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Sample records for roll mill grinding

  1. The implementation of HPGR mills in existing grinding circuits

    Energy Technology Data Exchange (ETDEWEB)

    Patzelt, N.; Knecht, J.; Longhurst, D. [Krupp Polysius AG, Beckum (Germany)

    1996-12-31

    High pressure grinding mills have been successfully introduced in the industry. They offer the possibilities for capacity increase of existing plants and reduction of operating costs. The plants in operation are running in different applications and modes of operation. They can be installed in a combination with SAG and ball mills or in a stand-alone mode. In combination with other grinding mills, it has to be investigated how the HPGR can be installed to reach the full efficiency. This paper describes the possibilities of implementing high pressure grinding rolls and shows by case studies the potential of savings which could be reached.

  2. NUMERICAL EVALUATION OF TEMPERATURE DISTRIBUTION IN THE ROLLING MILL ROLLS

    Directory of Open Access Journals (Sweden)

    José Claudino de Lira Júnior

    2013-06-01

    Full Text Available In hot rolling processes occur changes in the profile of the rolling mill rolls (expansion and contraction and constant wear due to mechanical stress and continuous thermal cycles of heating/cooling caused by contact rolled material- working roll and the cooling system by water jets in their surface, decreasing their lifetime. This paper presents a computational model to simulate the thermal performance of rolling mill rolls. The model was developed using the finite volume method for a transient two-dimensional system and allows calculating the temperature distribution of the rolling mill rolls under various conditions of service. Here it is investigated the influence of flow rate and temperature of the cooling water on the temperature distribution. The results show that the water temperature has greater influence than the water flow to control the surface temperature of the cylinders.

  3. Ultrafine grinding of muscovite in close packed media mill

    Energy Technology Data Exchange (ETDEWEB)

    Orumwense, O.A.; Forssberg, E. (Division of Mineral Processing, Luleaa University of Technology, Luleaa (SE))

    1990-01-01

    This paper presents the results of batch vibration milling of mica. Grinding time or energy input, and solid and dispersant concentrations were the variables. Product fineness is greatly influenced by energy input, solid concentration, and mill settings. Muscovite can be ground efficiently to a high degree of fineness at a relatively high energy expenditure. Particle shape is preserved or improved presumably due to the predominance of exfoliation as opposed to true fracture as the mode of particle breakage. (author).

  4. Breakage parameters for ultrafine grinding in stirred-media mills

    Energy Technology Data Exchange (ETDEWEB)

    Cho, H.; Hogg, R. [Pennsylvania State Univ., University Park, PA (United States)

    1995-12-31

    Ultrafine grinding into the micron and sub-micron size range is becoming increasingly important for a wide range of industries involving ceramics, chemicals, paints, coating, pharmaceuticals, coal and others. Investigations of long-time grinding of fine quartz (to about 80% passing 0.35 {micro}m) in a 0.6 liter stirred-media mill are described. Breakage rates and primary breakage distributions have been determined based on extensive characterization of the ground products by laser scatterings diffraction and gas adsorption. The results indicate that, while there is qualitative similarity between the breakage parameters for ultrafine and conventional (coarse) grinding, there are important, quantitative differences. In particular, it is found that primary breakage distributions become significantly narrower in the submicron sizes. The trend can be described using double-truncated log-normal distributions in which both a maximum (breaking) size and a grind limit are specified. The breakage distributions become progressively narrower as the size being broken becomes finer. Breakage rates follow a typical, consistent pattern in which the rate decreases with size according to a simple power law. Further decrease in the rates seems to occur after very long grinding times when the entire mill contents become finer than about 1 {micro}m. The effect is explained as a result of changes in the rate/size relationship in the submicron range.

  5. High pressure grinding rolls (HPGR) applications in the cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Aydogan, N.A.; Ergun, L.; Benzer, H. [Hacettepe University, Ankara (Turkey). Mining Engineering Dept.

    2006-02-15

    In this study, the performance evaluation studies in five cement grinding circuits, in which HPGR is used in various configurations, were presented. Sampling surveys were performed around the circuits followed by the determination of the size distribution of the samples down to 1.8 {mu}m using a combination of sieving and laser sizing methods. The results showed that the specific energy consumption of the circuit decreases as the size reduction achieved by the HPGR increases. As given in the case studies when the size reduction ratio (F{sub 80}/P{sub 80}) changed from 308.2 to 4.4, the specific energy consumption of the HPGR was 8.02 and 4.05 kWh/ton, respectively. Since various configurations offer rather different ball mill feeds, the best usage of HPGR could be attained by optimization of operating parameters of both ball mills and air classifiers. (author)

  6. 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 agglomerationsmay occur during grinding of soft minerals, like gypsum, especially at lower and higher air pressures, respectively.

  7. Feasibility of utilizing a fluid energy mill in the grinding of potassium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Collins, L.W.

    1977-09-28

    The feasibility of utilizing the fluid energy mill for grinding potassium perchlorate for use in pyrotechnic blends was investigated. It was found that the particle size of the material was significantly reduced by the action of the mill with no significant change in the level of contamination. The grinding parameters selected seemed to have no direct relationship with the physical properties of the final product. The action of the mill induced a significant electrostatic charge on the potassium perchlorate which affects the handling characteristics and possibly the chemical character. The feasibility but not the desirability of utilizing the fluid energy mill to grind potassium perchlorate was demonstrated.

  8. The effect of grinding media performance on milling and operational behaviour

    Scientific Electronic Library Online (English)

    U., Weber; D., Langlois.

    2010-03-01

    Full Text Available The effect of grinding media performance on milling and operational behaviour was demonstrated under different selected conditions of calcium carbonate slurry milling. A variety of grinding media materials and bead sizes, along with two different stirrer tip speeds, were used in the grinding process [...] to generate a particle size reduction of the calcium carbonate (CaCO3). To determine the optimum milling parameters the collected test data were used to calculate and evaluate specific energy as well as stress intensity under different milling conditions.

  9. Numerical simulation of grinding phenomena in ball media mills and its applications; Baitai mirunai no funsei gensho no suchi shimyureshon to sono oyo

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Toyokazu [Hosokawa Micron Corp., Osaka (Japan)

    1999-10-01

    For efficient grinding, it is necessary to choose appropriate mill among many types of machines according to feedstocks, their grain size and requested grain size for products. For fine grinding of high hardness ceramics, generally jet mill, roller mill and ball media mill are applied. Effects of milling machine and grinding condition on the force added to particles from media in the media mill are examined, and relationship between grinding process and grinding rate is explained. Movement simulation of ball in media mill by discrete element method, relationship among media collision, grinding rate and grinding condition, and change of media flow by setting condition were illustrated. (NEDO)

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

    OpenAIRE

    Farzaneh Ahmadzadeh; Jan.Lundberg

    2013-01-01

    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 decis...

  11. Metallurgical analysis of spalled work roll of hot strip mill

    International Nuclear Information System (INIS)

    In this study failure analysis of four work roll of the Hot Strip Mill is carried out. The microstructure is correlated with the chemical composition of shell and roll-life. It was concluded that for the longer service of the roll, cementite, graphite and martensite should be balanced (as per working requirement of the mill). (author)

  12. Continuous grinding kinetics of ethenzamide particles by fluidized-bed jet-milling.

    Science.gov (United States)

    Fukunaka, T; Golman, B; Shinohara, K

    2006-03-01

    Continuous grinding kinetics of Ethenzamide powder, as a model active pharmaceutical ingredient (API) was investigated by fluidized-bed jet-milling. Because the oversize fractions after the classification were well fitted by a modified Rosin-Rammler distribution function, an equation of grade efficiency curve was obtained, which was also characteristic of API. A continuous grinding model was developed on the basis of a batch model by using 1st Kapur function relating grinding rate, the grade efficiency curve, and the overall process flow model consisting of grinding, classification, and mixing zones. The residual ratio obtained was well fitted to the experimental results except for the particle size range smaller than 4 microm and larger than 100 microm. Furthermore, because the volume of the active grinding zone adopted as the fitting parameter was found to be 5 cm3 in all experiments and the value was considered to be appropriate dimensionally, this result supports the reliability of the model. PMID:16556539

  13. Radiotracer Investigation of Clinker Grinding Mills for Cement Production at Ghacem

    OpenAIRE

    Ishmael Iddisah Mumuni; C.P.K. Dagadu, K.A. Danso, P.S. Adu, H.A. Affum, I. Lawson, G.K. Appiah, A. Coleman and M.A. Addo

    2011-01-01

    Radiotracer Residence Time Distribution (RTD ) method was used to investigate the process of clinker grinding in Ghana Cement Plant (GHACEM) at Tema with the objective of determining hold-up and grinding efficiencies of two ball mills operating in close circuit regime. The experiment was conducted using 40Ci Au-198 radiotracer in liquid state and highly sensitive NaI detectors for radiation measurement. The experimental RTD data revealed that the Mean Residence Times (MRT) of the material in ...

  14. Optimum condition determination of Rirang uranium ores grinding using ball mill

    International Nuclear Information System (INIS)

    The grinding experiment on Rirang Uranium ore has been carried out with the aim is to find out the optimum condition of wet grinding using ball mill to produce particle size -325, -200 and -100 mesh. This will be used for decomposition feed the test was done by examine the parameters comparison of ore's weight against ball's weight and time of grinding. The test shown that the product of particle size -325 meshes was achieved optimum condition at the comparison ore's weight: ball = 1:3, grinding time 150 minutes, % solid 60, speed rotation of ball mill 60 rpm and recovery of grinding was 93.51 % of -325 mesh. The product of particle size -200 mesh was achieved optimum condition at comparison ore's weight: ball = 1:2, time of grinding 60 minutes, the fraction of + 200 mesh was regrind, the recovery of grinding 6.82% at particle size of (-200 + 250) mesh, 5.75 % at (-250 + 325)m mesh and, 47.93 % -325 mesh. The product of particle size -100 mesh was achieved the optimum condition at comparison ore's weight: ball = 1:2, time of grinding at 30 minutes particle size +100 mesh regrinding using mortar grinder, recovery of grinding 30.10% at particle size (-100 + 150) m, 12.28 % at (-150 + 200) mesh, 15.92 % at (-200 + 250) mesh, 12.44 % at (-250 + 325) mesh and 29.26 % -325 mesh. The determination of specific gravity of Rirang uranium ore was between 4.15 - 4.55 g/cm3

  15. Structural causes of defects in a cast iron mill roll

    OpenAIRE

    Krawczyk, J.

    2008-01-01

    This paper describes an analysis of a defective microstructure of a mill roll. For this purpose, a piece of a broken roll was collected. That roll was made of mottled cast iron. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed nearby the fracture in the roll. Observations were conducted on polished sections, first not etched, and then etched, which allowed us to trace carefull...

  16. Structural causes of defects in a cast iron mill roll

    Directory of Open Access Journals (Sweden)

    J. Krawczyk

    2008-07-01

    Full Text Available This paper describes an analysis of a defective microstructure of a mill roll. For this purpose, a piece of a broken roll was collected. That roll was made of mottled cast iron. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed nearby the fracture in the roll. Observations were conducted on polished sections, first not etched, and then etched, which allowed us to trace carefully the propagation of the fracture. There was found a strict correlation between the microstructure of the roll and the progress occurring in the crack. It was ascertained that the basic reason for the damage to the roll was banded precipitations of ledeburitic cementite. In addition, cementite formed a continuous network. Another microstructure defects of that roll are also precipitations of secondary carbides on the boundaries of former grain of austenite as well as the occurrence of upper bainite in its matrix. The results obtained hereunder allow broadening the data base relative to the genesis of damages to mill rolls, which in future will permit one to design a proper microstructure of cast iron mill rolls. Proper microstructure of cast iron mill roll should be shaped at the stage of designing the chemical composition, conditions of crystallization or heat treatment if any.

  17. Grinding media wear during mechanical alloying of Ni-W alloys in a spex mill

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, T.H.; Wang, Z. (Virginia Univ., Charlottesville, VA (United States))

    1992-09-15

    Mechanical alloying (MA) is utilized for producing powdered materials having intriguing properties and structures. Some of these materials manifest extended solid solubility. Mechanical alloying has also been used to synthesize equilibrium and nonequilibrium intermediate (or intermetallic) phases, amorphous materials and inorganic nonmetallics. In their laboratory the authors have been studying the amorphization of Ni-W alloys, accomplished by extended grinding in a SPEX mill. It was brought to The authors' attention (by the reviewer of a manuscript ) that perhaps the authors ought to be paying some attention to the effect of wear debris on the tendency for, and extent of, the amorphization the authors observed. This paper reports on the contamination that accompanies SPEX milling of No-W alloys. The authors will show that wear debris, while only a small fraction of the total grinding media charge, is sufficient to alter appreciably the composition of the milled powder.

  18. 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.

  19. Dry, fine grinding of dolomite with the Sala Agitated Mill SAM 7.5 - effects of grinding media and grinding additive; Trockene Feinstmahlung von Dolomit mit der Ruehrwerkskugelmuehle SAM 7.5 - Einfluss von Mahlkoerper und Mahlhilfsmittel

    Energy Technology Data Exchange (ETDEWEB)

    Forssberg, E. [Technische Univ. Luleaa (Sweden). Inst. fuer Aufbereitung; Wang, Y. [Technische Univ. Luleaa (Sweden). Inst. fuer Aufbereitung; Persson, H. [Technische Univ. Luleaa (Sweden). Inst. fuer Aufbereitung

    1995-05-01

    The effects of grinding media and grinding additives on such a grinding process with this mill have been investigated in some detail. It was indicated that 8 mm x 8 mm cylpebs were favourable for the grinding performance, as compared with 8 mm balls. Experimental results have shown that the smaller grinding media (4 mm balls) gave the better transfer of energy from the media to the material to be ground compared to the larger 8 mm balls and 8 mm x 8 mm cylpebs. Use of amine for dry grinding of dolomite only had a significant effect when the fine fractions built up in the mill. The reduction in energy consumption by the grinding additive might be due to adsorption of amine on the fine particles by influencing the mass transport within the mill. (orig.) [Deutsch] Mit dieser Muehle wurde der Einfluss von Mahlkoerpern und Mahlhilfsmitteln bei diesem Mahlverfahren untersucht. Dabei hat sich gezeigt, dass 8 mm x 8 mm-Cylpebs guenstiger fuer das Mahlverhalten sind als 8 mm-Kugeln. Gegenueber den groesseren 8 mm-Kugeln und den 8 mm x 8 mm-Cylpebs uebertragen die kleineren Mahlkoerper (4 mm-Kugeln) die Mahlkoerperenergie besser auf das Mahlgut. Der Einsatz von Aminen zur Trockenmahlung von Dolomit hatte nur dann einen wesentlichen Einfluss, wenn sich Feinstkorn in der Muehle bildete. Die Reduzierung des Energieverbrauches durch das Mahlhilfsmittel ist eventuell eine Folge der Adsorption von Aminen auf das Feinstkorn, das den Massentransport innerhalb der Muehle beeinflusst. (orig.)

  20. Behavior of grinding media in sand mill (I)

    Energy Technology Data Exchange (ETDEWEB)

    Gondo, Toyohiko; To, Michiharu; Murakami, Yasuhiro (Kurume College of Technology, Fukuoka (Japan); Kyushu Univ., Fukuoka (Japan))

    1989-04-20

    Crushing or dispersion by a media in a sand mill is regarded to be carried out by the collision and shearing among the media, although its mechanism has seldom been examined. In this study, a two-dimensional model of a vertical disc type mill was trial made to be equipped with a concentric disc or with an eccentric disc which were observed using a video camera to measure the flow pattern and the velocity distribution of the media as well as its self rotation. In the concentric disc, the media showed a movement and at speed roughly in the tangential direction; self rotation of the media occurred at the end of the disc and its vicinity. Direction of the self rotation was mainly in the tangential direction in the horizontal section, and in the vertical direction to it. In the case of an eccentric disc, the movement and the direction of the media were not only tangentially, but also in the radial direction. As a conclusion, the eccentric disc mill is effective for crushing, dispersion and mixing of a sand mill as it moves the media in various directions. 4 refs., 11 figs., 1 tab.

  1. Effect of filling degree of grinding media on motion of media particle and grinding characteristics in horizontal type sand mill; Yokogata sand mill no ryudo kyodo to funsai tokusei ni oyobosu media ryushi no jutenritsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Teshiba, T.; Takao, M.; Komori, S.; Murakami, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Yoshida, H. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1996-07-10

    The effect of filled ratio on flow characteristics of grinding media was investigated for a horizontal type sand mill, in which the internal blade and external cylinder counter rotated independently. The relationship between flow characteristics anal grinding performance was discussed by carrying out grinding tests of calcium carbonate. As a result, it was found that the grinding characteristics obtained for both rotation methods can be well correlated as a function of intensity of velocity fluctuations weighted by appearance frequency and the second power of filled ratio, where the reciprocal collision probability of media particles is taken into consideration. 6 refs., 2 tabs.

  2. Particle Characterisation and Grinding Behaviour of Gamma-Alumina Slurries Prepared in a Stirred Media Mill

    OpenAIRE

    Stephen Adegbite

    2012-01-01

    This paper investigates gamma-alumina slurry preparation in a stirred media mill to develop protocols for the characterisation of slurries for coating onto monolithic catalyst supports. The relationship between the pH and the zeta potential of particles is determined. The gamma–alumina particles are found to be optimally stabilised at a pH of 4 and zeta potential of +41 mV. The grinding behaviour of gamma-alumina particles inside the mill is determined in terms of the number of stress events...

  3. Effect of media size in stirred ball mill grinding of coal

    Energy Technology Data Exchange (ETDEWEB)

    Mankosa, M.J.; Adel, G.T.; Yoon, R.H.

    1986-12-01

    As a prerequisite to producing super-clean coal with any physical coal-cleaning process, such as microbubble flotation, the feed coal must be micronized to liberate finely disseminated mineral matter. The stirred ball mill is regarded as one of the most efficient devices for micronizing coal. Using a 13.4 cm batch mill, the optimum operating conditions have been determined in terms of media size, feed size and media type. The rate of breakage determined with monosized feeds are compared on the basis of specific energy consumption. It has been found that a 20:1 ball size/particle size ratio gives optimum grinding conditions.

  4. Dependence of rates of breakage on fines content in wet ball mill grinding

    Science.gov (United States)

    Bhattacharyya, Anirban

    The following research fundamentally deals with the cause and implications of nonlinearities in breakage rates of materials in wet grinding systems. The innate dependence of such nonlinearities on fines content and the milling environment during wet grinding operations is also tested and observed. Preferential breakage of coarser size fractions as compared to the finer size fractions in a particle population were observed and discussed. The classification action of the pulp was deemed to be the probable cause for such a peculiarity. Ores with varying degrees of hardness and brittleness were used for wet grinding experiments, primarily to test the variations in specific breakage rates as a function of varying hardness. For this research, limestone, quartzite, and gold ore were used. The degree of hardness is of the order of: limestone, quartzite, gold ore. Selection and breakage function parameters were determined in the course of this research. Functional forms of these expressions were used to compare experimentally derived parameter estimates. Force-fitting of parameters was not done in order to examine the realtime behavior of particle populations in wet grinding systems. Breakage functions were established as being invariant with respect to such operating variables like ball load, mill speed, particle load, and particle size distribution of the mill. It was also determined that specific selection functions were inherently dependent on the particle size distribution in wet grinding systems. Also, they were consistent with inputs of specific energy, according to grind time. Nonlinearity trends were observed for 1st order specific selection functions which illustrated variations in breakage rates with incremental inputs of grind time and specific energy. A mean particle size called the fulcrum was noted below which the nonlinearities in the breakage trends were observed. This magnitude of the fulcrum value varied with percent solids and slurry filling, indicating that breakage rates were being influenced by the milling environment as a whole. Primarily, there was always an increase in the breakage rates of coarser fractions with an increase in the amount of fines in the particle population. Consequently, the breakage rates of the finer size fractions were observed to decrease with an increase in grind time. Similar trends were noticed for 2nd order specific selection functions, where incremental inputs of specific energy were provided to observe realtime trends in the nonlinearity of breakage rates closely. Although the breakage rates for coarser size fractions increase with an increase in the amount of fines, the nature of nonlinearities varied with extended grind times. 1st order and 2nd order energy-specific breakage rates were observed to notice the variation in trends with extended grind times. Implications of such nonlinearities in specific breakage rates of various materials were tested on predictive simulation techniques, using the normalized linear population balance model and compared with an incremental methodology of specific energy input.

  5. Aplicação de prensas de rolos em minério de ferro High pressure grinding rolls for iron ore

    Directory of Open Access Journals (Sweden)

    Farley Santos Ribeiro

    2010-06-01

    Full Text Available O Projeto Minas-Rio, de propriedade da Anglo Ferrous Brazil, prevê a utilização de prensa de rolos para cominuição do undersize do peneiramento (-25,4 mm. Esta é uma aplicação que se torna cada dia mais comum, porém relativamente nova em minério de ferro. Foram realizados estudos no Centro de Pesquisa da Krupp/Polysius na Alemanha, com o objetivo de validar a aplicação de prensa de rolos para minério de ferro, de determinar os principais parâmetros usados no dimensionamento e de avaliar o impacto do aumento da umidade da alimentação na capacidade específica e na distribuição granulométrica do produto. Os excelentes resultados obtidos, nos ensaios em escala-piloto, somados aos ganhos financeiros da aquisição e operação, à maior estabilidade do processo diante variações de w i (work index e à distribuição granulométrica da alimentação, contribuíram para aprovar, de forma irrestrita, a aplicação de prensa de rolos para cominuição de minério de ferro no Projeto Minas-Rio.The Minas-Rio Project that is being implemented by Anglo Ferrous Brazil, foresees the use of HPGR (High Pressure Grinding Rolls to grind the undersize from screening at (-25.4 mm. This application is recent for iron ore comminuting. The study described herein, took place at the Krupp/Polysius Research Center, in Germany, aiming to validate the HPGR application for iron ore, as well as to determine the main parameters used in equipment sizing. The study also aimed to assesses the impact of moisture variation on ore feed in respect to specific grinding capacity and product size distribution. The great results obtained from the sample tests that demonstrated more process stability for the work index (w i and granulometric feed distribution variations, together with the possible financial gains from the HPGR implementation, contributed to the unrestricted approval of the HPGR application for iron ore comminuting in the Minas-Rio Project.

  6. Aplicação de prensas de rolos em minério de ferro / High pressure grinding rolls for iron ore

    Scientific Electronic Library Online (English)

    Farley Santos, Ribeiro; José Francisco Cabello, Russo; Thiago, Costa.

    2010-06-01

    Full Text Available O Projeto Minas-Rio, de propriedade da Anglo Ferrous Brazil, prevê a utilização de prensa de rolos para cominuição do undersize do peneiramento (-25,4 mm). Esta é uma aplicação que se torna cada dia mais comum, porém relativamente nova em minério de ferro. Foram realizados estudos no Centro de Pesqu [...] isa da Krupp/Polysius na Alemanha, com o objetivo de validar a aplicação de prensa de rolos para minério de ferro, de determinar os principais parâmetros usados no dimensionamento e de avaliar o impacto do aumento da umidade da alimentação na capacidade específica e na distribuição granulométrica do produto. Os excelentes resultados obtidos, nos ensaios em escala-piloto, somados aos ganhos financeiros da aquisição e operação, à maior estabilidade do processo diante variações de w i (work index) e à distribuição granulométrica da alimentação, contribuíram para aprovar, de forma irrestrita, a aplicação de prensa de rolos para cominuição de minério de ferro no Projeto Minas-Rio. Abstract in english The Minas-Rio Project that is being implemented by Anglo Ferrous Brazil, foresees the use of HPGR (High Pressure Grinding Rolls) to grind the undersize from screening at (-25.4 mm). This application is recent for iron ore comminuting. The study described herein, took place at the Krupp/Polysius Rese [...] arch Center, in Germany, aiming to validate the HPGR application for iron ore, as well as to determine the main parameters used in equipment sizing. The study also aimed to assesses the impact of moisture variation on ore feed in respect to specific grinding capacity and product size distribution. The great results obtained from the sample tests that demonstrated more process stability for the work index (w i) and granulometric feed distribution variations, together with the possible financial gains from the HPGR implementation, contributed to the unrestricted approval of the HPGR application for iron ore comminuting in the Minas-Rio Project.

  7. Grinding energy and physical properties of chopped and hammer-milled barley, wheat, oat, and canola straws

    Energy Technology Data Exchange (ETDEWEB)

    J.S. Tumuluru; L.G. Tabil; Y. Song; K.L. Iroba; V. Meda

    2014-01-01

    In the present study, specific energy for grinding and physical properties of wheat, canola, oat and barley straw grinds were investigated. The initial moisture content of the straw was about 0.13–0.15 (fraction total mass basis). Particle size reduction experiments were conducted in two stages: (1) a chopper without a screen, and (2) a hammer mill using three screen sizes (19.05, 25.4, and 31.75 mm). The lowest grinding energy (1.96 and 2.91 kWh t-1) was recorded for canola straw using a chopper and hammer mill with 19.05-mm screen size, whereas the highest (3.15 and 8.05 kWh t-1) was recorded for barley and oat straws. The physical properties (geometric mean particle diameter, bulk, tapped and particle density, and porosity) of the chopped and hammer-milled wheat, barley, canola, and oat straw grinds measured were in the range of 0.98–4.22 mm, 36–80 kg m-3, 49–119 kg m-3, 600–1220 kg m-3, and 0.9–0.96, respectively. The average mean particle diameter was highest for the chopped wheat straw (4.22-mm) and lowest for the canola grind (0.98-mm). The canola grinds produced using the hammer mill (19.05-mm screen size) had the highest bulk and tapped density of about 80 and 119 kg m-3; whereas, the wheat and oat grinds had the lowest of about 58 and 88–90 kg m-3. The results indicate that the bulk and tapped densities are inversely proportional to the particle size of the grinds. The flow properties of the grinds calculated are better for chopped straws compared to hammer milled using smaller screen size (19.05 mm).

  8. Energy efficiency of cement finish grinding in a dry batch ball mill

    International Nuclear Information System (INIS)

    Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with torque measurement. The specific energy was found to be dependent on operating parameters and clinker environment. Additional compounds such as gypsum and pozzolanic tuff improve energy efficiency. The optimal parameters allowing maximising the energy efficiency factor were determined. Energy efficiency factors were obtained both on the crude material (size minus 2.8 mm) and on a sieved fraction (1-0.71 mm). They demonstrate that a low initial rate of breakage implies higher energy efficiency. On the contrary, conditions ensuring an initial maximal rate of breakage lead to an increase of the energy consumption

  9. Circuit high pressure grinding rolls (HPGR) in a cement grinding plant. Pt. 1. Evaluation of overall performance

    Energy Technology Data Exchange (ETDEWEB)

    Aydogan, Namik A.; Ergun, Levent [Hacettepe Univ., Ankara (Turkey). Mining Engineering Dept.

    2010-07-01

    In this paper, the performance of a closed circuit HPGR operation was evaluated by the data obtained from six measurements in a cement grinding circuit operating in Turkey. Flowrates of the streams and classifier performance were evaluated after mass balancing. The average specific energy consumption of the HPGR for six measurements was 9.62 kWh/t for grinding from 17.9 mm to 57 {mu}m (80 % passing size). Reduction ratio increased with the increase in specific energy consumption. Although cut point and the bypass of the classifier varied in a rather wide range, reduced efficiency curve and imperfection values indicated that the sharpness of separation remained the same. (orig.)

  10. 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.

  11. A study of energy-size relationship and wear rate in a lab-scale high pressure grinding rolls unit

    Science.gov (United States)

    Rashidi Dashtbayaz, Samira

    This study is focused on two independent topics of energy-size relationship and wear-rate measurements on a lab-scale high pressure grinding rolls (HPGR). The first part of this study has been aimed to investigate the influence of the operating parameters and the feed characteristics on the particle-bed breakage using four different ore samples in a 200 mm x 100 mm lab-scale HPGR. Additionally, multistage grinding, scale-up from a lab-scale HPGR, and prediction of the particle size distributions have been studied in detail. The results obtained from energy-size relationship studies help with better understanding of the factors contributing to more energy-efficient grinding. It will be shown that the energy efficiency of the two configurations of locked-cycle and open multipass is completely dependent on the ore properties. A test procedure to produce the scale-up data is presented. The comparison of the scale-up factors between the data obtained on the University of Utah lab-scale HPGR and the industrial machine at the Newmont Boddington plant confirmed the applicability of lab-scale machines for trade-off studies. The population balance model for the simulation of product size distributions has shown to work well with the breakage function estimated through tests performed on the HPGR at high rotational speed. Selection function has been estimated by back calculation of population balance model with the help of the experimental data. This is considered to be a major step towards advancing current research on the simulation of particle size distribution by using the HPGR machine for determining the breakage function. Developing a technique/setup to measure the wear rate of the HPGR rolls' surface is the objective of the second topic of this dissertation. A mockup was initially designed to assess the application of the linear displacement sensors for measuring the rolls' weight loss. Upon the analysis of that technique and considering the corresponding sources of errors, the application of the 2D distance measurement sensors was studied to directly determine the wear rate on the lab-sale HPGR roll. Results obtained from various grinding tests revealed that the operating variations were beyond the expected wear rate. Based on the valuable outcomes from the two mentioned experimental designs, a cup-disc arrangement similar to piston-die apparatus was developed to indirectly measure the wear rate on the HPGR roll. The preliminary outputs proved to be promising for further investigation into the development of this method in order to relate the measured data on the cup-disc apparatus to the actual wear rate on the HPGR rolls.

  12. Slip Line Field Solution for Second Pass in Lubricated 4-High Reversing Cold Rolling Sheet Mill

    OpenAIRE

    Oluleke O. Oluwole; Olayinka Olaogun

    2011-01-01

    The development of a possible slip line field (slf) for theoretical calculations of the deforming pressure (load) in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium sheet rolling mill was done in this work. This will be relevant in the manufacturing industries providing an easy method for determining necessary applied rolling load. Experimental rolling was carried out to observe the shear lines in the deformation field. Construction of possi...

  13. Influence of a matrix on properties of mottled cast iron applied for mill rolls

    OpenAIRE

    Krawczyk, J; J. Pacyna

    2010-01-01

    Mill rolls are ones of the most expensive tools applied in plastic working processes and have to satisfy several criteria, which allow them to be used. Cast iron mill rolls, due to their fracture toughness and tribological properties, are the most often applied at hot-rolling in the last rolling stands. This results from the smallest dynamic loads of such rolling stands and the decisive influence of the surface quality of these tools on the surface quality of the rolled product. An improper m...

  14. Bayesian model mixing for cold rolling mills: Test results.

    Czech Academy of Sciences Publication Activity Database

    Ettler, P.; Puchr, I.; Dedecius, Kamil

    Slovensko : Slovak University of Technology, 2013, s. 359-364. ISBN 978-1-4799-0926-1. [19th International Conference on Process Control. Štrbské Pleso (SK), 18.06.2013-21.06.2013] R&D Projects: GA MŠk(CZ) 7D09008; GA MŠk 7D12004 Keywords : Bayesian statistics * model mixing * process control Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2013/AS/dedecius-bayesian model mixing for cold rolling mills test results.pdf

  15. 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.

  16. Crush Grinding

    International Nuclear Information System (INIS)

    Crush Grinding is a special process used at the Kansas City Plant to finish stem sections of reservoir products. In this process, a precise profile of the desired product is formed on a tungsten carbide roll. This roll slowly transfers a mirror image of the profile onto the grinding surface of a wheel. The transfer rate of the profile is between 0.001 and 0.010 inches per minute. Crush grinding is desirable since it provides consistent surface finishes and thin walls at a high production rate. In addition, it generates very sharp fillet radii. However, crush grinding is a complex process since many variables affect the final product. Therefore, the process requires more attention and knowledge beyond basic metal removal practices. While the Kansas City Plant began using these machines in 1995, a formal study regarding crush grinding has not been conducted there. In addition, very little literature is available in the grinding industry regarding this process. As a result, new engineers at the Kansas City Plant must learn the process through trial and error. The purpose of this document is to address this literature deficit while specifically promoting a better understanding of the stem crush grinding process at the Kansas City Plant.

  17. Numerical And Experimental Study On Producing Aluminum Alloy 6061 Shafts By Cross Wedge Rolling Using A Universal Rolling Mill

    Directory of Open Access Journals (Sweden)

    Tofil A.

    2015-06-01

    Full Text Available The paper presents a selection of numerical and theoretical results of the cross wedge rolling process for producing stepped shafts made of aluminum alloy 6061. The numerical modeling was performed using the FEM-based Simufact Forming simulation software. In the simulations, we examined the kinematics of metal flow and determined the distribution patterns of effective strains, temperatures, axial stresses and the Cockroft-Latham damage criterion. Variations in the rolling forces were determined, too. The numerical results were verified experimentally using a universal rolling mill designed and constructed by the present authors. This machine can be used to perform such processes as cross wedge rolling, longitudinal rolling and round bar cropping. During the experiments, we examined process stability and finished product geometry and recorded the torques. The experimental results confirm that axisymmetric aluminum alloy shafts can be produced by cross wedge rolling with two rolls. Last but not least, the experiments served to evaluate the technological potential of the rolling mill used.

  18. IMPROVEMENT PROCESS FOR ROLLING MILL THROUGH THE DMAIC SIX SIGMA APPROACH

    Directory of Open Access Journals (Sweden)

    Kunal Ganguly

    2012-09-01

    Full Text Available This project aims to address the problems that are facing a large aluminum company in a Developing Hot Rolling Mill Capabilities for Wider Widths Hard Alloys Rolling and b Eliminate down time due to strip /coil slippage during hard alloys 5xxx rolling at Hot Mill. The challenge for the company was to cater the fast changing export demand for Flat Rolled products with its existing resources. By applying Six Sigma principles, the team identified the current situation that the rolling mills operations were in. Si x Sigma DMAIC methodologies were use d in the project to determine the project's CTQ characteristics, defining the possible causes, Identifying the variation sources, establishing variable relationships and Implementing Control Plans. The project can be useful for any company that needs to fi nd the most cost efficient way to improve and utilize its resources.

  19. A small economical rolling mill for producing foils used as nuclear targets

    Energy Technology Data Exchange (ETDEWEB)

    Greene, J.P.; Thomas, G.E.

    1996-11-01

    A small, economical rolling mill has found extensive use in the Physics Division Target Development Laboratory for producing foils used in atomic and nuclear physics experiments. This apparatus is quite versatile for its size and enables a large fraction of our target foil requirements to be realized in-house. A description of the rolling mill and some examples of targets produced will be given.

  20. INVESTIGATION OF THE MAINTENANCE ORGANISATION FOR HOT ROLLING MILLS

    Directory of Open Access Journals (Sweden)

    P.K. Pretorius

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Production systems have undergone dramatic changes in recent years. Many companies have implemented new technologies such as flexible manufacturing systems. There is therefore a shift in focus to maintenance and the effective management thereof. Maintenance is a dynamic activity and is comprised of a large number of interacting variables. An effective maintenance organisation is required to control these variables .
    This paper discusses the building of a maintenance organisation and the aspects that should be considered during the design. The way in which five companies that operate hot rolling mills apptoached the problem of building an effective maintenance organisation was investigated.

    AFRIKAANSE OPSOMMING: y eryaardigingstelsels het drastiese veranderinge ondergaan die afgelope aantal jaar. Verskeie Il1~atskappyemaak nou gebruik van nuwe tegnologiee, soas byvoorbeeld aanpasbare vervaardigingstelsels. Daar is gevolglik 'n verskuiwing in fokus na instandhouding en die effektiewe bestuur daarvan. lnstandhouding is 'n dinamiese aktiwiteit en behels 'n groot aantal ' gekoppelde veranderlikes. 'n Effektiewe instandhoudingsorganisasie word benodig om hierdie v'eranderlikes te beheer.
    Hierdie artikel bespreek die daarstelling van die instandhoudingsorganisasie en die parameters V~toorweeg moet word tydens die ontwerp. Die wyse waarop vyf maatskappye wat }V~rIl1walse bedryf die ontwikkeling van 'neffektiewe organisasie vir instandhouding benader hc(is ondersoek .

  1. Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills

    International Nuclear Information System (INIS)

    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 deg. C for 60 minutes and given stepped austempering treatment at 280 deg. C for 30 minutes and 60 minutes followed by 380 deg. 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.

  2. Premature failure analysis of forged cold back-up roll in a continuous tandem mill

    International Nuclear Information System (INIS)

    Highlights: ? Metal wrapping and strip welding in work/back-up rolls contact zone caused spalling. ? MnS inclusion and pore initiated crack which propagated in milling led to spalling. ? Retained austenite conversion to ?'-martensite accelerated spalling failure. ? Needle shaped carbide (Fe,Mo,Cr)7C3, may cause poor service life of back-up roll. -- Abstract: In this paper, premature failure of a forged back-up roll from a continuous tandem mill was investigated. Microstructural evolutions of the spalled specimen and surface of the roll were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and ferritscopy, while hardness value of the specimen was measured by Vickers hardness testing. The results revealed that the presence of pore and MnS inclusion with spherical and oval morphologies were the main contributing factors responsible for the poor life of the back-up roll. In addition, metal pick up and subsequently strip welding on the surface of the work roll were found as the major causes of failure in work roll which led to spalling occurrence in the back-up roll. Furthermore, relatively high percentage of retained austenite, say 9%, in outer surface of the back-up roll contributed spalling due to conversion of this meta-stable phase to martensite and creation of volume expansion on the outer surface through work hardening during mill campaign.

  3. Motion of grinding media in axial direction and its effect on comminution in an agitation beads mill; Baitai kakuhangata model funsaiki ni okeru baitai no jikuhoko undo to funsai koka

    Energy Technology Data Exchange (ETDEWEB)

    Hashi, Y. [Ashizawa Ltd., Chiba (Japan); Senna, M. [Keio University, Tokyo (Japan). Faculty of Science and Technology

    1995-05-10

    Grinding tests were carried out using a model agitation beads mill with a single disc. Four different discs were used to examine the effect of the motion of the grinding media in the axial direction. The median diameter of the ground products decreased with increasing movement of the grinding media in the axial direction under the same degree of filling of the grinding media and speed of rotation. Contamination in the product from the agitating element and grinding vessel increased with increasing energy input, irrespective of the shape of the agitating disc. Contamination from the grinding media increased with increase in the movement of grinding media in axial direction. The motion of grinding media in the axial direction is concluded to cause mutual collision and hence to increase abrasion of the grinding media. 8 refs., 10 figs.

  4. A model-based predictive control scheme for steal rolling mills using neural networks

    Scientific Electronic Library Online (English)

    J. M., Gálvez; Luis E., Zárate; H., Helman.

    2003-03-01

    Full Text Available A capital issue in roll-gap control for rolling mill plants is the difficulty to measure the output thickness without including time delays in the control loop. Time delays are a consequence of the possible locations for the output thickness sensor, which usually is located some distance away from t [...] he roll gap. In this work, a new model-based predictive control law is proposed. The new scheme is a neural network based predictive control structure which is applied to roll-gap control with outstanding results. It is shown that the neural network based predictive control permits to overcome the existing time delays in the system dynamics. The proposed scheme implements a virtual thickness sensor, which releases an accurate estimate of the actual output thickness. It is shown that the dynamic response of the rolling mill system can be substantially improved by using the proposed controller. Simulation results are presented to illustrate the controller performance.

  5. The new PFEIFFER roller mill MVR. Reliable grinding technology for high throughput rates; Die neue PFEIFFER-MVR-Walzenschuesselmuehle. Sichere Mahltechnik fuer grosse Durchsaetze

    Energy Technology Data Exchange (ETDEWEB)

    Reichardt, York [Gebr. Pfeiffer AG, Kaiserslautern (Germany). Process Engineering Dept.

    2010-07-01

    In the cement industry, the trend is towards ever increasing grinding capacities of individual grinding plants. As a result, plant availability and optimized maintenance concepts are becoming more and more important. The newly developed MVR roller mill from Gebr. Pfeiffer AG for grinding cement raw material, cement clinker, and additives with an installed power of up to 12 000 kW does in fact fulfill these customer requirements perfectly. The modular design of the MVR mill comprising 4 to 6 grinding rollers allows the continuation of mill operation even if one roller module is not available. The same applies to the new MultiDrive {sup registered} design of the mill drive consisting of up to 6 identical drive units in the range of 2000 kW each. So mill operation may continue while maintenance work is being performed on a drive unit. Hence any unplanned downtimes are considerably reduced even in the case of an outage of the main components. (orig.)

  6. The effect of ZrO{sub 2} grinding media on the attrition milling of FeAl with Y{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Gedevanishvili, S.; Deevi, S.C

    2004-03-25

    Attrition milling of water and gas atomized FeAl was carried out with Y{sub 2}O{sub 3}, where ZrO{sub 2} was used as a grinding media in place of stainless steel balls to avoid contamination with Cr and C. Consolidation of the milled powders produced complex FeAl phases containing Zr which doubled the hardness and significantly improved the creep resistance as compared to that of unmilled and consolidated FeAl.

  7. Fluid mechanics of slurry flow through the grinding media in ball mills

    Energy Technology Data Exchange (ETDEWEB)

    Songfack, P.K.; Rajamani, R.K. [Univ. of Utah, Salt Lake City, UT (United States). Comminution Center

    1995-12-31

    The slurry transport within the ball mill greatly influences the mill holdup, residence time, breakage rate, and hence the power draw and the particle size distribution of the mill product. However, residence-time distribution and holdup in industrial mills could not be predicted a priori. Indeed, it is impossible to determine the slurry loading in continuously operating mills by direct measurement, especially in industrial mills. In this paper, the slurry transport problem is solved using the principles of fluid mechanics. First, the motion of the ball charge and its expansion are predicted by a technique called discrete element method. Then the slurry flow through the porous ball charge is tackled with a fluid-flow technique called the marker and cell method. This may be the only numerical technique capable of tracking the slurry free surface as it fluctuates with the motion of the ball charge. The result is a prediction of the slurry profile in both the radial and axial directions. Hence, it leads to the detailed description of slurry mass and ball charge within the mill. The model predictions are verified with pilot-scale experimental work. This novel approach based on the physics of fluid flow is devoid of any empiricism. It is shown that the holdup of industrial mills at a given feed percent solids can be predicted successfully.

  8. Wireless Remote Monitoring System for the Agc Svibration Fault of Rolling Mill

    OpenAIRE

    Yan Gao; Baoquan Jin; Hongjuan Zhang

    2013-01-01

    The rolling mill screw down AGC system sets several subsystems of machinery, electronics, hydraulics, controls in one. Under the action of responding extreme frequency or external disturbances, the non design objective coupling between the subsystems may be excited, and causing the most serious vibration, seriously impact product quality or even cause great destruction. Aiming at the defects in fault diagnosis and control system of the traditional rolling m...

  9. Advanced Soft Sensor Technology to be Used for Cold Rolling Mills.

    Czech Academy of Sciences Publication Activity Database

    Ettler, P.; Dedecius, Kamil; Juri?i?, D.; Preglej, A.

    Toulouse : IEEE, 2011, s. 1-4. ISBN 978-1-4577-0016-3. [16th IEEE International Conference on Emerging Technologies and Factory Automation ETFA'2011. Toulouse (FR), 05.09.2011-09.09.2011] R&D Projects: GA MŠk(CZ) 7D09008 Institutional research plan: CEZ:AV0Z10750506 Keywords : soft sensor * rolling mill Subject RIV: IN - Informatics, Computer Science http://library.utia.cas.cz/separaty/2011/AS/dedecius-advanced soft sensor technology to be used for cold rolling mills.pdf

  10. Extended Kalman Filter Based Neural Networks Controller For Hot Strip Rolling mill

    International Nuclear Information System (INIS)

    The present paper deals with the application of an Extended Kalman filter based adaptive Neural-Network control scheme to improve the performance of a hot strip rolling mill. The suggested Neural Network model was implemented using Bayesian Evidence based training algorithm. The control input was estimated iteratively by an on-line extended Kalman filter updating scheme basing on the inversion of the learned neural networks model. The performance of the controller is evaluated using an accurate model estimated from real rolling mill input/output data, and the usefulness of the suggested method is proved

  11. Force prediction in cold rolling mills by polynomial methods

    Directory of Open Access Journals (Sweden)

    Nicu ROMAN

    2007-12-01

    Full Text Available A method for steel and aluminium strip thickness control is provided including a new technique for predictive rolling force estimation method by statistic model based on polynomial techniques.

  12. FEM SIMULATION OF THE TUBE ROLLING PROCESS IN DIESCHER’S MILL

    Directory of Open Access Journals (Sweden)

    Zbigniew Pater

    2014-06-01

    Full Text Available This paper deals with the issue of numerical modelling of the piercing process of a thick–walled bush in a two-rolled skew rolling mill, equipped with guiding devices of Diescher’s type. After a short characteristic of the subject matter, the developed geometric model of the process was discussed, with taking kinematics of tools movement and thermal phenomena present in metal during forming into consideration. Next, the results of calculations were presented in a form of fields of strain, damage criterion and temperature. Distributions of force parameters acting on particular tools during the process of bush rolling were also given.

  13. Fuzzy-Neural Control of Hot-Rolling Mill

    Directory of Open Access Journals (Sweden)

    Khearia Mohamad

    2010-12-01

    Full Text Available This paper deals with the application of Fuzzy-Neural Networks (FNNs in multi-machine system control applied on hot steel rolling. The electrical drives that used in rolling system are a set of three-phase induction motors (IM controlled by indirect field-oriented control (IFO. The fundamental goal of this type of control is to eliminate the coupling influence though the coordinate transformation in order to make the AC motor behaves like a separately excited DC motor. Then use Fuzzy-Neural Network in control the IM speed and the rolling plant. In this work MATLAB/SIMULINK models are proposed and implemented for the entire structures. Simulation results are presented to verify the effectiveness of the proposed control schemes. It is found that the proposed system is robust in that it eliminates the disturbances considerably.

  14. Evaluation of the fatigue damage of rolls for strip mills below the surface by x-ray diffraction method

    International Nuclear Information System (INIS)

    Technique of the X-ray diffraction line profile analysis has been applied to the study of fatigue damage below the surface of the work and the backup rolls of cold strip mill and the backup rolls of hot strip mill. Half value breadth has been taken as a measure of fatiguing. Fatigued zone below the surface of rolls is well correlated with the half contact length of roll, L; 0.03 L in the work roll of cold strip mill and 0.1 L in the other rolls. Changes in the half value breadth with increase in cycles of roll contact differ in accordance with the surface hardness of the rolls: continued cycling results in decrease of the half value breadth at surface in hard rolls (H sub(s) >= 60) and increase in soft rolls (H sub(s) <= 50). The technique of X-ray study of fatigue can be extended to prediction and prevention of accidental failure of rolls due to fatigue fracture such as spalling. Furthermore the amount of surface dressing at regular maintenance of rolls can be saved significantly on the basis of accurate evaluation of the depth of fatigue damaged zone. (author)

  15. Lubricant for clean rolling: Escapee oil particles keep cold rolling steel mills lubricated:

    OpenAIRE

    Graaf, A., van de

    2002-01-01

    One of the unique selling points of the Corus steel mills at IJmuiden is the quality of the steel they produce. The lubrication used during the last production stage is one of the factors that determine how clean and smooth the steel will emerge from the mill. The usual lubricant consists of an emulsion of oil in water. Until recently, little was known about the physical principles underlying the action of lubricant emulsions in steel mills. The only way to test new lubricants was by...

  16. Influence of a matrix on properties of mottled cast iron applied for mill rolls

    Directory of Open Access Journals (Sweden)

    J. Krawczyk

    2010-07-01

    Full Text Available Mill rolls are ones of the most expensive tools applied in plastic working processes and have to satisfy several criteria, which allow them to be used. Cast iron mill rolls, due to their fracture toughness and tribological properties, are the most often applied at hot-rolling in the last rolling stands. This results from the smallest dynamic loads of such rolling stands and the decisive influence of the surface quality of these tools on the surface quality of the rolled product. An improper microstructure of rolls can lead to their premature wearing, e.g. broken flanges, pivots twisting off etc. By means of the heat treatment the matrix microstructure and morphology of carbide precipitationscan be modified and this in-turn can influence cast iron properties.Determination of the influence of microstructure changes, caused by the heat treatment, on the properties of EN-GJN-HV300 low-alloycast iron, after its modification and spheroidization – is the aim of the present paper. Those changes are based on the formation pearlitic or bainitic matrices at the similar morphology of graphite and ledeburitic cementite precipitations. The performed investigations should enable designing the heat treatment of cast iron metallurgical rolls in such a way as to obtain the optimal microstructures for functional parameters of these type of tools. The influence of changing the pearlitic matrix into the bainitic one on such properties as: hardness, impact strength, tensile strength, creep limit, bending strength and a stress intensity factor KIc was investigated in this study. Samples for testing, the listed above mechanical properties, were taken from an industrial casting with care to have pieces of very similar crystallization conditions.

  17. Optimized simulation of vortex jet mill in waste rubber grinding technology by LNG

    Science.gov (United States)

    Han, Yuemei

    2015-07-01

    Frozen rubber powder has excellent qualities and application value, and it can be achieved from waste rubber after being crushed at low temperature used liquefied natural gas (LNG) as cryogen. Vortex jet mill was the key equipment to further crush the rubber particles which the pressure-air was jet into in the basic LNG technological process. After confirming the structure and size of the jet nozzle, the Height (H) between the nozzle and the bottom of the mill, the incident angle ? and the initial size of the rubber particles were changed then the continuous phase and the track of single particle were optimized in order to gain more excellent crushing effect. The results showed: the jetting gas were spiral rising in the mill and the speed of it was reduced, so the particle was graded by the gas. The impact and collision could reduce the particle diameter and crush them but the result was influenced by the initial size of the particle. The size of the original rubber particles must not be more than 110?m. The simulation was helpful and leading for the experiment.

  18. Strip/Foil Rolling Mill Stochastic Excitation Model and Its Stability

    Directory of Open Access Journals (Sweden)

    Baoyu Xu

    2012-06-01

    Full Text Available Based on the stochastic rolling force data from aluminum hot strip tandem mill, the ARMA time series model and the stochastic excitation power spectral density (PSD model are established, and the stochastic rolling forces excitation model is established by utilizing Levenberg-Marquardt combined with generalized global planning algorithm. A two dimensional stochastic nonlinear dynamical model of rolls is presented considering the stochastic factor of the rolling force. The Hamilton function is also described as one dimension diffusion process by using stochastic average method, the singular boundary theory was taken for analyzing the global stochastic stability of the system, and the system’s stochastic stability was researched by solving the Fokker-Planck-Kolmogorov (FPK equation. The results show that the stochastic excitation model obtained has significance for analyzing and researching stochastic dynamics characteristics to the system, and also generalized energy H in the range of 0.02 to 0.4, the system’s response has the minimum transition probability density, and the system state is not easy to change, therefore the system generalized energy H should be to limit in this range in the design and operation of the rolling mill.

  19. Online Prediction under Model Uncertainty Via Dynamic Model Averaging: Application to a Cold Rolling Mill.

    Czech Academy of Sciences Publication Activity Database

    Raftery, A. E.; Kárný, Miroslav; Ettler, P.

