cracks were secondary quenching burn and tempering burn on the gear surface during grinding.Grinding cracks were caused by the combined effects of serious decline in hardness and surface tensile stress at the subsurface of the secondary quenching burn area and the edge tempering burn area.Besides,the grinding cracking sensitivity was increased due to the acicular martensite and massive retained austenite existing in the carburized layer,which was also an important reason for the grinding cracks.

  7. Optimization of the dressing parameters in cylindrical grinding based on a generalized utility function

    Science.gov (United States)

    Aleksandrova, Irina

    2016-01-01

    The existing studies, concerning the dressing process, focus on the major influence of the dressing conditions on the grinding response variables. However, the choice of the dressing conditions is often made, based on the experience of the qualified staff or using data from reference books. The optimal dressing parameters, which are only valid for the particular methods and dressing and grinding conditions, are also used. The paper presents a methodology for optimization of the dressing parameters in cylindrical grinding. The generalized utility function has been chosen as an optimization parameter. It is a complex indicator determining the economic, dynamic and manufacturing characteristics of the grinding process. The developed methodology is implemented for the dressing of aluminium oxide grinding wheels by using experimental diamond roller dressers with different grit sizes made of medium- and high-strength synthetic diamonds type ??32 and ??80. To solve the optimization problem, a model of the generalized utility function is created which reflects the complex impact of dressing parameters. The model is built based on the results from the conducted complex study and modeling of the grinding wheel lifetime, cutting ability, production rate and cutting forces during grinding. They are closely related to the dressing conditions (dressing speed ratio, radial in-feed of the diamond roller dresser and dress-out time), the diamond roller dresser grit size/grinding wheel grit size ratio, the type of synthetic diamonds and the direction of dressing. Some dressing parameters are determined for which the generalized utility function has a maximum and which guarantee an optimum combination of the following: the lifetime and cutting ability of the abrasive wheels, the tangential cutting force magnitude and the production rate of the grinding process. The results obtained prove the possibility of control and optimization of grinding by selecting particular dressing

  8. Innovative grinding wheel design for cost-effective machining of advanced ceramics. Phase I, final report

    Energy Technology Data Exchange (ETDEWEB)

    Licht, R.H.; Ramanath, S.; Simpson, M.; Lilley, E.

    1996-02-01

    Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics. This program was a cooperative effort involving three Norton groups representing a superabrasive grinding wheel manufacturer, a diamond film manufacturing division and a ceramic research center. The program was divided into two technical tasks, Task 1, Analysis of Required Grinding Wheel Characteristics, and Task 2, Design and Prototype Development. In Task 1 we performed a parallel path approach with Superabrasive metal-bond development and the higher technical risk, CVD diamond wheel development. For the Superabrasive approach, Task 1 included bond wear and strength tests to engineer bond-wear characteristics. This task culminated in a small-wheel screening test plunge grinding sialon disks. In Task 2, an improved Superabrasive metal-bond specification for low-cost machining of ceramics in external cylindrical grinding mode was identified. The experimental wheel successfully ground three types of advanced ceramics without the need for wheel dressing. The spindle power consumed by this wheel during test grinding of NC-520 sialon is as much as to 30% lower compared to a standard resin bonded wheel with 100 diamond concentration. The wheel wear with this improved metal bond was an order of magnitude lower than the resin-bonded wheel, which would significantly reduce ceramic grinding costs through fewer wheel changes for retruing and replacements. Evaluation of ceramic specimens from both Tasks 1 and 2 tests for all three ceramic materials did not show evidence of unusual grinding damage. The novel CVD-diamond-wheel approach was incorporated in this program as part of Task 1. The important factors affecting the grinding performance of diamond wheels made by CVD coating preforms were determined.

  9. Comparison of tungsten carbide and stainless steel ball bearings for grinding single maize kernels in a reciprocating grinder

    Science.gov (United States)

    Reciprocating grinders can grind single maize kernels by shaking the kernel in a vial with a ball bearing. This process results in a grind quality that is not satisfactory for many experiments. Tungesten carbide ball bearings are nearly twice as dense as steel, so we compared their grinding performa...

  10. Pyrolysis of a waste from the grinding of scrap tyres.

    Science.gov (United States)

    Fernández, A M; Barriocanal, C; Alvarez, R

    2012-02-15

    The fibres that are used to reinforce tyres can be recovered as a waste in the process of grinding of scrap tyres. In this paper beneficiation through pyrolysis is studied since the fibres are made up of polymers with a small amount of rubber because the latter is difficult to separate. The experiments were performed at three temperatures (400, 550 and 900°C) in a horizontal oven. The three products - gas, oil and char - obtained from the pyrolysis were investigated. The composition of the gas was analyzed by means of gas chromatography. The oil was studied by gas chromatography and infrared spectroscopy. The char porous structure was determined by N(2) adsorption. In addition, the topography of the chars was studied by means of scanning electron microscopy (SEM). The products resulting from the pyrolysis of the fibres were compared with those obtained from scrap rubber.

  11. Nano surface generation of grinding process using carbon nano tubes

    Indian Academy of Sciences (India)

    S Prabhu; B K Vinayagam

    2010-12-01

    Nano surface finish has become an important parameter in the semiconductor, optical, electrical and mechanical industries. The materials used in these industries are classified as difficult to machine materials such as ceramics, glasses and silicon wafers. Machining of these materials up to nano accuracy is a great challenge in the manufacturing industry. Finishing of micro components such as micro-moulds, micro-lenses and micro-holes need different processing techniques. Conventional finishing methods used so far become almost impossible or cumbersome. In this paper, a nano material especially multi wall carbon nano tube is used in the machining process like grinding to improve the surface characteristics from micro to nano level.

  12. Function of grinding fly ash in production of aluminum foam

    Institute of Scientific and Technical Information of China (English)

    WANG Yong; YAO Guang-chun; LI Bing

    2006-01-01

    The fly ash was added to melt to increase the melt viscosity. The main components are quartz and mullite in the fly ash,therefore it's a kind of hardness ceramic particles. After grinding for 10 h, the spherical particles increase and new surface is produced which will improve their performance. The cell wall was observed by SEM, many fly ash particles are in the wall. These particles tend to increase the molten aluminum surface viscosity, postpone the exhaust course, sustain the liquid within the film and delay the onset of rupture. Finally, the aluminum foam with uniform cell structure can be obtained. The density is about 0.4 g/cm3,porosity is in the range of 85%-90% and the aperture is 4-7 mm.

  13. Residuation theory

    CERN Document Server

    Blyth, T S; Sneddon, I N; Stark, M

    1972-01-01

    Residuation Theory aims to contribute to literature in the field of ordered algebraic structures, especially on the subject of residual mappings. The book is divided into three chapters. Chapter 1 focuses on ordered sets; directed sets; semilattices; lattices; and complete lattices. Chapter 2 tackles Baer rings; Baer semigroups; Foulis semigroups; residual mappings; the notion of involution; and Boolean algebras. Chapter 3 covers residuated groupoids and semigroups; group homomorphic and isotone homomorphic Boolean images of ordered semigroups; Dubreil-Jacotin and Brouwer semigroups; and loli

  14. Intra-pulp temperature increase of equine cheek teeth during treatment with motorized grinding systems: influence of grinding head position and rotational speed

    Science.gov (United States)

    2014-01-01

    Background In equine practice, teeth corrections by means of motorized grinding systems are standard procedure. The heat resulting from that treatment may cause irreparable damage to the dental pulp. It has been shown that a 5.5°C temperature rise may cause severe destruction in pulp cells. Hence, the capability to continuously form secondary dentine is lost, and may lead, due to equine-typical occlusal tooth abrasion, to an opening of the pulp cavity. To obtain reliable data on the intra-pulp increase in temperature during corrective treatments, equine cheek teeth (CT) were modified in a way (occlusal surface smoothed, apical parts detached, pulp horns standardized) that had been qualified in own former published studies. All parameters influencing the grinding process were standardized (force applied, initial temperatures, dimensions of pulp horns, positioning of grinding disk, rotational speed). During grinding experiments, imitating real dental treatments, the time span for an intra-pulp temperature increase of 5.5°C was determined. Results The minimum time recorded for an intra-pulp temperature increase of 5.5°C was 38 s in mandibular CT (buccal grinding, 12,000 rpm) and 70 s in maxillary CT (flat occlusal grinding, 12,000 rpm). The data obtained showed that doubling the rotational speed of the disk results in halving the time span after which the critical intra-pulp temperature increase in maxillary CT is reached. For mandibular CT, the time span even drops by two thirds. Conclusion The use of standardized hypsodont CT enabled comparative studies of intra-pulp heating during the grinding of occlusal tooth surfaces using different tools and techniques. The anatomical structure of the natural vital hypsodont tooth must be kept in mind, so that the findings of this study do not create a deceptive sense of security with regard to the time-dependent heating of the native pulp. PMID:24559121

  15. Controlled wear of vitrified abrasive materials for precision grinding applications

    Indian Academy of Sciences (India)

    M J Jackson; B Mills; M P Hitchiner

    2003-10-01

    The study of bonding hard materials such as aluminium oxide and cubic boron nitride (BN) and the nature of interfacial cohesion between these materials and glass is very important from the perspective of high precision grinding. Vitrified grinding wheels are typically used to remove large volumes of metal and to produce components with very high tolerances. It is expected that the same grinding wheel is used for both rough and finish machining operations. Therefore, the grinding wheel, and in particular its bonding system, is expected to react differently to a variety of machining operations. In order to maintain the integrity of the grinding wheel, the bonding system that is used to hold abrasive grains in place reacts differently to forces that are placed on individual bonding bridges. This paper examines the role of vitrification heat treatment on the development of strength between abrasive grains and bonding bridges, and the nature of fracture and wear in vitrified grinding wheels that are used for precision grinding applications.

  16. Reseach on Mill-grinding Experiment of Grinding Wheel with Phyllotactic Pattern%磨粒族叶序排布砂轮的铣磨实验研究

    Institute of Scientific and Technical Information of China (English)

    王军; 赵良兵; 赵成义; 吕玉山

    2013-01-01

    In order to realize the ordering of the grinding wheel abrasive surface assignment, this paper combined with phyllotaxis theory and grinding mechanism, and manufactured phyllotactic pattern grinding wheel by UV lithography method and electroplating technology. The mill-grinding experiment results show that; the grinding performance of phyllotactic pattern grinding wheel is superior to what of disordered arrangement grinding wheel.%为了实现砂轮表面磨料排布的有序化,本文将仿生学叶序理论与磨削机理相结合,利用光刻技术和复合电镀技术制备出了磨粒族叶序排布砂轮.铣磨实验结果表明:磨粒族叶序排布砂轮的磨削性能优于普通无序排布砂轮.

  17. Grinding efficiency of abutment tooth with both dentin and core composite resin on axial plane.

    Science.gov (United States)

    Miho, Otoaki; Sato, Toru; Matsukubo, Takashi

    2015-01-01

    The purpose of this study was to evaluate grinding efficiency in abutment teeth comprising both dentin and core composite resin in the axial plane. Grinding was performed over 5 runs at two loads (0.5 or 0.25 N) and two feed rates (1 or 2 mm/sec). The grinding surface was observed with a 3-D laser microscope. Tomographic images of the grinding surfaces captured perpendicular to the feed direction were also analyzed. Using a non-ground surface as a reference, areas comprising only dentin, both dentin and core composite resin, or only core composite resin were analyzed to determine the angle of the grinding surface. Composite resins were subjected to the Vickers hardness test and scanning electron microscopy. Data were statistically analyzed using a one-way analysis of variance and multiple comparison tests. Multiple regression analysis was performed for load, feed rate, and Vickers hardness of the build-up material depending on number of runs. When grinding was performed at a constant load and feed rate, a greater grinding angle was observed in areas comprising both dentin and composite resin or only composite resin than in areas consisting of dentin alone. A correlation was found between machinability and load or feed rate in areas comprising both dentin and composite resin or composite resin alone, with a particularly high correlation being observed between machinability and load. These results suggest that great caution should be exercised in a clinical setting when the boundary between the dentin and composite resin is to be ground, as the angle of the grinding surface changes when the rotating diamond point begins grinding the composite resin.

  18. Optimization of Metal Removal Rateon Cylindrical Grinding For Is 319 Brass Using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Gaurav Upadhyay

    2015-06-01

    Full Text Available Cylindrical grinding is one of the most important metal cutting processes used extensively in the Metal finishing operations. Metal removal rate and surface finish are the important output responses in the production with respect to quantity and quality respectively. The objective of this paper is to arrive at the optimal grinding conditions that will maximize metal removal rate when grinding IS 319 brass. Empirical models were developed using design of experiments by Taguchi L9 Orthogonal Array and the adequacy of the developed model is tested with ANOVA.

  19. [Radical formation by grinding of commercial tablets according to hospital and pharmacy prescription].

    Science.gov (United States)

    Kuzuya, Masayuki; Kondo, Shin-ichi; Ishikawa, Takaaki; Furuta, Youji; Aramaki, Hideki; Sasai, Yasushi; Yamauchi, Yukinori

    2005-04-01

    We examined mechanoradical formation in the grinding process of commercial tablets using electron spin resonance (ESR). Mechanoradicals were detected in all tested samples (23 types of commercial tablets) when the ball-milling of tablets was conducted under anaerobic conditions and some were fairly stable even in air. Thus the grinding may cause changes in the physicochemical properties of ingredients included in commercial tablets. Because high quality is demanded in pharmaceuticals, these results suggest more caution should be taken in the grinding of commercial tablets in hospitals and pharmacies.

  20. Affecting mechanism of grinding aid during ultrafine grinding%超细粉碎过程助磨剂的作用机理

    Institute of Scientific and Technical Information of China (English)

    杨华明; 邱冠周

    2000-01-01

    通过粉体ζ-电位、矿浆粘度测定及光电子能谱(XPS)和分散率分析,研究了搅拌磨超细粉碎滑石粉过程中助磨剂的助磨行为.分析了六偏磷酸钠与滑石粉的表面作用及吸附特性,提出了助磨剂在超细粉碎过程中的吸附模型.此外,探讨了助磨剂对超细粉碎行为的影响.研究结果表明,助磨剂通过与滑石粉的吸附作用,降低了矿浆粘度,从而提高了超细粉碎的效率.%The aiding behavior of hexametaphosphate(hexa) during uhrafine grinding of talc with stirred mill is studiedthrough analysis of ζ-potenfial,pulp viscosity,XPS and scattering rate in the paper. The surfacial effect and adsorptioncharacteristics of Hexa on talc particles are analysed. A typical model of grinding aid during ultrafine grinding is given.Effect of Hexa on ultrafine grinding behavior is also discussed. The results show that it is the adsorption of Hexa and re-ducing pulp viscosity that improve the grinding efficiency.

  1. Influence of grinding on service properties of VT-22 powder applied in additive technologies

    Science.gov (United States)

    Zakharov, M. N.; Rybalko, O. F.; Romanova, O. V.; Gelchinskiy, B. R.; Il’inykh, S. A.; Krashaninin, V. A.

    2017-01-01

    Powder of titanium alloy (VT-22) produced by plasma-spraying was subjected to grinding to obtain powder with size less 100 microns. These powders were sprayed by plasma unit using two types of gases, namely, air and air with methane (spraying in water and sputtering of coating on steel support). Influence of grinding time on yield of powder of required fraction was studied. Morphology and phase composition of the grinded powder and plasma sprayed one were under investigation. In the result of experiments, it appears that the grinding time genuinely influences the chemical and phase compositions, but there is no effect on physical-processing properties. For powders after plasma spraying some changes of non-metal elements content were detected by chemical analysis. Using gaseous mixture of air and methane in plasma spraying unit leads to formation of a new phase in the powder according X-ray diffraction data.

  2. Force-controlled analysis tool for optimization of precision CNC grinding processes

    Science.gov (United States)

    Vogt, C.; Fähnle, O.; Rascher, R.

    2017-06-01

    While setting up grinding processes for optics fabrication, the optimum tool and process parameters have to be chosen. Unfortunately, datasheets of commercial grinding tools contain only information about grit type and size, bond material, tool shape etc., leaving out any information about process parameters to be applied or tool lifetime or performance. For this reason, tools and machining parameters are commonly adjusted during iterative experimental test runs using actual workpieces from production batches which is time consuming, expensive and without guarantee that the optimum set of machining parameters are achieved. In this paper we present a method to determine grinding tools process window for a given workpiece material. That way, ideal machining parameters can be determined offline for maximum reliability and productivity. In addition, the gained data provides the basis to identify the most suitable grinding tool for the desired application.

  3. IN SITU TRUING/DRESSING OF DIAMOND WHEEL FOR PRECISION GRINDING

    Institute of Scientific and Technical Information of China (English)

    WAN Daping; WANG Yan; HU Dejin

    2008-01-01

    An application for achieving on-machine truing/dressing and monitoring of diamond wheel is dealt with in dry grinding. A dry electrical discharge (ED) assisted truing and dressing method is adopted in preparation of diamond grinding wheels. Effective and precise truing/dressing of a diamond wheel is carried out on a CNC curve grinding machine by utilizing an ED assisted diamond dresser. The dressed wheel is monitored online by a CCD vision system. It detects the topography changes of a wheel surface. The wear condition is evaluated by analyzing the edge deviation of a wheel image. The benefits of the proposed methods are confirmed by the grinding experiments. The designed truing/dressing device has high material removal rate, low dresser wear, and hence guarantees a desired wheel surface. Real-time monitoring of the wheel profile facilitates determining the optimum dressing amount, dressing interval, and the compensation error.

  4. Modeling and Simulation of Process-Machine Interaction in Grinding of Cemented Carbide Indexable Inserts

    National Research Council Canada - National Science Library

    Feng, Wei; Yao, Bin; Chen, BinQiang; Zhang, DongSheng; Zhang, XiangLei; Shen, ZhiHuang

    2015-01-01

      Interaction of process and machine in grinding of hard and brittle materials such as cemented carbide may cause dynamic instability of the machining process resulting in machining errors and a decrease in productivity...

  5. Modeling and analysis of grinding force in ultrasonic honing considering the scale effect

    Directory of Open Access Journals (Sweden)

    Linzheng Ye

    2016-01-01

    Full Text Available To research the power ultrasonic honing mechanism at the micro scale, the scale effect is considered and the strain gradient plasticity theory based on the dislocation mechanism (MSG is applied to establish the model of a whetstone grinding force, and the simulation analysis is conducted. Results show: the grinding force will increase when the scale effect is considered; the main influence parameter is honing depth on the grinding force; the grinding force increases nonlinearly with the continued reduce of honing depth after which decreases to 1.4 μm, which decreases slightly with the increase of the relative velocity of a whetstone. So the material becomes difficult to remove at the micro scale.

  6. Optimization of Cylindrical Grinding Process Parameters on C40E Steel Using Taguchi Technique

    Directory of Open Access Journals (Sweden)

    Naresh Kumar

    2015-01-01

    Full Text Available Surface finish and dimensional accuracy play a vital role in the today’s engineering industry. There are several methods used to achieve good surface finish like burnishing, honing and lapping, and grinding. Grinding is one of these ways that improves the surface finish and dimensional accuracy simultaneously. C40E steel has good industrial application in manufacturing of shafts, axles, spindles, studs, etc. In the present work the cylindrical grinding of C40E steel is done for the optimization of grinding process parameters. During this experimental work input process parameters i.e. speed, feed, depth of cut is optimized using Taguchi L9 orthogonal array. Analysis of variance (ANOVA concluded that surface roughness is minimum at the 210 rpm, 0.11mm/rev feed, and 0.04mm depth of penetration.

  7. Quality Estimation of Dry Grinding of Skiving Cutters With Organic Bonding Diamond Wheels

    Science.gov (United States)

    Filippov, A. V.; Shamarin, N. N.; Podgornykh, O. A.; Rubtsov, V. E.

    2016-08-01

    Engineering process preparation requires proper preparation of cutting tools. It influences not only the performance of the tools but also the quality of workpiece surface machining. One of the promising environmentally friendly trends of mechanical treatment is grinding without using lubricating cooling liquid. This method can considerably influence the quality of cutting tools grinding. Smoothing skiving turning is an effective treatment method providing high efficiency and workpiece quality. Proper preparation of cutting edges is especially important in this process. For that purpose we have carried out a research in grinding changeable carbide inserts for skiving turning by means of grinding wheels with different grain size. The influence of different combinations of wheels on roughness of the inserts front and rear surfaces and quality of cutting edge was studied with the help of laser confocal microscopy.

  8. Effects of supercritical water and mechanochemical grinding treatments on physicochemical properties of chitin.

    Science.gov (United States)

    Osada, Mitsumasa; Miura, Chika; Nakagawa, Yuko S; Kaihara, Mikio; Nikaido, Mitsuru; Totani, Kazuhide

    2013-02-15

    This study examined the effects of a combined pretreatment with supercritical water and mechanochemical grinding with a ball mill on the physicochemical properties of chitin and its enzymatic degradation. Following pretreatment with a combination of supercritical water and grinding, chitin had a lower mean molecular weight, a lower crystallinity index, a lower crystallite size, greater d-spacing, weaker hydrogen bonds, and the amide group was more exposed compared with untreated chitin. These properties increased the hydrophilicity of the chitin and enhanced its enzymatic degradation. The N,N'-diacetylchitobiose (GlcNAc)(2) yield after enzymatic degradation of chitin following pretreatment with supercritical water (400 °C, 1 min) and grinding (800 rpm, 10 min) was 93%, compared with 5% without any treatment, 37% with supercritical water pretreatment alone (400 °C, 1 min), and 60% with grinding alone (800 rpm, 30 min).

  9. Dynamic modeling and analysis of the closed-circuit grinding-classification process

    Institute of Scientific and Technical Information of China (English)

    Yunfei Chu; Wenli Xu; Weihan Wan

    2005-01-01

    Mathematical models of the grinding process are the basis of analysis, simulation and control. Most existent models including theoretical models and identification models are, however, inconvenient for direct analysis. In addition, many models pay much attention to the local details in the closed-circuit grinding process while overlooking the systematic behavior of the process as a whole. From the systematic perspective, the dynamic behavior of the whole closed-circuit grinding-classification process is considered and a first-order transfer function model describing the dynamic relation between the raw material and the product is established.The model proves that the time constant of the closed-circuit process is lager than that of the open-circuit process and reveals how physical parameters affect the process dynamic behavior. These are very helpful to understand, design and control the closed-circuit grinding-classification process.

  10. The effects of three different grinding methods in DNA extraction of ...

    African Journals Online (AJOL)

    uwerhiavwe

    2013-04-17

    Apr 17, 2013 ... downstream PCR analysis without liquid nitrogen, the cowpea DNA was extracted by ... obtained by three grinding methods both in CTAB method and SDS method. Without ..... the proteins and lipids that form the membranes.

  11. Effect of cryogenic grinding on volatile and fatty oil constituents of cumin (Cuminum cyminum L.) genotypes.

    Science.gov (United States)

    Sharma, L K; Agarwal, D; Rathore, S S; Malhotra, S K; Saxena, S N

    2016-06-01

    Effect of cryogenic grinding on recovery of volatile oil, fatty oil percentage and their constituents in two cumin (Cuminum cyminum L.) genotypes have been analyzed. Cryogenic grinding not only retains the volatiles but enhanced the recovery by 33.9 % in GC 4 and 43.5 % in RZ 209. A significant increase (29.9 %) over normal grinding in oil percentage was also observed in genotype RZ 209. This increase was, however, less (15.4 %) in genotype GC 4. Nineteen major compounds were identified in the essential oil of both genotypes. The two grinding techniques had significant effects on dependent variables, viz., volatile oil and monoterpenes. Cuminaldehyde was the main constituent in both genotypes, content of which increased from 48.2 to 56.1 % in GC 4 on cryo grinding. Content of terpines were found to decrease in cryo ground samples of GC 4 and either decrease or no change was found in RZ 209. Organoleptic test showed more pleasant aroma in cryo ground seeds of both the genotypes. Significant increase was also reported in fatty oil yield due to cryogenic grinding. Fatty acid methyl ester (FAME) analysis showed oleic acid as major FAME content of which increased from 88.1 to 94.9 % in RZ 209 and from 88.2 to 90.1 % in GC 4 on cryogenic grinding. Other prominent FAME were palmitic, palmitoleic and stearic acid. Results indicated commercial potential of cryogenic grinding technology for cumin in general and spices in particular for better retention of flavour and quality in spices.

  12. Experimental Investigation on the Performance of Grinding Assisted Electrochemical Discharge Drilling of Glass

    OpenAIRE

    Ladeesh V. G.; Manu R

    2016-01-01

    Grinding assisted electrochemical discharge drilling (G-ECDD) is a novel technique for producing micro and macro holes in brittle materials including advanced ceramics and glass, both efficiently and economically. G-ECDD involves the use of a rotating diamond core drill as the tool in a normal electrochemical discharge machine setup. The material removal happens by a combination of thermal melting due to electric discharges, followed by grinding action of diamond grits and chemical etching ac...

  13. Surface roughness of zirconia for full-contour crowns after clinically simulated grinding and polishing

    Institute of Scientific and Technical Information of China (English)

    Rim Hmaidouch; Wolf-Dieter Mu ller; Hans-Christoph Lauer; Paul Weigl

    2014-01-01

    The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups (n515). Fifteen specimens (group 1) were glazed and 15 specimens (group 2) were veneered with feldspathic ceramic and then glazed. Prior to grinding, maximum roughness depth (Rmax) values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 mm, 10 mm, and 7.5 mm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmax values were determined. Differences between groups were examined using one-way analysis of variance (ANOVA). The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing. It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing;more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.

  14. Mechanical Property of Low Chromium Semi-Steel Grinding Ball Prepared by Cross Rolling

    Institute of Scientific and Technical Information of China (English)

    CHANG Li-min; MENG De-liang; NIE Pu-lin; LIU Jian-hua

    2004-01-01

    The preparing method, rolling technology and mechanical properties of low chromium semi-steel grinding ball by cross rolling were studied. The results show that when the low chromium semi-steel bar is forged from 55 mm to 50 mm, cross-rolled into grinding ball at 1 000-1 050 ℃, air cooled and tempered at 550 ℃ for 2 h, the best mechanical properties, especially the abrasive resistance under the action of hard abrasive, can be obtained.

  15. Surface roughness of zirconia for full-contour crowns after clinically simulated grinding and polishing.

    Science.gov (United States)

    Hmaidouch, Rim; Müller, Wolf-Dieter; Lauer, Hans-Christoph; Weigl, Paul

    2014-12-01

    The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups (n=15). Fifteen specimens (group 1) were glazed and 15 specimens (group 2) were veneered with feldspathic ceramic and then glazed. Prior to grinding, maximum roughness depth (Rmax) values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 µm, 10 µm, and 7.5 µm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmax values were determined. Differences between groups were examined using one-way analysis of variance (ANOVA). The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing. It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing; more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.

  16. Next generation grinding spindle for cost-effective manufacture of advanced ceramic components

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, J.A.; Laurich, M.A.

    2000-01-01

    Finish grinding of advanced structural ceramics has generally been considered an extremely slow and costly process. Recently, however, results from the High-Speed, Low-Damage (HSLD) program have clearly demonstrated that numerous finish-process performance benefits can be realized by grinding silicon nitride at high wheel speeds. A new, single-step, roughing-process capable of producing high-quality silicon nitride parts at high material removal rates while dramatically reducing finishing costs has been developed.

  17. Accurate Tooth Lead Crowning without Twist in Cylindrical Helical Gear Grinding

    OpenAIRE

    Zhang, Hu; Fang, Chenggang; Huang, XiaoDiao

    2014-01-01

    Form grinding is a popular finishing process in manufacturing cylindrical gears with tooth flank modification. The tooth flanks are usually twisted when a lead crowning is performed only through additional radial motion during double flank grinding. For solving the problem, this paper proposes a method for application of tooth lead crowning without twist in cylindrical helical gears based on the idea of tooth form correction for spiral bevel and hypoid gears. In this method, the motion of eac...

  18. Role of classification in grinding using the electromagnetic mill. A case study

    Directory of Open Access Journals (Sweden)

    Wolosiewicz-Glab Marta

    2016-01-01

    Full Text Available In the process of classification, one of the methods used to evaluate the effectiveness classifiers is to plot a separation curve, which determines the size of seprated particles and characterizes the process accuracy. The article presents an assessment of the impact of parameters on grinding and classification using an electromagnetic mill. The results allow a detailed assessment of the effectiveness and efficiency of the device and facilitate the optimization of the grinding process by establishing an appropriate control algorithms.

  19. 3MK1420外沟磨床砂轮修整器改造%Improvement of grinding wheel dresser for 3MK1420 outer groove grinding machine

    Institute of Scientific and Technical Information of China (English)

    姚淑敏

    2013-01-01

    Aiming at the problem of chain drive in grinding wheel dresser for 3MK1420 outer groove grinding machine, chain drive is superseded by steel belt drive so as to improve the drive stability and the dressing quality.%  针对3MK1420外沟磨床砂轮修整器链条传动存在的问题,采用钢带传动取代链条传动,提高了传动平稳性及砂轮修整质量。

  20. Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

    Science.gov (United States)

    Guerra, Ruben; Taydakov, Ilya; Tonucci, Lucia; d’Alessandro, Nicola; Lamaty, Frederic; Martinez, Jean

    2017-01-01

    Summary The mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins was investigated in the presence of various poly(ethylene) glycols (PEGs), as safe grinding assisting agents (liquid-assisted grinding, LAG). A comparative study under dry-grinding conditions was also performed. The results showed that the cyclization reaction was influenced by the amount of the PEG grinding agents. In general, cleaner reaction profiles were observed in the presence of PEGs, compared to dry-grinding procedures.

  1. The effects of pf grind quality on coal burnout in a 1 MW combustion test facility

    Energy Technology Data Exchange (ETDEWEB)

    Richelieu Barranco; Michael Colechin; Michael Cloke; Will Gibb; Edward Lester [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering, Nottingham Fuel and Energy Centre

    2006-05-15

    A study was carried out to determine the effect of pf particle size distribution on coal burnout propensity in a 1 MW pulverised fuel burner. The specific aim of the work was to assess the improvement in combustion performance achievable by retrofitting commercially available high performance static or dynamic classifiers to existing plants. Two coals were used and were selected as representative of extremes in fuel characteristics experienced by coal importing utilities in Europe. Each coal was fired in the unit at a range of grind sizes to determine the overall impact of a variable performance from a mill. The levels of unburnt carbon in the resultant flyashes for the two coals showed significantly different behaviour. For the higher volatile coal, the unburnt carbon was found to be insensitive to grind quality. However, the coarser grinds of the other coal produced significantly lower unburnt carbon than expected when compared with the finest grinds. Generally the results indicate that the installation of improved classification technology, leading to a finer product, will help to lower unburnt carbon levels. Nevertheless, further work will be necessary to establish the levels of diminishing returns for grind size, burnout performance and grind costs. 21 refs., 4 figs., 4 tabs.

  2. Diagnostic value of clinical grind test for carpometacarpal osteoarthritis of the thumb.

    Science.gov (United States)

    Merritt, Melissa M; Roddey, Toni S; Costello, Charles; Olson, Sharon

    2010-01-01

    Clinical Measurement. Thumb carpometacarpal (CMC) osteoarthritis is a frequent cause of thumb pain. To evaluate the interrater reliability and the criterion validity of the grind test for thumb CMC osteoarthritis. Radiological evaluation was used as the gold standard. Seventy thumbs of 54 persons with various hand disorders were included in the study. The grind test was performed by two physical therapists, and radiographs were evaluated by a certified hand surgeon, all blinded to the participants' diagnosis and other test results. Interrater reliability was compared with a kappa statistic, and the sensitivity, specificity, likelihood ratios, and predictive values were calculated from a 232 table. A kappa value of 0.48 was calculated as the interrater reliability. The sensitivity of the grind test was 42% and 53%, depending on tester. The specificity of the grind test was 80% and 93%, depending on tester. The positive likelihood ratio was 2.65 and 6.00, and the negative likelihood ratio was 0.59 and 0.62. The positive predictive value was 91% and 96%, depending on tester. The negative predictive value was 68% and 70%, depending on tester. The grind test has moderate reliability and accurately confirms the diagnosis of CMC osteoarthritis and identifies those who do not have CMC osteoarthritis. However, a negative grind test does not necessarily reflect negative radiographic evidence of thumb CMC osteoarthritis. n/a. Copyright © 2010 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

  3. Analysis and Compensation for Gear Accuracy with Setting Error in Form Grinding

    Directory of Open Access Journals (Sweden)

    Chenggang Fang

    2015-01-01

    Full Text Available In the process of form grinding, gear setting error was the main factor that influenced the form grinding accuracy; we proposed an effective method to improve form grinding accuracy that corrected the error by controlling the machine operations. Based on establishing the geometry model of form grinding and representing the gear setting errors as homogeneous coordinate, tooth mathematic model was obtained and simplified under the gear setting error. Then, according to the gear standard of ISO1328-1: 1997 and the ANSI/AGMA 2015-1-A01: 2002, the relationship was investigated by changing the gear setting errors with respect to tooth profile deviation, helix deviation, and cumulative pitch deviation, respectively, under the condition of gear eccentricity error, gear inclination error, and gear resultant error. An error compensation method was proposed based on solving sensitivity coefficient matrix of setting error in a five-axis CNC form grinding machine; simulation and experimental results demonstrated that the method can effectively correct the gear setting error, as well as further improving the forming grinding accuracy.

  4. Grinding performance evaluation of porous composite-bonded CBN wheels for Inconel 718

    Directory of Open Access Journals (Sweden)

    Chen Zhenzhen

    2014-08-01

    Full Text Available For high-efficiency grinding of difficult-to-cut materials such as titanium and nickel alloys, a high porosity is expected and also a sufficient mechanical strength to satisfy the function. However, the porosity increase is a disadvantage to the mechanical strength. As a promising pore forming agent, alumina bubbles are firstly induced into the abrasive layer to fabricate porous cubic boron nitride (CBN wheels. When the wheel porosity reaches 45%, the bending strength is still high up to 50 MPa with modified orderly pore distribution. A porous CBN wheel was fabricated with a total porosity around 30%. The grinding performance of the porous composite-bonded CBN wheel was evaluated in terms of specific force, specific grinding energy, and grinding temperature, which were better than those of the vitrified one under the same grinding conditions. Compared to the vitrified CBN wheel, clear straight cutting grooves and less chip adhesion are observed on the ground surface and there is also no extensive loading on the wheel surface after grinding.

  5. Some Key Technologies of a New-type CNC Curve Grinding Machine

    Institute of Scientific and Technical Information of China (English)

    WU Qi; HU De-jin

    2007-01-01

    This paper presented a new-type CNC curve grinding machine, in order to conquer the disadvantages of conventional NC curve grinding machine and improve surface quality, dimensional accuracy and machining efficiency. The new-type grinder adopts some high and new technologies:①the normal tracing device could make grinding wheel coincide with the normal direction of the machining points in work piece, and improve surface quality and dimensional accuracy;②the digital image on-line recognition system could monitor machining process and compensate wheel wear in real time;③linear motor drive mechanism could realize the exact adjustment of the grinding head digitally and increase the machining efficiency. The math models of normal tracing and circular tolerance zone were presented. The experimental results show that the new-type CNC curve grinding machine equipped with the three devices mentioned above is easy to realize the precision grinding of any complex curve, and improve surface quality, dimensional accuracy and machining efficiency.

  6. Research on Ultrasonic Vibration Grinding of the Hard and Brittle Materials

    Institute of Scientific and Technical Information of China (English)

    YANG Xin-hong; HAN Jie-cai; ZHANG Yu-min; ZUO Hong-bo; ZHANG Xue-jun

    2006-01-01

    It is well known that grinding techniques are main methods to machine hard and brittle materials such as engineering ceramics. But the conventional grinding has many shortcomings such as poorer surface finish, quicker wear and tear of grinding tools, lower efficiency and so on. Ultrasonic vibration grinding (UVG) which combines ultrasonic machining and grinding emerged as a developing and promising technique in recent years. In this paper, experimental studies on UVG were conducted on several kinds of hard and brittle material by altering processing parameters such as vibration frequency and its amplitude, diamond abrasive grit size, cutting depth, feeding speed and rotary speed of tools. The experimental results show that alteration in any of above mentioned parameters will bring effects on the processed surface finish of these materials. Of them, the diamond abrasive grit size has the greatest. Moreover, conventional grinding experiments were also carried out on these materials. By comparison, it was found that the UVG is superior to the conventional method in terms of the ground surface quality, the working efficiency and the wear rate of tools.

  7. Beneficiation of low grade graphite ore of eastern India by two-stage grinding and flotation

    Directory of Open Access Journals (Sweden)

    Vasumathi N.

    2014-01-01

    Full Text Available A low grade graphite run-of-mine (r.o.m ore from eastern India was studied for its amenability to beneficiation by flotation technique. The petrography studies indicate that the ore primarily consists of quartz and graphite with minor quantity of mica. It analyzed 89.89% ash and 8.59% fixed carbon. The ore was crushed in stages followed by primary coarse wet grinding to 212 μm (d80. Rougher flotation was carried out in Denver flotation cell to eliminate gangue as much as possible in the form of primary tailings with minimal loss of carbon. Diesel & pine oil were used as collector and frother respectively. Regrinding of rougher concentrate to150 μm (d80 was resorted to further liberate the graphite values and was followed by multi-stage cleaning. This two-stage grinding approach involving a primary coarse grinding and regrinding of rougher float followed by its multi-stage cleaning was found to yield required grade of concentrate for applications such as refractories, batteries and high temperature lubricants. This approach is supposed to retain the flake size of coarse, free and liberated graphite, if available, during primary coarse grinding and rougher flotation stage with minimal grinding energy costs as against the usual practice of single stage grinding in the case of many ores. A final concentrate of 8.97% weight recovery with 5.80% ash and 92.13% fixed carbon could be achieved.

  8. High speed low damage grinding of advanced ceramics - Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, J.A.; Malkin, S.

    2000-02-01

    In the manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. As a result, one of the most challenging tasks faced by manufacturing process engineers is the development of a ceramic finishing process to maximize part throughput while minimizing costs and associated scrap levels. The efforts summarized in this report represent the second phase of a program whose overall objective was to develop a single-step, roughing-finishing process suitable for producing high-quality silicon nitride parts at high material removal rates and at substantially lower cost than traditional, multi-stage grinding processes. More specifically, this report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding which employs elevated wheel speeds to achieve the small grain depths of cut necessary for low-damage grinding while operating at relatively high material removal rates. The study employed the combined use of laboratory grinding tests, mathematical grinding models, and characterization of the resultant surface condition. A single-step, roughing-finishing process operating at high removal rates was developed and demonstrated.

  9. Virtual Sensors for On-line Wheel Wear and Part Roughness Measurement in the Grinding Process

    Directory of Open Access Journals (Sweden)

    Ander Arriandiaga

    2014-05-01

    Full Text Available Grinding is an advanced machining process for the manufacturing of valuable complex and accurate parts for high added value sectors such as aerospace, wind generation, etc. Due to the extremely severe conditions inside grinding machines, critical process variables such as part surface finish or grinding wheel wear cannot be easily and cheaply measured on-line. In this paper a virtual sensor for on-line monitoring of those variables is presented. The sensor is based on the modelling ability of Artificial Neural Networks (ANNs for stochastic and non-linear processes such as grinding; the selected architecture is the Layer-Recurrent neural network. The sensor makes use of the relation between the variables to be measured and power consumption in the wheel spindle, which can be easily measured. A sensor calibration methodology is presented, and the levels of error that can be expected are discussed. Validation of the new sensor is carried out by comparing the sensor’s results with actual measurements carried out in an industrial grinding machine. Results show excellent estimation performance for both wheel wear and surface roughness. In the case of wheel wear, the absolute error is within the range of microns (average value 32 μm. In the case of surface finish, the absolute error is well below Ra 1 μm (average value 0.32 μm. The present approach can be easily generalized to other grinding operations.

  10. Multiobjective Optimization of ELID Grinding Process Using Grey Relational Analysis Coupled with Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    S. Prabhu

    2014-06-01

    Full Text Available Carbon nanotube (CNT mixed grinding wheel has been used in the electrolytic in-process dressing (ELID grinding process to analyze the surface characteristics of AISI D2 Tool steel material. CNT grinding wheel is having an excellent thermal conductivity and good mechanical property which is used to improve the surface finish of the work piece. The multiobjective optimization of grey relational analysis coupled with principal component analysis has been used to optimize the process parameters of ELID grinding process. Based on the Taguchi design of experiments, an L9 orthogonal array table was chosen for the experiments. The confirmation experiment verifies the proposed that grey-based Taguchi method has the ability to find out the optimal process parameters with multiple quality characteristics of surface roughness and metal removal rate. Analysis of variance (ANOVA has been used to verify and validate the model. Empirical model for the prediction of output parameters has been developed using regression analysis and the results were compared for with and without using CNT grinding wheel in ELID grinding process.

  11. Grinding performance evaluation of porous composite-bonded CBN wheels for Inconel 718

    Institute of Scientific and Technical Information of China (English)

    Chen Zhenzhen; Xu Jiuhua; Ding Wenfeng; Ma Changyu

    2014-01-01

    For high-efficiency grinding of difficult-to-cut materials such as titanium and nickel alloys, a high porosity is expected and also a sufficient mechanical strength to satisfy the function. However, the porosity increase is a disadvantage to the mechanical strength. As a promising pore forming agent, alumina bubbles are firstly induced into the abrasive layer to fabricate porous cubic boron nitride (CBN) wheels. When the wheel porosity reaches 45%, the bending strength is still high up to 50 MPa with modified orderly pore distribution. A porous CBN wheel was fabricated with a total porosity around 30%. The grinding performance of the porous composite-bonded CBN wheel was evaluated in terms of specific force, specific grinding energy, and grinding temper-ature, which were better than those of the vitrified one under the same grinding conditions. Com-pared to the vitrified CBN wheel, clear straight cutting grooves and less chip adhesion are observed on the ground surface and there is also no extensive loading on the wheel surface after grinding.

  12. Dechlorination of pentachlorophenol by grinding at low rotation speed in short time

    Institute of Scientific and Technical Information of China (English)

    Zhi Xu; Xiaoyu Zhang; Qingzhi Fei

    2015-01-01

    In order to apply grinding method for degradation of pentachlorophenol (PCP) to an industrial scale, the propor-tion of different materials [CaO, SiO2 and CO(NH2)2] and the size of grinding balls were examined. For saving en-ergy and increasing dechlorination efficiency, the rotation speed and grinding time were maintained at relatively low values. At a mass ratio of grinding bal s to materials (40:1), PCP was added into a big steel jar (300 ml) with other materials to grind at 300 r·min−1 for 5 h. The results indicated that when PCP was mixed with CaO and SiO2 in a molar ratio of 1:60:60, the best dechlorination of 58.4%was achieved. CO(NH2)2 could not be used as hydro-gen donor in the dehalogenation by mechanochemical reaction, since it restrained the dechlorination process. The size of grinding balls has significant effect on the reaction. The experiment with 5 mm steel balls indicates that the weight is too light to provide appropriate energy for the reaction, while steel balls of 10 and 15 mm could give better dechlorination reaction. It indicates that dechlorination depends on the mass of balls and fill rate.

  13. Clenching and grinding: effect on masseter and sternocleidomastoid electromyographic activity in healthy subjects.

    Science.gov (United States)

    Venegas, Macarena; Valdivia, José; Fresno, María Javiera; Miralles, Rodolfo; Gutiérrez, Mario Felipe; Valenzuela, Saúl; Fuentes, Aler

    2009-07-01

    This study compares the effect of clenching and grinding on masseter and sternocleidomastoid electromyographic (EMG) activity during different jaw posture tasks in the sagittal plane. The study included 34 healthy subjects with natural dentition, Class I bilateral molar Angle relationship, and absence of posterior occlusal contacts during mandibular protrusion. An inclusion criterion was that subjects had to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the right masseter and sternocleidomastoid muscles. EMG activity was recorded while the subjects were in standing position, during the following jaw posture tasks: A. maximal clenching in the intercuspal position; B. grinding from intercuspal position to edge-to-edge protrusive contact position; C. maximal clenching in the edge-to-edge protrusive contact position; D. grinding from edge-to-edge protrusive contact position to intercuspal position; E. grinding from retrusive contact position to intercuspal position. EMG activities in tasks B, C, D, and E were significantly lower than in task A in both muscles (mixed model with unstructured covariance matrix). EMG activity among tasks B, C, D, and E did not show significant differences in both muscles, except between tasks D and E in the masseter muscle. A higher effect was observed on the masseter than on the sternocleidomastoid muscle to avoid excessive muscular activity during clenching and grinding. The EMG patterns observed could be of clinical importance in the presence of parafunctional habits, i.e., clenching and/or grinding.

  14. Design and experimental research of the on-line detection system for diamond arc grinding wheel

    Science.gov (United States)

    Zhang, Feihu; Li, Chen; Liu, Zhongde; Ren, Lele; Xie, Haisheng

    2016-10-01

    The principle of measuring displacement by eddy current sensor was derived. The calibration experiment was carried out for 5 kinds of different materials, which showed that the linearity of eddy current sensor was better, and the sensitivity of eddy current sensor varied with different materials. Based on the principle of measuring displacement by eddy current sensor, the on-line detection system for diamond circular wheel was designed, and the data acquisition was realized by using LABVIEW software. By moving the eddy current sensor in the vertical direction with the grinding wheel fixed, the coordinate of arc in the grinding wheel was obtained. The radius of the grinding wheel was fitted by using the genetic algorithm, which showed that the fitting results were accurate. The data acquisition of the grinding wheel was carried out in a cycle by fixing the electric eddy current sensor and the circulars of the grinding wheel in different processes, namely before dressing, after dressing and after shaping. The results showed that the circular of the grinding wheel after dressing and after shaping were significantly improved compared with that before dressing.

  15. Pyrolysis of a waste from the grinding of scrap tyres

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.M. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain); Barriocanal, C., E-mail: carmenbr@incar.csic.es [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain); Alvarez, R. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer The pyrolysis of reinforcing fibres obtained from scrap tyres has been studied. Black-Right-Pointing-Pointer The results have been compared to scrap tyre granules. Black-Right-Pointing-Pointer A higher temperature is needed for the total decomposition of the fibres. Black-Right-Pointing-Pointer More compounds with heteroatoms (O, N) were found in the oil from the fibres. Black-Right-Pointing-Pointer Chars from the fibres exhibit lower BET surface and mesopore volume. - Abstract: The fibres that are used to reinforce tyres can be recovered as a waste in the process of grinding of scrap tyres. In this paper beneficiation through pyrolysis is studied since the fibres are made up of polymers with a small amount of rubber because the latter is difficult to separate. The experiments were performed at three temperatures (400, 550 and 900 Degree-Sign C) in a horizontal oven. The three products - gas, oil and char - obtained from the pyrolysis were investigated. The composition of the gas was analyzed by means of gas chromatography. The oil was studied by gas chromatography and infrared spectroscopy. The char porous structure was determined by N{sub 2} adsorption. In addition, the topography of the chars was studied by means of scanning electron microscopy (SEM). The products resulting from the pyrolysis of the fibres were compared with those obtained from scrap rubber.

  16. Numerical Simulation of a Grinding Process Model for the Spatial Work-pieces: Development of Modeling Techniques

    Directory of Open Access Journals (Sweden)

    S. A. Voronov

    2015-01-01

    Full Text Available The article presents a literature review in simulation of grinding processes. It takes into consideration the statistical, energy based, and imitation approaches to simulation of grinding forces. Main stages of interaction between abrasive grains and machined surface are shown. The article describes main approaches to the geometry modeling of forming new surfaces when grinding. The review of approaches to the chip and pile up effect numerical modeling is shown. Advantages and disadvantages of grain-to-surface interaction by means of finite element method and molecular dynamics method are considered. The article points out that it is necessary to take into consideration the system dynamics and its effect on the finished surface. Structure of the complex imitation model of grinding process dynamics for flexible work-pieces with spatial surface geometry is proposed from the literature review. The proposed model of spatial grinding includes the model of work-piece dynamics, model of grinding wheel dynamics, phenomenological model of grinding forces based on 3D geometry modeling algorithm. Model gives the following results for spatial grinding process: vibration of machining part and grinding wheel, machined surface geometry, static deflection of the surface and grinding forces under various cutting conditions.

  17. X-ray residual stress analysis on machined and tempered HPSN-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Immelmann, S.; Welle, E.; Reimers, W. [Hahn-Meitner-Institut Berlin GmbH (Germany)

    1997-11-15

    The residual stress state induced by grinding and tempering of hot pressed silicon nitride (HPSN) samples is studied by X-ray diffraction. The results reveal that the residual stress values at the surface of the samples as well as their gradient within the penetration depth of the X-rays depend on the sintering aid and thus, on the glassy phase content of the HPSN. Tempering of the ground HPSN reduces the residual stress values due to microplastic deformation, whereas an oxidation of the glassy phase leads to the formation of compressive residual stresses. (orig.) 35 refs.

  18. Analysing a Relationship Between Wheel Wear and Cutting Forces During Diamond Grinding

    Directory of Open Access Journals (Sweden)

    M. A. Shavva

    2014-01-01

    Full Text Available In diamond grinding cutting forces affect the quality of the machined surface. We can estimate a wear rate of the diamond wheel by the magnitude of the forces and promptly resort to the restoration of its cutting properties. To solve this problem it is necessary to define a relationship between grinding wheel wear and cutting forces. There was no this dependence found in the sources of literature.The forces acting on a single worn diamond grain are considered to find the relationship between wheel wear and cutting forces. The main forces acting on the diamond grain are such as a reaction force of machining material, a frictional force over a worn place of the grain, and a total pressure on the contact surface of the grain and machining material. According to calculation results, in grinding the cutting forces are proportional to the hardness of machining material, and depend on the grain wear, as well as on the process operation conditions.The paper presents a technique for calculating the number of cutting (active grains per unit surface of diamond wheel to determine a total cutting force in grinding. The number of cutting grains depends on the properties of diamond wheel and on the operation conditions of grinding process.During grinding a total cutting force is calculated through the single grain cutting force, the number of cutting grains per unit surface of the grinding wheel and the contact area between the wheel and the work piece. Theoretical calculation of the forces is based on the condition that protrusions of all cutting grains are identical and all grains have a maximum wear, i.e. maximum worn place of grain.Calculations based on proposed theoretical formulas are compared with the calculations from the empirical formulas given in the literature. Varying the operation conditions of grinding makes the comparison. Convergence of results in the range of 5-20% is regarded as acceptable.On the BMSTU base flat diamond grinding of tungsten

  19. Grinding behavior and surface appearance of (TiCp+TiBw)/Ti-6Al-4V titanium matrix composites

    Institute of Scientific and Technical Information of China (English)

    Ding Wenfeng; Zhao Biao; Xu Jiuhua; Yang Changyong; Fu Yucan; Su Honghua

    2014-01-01

    (TiCp+TiBw)/Ti-6Al-4V titanium matrix composites (PTMCs) have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were dis-cussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally ben-eficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.

  20. Research Progress of Interfacial Chemism of High Efficiency Organic Grinding Fluid for Si3N4 Ceramics

    Institute of Scientific and Technical Information of China (English)

    TIAN Xin-li; YANG Jun-fei; WU Zhi-yuan; HU Zhong-xiang

    2005-01-01

    Grinding is a most important machining method for Si3N4 ceramics. Utilizing interracial chemistry reac tion membrane between grinding fluid and Si3N4 ceramics can reduce friction factor, soften surface layer and meanwhile improve the grinding efficiency, which is a bran-new research direction. This article, based on high efficiency grinding of Si3N4 ceramics by the way of half plasticity removal, descanted on the assistant function of interface chemistry reaction to improve the removal rate of Si3N4 ceramics in the application of organic grinding fluids represented by alcohols grinding fluid. To target action mechanism research, it applies the methods of classification,comparison and induction, and advanced test equipments to explore the effects of long, short carbochain alcohol and their water solutions acting as grinding fluids. In addition, it also discusses the effective function of three groups of organic matters such as perhalogeno hydrocarbon, cationic surfactant and tetra ethoxysilane acting as grinding fluid components from different angles, reveals their mechanisms of action, and supplies theoretical basis for the development of machining ceramic grinding fluid of high efficiency, low cost.

  1. Surface quality prediction model of nano-composite ceramics in ultrasonic vibration-assisted ELID mirror grinding

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Bo; Chen, Fan; Jia, Xiao-feng; Zhao, Chong-yang; Wang, Xiao-bo [Henan Polytechnic University, Jiaozuo (China)

    2017-04-15

    Ultrasonic vibration-assisted Electrolytic in-process dressing (ELID) grinding is a highly efficient and highly precise machining method. The surface quality prediction model in ultrasonic vibration-assisted ELID mirror grinding was studied. First, the interaction between grits and workpiece surface was analyzed according to kinematic mechanics, and the surface roughness model was developed. The variations in surface roughness under different parameters was subsequently calculated and analyzed by MATLAB. Results indicate that compared with the ordinary ELID grinding, ultrasonic vibration-assisted ELID grinding is superior, because it has more stable and better surface quality and has an improved range of ductile machining.

  2. Knowledge acquirement in grinding process%磨削过程知识学习

    Institute of Scientific and Technical Information of China (English)

    吕长飞; 李郝林

    2012-01-01

    Buffing time and takt time in grinding process incarnated the grinding process parameters directly.Roughingprocess is the key of grinding and the rising part of acoustic emission signal curve in roughing process contains most abundant information.The fuzzy rule based on the triangular partition evenly was adapted for knowledge acquisition and learning process from the rising roughing part of grinding acoustic e-mission signal to establish corresponding relation between buffing time ,takt time and gradient of rising roughing part of grinding acoustic emission signal curve.Thus the gradient of rising roughing part of grinding acoustic emission signal curve corresponding to any buffing time and takt time is obtainetiln this way the rationality in selecting machining parameters could be estimated in order to select automatically and control intelligently the machining parameters in grinding process.Therefore the machining quality is ensured as well as on-line adjustment for machining parameters and intelligentized grinding in grinding process are realized.%磨削加工光磨时间、加工节拍直接体现磨削加工参数,粗磨过程的好坏是磨削过程的关键,磨削过程声发射信号粗磨段上升部分包含着磨削过程最丰富的信息,采用平均三角分配模糊规则对磨削过程声发射信号粗磨段上升部分进行知识获取和自学习,建立磨削加工光磨时间、加工节拍与磨削声发射曲线粗磨段上升部分斜率之间的对应关系,据此可得到任意光磨时间、加工节拍时对应的磨削声发射曲线粗磨段上升部分斜率.以此判断加工参数选择的合理性,以实现磨削加工的加工参数自动选择和智能控制,确保加工质量,实现磨削过程加工参数在线调整、磨削智能化.

  3. 钢丝磨削试验研究%Steel Wire Grinding Test

    Institute of Scientific and Technical Information of China (English)

    李家春; 张萍

    2012-01-01

    砂带磨削作为一种新工艺,在机械加工领域发挥着越来越大的作用,满足了各种加工要求。本文简单介绍了砂带磨削的概念,阐述了一个针对钢丝表面除锈的新型砂带磨削设备的工作原理及其机床的主要机构,并通过试验研究磨削压力、金属去除率、砂带磨损、磨削比、磨削深度、钢丝走速之间的关系,为砂带修磨线材生产线提供了合理的磨削工艺参数。%As a new process, the abrasive belt grinding plays an increasingly important role in the field of machi- ning, which meets a variety of processing requirements. This paper introduces the concept of abrasive belt grinding briefly, describes the work principle of a new belt grinder to remove rust from the steel wire surface and the main structure of the device. Tests were conducted to study the relationships between grinding force, metal removal rate, belt wear rate, grinding ratio, grinding depth and wire walking speed, which provides rational parameters for wire snagging line with abrasive belt.

  4. Fundamental studies on enhancing heat transfer in contact zone during high efficiency grinding

    Institute of Scientific and Technical Information of China (English)

    XU; Hongjun(徐鸿钧); FU; Yucan(傅玉灿); XU; Xipeng(徐西鹏); XU; Xipeng

    2002-01-01

    On the basis of research on the thermal effect in grinding contact zone during high effi-ciency grinding, an idea of enhancing heat transfer in contact zone using high pressure water jetimpinging is advanced. Fundamental heat transfer experiments on enhancing heat transfer withhigh pressure water jet impinging were completed. The maximum speed of jet impinging reaches110m/s. The experimental results of transient and steady-state experiment prove that the criticalheat flux and the heat-transfer coefficient of water jet impinging are 70 and 30 times those of thepool boiling, respectively. Furthermore, a new grinding fluid supply system was employed to en-hance heat transfer in grinding zone by high-pressure water jet impingement during creep feedgrinding. The experimental results show that high-pressure water jet impinging has remarkablecooling effect. The temperature of the workpiece surface can be steadily kept below 100℃, whilethe workpiece is badly burnt with conventional coolant supply. The study will exploit an importantresearch orientation that has great potentialities in the high efficiency grinding. Further perfectionof this study will not only enable us to increase the available material removal rate to a new levelbut also solve the workpiece burn problem of the difficult-to-machining materials in high efficiencygrinding,

  5. 硬质合金刀具螺旋槽缓进给磨削力研究%Research on Grinding Forces of Creep Feed Grinding Cemented Carbide Tool Helical Grooves

    Institute of Scientific and Technical Information of China (English)

    宋铁军; 周志雄; 李伟; 任莹晖

    2014-01-01

    The grinding forces of creep feed grinding cemented carbide tool helical groove were an-alyzed by grinding wheel discretization method that the grinding wheel was regarded as composion of different elementary discs.Based on the grinding forces and torques of creep feed grinding cemented carbide tool helical groove,a mathematical model of grinding force ratio was established to describe the blunting of the diamond grains.The accurate signals of the grinding forces and torques were achieved by setting up a measurement system.The grinding force ratio was analyzed based on the mathematical model and the experimental data.The results show that the grinding force ratio can be used for grinding process evaluation.%用离散化方法将砂轮看作是由一组不同直径的单位厚度薄片组成的,分析了硬质合金刀具螺旋槽缓进给成形磨削的磨削力;基于工件轴向磨削力和力矩建立了一个表征砂轮锐利程度的磨削力比数学模型。通过建立的测力系统测量了螺旋槽缓进给磨削过程中轴向磨削力和力矩,并对其信号进行了分析。在理论和实验的基础上获得了两种磨削参数下的磨削力比。研究结果表明,磨削力比可作为硬质合金刀具螺旋槽缓进给磨削过程的评价参数。

  6. Occlusal splints for treating sleep bruxism (tooth grinding).

    Science.gov (United States)

    Macedo, C R; Silva, A B; Machado, M A; Saconato, H; Prado, G F

    2007-10-17

    Sleep bruxism is an oral activity characterised by teeth grinding or clenching during sleep. Several treatments for sleep bruxism have been proposed such as pharmacological, psychological, and dental. To evaluate the effectiveness of occlusal splints for the treatment of sleep bruxism with alternative interventions, placebo or no treatment. We searched the Cochrane Oral Health Group's Trials Register (to May 2007); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 1); MEDLINE (1966 to May 2007); EMBASE (1980 to May 2007); LILACS (1982 to May 2007); Biblioteca Brasileira de Odontologia (1982 to May 2007); Dissertation, Theses and Abstracts (1981 to May 2007); and handsearched abstracts of particular importance to this review. Additional reports were identified from the reference lists of retrieved reports and from article reviews about treating sleep bruxism. There were no language restrictions. We selected randomised or quasi-randomised controlled trials (RCTs), in which splint therapy was compared concurrently to no treatment, other occlusal appliances, or any other intervention in participants with sleep bruxism. Data extraction was carried out independently and in duplicate. Validity assessment of the included trials was carried out at the same time as data extraction. Discrepancies were discussed and a third review author consulted. The author of the primary study was contacted when necessary. Thirty-two potentially relevant RCTs were identified. Twenty-four trials were excluded. Five RCTs were included. Occlusal splint was compared to: palatal splint, mandibular advancement device, transcutaneous electric nerve stimulation, and no treatment. There was just one common outcome (arousal index) which was combined in a meta-analysis. No statistically significant differences between the occlusal splint and control groups were found in the meta-analyses. There is not sufficient evidence to state that the occlusal splint is

  7. Ultra-fine grinding of silicate materials under the use of new resin bond diamond tools

    Science.gov (United States)

    Henkel, Sebastian; Bliedtner, Jens; Rädlein, Edda; Schulze, Christian; Rost, Matthias; Gerhardt, Martin; Fuhr, Michael

    2017-06-01

    The fabrication of high-quality optical components involves great effort. Polishing often functions as the final step in a manufacturing chain. To reduce the conventionally time-consuming, complex polishing process with loose grain, an interesting approach with novel resin bond grinding tools is presented for surface smoothing. Various processing-experiments were carried out, regarding different silicate materials such as BK7® and fused silica. Among other results it is shown, that good surface qualities with low roughness down to Ra = 8 nm or Rq = 10 nm can be achieved so far, a quality that already allows speaking of "ultra-fine" grinding. This results in remarkable possibilities to reduce conventional fine-machining procedures with loose abrasives. The fine grinded components can directly be polished to finally smooth the surface and remove remaining defects. Total-processing-times can be strongly reduced, involving significant economic advantages.

  8. Reducing the Edge Chipping for Capillary End Face Grinding and Polishing

    Directory of Open Access Journals (Sweden)

    Hošek J.

    2013-05-01

    Full Text Available This paper presents results of glass capillary end face grinding and polishing by approach that reduces the edge chipping. Brittle materials have natural tendency for edge chipping what leads to beveling the sharp edges. Not beveled sharp edges on glass capillary are important for special applications like surface tension measurement of small liquid samples. We use common grinding and polishing process for capillary end face machining modified with gradual decreasing of grinding load based on the relation of the critical chipping load. Achieved surface roughness is measured using atomic force microscopy (AFM. Capillary inner edge quality is checked both with optical microscopes and electron microscope too. We achieved a non-chipped capillary inner edge with radius down to 100 nm.

  9. Effect of Grinding Techniques on Absorbing Characteristics of Short Iron Fibers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Microwave-absorbing properties of iron fibers can be adjusted by their aspect ratio. This paper presents several modification techniques for grinding long iron fibers to a suitable aspect ratio. The grinding instruments include pulsator, jet mill and muller. The aspect ratio distribution, microstructure, electromagnetic parameter and refiectivity of the samples were analyzed and discussed in detail. The results show that the fractions of 5<aspect ratio<40 for the three methods are 69.03%, 81.11% and 80.2%, respectively, that is,suitable short iron fibers can be obtained by the jet mill and muller. Furthermore, the short iron fibers milled by jet mill and muller have better absorbing propterties than those obtained by the pulsator under the same condition. Therefore, their microwave absorption properties can be improved by regulating the electromagnetic parameters with grinding.

  10. The effect of moisture content on grinding process of wheat and maize single kernel

    Science.gov (United States)

    Lupu, M. I.; Pădureanu, V.; Canja, C. M.; Măzărel, A.

    2016-08-01

    The mechanical properties and the resistance of grains are key characteristics that enhance grinding behaviour of wheat and maize and are dependent on the moisture content of the grains. These properties were defined in the single-kernel compression test, and it seems that the qualities expressing the relations resulting during mechanical loads like mechanical and rheological properties are significant. The aim of the study reported here is to show the influence of moisture content on grinding process of wheat and maize single kernel. To show this influence it is necessary to study the physical and mechanical properties of wheat and maize single kernel at different moisture content 10%, 12%, 14%, 16%, 18% and 20%. The measurement results showed significant relationship between the cereal type, its resistance characteristics and the moisture content in the grinding process.

  11. Online monitoring of a belt grinding process by using a light scattering method

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Johannes; Vernes, Andras; Vorlaufer, Georg; Vellekoop, Michael

    2010-10-20

    Industrially ground surfaces often have a characteristic surface topography known as chatter marks. The surface finishing is mainly monitored by optical measurement techniques. In this work, the monitoring of an industrial belt grinding process with a light scattering sensor is presented. Although this technique is primarily applied for parametric surface roughness analysis, here it is shown that it enables also the measurement of the surface topography, i.e., the chatter marks occurring during the belt grinding process. In particular, it is proven that the light scattering method is appropriate to measure online the topography of chatter marks. Furthermore, the frequency analysis of the data reveals that the wavelength of chatter marks strongly depends on process parameters, such as the grinding speed.

  12. Rolling Resistance and Mechanical Properties of Grinded Copper Surfaces Using Molecular Dynamics Simulation

    Science.gov (United States)

    Liang, Shih-Wei; Wang, Chih-Hao; Fang, Te-Hua

    2016-09-01

    Mechanical properties of copper (Cu) film under grinding process were accomplished by molecular dynamics simulation. A numerical calculation was carried out to understand the distributions of atomic and slip vector inside the Cu films. In this study, the roller rotation velocity, temperature, and roller rotation direction change are investigated to clarify their effect on the deformation mechanism. The simulation results showed that the destruction of materials was increased proportionally to the roller rotation velocity. The machining process at higher temperature results in larger kinetic energy of atoms than lower temperature during the grinding process of the Cu films. The result also shows that the roller rotation in the counterclockwise direction had the better stability than the roller rotation in the clockwise direction due to significantly increased backfill atoms in the groove of the Cu film surface. Additionally, the effects of the rolling resistances on the Cu film surfaces during the grinding process are studied by the molecular dynamics simulation method.

  13. Rolling Resistance and Mechanical Properties of Grinded Copper Surfaces Using Molecular Dynamics Simulation.

    Science.gov (United States)

    Liang, Shih-Wei; Wang, Chih-Hao; Fang, Te-Hua

    2016-12-01

    Mechanical properties of copper (Cu) film under grinding process were accomplished by molecular dynamics simulation. A numerical calculation was carried out to understand the distributions of atomic and slip vector inside the Cu films. In this study, the roller rotation velocity, temperature, and roller rotation direction change are investigated to clarify their effect on the deformation mechanism. The simulation results showed that the destruction of materials was increased proportionally to the roller rotation velocity. The machining process at higher temperature results in larger kinetic energy of atoms than lower temperature during the grinding process of the Cu films. The result also shows that the roller rotation in the counterclockwise direction had the better stability than the roller rotation in the clockwise direction due to significantly increased backfill atoms in the groove of the Cu film surface. Additionally, the effects of the rolling resistances on the Cu film surfaces during the grinding process are studied by the molecular dynamics simulation method.

  14. Stress Analysis of a Three-Layer Metal Composite System of Bearing Assemblies During Grinding

    Science.gov (United States)

    Pashnyov, V. A.; Pimenov, D. Yu.

    2015-03-01

    A mathematical model of the stress state of a three-layer metal composite system caused by cutting forces during grinding the working layer of the system is elaborated. The implementation of the model by using the finite-element method made it possible to assess the effect of structure of the system, the deformation properties of layer materials, and grinding conditions on the distribution and level of normal and tangential stresses in layers, which determine the load-carrying capacity of the system. The results of an analysis of stress fields can serve as a basis for determining the grinding conditions ensuring retention of the load-carrying capacity of the metal composite system.

  15. Wheel wear and surface/subsurface qualities when precision grinding optical materials

    Science.gov (United States)

    Tonnellier, X.; Shore, P.; Luo, X.; Morantz, P.; Baldwin, A.; Evans, R.; Walker, D.

    2006-06-01

    An ultra precision large optics grinder, which will provide a rapid and economic solution for grinding large off-axis aspherical and free-form optical components, has been developed at Cranfield University. This paper presents representative grinding experiments performed on another machine - a 5 axes Edgetek - in order to verify the proposed BoX(r) grinding cycle. The optical materials assessed included; Zerodur(r), SIC and ULE(r), all three being materials are candidates for extreme large telescope (ELT) mirror segments. Investigated removal rates ranged from 2mm 3/s to 200mm 3/s. The higher removal rate ensures that a 1 metre size optic could be ground in less than 10 hours. These experiments point out the effect of diamond grit size on the surface quality and wheel wear. The power and forces for each material type at differing removal rates are presented, together with subsurface damage.

  16. Microwave-assisted grinding of metallurgical coke; Molienda asistida con microondas de un coque metalurgico

    Energy Technology Data Exchange (ETDEWEB)

    Ruisanchez, E.; Juarez-Perez, E. J.; Arenillas, A.; Bermudez, J. M.; Menendez, J. A.

    2014-10-01

    Metallurgical cokes are composed of graphitic carbon (s2p2) and different inorganic compounds with very different capacities to absorb microwave radiation. Moreover, due to the electric conductivity shown by the metallurgical cokes, microwave radiation produces electric arcs or microplasmas, which gives rise to hot spots. Therefore, when these cokes are irradiated with microwaves some parts of the particle experiment a rapid heating, while some others do not heat at all. As a result of the different expansion and stress caused by thermal the shock, small cracks and micro-fissures are produced in the particle. The weakening of the coke particles, and therefore an improvement of its grind ability, is produced. This paper studies the microwave-assisted grinding of metallurgical coke and evaluates the grinding improvement and energy saving. (Author)

  17. Extraction of Lithium from Lepidolite Using Mixed Grinding with Sodium Sulfide Followed by Water Leaching

    Directory of Open Access Journals (Sweden)

    Jaeryeong Lee

    2015-11-01

    Full Text Available Mixed grinding with Na2S followed by water leaching was performed to extract Li from lepidolite. The leachability of Li increases dramatically in the ground mixture, regardless of the mixing ratio over the range of 1:1 to 3:1, while only 4.53% of Li was extracted in lepidolite ground without Na2S. The leachability increased with an increase of the grinding time, and ultimately, 93% of the Li was leached by water from the ground mixture with a weight ratio of 3:1 (Na2S:Lepidolite. In the process of the mixed grinding, the Li-contained lepidolite was destructured crystallographically, and it might have changed to different compounds. This process enables us to extract Li from lepidolite via a water leaching treatment.

  18. Theoretical and experimental analysis on super precision grinding of monocrystal silicon

    Institute of Scientific and Technical Information of China (English)

    GUO Xiaoguang; GUO Dongming; KANG Renke; JIN Zhuji

    2007-01-01

    Through investigating the diamond-silicon grinding system,the grinding mechanism,including chip removal and subsurface damage,is discussed with the aid of the molecular dynamics(MD)approach and grinding experiments.Based on MD simulation,nanometric-grinding mechanism is analyzed from the viewpoint of instantaneous distribution of atoms,grinding force,and the potential energy between atoms and the profile of the groove.The simulation results show that some silicon atoms are deformed and piled up in front and on two sides of the abrasive surface because of the extrusion and cutting.When the energy in silicon lattice reaches its maximum value,the bonds of silicon atoms are broken and the material is removed.With the advancement of the abrasive,the silicon lattice under the abrasive surface is fractured,and then the amorphous layers are formed and propagated,which causes the subsurface damage.At the same time,some amorphous atoms are reconstructed and the degenerating layer of the machined surface is formed.Besides,the recovery of elatstic deformation occurs in the machined surface of the workpiece.In addition,the grinding experiment and profile detection with the aid of the measurment for 3D profiling are performed to verify the simulation results.The good agreement in the profile of the groove between the experimental value and the simulating value shows that MD simulation is very effective and reliable,and successful to fulfill the investigation on nanometric machining mechanism.

  19. Simulation and Experimental Analysis of Super High-Speed Grinding of Ductile Material

    Institute of Scientific and Technical Information of China (English)

    SHIMIZU; Jun; EDA; Hiroshi

    2002-01-01

    This study aims to reduce the work-affected layer of the machined surface by carrying out the grinding at the speed over static pr o pagation speed of plastic wave of ductile materials and also aims to clarify suc h super high-speed machining mechanism.This paper reports on the result obtain ed through the molecular dynamics simulations and experiments on the super-spee d grinding below and beyond static propagation speed of aluminum.From the simul ation results,it is verified that the plastic deformation ...

  20. Development of a Wire Driven Robot for Grinding with Stiffness Adapted

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Along with development of new design and machining me thod production with more complex surface can be manufactured. Researching on th e new equipment used for surface disposal has become the important matter. Grind ing and polishing are a common surface processing method. A new type wire driven parallel robot used for grinding processing is proposed in this paper. Wire driven parallel robot is developed from parallel robot and serial wire driven r obot. Steel wire is used to replace the leg of paralle...

  1. Surface Waviness in Grinding of Thin Mould Insert Using Chilled Air as Coolant

    Institute of Scientific and Technical Information of China (English)

    Yeo; S; H; K; Ramesh

    2002-01-01

    On going trend of miniaturization in electronic rel at ed parts, which is an average of two times in every 5~7 years introduce grindin g challenges. In grinding process, the surface waviness control of thin parts is an ardent task due to its warpage, induced by the high specific grinding energy (2~10 J/mm 3). Therefore, coolant is often used to avoid thermal damage, obtai n better surface integrity and to prolong wheel life. However coolant, the incomp ressibility media introduce high forces at the gri...

  2. A Facile Solvent Free Synthesis of 3-arylidenechroman-4-ones Using Grinding Technique

    Directory of Open Access Journals (Sweden)

    Suresh Kumar

    2012-01-01

    Full Text Available An efficient method for the synthesis of 3-arylidenechroman-4-ones has been developed under solvent free conditions using grinding technique. Grinding of variously substituted chroman-4-ones with aromatic aldehydes in presence of anhydrous barium hydroxide at room temperature give 3-arylidenechroman-4-ones in high yield (75-92%. Products are obtained by just acidification of the reaction mixture in ice cold water. Reaction in solid state, with enhanced rate, high selectivity and manipulative simplicity are the attractive features of this environmentally benign protocol. The chroman-4-one derivatives required for the reaction have been obtained by polyphosphoric acid (PPA catalysed cyclisation of phenoxypropanoic acids under microwave irradiations.

  3. INFLUENCE OF OSCILLATORY IMPACT ON MOVEMENT IN LIQUID AND GRINDING OF WOOD PULP USED FOR PACKAGING PRODUCTION

    Directory of Open Access Journals (Sweden)

    I. I. Karpunin

    2011-01-01

    Full Text Available The paper investigates an influence of oscillatory impacts on wood pulp grinding which is used for packaging production.It has been established that plate oscillatory impact promotes better quality of the obtained paper sheet made of grind plant fiber.

  4. THEORETICAL AND EXPERIMENTAL STUDIES OF ENERGY-EFFICIENT GRINDING PROCESS OF CEMENT CLINKER IN A BALL MILL

    Directory of Open Access Journals (Sweden)

    Kuznetsova M.M.

    2014-08-01

    Full Text Available The article presents results of theoretical and experimental research of grinding process of bulk materials in a ball mill. The new method of determination of energy efficiently mode of operation of ball mills in a process of a cement clinker grinding is proposed and experimentally tested.

  5. Study on cermet CBN grinding wheels for ultra-precision grinding%一种新型超精磨金属陶瓷CBN砂轮的研究

    Institute of Scientific and Technical Information of China (English)

    陈卫东; 韩云

    2012-01-01

    通过考察不同因素对砂轮锋利性、寿命及加工工件表面粗糙度的影响,优选出了端面超精磨CBN砂轮的制备工艺.通过对比实验,得出最优配比如下:CBN磨料的粒径优选添加40 μm,陶瓷空心球的粒度优选添加240目,其添加量优选体积分数为20%,金属粉的优选体积分数为9%.该配方制备的CBN砂轮的锋利性、寿命及加工工件的表面粗糙度均达到了较好的效果.%By studying main influence factors on wheel sharpness, lifetime and machined surface roughness of workpieces, optimum manufacturing technology of cermet CBN grinding wheel for end ultra-precision grinding was researched. After a series of comparative experiments, optimized manufacturing parameters were obtained as follows; particle size of CBN grits 40 μm; hollow ceramic sphere size 240 meshes with addition amount 20% (volume fraction) ; and volume fraction of metal powder 9%. CBN grinding wheels prepared according to the formula above showed better properties, such as sharpness, lifespan and surface roughness of machined workpieces.

  6. Effect of ultrafine grinding on physicochemical and antioxidant properties of dietary fiber from wine grape pomace.

    Science.gov (United States)

    Zhu, Feng-Mei; Du, Bin; Li, Jun

    2014-01-01

    Wine grape pomace dietary fiber powders were prepared by superfine grinding, whose effects were investigated on the composition, functional and antioxidant properties of the wine grape pomace dietary fiber products. The results showed that superfine grinding could effectively pulverize the fiber particles to submicron scale. As particle size decrease, the functional properties (water-holding capacity, water-retention capacity, swelling capacity, oil-binding capacity, and nitrite ion absorption capacity) of wine grape pomace dietary fiber were significantly (p fiber components from insoluble to soluble fractions was observed. The antioxidant activities of wine grape pomace and dietary fiber before and after grinding were in terms of DPPH radical scavenging activity, ABTS diammonium salt radical scavenging activity, ferric reducing antioxidant power, and total phenolic content. Compared with dietary fiber before and after grinding, micronized insoluble dietary fiber showed increased ABTS radical scavenging activity, ferric reducing antioxidant power, and total phenolic content yet decreased DPPH radical scavenging activity. Positive correlations were detected between ABTS radical scavenging activity, ferric reducing antioxidant power, and total phenolic content.

  7. Electrochemical properties and Li deposition morphologies of surface modified graphite after grinding

    Science.gov (United States)

    Honbo, H.; Takei, K.; Ishii, Y.; Nishida, T.

    Electrochemical properties and Li deposition morphologies of several kinds of carbon with different surfaces were studied. The surface conditions and Li deposition morphologies were analyzed using Raman spectroscopy and scanning electron microscopy. It appeared that the disordered carbon surface suppressed the Li dendrite deposition. Grinding methods with different clearances were adopted to modify the graphite into a desirable surface. The R-value increased from 0.10 to 0.63 after grinding to 40 μm, though a significant change in d 0 0 2 did not occur. These results suggest that disordered carbon was created on the surface without a significant change in bulk crystallinity. Thus, the reversible capacity, which is about 350 mAh g -1, was the same before and after grinding. However, the Li deposition morphologies significantly changed before and after grinding. The pristine graphite had a dendritic morphology, but the ground graphite had a granular morphology. It is believed that the defects on the disordered carbon act as electrodeposition nuclei and prevent the formation of Li dendrites.

  8. Synthesis of bimetallic gold-silver alloy nanoclusters by simple mortar grinding.

    Science.gov (United States)

    Murugadoss, Arumugam; Kai, Noriko; Sakurai, Hidehiro

    2012-02-21

    A macroscale quantity of bimetallic Au-Ag alloy nanoclusters was achieved through sequential reduction by simple mortar grinding. The chitosan biopolymer was used as both a stabilizing and reducing agent. These nanoclusters exhibit excellent catalytic activity toward the reduction of 4-nitrophenol.

  9. Determining the optimum process parameter for grinding operations using robust process

    Energy Technology Data Exchange (ETDEWEB)

    Neseli, Suley Man; Asilturk, Ilhan; Celik, Levent [Univ. of Selcuk, Konya (Turkmenistan)

    2012-11-15

    We applied combined response surface methodology (RSM) and Taguchi methodology (TM) to determine optimum parameters for minimum surface roughness (Ra) and vibration (Vb) in external cylindrical grinding. First, an experiment was conducted in a CNC cylindrical grinding machine. The TM using L{sup 27} orthogonal array was applied to the design of the experiment. The three input parameters were workpiece revolution, feed rate and depth of cut; the outputs were vibrations and surface roughness. Second, to minimize wheel vibration and surface roughness, two optimized models were developed using computer aided single objective optimization. The experimental and statistical results revealed that the most significant grinding parameter for surface roughness and vibration is workpiece revolution followed by the depth of cut. The predicted values and measured values were fairly close, which indicates 2 ( 94.99 R{sup 2Ra}=and 2 92.73) R{sup 2Vb}=that the developed models can be effectively used to predict surface roughness and vibration in the grinding. The established model for determination of optimal operating conditions shows that a hybrid approach can lead to success of a robust process.