    Volume 52, Number 1 (2010), s. 52-66. ISSN 0040-1706 R&D Projects: GA MŠk 1M0572; GA MŠk(CZ) 7D09008 Institutional research plan: CEZ:AV0Z10750506 Keywords : prediction * rolling mills * Bayesian Dynamic Averaging Subject RIV: BC - Control Systems Theory Impact factor: 1.560, year: 2010 http://library.utia.cas.cz/separaty/2010/AS/karny-0342595.pdf

  20. Wireless Remote Monitoring System for the Agc Svibration Fault of Rolling Mill

    Directory of Open Access Journals (Sweden)

    Yan Gao

    2013-01-01

    Full Text Available The rolling mill screw down AGC system sets several subsystems of machinery, electronics, hydraulics, controls in one. Under the action of responding extreme frequency or external disturbances, the non design objective coupling between the subsystems may be excited, and causing the most serious vibration, seriously impact product quality or even cause great destruction. Aiming at the defects in fault diagnosis and control system of the traditional rolling mill, the wireless remote monitoring system for the rolling mill AGC system vibration fault is designed in this paper. Using the advanced sensor technology, PLC and configuration software, GPRS network technology, the parallel distributed data acquisition and data processing for the key servo element and the hydraulic parameters which can characterize the fault characteristics of the system can be done. The monitoring software system platform on line of the hydraulic AGC system based on Kingview is set up for centralized real-time monitoring. According to the collected multidisciplinary parameter the fault identification and location is done by using the fault diagnosis expert system based on Web, thus to make the preliminary evaluation for the operation and fault of hydraulic AGC system and provide advanced prediction and exclude strategy.

  1. Effect of powder milling on mechanical properties of hot-pressed and hot-rolled Cu–Cr–Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, A.K.; Narayana Murty, S.V.S.; Suresh Kumar, R. [Materials and Metallurgy Group, Vikram Sarabhai Space Centre, Trivandrum 695 022 (India); Mondal, K., E-mail: kallol@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

    2013-12-15

    Highlights: •Milled powder enhances sintering and mechanical properties after hot pressing. •Hot-rolling of hot-pressed samples made from milled powder enhances ductility. •Pore size and number of pores decreases after hot-rolling. -- Abstract: The present study is on the effect of mechanical milling of gas-atomized powders on mechanical properties of the hot-pressed and subsequently hot-rolled Cu–8 at% Cr–4 at% Nb alloy with a microstructure consisting of pure copper matrix hardened by intermetallic Cr{sub 2}Nb precipitates. The mechanically milled powders result in lower sintering temperature during hot pressing compared to the atomized powders. The hot-pressed samples made from the milled powder exhibit significantly higher hardness and tensile strength, but lower ductility and electrical conductivity compared to that made from the un-milled gas-atomized powders. The hot rolling results in marginal increase in strength, but significant increase in ductility compared to the hot-pressed alloy for both the milled and atomized powders and it is attributed to the decrease in size of the pores and amount of porosities after hot rolling.

  2. Bearing restoration by grinding

    Science.gov (United States)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  3. Neural compensation and modelling of a hot strip rolling mill using radial basis function

    Scientific Electronic Library Online (English)

    F.G., Rossomando; J., Denti F; A., Vigliocco.

    2011-07-01

    Full Text Available In this paper a Neural Compensation Strategy for a hot rolling mill process is proposed. The target of this work is to built a RBF-NN compensation approximation for the classical force feed forward and speed controller. A strategy based on neural networks is proposed here, because they are capable o [...] f modelling many nonlinear systems and their neural control via RBF-NN approximation. Simulations demonstrate that the proposed solution deals with disturbances and modeling errors in a better way than classic solutions do. The analysis of the RBF-NN approximation error on the control errors is included, and control system performance is verified through simulations.

  4. A comparison of the results obtained from grinding in a stirred media mill lignite coal samples treated with microwave and untreated samples

    Energy Technology Data Exchange (ETDEWEB)

    S. Samanli [Zonguldak Karaelmas University, Zonguldak (Turkey). Mining Engineering Department

    2011-02-15

    Various studies have been carried out on the effect of microwave-treatment on grinding different types of coal. However, the effect of microwave treatment on grinding coal samples -3.35 mm in size which can be considered to be fine is still under investigation. The purpose of this paper is to make contributions to these studies conducted. In the study, lignite coal samples with pyritic sulphur and 25% structural moisture were crushed below -3.35 mm particle size using jaw and cone crushers and then classified into three different mono size groups by Russel sieve. For a complete removal of the structural moisture from the lignite coal, a microwave application with 600 W needs approximately 35% more energy consumption than that with 850 W. The untreated coal samples and the ones treated with microwave at 850 W were ground for 5, 15, 30, 60, 120 s in a stirred media mill. The breakage rates of microwave-treated coal increased and accordingly the ground products of microwave-treated coal yielded finer particles than -106 {mu}m as compared to untreated coals. The untreated and microwave-treated feed coals of -3350 {mu}m and -1180 {mu}m particle sizes were ground for 2 min in the stirred media mill. It was found that the increases in the rate of weight percentages for -106 {mu}m particle size fraction after 2 min of grinding of untreated and microwave-treated feed coals of -3350 {mu}m and -1180 {mu}m were found to be 15.81% and 2.69%, respectively. Moreover, Hardgrove Index (HGI) test results of lignite coal showed that the HGI index value increased by approximately 23% after microwave treatment with 850 W. 37 refs., 11 figs., 4 tabs.

  5. Effect of blade geometry on motion of media particle and grinding characteristics in horizontal type sand mill and development of a new type of blade; Yokogata sand mill ni okeru kakuhan`yoku no kika keijo ga media ryushi no kyodo to funsai tokusei ni oyobosu eikyo to shingatayoku o kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Teshiba, T.; Takao, M.; Komori, S.; Murakami, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Yoshida, H. [Mitsubishi Heavy Indutries, Ltd., Tokyo (Japan)

    1996-07-10

    The motion of grinding media was visualized on three types of blade (normal disk type, hole disk type and cross type) for a horizontal type sand mill of which internal blade and external cylinder rotate inversely and independently. As a result, the effect of blade geometry on velocity distribution, the intensity of velocity fluctuations and appearance frequency of grinding media was made clear. The relationship between these flow characteristics and grinding rate was discussed by carrying out grinding tests of calcium carbonate. As a result, it is found that the grinding characteristics obtained for each blade in both rotation methods can be well correlated with the intensity of velocity fluctuations weighted by appearance frequency. A new type of blade (cross turbine type) was produced based on the above information, and its grinding rate was investigated in connection with the motion of the grinding media. The results showed that it has a higher rate of grinding than the three tides of blades previously used. 9 refs., 11 figs.

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

    OpenAIRE

    S K Garg; U.C. LOHANI; PANDEY, J.P.

    2010-01-01

    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 cons...

  7. Simulation of two Stands Cold Rolling Mill Process Using a Combination of Neural Networks and Genetic Algorithms to Avoid the Chatter Phenomenon

    Directory of Open Access Journals (Sweden)

    Behzad BahramiNejad

    2015-03-01

    Full Text Available Rolling mill Industry is one of the most profitable industries in the world. Chatter phenomenon is one of the key issues in this industry. Chatter or rolling unwanted vibrations not only has an adverse effect on product quality, but also reduces considerably the efficiency with reduced rolling velocities of rolling lines. This paper is an attempt to simulate the phenomenon of Chatter more accurate than the previous performed simulations. In order to increase the production speed, it needs to avoid parameters which effect on the Chatter and varieties with the rolling lines condition. Actual values of these parameters were determined in the archives of the Mobarakeh two stand cold rolling mills and collected on the 210 case study of real chattering. To simulate the experiment, a neural network is trained and weights and bias values of the neural network with genetic optimization algorithm were used to get an optimal neural network which reduces bugs on the test data. So this model is capable to predict speed of Chatter threshold on rolling process of two stand cold rolling mill with the accuracy less than one percent. So it can be used in rolling process with the building intelligent recognition systems to prevent the creator conditions of the chatter frequency range.

  8. MOLIENDA DE CLINKER DE CEMENTO: EVALUACIÓN DE LA INFLUENCIA DE LA VELOCIDAD DE GIRO DEL MOLINO, EL TIEMPO DE RESIDENCIA Y LA CARGA DE LOS MEDIOS DE MOLIENDA / CEMENT CLINKER GRINDING: EVALUATION OF MILL SPIN SPEED, RESIDENCE TIME AND GRINDING MEDIA LOAD

    Scientific Electronic Library Online (English)

    ADRIANA, OSORIO; GLORIA, RESTREPO; JUAN, MARÍN.

    2009-06-01

    Full Text Available se evaluó la molienda de clinker en molino de bolas, variando: velocidad del molino (24 y 72 RPM), tiempo de residencia (3 y 5 horas) y carga de cuerpos moledores (30 y 40 %), mediante un modelo factorial, el objetivo fue evaluar la incidencia de estos sobre el porcentaje másico pasante 45 micras y [...] el área superficial, factores determinantes en la calidad del cemento comercial. Se determinaron propiedades fisicoquímicas, de composición, naturaleza mineralógica y distribución granulométrica del material empleando Fluorescencia de Rayos X, Análisis de Área Superficial y Análisis Granulométrico por Tamizado. Se encontró que la cantidad de masa pasante de 45 micras crece al aumentar la velocidad del molino y en menor proporción al incrementar el tiempo, y que el cambio de carga de cuerpos moledores resulta insignificante. El área superficial aumenta al incrementarse velocidad, tiempo y carga; no obstante estos últimos en proporción menor que con la velocidad. Abstract in english In this study, the milling of clinker was evaluated by varying the mill speed (24 and 72 RPM), residence time (3 and 5 hours) and grinding media load (30 and 40 %) in a ball mill. The experiment was designed as a three level factorial statistical model. The main objective was to assess the effect of [...] these parameters on cumulative passing percentage (CPP) and surface area, both of which affect the quality of commercial cement. Physico-chemical properties, composition, mineralogy and granulometric distribution were determined using X Ray Fluorescence, Surface Area Analysis and Sieving Granulometric Analysis. Results showed that that CPP through a 325 mesh increases considerably with mill spin speed, that the rate of CPP increase decreases with residence time and that grinding media load changes were not significant. The surface area increased mainly as a function of increases in mill spin speed, while residence time and grinding media load had lesser impacts.

  9. Fabrication of cold-rolled sheet using 1700 mill in Karaganda metallurgical works

    International Nuclear Information System (INIS)

    Technical specifications are presented and the operation experience is summarized of the continuous five-cage cold rolling stand 1700 KarMK put into operation in 1973. The peculiarities of the technology of fabrication of cold-rolled strips of 0.5-2.0 mm thickness are considered. The factors of rolling various thickness and manufactured strips are analyzed, the optimum cogging conditions are recommended. Data on wearing and on changing of microrelief of shaft surface are given. The equipment available and the technology adopted ensure the fabrication of cold-rolled sheet in conformity with the state standard (GOST) requirements

  10. Catalytic surface modification of roll-milled poly({epsilon}-caprolactone) biaxially stretched to ultra-thin dimension

    Energy Technology Data Exchange (ETDEWEB)

    Foo, H.L. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Taniguchi, A. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Yu, H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Department of Physiology, National University of Singapore (Singapore); Okano, T. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Institute of Biomedical Engineering, Tokyo Women' s Medical University (Japan); Teoh, S.H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore) and Department of Mechanical Engineering, National University of Singapore (Singapore)]. E-mail: mpetsh@nus.edu.sg

    2007-03-15

    A novel roll-milling polymer processing technique along with biaxial stretching was used to fabricate 10 {mu}m thick poly({epsilon}-caprolactone) films. A less invasive collagen surface modification was used, involving a reaction between corona-preactivated membranes and ferrous-containing acrylic acid solution at the low temperature of 42 {sup o}C. Successful modified films were characterized by Toluidine Blue O assay and X-ray photoelectron spectroscopy. Human umbilical vein endothelial cells also showed both higher proliferation rate and differentiated cobblestone morphology on these collagen-immobilized substrates.

  11. The ways of increasing the socket accuracy in the course of broaching on a three-roll mill

    International Nuclear Information System (INIS)

    The results are presented of experimental investigations on the wall thickness variation of sleeves broached on a three-high mill with barrel-shaped rolls. To obtain sleeves with relatively accurate geometrical dimensions it is necessary to ensure a high rigidity of alignment of the sleeve-mandrel-rod system with a 3- to 4-fold safety margin for rod resistance to longitudinal bending with a length equal to that of the sleeve. Broaching is better to accomplish at increased feed angles (14-16 deg.) with partial cooling of the billets

  12. Catalytic surface modification of roll-milled poly(?-caprolactone) biaxially stretched to ultra-thin dimension

    International Nuclear Information System (INIS)

    A novel roll-milling polymer processing technique along with biaxial stretching was used to fabricate 10 ?m thick poly(?-caprolactone) films. A less invasive collagen surface modification was used, involving a reaction between corona-preactivated membranes and ferrous-containing acrylic acid solution at the low temperature of 42 oC. Successful modified films were characterized by Toluidine Blue O assay and X-ray photoelectron spectroscopy. Human umbilical vein endothelial cells also showed both higher proliferation rate and differentiated cobblestone morphology on these collagen-immobilized substrates

  13. Effect of rotation method of internal blade and external cylinder on media particles and grinding characteristics in horizontal type sand mill; Yokogata sand mill ni okeru uchihane to sotozutsu no kaiten hoshiki ga media ryushi nokyodo to funsai tokusei ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Teshiba, T.; Takao, M.; Komori, S.; Murakami, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Yoshida, H. [Mitsubishi Heavy Indutries, Ltd., Tokyo (Japan)

    1996-05-10

    A measuring technique to visualize the motion of media particles has been developed for a horizontal type sand mill, in which internal blade and external cylinder rotate inversely and independently. Using this experimental techniques velocity distribution, intensity of velocity fluctuations and appearance frequency of grinding media in the mill chart be measured. Relating to these flow characteristics of media particles for both rotation methods, the grinding performance of calcium carbonate with alumina beads is discussed. As a result, it is found that the median diameter of ground products obtained in both rotation methods can not be correlated only with the intensity of velocity fluctuations having been used to date, but can be correlated well with the intensity of velocity fluctuations weighted by appearance frequency. 7 refs., 11 figs.

  14. Maintenance strategy for tilting table of rolling mill based on reliability considerations

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, V.S.; Modak, J.P

    2003-04-01

    Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine. The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices.

  15. Maintenance strategy for tilting table of rolling mill based on reliability considerations

    International Nuclear Information System (INIS)

    Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine. The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices

  16. Preparation of super-clean coal. Effect of media size in stirred ball mill grinding. Technical progress report for the ninth and tenth quarters, September 15, 1985-March 14, 1986

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, R.H.; Adel, G.T.; Mankosa, M.J.

    1986-05-01

    As a prerequisite to producing super-clean coal with any physical coal cleaning process, such as microbubble flotation, the feed coal must be micronized to liberate finely disseminated mineral matter. The stirred ball mill is regarded as one of the most efficient devices for micronizing coal. Using a five-inch batch mill, the optimum operating conditions have been determined in terms of media size, the optimum operating conditions have been determined in terms of media size and media type. The rates of breakage determined with monosized feeds are compared on the basis of specific energy consumption. It has been found that a 20:1 ball size/particle size ratio gives optimum grinding conditions. 10 refs., 10 figs.

  17. Expert system for flatness control in aluminum foil rolling. Alumi haku mill keijo seigyo expert system

    Energy Technology Data Exchange (ETDEWEB)

    Konishi, M.; Nose, K.; Narazaki, H.; Iwatani, T.; Oshima, H.; Kitagawa, S. (Kobe Steel, Ltd., Kobe (Japan))

    1990-07-01

    This paper reports the application of an expert system for Automatic Flatness Control (AFC) in aluminum foil rolling. The expert system is connected with AFC, and adjusts the target shape pattern according to the material characteristics and the operating conditions. This system is developed on the UNIX work station, and consists of six units, three knowledge bases, and a working memory. It has shown the ability to improve all kinds of aluminum foil throughout an one year adaptation in the operational rolling process. By using this system, the speed of rolling was improved above 10 percent. The algorithm which maintains consistency among multiple control purposes and the adaptive inference method realized in this system proved to be useful as a paradigm of the knowledge base system for the control process. 1 ref., 6 figs.

  18. Strip thickness estimation in rolling mills from electrical variables in AC drives

    Scientific Electronic Library Online (English)

    N.S., Marcellos; J.F., Denti; G.C.D., Sousa.

    2009-12-01

    Full Text Available The large-scale utilization of steel in the modern society highlights the importance of the lamination process, and poses new demands for advanced technologies in the electromechanical equipments as well as for the control systems. Several process parameters, such as strip thickness, friction, tensi [...] on, temperature, and rolling speed have a strong influence in the quality of the final product, and strategic importance in the control system. This paper introduces a method to obtain the torque and rolling mechanical power estimates in real time, without utilization of lamination process models. In contrast to existing techniques, in this work these estimates are derived from stator electrical variables, readily available in AC drives. This work also discusses the utilization of the torque and rolling mechanical power estimates to determine input and output strip thickness, by means of a neural network. Simulation results are presented and compared to real industrial data to demonstrate the validity of the proposed technique.

  19. Grain refinement of magnesium alloy sheets by ARB using high-speed rolling mill

    International Nuclear Information System (INIS)

    Applications of ARB to magnesium alloys were limited due to low deformability. The authors recently found that the rollability of the alloys is significantly improved in highspeed rolling. It is supposed that the severe plastic deformation of magnesium alloy sheets is feasible if rolling in ARB processes is conducted at high speed. In this study, AZ31B and ZK60A sheets are processed by ARB up to five cycles at 423K with a speed of 1000m/min. Vickers hardness increases with increasing number of ARB cycles, while the tensile strength shows the maximum after the second cycle. The grain size is reduced significantly at the first cycle and decreases gradually from the second cycle. The mean grain sizes after five cycles are 1.6?m for AZ31B and 1.8?m for ZK60A. It is concluded that ARB using high-speed rolling is effective for grain refinement of magnesium alloys.

  20. Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling

    Scientific Electronic Library Online (English)

    Ricardo, Floriano; Daniel Rodrigo, Leiva; Stefano, Deledda; Bjørn Christian, Hauback; Walter José, Botta.

    2013-02-01

    Full Text Available MgH2 was processed by short time high-energy ball milling (BM) and cold rolling (CR). A new alternative processing route (CR + BM) using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were ev [...] aluated. The CR + BM processing (compared to BM and CR process) resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

  1. Finite element analysis of edge fracture of electrical steel strip in reversible cold rolling mill

    International Nuclear Information System (INIS)

    An electrical steel strip is commonly used as a core material in all types of electric transformers and motors. It is produced by a cold rolling process. In this paper, a damage mechanics based approach that predicts the edge fracture of an electrical steel strip during cold rolling is presented. We adopted the normal tensile stress criterion and the fracture energy method as a damage initiation criterion and a damage evolution scheme, respectively. We employed finite element analysis (FEA) to simulate crack initiation and propagation at the initial notch located at the edges of the strip. The material constants required in FEA were experimentally obtained by tensile tests using a standard and a notched sheet type specimen. The results reveal that the edge crack was initiated at the entrance of the roll bite and that it rapidly evolved at the exit. The evolution length of the edge crack increased as the length of the initial notch as well as front tension reel force of the strip increased

  2. Longitudinal Grinding of Aspen

    OpenAIRE

    Thapa, Rinez

    2011-01-01

    The aim of this thesis work was to find out the paper properties obtained from longitudinal grinding of aspen. Mechanical Pulping, longitudinal grinding and short description of studied paper properties were introduced in the theoretical part. The entire process included longitudinal grinding of aspen. There were five different points at which aspen were cut for longitudinal grinding. The points were at an angle of 00, 150,300,450 and 00 with reference of traditional grinding. For each p...

  3. Increasing energy efficiency of grinding media through microscale comminution studies

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Y.C.; Goller, G.A. [GS Technologies/Control International Inc., Salt Lake City, UT (United States)

    1995-12-31

    Microscale studies involving an ultrafast load cell have been shown to provide direct and accurate measurements of particle strength, particle fracture energy and particle breakage functions under different loading geometry conditions. The effect of grinding media size, shape, density and surface properties on the energy efficiency can be quantitatively determined for different materials to be ground. The applications of microscale comminution studies have been demonstrated to provide good predictions of grinding mill performance with different grinding media.

  4. Design of two bearings with sealing system for the top roll shaft of sugar cane mill

    Scientific Electronic Library Online (English)

    Walter, Mora Perdomo; John Sandro, Rivas Murillo; John Jairo, Coronado Marín.

    2005-12-01

    Full Text Available Las chumaceras de bronce utilizadas actualmente en los molinos de caña de azúcar presentan elevado desgaste debido, entre otros factores, a la materia extraña que ingresa en ella cuando el eje superior se eleva (flota) por efecto del colchón de caña que pasa entre las mazas y al sobrecalentamiento c [...] ausado por fallas en los sistemas de lubricación y refrigeración. Con el objetivo de solucionar estos problemas dos diseños de chumaceras fueron realizados: uno con refrigeración en la caja y otro con refrigeración en la teja, ambos usando un sistema de sellado. Análisis por Elementos Finitos del comportamiento mecánico y térmico de los diseños garantiza un buen desempeño en operación. Abstract in english The bronze bearings currently used in sugar cane mills undergo an excessive wear due to both, the extraneous matter entering in the bearing gap when the shaft lift by effect of cane passing through the mill and heating caused by failures in both the lubrication and the refrigeration systems. In orde [...] r to solve this problems two bearing were designed: one cooled in the box and other cooled in the roofing tile, both using a sealing system. Finite Elements Analysis of the designs showed that they will have a good mechanical and thermal performance.

  5. Possibilities of enhancing the rolling quality in the course of deformation of high-alloy steel ingots on the roughing mill

    International Nuclear Information System (INIS)

    At the Dneprospetsstal' plant the variation in power parameters of rolling, the temperature and plasticity of the metal on deformation of ingots of stainless steels 10Kh23N18, 10Kh17N13M2T, and 12Kh18N10T have been investigated on a 950 mill. Upon combined analysis of the variations in the deformation conditions and the properties of the metal in the course of rolling, one can recommend the ways for improving the quality of the rolled stock and the mill efficiency. In the rolling of 2.8-ton (metric), 540x540 mm ingots, the lowest plasticity , nsub(k) is observed before the pass 15-16 because of the presence of a cast structure in the initial passes and the temperature drop in the subsequent ones. One must reduce compressions in these passes, and increase them in the others. It is also expedient to allow a short overheating (for 15-20 min) of the ingot surface up to 1300 deg C (30-50 deg. above the optimum)

  6. Improving Thermal Efficiency Of Push Type Furnace In A Hot Re-Rolling Steel Mill By Direct Method : Case Study

    Directory of Open Access Journals (Sweden)

    Jeetendra Mohan Khare

    2013-04-01

    Full Text Available Rolling is the process of reducing the thickness or changing the cross-section of a long work-piece by compressive forces applied through a set of rolls. Rolling accounts for about 90% of all metals produced by metalworking processes. The purpose of Rolling is to convert larger sections into smaller sections, which can be used directly in as rolled state or as stock for working through other processes. As a result of rolling, the coarse structure of cast ingot is converted into a fine grained structure

  7. Improving Thermal Efficiency Of Push Type Furnace In A Hot Re-Rolling Steel Mill By Direct Method : Case Study

    OpenAIRE

    Jeetendra Mohan Khare; Sandip Kumar Mishra; Shashank Shrivastava

    2013-01-01

    Rolling is the process of reducing the thickness or changing the cross-section of a long work-piece by compressive forces applied through a set of rolls. Rolling accounts for about 90% of all metals produced by metalworking processes. The purpose of Rolling is to convert larger sections into smaller sections, which can be used directly in as rolled state or as stock for working through other processes. As a result of rolling, the coarse structure of cast ingot is converted into a fine grained...

  8. Using Variable Perturbation Method to Study the Stability of Torsional Self-Excited Vibration in Main Drive System of Rolling Mill

    Directory of Open Access Journals (Sweden)

    Fenglan Wang

    2013-06-01

    Full Text Available The self-excited vibration of blooming mill is a kind of torsional vibration, which occurs only when the rolling machine slips under appropriate conditions. Once in place, this may cause the larger peak pressure of each component in the main drive system; reduce the service life of the components, cause components? damage directly. A large number of studies have shown that, at present there are not effective methods for diagnosis, monitoring of slipping and take proper measures in time to stop slipping so as to avoid the occurrence of malignant accidents. In this paper, author set out from another angle, take the main drive system of rolling mill as an example, to study stability of self-excited vibration. The conditions of the stable vibration are gained. By combining with the actual working conditions of blooming mill, author has put forward some effective measures to meet the stable conditions in order to make the blooming mill work in the stable state. Practice research has proved that the effective measures can contribute to reduce structural damage directly caused by the torsional vibration when “slipping” phenomenon occurred and to extend the service life of the components.

  9. Ultra-fine grinding and mechanical activation of mine waste rock using a high-speed stirred mill for mineral carbonation

    Science.gov (United States)

    Li, Jia-jie; Hitch, Michael

    2015-10-01

    CO2 sequestration by mineral carbonation can permanently store CO2 and mitigate climate change. However, the cost and reaction rate of mineral carbonation must be balanced to be viable for industrial applications. In this study, it was attempted to reduce the carbonation costs by using mine waste rock as a feed stock and to enhance the reaction rate using wet mechanical activation as a pre-treatment method. Slurry rheological properties, particle size distribution, specific surface area, crystallinity, and CO2 sequestration reaction efficiency of the initial and mechanically activated mine waste rock and olivine were characterized. The results show that serpentine acts as a catalyst, increasing the slurry yield stress, assisting new surface formation, and hindering the size reduction and structure amorphization. Mechanically activated mine waste rock exhibits a higher carbonation conversion than olivine with equal specific milling energy input. The use of a high-speed stirred mill may render the mineral carbonation suitable for mining industrial practice.

  10. 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.

  11. AISI/DOE Advanced Process Control Program Vol. 3 of 6: MICROSTRUCTURAL ENGINEERING IN HOT-STRIP MILLS Part 2 of 2: Constitutive Behavior Modeling of Steels Under Hot-Rolling Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yi-Wen Cheng; Patrick Purtscher

    1999-07-30

    This report describes the development of models for predicting (1) constitutive behaviors and (2) mechanical properties of hot-rolled steels as functions of chemical composition, microstructural features, and processing variables. The study includes the following eight steels: A36, DQSK, HSLA-V, HSLA-Nb, HSLA-50/Ti-Nb, and two interstitial-free (IF) grades. These developed models have been integrated into the Hot-Strip Mill Model (HSMM), which simulates the hot strip rolling mills and predicts the mechanical properties of hot-rolled products. The HSMM model has been developed by the University of British Columbia-Canada as a part of project on the microstructural engineering in hot-strip mills.

  12. Estudo de variabilidade e otimização do circuito de moagem SAG da Usina do Sossego Optimization of the Sossego SAG mill grinding circuit

    Directory of Open Access Journals (Sweden)

    Maurício Bergerman

    2009-03-01

    Full Text Available A Mina do Sossego, localizada na região sudeste do Estado do Pará, foi a primeira usina da Vale a operar um moinho SAG para processar minério de cobre e ouro. Nos primeiros três anos de operação, foram estudadas alternativas para aumento de produção, principalmente focadas em aspectos operacionais da moagem SAG. Em seguida, foram realizados estudos visando a identificar o desempenho do circuito em função dos diferentes tipos de minérios alimentados. Uma caracterização completa do minério foi realizada em conjunto com a calibração de modelos matemáticos baseados em amostragens conduzidas no circuito industrial. O simulador foi então usado para prever níveis de produção associados a cada tipo de minério, assim como determinar configurações otimizadas para o circuito. Esse artigo descreve em detalhes os principais aspectos da otimização do circuito, assim como o método para prever a produção em função das características do minério e do circuito.Sossego was the first Vale SAG mill operation to process copper-gold ore. It is located in the State of Para, southeastern Amazon region of Brazil. In the first three years of continuous operation, Vale investigated different alternatives for improving the circuit’s performance by investigating operating conditions, mainly focusing on the SAG mill. It was decided to further assess the performance of the comminution circuit as a function of ore characteristics. A comprehensive ore characterization program was then conducted, together with the calibration of mathematical models on the basis of surveys carried out at the industrial circuit. The simulator was then used to predict the throughput associated to each ore type, as well as to establish the optimized circuit configuration and tailored operating conditions. This paper describes in detail the main aspects of optimizing the industrial circuit performance, as well as the successful method for predicting the production as a function of ore characteristics and circuit configuration.

  13. Estudo de variabilidade e otimização do circuito de moagem SAG da Usina do Sossego / Optimization of the Sossego SAG mill grinding circuit

    Scientific Electronic Library Online (English)

    Maurício, Bergerman; Homero, Delboni; Marco, Nankran.

    2009-03-01

    Full Text Available A Mina do Sossego, localizada na região sudeste do Estado do Pará, foi a primeira usina da Vale a operar um moinho SAG para processar minério de cobre e ouro. Nos primeiros três anos de operação, foram estudadas alternativas para aumento de produção, principalmente focadas em aspectos operacionais d [...] a moagem SAG. Em seguida, foram realizados estudos visando a identificar o desempenho do circuito em função dos diferentes tipos de minérios alimentados. Uma caracterização completa do minério foi realizada em conjunto com a calibração de modelos matemáticos baseados em amostragens conduzidas no circuito industrial. O simulador foi então usado para prever níveis de produção associados a cada tipo de minério, assim como determinar configurações otimizadas para o circuito. Esse artigo descreve em detalhes os principais aspectos da otimização do circuito, assim como o método para prever a produção em função das características do minério e do circuito. Abstract in english Sossego was the first Vale SAG mill operation to process copper-gold ore. It is located in the State of Para, southeastern Amazon region of Brazil. In the first three years of continuous operation, Vale investigated different alternatives for improving the circuit’s performance by investigating oper [...] ating conditions, mainly focusing on the SAG mill. It was decided to further assess the performance of the comminution circuit as a function of ore characteristics. A comprehensive ore characterization program was then conducted, together with the calibration of mathematical models on the basis of surveys carried out at the industrial circuit. The simulator was then used to predict the throughput associated to each ore type, as well as to establish the optimized circuit configuration and tailored operating conditions. This paper describes in detail the main aspects of optimizing the industrial circuit performance, as well as the successful method for predicting the production as a function of ore characteristics and circuit configuration.

  14. Effects of grinding on certain crystalline structures

    International Nuclear Information System (INIS)

    The effects of grinding on certain crystalline substances (ZnO, ZnS, Sb), have been studied using X-ray diffraction and electron microscopy. The treatments were carried out using a vibrating mill which involves a higher energy than more conventional equipment such as ball-mills. Various methods have been proposed for determining the width of the intrinsic profile (?). In the case of zinc oxide it has been shown possible to differentiate the respective contributions of the fragmentation effects and of lattice deformation effects to the overall effects of the grinding. For the two types of zinc sulfide (blend and Wurtzite) it has been shown that the blend-wurtzite) transition point is very much decreased, and that the rate of transformation of wurtzite into the stable form (blend) at room temperature is considerably increased by the grinding. In the case of antimony, the method of fragmentation shows the existence of an anisotropy which appears to be connected with easily cleavable planes. These observations show that in the case of grinding carried out with sufficient energy, the accumulation of this energy in the matter through the creation of lattice defects can accelerate the reaction rate or bring about physical transformations. (author)

  15. Influence of the charged amount of ball media on grinding speed in wet rotational ball milling; Sisshiki kaiten ball mill no funsai sokudo ni oyobosu ball jutenryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, K.; Watanabe, H.; Tomino, H.; Kondo, Y. [Kagawa Industrial Tech. Center, Kagawa (Japan)

    1998-07-01

    For preparation method of the ceramics raw materials, number of new methods called build-up method were researched and developed to make possible to prepare powders with high purity and sub-micron size. However, there are a lot of raw materials for ceramics prepared by crashing raw materials synthesized by using solid phase reaction and others even at present. In order to obtain fine powder, as wet type crashing method is adopted and some methods such as vibration ball-mill using balls for crashing media, and medium stirring mill are investigated, wet type rotary ball-mill method used long years ago is adopted as a dominant method. In this research, for crashing of alumina due to the wet type rotary ball-mill method using four kinds of small diameter ball, effect of ball filling and pot rotation number on crashing speed was investigated. As a result, it could be obtained some informations such as possibility of increasing the crashing speed by selecting the ball filling and rotation number, and so forth. 7 refs., 7 figs., 1 tab.

  16. 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.

  17. Effect of particle size on performance. 3. Grinding pelleting interactions.

    Science.gov (United States)

    Nir, I; Hillel, R; Ptichi, I; Shefet, G

    1995-05-01

    Three experiments were conducted to study the effect of particle size obtained by grinding wheat and sorghum in a hammer mill (HM) or roller mill (RM) on broiler performance. Broilers were fed a mash diet or crumbles to 4 wk of age, then pellets to 7 wk of age. When fed as a mash, diets produced with RM-ground grain improved performance. The effect of grinding was additive to that of pelleting. The interactive effects observed between grinding method and the form of the feed on body weight and feed intake were explained by the higher response to pelleting when grains were ground in HM vs RM. The positive effect of grinding in RM on feed utilization was found to be additive to that of pelleting in all three experiments. The response of females to feed texture was less pronounced than that of males. In males, feeding pellets vs mash increased mortality due to ascites threefold, whereas grinding method had no effect. Females were less susceptible to ascites than males, and feed texture had no effect in this respect. The effects of grinding and pelleting on the gastrointestinal tract segments were additive. The main effects of feed texture were a significant increase in stomach weight and that of its contents following HM grinding and a decrease in these following pelleting, with no interactions between the two. PMID:7603952

  18. Utilisation of chip thickness models in grinding

    Science.gov (United States)

    Singleton, Roger

    Grinding is now a well established process utilised for both stock removal and finish applications. Although significant research is performed in this field, grinding still experiences problems with burn and high forces which can lead to poor quality components and damage to equipment. This generally occurs in grinding when the process deviates from its safe working conditions. In milling, chip thickness parameters are utilised to predict and maintain process outputs leading to improved control of the process. This thesis looks to further the knowledge of the relationship between chip thickness and the grinding process outputs to provide an increased predictive and maintenance modelling capability. Machining trials were undertaken using different chip thickness parameters to understand how these affect the process outputs. The chip thickness parameters were maintained at different grinding wheel diameters for a constant productivity process to determine the impact of chip thickness at a constant material removal rate.. SIZE: 12pt; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-fareast-language: EN-US; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA">Additional testing using a modified pin on disc test rig was performed to provide further information on process variables. The different chip thickness parameters provide control of different process outputs in the grinding process. These relationships can be described using contact layer theory and heat flux partitioning. The contact layer is defined as the immediate layer beneath the contact arc at the wheel workpiece interface. The size of the layer governs the force experienced during the process. The rate of contact layer removal directly impacts the net power required from the system. It was also found that the specific grinding energy of a process is more dependent on the productivity of a grinding process rather than the value of chip thickness. Changes in chip thickness at constant material removal rate result in microscale changes in the rate of contact layer removal when compared to changes in process productivity. This is a significant piece of information in relation to specific grinding energy where conventional theory states it is primarily dependent on chip thickness..

  19. Work index and grinding energy assessment of Dilband iron ore Pakistan

    International Nuclear Information System (INIS)

    Importance of comminution in mineral processing sector is highly acknowledged from energy perspective. In present study an attempt was made to understand the commuting behavior of Dilband iron ore and to compute the grinding energy requirement for production of ultra fine particles up to mesh of liberation. In this regard standard grind ability tests developed by the Chair of Mineral Processing Leoben Austria was used for calculating work index of Dilband iron ore. The grinding tests were conducted in rod and ball mills. The work index value of two feed size fractions with 80% passing at 3800 macro m and 5200 macro m was noted to be 11.85 kwh/t and 9.3 kwh/ton respectively. Ball mill grinding test indicates that dry grinding in open circuit is not efficient and consumes more energy of 88.48kwh/t of ore for grinding 1000/40 macro to 80% <40 macro m size. (author)

  20. Role of abrasion and corrosion in grinding media wear. Volume 1. [Taconite; molybenite

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1986-01-01

    Purpose of this project was to investigate the effect of grinding conditions, e.g., pH, P/sub O/sub 2//, grinding media composition and, in particular, size of mill on the wear rates and wear mechanism for both a molybdenite ore and a magnetic iron ore. This allowed data to be obtained on the correlation of scale-up between small diameter laboratory mills and industrial mills and provided a relatively inexpensive test method to be developed for the selection of grinding media used with different ores. Secondly, the effect of the physico-chemical properties of the slurry on wear mechanism(s) and wear rates was evaluated using various slurry media and additives. Results of this work were aimed at providing information from which a more efficient selection of grinding media and conditions may be made which will reduce the total energy consumed in the grinding of minerals.

  1. A structured approach to the evaluation of the energy requirements of HPGR and SAG mill circuits in hard ore applications

    Scientific Electronic Library Online (English)

    P., Rosario; R., Hall.

    2010-03-01

    Full Text Available The application of high pressure grinding rolls (HPGR) has been growing in the mining industry for the last 10 to 15 years. The major benefits supporting this trend are better energy efficiency, improved grinding capacity, and higher metal recovery in downstream processes such as heap leaching and f [...] lotation. In general there is limited quantitative knowledge on the true benefits of HPGRs relative to SAG mills in comminution, and about which situations one deals with better than the other. This paper will present a structure for comparison of the energy requirements for HPGR versus SAG mill considering complete circuits for comminution of precious and base metals hard ores. The work presented is from the design of four complete circuits based on ore data from two sites.

  2. The Influence of Ball Charge and Media Size Distribution in Grinding Plant

    OpenAIRE

    COSTEA Claudiu Raul; SILAGHI Helga; KOVENDI Zoltan

    2011-01-01

    This paper presents an analysis of theperformances of an mill grinding circuits. This studyrelieve fineness of cement for certain condition, suchare: ball size distribution, charge of grinding media,weight for all balls from the same category. Becausethe size of media has to match the size of materialbeing ground, it is necessary an analysis of these.Finally, some simulation results are shown.

  3. Effects of High Pressure ORE Grinding on the Efficiency of Flotation Operations

    Science.gov (United States)

    Saramak, Daniel; Krawczykowska, Aldona; M?ynarczykowska, 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).

  4. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    International Nuclear Information System (INIS)

    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 oC the heat transfer is controlled by crystalline component.

  5. Electro-chemical grinding

    Science.gov (United States)

    Feagans, P. L.

    1972-01-01

    Electro-chemical grinding technique has rotation speed control, constant feed rates, and contour control. Hypersonic engine parts of nickel alloys can be almost 100% machined, keeping tool pressure at virtual zero. Technique eliminates galling and permits constant surface finish and burr-free interrupted cutting.

  6. 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 company productivity can be improved.

  7. 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.

  8. Dynamics of Entangled Polymeric Fluids in Two-roll Mill studied via Dynamic Light Scattering and Two-color flow Birefringence; 1, Steady flow

    CERN Document Server

    Sanyal, S; Leal, L C; Sanyal, Subrata; Yavich, Dmitry

    2000-01-01

    We present the experimental results on a series of high molecular weight, entangled polystyrene solutions subjected to a ``mixed'' shear and elongational flow-type generated in a co-rotating two-roll mill. For steady-flows as well as for start-up of flows from rest, we used two different optical methods to study the dynamics of entangled polymeric fluids: two-color flow birefringence (TCFB) and dynamic light scattering (DLS). Using the TCFB method, we measured the birefringence, $\\Delta n$, and the orientation angle, $\\chi$, of the optic axes in the solution and thereby the generalized viscosity function, $\\eta$ (with the use of stress-optical relations). The DLS method was applied to measure the velocity-gradient, \\gdot, and the flow-type parameter $\\lambda$ for the polymer solutions under flow conditions identical to the TCFB measurements. For low deformation rates the symmetry of the flow-field was reduced with the use of polymeric fluids compared to that seen with a Newtonian fluid. A molecular constituti...

  9. Adsorption of single-strand alkylammonium salts on bentonite, surface properties of the modified clay and polymer nanocomposites formation by a two-roll mill

    International Nuclear Information System (INIS)

    The adsorption of tallow alkylammonium salts onto bentonite from the Lopburi province in Thailand, and the effect of surface wettability on the formation of polymer-clay nanocomposites are reported. We looked specifically at octadecyltrimethyl ammonium chloride (S18), a popular member of the tallow alkylammonium salt family. The adsorption of S18 onto the bentonite interlayer can be divided into three distinct stages depending upon the initial concentration of S18. These stages are (a) monolayer formation, (b) intermediate state of double layer formation and (c) double layer formation. A decrease in surface energy driven by drops in the values of the polar and dispersive components was observed as the amount of surfactant surface coverage increased. Using thermal gravimetric analysis (TGA), the critical surface energy (CSE) of organoclay was found to decrease as the amount of absorbed S18 increased. S18 organoclay with different degrees of surface coverage was used in a two-roll mill to prepare high-density polyetheylene (HDPE)-clay nanocomposites. The oxidized polyethylene wax (OWax) was used as a dispersing agent to promote the delamination of the organoclay platelets. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated a difference in the dispersing capability of the organoclay.

  10. Adsorption of single-strand alkylammonium salts on bentonite, surface properties of the modified clay and polymer nanocomposites formation by a two-roll mill

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Jumpei [Materials Science and Engineering Programme and Nanotec Center of Excellence at Mahidol University, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Limpanart, Sarintorn; Khunthon, Srichalai [Metallurgy and Materials Research Institute, Chulalongkorn University, Phayathai, Bangkok 10330 (Thailand); Osotchan, Tanakorn [Materials Science and Engineering Programme and Nanotec Center of Excellence at Mahidol University, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Physics Department, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Traiphol, Rakchart [Laboratory of Advanced Polymers and Nanomaterials, Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Naresuan University, Phitsanulok 65000 (Thailand); Srikhirin, Toemsak, E-mail: sctsk@mahidol.ac.th [Materials Science and Engineering Programme and Nanotec Center of Excellence at Mahidol University, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand); Physics Department, Faculty of Science, Mahidol University, Rajathavee, Bangkok 10400 (Thailand)

    2010-10-01

    The adsorption of tallow alkylammonium salts onto bentonite from the Lopburi province in Thailand, and the effect of surface wettability on the formation of polymer-clay nanocomposites are reported. We looked specifically at octadecyltrimethyl ammonium chloride (S18), a popular member of the tallow alkylammonium salt family. The adsorption of S18 onto the bentonite interlayer can be divided into three distinct stages depending upon the initial concentration of S18. These stages are (a) monolayer formation, (b) intermediate state of double layer formation and (c) double layer formation. A decrease in surface energy driven by drops in the values of the polar and dispersive components was observed as the amount of surfactant surface coverage increased. Using thermal gravimetric analysis (TGA), the critical surface energy (CSE) of organoclay was found to decrease as the amount of absorbed S18 increased. S18 organoclay with different degrees of surface coverage was used in a two-roll mill to prepare high-density polyetheylene (HDPE)-clay nanocomposites. The oxidized polyethylene wax (OWax) was used as a dispersing agent to promote the delamination of the organoclay platelets. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated a difference in the dispersing capability of the organoclay.

  11. Assessment of air pollution and its effects on the health status of the workers in beam rolling mills factory (Iran National Steel Industrial Group from Ahvaz-Iran

    Directory of Open Access Journals (Sweden)

    Rafiei Masoud

    2009-01-01

    Full Text Available Background: Air pollutants of iron- and steel-making operations have historically been an environmental and health hazard. These pollutants include gaseous substances such as sulfur oxide, nitrogen dioxide, and carbon monoxide. The Iran National Steel Industrial Group beam rolling mills factory has two production lines viz. line 630 and line 650, with different beam production capabilities and is capable of producing different types of beams. Materials and Methods: A retrospective cross-sectional study on 400 workers in different exposure levels to environmental pollution was performed during 2005 to determine the mean value of respirable particulate matter (RPM concentrations and its effects on the health status of workers. To elicit information regarding the health status of the worker, the National Institute for Occupational Safety and Health standard questionnaire was used. Fisher?s exact test was performed to assess the relative risk (RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers. Results: There was significant difference in RPM pollution level between two product lines. The RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers were 2.78, 2.44, 2.15, 1.92, 1.57, 3.90, and 2.09, respectively.

  12. 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.

  13. ONLINE SAG MILL PULSE MEASUREMENT AND OPTIMIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti

    2006-06-24

    The grinding efficiency of semi autogenous milling or ball milling depends on the tumbling motion of the total charge within the mill. Utilization of this tumbling motion for efficient breakage of particles depends on the conditions inside the mill. However, any kind of monitoring device to measure the conditions inside the mill shell during operation is virtually impossible due to the severe environment presented by the tumbling charge. An instrumented grinding ball, which is capable of surviving a few hours and transmitting the impacts it experiences, is proposed here. The spectrum of impacts collected over 100 revolutions of the mills presents the signature of the grinding environment inside mill. This signature could be effectively used to optimize the milling performance by investigating this signature's relation to mill product size, mill throughput, make-up ball size, mill speed, liner profile and ball addition rates. At the same time, it can also be used to design balls and liner systems that can survive longer in the mill. The technological advances made in electronics and communication makes this leap in instrumentation certainly viable. Hence, the instrumented grinding ball offers the ability to qualitatively observe and optimize the milling environment.

  14. The role of abrasion and corrosion in grinding media wear: Annual technical progress report. [Taconite; molybdenite; quartzite

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1984-06-12

    Aim of this research program is to establish the effect of mill size and batch or continuous operation on the role of corrosive and abrasive wear during mineral grinding operations. Grinding ball wear tests are being conducted on the laboratory, pilot plant and industrial scale. This report gives the results of the first year's work of the two year research program and are discussed under the following headings: Wear Tests in an 8-inch Laboratory Mill (Using Three Different Ball Chemistries for Both Taconite and Molybdenite Ore); Wear Tests in a 36-inch Batch Mill (Using High Carbon Low Alloy Steel Balls with Taconite); Mechanisms of Erosive Wear in Taconite Grinding (Using Mild Steel Balls); The Effect of Slurry Rheology on Grinding Media Wear (Using Mild Steel Balls - Quartzite Combination); and Pilot Plant continuous Grinding Tests (Using High Carbon Low Alloy Steel Balls with Taconite Ore).

  15. Tensile mechanical behavior and fracture toughness of MWCNT and DWCNT modified vinyl-ester/polyester hybrid nanocomposites produced by 3-roll milling

    International Nuclear Information System (INIS)

    This study aims to investigate the tensile mechanical behavior and fracture toughness of vinyl-ester/polyester hybrid nanocomposites containing various types of nanofillers, including multi- and double-walled carbon nanotubes with and without amine functional groups (MWCNTs, DWCNTs, MWCNT-NH2 and DWCNT-NH2). To prepare the resin suspensions, very low contents (0.05, 0.1 and 0.3 wt.%) of carbon nanotubes (CNTs) were dispersed within a specially synthesized styrene-free polyester resin, conducting 3-roll milling technique. The collected resin stuff was subsequently blended with vinyl-ester via mechanical stirring to achieve final suspensions prior to polymerization. Nanocomposites containing MWCNTs and MWCNT-NH2 were found to exhibit higher tensile strength and modulus as well as larger fracture toughness and fracture energy compared to neat hybrid polymer. However, incorporation of similar contents of DWCNTs and DWCNT-NH2 into the hybrid resin did not reflect the same improvement in the corresponding mechanical properties. Furthermore, experimentally measured elastic moduli of the nanocomposites containing DWCNTs, DWCNT-NH2, MWCNTs and MWCNT-NH2 were fitted to Halphin-Tsai model. Regardless of amine functional groups or content of carbon nanotubes, MWCNT modified nanocomposites exhibited better agreement between the predicted and the measured elastic moduli values compared to nanocomposites with DWCNTs. Furthermore, Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to reveal dispersion state of the carbon nanotubes within the hybrid polymer and to examine the CNT induced failure modes that occurred under mechanical loading, respectively. Based on the experimental findings obtained, it was emphasized that the types of CNTs and presence of amine functional groups on the surface of CNTs affects substantially the chemical interactions at the interface, thus tuning the ultimate mechanical performance of the resulting nanocomposites.

  16. Role of abrasion and corrosion in grinding media wear. Volume III

    Energy Technology Data Exchange (ETDEWEB)

    Eggert, J.F.

    1985-01-01

    The relative contributions of abrasion and corrosion and the effect of scale-up on the wear rates of three different grind materials in molybdenite and taconite ore milling under three mill atmospheres was investigated. A standardized marked ball wear test was implemented to obtain reliable and reproducible results from the three mill sizes. The mechanisms responsible for wear were determined through SEM and EDX examinations.

  17. Rolling and annealing texture in twin roll cast commercial purity aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Benum, S. (SINTEF, Div. of Metallurgy, Trondheim (Norway)); Engler, O. (Inst. fuer Metallkunde und Metallphysik, RWTH Aachen (Germany)); Nes, E. (Norwegian Inst. of Tech., Dept. of Metallurgy, Trondheim (Norway))

    1994-01-01

    The development of cold rolling and annealing texture in twin roll cast commercial aluminium has been studied, varying rolling conditions such as lubricant and rolling speed in laboratory rolling and by comparing laboratory rolled sheets to that from a commercial mill. The tendency to formation of shear texture in the surface of laboratory rolled sheets was promoted by high surface friction and low rolling speeds, while well lubricated rolls and high speeds resulted in a plane strain type texture also in the sheet surface. The latter was also typical of industrial rolling. The effect of the surface deformation mode and texture on the grain structure resulting from the subsequent annealing has also been studied. The shear texture in laboratory rolled sheets were associated with a smaller grain size than industrially rolled sheets. (orig.)

  18. Role of abrasion and corrosion in grinding media wear. Volume 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1986-01-01

    Purpose of this project was to investigate the effect of grinding conditions, e.g., pH, P/sub O/sub 2//, grinding media composition and, in particular, size of mill on the wear rates and wear mechanism for both a molybdenite ore and a magnetic iron ore. This allowed data to be obtained on the correlation of scale-up between small diameter laboratory mills and industrial mills and provided a relatively inexpensive test method to be developed for the selection of grinding media used with different ores. Also, the effect of the physico-chemical properties of the slurry on wear mechanism(s) and wear rates was evaluated using various slurry media and additives.

  19. THE CHARACTERIZATION OF GRINDING FORCES

    Directory of Open Access Journals (Sweden)

    E.F. Fielding

    2012-01-01

    Full Text Available Traditionally the grinding process has been a finishing process and the operating parameters and the resuns obtained in this mode are well known. However, wHh the advent of more modern techniques in grinding, there is a need for a greater understanding of the process and in particular a need to be able to predict the forces in grinding. The work reported here is part of an overall programme to study the effects of different dress leads, wheel formulations and metal removal rates on grinding ratios, surlace finish and grinding forces. The work so far has led to the development of empirical relationships based on the various factors in the dressing and grinding operations, these empirical relationships are more easily applied than the relationships developed by other researchers that rely on measurements obtained during testing. The work is now being extended to develop a theoretical derivation on the same principles, the implications of which will be discussed in the paper.