  10. Kinematic equations to grind a helical drill point on a virtual axis drill sharpener

    Institute of Scientific and Technical Information of China (English)

    陈五一; 陈鼎昌

    2000-01-01

    The basic structure of a virtual axis drill grinder is presented in terms of the spatial vectors and thegrinding parameters calculated according to the geometry of a helical drill point. The kinematic equations for sharpening the drills on the virtual axis grinder are deduced using the grinding parameters via vector-matrix txansformation.

  11. Mist-jetting Electrical Discharge Dressing Technology for Superabrasive Grinding Wheels

    Institute of Scientific and Technical Information of China (English)

    CAI Lan-rong; HU De-jin; JIA yan

    2008-01-01

    The technology of superabrasive grinding has been developed in order to achieve high-quality finish in extremely hard and brittle materials.Thereafter,truing and dressing technology on super abrasive grinding wheel is one of the most important subjects on precise machining field at present.In this paper,mist-jetting electrical discharge technology was applied to dressing metai-bonded superabrasive wheels.And a systematical study on the mechanism of selective removal of the bond was proposed.Experiments on dressing bronze bonded diamond grind wheels were carried out on a die-sinking electrical discharge machine.The diamond wheel topographies before and after electrical discharge dressing were observed by VH-800 3D digital microscope.The wheel profiles before and after dressing were observed.The results of electrical discharge dressing under different electrical parameters were compared.Experimental results indicate that the favorable surface topography can be obtained under suitable processing parameters and mist-jetting electrical discharge dressing (MEDD) is feasible for metal-bonded diamond grinding wheel.

  12. Determination of the scheme of precision grinding compensation on the radome

    Institute of Scientific and Technical Information of China (English)

    GUO Dongming; LIU Minjing; ZHANG Chunbo; SHENG Xianjun; SUN Yuwen

    2007-01-01

    The radome,which is often used to house airborne scanning radar antennas,causes a large boresight error and boresight error slope of the radar antenna.One way to decrease the boresight error induced by the radome is to modify its geometric thickness.Determining the grinding scheme from the boresight error performance is the most important problem to be solved.A typical inverse problem about electromagnetic fields is solving the precise grinding compensation area and allowance according to the antenna aperture distribution and the radome's boresight error performance,which could hardly be solved by a purely mathematical method.An effective approach combining theoretical analysis and mathematical calculations with experimental measurement is presented in this paper to determine the grinding area and allowance for compensating the boresight error performance of the radome.By comparing the calculated and measured data of the boresight error and the boresight error slope before and after grinding,it is shown that this method is simple and practical and can be used for many kinds of radomes.

  13. Experimental Analysis & Optimization of Cylindirical Grinding Process Parameters on Surface Roughness of En15AM Steel

    Directory of Open Access Journals (Sweden)

    Sandeep Kumar

    2015-07-01

    Full Text Available As per the modern Industrial requirements, higher surface finish mechanical components and mating parts with close limits and tolerances, is one of the most important requirement. Abrasive machining processes are generally the last operations performed on manufactured products for higher surface finishing and for fine or small scale material removal. Higher surface finish and high rate of removal can be obtained if a large number of grains act together. This is accomplished by using bonded abrasives as in grinding wheel or by modern machining processes. In the present study, Taguchi method or Design of experiments has been used to optimize the effect of cylindrical grinding parameters such as wheel speed (rpm, work speed, feed (mm/min., depth of cut and cutting fluid on the surface roughness of EN15AM steel. Ground surface roughness measurements were carried out by Talysurf surface roughness tester. EN15AM steel has several industrial applications in manufacturing of engine shafts, connecting rods, spindles, studs, bolt, screws etc. The results indicated that grinding wheel speed, work piece speed, table feed rate and depth of cut were the significant factors for the surface roughness and material removal rate. Surface roughness is minimum at 2000 r.p.m. of grinding wheel speed , work piece speed 80 rpm, feed rate 275 mm/min. and 0.06 mm depth of cut.

  14. Single Side Electrolytic In-Process Dressing (ELID) Grinding with Lapping Kinematics of Silicon Carbide

    Science.gov (United States)

    Khoshaim, Ahmed Bakr

    The demand for Silicon Carbide ceramics (SiC) has increased significantly in the last decade due to its reliable physical and chemical properties. The silicon carbide is widely used for aerospace segments in addition to many uses in the industry. Sometimes, a single side grinding is preferable than conventional grinding, for it has the ability to produce flat ceramics. However, the manufacturing cost is still high because of the high tool wear and long machining time. Part of the solution is to use electrolytic in process dressing (ELID) to reduce the processing time. The study on ELID single side grinding of ceramics has never been attempted before. The study involves four variables with three levels each. One of the variables, which is the eccentricity, is being investigated for the first time on ceramics. A full factorial design, for both the surface roughness and material removal rate, guides to calculate mathematical models that can predict future results. Three grinding wheel mesh sizes are used. An investigation of the influence of different grain size on the results can then be evaluated. The kinematics of the process was studied based on eccentricity in order to optimize the pattern of the diamond grains. The experiment is performed with the assist of the proposed specialized ELID fluid, TRIM C270E.

  15. New technique for preparing cartilage for intracordal injection: the freezing and grinding method.

    Science.gov (United States)

    Park, Young Min; Lee, Won Yong; Lim, Yun-Sung; Lee, Jin-Choon; Lee, Byung-Joo; Wang, Soo-Geun

    2014-07-01

    We developed a technique for preparing harvested cartilage that creates finer, more uniform pieces by freezing with liquid nitrogen and grinding with a mortar and pestle. Herein, we report the application of this new technique for intracordal cartilage injection. Experimental study. Human cartilage was obtained from surgical cases. In the standard method, harvested cartilage was prepared with scissors and a knife. In the experimental group, harvested cartilage was frozen with liquid nitrogen and ground with a mortar and pestle. It took an average of 60 minutes to manipulate cartilage using the standard technique, whereas it took an average of 10 minutes using the freezing and grinding method (P<0.001). The average size of cartilage flakes generated by the standard and new techniques were 727 and 48.6 μm, respectively. The cartilage flakes produced using scissors and a knife were able to pass through a 19-gauge needle, whereas those created using the freezing and grinding method were able to pass through a 24-gauge needle. Using the freezing and grinding method, cartilage was broken into fine, uniform pieces that could pass through a 24-gauge needle. This new technique will facilitate the production of commercial cartilage material for intracordal injection. Copyright © 2014 The Voice Foundation. All rights reserved.

  16. STIMULATION OF PROCESS OF MUNERAL POWDER GRINDING THROUGH INTRODUCTION OF ADMIXTURES

    Directory of Open Access Journals (Sweden)

    Tarasov Roman Viktorovich

    2012-10-01

    Full Text Available The status of nanotechnologies in material science predetermines development of nanotechnology-intensive products that demonstrate pre-set properties of modified materials. The presence of nano-size particles of substances makes it possible to benefit from their physical and chemical potential and to overcome some negative developments that accompany the structure formation process (at interphase boundaries. The barrier properties are variable, which is quite important in terms of the increase of the asphalt concrete durability. Production of a modifier (that has nano-particles of the pre-set chemical composition to be added into asphalt concrete mixes is also of interest. The authors present their findings concerning the nano-scale modifier that has a chemically inert component and a hydraulically active substance. The method of de-aggregation is used to produce the nano-scale modifier. By-products are often welcomed as mineral components of the asphalt concrete, as they reduce its cost. The findings of the authors concerning the influence of the grinding mode on the integrated characteristics of the powder are presented in the paper. It is proven than dependence of integrated dispersion indicators is nonlinear due to processes leading to aggregation of mineral powder particles. The analysis of the experimental data collected in the course of "wet" grinding proves that surface-active substances stimulate the process of grinding. The type and concentration of an additive that improves the grinding efficiency is also identified.

  17. Robustness of a cross contamination model describing transfer of pathogens during grinding of meat

    DEFF Research Database (Denmark)

    Møller, Cleide Oliveira de Almeida; Sant’Ana, A. S.; Hansen, Solvej Katrine Holm

    2016-01-01

    This study aimed to evaluate a cross contamination model for its capability of describing transfer of Salmonella spp. and L. monocytogenes during grinding of varying sizes and numbers of pieces of meats in two grinder systems. Data from 19 trials were collected. Three evaluation approaches were...

  18. Robustness of a cross contamination model describing transfer of pathogens during grinding of meat

    DEFF Research Database (Denmark)

    Møller, Cleide Oliveira de Almeida; Sant’Ana, A. S.; Hansen, Solvej Katrine Holm

    2016-01-01

    This study aimed to evaluate a cross contamination model for its capability of describing transfer of Salmonella spp. and L. monocytogenes during grinding of varying sizes and numbers of pieces of meats in two grinder systems. Data from 19 trials were collected. Three evaluation approaches were...

  19. Ultra-precision ductile grinding of BK7 using super abrasive diamond wheel

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qingliang; Brinksmeier Ekkard; Riemer Oltmann; Rickens Kai

    2007-01-01

    In this paper,a novel conditioning technique using copper bonded diamond grinding wheels of 91 μm grain size and electrolytic in-process dressing (ELID) is first developed to precisely and effectively condition a nickelelectroplated monolayer coarse-grained diamond grinding wheel of 151 μm grain size.Under optimised conditioning parameters,the super abrasive diamond wheel was well conditioned in terms of a minimized run-out error and flattened diamond grain surfaces of constant peripheral envelope.The conditioning force was monitored by a force transducer,while the modified wheel surface status was in-situ monitored by a coaxial optical distance measurement system.Finally,the grinding experiment on BK7 was conducted using the well-conditioned wheel with the corresponding surface morphology and subsurface damage measured by atomic force microscope (AFM) and scanning electric microscope (SEM),respectively.The experimental result shows that the newly developed conditioning technique is applicable and feasible to ductile grinding optical glass featuring nano scale surface roughness,indicating the potential of super abrasive diamond wheels in ductile machining brittle materials.

  20. DRY AND WET GRINDING KINETICS OF CHROMIUM ORE AND EFFECT OF PULP DENSITY

    Directory of Open Access Journals (Sweden)

    Alper ÖZKAN

    2006-01-01

    Full Text Available In this study, the kinetics of dry and wet grinding of various feed sizes of chromium ore has been determined using a laboratory scale ceramic ball mill. In addition, the effect of pulp density on the spesific rate of breakage (Si and net production rate to finer than specified size were investigated. The dry and wet grinding of all the size intervals of chromium ore followed the first-order breakage law, and the Si values increased as the feed sizes became coarser. Moreover, the wet grinding of these various feed sizes gave higher Si values by a factor of 2.0 to 2.6 comparing to the dry Si values. From the experimental studies performed on the effect of pulp density on the grinding process, the highest Si value was obtained at a pulp density of 45 % solids by volume. At the same pulp density value, the rate of net production of -75 µm particle size also reached the highest value.

  1. Investigation on the potential of waste cooking oil as a grinding aid in Portland cement.

    Science.gov (United States)

    Li, Haoxin; Zhao, Jianfeng; Huang, Yuyan; Jiang, Zhengwu; Yang, Xiaojie; Yang, Zhenghong; Chen, Qing

    2016-12-15

    Although there are several methods for managing waste cooking oil (WCO), a significant result has not been achieved in China. A new method is required for safe WCO management that minimizes the environmental threat. In this context, this work was developed in which cement clinker and gypsum were interground with various WCOs, and their properties, such as grindability, water-cement ratio required to achieve a normal consistency, setting times, compressive strength, contents of calcium hydroxide and ettringite in the hardened paste, microstructure and economic and environmental considerations, were addressed in detail. The results show that, overall, WCO favorably improves cement grinding. WCO prolonged the cement setting times and resulted in longer setting times. Additionally, more remarkable effects were found in cements in which WCO contained more unsaturated fatty acid. WCOs increased the cement strength. However, this enhancement was rated with respect to the WCO contents and components. WCOs decreased the CH and AFt contents in the cement hardened paste. Even the AFt content at later ages was reduced when WCO was used. WCO also densify microstructure of the hardened cement paste. It is economically and environmentally feasible to use WCOs as grinding aids in the cement grinding process. These results contribute to the application of WCOs as grinding aids and to the safe management of WCO. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Electrophoretic deposition grinding (EPDG) for improving the precision of microholes drilled via ECDM

    Science.gov (United States)

    Yan, Biing-Hwa; Yang, Ching-Tang; Huang, Fuang-Yuan; Lu, Zhe-Hong

    2007-02-01

    Electrochemical discharge machining (ECDM) is an alternative method to microdrill Pyrex glass for MEMS devices. However, the taper and the heat-affected zone of the microholes resulting from the thermal energy is a problem to which attention has to be paid. This study attempts to improve the ECDMed microhole quality by applying electrophoretic deposition grinding (EPDG). ECDM was first used to drill a microhole and was followed by EPDG to refine the hole. The experimental results demonstrated that selecting a suitable diameter of the tool in EPDG is important to improve the taper angle of microholes machined by ECDM. A step shape tool with phi210 µm diameter was designed as a critical factor for improving the taper. An excellent taper angle of 0.2° could be achieved. At the beginning of EPDG, the taper angle and wavy surface of the ECDMed hole were improved by the step shape tool. The subsequent EPDG further improved the surface roughness. Additionally, a sufficient grinding time was required to produce a fine surface. Improving surface roughness requires a higher tool rotation speed and a longer grinding time. However, the dislodging of abrasives in the entrance will worsen the roundness and increase the diameter difference of the hole. Suitable grinding parameters for use in the experiments include tool rotation speed: 1500 rpm, abrasive size: 0.3 µm and grinding time: 500 s. After EPDG, the surface roughness of the microholes achieved was 5 nm Ra. This study demonstrates the feasibility of using EPDG to improve the quality of the ECDMed hole.

  3. Anterior temporalis and suprahyoid EMG activity during jaw clenching and tooth grinding.

    Science.gov (United States)

    Aldana, Karina; Miralles, Rodolfo; Fuentes, Aler; Valenzuela, Saúl; Fresno, María Javiera; Santander, Hugo; Gutiérrez, Mario Felipe

    2011-10-01

    The aim of this study was to evaluate the anterior temporalis and suprahyoid electromyographic (EMG) activity during jaw clenching and tooth grinding at different jaw posture tasks. The study included 30 healthy subjects with natural dentition and bilateral molar support, incisive protrusive guidance and bilateral laterotrusive canine guidance. Bipolar surface electrodes were located on the right anterior temporalis and suprahyoid muscles. Three EMG recordings in the standing position were performed in the following tasks: C. clenching in the intercuspal position (IP); P1. eccentric grinding from IP to protrusive edge-to-edge contact position; P2. clenching in protrusive edge-to-edge contact position; P3. concentric grinding from protrusive edge-to-edge contact position to IP; L1. eccentric grinding from IP to laterotrusive edge-to-edge contact position; L2. clenching in laterotrusive edge-to-edge contact position; L3. concentric grinding from laterotrusive edge-to-edge contact position to IP. EMG activity during protrusive and laterotrusive tasks was lower than intercuspal position in the anterior temporalis, whereas an opposite EMG pattern was observed in the suprahyoid muscles activity, excepting recorded activity in L2 (mixed model with unstructured covariance matrix). Anterior temporalis activity was higher during P3 than P1 and P2 tasks and during L3 than L1 and L2 tasks, whereas in the suprahyoid muscles, activity was higher during P1 than P2 tasks and during L1 than L2 and L3 tasks. These results could support the idea of a differential modulation of the motor neuron pools of anterior temporalis and suprahyoid muscles of peripheral and/or central origin.

  4. Automatic detection of thermal damage in grinding process by artificial neural network

    Directory of Open Access Journals (Sweden)

    Fábio Romano Lofrano Dotto

    2003-12-01

    Full Text Available This work aims to develop an intelligent system for detecting the workpiece burn in the surface grinding process by utilizing a multi-perceptron neural network trained to generalize the process and, in turn, obtnaing the burning threshold. In general, the burning occurrence in grinding process can be detected by the DPO and FKS parameters. However, these ones were not efficient at the grinding conditions used in this work. Acoustic emission and electric power of the grinding wheel drive motor are the input variable and the output variable is the burning occurrence to the neural network. In the experimental work was employed one type of steel (ABNT-1045 annealed and one type of grinding wheel referred to as TARGA model ART 3TG80.3 NVHB.Esse trabalho tem por objetivo o desenvolvimento de um sistema inteligente para detecção da queima no processo de retificação tangencial plana através da utilização de uma rede neural perceptron multi camadas, treinada para generalizar o processo e, conseqüentemente, obter o limiar de queima. Em geral, a ocorrência da queima no processo de retificação pode ser detectada pelos parâmetros DPO e FKS. Porém esses parâmetros não são eficientes nas condições de usinagem usadas nesse trabalho. Os sinais de emissão acústica e potência elétrica do motor de acionamento do rebolo são variáveis de entrada e a variável de saída é a ocorrência da queima. No trabalho experimental, foram empregados um tipo de aço (ABNT 1045 temperado e um tipo de rebolo denominado TARGA, modelo ART 3TG80.3 NVHB.

  5. Surface quality of a 1m Zerodur part using an effective grinding mode

    Science.gov (United States)

    Tonnellier, X.; Shore, P.; Morantz, P.; Orton, D.

    2008-09-01

    A new ultra precision large optics grinding machine, BoX (R) , has been developed at Cranfield University. This machine is located at the UK's Ultra Precision Surfaces laboratory at the OpTIC Technium, North Wales. This machine offers a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. This paper presents an analysis of surface and subsurface damage assessments of Zerodur(R) ground using diamond resin bonded grinding wheels. Zerodur(R) was tested as it is one of the materials currently under study for making extremely large telescope (ELT) segmented mirrors such as in the E-ELT project. The grinding experiments have been conducted on the BoX(R) grinding machine using wheels with grit sizes of 76 μm, 46 µm and 25 μm. The highest material removal rate (187.5 mm3/s) used ensures that a 1 metre diameter optic can be ground in less than 10 hours. The surface roughness and surface profile were measured using a Form Talysurf. The subsurface damage was revealed using a sub aperture polishing process in combination with an etching technique on small parts. These results are compared with the targeted form accuracy of 1 μm p-v over a 1 metre part, surface roughness of 50-150 nm RMS and subsurface damage in the range of 2-5 μm. This process stage was validated on a 1 metre hexagonal Zerodur(R) part.

  6. Ibuprofen-Amino Acids Co-Crystal Screening Via Co-Grinding Methods

    Directory of Open Access Journals (Sweden)

    Othman Muhamad Fitri

    2016-01-01

    Full Text Available The importance of pharmaceutical co-crystals now has been recognized in order to improve the research and development in pharmaceutical industries. Low solubility of active pharmaceutical ingredient (API has led to the growth of new pharmaceutical co-crystals formation as it enhances the physicochemical properties of the API. In this works, preparation of new co-crystal formation between ibuprofen (IBP with selected amino acid compounds were performed by using dry grinding and liquid assisted grinding (LAG techniques. Ibuprofen (IBP was selected as the API meanwhile glycine (GLY, L-alanine (ALA and L-proline (PRO were selected as co-crystal former (CCF agents. The products of IBP-co-former from grinding experiments for the formation of co-crystals were characterized and verified using X-Ray Powder Diffraction (XRPD, Differential Scanning Calorimetry (DSC and Fourier Transform Infra-Red Spectroscopy (FTIR. The finding reveals that the IBP-PRO co-crystals have successfully formed. For IBP-PRO system, new crystalline peaks from XRPD were recorded at 2θ values of 4.374°, 5.436° and 10.944° from dry grinding technique and 4.41°, 5.436° and 10.962° for liquid assisted grinding (LAG technique. A new melting point of 257.49 °C was discovered for IBP-ALA indicates the possibility of co-crystals formation. On the other hand, the analysis for IBP-GLY shows that no co-crystals formed in the system.

  7. Effect of grinding wheel granularity on the grinding-hardened layer of 42CrMo steel%砂轮粒度对42CrMo钢磨削强化层的影响

    Institute of Scientific and Technical Information of China (English)

    时海芳; 刘波; 马壮; 刘克铭

    2011-01-01

    在精密卧式磨床M7132A上,利用磨削加工产生的大量磨削热对磨削加工表面进行淬火处理.采用砂轮作为磨削淬火的加工工具,研究不同粒度的刚玉砂轮对42CrMo钢进行磨削淬火试验及强化层的组织和硬度的影响.结果表明:随着砂轮粒度的减小,距加工表面的强化层组织越细小;强化层的显微硬度分布曲线基本相同,但是距强化层至加工表面0.25 mm时,随着砂轮粒度的减小,强化层显微硬度增大,磨削强化层厚度增加.%Grinding heat generated from grinding was used to do hardening treatment for grinding machining surface on horizontal precision grinder (M7132A). The grinding wheel was used as grind-hardening machining tool to study the influence of grinding wheel granularity on microstructure and hardness of strengthened layer of 42CrMo. The results show that with the decrease of the particle size of grinding wheel, microstructure of strengthened layer on machined surface is fine. The microhardness distribution curve of strengthened layer is basicly same, but when the strengthened layer is 0.25 mm away from the machined surface, the decrease of particle size of grinding wheel will lead to the increase of microhardness of strengthened layer. Thickness of the grinding-strengthened layer increases.

  8. Residual stresses generated in F-522 steel by different machining processes; Tensiones residuales generadas en acero F-522 por distintos tipos de mecanizado

    Energy Technology Data Exchange (ETDEWEB)

    Gracia-Navas, V.; Ferreres, I.; Maranon, J. A.; Garcia-Rosales, C.; Gil-Sevillano, J.

    2005-07-01

    Machining operations induce plastic deformation and heat generation in the near surface area of the machined part, giving rise to residual stresses. Depending on their magnitude and sign, these stresses can be detrimental or beneficial to the service life of the part. The final stress state depends on the machining process applied, as well as on the machining parameters. Therefore, the establishment of adequate machining guidelines requires the measurement of the residual stresses generated both at the surface and inside the material. in this work, the residual stresses generated in F-522 steel by two hard turning (conventional and laser assisted) and two grinding (production and finishing) processes were measured by X-ray diffraction. Additionally, depth profiles of the volume fraction of retained austenite, microstructure and nano hardness were obtained in order to correlate those results with the residual stress state obtained for each machining process. It has been observed that turning generates tensile stresses in the surface while grinding causes compressive stresses. Below the surface grinding generates weak tensile or nearly null stresses whereas turning generates strong compressive stresses. These results show that the optimum mechanising process (disregarding economical considerations) implies the combination of turning plus elimination of a small thickness by final grinding. (Author) 19 refs.

  9. Residual Stress in Brazing of Submicron Al2O3 to WC-Co

    Science.gov (United States)

    Grunder, T.; Piquerez, A.; Bach, M.; Mille, P.

    2016-07-01

    This study evaluated the residual stresses induced by brazing and grinding submicron Al2O3, using different methods. Energy dispersive x-ray spectrometry analysis (EDX) of 72Ag-Cu filler and filler/WC-Co interface showed evidence of atomic diffusion and possible formation of titanium oxide layers between the joint and the bonding materials. An analytical model supported by the finite element method (FEM) based on strain determination due to the difference in variation of thermal expansion was used to assess the stress distribution at the coupling interface and in bulk materials. The model took into account the evolution of the Young's modulus and of the thermal expansion with temperature. The model could be used to follow strain and stress evolutions of the bonded materials during the cooling cycle. The maximum stress rose above -300 MPa at the center of the 100 × 100 × 3 mm ceramic plates. The residual stresses on the external surface of ceramic were investigated by x-ray diffraction (XRD) and indentation fracture method (IFM). After brazing and grinding the plate, the principal stresses were 128.1 and 94.9 MPa, and the shear stress was -20.1 MPa. Microscopic examination revealed grain pull-out promoted by the global residual stresses induced by the brazing and grinding processes. The surface stresses evaluated by the different methods were reasonably correlated.

  10. The grinding tip of the sea urchin tooth exhibits exquisite control over calcite crystal orientation and Mg distribution.

    Science.gov (United States)

    Ma, Yurong; Aichmayer, Barbara; Paris, Oskar; Fratzl, Peter; Meibom, Anders; Metzler, Rebecca A; Politi, Yael; Addadi, Lia; Gilbert, P U P A; Weiner, Steve

    2009-04-14

    The sea urchin tooth is a remarkable grinding tool. Even though the tooth is composed almost entirely of calcite, it is used to grind holes into a rocky substrate itself often composed of calcite. Here, we use 3 complementary high-resolution tools to probe aspects of the structure of the grinding tip: X-ray photoelectron emission spectromicroscopy (X-PEEM), X-ray microdiffraction, and NanoSIMS. We confirm that the needles and plates are aligned and show here that even the high Mg polycrystalline matrix constituents are aligned with the other 2 structural elements when imaged at 20-nm resolution. Furthermore, we show that the entire tooth is composed of 2 cooriented polycrystalline blocks that differ in their orientations by only a few degrees. A unique feature of the grinding tip is that the structural elements from each coaligned block interdigitate. This interdigitation may influence the fracture process by creating a corrugated grinding surface. We also show that the overall Mg content of the tooth structural elements increases toward the grinding tip. This probably contributes to the increasing hardness of the tooth from the periphery to the tip. Clearly the formation of the tooth, and the tooth tip in particular, is amazingly well controlled. The improved understanding of these structural features could lead to the design of better mechanical grinding and cutting tools.

  11. Closed-Loop Feedback Flank Errors Correction of Topographic Modification of Helical Gears Based on Form Grinding

    Directory of Open Access Journals (Sweden)

    Huiliang Wang

    2015-01-01

    Full Text Available To increase quality, reduce heavy-duty gear noise, and avoid edge contact in manufacturing helical gears, a closed-loop feedback correction method in topographic modification tooth flank is proposed based on the gear form grinding. Equations of grinding wheel profile and grinding wheel additional radial motion are derived according to tooth segmented profile modification and longitudinal modification. Combined with gear form grinding kinematics principles, the equations of motion for each axis of five-axis computer numerical control forming grinding machine are established. Such topographical modification is achieved in gear form grinding with on-machine measurement. Based on a sensitivity analysis of polynomial coefficients of axis motion and the topographic flank errors by on-machine measuring, the corrections are determined through an optimization process that targets minimization of the tooth flank errors. A numerical example of gear grinding, including on-machine measurement and closed-loop feedback correction completing process, is presented. The validity of this flank correction method is demonstrated for tooth flank errors that are reduced. The approach is useful to precision manufacturing of spiral bevel and hypoid gears, too.

  12. The grinding of uranium dioxide from fluidized beds; Estudio del m icronizado del UO{sub 2} procedente de lechos Fluidizados

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Folgueras, J. A.

    1974-07-01

    This work deals with the UO{sub 2} vibratory grinding, the UO{sub 2} obtained from fluidized beds. In this study the grinding time has been correlated with surface area, stoichiometry, granulometry and grinded product contamination. The efficiency losses in the grinding of moisten UO{sub 2} are outlined. Finally it is made a brief study of the granulate obtained from the grinded UO{sub 2} as well as the green pellets resulting from it, taking into consideration the dispersion of its density and height. (Author)

  13. Simulation of Flow and Heat Transfer of Mist/Air Impinging Jet on Grinding Work-Piece

    OpenAIRE

    Fan Jiang; Han Wang; Yijun Wang; Jianhua Xiang

    2016-01-01

    The numerical investigation is presented for flow and heat transfer on grinding work-piece with mist/air impinging jet by using DPM (discrete phase model) model. The tracks of the mist droplets show most of them are accumulated on the right surface of grinding zone, and can be influenced by the rotating speed of the grinding wheel, the position and the number of the jet nozzle. The mechanism model of enhance cooling by mist/air impinging jet is developed, which indicated the mist droplet is a...

  14. Effectiveness of dust control methods for crystalline silica and respirable suspended particulate matter exposure during manual concrete surface grinding.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Milz, Sheryl A; Wagner, Cynthia D; Bisesi, Michael S; Ames, April L; Khuder, Sadik; Susi, Pam; Akbar-Khanzadeh, Mahboubeh

    2010-12-01

    Concrete grinding exposes workers to unacceptable levels of crystalline silica dust, known to cause diseases such as silicosis and possibly lung cancer. This study examined the influence of major factors of exposure and effectiveness of existing dust control methods by simulating field concrete grinding in an enclosed workplace laboratory. Air was monitored during 201 concrete grinding sessions while using a variety of grinders, accessories, and existing dust control methods, including general ventilation (GV), local exhaust ventilation (LEV), and wet grinding. Task-specific geometric mean (GM) of respirable crystalline silica dust concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled-grinding, while GV was off/on, were 0.17/0.09, 0.57/0.13, 1.11/0.44, and 23.1/6.80, respectively. Silica dust concentrations (mg/m³ using 100-125 mm (4-5 inch) and 180 mm (7 inch) grinding cups were 0.53/0.22 and 2.43/0.56, respectively. GM concentrations of silica dust were significantly lower for (1) GV on (66.0%) vs. off, and (2) LEV:HEPA- (99.0%), LEV:Shop-vac- (98.1%) or wet- (94.4%) vs. uncontrolled-grinding. Task-specific GM of respirable suspended particulate matter (RSP) concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled grinding, while GV was off/on, were 1.58/0.63, 7.20/1.15, 9.52/4.13, and 152/47.8, respectively. GM concentrations of RSP using 100-125 mm and 180 mm grinding cups were 4.78/1.62 and 22.2/5.06, respectively. GM concentrations of RSP were significantly lower for (1) GV on (70.2%) vs. off, and (2) LEV:HEPA- (98.9%), LEV:Shop-vac- (96.9%) or wet- (92.6%) vs. uncontrolled grinding. Silica dust and RSP were not significantly affected by (1) orientation of grinding surfaces (vertical vs. inclined); (2) water flow rates for wet grinding; (3) length of task-specific sampling time; or, (4) among cup sizes of 100, 115 or 125 mm. No combination of factors or control methods reduced an 8-hr exposure level to below the

  15. Modeling and research of temperature distribution in surface layer of titanium alloy workpiece during AEDG and conventional grinding

    Science.gov (United States)

    Gołąbczak, M.; Gołąbczak, A.; Konstantynowicz, A.; Święcik, R.

    2016-11-01

    Titanium and its alloys are widely recognized as the hardly machinable materials, especially due to their relatively high hardness, low thermal conductivity and possible subcritical superplasticity. Then, a thorough control of the machining process parameters shall be maintained. In this paper, we have concentrated on the grinding of the Ti6Al4V titanium alloy using cBN (boron nitride) grinding wheel combined with the AEDG (abrasive electrodischarge grinding) process. The mathematical model we have dealt with has been based mainly on Jaeger model of the heat taking over between sliding bodies with substantial upgrades related to:estimation of the frictional heat generating based on friction forces distribution,

  16. ELID Mirror Grinding Technology——Development of Metal Bonded Grinding Wheel%ELID镜面磨削技术——金属结合剂砂轮的研制

    Institute of Scientific and Technical Information of China (English)

    关佳亮; 郭东明; 周曙光; 袁哲俊

    2001-01-01

    As the result of the study on the effects of copper powder and other relative metal additives used for ELID grinding wheel manufacturing, a new kind of grinding wheel is presented for ELID grinding and experimental results show that such a grinding wheel has its great advantage and can be used for production pur pose.%采用铜粉、还原铁粉、铸铁粉并辅以改善铁粉和铸铁粉末冶金性能的金属添加剂作配方,烧制出适合现有生产条件的ELID磨削用砂轮磨块。性能检验表明该配方满足了ELID磨削要求。

  17. Influência na qualidade final de metais retificados através da variação da velocidade de mergulho Variable feed-rate influence on the final quality of metal grinding

    Directory of Open Access Journals (Sweden)

    Manoel Cleber Sampaio Alves

    2009-03-01

    Full Text Available A retificação, processo final de usinagem de uma peça, utiliza fluidos de corte com a finalidade de lubrificação, refrigeração e remoção de cavacos. No entanto, esses fluidos são extremamente agressivos com o meio. Com o avanço tecnológico a tendência mundial é produzir peças cada vez mais sofisticadas, com elevado grau de tolerância geométrica, dimensional, com bom acabamento superficial, com baixo custo e, principalmente, sem causar danos ao meio. Para tanto, ao processo de retificação está intrínseca a reciclagem do fluido de corte, que se destaca pelo seu custo. Através da variação da velocidade de avanço no processo de retificação cilíndrica externa do aço ABNT D6, racionalizando a aplicação de dois fluidos de corte e usando um rebolo superabrasivo de CBN (nitreto de boro cúbico com ligante vitrificado, avaliaram-se os parâmetros de saída da força tangencial de corte, emissão acústica, rugosidade, circularidade, desgaste da ferramenta, tensão residual e a integridade superficial através da microscopia eletrônica de varredura (MEV dos corpos-de-prova. Com a análise do desempenho do fluido, do rebolo e da velocidade de mergulho, encontraram-se as melhores condições de usinagem propiciando a diminuição do volume de fluido de corte e a diminuição do tempo de usinagem, sem prejudicar os parâmetros geométricos e dimensionais, o acabamento superficial e a integridade superficial dos componentes.Grinding, the final stage of the machining process, employs a significant amount of cutting fluids for lubrication, cooling and swarf removal. However, these cutting fluids are extremely aggressive to the environment. With technological progress, the world tendency is to produce more and more sophisticated pieces,having a high degree of geometrical and dimensional tolerance, good surface finish, hlow cost and, mainly, insignificant impact on the environment. Therefore, recycling cutting fluids is intrinsic

  18. Grinding and polishing instead of sectioning for the tissue samples with a graft: Implications for light and electron microscopy.

    Science.gov (United States)

    Mukhamadiyarov, Rinat A; Sevostyanova, Victoria V; Shishkova, Daria K; Nokhrin, Andrey V; Sidorova, Olga D; Kutikhin, Anton G

    2016-06-01

    A broad use of the graft replacement requires a detailed investigation of the host-graft interaction, including both histological examination and electron microscopy. A high quality sectioning of the host tissue with a graft seems to be complicated; in addition, it is difficult to examine the same tissue area by both of the mentioned microscopy techniques. To solve these problems, we developed a new technique of epoxy resin embedding with the further grinding, polishing, and staining. Graft-containing tissues prepared by grinding and polishing preserved their structure; however, sectioning frequently required the explantation of the graft and led to tissue disintegration. Moreover, stained samples prepared by grinding and polishing may then be assessed by both light microscopy and backscattered scanning electron microscopy. Therefore, grinding and polishing outperform sectioning when applied to the tissues with a graft.

  19. Pre-etching vs. grinding in promotion of adhesion to intact enamel using self-etch adhesives.

    Science.gov (United States)

    Nazari, Amir; Shimada, Yasushi; Sadr, Alireza; Tagami, Junji

    2012-01-01

    This study was aimed to determine the effectiveness of grinding and pre-etching in promotion of adhesion to human intact enamel using the self-etch adhesive (SEA) Adper Easy Bond (3M ESPE). Etch-and-rinse adhesive Adper Single Bond (3M ESPE) served as control. Composite cylinders (AP-X Kuraray) were built and after 24 h micro-shear bond strengths (MSBS) were measured. Bonding interfaces were evaluated under scanning electron microscope (SEM). For evaluation of average roughness (Ra) and morphological analysis, treated enamel surfaces were observed under SEM and confocal laser scanning microscope (CLSM) with 3D surface profiling. Highest bond strengths were obtained by pre-etching and grinding showed a less significant role. Phosphoric acid (PA) etching compare to grinding created significantly rougher surface (Ra: 0.72 and 0.43 µm respectively). Therefore, this study recommends pre-etching the intact enamel prior to application of the adhesive instead of grinding.

  20. Condition monitoring on grinding wheel wear using wavelet analysis and decision tree C4.5 algorithm

    Directory of Open Access Journals (Sweden)

    S.Devendiran

    2013-10-01

    Full Text Available A new online grinding wheel wear monitoring approach to detect a worn out wheel, based on acoustic emission (AE signals processed by discrete wavelet transform and statistical feature extraction carried out using statistical features such as root mean square and standard deviation for each wavelet decomposition level and classified using tree based knowledge representation methodology decision tree C4.5 data mining techniques is proposed. The methodology was validate with AE signal data obtained in Aluminium oxide 99 A(38A grinding wheel which is used in three quarters of majority grinding operations under different grinding conditions to validate the proposed classification system. The results of this scheme with respect to classification accuracy were discussed.

  1. Synthesis and electrochemical preformances of tribasic and tetrabasic lead sulfates prepared by reactive grinding

    Science.gov (United States)

    Grugeon-Dewaele, S.; Laruelle, S.; Joliveau-Vallat, F.; Torcheux, L.; Delahaye-Vidal, A.

    Tribasic lead sulfate (3BS) and tetrabasic lead sulfate (4BS), used as precursors of the positive active material in the lead/acid batteries, were prepared by a new method: reactive grinding. The effects of various experimental parameters (stoichiometry, hygrometry of the starting compounds, duration of mechanical treatment) upon the nature and morphological features of the resulting phase were investigated. Among them, hygrometry turned out to be the most critical one. With water in excess, only 3BS was produced while dry reagents led to 4BS. In both cases, samples with a small particle size and high reactivity were obtained. In order to evaluate the influence of the morphology upon the electrochemical performances of such grinding produced samples, the capacity was measured and compared with that of traditional 3BS and 4BS samples.

  2. An investigation of the corrosive wear of steel balls in grinding of sulphide ores

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2015-06-01

    Full Text Available Ball mills are common grinding equipment in mineral processing industries. Ball wear results from three mechanisms namely impact, abrasion and corrosion. Of these, the corrosion mechanism is the least investigated, due to its chemical-electrochemical nature. Therefore, the aims of this research were to investigate the grinding chemistry influence (slurry pH, solid percentage, water chemistry and gas purging on corrosive wear of steel balls and to determine the contribution of corrosion mechanism to total wear of steel balls. The results indicated that the mass losses of steel balls could be reduced considerably by controlling the pulp chemistry inside the mill. In addition, the results showed that 73.51% of the corrosion products are generated from the oxidation of steel balls. It was also estimated that the corrosion mechanism accounts for 26.68% of the total wear of steel balls.

  3. Freeform surface grinding and polishing by CCOS based on industrial robot

    Science.gov (United States)

    Liu, HaiTao; Wan, YongJian; Zeng, ZhiGe; Xu, LiChao; Zhao, HongShen; Fang, Kai

    2016-10-01

    The grinding and polishing of freeform surface by using Computer Controlled Optical Surfacing (CCOS) technology are discussed. Instead of using Computer Numeric Control (CNC) machine, a 6-axises industrial robot TX200 from Stäubli Co. Ltd. is used as the motion platform. In order to perform the movement that CCOS technology needs, the coordinate system of the robot in processing is reviewed and the offline programming method for robot is presented. The material removal experiments during grinding and polishing process on the robotic CCOS platform are been carried out. A rectangular toroid surface workpiece and a circular off-axis parabolic surface workpiece are being fabricated on the robotic CCOS platform, and the latest results will be discussed here.

  4. The effect of bean origin and temperature on grinding roasted coffee

    Science.gov (United States)

    Uman, Erol; Colonna-Dashwood, Maxwell; Colonna-Dashwood, Lesley; Perger, Matthew; Klatt, Christian; Leighton, Stephen; Miller, Brian; Butler, Keith T.; Melot, Brent C.; Speirs, Rory W.; Hendon, Christopher H.

    2016-04-01

    Coffee is prepared by the extraction of a complex array of organic molecules from the roasted bean, which has been ground into fine particulates. The extraction depends on temperature, water chemistry and also the accessible surface area of the coffee. Here we investigate whether variations in the production processes of single origin coffee beans affects the particle size distribution upon grinding. We find that the particle size distribution is independent of the bean origin and processing method. Furthermore, we elucidate the influence of bean temperature on particle size distribution, concluding that grinding cold results in a narrower particle size distribution, and reduced mean particle size. We anticipate these results will influence the production of coffee industrially, as well as contribute to how we store and use coffee daily.

  5. MECHANICAL DISINTEGRATION OF WHEAT STRAW BY ROLLER-PLATE GRIND SYSTEM WITH SHARP-EDGED SEGMENTS

    Directory of Open Access Journals (Sweden)

    Lukas Kratky

    2015-04-01

    Full Text Available Colloid mills and extruders are widely used for disintegrating wet fibrous biomass. However, their main disadvantages are a high energy requirement in the range of hundreds or thousands of kWh per ton of material, and the fact that they grind in process cycles. Efforts have therefore been made to design a new type of continuously operated grinder. Its disintegration principle uses a roller-plate grinding system with sharp-edged segments, where the compressive and shear forces combine to comminute the particles. Test experiments verified that the grinder disintegrates wet untreated straw to particles below 10mm in an effective manner in a single pass, with an energy requirement of 50 kWht−1 TS. A 23% increase in biogas yield was achieved, leading to a net gain in electric energy of310 kWht−1 TS.

  6. High Efficiency Axial Deep Creep-Feed Grinding Machining Technology of Engineering Ceramics Materials

    Institute of Scientific and Technical Information of China (English)

    GUO Fang; ZHANG Baoguo; LU Hong; TIAN Xinli; WANG Jianquan; LI Fuqiang

    2012-01-01

    Axial deep creep-feed grinding machining technology is a high efficiency process method of engineering ceramics materials,which is an original method to process the cylindrical ceramics materials or hole along its axis.The analysis of axial force and edge fracture proved the cutting thickness and feed rate could be more than 5-10 mm and 200 mm/min respectively in once process,and realized high efficiency,low-cost process of engineering ceramics materials.Compared with high speed-deep grinding machining,this method is also a high efficiency machining technology of engineering ceramics materials as well as with low cost.In addition,removal mechanism analyses showed that both median/radial cracks and lateral cracks appeared in the part to be removed,and the processed part is seldom destroyed,only by adjusting the axial force to control the length of transverse cracks.

  7. Application of multi regressive linear model and neural network for wear prediction of grinding mill liners

    Directory of Open Access Journals (Sweden)

    Farzaneh Ahmadzadeh

    2013-06-01

    Full Text Available The liner of an ore grinding mill is a critical component in the grinding process, necessary for both high metal recovery and shell protection. From an economic point of view, it is important to keep mill liners in operation as long as possible, minimising the downtime for maintenance or repair. Therefore, predicting their wear is crucial. This paper tests different methods of predicting wear in the context of remaining height and remaining life of the liners. The key concern is to make decisions on replacement and maintenance without stopping the mill for extra inspection as this leads to financial savings. The paper applies linear multiple regression and artificial neural networks (ANN techniques to determine the most suitable methodology for predicting wear. The advantages of the ANN model over the traditional approach of multiple regression analysis include its high accuracy.

  8. A mathematical model for surface roughness of fluidic channels produced by grinding aided electrochemical discharge machining (G-ECDM)

    OpenAIRE

    Ladeesh V. G.; Manu R

    2017-01-01

    Grinding aided electrochemical discharge machining is a hybrid technique, which combines the grinding action of an abrasive tool and thermal effects of electrochemical discharges to remove material from the workpiece for producing complex contours. The present study focuses on developing fluidic channels on borosilicate glass using G-ECDM and attempts to develop a mathematical model for surface roughness of the machined channel. Preliminary experiments are conducted to study the effect of mac...

  9. The Tucker technique: the proximal hollow grind to address a root concavity.

    Science.gov (United States)

    Hess, T A

    2014-01-01

    Cast gold inlays have long been used to conservatively restore compromised tooth structure. When the mesial or distal proximal surfaces are indicated for restoration and a cast gold restoration is desired, traditionally a box is prepared with an external bevel. Often a root concavity does not allow for a standard box form or the external and/or internal bevels. A proximal hollow grind can be utilized to address limits of standard inlay or onlay preparation design.

  10. 移动磨削装置的设计%The Design of Mobile Grinding Device

    Institute of Scientific and Technical Information of China (English)

    张占福; 赵志

    2014-01-01

    移动磨削装置的设计,主要是利用普通机床设备,通过增加自行设计开发的移动式卧车磨削装置,将其装夹在卧式车床的刀架上,作为磨削工具,使其达到以车代磨的目的,实现对矿浆输送隔膜泵设备中各种不同规格隔膜室的远距离、高磨蚀加工。该移动式卧车磨削隔膜室装置具有效率高、运行可靠和制造成本低等诸多优点,有利于节约能源和环境保护,市场前景非常广阔,现广泛应用于公司各种国内大型隔膜腔及内孔圆弧加工。%The design of moving grinding equipment is made by adding moving lie -grinding device to the-machine tool facility .The device is loaded on knife rest of lie -grindiing . As a grinding tool ,this gringding equipment can machine the septum -ventricle of the mine -feeding septum -equipment in long distance and hight ablation .This make turning machining displace grinding machining .The equipment has some merit as hight -efficiency ,good credibility and lower cost . In favor of saving energy and protecting envi-ronment ,this equipment has very great foreground in market and had been used in machining the septum -ventricle and the arc of in hole at our company .

  11. DESIGN OF INTELLIGENT CONTROL SYSTEM USING ACOUSTIC PARAMETERS FOR GRINDING MILL OPERATION

    Directory of Open Access Journals (Sweden)

    Sonali Sen

    2013-02-01

    Full Text Available This paper utilizes acoustic parameters such as FS,NC, N, P, INC, FL, FH, W for acoustic signals S of different running conditions of a ballmill to deriveout the acoustic signatures and hence control signals, which is to be used for designing the control systems of the mill. The parameters FS, NC, N, P, INC, FL, FH and W are represented by sample rate in Hz, number of cepstral coefficients, length of frame in samples, number of filters in filter bank, frame increment, low end of the lowest filter, high end of highest filter and the window over which the analysis is to be performed respectively. The work establishes an appropriate theoretical background that helps to predict dynamic breakage characteristics with respect to particle size distribution of materials, adequately supported by experimental data. The signatures of different running conditions of grinding mill have been extracted from the captured signal in time frame these have been used as feedback signal to monitor the grinding operation. Condenser based microphones have been used for capturing acoustic signals in time domain directly in computers and stored for further analysis. Matlab R2010b has been used for different analysis of the experiment. On analyzing the signatures, it has been observed whether the fines are produced progressively to attain the desired size range or the mill producing undesired products. Thus, the approach has been used in this paper has the ability to arrive in the stage of optimum grinding by tuning parameters of the mill in real time, and also it can prevent the mill to enter into an erroneous state. Moreover, on study it has found that the present scheme can be used more accurately in comparison to the earlier work of the author. This paper presents an implementation scheme to use acoustic signal as the control signal to regulate the operation of a grinding mill.

  12. Performance of an electrochemical COD (chemical oxygen demand) sensor with an electrode-surface grinding unit.

    Science.gov (United States)

    Geun Jeong, Bong; Min Yoon, Seok; Ho Choi, Chang; Koang Kwon, Kil; Sik Hyun, Moon; Heui Yi, Dong; Soo Park, Hyung; Kim, Mia; Joo Kim, Hyung

    2007-12-01

    An electrochemical COD (chemical oxygen demand) sensor using an electrode-surface grinding unit was investigated. The electrolyzing (oxidizing) action of copper on an organic species was used as the basis of the COD measuring sensor. Using a simple three-electrode cell and a surface grinding unit, the organic species is activated by the catalytic action of copper and oxidized at a working electrode, poised at a positive potential. When synthetic wastewater was fed into the system, the measured Coulombic yields were found to be dependent on the COD of the synthetic wastewater. A linear correlation between the Coulombic yields and the COD of the synthetic wastewater was established (10-1000 mg L(-1)) when the electrode-surface grinding procedure was activated briefly at 8 h intervals. When various kinds of wastewater samples obtained from various sewage treatment plants were measured, linear correlations (r(2)> or = 0.92) between the measured EOD (electrochemical oxygen demand) value and COD of the samples were observed. At a practical wastewater treatment plant, the measurement system was successfully operated with high accuracy and good stability over 3 months. These experimental results show that the application of the measurement system would be a rapid and practical method for the determination of COD in water industries.

  13. Experimental Study of Machinability in Mill-grinding of SiCp/Al Composites

    Institute of Scientific and Technical Information of China (English)

    LI Jianguang; DU Jinguang; YAO Yingxue; HAO Zhaopeng; LIU Xiao

    2014-01-01

    An attempt was made to investigate the machinability of SiCp/Al composites based on the experimental study using mill-grinding processing method. The experiments were carried out on a high-speed CNC machining center using integrated abrasive cutting tool. The effects of combined machining parameters, e g, cutting speed (vs), feed rate (vf), and depth of cut (ap), with the same change of material removal rate (MRR) on the mill-grinding force and surface roughness (Ra) were investigated. The formation mechanism of typical machined surface defects was analyzed by SEM. The experimental results reveal that with the same change of material removal rate, lower mill-grinding force values can be gained by increasing depth of cut and feed rate simultaneously at higher cutting speed. With the same change of MRR value, lower surface roughness values can be gained by increasing the feed rate at higher cutting speed, rather than just increasing the depth of cut, or increasing the feed rate and depth of cut simultaneously. The machined surface of SiCp/Al composites reveals typical defects which can influence surface integrity.

  14. Grinding Characteristic of Multi-walled Carbon Nanotubes-alumina Composite Particle

    Institute of Scientific and Technical Information of China (English)

    B MUNKHBAYAR; Nasan BAYARAA; Hafizur REHMAN; Junhyo KIM; Hanshik CHUNG; Hyomin JEONG

    2012-01-01

    The synthesis of new materials containing multi-walled carbon nanotubes (MWCNTs) and the microstructure of alumina particles were investigated and characterized.The MWCNTs and alumina particles were ground under both the dry and wet conditions with various rotation speeds (200-400 r/min) in planetary ball milling machine,and their combination characteristics were described.The experimental results were examined by scanning electron microscopy (SEM),X-ray diff action (XRD),transmission electron microscopy (TEM) and particle sizing analysis (PSA).SEM result revealed that the combination of MWCNTs -Alumina particles mixed quite well under both the dry and wet grinding with rotation speed of 400 r/min.XRD characterization indicated the better result could get in ground samples at a rotation speed of 400 r/min.PSA result showed the particle size decreased with increase the grinding speeds.From the overall results,we observed that the grinding method can be used to synthesize new material with high efficiency.

  15. DETERMINATION AND OPTIMIZATION OF CYLINDRICAL GRINDING PROCESS PARAMETERS USING TAGUCHI METHOD AND REGRESSION ANALYSIS

    Directory of Open Access Journals (Sweden)

    M.Janardhan

    2011-07-01

    Full Text Available Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operations. Metal removal rate and surface finish are the important out put responses in the production with respect to quantity and quality respectively. The Experiments are conducted on CNC cylindrical grinding machine with L9 Orthogonal array with input machining variables as work speed, feed rate and depth of cut. Empirical models are developed using design of experiments and response surface methodology. The adequacy of thedeveloped model is tested with ANNOVA. The developed model can be used by the different manufacturing firms to select right combination of machining parameters to achieve an optimal metal removal rate (MRR and surface roughness (Ra.The results reveals that feed rate, depth of cut are influences predominantly on the output responses metal removal rate (MRR and surface roughness (Ra.The predicted optimal values for MRR, Ra for Cylindrical grinding process are 62.05 gm/min and 0.816 μm respectively. The results are further confirmed by conducting confirmation experiments.

  16. Rapidly removing grinding damage layer on fused silica by inductively coupled plasma processing

    Science.gov (United States)

    Chen, Heng; Zhou, Lin; Xie, Xuhui; Shi, Baolu; Xiong, Haobin

    2016-10-01

    During the conventional optical shaping process of fused silica, lapping is generally used to remove grinding damage layer. But this process is of low efficiency, it cannot meet the demand of large aperture optical components. Therefore, Inductively Coupled Plasma Processing (ICPP) was proposed to remove grinding damage layer instead of lapping. ICPP is a non-contact, deterministic figuring technology performed at atmospheric pressure. The process benefits from its ability to simultaneously remove sub-surface damage (SSD) while imparting the desired figure to the surface with high material remove rate. The removing damage capability of ICPP has preliminarily been confirmed on medium size optical surfaces made of fused silica, meanwhile serious edge warping was found. This paper focused on edge effect and a technique has been designed to compensate for these difficulties. Then it was demonstrated on a large aperture fused silica mirror (Long320mm×Wide370mm×High50mm), the removal depth was 30.2μm and removal rate got 6.6mm3/min. The results indicate that ICPP can rapidly remove damage layer on the fused silica induced by the previous grinding process and edge effect is effective controlled.

  17. Wheel efficiency in the diamond-spark erosion grinding of tungsten carbides

    Science.gov (United States)

    Uzunjan, M. D.; Krasnoscek, J. S.

    1982-11-01

    Diamond-spark erosion grinding on metallic bond is a highly productive process used in working difficult materials. It is of considerable interest to investigate the efficiency of diamond wheels in the grinding of hard alloys while supplying impulse energy to the cutting zone. The efficiency of 150 x 10 x 3 ACK cup wheels made with ACB diamonds on MB1 bond as evaluated experimentally by the multifactor method using the following optimized parameters: removal rate Q (cu mm/min), specific diamond consumption q (mg/g) and a specific grinding cost C (kopecks/cu cm). A TI5K6 hard alloy sample 60 sq mm in cross section was ground using a 3B642 grinder with a 3% soda solution as coolant. The cutting zone was supplied with electrical impulse energy from an SGI 40-440 generator. The mean current ranged from 4 to 10 amps, the impulse frequency was 88 kHz, the degree of porosity was 2, the anode was the diamond wheel and the cathode was the treated material.

  18. Systematic Geometric Error Modeling for Workspace Volumetric Calibration of a 5-axis Turbine Blade Grinding Machine

    Institute of Scientific and Technical Information of China (English)

    Abdul Wahid Khan; Chen Wuyi

    2010-01-01

    A systematic geometric model has been presented for calibration of a newly designed 5-axis turbine blade grinding machine.This machine is designed to serve a specific purpose to attain high accuracy and high efficiency grinding of turbine blades by eliminating the hand grinding process.Although its topology is RPPPR (P:prismatic;R:rotary),its design is quite distinct from the competitive machine tools.As error quantification is the only way to investigate,maintain and improve its accuracy,calibration is recommended for its performance assessment and acceptance testing.Systematic geometric error modeling technique is implemented and 52 position dependent and position independent errors are identified while considering the machine as five rigid bodies by eliminating the set-up errors ofworkpiece and cutting tool.39 of them are found to have influential errors and are accommodated for finding the resultant effect between the cutting tool and the workpiece in workspace volume.Rigid body kinematics techniques and homogenous transformation matrices are used for error synthesis.

  19. Mathematical models of grinding manufacture and tooth contact analysis of spherical gears

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The spherical gear is a gear-driven mechanism with two degrees of freedom (DOF), which can transfer spatial motion and power. Grinding machining of the spherical gear is performed with a plate grinding wheel by using generating method, and based on mathematical model of the plate grinding wheel, the mathematical model of the spherical gear is set up. And then, the meshing model of a spherical gear pair is developed and the tooth contact analysis (TCA) of the spherical gear pairs is performed. After that, the position of a contact point on teeth surfaces of the spherical gear pair can be solved by using a nonlinear solver. Finally, the paths of contact points on teeth surfaces of the spherical gear are studied: Since every tooth of the spherical gear is diverse, the contact paths of the meshing of the spherical gear pair are complex and multiform. These are very useful to further investigations on transmission theory and practical applications of spherical gear pairs.

  20. Influence of suspension stability on wet grinding for production of mineral nanoparticles

    Institute of Scientific and Technical Information of China (English)

    S. Sakthivel; Venkatesan V. Krishnan; Pitchumani

    2008-01-01

    Grinding behavior of nanoparticles in an attritor mill and the minimum achievable particle size are strongly influenced by the suspension stability. In the present work, suspension stability (i.e. (-potential) of nanoparticles was studied by measuring pH as a function of grinding time in the wet milling process. It was found that after a certain time in an attritor mill, there is no further size reduction and the average product particle size increases monotonically. One of the reasons is that the production of submicron particles leads to more particle-particle interactions and consequently pH of the suspension decreases with grinding time. Usually pH value is related to suspension stability and it can be enhanced by addition of NaOH solution. The maximum negative (-potential of -51.2 mV was obtained at pH of 12 for silica. The higher the (-potential with the same polarity, higher will be the electrostatic repulsion between the particles. Hence, the maximum electrostatic repulsion force was maintained by the adjustment of pH value in wet milling. The experiments were conducted at different pH conditions which were maintained constant throughout the experiments and nanosized particles were obtained consequently.

  1. Application of Ultra-Small Micro Grinding and Micro Milling Tools: Possibilities and Limitations

    Directory of Open Access Journals (Sweden)

    Benjamin Kirsch

    2017-08-01

    Full Text Available Current demands for flexible, individual microstructures in high quality result in high requirements for micro tools. As the tool size defines the minimum structure size, ultra-small tools are needed. To achieve tool diameters of 50 µm and lower, we investigate the complete manufacturing chain of micro machining. From the development of the machine tools and components needed to produce and apply the micro tools, the micro tools themselves, as well as the micro machining processes. Machine tools are developed with the possibility of producing the micro geometry (cutting edge design of micro tools as well as plating processes to produce super abrasive micro grinding tools. Applying these setups, we are able to produce ultra-small micro grinding and micro milling tools with typical diameters of 50 µm and down to 4 µm. However, the application of such tools is very challenging. The article presents possibilities and limitations in manufacturing the micro tools themselves as well as microstructures made with these tools. A special emphasis will be on the influence of the tool substrate in micro milling and grain sizes in micro grinding.

  2. Study of pulmonary (lung) functioning of commercial wheat grinding machine operators in India using spirometric testing.

    Science.gov (United States)

    Agashe, Abhijeet; Deshpande, V S

    2010-04-01

    In ancient times, in India each household had a chakki to mill the wheat. There was no concept of getting wheat grounded from outside. With the fast changing lifestyle, this tradition has almost disappeared now. Today every city of India has numerous commercial wheat grinding machine shops located at various places. Other than states like Punjab, this occupation is mostly unorganized and little has been done to look into the welfare and health of these machine operators. Like most of the occupations, this occupation of wheat grinding also has several occupational hazards and injuries associated with it. The most obvious of them all in this case is due to the continuous exposure of the operators to the rising dust wheat particles, commonly called atta). This perpetual inhaling ofpollutants exposes the operators to risks of pulmonary malfunctioning. Therefore, this paper attempts to determine the pulmonary functioning of the commercial wheat grinding machine operators in India using spirometric testing. On the basis of the anthropometric data, effort has been done to develop the expected lung performance. Further, the actual lung performance of the operators is measured and compared with expected performance.

  3. A Hybrid Multiobjective Differential Evolution Algorithm and Its Application to the Optimization of Grinding and Classification

    Directory of Open Access Journals (Sweden)

    Yalin Wang

    2013-01-01

    Full Text Available The grinding-classification is the prerequisite process for full recovery of the nonrenewable minerals with both production quality and quantity objectives concerned. Its natural formulation is a constrained multiobjective optimization problem of complex expression since the process is composed of one grinding machine and two classification machines. In this paper, a hybrid differential evolution (DE algorithm with multi-population is proposed. Some infeasible solutions with better performance are allowed to be saved, and they participate randomly in the evolution. In order to exploit the meaningful infeasible solutions, a functionally partitioned multi-population mechanism is designed to find an optimal solution from all possible directions. Meanwhile, a simplex method for local search is inserted into the evolution process to enhance the searching strategy in the optimization process. Simulation results from the test of some benchmark problems indicate that the proposed algorithm tends to converge quickly and effectively to the Pareto frontier with better distribution. Finally, the proposed algorithm is applied to solve a multiobjective optimization model of a grinding and classification process. Based on the technique for order performance by similarity to ideal solution (TOPSIS, the satisfactory solution is obtained by using a decision-making method for multiple attributes.

  4. Behavior of surface integrity in cylindrical plunge grinding using different cooling systems

    Directory of Open Access Journals (Sweden)

    Leonardo Roberto Silva

    2011-01-01

    Full Text Available The superficial texture of the material can exert a decisive influence on the application and performance of the machined component. The conventional fluids used in grinding processes are environmental risk and can also be dangerous to the health. The disposal of these toxic fluids is expensive and the contamination in the proximities of the machines can present risks to the health for the personnel in the shop floor. This paper analyzes the performance of the minimum quantity lubricant (MQL technique and compares it with the conventional cooling method, developing an optimized fluid application method using a specially designed nozzle, through which a minimum amount of oil is sprayed in a compressed air flow. This paper also explores and discusses the concept of the MQL in the grinding process of hardened AISI 4340 steel. The performance of the MQL technique in grinding was evaluated based on an analysis of the surface integrity (roughness, microstructure and microhardness. As a result, it was realized that the MQL technique provides very similar characteristics to conventional process and can be applied in industry, thus contributing to an environment friendly manufacturing.

  5. Electrolytic In-process Dressing (ELID) for high-efficiency, precision grinding of ceramic parts: An experiment study

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, B.P.

    1995-08-01

    This report describes Electrolytic In-process Dressing (ELID) as applied to the efficient, high-precision grinding of structural ceramics, and describes work performed jointly by Dr. B.P. Bandyopadhyay, University of North Dakota, and Dr. R. Ohmori, of the Institute of Physical and Chemical Research (RINEN), Tokyo, Japan, from June through August, 1994. Dr. Ohmori pioneered the novel ELID grinding technology which incorporates electrolytically enhanced, in-process dressing of metal bonded superabrasive wheels. The principle of ELID grinding technology is discussed in the report as will its application for rough grinding and precision grinding. Two types of silicon nitride based ceramics (Kyocerals Si{sub 3}N{sub 4}, and Eaton`s SRBSN) were ground under various conditions with ELID methods. Mirror surface finishes were obtained with {number_sign} 4000 mesh size wheel (average grain size = 4 {mu}m). Results of these investigations are presented in this report. These include the effects of wheel bond type, type of power supply, abrasive grit friability, and cooling fluid composition. The effects of various parameters are discussed in terms of the mechanisms of ELID grinding, and in particular, the manner of boundary layer formation on the wheels and abrasive grit protrusion.

  6. 强冷磨削——一种控制表面残余应力的有效方法%Compulsive-cold Grinding—A Effective Method on Controlling Residual Stress

    Institute of Scientific and Technical Information of China (English)

    徐进; 陈秉均

    2001-01-01

    The usual grinding method usually brings about the extensive residual stress in the machined surface of part.Aimed at this phenomenon,experimented on compulsive-cold grinding.The test states,the compulsive-cold grinding can be used for controlling of the residual stress,it is a practicably effective method.%常规磨削通常使工件已加工表面产生残余拉应力,针对这一现象,进行了强冷磨削试验。试验结果证实,强冷磨削能实现对工件表面残余应力的主动控制,是一种切实可行的有效方法。

  7. 热管砂轮干磨削温度场数值模拟%Numerical simulation study on temperature field in dry grinding with heat pipe grinding wheel

    Institute of Scientific and Technical Information of China (English)

    梁星慧; 傅玉灿; 赫青山; 陈琛

    2012-01-01

    基于一种利用热管技术对磨削弧区进行强化换热的构想,采用FLUENT软件建立了环形热管砂轮干磨削温度场的仿真模型,得到了热管换热能力与热流密度、转速和砂轮壁厚的关系,并在相同热流密度下对比了热管砂轮与热管砂轮弧区的温度.仿真结果表明:弧区温度会随着热流密度的增大相应升高,随着转速的增大而降低,热管的启动时间会随着砂轮壁厚的增大减慢;相同热流密度下,热管砂轮的弧区温度明显低于无热管砂轮.最后通过干磨削钛合金TC4试验,对仿真结果进行了验证.%Based on the heat pipe technology to exchange heat, the heat transfer model of heat pipe grinding wheel (HPGW) using Fluent software was established. The influence of heat flux, thickness and rotation speed on the heat exchange capability in grinding zone with HPGW was analyzed in dry grinding process. The grinding temperature of HPGW was also compared with the grinding wheel without heat pipe in the same heat flux. The results showed that the grinding temperature of HPGW went up with the rising heat flux, decreased with the rising rotation speed, and the start lime of heat pipe got longer when the thickness increased. Furthermore, the grinding temperature of HPGW was much lower than the grinding wheel without heat pipe. In the end, the HPGW and the grinding wheel without heat pipe were respectively used lo conduct dry grinding. The experiment results proved the simulation results.

  8. Experimental Analysis of Residual Stresses in Samples of Austenitic Stainless Steel Welded on Martensitic Stainless Steel Used for Kaplan Blades Repairs

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2011-01-01

    Full Text Available Residual stresses occur in materials as a result of mechanical processes: welding, machining, grinding etc. If residual stresses reach high values they can accelerate the occurrence of cracks and erosion of material. An experimental research was made in order to study the occurrence of residual stresses in the repaired areas of hydraulic turbine components damaged by cavitation erosion. An austenitic stainless steel was welded in various layer thicknesses on a martensitic stainless steel base. The residual stresses were determined using the hole drilling strain gage method.

  9. Investigation of Creep Feed Grinding Parameters and Heat treatment Effects on the Nickel-base Superalloys

    Institute of Scientific and Technical Information of China (English)

    Hasan Jamshidi; Sayed Ali Sadough Vanini; Alireza Attari

    2004-01-01

    The Nickel base Superalloys are the most famous complicated and useable of Superalloys to make hot zone components of the gas turbines. The complicated dimensional tolerances, specially at the root of the blade show importance of grinding processes at the production of blades root. The prediction of the effect of machining parameters on the soundness of component surface strengthening for reaching to a suitable surface finishing and avoiding from crack formation at the work part during machining operation often is not easy and feasible so needs to more industrial investigation.This research is about frame 5 blade designed by GE and made from Superalloy IN738LC has been investigated. The formation of a plastically deformed and heat affected zone during grinding of Superalloy IN738LC with a high depth of cut but slow work speed (creep feed grinding) was investigated. Parameters such as work speed, depth of cut and radial dressing speed have been considered as variables and their effects have been studied. During experimental performed, the voltage and current of motor measured and power and special energy calculated.Some samples heat-treated (of the 1176℃ for 1 hr under neutral argon gas and cooling rate of 15℃/min up to 537℃ and then air cooling) to study grains recrystallization. Other samples have been created from the roots of blades and then coated by Nickel to measure boundary layer micro-hardness. The results show that increasing work speed leads to increasing the use power. Increasing the depth of cut, by increasing material removal rate, and the radial dressing speed, by decreasing power, lead to decreasing special energy. The temperature created by grinding lead to decreasing plastic deformation and boundary layer formation. When the radial dressing speed changes from 1 to 0.6 μm/rev and other parameters are kept unchanged the roughness of surface increases and the special energy decreases. Sufficient dressing is very essential in limiting the width

  10. The development of electrolyte grinding fluid on grinding with electrolyte in-process dressing%在线电解修整磨削的电解磨削液研制

    Institute of Scientific and Technical Information of China (English)

    朴承镐; 乔宏; 李杰; 李建军

    2001-01-01

    为了对金属结合剂砂轮电解修整,研究并配制了电解磨削液。根据电解磨削液的性能要求, 分析确定了电解磨削液中具有电解、钝化、防锈和润滑等性能的各组元,并通过静态实验确认了各组元对电解磨削液性能的影响。确定最佳电解磨削液在实际系统中对金属结合剂砂轮进行电解修整得到了较为满意的修整结果。所研制的电解磨削液具有实用价值,可用于生产。%In order to electrolyze dressing grinding wheel of metal binding agent, the elec trolytic grinding fluid is developed. According to the requirements of the elec trolytic grinding fluid, each constituent with properties such as the el ectrolysis, the inactivation, the rust prevention and the lubrication are analyz ed and determined and their effects to the electrolytic grinding fluid is obtain ed through the static experiments. In the actual system, the grinding wheel of metal binding agent is electrolytically dressed with the determined optimum elec trolytic grinding fluid and the satisfied dressing result is obtained. So the d eveloped electrolytic grinding fluid possesses the practical value which can be used in the manufacturing.

  11. Development of a mini-tablet of co-grinded prednisone-Neusilin complex for pediatric use.

    Science.gov (United States)

    Lou, H; Liu, M; Wang, L; Mishra, S R; Qu, W; Johnson, J; Brunson, E; Almoazen, H

    2013-09-01

    The purpose of this study is to enhance the dissolution rate of prednisone by co-grinding with Neusilin to form a complex that can be incorporated into a mini-tablet formulation for pediatrics. Prednisone-Neusilin complex was co-grinded at various ratios (1:1, 1:3, 1:5, and 1:7). The physicochemical properties of the complex were characterized by various analytical techniques including: differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), scanning electron microscope (SEM), particle size, surface area, solubility, and dissolution rate. The co-grinded prednisone-Neusilin complex (1:7) was blended with other excipients and was formulated into a 2-mm diameter mini-tablet. The mini-tablets were further evaluated for thickness, weight, content uniformity, and dissolution rate. To improve taste masking and stability, mini-tablets were coated by dip coating with Eudragit® EPO solution. DSC and XRPD results showed that prednisone was transformed from crystalline state into amorphous state after co-grinding with Neusilin. Particle size, surface area, and SEM results confirmed that prednisone was adsorbed to Neusilin's surface. Co-grinded prednisone-Neusilin complex (1:7) had a solubility of 0.24 mg/mL and 90% dissolved within 20 min as compared to crystalline prednisone which had a solubility of 0.117 mg/mL and 30% dissolved within 20 min. The mini-tablets containing co-grinded prednisone-Neusilin complex (1:7) exhibited acceptable physicochemical and mechanical properties including dissolution rate enhancement. These mini-tablets were successfully dip coated in Eudragit® EPO solution to mask the taste of the drug during swallowing. This work illustrates the potential use of co-grinded prednisone-Neusilin to enhance solubility and dissolution rate as well as incorporation into a mini-tablet formulation for pediatric use.

  12. SiCp/Al复合材料磨削力实验分析%Experiment analysis on grinding force of SiCp/Al

    Institute of Scientific and Technical Information of China (English)

    石莉; 周丽; 许立福; 黄树涛

    2011-01-01

    SiCp/Al composite material was grinded with diamond wheel on high - precision machine. Acquiring grinding force signals of the experiment with high speed advantech PCI-1712 board. Acquired grinding force signals are analyzed in MATLAB which has mighty function disposing signals. Through analyzing the grinding force in time field and the signals wavelet analysis for different grinding parameters, found that the feed velocity has much more influence on the grinding force, the grinding force ratio and the standard deviation of the grinding force than the depth of grinding when the velocity of the diamond wheel is fixed. The result of the experiment indicates that the grinding force increases and the grinding force ratio decreases with the increasing of feed velocity and grinding depth.%在高精密平面磨床上,使用金刚石砂轮磨削SiCp/Al复合材料,通过PCI-1712高速数据采集卡采集实验数据.在Matlab软件里,通过对不同磨削参数下的信号进行时域和小波分析,得出在砂轮速度一定时,进给速度对磨削力和磨削力比的影响最大,磨削深度次之,实验结果表明:随着进给速度和磨削深度的增大、磨削力增大,磨削力比减小.

  13. 内锥面刃磨机实现麻花钻螺旋面刃磨的研究与仿真%Research and simulation to realize helicoid grinding of twist drill with inner cone grinding machine

    Institute of Scientific and Technical Information of China (English)

    戴俊平; 郭辉; 关文魁; 卜睿

    2012-01-01

    According to the working principle of inner cone grinding machine, the differential of plate units is increased to replace the traditional variable lead.And two step motors are applied to drive respectively ball screw spindle and nut relative rotation and synthetize any thread pitch.Thus the method to achieve adjustable lead helicoid grinding is put forward as well as the method for grinding the helicoid within inner cone grinding machine,and then the formula of relief angle and oblique of chisel edge after grinding is derived.The author designs a virtual prototype of inner cone grinding machine with the Pro/E Software to realize helicoid grinding by motion simulation in its mechanism,which results verify that the mechanism after improving can realize the helicoid grinding.The mechanism is conducive to the realization of digital control of mechanical grinding.%根据内锥面刃磨机的工作原理,增加双层拖板的差动来代替传统的变导程,利用两步进电机分别带动丝杠主轴与螺母相对转动,合成任意螺距.实现导程可调的新螺旋面刃磨的方法,由此实现了在内锥面刃磨机中进行螺旋面刃磨的方法,并推导了刃磨后后角与横刃斜角的公式.然后基于Pro/E软件设计了机构的虚拟样机,并以双层拖板的分析为例对机构实现螺旋面刃磨而进行运动仿真,结果验证了改进后的机构可以实现螺旋面刃磨.此机构有利于实现数字化控制的机械刃磨.

  14. Feed Technology of Fibrous Sugarcane Residues for Ruminants

    Directory of Open Access Journals (Sweden)

    Kuswandi

    2007-06-01

    Full Text Available Abundant sugarcane residue during shortage of roughage in dry season gives an opportunity to raise ruminants around sugarcane industries. However, these products are not widely used by farmers due to an assumption that the usage is inefficient and that the feed utilization technology is not widely recognized. Sugarcane fibrous residues (tops, bagasse and pith may be a potential feed component if pre-treated to increase its digestion and consumption by the animal, and/or supplemented by other ingredients to balance nutrients in the rumen as well as those for production purpose. Digestibility can be increased by chemical treatments such as ammoniation and other alkaline treatments, whereas consumption can be increased by physical treatments such as grinding, hammermilling or pelleting. Nutrients that are missing in these fibrous residues can be provided by addition of urea, molasses and minerals for maintenance need, and bypass nutrients (carbohydrates, protein and fats that are digested in the small intestine and available for tissue or milk synthesis. There are three options for development of livestock agribusiness based on fibrous sugarcane residues; however, these require several technologies to optimize the utilization of these residues.

  15. Effect of grinding and heat treatment on the mechanical behavior of zirconia ceramic.

    Science.gov (United States)

    Ramos, Gabriela Freitas; Pereira, Gabriel Kalil Rocha; Amaral, Marina; Valandro, Luiz Felipe; Bottino, Marco Antonio

    2016-01-01

    The present study investigated the effect of grinding on roughness, flexural strength, and reliability of a zirconia ceramic before and after heat treatment. Seven groups were tested (n = 15): a control group (labeled CG, untreated), and six groups of samples ground with diamond discs, simulating diamond burs, with grits of 200 µm (G80); 160 µm (G120), and 25 µm (G600), either untreated or heat-treated at 1200°C for 2 h (labeled A). Yttria tetragonal zirconia polycrystal discs were manufactured, ground, and submitted to roughness and crystalline phase analyses before the biaxial flexural strength test. There was no correlation between roughness (Ra and Rz) and flexural strength. The reliability of the materials was not affected by grinding or heat treatment, but the characteristic strength was higher after abrasion with diamond discs, irrespective of grit size. The X-ray diffraction data showed that grinding leads to a higher monoclinic (m) phase content, whereas heat treatment produces reverse transformation, leading to a fraction of m-phase in ground samples similar to that observed in the control group. However, after heat treatment, only the G80A samples presented strength similar to that of the control group, while the other groups showed higher strength values. When zirconia pieces must be adjusted for clinical use, a smoother surface can be obtained by employing finer-grit diamond burs. Moreover, when the amount of monoclinic phase is related to the degradation of zirconia, the laboratory heat treatment of ground pieces is indicated for the reverse transformation of zirconia crystals.

  16. A Grinding Apparatus For Making A Middle-Size Parabolic Mirror Using The Link Mechanism Method

    Science.gov (United States)

    Shishido, Kora; Sugiura, Masao

    1987-01-01

    A large solar furnace that has a parabolic mirror with a diameter of 10m, a focal length of 3.2m and a heliostat mirror with an area of 15x15m was made by the authors at T6hoku University in 1962, and subsequently a small solar furnace having a parabolic mirror with a diameter of 1.5m, a focal -length of 0.5m and a heliostat mirror with an area of 2x2m was constructed at T6hoku Gakuin University in 1986. The large solar furnace could melt tungsten with a melting point of 3400°C, and the small solar furnace drove a stirling engine made in West Germany that had a rated power of 400W. The parabolic mirror of the segment type at TohokU University was made by a grinding apparatus that used a cam mechanism, and the parabolic mirror at T6hoku Gakuin University was made by an apparatus (hand-made by students)which employed a link mechanism to draw the parabolic curve. In this paper, the grinding apparatus used for making the segmental parabolic mirror with a diameter of 2-3m and a focal length of 0.5-1.0 m is reported. This mirror was used in a middle-size solar heat engine. The heat engine in this system was a Stirling engine with a rated power of 1-3KW, and the grinding apparatus (the precision parts moved in a linear track ) employed a compact link mechanism.

  17. Influence of laterotrusive occlusal scheme on bilateral masseter EMG activity during clenching and grinding.

    Science.gov (United States)

    Campillo, María José; Miralles, Rodolfo; Santander, Hugo; Valenzuela, Saúl; Fresno, María Javiera; Fuentes, Aler; Zúñiga, Claudia

    2008-10-01

    This study was designed to determine the effect of the occlusal scheme on masseter EMG activity at different jaw posture tasks. The sample included 30 healthy subjects with natural dentition and bilateral molar support, 15 with bilateral canine guidance, and 15 with bilateral group function. An inclusion criterion was that subjects had to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the left and right masseter muscles. EMG activity was recorded during the following jaw posture tasks: A. maximal clenching in the intercuspal position; B. grinding from intercuspal position to edge-to-edge lateral contact position; C. maximal clenching in the edge-to-edge lateral contact position; D. grinding from edge-to-edge lateral contact position to intercuspal position. EMG activity in tasks B, C, and D was lower than in task A (mixed model with unstructured covariance matrix). EMG activity was not significantly different with canine guidance or group function. EMG activity recorded on the nonworking side was higher than the working side during task C, and no different between tasks B or D. On the nonworking side, EMG activity in task B was significantly lower than C and D, and similar between task C and D. On the working side, EMG activity was significantly higher in task D than C and B, and in task B significantly higher than task C. The EMG patterns observed could be of clinical importance in the presence of parafunctional habits, i.e., clenching and/or grinding.

  18. Development and mechanical characterization of a polypropylene (pp) composite with grinding sludge as fiber

    Science.gov (United States)

    Rodrigues, D. A.; Oliveira, A. S. M.; Specht, R. F.; Santana, R. M. C.

    2014-05-01

    The search for alternative materials that provide reduced costs in manufacturing processes, and the need of to recycle materials normally disposable, it has aroused great interest and much research, with regard to reduction of material consumption due to its high cost and scarcity. Within this focus, this work aims to characterize a thermoplastic composite, whose polymer matrix is polypropylene (PP), and as disperse phase "grinding sludge, GS" from the various machining processes for grinding. After drying and sieving the GS and its subsequent mixing with the thermoplastic resin to prepare the PP/GS composites formulated were 80/20, 70/30, 60/40 w/w. The composite was injected into an injection mold in the form specimen test. The specimens followed the ASTM D638 and ASTM D256 for tensile and impact respectively. Three processing parameters were varied: the content of GS, temperature and injection rate. Each of these variables has three levels: L (low), M (medium) and H (high), making all possible combinations, totaling 27 processing conditions. The experimental conditions followed a statistical design obtained with the software Statgraphics Centurion, where the effects of variables are studied according to their statistical significance. An analysis of MEV and EDS was performed to obtain the characteristics of the "grinding sludge" (geometry and composition). Despite having been sifted, the geometry of the GS was still very rough, with varied shapes and sizes, and even made up a small percentage of abrasive grains. The variable that most influenced the mechanical properties was the content of particulate GS. The values obtained for the maximum tensile strength not behaved in descending order as expected, this may be the effect of small amount of samples tested. The results of the mechanical properties showed that for the elasticity modulus increased with increasing of GS; the values of elongation and impact strength decreased with increasing of GS.