  20. Design of the Soymilk Mill based on TRIZ Theory

    Directory of Open Access Journals (Sweden)

    Jiang Fan

    2013-05-01

    Full Text Available The soymilk mill is an important food machine, but its volume is too large to be suitable for house using. This study first analyzes some problems in the soymilk mill miniaturization. For these problems, the thinking tools, evolutionary tools and contradiction solving tool of TRIZ theory are used to resolve the conflict in the integration of grinding and boiling and in the keep grinding effect, to tackle the optimization problem in the grinding stria structure and mill plate speed, then the Dwarfs method and substance-field analysis model is used in solving the interference and the conditions water supply problems which are encountered in the design of the global structure and a micro soymilk mill is designed. Finally, the mechanical analysis model about soy granules, soymilk particles in the grinding zone and the computational model of motor starting torque are obtained; they provide the reference data for application of soymilk mill.

  1. Large-scale Evaluation of Nickel Aluminide Rolls in a Heat-Treat Furnace at Bethelehem Steel's (Now ISG) Burns Harbor Plate Mill

    Energy Technology Data Exchange (ETDEWEB)

    Mengel, J.

    2003-12-16

    At Bethlehem Steel Burns Harbor Plate Division (now ISG Burns Harbor Plate Inc.)'s annealing furnace, new nickel aluminide intermetallic alloy rolls provide greater high-temperature strength and wear resistance compared to the conventional H series cast austenitic alloys currently used in the industry. Oak Ridge National Laboratory and Bethlehem (ISG) partnered under a U.S. Department of Energy, Office of Industrial Technology's Emerging Technology Deployment Program to demonstrate and evaluate the nickel aluminide intermetallic alloy rolls as part of an updated energy efficient large commercial annealing furnace system. Many challenges were involved in this project, including developing welding procedures for joining nickel aluminide intermetallic alloys with H-series austenitic alloys, developing commercial cast roll manufacturing specifications, working with several commercial suppliers to produce a quantity of high quality, reproducible nickel aluminide rolls for a large steel industrial annealing furnace, installing and demonstrating the capability of the rolls in this furnace, performing processing trials to evaluate the benefits of new equipment and processes, and documenting the findings. Updated furnace equipment including twenty-five new automated furnace control dampers have been installed replacing older design, less effective units. These dampers, along with upgraded flame-safety control equipment and new AC motors and roll-speed control equipment, are providing improved furnace control and additional energy efficiency. Energy data shows up to a 34% energy reduction from baseline after the installation of upgraded furnace damper controls along with up to a 34% reduction in greenhouse gases, potential for an additional 3 to 6% energy reduction per campaign of light-up and shutdown, and a 46% energy reduction from baseline for limited trials of a combination of improved damper control and straight-through plate processing. The straight-through processing is now possible because of the nickel aluminide rolls which also provided plate product surface quality improvement that will allow the additional processing of surface critical material. Benefits also include associated large reductions in maintenance, reduction in spare rolls and associated component costs, and potential for greater through-put and productivity. Estimated project fuel cost reductions alone for processing 100,000 tons/yr through this furnace are almost $0.5 million/yr with the new dampers, and more than $600,000/yr with straight-through processing and new damper control, assuming natural gas prices of $6.00/MMBtu. The nickel aluminide rolls are competitively priced with conventional H series alloy rolls.

  2. Rolling Stonesi kinokontsert kannab toorest rokiväge / Maris Meiessaar

    Index Scriptorium Estoniae

    Meiessaar, Maris

    2009-01-01

    Martin Scorsese muusikalisest dokumentaalfilmist "Shine a Light - Valgus peale" (USA-Suurbritannia, 2008), mille keskmes on 2006. a. New Yorgi Beaconi teatris toimunud briti ansambli Rolling Stones kontsert

  3. Role of abrasion and corrosion in grinding media wear. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1984-01-01

    The effects of slurry rheological properties on the erosive wear of grinding media and grinding efficiency (percent minus 325 mesh) have been studied in a laboratory ball mill using minus 10 mesh quartzite. A laboratory procedure was also utilized to evaluate the tendency for the slurry to coat the grinding media. Media wear decreased continuously with increasing percent solids while grinding efficiency was maximized at 60% solids. Slurry percent solids were found to be the critical factor affecting media wear in high percent solids slurries while other factors such as viscosity were more important at lower percent solids. This was demonstrated by the use of a grinding aid in a 70% solids slurry which resulted in only a small increase in wear (44 to 45.6 mg/ball) despite a significant reduction in viscosity (2359 mPa S at 75 rpm). Slurry relative viscosity was found to control the thickness of the slurry coating the balls which was in turn related in a direct linear manner to media wear. In terms of percent minus 325 mesh, the effects of viscosity and ball coating were in agreement with those presented in the literature. Scanning electron microscopic evaluation of ball surfaces and visual inspection of the movement of the ball charge both tended to support the theory of grinding in ball mills through nipping more so than attrition.

  4. TRISO-coated spent fuel processing using a Grind-Leach head-end

    International Nuclear Information System (INIS)

    Processing of TRISO-coated HTGR fuels with the grind-leach process requires that the fuel be finely pulverized for efficient and effective acid dissolution of the fuel components. Mechanical size reduction of the fuel is being investigated with jet mill technology as the final milling step. Laboratory experiments were performed with surrogates of crushed fuel compacts that indicate that milling to very small particle sizes is feasible. The size distribution of the milled product is sensitive to the solids feed rate, and the distribution may be bimodal which could support an effective solid-solid separation. (author)

  5. Milling media from zirconia ceramics

    International Nuclear Information System (INIS)

    Zirconia ceramics has found applications in various important fields. Oxygen sensors, heating elements, solid electrolytes, cutting tools, high temperature insulation, metal casting dies and nozzles are some of the areas of applications. Milling of zirconia compositions should preferably be done with ZrO2 milling media. Moreover, higher density of ZrO2 (5.5-5.7 gm/cc.) compared to alumina (3.4-3.7 gm/cc) results in faster grinding by zirconia balls. Wear of the grinding jar is also less compared to alumina balls. In the present work grinding balls have been prepared from zirconia, Y2O3, CaO-TiO2 stabilizing agents. (author). 6 refs., 2 figs., 1 tab

  6. 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 wi...

  7. Improved coal grinding and fuel flow control in thermal power plants

    OpenAIRE

    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...

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

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Hansen, Brian Brun

    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 reductions of Danish wheat straw, spruce chips, and pine chips. On the basis of initial experiments, which evaluated the influence of reactor mass loading, gas flow, and grinding ball size and material, a standard experimental procedure was developed. The particle size reduction capability of the torrefaction process has been evaluated by the relative change in d50, and this method was compared to the Hardgrove grindability index (HGI), showing reasonably similar results. Significant differences in torrefaction behavior have been observed for straw and spruce chips torrefied at 270–330 °C. Torrefaction of straw for 90 min yielded a higher mass loss (27–60 wt %) and relative size reduction (59–95%) compared with spruce (massloss 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, 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 a swift grinding of the torrefied biomass. This implies that the rate-limiting step in the laboratory reactor is the heat transfer and not the grinding process. Large pine particles (8–16 mm) showed a slightly higher mass loss than 4–8 and <4 mm particles. This could be the consequence of exothermic reactions in the particle core, which locally increase the temperature and conversion.

  9. Grinding with classification via geometric partition models

    International Nuclear Information System (INIS)

    A grinding process with classification is considered. An integral grinding equation connecting the final particle size distribution function to the particle size distribution function before the grinding process is studied. Geometric partition models are used to obtain the breakage function. The results are compared with experimental data

  10. Ceramic-bonded abrasive grinding tools

    Science.gov (United States)

    Holcombe, C.E. Jr.; Gorin, A.H.; Seals, R.D.

    1994-11-22

    Abrasive grains such as boron carbide, silicon carbide, alumina, diamond, cubic boron nitride, and mullite are combined with a cement primarily comprised of zinc oxide and a reactive liquid setting agent and solidified into abrasive grinding tools. Such grinding tools are particularly suitable for grinding and polishing stone, such as marble and granite.

  11. Thermal study of complex formation of triamterene with ?-cyclodextrin by spray-drying and co-grinding

    OpenAIRE

    Ginés, J.M.; Arias Blanco, M. J.; Novák, C.; Sánchez-Soto, Pedro José; Ruiz Conde, Antonio; Morillo González, Esmeralda

    1995-01-01

    The formation of crystalline inclusion complex of triamterene with ?-cyclodextrin (?-CD) was studied, evaluating the thermal behaviour and dispersion state of this drug in different types of binary systems. Spray-drying and co-grinding (oscillating mill) mixtures of triameterene with ?-CD were prepared in 1:1 molar ratio. The changes of crystalline properties of original (untreated) triamterene, ?-CD, and composites obtained by co-grinding and spray-drying were investigated in comparison with...

  12. Basic grinding research and raising unit capacity. Final report; Hionnan perustutkimus ja yksikkoekapasitettin nosto; Loppuraportti

    Energy Technology Data Exchange (ETDEWEB)

    Karojaervi, R. [Valmet Tampella Oy, Tampere (Finland)

    1993-10-01

    The project looked at ways of improving the energy economy of pressure grinding and the quality of the PGW produced. The biggest improvements, are super-pressure grinding (PGW-S) and the use of low temperatures in pressure grinding. The PGW-S groundwood mill built at Voikkaa in 1990 has produced the expected improvement in pulp strength and paper printing characteristics. Yet specific electrical energy consumption is just as low as in open grinding. Taking all mechanical pulps into account, pressure grinding gave the highest energy efficiency, i.e. pulp strength per unit energy consumption. Calculated in terms of tensile strength, the energy efficiency of PGW-S suitable for demanding printing papers is almost 50 % superior to that of TMP. Lowering the temperature used in pressure grinding produces almost the same pulp strength as in pressure grinding at the normal temperature. However, the pulp had a much smaller coarse fibre fraction, which improves the paper`s surface structure and reduces the tendency towards surface roughening when the paper is coated or printed. The pulp produced by new low-temperature pressure grinding process also has excellent brightness. Pilot-scale trials showed that halving the peripheral speed of the grindstone cuts specific energy consumption by about 15 % and improves the strength of the pulp by some 10 %. The next step is to move up u production scale, when the energy efficiency of pressure grinding can be improved by a further 20-30 %. Ways were also devised to raise the unit capacity of pressure grinders by around 20 %

  13. 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

  14. Force characteristics in continuous path controlled crankpin grinding

    Science.gov (United States)

    Zhang, Manchao; Yao, Zhenqiang

    2015-03-01

    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.

  15. Changes in the properties of coal due to reduction in size in different grinding media. Aenderungen von Kohleneigenschaften durch Zerkleinerungsvorgaenge in unterschiedlichen Mahlmedien

    Energy Technology Data Exchange (ETDEWEB)

    Kammerich, B.

    1988-12-20

    The aim of this work was to examine to what extent the reduction in size of coal in different grinding media (surrounding gases/vapours) is connected with changes in relevant coal properties (strength/resistance to grinding, heat of wetting, saturation loading, calorific value, volatile components, swelling index, swelling etc). The experiments were carried out in a laboratory ball mill made of steel at normal pressure and ambient temperature (20/sup 0/C). The type of coal (1 anthracite, 1 coking coal, 1 gas coal, 2 gas flame coals, 1 flame coal), the grinding medium (air, nitrogen, carbon dioxide, ethanol vapour and methanol vapour) and the duration of grinding (between 15 and 90 minutes) were varied. In addition, some grinding experiments were carried out in a disk mill under an atmosphere of air. The results are discussed with regard to the processes for which the coal is used. (RB).

  16. Grinding assembly, grinding apparatus, weld joint defect repair system, and methods

    Science.gov (United States)

    Larsen, Eric D.; Watkins, Arthur D.; Bitsoi, Rodney J.; Pace, David P.

    2005-09-27

    A grinding assembly for grinding a weld joint of a workpiece includes a grinder apparatus, a grinder apparatus includes a grinding wheel configured to grind the weld joint, a member configured to receive the grinding wheel, the member being configured to be removably attached to the grinder apparatus, and a sensor assembly configured to detect a contact between the grinding wheel and the workpiece. The grinding assembly also includes a processing circuitry in communication with the grinder apparatus and configured to control operations of the grinder apparatus, the processing circuitry configured to receive weld defect information of the weld joint from an inspection assembly to create a contour grinding profile to grind the weld joint in a predetermined shape based on the received weld defect information, and a manipulator having an end configured to carry the grinder apparatus, the manipulator further configured to operate in multiple dimensions.

  17. Surface grinding characteristics of ferrous metals under high-speed and speed-stroke grinding conditions

    International Nuclear Information System (INIS)

    Some ferrous metals have been ground under different conditions with high-speed and speed-stroke in surface grinding operation. The paper describes experimental investigation of grinding forces in grinding some ferrous metals with the application of cutting fluids. Grinding tests have been carried out on mild steel, assab steel and stainless steel with different combinations of down feed and cross feed. The wheel speed was 27 m/sec while the table speed was maintained at the maximum possible 25 m/min. The grindability has been evaluated by measuring the grinding forces, grinding ratio, and surface finish. Grinding forces have been plotted against down feed of the grinding wheel and cross feed of the table. It has been observed that the radial and tangential grinding forces in stainless steel were higher than those in assab steel and mild steel

  18. Production of grinding wheels with high grinding force ratio and high efficiency for glassy materials

    International Nuclear Information System (INIS)

    A new method to produce grinding wheels for glass materials is discussed. The production method maker uses pulsed electric current sintering (PECS). The new grinding wheels were evaluated by influencing factors, such as porosity, grinding forces, grinding pressure, and removal rate. A quick evaluation method of 'reciprocal grinding tests' is developed to estimate grinding ratio. In the reciprocal grinding test, porosity of around 30 % shows the higher grinding force ratio. Apart of cost considerations, to obtain a high grinding ratio with grain size of 12-15 ? m and particle size of cast-iron of 11 ? m, the 30 % grain fraction is better than the 1.5 % and 7.5 % grain fraction. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  19. Enhanced dissolution and bioavailability of raloxifene hydrochloride by co-grinding with different superdisintegrants.

    Science.gov (United States)

    Jagadish, Balasubramaniam; Yelchuri, Rajesh; K, Bindu; Tangi, Hemalatha; Maroju, Swetha; Rao, Vinay Umesh

    2010-03-01

    The present study investigated the effect of co-grinding raloxifene HCL (RHCL) with different superdisintegrants, namely crospovidone (CP), croscarmellose sodium (CCS) and sodium starch glycolate (SSG), using a ball mill, in order to determine the potential effect on dissolution rate and bioavailability of raloxifene hydrochloride (RHCL). The dissolution studies of the co-ground compositions and the corresponding physical mixtures were carried out in U.S. Pharmacopeia (USP) Type II apparatus. The solid state interactions of the co-ground and the physical mixtures were evaluated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The pharmacokinetics of co-ground mixture (1 : 5 RHCL : CP) and milled RHCL was evaluated following oral administration (25 mg/kg) in healthy female Sprague-Dawley rats. DSC studies showed that the crystalline nature of RHCL was reduced after co-grinding with superdisintegrants, while co-grinding with CP resulted in significant particle-size reduction of the mixture. Significant enhancement in dissolution rate was observed with co-ground mixture of RHCL with CP (1 : 5). The extent of the mean plasma exposures of RHCL was 7-fold higher in animals treated with co-ground mixture of RHCL, CP (1 : 5) compared to animals treated with milled RHCL. Co-grinding of RHCL with CP, reduced drug crystallinity, increased the rate and extent of dissolution, and improved bioavailability. PMID:20190431

  20. Grinding tool optimization in computer controlled grinding of SiC aspheric mirror

    Science.gov (United States)

    Song, Ci; Lu, Yi; Peng, Yanglin

    2014-11-01

    The shape, size and material of grinding tool not only affect the machining accuracy, but also the machining efficiency in the process of Computer Controlled Grinding. The hardness of the SiC aspheric mirror, the misfit of grinding tool and the work-piece also emphasize the importance of grinding tool optimization. By means of analyzing the misfit property of grinding tool and aspheric optic theoretically, as well as the wear character and the process of the grinding tool experimentally, this manuscript establishes the rule of grinding tool optimization satisfying different machining objective. Based on this, the adopted grinding tool was optimized in the grinding process of SiC off-axis aspheric (634mm×560mm). The simulation provide reasonable grinding tool for the off-axis aspheric grinding, and good results (large amount material removal and edge error figuring) are obtained when the optimized grinding tool are applied. Both of the simulations and experiments demonstrate the feasibility and correctness of the grinding tool optimization method.

  1. Online SAG Mill Pluse Measurement and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti

    2007-06-30

    The grinding efficiency of semi autogenous milling or ball milling depends on the tumbling motion of the total charge within the mill. Utilization of this tumbling motion for efficient breakage of particles depends on the conditions inside the mill. However, any kind of monitoring device to measure the conditions inside the mill shell during operation is virtually impossible due to the severe environment presented by the tumbling charge. An instrumented grinding ball, which is capable of surviving a few hours and transmitting the impacts it experiences, is proposed here. The spectrum of impacts collected over 100 revolutions of the mills presents the signature of the grinding environment inside mill. This signature could be effectively used to optimize the milling performance by investigating this signature's relation to mill product size, mill throughput, make-up ball size, mill speed, liner profile and ball addition rates. At the same time, it can also be used to design balls and liner systems that can survive longer in the mill. The technological advances made in electronics and communication makes this leap in instrumentation certainly viable. Hence, the instrumented grinding ball offers the ability to qualitatively observe and optimize the milling environment. An instrumented load cell package that can measure the force of impacts inside the grinding chamber of a mill is developed here. The signal from the instrumented load cell package is interpreted in terms of a histogram termed as an impact spectrum which is a plot of the number of impacts at a specific energy level against the energy. It reflects on the average force regime of the mill. The instrumented load cell package was calibrated against the ultra fast load cell which has been unanimously accepted as a standard to measure single breakage events. The load cell package was successfully used to produce impact spectra in an 8.5 inch lab scale mill. The mill speed and the ball size were varied to study their effect on the impact spectra. A good correlation was found between the process variables and the impact spectra. The load cell package was then used in a 16 inch pilot scale mill. The mill speed, ball size, and mill filling were varied here and a consistent trend between these variables and impact spectra was observed. With a better understanding developed from the initial tests, the design of the load cell package was significantly changed to eliminate noise. With the new design, the impact spectra were re-determined in the 16 inch pilot mill varying the process variables - ball size, mill speed, and mill filling. Finally, it is successfully shown that a change in the operating variables of a mill can be seen in the impact spectra and that this concept can be successfully developed to monitor the grinding operation of industrial mills. To adapt it to industrial level it is mandatory to make the load cell package wireless. A design of a wireless circuit that is capable of transferring data at the required speed of 1000 kbps was also developed and tested at Cortez Gold Mines (CGM), Nevada.

  2. Maximizing wear resistance of balls for grinding of coal

    Energy Technology Data Exchange (ETDEWEB)

    Eduardo Albertin; Sandra Lucia de Moraes [Technological Research Institute (IPT) of the State of Sao Paulo, Sao Paulo (Brazil)

    2007-09-15

    A Brazilian power plant consumes mineral coal with high ash contents to feed four turbines to generate 450 MW. Four ball mills, 4.2 m in diameter, are fed with crushed coal to deliver the material ground to sizes less than 0.075 {mu}m. High wear rates were observed when using forged high-carbon steel balls. A pilot-plant ball mill, with a 0.01 m{sup 3} chamber, was used to perform wear tests, comparing the original ball material and seven grades of high chromium cast irons, grinding the same coal as used in the industrial plant. Test pieces were 60-mm balls with different chemical compositions and heat treatments. Balls were weighed after 10-h grinding periods, for up to 7 periods. The mass losses were converted to equivalent diameter losses and regression straight lines were obtained, showing the wear rates of the materials. The wear rates of the cast irons with 25-30% Cr were only 10-20% of the wear rate of the forged steel. Cast irons with 15-18% Cr wore at around 50% of the rate of the steel. Analyses of the coal ashes showed around 40% of quartz as 10-20 {mu}m particles. Examination of the surface of worn balls showed that these particles caused the wear.

  3. Spray Rolling Aluminum Strip for Transportation Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kevin M. McHugh; Y. Lin; Y. Zhou; E. J. Lavernia; J.-P. Delplanque; S. B. Johnson

    2005-02-01

    Spray rolling is a novel strip casting technology in which molten aluminum alloy is atomized and deposited into the roll gap of mill rolls to produce aluminum strip. A combined experimental/modeling approach has been followed in developing this technology with active participation from industry. The feasibility of this technology has been demonstrated at the laboratory scale and it is currently being scaled-up. This paper provides an overview of the process and compares the microstructure and properties of spray-rolled 2124 aluminum alloy with commercial ingot-processed material

  4. Failure Analysis of Rollers in mill stand using Failure mode Effect Analysis

    OpenAIRE

    Tadisetti Premsai; Anga Kiran Vikram; Varma, S.Sivarajan

    2014-01-01

    Rolling is an important steel production process. Productivity and quality improvements in metal rolling are possible by paying a detailed attention to the various roll failure modes.A proper understanding of the causes of roll failure modes is usually complex and depends on the metallurgical quality of rolls, improper mill usage practices and abnormal rolling conditions. The work rolls operate under severe condition and should posses excellent wear resistance and very little ...

  5. Lathe converted for grinding aspheric surfaces

    Science.gov (United States)

    Larmer, J. W.; Levinsohn, M.; Mc Craw, D.; Pessagno, E. H.; Taub, F. J.

    1964-01-01

    A standard overarm tracing lathe converted by the addition of an independently driven diamond grinding wheel is used for grinding aspheric surfaces. The motion of the wheel is controlled by the lathe air tracer following the template which produces the desired aspheric profile.

  6. 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).

  7. Theoretical considerations of machining with grinding wheels

    Directory of Open Access Journals (Sweden)

    Andrew Oyakhobo Odior

    2013-03-01

    Full Text Available Grinding is one of the most versatile methods of removing material from machine parts by the cutting action of the countless hard and sharp abrasive particles of a revolving grinding wheel. It works by forcing the abrasive grains into the surface of the workpiece so that each grain cuts away a small bit of material in the form of chips. Abrasive grinding wheel is an expendable wheel that carries an abrasive compound on its periphery. They are made of small, sharp and very hard natural or synthetic abrasive minerals, bonded together in a matrix to form a wheel. The paper presents a review of some of the characteristics as well as theoretical considerations of operations of abrasive grinding wheel. The relationships among the various grinding parameters; the radial force f, the force on individual grit of grinding wheel F, velocity of grinding wheelg Vg, velocity of work piecew Vw, the wheel diameterg Dg, and the diameter of the work piece Dw were established for given grinding operations.

  8. The analysis of the asymmetric plate rolling process

    Directory of Open Access Journals (Sweden)

    A. Kawa?ek

    2007-08-01

    Full Text Available Purpose: The analysis of asymmetric band rolling in the finishing stand of a plate rolling mill has been carried out within the present study with the aim of establishing the effect of the speed asymmetry factor, av, on band bending during the rolling process and determining the strain velocity distributions of the rolled material in the roll bite region.Design/methodology/approach: The simulation of metal flow in the asymmetric roll bite region was performed using the program FORGE 2D. The development of numerous branches of the steelmaking industry imposes increasingly high demands on steel product manufacturers, which can only be met by products manufactured according to the state-of-the-art plastic working technologies. One of the major plastic working technologies is asymmetric rolling.Findings: The analysis shows that the band bends most often toward the lower-speed roll. Increasing the value of the speed asymmetry factor causes an increase in the advance, while the force parameters decrease with increasing asymmetry factor av.Practical implications: Asymmetric rolling is achieved by differentiating working roll diameters, roll rotational speeds, or roll surface roughness. In industrial practice, one or a combination of the above-mentioned parameters is used.Originality/value: In order to improve the asymmetric plate rolling process, the analysis of the following parameters must be carried out: band temperature, the magnitude of rolling reduction, the magnitude of yield stress for particular steel grades, roll rotational speeds and roll diameters.

  9. Grinding induced martensite on the surface of rails

    DEFF Research Database (Denmark)

    Rasmussen, C.J.; Zhang, Xiaodan

    2014-01-01

    Rolling contact fatigue (RCF) is causing crack initiation and crack propagation in rails. Some types of RCF cracks are found to be associated with a white etching layer (WEL). A metallurgical investigation was carried out on a worn rail and the amounts of WEL at different positions on the rail were 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.

  10. Analysis of the bimetallic bars rolling during a skew rolling

    Directory of Open Access Journals (Sweden)

    S. Sawicki

    2008-07-01

    Full Text Available Purpose: Bimetallic bars which possess higher corrosion resistance and mechanical properties, it is the newkind of bimetallic bars which are better than standard bars. The bimetallic bars are more often applied in concreteconstruction. There are few methods which ensure a good strength of bimetallic layer bond. Hydrostatic extrusion,rotary rolling and explosive cladding are most often used methods.Design/methodology/approach: The simulations of the bar rolling in a three-high skew mill were carriedout using the Forge2005® commercial program.Findings: The higher value of yield stress of the cladding layer does not produce the effect of “flowing down” ofthis layer over the core surface and it’s folding between the rolls. The use of non-corrosive steel on plating layerassures receipt on a high durability and esthetics bimetallic bars.Practical implications: Bimetallic bars are chiefly used in the building industry at production of concreteconstructions, and as working elements in bridge building in aggressive environment.Originality/value: Production of bimetallic bars is very difficult. One from many problems during productionbimetallic bars is assurance good strength of bimetallic layer bond. A theoretical analysis of bimetallic bar rollingin a three-high skew mill is presented in the paper and the distributions of stress and strain intensities in thebimetallic bar during skew rolling are shown.

  11. 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

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

    Scientific Electronic Library Online (English)

    Eraldo Jannone da, Silva; Eduardo Carlos, Bianchi; João Fernando Gomes de, Oliveira; Paulo Roberto de, Aguiar.

    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 st [...] ress 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.

  13. 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.

  14. The effect of processing parameters on energy consumption of ball mill refiner for chocolate

    OpenAIRE

    Fišteš Aleksandar Z.; Raki? Dušan Z.; Pajin Biljana S.; Doki? Ljubica P.; Nikoli? Ivana R.

    2013-01-01

    A laboratory ball mill consisting of vertical cylinder, equipped with a rotating shaft with arms, and filled with steel balls as a grinding medium has been used in the experiments. The aim of the study was to examine the effect of agitator shaft speed and amount of grinding media (steel balls) on power requirements and energy consumption of a ball mill. With constant mass of the steel balls (20 kg, 30 kg and 40 kg), the agitator shaft speed was increased fr...

  15. Effects of dry grinding on pyrolliphyte

    OpenAIRE

    Pérez Rodríguez, José Luis; Madrid, Luis; Sánchez-Soto, Pedro José

    1988-01-01

    Dry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle size were detected by SEM and XRD, resulting in a large increase in specific surface area, up to a maximum of ~ 60 m 2 . g-1. Marked changes in the structure take place betw...

  16. The grinding of uranium dioxide from fluidized beds

    International Nuclear Information System (INIS)

    This work deals with the UO2 vibratory grinding, the UO2 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 UO2 are outlined. Finally it is made a brief study of the granulate obtained from the grinded UO2 as well as the green pellets resulting from it, taking into consideration the dispersion of its density and height. (Author)

  17. Separation of P Phase and Fe Phase in High Phosphorus Oolitic Iron Ore by Ultrafine Grinding and Gaseous Reduction in a Rotary Furnace

    Science.gov (United States)

    Gao, Jintao; Guo, Lei; Guo, Zhancheng

    2015-10-01

    Due to the oolitic structure of the high phosphorus iron ore and the closely wrapping of apatite and hematite phases, an approach using jet mill was utilized to grind the ore to ultrafine 0.01 to 0.001 mm, which realizes the dissociation of apatite phase and hematite phase. Then in a laboratory scale rotary furnace, high phosphorus ores of different sizes were reduced by reducing gas at sub-melting point temperatures (973 to 1173 K [700 to 900 °C]). In the rotating inclined reactor, the ore particles reacted with the reducing gas coming from the opposite direction in a rolling and discrete state, which greatly improved the kinetic conditions. In this study, the reaction rate increases significantly with the decrease of particle size. For the ultrafine high phosphorus iron ores, the metallization ratio can reach 83.91 to 97.32 pct, but only 33.24 to 40.22 pct for powders with the size of 0.13 to 0.15 mm. The reduced particles maintained their original sizes, without the presence of sintering phenomenon or iron whisker. Hence, two kinds of products were easily obtained by magnetic separation: the iron product with 91.42 wt pct of Fe and 0.19 wt pct of P, and the gangue product with 13.77 wt pct of Fe and 2.32 wt pct of P.

  18. Studying conditions in the grinding zone. Final report; Hiontavyoehykkeen olojen tutkimus; Loppuraportti

    Energy Technology Data Exchange (ETDEWEB)

    Lucander, M.

    1993-10-01

    One aim of the project was to investigate the effect of the surface temperatures of wood and stone in the grinding zone on production rate, specific energy consumption and the papermaking properties of the pulp. Another aim was to find new grinding materials and to study their suitability for groundwood production. The most important results were 1. A system was developed for measuring the temperature and vibration of the wood close to the grinding zone. The information obtained can be used to describe the state of the wood before defibration. 2. Reducing the flow of shower water onto the stone during pressure grinding allowed the temperature in the grinding zone to be raised. This led to pulp with lower freeness and greater strength. The production rate increased by 20 %. Groundwood strength characteristics could be developed more rapidly by raising the shower water temperature. 3. Extending the length of the infeed magazine allowed the temperature in the grinding zone to be raised and increased the strength of PGW by up to a third. 4. At the same specific energy consumption, the metal cylinder produced groundwood with greater tear strength than that obtained with a traditional ceramic stone. Raising the process temperature brought an improvement of up to 50 % in the tear strength of groundwood produced using the metal cylinder. From the results, it would appear that the use of a metal cylinder in production of super-pressure groundwood (PGW-S) would give a clear competitive edge over thermomechanical pulping (TMP). The production costs for SC paper would be lower with PGW-S, and at the same time electricity costs in mechanical pulping could be cut by around FIM 20 million a year at a 200,000 t/a SC paper mill

  19. A study of ball milling of powdered nuclear oxides

    International Nuclear Information System (INIS)

    The nuclear fuel named MOX, Mixed Oxide Fuels, composed of about 3% to 10% of plutonium oxide in uranium allows to recycle plutonium in Pressurized Water Reactors Fuel performances and recycling are strongly connected with the homogeneity of the (U, Pu)O2 solid solution. Because of the low U and Pu cations interdiffusion during sintering, the quality of the mixing of the uranium and plutonium oxides powders obtained by dry ball milling conditions the homogeneity of the MOX fuel. This study contributes to a better understanding of this key step of the fuel fabrication process. The first part of this work deals with the objectives of the study, that is the maximum PuO2 and UO2 particles sizes that are acceptable after the milling operation as far as they will be resorbed by sintering. The second part investigates the micronizing of powders. The grinding mechanisms involved in the ball mill and their effect on the fragmentation of each single powder are analyzed. The third part concludes with the examination of the grinding/mixing of UO2 + CeO2 powders (cerium oxide powder simulates plutonium oxide) with the adjustment of a characterization technique on green pellets of the co-milled mix. This technique allows to evaluate the efficiency of the grinding/mixing by quantifying CeO2 particles size and their distribution in the mix as a function of grinding time, media size and rotational speed on the ball mill. Even with the most severe grinding conditions (increase of rotational speed or decrease of media size), a number of UO2 particles of size larger than the critical size acceptable after the grinding operation still persists. In contrast, from 2 h of grinding, the corresponding fraction associated with CeO2 particles does not exist. Therefore the penalizing parameter for the homogenization is not the PuO2 (CeO2) particles size, but rather that of UO2 aggregates. (author)

  20. SASS Applied to Optimum Work Roll Profile Selection in the Hot Rolling of Wide Steel

    Science.gov (United States)

    Nolle, Lars

    The quality of steel strip produced in a wide strip rolling mill depends heavily on the careful selection of initial ground work roll profiles for each of the mill stands in the finishing train. In the past, these profiles were determined by human experts, based on their knowledge and experience. In previous work, the profiles were successfully optimised using a self-organising migration algorithm (SOMA). In this research, SASS, a novel heuristic optimisation algorithm that has only one control parameter, has been used to find the optimum profiles for a simulated rolling mill. The resulting strip quality produced using the profiles found by SASS is compared with results from previous work and the quality produced using the original profile specifications. The best set of profiles found by SASS clearly outperformed the original set and performed equally well as SOMA without the need of finding a suitable set of control parameters.

  1. The significance of grinding environment on the flotation of UG2 ores

    Scientific Electronic Library Online (English)

    C.J., Greet.

    2009-01-01

    Full Text Available A large body of work exists discussing the impact of grinding media on mineral flotation. Generally, the work indicates that a change to a less electrochemically active grinding environment has positive benefits on downstream processing. There is a fear, however, that these benefits may not be reali [...] zed when treating low sulphide containing ores, typified by UG2 style deposits. A series of experiments was developed to test the flotation response of UG2 ores using the Magotteaux Mill® to determine if measurable differences in the pulp chemistry could be discerned using a range of grinding media types. Further, the flotation responses of the contained sulphides (chalcopyrite, pentlandite and pyrrhotite) were determined. The data collected provided strong evidence that the grinding environment can significantly influence the pulp chemistry and flotation characteristics of all sulphide minerals, even when the ore contains less than 0.5 per cent total sulphide. The results show that the change to an inert media type produced a substantial improvement in the flotation rate of all sulphide minerals, as well as the PGMs.

  2. 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.

  3. Transverse cylindrical grinding of a eutectic alloy

    Scientific Electronic Library Online (English)

    E. C., Bianchi; V. L., Vargas; T. C., Magagnin; R. D., Monici; O., Vicari Filho; P. R. de, Aguiar; E. Jannone da, Silva.

    2003-03-01

    Full Text Available We report herein on a comparison of the performance of two different grinding wheels (conventional and CBN) in the transverse cylindrical grinding of a eutectic alloy. Three cutting conditions were tested: rough, semi-finishing and finishing. The parameters of evaluation were the cutting force, roug [...] hness and wheel wear. The optimal cutting force and roughness values were obtained when grinding with the conventional wheel, due to the superior dressing operation performed under every cutting condition tested. Although the CBN wheel presented the best G ratio values, they were lower than expected owing to the inappropriate dressing operation applied. Excessive wheel corner wear was detected in both wheels, caused by the grinding kinematics (transverse grinding) employed. In terms of cutting force and roughness, the conventional wheel proved to be the better choice under the conditions tested. However, in terms of the G ratio, a cost analysis is crucial to determine whether the differences between the wheels justify the use of the CBN wheel, in which case the dressing operation requires improvement.

  4. Delamination of hexagonal boron nitride in a stirred media mill

    International Nuclear Information System (INIS)

    A scalable process for delamination of hexagonal boron nitride in an aqueous solution of the non-ionic surfactant TWEEN85 using a stirred media mill is presented. The size of the ZrO2 beads used as grinding media governs the dimensions of the ground boron nitride particles as atomic force microscopic investigations (AFM) reveal: the mean flakes thickness decreases from 3.5 to 1.5 nm and the ratio between mean flake area and mean flake thickness increases from 2,200 to 5,800 nm if the grinding media size is reduced from 0.8 to 0.1 mm. This result shows that a high number of stress events in combination with low stress energy (small grinding media) facilitate delamination of the layered material whereas at high stress energies in combination with a low number of stress events (large grinding media) breakage of the layers dominates over delamination. The results of particle height analyses by AFM show that few-layer structures have been formed by stirred media milling. This result is in agreement with the layer thickness dependence of the delamination energy for hexagonal boron nitride. The concentration of nanoparticles remaining dispersed after centrifugation of the ground suspension increases with grinding time and with decreasing grinding media size. After 5 h of grinding using 0.1 mm ZrO2 grinding media the yield of nanoparticle formation is about 5 wt%. The nanoparticles exhibit the typical Raman peak for hexagonal boron nitride at 1,366 cm?1 showing that the in-plane order in the milled platelets is remained.

  5. Studying possibilities to improve the functional properties of metallurgical rolls

    OpenAIRE

    Z. Stradomski; A. Pirek; Stachura, S

    2008-01-01

    Thc paper prcscnts rcsults nT invcst igations and at~thors' opinion on improving functional propcrtics of mciall urgicnl rolls cast fromGZOOCrMoNi 4-9-3 cast wccl. onc nf most oftcn ilscd lor rolls in scction mills. Thcsc mills Icn~urcq uickcr than flat rolls wear or 1001'spass. whar rcquircs morc Crcqocnt rcpcncr;lt ion. 'Thc machining rcquircs n rclat ivcly low hardness, which is cnsurcd hy ~ h pcc arliiic matrixof casr steel strldid. 7 % ~au thors silggcst 10 achicvc thc optimisntion o f t...

  6. Vibration characteristics analysis of a 20-high Sendzimir mill with localized defect on the working roller

    International Nuclear Information System (INIS)

    The working roller associating with local defect of the twenty-high roll mill not only significantly affects the mill performance, but also reduces surface quality of the strip steel. In this paper, the roll mill model with local defect on the working roller is established. The dynamic rolling process is simulated using the Finite Element Analysis. Effects of the local defect on the vibration characteristics of the roll mill and the surface quality of the strip steel are presented. The calculated results are validated using experimental data.

  7. Microwave-assisted grinding of metallurgical coke

    International Nuclear Information System (INIS)

    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)

  8. Effect of deep cryogenic treatment on the microstructure and wear performance of Cr-Mn-Cu white cast iron grinding media

    Science.gov (United States)

    Vidyarthi, M. K.; Ghose, A. K.; Chakrabarty, I.

    2013-12-01

    The phase transformation and grinding wear behavior of Cr-Mn-Cu white cast irons subjected to destabilization treatment followed by air cooling or deep cryogenic treatment were studied as a part of the development program of substitute alloys for existing costly wear resistant alloys. The microstructural evolution during heat treatment and the consequent improvement in grinding wear performance were evaluated with optical and scanning electron microscopy, X-ray diffraction analysis, bulk hardness, impact toughness and corrosion rate measurements, laboratory ball mill grinding wear test etc. The deep cryogenic treatment has a significant effect in minimizing the retained austenite content and converts it to martensite embedded with fine M7C3 alloy carbides. The cumulative wear losses in cryotreated alloys are lesser than those with conventionally destabilized alloys followed by air cooling both in wet and dry grinding conditions. The cryotreated Cr-Mn-Cu irons exhibit comparable wear performance to high chromium irons.

  9. 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.

  10. Energy requirement for fine grinding of torrefied wood

    Energy Technology Data Exchange (ETDEWEB)

    Repellin, Vincent; Govin, Alexandre; Guyonnet, Rene [Department of Powder and Multi-Components Materials (PMMC), SPIN Research Center, Ecole des Mines de Saint Etienne (EMSE), 158 Cours Fauriel, F-42023 Saint-Etienne (France); Rolland, Matthieu [Process Developments and Engineering Division, Chemical Engineering Department, Institut Francais du Petrole (IFP-Lyon), F-69390 Vernaison (France)

    2010-07-15

    The purpose of this study is to investigate the influence of torrefaction on wood grinding energy. Wood chips were torrefied at different temperatures and durations. The energy required to obtain fine powder was measured. Particle size analyses were carried out on each powder sample. It is showed that torrefaction decreases both grinding energy and particle size distribution. A criterion to compare grindability of natural and torrefied wood is proposed. It takes into account both grinding energy and particle size distribution. It accounts the energy required for grinding particles to sizes inferior to 200 {mu}m, for given grinding conditions. Torrefaction is characterised by the anhydrous weight loss (AWL) of wood. For AWL inferior to around 8%, grinding energy decreases fast. Over 8%, grinding energy decreases at a slow rate. Particle size distribution decreases linearly as the AWL increases. Both for spruce and beech, the grinding criterion is decreased of 93% when the AWL is around 28%. (author)

  11. Critical review of Nanofluid Minimum Quantity Lubrication for Grinding application

    Directory of Open Access Journals (Sweden)

    Mr. Prashant J. Patil,

    2014-08-01

    Full Text Available In recent years, the environment has become one of the most important subject. Emulsion-based cooling fluids are used in grinding for a variety of reasons such as improving surface finish, wheel life, flushing away chips, reducing workpiece thermal deformation. Due to large fluid delivery an extensive amount of mist is generated during grinding process. The workers who breathe in this hazardous mist is having health hazard. There are two alternative for large cutting fluids. One is dry grinding and another is near dry grinding also known as minimum quantity lubrication. MQL grinding refers to the delivery of minute quantity of fluid via an aerosol to the grinding zone. The typical flow rate of grinding fluid for MQL fluid consumption is generally 20-100 ml/hour. Although numerous advantages were found for MQL grinding compared with the conventional technique and dry grinding. The cooling and lubrication performance of the grinding fluid is the key technical area for the success application of MQL grinding process. Nanofluid has emerged as a promising solution to this problem. Nanofluid is a new class of fluids engineered by dispersing nanometer-size solid particles into base fluids such as water, lubrication oils. The excellent properties of the nanofluid makes very attractive in cooling and lubricating application in manufacturing. . This study provides a review of research in this field with focus on use of nanofluids in grinding applications.

  12. 30 CFR 57.14115 - Stationary grinding machines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral...

  13. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines; protective devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other...

  14. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines; protective... OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped...

  15. Adaptive Automatic Gauge Control of a Cold Strip Rolling Process

    OpenAIRE

    ROMAN, N.; E. Ceanga; BIVOL, I.; CARAMAN, S.

    2010-01-01

    The paper tackles with thickness control structure of the cold rolled strips. This structure is based on the rolls position control of a reversible quarto rolling mill. The main feature of the system proposed in the paper consists in the compensation of the errors introduced by the deficient dynamics of the hydraulic servo-system used for the rolls positioning, by means of a dynamic compensator that approximates the inverse system of the servo-system. Because the servo-system is considered va...

  16. Physicochemical and grinding characteristics of dragonhead seeds

    Science.gov (United States)

    Dziki, D.; Mi?, A.; G?adyszewska, B.; Laskowski, J.; Kwiatkowski, S.; Gawlik-Dziki, U.

    2013-12-01

    The results of investigations on the physicochemical and grinding characteristics of Moldavian dragonhead seeds are presented. The data obtained showed that the physical properties (average size, sphericity, surface area, 1 000 seed mass, dynamic angle of repose, coefficient of static friction, and bulk and true densities) of the white and blue form of dragonhead seeds were not significantly different. Both forms of dragonhead showed similar levels of protein (average of 21%), whereas the blue form of dragonhead had a lower fat content (average of 23.1%) and higher mucilage content (13.35%) in comparison to the blue form of seed (24.6 and 9.95%, respectively). Antioxidant capacity of dragonhead seeds was comparable for both forms and averaged about 40%, which corresponded to EC50 values of 0.12 and 0.13 mgml-1 for the white and blue forms, respectively. The grinding material showed similar particle size distribution of ground material for both forms of dragonhead seeds. The lowest values of specific grinding energy were obtained for the white form of dragonhead seeds, those for the blue form were significantly higher. Grinding of dragonhead seeds using a screen 2.0 mm mesh size caused screen hole clogging. This problem did not occur when dragonhead seeds were mixed with wheat grain.

  17. Precision replenishable grinding tool and manufacturing process

    Science.gov (United States)

    Makowiecki, D.M.; Kerns, J.A.; Blaedel, K.L.; Colella, N.J.; Davis, P.J.; Juntz, R.S.

    1998-06-09

    A reusable grinding tool consisting of a replaceable single layer of abrasive particles intimately bonded to a precisely configured tool substrate, and a process for manufacturing the grinding tool are disclosed. The tool substrate may be ceramic or metal and the abrasive particles are preferably diamond, but may be cubic boron nitride. The manufacturing process involves: coating a configured tool substrate with layers of metals, such as titanium, copper and titanium, by physical vapor deposition (PVD); applying the abrasive particles to the coated surface by a slurry technique; and brazing the abrasive particles to the tool substrate by alloying the metal layers. The precision control of the composition and thickness of the metal layers enables the bonding of a single layer or several layers of micron size abrasive particles to the tool surface. By the incorporation of an easily dissolved metal layer in the composition such allows the removal and replacement of the abrasive particles, thereby providing a process for replenishing a precisely machined grinding tool with fine abrasive particles, thus greatly reducing costs as compared to replacing expensive grinding tools. 11 figs.

  18. Research on high precision centering assembly method of roll edge optical elements

    Science.gov (United States)

    Liu, Hua; Liu, Xiaomei

    2015-08-01

    In order to improve the imaging quality of target imaging optical system, in the special environment of large temperature difference, the centering assembly precision of roll edge optical elements was studied. According to the hole-axis coordinate error theory of mechanics, by analyzing the factors affected the precision of mechanical heating surface, combining with the existing method to eliminate error and centering assembly process, a new kind of high precision centering assembly method was put forward. Using additional grinding device to grinding roll edge of optical element, eliminate the machining error on the surface of the mechanical hot working, thus improve the centering assembly precision between the roll edge optical element and lens tube. The result of experiment shows that the centering precision can reach less than 3?m when assembled optical element after roll edge using new centering assembly method, and improved by 25% compared to the traditional method of roll edge optical elements are assembled directly after hot working. New assembly method with additional grinding device can improve the centering assembly precision of roll edge optical elements, and greatly reduce the difficulty of optical design of such optical imaging system using in large temperature difference environment, when meet the same image quality.

  19. Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

    OpenAIRE

    M. Drobne; Vuherer, T.; I. Samardži?; S Glodež

    2014-01-01

    Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for roll’s shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens – SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture...

  20. High pressure grinding moving ahead in copper, iron, and gold processing

    Scientific Electronic Library Online (English)

    F.P., van der Meer; W., Maphosa.

    2012-07-01

    Full Text Available High pressure grinding roll (HPGR) technology is used in an increasingly diverse range of applications, predominantly iron ore , gold and diamonds. KHD Humboldt Wedag HPGRs are applied world-wide, and consistently prove to be well designed and reliable operating units, with their performance meeting [...] the pre-set standards. This publication summarizes some of the features and experiences for recent applications in treatment of copper ore, coarse iron ore, and gold ore. Summary data of roll surface wear life and operating data are given, together with operational observations. In addition, effects of feed segregation and truncated feed are discussed, as well as the implications of a product recycle flow sheet.

  1. Study of texture, microstructure and mechanical properties of asymmetrically rolled aluminium

    Science.gov (United States)

    Wronski, M.; Wierzbanowski, K.; Wronski, S.; Bacroix, B.; Wróbel, M.; Uniwersa?, A.

    2015-04-01

    Asymmetric rolling is a promising forming technique offering numerous possibilities of material properties modification and the improvement of technological process parameters. This geometry of deformation is relatively easy to implement on existing industrial rolling mills. Moreover, it can provide large volume of a material with modified properties. The study of microstructure, crystallographic texture and mechanical properties of asymmetrically rolled aluminium is presented in this work. The above characteristics were examined using EBSD technique and X-ray diffraction. The rolling asymmetry was realized using two identical rolls, driven by independent motors, rotating with different angular velocities. It was found that asymmetric rolling leads to microstructure refinement, texture homogenization and decreasing of residual stress.

  2. Mathematical Aspect for Worm Grinding Using a Toroidal Tool

    Directory of Open Access Journals (Sweden)

    Tareq A. Abu Shreehah

    2004-01-01

    Full Text Available This paper is an attempt to improve the accuracy of the worm gearings with concave profile of the worm thread by using a new generating surface of grinding wheel to eliminate the lacks of the popular worm gearings and extensioning the field of investigation. The present study propose grind concave profile worms by means of toroidal tool - grinding wheel which section in the axial plane is an arc of parabola. The generating equation of the grinding wheel surface and the arrangement of this wheel with respect to the worm during grinding of its thread was determined.

  3. Optimal sizing, scheduling and shift policy of the grinding section of a ceramic tile plant

    OpenAIRE

    Duarte, Belmiro P. M.; Santos, Lino O.; Mariano, Jorge S.

    2008-01-01

    This paper addresses the optimal design of the grinding section of a ceramic tile plant operating in a cyclic mode with the units (mills) following a batch sequence. The optimal design problem of this single product plant is formulated with a fixed time horizon of one week, corresponding to one cycle of production, and using a discrete-time resource task network (RTN) process representation. The size of the individual units is restricted to discrete values, and the plant operates with a set o...

  4. Quantifying texture evolution during hot rolling of AZ31 Twin Roll Cast strip

    Science.gov (United States)

    Gorelova, S.; Schaeben, H.

    2015-04-01

    Multi-pass rolling experiments with an AZ31 Twin Roll Cast (TRC) alloy were performed on an industrial scaled four-high rolling mill. Within the rolling with an intermediate annealing the evolution of texture was investigated. To quantify the extent of preferred crystallographic orientation experimental X-ray pole figures were measured after different process steps and analyzed using the free and open Matlab® toolbox MTEX for texture analysis. The development of the fiber texture was observed and analyzed in dependence on rolling conditions. In the initial state the specimen exhibits a texture composed of a weak basal texture and a cast texture with {0001}-planes oriented across the rolling direction. During the following rolling process a fiber texture was developed. The expected strength increment of the fiber texture was quantitatively confirmed in terms of volume portions of the orientation density function around the fiber and in terms of the canonical parameters of fitted pseudo Bingham distributions. On the results of this work a model for prediction of the texture evolution during the strip rolling of magnesium in the examined parameter range was developed.

  5. NORMAL PRESSURE AND FRICTION STRESS MEASUREMENT IN ROLLING PROCESSES

    DEFF Research Database (Denmark)

    Henningsen, Poul; Arentoft, Mogens

    2005-01-01

    A load transducer has been developed to measure the contact forces in the deformation zone during rolling. The transducer consists of a strain gauge equipped insert, embedded in the surface of the roll. The length of the insert exceeds the contact length between material and roll. By analyzing the output from the transducer, the friction stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by a lower disturbance of lubricant film and material flow and limited penetration of material between transducer and roll. Aluminum, cupper and steel strips with a width of 40 mm was rolled with reduction varying from 2.7% to 29%, in a pilot mill. For evaluating the transducer, the measured contact forces are compared with external measurements of roll separating forces and torque. The determined friction coefficients are compared with values found by forward slip measurements.