  19. Technological Aspects of Forming the Surface Microrelief of Low-Wear Coatings after Electro-Diamond Grinding

    Science.gov (United States)

    Burov, V. G.; Yanpolskiy, V. V.; Rakhimyanov, K. Kh

    2016-04-01

    The results of electro-diamond grinding of coatings based on the WC25 powder material are presented in the paper. It is shown that after electro-diamond grinding of the WC25 coating, an obtained magnitude (Ra=2.02µm) of surface roughness doesn’t meet the qualifying standards to parts surface working in wear-out conditions. The forming of the obtained microrelief is probably connected to the features of electrochemical dissolution of the WC25 coating material in the electrolyte being used. Based on the polarization studies, it is revealed that the electrochemical dissolution character of the indicated coating in the water solution of 10%NaNO3 is determined by the dissolution character of cobalt (Co) component. The intensive cobalt (Co) dissolution during the electro-diamond grinding of the WC25 coating leads to the tungsten carbide chipping by the grinding disk particles that increases the roughness. One of the way to improve the surface quality of low-wear coatings after electro-diamond grinding is an introduction of an additional step in a technological process, carrying out with the switched off source of technological current. For realization of the process according to this scheme a technological dimension chain is made which takes into consideration the dissolution value of the most active coating composition element while the calculating of the operating dimensions of a detail.

  20. Effect of the corn breaking method on oil distribution between stillage phases of dry-grind corn ethanol production.

    Science.gov (United States)

    Wang, H; Wang, T; Johnson, L A; Pometto, A L

    2008-11-12

    The majority of fuel ethanol in the United States is produced by using the dry-grind corn ethanol process. The corn oil that is contained in the coproduct, distillers' dried grains with solubles (DDGS), can be recovered for use as a biodiesel feedstock. Oil removal will also improve the feed quality of DDGS. The most economical way to remove oil is considered to be at the centrifugation step for separating thin stillage (liquid) from coarse solids after distilling the ethanol. The more oil there is in the liquid, the more it can be recovered by centrifugation. Therefore, we studied the effects of corn preparation and grinding methods on oil distribution between liquid and solid phases. Grinding the corn to three different particle sizes, flaking, flaking and grinding, and flaking and extruding were used to break up the corn kernel before fermentation, and their effects on oil distribution between the liquid and solid phases were examined by simulating an industrial decanter centrifuge. Total oil contents were measured in the liquid and solids after centrifugation. Dry matter yield and oil partitioning in the thin stillage were highly positively correlated. Flaking slightly reduced bound fat. The flaked and then extruded corn meal released the highest amount of free oil, about 25% compared to 7% for the average of the other treatments. The freed oil from flaking, however, became nonextractable after the flaked corn was ground. Fine grinding alone had little effect on oil partitioning.

  1. Forest treatment residues for thermal energy compared with disposal by onsite burning: Emissions and energy return

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Greg; Calkin, David [Human Dimensions Science Program, Rocky Mountain Research Station, USDA Forest Service, PO Box 7669, 200 East Broadway Street, Missoula, MT 59807 (United States); Loeffler, Dan [The University of Montana, College of Forestry and Conservation, PO Box 7669, 200 East Broadway Street, Missoula, MT 59807 (United States); Chung, Woodam [The University of Montana, College of Forestry and Conservation, Missoula, MT 59812 (United States)

    2010-05-15

    Mill residues from forest industries are the source for most of the current wood-based energy in the US, approximately 2.1% of the nation's energy use in 2007. Forest residues from silvicultural treatments, which include limbs, tops, and small non-commercial trees removed for various forest management objectives, represent an additional source of woody biomass for energy. We spatially analyzed collecting, grinding, and hauling forest residue biomass on a 515,900 ha area in western Montana, US, to compare the total emissions of burning forest residues in a boiler for thermal energy with the alternatives of onsite disposal by pile-burning and using either natural gas or 2 distillate oil to produce the equivalent amount of useable energy. When compared to the pile-burn/fossil fuel alternatives, carbon dioxide emissions from the bioenergy alternative were approximately 60%, methane emissions were approximately 3%, and particulate emissions less than 10 {mu}m were 11% and 41%, respectively, for emission control and no-control boilers. Emissions from diesel consumption for collecting, grinding, and hauling biomass represented less than 5% of the total bioenergy emissions at an average haul distance of 136 km. Across the study area, an average 21 units of bioenergy were produced for each unit of diesel energy used to collect, grind, and haul biomass. Fossil fuel energy saved by the bioenergy alternative relative to the pile-burn/fossil fuel alternatives averaged 14.7-15.2 GJ t{sup -1} of biomass. (author)

  2. Practical Calculation of Thermal Deformation and Manufacture Error uin Surface Grinding

    Institute of Scientific and Technical Information of China (English)

    周里群; 李玉平

    2002-01-01

    The paper submits a method to calculate thermal deformation and manufacture error in surface grinding.The author established a simplified temperature field model.and derived the thermal deformaiton of the ground workpiece,It is found that there exists not only a upwarp thermal deformation,but also a parallel expansion thermal deformation.A upwarp thermal deformation causes a concave shape error on the profile of the workpiece,and a parallel expansion thermal deformation causes a dimension error in height.The calculations of examples are given and compared with presented experiment data.

  3. OpenGL Based Real Time&Inline Simulation of CNC Cams Grinding

    Directory of Open Access Journals (Sweden)

    Hu Zhanqi

    2013-06-01

    Full Text Available OpenGL based NC machining real time simulation model is proposed in the paper, and some key techniques of the system are investigated, including input and compiling of NC program, building of display model, real time displaying procedure of machining. With this technique, operator can view the machining process at screen of CNC machining real time, without stopping machine tool, which is very convenient for operating of machining. At last of the paper, an example of CNC cams grinding machine tool is given in order to proving the algorithm.

  4. Magnetic properties of amorphous Fe 78P 22 alloy obtained by mechanical grinding

    Science.gov (United States)

    Yelsukov, E. P.; Konygin, G. N.; Zagainov, A. V.; Barinov, V. A.

    1999-06-01

    The amorphous Fe 78P 22 alloy obtained by mechanical grinding was studied by X-ray analysis, Mössbauer spectroscopy and magnetic measurements. The measured values of the average hyperfine magnetic field H, mean magnetic moment per Fe atom mFe and Curie temperature Tc agree with those obtained earlier for electrodeposited and then ground samples and are in good qualitative agreement with the model describing macroscopic characteristics through the parameters of local environment but essentially disagree with the literature data for the samples obtained by rapidly quenching and only by electrochemical deposition.

  5. Technology of Rubber Cryogenic Grinding%橡胶低温粉碎技术综述

    Institute of Scientific and Technical Information of China (English)

    杜琳琳

    2012-01-01

    随着我国经济的发展和汽车工业的兴起,橡胶消耗量及废旧轮胎产量正逐年上升。我国每年70%以上的天然橡胶和40%以上的合成橡胶需依赖进口,回收废旧橡胶生产胶粉,既可以作为橡胶原料的补充,又可以缓解"黑色污染"引发的环境问题。介绍了废旧橡胶回收利用方式,提出低温粉碎法是生产精细胶粉的发展方向。通过对液氮冷冻粉碎法、空气冷冻粉碎法和LNG冷能低温粉碎法的比较,提出直接或间接利用LNG冷能低温粉碎生产胶粉,可以降低胶粉生产成本,带动废旧橡胶循环利用产业发展。%With the development of economic and the automobile industry in China,rubber consumption and waste tire production are increasing every year.In China,more than 70 % natural rubber and more than 40 % synthetic rubber need to rely on importing every year.Recycling of waste rubber and producing rubber powder can not only as a complement of rubber raw materials,but also alleviate the environmental problems caused by the "black pollution".It was introduced the way to recycle waste rubber,and indicated that freeze grinding was the developing direction in fine rubber powder production.By comparing freeze grinding in liquid nitrogen,air freeze grinding and LNG cold cryogenic,it was pointed that by direct or indirect using of LNG cold energy to produce rubber powder by cryogenic grinding,the powder production costs can be lower,and it can also drive waste rubber recycling industry development.

  6. Chemomechanical phenomena in the grinding of coal. Final report, February 1, 1976--May 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Macmillan, N.H.

    1977-08-01

    Vickers microhardness, drilling rate, grinding rate and zeta-potential measurements have been made on coals of various rank in both aqueous and organic environments in order to determine whether: (a) chemomechanical (Rebinder) effects exist in coal; and (b) any such effects as do exist can be used to improve the comminution of coal. The results reveal the mechanical behavior of coal to be remarkably environment-insensitive as compared to inorganic non-metals. As a result, it is concluded that chemomechanical phenomena offer little prospect of reducing the cost of comminuting coal.

  7. The Effect of Grinding and Polishing Procedure of Tool Steels in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Lindvall, F.; Bergström, J.; Krakhmalev, P.

    2010-01-01

    The surface finish of tools in sheet metal forming has a large influence on the performance of the forming tool. Galling, concern of wear in sheet metal forming, is a severe form of adhesive wear where sheet material is transferred on to the tool surface. By polishing the tools to a fine surface...... 40 and Vanadis 6 and up to ten different grinding and polishing treatments were tested against AISI 316 stainless steel. The tests showed that an optimum surface preparation might be found at the transition between abrasive and adhesive wear....

  8. Improved coal grinding and fuel flow control in thermal power plants

    DEFF Research Database (Denmark)

    Niemczyk, Piotr; Bendtsen, Jan Dimon

    2011-01-01

    A novel controller for coal circulation and pulverized coal flow in a coal mill is proposed. The design is based on optimal control theory for bilinear systems with additional integral action. The states are estimated from the grinding power consumption and the amount of coal accumulated...... in the mill by employing a special variant of a Luenberger observer. The controller uses the rotating classifier to improve the dynamical performance of the overall system. The proposed controller is compared with a PID-type controller with available pulverized coal flow measurements under nominal conditions...

  9. ALSTOM Schusselmuhle fur die feinvermahlung von anhydrit ALSTOM bowl mill for anhydrite fine grinding

    CERN Document Server

    Angleys, M

    2003-01-01

    After the ALSTOM bowl mill had proved a success during numerous laboratory tests using different industrial minerals, for the first time a mill, type SM 20/12 was commissioned for ATLAS s.c. at Lodz /Poland for anhydrite grinding. Based on corresponding laboratory tests with anhydrite, it was possible to adapt the equipment to the requirements of the material with modified properties. Due to the project preparation together with the customer, the mill could be installed and commissioned according to schedule by a joint team of engineers for erection and commissioning.

  10. Improving the Quality of Ceramic and Cemented Carbide Cutting Inserts by Diamond Grinding

    Directory of Open Access Journals (Sweden)

    Tareq Ahmad Abu Shreehah

    2005-01-01

    Full Text Available The machining of hardened steel and other difficult-to-cut materials require high quality and progressive cutting tools to meet the growing requirements for increasing productivity, improving tool life and quality of the cutting process. This study deals with an experimental investigation on the quality improvement by diamond grinding of ceramic and cemented carbide cutting inserts, comparing it with conventional batch produced types. It was found that under finish turning of hardened up to 61 HRC steel the ground cutting inserts improve the machined surface finish, reduce tool wear and breakage and subsequently extend the tool life.

  11. Micro Wire Electro Discharge Grinding: Optimization of Material Removal Rate and Surface Roughness

    Science.gov (United States)

    Yeakub Ali, Mohammad; Rahman, Mohamed Abd; Nordin, Rosmarina

    2017-03-01

    This paper presents the analysis and modelling of material removal rate (MRR) and surface roughness (Ra) by micro wire electro discharge grinding (micro-WEDG) with control parameter of gap voltage, feed rate, and spindle speed. The data were analyzed and empirical models are developed. The optimized values of MRR and Ra are 0.051 mm3/min and 0.25 μm respectively with 110 V gap voltage, 38 μm/s feed rate, and 1315 rpm spindle speed. The analysis showed that gap voltage has significant effect on material removal rate while spindle speed has significant effect on surface roughness.

  12. Apparatus for fixation of grinder shells upon a vibration-grinding casing

    Energy Technology Data Exchange (ETDEWEB)

    Pogosov, Yu.A.; Pugachev, V.S.

    1981-01-01

    A device is proposed for the fixation of grinder shells upon a vibration grinding table. This apparatus utilizes a table-mounting consisting of a shaft with a threaded head for a nut and lock-washer which is located in a mobile position below the locknut. Servicability is improved by utilizing radial-cantilevered protrusions in the mounting to facilitate end contact and fixation to the casing. The bushings and shaft are connected by pairs of threaded nuts while the bushings are spring-loaded relative to the table.

  13. Pulsed Laser Profiling of Grinding Wheels at Normal and Quasi-Tangential Incidence

    Science.gov (United States)

    Lutey, Adrian H. A.; Fortunato, Alessandro; Zanini, Filippo; Carmignato, Simone

    2016-09-01

    A new methodology for normal and quasi-tangential pulsed laser profiling of grinding wheels is proposed, with laser path planning calculated according to a pre-specified angle of incidence and radial laser progression or predicted single-pass incision depth. Though tangential laser profiling has previously been investigated, few works have addressed the issue of negligible laser absorption under these conditions other than to apply a focal offset that effectively reduces the angle of incidence below 90∘. In the present work, the angle of incidence is specified explicitly, with normal and quasi-tangential profiling experiments performed on rotating bronze-bonded diamond and porous aluminum oxide grinding wheels with a 1064 nm nanosecond pulsed fiber laser source with 20 W average power. Triangular incisions are cut into each sample, following which analyses are performed with an optical profiler operating in confocal mode and x-ray computed tomography to determine the material removal rate and profile accuracy under all tested conditions. The angle of laser incidence is found to be of particular relevance to profiling operations, with more than one order of magnitude difference in material removal rates observed between 70∘ and 80∘ incidence, with improved profile accuracy in the latter case. Specifically, material removal rates of 0.12-0.14 mm 3/ s, 0.075-0.1 mm 3/ s and 0.002 mm 3/ s are achieved at normal, 70∘ and 80∘ laser incidence, respectively, for bronze-bonded diamond, and 0.1 mm 3/ s is achieved at 70∘ incidence for porous aluminum oxide. For both materials, profile accuracy of 50-70 μm is achieved under optimum conditions. The presented results highlight the necessity for precise specification and control of the angle of incidence during laser profiling operations. They furthermore confirm that laser profiling of grinding wheels is a viable alternative to electrical discharge machining for bronze-bonded diamond grinding wheels and a potential

  14. Measurement of the air boundary layer on the periphery of a rotating grinding wheel using LDA

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H [AMTReL, GERI, Liverpool John Moores University, Liverpool (United Kingdom); Lin, B [School of Mechanical Engineering, Tianjin University, Tianjin (China); Cai, R [AMTReL, GERI, Liverpool John Moores University, Liverpool (United Kingdom); Morgan, M N [AMTReL, GERI, Liverpool John Moores University, Liverpool (United Kingdom)

    2007-07-15

    In this paper, the velocity profile of the air boundary layer around a rotating grinding wheel was measured using the Laser Doppler Anemometry technique. Experimental results show that the tangential velocity of the air decreases greatly with increasing distance from the wheel surface. The distribution of the tangential velocity is also found to be almost uniform near to the centre of the wheel width, and decreases greatly as the wheel edge is approached. Generally, the radial velocity of air in the area close to the wheel surface is small, and then increases with the increasing distance from wheel surface.

  15. 3D Design and Analysis of Crushing Roller of High-pressure Grinding Roller

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Crushing roller is one of the main parts of High-p re ssure Grinding Roller, which is a kind of high efficient ore crushing equipment. A kind of assembled roller, which is more convenient to renovate worn surface b y simply replacing segmented surface of the roller, was developed. The structura l models of assembled roller's components were designed with SolidWorks softwar e based on feature modeling, these solid models of the roller were virtually ass embled. Through this work, not only was the assemble i...

  16. A mathematical model for surface roughness of fluidic channels produced by grinding aided electrochemical discharge machining (G-ECDM

    Directory of Open Access Journals (Sweden)

    Ladeesh V. G.

    2017-01-01

    Full Text Available Grinding aided electrochemical discharge machining is a hybrid technique, which combines the grinding action of an abrasive tool and thermal effects of electrochemical discharges to remove material from the workpiece for producing complex contours. The present study focuses on developing fluidic channels on borosilicate glass using G-ECDM and attempts to develop a mathematical model for surface roughness of the machined channel. Preliminary experiments are conducted to study the effect of machining parameters on surface roughness. Voltage, duty factor, frequency and tool feed rate are identified as the significant factors for controlling surface roughness of the channels produced by G-ECDM. A mathematical model was developed for surface roughness by considering the grinding action and thermal effects of electrochemical discharges in material removal. Experiments are conducted to validate the model and the results obtained are in good agreement with that predicted by the model.

  17. Simulation of Flow and Heat Transfer of Mist/Air Impinging Jet on Grinding Work-Piece

    Directory of Open Access Journals (Sweden)

    Fan Jiang

    2016-01-01

    Full Text Available The numerical investigation is presented for flow and heat transfer on grinding work-piece with mist/air impinging jet by using DPM (discrete phase model model. The tracks of the mist droplets show most of them are accumulated on the right surface of grinding zone, and can be influenced by the rotating speed of the grinding wheel, the position and the number of the jet nozzle. The mechanism model of enhance cooling by mist/air impinging jet is developed, which indicated the mist droplet is an key factor of affecting the heat transfer coefficient, and the increasing of mist droplet leads to significant enhancement of the cooling effect. The effects of the jet nozzle location, the nozzle diameter, and the nozzle number on flow and heat transfer coefficient are studied. The results show that the less nozzle distance and inclination angle, the greater nozzle diameter and number lead to greater heat transfer coefficient.

  18. Rapid online measurement method for radius of curvature of fine grinding optics based on tool setting system

    Science.gov (United States)

    Dai, Lei; Zhang, Jian; Gu, Yongqiang; Miao, Erlong

    2016-10-01

    The radius of curvature (ROC) is one of the most important parameters of sphere optic components. In optic fine grinding process, radius of curvature accuracy requires up to 0.1%. We propose a method based on high precision CNC grinding machine, develop ROC online measurement method for fine grinding optics. This rapid method only takes few measurement points based on spiral route path, attaining enough accuracy and reduce the time cost, furthermore, can greatly reduce the repeated installation error. Analyzing the uncertainty sources that affect to the ROC measurement results, calculates the combined standard uncertainty 32.8 micron. Completed comparison experiments with CMM, the standard deviation of the experiment result are about 18 micron that approaches to CMM results.

  19. Effect of Grinding Methods on Structural, Physicochemical, and Functional Properties of Insoluble Dietary Fiber from Orange Peel

    Directory of Open Access Journals (Sweden)

    Yanlong Liu

    2016-01-01

    Full Text Available This study evaluated the effect of grinding methods (regular laboratory milling, ultra centrifugal rotor milling, and ball milling on structural, physicochemical, and functional properties of insoluble dietary fiber (IDF fraction from orange peel. The results demonstrated that both ultra centrifugal milling and ball milling could effectively decrease average particle size of IDF fraction (81.40 μm and 19.63 μm, resp.. The matrix structure of IDF fraction was destroyed but FTIR structure had no major change after grinding. As particle size decreased, the bulk density and lightness of IDF fraction increased and a redistribution of fiber components from insoluble to soluble fractions was observed. Furthermore, ball milled IDF fraction exhibited significantly higher capacity to retard glucose diffusion and inhibit α-amylase activity (35.09%. This work would give useful insight into effect of grinding methods on properties and functions of orange peel IDF in food industry.

  20. Reproducible preparation of nanospray tips for capillary electrophoresis coupled to mass spectrometry using 3D printed grinding device.

    Science.gov (United States)

    Tycova, Anna; Prikryl, Jan; Foret, Frantisek

    2016-04-01

    The use of high quality fused silica capillary nanospray tips is critical for obtaining reliable and reproducible electrospray/MS data; however, reproducible laboratory preparation of such tips is a challenging task. In this work, we report on the design and construction of low-cost grinding device assembled from 3D printed and commercially easily available components. Detailed description and characterization of the grinding device is complemented by freely accessible files in stl and skp format allowing easy laboratory replication of the device. The process of sharpening is aimed at achieving maximal symmetricity, surface smoothness and repeatability of the conus shape. Moreover, the presented grinding device brings possibility to fabricate the nanospray tips of desired dimensions regardless of the commercial availability. On several samples of biological nature (reserpine, rabbit plasma, and the mixture of three aminoacids), performance of fabricated tips is shown on CE coupled to MS analysis. The special interest is paid to the effect of tip sharpness.

  1. 斜轧中铬半钢磨球的冲击疲劳和磨损性%Impact Fatigue Resistance and Abrasiveness of Cross Rolled Medium Chromium Semi-Steel for Grinding Ball

    Institute of Scientific and Technical Information of China (English)

    李慧

    2001-01-01

    The repeated low-energy impact fatigue resistance and abrasiveness of cross rolled 1.85%C - 5.86%Cr medium chromium semi-steel have been studied. The results indicated that the impact fatigue life of cross rolled medium chromium semi-steel grinding ball is higher than that of casting grinding ball, and the higher impact fatigue resistance and abrasiveness of ball could be got by adequate rolled residual heat treated.%通过落球和冲击磨损试验,研究了斜轧1.85%C、5.86%Cr中铬半钢磨球的抗小能量多冲击破坏能力和耐磨性。结果表明:斜轧中铬半钢磨球的冲击疲劳寿命高于铸造半钢磨球。该球经适当的热轧余热热处理,可获得较高的抗多冲击破坏能力与耐磨性能。

  2. Influence of mechanical grinding on lithium insertion and extraction properties of iron silicide/silicon composites

    Science.gov (United States)

    Usui, Hiroyuki; Nouno, Kazuma; Takemoto, Yuya; Nakada, Kengo; Ishii, Akira; Sakaguchi, Hiroki

    2014-12-01

    We prepared composite electrodes of iron silicide/Si by using mechanical grinding for mixtures of ferrosilicon and Si followed by gas-deposition, and investigated their electrochemical properties as Li-ion battery anode. With increasing the mechanical grinding time, the phase transformation from FeSi to FeSi2 took place more significantly, and the composite electrode showed better cycle stabilities. There was no remarkable difference in mechanical properties and electronic conductivity between FeSi and FeSi2. On the other hand, the FeSi2 electrode exhibited about three times larger capacities in comparison with the FeSi electrode. In addition, a result of our first principle calculation indicates that Li-ion can diffuse more easily in FeSi2 lattice than in FeSi lattice. It is suggested that the better cyclability of the composite electrodes was attributed to the moderate reactivity of FeSi2 with Li and the smooth Li-ion diffusion in it.

  3. Composition of corn dry-grind ethanol by-products: DDGS, wet cake, and thin stillage.

    Science.gov (United States)

    Kim, Youngmi; Mosier, Nathan S; Hendrickson, Rick; Ezeji, Thaddeus; Blaschek, Hans; Dien, Bruce; Cotta, Michael; Dale, Bruce; Ladisch, Michael R

    2008-08-01

    DDGS and wet distillers' grains are the major co-products of the dry grind ethanol facilities. As they are mainly used as animal feed, a typical compositional analysis of the DDGS and wet distillers' grains mainly focuses on defining the feedstock's nutritional characteristics. With an increasing demand for fuel ethanol, the DDGS and wet distillers' grains are viewed as a potential bridge feedstock for ethanol production from other cellulosic biomass. The introduction of DDGS or wet distillers' grains as an additional feed to the existing dry grind plants for increased ethanol yield requires a different approach to the compositional analysis of the material. Rather than focusing on its nutritional value, this new approach aims at determining more detailed chemical composition, especially on polymeric sugars such as cellulose, starch and xylan, which release fermentable sugars upon enzymatic hydrolysis. In this paper we present a detailed and complete compositional analysis procedure suggested for DDGS and wet distillers' grains, as well as the resulting compositions completed by three different research groups. Polymeric sugars, crude protein, crude oil and ash contents of DDGS and wet distillers' grains were accurately and reproducibly determined by the compositional analysis procedure described in this paper.

  4. Effects of High Pressure ORE Grinding on the Efficiency of Flotation Operations

    Science.gov (United States)

    Saramak, Daniel; Krawczykowska, Aldona; Młynarczykowska, Anna

    2014-10-01

    This article discusses issues related to the impact of the high pressure comminution process on the efficiency of the copper ore flotation operations. HPGR technology improves the efficiency of mineral resource enrichment through a better liberation of useful components from waste rock as well as more efficient comminution of the material. Research programme included the run of a laboratory flotation process for HPGR crushing products at different levels of operating pressures and moisture content. The test results showed that products of the high-pressure grinding rolls achieved better recoveries in flotation processes and showed a higher grade of useful components in the flotation concentrate, in comparison to the ball mill products. Upgrading curves have also been marked in the following arrangement: the content of useful component in concentrate the floatation recovery. All upgrading curves for HPGR products had a more favourable course in comparison to the curves of conventionally grinded ore. The results also indicate that various values of flotation recoveries have been obtained depending on the machine operating parameters (i.e. the operating pressure), and selected feed properties (moisture).

  5. Priming effects in aggregate size fractions induced by glucose addition and grinding

    Science.gov (United States)

    Tian, Jing; Blagodatskaya, Evgenia; Pausch, Johanna; Kuzaykov, Yakov

    2014-05-01

    It is widely recognized that soil organic matter (SOM) mineralization can be accelerated (positive priming) or retarded (negative priming) by addition of easily available substrates to soil. SOM is a heterogeneous mixture, which contains numerous compounds with different degradability and turnover rates times. Nevertheless, so far, there is still lack of knowledge on identifying single fractions of the SOM as the source of C and N released by priming effects. The aim of this study was to determine the priming effect as related to different aggregate fractions, aggregate disruption and the amounts of substrate. In a 49 days incubation experiment, the soil samples were separated into three aggregate fractions (>2 mm, 2-0.25 mm and 0.25 mm) than in the microaggregates (priming effect increased as added glucose increased in all intact aggregate size, and highest priming effect was observed in >2 mm fraction. However, the magnitude of priming effect response to glucose addition depended on the aggregate size after grinding. This study demonstrates that substrate amounts, aggregate fractionation and grinding can have obvious impacts on priming effect, indicating important implications for understanding SOM cycling and stability.

  6. Effect of grinding and fluoride-gel exposure on strength of ion-exchanged porcelain.

    Science.gov (United States)

    Anusavice, K J; Hojjatie, B; Chang, T C

    1994-08-01

    Strengthening of dental porcelain through a diffusion heat treatment at 450 degrees C of a potassium-enriched, ion-exchange surface coating has been demonstrated in several recent studies. However, little attention has been focused on the potential strength reduction of these materials when the treated surfaces are ground or etched under clinically simulated conditions. The objective of this study was to test the hypothesis that partial removal of the surface layers of ion-exchanged porcelains by grinding or exposure to acidulated fluoride gel will significantly reduce their flexure strength. Nine groups of body porcelain disks were ion-exchanged at 450 degrees C for 30 min. One of these groups was subjected to ion exchange and no further surface treatment. Eight specimen groups were subjected to the following procedures after ion exchange: grinding to depths of 50 microns, 100 microns, 150 microns, 200 microns, and 250 microns, and exposure to acidulated fluoride for 30 min, 60 min, and 300 min. A tenth group (FC) was fired at 960 degrees C and fast-cooled in air, but the disks were not subjected to the ion-exchange treatment. Surface stress was calculated from measured values of cracks induced in the treated surfaces. Fluoride exposure for up to 60 min resulted in a significant decrease in surface compression (P 0.05).

  7. Characterization of the Oum El Khacheb phosphorites (South Tunisia) and enrichment of big rejections by grinding

    Institute of Scientific and Technical Information of China (English)

    Mâamri Alimi Jihen; Abbassi Leila; Batis Harrouch Narjes

    2016-01-01

    In the last decade, the phosphate reserves have started to decrease. In this study, both phosphate of Oum El Khacheb’s (O.E.K) region (South of Tunisia) and its big rejections were characterized mineralogically and chemically by several analysis methods such as the binocular magnifying glass, X-rays diffraction technique, Technicon auto-analyzer, atomic absorption spectroscopy, and carbon sulfur analyzer. Then, this work focuses on the coarse rejections of O.E.K’s phosphorites which can be valorized by the wet grinding method. Therefore, we have used the methodology of experimental research to determine the optimal grinding conditions. Results found by Doelhert matrix are: a duration at about 4 min, a pulp on solid concentration of 45.00%, a number of cycles equals to 60 rpm and 3.87 as the jar’s loading. The enhancement of the weight yields of phosphate recuperation increased significantly by 46.39%from big rejections with 24.60%of P2O5 concentration.

  8. Optimize Operating Conditions on Fine Particle Grinding Process with Vertically Stirred Media Mill

    Science.gov (United States)

    Yang, Yang; Rowson, Neil; Ingram, Andy

    2016-11-01

    Stirred media mill recently is commonly utilized among mining process due to its high stressing intensity and efficiency. However, the relationship between size reduction and flow pattern within the mixing pot is still not fully understand. Thus, this work investigates fine particle grinding process within vertically stirred media mills by altering stirrer geometry, tip speed and solids loading. Positron Emitting Particle Tracking (PEPT) technology is utilized to plot routine of particles velocity map. By tacking trajectory of a single particle movement within the mixing vessel, the overall flow pattern is possible to be plotted. Ground calcium carbonate, a main product of Imerys, is chosen as feeding material (feed size D80 30um) mixed with water to form high viscous suspension. To obtain fine size product (normally D80 approximately 2um), large amount of energy is drawn by grinding mill to break particles through impact, shear attrition or compression or a combination of them. The results indicate higher energy efficient is obtained with more dilute suspension. The optimized stirrer proves more energy-saving performance by altering the slurry circulate. Imerys Minerals Limited.

  9. Experimental Investigation on the Performance of Grinding Assisted Electrochemical Discharge Drilling of Glass

    Directory of Open Access Journals (Sweden)

    Ladeesh V G

    2016-01-01

    Full Text Available Grinding assisted electrochemical discharge drilling (G-ECDD is a novel technique for producing micro and macro holes in brittle materials including advanced ceramics and glass, both efficiently and economically. G-ECDD involves the use of a rotating diamond core drill as the tool in a normal electrochemical discharge machine setup. The material removal happens by a combination of thermal melting due to electric discharges, followed by grinding action of diamond grits and chemical etching action. In this study, the effect of process parameters like voltage, duty cycle, cycle time and electrolyte concentration on material removed (MR was investigated systematically using response surface methodology. Analysis of variance was performed to identify the significant factors and their percentage contribution. The most significant factor was found to be duty cycle followed by voltage, cycle time and concentration. A quadratic mathematical model was developed to predict MR. Tool wear was found for different frequencies and voltages. Higher tool wear was observed for high frequency above 5kHz pulsed DC supply at high voltage of 110V. Tool wear at the end face of the tool was found to be a significant problem affecting the tool life.

  10. Direct dry-grinding synthesis of monodisperse lipophilic CuS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yajuan; Scott, Julie; Chen, Yi-Tzai; Guo, Liangran; Zhao, Mingyang; Wang, Xiaodong [Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, The University of Rhode Island, Kingston, RI 02881 (United States); Lu, Wei, E-mail: weilu@uri.edu [Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, The University of Rhode Island, Kingston, RI 02881 (United States); School of Pharmacy, Fudan University, Shanghai 201203 (China)

    2015-07-15

    Copper sulfide nanoparticles, effective absorbers of near-infrared light, are recently attracting broad interest as a photothermal coupling agent for cancer therapy. Lipophilic copper sulfide nanoparticles are preferred for high performance biomedical applications due to high tissue affinity. Synthesis of lipophilic copper sulfide nanoparticles requires complicated multi-step processes under severe conditions. Here, we describe a new synthetic process, developed by direct dry-grinding of copper(II) acetylacetonate with sulfur under ambient environment at low temperature. The formed CuS nanoparticles are of uniform size, ∼10 nm in diameter, and are monodispersed in chloroform. Each covellite CuS nanocrystal surface is modified with oleylamine through hydrogen bonding between sulfur atoms and amine groups of oleylamine. The nanoparticles demonstrate near-infrared light absorption for photothermal applications. The synthetic methodology described here is more convenient and less extreme than previous methods, and should thus greatly facilitate the preparation of photothermal lipophilic copper sulfide nanomaterials for cancer therapy. - Highlights: • We make lipophilic CuS nanoparticles by mechanical grinding method in large scale. • The reaction condition is studied to obtain high yield and uniform size. • The synthesis does not need nitrogen protection or high temperature. • Lipophilic CuS nanoparticles show significant near-infrared absorbance.

  11. Correlation analysis of motor current and chatter vibration in grinding using complex continuous wavelet coherence

    Science.gov (United States)

    Liu, Yao; Wang, Xiufeng; Lin, Jing; Zhao, Wei

    2016-11-01

    Motor current is an emerging and popular signal which can be used to detect machining chatter with its multiple advantages. To achieve accurate and reliable chatter detection using motor current, it is important to make clear the quantitative relationship between motor current and chatter vibration, which has not yet been studied clearly. In this study, complex continuous wavelet coherence, including cross wavelet transform and wavelet coherence, is applied to the correlation analysis of motor current and chatter vibration in grinding. Experimental results show that complex continuous wavelet coherence performs very well in demonstrating and quantifying the intense correlation between these two signals in frequency, amplitude and phase. When chatter occurs, clear correlations in frequency and amplitude in the chatter frequency band appear and the phase difference of current signal to vibration signal turns from random to stable. The phase lead of the most correlated chatter frequency is the largest. With the further development of chatter, the correlation grows up in intensity and expands to higher order chatter frequency band. The analyzing results confirm that there is a consistent correlation between motor current and vibration signals in the grinding chatter process. However, to achieve accurate and reliable chatter detection using motor current, the frequency response bandwidth of current loop of the feed drive system must be wide enough to response chatter effectively.

  12. Measuring grinding surface roughness based on the sharpness evaluation of colour images

    Science.gov (United States)

    Huaian, Y. I.; Jian, L. I. U.; Enhui, L. U.; Peng, A. O.

    2016-02-01

    Current machine vision-based detection methods for metal surface roughness mainly use the grey values of images for statistical analysis but do not make full use of the colour information and ignore the subjective judgment of the human vision system. To address these problems, this paper proposes a method to measure surface roughness through the sharpness evaluation of colour images. Based on the difference in sharpness of virtual images of colour blocks that are formed on grinding surfaces with different roughness, an algorithm for evaluating the sharpness of colour images that is based on the difference of the RGB colour space was used to develop a correlation model between the sharpness and the surface roughness. The correlation model was analysed under two conditions: constant illumination and varying illumination. The effect of the surface textures of the grinding samples on the image sharpness was also considered, demonstrating the feasibility of the detection method. The results show that the sharpness is strongly correlated with the surface roughness; when the illumination and the surface texture have the same orientation, the sharpness clearly decreases with increasing surface roughness. Under varying illumination, this correlation between the sharpness and surface roughness was highly robust, and the sharpness of each virtual image increased linearly with the illumination. Relative to the detection method for surface roughness using gray level co-occurrence matrix or artificial neural network, the proposed method is convenient, highly accurate and has a wide measurement range.

  13. Production of scallop shell nanoparticles by mechanical grinding as a formaldehyde adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, Shinya, E-mail: syama@mmm.muroran-it.ac.jp [Muroran Institute of Technology, College of Environmental Technology (Japan); Suzuma, Akifumi [Muroran Institute of Technology, Division of Applied Sciences (Japan); Fujimoto, Toshiyuki; Kuga, Yoshikazu [Muroran Institute of Technology, College of Environmental Technology (Japan)

    2013-04-15

    Scallop shells, which are a waste product in the seafood industry, are disposed more than 200,000 ton per year in Hokkaido, Japan. We report effective uses and simple application for discarded shells as a formaldehyde adsorbent. The adsorption performance of scallop shells to remove formaldehyde vapor is investigated. Planetary ball milling under dry conditions and subsequent water addition realize shells with a crystallite size (35-90 nm) and equivalent size of the specific surface area (41-191 nm) in the nanometer range. The comminution properties of the scallop shells, especially the grinding limit, are estimated via a semi-theoretical consideration for the grinding limit. Additionally, the adsorbed amount of gaseous formaldehyde using a self-designed adsorption line is estimated. The nanosized scallop shells exhibit an excellent adsorption performance rather than the feed shell, and the adsorbed amount is positively correlated with the specific surface area of the shell. Hence, scallop shells have potential to adsorb volatile organic compounds.

  14. Behavior analysis, from grinding or not of the teeth of piglets in nursery

    Directory of Open Access Journals (Sweden)

    Gisele Dela Ricci

    2013-12-01

    Full Text Available The establishment of the social hierarchy of piglets after birth is one of the factors responsible for aggressive disputes among swine. This behavior results in lesions on the face of piglets and on the nipple of sows. Methods such as clipping or grinding of teeth procedures are conducted to the reduction of losses related to the welfare and growth performance of the animals. However, this management has been questioned about the pain and stress. Since 2001, The European Union legislation which describes patterns of animal welfare prohibits the handling of clipping or grinding of teeth of piglets as a routine measure. The objective of this study was to evaluate the effect of grinding or not of teeth in piglet behavior in the nursery. Were used to obtain the data: 34 sows and their piglets, with 11.3 on average. The study was conducted during the summer, in the city of Concordia, SC. At birth, the piglets were separated into rooms according to the order of birth and type of treatment directed to the litters. The management of tooth grind was always held on the second day postpartum along with weighing, the tail docking and castration of male piglets. The behavior was obtained with the aid of an ethogram with variables like sleeping, breastfeeding, eating and drinking water, stereotypies, aggression, standing, lying or sitting, playfulness and exploratory behavior. The observations were made during the twenty one and twenty eight days, until weaning. Data were collected in periods of three days during each week, six hours a day and every five minutes. The data were analyzed on a complete randomized block design with repeated measures. We used a mixed model with fixed effects of treatment, shift, week, and their interactions block using the MIXED procedure (SAS Inst. Inc., Cary, NC. The behavior studied is the percentage of animals in the activity when evaluated. The comparison of the mean was performed by Fisher's least significant difference

  15. Study of thread grinding based on the multi-body system theory%基于多体系统理论的螺纹磨削研究

    Institute of Scientific and Technical Information of China (English)

    范晋伟; 金爱韦; 宁堃; 梅钦; 李海涌

    2012-01-01

    将多体系统运动建模方法应用到数控螺纹磨床建模中,建立机床、工件和砂轮的运动关系,推导出多线砂轮磨削螺纹的加工方程.开发螺纹磨削仿真软件,获得螺纹磨削加工G代码,在磨削螺纹的生产中取得了很好的效果.%Applying the multi-body system modeling theory to CNC thread grinder modeling. Deriving multi-line grinding wheel thread processing equation based on movement relationship of machine tool, workpiece and grinding wheel. A thread grinding simulation software is developed, and the generating thread grinding G-code achieves good results in the production of thread grinding.

  16. 房地产企业社会责任管理研究——基于价值嵌入下的CGR整合框架视角%Study On the Management of Real Estate Corporate Social Responsibility——Based on the Perspectives of CGR Integration

    Institute of Scientific and Technical Information of China (English)

    魏国平

    2010-01-01

    目前我国的房地产还处在生命周期的幼年阶段,很多房地产企业还处在原始积累阶段,其交易、许多行为尚未规范,很多企业都把追求利润作为最大目标,导致了企业行为和社责任之间的偏差.究其原因就自身来说除了缺乏社会履行责任的自觉性之外,更为关键的是没有将社会责任的内涵与企业自身状况结合起来,没有认识到企业社会责任、公司治理和组织能力之间的内在机理和关系.基于此,本文将从探讨房地产企业社会责任的现状与原因出发,在公司治理(Corporate Governance)、组织能力(Organizational Capacity)、和社会责任(Corporate Social Responsibility)(三者简称为CGR)的整合框架下研究和分析房地产企业社会责任,提出房地产企业社会责任管理的思路与建议.

  17. Influences of speed of impact grinding mill and speed of classifying impeller on grinding efficiency%冲击式磨机转速和分级叶轮转速对研磨效率的影响

    Institute of Scientific and Technical Information of China (English)

    王珊; 董为民; 陈国鼎

    2013-01-01

    Taking the impact grinding mill as the study objective,the paper theoretically deduced the calculation formula of maximum crushing energy and cut size of the impact grinding mill.Based on the formula of the maximum crushing energy,it analyzed the influence of the mill speed on the grinding efficiency.Meanwhile,based on the calculation formula of the cut size,it analyzed the influence of the speed of the classifying impeller on the grinding efficiency.At last,tests were conducted to verify the above influences.%以冲击式磨机为研究对象,理论推导了冲击式磨机的最大破碎能公式和切割粒径的计算公式.根据最大破碎能公式分析了冲击式磨机转速对研磨效率的影响;根据切割粒径公式分析了分级叶轮转速对研磨效率的影响,并通过试验进行了验证.