  6. Production of talc nano sheets via fine grinding and sonication processes

    International Nuclear Information System (INIS)

    Fine grinding of high purity talc in jet mill at low grinding pressure was carried out by varying the feed rate and classifier rotational speed. These ground particles were sonicated in laboratory ultrasonic bath by varying the soniction period at five levels. The ground and sonicated particles were characterized in terms of particle size and particle size distribution. Mechanochemical and sonochemical effect of talc was determine via X-ray diffraction. Particle shape and surface texture of the ground and sonicated product was determined via scanning electron microscope and transmission electron microscope. The ground particle size exhibited particle size below 10 ?m with narrow size distribution. The reduction of peak intensity in (002) plane indicated the layered structure has been distorted. The sonicated talc shows that the thickness of the talc particles after the sonication process is 20 nm but the lateral particle size still remains in micron range. The reduction of the XRD peak intensity for (002) plane and thickness of sonicated talc as shown in SEM and TEM micrographs proves that fine grinding and sonication process produces talc nano sheets. (author)

  7. Rolling Process Modeling Report. Finite-Element Model Validation and Parametric Study on various Rolling Process parameters

    Energy Technology Data Exchange (ETDEWEB)

    Soulami, Ayoub [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-06-15

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum alloy plate-type fuel for high-performance research reactors in the United States. This work supports the U.S. Department of Energy National Nuclear Security Administration’s Office of Material Management and Minimization Reactor Conversion Program. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll-separating forces for various rolling mill geometries for PNNL, Babcock & Wilcox Co., Y-12 National Security Complex, Los Alamos National Laboratory, and Idaho National Laboratory. The model developed and presented in a previous report has been subjected to further validation study using new sets of experimental data generated from a rolling mill at PNNL. Simulation results of both hot rolling and cold rolling of uranium-10% molybdenum coupons have been compared with experimental results. The model was used to predict roll-separating forces at different temperatures and reductions for five rolling mills within the National Nuclear Security Administration Fuel Fabrication Capability project. This report also presents initial results of a finite-element model microstructure-based approach to study the surface roughness at the interface between zirconium and uranium-10% molybdenum.

  8. Rolling Process Modeling Report. Finite-Element Model Validation and Parametric Study on various Rolling Process parameters

    International Nuclear Information System (INIS)

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum alloy plate-type fuel for high-performance research reactors in the United States. This work supports the U.S. Department of Energy National Nuclear Security Administration's Office of Material Management and Minimization Reactor Conversion Program. This report documents modeling results of PNNL's efforts to perform finite-element simulations to predict roll-separating forces for various rolling mill geometries for PNNL, Babcock & Wilcox Co., Y-12 National Security Complex, Los Alamos National Laboratory, and Idaho National Laboratory. The model developed and presented in a previous report has been subjected to further validation study using new sets of experimental data generated from a rolling mill at PNNL. Simulation results of both hot rolling and cold rolling of uranium-10% molybdenum coupons have been compared with experimental results. The model was used to predict roll-separating forces at different temperatures and reductions for five rolling mills within the National Nuclear Security Administration Fuel Fabrication Capability project. This report also presents initial results of a finite-element model microstructure-based approach to study the surface roughness at the interface between zirconium and uranium-10% molybdenum.

  9. Vibration syndrome and vibration in pedestal grinding.

    OpenAIRE

    Starck, J; Färkkilä, M; Aatola, S; Pyykkö, I; Korhonen, O

    1983-01-01

    At one Finnish foundry all the workers had typical symptoms of vibration induced white finger (VWF) after they began using a new type of pedestal grinding machine. The objectives of this study were to establish the severity of the symptoms and the difference in vibration exposure between the new and the old machines. Vibration detection thresholds and grip forces were measured, as well as the vibration in the casting and in the wrist simultaneously. The mean latency for VWF among the grinders...

  10. A reliability analysis for the grinding process

    OpenAIRE

    Tolvanen, Pekka

    2011-01-01

    This Bachelor’s thesis was made in collaboration with the Service Product Center Espoo of Outotec (Finland) Oy during the spring semester 2011. The main objectives of this thesis were to create a reliability analysis of the mineral enrichment process grinding circuit and to examine the possibilities for the analysis as a company’s new service product. The scope for this thesis was limited by the mandator. As the machinery of the process industry is getting older, the role of maintenance ...

  11. A new transducer for roll gap measurements of the roll pressure distribution and the friction condition in cold flat rolling

    DEFF Research Database (Denmark)

    Lagergren, Jonas; Wanheim, Tarras

    2005-01-01

    Background/purpose The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, this to overcome problems in previous measurements in the past 70 years. Method The new idea is to increase the contact surface of the transducer, to be larger than the arc of contact. This is in the opposite way, compared to the smaller and smaller contact pin design that has been prevailing. Results The measurements where conducted during cold dry rolling of both copper strips and stainless steel strips in a pilot mill. The recordings were selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed. Conclusions The new transducer works very well, it was seen to be robust and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected by the authors and a good reproducibility, together with a proven agreement between recorded signals and signals simulated. Keywords Friction stress, normal pressure distribution, roll bite measurements, cold flat rolling of metals

  12. Underground milling of uranium ores

    International Nuclear Information System (INIS)

    Full text: This paper presents and analyzes the new concept of underground milling of high-grade uranium ore. Compared to conventional milling on surface, the underground milling scheme appears to offer significant cost savings and a lower environmental impact. The paper describes the underground milling scheme, presents process flowsheets and plant layouts, and provides an assessment of potential benefits from underground milling. In response to the current supply/demand situation for uranium, there has been, for the past few years, a 'uranium rush' in many parts of the world, including the resource-rich Athabasca basin situated in northern Saskatchewan. In a recent count, there were over forty uranium companies looking for uranium in this region. Positive results from any of these exploration activities could, depending on their location, potentially provide a source of additional feedstock for any of the existing milling centres in northern Saskatchewan and/or result in the establishment of additional new milling capacity. Underground milling would be considered in the latter instance. The above flowsheet shows the basics of the proposed underground milling scheme, which assumes the existence of a high-grade underground uranium mine, similar to the current McArthur River mine or the planned Cigar Lake mine. Grinding, leaching, solid/liquid separation and tailings deposition are all carried out underground. Leach liquor is pumped to surface for impurity removal, precipitation and drying. The impurities, removed as chemical precipitates, are moved back underground for disposal. Expected environmental benefits are significant and include reduction of surface visual impact, leach residues remain underground, and no tailings management facility on surface. Indeed the process residue is arguably more isolated from the environment than was the ore before mining. Contaminant transport from the stored tailings to surface waters is extremely slow. Application of membrane technology to water treatment for the underground milling scheme is expected to provide an aqueous effluent with minimal loading to the environment. In addition to these substantial environmental benefits, underground milling is expected to give a capital cost saving on the order of 35% and an operating cost saving on the order of 30% relative to conventional mining and milling. (author)

  13. Development of dissimilar metal transition joint by hot bond rolling

    International Nuclear Information System (INIS)

    Metallurgically bonded transition joints which enable to connect reprocessing equipments made of superior corrosion resistant valve metals (Ti-5Ta, Zr or Ti) to stainless steel piping are required for nuclear fuel reprocessing plants. The authors have developed dissimilar transition joints made of stainless steel and Ti-5Ta, Zr or Ti with an insert metal of Ta by the hot bond rolling process of clad bars and clad pipes, using a newly developed mill called 'rotary reduction mill'. This report presents the manufacturing process of dissimilar transition joints produced from the clad pipe with three layers by the hot bond rolling. First, the method of hot bond rolling of clad pipe is proposed. Then, the mechanical and corrosion properties of the dissimilar transition joints are evaluated in detail by carrying out various tests. Finally, the rolling properties in the clad pipe method are discussed. (author)

  14. Multi-stage FE simulation of hot ring rolling

    Science.gov (United States)

    Wang, C.; Geijselaers, H. J. M.; van den Boogaard, A. H.

    2013-05-01

    As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, referred to as preform, is then rolled by the ring rolling mill. For an accurate simulation of hot ring rolling, it is crucial to include the deformations, stresses and strains from the upsetting and piercing process as initial conditions for the rolling stage. In this work, multi-stage FE simulations of hot ring rolling process were performed by mapping the local deformation state of the workpiece from one step to the next one. The simulations of upsetting and piercing stages were carried out by 2D axisymmetric models using adaptive remeshing and element erosion. The workpiece for the ring rolling stage was subsequently obtained after performing a 2D to 3D mapping. The commercial FE package LS-DYNA was used for the study and user defined subroutines were implemented to complete the control algorithm. The simulation results were analyzed and also compared with those from the single-stage FE model of hot ring rolling.

  15. Generation of wear during the production of drug nanosuspensions by wet media milling.

    Science.gov (United States)

    Juhnke, Michael; Märtin, Dirk; John, Edgar

    2012-05-01

    Wet media milling is an established technique for the commercialized top-down production of nanoparticulate drug suspensions. These drug nanosuspensions can be transferred into the related drug products, like capsules, tablets and injectables. The generation of wear during stirred media milling of a drug compound was investigated for grinding media made from yttrium stabilized zirconia. Drug compound and drug nanosuspension were characterized initially by their mechanical and rheological properties. The generation of wear from grinding media has been investigated simultaneously with the reduction of drug particle size by evaluating several grinding media supplier and diameter as well as process parameters stirrer tip speed and specific energy input. Grinding media quality and process parameters were identified with strong impact on the amount of generated wear and on drug particle size distribution. Wear from grinding media characterized by elemental zirconium and yttrium could be significantly minimized by operating with the favored grinding media quality and with optimal stirrer tip speed and specific energy input. Wear debris, respectively wear particles from grinding media, were identified with respect to morphology and particle size. Finally, the overall contamination by raw materials and by wear during processing characterized by elemental iron, silicium, yttrium and zirconium as well as the mean size of contamination particles are presented for selected drug nanosuspensions. PMID:22269938

  16. Microstructure Characterization of Mechanically Activated Talc in Jet Mill Using XRD Line Broadening Technique

    Science.gov (United States)

    Palaniandy, S.; Azizli, K. A. M.

    2010-03-01

    Fine grinding process of talc was carried out in jet mill by varying the operational parameter such as feed rate, classifier frequency and grinding pressure. The size reduction and mechanochemical effect of talc take place simultaneously as jet mill is an energy intensive grinding mill. The minimum particle size obtained was 4.28 ?m with span value of 1.30. The crystallinity values of ground product ranging from 71% to 91%. The crystallite size of the ground silica is ranging from 147.69 nm to 353.72 nm whilst the lattice strain was ranging from 0.08 to 0.20. After sonication process in ulrea sonic bath, the ground talc were in nano sheet where its thickness was around 20 nm.

  17. Improvement of hydrogen-storage properties of Mg by reactive mechanical grinding with Fe2O3

    International Nuclear Information System (INIS)

    We tried to improve the H2-sorption properties of Mg by mechanical grinding under H2 (reactive mechanical grinding) with Fe2O3 under various milling conditions. The sample Mg-10 wt.%Fe2O3 prepared by milling at a revolution speed of 250 rpm for 24 h has the best hydrogen-storage properties. It absorbs 5.05 wt.% hydrogen at 593 K under 12 bar H2 for 60 min at the first cycle. Its activation is accomplished after three hydriding-dehydriding cycles. The activated sample absorbs 4.22 wt.% hydrogen at 593 K, 12 bar H2 for 10 min. The reactive grinding of Mg with Fe2O3 increases the H2-sorption rates by facilitating nucleation (by creating defects on the surface of the Mg particles and by the additive), by making cracks on the surface of Mg particles and reducing the particle size of Mg and thus by shortening the diffusion distances of hydrogen atoms. Hydriding-dehydriding cycling also increases the H2-sorption rates by creating defects on the surface of the Mg particles, and by making cracks on the surface of Mg particles and reducing the particle size of Mg

  18. GEOMETRICAL CHARACTERIZATION OF MICRO END MILLING TOOLS

    DEFF Research Database (Denmark)

    Borsetto, Francesca; Bariani, Paolo

    2004-01-01

    The milling process is one of the most common metal removal operation used in industry. This machining process is well known since the beginning of last century and has experienced, along the years, many improvements of the basic technology, as concerns tools, machine tools, coolants/lubricants, milling strategies and controls. Moreover the accuracy of tool geometry directly affects the performance of the milling process influencing the dimensional tolerances of the machined part, the surface topography, the chip formation, the cutting forces and the tool-life. The dimensions of certain geometrical details, as for instance the cutting edge radius, are determined by characteristics of the manufacturing process, tool material, coating etc. While for conventional size end mills the basic tool manufacturing process is well established, the reduction of the size of the tools required for the manufacturing of miniature parts by micro milling puts further challenges on to the manufacturing process. The whole geometry of the tools cannot be directly downscaled with the tool diameter. Besides the physical limit in the reduction of the cutting edge radius constituted by the grain size of sintered carbides the error motion during the grinding wheels do not allow using identical paths for tools having differences in diameter of more than one order of magnitude. Thus grinding paths for micro and mills are simplified in comparison to those for larger tools of similar shape. [1] The aim of the present report is to develop procedures for the geometrical characterization of micro end milling tools in order to define a method suitable for the quality assurance in the micro cutting field.

  19. Measurement of the wear rate of cast grinding balls using radioactive tracers

    International Nuclear Information System (INIS)

    The wear rate of grinding balls used in ball mills is usually hard to determine under operational conditions and little is known-about the factors determining ball life. Radioactive tracers have been used successfully to mark cast steel balls to obtain information on their life under various operating conditions for comparison with balls of different type or composition. A batch of marked steel balls has been followed through a milling operation over several weeks and statistics on wear and loss of weight have been obtained. In the test runs cobalt-60 was added to the molten metal before casting and the balls were then observed in use at an iron mine. The radioactive batch was added to a ball mill with a normal charge of about 75 tons and the mill charge was sampled at weekly intervals to pick out active balls. These balls were inspected and weighed, and the wear rate has been calculated. This procedure has proved to be a practical way of investigating wear properties under plant operating conditions. (author)

  20. Microstructure and texture of asymmetrically rolled aluminium and titanium after deformation and recrystallization

    Science.gov (United States)

    Wronski, M.; Wierzbanowski, K.; Wronski, S.; Bacroix, B.

    2015-08-01

    Asymmetric rolling is used to modify material properties and to reduce forces and torques applied during deformation. This geometry of deformation is relatively easy to implement on existing industrial rolling mills and it can provide large volumes of a material. The results of the study of microstructure and crystallographic texture in asymmetrically rolled aluminium 6061 and titanium (grade 2) are presented in this work. These characteristics were determined using the EBSD technique and X-ray diffraction. The rolling asymmetry was realized using two identical rolls, driven by independent motors, rotating with different angular velocities. It was found that asymmetric rolling leads to microstructural refinement and texture rotation (around the transverse direction). The impact of asymmetric rolling on microstructural refinement appears also in recrystallized samples of both materials. On the other hand, texture rotation, caused by asymmetric rolling, persists after annealing in titanium but not in aluminium samples.

  1. 7 CFR 58.726 - Cutting and grinding.

    Science.gov (United States)

    2010-01-01

    ...Agriculture 3 2010-01-01 2010-01-01 false Cutting and grinding. 58.726 Section 58.726 Agriculture...Service 1 Operations and Operating Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be...

  2. 30 CFR 56.14115 - Stationary grinding machines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 56.14115 Section 56.14115 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines....

  3. Effects of grinding on certain crystalline structures; Influence de broyage sur quelques structures cristallines

    Energy Technology Data Exchange (ETDEWEB)

    Tekiz, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-06-15

    The effects of grinding on certain crystalline substances (ZnO, ZnS, Sb), have been studied using X-ray diffraction and electron microscopy. The treatments were carried out using a vibrating mill which involves a higher energy than more conventional equipment such as ball-mills. Various methods have been proposed for determining the width of the intrinsic profile ({beta}). In the case of zinc oxide it has been shown possible to differentiate the respective contributions of the fragmentation effects and of lattice deformation effects to the overall effects of the grinding. For the two types of zinc sulfide (blend and Wurtzite) it has been shown that the blend-wurtzite) transition point is very much decreased, and that the rate of transformation of wurtzite into the stable form (blend) at room temperature is considerably increased by the grinding. In the case of antimony, the method of fragmentation shows the existence of an anisotropy which appears to be connected with easily cleavable planes. These observations show that in the case of grinding carried out with sufficient energy, the accumulation of this energy in the matter through the creation of lattice defects can accelerate the reaction rate or bring about physical transformations. (author) [French] Les effets du broyage sur certains corps cristallises (ZnO, ZnS, Sb) ont ete etudies a l'aide de la diffraction de rayons X et de la microscopie electronique. Les broyages ont ete effectues au moyen d'un vibro-broyeur qui met en jeu une energie superieure par rapport aux appareils plus conventionnels tels que les broyeurs a boulets. Diverses methodes concernant la determination de la largeur du profil intrinseque ({beta}) ont ete proposees. Dans le cas de l'oxyde de zinc on a montre la possibilite de differencier les contributions de l'effet de fragmentation et celui de perturbation du reseau, a l'effet total du broyage. Avec les deux varietes de sulfure de zinc (blende et Wurtzite) on a montre que le point de transformation de la blende en Wurtzite) etait fortement abaisse et que la transformation de la Wurtzite vers la forme stable (blende) a la temperature ambiante etait considerablement acceleree par le broyage. Dans le cas de l'antimoine le mode de fragmentation fait apparaitre une anisotropie qui doit etre reliee a l'existence des plans de clivage facile. Ces observations montrent que dans le cas d'un broyage effectue avec une energie suffisante, l'accumulation de cette energie dans la matiere par creation de defauts de reseau peut accelerer la vitesse de reaction ou provoquer des transformations physiques. (auteur)

  4. 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 ?rst 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 ?nish 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.

  5. Investigation of Grinding Effects in Binary Mixtures from the TiO 2-SnO 2-V 2O 5System

    Science.gov (United States)

    Begin-Colin, S.; Le Caër, G.; Mocellin, A.; Jurenka, C.; Zandona, M.

    1996-11-01

    Solid solution formation induced by dry ball-milling under an argon atmosphere has been investigated in binary mixtures from the TiO 2-SnO 2-V 2O 5system mainly by X-ray diffraction and differential scanning calorimetry. Grinding experiments followed by heat treatments result in substantial solid solubili_ties in all three binaries. Under our experimental conditions, the solubility after grinding depends solely on the nature of grinding media particularly in V 2O 5based systems, when reduction reactions take place between grinding tools and oxide particles. The results demonstrate that the interaction between TiO 2or SnO 2and V 2O 5follows from the fact that SnO 2and TiO 2are first slightly reduced during milling and subsequently reoxidized by V 2O 5. These interactions promote solid solution formation and the development of a reduced disordered vanadium oxide layer at the surface of SnO 2grains. The final state of powders, where the interface density between both oxides is very high, could be of interest in catalysis.

  6. Effect of grinding intensity and pelleting of the diet on indoor particulate matter concentrations and growth performance of weanling pigs.

    Science.gov (United States)

    Ulens, T; Demeyer, P; Ampe, B; Van Langenhove, H; Millet, S

    2015-02-01

    This study evaluated the effect of feed form and grinding intensity of the pig diet and the interaction between both on the particulate matter (PM) concentrations inside a pig nursery and the growth performances of weanling pigs. Four diets were compared: finely ground meal, coarsely ground meal, finely ground pellets, and coarsely ground pellets. Four weaning rounds with 144 pigs per weaning round, divided over 4 identical compartments, were monitored. Within each weaning round, each compartment was randomly assigned to 1 of 4 treatments. A hammer mill with a screen of 1.5 or 6 mm was used to grind the ingredients of the finely ground and coarsely ground feeds, respectively. Indoor concentrations of the following PM fractions were measured: PM that passes through a size-selective inlet with a 50 % efficiency cutoff at 10 (PM10) , 2.5 (PM2.5), or 1 (PM1) ?m aerodynamic diameter, respectively (USEPA, 2004). Feeding pelleted diets instead of meal diets gave rise to higher PM10 (P feed form and grinding intensity was found for any of the PM fractions. Interactions (P feed form and grinding intensity on ADFI and ADG were found. Grinding intensity had an effect only on the meal diets with higher ADFI for the coarsely ground meal. Pigs fed the finely ground meal had a lower (P Feed efficiency was influenced only by the feed form (P feed gave rise to a higher G:F. In conclusion, a contradiction between environmental concerns and performance results was found. Feeding pelleted diets to the piglets improved growth performance but also increased indoor PM concentrations. PMID:25548204

  7. High-speed milling of light metals

    Directory of Open Access Journals (Sweden)

    F. Cus

    2007-09-01

    Full Text Available Purpose: of this paper: Introduction applicability of high-speed cutting of light metals is presented in this paper.Design/methodology/approach: HSC is the result of numerous technical advances ensuring that milling has become faster than conventional milling and has gained importance as a cutting process. The advantages of the HSC milling are higher productivity owing to the reduction of machining times increase of the flow time of production, reduction of the number of technological operations, increase of the surface quality and longer service life of tools. The machining conditions for execution of the HSC (36000min-1 and feeding 20m/min require modernly built machine tools to meet those machining conditions.Findings: Continuous development of new materials is more and more dynamical, particularly, in the automobile, aircraft and electronic industry and in the manufacture of various mechanical parts. Also the achievements in the area of building of machines and tools, ensuring high cutting speeds (highly efficient machining have contributed to development of the process.Research limitations/implications: High quality of the surfaces, the quality of this so-called HSC milling can be compared to grinding.Practical implications: High-speed milling of light metals from aluminium and magnesium is more and more frequently used in practice. This result is high quality of the surface and shorter machining times. In some cases when machining by grinding is specified, the latter is omitted.Originality/value: The applicability of high-speed milling has proved to be successful, when aluminum and magnesium alloying materials are machined.

  8. Model Predictive Control for an Industrial SAG Mill

    DEFF Research Database (Denmark)

    Ohan, Valeriu; Steinke, Florian

    2012-01-01

    We discuss Model Predictive Control (MPC) based on ARX models and a simple lower order disturbance model. The advantage of this MPC formulation is that it has few tuning parameters and is based on an ARX prediction model that can readily be identied using standard technologies from system identication. When applied to MIMO systems we call this controller a MIMO-ARX based MPC. We use an industrial Semi-Autogenous Grinding (SAG) mill to illustrate the performance of this controller. SAG mills are the primary units in a grinding chain and also the most power consuming units. Therefore, improved control of SAG mills has the potential to signicantly improve eciency and reduce the specic energy consumption for mineral processes. Grinding circuits involving SAG mills are multivariate processes. Commissioning of a control system based on a classical single-loop controllers with logic is time consuming, while MPC has the potential to both improve the control performance and the commissioning time and expertise required. The simulation results demonstrate that the MPC based on a MIMO-ARX model is able to provide nice control performance measured by its ability to track an output reference and reject unknown disturbances. Furthermore, the method used to design the controller represents a systematic method that can be automatized for wide-spread deployment in industrial environments.

  9. Cocrystal Formation through Mechanochemistry: from Neat and Liquid-Assisted Grinding to Polymer-Assisted Grinding.

    Science.gov (United States)

    Hasa, Dritan; Rauber, Gabriela Schneider; Voinovich, Dario; Jones, William

    2015-06-15

    Mechanochemistry is an effective method for the preparation of multicomponent crystal systems. In the present work, we propose an alternative to the established liquid-assisted grinding (LAG) approach. Polymer-assisted grinding (POLAG) is demonstrated to provide a new class of catalysts for improving reaction rate and increasing product diversity during mechanochemical cocrystallization reactions. We demonstrate that POLAG provides advantages comparable to the conventional liquid-assisted process, whilst eliminating the risk of unwanted solvate formation as well as enabling control of resulting particle size. It represents a new approach for the development of functional materials through mechanochemistry, and possibly opens new routes toward the understanding of the mechanisms and pathways of mechanochemical cocrystal formation. PMID:25939405

  10. Grinding Characteristics of Reaction Bonded Silicon Carbide

    Directory of Open Access Journals (Sweden)

    YAO Wang, ZHANG Yu-Min, HAN Jie-Cai, ZHOU Yu-Feng

    2012-07-01

    Full Text Available Surface topography, surface residual stress and bending strength of RBSiC ground using diamond wheel were studied. Grinding RBSiC is removed mainly by brittle fracture and lightly by ductile cutting. With the increase of down feed, surface roughness Ra increases. Burnishing with no down feed can improve the Ra in some way. With increasing down feed, the compressive residual stress decreases because of an inadequately cooling effect. Compare with the specimens grounded using 0.9 ?m/s, those using down feed of 1.35 ?m/s have worse surface quality. Considering both the processing efficiency and the surface quality, the optimum parameters are as follow: 0.9?m/s down feed, 2.1 r/min work table rotational speed and 1 min burnishing.

  11. The Grinding Wheel Performance in the Transverse Cylindrical Grinding of an Eutetic Alloy

    Directory of Open Access Journals (Sweden)

    Bianchi Eduardo Carlos

    2002-01-01

    Full Text Available This paper presents a research in which the performance of two different grinding wheels (a conventional and a CBN wheel was evaluated in a transverse cylindrical grinding of a eutectic alloy. Three cutting conditions were tested: rough, semi-finishing and finishing. As evaluating parameters, the cutting force, the roughness and the wheel wear were measured. As a result, the best values of the cutting force and the roughness were obtained when grinding with the conventional wheel, due to the best dressing operation performed, for all the cutting conditions. The CBN presented the best G ratio values. Although, the G ratio values observed for the CBN wheel were lower than the expected one due to the non-effective dressing operation applied. In the conditions tested, in terms of cutting force and roughness, the conventional wheel is the best choice. In terms of G ratio, a cost analysis is crucial to determine if the differences observed among the wheels can justify the use of the CBN wheel. In a positive case, the dressing operation must be improved.

  12. The Grinding Wheel Performance in the Transverse Cylindrical Grinding of an Eutetic Alloy

    Scientific Electronic Library Online (English)

    Eduardo Carlos, Bianchi; Eraldo Jannone da, Silva; Vinicio Lucas, Vargas; Thiago Cardoso, Magagnin; Rodrigo Daun, Monici; Osmar, Vicari Filho; Paulo Roberto de, Aguiar.

    2002-10-01

    Full Text Available This paper presents a research in which the performance of two different grinding wheels (a conventional and a CBN wheel) was evaluated in a transverse cylindrical grinding of a eutectic alloy. Three cutting conditions were tested: rough, semi-finishing and finishing. As evaluating parameters, the c [...] utting force, the roughness and the wheel wear were measured. As a result, the best values of the cutting force and the roughness were obtained when grinding with the conventional wheel, due to the best dressing operation performed, for all the cutting conditions. The CBN presented the best G ratio values. Although, the G ratio values observed for the CBN wheel were lower than the expected one due to the non-effective dressing operation applied. In the conditions tested, in terms of cutting force and roughness, the conventional wheel is the best choice. In terms of G ratio, a cost analysis is crucial to determine if the differences observed among the wheels can justify the use of the CBN wheel. In a positive case, the dressing operation must be improved.

  13. Development of a modified grind-leach process for processing Triso-coated reactor fuel

    International Nuclear Information System (INIS)

    An advanced or modified grind-leach process has been under development as a head-end treatment to separate the fuel components from spent tri-structural-isotropic (TRISO)-coated fuel and to prepare the fuel for separations in a standard aqueous processing plant. Conceptually, the process involves removing the fuel compacts from the graphite fuel element, grinding the compacts to expose the fuel kernel, optionally separating the lighter carbon particles from the heaver fuel particles and leaching or dissolving the fuel components from the remaining carbon and silicon carbide fines. The nitric acid leaching step may be directly interfaced with conventional aqueous solvent extraction processes. The finely divided carbon waste may be reformed into a compact and durable waste form. Laboratory studies of the key process steps have been performed using surrogates because irradiated fuels were not available. The fuel compacts may be removed from the graphite block to eliminate nearly all the block-graphite and thus the primary source of organic by-products in the leaching step. Tests have been recently completed to study the milling process. Using commercially available laboratory-scale jet mills, tests with surrogate fuel particles, including TRISO-coated zirconia and hafnia, showed that the friable coatings could be stripped from the relatively tough kernels. The coating fragments were very small, whereas the kernel fragments were larger. Similar results were obtained with unirradiated coated urania kernels. Because the coating layers were milled to very small particle sizes, it was anticipated that acids would have good access to the fuel components. This mitigates losses of fuel materials embedded in the coatings. With the coatings breached or removed, the kernels would tend to dissolve completely. These tests strongly indicate that jet milling produces a product conducive to acid leaching. Proof-of-principle tests using simulated crushed TRISO-coated fuel have indicated little, if any, production of soluble organic species in the leaching process. Nitric acid leaching of milled surrogate TRISO-coated fuel followed by filtering produced a clear yellow solution. This solution was used in shake-out tests with uranium extraction solvent (tri-n-butyl phosphate in n-dodecane diluent). No physical process problems such as foaming, formation of emulsions, or failure to achieve clean phase separation were observed. Negligible effects on the solvent extraction process were evidenced by measured distribution ratios close to expected values. These initial studies indicate that the modified crush-leach process is suitable for processing of TRISO-coated fuels. Further studies using irradiated fuels are recommended. Processes to fabricate a carbon waste form should also be tested. (authors)

  14. Ship Roll Damping Control

    DEFF Research Database (Denmark)

    Perez, Tristan; Blanke, Mogens

    2012-01-01

    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of difficulties associated with control system designs, which have proven to be far from trivial due to fundamental performance limitations and large variations of the spectral characteristics of wave-induced roll motion. This tutorial paper presents an account of the development of various ship roll motion control systems tog...

  15. Influence of planetary milling parameters on the properties of the activated silicon and aluminium nitride powders

    International Nuclear Information System (INIS)

    Mechanochemical processing of the silicon nitride based powders by high energy milling in a planetary mill is reported. The particle size distribution, specific surface area and their morphology after milling were studied after a period of a short (30 min) or long (up to 360 min) grinding. It has been shown that mechanochemical processing with the high energy led to the considerable destruction of the component crystal lattice apart from particles diminution, and moreover, to decomposition of the applied surfactant. As a result, significant agglomeration of powder particles occurred after the given milling time.

  16. Influence of planetary milling parameters on the properties of the activated silicon and aluminium nitride powders

    Science.gov (United States)

    Pawlik, T.; Sopicka-Lizer, M.; W?odek, T.; Miku?kiewicz, M.

    2011-05-01

    Mechanochemical processing of the silicon nitride based powders by high energy milling in a planetary mill is reported. The particle size distribution, specific surface area and their morphology after milling were studied after a period of a short (30 min) or long (up to 360 min) grinding. It has been shown that mechanochemical processing with the high energy led to the considerable destruction of the component crystal lattice apart from particles diminution, and moreover, to decomposition of the applied surfactant. As a result, significant agglomeration of powder particles occurred after the given milling time.

  17. Rolling Shutter Motion Deblurring

    KAUST Repository

    Su, Shuochen

    2015-06-07

    Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algo- rithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

  18. Methodology for automatic selection of passes in surface grinding

    Scientific Electronic Library Online (English)

    Fábio R. L., Dotto; Paulo Roberto de, Aguiar; Rogério, Thomazella; Eduardo Carlos, Bianchi.

    2007-03-01

    Full Text Available The main purpose of this work is the development of computational tools in order to assist the on-line automatic detection of burn in the surface grinding process. Most of the parameters currently employed in the burning recognition (DPO, FKS, DPKS, DIFP, among others) do not incorporate routines fo [...] r automatic selection of the grinding passes, therefore, requiring the user’s interference for the choice of the active region. Several methods were employed in the passes extraction; however, those with the best results are presented in this article. Tests carried out in a surface-grinding machine have shown the success of the algorithms developed for pass extraction.

  19. Cryogenic grinding technology for traditional Chinese herbal medicine

    Science.gov (United States)

    Li, Shimo; Ge, Shuangyan; Huang, Zhongping; Wang, Qun; Zhao, Haoping; Pan, Huaiyu

    The fundamental principle of cryogenic grinding (cryogrinding) for Chinese herbal medicine is similar to that of grinding methods for conventional materials, but the compositions are very complex, containing aromatics of high volatility, oils and fats, which are easily oxidized. Using liquid nitrogen or liquid air as the cryogen, all of these thermosensitive Chinese herbal medicines can be ground below their brittle temperature. The colour and other properties of the products of cryo-grinding will not be changed and the flavour and nutrition of the medicines will not be lost.

  20. Numerical analysis of small recessed silicon carbide grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2010-11-01

    Full Text Available Purpose: Silicon carbide grinding wheels are tools used in manufacturing industry to form precision componentsand continue to be used to increase production rates due to their ability to remove high volumes of material athigh speeds. There is a demand to increase the speed of rotation of the grinding wheel in order to achieve highremoval rates. The increase in speed creates a situation where the grinding machine and the operator are subjectedto a possible catastrophic failure of the wheel due to the stresses generated in the coarse brittle structure of thevitrified grinding wheel. The study focused on building and analyzing computer models of grinding wheels withrecessed features spinning at different rotational speeds. By employing a computational approach, it was possibleto determine the maximum principal stresses in the wheel together with the location of the stresses. The geometryof vitrified wheels considered included a plain-sided rotating wheel and a recessed rotating wheel.Design/methodology/approach: The paper shows how stresses and factors of safety are calculated in order topredict the bursting speeds of small recessed SiC grinding wheels. The main methods used include finite elementanalysis and mechanical testing of abrasive materials. The approach of the paper is to integrate the use of numericalanalysis techniques and experimental techniques to predict the safe operating conditions of SiC abrasive products.Findings: Calculations were conducted to determine maximum stress in parallel-sided and recessed cup wheels.Relevant factors of safety and bursting speed were also calculated and compared with experimental data. Thepaper proves the usefulness and applicability of a method developed for taking account of stress concentrationsat the recess of small cup-shaped silicon carbide grinding wheels.Research limitations/implications: The paper is limited to analyzing small recessed SiC grinding wheels.Further work should focus on large recessed wheels and wheels made with different abrasive grains and bondingmaterials. The type of porosity distribution should also be investigated.Practical implications: The paper shows how numerical methods are used to design safe operating conditionsfor brittle grinding wheels. The methods used show that numerical techniques are suitable for calculating themeasures of safety that are an important consideration when designing high speed rotating grinding wheels thatcan be devastating if allowed to fail in service.Originality/value: The originality in the paper is revealed owing to the fact that fracture mechanics principlesare applied to the prediction of failure of rotating grinding wheels. The paper is of practical importance tomechanical designers who are responsible for the safe design of grinding wheels.

  1. Production of scallop shell nanoparticles by mechanical grinding as a formaldehyde adsorbent

    International Nuclear Information System (INIS)

    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.

  2. Pole-placement optimizing controller and application to a simulated autogeneous grinding circuit

    International Nuclear Information System (INIS)

    An optimizing controller is developed in order to operate the process at its optimum according to an unconstrained criterion despite disturbances. The gradient of the criterion is taken as the controlled variable and a null set point is used in order to maximize the criterion. A local dynamic moving average model is identified and its gain is calculated to evaluate the gradient on-line. A low-forgetting factor in conjunction with a fixed low-pass filter is used in order to fix the dynamic response of the measured gradient. A multivariable controller using a pole cancellation method is used to achieve zero gradient set point. The method is applied to the optimization of the power drawn by a simulated autogeneous grinding mill. (author)

  3. Pole-placement optimizing controller and application to a simulated autogeneous grinding circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lestage, R.; Pomerleau, A. [Univ. Laval, Groupe de Recherche sur les Applications de l' Informatique a l' industrie Minerale, Dept. de genie electrique et de genie informatique, Sainte-Foy, PQ (Canada)

    1999-07-01

    An optimizing controller is developed in order to operate the process at its optimum according to an unconstrained criterion despite disturbances. The gradient of the criterion is taken as the controlled variable and a null set point is used in order to maximize the criterion. A local dynamic moving average model is identified and its gain is calculated to evaluate the gradient on-line. A low-forgetting factor in conjunction with a fixed low-pass filter is used in order to fix the dynamic response of the measured gradient. A multivariable controller using a pole cancellation method is used to achieve zero gradient set point. The method is applied to the optimization of the power drawn by a simulated autogeneous grinding mill. (author)

  4. 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.

  5. Annular Fuel Pellet Fabrication without Surface Grinding

    International Nuclear Information System (INIS)

    In order to increase the power density of a Pressurized Water Reactor fuel assembly, a dual cooled annular fuel has been seriously considered as a favorable option. A configurationally inherent merit of an annular fuel such as an increased heat transfer area and a thin pellet thickness results in a lot of advantages from the point of a fuel safety and its economy. Annular pellet with precisely controlled diametric tolerance is an essential element to actualize the dual cooled fuel. An hour-glassing usually occurs in a sintered cylindrical PWR fuel pellet fabricated by a conventional double-acting press due to an inhomogeneous green density distribution in a powder compact. An inhomogeneous green density distribution in a powder compact is attributed to granule-granule frictions and granule to pressing mold wall frictions. Frictions result in an irregular pressing load distribution in a powder compact. Thus, a sintered pellet undergoes a centerless grinding process in order to secure diametric tolerance specifications. In the case of an annular pellet fabrication using a conventional double-acting press, the same hour-glass shape would probably occur. The green density gradient in a powder compact depends on the pressing direction and the amount of the sintering deformation is inversely proportional to the initial green density. In case of a double-acting pressing, the middle portion of the green pellet has a lower green density than those of the top and the bottom portions of the green pellet. However, the top or the bottom portion which is far from the acting punch surface has the lowest green density in a single-acting pressing. In the present study, we are trying to find a way to minimize the diametric tolerance of the sintered annular pellet without surface grinding. Annular compacting mold with inclined inner and outer surfaces was designed by considering a difference in the diametric changes depending on the pellet height during sintering. By using a compacting mold with inclined surfaces and a single-acting press, an annular pellet can be fabricated successfully with a tolerance of less than ± 13 ?m which is the diametric tolerance specification of a conventional PWR fuel pellet

  6. Effect of grinding on thermal reactivity of ceramic clay minerals.

    Czech Academy of Sciences Publication Activity Database

    Balek, Vladimír; Perez-Magueda, L. A.; Poyato, J.; ?erný, Zbyn?k

    2007-01-01

    Ro?. 88, ?. 1 (2007), s. 87-91. ISSN 1388-6150 Institutional research plan: CEZ:AV0Z40320502 Keywords : DTA * emanation thermal analysis * grinding Subject RIV: CA - Inorganic Chemistry Impact factor: 1.483, year: 2007

  7. 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.

  8. 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...

  9. Environmental Impact of Electricity Consumption in Crushing and Grinding Processes of Traditional and Urban Gold Mining by Using Life Cycle Assessment (LCA

    Directory of Open Access Journals (Sweden)

    Nur Rafidah Yahaya

    2012-01-01

    Full Text Available Mining is not only an essential component of social and economic development since prehistoric time, but it also gives a large impact on our civilization. Gold is a noble metal that is highly valued. The extraction of minerals from earth is known as traditional mining. Gold also can be extracted from electronic waste or e-waste, and this new concept is called urban mining. There are many stages in traditional and urban mining process. However, in this study, the focus was on crushing and grinding processes to produce 1 kg of gold. Crushing and grinding are processes in the milling stage. This research evaluates and compares the environmental impacts of crushing and grinding processes, based on electricity consumption. About 50 to 65% of total electricity in milling was used for crushing and grinding processes. Life Cycle Assessment (LCA methodology was used as a tool to evaluate the environmental burdens of electricity usage in converting ore and electronic waste to gold bars. The Life Cycle Impact Assessment (LCIA of this process was interpreted by using Eco-indicator 99 assessment methods in SimaPro software. The impact categories included in this study were carcinogens, respiratory organics, respiratory inorganics, radiation, climate change, ozone layer, ecotoxicity, acidification or eutrophication, land use and minerals. The results showed that crushing and grinding from traditional mining gave the largest impact to the environment with single score of 399 Pt compared to the urban mining with only 1.81 Pt score. The highest impact in both types of mining is to human health.

  10. Adaptive Automatic Gauge Control of a Cold Strip Rolling Process

    Directory of Open Access Journals (Sweden)

    ROMAN, N.

    2010-02-01

    Full Text Available The paper tackles with thickness control structure of the cold rolled strips. This structure is based on the rolls position control of a reversible quarto rolling mill. The main feature of the system proposed in the paper consists in the compensation of the errors introduced by the deficient dynamics of the hydraulic servo-system used for the rolls positioning, by means of a dynamic compensator that approximates the inverse system of the servo-system. Because the servo-system is considered variant over time, an on-line identification of the servo-system and parameter adapting of the compensator are achieved. The results obtained by numerical simulation are presented together with the data taken from real process. These results illustrate the efficiency of the proposed solutions.

  11. Dry grinding effect on pyrophyllite-quartz natural mixture and its influence on the structural alternation of pyrophyllite.

    Science.gov (United States)

    Zhang, Jian; Yan, Jun; Sheng, Jiawei

    2015-04-01

    Infrared spectroscopy (IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray analysis (EDS) were used to investigate the evolution of mechanical destruction of the pyrophyllite structure and final ground products upon grinding with a laboratory planetary ball mill. The raw ore used in this present work was mainly composed of pyrophyllite and quartz. This pyrophyllite was more resistant toward mechanical destruction, and the crystalline order of pyrophyllite was not completely destroyed until grinding for 240 min with a 20:1 of weight ratio of the balls to powder. The existing crystalline phase in the final ground product was found to be quartz, which served as the associated phase in the original pyrophyllite mineral. The rate of destruction of pyrophyllite structure depended on the types of chemical bonds. Additionally, increasing the intensity of grinding resulted in acceleration of the mechanically induced amorphization of the pyrophyllite structure, whereas the associated quartz grains contributed to the deceleration of the amorphization of pyrophyllite. PMID:25590567

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

    OpenAIRE

    R. ?wi?cik

    2009-01-01

    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 t...

  13. Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

    Directory of Open Access Journals (Sweden)

    M. Drobne

    2014-10-01

    Full Text Available Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for roll’s shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens – SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture mechanics parameters the electro–mechanical testing machine was used.

  14. Sludge minimization achieved through grinding and reaeration

    International Nuclear Information System (INIS)

    A parallel, bench-scale study was undertaken to study the effect of grinding/blending biological solids followed by subsequent aeration for 24-hours on overall sludge production. This was compared to a completely-mixed system from which solids were wasted directly back to the aeration basin. In essence, both treatment trains employed total recycle of the waste biological solids, except that the solids from Train 2 were ground and aerated prior to re-introduction. The bench-scale reactors were continuously operated from November through December 2000 and from January through April 2001. Temperature of the wastewater during the first and second runs was maintained at 14o C and 25o C, respectively. Each parallel train was fed synthetic wastewater at a flow rate of approximately 2.25 gallons per day resulting in a hydraulic detention time of approximately 13 hours. Samples of the influent, effluent, and mixed liquor were collected weekly and the following analyses were performed: COD, pH, temperature, total solids, suspended solids, volatile suspended solids, dissolved solids, and oxygen uptake rate (OUR). Results of the study indicate that the system in which the solids were ground and re-aerated produced less sludge than the conventional system. Substrate removal rates were the same for both systems. Statistical analyses using the analysis of variance indicated the results were significant at the 95 % confidence level. (author)

  15. Model Predictive Control for an Industrial SAG Mill

    DEFF Research Database (Denmark)

    Ohan, Valeriu; Steinke, Florian; Metzger, Michael; Runkler, Thomas; Jørgensen, John Bagterp

    2012-01-01

    We discuss Model Predictive Control (MPC) based on ARX models and a simple lower order disturbance model. The advantage of this MPC formulation is that it has few tuning parameters and is based on an ARX prediction model that can readily be identied using standard technologies from system identication. When applied to MIMO systems we call this controller a MIMO-ARX based MPC. We use an industrial Semi-Autogenous Grinding (SAG) mill to illustrate the performance of this controller. SAG mills are ...

  16. Fast-roll inflation

    International Nuclear Information System (INIS)

    We show that in the simplest theories of spontaneous symmetry breaking one can have a stage of a fast-roll inflation. In this regime the standard slow-roll condition vertical bar m2 vertical bar 2 is violated. Nevertheless, this stage can be rather long if vertical bar m vertical bar is sufficiently small. Fast-roll inflation can be useful for generating proper initial conditions for the subsequent stage of slow-roll inflation in the very early universe. It may also be responsible for the present stage of accelerated expansion of the universe. We also make two observations of a more general nature. First of all, the universe after a long stage of inflation (either slow-roll or fast-roll) cannot reach anti-de Sitter regime even if the cosmological constant is negative. Secondly, the theories with the potentials with a 'stable' minimum at V(?)<0 in the cosmological background exhibit the same instability as the theories with potentials unbounded from below. This instability leads to the development of singularity with the properties practically independent of V(?). However, the development of the instability in some cases may be so slow that the theories with the potentials unbounded from below can describe the present stage of cosmic acceleration even if this acceleration occurs due to the fast-roll inflation. (author)

  17. 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, aunque debe prestarse cuidado a las posibles interacciones con aditivos reductores de agua de hormigones.

  18. Grooved roll for a high speed twin roll caster

    Directory of Open Access Journals (Sweden)

    T. Haga

    2008-04-01

    Full Text Available Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown.Design/methodology/approach: Method used in the present study was high speed twin roll caster withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby knurling and bite attached to a lathe.Findings: Findings of this research are that grooved roll was effective to eliminate the small cracks on the stripsurface. The contact condition between the roll and the melt became uniform by the small groove on the rollsurface. Contact area became small, and heat transfer between the melt and roll became small, too. As the result,chill structure did not become columnar, and crack did not occur. Groove pattern on the strip surface could beerased by the cold rolling.Research limitations/implications: Research limitation is that groove life could not be investigated.Practical implications: Practical implications are as below. The roll load was small and strip was not hot-rolledin a high speed twin roll caster. The grooved roll made strip-surface sound. Grooved 600mm width roll was tested,and usefulness of the grooved roll was shown.Originality/value: In the present study effect of the grooved roll on a high speed twin roll caster was investigated.

  19. Ship Roll Motion Control

    DEFF Research Database (Denmark)

    Perez, Tristan; Blanke, Mogens

    2010-01-01

    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of deciencies in control system designs, which have proven to be far from trivial due to fundamental performance limitations. This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performance, the...

  20. Fast-Roll Inflation

    CERN Document Server

    Linde, Andrei D

    2001-01-01

    We show that in the simplest theories of spontaneous symmetry breaking one can have a stage of a fast-roll inflation. In this regime the standard slow-roll condition |m^2| << H^2 is violated. Nevertheless, this stage can be rather long if |m| is sufficiently small. Fast-roll inflation can be useful for generating proper initial conditions for the subsequent stage of slow-roll inflation in the very early universe. It may also be responsible for the present stage of accelerated expansion of the universe. We also make two observations of a more general nature. First of all, the universe after a long stage of inflation (either slow-roll or fast-roll) cannot reach anti-de Sitter regime even if the cosmological constant is negative. Secondly, the theories with the potentials with the ``stable'' minimum at V(\\phi)<0 in the cosmological background exhibit the same instability as the theories with potentials unbounded from below. This instability leads to the development of singularity with the properties pra...

  1. Validation of the Hot Strip Mill Model

    Energy Technology Data Exchange (ETDEWEB)

    Richard Shulkosky; David Rosberg; Jerrud Chapman

    2005-03-30

    The Hot Strip Mill Model (HSMM) is an off-line, PC based software originally developed by the University of British Columbia (UBC) and the National Institute of Standards and Technology (NIST) under the AISI/DOE Advanced Process Control Program. The HSMM was developed to predict the temperatures, deformations, microstructure evolution and mechanical properties of steel strip or plate rolled in a hot mill. INTEG process group inc. undertook the current task of enhancing and validating the technology. With the support of 5 North American steel producers, INTEG process group tested and validated the model using actual operating data from the steel plants and enhanced the model to improve prediction results.

  2. Development of morphology in laser dressed grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2007-05-01

    Full Text Available Purpose: The paper describes the development of faceted morphology in laser dressed grinding wheels.Design/methodology/approach: The approach used in the paper is based on locally melting a vitrified grinding wheel and measuring features such as grain size, cooling rate and melt depth as a function of laser fluence and relating these measures to the morphology shown in the microstructures presented in the paper.Findings: The findings of this course of research lead the authors to believe that a specific morphology is dependent upon cooling rate and laser fluence.Research limitations/implications: The findings show that further research is required to fully understand how certain morphologies form as a function of cooling rate and laser fluence. It should be noted that morphologies observed in laser processed grinding wheels include cellular and fully dendritic morphologies in addition to faceted vertices.Practical implications: The results imply that laser dressed grinding wheels can be used for machining different materials at different grinding speeds. The paper also shows that much development is needed to identify laser processing conditions that are appropriate for different workpiece materials.Originality/value: The paper shows that different morphologies can be used to machine workpiece materials under different conditions. The originality in the paper is focused on the formation on minute cutting points using increasing laser fluences.

  3. In-Orbit Construction with a Helical Seam Pipe Mill

    Science.gov (United States)

    Gilhooley, N.

    The challenges of building large structures in space, and in particular a torus habitat, require novel processes. One potential method is to manufacture helical seam (also called spiral) pipe in orbit using a pipe mill. These machines turn rolls of steel or alloy into fully formed, welded and inspected pipe, pressure vessels and silos of various diameters. Pipe mills are highly automated and efficient in a factory environment and are increasingly being used for in-situ repair. By constructing in-orbit (on-orbit assembly) the launch vehicle can supply full payloads of compact, robust rolls of material; and the installation design is less restricted by fairing constraints and modular limitations. The use of a pipe mill is discussed as a possible construction method, for comparison an example design envelope is shown and further pipe mill products are considered.

  4. Determination of the relative position between grinding wheel and a cylindrical workpiece on a 7 axis grinding machine by acoustic emission

    Scientific Electronic Library Online (English)

    Walter Lindolfo, Weingaertner; Adriano, Boaron.

    2012-03-01

    Full Text Available The contact between grinding wheel and workpiece in the grinding process is recognized by acoustic emission (AE). Two acoustic emission monitoring systems (MS) were integrated into a 3 axis CNC grinding machine. A laptop allows the signal acquisition and visualization. The acquired AE RMS signals fr [...] om the contact between tool and workpiece are analyzed permitting to establish the most suitable AE monitoring system to recognize the contact in a particular grinding machine. In a second experimental setup the selected MS was installed on a 7 axis tool grinding machine at an industrial partner. At this partner, the relative position between grinding wheel and workpiece was previously determined manually. This procedure has a direct influence on the results depending on the technical skills of the operator. The automation of this activity supported by acoustic emission has led to satisfactory results regarding the relative position between grinding wheel and workpiece and contributed to the setup time reduction.