  18. Improved Disturbance Observer (DOB) Based Advanced Feedback Control for Optimal Operation of a Mineral Grinding Process%Improved Disturbance Observer (DOB) Based Advanced Feedback Control for Optimal Operation of a Mineral Grinding Process

    Institute of Scientific and Technical Information of China (English)

    周平; 向波; 柴天佑

    2012-01-01

    Advanced feedback control for optimal operation of mineral grinding process is usually based on the model predictive control (MPC) dynamic optimization. Since the MPC does not handle disturbances directly by controller design, it cannot achieve satisfactory effects in controlling complex grinding processes in the presence of strong disturbances and large uncertainties. In this paper, an improved disturbance observer (DOB) based MPC advanced feedback control is proposed to control the multivariable grinding operation. The improved DOB is based on the optimal achievable H 2 performance and can deal with disturbance observation for the nonminimum-phase delay systems. In this DOB-MPC advanced feedback control, the higher-level optimizer computes the optimal operation points by maximize the profit function and passes them to the MPC level. The MPC acts as a presetting controller and is employed to generate proper pre-setpoint for the lower-level basic feedback control system. The DOB acts as a compensator and improves the operation performance by dynamically compensating the setpoints for the basic control system according to the observed various disturbances and plant uncertainties. Several simulations are performed to demonstrate the proposed control method for grinding process operation.

  19. 旋风式砂带磨削机及钢丝磨削试验研究%Research on Cyclone Abrasive Belt Grinding Machine and Steel Wire Grinding Test

    Institute of Scientific and Technical Information of China (English)

    卢剑锋; 李家春; 张萍

    2014-01-01

    Abrasive belt grinder plays an important role in machining field. It can meet a variety of processing requirements. The concept of abrasive belt grinding was introduced briefly. The working principle and main structure of a new belt grinder for removing rust on steel wire surface were illustrated. Then the relationships among the grinding force,the metal removal rate,belt wear rate, grinding ratio,grinding depth and wire walking speed were studied through experiment. The research work provides rational parameters for wire snagging line with abrasive belt.%砂带磨削在机械加工领域发挥着越来越大的作用,可满足各种加工要求。简单介绍了砂带磨削的概念,阐述了一个针对钢丝表面除锈的新型砂带磨削设备的工作原理及其机床的主要机构,并通过试验研究磨削压力、金属去除率、砂带磨损、磨削比、磨削深度、钢丝走速之间的关系,为砂带修磨线材生产线提供了合理的磨削工艺参数。

  20. Preparation of fenofibrate immediate-release tablets involving wet grinding for improved bioavailability.

    Science.gov (United States)

    Zhang, Lili; Chai, Guihong; Zeng, Xueping; He, Haibing; Xu, Hui; Tang, Xing

    2010-09-01

    The purpose of this study was to investigate the dissolution and oral bioavailability of an immediate-release tablet involving wet grinding of a poorly water-soluble drug, fenofibrate. The milled suspension was prepared using a Basket Dispersing Mill in the presence of a hydrophilic polymer solution and then granulated with common excipients, and compressed into an immediate-release tablet with blank microcrystalline cellulose granules. Compared with unmilled tablets (56% within 30 minutes), the dissolution of wet-milled tablets (about 98% in 30 minutes) was markedly enhanced. No significant decrease in the dissolution rate (96% in 30 minutes) of the wet-milled tablet was observed after 3 months under 40 degrees C and 75% relative humidity storage. In addition, the oral bioavailability of the wet-milled tablets (test) and Lipanthyl supra-bioavailability tablets (reference) was determined in beagle dogs after a single dose (160 mg fenofibrate) in a randomized crossover, own-control study. The results suggested that both the area under the plasma concentration-time curve (AUC((0-t)) = 46.83 +/- 11.09 microg/mL h) and the mean peak concentration of the test (C(max) = 4.63 +/- 1.71 microg/mL) were higher than the reference (AUC((0-t)) = 35.12 +/- 10.97 microg/mL h, C(max) = 2.11 +/- 0.08 microg/mL). The relative bioavailability of the wet-milled tablet was approximately 1.3-fold higher. Furthermore, the apparent rate of absorption of fenofibrate from the wet-milled tablet (T(max) = 2.63 hours) was faster than that from Lipanthyl (T(max) = 3.75 hours). These results indicated that the dissolution and the bioavailability of fenofibrate were significantly enhanced by wet-grinding process. So, this shows that wet grinding is a powerful technique to improve the bioavailability for poorly water-soluble drugs, especially for Biopharmaceutics Classification System Class II compounds.

  1. 2D-C/SiC高速深磨磨削特性及去除机制%Investigation of grinding characteristics and removal mechanisms of 2D-C/SiC in high speed deep grinding

    Institute of Scientific and Technical Information of China (English)

    刘杰; 李海滨; 张小彦; 洪智亮; 何宗倍; 张毅; 刘小瀛

    2012-01-01

    The grinding experiments were conducted on 2D-C/SiC composites by using resin bond diamond wheel in this work.The ground surface/subsurface damages were observed.The theory expression of grinding force for the friction layer(surface) of 2D-C/SiC was proposed,and the effect of grinding machining process amount on grinding force and force ratio was also discussed.The result indicates that the removal mechanisms involved in the grinding process for 2D-C/SiC composites are dominated by their brittleness fractures and related to their microstructures,which are different from those of ordinary plastic and brittle materials.%采用树脂结合剂金刚石砂轮,通过对2D-C/SiC复合材料高速深磨磨削加工,并对磨削表面形貌和亚表面损伤进行了观察。提出了2D-C/SiC摩擦层(表面)的磨削力理论公式,讨论了磨削加工用量对磨削力和磨削力比的影响。实验结果表明,2D-C/SiC复合材料的高速深磨材料去除机制与其自身的微观结构相关,既不同于塑性材料,也不同于普通脆性材料,而是以脆性断裂去除为主。

  2. 杯形砂轮磨削高硬度球面砂轮磨损的研究%Grinding Wheel Wear in Grinding of High Hardness Spherical Surface with Cup Wheel

    Institute of Scientific and Technical Information of China (English)

    查体建; 许黎明; 罗睿; 解斌; 时轮

    2013-01-01

    采用分块杯形砂轮磨削高硬度球面,磨削过程中砂轮磨损不仅影响砂轮磨削性能,而且造成工件和砂轮实际接触面积不断产生变化,影响磨削力和磨削质量.为此,基于展成法磨削原理研究砂轮块磨损后的形状变化,分析了分块砂轮的磨损形式,揭示了进给过程中砂轮块磨损形状的变化规律,推导了砂轮磨损量和砂轮工件接触面积的计算公式,分析了砂轮磨损速度的变化趋势及其影响因素,试验最后研究了砂轮磨损量的变化规律,并验证了砂轮磨损量的计算模型.%High hardness sphere is ground by block structured cup wheel. The wheel' s wear not only affect the grinding performance, but also change the contact area between workpiece and wheel, which have great influence on the surface quality and grinding force. The shape of the worn grinding wheel was discussed on the principle of the sphere generating method, and the wear types were also studied. The variation law of the wear shape in the grinding process was studied , and the mathematic models were built for calculation of amount of wheel wear and contact area between wheel and workpiece. The wear rate and the influential factors on the wheel wear were analyzed. At last the experimental results indicated the wear rate, and verified the theory model of grinding wheel wear.

  3. The effect of cryogenic grinding and hammer milling on the flavour quality of ground pepper (Piper nigrum L.).

    Science.gov (United States)

    Liu, Hong; Zeng, Fankui; Wang, Qinghuang; Ou, Shiyi; Tan, Lehe; Gu, Fenglin

    2013-12-15

    In this study, we compared the effects of cryogenic grinding and hammer milling on the flavour attributes of black, white, and green pepper. The flavour attributes were analysed using headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS), sensory evaluation and electronic nose (e-nose) analysis. Cryogenic grinding resulted in minimal damage to the colour, flavour, and sensory attributes of the spices. Cryogenic grinding was also better than hammer milling at preserving the main potent aroma constituents, but the concentrations of the main aroma constituents were dramatically reduced after storing the samples at 4 °C for 6 months. Pattern matching performed by the e-nose further supported our sensory and instrumental findings. Overall, cryogenic grinding was superior to hammer milling for preserving the sensory properties and flavour attributes of pepper without significantly affecting its quality. However, we found that the flavour quality of ground pepper was reduced during storage. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. 实用软压光辊磨削方法%Practical Grinding Method for Soft Calender Roll

    Institute of Scientific and Technical Information of China (English)

    田明德

    2012-01-01

    针对软压光机的软压光辊在生产使用中产生斑马纹的问题,结合材料力学的原理从软压光辊包覆材料疲劳的角度分析斑马纹的形成,分析在机使用的软压光辊表面胶层(厚度约0.2mm的疲劳破坏层、过渡层和未破坏层)的特点,阐述了在软压光辊磨削中的工艺控制方法,总结了一套软压光辊科学的磨削方法,使用该方法可延长软压光辊的在机使用寿命.%The cause of zebra grains on the soft calender roll is described to the material fatigue according to material mechanics principle. There are three outer layers of the soft calender roll, I. E. The serious damaged layer which is almost 0. 2 mm thick, the controlled grinding transition layer and the basic layer which maintains the material character. The methods for grinding these three layers are discussed. The soft calender roll grinding method including lowering down the temperature, recovery deformation, measuring, controlling the grinding amount and finishing is summarized.

  5. Changes in oil content, fatty acid composition, and functional lipid profiles during dry grind ethanol production from corn.

    Science.gov (United States)

    Demand for alternatives to fossil fuels has resulted in a dramatic increase in ethanol production from corn. The dry grind method has been the major process, resulting in a large volume of dried distiller grains with solubles (DDGS) as a co-product. This presentation reports our study to monitor ...

  6. Analysis of the influence of infeed rate and cutting fluid on cylindrical grinding processes using a conventional wheel

    Directory of Open Access Journals (Sweden)

    Bianchi Eduardo Carlos

    2004-01-01

    Full Text Available New worldwide trends such as globalization have rendered grinding processes increasingly important for industry, making it essential to perform in-depth studies of variations in grinding process parameters in the pursuit of greater cost effectiveness. This paper presents a comparative analysis of three different infeed rates, using a conventional grinding wheel on quenched and tempered D2 steel workpieces. Higher infeed rates are known to be correlated with shorter grinding times, rendering the process more economically attractive. Two different coolant fluids, 5% emulsion and pure oil, were used. The tests were carried out using the smallest possible amount of coolant and an optimized 5 mm diameter nozzle. The parameters analyzed were tangential force, specific energy, acoustic emission, roundness error and surface roughness. The surfaces of the workpieces were also examined by scanning electron microscopy (SEM. The results revealed that increased infeed rates could reduce processing times without compromising the quality of the workpiece profile, thereby reducing the cost of the process. The best cutting fluid, albeit more harmful to human health and less environmentally friendly, was found to be pure oil.

  7. Effect of superfine grinding on the physico-chemical, morphological and thermogravimetric properties of Lentinus edodes mushroom powders.

    Science.gov (United States)

    Ming, Jian; Chen, Long; Hong, Hui; Li, Jinlong

    2015-09-01

    Lentinus edodes is an edible mushroom commonly known as shiitake, which is the second most produced and consumed edible mushroom in the world and is an important nutrient source in the human diet. To fully use L. edodes, the mushrooms are occasionally ground into powder as a flavourful and functional food additive. This study produces powders from the cap and stipe of Lentinus edodes mushrooms through superfine grinding. These powders are composed of sub-micron range particles with various size distributions. The superfine grinding process is then compared with shear pulverisation to determine the different effects on both the cap and stipe powders in terms of particle size and physico-chemical, morphological and thermogravimetric properties. When average particle size was reduced to 0.54 and 0.46 µm, respectively, the moisture and protein content, angles of repose and slide, and water holding capacity of the powders decreased to varied extents. However, soluble dietary fibre, water solubility index, and swelling capacity increased. Scanning electron microscope images suggested that the superfine grinding process effectively changed the original surface structure of the L. edodes powders. The curves of thermogravimetric analysis and those of the derivatives of thermogravimetry indicated that superfine grinding can improve the thermostability of L. edodes powders. Furthermore, superfinely ground L. edodes powders may be used as pharmaceutical or food additives in various fields. The present study suggests that superfinely ground L. edodes powders may be applied in various fields as pharmaceutical or food additives. © 2014 Society of Chemical Industry.

  8. Mechanical behavior of a Y-TZP ceramic for monolithic restorations: effect of grinding and low-temperature aging

    NARCIS (Netherlands)

    Pereira, G.K.R.; Silvestri, T.; Camargo, R.; Rippe, M.P.; Amaral, M.; Kleverlaan, C.J.; Valandro, L.F.

    2016-01-01

    This study aimed to investigate the effects of grinding with diamond burs and low-temperature aging on the mechanical behavior (biaxial flexural strength and structural reliability), surface topography, and phase transformation of a Y-TZP ceramic for monolithic dental restorations. Disc-shaped speci

  9. The effect of grinding on the mechanical behavior of Y-TZP ceramics: A systematic review and meta-analyses

    NARCIS (Netherlands)

    Pereira, G.K.R.; Fraga, S.; Montagner, A.F.; Soares, F.Z.M.; Kleverlaan, C.J.; Valandro, L.F.

    2016-01-01

    The aim of this study was to systematically review the literature to assess the effect of grinding on the mechanical properties, structural stability and superficial characteristics of Y-TZP ceramics. The MEDLINE via PubMed and Web of Science (ISI – Web of Knowledge) electronic databases were search

  10. Evaluation of a cross contamination model describing transfer of salmonella spp. and listeria monocytogenes during grinding of pork and beef

    DEFF Research Database (Denmark)

    Møller, Cleide Oliveira de Almeida; Hansen, Tina Beck; Aabo, Søren

    2015-01-01

    Introduction: The cross contamination model (Møller et al. 2012) was evaluated to investigate its capability of describing transfer of Salmonella spp. and Listeria monocytogenes during grinding of pork and beef of varying sizes (50 – 324 g) and numbers of pieces to be ground (10 – 100), in two...

  11. Mechanical behavior of a Y-TZP ceramic for monolithic restorations: effect of grinding and low-temperature aging

    NARCIS (Netherlands)

    Pereira, G.K.R.; Silvestri, T.; Camargo, R.; Rippe, M.P.; Amaral, M.; Kleverlaan, C.J.; Valandro, L.F.

    2016-01-01

    This study aimed to investigate the effects of grinding with diamond burs and low-temperature aging on the mechanical behavior (biaxial flexural strength and structural reliability), surface topography, and phase transformation of a Y-TZP ceramic for monolithic dental restorations. Disc-shaped

  12. An engineering and economic evaluation of quick germ-quick fiber process for dry-grind ethanol facilities: analysis.

    Science.gov (United States)

    Rodríguez, Luis F; Li, Changying; Khanna, Madhu; Spaulding, Aslihan D; Lin, Tao; Eckhoff, Steven R

    2010-07-01

    An engineering economic model, which is mass balanced and compositionally driven, was developed to compare the conventional corn dry-grind process and the pre-fractionation process called quick germ-quick fiber (QQ). In this model, documented in a companion article, the distillers dried grains with solubles (DDGS) price was linked with its protein and fiber content as well as with the long-term average relationship with the corn price. The detailed economic analysis showed that the QQ plant retrofitted from conventional dry-grind ethanol plant reduces the manufacturing cost of ethanol by 13.5 cent/gallon and has net present value of nearly $4 million greater than the conventional dry-grind plant at an interest rate of 4% in 15years. Ethanol and feedstock price sensitivity analysis showed that the QQ plant gains more profits when ethanol price increases than conventional dry-grind ethanol plant. An optimistic analysis of the QQ process suggests that the greater value of the modified DDGS would provide greater resistance to fluctuations in corn price for QQ facilities. This model can be used to provide decision support for ethanol producers.

  13. Characterization of the mechanical properties and structural integrity of T-welded connections repaired by grinding and wet welding

    Energy Technology Data Exchange (ETDEWEB)

    Terán, G., E-mail: gteran@imp.mx [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Cuamatzi-Meléndez, R., E-mail: rcuamatzi@imp.mx [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Albiter, A., E-mail: aalbiter@imp.mx [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Maldonado, C., E-mail: cmzepeda@umich.mx [Instituto de Investigaciones Metalúrgicas, UMSNH, PO Box 52-B, 58000, México (Mexico); Bracarense, A.Q., E-mail: bracarense@ufmg.br [UFMG Departamento de Engeharia Mecánica Belo Horizonte, MG (Brazil)

    2014-04-01

    This paper presents an experimental methodology to characterize the structural integrity and mechanical properties of repaired T-welded connections using in fixed offshore structures. Grinding is employed to remove localized damage like cracking and corrosion and subsequent wet welding can be used to fill the grinded material. But it is important to define the grinding depth and profile in order to maintain structural integrity during the repair. Therefore, in this work different grinding depths were performed, for damage material removal, at the weld toe of the T-welded connections. The grinding was filled by wet welding in a hyperbaric chamber, simulating three different water depths: 50 m, 70 m and 100 m. The electrodes were coated with vinilic varnish, which is cheap and easy to apply. The characterization of the mechanical properties of the T-welded connections was done with standard tensile, hardness and Charpy tests; microstructure and porosity analysis were also performed. The samples were obtained from the welded connections in regions of the wet weld beads. The test results were compared with the mechanical properties of the T-welded connections welded in air conditions performed by other authors. The results showed that the wet welding technique performed in this work produced good mechanical properties of the repaired T-welded connection. The mechanical properties, measured in wet conditions, for 6 mm grinding depth, were similar for the 3 different water depths measured in air conditions. But for 10 mm grinding depth, the values of the mechanical properties measured in wet conditions were quite lower than that for air conditions for the 3 water depths. However a porosity analysis, performed with a Scanning Electronic Microscopy (SEM), showed that the level of porosity in the resulted wet weld beads is in the range of that published in the literature and some samples revealed lower level of porosity. The main resulting microstructure was polygonal

  14. ASSESSMENT OF SELECTED PROPERTIES OF NORMAL CONCRETES WITH THE GRINDED RUBBER FROM WORN OUT VEHICLE TYRES

    Directory of Open Access Journals (Sweden)

    Ewa Ołdakowska

    2015-07-01

    Full Text Available Rubber from the worn tyres is associated with a useless material, strenuous for environment, whose most popular recovery method until recently was storage (currently forbidden by law. The adoption and dissemination of new ecological standards, created not only by the European and national legislation, but also developing as a result of expanding ecological consciousness, forces the necessity of seeking efficient methods of utilization of the vehicle tyres. The exemplary solution for the problem of tyres withdrawn from the operation, presented in the article, is using them in the grinded form as a substitute for the natural aggregate for the production of normal concrete. The article presents the results of the tests of selected properties of the modified normal concrete, upon the basis of which it has been found that the rubber causes decrease of compression strength, concrete weight, limits water absorbability, and does not influence significantly the physical and chemical phenomena accompanying the composite structure formation.

  15. Gluten-containing grains skew gluten assessment in oats due to sample grind non-homogeneity.

    Science.gov (United States)

    Fritz, Ronald D; Chen, Yumin; Contreras, Veronica

    2017-02-01

    Oats are easily contaminated with gluten-rich kernels of wheat, rye and barley. These contaminants are like gluten 'pills', shown here to skew gluten analysis results. Using R-Biopharm R5 ELISA, we quantified gluten in gluten-free oatmeal servings from an in-market survey. For samples with a 5-20ppm reading on a first test, replicate analyses provided results ranging 160ppm. This suggests sample grinding may inadequately disperse gluten to allow a single accurate gluten assessment. To ascertain this, and characterize the distribution of 0.25-g gluten test results for kernel contaminated oats, twelve 50g samples of pure oats, each spiked with a wheat kernel, showed that 0.25g test results followed log-normal-like distributions. With this, we estimate probabilities of mis-assessment for a 'single measure/sample' relative to the gluten content.

  16. En route to a multi-model scheme for clinker comminution with chemical grinding aids

    CERN Document Server

    Mishra, R K; Carmona, H A; Wittel, F K; Sawley, M L; Weibel, M; Gallucci, E; Herrmann, H J; Heinz, H; Flatt, R J

    2015-01-01

    We present a multi-model simulation approach, targeted at understanding the behavior of comminution and the effect of grinding aids (GAs) in industrial cement mills. On the atomistic scale we use Molecular Dynamics (MD) simulations with validated force field models to quantify elastic and structural properties, cleavage energies as well as the organic interactions with mineral surfaces. Simulations based on the Discrete Element Method (DEM) are used to integrate the information gained from MD simulations into the clinker particle behavior at larger scales. Computed impact energy distributions from DEM mill simulations can serve as a link between large-scale industrial and laboratory sized mills. They also provide the required input for particle impact fragmentation models. Such a multi-scale, multi-model methodology paves the way for a structured approach to the design of chemical additives aimed at improving mill performance.

  17. Photoluminescence of MoS2 Prepared by Effective Grinding-Assisted Sonication Exfoliation

    Directory of Open Access Journals (Sweden)

    Jing-Yuan Wu

    2014-01-01

    Full Text Available Exfoliation of bulk molybdenum disulfide (MoS2 using sonication in appropriate solvent is a promising route to large-scale preparation of few-layered or monolayered crystals. Grinding-assisted sonication exfoliation was used for preparing monolayered MoS2 nanosheets from natural mineral molybdenite. By controlling the sonication time, larger crystallites could be further exfoliated to smaller as well as thinner nanosheets without damaging their structures. The concentration of 1.6 mg mL−1 of final solution could be achieved. Several microscopic techniques like scanning electron microscopy, transmission electron microscopy, and atomic force microscopy were employed to evaluate the exfoliation results. Strong photoluminescence with the peak centered at 440 nm was also observed in the resulting dispersion which included several small lateral-sized (~3 nm nanostructures.

  18. Finishing of additively manufactured titanium alloy by shape adaptive grinding (SAG)

    Science.gov (United States)

    Beaucamp, Anthony T.; Namba, Yoshiharu; Charlton, Phillip; Jain, Samyak; Graziano, Arthur A.

    2015-06-01

    In recent years, rapid prototyping of titanium alloy components for medical and aeronautics application has become viable thanks to advances in technologies such as electron beam melting (EBM) and selective laser sintering (SLS). However, for many applications the high surface roughness generated by additive manufacturing techniques demands a post-finishing operation to improve the surface quality prior to usage. In this paper, the novel shape adaptive grinding process has been applied to finishing titanium alloy (Ti6Al4V) additively manufactured by EBM and SLS. It is shown that the micro-structured surface layer resulting from the melting process can be removed, and the surface can then be smoothed down to less than 10 nm Ra (starting from 4-5 μm Ra) using only three different diamond grit sizes. This paper also demonstrates application of the technology to freeform shapes, and documents the dimensional accuracy of finished artifacts.

  19. Direct Dry-Grinding Synthesis of Monodisperse Lipophilic CuS Nanoparticles.

    Science.gov (United States)

    Li, Yajuan; Scott, Julie; Chen, Yi-Tzai; Guo, Liangran; Zhao, Mingyang; Wang, Xiaodong; Lu, Wei

    2015-07-15

    Copper sulfide nanoparticles, effective absorbers of near-infrared light, are recently attracting broad interest as a photothermal coupling agent for cancer therapy. Lipophilic copper sulfide nanoparticles are preferred for high performance biomedical applications due to high tissue affinity. Synthesis of lipophilic copper sulfide nanoparticles requires complicated multi-step processes under severe conditions. Here, we describe a new synthetic process, developed by direct dry-grinding of copper(II) acetylacetonate with sulfur under ambient environment at low temperature. The formed CuS nanoparticles are of uniform size, ~10 nm in diameter, and are monodispersed in chloroform. Each covellite CuS nanocrystal surface is modified with oleylamine through hydrogen bonding between sulfur atoms and amine groups of oleylamine. The nanoparticles demonstrate near-infrared light absorption for photothermal applications. The synthetic methodology described here is more convenient and less extreme than previous methods, and should thus greatly facilitate the preparation of photothermal lipophilic copper sulfide nanomaterials for cancer therapy.

  20. Evaluation of the effects of coal grinding in terms of coal water slurry preparation

    Directory of Open Access Journals (Sweden)

    Robak Jolanta

    2016-01-01

    Full Text Available Coal Water Slurry (CWS is a specific form of solid fuel. It occurs in the form of finely ground coal particles and water. Depending on the use, the content of combustible matter is from 40 to 70% by weight. The attractiveness of the fuel is primarily its properties, i.e. liquid form, high energy efficiency (for water evaporation 4% energy is used – for CSW with 70% concentration of coal, decreased environmental impurities (lower NOx emission and reduced risk of explosion. The advantages of CWS fuels, the possibility of independence from petrochemical fuels, wide availability of coal and emphasis on the use of cleaner technologies are the driving force for development of slurry fuel technologies. The major parameters characterizing the fuel suspension are: solid phase concentration (share of coal in the slurry expressed as either weight or volume fraction of dry coal, time stability (resistance to delamination and separation of the dispersed phase from the continuous phase and viscosity, determining the flow of suspension. The mentioned parameters are dependent on the susceptibility of coal for production of aqueous suspensions (slurrability, conditioned by natural properties of coal, such as: coalification degree, petrographic composition and surface properties. They are also dependent on the slurry fuel preparation process: particle size, solid phase concentration, used additives (stabilizing and dispersion agents and modification of primary coal properties (ash removal, change of surface properties. Preparation of sustainable, high concentrated CWS fuel coal is promoted by the hydrophobic nature of the coal surface, characteristic for coals of higher coalification. A great technological problem is to obtain a highly concentrated coal slurry fuel from less coalified hydrophilic steam coals. The paper presents the results of lab scale research on the CWS prepared from Polish steam coal by wet grinding in mill drum and vibrating. The milling

  1. Changes in mineral concentrations and phosphorus profile during dry-grind processing of corn into ethanol.

    Science.gov (United States)

    Liu, KeShun; Han, Jianchun

    2011-02-01

    For determining variation in mineral composition and phosphorus (P) profile among streams of dry-grind ethanol production, samples of ground corn, intermediate streams, and distillers dried grains with solubles (DDGS) were obtained from three commercial plants. Most attributes (dry matter concentrations) increased significantly from corn to cooked slurry but fermentation caused most significant increase in all attributes. During centrifugation, more minerals went into thin stillage than wet grains, making minerals most concentrated in the former. Mineral increase in DDGS over corn was about 3 fold, except for Na, S, Ca, and Fe. The first three had much higher fold of increase, presumably due to exogenous addition. During fermentation, phytate P and inorganic P had 2.54 and 10.37 fold of increase over corn, respectively, while relative to total P, % phytate P decreased and % inorganic P increased significantly. These observations suggest that phytate underwent some degradation, presumably due to activity of yeast phytase.

  2. Numerical and experimental hydrodynamic study of a coolant distributor for grinding applications

    Directory of Open Access Journals (Sweden)

    Tala Moussa

    2016-01-01

    Full Text Available In grinding, the high frictional energy is converted into heat, which may cause thermal damage and degradation of the wheel and the workpiece. Unwanted thermal effects must thus be reduced, often by external cooling using a curved-duct coolant distributor to match the wheel geometry. The performance of such a system depends strongly on the impinging jet flow properties to ensure efficient sprinkling of the hot spots. The fluid distributor, placed above the workpiece, is pierced with a certain number of identical nozzle fittings, providing multiple jets at the outlet of the nozzles. These jets sprinkle the solids over a given zone and remove the heat by convective transfer. The cooling is hence dependent on the flow structure, meaning the jet diameters, trajectories and velocities, determined up-flow by the distributor design. The present study is devoted to the hydrodynamics aspects of the fluid distributor, aiming to determine the flow-rate distribution at the different orifices and the flow-rate–pressure relationship, for a variety of nozzle diameters and feeding flow rates, under isothermal conditions. A simple hydraulic balance in the device was not able to predict with sufficient accuracy the actual measurements, even when the Venturi effect was accounted for. This discrepancy is due to the curvature of the distributor, inducing secondary flows in interaction with the nozzle outlets, which leads to a rather complex flow pattern. To overcome this issue, a computational fluid dynamics (CFD tool was used and compared with in situ experiments – global flow rate and pressure measurements were additionally taken with particle image velocimetry (PIV to gain insight into the local structure. Simulations were performed with a 3D turbulence model for Reynolds numbers up to 100,000. This model provides an efficient tool for coupling with the thermal study at a later step, allowing global sizing and energetic optimization of the grinding process.

  3. Extracting gold from pyrite roster cinder by ultra-fine-grinding and resin-in-pulp

    Institute of Scientific and Technical Information of China (English)

    危俊婷; 严规有; 郭炳昆; 高桂兰

    2003-01-01

    The ultra-fine-grinding and resin-in-pulp with pH value of 10 are used to extract gold from pyrite roster cinder. During leaching process, aluminium oxide ball is used as stirring medium, hydrogen peroxide as leaching agent and sodium hexametaphosphate as grinding agent. With AM-26 resin as absorber and sulfocarbamide as eluent, gold is recovered from cyanide pulp of pyrite roster cinder by resin-in-pulp. The effects of contact time, temperature and acidity etc. on the gold absorption are investigated by static methods and dynamic method respectively. The effects of flow rate of solution on dynamic adsorption and elution of gold are studied. The results show that AM-26 resin has good adsorbability in cyanide solution, and gold can be easily eluated from the loaded resin with 0. 1mol/L hydrochloric acid and lmol/L sulfocabamide. The adsorption rate and the elution of gold exceed 98%. When leaching time is 2 h, mass ratio of liquid to solid 4: 1, consumption of sodium cyanide 3 kg/t, concentration of hydrogen peroxide and sodium hexametaphosphate 0. 05% respectively, adsorption time 30 min, temperature 10-30 ℃, volume of resin 3 mL, ratio of eluent to resin (10-20): 1, velocity of eluent 1.5 mL/min, the leaching rate of gold reaches 85%. Compared with traditional leaching technology, it can reduce leaching time, avoid complex filter process, decrease sodium cyanide consumption and increase leaching rate of gold by 35%.

  4. Differential activity patterns in the masseter muscle under simulated clenching and grinding forces.

    Science.gov (United States)

    Schindler, H J; Türp, J C; Blaser, R; Lenz, J

    2005-08-01

    The aim of this study was to investigate (i) whether the masseter muscle shows differential activation under experimental conditions which simulate force generation during clenching and grinding activities; and (ii) whether there are (a) preferentially active muscle regions or (b) force directions which show enhanced muscle activation. To answer these questions, the electromyographic (EMG) activity of the right masseter muscle was recorded with five intramuscular electrodes placed in two deep muscle areas and in three surface regions. Intraoral force transfer and force measurement were achieved by a central bearing pin device equipped with three strain gauges (SG). The activity distribution in the muscle was recorded in four different mandibular positions (central, left, right, anterior). In each position, maximum voluntary contraction (MVC) was exerted in vertical, posterior, anterior, medial and lateral directions. The investigated muscle regions showed different amount of EMG activity. The relative intensity of the activation, with respect to other regions, changed depending on the task. In other words, the muscle regions demonstrated heterogeneous changes of the EMG pattern for the various motor tasks. The resultant force vectors demonstrated similar amounts in all horizontal bite directions. Protrusive force directions revealed the highest relative activation of the masseter muscle. The posterior deep muscle region seemed to be the most active compartment during the different motor tasks. The results indicate a heterogeneous activation of the masseter muscle under test conditions simulating force generation during clenching and grinding. Protrusively directed bite forces were accompanied by the highest activation in the muscle, with the posterior deep region as the most active area.

  5. Research on orthogonal experiment of cement grinding%水泥助磨剂的正交试验研究

    Institute of Scientific and Technical Information of China (English)

    林远煌; 彭春元; 许显坚; 韩映忠; 张璐

    2011-01-01

    采用正交试验方法研究助磨剂对水泥的物理力学性能影响.利用数学软件SAS分析系统,定量地分析粉磨时间、助磨剂掺量、水泥组分含量三因素及其不同水平对水泥细度及强度的影响.结果表明,正交设计的分析结果与试验验证结果有良好的一致性,采用较高的粉煤灰掺量,较低的熟料掺量,适当的粉磨时间和助磨剂掺量可以配制优质P.O42.5R的水泥.%The influence on the grinding aids to the physical mechanics function of the cement was researched by the orthogonal experimental method. The mathematical software SAS was used, the effects of the three factors ( grinding time, the mixing quantity of the grinding aids, cement component content ) and their different levels to the cement fineness and strength were quantitatively analysed. The results showed that the good consistency existed with the orthogonal design and the experimental testing results. The cement of high quality P.O42.5R could be prepared with high fly ash mixed, low clinker content, appropriate grinding time and the mixing quan- tity of the grinding aids.

  6. Polar-coordinate Constant Velocity CNC Grinding of Arbitrary Cam Curves%任意凸轮曲线的极坐标式等速CNC磨削

    Institute of Scientific and Technical Information of China (English)

    来传远; 金建新; 唐小琦

    2001-01-01

    The radius change rate of cams and the large diameter of grinding wheels are main factors to effect the grinding quality during grinding enclosed profile curves of cams on the polar-coordinate CNC grinder.To solve problems of the wheel interference and the linear speed change on grinding points which has an effeet on the grinding surface roughness,a polar-coordinate-based equal step interpolating method for the grinding point trace is presented.The method can be applied to the CNC grinding of any regular curves with C1 continuity.%在极坐标式CNC磨床上磨削封闭式凸轮轮廓曲线时,凸轮的半径变化率和砂轮的大直径成为影响磨削质量的主要因素。为解决砂轮干涉及磨削点处线速度变化影响磨削表面粗糙度的问题,提出了极坐标下砂轮磨削点轨迹的等步长插补方法,该方法可应用于任何具有C1连续性的正则曲线的CNC磨削。

  7. Ultrasonic Vibration Assisted Grinding of Bio-ceramic Materials: Modeling, Simulation, and Experimental Investigations on Edge Chipping

    Science.gov (United States)

    Tesfay, Hayelom D.

    Bio-ceramics are those engineered materials that find their applications in the field of biomedical engineering or medicine. They have been widely used in dental restorations, repairing bones, joint replacements, pacemakers, kidney dialysis machines, and respirators. etc. due to their physico-chemical properties, such as excellent corrosion resistance, good biocompatibility, high strength and high wear resistance. Because of their inherent brittleness and hardness nature they are difficult to machine to exact sizes and dimensions. Abrasive machining processes such as grinding is one of the most widely used manufacturing processes for bioceramics. However, the principal technical challenge resulted from these machining is edge chipping. Edge chipping is a common edge failure commonly observed during the machining of bio-ceramic materials. The presence of edge chipping on bio-ceramic products affects dimensional accuracy, increases manufacturing cost, hider their industrial applications and causes potential failure during service. To overcome these technological challenges, a new ultrasonic vibration-assisted grinding (UVAG) manufacturing method has been developed and employed in this research. The ultimate aim of this study is to develop a new cost-effective manufacturing process relevant to eliminate edge chippings in grinding of bio-ceramic materials. In this dissertation, comprehensive investigations will be carried out using experimental, theoretical, and numerical approaches to evaluate the effect of ultrasonic vibrations on edge chipping of bioceramics. Moreover, effects of nine input variables (static load, vibration frequency, grinding depth, spindle speed, grinding distance, tool speed, grain size, grain number, and vibration amplitude) on edge chipping will be studied based on the developed models. Following a description of previous research and existing approaches, a series of experimental tests on three bio-ceramic materials (Lava, partially fired Lava

  8. FY 1998 annual report on the development of laser-aided, noncontacting, realtime, in-process dressing method using a grinding stone with ultrafine abrasive grains, and study on techniques for applying the method to grinding stone of superthin blades; 1998 nendo laser wo mochiita choteiryu toishi no hisesshoku real time inprocess dressing ho no kaihatsu oyobi gokuusuha toishi eno tekiyo gijutsu ni kansuru kenkyu chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    A new noncontacting dressing method using a laser as a tool has been studied and developed, in order to develop environment-compatible, energy-saving type machining machines. In this study, a cup-shaped grinding stone is developed for grinding performance testing by micron-order diamond abrasive powder, used for producing a grinding stone of superthin blades, is mixed with a cast iron binder, molded and sintered. In the grinding performance test, zirconia as a work is ground at a constant pressure to the grinding stone working surface before and after the laser-aided dressing, to analyze grinding/removal efficiency and grinding resistance. The grinding stone working surface conditions are observed by a scanning electron microscope after the laser-aided dressing, to correlate the surface conditions with the grinding data. It is found that the laser-aided dressing method needs no lubricant, is clean, cutting grinding time when incorporated in the machining process, suitable for grinding stone of low stiffness and ultrathin blades by use of ultrafine abrasive grains, suffering no exfoliation of the diamond grains, and hence economical. (NEDO)

  9. 氧化碱木质素制备高效水泥助磨剂%Evaluation of High-performance Grinding Aid for Cement Prepared from Oxidized Alkali Lignin

    Institute of Scientific and Technical Information of China (English)

    周明松; 周莉莉; 伍思龙; 杨东杰; 潘兵; 邱学青

    2011-01-01

    The ammonium persulfate is used to oxidize the alkali lignin to prepare oxidized alkali lignin with low molecular weight and more polar functional groups. The prepared high-performance lignin-based grinding aid GCL6 -J is evaluated by grinding experiment,and the results show that the 45 μm screen residue values of the milled cements decrease from 7. 8% to 5. 3% at the dosage of 0.1% (the mass fraction in the total clinker and composite materials),which is equivalent to the 89. 3% grinding effect of triethanolamine. The long-term breaking and compression strengths of the milled cement using GCL6 - J reach or exceed those of triethanolamine. The combination property evaluation indicates that the GCL6 - J is a kind of lignin-based high-performance grinding aid. The XPS spectrum analysis shows that the thickness of the adsorption layer of the oxidized alkali lignin is 1.02 nm(calculated by the Si),while that of the alkali lignin is 0.41 ran. The Cls content of the milled cement using GCL6 - J decreases from 38. 11 % (blank) to 34. 07% , while the Ca2p and Si2/p contents increase from 8.51% and 4.42% (blank) to 10.29% and 4. 98% ,respectively, which demonstrates the grinding mechanism of GCL6 - J in the milling process: it adsorbs on the new-born high energy active sites of the cement surface and masks the charge.%采用过硫酸铵氧化改性的方法降低碱木质素的相对分子质量(简称分子量,下同),增加其分子中的极性基团,制备改性碱木质素基水泥助磨剂GCL6-J,在添加质量分数0.1%(占熟料和混合材料的质量)时使粉磨水泥的45 μm筛余值由空白的7.8%降低到5.3%,其助磨效能达到三乙醇胺的89.3%,其对水泥的后期抗折抗压强度达到或超过三乙醇胺,综合性能测定表明,GCL6-J属于一种木质素基高效水泥助磨剂.XPS能谱分析表明,氧化改性使碱木质素在水泥表面的吸附层厚度由氧化前的0.41 nm增加为1.02 nm(以硅原子的能谱分析统计);

  10. Effects of different grinding levels (particle size of soybean hull on starting pigs performance and digestibility

    Directory of Open Access Journals (Sweden)

    Ivan Moreira

    2009-10-01

    Full Text Available Two experiments were carried out to study the effects of grinding of soybean hulls (SH on starting pigs (15-30 kg diets. Experiment I consisted of a digestibility trial with 12 barrows, initial average body weight 21.9±1.29 kg, in which the best digestibility coefficient (DC of DM and GE was obtained with SH ground through a 2.5mm screen mesh, evaluated for CP and ME, a best DC was attained with 3.0 mm screen mesh. In the Experiment II, five diets with increasing SH (2.5 mm levels (0, 3, 6, 9 and 12 % for starting piglets were formulated. A quadratic response in daily weight gain (DWG occurred, according to SH inclusion. Worst DWG occurred at 7.75 % SH inclusion. Daily feed intake, feed: gain ratio and plasma urea nitrogen were not affected by inclusion levels. In conclusion, although soybean hull grinding improves the digestible nutrients, inclusion of SH on starting pig diets is economically unfeasible.Foram conduzidos dois experimentos para estudar os efeitos da moagem da casca de soja (CS nas dietas de leitões na fase inicial (15-30 kg. O Experimento I consistiu de um ensaio de digestibilidade com 12 suínos machos castrados, com peso inicial médio de 21,9±1,29 kg. O melhor coeficiente de digestibilidade (CD da MS e EB foi obtido com a peneira 3,0 mm. No Experimento II, foram formuladas cinco dietas com níveis crescentes (0, 3, 6, 9 e 12% de CS (2,5 mm para suínos na fase inicial. Foi obtida resposta quadrática para ganho diário de peso (GDP em função dos níveis crescentes de CS. Pior GDP ocorreu com 7,75 % de inclusão de CS. Consumo diário de ração, conversão alimentar e nitrogênio da uréia plasmática não foram influenciados pela inclusão da CS. Conclui-se que, embora a moagem melhore a digestibilidade dos nutrientes da casca de soja, a sua inclusão nas dietas de suínos na fase inicial é economicamente inviável.