  5. Process parameter dependent growth phenomena of naproxen nanosuspension manufactured by wet media milling.

    Science.gov (United States)

    Bitterlich, A; Laabs, C; Krautstrunk, I; Dengler, M; Juhnke, M; Grandeury, A; Bunjes, H; Kwade, A

    2015-05-01

    The production of nanosuspensions has proved to be an effective method for overcoming bioavailability challenges of poorly water soluble drugs. Wet milling in stirred media mills and planetary ball mills has become an established top-down-method for producing such drug nanosuspensions. The quality of the resulting nanosuspension is determined by the stability against agglomeration on the one hand, and the process parameters of the mill on the other hand. In order to understand the occurring dependencies, a detailed screening study, not only on adequate stabilizers, but also on their optimum concentration was carried out for the active pharmaceutical ingredient (API) naproxen in a planetary ball mill. The type and concentration of the stabilizer had a pronounced influence on the minimum particle size obtained. With the best formulation the influence of the relevant process parameters on product quality was investigated to determine the grinding limit of naproxen. Besides the well known phenomenon of particle agglomeration, actual naproxen crystal growth and morphology alterations occurred during the process which has not been observed before. It was shown that, by adjusting the process parameters, those effects could be reduced or eliminated. Thus, besides real grinding and agglomeration a process parameter dependent ripening of the naproxen particles was identified to be a concurrent effect during the naproxen fine grinding process. PMID:25766272

  6. Design and fabrication of nano-scale single crystal diamond cutting tool by focused ion beam (FIB) milling

    Science.gov (United States)

    Baek, Seung-Yub

    2015-07-01

    Micro/nanoscale diamond cutting tools used in ultra-precision machining can be fabricated by precision grinding, but it is hard to fabricate a tool with a nanometric cutting edge and complex configurations. High-precision geometry accuracy and special shapes for microcutting tools with sharp edges can be achieved by FIB milling. Because the FIB milling method induces much smaller machining stress compared with conventional precision grinding methods. In this study, the FIB milling characteristics of single-crystal diamond were investigated, along with methods for decreasing the FIB-induced damage on diamond tools. Lift-off process method and Pt(Platinum) coating process method with FIB milling were investigated to reduce the damage layer on diamond substrate and quadrilateral-shaped single-crystal diamond cutting tool with cutting edge width under 500 nm were obtained.

  7. A new transducer for local load measurements of friction and roll pressure in cold flat rolling

    DEFF Research Database (Denmark)

    Lagergren, J.; Wanheim, Tarras

    2006-01-01

    The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, in order to overcome problems in previous measurements in the past 70 years. The new idea is to increase the contact surface of the transducer, to be larger than the arc of contact. This is in contrast to the smaller and smaller contact pin design that has been prevailing. The measurements were conducted during cold dry rolling of both copper strips and stainless steel strips in a pilot mill. The recordings were selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed. The new transducer works very well, it was seen to be robust and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected bythe authors and showed good reproducibility, together with a proven agreement between recorded and simulated signals.

  8. Spray Rolling Aluminum Strip

    Energy Technology Data Exchange (ETDEWEB)

    Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.

    2006-05-10

    Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

  9. In-process grinding monitoring through acoustic emission

    Scientific Electronic Library Online (English)

    Paulo R., Aguiar; Paulo J. A., Serni; Fábio R. L., Dotto; Eduardo C., Bianchi.

    2006-03-01

    Full Text Available This work aims to investigate the efficiency of digital signal processing tools of acoustic emission signals in order to detect thermal damages in grinding processes. To accomplish such a goal, an experimental work was carried out for 15 runs in a surface grinding machine operating with an aluminum [...] oxide grinding wheel and ABNT 1045 Steel as work material. The acoustic emission signals were acquired from a fixed sensor placed on the workpiece holder. A high sampling rate data acquisition system working at 2.5 MHz was used to collect the raw acoustic emission instead of the root mean square value usually employed. Many statistical analyses have shown to be effective to detect burn, such as the root mean square (RMS), correlation of the AE, constant false alarm rate (CFAR), ratio of power (ROP) and mean-value deviance (MVD). However, the CFAR, ROP, Kurtosis and correlation of the AE have been presented more sensitive than the RMS.

  10. Research on Grinding and Polishing Force Control of Compliant Flange

    Directory of Open Access Journals (Sweden)

    Li Chuang

    2015-01-01

    Full Text Available The automation of the grinding and polishing process is important to improve the production efficiency of the part surfaces. In this paper, a new compliant flange mounted on the end of the industrial robots for the robotic grinding and polishing force control is developed. With regard to the non-linear and time-varying problem of the contact force, the mathematical model of the new force control system was presented and the fuzzy PID control strategy was used to drive the proposed system. Especially, the air spring and electric proportional valve is studied to establish the model. The simulation results show that the selected control strategy has quick response and good robustness, which satisfies the real-time requirements of the grinding and polishing force control in processing.

  11. Potential release of carbon nanotubes from their composites during grinding

    International Nuclear Information System (INIS)

    We investigated the particle release caused by the grinding of polystyrene-based composites with and without single-wall carbon nanotubes (CNTs). In the results of real-time aerosol monitoring, considerable increases in the number concentration of nano-sized aerosol particles were observed during the grinding of both CNT-containing and CNT-free polystyrene. When a thermodenuder was used, the number of released nanoparticles was reduced by over 99.9%, indicating that the nanoparticles were presumably volatile particles released by the friction heat produced by grinding the composite. In an electron microscopic analysis of the aerosol particles, micron-sized particles with protruding fibers (probably CNTs) were observed, whereas free-standing CNTs were not observed.

  12. 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.

  13. Determining the onset of grinding burn using Magnetic Barkhausen Noise

    OpenAIRE

    Opoku, Kevin S

    2005-01-01

    A study of the quick non-destructive technique of Magnetic Barkhausen Noise (MBN) in detecting the onset of grinding burn in the absence of any microstructural changes during grinding has been undertaken. 51CrV4 Steel is a used in industry for manufacturing automotive parts (Nissan). Uniaxial tensile tests using a coarse surface whilst taking in situ MBN measurements were used to calibrate MBN to residual stress for hard and soft samples of 51CrV4. X-ray diffraction tests of...

  14. Study of thresholds to burning in surface grinding process

    Scientific Electronic Library Online (English)

    P. R. de, Aguiar; F. R. L., Dotto; E. C., Bianchi.

    2005-06-01

    Full Text Available This work aims at finding out the threshold to burning in surface grinding process. Acoustic emission and electric power signals are acquired from an analog-digital converter and processed through algorithms in order to generate a control signal to inform the operator or interrupt the process in the [...] case of burning occurrence. The thresholds that dictate the situation of burn and non-burn were studied as well as a comparison between the two parameters was carried out. In the experimental work one type of steel (ABNT-1045 annealed) and one type of grinding wheel referred to as TARGA model 3TG80.3 - NV were employed.

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

    Scientific Electronic Library Online (English)

    Daniel Véras, Ribeiro; Márcio Raymundo, Morelli.

    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 ce [...] ment 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.

  16. Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding

    OpenAIRE

    A. Pribulová; Baricová, D.; P. Futaš; P. Genge?

    2010-01-01

    Foundry dust can be divided into three groups: metallic dust with Fe content over 70%, mixed dust with Fe or SiO2 content between 10 –70% and sand wastes with minimum content of SiO2 about 70%. Dust from castings grinding with high Fe content (87.9%) is still landfillin Slovakia. The aim of experiments with dust from grinding has been to find the cheapest way of dust agglomeration with minimumamount of binder because of melting in the electric induction furnace. The dust was pelletized and br...

  17. Analysis of cement superplasticizers and grinding aids a literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Ervanne, H.; Hakanen, M. [Helsinki Univ. (Finland). Lab. of Radiochemistry

    2007-04-15

    This literature survey reviews the methods for analysis of cement plasticizers and organic grounding aids in cement solutions in preparation of grouts/concrete and methods for determination of plasticizers and grinding aids in groundwater conditions. The survey focuses on three different types of superplasticizers: sulphonated naphthalene condensates, sulphonated melamine condensates and polycarboxylates. There are various organic grinding aids, such as alkanolamines, glycols or phenolic compounds, used in the cement industry. This review is concerned with the following compounds: triethylenetetramine, tetraethylenepentamine, diethanolamine, triethanolamine, triisopropanolamine, ethyleneglycol, diethyleneglycol, aminoethylethanolamine, hydroxyethyl diethylenetriamine and phenol. (orig.)

  18. Analysis of cement superplasticizers and grinding aids a literature survey

    International Nuclear Information System (INIS)

    This literature survey reviews the methods for analysis of cement plasticizers and organic grounding aids in cement solutions in preparation of grouts/concrete and methods for determination of plasticizers and grinding aids in groundwater conditions. The survey focuses on three different types of superplasticizers: sulphonated naphthalene condensates, sulphonated melamine condensates and polycarboxylates. There are various organic grinding aids, such as alkanolamines, glycols or phenolic compounds, used in the cement industry. This review is concerned with the following compounds: triethylenetetramine, tetraethylenepentamine, diethanolamine, triethanolamine, triisopropanolamine, ethyleneglycol, diethyleneglycol, aminoethylethanolamine, hydroxyethyl diethylenetriamine and phenol. (orig.)

  19. Kinetics and Mechanisms of Phase Transformations Induced by Ball-Milling in Anatase TiO 2

    Science.gov (United States)

    Bégin-Colin, S.; Girot, T.; Le Caër, G.; Mocellin, A.

    2000-01-01

    Ball-milling is a way of inducing phase transformations, chemical reactions, and changes in the reactivity of solids. It is a complex process for which several models have been developed to predict the evolution of systems and to describe its physics. These models sometimes empirically need experimental data to be ascertained and to confirm general theories of system evolutions. In this work, we investigate the effect of two milling parameters, the powder to ball weight ratio R and the nature of the grinding media, on the kinetics of phase transformations in anatase TiO2 powder. These experiments established that R affects only the reaction rate. The kinetics are faster with alumina than with steel grinding tools for a given R, specific injected powers being similar. It has been demonstrated that the phase transformations induced by grinding TiO2 occur without fracturing of particles and mechanisms are commented upon.

  20. Microstructure evolution during spray rolling and heat treatment of 2124 Al

    International Nuclear Information System (INIS)

    Spray rolling is a strip-casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly remove the metal's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified strip. Spray rolling operates at a higher solidification rate than conventional twin-roll casting and is able to process a broader range of alloys at high production rates. A laboratory-scale strip caster was constructed and used to evaluate the interplay of processing parameters and strip quality for strips up to 200 mm wide and 1.6-6.4 mm thick. This paper examines microstructure evolution during spray rolling and explores how gas-to-metal mass flow ratio influences the microstructure and mechanical properties of spray-rolled 2124 Al. The influences of solution heat treatment and cold rolling on grain structure and constituent particle spheroidization are also examined

  1. Microstructure evolution during spray rolling and heat treatment of 2124 Al

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, K.M. [Industrial Technology Department, Idaho National Laboratory, Idaho Falls, ID 83415-2050 (United States)], E-mail: kevin.mchugh@inl.gov; Lin, Y.; Zhou, Y.; Johnson, S.B.; Delplanque, J.-P.; Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)

    2008-03-25

    Spray rolling is a strip-casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly remove the metal's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified strip. Spray rolling operates at a higher solidification rate than conventional twin-roll casting and is able to process a broader range of alloys at high production rates. A laboratory-scale strip caster was constructed and used to evaluate the interplay of processing parameters and strip quality for strips up to 200 mm wide and 1.6-6.4 mm thick. This paper examines microstructure evolution during spray rolling and explores how gas-to-metal mass flow ratio influences the microstructure and mechanical properties of spray-rolled 2124 Al. The influences of solution heat treatment and cold rolling on grain structure and constituent particle spheroidization are also examined.

  2. Ship Roll Damping Control

    DEFF Research Database (Denmark)

    Perez, Tristan; Blanke, Mogens

    2012-01-01

    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of difficulties associated with control system designs, which have proven to be far from trivial due to fundamental performance limitations and large variations of the spectral characteristics of wave-induced roll motion. This tutorial paper presents an account of the development of various ship roll motion control systems together with the challenges associated with their design. It discusses the assessment of performance and the applicability of different mathematical models, and it surveys the control methods that have been implemented and validated with full scale experiments. The paper also presents an outlook on what are believed to be potential areas of research within this topic.

  3. Improved Billet Shape Modeling in Optimization of the Hot Rod and Wire Rolling Process

    OpenAIRE

    Betshammar, Jan

    2006-01-01

    The hot rod and wire rolling process is widely used to produce rolled iron alloys in different shapes and dimensions. This industry has been under a constant development during the last decades. Today, complex geometries are produced at a high speed since it is possible to use several stands in each mill at the same time. A reason for the development is rising demands from customers. The most important demands are to save energy, to get better material properties and higher dimension accuracy...

  4. High coercivity induced by mechanical milling in cobalt ferrite powders

    Energy Technology Data Exchange (ETDEWEB)

    Ponce, A.S. [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Chagas, E.F., E-mail: efchagas@fisica.ufmt.br [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Prado, R.J. [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Fernandes, C.H.M.; Terezo, A.J. [Departamento de Química, Universidade Federal do Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150 Urca. Rio de Janeiro (Brazil)

    2013-10-15

    In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe{sub 2}O{sub 4} treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500 °C. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio M{sub R}/M{sub S} for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy, and vibrating sample magnetometry. The XPD analysis by the Williamson–Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples. - Highlights: • Magnetic behavior of milled CoFe{sub 2}O{sub 4} is studied. • The coercivity is increase of about 150%. • The remanence ratio are increase to all milled samples. • The strain and pinning effects are observed in milled samples.

  5. High coercivity induced by mechanical milling in cobalt ferrite powders

    International Nuclear Information System (INIS)

    In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500 °C. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio MR/MS for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy, and vibrating sample magnetometry. The XPD analysis by the Williamson–Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples. - Highlights: • Magnetic behavior of milled CoFe2O4 is studied. • The coercivity is increase of about 150%. • The remanence ratio are increase to all milled samples. • The strain and pinning effects are observed in milled samples

  6. Ship Roll Motion Control

    DEFF Research Database (Denmark)

    Perez, Tristan University of Newcastle

    2010-01-01

    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of deciencies in control system designs, which have proven to be far from trivial due to fundamental performance limitations. This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performance, the applicability of dierent models, and control methods that have been applied in the past.

  7. EVOLUTION OF THE AUSTENITE GRAIN SIZE DURING HOT STRIP ROLLING OF NIOBIUM MICROALLOYED STEELS

    Directory of Open Access Journals (Sweden)

    Antonio Augusto Gorni

    2015-06-01

    Full Text Available The occurrence of dynamic recrystallization in the intermediate stands of the Finishing Mill of a Hot Strip Mill promotes substantial softening of the rolling stock, a situation that can cause operational problems and even scrapping of the strip. The aim of this work was to identify the specific process conditions that can lead to this situation, which was carried out through the application of a microstructural evolution model. It was verified, for the specific conditions of the Cubatão Works of Usiminas, that this problem generally occurs during the processing of thin hot coils, with a relatively low Nb content and under rolling temperatures slightly lower than the normal range.

  8. Slitting criterion for various rolling speeds in MSR rolling process

    Directory of Open Access Journals (Sweden)

    A. Stefanik

    2008-03-01

    Full Text Available Purpose: The main idea of MSR technology is the capability of producing two, three, four and even five rods simultaneously from a single strip in a hot rolling process. Correctly separation of the joined strips is the one of the mainly problem in MSR process. Changing the rolling speed may causes easier of the strand division. In this paper results of the computer simulation of the double slitting rolling process were presented.Design/methodology/approach: For numerical modelling of the multi rolling process a computer program Forge 2005, based by the finished element method was used. As a slitting criterion normalised Cockroft – Latham criterion was used.Findings: For the analysis performed in this study, it was found that increasing of the rolling speed causes of increasing the normalized Cockroft – Latham criterion. For the small values of rolling velocity the strip separation was easier.Research limitations/implications: Multi Slit Rolling process is applied in ribbed rods rolling. Adjusting of the rolling speed in multi slit rolling process could improve of the slitting band to the separated strips.Originality/value: Incorrect construction or bad gap matching could cause lack of separation propelled slitting rolls. The separation of the band is effected by means of separating rollers, which shape must be properly designed to suit to the slitting pass. Changing of the rolling speed could improve of the separation to the single strips.

  9. Control system for the surface quality of hot-rolled metal

    International Nuclear Information System (INIS)

    Full text: The modern ideas about quality of products are based on the principle of absolute satisfaction of the requirements and recommendations of the buyer. The presence of surface defects of steel-smelting and rolling origin is characteristic for the production of hot-rolling mill. The automatic surface inspection system (ASIS) includes two digital line video cameras for the filming of the upper and lower surface of the flat bar, a block for illumination of the upper and lower surface of the flat bar and a computer equipment. A system which secures 100 % control of the upper and lower surface of the rolled metal, detects automatically and classifies the sheet defects in the real time mode, was mounted 2003 for the first time in the domestic practice at the hot rolling mill 2000 JSC «Novolipetsk Iron & Steel Corporation» (NISC). The whole assortment of the mill 2000 was divided into five groups according to the outward appearance of the surface. The work on identifying the defects of hot-rolled metal and on widening the data base of knowledge of ASIS was continued after the guarantee tests. More than ten thousand images of defects were added to the data base during the year. key words: hot-rolling sheet, surface quality control, data base of defects

  10. Automatic programming of grinding robot restoration of contours

    Directory of Open Access Journals (Sweden)

    Are Willersrud

    1995-07-01

    Full Text Available A new programming method has been developed for grinding robots. Instead of using the conventional jog-and-teach method, the workpiece contour is automatically tracked by the robot. During the tracking, the robot position is stored in the robot control system every 8th millisecond. After filtering and reducing this contour data, a robot program is automatically generated.

  11. 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.

  12. GRINDING OF SHAPED TOOLS ON CNC TOOL GRINDER

    Directory of Open Access Journals (Sweden)

    Ján Krá?

    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.

  13. Grinding performance of pellet prepared using nanosize ceria particles

    International Nuclear Information System (INIS)

    The cerium oxide particles of single crystal were obtained only by the combination of precipitation method and hydrothermal treatment at lower temperature than 200 deg. C. The particles showed plate-like shape even in the particle size of about 4 nm, and the plate-like plane was identified to be (1 1 1) from the observation of lattice images. By heating at 100-700 deg. C in air, the particle size was increased from about 4 to 60 nm maintaining the plate-like shape with elevating the temperature. These cerium oxide particles were applied as a fine abrasive grain for mirror grinding. We manufactured a grinding pellet, consisting of the plate-like cerium oxide particles, using electrophoretic deposition (EPD) phenomenon. It is called 'ceria EPD pellet'. As a result of grinding of quartz-crystal wafer using the ceria EPD pellet, fine mirror surface with roughness less than 1 nmRy was realized. Grinding efficiency of the ceria EPD pellet was fourth time as high as a silica EPD pellet

  14. 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.

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

    OpenAIRE

    Annabelle L. Grundy; Michelle K. McGinn

    2010-01-01

    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.

  16. Computer numerical control grinding of spiral bevel gears

    Science.gov (United States)

    Scott, H. Wayne

    1991-01-01

    The development of Computer Numerical Control (CNC) spiral bevel gear grinding has paved the way for major improvement in the production of precision spiral bevel gears. The object of the program was to decrease the setup, maintenance of setup, and pattern development time by 50 percent of the time required on conventional spiral bevel gear grinders. Details of the process are explained.

  17. Global analysis of aerodynamics deflectors efficiency in the grinding process

    Scientific Electronic Library Online (English)

    Rodrigo E., Catai; Eduardo C., Bianchi; Felipe M., Zilio; Ivan de D., Valarelli; Manoel C. de S., Alves; Leonardo R., Silva; Paulo R. de, Aguiar.

    2006-06-01

    Full Text Available The conventional grinding methods in some cases are not very efficient because the arising of thermal damages in the pieces is very common. Optimization methods of cutting fluid application in the grinding zone are essential to prevent thermal problems from interaction of the wheel grains with the w [...] orkpiece surface. The optimization can happen through the correct selection of the cut parameters and development of devices that eliminate air layer effects generated around the grinding wheel. This article will collaborate with the development of an experimentation methodology which allows evaluating, comparatively, the performance of the deflectors in the cutting region to minimize the air layer effect of the high speed of the grinding wheel. The air layers make the cutting fluid jet to dissipate in the machine. An optimized nozzle was used in order to compare the results with the conventional method (without baffles or deflectors) of cutting fluid application. The results showed the high eficciency of the deflectors or baffles in the finish results.

  18. Person og Rolle

    DEFF Research Database (Denmark)

    Szatkowski, Janek

    2011-01-01

    Distinktionen mellem person og rolle forslås som grundlag for et præcist og anlytisk anvendeligt begreb om performativitet. Begrebet tager sigte på at beskrive enkeltindividers og gruppers kommunikation med henblik på hvordan kommunikation etableres. Performativitet gør det muligt at iagttage den strukturelle kobling mellem psykiske stystemers bevidsthed og sociale systemers kommunikation, og derved åbne for en diskussion af hvordan værdier fungerer i en sådan kommunikation.

  19. Rolling Spot Welder

    Science.gov (United States)

    Wagner, Garret E.; Fonteyne, Steve L.

    1990-01-01

    Wheeled tool speeds tack-welding operations. Spotwelds foil to parts in preparation for brazing. Includes electrode wheel rolling across foil. Welding current in electrode pulsed as electrode moves along, making series of uniformly-spaced low-current spot welds.

  20. Lokalpolitikeres rolle og råderum

    DEFF Research Database (Denmark)

    Holm Pedersen, Lene; Houlberg, Kurt

    2013-01-01

    I en ny og omfattende undersøgelse fra KORA og CBS er alle landets lokalpolitikere blevet spurgt om, hvordan de oplever deres rolle og råderum. Undersøgelsen belyser blandt andet, hvordan arbejdsvilkår og indflydelsesmuligheder er i dag, og hvordan vilkår og muligheder er blevet ændret de senere år.

  1. Subsurface damage mechanism of high speed grinding process in single crystal silicon revealed by atomistic simulations

    International Nuclear Information System (INIS)

    Highlights: • Molecular dynamic model of nanoscale high speed grinding of silicon workpiece has been established. • The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation during high speed grinding process are thoroughly investigated. • Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle. • The hydrostatic stress and von Mises stress by the established analytical model are studied subsurface damage mechanism during nanoscale grinding. - Abstract: Three-dimensional molecular dynamics (MD) simulations are performed to investigate the nanoscale grinding process of single crystal silicon using diamond tool. The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation are studied. We also establish an analytical model to calculate several important stress fields including hydrostatic stress and von Mises stress for studying subsurface damage mechanism, and obtain the dislocation density on the grinding subsurface. The results show that a higher grinding velocity in machining brittle material silicon causes a larger chip and a higher temperature, and reduces subsurface damage. However, when grinding velocity is above 180 m s?1, subsurface damage thickness slightly increases because a higher grinding speed leads to the increase in grinding force and temperature, which accelerate dislocation nucleation and motion. Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle, that provides valuable reference for machining nanometer devices. The von Mises stress and the hydrostatic stress play an important role in the grinding process, and explain the subsurface damage though dislocation mechanism under high stress status. The dislocation nucleation and motion induced plastic deformation during grinding process can better reveal subsurface damage mechanism considering to stress and temperature acting on the dislocations

  2. Subsurface damage mechanism of high speed grinding process in single crystal silicon revealed by atomistic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China); Fang, Qihong, E-mail: fangqh1327@hnu.edu.cn [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China); Zhang, Liangchi [School of Mechanical and Manufacturing Engineering, The University of New South Wales, NSW 2052 (Australia); Liu, Youwen [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China)

    2015-01-01

    Highlights: • Molecular dynamic model of nanoscale high speed grinding of silicon workpiece has been established. • The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation during high speed grinding process are thoroughly investigated. • Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle. • The hydrostatic stress and von Mises stress by the established analytical model are studied subsurface damage mechanism during nanoscale grinding. - Abstract: Three-dimensional molecular dynamics (MD) simulations are performed to investigate the nanoscale grinding process of single crystal silicon using diamond tool. The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation are studied. We also establish an analytical model to calculate several important stress fields including hydrostatic stress and von Mises stress for studying subsurface damage mechanism, and obtain the dislocation density on the grinding subsurface. The results show that a higher grinding velocity in machining brittle material silicon causes a larger chip and a higher temperature, and reduces subsurface damage. However, when grinding velocity is above 180 m s{sup ?1}, subsurface damage thickness slightly increases because a higher grinding speed leads to the increase in grinding force and temperature, which accelerate dislocation nucleation and motion. Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle, that provides valuable reference for machining nanometer devices. The von Mises stress and the hydrostatic stress play an important role in the grinding process, and explain the subsurface damage though dislocation mechanism under high stress status. The dislocation nucleation and motion induced plastic deformation during grinding process can better reveal subsurface damage mechanism considering to stress and temperature acting on the dislocations.

  3. Micro-Plasto-Hydrodynamic Lubrication a Fundamental Mechanism in Cold Rolling

    DEFF Research Database (Denmark)

    Laugier, Maxime; Boman, Romain

    2014-01-01

    This paper presents recent investigations in Micro-Plasto-Hydrodynamic (MPH) lubrication. Industrial evidences of the existence of MPH lubrication mechanism for cold rolling processes are presented. A new lubrication model developed for strip drawing processes is then applied to predict the MPH lubrication initiation and MPH lubrication extension along the tool-piece solid contacts initially in boundary lubrication regime. Finally, it is shown how this new MPH lubrication model can be implemented in a cold rolling model to maximize mills capabilities, determine optimum rolling oils properties and predict roughness transfer.

  4. Effects of grinding on properties of Mg-PSZ ceramics prepared by the surface enrichment of zirconia powders

    International Nuclear Information System (INIS)

    Commercial grade zirconia powders of mean particle size of 3.21 microns were super-ground in wet condition in alcoholic medium in a Planetary Ball-Mill for 12-hours using a zirconia pot as well as balls, in order to avoid contaminations from the grinding media. Sedigraph analysis data show the mean particle sizes within the range of 0.4 to 0.2 micron. The super-ground zirconia powders were then treated with appropriate acid and alkali solutions in order to enrich the surfaces of zirconia powders. The chemical analysis reports depict the enrichment phenomena of the processed zirconia powders. Magnesium oxide of different mole percentages (3 to 9%) have been incorporated to the above super-ground and enriched zirconia powder and green specimens were prepared by pressing with a suitable pressure of 200 MPa to yield the green compaction density of 3.06 gm/cm3. The compacted green specimens were sintered without pressure at 1,480 C in air followed by normal cooling. X-ray diffraction patterns of the above sintered and cooled specimens have confirmed the formation of Mg-PSZ ceramics with 40% tetragonal phase. The sintered PSZ-products have shown very good surface properties but at the cost of transverse rupture strength. The effects of grinding were observed on the above Mg-PSZ ceramics which exhibit very little change in the tetragonal phase even after 30-minutes of grinding with a 60-mesh diamond wheel at a normal pressure of 4 kg/cm2

  5. Simulation-Assisted Evaluation of Grinding Circuit Flowsheet Design Alternatives: Aghdarreh Gold Ore Processing Plant / Ocena Alternatywnych Schematów Technologicznych Procesu Rozdrabniania W Zak?adach Przeróbki Rud Z?ota W Aghdarreh, Z Wykorzystaniem Metod Symulacji

    Science.gov (United States)

    Farzanegan, A.; Ghalaei, A. Ebtedaei

    2015-03-01

    The run of mine ore from Aghdarreh gold mine must be comminuted to achieve the desired degree of liberation of gold particles. Currently, comminution circuits include a single-stage crushing using a jaw crusher and a single-stage grinding using a Semi-Autogenous Grinding (SAG) mill in closed circuit with a hydrocyclone package. The gold extraction is done by leaching process using cyanidation method through a series of stirred tanks. In this research, an optimization study of Aghdarreh plant grinding circuit performance was done to lower the product particle size (P80) from 70 ?m to approximately 40 ?m by maintaining current throughput using modeling and simulation approach. After two sampling campaigns from grinding circuit, particle size distribution data were balanced using NorBal software. The first and second data sets obtained from the two sampling campaigns were used to calibrate necessary models and validate them prior to performing simulation trials using MODSIM software. Computer simulations were performed to assess performance of two proposed new circuit flowsheets. The first proposed flowsheet consists of existing SAG mill circuit and a new proposed ball mill in closed circuit with a new second hydrocyclone package. The second proposed flowsheet consists of existing SAG mill circuit followed by a new proposed ball mill in closed circuit with the existing hydrocyclone package. In all simulations, SAGT, CYCL and MILL models were selected to simulate SAG mill, Hydrocyclone packages and ball mill units. SAGT and MILL models both are based on population balance model of grinding process. CYCL model is based on Plitt's empirical model of classification process in hydrocyclone units. It was shown that P80 can be reduced to about 40 ?m and 42 ?m for the first and second proposed circuits, respectively. Based on capital and operational costs, it can be concluded that the second proposed circuit is a more suitable option for plant grinding flowsheet modification. Surowy urobek z kopalni rud z?ota Aghdarreh musi najpierw zosta? poddany rozdrobnieniu, aby zapewni? efektywniejsze uwalnianie cz?steczek z?ota. W chwili obecnej obiegi rozdrabniania obejmuj? kruszenie jednostopniowe z wykorzystaniem kruszarek szcz?kowych oraz kruszenie jednostopniowe z u?yciem kruszarek pó?automatycznych w obiegu zamkni?tym z hydrocyklonem. Odzysk z?ota odbywa si? przy zastosowaniu procesu ?ugowania, z zastosowaniem metody cyjankowej w szeregu mieszalników. W pracy tej przeprowadzono optymalizacj? procesu rozdrabniania rud w zak?adach przeróbczych Aghdarreh prowadzonego w celu zmniejszenia rozmiarów uzyskiwanych cz?steczek z?ota (Ps0) z 70 ?m do ok. 40 ?m poprzez zapewnienie ci?g?o?ci procesu, z wykorzystaniem metod modelowania i symulacji. Na podstawie dwóch zestawów próbek z ci?gu technologicznego rozdrabniania, rozk?ady wielko?ci cz?stek zosta?y statystycznie zrównowa?one z wykorzystaniem oprogramowania NorBal. Pierwszy i drugi zbiór danych otrzymanych na podstawie dwóch zestawów próbek wykorzystany zosta? do kalibracji i walidacji modeli, przed przyst?pieniem do w?a?ciwych bada? symulacyjnych z u?yciem oprogramowania MODSIM. Symulacje komputerowe przeprowadzono w celu oceny wydajno?ci dwóch proponowanych ci?gów technologicznych. Pierwszy ci?g obejmuje istniej?ce kruszarki pó?automatyczne i nowo proponowan? kruszark? kulow? pracuj?c? w obiegu zamkni?tym z hydrocyklonem. Drugi rozwa?any ci?g stanowi istniej?ca kruszarka pó?automatyczna, nast?pnie proponowana kruszarka kulowa pracuj?ca w obiegu zamkni?tym z istniej?cym hydrocyklonem. We wszystkich symulacjach bazowano na modelach SAGT, CYCL i MILL do symulacji pracy kruszarek pó?automatycznych, pakietu hydrocyklonu oraz pojedynczych kruszarek. Modele SAGT i MILL oparte s? na modelu zrównowa?onej populacji w procesie rozdrabniania. Model CYCL opiera si? na empirycznym modelu klasyfikacji Plitta zastosowanym do hydrocyklonów. Wykazano, ?e rozmiar cz?stek zmniejszony zosta

  6. Modeling, simulation and identification for control of tandem cold metal rolling

    Scientific Electronic Library Online (English)

    Péricles Guedes, Alves; José Adilson de, Castro; Luciano Pessanha, Moreira; Elder Moreira, Hemerly.

    2012-12-01

    Full Text Available This paper describes a modeling procedure for tandem cold metal rolling, including the linearization step and system identification for control. The tandem cold rolling process is described by a mathematical model based on algebraic equations developed for control purposes and empirical relations. A [...] state-space model is derived and detailed analyses in open loop are presented, concerning the sensitivity with regard to the variations in process parameters and results for the application of a new subspace identification method are compared with classical methodologies. Therefore, this work intents to be a contribution for developments in new control strategies for tandem cold rolling process that offer the potential to reduce the design efforts, the commissioning time and maintenance in rolling mills. The preliminary results obtained with this model have shown reasonable agreement with operational data presented at literature for industrial cold rolling process.

  7. Microstructure Evolution During Spray Rolling and Heat Treatment of 2124 Al

    Energy Technology Data Exchange (ETDEWEB)

    K.M. McHugh; Y. Lin; Y. Zhou; S.B. Johnson; J.P. Delplanque; E.J. Lavernia

    2006-09-01

    Spray rolling is a strip casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly move an alloy’s latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified product. While similar in many ways to twin-roll casting, spray rolling is able to process a broader range of alloys and operates at a higher production rate. A laboratory-scale strip caster has been constructed at INL and used to evaluate the interplay of processing parameters and strip quality while producing strips up to 200 mm wide and 1.6 – 6.4 mm thick. Plans are underway to scale to 600 mm width and demonstrate steady-state operation. As-spray-rolled strip is characterized by a flat, uniformly thick profile with minimal porosity or segregation. This paper examines how processing parameters influence the microstructure transformations that take place during spray rolling and post-deposition heat treatment of 2124 Al.

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

    Directory of Open Access Journals (Sweden)

    R. ?wi?cik

    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.

  9. Investigation of the maintenance organisation for hot rolling mills

    OpenAIRE

    P.K. Pretorius; Visser, J.K.

    2001-01-01

    ENGLISH ABSTRACT: Production systems have undergone dramatic changes in recent years. Many companies have implemented new technologies such as flexible manufacturing systems. There is therefore a shift in focus to maintenance and the effective management thereof. Maintenance is a dynamic activity and is comprised of a large number of interacting variables. An effective maintenance organisation is required to control these variables .
    This paper discusses the building of a ...

  10. Walk and roll robot

    Science.gov (United States)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A mobile robotic unit features a main body, a plurality of legs for supporting the main body on and moving the main body in forward and reverse directions about a base surface, and a drive assembly. According to an exemplary embodiment each leg includes a respective pivotal hip joint, a pivotal knee joint, and a wheeled foot adapted to roll along the base surface. Also according to an exemplary embodiments the drive assembly includes a motor operatively associated with the hip and knee joints and the wheeled foot for independently driving pivotal movement of the hip joint and the knee joint and rolling motion of the wheeled foot. The hip joint may include a ball-and-socket-type joint interconnecting top portion of the leg to the main body, such that the hip joint is adapted to pivot said leg in a direction transverse to a forward-and-reverse direction.

  11. Tenascin Supports Lymphocyte Rolling

    OpenAIRE

    Clark, Rachael A; Erickson, Harold P.; Springer, Timothy A

    1997-01-01

    Tenascin is a large extracellular matrix molecule expressed at specific sites in the adult, including immune system tissues such as the bone marrow, thymus, spleen, and T cell areas of lymph nodes. Tenascin has been reported to have both adhesive and anti-adhesive effects in static assays. We report here that tenascin supports the tethering and rolling of lymphocytes and lymphoblastic cell lines under flow conditions. Binding was calcium dependent and was not inhibited by treatment of ly...

  12. Evolution of topography and material removal during nanoscale grinding

    Science.gov (United States)

    Eder, S. J.; Cihak-Bayr, U.; Vernes, A.; Betz, G.

    2015-11-01

    In this work we perform molecular dynamics simulations to quantify and parametrize the evolution of a bcc Fe work piece topography during nanometric grinding with multiple hard abrasive particles. The final surface quality depends on both the normal pressure and the abrasive geometry. We fit the time development of the substrate’s root mean squared roughness to an exponential function, allowing the definition of a run-in regime, during which the surface ‘forgets’ about its initial state, and a steady-state regime where the roughness no longer changes. The time constants associated with smoothing and material removal are almost inversely proportional to each other, highlighting the distinctiveness of these two simultaneously occurring processes. We also describe an attempt to reduce the time required to achieve the smoothest possible surface finish by periodically re-adjusting the normal pressure during the grinding process.

  13. Study of thresholds to burning in surface grinding process

    OpenAIRE

    P. R. Aguiar; F. R. L. Dotto; E. C. Bianchi

    2005-01-01

    This work aims at finding out the threshold to burning in surface grinding process. Acoustic emission and electric power signals are acquired from an analog-digital converter and processed through algorithms in order to generate a control signal to inform the operator or interrupt the process in the case of burning occurrence. The thresholds that dictate the situation of burn and non-burn were studied as well as a comparison between the two parameters was carried out. In the experimental work...

  14. Control of Grinding Temperature by High Speed Air Jets

    OpenAIRE

    TORRANCE, ARCHIBALD ANDREW; MURRAY, DARINA BRIDGET; BABIC, DARKO M.

    2004-01-01

    Grinding, like other abrasive processes, may generate high local temperatures along the arc of cut. These can cause various forms of surface damage in the most sensitive finishing phase of the manufacturing cycle. Traditional cooling methods based on large amounts of water-oil emulsions can be both ineffective and environmentally unacceptable. A new approach to this problem has been devised utilizing the high penetrative power of fast air jets combined with a water/soap mist to greatly improv...

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

    OpenAIRE

    Yury GUTSALENKO

    2012-01-01

    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

  16. Characterization of the grinding behaviour in a single particle impact device: studies on pharmaceutical powders.

    Science.gov (United States)

    Meier, Matthias; John, Edgar; Wieckhusen, Dierk; Wirth, Wolfgang; Peukert, Wolfgang

    2008-05-10

    The grinding behaviour of different materials can be described by the two material parameters fMat and Wm,min [Vogel, L., Peukert, W., 2003. Breakage behaviour of different materials-construction of a mastercurve for the breakage probability. Powder Technol. 129, 101-110]. fMat describes the resistance of particulate material against fracture in impact comminution, Wm,min characterizes the specific energy which a particle can take up without comminution. The material parameters are determined experimentally by single particle impact tests. This concept is also applicable to pharmaceutical powders, as will be shown in this work. A device is presented for the characterization of particles with sizes down to a few 10 microm. Particles are dispersed and accelerated in an air stream which is flowing against an impact plate. The impact velocity is controlled by the air flow. An LDA system enables the measurement of particle velocities. The results obtained with this jet mill are in accordance to those obtained from another single particle impact device used by Vogel and Peukert, in which the influence of fluid flow is completely avoided. Since the new device is especially designed for finer powders, it will allow a more detailed analysis of the material parameters at smaller particle sizes. Additionally, a new analysis method has been developed in order to determine the breakage probability not from sieve analysis but from laser light diffraction (LLD) data by using a population balance. PMID:18400475

  17. Slitting criterion for various rolling speeds in MSR rolling process

    OpenAIRE

    Stefanik, A.

    2008-01-01

    Purpose: The main idea of MSR technology is the capability of producing two, three, four and even five rods simultaneously from a single strip in a hot rolling process. Correctly separation of the joined strips is the one of the mainly problem in MSR process. Changing the rolling speed may causes easier of the strand division. In this paper results of the computer simulation of the double slitting rolling process were presented.Design/methodology/approach: For numerical modelling of the multi...

  18. 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.

  19. Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding

    Directory of Open Access Journals (Sweden)

    A. Pribulová

    2010-04-01

    Full Text Available Foundry dust can be divided into three groups: metallic dust with Fe content over 70%, mixed dust with Fe or SiO2 content between 10 –70% and sand wastes with minimum content of SiO2 about 70%. Dust from castings grinding with high Fe content (87.9% is still landfillin Slovakia. The aim of experiments with dust from grinding has been to find the cheapest way of dust agglomeration with minimumamount of binder because of melting in the electric induction furnace. The dust was pelletized and briquetted and as binders bentonite, water glass and cement were used. Briquettes made from dust from grinding with addition of water glass got compression strength after three months on the air about 82 kPa. Briquettes with addition of water glass were melted together with cast iron in electric induction furnace. Yield of metal from briquettes was around 80% and slag quantity around 4% (without briquettes the slag quantity was 1.4%.

  20. Relationships of damaged starch granules and particle size distribution with pasting and thermal profiles of milled MR263 rice flour.

    Science.gov (United States)

    Asmeda, R; Noorlaila, A; Norziah, M H

    2016-01-15

    This research was conducted to investigate the effects of different grinding techniques (dry, semi-wet and wet) of milled rice grains on the damaged starch and particle size distribution of flour produced from a new variety, MR263, specifically related to the pasting and thermal profiles. The results indicated that grinding techniques significantly (pCorrelation analysis revealed that percentage of damaged starch granules had a significant, negative relationship with pasting temperature while average particle size distribution had a significant, strong negative relationship with gelatinization temperature. PMID:26258700

  1. Rolling motion in moving droplets

    Indian Academy of Sciences (India)

    Sumesh P Thampi; Rama Govindarajan

    2015-03-01

    Drops moving on a substrate under the action of gravity display both rolling and sliding motions. The two limits of a thin sheet-like drop in sliding motion on a surface, and a spherical drop in roll, have been extensively studied. We are interested in intermediate shapes. We quantify the contribution of rolling motion for any intermediate shape, and recently obtained a universal curve for the amount of roll as a function of a shape parameter using hybrid lattice Boltzmann simulations. In this paper, we discuss the linear relationship which is expected between the Capillary and Bond numbers, and provide detailed confirmation by simulations. We also show that the viscosity of the surrounding medium can qualitatively affect dynamics. Our results provide an answer to a natural question of whether drops roll or slide on a surface and carry implications for various applications where rolling motion may or may not be preferred.

  2. Tuning the length dispersion of multi-walled carbon nanotubes by ball milling

    OpenAIRE

    László Forró; Richard Gaal; Claudio Grimaldi; Marijana Mioni?; Primož Rebernik Ribi?; Rita Smajda; Arnaud Magrez

    2013-01-01

    The statistical analysis of the length distribution of catalytic chemical vapour deposition synthesized multi-walled carbon nanotubes cut by planetary ball milling is reported. The nanotube lengths follow a log-normal distribution in a broad range of grinding time and rotational speed. We show that the scale parameter of the distribution, which equals the mean of the natural logarithm of the tube lengths, decreases linearly with the product of the duration time and the rotational speed. This ...

  3. Twin roll casting of magnesium alloys with high aluminum contents

    Directory of Open Access Journals (Sweden)

    H. Watari

    2006-08-01

    Full Text Available Purpose: The purpose of the work is to establish a manufacturing process and technology to facilitate theeconomical manufacture of high-quality magnesium sheet alloys with high aluminum contents, such as AZ61and AZ91. The aim of the work is to establish a twin roll casting technology to facilitate the manufacture ofAZ61 and AZ91 magnesium sheet alloys economically whilst maintaining high quality.Design/methodology/approach: A horizontal type twin roll caster was used to manufacture thin magnesium alloysheets of AZ61 and AZ91. Pair of copper alloy roll and pure copper roll was used for the horizontal type twin roll caster.A closed type tundish was set to the roll caster to keep stable contact of molten magnesium with upper and lower rolls.Findings: The experiment results clarified that AZ61 and AZ91 sheets can be manufactured by twin roll castingprocess. The product sheet thickness in the present experiment is 2.0 to 4.5 mm for AZ91, 2.5 to 5.0mm forAZ61. Mill stiffness and a method of predicting the cast sheet’s thickness were investigated to determine theappropriate manufacturing conditions. The microstructure of AZ61 cast strips was equiaxed structure and thecrystal sizes are different depending on cross section observed. The dendric and equiaxed microstructure wereseen in the microstructure of AZ91 cross section. The intermetllic Mg17Al12 was seen in the grain boundary inAZ91 when roll speed was very slow. The grain size of the manufactured wrought magnesium alloys sheet wasless than 10 micrometers. The obtained magnesium alloy sheet exhibited an equivalent limiting drawing ratio ina warm-drawing test. The limiting drawing ratio of AZ61 was 2.6 and 2.4 for AZ91.Research limitations/implications: The suitable roll speed was from 9m/min to 15m/min in manufacturingAZ91 and AZ61 strip using copper alloy rolls. When in use of pure copper roll, strips were cast between 6m/minand 20m/min for manufacturing AZ61 and AZ91. The superheats in the experiment were 15ºC and 30ºC. Thecast strips should be hot rolled at 300ºC.Originality/value: value In this experiment, it is clarified that AZ61, AZ91 sheets can be manufactured by twinroll casting. These cast sheet can be hot rolled and the manufacturing process by twin roll casting enable tomanufacure thin magnesium sheet alloys with high aluminum contents. It has been found that the manufacturedcast AZ61 and AZ91 have good formability by a warm deep drawing test.

  4. Isoflavone profile in soymilk as affected by soybean variety, grinding, and heat-processing methods.

    Science.gov (United States)

    Zhang, Yan; Chang, Sam K C; Liu, Zhisheng

    2015-05-01

    Isoflavones impart health benefits and their overall content and profile in foods are greatly influenced at each step during processing. In this study, 2 soybean varieties (Prosoy and black soybean) were processed with 3 different grinding (ambient, cold, and hot grinding) and heating methods (traditional stove cooking, 1-phase UHT, and 2-phase UHT) for soymilk making. The results showed after cold, ambient, and hot grinding, the total isoflavones were 3917, 5013, and 5949 nmol/g for Prosoy; the total isoflavones were 4073, 3966, and 4284 nmol/g for black soybean. Grinding could significantly increase isoflavone extraction. The grinding process had a destructive effect on isoflavones and this effect varied with grinding temperature. Different heating methods had different effects on different isoflavone forms. Two soybean varieties showed distinct patterns with respect to the change of isoflavone profile during processing. PMID:25827234

  5. / Analysis of the performance of superabrasive and alumina grinding wheels with different bonds and machining conditions

    Scientific Electronic Library Online (English)

    Eduardo Carlos, Bianchi; Paulo Roberto de, Aguiar; Rodrigo Daun, Monici; Luiz, Daré Neto; Leonardo Roberto da, Silva.

    2003-06-01

    Full Text Available This paper presents a review of researches on CBN (cubic boron nitride) grinding wheels with the purpose of identifying the state of art in abrasive machining and serving as the basis for future researches and laboratory tests. The scientific studies investigated here report on interesting results i [...] nvolving grinding, published by Brazilian and foreign authors. The methods and the results are presented and discussed. In addition, a grinding setup is presented which provides more reliable experimental results about the surface integrity of fragile materials. This setup was obtained for grinding tests in several grinding conditions during the wheel service life, using alumina and vitrified and resin bond CBN grinding wheels. Results of cutting force, surface roughness and G ratio are also presented and discussed. They confirm the excellent machining capacity of the CBN wheel, with stable behavior in cutting force and roughness results during the tests. The G ratio values are in agreement with the results found by other researchers.

  6. Research on automatic loading & unloading technology for vertical hot ring rolling process

    Directory of Open Access Journals (Sweden)

    Xiaokai Wang

    2015-01-01

    Full Text Available The automatic loading & unloading technology is the key to the automatic ring production line. In this paper, the automatic vertical hot ring rolling (VHRR process is taken as the target, the method of the loading & unloading for VHRR is proposed, and the mechanical structure of loading & unloading system is designed, The virtual prototype model of VHRR mill and loading & unloading mechanism is established, and the coordinated control method of VHRR mill and loading & unloading auxiliaries is studied, the movement trace and dynamic characteristic of the critical components are obtained. Finally, a series of hot ring rolling tests are conducted on the VHRR mill, and the production rhythm and the formed rings' geometric precision are analysed. The tests results show that the loading & unloading technology can meet the high quality and high efficiency ring production requirement. The research conclusions have practical significance for the large-scale automatic ring production.

  7. Microstructural Characterization of Calcite-Based Powder Materials Prepared by Planetary Ball Milling

    Directory of Open Access Journals (Sweden)

    Wen-Tien Tsai

    2013-08-01

    Full Text Available In this work, a planetary ball milling was used to modify the surface properties of calcite-based material from waste oyster shell under the rotational speed of 200–600 rpm, grinding time of 5–180 min and sample mass of 1–10 g. The milling significantly changed the microstructural properties of the calcite-based minerals (i.e., surface area, pore volume, true density, and porosity. The surface characterization of the resulting powder should be macroporous and/or nonporous based on the nitrogen adsorption/desorption isotherms. Under the optimal conditions at the rotational speed of 400 rpm, grinding time of 30 min and sample mass of 5 g, the resulting calcite-based powder had larger specific surface area (i.e., 10.64 m2·g?1 than the starting material (i.e., 4.05 m2·g?1. This finding was also consistent with the measurement of laser-diffraction (i.e., 9.7 vs. 15.0 ?m of mean diameter. In addition, the results from the scanning electron microscope (SEM observation indicated that surface roughness can be enhanced as particle size decreases as a result of particle-particle attrition. Thus, grinding the aquacultural bioresource by a high-energy ball milling can create the fine materials, which may be applied in the fields of inorganic minerals like aggregate and construction material.

  8. Microstructural Characterization of Calcite-Based Powder Materials Prepared by Planetary Ball Milling

    OpenAIRE

    Wen-Tien Tsai

    2013-01-01

    In this work, a planetary ball milling was used to modify the surface properties of calcite-based material from waste oyster shell under the rotational speed of 200–600 rpm, grinding time of 5–180 min and sample mass of 1–10 g. The milling significantly changed the microstructural properties of the calcite-based minerals (i.e., surface area, pore volume, true density, and porosity). The surface characterization of the resulting powder should be macroporous and/or nonporous based on the nitrog...

  9. The influence of the shape of grooves on the behavior of internal material discontinuities in continuous S355J2G3 steel strands during rolling

    Directory of Open Access Journals (Sweden)

    H. Dyja

    2014-10-01

    Full Text Available The article discusses problems related to the influence of rolling processes on the process of closing of internal discontinuities in continuous castings during rolling in shape grooves. Numerical modelling of the process of rolling 160 × 160 mm continuous S355J2G3 steel strands was carried out using the Forge 2008R software program. The experimental studies were conducted in a D150 laboratory rolling mill. Holes simulating material discontinuities were examined. In numerical and experimental studies, in steel samples after rolling in the third rolling stand, the defects were closing in 100 % on average. It was stated that the speed of closing of material discontinuities in feedstock is strongly influenced by the shape of the rolling groove.

  10. Effect of Cooling Environment on Grinding Performance of Nickel Based Superalloy Inconel 718

    OpenAIRE

    Raju S. Pawade; Arvind Chavan; Pankaj Chitalkar; Sandeep Huddedar

    2012-01-01

    The study presents the experimental investigation of surface grinding of superalloy Inconel 718. The grinding performance in terms of grinding force, surface roughness and surface topography were examined by conducting statistical experiments. The parameters that have been chosen as control factors are: table speed, infeed, grit size and the type of lubricant. An L27 orthogonal array experiments were conducted. The results show that the grit size and infeed are the most significant para...

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

    DEFF Research Database (Denmark)

    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 prog...

  12. Optimization of mill performance by using online ball and pulp measurements

    Scientific Electronic Library Online (English)

    B., Clermont; B., de Haas.

    2010-03-01

    Full Text Available Ball mills are usually the largest consumers of energy within a mineral concentrator. Comminution is responsible for 50% of the total mineral processing cost. In today's global markets, expanding mining groups are trying to optimize mill performances. Since comminution is concerned with liberating v [...] aluable minerals for recovery in the separation process, it is crucial to run the mills at the best operating conditions which lead to good liberation at competitive throughputs with minimum costs (energy and wear). The high availability of the equipment is also essential to maximize production and profit. To reach this key objective, continuous and reliable information about the mill operation is vital. An innovative tool which can deliver information about in-mill dynamics has been developed by Magotteaux. It can provide online and accurate measurements of the degree of grinding ball fill and pulp position for timely decision making and actions. This tool could be used on its own or linked to an automatic grinding ball loading system named Magoload . Therefore, ball load could be kept constant by using direct measurement. This article describes the Sensomag and presents some of the major improvements that can be achieved with it. Some other promising avenues are still to be explored.

  13. Nano ?nish 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 ?nishing of hard and brittle materials with nano-surface ?nish, high tolerance and accuracy. Grinding with superabrasive wheels is an excellent way to produce ultraprecision surface ?nish. 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 ?nish 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 ?nish. 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 in?uence on surface ?nish.

  14. Imaging subsurface damage of grinded fused silica optics by confocal fluorescence microscopy

    International Nuclear Information System (INIS)

    We report an experimental investigation of fluorescence confocal microscopy as a tool to measure subsurface damage on grinded fused silica optics. Confocal fluorescence microscopy was performed with an excitation at the wavelength of 405 nm on fixed abrasive diamond grinded fused silica samples. We detail the measured fluorescence spectrums and compare them to those of oil based coolants and grinding slurries. We evidence that oil based coolant used in diamond grinding induces a fluorescence that marks the subsurface damages and eases its observation. Such residual traces might also be involved in the laser damage process. (authors)

  15. Research on Optimization of Plunge Centerless Grinding Process using Genetic Algorithm and Response Surface Method

    Directory of Open Access Journals (Sweden)

    Phan Bui Khoi

    2015-03-01

    Full Text Available This paper presents the research on optimization of plunge centerless grinding process when grind 20X – carbon infiltration steel (?OCT standard - Russia to achieve minimum of roundness error value. The input parameters are center height angle of the workpiece ( ? , longitudinal grinding wheel dressing feed-rate ( Ssd , plunge feed-rate ( k S and control wheel velocity ( dd v . Using the result of 29 runs in Central Composite Design matrix to given the second order roundness error model. Genetic algorithm and Response surface method were used to focus on determination of optimum centerless grinding above parameters for minimization of roundness error for each methods.

  16. 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 performance of nano-particles, the ratio of heat delivered by grinding media was increased, leading to lower temperature in the grinding zone. Results demonstrate that nano-particle jet MQL has satisfactory cooling performance as well as a promising future of extensive application. PMID:23763268

  17. 9 CFR 381.159 - Poultry rolls.

    Science.gov (United States)

    2010-01-01

    ...INSPECTION AND CERTIFICATION POULTRY PRODUCTS INSPECTION REGULATIONS...Composition § 381.159 Poultry rolls. (a) Binders...permitted for use as binders in poultry rolls: transglutaminase enzyme...the product; e.g., “Turkey Roll-Gelatin Added.”...

  18. Rolling friction of adhesive microspheres

    International Nuclear Information System (INIS)

    The rolling friction of adhesive microspheres is an important quantity as it determines the strength and stability of larger aggregates. Current models predict rolling forces that are 1 to 2 orders of magnitude smaller than observed experimentally. Starting from the well-known Johnson–Kendall–Roberts (JKR) contact description, we derive an analytical theory for the rolling friction based on the concept of adhesion hysteresis, e.g. a difference in apparent surface energies for opening/closing cracks. We show how adhesion hysteresis causes the pressure distribution within the contact to become asymmetrical, leading to an opposing torque. Analytical expressions are derived relating the size of the hysteresis, the rolling torque, and the rolling displacement, ?. We confirm the existence of a critical rolling displacement for the onset of rolling, the size of which is set by the amount of adhesion hysteresis and the size of the contact area. We demonstrate how the developed theory is able to explain the large rolling forces and particle-size dependence observed experimentally. Good agreement with experimental results is achieved for adhesion hysteresis values of (??/?) ? 3 for polystyrene, and (??/?) ? 0.5 for silicates, at crack propagation rates of 0.1 µm s?1 and 1–10 µm s?1, respectively. (paper)

  19. Effect of Milling Time on Al-Fe-Cr-20 Wt. % Al2O3composite Prepared Through Ball Milling

    Directory of Open Access Journals (Sweden)

    Hameedur Rehman Khan

    2014-07-01

    Full Text Available One of the main challenges towards achieving a homogeneous distribution of the ceramic phase in the metal matrix composites is agglomeration of the reinforcement particles. Mechanical alloying is among the most important processing techniques used for manufacturing of metal matrix composites (MMCs.An attempt was made to synthesize Al-Fe-Cr-Al2O3composites synthesized through mechanical alloying. Al2O3 is used as reinforcement. Ethanol (5 wt. % has been used as a process control agent (PCA. Mechanical alloying is carried out in a conventional ball mill using stainless steel grinding media at 115 rpm in the argon environment for 5h, 10h and 15h. The ball to powder weight ratio was maintained at 20:1. The characterization of the ball milled powder was followed by scanning electron microscopy (SEM. Showed the formation of a homogeneous phase for all compositions after milling for 15 h. XRD patterns were recorded for the milled powders, and analyzed using Williamson–Hall method and Scherrer’s equation to determine the lattice strain and grain size.EDX is performed to check the contamination of composites during the mechanical alloying.XRD is used to study structural evolution of synthesized aluminium composite. Effect of milling time is investigated on synthesized Al-Fe-Cr-20 wt. % Al2O3 composites.

  20. 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.

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

    International Nuclear Information System (INIS)

    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 particleclose 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

  2. Chatter Prediction in End Milling by FNN Model with Pruning

    Science.gov (United States)

    Hino, Junichi; Okubo, Seiichi; Yoshimura, Toshio

    This paper is concerned with a study of chatter prediction in high-speed end milling operations. Chatter vibration occurring in mechanical machining gives rise to poor surface finish and dimensional inaccuracy in machined parts, reduction of tool life, and even damages machine tools. Various studies of its prediction and avoidance have been carried out over the last several decades. The purpose of this study is to develop an expert system for predicting chatter vibrations in high-speed end milling using wavelet transform and fuzzy neural network models with pruning. The FNN model employed here uses a pruning process which reduces a neural network to its most effective size. The amount of learning for convergence of a pruned network is reduced in comparison with an initial network. The proposed method is applied to a jig grinding machine, and the results demonstrate the effectiveness of the chatter prediction procedure.

  3. 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.

  4. 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.

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

    Scientific Electronic Library Online (English)

    Foteini, Kontoleontos; Petros, Tsakiridis; Apostolos, Marinos; Nikolaos, Katsiotis; Vasileios, Kaloidas; Margarita, Katsioti.

    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 c [...] ements 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).

  6. 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.

  7. 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.  

  8. Improving the quality of rolled pipe steel products by minimizing the bending of the ends of plates

    Science.gov (United States)

    Salganik, V. M.; Chikishev, D. N.; Denisov, S. V.; Stekanov, P. A.; Shmakov, A. V.; Fomichev, A. V.

    2013-11-01

    The causes of the vertical bending of the front ends of plates during hot rolling are revealed. A finite-element mathematical model is developed to describe the state of stress of the metal in an asymmetric deformation zone with allowance for solving a temperature problem, and the model is adapted to the conditions of the 5000 rolling mill in OAO MMK. It is found that, in rolling with mismatched work roll speeds, the direction of bending of the front strip end is determined by the strip thickness and the deformation zone shape. The main cause of the bending of the front plate end at the stage of finishing stage of rolling is shown to be the difference between the roller bed level and the rolling line. New asymmetric deformation regimes are developed with allowance for the effect of the deformation zone shape on the direction of bending of the front strip end. The developed technological regimes of asymmetric rolling make it possible to decrease the mill downtime because of the bending of the breakdown bar ends and to reduce the metal volume rejected because of violated temperature regimes of the thermomechanical treatment of plates.

  9. An investigation of the degradation products of coals with different degrees of grinding by mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zuhravlev, V.I.; Bychev, M.I.; Glushchenko, I.M.; Malevich, V.K.

    1983-01-01

    Investigations of the group chemical composition of the products of mechanodestruction liberated into the vapor phase from coals of various degrees of grinding have been made by the mass-spectrometric method. Some relationships have been found between the chemical composition of the volatile products liberated from the coals and the degrees of grinding of these coals.

  10. Diamond blade grinding as a means for removing surface contamination from concrete

    International Nuclear Information System (INIS)

    The use of a highway grinding unit for the decontamination of a 5,000 square foot surface is described. The type of equipment presently in use is described. Performance characteristics, waste collection and water usage are commented on. Variables in blade design are discussed. Feasibility of the grinding technique for water soluble contaminants and vertical surfaces is referred to

  11. Roll Control in Fruit Flies

    CERN Document Server

    Beatus, Tsevi; Cohen, Itai

    2014-01-01

    Due to aerodynamic instabilities, stabilizing flapping flight requires ever-present fast corrective actions. Here we investigate how flies control body roll angle, their most susceptible degree of freedom. We glue a magnet to each fly, apply a short magnetic pulse that rolls it in mid-air, and film the corrective maneuver. Flies correct perturbations of up to $100^{\\circ}$ within $30\\pm7\\mathrm{ms}$ by applying a stroke-amplitude asymmetry that is well described by a linear PI controller. The response latency is $\\sim5\\mathrm{ms}$, making the roll correction reflex one of the fastest in the animal kingdom.

  12. Performance of direct and reverse Samarco grinding circuits / Desempenho dos circuitos de moagem direto e inverso da Samarco

    Scientific Electronic Library Online (English)

    Andreia Carolina, Rosa; Homero, Delboni Jr.

    2014-06-01

    Full Text Available Os aspectos operacionais entre as configurações de circuito fechado de moagem em moinhos de bolas, quais sejam, os circuitos direto e inverso, foram analisados comparativamente. Foram realizadas amostragens no circuito industrial de moagem primária do Concentrador I de Germano, operando sob ambas as [...] configurações, além de serem analisados os dados históricos industriais dos Concentradores I e II. Por fim, foram realizados ensaios de moagem em laboratório, simulando ambas as condições. A comparação entre os históricos dos dados industriais dos Concentradores I (operando sob circuito inverso) e do Concentrador II (operando sob circuito direto) mostrou um histórico consistente em que o circuito do Concentrador II apresenta menor consumo energético por tonelada de material gerado abaixo da malha de controle do circuito. Esses resultados foram diferentes daqueles obtidos a partir das amostragens realizadas no circuito industrial da Samarco, os quais indicaram melhor desempenho do circuito inverso. A diferença foi atribuída à etapa de classificação, cujo desempenho determina a alteração ou até mesmo anula os benefícios, conforme demonstram os resultados de simulação posteriores. Abstract in english This paper compares the performance associated with both direct and reverse ball mill closed circuit configurations. Survey campaigns were carried out in both Samarco Mineração industrial plants, i.e., Concentrator I and Concentrator II. The former is equipped with a reverse-configured ball mill clo [...] sed grinding circuit, while the latter is equipped with ball mills under a direct closed circuit. The study consisted of laboratory jar tests, as well as comparisons between historical data obtained for both industrial plants. Comparisons based on historical data indicated that Concentrator II, configured in a direct mode, exhibited a better performance than that of Concentrator I. Such a conclusion is in contrast with the results obtained from survey campaigns, which indicated a better performance for the reverse configuration. Such a difference was determined by the performance of the classification stage, carried out in cyclones, as demonstrated by simulations conducted on the basis of previously calibrated models.

  13. Preliminary study of sintering of metallic niobium processed for mechanical milling; Estudo preliminar da sinterizacao de niobio metalico processado por moagem de alta energia

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, H.M.; Vurobi Junior, S.; Cintho, O.M., E-mail: lenatamura@interponta.com.b [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil); Sandim, H.R.Z.; Leite, G.S. [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia

    2010-07-01

    In present study was preliminary study of mechanical milling influence on preparing of metallic niobium powder for sintering. Sample of metallic niobium in powder passing in sieve no. 635 mesh was processed by mechanical milling in SPEX mill for 8 hours using power grinding of 7:1 and a nitrogen atmosphere. The powder was annealed at different temperatures, 900 deg C, 1000 deg C, 1100 deg C and 1200 deg C for 1 hour in an atmosphere of hydrogen and argon to study their crystallization, which then were formed into blank for analysis of the curves compressibility. These samples were also subjected to x-ray diffraction in that their data were compared between the annealing temperatures. We also evaluate the compressibility curves of niobium samples with and without grinding these samples were subjected to x-ray diffraction and fluorescence. (author)

  14. Chemistry and structure of coals: Effects of grinding media on a subbituminous coal

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, E.L. Jr.

    1990-01-01

    Coal preparation techniques used to provide feedstocks for direct utilization in combustion facilities require extensive grinding. Separation of noxious elements (mineral matter, sulfur, nitrogen, etc.) is facilitated by grinding. Current and future needs for clean air require that more complete separation be carried out. Chemical cleaning processes can be combined and carried out simultaneously by incorporation of chemicals in the grinding media. This work has shown that the argillic mineral matter hydrolyzes in aqueous grinding media and the hydrolysis is markedly enhanced in alkaline media. Direct incorporation of carbon dioxide is accomplished in the alkaline media to form ketone and acid salt groups on the surface of subbituminous coal particles. Diffuse reflectance infrared spectroscopy has been shown to be an excellent aid in defining the chemical and physical changes induced in the grinding process. 8 refs., 12 figs.

  15. Effect of Cooling Environment on Grinding Performance of Nickel Based Superalloy Inconel 718

    Directory of Open Access Journals (Sweden)

    Raju S. Pawade

    2012-01-01

    Full Text Available The study presents the experimental investigation of surface grinding of superalloy Inconel 718. The grinding performance in terms of grinding force, surface roughness and surface topography were examined by conducting statistical experiments. The parameters that have been chosen as control factors are: table speed, infeed, grit size and the type of lubricant. An L27 orthogonal array experiments were conducted. The results show that the grit size and infeed are the most significant parameters on surface roughness Ra measured across the table feed direction. The interaction effect between lubricant and grit size is relatively important as compared to the individual effect of the latter variable. As far as the grinding forces are concerned, the grit size and table speed have largest contribution among the chosen parameters. SEM (Semester examination revealed the flaws such as abrasion marks, smeared layers and micro-particle deposits on the surfaces produced in grinding.

  16. 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.

  17. 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

  18. Vertical multi-plane grinding machine SAR60; Tatejiku tamen kensakuban SAR60

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-20

    This is a small and highly accurate machine of the vertical spindle multi-plane grinding machine SAR series. The purpose of the machine is to grind with ultra-accuracy inner/outer/end faces of ceramics, new materials, etc. The main specifications are as follows. Maximum grinding outer diameter: 600mm. Maximum processing height: 400mm. Grinding wheel spindle drive use motor: AC5.5/7.5kW. NC controller: FANUC 18i-T. The features are as follows. (1) The setting of a grinding head up/down and right/left cancels errors of accuracy such as thermal displacement by the scale feedback control. (2) The automatic exchange of grinder made the automatic operation from rough processing to finish processing possible. (3) The dressing of diamond wheel on the machine was made possible by rotary dresser. (translated by NEDO)

  19. Manufacturing Demonstration Facility: Roll-to-Roll Processing

    Energy Technology Data Exchange (ETDEWEB)

    Datskos, Panos G [ORNL; Joshi, Pooran C [ORNL; List III, Frederick Alyious [ORNL; Duty, Chad E [ORNL; Armstrong, Beth L [ORNL; Ivanov, Ilia N [ORNL; Jacobs, Christopher B [ORNL; Graham, David E [ORNL; Moon, Ji Won [ORNL

    2015-08-01

    This Manufacturing Demonstration Facility (MDF)e roll-to-roll processing effort described in this report provided an excellent opportunity to investigate a number of advanced manufacturing approaches to achieve a path for low cost devices and sensors. Critical to this effort is the ability to deposit thin films at low temperatures using nanomaterials derived from nanofermentation. The overarching goal of this project was to develop roll-to-roll manufacturing processes of thin film deposition on low-cost flexible substrates for electronics and sensor applications. This project utilized ORNL s unique Pulse Thermal Processing (PTP) technologies coupled with non-vacuum low temperature deposition techniques, ORNL s clean room facility, slot dye coating, drop casting, spin coating, screen printing and several other equipment including a Dimatix ink jet printer and a large-scale Kyocera ink jet printer. The roll-to-roll processing project had three main tasks: 1) develop and demonstrate zinc-Zn based opto-electronic sensors using low cost nanoparticulate structures manufactured in a related MDF Project using nanofermentation techniques, 2) evaluate the use of silver based conductive inks developed by project partner NovaCentrix for electronic device fabrication, and 3) demonstrate a suite of low cost printed sensors developed using non-vacuum deposition techniques which involved the integration of metal and semiconductor layers to establish a diverse sensor platform technology.

  20. Rolling Process Modeling Report: Finite-Element Prediction of Roll Separating Force and Rolling Defects

    Energy Technology Data Exchange (ETDEWEB)

    Soulami, Ayoub [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-04-23

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum (U-10Mo) alloy plate-type fuel for the U.S. high-performance research reactors. This work supports the Convert Program of the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) Global Threat Reduction Initiative. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll separating forces and rolling defects. Simulations were performed using a finite-element model developed using the commercial code LS-Dyna. Simulations of the hot rolling of U-10Mo coupons encapsulated in low-carbon steel have been conducted following two different schedules. Model predictions of the roll-separation force and roll-pack thicknesses at different stages of the rolling process were compared with experimental measurements. This report discusses various attributes of the rolled coupons revealed by the model (e.g., dog-boning and thickness non-uniformity).

  1. Rolling Resistance Measurement and Model Development

    DEFF Research Database (Denmark)

    Andersen, Lasse Grinderslev; Larsen, Jesper; Fraser, Elsje Sophia; Schmidt, Bjarne; Dyre, J. C.

    2015-01-01

    There is an increased focus worldwide on understanding and modeling rolling resistance because reducing the rolling resistance by just a few percent will lead to substantial energy savings. This paper reviews the state of the art of rolling resistance research, focusing on measuring techniques, surface and texture modeling, contact models, tire models, and macro-modeling of rolling resistance

  2. Deformation analysis of micro/nano indentation and diamond grinding on optical glasses

    Science.gov (United States)

    Zhao, Qingliang; Zhao, Lingling; Guo, Bing; Stephensin, David; Corbett, John

    2012-05-01

    The previous research of precision grinding optical glasses with electrolytic in process dressing (ELID) technology mainly concentrated on the action of ELID and machining parameters when grinding, which aim at generating very "smoothed" surfaces and reducing the subsurface damage. However, when grinding spectrosil 2000 and BK7 glass assisted with ELID technology, a deeply comparative study on material removal mechanism and the wheel wear behaviors have not been given yet. In this paper, the micro/nano indentation technique is initially applied for investigating the mechanical properties of optical glasses, whose results are then refereed to evaluate the machinability. In single grit diamond scratching on glasses, the scratching traces display four kinds of scratch characteristics according to different material removal modes. In normal grinding experiments, the result shows BK7 glass has a better machinability than that of spectrosil 2000, corresponding to what the micro/nano indentation vent revealed. Under the same grinding depth parameters, the smaller amplitude of acoustic emission (AE) raw signals, grinding force and grinding force ratio correspond to a better surface quality. While for these two kinds of glasses, with the increasing of grinding depth, the variation trends of the surface roughness, the force ratio, and the AE raw signals are contrary, which should be attributed to different material removal modes. Moreover, the SEM micrographs of used wheels surface indicate that diamond grains on the wheel surface after grinding BK7 glass are worn more severely than that of spectrosil 2000. The proposed research analyzes what happened in the grinding process with different material removal patterns, which can provide a basis for producing high-quality optical glasses and comprehensively evaluate the surface and subsurface integrity of optical glasses.

  3. 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.

  4. Effects of high energy grinding under different atmospheres on the solubility of lithium in copper an pure copper

    International Nuclear Information System (INIS)

    The mechanical alloying process (MA) has successfully obtained supersaturated solid solutions in a great many binary systems. Increased solubility of over 90% compared to the maximum in equilibrium for the solutes Ag and Co and increases greater than 50% for Cr and Fe have been reported after using MA for the production of copper-based alloys. This has led to the development of much research to determine the maximum solubilities in solid state that can be reached with this process and for different solutes. Lithium is one of the elements investigated. Unlike other metallic elements, lithium has had, comparatively speaking, a recent introduction in the area of investigation of structural materials. The reason is simple, none of lithium's properties had been fundamental in this field until a little more than three decades ago. Lithium is an element with exceptional chemical and physical properties but due to its high reactivity, obtaining it complicates the operating conditions under which it is processed. The formation of a copper-based alloy with lithium has major theoretical advantages particularly relative to reducing the density of the copper-based alloy. However, these elements have other physical and chemical properties that complicate this development when using conventional alloying production processes, particularly those involving a fusion stage, so the use of mechanical alloying as an alternative process has been proposed. Besides developing in solid state, MA has proven to be particularly efficient in obtaining solid solutions of elements that, under conditions of equilibrium, show very limited or even no solubility. This work has studied the effects of two control atmospheres on the high energy grinding of Cu and Li and pure copper, as well as the effect of milling time for both atmospheres. The milling for this study was carried out in a SPEX 8000D mill using a balls to powder ratio of 10:1, with steel containers and balls. The milling times varied from 3 to 30 hours and the control atmospheres used were argon and nitrogen. The microstructural changes of the powders as a function of the variables studied, were analyzed with scanning electron microscopy on a Philips XL-30 SFEG. The phases present in the samples were analyzed using X-ray diffraction on a Siemens 5000 diffractometer. The iron quantities in the samples after milling, were determined with atomic adsorption spectroscopy in a GBS 905 spectrometer and the oxygen contents were determined with infrared spectroscopy on a LECO TC-436 DR. Results show a marked effect of the control atmosphere on the microstructural characteristics and chemical composition of the copper and on the chemical composition in the case of the Cu-Li alloys (cw)

  5. Rolling Stitch Welder For Foil

    Science.gov (United States)

    Gilbert, Jeffery L.; Morgan, Gene E.

    1992-01-01

    Hand-operated rolling spotwelder stitch-welds foil faster and more consistently than single-spotwelding gun without damaging it. Internal spring reacts against roller frame, exerting force on welding wheel when rollers contact workpiece.

  6. 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...

  7. Adaptive Rolling Plans Are Good

    OpenAIRE

    Ma?kowiak, Piotr

    2009-01-01

    Here we prove the goodness property of adaptive rolling plans in a multisector optimal growth model under decreasing returns in deterministic environment. Goodness is achieved as a result of fast convergence (at an asymptotically geometric rate) of the rolling plan to balanced growth path. Further on, while searching for goodness, we give a new proof of strong concavity of an indirect utility function – this result is achieved just with help of some elementary matrix algebra an...

  8. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  9. [Reduction of dust during manual grinding of cast iron].

    Science.gov (United States)

    Gli?ski, Maciej

    2002-01-01

    The method for determining the emission of dust and the effectiveness of dust removal from machines and devices by local exhaust ventilation to the workplace air is presented. This method consists in determining concentrations of air pollution in the measuring duct through which it is sucked off from the chambers with tested devices. At the same time the volume of air flow rate is measured. A laser dust analyzer is used to measure dust concentrations in the air. Air is sampled with isokinetic sampling heads. It was shown that dust emission at different kinds of manual grinding of cast iron without ventilation was between 24 mg/min and 8131 mg/min, whereas with the use of local exhaust ventilation it decreased below 35 mg/min. The efficiency of the exhaust elements was over 95% at optimum use of local ventilation. PMID:12051159

  10. 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 ?nish has become an important parameter in the semiconductor, optical, electrical and mechanical industries. The materials used in these industries are classi?ed as dif?cult 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 ?nishing 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.

  11. Direct measures of mechanical energy for knife mill size reduction

    Energy Technology Data Exchange (ETDEWEB)

    Bitra, V.S.P. [University of Tennessee; Womac, A.R. [University of Tennessee; Igathinathane, C. [Mississippi State University (MSU); Miu, P.I [University of Tennessee; Yang, Y.T. [University of Tennessee; Smith, D.R. [University of Tennessee; Chevanan, Nehru [University of Tennessee; Sokhansanj, Shahabaddine [ORNL

    2009-08-01

    Lengthy straw/stalk of biomass may not be directly fed into grinders such as hammer mills and disc refiners. Hence, biomass needs to be preprocessed using coarse grinders like a knife mill to allow for efficient feeding in refiner mills without bridging and choking. Size reduction mechanical energy was directly measured for switchgrass (Panicum virgatum L.), wheat straw (Triticum aestivum L.), and corn stover (Zea mays L.) in an instrumented knife mill. Direct power inputs were determined for different knife mill screen openings from 12.7 to 50.8 mm, rotor speeds between 250 and 500 rpm, and mass feed rates from 1 to 11 kg/min. Overall accuracy of power measurement was calculated to be 0.003 kW. Total specific energy (kWh/Mg) was defined as size reduction energy to operate mill with biomass. Effective specific energy was defined as the energy that can be assumed to reach the biomass. The difference is parasitic or no-load energy of mill. Total specific energy for switchgrass, wheat straw, and corn stover chopping increased with knife mill speed, whereas, effective specific energy decreased marginally for switchgrass and increased for wheat straw and corn stover. Total and effective specific energy decreased with an increase in screen size for all the crops studied. Total specific energy decreased with increase in mass feed rate, but effective specific energy increased for switchgrass and wheat straw, and decreased for corn stover at increased feed rate. For knife mill screen size of 25.4 mm and optimum speed of 250 rpm, optimum feed rates were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively, and the corresponding total specific energies were 7.57, 10.53, and 8.87 kWh/Mg and effective specific energies were 1.27, 1.50, and 0.24 kWh/Mg for switchgrass, wheat straw, and corn stover, respectively. Energy utilization ratios were calculated as 16.8%, 14.3%, and 2.8% for switchgrass, wheat straw, and corn stover, respectively. These data will be useful for preparing the feed material for subsequent fine grinding operations and designing new mills.

  12. FM Interviews: Stephanie Mills

    OpenAIRE

    Valauskas, Edward

    2002-01-01

    Stephanie Mills is an author, editor, lecturer and ecological activist who has concerned herself with the fate of the earth and humanity since 1969, when her commencement address at Mills College in Oakland, Calif., drew the attention of a nation. Her speech, which the New York Times called "perhaps the most anguished statement" of the year's crop of valedictory speeches, predicted a bleak future. According to Mills, humanity was destined for suicide, the result of overpopulation and overuse ...

  13. Modelling of fracture wear in vitrified cBN grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2007-09-01

    Full Text Available Purpose: The paper describes modelling of fracture wear in vitrified cBN grinding wheels.Design/methodology/approach: The approach used in the paper is based on using finite elements to model fracture wear processes in vitrified cBN grinding wheels. The approach used models fracture wear processes and ignores abrasive wear of the abrasive grains.Findings: The findings show that during grinding the grain is subjected to forces that create fracture initiation zones in the sharp abrasive grains where tensile and compressive stresses dominate in certain parts of the abrasive grains.Research limitations/implications: The findings show that further research is required that prevents the formation of crack initiation zones and considers the effects of wear flats on the magnitude of stresses in the abrasive grains.Practical implications: The results imply that abrasive fracture wear is the dominant wear mechanism when grinding with sharp vitrified cBN grinding wheels.Originality/value: The originality of this paper is reflected in the fact that this is the first time that fracture wear has been modelled in sharp vitrified cBN grinding wheels. The results presented in this paper will illuminate the need for accurate modelling of the wear of vitrified superabrasive grinding wheels.

  14. Novel grinding stone used for polishing 3D plastic replica with rapid prototyping technology

    Science.gov (United States)

    Feng, Wang; Niikura, Yoshihiro; Sato, Toshio; Kawashima, Norimichi

    2006-01-01

    Rapid prototyping (RP) apparatus accepts a specific format translated from CAD data (patient's CT) and "slices" it into two-dimensional cross sections for laser photo curing. Surgeon can conduct safer surgery by reappearing on an actual model using 3D plastic replica in the preoperative. Polishing has to be used to eliminate the marks after removal of supports and the build layer pitches. Complicated and narrow areas of the 3D replica are difficult to be polished with the conventional grinding stone. This study proposes a novel grinding stone and introduces its producing process and characteristics. The novel grinding stone has many advantages as follows; (1) Preparation is possible of grinding stone that follows the complicated shape. (2) Grinding stone with uniformly dispersed abrasive grains can be prepared using magnetic particles and magnetic field. (3) Reshaping of grinding stone by heating is possible since the binder is made of a thermoplastic resin. (4) Every process can easily be carried out. We could polish to eliminate the marks after removal of supports and the build layer pitches on 3D plastic replica surface with the grinding stone.

  15. Controlled wear of vitri?ed 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. Vitri?ed 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 ?nish 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 vitri?cation heat treatment on the development of strength between abrasive grains and bonding bridges, and the nature of fracture and wear in vitri?ed grinding wheels that are used for precision grinding applications.

  16. Advances and patents about grinding equipments with nano-particle jet minimum quantity lubrication.

    Science.gov (United States)

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

    2014-01-01

    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 controllable nano-fluids jet MQL grinding system based on electrostatic atomization. Using the principle of electrostatics, it can achieve the control of droplet transfer by charging the sprayed droplets. This system can improve the uniformity of the droplet spectrum, liquid deposition efficiency and effective utilization of liquid. It can also effectively control the movement patterns of the droplets, thereby reducing the pollution of the environment and providing better health protection for workers. Although researchers accomplished profound and systematic studies on MQL, especially on nano-particles jet MQL. It can solve the shortage of MQL in cooling performance, greatly improve the working environment, save energy and reduce costs to achieve a low-carbon manufacturing. The unique lubricating performance and tribological property of solid nano-particles form nano-particle shearing films at the grinding wheel/workpiece interface, which can enhance the lubricating performance of MQL grinding. Existing studies on MQL grinding equipments, however, cannot meet the needs of the technological development. Therefore, our research provided a general introduction of the latest patients and research progress of nanoparticles jet MQL grinding equipments presented by the research team from Qingdao Technological University. PMID:25336175

  17. The effect of roll gap geometry on microstructure in cold-rolled aluminum

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bay, B.; Winther, G.; Juul Jensen, D.

    2004-01-01

    Microstructure and texture are analyzed through the thickness of two aluminum plates cold-rolled 40% with different roll gap geometries. It is found that both texture and microstructure are strongly affected by the rolling geometry. After rolling with intermediate-size draughts a rolling-type texture is developed throughout the plate thickness. In this case, grains are subdivided by extended planar dislocation boundaries preferentially aligned at an angle of 40 +/- 15degrees to the rolling direc...

  18. Diseño y Evaluación Energética de dos Circuitos de Molienda y Clasificación para un Clinker de Cemento a Escala Piloto / Design and Energy Evaluation of two Grinding and Classifier Circuits of a Pilot Scale Cement Clinker

    Scientific Electronic Library Online (English)

    Adriana M, Osorio; Juan M, Marín; Gloria, Restrepo.

    Full Text Available Se presentan los resultados del diseño y evaluación de dos sistemas de molienda en circuito cerrado, para un clasificador tipo ciclón neumático y uno tipo harnero vibratorio. Se comparan las eficiencias energéticas bajo similares condiciones de granulometrías a la entrada del molino, conservando el [...] mismo tamaño de corte en el clasificador. El material se caracterizó mediante: fluorescencia de rayos X, area superficial por el método Brunauer-Emmet-Teller y análisis granulométrico por tamizado. Los resultados indican que la velocidad de giro del molino no tiene significancia estadística sobre la eficiencia mecánica de molienda. A partir de un análisis de superficies de respuestas se determinó que el ciclón favorece la eficiencia (valor óptimo 30%) comparado con el harnero (valor óptimo 18%). Los modelos encontrados para la determinación de la eficiencia mecánica del sistema molino-ciclón y molino-harnero, muestran correlaciones del 85 y 83 % respectivamente. Abstract in english The design and experimental evaluation of two grinding systems in closed circuit which use two types of classifiers, a pneumatic cyclone and a sieve vibratory, were carried out. The energetic efficiencies under similar conditions in material particle sizes at the mill entrance and keeping the same c [...] lassifier were compared. The material was characterized by: X-ray fluorescence (XRF), surface area by the method Brunauer-Emmet-Teller and granulometry analysis by sieving. Results show that the mill speed does not have statistical significance over the grinding mechanical efficiency and using a response surface analysis was determined that the cyclone favors the milling (optimum value 30%) against the sieve vibratory type (optimum 18%). Models found for mechanical efficiency determination of the systems mill-cyclone and mill-sieve vibratory, show correlations of 85 % and 83%, respectively.

  19. Diseño y Evaluación Energética de dos Circuitos de Molienda y Clasificación para un Clinker de Cemento a Escala Piloto Design and Energy Evaluation of two Grinding and Classifier Circuits of a Pilot Scale Cement Clinker

    Directory of Open Access Journals (Sweden)

    Adriana M Osorio

    2013-01-01

    Full Text Available Se presentan los resultados del diseño y evaluación de dos sistemas de molienda en circuito cerrado, para un clasificador tipo ciclón neumático y uno tipo harnero vibratorio. Se comparan las eficiencias energéticas bajo similares condiciones de granulometrías a la entrada del molino, conservando el mismo tamaño de corte en el clasificador. El material se caracterizó mediante: fluorescencia de rayos X, area superficial por el método Brunauer-Emmet-Teller y análisis granulométrico por tamizado. Los resultados indican que la velocidad de giro del molino no tiene significancia estadística sobre la eficiencia mecánica de molienda. A partir de un análisis de superficies de respuestas se determinó que el ciclón favorece la eficiencia (valor óptimo 30% comparado con el harnero (valor óptimo 18%. Los modelos encontrados para la determinación de la eficiencia mecánica del sistema molino-ciclón y molino-harnero, muestran correlaciones del 85 y 83 % respectivamente.The design and experimental evaluation of two grinding systems in closed circuit which use two types of classifiers, a pneumatic cyclone and a sieve vibratory, were carried out. The energetic efficiencies under similar conditions in material particle sizes at the mill entrance and keeping the same classifier were compared. The material was characterized by: X-ray fluorescence (XRF, surface area by the method Brunauer-Emmet-Teller and granulometry analysis by sieving. Results show that the mill speed does not have statistical significance over the grinding mechanical efficiency and using a response surface analysis was determined that the cyclone favors the milling (optimum value 30% against the sieve vibratory type (optimum 18%. Models found for mechanical efficiency determination of the systems mill-cyclone and mill-sieve vibratory, show correlations of 85 % and 83%, respectively.

  20. Effect of Grinding Induced Damage on Bending Strength of RBSiC

    Directory of Open Access Journals (Sweden)

    YAO Wang,ZHANG Yu-Min,HAN Jie-Cai,ZHA Yan-Feng£¬ZHOU Yu-Feng,HAN Yuan-Yuan,QU Wei

    2009-03-01

    Full Text Available The effect of surface residual stress and crack on bending strength of reaction bonded silicon carbide (RBSiC after grinding was investigated. The residual stress of the ground surfaces were determined using X-ray diffraction.The sizes of strength controlling cracks were assessed using fracture mechanics approach. The investigations show that mechanical load, which has relation with grinding direction, phays a dominateve role in the grinding processes. and the measured residual stresses have a direction dependency. With increase of down feed from 0.9¦?/s to 1.35¦?/s, the bending strength is reasonably correlated with the surface residual stress and crack size.

  1. 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.

  2. Relationships between gluten content and grinding properties of wheat (a short communication

    Directory of Open Access Journals (Sweden)

    Devaux M.F.

    1999-09-01

    Full Text Available In 14 wheat samples from mixed varieties, the wet gluten content was significantly correlated with grinding energy and particle size of flours. The particle size distributions were bimodal with a main mode between 570 and 690 mm and a second mode between 28 and 34 mm. The main mode was higher for samples with a high gluten content. Conversely, samples with a low gluten content exhibited a higher second mode. A grinding ability index calculated as the quotient of specific grinding energy to specific surface was highly correlated with the gluten content (r=0.90.

  3. Relationships between gluten content and grinding properties of wheat (a short communication)

    OpenAIRE

    Devaux M.F.; Laskowski J.; Le Deschault de Monredon F.

    1999-01-01

    In 14 wheat samples from mixed varieties, the wet gluten content was significantly correlated with grinding energy and particle size of flours. The particle size distributions were bimodal with a main mode between 570 and 690 mm and a second mode between 28 and 34 mm. The main mode was higher for samples with a high gluten content. Conversely, samples with a low gluten content exhibited a higher second mode. A grinding ability index calculated as the quotient of specific grinding energy to sp...

  4. Effect of Superfine Grinding on Antidiabetic Activity of Bitter Melon Powder

    OpenAIRE

    Zhiyu Xiong; Yi Zhang; Yun Wang; Xinghua Zhou; Qin Guo; Xiwen Qian; Fengjie Cui; Ying Dong; Ying Zhu

    2012-01-01

    The antidiabetic activities of bitter melon powders produced with lyophilization/superfine grinding and hot air drying/normal grinding were investigated in vivo for selecting a suitable bitter melon processing procedure. After a five-week treatment, bitter melon lyophilized superfine grinding powder (BLSP) had a higher antidiabetic activity with reducing fasting blood glucose levels from 21.40 to 12.54 mmol/L, the serum insulin levels from 40.93 to 30.74 mIU/L, and restoring activities of SOD...

  5. Synthesis of vanadium-modified rutile TiO2 nanoparticle by reactive grinding method and its photocatalytic activity under solar light at room temperature

    International Nuclear Information System (INIS)

    Rutile TiO2 was synthesized by sol–gel method. Vanadium-doped rutile TiO2 nanoparticle was obtained by reactive grinding method. The photocatalytic activity was evaluated by the degradation of methylene blue (MB) under solar light at room temperature. The results show that after 4 h of milling the particle size of rutile decreased from 130 to 14 nm and the Brunauer–Emmet–Teller (BET) specific surface area increased from 7.18 to 15.12 m2 g?1. The vanadium doping promoted the particle growth and the particle size of vanadium-modified rutile TiO2 obtained by 4 h of milling is about 22 nm, but the BET specific surface area increased from 15.12 m2 g?1 for TiO2 to 20.8 m2 g?1 for vanadium-doped TiO2 under the same conditions. The 5% vanadium-doped rutile possessed better absorption ability of solar light; the calculated band gap energy value is 2.7 eV. The degradation rate of MB on vanadium-doped rutile TiO2 was higher than that of pure rutile obtained after the same time of milling. (paper)

  6. Synthesis of vanadium-modified rutile TiO2 nanoparticle by reactive grinding method and its photocatalytic activity under solar light at room temperature

    Science.gov (United States)

    Nguyet Tran, Thi Minh; Hoang Yen Quach, Thi; Tran, Que Chi; Nguyen, Thi Toan; Chien Nguyen, Van; Do, Hung Manh; Thanh Tran, Dang; Nhung Nguyen, Hong; Tuyen Vu, Phi; Khuong Le, Dang

    2013-09-01

    Rutile TiO2 was synthesized by sol-gel method. Vanadium-doped rutile TiO2 nanoparticle was obtained by reactive grinding method. The photocatalytic activity was evaluated by the degradation of methylene blue (MB) under solar light at room temperature. The results show that after 4 h of milling the particle size of rutile decreased from 130 to 14 nm and the Brunauer-Emmet-Teller (BET) specific surface area increased from 7.18 to 15.12 m2 g-1. The vanadium doping promoted the particle growth and the particle size of vanadium-modified rutile TiO2 obtained by 4 h of milling is about 22 nm, but the BET specific surface area increased from 15.12 m2 g-1 for TiO2 to 20.8 m2 g-1 for vanadium-doped TiO2 under the same conditions. The 5% vanadium-doped rutile possessed better absorption ability of solar light; the calculated band gap energy value is 2.7 eV. The degradation rate of MB on vanadium-doped rutile TiO2 was higher than that of pure rutile obtained after the same time of milling.

  7. Online monitoring and control of particle size in the grinding process using least square support vector regression and resilient back propagation neural network.

    Science.gov (United States)

    Pani, Ajaya Kumar; Mohanta, Hare Krishna

    2015-05-01

    Particle size soft sensing in cement mills will be largely helpful in maintaining desired cement fineness or Blaine. Despite the growing use of vertical roller mills (VRM) for clinker grinding, very few research work is available on VRM modeling. This article reports the design of three types of feed forward neural network models and least square support vector regression (LS-SVR) model of a VRM for online monitoring of cement fineness based on mill data collected from a cement plant. In the data pre-processing step, a comparative study of the various outlier detection algorithms has been performed. Subsequently, for model development, the advantage of algorithm based data splitting over random selection is presented. The training data set obtained by use of Kennard-Stone maximal intra distance criterion (CADEX algorithm) was used for development of LS-SVR, back propagation neural network, radial basis function neural network and generalized regression neural network models. Simulation results show that resilient back propagation model performs better than RBF network, regression network and LS-SVR model. Model implementation has been done in SIMULINK platform showing the online detection of abnormal data and real time estimation of cement Blaine from the knowledge of the input variables. Finally, closed loop study shows how the model can be effectively utilized for maintaining cement fineness at desired value. PMID:25528293

  8. Preparation of magnesium ferrite nanoparticles by ultrasonic wave-assisted aqueous solution ball milling.

    Science.gov (United States)

    Chen, Ding; Li, Dian-yi; Zhang, Ying-zhe; Kang, Zhi-tao

    2013-11-01

    Magnesium ferrite, MgFe2O4 nanoparticles with high saturation magnetization were successfully synthesized using ultrasonic wave-assisted ball milling. In this study, the raw materials were 4MgCO3·Mg(OH)2·5H2O and Fe2O3 powders and the grinding media was stainless steel ball. The average particle diameter of the product MgFe2O4 powders was 20 nm and the saturation magnetization of them reached 54.8 emu/g. The different results of aqueous solution ball milling with and without ultrasonic wave revealed that it was the coupling effect of ultrasonic wave and mechanical force that played an important role during the synthesis of MgFe2O4. In addition, the effect of the frequency of the ultrasonic wave on the ball milling process was investigated. PMID:23622867

  9. Improving Energy Efficiency Via Optimized Charge Motion and Slurry Flow in Plant Scale Sag Mills

    Energy Technology Data Exchange (ETDEWEB)

    Raj K. Rajamani

    2006-07-21

    A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Outokumpu Technology, Kennecott Utah Copper Corporation, and Process Engineering Resources Inc. At Cortez Gold Operations the shell and pulp lifters of the semiautogenous grinding mill was redesigned. The redesigned shell lifter has been in operation for over three years and the redesigned pulp lifter has been in operation for over nine months now. This report summarizes the dramatic reductions in energy consumption. Even though the energy reductions are very large, it is safe to say that a 20% minimum reduction would be achieved in any future installations of this technology.

  10. High-precision thickness setting models for titanium alloy plate cold rolling without tension

    Science.gov (United States)

    Wang, Xiaochen; Yang, Quan; He, Fei; Sun, Youzhao; Xiao, Huifang

    2015-03-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  11. Ball milling pretreatment of corn stover for enhancing the efficiency of enzymatic hydrolysis.

    Science.gov (United States)

    Lin, Zengxiang; Huang, He; Zhang, Hongman; Zhang, Lin; Yan, Lishi; Chen, Jingwen

    2010-11-01

    Ethanol can be produced from lignocellulosic biomass with the usage of ball milling pretreatment followed by enzymatic hydrolysis and fermentation. The sugar yields from lignocellulosic feed stocks are critical parameters for ethanol production process. The research results from this paper indicated that the yields of glucose and xylose were improved by adding any of the following dilute chemical reagents: H(2)SO(4), HCl, HNO(3), CH(3)COOH, HCOOH, H(3)PO(4), and NaOH, KOH, Ca(OH)(2), NH(3)·H(2)O in the ball milling pretreatment of corn stover. The optimal enzymatic hydrolysis efficiencies were obtained under the conditions of ball milling in the alkali medium that was due to delignification. The data also demonstrated that ball milling pretreatment was a robust process. From the microscope image of ball milling-pretreated corn stover, it could be observed that the particle size of material was decreased and the fiber structure was more loosely organized. Meanwhile, the results indicate that the treatment effect of wet milling is better than that of dry milling. The optimum parameters for the milling process were ball speed of 350 r/min, solid/liquid ratio of 1:10, raw material particle size with 0.5 mm, and number of balls of 20 (steel ball, ??=?10 mm), grinding for 30 min. In comparison with water milling process, alkaline milling treatment could increase the enzymatic hydrolysis efficiency of corn stover by 110%; and through the digestion process with the combination of xylanase and cellulase mixture, the hydrolysis efficiency could increase by 160%. PMID:20593309

  12. Roll casting of 5182 aluminium alloy

    OpenAIRE

    Haga, T; M. Mtsuo; D. Kunigo; Hatanaka, Y; R. Nakamuta; Watari, H; S. Kumai

    2009-01-01

    Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material.Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed....

  13. Hot rolling of thick uranium molybdenum alloys

    Energy Technology Data Exchange (ETDEWEB)

    DeMint, Amy L.; Gooch, Jack G.

    2015-11-17

    Disclosed herein are processes for hot rolling billets of uranium that have been alloyed with about ten weight percent molybdenum to produce cold-rollable sheets that are about one hundred mils thick. In certain embodiments, the billets have a thickness of about 7/8 inch or greater. Disclosed processes typically involve a rolling schedule that includes a light rolling pass and at least one medium rolling pass. Processes may also include reheating the rolling stock and using one or more heavy rolling passes, and may include an annealing step.

  14. Bay Mills' Bold Approach

    Science.gov (United States)

    Freedman, Eric

    2011-01-01

    It's a long, long way from Bay Mills Community College, near the shores of frigid Lake Superior, to Detroit. But distance, time and demographics aside, the school and the city are united by Bay Mills' status as the nation's only tribally controlled college that authorizes quasi-public schools, known officially as public school academies. And it's…

  15. Changes in pH and ion composition in liquid media caused by mineral grinding: its dependency to mineral species

    Science.gov (United States)

    Saito, T.; Tanaka, H.

    2009-04-01

    In natural fault zone, rocks and minerals were fractured by seismic slip, resulting in increase in surface area of minerals. Increasing in surface area cause minerals to be chemically activated. Therefore, fluid-rock interaction is enhanced in fluid-rich area such as subduction zone and shallow intra-plate fault zone. Fluid-rock interaction would change the physical and chemical properties of the fault zone materials. Therefore, fluid-rock reaction is important for understanding feedback relationship during earthquake cycle. However, the fundamental chemical processes of fluid-rock interaction caused by fracturing are still poorly understood. In natural fault zones, fault gouges are found as one of the pulverized rock. Fault gouges is also considered as a product of chemical reactions between rocks and surrounding groundwater. However, these chemical reactions are not completely understood. In this study, we concentrated on changes in fluid media by rock fracturing with water, especially changes in pH and dissolved chemical composition. The questions concerning changes in fluid media are addressed in this study: (1) what type chemical process is dominant? (2) To what extent is fluid-rock interaction depend on mineral species. To answer these questions, we conducted grinding experiment, which analogous to pulverization in natural fault. We performed grinding experiment using ball mill to investigate fluid-mineral interaction accompanied by mineral fracturing. Starting materials are silicate minerals (quartz, plagioclase, alkali feldspar, biotite, muscovite, and mixture of quartz and other minerals) as solid media, and pure water as fluid media. In regard to the mixture samples of quartz and other minerals, several mixing ration was used. We measure pH and chemical composition in water after grinding experiment. Results of experiment showed that pH changes in fluid media and chemical composition. Result of quartz experiment showed pH decrease. Result of plagioclase, alkali feldspar, biotite, muscovite other minerals, which contain metal ion showed increase in pH. These results about pH were corresponding to previous work (Saruwatari et al., 2003, 2004). Results of plagioclase, alkali feldspar, biotite, muscovite showed increase in ion concentration. Results of mixture of quartz and minerals that contain metal ion showed the value between result of quartz and that of other minerals. These experimental results demonstrate that the mixing ratio of quartz and other minerals affect pH and ion composition in fluid media after grinding. The pH value may strongly affects chemical processes such as precipitation and dissolution of minerals in fault zone after seismic slip occurred. According to the experimental results discussed above, mineral composition of rocks in fault zone may be crucial for chemical process after seismic slip (especially, immediately after seismic slip). However, the timescale in these chemical processes is still unknown. We will discuss in presentation that application of these experimental results to natural brittle fault zone.

  16. Grinding of AISI 4340 steel with interrupted cutting by aluminum oxide grinding wheel / Retificação do aço AISI 4340 usando corte interrompido com rebolo convencional

    Scientific Electronic Library Online (English)

    Hamilton Jose de, Mello; Diego Rafael de, Mello; Eduardo Carlos, Bianchi; Paulo Roberto de, Aguiar; Doriana M., D' Addona.

    2015-06-01

    Full Text Available Resumo No processo de retificação, muito já se avançou com o desenvolvimento de métodos de dressagem de rebolos, de lubrirefrigeração e de outros mais. Todavia, todos esses progressos foram conseguidos apenas no que diz respeito ao corte contínuo, ou seja, o perfil da peça retificada não sofre desco [...] ntinuidade alguma. Nesse sentido, torna-se necessário o estudo do processo de retificação por corte intermitente (peça com ranhuras – corte descontínuo), pois pouco ou, mesmo, nenhum conhecimento e/ou estudo foi desenvolvido com esse enfoque, visto que não é encontrado material algum na literatura formal, salvo aqueles em que o rebolo é o detentor das ranhuras. Na retificação, o calor gerado na zona de corte é extremamente elevado. Dessa forma, o uso de fluidos de corte é indispensável para que seja possível refrigerar, tanto a peça, quanto o rebolo e propiciar melhorias na operação de corte, sendo o mais comum a utilização de fluido em abundância, tendo em vista que os agentes de arrefecimento e lubrificação são capazes de proporcionar uma retificação mais eficiente. Os ensaios foram realizados com um rebolo convencional de óxido de alúmínio, retificando corpos-de-prova confeccionados com aço ABNT 4340 temperado e revenido com 2, 6 e 12 ranhuras. A operação cilíndrica utilizada foi de mergulho, ou seja, o rebolo avança sobre a peça em movimento de rotação. Esse avanço é realizado com três velocidades distintas. Dos resultados obtidos, pode-se observar que a rugosidade tendeu a aumentar, para CP's com mesmo número de ranhuras, conforme foi aumentada a velocidade de mergulho. Os erros de circularidade, assim como a rugosidade, também tenderam a aumentar com o aumento da velocidade de mergulho, para CP's com mesmo número de ranhuras. O desgaste do rebolo tendeu a aumentar conforme aumentados a velocidade de mergulho e o número de ranhuras. A potência consumida pela retificadora foi inversamente proporcional ao número de ranhuras. A microdureza subsuperficial não provocou alteração significativa. E as micrografias revelaram que a usinagem foi satisfatória, pois não houve danos significativos à superficie usinada. Abstract in english Abstract There has been a great advance in the grinding process by the development of dressing, lubri-refrigeration and other methods. Nevertheless, all of these advances were gained only for continuous cutting; in other words, the ground workpiece profile remains unchanged. Hence, it becomes necess [...] ary to study grinding process using intermittent cutting (grooved workpiece – discontinuous cutting), as little or no knowledge and studies have been developed for this purpose, since there is nothing found in formal literature, except for grooved grinding wheels. During the grinding process, heat generated in the cutting zone is extremely high. Therefore, plenty of cutting fluids are essential to cool not only the workpiece but also the grinding wheel, improving the grinding process. In this paper, grinding trials were performed using a conventional aluminum oxide grinding wheel, testing samples made of AISI 4340 steel quenched and tempered with 2, 6, and 12 grooves. The cylindrical plunge grinding was performed by rotating the workpiece on the grinding wheel. This plunge movement was made at three different speeds. From the obtained results, it can be observed that roughness tended to increase for testing sample with the same number of grooves, as rotation speed increased. Roundness error also tended to increase as the speed rotation process got higher for testing the sample with the same number of grooves. Grinding wheel wear enhanced as rotation speed and number of grooves increased. Power consumed by the grinding machine was inversely proportional to the number of grooves. Subsuperficial microhardness had no significant change. Micrographs reveal an optimal machining operation as there was no significant damage on the machined surface.