  11. Changes in the aromatic profile of espresso coffee as a function of the grinding grade and extraction time: a study by the electronic nose system.

    Science.gov (United States)

    Severini, C; Ricci, I; Marone, M; Derossi, A; De Pilli, T

    2015-03-01

    The changes in chemical attributes and aromatic profile of espresso coffee (EC) were studied taking into account the extraction time and grinding level as independent variables. Particularly, using an electronic nose system, the changes of the global aromatic profile of EC were highlighted. The results shown as the major amounts of organic acids, solids, and caffeine were extracted in the first 8 s of percolation. The grinding grade significantly affected the quality of EC probably as an effect of the particle size distribution and the percolation pathways of water through the coffee cake. The use of an electronic nose system allowed us to discriminate the fractions of the brew as a function of the percolation time and also the regular coffee obtained from different grinding grades. Particularly, the aromatic profile of a regular coffee (25 mL) was significantly affected by the grinding level of the coffee grounds and percolation time, which are two variables under the control of the bar operator.

  12. Morphology of Near- and Semispherical Melted Chips after the Grinding Processes Using Sol-Gel Abrasives Based on SEM-Imaging and Analysis

    Directory of Open Access Journals (Sweden)

    W. Kapłonek

    2016-01-01

    Full Text Available Selected issues related to SEM-imaging and image analysis of spherical melted chips formed during the grinding process are presented and discussed. The general characteristics of this specific group of machining products are given. Chip formation phenomena, as well as their overall morphology, are presented using selected examples of near- and semispherical melted chips occurring singly or concentrated in clusters on the grinding wheel surface after the machining process. Observation of the spherical melted chips and acquisition of their images were carried out for grinding wheel active surfaces with microcrystalline sintered corundum abrasive grains SG™ after the internal cylindrical grinding process of a 100Cr6 steel and Titanium Grade 2® alloy by use of a scanning electron microscope, JEOL JSM-5500LV. Analysis of the obtained SEM micrographs was carried out by Image-Pro® Plus 5.0 software to determine the selected geometrical parameters describing the morphological features of the assessed chips.

  13. INFLUENCE OF TECHNOLOGICAL MODES OF MAGNETIC-ELECTRIC GRINDING ON MICROSTRUCTURE OF GAS-THERMAL SPRAYED NI–CR–B–SI-COATINGS

    OpenAIRE

    N. V. Spiridonov; M. V. Niaroda; I. O. Sokorov; A. A. Barkun

    2009-01-01

    Influence of technological modes of magnetic-electric grinding on structural changes in a surface layer of gas-thermal sprayed coatings is investigated in the paper. The paper presents optimum modes of  coating roughing and finishing processes.

  14. Nanosized manganese oxide as cathode material for lithium batteries: Influence of carbon mixing and grinding on cyclability

    Science.gov (United States)

    Ibarra-Palos, A.; Strobel, P.; Darie, C.; Bacia, M.; Soupart, J. B.

    New manganese oxi-iodides were prepared by redox reaction of sodium permanganate with lithium iodide in aqueous medium at room temperature. The effects of Li/Mn ratio, carbon incorporation at the synthesis stage and grinding were systematically studied. Structural characterization showed that these materials are nanocrystalline. Best electrochemical results were obtained either on samples with carbon mixed after synthesized, submitted to extensive grinding before electrode fabrication, or on samples for which carbon black was incorporated directly in the aqueous reaction medium at the synthesis stage. Typical capacities in the potential window 1.8-3.8 V are160 and 130 mAh g -1 at the 40th and 100th cycle, respectively.

  15. Application of mechano-chemical synthesis for protective coating on steel grinding media prior to ball milling of copper

    Indian Academy of Sciences (India)

    Indranil Lahiri; K Balasubramanian

    2007-04-01

    One of the major sources of contamination during mechanical milling/alloying is from the surface erosion of the container and the grinding medium. This can either be prevented by using grinding medium and container of same material of the milled material or by adding a coating of the milled material on them. The paper describes the observations made during a mechano-chemical reaction, being used for coating the balls and vials in a planetary ball mill. Visual observation, XRD, optical micrography and EDS analysis were used to understand the progress of the reaction. Copper was successfully coated on the steel balls and vials. The method can easily be adopted in daily production purposes, prior to mechanical milling of a Cu-based powder for prevention of Fe contamination.

  16. An engineering and economic evaluation of wet and dry pre-fractionation processes for dry-grind ethanol facilities.

    Science.gov (United States)

    Lin, Tao; Rodríguez, Luis F; Li, Changying; Eckhoff, Steven R

    2011-10-01

    An engineering-economic model was developed to compare the profitability of the wet fractionation process, a generic dry fractionation process, and the conventional dry grind process. Under market conditions as of January 2011, only fractionation processes generated a positive cash flow. Reduced unit manufacturing costs and increased ethanol production capacity were two major contributions. Corn and ethanol price sensitivity analysis showed that the wet fractionation process always outperformed a generic dry fractionation process at any scenario considered in this research. A generic dry fractionation process would provide better economic performance than the conventional dry grind process if corn price was low and ethanol price was high. All three processes would perform more resiliently if the DDGS price was determined by its composition. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. 基于赫兹理论的弹性磨具磨抛M300钢表面参数模型研究%Study on the Parameter Model of Grinding and Polishing the M300 Steel Surface by Elastic Abrasive Tools Based on Hertz Theory

    Institute of Scientific and Technical Information of China (English)

    吴晓君; 刘睿平; 于兴展; 武倩

    2015-01-01

    目的:由于弹性磨具与曲面接触特征的多样性,导致弹性磨具呈非常量磨损,使磨具的磨抛工况变得复杂,磨抛参数对表面精度的影响没有得到理论上的阐释,通过实验研究磨削过程的磨削参数变化规律与加工表面残留峰移除量的理论关系。方法针对M300钢高耐磨性的特点,通过对球头弹性磨具(油石)的微观接触分析,根据赫兹理论接触应力分布特点,数学推导得出在平面情况下残留峰移除率与影响磨削精度的主要参数的函数关系。结果根据磨削参数变化规律,考虑进给速度的变化,得出任一点的残留峰置的变化量为接触半径减去球头在一定位置下通过的距离,并推导出移除率Q=dh/dt=CPmατnα的预估参数值。根据最小二乘法算得当m=-3,n=-2时,C=1.55×105,移除面积与磨抛参数成正相关。结论通过磨削实验确定移除率待定参数值,从理论上确定影响磨削质量的法向压力和切应力对残留峰移除高度的影响,为曲面磨削弹性预估补偿研究提供参考。同时应适当减小弹性模量,增大法相压力及球头磨具半径,使得进给量增大,减小磨损,提高磨削效率。%ABSTRACT:Objective To study the theoretical relationship between the variation of grinding parameter and the removed amount of residual peak in grinding and polishing process by experiment in the context that the diversity of characteristics in contact with bend surface results in the irregular wear abrasion of elastic tools and complicates abrasive machining status and there is no theoreti-cal interpretation on the effect of grinding parameters on polishing accuracy. Methods Specific to the feature of high abrasion resist-ance of M300 steel, the analysis of the micro-contact of elastic ball abrasive tool ( whetstone) was conducted. Based on the features of contact stress distribution described in the Hertz theory, the functional relationship was mathematically

  18. Optimized Combination of Residue Hydrodesulfurization and Residue Fluid Catalytic Cracking

    Institute of Scientific and Technical Information of China (English)

    Chen Junwu

    2003-01-01

    @@1 Introduction Combination of residue hydrodesulfurization (HDS) and resi-due fluid catalytic cracking (RFCC) is a unique technologyfor processing high-sulfur residue. This paper discusses theoptimized combination of these two processes.

  19. A comparative study of precision finishing of rebuild engine valve faces using micro-grinding and ECH

    OpenAIRE

    Singh, Harpreet; Jain, Pramod Kumar

    2015-01-01

    This paper presents a comparative analysis of process performance of micro-grinding and electrochemical honing, with the aim to achieve higher precision and surface quality of rebuild surfaces of the engine valve face. The discarded engine valve face was rebuilt using plasma transferred arc cladding technique and its surface finish was evaluated in terms of average roughness and maximum roughness value. The improvement in profile error and total run-out were used to evaluate the optimum proce...

  20. Leaching of indium from obsolete liquid crystal displays: Comparing grinding with electrical disintegration in context of LCA

    Energy Technology Data Exchange (ETDEWEB)

    Dodbiba, Gjergj, E-mail: dodbiba@sys.t.u-tokyo.ac.jp [Department of System Innovation, Graduate School of Engineering, University of Tokyo (Japan); Nagai, Hiroki; Wang Lipang; Okaya, Katsunori; Fujita, Toyohisa [Department of System Innovation, Graduate School of Engineering, University of Tokyo (Japan)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Two pre-treatment methods, prior to leaching of indium from obsolete LCD modules, were described. Black-Right-Pointing-Pointer Conventional grinding and electrical disintegration have been evaluated and compared in the context of LCA. Black-Right-Pointing-Pointer Experimental data on the leaching capacity for indium and the electricity consumption of equipment were inputted into the LCA model in order to compare the environmental performance of each method. Black-Right-Pointing-Pointer An estimate for the environmental performance was calculated as the sum of six impact categories. Black-Right-Pointing-Pointer Electrical disintegration method outperforms conventional grinding in all impact categories. - Abstract: In order to develop an effective recycling system for obsolete Liquid Crystal Displays (LCDs), which would enable both the leaching of indium (In) and the recovery of a pure glass fraction for recycling, an effective liberation or size-reduction method would be an important pre-treatment step. Therefore, in this study, two different types of liberation methods: (1) conventional grinding, and (2) electrical disintegration have been tested and evaluated in the context of Life Cycle Assessment (LCA). In other words, the above-mentioned methods were compared in order to find out the one that ensures the highest leaching capacity for indium, as well as the lowest environmental burden. One of the main findings of this study was that the electrical disintegration was the most effective liberation method, since it fully liberated the indium containing-layer, ensuring a leaching capacity of 968.5 mg-In/kg-LCD. In turn, the estimate for the environmental burden was approximately five times smaller when compared with the conventional grinding.

  1. Evaluation of different pulverisation methods for RNA extraction in squash fruit: lyophilisation, cryogenic mill and mortar grinding.

    Science.gov (United States)

    Román, Belén; González-Verdejo, Clara I; Peña, Francisco; Nadal, Salvador; Gómez, Pedro

    2012-01-01

    Quality and integrity of RNA are critical for transcription studies in plant molecular biology. In squash fruit and other high water content crops, the grinding of tissue with mortar and pestle in liquid nitrogen fails to produce a homogeneous and fine powered sample desirable to ensure a good penetration of the extraction reagent. To develop an improved pulverisation method to facilitate the homogenisation process of squash fruit tissue prior to RNA extraction without reducing quality and yield of the extracted RNA. Three methods of pulverisation, each followed by the same extraction protocol, were compared. The first approach consisted of the lyophilisation of the sample in order to remove the excess of water before grinding, the second one used a cryogenic mill and the control one a mortar grinding of frozen tissue. The quality of the isolated RNA was tested by carrying out a quantitative real time downstream amplification. In the three situations considered, mean values for A(260) /A(280) indicated minimal interference by proteins and RNA quality indicator (RQI) values were considered appropriate for quantitative real-time polymerase chain reaction (qRT-PCR) amplification. Successful qRT-PCR amplifications were obtained with cDNA isolated with the three protocols. Both apparatus can improve and facilitate the grinding step in the RNA extraction process in zucchini, resulting in isolated RNA of high quality and integrity as revealed by qRT-PCR downstream application. This is apparently the first time that a cryogenic mill has been used to prepare fruit samples for RNA extraction, thereby improving the sampling strategy because the fine powder obtained represents a homogeneous mix of the organ tissue. Copyright © 2012 John Wiley & Sons, Ltd.

  2. TENORM: Coal Combustion Residuals

    Science.gov (United States)

    Burning coal in boilers to create steam for power generation and industrial applications produces a number of combustion residuals. Naturally radioactive materials that were in the coal mostly end up in fly ash, bottom ash and boiler slag.

  3. Rapid Modelling and Grinding of Workpieces’ Inner-surface by Robot with Impedance Model Based Fuzzy Force Control Algorithm

    Directory of Open Access Journals (Sweden)

    Wang Fei

    2017-01-01

    Full Text Available To achieve rapid automatic grinding of workpieces’ inner-surface by industrial robot, a rapid translational detection strategy of workpieces’ inner-surface and fuzzy force control algorithm of grinding are proposed in this paper. The rapid translational detection strategy introduces a way to establish an inner-surface’s model quickly by recording key points of the axial section contour which reflects big curvature changes of the contour. The established model is feasible but imprecision. The force control algorithm is based on impedance model. To promote adaptability to the imprecision of the established inner-surface’s model, a fuzzy adjusting strategy is introduced in the force control algorithm. By adopting an adjusting factor, which determined by force response and a fuzzy logic, the strategy can adjust the reference trajectory of impedance model in time. Taking advantage of proposed detection and force control method, grinding experiments shows that the contact normal force maintains approximately constant, the relative mean error is within 6.5%, and the material removal thickness of the inner-surface is approximately consistent. The proposed strategy’s feasibility is verified.

  4. Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills

    Science.gov (United States)

    Raghavendra, H.; Bhat, K. L.; Udupa, K. Rajendra; Hegde, M. M. Rajath

    2011-01-01

    An attempt has been made to evaluate the suitability of austempered ductile iron (ADI) as media material for grinding iron ore in a ball mill. Spheroidal graphite (S.G) iron balls are austenitised at 900° C for 60 minutes and given stepped austempering treatment at 280° C for 30 minutes and 60 minutes followed by 380° C for 60 minutes in each case. These materials are characterised by measuring hardness, analysing X-ray diffraction (X-RD), studying microstructure using optical and scanning electron microscope (SEM). Grinding wear behaviour of these materials was assessed for wear loss in wet condition at different pH value of the mineral slurry and found that the wear rate of grinding media material decreases with increase in pH of the slurry. The wear resistance of ADI balls were compared with forged En31 steel balls and found that the stepped austempered ductile iron is superior to forged En31 steel balls.

  5. The role of tooth-grinding in the maintenance of myofascial face pain: a test of alternate models.

    Science.gov (United States)

    Janal, Malvin N; Raphael, Karen G; Klausner, Jack; Teaford, Mark

    2007-09-01

    While mechanisms of myofascial face pain are poorly understood, bruxism has been implicated in the maintenance of this painful disorder. This study evaluates whether evidence of one aspect of bruxism, tooth-grinding, is positively associated with pain severity, as predicted by a psychophysiological model, or negatively associated, as predicted by an adaptation model of face pain. Participants were 51 women who met Research Diagnostic Criteria for the myofascial subtype of temporomandibular disorder. Tooth-grinding was quantified by changes in microwear features of the molar teeth over 2 weeks. Palpated pain severity was quantified on an 11-point scale in response to palpation of the skin overlying the masseter and temporalis muscles bilaterally. Other measures included validated scales of spontaneous pain severity, stress, distress, and psychological symptoms. Association was quantified as Pearson correlation coefficients. Data showed an inverse correlation (r = -0.37, P pain severity and the index of tooth wear, supporting the adaptation model. This correlation provided a weighted average of a strong effect (r = -0.80, P pain only the right side of their face with an effect that approximated zero in those reporting bilateral pain. Tooth wear measures were negatively associated with ratings of pain severity only over the right masseter. While these data do not address the role of clenching, they cast serious doubt on the theory that myofascial face pain is maintained by tooth-grinding.

  6. The effect of grinding at various vacuum levels on the color, phenolics, and antioxidant properties of apple.

    Science.gov (United States)

    Kim, Ah-Na; Kim, Hyun-Jin; Kerr, William L; Choi, Sung-Gil

    2017-02-01

    The purpose of this study was to evaluate the effect of grinding at different vacuum levels (2.67, 6.67, 13.33, 19.99, and 101.33kPa) on key quality factors of apple. In the control apple, ground at atmospheric pressure of 101.33kPa, the antioxidant activities rapidly decreased within the first 30min, then plateaued thereafter, while enzymatic browning increased. When apples were ground and held under vacuum, changes in color and antioxidant activity were much less, and the least change was measured in samples prepared at the lowest pressure. Model fitting of the data showed that antioxidant activity decreased as a function of the logarithm of the absolute pressure. The results from analysis for key phenolic compounds including chlorogenic acid, procyanidin B2, and epicatechin indicated that these compounds were least changed at vacuum grinding at 2.67kPa, compared to atmospheric grinding. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. A novel application of α-glucosyl hesperidin for nanoparticle formation of active pharmaceutical ingredients by dry grinding.

    Science.gov (United States)

    Tozuka, Yuichi; Imono, Masaaki; Uchiyama, Hiromasa; Takeuchi, Hirofumi

    2011-11-01

    The effectiveness of α-glucosyl hesperidin (Hsp-G) as a novel grinding aid for the preparation of drug nanoparticles by dry grinding was investigated. Poorly water-soluble drugs and Hsp-G were mixed at a weight ratio of 1/5 and ground for 60 min by a vibrational ball mill. It was evident that all poorly water-soluble drugs used in this study formed nanoparticles after the ground mixtures were dispersed into distilled water. The dissolution profile of glibenclamide from the ground mixtures of glibenclamide/Hsp-G showed dramatic improvement from that of untreated drug crystals. Administration of the ground mixture of glibenclamide/Hsp-G to rats resulted in a significantly higher rate of decrease in blood glucose levels than that of untreated glibenclamide. The area above the time-curve of plasma-glucose concentrations using the ground mixture of glibenclamide/Hsp-G was 6-fold higher than that using untreated glibenclamide. The improved dissolution rate due to nanoparticle formation of glibenclamide, induced by co-grinding with Hsp-G, was responsible for this improvement.

  8. Modelling pesticides residues

    OpenAIRE

    2004-01-01

    This work is a contribution to the development of a specific method to assess the presence of residues in agricultural commodities. The following objectives are formulated: to identify and describe main processes in environment — plant exchanges, to build of a model to assess the residue concentration at harvest in agricultural commodities, to understand the functioning of the modelled system, to characterise pesticides used in field crops and identify optimisation potentials in phytosanitary...

  9. Research on controlling grinding cracks of PM pump camShaft%PM泵凸轮轴磨削裂纹控制方法的探讨

    Institute of Scientific and Technical Information of China (English)

    童景琳; 钟莉娟; 王志增

    2011-01-01

    Through analyzing the reasons causing cracking on camshaft of PM pump in grinding process, it pointed that grinding temperature, grinding stress and cooling effect are the main factors influencing grinding cracks. The experiments showed that it can reduce camshaft grinding cracks through controlling carburized layer thickness, normalizing, quenching and tempering technological parameters, and selecting high speed grinding, keeping wheel and cool liquid in good condition.%通过对PM泵凸轮轴磨削过程中产生裂纹的原因进行分析,指出磨削温度、磨削应力及冷却效果是产生磨削裂纹的主要因素.实验表明,通过控制渗碳层厚度及正火、淬火和回火工艺参数,选用高速磨削,保持良好的砂轮和冷却液状态,能够减少凸轮轴磨削裂纹.

  10. Effects of Jet Pressure on the Ground Surface Quality and CBN Wheel Wear in Grinding AISI 690 Nickel-Based Superalloy

    Science.gov (United States)

    Guitouni, Ahmed; Chaieb, Iheb; Rhouma, Amir Ben; Fredj, Nabil Ben

    2016-09-01

    Fluid application in grinding is getting attention as higher stock removal rates, higher surface integrity and longer wheel life are required. It is necessary to define proper conditions of application for meeting high productivity goals by lowering the specific grinding energy and reducing the temperature of the contact zone. The present study investigated the capacity of the jet pressure of a spot nozzle to improve the wear of a CBN wheel when grinding the AISI 690 superalloy. Grinding experiments were conducted with an emulsion-type cooling fluid delivered at pressure ranging from 0.1 to 4 MPa. Results show that the maximum stock removal, reached at 4 MPa, is 5 times the stock removal obtained at 0.1 MPa, while the grinding ratio at 4 MPa is 8 times that at 0.1 MPa, and there is a critical pressure (P c) around 1.5 MPa corresponding to the minimum specific grinding energy. Scanning electron microscopy of the grain tips showed that the wear mechanism shifts from breaking and dislodgment at low jet pressure to micro-fracture resulting in continuous self-sharpening of the abrasive grains. By lubricating at jet pressure close to P c, there is less thermal damage due to plowing and sliding and the resulting lower loading of the abrasive grains favors the micro-fracture of grains and thus a longer wheel life.

  11. Fiber Reinforced Grinding Stone Used in Ultrasonic Polishing%纤维油石在超声波抛光中的应用

    Institute of Scientific and Technical Information of China (English)

    李克华; 王振民; 王玉; 鲁涛

    2001-01-01

    Resin-bended ceramic fibre grinding is a new variety of abrasive tools in our country, widely used in ultrasonic finishing. It is suitable for precision grinding, half precision grinding, especially suitable for edge grinding, spheric and arc surface polishing of carbide or steel moulds. The selection of the shape and dimensions of the grinding stone is decided by such factors as the workpiece materials, grinding efficiency, surface finish of workpiece, abrasive grits and the coolant.%(树脂结合剂陶瓷)纤维油石是我们国家磨具的一个新品种,被广泛应用于超声波抛光中,它适合对硬质合金、钢模具进行地粗、半精磨削,尤其适用于磨削模具的边缘、曲面及圆弧面;选择纤维油石的尺寸和性能取决于工件的材质、磨削效率、工件的表面粗糙度、磨料粒度和磨削液的品种等。

  12. Effects of Jet Pressure on the Ground Surface Quality and CBN Wheel Wear in Grinding AISI 690 Nickel-Based Superalloy

    Science.gov (United States)

    Guitouni, Ahmed; Chaieb, Iheb; Rhouma, Amir Ben; Fredj, Nabil Ben

    2016-11-01

    Fluid application in grinding is getting attention as higher stock removal rates, higher surface integrity and longer wheel life are required. It is necessary to define proper conditions of application for meeting high productivity goals by lowering the specific grinding energy and reducing the temperature of the contact zone. The present study investigated the capacity of the jet pressure of a spot nozzle to improve the wear of a CBN wheel when grinding the AISI 690 superalloy. Grinding experiments were conducted with an emulsion-type cooling fluid delivered at pressure ranging from 0.1 to 4 MPa. Results show that the maximum stock removal, reached at 4 MPa, is 5 times the stock removal obtained at 0.1 MPa, while the grinding ratio at 4 MPa is 8 times that at 0.1 MPa, and there is a critical pressure ( P c) around 1.5 MPa corresponding to the minimum specific grinding energy. Scanning electron microscopy of the grain tips showed that the wear mechanism shifts from breaking and dislodgment at low jet pressure to micro-fracture resulting in continuous self-sharpening of the abrasive grains. By lubricating at jet pressure close to P c, there is less thermal damage due to plowing and sliding and the resulting lower loading of the abrasive grains favors the micro-fracture of grains and thus a longer wheel life.

  13. Fragmentation mechanism of low-grade hematite ore in a high pressure grinding roll

    Institute of Scientific and Technical Information of China (English)

    袁致涛; 李丽匣; 韩跃新; 刘磊; 刘廷

    2016-01-01

    The fragmentation mechanism of low-grade hematite ore in a high pressure grinding roll (HPGR) was studied based on the characteristics of comminuted products at different specific pressure levels. The major properties included the reduction ratio, liberation, specific surface energy, and specific surface area. The results showed that the fracture of low-grade hematite ore in HPGR was an interactive dynamic process in which the interaction between coarse particles of gangue minerals and fine particles of valuable minerals was alternately continuous with increased compactness and compacting strength of materials. Within a range of 2.8–4.4 N/mm2, valuable minerals were crushed after preferentially absorbing energy, whereas gangue minerals were not completely crushed and only acted as an energy transfer medium. Within a range of 4.4–5.2 N/mm2, gangue minerals were adequately crushed after absorbing the remaining energy, whereas preferentially crushed valuable minerals acted as an energy transfer medium. Within a range of 5.2–6.0 N/mm2 range, the low-grade hematite ore was not further comminuted because of the “size effect” on the strength of materials, and the comminution effect of materials became stable.

  14. Effect of grinding on chemical and physical properties of rice husk ash

    Institute of Scientific and Technical Information of China (English)

    Sumrerng Rukzon; Prinya Chindaprasirt; Rattana Mahachai

    2009-01-01

    The effect of grinding on the chemical and physical properties of rice husk ash was studied.Four rice husk ashes with dif-ferent finenesses, i.e.coarse original rice husk ash (RHA0), RHAI, RHA2, and RHA3 were used for the study.Ordinary Portland cement (OPC) was partially replaced with rice husk ash at 20% by weight of binder.The water to binder ratio (W/B) of the mortar was maintained at 110%±5% with flow table test.Specific gravity, fineness, chemical properties, compressive strength, and porosity test of mortars were determined.The differences in chemical composition of the rice husk ashes with different finenesses from the same batch are small.The use of RHA3 produces the mortars with good strength and low porosity.The strength of the mortar im-proves with partial replacement of RHA3 in comparison with normal coarse rice husk ash.The use of RHA3 results in a strong anddense mortar, which is due to the better dispersion and filling effect, as well as an increase in the pozzolanic reaction.

  15. Investigation of material removal in inner-jet electrochemical grinding of GH4169 alloy.

    Science.gov (United States)

    Li, Hansong; Niu, Shen; Zhang, Qingliang; Fu, Shuxing; Qu, Ningsong

    2017-06-14

    Electrochemical grinding (ECG) is a low-cost and highly efficient process for application to difficult-to-machine materials. In this process, the electrolyte supply mode directly affects machining stability and efficiency. This paper proposes a flow channel structure for an abrasive tool to be used for inner-jet ECG of GH4169 alloy. The tool is based on a dead-end tube with electrolyte outlet holes located in the sidewall. The diameter and number of outlet holes are determined through numerical simulation with the aim of achieving uniform electrolyte flow in the inter-electrode gap. Experiments show that the maximum feed rate and material removal rate are both improved by increasing the diamond grain size, applied voltage, electrolyte temperature and pressure. For a machining depth of 3 mm in a single pass, a feed rate of 2.4 mm min(-1) is achieved experimentally. At this feed rate and machining depth, a sample is produced along a feed path under computer numerical control, with the feed direction changing four times. Inner-jet ECG with the proposed abrasive tool shows good efficiency and flexibility for processing hard-to-cut metals with a large removal depth.

  16. Vacancy-type defects induced by grinding of Si wafers studied by monoenergetic positron beams

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Yoshihara, Nakaaki [Division of Applied Physics, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Mizushima, Yoriko [Devices and Materials Labs Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197 (Japan); ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Kim, Youngsuk [ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Disco Corporation, Ota, Tokyo 143-8580 (Japan); Nakamura, Tomoji [Devices and Materials Labs Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197 (Japan); Ohba, Takayuki [ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Oshima, Nagayasu; Suzuki, Ryoichi [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

    2014-10-07

    Vacancy-type defects introduced by the grinding of Czochralski-grown Si wafers were studied using monoenergetic positron beams. Measurements of Doppler broadening spectra of the annihilation radiation and the lifetime spectra of positrons showed that vacancy-type defects were introduced in the surface region (<98 nm), and the major defect species were identified as (i) relatively small vacancies incorporated in dislocations and (ii) large vacancy clusters. Annealing experiments showed that the defect concentration decreased with increasing annealing temperature in the range between 100 and 500°C. After 600–700°C annealing, the defect-rich region expanded up to about 170 nm, which was attributed to rearrangements of dislocation networks, and a resultant emission of point defects toward the inside of the sample. Above 800°C, the stability limit of those vacancies was reached and they started to disappear. After the vacancies were annealed out (900°C), oxygen-related defects were the major point defects and they were located at <25 nm.

  17. Starch grain analysis reveals function of grinding stone tools at Shangzhai site, Beijing

    Institute of Scientific and Technical Information of China (English)

    YANG XiaoYan; YU JinCheng; LI HouYuan; CUI TianXing; GUO JingNing; GE QuanSheng

    2009-01-01

    Prehistoric groundstone tools including slabs (metate, mo-pan) and mullers (mano, mo-bang) are often considered to be tools that were used to process cereals in ancient China. Most archaeologists believe that groundstone tools are indicators of an agrarian economy. This study employed starch grain analysis to examine a slab and a muller excavated from the Shangzhai Site (7500--7000 cal a BP), Beijing. Identifiable starch grains recovered from the stone tools were classified into 9 genera and 12 species, most of which were from acorns and foxtail millets. Remains from the oak species Q. mongolicus, Q. acuttssima, and Q. dentate were identified as well as a few starch grains from broomcorn (Panicum miliaseum) and bean (Vigna sp.). Other starch grains were from unidenUfiable roots and grasses. A variety of starch grains indicates that the grinding stone tools were used to process not only cereals, but also other seeds or roots that had to be ground or husked, thus bringing into question the aforementioned cereal hypothesis. Because the numbers of starch grains from nuts and millets were so large, both gathering and cultivation might have been important economic patterns before 7000 years ago in Beijing area. Moreover, the starch remains are derived from plants that indicate that the paleoclimate of Beijing was wetter and warmer than today's.

  18. Starch grain analysis reveals function of grinding stone tools at Shangzhai site, Beijing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Prehistoric groundstone tools including slabs (metate, mo-pan) and mullers (mano, mo-bang) are often considered to be tools that were used to process cereals in ancient China. Most archaeologists believe that groundstone tools are indicators of an agrarian economy. This study employed starch grain analysis to examine a slab and a muller excavated from the Shangzhai Site (7500-7000 cal a BP), Beijing. Identifiable starch grains recovered from the stone tools were classified into 9 genera and 12 species, most of which were from acorns and foxtail millets. Remains from the oak species Q. mongolicus, Q. acuttssima, and Q. dentate were identified as well as a few starch grains from broomcorn (Panicum miliaseum) and bean (Vigna sp.). Other starch grains were from unidentifiable roots and grasses. A variety of starch grains indicates that the grinding stone tools were used to process not only cereals, but also other seeds or roots that had to be ground or husked, thus bringing into question the aforementioned cereal hypothesis. Because the numbers of starch grains from nuts and millets were so large, both gathering and cultivation might have been important economic patterns before 7000 years ago in Beijing area. Moreover, the starch remains are derived from plants that indicate that the paleoclimate of Beijing was wetter and warmer than today’s.

  19. Sintering of new SiC-Phosphate composite materials for grinding wheels fabrication

    Directory of Open Access Journals (Sweden)

    Silva, R. F.

    2004-04-01

    Full Text Available The effect of several variables such as molar ratio P2O5/B2O3 (X, temperature and heating cycle on the strength of chemically bonded SiC materials for grinding wheels fabrication was studied. It was shown that the highest compressive strength (52.4 MPa could be obtained using an optimal molar ratio X = 4.5 and a multiple step heating cycle up to a sintering temperature of 800oC. DTA, XRD, SEM and dilatometrical analysis were performed to follow the different stages of the structural development.

    Se estudia el efecto de diferentes variables tales como la razón molar P2O5/B2O3(X, temperatura y ciclo de calentamieno sobre la resistencia de materiales de SiC aglomerados quimicamente para la fabricación de muelas arasivas. Se ha comprobado que la más alta resistencia a la compresión (52,4MPa pueda obtenerse usando una razón molar òptima x= 4,5 y un ciclo de calentamiento en múltiples etapas hasta la temperatura de 800º C. Estudios mediante ATD, DRX, MEB y análisis dilatométricos fueron llevados a cabo para seguir las diferentes etapas del desarrollo microestructura.

  20. Repair weld induced residual stresses in thick-walled steel pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Smith, G.C.; Holz, P.P.

    1978-06-01

    If a flaw requiring corrective action were to be found in an operating nuclear pressure vessel, there would be considerable safety and economic implications. Should such a flaw be found, one possible corrective action would be an in situ repair weld. A repair of this type would presumably involve grinding away material in a region encompassing the flaw and then filling the resulting cavity with weld metal. Thermal stress relieving under those conditions could lead to serious difficulties associated with thermal expansion and warpage and would therefore most likely be avoided. Such a departure from normal procedure raises questions relating to residual stresses and material toughness levels which would have to be assessed before a repair could be recommended or approved. The residual stress measurements reported are intended to provide baseline information to aid in an assessment should such a repair ever have to be seriously considered.

  1. Reduction of Residual Stresses in Sapphire Cover Glass Induced by Mechanical Polishing and Laser Chamfering Through Etching

    Directory of Open Access Journals (Sweden)

    Shih-Jeh Wu

    2016-10-01

    Full Text Available Sapphire is a hard and anti-scratch material commonly used as cover glass of mobile devices such as watches and mobile phones. A mechanical polishing using diamond slurry is usually necessary to create mirror surface. Additional chamfering at the edge is sometimes needed by mechanical grinding. These processes induce residual stresses and the mechanical strength of the sapphire work piece is impaired. In this study wet etching by phosphate acid process is applied to relief the induced stress in a 1” diameter sapphire cover glass. The sapphire is polished before the edge is chamfered by a picosecond laser. Residual stresses are measured by laser curvature method at different stages of machining. The results show that the wet etching process effectively relief the stress and the laser machining does not incur serious residual stress.

  2. Covariant Residual Entropy

    CERN Document Server

    Hubeny, Veronika E

    2014-01-01

    A recently explored interesting quantity in AdS/CFT, dubbed 'residual entropy', characterizes the amount of collective ignorance associated with either boundary observers restricted to finite time duration, or bulk observers who lack access to a certain spacetime region. However, the previously-proposed expression for this quantity involving variation of boundary entanglement entropy (subsequently renamed to 'differential entropy') works only in a severely restrictive context. We explain the key limitations, arguing that in general, differential entropy does not correspond to residual entropy. Given that the concept of residual entropy as collective ignorance transcends these limitations, we identify two correspondingly robust, covariantly-defined constructs: a 'strip wedge' associated with boundary observers and a 'rim wedge' associated with bulk observers. These causal sets are well-defined in arbitrary time-dependent asymptotically AdS spacetimes in any number of dimensions. We discuss their relation, spec...

  3. Effect of working position on vertical motion straightness of open hydrostatic guideways in grinding machine

    Science.gov (United States)

    Zha, Jun; Wang, Zhiwei; Xue, Fei; Chen, Yaolong

    2016-08-01

    Hydrostatic guideways have various applications in precision machine tools due to their high motion accuracy. The analysis of motion straightness in hydrostatic guideways is generally ignoring the external load on the slider. A variation force also exists, caused by the different working positions, together with the dead load of the slider and that of other auxiliary devices. The effect of working position on vertical motion straightness is investigated based on the equivalent static model, considering the error averaging effort of pressured oil film in open hydrostatic guideways. Open hydrostatic guideways in LGF1000 are analyzed with this approach. The theoretical results show that the slider has maximum vertical motion straightness when the working position is closer the guiderail of Y axis. The vertical motion straightness reaches a minimum value as the working position is located at the center of the two guiderails on the Y axis. The difference between the maximum and minimum vertical motion straightness is 34.7%. The smaller vertical motion straightness is attributed to the smaller spacing of the two pads centers, along the Y direction. The experimental results show that the vertical motion straightness is 4.15 μm/1200 mm, when the working position is located in the middle of the X beam, and 5.08 μm/1200 mm, when the working position is approaching the Y guiderails, denoting an increase of 18.3%. The changing trends of the measured results validate the correctness of the theoretical model. The research work can be used to reveal the variation law of accuracy of the open hydrostatic guideways, under different working positions, to predict the machining precision, and provides the basis for an error compensation strategy for gantry type grinding machines.

  4. Panoptikumas utilitarizmo principais grindžiamoje visuomenėje: komunikaciniai aspektai

    Directory of Open Access Journals (Sweden)

    Jovilė Barevičiūtė

    2012-04-01

    Full Text Available Straipsnis skirtas britų filosofo Jeremy’o Benthamo Panoptikumo projekto teorinių pagrindų analizei ir interpretacijai. Siekiant ištirti šio projekto kilmę ir tikslus, pirmoje straipsnio dalyje susitelkiama ties jo autoriaus, kaip utilitarizmo etinės doktrinos propaguotojo, socialine pozicija. Teigiama, kad panoptikumas, kaip universali socialinė institucija, yra neatsiejamas nuo utilitarizmo principų, sudarančių jo atsiradimo pagrindą. Antroje straipsnio dalyje aptariami svarbiausi utilitarizmo principais grindžiamos visuomenės komunikaciniai aspektai, komunikaciją suprantant kaip socialinę sąveiką ir socialinius veiksmus. Panoptikumo projektas traktuojamas kaip priemonė pasiekti ir užtikrinti sėkmingą visuomenės narių komunikaciją, išryškinant ne tik stipriąsias, bet ir silpnąsias jo puses. Trečioje straipsnio dalyje iškeliamas esminis šio tyrimo klausimas – ar šis projektas atliepia, ar prieštarauja utilitarizmo principams? Komunikaciniu aspektu pateikiamas dvejopas šio panoptikumo projekto vertinimas. Viena vertus, šis socialinės institucijos modelis pasmerkia potencialius jos narius nekomunikacijai ir dezinformacijai. Kita vertus, XVIII a. fizinių bausmių klestėjimo epochos sąlygomis iškyla kaip pažangi ir humaniškumą aukštinanti idėja.

  5. Optimization on manufacturing and testing technology for rectangle aperture off-axis aspheric mirror fine grinding

    Science.gov (United States)

    Chen, Xi; Guo, Peiji; Wang, Dongdong

    2016-10-01

    High precision aspheric surface can be obtained conveniently by using single point diamond turning technology, liquidmagnetic polishing technology and ion beam polishing technology, but the costs of manufacturing is too enormous to be widely used. In fact, in the field of optical processing, the most commonly used technical solution is still making a best fit sphere firstly compared with aspheric equation, and then remove the material on the glass to correct the error between aspheric and best fit sphere by precision grinding and precision polishing. The resolving of the best-fit sphere and the material removal, however, is a very important problem during the fabrications. The two dimensional maps of surface error between the best fit sphere and the corresponding aspheric surface shows W shaped which has the maximum removal at the center and the edge of the workpeace and gradually reduces to zero at the 70.7 percent of the diameter. In the process of deterministic optical manufacturing, the edge effect will arise because of the change of machining conditions when polishing tool locates in edge area, which will lower the surface accuracy of workpiece and debase machining efficiency. W shaped error distribution and the edge effect will make it difficult to remove the error on the edge of the workpiece. Aiming at the situation, an algorithm available for control of edge effect is proposed. Considering the requirement of minimum material removal and the control of edge effect, the radius of the anti-edge effect sphere is calculated by programming. The advantage of the algorithm is shown by the comparison of results derived from new algorithm and empirical equation. At the same time, the application in the off-axis asphere fabrications also proves the correctness of the algorithm. This algorithm is very helpful for the theory and practice of the fabrications of off-axis asphere.