  17. Robots grind rotor blades for wind power systems; Roboter schleifen Rotorblaetter fuer Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Drenkelfort, Gunnar [GDC Consulting GmbH, Guetersloh (Germany)

    2009-11-30

    An integrated concept for automatic manufacturing of wind power systems is presented for the first time. Automatic grinding of rotor blades by robots is a key element, which saves up to 70 percent of the production cost. (orig.)

  18. Relationships between subsurface damage depth and surface roughness of grinded glass optics

    Science.gov (United States)

    Blaineau, P.; Laheurte, R.; Darnis, P.; Darbois, N.; Cahuc, O.; Néauport, J.

    2013-09-01

    Relationships between subsurface damage (SSD) depth and peak to valley surface roughness (Rt) have been widely studied and present a major interest for an easy assessment of the SSD depth. We seek the relation between SSD depth and other surface roughness parameters using the Abbott-Firestone curve on a large campaign of grinding tests (with different abrasive grain size, grinding speed and grinding mode). The results reveal that the Abbott-Firestone parameter Mr2, which can be linked to the volume fraction of valley in the roughness profile, is more accurate than Rt for an assessment of the SSD depth and that the relationship between Mr2 and the SSD depth varies when changing the grinding mode.

  19. Ultra-precision grinding of grazing incidence X-ray mirrors by on-machine measurement

    International Nuclear Information System (INIS)

    This paper deals with a machining method for making a large non-axisymmetric aspheric surface with a high accuracy. An electric micrometer has been set near a grinding head on 5-axis control ultra-precision grinding machine for measuring the shape error of ground surface in conformity with the machine movement due to the cutter location data. A series of the measured shape errors corrects the former cutter location data automatically and the next grinding operation will be performed by the new cutter location data. A large CVD-SiC sample 110 by 510 mm has been ground into a toroidal surface of 0.75 ? m in shape accuracy by the fifth grinding operation with the fourth correction of cutter location data. The machine has been also installed in a constant temperature room of ±0.5K in variation. (author)

  20. Electrochemical interactions between mineral and grinding media and their effects on flotation and media wear

    Energy Technology Data Exchange (ETDEWEB)

    Pozzo, R.L.

    1987-01-01

    This report describes the electrochemical nature of mineral grinding media interactions in the wet grinding of one-and two-sulfide mineral ores with regard to the corrosive wear of the media and the flotation behavior of the minerals. Two iron sulfides (pyrite and pyrrhotite) and three types of steels (mild steel, high carbon forged steel, and austenitic stainless steel) were used to represent the sulfide minerals and the grinding media, respectively. Electrochemical measurements (rest and combination potentials, galvanic currents, and polarization behaviors) under abrasive and nonabrasive conditions were correlated with data from marked ball wear tests, Hallimond tube flotation tests, and with scanning electron photomicrographs and energy dispersive X-ray spectra. Corrosion currents obtained by superposition of polarization curves of sulfide mineral grinding media systems were in good agreement with corrosion currents estimated from ball wear data.

  1. Effects of mechanical grinding and low temperature annealing on crystal structure of Er5Si4

    International Nuclear Information System (INIS)

    Highlights: ? Impurity phases exist in orthorhombic Er5Si4:monoclinic 5:4, 1:1 and 5:3. ? Mechanical grinding induces transition from orthorhombic 5:4 to monoclinic 5:4. ? Low temperature annealing reverses the monoclinic 5:4 to orthorhombic 5:4. -- Abstract: The effect of mechanical grinding and subsequent low temperature annealing on the orthorhombic to monoclinic structural transition in the Er5Si4 compound was studied by X-ray powder diffraction using both a conventional laboratory Cu K?1 radiation and a high-energy synchrotron source. A reversible phase transition from the orthorhombic to monoclinic structure occurs as a result of mechanical grinding. Low temperature annealing reverses the transformation and converts the formed monoclinic phase back to the orthorhombic, evidently by relieving residual stress introduced during the grinding

  2. Compressible sleeve provides automatic centering for grinding or turning of cylinders

    Science.gov (United States)

    Rohrer, J. A.

    1968-01-01

    Elastomeric sleeve supported on a threaded mandrel automatically centers cylindrical castings for grinding or turning. By expanding the diameter of the sleeve with pressure against the ends, the casting becomes rigidly supported and the surfacing operation can be completed.

  3. Design and fundamental understanding of Minimum Quantity Lubrication (MQL) assisted grinding using advanced nanolubricants

    Science.gov (United States)

    Kalita, Parash

    Abrasive grinding is widely used across manufacturing industry for finishing parts and components requiring smooth superficial textures and precise dimensional tolerances and accuracy. Unlike any other machining operations, the complex thermo-mechanical processes during grinding produce excessive friction-induced energy consumption, heat, and intense contact seizures. Lubrication and cooling from grinding fluids is crucial in minimizing the deleterious effects of friction and heat to maximize the output part quality and process efficiency. The conventional flood grinding approach of an uneconomical application of large quantities of chemically active fluids has been found ineffective to provide sufficient lubrication and produces waste streams and pollutants that are hazardous to human health and environment. Application of Minimum Quantity Lubrication (MQL) that cuts the volumetric fluid consumption by 3-4 orders of magnitude have been extensively researched in grinding as a high-productivity and environmentally-sustainable alternative to the conventional flood method. However, the lubrication performance and productivity of MQL technique with current fluids has been critically challenged by the extreme thermo-mechanical conditions of abrasive grinding. In this research, an MQL system based on advanced nanolubricants has been proposed to address the current thermo-mechanical challenges of MQL grinding and improve its productivity. The nanolubricants were composed of inorganic Molybdenum Disulphide nanoparticles (? 200 nm) intercalated with organic macromolecules of EP/AW property, dispersed in straight (base) oils---mineral-based paraffin and vegetable-based soybean oil. After feasibility investigations into the grindability of cast iron using MQL with nanolubricants, this research focused on the fundamental understanding of tribological behavior and lubricating mechanisms of nanolubricants as a method to improve the productivity of MQL-assisted surface grinding of ductile iron and alloy steel. An extensive investigation on MQL-assisted grinding using vitrified aluminum oxide wheel under varied infeed and lubrication condition was carried out with the scope of documenting the process efficiency and lubrication mechanisms of the nanolubricants. Experimental results showed that MQL grinding with nanolubricants minimized the non-productive outputs of the grinding process by reducing frictional losses at the abrasive grain-workpiece interfaces, energy consumption, wheel wear, grinding zone temperatures, and friction-induced heat generation. Use of nanolubricants in MQL yielded superior productivity by producing surface roughness as low as 0.35 ?m and grinding efficiencies that were four times higher as compared to those obtained from flood grinding. Repeatable formation of tribochemical films of antifriction, antiwear, and extreme pressure chemical species in between the contact asperities of abrasive crystals and work material was identified with nanolubricants. The tribological behavior was characterized by this synergistic effect of the antiwear, antifriction, and load carrying chemical species that endured grain-workpiece seizures and reduced adhesion friction between the contact surfaces. Delivery of organic coated Molybdenum Disulphide nanoparticles by anchoring on the natural porosity of the abrasive wheel and eventually, sliding-induced interfacial deformation into tribolayers and alignment at the grinding zone were established as the lubrication mechanisms of the nanolubricants. These mechanisms were further validated from tribological evaluations of lubricated cubic boron nitride (cBN) superabrasives-1045 steel sliding pairs on a reciprocating tribotest rig resembling the tool-lubricant-workpiece interactions of MQL-assisted grinding.

  4. Studies on the cooling minimum quantity and conventional cooling at hardened steels in grinding process

    OpenAIRE

    Paulo Roberto Aguiar; Rodrigo Eduardo Catai; Eduardo Carlos Bianchi; Roberto de Freitas

    2007-01-01

    The purpose of this work is to explain the concept of cutting fluids reasonable usage through the fluid minimum quantity in grinding processes. On that purpose, the development of a new nozzle and an own and adequate methodology should be required in order to obtain good results and compare them to the conventional methods. The analysis of the grinding wheel/cutting fluid performance was accomplished from the following input parameters: flow rate variation by nozzle diameter changes (three di...

  5. Research on Static and Dynamic Performance of Spindle System of the Grinding Head

    OpenAIRE

    Jin-Ling Cao; Ying Luo

    2013-01-01

    The article studied the vibration resistance of spindle system in grinding head of roller grinding machine by means of harmonic response and modal analysis, the system modal analysis use the method of the transfer matrix, obtained the first five orders of the natural frequency of spindle system, calculated the natural frequency of spindle system by the displacement-frequency curve of the spindle system harmonic response. By studying the M84100A type spindle ...

  6. Modification of the magnetic properties of SmCo5 particles depending on the grinding atmosphere

    OpenAIRE

    Kahn, Myrtil L.; Bobet, Jean-Louis; Weill, François; Chevalier, Bernard

    2002-01-01

    Particles of SmCo5 were synthesized and ground mechanically under two different gaseous atmospheres (Ar or H2). The influence of the gaseous atmosphere on the crystallinity, the morphology of the particles and their magneticproperties has been studied. The major differences in terms of crystallinity and morphology are reached after 20 min of grinding. The sample ground under H2 is still well crystallized whereas the homologous sample ground under Ar is almost amorphous. For longer grinding ti...

  7. Application of the Minimum Quantity Lubrication (MQL) technique in the plunge cylindrical grinding operation

    OpenAIRE

    José Augusto Camargo Alves; Ulysses de Barros Fernandes; Carlos Elias da Silva Júnior; Eduardo Carlos Bianchi; Paulo Roberto Aguiar; Eraldo Jannone da Silva

    2009-01-01

    Precision cylindrical grinding is used extensively in the manufacture of precision components in the metal-mechanical industry in general. Modern CNC grinding machines have improved this process with respect to the positioning and rigidity of the machine-workpiece-tool system, allowing the production of high precision parts with low dimensional tolerances. Besides the difficulties inherent to the process, awareness has grown in recent years regarding the environmental issues of cutting fluids...

  8. 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.

  9. Co-processing of Grinding Sludge as Alternative Raw Material in Portland Cement Clinker Production

    Directory of Open Access Journals (Sweden)

    M. Wecharatana

    2010-01-01

    Full Text Available This research aimed to investigate the potential of partial substitution of cement raw meal with grinding sludge as an alternative raw material in Portland cement clinker production. Cement raw mixtures with up to 3% raw mix replacement were put through a burning process in a high-temperature furnace. One reference and three modified mixtures, containing 1, 2 and 3% dry weight of grinding sludge were examined. XRF analysis results showed that CaO, SiO2, Al2O3 and Fe2O3 in ordinary cement raw meal were within typical concentration ranges. The grinding sludge had high concentrations of iron, cadmium, chromium and nickel and was consequently classified as a hazardous waste. High Fe2O3 made the grinding sludge a good candidate for alternative raw material. Higher replacement of grinding sludge was found to improve burnability, reduce formation of major of cement compositions (dicalcium silicate, C2S and tricalcium aluminate, C3A, lower in silica and alumina ratios, but promote the formation of tricalcium silicate (C3S and tetracalcium aluminateferrite (C4AF. Microstructural analysis of the synthesized Portland clinker revealed that the grinding sludge promoted formation of secondary C2S as well as caused color change of C3S. Thai regulatory leaching procedure was performed on the synthesized clinker and mortar samples. The concentrations of heavy metals in the leachate were found below the limits. Moreover, the maximum substitution of grinding sludge was found to be 2% of grinding sludge. Thus, this sludge has potential applications as an alternative raw material in cement production.

  10. Pyrite-pyrrhotite grinding media interactions and their effects on media wear and flotation

    Energy Technology Data Exchange (ETDEWEB)

    Pozzo, R.L. (Instituto de Desarrollo Technologico, Para la Industria Quimica, Sante Fe (AR)); Iwasaki, I. (Minnesota Univ., Minneapolis, MN (USA). Mineral Resources Research Center)

    1989-06-01

    The electrochemistry of mineral-grinding media interactions in the wet grinding of one- and two-sulfide mineral ores is discussed with respect to the corrosive wear of the media and the flotation behaviors of the minerals. Electrochemical studies with mineral and steel electrodes under abrasive and nonabrasive conditions are correlated with the data from marked ball wear tests, and from microflotation and laboratory batch flotation tests.

  11. Cell sorting by deterministic cell rolling

    OpenAIRE

    Choi, Sungyoung; Karp, Jeffrey M; Karnik, Rohit

    2011-01-01

    This communication presents the concept of “deterministic cell rolling”, which leverages transient cell-surface molecular interactions that mediate cell rolling to sort cells with high purity and efficiency in a single step.

  12. Effect of surface shear on cube texture formation in heavy cold-rolled Cu-45 at%Ni alloy substrates

    DEFF Research Database (Denmark)

    Tian, Hui; Suo, Hongli

    2015-01-01

    Two types of Cu-45 at%Ni alloy thin tapes with and without surface shear were obtained by different heavy cold rolling processes. The deformation and recrystallization textures of the two tapes were thoroughly investigated by electron back scattering diffraction technique. The results showed that a shear texture mainly covered the surface of the heavy deformed tapes because of the fraction between the surface of rolling mills and the thin tapes when the rolling force strongly reduced at high strain, which significantly reduced the fraction of rolling texture on the surface of the Cu-45at %Ni alloy thin tapes, retarded the cube grain growth during recrystallization and affected the strong cube texture formation after high temperature annealing.

  13. 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.

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

    International Nuclear Information System (INIS)

    Highlights: ? The pyrolysis of reinforcing fibres obtained from scrap tyres has been studied. ? The results have been compared to scrap tyre granules. ? A higher temperature is needed for the total decomposition of the fibres. ? More compounds with heteroatoms (O, N) were found in the oil from the fibres. ? 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 °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 N2 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.

  15. Modeling Asymmetric Rolling Process of Mg alloys

    International Nuclear Information System (INIS)

    Asymmetric deformation during rolling can arise in various ways: difference in the radii, speeds, frictions of the top and bottom rolls. Asymmetric warm rolling processes of magnesium alloys were modeled using a lagrangian incremental approach. A constitutive equation representing flow behaviors of AZ31 magnesium alloys during warm deformation was implemented to the modeling. Various roll speed ratios were introduced to investigate deformation behaviors of the magnesium alloys. Bending and texturing of the strips were examined.

  16. On an Interpretation of Mill’s Qualitative Utilitarianism

    Directory of Open Access Journals (Sweden)

    CHRISTOPH SCHMIDT-PETRI

    2006-12-01

    Full Text Available This paper is a reply to Jonathan Riley’s criticism of my reading of Mill(both published in the Philosophical Quarterly 2003. I show that Riley’s interpretation has no textual support in Mill’s writing by putting the supposedly supporting quotations in their proper context. Secondly it is demonstrated how my reading is not incompatible with hedonism. Mill’s use of the concepts of ‘quality’, ‘quantity’, and ‘pleasure’ are explained and illustrated. I conclude by considering whether the possible redundancy of Mill’s quality/quantity discussion would be problematic.

  17. Rolling Tachyon in Nonlocal Cosmology

    OpenAIRE

    Joukovskaya, L.

    2007-01-01

    Nonlocal cosmological models derived from String Field Theory are considered. A new method for constructing rolling tachyon solutions in the FRW metric in two field configuration is proposed and solutions of the Friedman equations with nonlocal operator are presented. The cosmological properties of these solutions are discussed.

  18. Rubber rolling over a sphere

    CERN Document Server

    Koiller, J; Koiller, Jair; Ehlers, Kurt M.

    2006-01-01

    ``Rubber'' coated rolling bodies satisfy a no-twist in addition to the no slip satisfied by ``marble'' coated bodies. Rubber rolling has an interesting differential geometric appeal because the geodesic curvatures of the curves on the surfaces at the corresponding points are equal. The associated distribution in the 5 dimensional configuration space has 2-3-5 growth (these distributions were first studied by Cartan; he showed that the maximal symmetries occurs for rubber rolling of spheres with 3:1 diameters ratio and materialize the exceptionalgroup G_2. The 2-3-5 nonholonomic geometries are classified in a companion paper via Cartan's equivalence method. Rubber rolling of a convex body over a sphere defines a generalized Chaplygin system with SO(3) symmetry group, total space Q = SO(3) X S^2 that can be reduced to an almost Hamiltonian system in T^*S^2 with a non-closed 2-form \\omega_{NH}. In this paper we present some basic results on this reduction and as an example we discuss the sphere-sphere problem. I...

  19. Rolling Tachyons in String Cosmology

    OpenAIRE

    Kim, Chanju; Kim, Hang Bae; Kim, Yoonbai

    2002-01-01

    We study the role of rolling tachyons in the cosmological model with dilatonic gravity. In the string frame, flat space solutions of both initial-stage and late-time are obtained in closed form. In the Einstein frame, we show that every expanding solution is decelerating.

  20. Preparation of glibenclamide nanocrystals by a simple laboratory scale ultra cryo-milling

    International Nuclear Information System (INIS)

    The objective of this study is to evaluate the ability to reduce the particle size of glibenclamide (GBC) to the nanometric scale through a very simple and well-known laboratory scale method, the laboratory scale ultra cryo-milling. The effect of milling on GBC crystalline properties and dissolution behaviour was deliberately evaluated in the absence of any surfactants as stabilizers. The milling procedure consisted in adding particles to liquid nitrogen and milling them by hand in a mortar with a pestle for different time intervals (15, 30, 40 min). For comparison, the same milling procedure was also applied without liquid nitrogen. The particle size reduction was evaluated for the coarsest samples (>3 ?m) by measuring the particle Ferret’s diameter through scanning electron microscopy, while for the smallest one (<3 ?m) by dynamic light scattering. A time grinding of 40 min in the presence of liquid nitrogen was revealed highly efficacious to obtain particles of nanodimensions, with a geometric mean particle size of 0.55 ± 0.23 ?m and more than the 80 % of particles lower than 1,000 nm. Interestingly, non-agglomerated particles were obtained. Differential scanning calorimetry and X-ray powder diffractometry allowed to assess that under mechanical treatment no polymorphic transitions were observed, while a decrease in crystallinity degree occurred depending on the milling procedure (presence or absence of liquid nitrogen) and the milling time (crystallinity decreases at increasing milling time from 15 to 40 min). A comparison of the intrinsic dissolution rate and the dissolution from particles revealed an interesting improvement of particle dissolution particularly for particles milled in the presence of liquid nitrogen due to an increase in particle surface area and concentration gradient, according to the Noyes–Whitney equation.

  1. Thermal stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    The treatment of uranium mill tailings by high-temperature sintering (>10500C) has been investigated as a means of controlling the release of 222Rn and leachable contaminants. Thermal stabilization in laboratory trials at 12000C reduced the radon emanation of various tailings by factors ranging from 37 to 1400 depending on the mineralogy of the tailings. The leachability of most contaminants (e.g., Al, Cd, Mn, Pb, U, and Zn) was substantially reduced. The weathering of thermally stabilized tailings was simulated by grinding and leaching and appears dependent on the gypsum content and particle size distribution of the original tailings as well as the amount of amorphous material produced during thermal treatment. Pilot-scale thermal stabilization tests verified the technical feasibility of this conditioning process. A conceptual engineering design of a thermal stabilization operation has been developed around the use of coal-fired rotary cement kilns; economic analysis of remedial action alternatives at several inactive uranium processing sites indicates that the cost of thermal stabilization is comparable to relocating the tailings piles

  2. Inflation with a constant rate of roll

    OpenAIRE

    Motohashi, Hayato; Starobinsky, Alexei A.; Yokoyama, Jun'ichi

    2014-01-01

    We consider an inflationary scenario where the rate of inflaton roll defined by $\\ddot\\phi/H\\dot \\phi$ remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of `constant-roll' inflation. We find a general exact solution for the inflaton potential required for such inflaton behaviour. In this model, due to non-slow evolution of background, the would-be decaying mode of linear scalar (curvature) perturba...

  3. Analysis of diametrical wear of grinding wheel and roundness errors in the machining of steel VC 131

    Scientific Electronic Library Online (English)

    C. N. de, Souza; R. E., Catai; P. R. de, Aguiar; M. H., Salgado; E. C., Bianchi.

    2004-06-01

    Full Text Available Due to the high industrial competitiveness, the rigorous laws of environmental protection, the necessary reduction of costs, the mechanical industry sees itself forced to worry more and more with the refinement of your processes and products. In this context, can be mentioned the need to eliminate t [...] he roundness errors that appear after the grinding process. This work has the objective of verifying if optimized nozzles for the application of cutting fluid in the grinding process can minimize the formation of the roundness errors and the diametrical wear of grinding wheel in the machining of the steel VC 131 with 60 HRc, when compared to the conventional nozzles. These nozzles were analyzed using two types of grinding wheels and two different cutting fluids. Was verified that the nozzle of 3mm of diameter, integral oil and the CBN grinding wheel, were the best options to obtain smaller roundness errors and the lowest diametrical wears of grinding wheels.

  4. 76 FR 34101 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Science.gov (United States)

    2011-06-10

    ...and 731-TA-806-808 Second Review] Hot-Rolled Flat-Rolled Carbon-Quality...termination of the suspension agreement on hot- rolled flat-rolled carbon-quality...revocation of the countervailing duty order on hot-rolled flat-rolled...

  5. 77 FR 32513 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From the Russian Federation; Preliminary...

    Science.gov (United States)

    2012-06-01

    ...International Trade Administration [A-821-809] Hot-Rolled Flat-Rolled Carbon-Quality...Administrative Review of the Suspension Agreement on Hot-Rolled Flat-Rolled Carbon-Quality...Suspending the Antidumping Duty Investigation of Hot-Rolled Flat-Rolled...

  6. High speed electrical measurement for roll-to-roll nanomanufacturing

    Science.gov (United States)

    Orloff, Nathan; Long, Christian; Obrzut, Jan; Maillaud, Laurent; Mirri, Francesca; Kole, Thomas; McMichael, Robert; Pasquali, Matteo; Stranick, Stephan; Liddle, J. Alexander

    2015-03-01

    Roll-to-roll processing of nanomaterials can produce high-quality coatings and filaments continuously, enabling materials applications for electronics, fabrics, and wires. These applications often require specific electrical properties that are correlated to the material's nanostructure. While several high-throughput structural characterizations techniques exist, there are relatively few contactless options for quantifying the electrical properties of materials for nanomanufacturing. Here, we demonstrate a microwave method for measuring complex permittivity (or geometry for samples of known dielectric properties) in a millisecond. The demonstrated measurement times are suitable for current industrial needs, allowing real-time materials characterization and in-line control of processing variables without disrupting production. Address correspondence to Dr. Stephan J. Stranick, and Dr. J. Alexander Liddle.

  7. Roll-to-roll fabrication of polymer solar cells

    Directory of Open Access Journals (Sweden)

    Roar Søndergaard

    2012-01-01

    Full Text Available As the performance in terms of power conversion efficiency and operational stability for polymer and organic solar cells is rapidly approaching the key 10–10 targets (10 % efficiency and 10 years of stability the quest for efficient, scalable, and rational processing methods has begun. The 10–10 targets are being approached through consistent laboratory research efforts, which coupled with early commercial efforts have resulted in a fast moving research field and the dawning of a new industry. We review the roll-to-roll processing techniques required to bring the magnificent 10–10 targets into reality, using quick methods with low environmental impact and low cost. We also highlight some new targets related to processing speed, materials, and environmental impact.

  8. Almost rolling motion: An investigation of rolling grooved cylinders

    CERN Document Server

    Mead, L R; Mead, Lawrence R.; Bentrem, Frank W.

    1998-01-01

    We examine the dynamics of cylinders that are grooved to form N teeth for rolling motion down an inclined plane. The grooved cylinders are experimentally found to reach a terminal velocity. This result can be explained by the inclusion of inelastic processes which occur whenever a tooth hits the surface. The fraction of the angular velocity that is lost during an inelastic collision is phenomenologically found to be proportional to (2*sin^2*pi/N)-(alpha*sin^3*pi/N), and the method of least squares is used to find the constant alpha=0.98. The adjusted theoretical results for the time of rolling as well as for terminal velocity are found to be in good agreement with the experimental results.

  9. Optimization of hammer mills

    International Nuclear Information System (INIS)

    A simple mathematical model is proposed for the residence time distribution of crushed grain in hammer mills. The residence time distribution of the crushed grain, product quality, and the total energy consumption under various operation conditions (number of hammer rows, number of hammers in a row, mesh size of screen, velocity and output of the mill has been used as variables) was studied on a pilot hammer mill. The radiotracer was used for the experimental verification of the model and for the determination of a holdup (the magnitude of the rotating grist layer) on the pilot scale and partly also on the full-scale mills. The impulse responses were influenced by transport processes behind the screen. This effect had to be taken into account during the analysis of experimental data. The method of a non-linear regression analysis was applied for the evaluation of parameters of the mathematical model. (author)

  10. Influence of nanomechanical crystal properties on the comminution process of particulate solids in spiral jet mills.

    Science.gov (United States)

    Zügner, Sascha; Marquardt, Karin; Zimmermann, Ingfried

    2006-02-01

    Elastic-plastic properties of single crystals are supposed to influence the size reduction process of bulk materials during jet milling. According to Pahl [M.H. Pahl, Zerkleinerungstechnik 2. Auflage. Fachbuchverlag, Leipzig (1993)] and H. Rumpf: [Prinzipien der Prallzerkleinerung und ihre Anwendung bei der Strahlmahlung. Chem. Ing. Tech., 3(1960) 129-135.] fracture toughness, maximum strain or work of fracture for example are strongly dependent on mechanical parameters like hardness (H) and young's modulus of elasticity (E). In addition the dwell time of particles in a spiral jet mill proved to correlate with the hardness of the feed material [F. Rief: Ph. D. Thesis, University of Würzburg (2001)]. Therefore 'near-surface' properties have a direct influence on the effectiveness of the comminution process. The mean particle diameter as well as the size distribution of the ground product may vary significantly with the nanomechanical response of the material. Thus accurate measurement of crystals' hardness and modulus is essential to determine the ideal operational micronisation conditions of the spiral jet mill. The recently developed nanoindentation technique is applied to examine subsurface properties of pharmaceutical bulk materials, namely calcite, sodium ascorbate, lactose and sodium chloride. Pressing a small sized tip into the material while continuously recording load and displacement, characteristic diagrams are derived. The mathematical evaluation of the force-displacement-data allows for calculation of the hardness and the elastic modulus of the investigated material at penetration depths between 50-300 nm. Grinding experiments performed with a modified spiral jet mill (Type Fryma JMRS 80) indicate the strong impact of the elastic-plastic properties of a given substance on its breaking behaviour. The fineness of milled products produced at constant grinding conditions but with different crystalline powders varies significantly as it is dependent on the nanohardness and the elasticity of the feed material. The analysis of this correlation gives new insights into the size reduction process. PMID:16202574

  11. The effects of particle size, milling method, and thermal treatment of feed on performance, apparent ileal digestibility, and pH of the digesta in laying hens.

    Science.gov (United States)

    Ruhnke, Isabelle; Röhe, Ilen; Krämer, Carolin; Goodarzi Boroojeni, Farshad; Knorr, Fanny; Mader, Anneluise; Schulze, Erin; Hafeez, Abdul; Neumann, Konrad; Löwe, Rainer; Zentek, Jürgen

    2015-04-01

    Various milling methods result in different particle size distributions and, in combination with mash and thermal treatment (expandate) of the feed, may have an impact on nutrient digestibility, pH of the digesta and subsequently the performance of an animal. Since this aspect has not been widely considered in laying hens, the objective of the present study was to investigate the effects of milling method, expansion, and particle size of feed on performance, apparent ileal nutrient digestibility, and pH of digesta in laying hens. Twelve variants of the same diet were produced. Four different milling techniques (hammer mill, roller mill, disc mill, and wedge-shaped disc mill) were used to grind the feed cereals. Coarse feed was obtained from all four mills. Additionally, fine feed was obtained from the hammer mill and the roller mill. Each of the six feed variants was offered as mash or expandate, resulting in a total of 12 treatments. The duration of the experimental period was 21 days. A total of 576 layers, each 19 weeks of age, were used in eight replicates. The statistical analysis for the four milling methods and two thermal treatments was performed using a 4×2 factorial arrangement. The effect of particle size was investigated using a 2×2×2 factorial arrangement including the coarse and fine particle sizes that were produced with the hammer mill and the roller mill as well as the mash and expandate. The animal performance and the pH of the digesta were not affected by the treatments. Ileal digestibility of starch was significantly improved by feeding mash compared to expandate (P=0.013) and by feeding coarse compared to fine feed (P=0.028). Based on this study, the tested milling methods can be used for the production of feed for laying hens without affecting performance and digestibility of nutrients. PMID:25717083

  12. Evaluation of the thermal damages in inlet engine valves varying the grinding wheels and the cutting fluids

    OpenAIRE

    Eduardo Carlos Bianchi; Eraldo Janonne da Silva; Paulo Roberto Aguiar; Rodrigo Eduardo Catai

    2003-01-01

    This paper presents an experimental research in which the thermal damage in inlet engine valves grinding was evaluated. Four different cutting fluids and two grinding wheel were tested and were analyzed the workpiece residual stress, the micro hardness and the optical observation of the workpiece microstructure. The cutting fluid and the grinding wheel types adopted resulted in different types of residual stress. The cutting oil resulted in compressive residual stresses, even using the conven...

  13. Statistical Modeling of Pin Gauge Dimensions of Root of Gas Turbine Blade in Creep Feed Grinding Process

    OpenAIRE

    Ahmad Reza Fazeli

    2010-01-01

    Creep feed grinding is a recently invented process of material handling. It combines high quality of the piece surface, productivity, and the possibility of automatic control. The main objectives of this research is to study the influences of major process parameters and their interactions of creep feed grinding process such as wheel speed, workpiece speed, grinding depth, and dresser speed on the pin gauge dimensions of root of gas turbine blade by design of experiments (DOE). Experimental r...

  14. The effect of roll gap geometry on microstructure in cold-rolled aluminum

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bay, B.

    2004-01-01

    Microstructure and texture are analyzed through the thickness of two aluminum plates cold-rolled 40% with different roll gap geometries. It is found that both texture and microstructure are strongly affected by the rolling geometry. After rolling with intermediate-size draughts a rolling-type texture is developed throughout the plate thickness. In this case, grains are subdivided by extended planar dislocation boundaries preferentially aligned at an angle of 40 +/- 15degrees to the rolling direction. In the plate rolled with small draughts, shear texture components appear in the intermediate layers. In these layers, extended planar dislocation boundaries are frequently found to be inclined closely to the rolling direction. The subsurface and central layers of this plate exhibit microstructures similar to those in the plate rolled with intermediate draughts. It is suggested that the development of different textures and microstructures at different depths is related to the activation of different slip systems due to through-thickness strain gradients.

  15. Development of rolling magnetic microrobots

    International Nuclear Information System (INIS)

    This paper reports magnetic microrobots with rolling capability. A magnetic object subjected to an externally rotating magnetic field would be rotated due to the tendency of alignment between its internal magnetization and the field. Based on this principle, a magnetic microrobot in a spherical body with a diameter of several hundred microns was designed and fabricated. To remotely power and control the microrobot, a rotating magnet was used to generate a rotating magnetic field. Driven by this field, the microrobot can freely roll on three-dimensional surfaces. These surfaces can be in air, water or silicon oil. In a dry environment, a microrobot with a diameter of 440 µm achieved a maximum linear speed of 13.2 mm s?1.

  16. Generalized Slow Roll for Tensors

    OpenAIRE

    Hu, Wayne

    2014-01-01

    The recent BICEP2 detection of degree scale CMB B-mode polarization, coupled with a deficit of observed power in large angle temperature anisotropy, suggest that the slow-roll parameter $\\epsilon_H$, the fractional variation in the Hubble rate per efold, is both relatively large and may evolve from an even larger value on scales greater than the horizon at recombination. The relatively large tensor contribution implied also requires finite matching features in the tensor pow...

  17. Micromagnetic testing for rolled steel

    OpenAIRE

    Wolter, B.; Dobmann, G.

    2006-01-01

    In forming of steel by hot and cold rolling a broad range of semi-finished and final products can be produced with very specific, custom-tailored technological properties. Here, the characteristics of mechanical-technological tests (tensile, hardness, creep, fatigue test) are often of central importance. Obviously the traditionally process orientated steel industry has a strong interest to replace timeconsuming and expensive destructive mechanical tests by non-destructive (nd) methods, which ...

  18. Generalized Slow Roll for Tensors

    CERN Document Server

    Hu, Wayne

    2014-01-01

    The recent BICEP2 detection of degree scale CMB B-mode polarization, coupled with a deficit of observed power in large angle temperature anisotropy, suggest that the slow-roll parameter $\\epsilon_H$, the fractional variation in the Hubble rate per efold, is both relatively large and may evolve from an even larger value on scales greater than the horizon at recombination. The relatively large tensor contribution implied also requires finite matching features in the tensor power spectrum for any scalar power spectrum feature proposed to explain anomalies in the temperature data. We extend the generalized slow-roll approach for computing power spectra, appropriate for such models where the slow-roll parameters vary, to tensor features where scalar features are large. This approach also generalizes the tensor-scalar consistency relation to be between the ratio of tensor and scalar sources and features in the two power spectra. Features in the tensor spectrum are generically suppressed by $\\epsilon_H$ relative tho...

  19. Rolling Contact Fatigue of Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Wang, W. [Bournemouth University, Bournemouth, United Kingdom; Wang, Y. [Bournemouth University, Bournemouth, United Kingdom; Hadfield, M. [Bournemouth University, Bournemouth, United Kingdom; Kanematsu, W. [National Institute of Advanced Industrial Science and Technology, Japan; Kirkland, Timothy Philip [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville

    2006-09-01

    High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.

  20. Westinghouse Modular Grinding Process - Enhancement of Volume Reduction for Hot Resin Supercompaction - 13491

    Energy Technology Data Exchange (ETDEWEB)

    Fehrmann, Henning [Westinghouse Electric Germany GmbH, Dudenstr. 44, D-68167 Mannheim (Germany); Aign, Joerg [Westinghouse Electric Germany GmbH, Global D and D and Waste Management, Tarpenring 6, D-22419 Hamburg (Germany)

    2013-07-01

    In nuclear power plants (NPP) ion exchange (IX) resins are used in several systems for water treatment. Spent resins can contain a significant amount of contaminates which makes treatment for disposal of spent resins mandatory. Several treatment processes are available such as direct immobilization with technologies like cementation, bitumisation, polymer solidification or usage of a high integrity container (HIC). These technologies usually come with a significant increase in final waste volume. The Hot Resin Supercompaction (HRSC) is a thermal treatment process which reduces the resin waste volume significantly. For a mixture of powdered and bead resins the HRSC process has demonstrated a volume reduction of up to 75 % [1]. For bead resins only the HRSC process is challenging because the bead resins compaction properties are unfavorable. The bead resin material does not form a solid block after compaction and shows a high spring back effect. The volume reduction of bead resins is not as good as for the mixture described in [1]. The compaction properties of bead resin waste can be significantly improved by grinding the beads to powder. The grinding also eliminates the need for a powder additive.Westinghouse has developed a modular grinding process to grind the bead resin to powder. The developed process requires no circulation of resins and enables a selective adjustment of particle size and distribution to achieve optimal results in the HRSC or in any other following process. A special grinding tool setup is use to minimize maintenance and radiation exposure to personnel. (authors)

  1. Chemical and sensorial characteristics of espresso coffee as affected by grinding and torrefacto roast.

    Science.gov (United States)

    Andueza, Susana; De Peña, M Paz; Cid, Concepción

    2003-11-19

    Grinding is a critical step in the preparation of espresso coffee (EC). The addition of sugar during the torrefacto roasting process could influence the degree of brittleness and grinding. The aim of this work was to study the influence of the grinding grades (coarse, fine, and very fine) in Arabica/Robusta 20:80, natural roasted (A20:R80), and Arabica/Robusta 20:80 with 50% Robusta torrefacto roasted (A20:R80 50% torrefacto) on the chemical and sensorial characteristics of EC in order to select the optimal espresso grinding grade. A higher percentage of coarse particles was found in A20:R80 ground coffee. In both ECs, the extraction of solids and soluble and aroma compounds increased inversely with particle size. Higher foam indices and extraction yields were found in A20:R80 50% torrefacto ECs probably due to the solubilization of caramelized sugar and melanoidins. It has been suggested that the range of an acceptable extraction yield could be extended to 25% in A20:R80 50% torrefacto ECs. In conclusion, the optimal grinding grade for the obtainment of an EC with A20:R80 was fine and that for A20:R80 50% torrefacto was coarse. PMID:14611167

  2. The use of cylindrical grinding to produce a martensitic structure on the surface of 4340 Steel

    Scientific Electronic Library Online (English)

    André de, Lima; Luiz Sérgio, Gâmbaro; Milton, Vieira Junior; Elesandro Antonio, Baptista.

    2011-03-01

    Full Text Available Grinding is one of the most widely used manufacturing processes and, in the last few decades, has developed considerably. An example of these developments is hardening by grinding, an operation that is being studied to provide an option to the conventional hardening processes. This study presents th [...] e use of a cylindrical grinding process to produce a martensitic structure on the surface of SAE 4340 steel workpieces, and aims at adjusting the parameters of this process. To do much, a set of experiments were carried out using three cycles of grinding: the first one just to obtain a workpiece with regular diameter; the second cycle is that which will provide heating and cooling of the ground workpiece; and the last cycle is to provide corrections to the dimensions and roughness. Results of the experiments showed that hardening by grinding is possible and that the workpiece achieved hardness levels compatible to those provided by the conventional hardening processes. The use of such a process for surface hardening purposes has been researched and developed with a view to increasing the productivity of the process, ensuring dimensional and surface quality, in addition to mechanical resistance.

  3. Cryogenic grinding of electrospun poly-{epsilon}-caprolactone mesh submerged in liquid media

    Energy Technology Data Exchange (ETDEWEB)

    Knotek, Petr [University of Pardubice, Faculty of Chemical Technology, Studentska 573, 532 10 Pardubice (Czech Republic); Pouzar, Miloslav, E-mail: milan.pouzar@upce.cz [University of Pardubice, Institute of Environmental and Chemical Engineering, Studentska 573, 530 12 Pardubice (Czech Republic); Buzgo, Matej [Department of Biophysics, 2nd Faculty of Medicine, Charles University in Prague, V Uvalu 84, 150 06, Prague 5 (Czech Republic); Laboratory of Tissue Engineering, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, v.v.i, Videnska 1083,142 20, Prague 4 (Czech Republic); Krizkova, Barbora [University of Pardubice, Department of Biological and Biochemical Sciences, Studentska 573, 530 12 Pardubice (Czech Republic); Vlcek, Milan [Institute of Macromolecular Chemistry, Academy of Sciences of Czech Republic, v.v.i., Heyrovskeho sq. 2, 162 06 Prague (Czech Republic); Mickova, Andrea; Plencner, Martin [Department of Biophysics, 2nd Faculty of Medicine, Charles University in Prague, V Uvalu 84, 150 06, Prague 5 (Czech Republic); Laboratory of Tissue Engineering, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, v.v.i, Videnska 1083,142 20, Prague 4 (Czech Republic); Navesnik, Jakub [University of Pardubice, Institute of Environmental and Chemical Engineering, Studentska 573, 530 12 Pardubice (Czech Republic); and others

    2012-08-01

    In this paper, the treatment of poly-{epsilon}-caprolactone (PCL) nano/micro-mesh system by cryogenic grinding and subsequent characterization of obtained product is described. The PCL nano/micro-mesh layer submerged in appropriate liquid was cryogenically ground and obtained particles were characterized employing mainly laser diffraction and scanning electron microscopy (SEM). In the ground sample, different types of particles (fibrous particles, fibrous fragments, agglomerates with and without an internal fibrous structure, lamellae and nanoparticles) were identified, described and quantified. Parameters of cryogenic grinding (weight of sample, type of liquid medium, and influence of sample storage) were optimized to maximize the yield of particles with desired features. The potential of the system for cell scaffolding was demonstrated by cultivation of 3T3 fibroblasts on the produced microparticles. - Research Highlights: Black-Right-Pointing-Pointer The original concept of cryogenic grinding in frozen liquids was used. Black-Right-Pointing-Pointer Optimisation of particular grinding parameters was performed. Black-Right-Pointing-Pointer Original approach was used for description of product of cryogenic grinding. Black-Right-Pointing-Pointer Fibrous particles usable as a scaffold systems and injectable gels were made.

  4. Cryogenic grinding of electrospun poly-?-caprolactone mesh submerged in liquid media

    International Nuclear Information System (INIS)

    In this paper, the treatment of poly-?-caprolactone (PCL) nano/micro-mesh system by cryogenic grinding and subsequent characterization of obtained product is described. The PCL nano/micro-mesh layer submerged in appropriate liquid was cryogenically ground and obtained particles were characterized employing mainly laser diffraction and scanning electron microscopy (SEM). In the ground sample, different types of particles (fibrous particles, fibrous fragments, agglomerates with and without an internal fibrous structure, lamellae and nanoparticles) were identified, described and quantified. Parameters of cryogenic grinding (weight of sample, type of liquid medium, and influence of sample storage) were optimized to maximize the yield of particles with desired features. The potential of the system for cell scaffolding was demonstrated by cultivation of 3T3 fibroblasts on the produced microparticles. - Research Highlights: ? The original concept of cryogenic grinding in frozen liquids was used. ? Optimisation of particular grinding parameters was performed. ? Original approach was used for description of product of cryogenic grinding. ? Fibrous particles usable as a scaffold systems and injectable gels were made.

  5. A study on grinding surface waviness of woven ceramic matrix composites

    Science.gov (United States)

    Cao, Xiaoyan; Lin, Bin; Zhang, Xiaofeng

    2013-04-01

    It is difficult to evaluate and predict the mechanical surface quality of woven ceramic matrix composites due to their anisotropic and non-homogeneous structure. The present paper proposed a new method of evaluating grinding surface quality on composites by the study on surface waviness. Using a non-contact optical measurement instrument, the method was developed on 2.5D SiO2/SiO2 composite. Three-dimensional (3D) surface characterization parameters were calculated to evaluate the surface waviness. Then the results were verified by an experiment using a contact surface profile measurement instrument. The formation mechanism of the waviness is also analysed in this paper according to knowledge on mechanical damage phenomenology. Fiber orientation plays the decisive role in grinding surface waviness of woven ceramic matrix composites, which is different from traditional waviness formation theory caused by machine tool system vibration. And we found some outstanding characteristics of the surface waviness. If the tow was perpendicular to the grinding surface, the surface waviness was properly on wave crest. while if the tow was parallel to the grinding surface, it was properly on wave trough. Based on the results obtained, grinding surface waviness of composites can be predicted, then it is expected to provide a useful guideline for optimizing the use performance such as assembling, sealing, lubricity, etc.

  6. OPTIMIZATION OF SURFACE GRINDING PROCESS PARAMETERS FOR AISI D2 STEEL

    Directory of Open Access Journals (Sweden)

    T. V. Mahajan

    2015-07-01

    Full Text Available In grinding process, Surface quality and metal removal rate are the two important performance characteristics to be consider. In this paper, Taguchi L9 orthogonal array optimization method has been used to determine the optimum machining parameters in Surface grinding process operation on AISI D2 steel. The parameters considered in this paper are grinding wheel abrasive grain size, wheel speed, table speed and depth of cut. Empirical models are developed for surface roughness and metal removal rate by considering above parameters as control factors. Optimum machining parameters leading to maximum metal removal rate and minimum surface roughness has been determined by using Taguchi L9 orthogonal array method and the adequacy of the developed model is tested with analysis of variance (ANNOVA. The experiment has been conducted on special purpose grinding machine. The developed model can be used by the different manufacturing firms for the production of surface grinding machine for hardened steel. They can select appropriate combination of machining parameters to achieve an optimal metal removal rate (MRR and surface roughness (Ra. The results were further validated by conducting confirmation experiments.

  7. Roll-to-roll fabricated lab-on-a-chip devices

    OpenAIRE

    Vig, Asger Laurberg; Mäkelä, Tapio; Majander, Päivi; Lambertini, Vito; Ahopelto, Jouni; Kristensen, Andrs

    2011-01-01

    We present a high-volume fabrication technique for making polymer lab-on-a-chip devices. Microfluidic separation devices, relying on pinched flow fraction, are roll-to-roll fabricated in a cellulose acetate (CA) film at a volume of 360 devices h?1 for a cost of approximately 0.5 euro/device. The manufacturing process consists of two steps: (i) roll-to-roll thermal nanoimprint for patterning the microchannels into a CA film and (ii) roll-to-roll lamination for bonding another CA film onto the ...

  8. Roll-to-roll fabricated lab-on-a-chip devices

    DEFF Research Database (Denmark)

    Vig, Asger Laurberg; Mäkelä, Tapio; Majander, Päivi; Lambertini, Vito; Ahopelto, Jouni; Kristensen, Anders

    2011-01-01

    We present a high-volume fabrication technique for making polymer lab-on-a-chip devices. Microfluidic separation devices, relying on pinched flow fraction, are roll-to-roll fabricated in a cellulose acetate (CA) film at a volume of 360 devices h?1 for a cost of approximately 0.5 euro/device. The manufacturing process consists of two steps: (i) roll-to-roll thermal nanoimprint for patterning the microchannels into a CA film and (ii) roll-to-roll lamination for bonding another CA film onto the imp...

  9. 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.

  10. 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)

  11. Optimization of bead milling parameters for the cell disruption of microalgae: Process modeling and application to Porphyridium cruentum and Nannochloropsis oculata.

    Science.gov (United States)

    Montalescot, V; Rinaldi, T; Touchard, R; Jubeau, S; Frappart, M; Jaouen, P; Bourseau, P; Marchal, L

    2015-11-01

    A study of cell disruption by bead milling for two microalgae, Nannochloropsis oculata and Porphyridium cruentum, was performed. Strains robustness was quantified by high-pressure disruption assays. The hydrodynamics in the bead mill grinding chamber was studied by Residence Time Distribution modeling. Operating parameters effects were analyzed and modeled in terms of stress intensities and stress number. RTD corresponded to a 2 CSTR in series model. First order kinetics cell disruption was modeled in consequence. Continuous bead milling was efficient for both strains disruption. SI-SN modeling was successfully adapted to microalgae. As predicted by high pressure assays, N. oculata was more resistant than P. cruentum. The critical stress intensity was twice more important for N. oculata than for P. cruentum. SI-SN modeling allows the determination of operating parameters minimizing energy consumption and gives a scalable approach to develop and optimize microalgal disruption by bead milling. PMID:26253918

  12. Application of the Minimum Quantity Lubrication (MQL) technique in the plunge cylindrical grinding operation

    Scientific Electronic Library Online (English)

    José Augusto Camargo, Alves; Ulysses de Barros, Fernandes; Carlos Elias da, Silva Júnior; Eduardo Carlos, Bianchi; Paulo Roberto de, Aguiar; Eraldo Jannone da, Silva.

    2009-03-01

    Full Text Available Precision cylindrical grinding is used extensively in the manufacture of precision components in the metal-mechanical industry in general. Modern CNC grinding machines have improved this process with respect to the positioning and rigidity of the machine-workpiece-tool system, allowing the productio [...] n of high precision parts with low dimensional tolerances. Besides the difficulties inherent to the process, awareness has grown in recent years regarding the environmental issues of cutting fluids. As a response, the industry has begun to seek alternative lubrication and cooling methods. Among the various existing techniques, Minimum Quantity Lubrication (MQL) has been considered as an alternative. This technique can be understood as a combination of conventional lubrication and cooling methods and dry machining, in which a small quantity of lubricating oil mixed with compressed air flow is delivered in the wheel-workpiece interface. The MQL technique is already widely employed in machining processes with tools of defined geometry (e.g. turning), in which produces very satisfactory results. However, the MQL technique has been little explored in grinding processes (non-defined tool geometry), in which the really effective heat removal methods are required due to the frictional heat generation in the grinding zone. Consequently, the aim of this study was to evaluate the plunge cylindrical internal grinding operation when using the MQL technique and the conventional cooling method. Roughness and roundness were the outputparameters. As a result, it was found that the best values of roughness Ra were obtained with the conventional lubrication method. The MQL technique applied as proposed was not able to flush the chips away from the grinding zone, leading to the highest Ra values. No significant differences were detected among the cooling methods when analyzing the roundness results. The workpiece fixture method selected was responsible for the overall unsatisfactory results.

  13. Chemical composition and morphology of welding fume particles and grinding dusts.

    Science.gov (United States)

    Karlsen, J T; Farrants, G; Torgrimsen, T; Reith, A

    1992-05-01

    Elemental composition and morphology of pure manual metal arc (MMA) welding fumes, pure grinding dust, and combined fume/dust air samples were collected and determined separately under semilaboratory conditions. The base material was stainless steel. The purpose of the present study was to create a "synthetic" work situation under semilaboratory conditions by combining one grinding period and two MMA welding periods and comparing these results with results during welding in a workshop. The duty cycles of pure welding and of pure grinding were also observed. A comparison was also made between metal inert gas (MIG) and MMA welding on stainless steel as well as a nickel-rich alloy under regular conditions. The amount of collected material was determined by weighing the membrane filters before and after exposure, and the element contents were determined by atomic spectroscopy. Other transmission electron microscopy (TEM) filters were used for TEM and computer-image analysis, in which the amount of collected material and its morphological characteristics were observed. The arcing time and the consumption of filler material were estimated for different kinds of electrodes. Chemical analysis showed that the contents of manganese and total chromium were lower in grinding dust than in welding fumes. The contents of hexavalent chromium, Cr(VI), in grinding dust were undetectable. Samples collected in welding shops where concomitant grinding was performed contained about 30% less Cr(VI) than those collected under laboratory conditions during welding only. The sizes and shapes of the particles depend on the welding process and distance of collection from the plume of the fume. To compare laboratory experiments with regular welding situations, the experiment must resemble industrial welding.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1609739

  14. Study of reissner beam under rolling disk

    OpenAIRE

    Jursinovi?, Boštjan

    2011-01-01

    For this degree paper we developed two-dimensional mathematical model of a rigid body rolling motion on deformable surface. Rigid body was modeled as a disk and deformable surface with geometrically non-linear beam. We derived equations of the rolling disk on know curve line, equations of dynamical response of Reissner beam under point load and equations of coupled rolling of disk on geometrical non-linear beam. Equations are discretized first with respect to the length of the beam followin...