  6. Using magnetic seeds to improve the aggregation and precipitation of nanoparticles from backside grinding wastewater.

    Science.gov (United States)

    Wan, Terng-Jou; Shen, Shu-Min; Siao, Sheng-Han; Huang, Chong-Fu; Cheng, Chiung-Yi

    2011-12-01

    Backside grinding (BG) wastewater treatment typically requires large quantities of chemicals, i.e. polyaluminum chloride (PAC) coagulant and produces considerable amounts of sludge, increasing the loading and cost of subsequent sludge treatment and disposal processes. This study investigated the effects of the addition of magnetic seeds (FeO*Fe(2)O(3)) of selected particle sizes and of optimized combinations of magnetic seeds and PAC on the aggregation of silica nanoparticles from BG wastewater and on the sedimentation time at various pH values. The results show that the turbidity of BG wastewater was significantly reduced by the magnetic aggregation treatment. The dosage of PAC combined with 2.49gL(-1) or 1.24gL(-1) of magnetic seeds was reduced by 83% (from 60 to 10mgL(-1)) compared to the conventional process of using only PAC as a coagulant. The turbidity of the BG wastewater, initially 1900-2500NTU, could also be successfully decreased about to 23NTU by the addition of 3.74gL(-1) magnetite (FeO*Fe(2)O(3)) only at pH 5 with an applied magnetic field of 1000G. Different coagulation conditions using magnetic seeds combined with coagulant resulted in different aggregation performances. The treatment performance was more effective by using two-stage dosing, in which magnetic seeds and PAC were added separately, than that with one-stage dosing, where the magnetic seeds and PAC were added simultaneously during rapid mixing. The two-stage dosing allowed for a reduction in the optimum dosage of magnetic seeds from 3.74gL(-1) to 2.49gL(-1) or 1.24gL(-1) without affecting performance when coupled with 0.01gL(-1) of PAC coagulant. The developed method effectively reduced the production of waste sludge.

  7. Effect of working position on vertical motion straightness of open hydrostatic guideways in grinding machine

    Science.gov (United States)

    Zha, Jun; Wang, Zhiwei; Xue, Fei; Chen, Yaolong

    2017-01-01

    Hydrostatic guideways have various applications in precision machine tools due to their high motion accuracy. The analysis of motion straightness in hydrostatic guideways is generally ignoring the external load on the slider. A variation force also exists, caused by the different working positions, together with the dead load of the slider and that of other auxiliary devices. The effect of working position on vertical motion straightness is investigated based on the equivalent static model, considering the error averaging effort of pressured oil film in open hydrostatic guideways. Open hydrostatic guideways in LGF1000 are analyzed with this approach. The theoretical results show that the slider has maximum vertical motion straightness when the working position is closer the guiderail of Y axis. The vertical motion straightness reaches a minimum value as the working position is located at the center of the two guiderails on the Y axis. The difference between the maximum and minimum vertical motion straightness is 34.7%. The smaller vertical motion straightness is attributed to the smaller spacing of the two pads centers, along the Y direction. The experimental results show that the vertical motion straightness is 4.15 μm/1200 mm, when the working position is located in the middle of the X beam, and 5.08 μm/1200 mm, when the working position is approaching the Y guiderails, denoting an increase of 18.3%. The changing trends of the measured results validate the correctness of the theoretical model. The research work can be used to reveal the variation law of accuracy of the open hydrostatic guideways, under different working positions, to predict the machining precision, and provides the basis for an error compensation strategy for gantry type grinding machines.

  8. THE INFLUENCE OF JOINT GRINDING OF CEMENT AND COOPER SLAG ON MORTAR PROPERTIES

    Directory of Open Access Journals (Sweden)

    Kravtsov Aleksey Vladimirovich

    2016-08-01

    Full Text Available The problem of applying copper manufacturing waste locating in the Chelyabinsk region as a component of mixed is considered in this article. Application of mixed binder with superplasticizers, based on esters with carboxyl groups, have not sufficiently been studied by the present time due to the diversity of species and complexity of the chemical structure. This trend is current for today’s science because of the growing rates and scales of building production, in particular, of concrete works. Copper slag dumps located in the Ural Federal district haven’t been widely used in building production or in other industrial production by the present time. Efficient utilization of copper production waste materials will help to solve ecological problems in many regions of Russia. Structure formation period of cement stone based on mixed binder made of Portland cement and granulated cooper slag with application of superplasticizer is studied in the article. The authors present a thermal variation diagram of mortar based on mixed binder made of Portland cement and granulated cooper slag in the process of 21 hours of hardening under normal conditions and the results of ultrasound investigation of concrete structure formation period during 5 hours of hardening. The strength development process diagram of mortar based on mixed binder made of Portland cement and granulated cooper slag for 28 days of hardening under normal conditions and the research results of the compressive strength of concrete samples are shown in this article. The obtained characteristics don’t confirm the prospects of applying joint grinding for mortar with the observed kind of non-ferrous metallurgy waste. Also, the obtained results allow us to make a conclusion about little advantages of using this method of binder production. Copper slag can be more effectively used as a component of complex organic and mineral admixture for building production with different purposes and fields

  9. Residual-stress measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ezeilo, A.N.; Webster, G.A. [Imperial College, London (United Kingdom); Webster, P.J. [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  10. Decomposition of residue currents

    OpenAIRE

    Andersson, Mats; Wulcan, Elizabeth

    2007-01-01

    Given a submodule $J\\subset \\mathcal O_0^{\\oplus r}$ and a free resolution of $J$ one can define a certain vector valued residue current whose annihilator is $J$. We make a decomposition of the current with respect to Ass$(J)$ that correspond to a primary decomposition of $J$. As a tool we introduce a class of currents that includes usual residue and principal value currents; in particular these currents admit a certain type of restriction to analytic varieties and more generally to construct...

  11. Sharing Residual Liability

    DEFF Research Database (Denmark)

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    Economic models of tort law evaluate the efficiency of liability rules in terms of care and activity levels. A liability regime is optimal when it creates incentives to maximize the value of risky activities net of accident and precaution costs. The allocation of primary and residual liability...... allows policy makers to induce parties to undertake socially desirable care and activity levels. Traditionally, tort law systems have assigned residual liability either entirely on the tortfeasor or entirely on the victim. In this paper, we unpack the cheapest-cost-avoider principle to consider...

  12. 凹面轮廓凸轮轴成形磨削工艺研究%Research on profile grinding process of concave camshaft

    Institute of Scientific and Technical Information of China (English)

    邓朝晖; 彭欢欢; 万林林; 粟福喻; 黄强

    2014-01-01

    By analyzing the difficulties about the concave contour of camshaft in CNC grinding ,a new grinding process that the concave camshaft is machined by two grinding wheels of different diameters was proposed .A calculation formula about the small wheel radius is given ,and calculating the minimum radius of curvature of the concave contour can help us decide whether it need to switch the grinding wheel .Analyzes in detail the profile grinding process with large size and small size grinding wheels .Be-sides,some experiments are also carried out on the CNC 8325B ultra high speed camshaft grinder .The experimental results show that the concave contour grinding of camshaft can be achieved by this new process and meet the machining accuracy require -ments.%分析带有凹面轮廓的凸轮轴(简称凹面凸轮轴)数控磨削加工难点,提出采用大砂轮与小砂轮复合数控成形磨削凹面凸轮轴新工艺。给出了小砂轮半径的计算公式,通过计算凹面轮廓的最小曲率半径,对比判断是否需要切换砂轮。详细分析了大砂轮与小砂轮复合数控成形磨削凹面凸轮轴新工艺过程,并在CNC8325B全数控凸轮轴超高速复合磨床上进行了高速磨削加工实验,实验结果表明,该工艺方法可以实现凹面凸轮轴轮廓的磨削成形加工,满足了加工精度要求。

  13. Online, efficient and precision laser profiling of bronze-bonded diamond grinding wheels based on a single-layer deep-cutting intermittent feeding method

    Science.gov (United States)

    Deng, Hui; Chen, Genyu; He, Jie; Zhou, Cong; Du, Han; Wang, Yanyi

    2016-06-01

    In this study, an online, efficient and precision laser profiling approach that is based on a single-layer deep-cutting intermittent feeding method is described. The effects of the laser cutting depth and the track-overlap ratio of the laser cutting on the efficiency, precision and quality of laser profiling were investigated. Experiments on the online profiling of bronze-bonded diamond grinding wheels were performed using a pulsed fiber laser. The results demonstrate that an increase in the laser cutting depth caused an increase in the material removal efficiency during the laser profiling process. However, the maximum laser profiling efficiency was only achieved when the laser cutting depth was equivalent to the initial surface contour error of the grinding wheel. In addition, the selection of relatively high track-overlap ratios of laser cutting for the profiling of grinding wheels was beneficial with respect to the increase in the precision of laser profiling, whereas the efficiency and quality of the laser profiling were not affected by the change in the track-overlap ratio. After optimized process parameters were employed for online laser profiling, the circular run-out error and the parallelism error of the grinding wheel surface decreased from 83.1 μm and 324.6 μm to 11.3 μm and 3.5 μm, respectively. The surface contour precision of the grinding wheel significantly improved. The highest surface contour precision for grinding wheels of the same type that can be theoretically achieved after laser profiling is completely dependent on the peak power density of the laser. The higher the laser peak power density is, the higher the surface contour precision of the grinding wheel after profiling.

  14. 砂轮修整对成形磨齿齿廓偏差的补偿%Compensation for Tooth Profile Deviations of Form-grinding Tooth with Grinding Wheel Dressing

    Institute of Scientific and Technical Information of China (English)

    汪中厚; 耿直; 李刚; 朱文敏

    2015-01-01

    To enhance the accuracy of gear profile grinding,a compensation method for gear profile deviations by grinding wheel dressing is studied.Firstly,the necessity of studying this method is illustrated,and then the principle of this method is introduced.The tooth profile measurement data is fitted by 3 B spline curve,the fitting curve equation and the real tooth surface equation are founded.Based on it,in view of the tooth profile deviation compensation,the imaginary tooth surface equation used to calculate the grinding wheel cross-sectional shape is proposed.Based on the different gear measurement data of the same tooth,the different grinding wheel cross-sectional shape can be got,therefore all the grinding wheel cross-sectional shape can form line group,then using least square method to fit the discrete points in line group,the best grinding wheel cross-sectional shape can be got to compensate the tooth profile deviation.Finally,the experiment result shows that the tooth profile deviations could be enhanced to accuracy grade 3 from 5,the tooth profile slope deviation and tooth profile shape deviation are reduced obviously.%为了提高成形磨齿齿轮的精度,研究了一种通过修整砂轮廓形来补偿齿廓偏差的方法.首先说明了研究此方法的必要性,然后介绍了此方法的原理:用三次B样条曲线对齿形测量数据点进行拟合,求出拟合后的曲线方程,并在此基础上建立了真实的齿面方程求解模型,提出了针对齿廓偏差补偿的用于计算砂轮截形的假想齿面方程.基于同一个齿轮不同齿的测量数据,可得到不同的砂轮截形,为此将所有的砂轮截形组成线族,对线族中的离散点采用最小二乘法进行拟合,拟合之后的砂轮截形为补偿齿廓偏差的最佳截形.最后,通过实验试磨分析,加工出的齿轮经测量齿廓偏差由5级精度提高到了3级精度,并且同时补偿了齿廓倾斜偏差与齿廓形状偏差.

  15. Designing with residual materials

    NARCIS (Netherlands)

    Walhout, W.; Wever, R.; Blom, E.; Addink-Dölle, L.; Tempelman, E.

    2013-01-01

    Many entrepreneurial businesses have attempted to create value based on the residual material streams of third parties. Based on ‘waste’ materials they designed products, around which they built their company. Such activities have the potential to yield sustainable products. Many of such companies

  16. Sharing Residual Liability

    DEFF Research Database (Denmark)

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    allows policy makers to induce parties to undertake socially desirable care and activity levels. Traditionally, tort law systems have assigned residual liability either entirely on the tortfeasor or entirely on the victim. In this paper, we unpack the cheapest-cost-avoider principle to consider...

  17. Residual stresses within sprayed coatings

    Institute of Scientific and Technical Information of China (English)

    JIANG Yi; XU Bin-shi; WANG Hai-dou

    2005-01-01

    Some important developments of residual stress researches for coating-based systems were studied. The following topics were included the sources of residual stresses in coatings: error analysis of Stoney's equation in the curvature method used for the measurement of coating residual stress, the modeling of residual stress and some analytical models for predicting the residual stresses in coatings. These topics should provide some important insights for the fail-safe design of the coating-based systems.

  18. Hydrogen Storage and Release Properties of Transition Metal-Added Magnesium Hydride Alloy Fabricated by Grinding in a Hydrogen Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Sung Nam; Song, Myoung Youp [Chonbuk National University, Jeonju (Korea, Republic of); Park, Hye Ryoung [Chonnam National University, Gwangju (Korea, Republic of)

    2016-07-15

    90 wt% MgH{sub 2}+5 wt% Ni+2.5 wt% Fe+2.5 wt% Ti (called MgH{sub 2}+Ni+Fe+Ti), a hydrogen storage and release material, was fabricated by grinding in a hydrogen atmosphere, and then its quantities of stored and released hydrogen as a function of time were examined. A nanocrystalline MgH{sub 2}+Ni+Fe+Ti specimen was made by grinding in a hydrogen atmosphere and subsequent hydrogen storage-release cycling. The crystallite size of Mg and the strain of the Mg crystallite after ten hydrogen storage-release cycles, which were obtained using the Williamson-Hall method, were 38.6 (±1.4) nm and 0.025 (±0.0081) %, respectively. The MgH{sub 2}+Ni+Fe+Ti sample after the process of grinding in a hydrogen atmosphere was highly reactive with hydrogen. The sample exhibited an available storage capacity of hydrogen (the amount of hydrogen stored during 60 minutes) of about 5.7 wt%. At the first cycle, the MgH2+Ni+Fe+Ti sample stored hydrogen of 5.53 wt% in 5 minutes, 5.66 wt% in 10 minutes and 5.73 wt% in 60 minutes at 573 K and 12 bar of hydrogen. The MgH{sub 2}+Ni+Fe+Ti after activation released hydrogen of 0.56 wt% in 5 minutes, 1.26 wt% in 10 minutes, 2.64 wt% in 20 minutes, 3.82 wt% in 30 minutes, and 5.03 wt% in 60 minutes.

  19. 一种装配式凸轮轴磨削工艺方案%Assembling Camshaft Grinding Process Solution

    Institute of Scientific and Technical Information of China (English)

    黄雷明

    2015-01-01

    The camshaft, as one of engine gas distribution system''s important component, is always in the running state when the engine is running, for opening and closing air valve. The manufacturing quality, directly affects the engine power, fuel economy and emissions targets, etc. Assembled camshaft as a new type of camshaft, represents a trend of application of automobile engine camshaft. Grinding process is the key process of the camshaft machining process; the camshaft grinding quality is directly related to the final product quality. An assembled camshaft grinding process technique and application are introduced.%凸轮轴作为发动机配气系统的重要组成部件之一,在发动机工作时,始终处于运转状态,用于控制气门的开启和闭合.其制造质量好坏,直接影响到发动机的动力性、排放指标、燃油经济性等.装配式凸轮轴作为一种新型的凸轮轴,代表了汽车发动机凸轮轴的一种应用趋势.磨削工序是凸轮轴加工过程中的关键工序,磨削质量直接关系到凸轮轴的最终产品质量,介绍了一种装配式凸轮轴的磨削加工工艺方案及其应用.

  20. Influence of blanching and grinding process with hot water on beany and non-beany flavor in soymilk.

    Science.gov (United States)

    Lv, Yan-Chun; Song, Huan-Lu; Li, Xin; Wu, Liang; Guo, Shun-Tang

    2011-01-01

    A total of 8 beany odor-active compounds and 4 non-beany aroma-active compounds of traditional soymilk were identified through dynamic headspace dilution analysis (DHDA) and gas chromatography-olfactometry-mass spectrometry (GC-O-MS). To eliminate the beany flavors, soymilk was processed with hot water blanching and grinding for 2, 4, 6, 8, and 10 min with a temperature between 80 and 100 °C. A total of 5 beany odor-active compounds and 3 non-beany aroma-active compounds of this soymilk were analyzed by headspace solid phase microextraction (HS-SPME). As a result, lipoxygenase (LOX) activity gradually decreased by hot water treatment with time, and with the decrease of Lox activity, the 5 beany odor-active compounds and 3 non-beany aroma-active compounds were significantly decreased. However, the reduction in non-beany flavor compounds was smaller than for beany odor compounds. Therefore, a balance between beany and non-beany flavors can be reached in soymilk. When the soaked soybeans were blanched and ground with hot water for 2 to 6 min, the LOX activity was between 38% and 57% of the beginning activity. For these processing times, the non-beany compounds could be largely maintained. The ratio of the total peak area of the 3 non-beany aroma compounds and 5 beany flavor compounds was between 0.07 and 0.12, and the sensory scores of the aromas were higher than that of the off-flavors. Practical Application: Beany flavors in soymilk could be reduced with hot water blanching and grinding at temperature above 80 °C. However, the treatment of hot water blanching affected the non-beany aromas of soymilk. A suitable blanching and grinding time is necessary to achieve a balance of soymilk flavors.

  1. 水泥助磨剂在水泥粉磨中的重要作用%Important Roles of Grinding Aid in the Manufacture of Cement

    Institute of Scientific and Technical Information of China (English)

    王建兵; 覃爱苗; 巫朝剑; 刘荣进; 陈平

    2012-01-01

    水泥助磨剂可以很好地改善粉磨条件、提高粉磨效率、大大降低粉磨能耗,同时还具有优化水泥颗粒级配、增加水泥的抗压抗折强度、减少温室气体的排放、提高水泥中混合材的掺量等优点.系统阐述了助磨剂在水泥粉磨中的重要作用,包括助磨剂的作用机理、分类、所带来的经济效益、发展历程以及存在的问题等.%The utilizing of grinding aids in the manufacture of cement can improve grinding condition, increase grinding efficiency, reduce production cost and energy consumption. It can also make a contribution in particle-size distribution and compressive strength, greenhouse gases emission reduction, increasing admixtures into cement products and so on. The important roles of grinding aid in the cement grinding are reviewed, including mechanism, classification, economic benefit, development history, existing problems,etc.

  2. Enhancement of the dissolution rate and gastrointestinal absorption of pranlukast as a model poorly water-soluble drug by grinding with gelatin.

    Science.gov (United States)

    Chono, Sumio; Takeda, Eri; Seki, Toshinobu; Morimoto, Kazuhiro

    2008-01-22

    The effect of grinding with gelatin on the dissolution behavior and gastrointestinal absorption of a poorly water-soluble drug was evaluated using the antiasthmatic agent, pranlukast, as a model poorly water-soluble drug. A ground pranlukast-gelatin mixture was prepared by grinding equal quantities of pranlukast and gelatin. In the dissolution testing, the dissolution rate of pranlukast in the suspension of the ground pranlukast-gelatin mixture under conditions of pH 3.0, 5.0 and 7.0 was markedly faster than that in the suspension of pranlukast. According to powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC) analysis, the enhanced dissolution rate of pranlukast produced by grinding with gelatin was caused by changing the crystalline state of pranlukast into an amorphous state. In an animal experiment, the bioavailability of pranlukast following oral administration of the ground pranlukast-gelatin mixture to rats was threefold greater than that following administration of pranlukast. In the in vitro permeation experiment, the amount of permeated pranlukast through Caco-2 cell monolayers after application of the ground pranlukast-gelatin mixture was greater than that after application of pranlukast. These results suggest that the enhancement of the gastrointestinal absorption of pranlukast by grinding with gelatin is due to enhancement of the dissolution rate. Grinding a poorly water-soluble drug with gelatin is a useful method of enhancing its gastrointestinal absorption.

  3. Influence of diamond wheel grinding process on surface micro-topography and properties of SiO2/SiO2 composite

    Science.gov (United States)

    Cao, Xiaoyan; Lin, Bin; Wang, Yan; Wang, Shaolei

    2014-02-01

    According to anisotropic and inhomogeneous structure of fiber-reinforced ceramic matrix composites (FRCMC), it is difficult to control the surface quality with the traditional method used in metal material. The present paper studies the influence of diamond wheel grinding process on surface micro-topography and properties of SiO2/SiO2 composite. The research is based on some new discovery that the material enhanced fiber orientations play a key role in micro-topography of FRCMC grinding surface. Through a series of experiments, we investigate the relationship between grinding process and the quality of composites surface. We also analyze characteristics of the material surface topography height, wave distribution and surface support properties in details. This paper employs the orthogonal design to optimize grinding process parameters and also successfully models a critical condition to modify the surface characteristics. The results show that speed of grinding wheel has the greatest influence on height and surface support properties, the next is grain mesh size and depth of cut. The grain mesh size is the key factor for surface micro-topography modification. Compared to the surface with woven texture, the modified surface has better symmetrical characteristic. The research obtained will be an important technical support on improving the processing quality of FRCMC.

  4. EXPERIMENTAL AND MICRO-IMPACT MECHANISM OF GRINDING HEAD IN POLISHING MACHINE%抛光机磨头微观冲击机理与实验

    Institute of Scientific and Technical Information of China (English)

    邵俊鹏; 徐斌

    2012-01-01

    In order to investigate the microcosmic polishing mechanism ot grlnclmg neaa. Micro impact Mechanism of low/ high speed grinding head were derived. Mathematical modeling of microimpact and amplitude is established. It is concluded that the process of forming ceramic tile defects, by a series of SEM experiments of ceramic tiles. It is concluded that the micro-impact mechanism theory agreement with ceramic tile surface topography is obtained. A series of vibration experiments of grinding head is performed, low speed grinding head can help ceramic tile defects and it can considerably reduce the impact vibration of grinding head at the rough polishing; high speed grinding head so as to effectively enhance the tile surface smoothness at the finish polishing.%为了研究磨头微观加工机理,提出低、高速磨头微观冲击机理。建立微观冲击速度和振幅模型。通过SEM实验得出瓷砖微观缺陷形成过程,并验证了冲击机理理论符合瓷砖表面形貌。通过振动实验得出:粗抛阶段,低速磨头可以减少瓷砖缺陷,降低冲击振动;精抛阶段,高转速磨头可以提高瓷砖的表面质量。

  5. Investigation of efficient synthesis of 1, 8-dioxo-octahydroxanthene derivatives under solvent-free grinding method

    Directory of Open Access Journals (Sweden)

    R. Borah

    2013-10-01

    Full Text Available In these studies, we had observed polyaniline (PANI supported p-toluene sulfonic acid (TsOH and FeCl3 (PANI- TsOH, PANI-FeCl3 as excellent reusable solid acid catalysts for the synthesis of 1, 8-dioxo-octahydroxanthene derivatives 4(a-g under solvent-free grinding method at mild conditions. Additionally, in the same optimized condition ferric nitrate nonahydrate also acted as (non-reusable very reactive inexpensive Lewis acid catalyst. The ferric nitrate nonahydrate lost its activity in the form of Clayfen (Clay-supported ferric nitrate catalyst.

  6. RESEARCH ON MODELING AND CHARACTERISTICS OF THE SPINDLE DYNAMIC COUPLING ABSORBERING SYSTEM OF A SUPER-PRECISION SURFACE GRINDING MACHINE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The bearing is described by constrain matrix, and the spindle system of a NC surface grinding machine is simplified as elastic-coupling beam, then modal synthesis method is used to establish the dynamic model of beam.Moreover, the response of the end of rotor is analyzed, and the natural frequency, principle mode and other dynamic characteristics of the coupling system are studied, the law of bearing stiffness to coupling frequency and amplitude of rotor is also found.Finally, according to the actual condition, a dynamic absorber is designed.The simulation and experimental results show that the amplitude of spindle can be declined effectively when the dynamic absorber is attached.

  7. Influence of clinker grinding-aids on the intrinsic characteristics of cements and on the behaviour of mortars

    Directory of Open Access Journals (Sweden)

    Fernández Luco, L.

    2003-12-01

    Full Text Available In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrete. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portland cement clinker and gypsum. A control cement mix was also produced without using any admixture and the results are shown on a comparative basis. Conclusions indicate that grinding-aids additives have some influence on the characteristics of portland cement produced, increasing their specific surface and modifying microstructure and its packing ability. Mortars and concretes made with cements ground with the addition of gringing-aids exhibit higher strength at any age and a reduced water demand. Special attention should be taken to consider any interaction with water-reducing admixture in concretes and mortars.

    En la fabricación de cemento portland es una práctica creciente la utilización de aditivos para optimizar el proceso de molienda; éstos quedan incorporados en el producto final y pueden influir sobre las características y propiedades del cemento, morteros y hormigones. En este trabajo se presenta la evaluación de dos aditivos comerciales en la molienda conjunta de clínker de cemento portland y yeso comercial, tratados en un molino a bolas a escala de laboratorio, en forma comparativa con un cemento sin aditivo producido en forma equivalente. Las conclusiones indican que los aditivos de molienda tienen influencia en las características del cemento resultante, incrementando su superficie y modificando su microestructura y estado de agregación; los morteros mejoran sus prestaciones mecánicas a todas las edades y se reduce la demanda de agua

  8. Residual compressive surface stress increases the bending strength of dental zirconia.

    Science.gov (United States)

    Inokoshi, Masanao; Zhang, Fei; Vanmeensel, Kim; De Munck, Jan; Minakuchi, Shunsuke; Naert, Ignace; Vleugels, Jozef; Van Meerbeek, Bart

    2017-04-01

    To assess the influence of surface treatment and thermal annealing on the four-point bending strength of two ground dental zirconia grades. Fully-sintered zirconia specimens (4.0×3.0×45.0mm(3)) of Y-TZP zirconia (LAVA Plus, 3M ESPE) and Y-TZP/Al2O3 zirconia (ZirTough, Kuraray Noritake) were subjected to four surface treatments: (1) 'GROUND': all surfaces were ground with a diamond-coated grinding wheel on a grinding machine; (2) 'GROUND+HEAT': (1) followed by annealing at 1100°C for 30min; (3) 'GROUND+Al2O3 SANDBLASTED': (1) followed by sandblasting using Al2O3; (4) 'GROUND+CoJet SANDBLASTED': (1) followed by tribochemical silica (CoJet) sandblasting. Micro-Raman spectroscopy was used to assess the zirconia-phase composition and potentially induced residual stress. The four-point bending strength was measured using a universal material-testing machine. Weibull analysis revealed a substantially higher Weibull modulus and slightly higher characteristic strength for ZirTough (Kuraray Noritake) than for LAVA Plus (3M ESPE). For both zirconia grades, the 'GROUND' zirconia had the lowest Weibull modulus in combination with a high characteristic strength. Sandblasting hardly changed the bending strength but substantially increased the Weibull modulus of the ground zirconia, whereas a thermal treatment increased the Weibull modulus of both zirconia grades but resulted in a significantly lower bending strength. Micro-Raman analysis revealed a higher residual compressive surface stress that correlated with an increased bending strength. Residual compressive surface stress increased the bending strength of dental zirconia. Thermal annealing substantially reduced the bending strength but increased the consistency (reliability) of 'GROUND' zirconia. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  9. Effect of grinding intensity and feed physical form on in vitro adhesion of Salmonella Typhimurium and mannose residues in intestinal mucus receptors for salmonellae.

    Science.gov (United States)

    Callies, A; Sander, S J; Verspohl, J; Beineke, A; Kamphues, J

    2012-12-01

    The hypothesis of this study was that feeding a fine, pelleted diet (FP) compared to a coarse meal diet (CM) results in a higher mannose content in the intestinal mucus of pigs and therefore an increased in vitro adhesion of Salmonella Typhimurium DT104 L to the mucus. The 2 diets were fed to a total of 24 weaned pigs for 6 wk after which mannose content in the mucus was evaluated histochemically using the α1-3-d-mannose-specific lectin Galanthus nivalis agglutinin. The crypt width was determined as an indirect measure for the amount of secreted mucus. Ileal and cecal tissue samples were incubated with approximately 7.77 × 10(7) cfu Salmonella Typhimurium and numbers of salmonellae adhering to the mucus and/or mucosa were determined by culture techniques. There was no effect of feed physical form on the in vitro adhesion of S. Typhimurium either in the ileum (7.1 ± 0.19 log(10) cfu/g tissue) or in the cecum (6.8 ± 0.26 log(10) cfu/g). The mannose content of the mucus also did not differ between the treatment groups. The crypts of the duodenum, jejunum, and cecum were wider (P < 0.05) after feeding the CM diet. This might be an indication for a higher mucus production in these pigs.

  10. Observer's observables. Residual diffeomorphisms

    CERN Document Server

    Duch, Paweł; Świeżewski, Jedrzej

    2016-01-01

    We investigate the fate of diffeomorphisms when the radial gauge is imposed in canonical general relativity. As shown elsewhere, the radial gauge is closely related to the observer's observables. These observables are invariant under a large subgroup of diffeomorphisms which results in their usefulness for canonical general relativity. There are, however, some diffeomorphisms, called residual diffeomorphisms, which might be "observed" by the observer as they do not preserve her observables. The present paper is devoted to the analysis of these diffeomorphisms in the case of the spatial and spacetime radial gauges. Although the residual diffeomorphisms do not form a subgroup of all diffeomorphisms, we show that their induced action in the phase space does form a group. We find the generators of the induced transformations and compute the structure functions of the algebras they form. The obtained algebras are deformations of the algebra of the Euclidean group and the algebra of the Poincar\\'e group in the spat...

  11. Residual contaminants in milk

    Directory of Open Access Journals (Sweden)

    Nevijo Zdolec

    2006-07-01

    Full Text Available Various chemical agents are used during the whole production chain of milk and dairy products. Production of feedingstuffs is accompanied with pesticide usage, which may remain in environment, thus are transported through feeding into animals, animal products and finally in human organism. Preparation procedure and storage conditions of feed also influence on milk safety in the sense of mycotoxins entering into the food chain. Chemical agents are, on daily basis, used on dairy farms either as detergents or disinfections. The residuals of cleaning agents might remain in milk if the cleaning agents and its dosage are not performed adequately. Besides already mentioned agents, a great influence in milk production can bee seen through veterinary drugs usage, particularly antibacterial drugs (mastitis. Proper application of drugs and by following legal recommendation, a by-reactions can be avoided such as allergic reaction in humans, development of resisting bacteria or even undesirable influence on starter cultures in dairy products manufacture. The maximum residue limits, monitoring plan as well as sampling procedures are set up within the harmonization of Croatian and European legislation, in order to provide official control of residues in foodstuffs of animal origin.

  12. EXPLOITATIVE DESTRUCTION FEATURES FOR DETONATION ULTRADISPERSED DIAMONDS OF INITIAL METALLIC PROTECTION FOR ABRASIVE POWDER GRAINS TO DIAMOND-SPARK GRINDING TOOLS

    Directory of Open Access Journals (Sweden)

    Yury GUTSALENKO

    2015-05-01

    Full Text Available The problem of exploitation of diamond grinding wheels with metal coating for their grains including detonation ultra-dispersed diamonds to increase functional reliability to maintain the initial integrity of grains in the pressing and sintering of diamond-metal composites in the tool production is considered. One problem is that the presence of detonation ultra-dispersed diamonds in the grain metal coating of diamond powders not only improves the coating functional reliability in protection from destruction in the subsequent pressing and sintering in the production tool, but also resistance of such coating to the opening of the diamond cutting basis of the grains on the grinding wheel working surface that come into working contact with the material being processed. An analysis of the features of an effective exploitative destruction of detonation ultra-dispersed diamonds in the metal coating using electric current in the tool of the diamondspark grinding processes is presented.

  13. Effect of Grinding Process on The Wafer Surface Roughness%磨削工艺对晶片表面粗糙度的影响

    Institute of Scientific and Technical Information of China (English)

    张文斌; 王仲康

    2015-01-01

    The grinding process directly affects the surface quality of silicon wafer quality param eters, am ong these param eters,surface roughness is one of the im portant index in differential geom etry param eters of the silicon wafer quality. Effect of grinding wheel type,the wheel infeed rate grinding process on the wafer surface roughness are analyzed.%磨削工艺直接影响着磨削后晶片的参数,在这些参数中,表面粗糙度是鉴别晶片几何参数好坏的重要指标之一。分析了磨削工艺中砂轮粒度、砂轮进给速度对表面粗糙度的影响。

  14. Research Status and Development of Green Grinding Technology%绿色磨削加工技术研究现状及进展

    Institute of Scientific and Technical Information of China (English)

    霍文国; 徐九华; 傅玉灿; 戚厚军

    2011-01-01

    This paper reports new technology investigation of green grinding and grinding process. The traditional grinding process often uses the flood delivery coolant to lower the temperature in the grinding zone; but a lot of use of grinding fluid does great harm to environments and workers, and increases its cost of recycle. The thesis analyzes applications and technical characters of green grinding process such as dry cutting, minimum quantity lubricant, liquid nitrogen cooling, air eject cooling, inner cooling and solid lubrication cooling in machining. At last, we draw a conclusion that the green cutting process technology will gradually replace the conventional flood form. It is a developing direction for future manufacture and has a good outlook.%传统的磨削加工大量采用磨削液浇注法降低加工区温度,磨削液的大量使用给环境和操作者健康带来了很大危害,而且增加了磨削液排放回收的成本.本文分析了绿色磨削加工技术,如干磨削技术、微量润滑、液氮冷却、低温气体冷却、高压射流冷却、内冷却和固体润滑冷却技术在机械制造中的应用及其技术特征.绿色磨削加工技术将逐渐取代传统的浇注供液方法,是未来制造业的发展方向,具有很好的发展前景.

  15. Coagulation settling characteristics and eliminating pollution analysis of fine-grind natural zeolite in static and turbulent flow.

    Science.gov (United States)

    Zhu, Ruirui; Zhu, Jianzhong; Chen, Liang

    2014-05-01

    The phenomenon of coagulation settling in liquid suspensions has a variety of applications, including mineral processing, treatment of industrial effluents, and municipal sewage sludge purification. This study was to investigate the coagulation settling characteristics of fine-grind natural zeolite and evaluate the removal efficiency of contaminants simultaneously in static and turbulent flow. A series of column experiments were conducted to pattern the characteristics of spatial and temporal variation of coagulation settling and removal contaminants in static and turbulent flow. The results indicated that the suspended solid concentration presented an apparent exponential decay with coagulation settling time in static flow (R (2)  > 0.99), coagulation settling rate of the fine zeolite-suspended solid in static flow was between 0.005 and 0.05 cm/s obtained from the repeat depth suction method. The relation between average C/C 0 of pollutants and suspended solid concentration was exponential before the settlement for 24 h and that was the line after the settlement for 24 h. Several various models were presented to highlight the coagulation settling characteristics of fine-grind natural zeolite in static and turbulent flow. Compared to hydrostatic settling experiments, zeolite-suspended solid presented better removal efficiency of pollutants and greater removal rate of pollutants in turbulent flow.

  16. Effect of grinding process on the level of leachability of the contaminants from the fly ashes from combustion of biomass

    Directory of Open Access Journals (Sweden)

    Pawluk Aleksandra

    2016-01-01

    Full Text Available The most commonly used renewable energy source in Polish energy production companies is solid biomass which is used both as a separate fuel or as a component co-incinerated together with (mostly hard coal. During its incineration the biomass generates by-products with diverse and variable physicochemical properties. The most of the waste from production of electricity and/or heat are fly ashes. The fly ashes from combustion of biomass are a particular kind of waste distinguished by high level of leaching of contaminants and variable chemical composition. The by-products from combustion can only be used in production when their physicochemical properties meet specific parameters. This article presents results of research on leachability of chemical pollutants from dry ashes of combustion or co-combustion of biomass. The study of the impact of grinding of ashes on the level of their leachability was also conducted. Ashes from combustion of biomass as well as their mixture with fluidized ash from combustion of charcoal were submitted to grinding process. Afterwards level of leachability was measured on them to determine prospect of utility in mining technologies.

  17. Naturally occurring diacetyl and 2,3-pentanedione concentrations associated with roasting and grinding unflavored coffee beans in a commercial setting

    Directory of Open Access Journals (Sweden)

    Shannon H. Gaffney

    2015-01-01

    Full Text Available Over the last decade, concerns have been raised about potential respiratory health effects associated with occupational exposure to the flavoring additives diacetyl and 2,3-pentanedione. Both of these diketones are also natural components of many foods and beverages, including roasted coffee. To date, there are no published studies characterizing workplace exposures to these diketones during commercial roasting and grinding of unflavored coffee beans. In this study, we measured naturally occurring diacetyl, 2,3-pentanedione, and respirable dust at a facility that roasts and grinds coffee beans with no added flavoring agents. Sampling was conducted over the course of three roasting batches and three grinding batches at varying distances from a commercial roaster and grinder. The three batches consisted of lightly roasted soft beans, lightly roasted hard beans, and dark roasted hard beans. Roasting occurred for 37 to 41 min, and the grinding process took between 8 and 11 min. Diacetyl, 2,3-pentanedione, and respirable dust concentrations measured during roasting ranged from less than the limit of detection (grinding, diacetyl, 2,3-pentanedione, and respirable dust concentrations ranged from 0.018 to 0.39 ppm, 0.0089 to 0.21 ppm, and grinding were higher than those measured during roasting. During grinding, concentrations decreased with increased distance from the source. Measured concentrations of both diketones were higher during grinding of soft beans than hard beans. The results indicate that airborne concentrations of naturally occurring diacetyl and 2,3-pentanedione associated with unflavored coffee processing: (1 are similar to the concentrations that have been measured in food flavoring facilities; (2 are likely to exceed some

  18. Experimental Investigation on Effect of Grinding Direction on Wear Under Heavy Load and Slow Speed Conditions with Molybdenum Disulphide (MoS2 as Additive in Commercial Lubricant

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    S. M. Muzakkir

    2015-03-01

    Full Text Available In the present work, experimental investigation has been carried out to identify the effect of grinding direction on the wear of the sliding surfaces subjected to heavy load and low sliding velocity with molybdenum disulphide MoS2 as additive in commercial lubricant. The conformal block and disk test setup has been used to conduct experiments on conformal blocks with two grinding directions: one along the direction of sliding and other across the direction of sliding. The wear of the block is measured as its weight loss after the test. The results of the experiments are reported.

  19. Characteristics of gas and residues produced from electric arc pyrolysis of waste lubricating oil.

    Science.gov (United States)

    Song, Geum-Ju; Seo, Yong-Chil; Pudasainee, Deepak; Kim, In-Tae

    2010-07-01

    An attempt has been made to recover high-calorific fuel gas and useful carbonaceous residue by the electric arc pyrolysis of waste lubricating oil. The characteristics of gas and residues produced from electric arc pyrolysis of waste lubricating oil were investigated in this study. The produced gas was mainly composed of hydrogen (35-40%), acetylene (13-20%), ethylene (3-4%) and other hydrocarbons, whereas the concentration of CO was very low. Calorific values of gas ranged from 11,000 to 13,000 kcal kg(-1) and the concentrations of toxic gases, such as NO(x), HCl and HF, were below the regulatory emissions limit. Gas chromatography-mass spectrometry (GC/MS) analysis of liquid-phase residues showed that high molecular-weight hydrocarbons in waste lubricating oil were pyrolyzed into low molecular-weight hydrocarbons and hydrogen. Dehydrogenation was found to be the main pyrolysis mechanism due to the high reaction temperature induced by electric arc. The average particle size of soot as carbonaceous residue was about 10 microm. The carbon content and heavy metals in soot were above 60% and below 0.01 ppm, respectively. The utilization of soot as industrial material resources such as carbon black seems to be feasible after refining and grinding.

  20. Establishing Mathematical Model and Calculating Principle of Number Control Grinding with"Three Variations"for spiral Guiding Wheel%"三变"螺旋导轮数控磨削原理

    Institute of Scientific and Technical Information of China (English)

    吴行飞

    2000-01-01

    The establishment of mathematical model and its calculation principle for number control grinding of spiral guiding wheel with"three variations"(diameter variation,screw pitch variation and tooth type angle variation)are expatiated,the calculating method which is necessary to number control programe is provided for the number control grinding of this new type spiral guiding wheel.