  15. CRITICAL WAVE EPISODES FOR ASSESSMENT OF ROLL

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Pedersen, Preben Terndrup

    2006-01-01

    The statistical distribution of parametric induced roll angles is estimated using the first order reliability method (FORM), well-known from structural reliability problems. To illustrate the proposed procedure the roll motion is modeled by a simplified non-linear procedure taking into account the time-varying restoring moment and the heave acceleration. The result is the mean outcrossing rate of the roll angle together with corresponding most probable wave scenarios (critical wave episodes), le...

  16. Cold roll forming process energy efficiency optimization

    OpenAIRE

    ?????????, ???????

    2012-01-01

    The objective of the current study is the development of an optimization methodology for the energy efficiency of the cold roll forming process. Towards that target, a hybrid modeling approach, utilizing analytical and computational models, is proposed and developed. The energy efficiency indicator for the cold roll forming process is defined, as taking into account the cold roll forming process as a system with energy inputs and outputs. An analytical model was proposed and analyzed fo...

  17. Simulations of Gear Rolling by Flat Tools

    OpenAIRE

    Saleem, Adil

    2013-01-01

    Gear rolling is one of the latest techniques being used in gear manufacturing. As compared to traditional gear manufacturing techniques, gear rolling can add benefits like improved surface finish, increased flank strength, increased load capacity and less material usage. After initial research initiatives in USA, Germany and China, efforts are underway to make this technique industrially viable for production of both low and high module gears. There are two methods for gear rolling one uses r...

  18. Large-area, continuous roll-to-roll nanoimprinting with PFPE composite molds

    International Nuclear Information System (INIS)

    Successful implementation of a high-speed roll-to-roll nanoimprinting technique for continuous manufacturing of electronic devices has been hindered due to lack of simple substrate preparation steps, as well as lack of durable and long lasting molds that can faithfully replicate nanofeatures with high fidelity over hundreds of imprinting cycles. In this work, we demonstrate large-area high-speed continuous roll-to-roll nanoimprinting of 1D and 2D micron to sub-100 nm features on flexible substrate using perfluoropolyether (PFPE) composite molds on a custom designed roll-to-roll nanoimprinter. The efficiency and reliability of the PFPE based mold for the dynamic roll-to-roll patterning process was investigated. The PFPE composite mold replicated nanofeatures with high fidelity and maintained superb mold performance in terms of dimensional integrity of the nanofeatures, nearly defect free pattern transfer and exceptional mold recovering capability throughout hundreds of imprinting cycles. (paper)

  19. Co-processing of Grinding Sludge as Alternative Raw Material in Portland Cement Clinker Production

    OpenAIRE

    M. Wecharatana; A. Imyim; M. Rachakornkij; T. Punmatharith

    2010-01-01

    This research aimed to investigate the potential of partial substitution of cement raw meal with grinding sludge as an alternative raw material in Portland cement clinker production. Cement raw mixtures with up to 3% raw mix replacement were put through a burning process in a high-temperature furnace. One reference and three modified mixtures, containing 1, 2 and 3% dry weight of grinding sludge were examined. XRF analysis results showed that CaO, SiO2, Al2O3 and Fe2O3 in ordinary cement raw ...

  20. A Framework for Rolling Stock Rescheduling

    DEFF Research Database (Denmark)

    Haahr, JØrgen Thorlund; Lusby, Richard Martin

    Rolling Stock schedules are typically made months or weeks prior to the date of execution. It is, however, rare that everything goes exactly as planned due to internal and external factors on the day of operation. If the magnitude of the disturbances is small then the problems may be absorbed by network buffer times. However, if the problems are more severe, changes must be made to the rolling stock schedule. In this talk we will discuss the Rolling Stock Rescheduling problem and Disruption Management. We will present our current work and planned future work on a framework for solving the Rolling Stock in a disruption context.

  1. Interactions Between Stably Rolling Leukocytes In Vivo

    CERN Document Server

    King, M R; Kim, M B; Sarelius, I H; King, Michael R.; Ruscio, Aimee D.; Kim, Michael B.; Sarelius, Ingrid H.

    2003-01-01

    We have characterized the two-dimensional spatial dependence of the hydrodynamic interactions between two adhesively rolling leukocytes in a live venule in the mouse cremaster muscle. Two rolling leukocytes were observed to slow each other down when rolling together in close proximity, due to mutual sheltering from the external blood flow in the vessel lumen. These results are in agreement with a previous study of leukocyte rolling interactions using carbohydrate-coated beads in a parallel-plate flow chamber and a detailed computer model of adhesion in a multicellular environment.

  2. Terras: NATO õppuste roll Euroopas kasvab

    Index Scriptorium Estoniae

    2013-01-01

    Kaitseväe juhataja kindralmajor Riho Terrase sõnul suureneb lähiaastatel NATO õppuste roll Euroopas, sest Afganistanis sõdides saadud kogemust on vaja säilitada ning kasutada seda kollektiivkaitse tugevdamiseks

  3. Yang-Mills and Beyond

    OpenAIRE

    Marateck, Samuel

    2011-01-01

    In their 1954 paper, Yang and Mills invented the non-Abelian field strength to satisfy certain criteria but didn't explain how it could be derived. In the penultimate section we show how the Yang-Mills field strength derives from Yang's gauge transformation. The preceding sections place Yang-Mills theory in historical perspective and cover material relating to the field strength. The final section shows how Yang-Mills theory was combined with spontaneous symmetry breaking, t...

  4. Finite Element Analysis of Symmetric and Asymmetric Three-roll Rolling Process

    Directory of Open Access Journals (Sweden)

    Pesin A.

    2015-01-01

    Full Text Available A three-roll process is a significant technique in the production of wire rod, round bars and hexagonal profiles for structural applications. Better mechanical properties of wire rod, round bars and hexagonal profiles can be achieved due to large plastic deformation by the three-roll process. Asymmetric rolling is a novel technique characterised by a kinematic asymmetry linked to the difference in peripheral speed of the rolls, able to introduce additional shear strains through the bar thickness. In order to achieve this, asymmetrical three-roll rolling process was investigated to better control the deformation compared to the conventional three-roll rolling process in a stand with two three-roll calibers located very close to each other. Simulation of round-triangle-triangle pass rolling was performed. FEM simulations were carried out with using software DEFORM 3D. The influence of the friction coefficient and speed asymmetry on the shear strain and material flow was discussed. The results of simulation can be used to optimize the asymmetric three-roll rolling process to improve the mechanical properties of wire rod, round bars and hexagonal profiles.

  5. 75 FR 16504 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Science.gov (United States)

    2010-04-01

    ...731-TA-806-808 (Second Review)] Hot-Rolled Flat-Rolled Carbon-Quality Steel...the countervailing duty order on certain hot-rolled flat-rolled carbon-quality steel products (``hot-rolled steel'') from Brazil, the...

  6. 75 FR 62566 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Science.gov (United States)

    2010-10-12

    ...731-TA-806-808 (Second Review)] Hot-Rolled Flat-Rolled Carbon-Quality Steel...concerning the countervailing duty order on hot-rolled flat-rolled carbon-quality steel products (``hot-rolled steel'') from Brazil, the...

  7. 75 FR 42782 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Science.gov (United States)

    2010-07-22

    ...731-TA-806-808 (Second Review)] Hot-Rolled Flat-Rolled Carbon-Quality Steel...the countervailing duty order on certain hot-rolled flat-rolled carbon-quality steel products (``hot-rolled steel'') from Brazil, the...

  8. 76 FR 22868 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil: Final Results of...

    Science.gov (United States)

    2011-04-25

    ...Hot-rolled dual phase steel, phase-hardened, primarily...hot-rolled flat- rolled carbon-quality steel...Hot-Rolled Flat-Rolled Carbon-Quality Steel...and discusses any changes since the Preliminary...destruction of APO materials or conversion...

  9. 75 FR 64254 - Certain Hot-Rolled Flat-Rolled Carbon Quality Steel Products From Brazil; Final Results of...

    Science.gov (United States)

    2010-10-19

    ...Hot-rolled dual phase steel, phase-hardened, primarily...hot-rolled flat-rolled carbon-quality steel...identical in content. Changes Since the Preliminary...Hot-Rolled Flat-Rolled Carbon Quality Steel Products...destruction of APO materials or conversion...

  10. High speed roll casting of Mg alloy strip by a vertical type twin roll caster

    OpenAIRE

    Watari, H; S.Kumai; Haga, T.

    2006-01-01

    Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm wi...

  11. Optimizing the control system of cement milling: process modeling and controller tuning based on loop shaping procedures and process simulations

    Scientific Electronic Library Online (English)

    D. C., Tsamatsoulis.

    2014-03-01

    Full Text Available Based on a dynamical model of the grinding process in closed circuit mills, efficient efforts have been made to optimize PID controllers of cement milling. The process simulation is combined with an autoregressive model of the errors between the actual process values and the computed ones. Long term [...] industrial data have been used to determine the model parameters. The data include grinding of various cement types. The M - Constrained Integral Gain Optimization (MIGO) loop shaping method is utilized to determine PID sets satisfying a certain robustness constraint. The maximum sensitivity is considered as such a criterion. Both dynamical parameters and PID sets constitute the inputs of a detailed simulator which involves all the main process characteristics. The simulation is applied over all the PID sets aiming to find the parameter region that provides the minimum integral of absolute error, which functions as a performance criterion. For each cement type a PID set is selected and put in operation in a closed circuit cement mill. The performance of the regulation is evaluated after a sufficient time period, concluding that the developed design combining criteria of both robustness and performance leads to PID controllers of high efficiency.

  12. 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.

  13. Studies on the cooling minimum quantity and conventional cooling at hardened steels in grinding process

    Scientific Electronic Library Online (English)

    Paulo Roberto de, Aguiar; Rodrigo Eduardo, Catai; Eduardo Carlos, Bianchi; Roberto de, Freitas.

    2007-06-01

    Full Text Available The purpose of this work is to explain the concept of cutting fluids reasonable usage through the fluid minimum quantity in grinding processes. On that purpose, the development of a new nozzle and an own and adequate methodology should be required in order to obtain good results and compare them to [...] the conventional methods. The analysis of the grinding wheel/cutting fluid performance was accomplished from the following input parameters: flow rate variation by nozzle diameter changes (three diameters values: 3mm, 4mm and 5mm), besides the conventional round nozzle already within the machine. Integral oil and a synthetic emulsion were used as cutting fluids and a conventional grinding wheel was employed. The workpieces were made of steel VC 131, tempered and quenched with 60HRc. Thus, as the flow rate and the nozzle diameter changes, keeping steady fluid jet velocity (equal to cutting velocity), attempted to find the best machining conditions, with the purpose to obtain a decrease on the cutting fluid volume, taking into consideration the analysis of the process output variables such as cutting strength, cutting specific energy, grinding wheel wear and surface roughness. It was verified that the 3mm diameter optimized nozzle and the integral oil, in general, was the best combination among all proposed.

  14. Fracture, grinding, mechanical activation and synthesis processes in solids under mechanical action

    OpenAIRE

    Chaikina M.V.; Aman Sergej

    2005-01-01

    The parameters of mechanical action on solids were determined for apatite and quartz as examples, providing separation between fracture, grinding and mechanical activation processes in solids. The texture, structural and chemical changes accompanying these processes in the samples under investigation are shown. The data on mechanochemical synthesis of isomorphous apatite modifications in multicomponent systems are reported. A reversible character of mechanochemical activation and mechanochemi...

  15. 13C and 15N isotopic data on grinding stones from the Guvecinkayasi site, Turkey.

    Czech Academy of Sciences Publication Activity Database

    Pavl?, Ivan; Gülçur, S.; Ja?ková, I.; Buzek, F.

    2009-01-01

    Ro?. 17, - (2009), s. 19-30. ISBN 2-906053-93-7. ISSN 1018-1946 R&D Projects: GA AV ?R IAA800020701 Institutional research plan: CEZ:AV0Z80020508 Keywords : Chalcolithic * grinding stones * Turkey Subject RIV: AC - Archeology, Anthropology, Ethnology

  16. Improving iodine homogeneity in NIST SRM 1548a Typical Diet by cryogenic grinding.

    Czech Academy of Sciences Publication Activity Database

    Ku?era, Jan; Kameník, Jan

    2015-01-01

    Ro?. 20, ?. 3 (2015), s. 189-194. ISSN 0949-1775 R&D Projects: GA ?R(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : Iodine * reference material * NIST SRM 1548a * cryogenic grinding * homogeneity Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.966, year: 2014

  17. Comparison of alternative methods, sample grinds, and fermentation times for determining indigestible neutral detergent fiber

    Science.gov (United States)

    The objectives of this study were to evaluate the effects of sample grind, fermentation method, and time on the determination of indigestible neutral detergent fiber (iNDF). Samples of: 1) alfalfa hay and silage, 2) corn stalks and silage, and 3) ryegrass and mixed grass hays were ground through 2-m...

  18. METHODOLOGY TO DETERMINE SOLUBLE CONTENT IN DRY GRIND ETHANOL COPRODUCT STREAMS

    Science.gov (United States)

    Distillers grains and syrup are coproducts from fuel ethanol dry grind processing. Ethanol manufacturing is dramatically increasing in the U.S., primarily in Midwestern states, and thus the availability of these feed products is also growing. Confusion currently exists in industrial nomenclature r...

  19. The development of an open architecture control system for CBN high speed grinding

    Scientific Electronic Library Online (English)

    E. Jannone da, Silva; M., Biffi; J. F. G. de, Oliveira.

    2004-03-01

    Full Text Available The aim of this project is the development of an open architecture controlling (OAC) system to be applied in the high speed grinding process using CBN tools. Besides other features, the system will allow a new monitoring and controlling strategy, by the adoption of open architecture CNC combined wit [...] h multi-sensors, a PC and third-party software. The OAC system will be implemented in a high speed CBN grinding machine, which is being developed in a partnership between the University of São Paulo (USP - Manufacturing Processes Optimizing Group (OPF) - NUMA - EESC; and a traditional Brazilian grinding machine manufacturer. This new CNC generation allows the implementation of new monitoring and controlling strategies due to the two-way CNC and PC communication using a High Speed Serial Bus (HSSB). As a result, third-party software routines, such as LabVIEW VIs (Virtual Instruments), can be used to act in the CNC, interacting with HMI software, via Active X. As a result, the performance of high speed grinding can be increased by the adoption of the open architecture controlling solution combined with high performance monitoring systems.

  20. Ductile grinding of silicon carbide as a production method for reflective optics

    Energy Technology Data Exchange (ETDEWEB)

    Kahl, W.K.

    1993-11-01

    Ductile regime grinding or shear-mode grinding is an enabling technology that is finding application in the optics manufacturing industry. By definition, ductile removal occurs when the scale of machining is conducted below a material-dependent critical dimension or chip size. Much of the interest in ductile grinding resides in manufacturing glass optics, which experience brittle-ductile transition at {approximately}10 nm. Silicon carbide has a critical dimension that is on the order of 100--200 nm, making it a more attractive candidate for the technology. Preliminary results from an on-axis chemical vapor deposited (CVD) SiC sphere (f/14) indicate 317 {Angstrom} surface roughness and 0.96 wave P-V figure were achieved with this manufacturing method. Surface finish, interferometric measured figure and BRDF scatter results are presented from ductile regime grinding of 40 and 75 mm flats of CVD silicon carbide, bare reaction bonded SiC (RBSiC) and uniaxial hot-pressed SiC (HPSiC).

  1. EFFECT OF LIMESTONE TYPE AND GRIND ON S02 SCRUBBER PERFORMANCE

    Science.gov (United States)

    The paper describes the effect of limestone type and grind on SO2 scrubber performance. It gives results of a comparison of the amount of limestone feed required as a function of particle size, to obtain a given SO2 removal efficiency and, thus, to verify the relative magnitude o...

  2. Trajectories of Dop Points on a Machining Wheel During Grinding of High Quality Plane Surfaces

    Science.gov (United States)

    Petrikova, I.; Vrzala, R.; Kafka, J.

    The basic requirement for plane grinding synthetic monocrystals is uniform wear of the grinding tool. This article deals with the case where the grinding process is carried out by relative motion between the front faces of rotating wheels with parallel axes. The dop is attached by the end of the pendulous arm, which movement is controlled by a cam. Kinematic relations have been drawn for the relative motion of the dop points in the reference to the abrasive wheel. The aim of the work is set the methodology for finding out of uniformity respectively nonuniformity of the motion of dop points on the abrasive wheel. The computational program was compiled in MATLAB. The sums of the number of passes were performed in the transmission range of 0.4-1. The number of passes of selected points on the dop passed over areas of the square mash was computed. The density of trajectory passes depends on four factors: the speed of both wheels, the number of arm operating cycles, the angle of the arm swings and the cam shape. All these dependencies were investigated. The uniformity the density of passes is one of the criteria for setting the grinding machine.

  3. Roll forming of eco-friendly stud

    Science.gov (United States)

    Keum, Y. T.; Lee, S. Y.; Lee, T. H.; Sim, J. K.

    2013-12-01

    In order to manufacture an eco-friendly stud, the sheared pattern is designed by the Taguchi method and expanded by the side rolls. The seven geometrical shape of sheared pattern are considered in the structural and thermal analyses to select the best functional one in terms of the durability and fire resistance of dry wall. For optimizing the size of the sheared pattern chosen, the L9 orthogonal array and smaller-the-better characteristics of the Taguchi method are used. As the roll gap causes forming defects when the upper-and-lower roll type is adopted for expanding the sheared pattern, the side roll type is introduced. The stress and strain distributions obtained by the FEM simulation of roll-forming processes are utilized for the design of expanding process. The expanding process by side rolls shortens the length of expanding process and minimizes the cost of dies. Furthermore, the stud manufactured by expanding the sheared pattern of the web is an eco-friend because of the scrapless roll-forming process. In addition, compared to the conventionally roll-formed stud, the material cost is lessened about 13.6% and the weight is lightened about 15.5%.

  4. Roll casting of 5182 aluminium alloy

    Directory of Open Access Journals (Sweden)

    T. Haga

    2009-06-01

    Full Text Available Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material.Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed. 5182 could be cast at 10 times higher speed than a conventional twin roll caster for aluminium alloy. 5182 could be cast by the mild steel roll using no-parting material without sticking.Research limitations/implications: is that ability of casting of the wide strip, that is wider than 600 mm, could not be investigated.Practical implications: 600 mm-width 5182 strip could be cast and this width is enough for some structural parts. 5182 could be cast into the strip at high productivity and low energy using the economy equipment and no-consumable good.Originality/value: The method to make economy sheet metal of aluminium alloy is imported. The economy alloy and economy process are essential to get economy aluminium alloy sheet.

  5. New versions of the rolling double cone

    Science.gov (United States)

    Balta, Nuri

    2002-03-01

    Rolling a double cone upward is interesting but oscillating it on a track having an elevated centre is fascinating. You can design three different arrangements of a pair of cones each requiring different tracks to roll up and oscillate on a track of elevated centre.

  6. Effect of Pavement Conditions on Rolling Resistance

    Directory of Open Access Journals (Sweden)

    Mr.Dipanjan Mukherjee

    2014-07-01

    Full Text Available Rolling resistance is the force acting on a vehicle over a full journey. It is generated by the hysteresis of tyre and pavement. Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation (or movement of the wheel, roadbed, etc. is recovered when the pressure is removed. A hysteresis phenomenon can be observed when viscoelastic materials undergo a load-then-unload process. A typical hysteresis curve of viscoelastic material can be found. The shadow area enclosed by the hysteresis loop represents energy loss. A characteristic of a deformable material such that the energy of deformation is greater than the energy of recovery. The rubber compound in a tire exhibits hysteresis. As the tire rotates under the weight of the vehicle, it experiences repeated cycles of deformation and recovery, and it dissipates the hysteresis energy loss as heat. Hysteresis is the main cause of energy loss associated with rolling resistance and is attributed to the viscoelastic characteristics of the rubber. Materials that have a large hysteresis effect, such as rubber, which bounce back slowly, exhibit more rolling resistance than materials with a small hysteresis effect that bounce back more quickly and more completely, such as steel or silica. Low rolling resistance tires typically incorporate silica in place of carbon black in their tread compounds to reduce low-frequency hysteresis without compromising traction. Note that railroads also have hysteresis in the roadbed structure. Like the fuel consumption, rolling resistance also has a significant relationship with velocity. experiment has shown that, for a 32-tonn goods vehicle, rolling resistance contributes about 70% of total drag when driven at 50km/h and about 37% at 100km/h. An important issue which should not be overlooked is that rolling resistance is affected by the characteristics of the pavement surface. Rolling resistance varies between different pavement surfaces. Hard and smooth surfaces produce lower rolling resistance than soft and rough surfaces. Rolling resistance is affected by both tyre and ambient temperature.

  7. How to make a cylinder roll uphill

    CERN Document Server

    Hore, Dipabali; Mondal, Subrata; Roy, Abhijit; Ghatak, Animangsu

    2015-01-01

    Slithering, crawling, slipping, gliding are various modes of limbless locomotion that have been mimicked for micro-manipulation of soft, slender and sessile objects. A lesser known mode is rolling which involves periodic, asymmetric and lateral muscular deformations. Here we enable an elastomeric cylinder of poly(dimethylsiloxane) to roll on a substrate by releasing small quantity of a solvent like chloroform, toluene, hexane, heptane and so on, which swells differentially a portion of the cylinder, but evaporates from portion of it which remains exposed to the atmosphere. In a dynamic situation, this asymmetric swelling-shrinking cycle generates a torque which drives the cylinder to roll. The driving torque is strong enough that the cylinder can roll up an inclined plane, within a range of inclination, its velocity even increases. The cylinder can even drag a dead weight significantly larger, ~8-10 times its own weight. A scaling law is derived for optimizing the rolling velocity.

  8. Surface defects on austenitic rolled steel

    International Nuclear Information System (INIS)

    A study was made on the nature of surface defects of 12Kh2N4A, Kh18N10T, Kh23N18 and other rolled steels, the reasons of their formation and the methods for their prevention. It is shown that main types of surface defects are presented by fissures and cracks. The fissures are related to low metal plasticity, as well as to steel rolling at the temperature lower than recrystallization temperature. The use of differentiated conditions of heating ingots for rolling excludes completely these defects. Cracks are of different nature: the single ones form during rolling on ingots, casted carelessly; the grouped cracks are located along two antipodar rolling generatrices. They are characteristic for intermediate oval profile with low mechanical properties

  9. Automated Procedure for Roll Pass Design

    Science.gov (United States)

    Lambiase, F.; Langella, A.

    2009-04-01

    The aim of this work has been to develop an automatic roll pass design method, capable of minimizing the number of roll passes. The adoption of artificial intelligence technologies, particularly expert systems, and a hybrid model for the surface profile evaluation of rolled bars, has allowed us to model the search for the minimal sequence with a tree path search. This approach permitted a geometrical optimization of roll passes while allowing automation of the roll pass design process. Moreover, the heuristic nature of the inferential engine contributes a great deal toward reducing search time, thus allowing such a system to be employed for industrial purposes. Finally, this new approach was compared with other recently developed automatic systems to validate and measure possible improvements among them.

  10. TR-I rocket roll control system

    Science.gov (United States)

    Kouchiyama, Jiro; Funo, Yasuhiro; Ogawa, Shigeyuki; Fujiwara, Teruo; Nishida, Megumu; Hasegawa, Kazuo

    A test rocket designated as TR-I was launched to acquire engineering design data for H-II, the Japanese next-generation satellite launcher, which has been under development by NASDA. A simple roll control system has been installed to the TR-I in order to maintain roll angle and roll rate within a limitation during the flight for assuring complete downlink of the telemetry system and for simulating flight conditions of the H-II. Major components of the roll control system, such as the Electronics Package (E-PACK), Inertial Sensor Package (ISP), Solid Motor Roll Control Unit (SMRC), and their hardware-in-the-loop (HWIL) simulation are discussed, referring to the actual flight data.

  11. Effect of Warm Rolling on Microstructure and Mechanical Properties of Twin-roll Casted ZK60 Alloy Sheets

    Scientific Electronic Library Online (English)

    Xibing, Gong; Wentao, Gong; Suk Bong, Kang; Jae Hyung, Cho.

    2015-04-01

    Full Text Available In this study, ZK60 magnesium alloy strips were produced by twin roll casting (TRC) and then subjected to warm rolling at the temperature of 300 °C and 350 °C. Rolled sheets related to different rolling reductions were prepared after sequential warm rolling with the rolling speed of 5 m/min. Microst [...] ructures, texture, hardness, tensile properties of the rolled sheets with different rolling reductions were studied experimentally. It has been found that grain refinement occurs actively during the warm rolling. Also, high density of shear bands were observed in the rolled sheets. The warm rolling sheet presents strong (0002) basal texture. In addition, the increase of the rolling reduction results in the improvement of the mechanical properties.

  12. Adapting cable grinding technology to the special demands of nuclear power plant demolition

    International Nuclear Information System (INIS)

    The demolition of nuclear plants is making more and more use of cable grinding because of the specific advantages of this technique. The need for a dry dismantling technology causes vastly faster tool wear because of the lack of a matching tool system. Laboratory studies of cable grinding tools used dry on steel structures indicate that higher cutting speeds give rise to lower process forces and tool temperatures. Tool temperatures of up to 200 C were determined thermographically in tools used at cutting speeds of 11 to 33 m/s in 1.4571-type stainless steel and S 355-type structural steel for rates of metal removal of 0.050 to 0.065 m2/h. Wear at these temperatures especially of the rubber coating of the cables has a very negative impact on the attainable service life of the tools used. Studies in which variation of the feed pressure attained rates of metal removal of up to 0.117 m2/h show that the increased abrasion of material has a proportional impact on the resultant process forces and tool temperatures. However, matched cutting speeds can help reduce the thermal load on cable grinding tools. To remove part of the heat produced in the cable grinding tool in dry processing, on the one hand, and avoid recontamination, on the other hand, a novel cooling system has been developed for the cable grinding process. Laboratory studies conducted with the new cooling system prove its efficiency. Tools whose temperatures in dry working had been determined to be around 140 C can be cooled down by up to 70 C by means of the cooling system. The tool temperatures achieved in this way can be considered uncritical not only for diamonds but, above all, for the rubber coating of the tool as well. (orig.)

  13. Stability and bifurcation analyses of chatter vibrations in a nonlinear cylindrical traverse grinding process

    Science.gov (United States)

    Kim, Pilkee; Jung, Jeehyun; Lee, Sooyoung; Seok, Jongwon

    2013-07-01

    In this study, stability and bifurcation analyses are performed on a cylindrical traverse grinding process in order to investigate its nonlinear chatter behaviors. The grinding model system under consideration appears to be a set of autonomous doubly regenerative delay differential equations. The linear stability boundaries of this grinding system are first evaluated by performing an eigen-analysis on the linearized system. In this stability analysis, a boundness condition for the chatter frequency is obtained and is used to avoid difficulties in identifying the stability boundary caused by the infinite-dimensional nature of the delayed system. The resulting linear stability diagrams are illustrated in the parametric windows of interest. Based on these stability diagrams, bifurcation analyses are conducted by the methods of multiple scales and harmonic balance (MMS and MHB) in order to investigate the local and global chatter behaviors. The criticality of Hopf bifurcation is analytically determined based on the normal form equations of the grinding system through the MMS. Furthermore, the codimension-two bifurcations of equilibrium, such as the Bautin and Hopf-Hopf bifurcations, are also identified in this study. For large-amplitude chatter behaviors, the periodic solutions bifurcated from the critical equilibrium are calculated by the MHB. The cyclic fold bifurcation of the limit cycle is newly identified. In these bifurcation analyses, the nonlinear chatter behaviors of the present grinding system are examined and discussed through the resulting bifurcation diagrams of limit cycles, the Bautin bifurcation diagram, and the corresponding phase portraits. These results are validated by comparison with those obtained through direct numerical integration.

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

    Scientific Electronic Library Online (English)

    Fábio Romano Lofrano, Dotto; Paulo Roberto de, Aguiar; Eduardo Carlos, Bianchi; Rogério Andrade, Flauzino; Gustavo de Oliveira, Castelhano; Landry, Pansanato.

    2003-12-01

    Full Text Available 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 ger [...] al, 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. Abstract in english 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 b [...] e 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.

  15. 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.

  16. Mill’s Liberal Feminism: Its Legacy and Current Criticism

    Directory of Open Access Journals (Sweden)

    MARIANA SZAPUOVÁ

    2006-12-01

    Full Text Available This paper highlights John Stuart Mill’s views on the problem of gender equality as expressed in The Subjection of Women, which is commonly regarded as one of the core texts of Enlightenment liberal feminism of the 19th century. In this paper, the author outlines the historical context of both Mill’s views and his personal biography, which influenced his argumentation for the emancipation of women, and considers Mill’s utilitarianism and liberalism, as the main philosophical background for his criticism of social conditions that subordinated women. She reflects on some of the philosopher’s ideas and arguments for equality and friendship between women and men which may still be considered noteworthy and relevant. Attention is also given to the main lines of contemporary reception of Mill’s liberal feminism from the perspective of current feminist philosophy, within which certain critical views predominate. Despite some problematic points in Mill’s considerations, his essay on women’s subjection may be regarded as one of the philosophically most interesting conceptions of liberal feminist thinking.

  17. Microstructure Engineering in Hot Strip Mills, Part 1 of 2: Integrated mathematical Model

    Energy Technology Data Exchange (ETDEWEB)

    J.K. Brimacombe; I.V. Samaraseker; E.B. Hawbolt; T.R. Meadowcroft; M. Militzer; W.J. Pool; D.Q. Jin

    1998-09-30

    This report describes the work of developing an integrated model used to predict the thermal history, deformation, roll forces, microstructural evaluation and mechanical properties of steel strip in a hot-strip mill. This achievement results from a join research effort that is part of the American Iron and Steel Institute's (AISI) Advanced Process Control Program, a collaboration between the U.S. DOE and fifteen North American steel makers.

  18. 3D finite elements method (FEM) Analysis of basic process parameters in rotary piercing mill

    OpenAIRE

    Z. Pater; J. Bartnicki; J. Kazanecki

    2012-01-01

    In this paper 3D FEM analysis of process parameters and its infl uence in rotary piercing mill is presented. The FEM analyze of the rotary piercing process was made under the conditions of 3D state of strain with taking into consideration the thermal phenomena. The calculations were made with application of different rolls’ skew angles and different plug designs. In the result, progression of shapes, temperature and distributions of stress and strain were characterized. The numerical results ...

  19. Precision grinding for rapid fabrication of segments for extremely large telescopes using the Cranfield BoX

    Science.gov (United States)

    Tonnellier, Xavier; Morantz, Paul; Shore, Paul; Comley, Paul

    2010-07-01

    An ultra precision large optics grinding machine, BoX®, was developed and produced at Cranfield University. BoX® offers a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. Grinding high accuracy surfaces with low subsurface damage reduces subsequent polishing time. This efficient grinding process provides the capacity to grind 1.5 m parts. This paper presents an analysis of Astrositall® optical ground parts: a hexagonal 84 m radius of curvature mirror of 1 m across corners and an off-axis 350 mm diameter mirror. The 1 m hexagonal part is representative of segments under study for making extremely large telescope (ELT) segmented mirrors. The second part was machined off-axis to demonstrate free-form fabrication capability. These operations demonstrate the scalability of the rapid grinding process developed for large free-form optics. The use of an error compensation procedure improved an initial ground form accuracy to +/- 1 ?m p-v over 1 metre surface. The results highlighted the effect of grinding parameters and machine dynamics on form accuracy and fabrication time.

  20. 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)

  1. Moagem de pós de carbeto de silício em moinho planetário / Planetary milling of silicon carbide powders

    Scientific Electronic Library Online (English)

    M. A. P. dos, Santos; C. A., Costa.

    2005-12-01

    Full Text Available Pó de alfa carbeto de silício (alfa-SiC) foi cominuído em moinho planetário durante os períodos de tempo de ½, 2, 4 e 6 h. A velocidade de rotação foi de 300 rpm, o meio de moagem foi álcool isopropílico e os corpos moedores foram esferas de zircônia estabilizada com céria. Os pós cominuídos foram c [...] aracterizados quanto ao tamanho e distribuição de tamanho de partícula, a composição química, as fases cristalinas e a morfologia. Observou-se uma grande redução no tamanho de partículas, que passaram de micrométricas para submicrométricas e até nanométricas, alteração da distribuição das mesmas de bimodal para unimodal, e a geração de aditivação secundária causada pelo meio de moagem. Abstract in english Alpha silicon carbide (alpha-SiC) powder was comminuted in planetary mill during ½, 2, 4 and 6 h. The rotation speed was 300 rpm, the medium of milling was isopropyl alcohol and the grinding bodies were spheres of ceria-stabilized zirconia. The milling powders were characterized concerning the size [...] and particle size distribution, the chemical composition, the crystalline phases, and morphology. A large reduction of the particle size, that had changed from micrometrics to submicrometrics and even nanometrics, a change of their distribution from bimodal to unimodal, and the generation of secondary aditivation caused by medium of milling were observed.

  2. Modeling on the Effect of Coal Loads on Kinetic Energy of Balls for Ball Mills

    Directory of Open Access Journals (Sweden)

    Yan Bai

    2015-07-01

    Full Text Available This paper presents a solution for the detection and control of coal loads that is more accurate and convenient than those currently used. To date, no research has addressed the use of a grinding medium as the controlled parameter. To improve the accuracy of the coal load detection based on the kinetic energy of balls in a tubular ball mill, a Discrete Element Method (DEM model for ball kinematics based on coal loads is proposed. The operating process for a ball mill and the ball motion, as influenced by the coal quality and the coal load, was analyzed carefully. The relationship between the operating efficiency of a coal pulverizing system, coal loads, and the balls’ kinetic energy was obtained. Origin and Matlab were utilized to draw the variation of parameters with increasing coal loads in the projectile and cascading motion states. The parameters include the balls’ real-time kinetic energy, the friction energy consumption, and the mill’s total work. Meanwhile, a method of balanced adjacent degree and a physical experiment were proposed to verify the considerable effect of the balls’ kinetic energy on coal loads. The model and experiment results indicate that a coal load control method based on the balls’ kinetic energy is therefore feasible for the optimized operation of a coal pulverizing system.

  3. Recobrimentos de poli (tereftalato de etileno) depositados em aço por aspersão térmica a partir de pós obtidos em diferentes condições de moagem / Thermally sprayed coated carbon steel produced using PET powder obtained in different grinding conditions

    Scientific Electronic Library Online (English)

    Luciana Tavares, Duarte; Vanessa de Freitas Cunha, Lins; César, Mariano; José Roberto Tavares, Branco; Magno Pinto, Collares; Roberto, Galery.

    2003-07-01

    Full Text Available Neste trabalho foram analisados recobrimentos de poli(tereftalato de etileno), PET, depositados em aço carbono através da técnica de aspersão térmica à combustão, e produzidos a partir de pós oriundos de processos de moagem, em moinho de bolas e de facas, de garrafas de PET pós-consumo. Algumas cond [...] ições de moagem foram testadas, tendo-se obtido pós com diferentes características morfológicas. As características morfológicas dos pós e dos recobrimentos foram avaliadas por microscopia óptica e eletrônica, tendo-se observado que o recobrimento apresentava bolhas, provavelmente devido à degradação do polímero. Além disto, os recobrimentos produzidos, bem como as amostras de pó, foram caracterizados por espectroscopia na região do infravermelho, por calorimetria exploratória diferencial e através da determinação de viscosidade intrínseca em solução. Os resultados obtidos mostraram que é possível a produção de aço carbono recoberto com PET através da técnica de aspersão térmica, sendo que o grau de degradação, a morfologia e a distribuição granulométrica dos pós utilizados influenciaram significativamente as características e propriedades dos recobrimentos formados. Abstract in english The main purpose of this work was to study the production of a thermal spray coated poly(ethyleneterephthalate) steel. Poly(ethylene terephthalate) coatings were made of a thin grinding waste produced by a PET recycling company, and of a PET powder, which was obtained by grinding post-consumer bever [...] age bottles. Some grinding conditions, using a ceramic ball mill, were studied. Scanning Electronic Microscopy (SEM) and optical microscopy (OM) were used in the study of powder and coating morphologies, and this analysis showed that PET coating presents bubbles due to polymer degradation. PET powder and coating characteristics were investigated using Differential Scanning Calorimetry (DSC) and measurements of intrinsic viscosity. It was observed that the powder morphology and the degradation and the size distribution of the PET powder affect significantly the characteristics and properties of coatings.

  4. Recobrimentos de poli (tereftalato de etileno depositados em aço por aspersão térmica a partir de pós obtidos em diferentes condições de moagem Thermally sprayed coated carbon steel produced using PET powder obtained in different grinding conditions

    Directory of Open Access Journals (Sweden)

    Luciana Tavares Duarte

    2003-07-01

    Full Text Available Neste trabalho foram analisados recobrimentos de poli(tereftalato de etileno, PET, depositados em aço carbono através da técnica de aspersão térmica à combustão, e produzidos a partir de pós oriundos de processos de moagem, em moinho de bolas e de facas, de garrafas de PET pós-consumo. Algumas condições de moagem foram testadas, tendo-se obtido pós com diferentes características morfológicas. As características morfológicas dos pós e dos recobrimentos foram avaliadas por microscopia óptica e eletrônica, tendo-se observado que o recobrimento apresentava bolhas, provavelmente devido à degradação do polímero. Além disto, os recobrimentos produzidos, bem como as amostras de pó, foram caracterizados por espectroscopia na região do infravermelho, por calorimetria exploratória diferencial e através da determinação de viscosidade intrínseca em solução. Os resultados obtidos mostraram que é possível a produção de aço carbono recoberto com PET através da técnica de aspersão térmica, sendo que o grau de degradação, a morfologia e a distribuição granulométrica dos pós utilizados influenciaram significativamente as características e propriedades dos recobrimentos formados.The main purpose of this work was to study the production of a thermal spray coated poly(ethyleneterephthalate steel. Poly(ethylene terephthalate coatings were made of a thin grinding waste produced by a PET recycling company, and of a PET powder, which was obtained by grinding post-consumer beverage bottles. Some grinding conditions, using a ceramic ball mill, were studied. Scanning Electronic Microscopy (SEM and optical microscopy (OM were used in the study of powder and coating morphologies, and this analysis showed that PET coating presents bubbles due to polymer degradation. PET powder and coating characteristics were investigated using Differential Scanning Calorimetry (DSC and measurements of intrinsic viscosity. It was observed that the powder morphology and the degradation and the size distribution of the PET powder affect significantly the characteristics and properties of coatings.

  5. Analysis of market possibilities for development of pipe-rolling production on PJSC «Sumy Frunze MNPO»

    Directory of Open Access Journals (Sweden)

    S.M. Illiashenko

    2013-03-01

    Full Text Available The aim of the article. The aim of this article is analysis and evaluation of market opportunities and the potential of innovative development of Public Joint Stock Company Sumy Frunze Machine-Building Science-and-Production Association, concerning to the production and upgrading of cold-rolling of the tubes with the incomplete certainty of the environment.The results of the analysis. The results of the analysis show that in recent years there is the need to increase services for modernization of cold-rolling tubes in markets of foreign countries. Main factors that contribute to the intensive development and growth of the world market for the modernization of cold-rolling tubes are revealed.It is substantiated that 543 rolling mills, which were produced in the countries of the former Soviet republics, have to be modernized. Their total mass is estimated of 4090-10895 tons. Considering the prices of modernization services which are calculated by weight, market capacity in value terms makes $49,08-130,74 million. About 75% of this capacity is the markets of the former Soviet republics.Their tube companies cannot get new mills so they will upgrade existing ones, because of the unstable financial situation.It is revealed that despite the economic crisis, in the market of production of new pipe-rolling mills their sales are growing in China, India, South Korea and Japan. Also growth of sales of the unique specialized pipe-rolling equipment is observed. Potential consumers of new rolling mills concrete enterprises of the foreign and neighboring countries are defined.The comparative analysis of main producers of new rolling mills, and also services in modernization of the available ones is carried out. As the result, their strengths, weaknesses and prospects of development in the market are defined.The authors made the analysis of market opportunities of innovative development ofPJSC Sumy Frunze MNPO in the market of production and modernization of mills of cold rolling of pipes. The analysis was made with consecutive specification of market prospects ofPJSC Sumy Frunze MNPO. Methods of SWOT-analysis, PEST-analysis and SNW-analysis were used. Features formation of the innovative strategy development of PJSC are defined as result of the analysis. They will allow to get the balance between external and internal possibilities of development and to increase chances of PJSC to reach the success.The main external (of direct and indirect action and internal risk factors of the innovative project of production and modernization of cold-rolling pipes are revealed. The quantitative assessment of extent of their influence is executed with the method of expert evaluations. It is established that at this combination of factors the enterprise is in zone of the increased risk, generally because owing to adverse influence of external factors.The assessment of financial stability of innovative project showed its absolute stability and absence of investment risk, generally because of alleged financing of the project only at the expense of own means of PJSC.The identified multiple-factor quantitative assessment of risk allowed establishing value termsof possible losses (for separate stages and for innovative project as a whole at worst-case scenarios. Comparison of possible losses (taking into account probability of their emergence with the expected income of the project and PJSC as a whole testifies about the acceptable size of risk (even for the pessimistic type of behavior of the person making the decision at implementation of the innovative project of production and modernization of cold-rolling of pipes.Detailed analysis of innovative development potential of PJSC (including the analysis of its separate components: market, innovative, production and marketing potentials concerning production and modernization of pipe-rolling camps which testifies about high chances of implementation of the considered innovative project is made.The received results testify about high chances of realization of one of the most perspective di

  6. High speed roll casting of Mg alloy strip by a vertical type twin roll caster

    Directory of Open Access Journals (Sweden)

    H. Watari

    2006-02-01

    Full Text Available Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm with 100 width could be cast continuously. The casting ability became better with increasing content of Al. Roll cast Mg alloy strips could be hot-rolled down to 0.5 mm. AZ31 as-cast strip could be thinner down to 0.5 mm only by three times of hot rolling. Deep drawing was operated with three kinds of Mg alloy at 250°C, and LDR value was larger than 2.0. It was shown that deep drawing of AZ91 alloy for casting was possible.Research limitations/implications: There was tendency that cracks occurred at the center in the thickness direction as Al content increased.Practical implications: Sheet metal forming of magnesium alloy with high content Al can be realized.Originality/value: It was shown that possibility of high speed roll casting of magnesium alloy, and warm deep drawing of roll cast AZ91 strip.

  7. 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 recommended criterion of 0.025 mg/m³ for crystalline silica, requiring further refinement in engineering controls, administrative controls, or the use of respirators. PMID:21058155

  8. Inflation with a constant rate of roll

    Science.gov (United States)

    Motohashi, Hayato; Starobinsky, Alexei A.; Yokoyama, Jun'ichi

    2015-09-01

    We consider an inflationary scenario where the rate of inflaton roll defined by ?phi/H dot phi remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of 'constant-roll' inflation. We find a general exact solution for the inflaton potential required for such inflaton behaviour. In this model, due to non-slow evolution of background, the would-be decaying mode of linear scalar (curvature) perturbations may not be neglected. It can even grow for some values of the model parameter, while the other mode always remains constant. However, this always occurs for unstable solutions which are not attractors for the given potential. The most interesting particular cases of constant-roll inflation remaining viable with the most recent observational data are quadratic hilltop inflation (with cutoff) and natural inflation (with an additional negative cosmological constant). In these cases even-order slow-roll parameters approach non-negligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime.

  9. Method of Maintaining the Required Values of Surface Roughness and Prediction of Technological Conditions for Cold Sheet Rolling

    Directory of Open Access Journals (Sweden)

    Valí?ek J.

    2014-06-01

    Full Text Available The paper is based on results obtained from topography of surfaces of sheets rolled from deep-drawing steel of the type KOHAL grade 697, non-alloy low-carbon structural steel EN 10263-2:2004 and aluminium. The presented results document correctness of the assumption that the rolling force Froll increases with the increasing reduction ?h and the quality of the rolled surface is improved at the simultaneous increasing of strength of rolled sheets and the decreasing of size of structural grains. The experiment was performed on the two-high rolling stand DUO 210 SVa, which enables only non-continuous technology in contrast to the rolling mill with continuous reduction on one sheet in several degrees on rolling trains, in consequence of which the obtained height parameters of the section are in close correlation with the predicted dependence. Contribution of the work consists in the creation of a mathematical model (algorithm for predicting technological parameters of the two-high rolling stand DUO 210 SVa at change of the absolute reduction ?h, for example for a deep-drawing steel of the type KOHAL grade 697 and non-alloy lowcarbon structural steel PN EN 10263-2:2004 and aluminium, and also in the development of a method of calculation applicable to any material being rolled in general, because the authors have found that various materials can be differentiated by a derived analytical criterion IKP. This criterion is a function of ratio between the modulus of elasticity of reference material and that of actually rolled material. The reference material is here deep-drawing steel of the type KOHAL grade 697. Verification was carried out by measuring changes of final surface roughness profile and final strength of rolled sheets of the stated materials in relation to reductions and those were compared with theoretically predicted values. It is possible to identify and predict on the basis of this algorithm an instant state of surface topography in respect to variable technological conditions. On this basis it is then possible to calculate and plot individual main technological parameters.

  10. Rolling process for producing biaxially textured substrates

    Science.gov (United States)

    Goyal, Amit

    2004-05-25

    A method of preparing a biaxially textured article includes the steps of: rolling a metal preform while applying shear force thereto to form as-rolled biaxially textured substrate having an a rotated cube texture wherein a (100) cube face thereof is parallel to a surface of said substrate, and wherein a [100] direction thereof is at an angle of at least 30.degree. relative to the rolling direction; and depositing onto the surface of the biaxially textured substrate at least one epitaxial layer of another material to form a biaxially textured article.

  11. Angular analysis of the cyclic impacting oscillations in a robotic grinding process

    Science.gov (United States)

    Rafieian, Farzad; Girardin, François; Liu, Zhaoheng; Thomas, Marc; Hazel, Bruce

    2014-02-01

    In a robotic machining process, a light-weight cutter or grinder is usually held by an articulated robot arm. Material removal is achieved by the rotating cutting tool while the robot end effector ensures that the tool follows a programmed trajectory in order to work on complex curved surfaces or to access hard-to-reach areas. One typical application of such process is maintenance and repair work on hydropower equipment. This paper presents an experimental study of the dynamic characteristics of material removal in robotic grinding, which is unlike conventional grinding due to the lower structural stiffness of the tool-holder robot. The objective of the study is to explore the cyclic nature of this mechanical operation to provide the basis for future development of better process control strategies. Grinding tasks that minimize the number of iterations to converge to the target surface can be better planned based on a good understanding and modeling of the cyclic material removal mechanism. A single degree of freedom dynamic analysis of the process suggests that material removal is performed through high-frequency impacts that mainly last for only a small fraction of the grinding disk rotation period. To detect these discrete cutting events in practice, a grinder is equipped with a rotary encoder. The encoder's signal is acquired through the angular sampling technique. A running cyclic synchronous average is applied to the speed signal to remove its non-cyclic events. The measured instantaneous rotational frequency clearly indicates the impacting nature of the process and captures the transient response excited by these cyclic impacts. The technique also locates the angular positions of cutting impacts in revolution cycles. It is thus possible to draw conclusions about the cyclic nature of dynamic changes in impact-cutting behavior when grinding with a flexible robot. The dynamics of the impacting regime and transient responses to impact-cutting excitations captured synchronously using the angular sampling technique provide feedback that can be used to regulate the material removal process. The experimental results also make it possible to correlate the energy required to remove a chip of metal through impacting with the measured drop in angular speed during grinding.

  12. A method to determinate the thickness control parameters in cold rolling process through predictive model via neural networks

    Scientific Electronic Library Online (English)

    L. E., Zárate.

    2005-12-01

    Full Text Available The single stand rolling mill governing equation is a non-linear function on several parameters (input thickness, front and back tensions, yield stress and friction coefficient among others). Any alteration in one of them will cause alterations on the rolling load and, consequently, on the outgoing [...] thickness. This paper presents a method to determinate the appropriate adjustment for thickness control considering three possible control parameters: roll gap, front and back tensions. The method uses a predictive model based in the sensitivity equation of the process, where the sensitivity factors are obtained by differentiating a neural network previously trained. The method considers as the best control action the one that demands the smallest adjustment. One of the capital issues in the controller design for rolling systems is the difficulty to measure the final thickness without time delays. The time delay is a consequence of the location of the outgoing thickness sensor that is always placed to some distance to the front of the roll gap. The proposed control system calculates the necessary adjustment based on a predictive model for the output thickness. This model permits to overcome the time delay that exists in such processes and can eliminate the thickness sensor, usually based on X-ray. Simulation results show the viability of the proposed technique.

  13. Uranium-mill appraisal program

    International Nuclear Information System (INIS)

    The results of special team appraisals at NRC-licensed uranium mills in the period May to November 1981 are reported. Since the Three Mile Island accident, NRC management has instituted a program of special team appraisals of radiation protection programs at certain NRC-licensed facilities. These appraisals were designed to identify weaknesses and strengths in NRC-licensed programs, including those areas not covered by explicit regulatory requirements. The regulatory requirements related to occupational radiation protection and environmental monitoring at uranium mills have been extensively upgraded in the past few years. In addition, there was some NRC staff concern with respect to the effectiveness of NRC licensing and inspection programs. In response to this concern and to changes in mill requirements, the NRC staff recommended that team appraisals be conducted at mills to determine the adequacy of mill programs, the effectiveness of the new requirements, and mill management implementation of programs and requirements. This report describes the appraisal scope and methodology as well as summary findings and conclusions. Significant weaknesses identified during the mill appraisals are discussed as well as recommendations for improvements in uranium mill programs and mill licensing and inspection

  14. Transparent conductive film by large area roll-to-roll processing

    International Nuclear Information System (INIS)

    Sputtered indium tin oxide (ITO) coating on polyethylene terephthalate film has been used as the substrate for roll-to-roll fabrication of large area printed electronics devices, but it is expensive and could be cracked when bending, limiting its applications. Transparent conductive (TC) electrode made by roll-to-roll coating of transparent conductive ink on flexible substrate is an alternative, but both the ink material and the control of the coating quality are very crucial. The major challenges are the coating performance, coating uniformity and defect control during roll-to-roll processing. In this paper, we report the chemical synthesis of silver nanowires in preferred shape and size, the surface modification of the Ag nanowires for better dispersion into the commercial Poly(3,4-ethylenedioxythiophene) Poly(styrenesulfonate) (PEDOT:PSS) conductive polymer ink, and the controlled roll-to-roll coating process on flexible polyethylene terephthalate substrate by a one meter web-width roll-to-roll slot die coating system. We obtained high uniformity PEDOT:PSS coating with optical transmission higher than 80% and sheet resistance lower than 100 ?/square, and silver containing coating with sheet resistance below 40 ?/square and maintained optical transmittance. The slot die coating mechanism is investigated and the influencing factors for coating uniformity and defect are defined. The coated transparent conductive film has the same properties as the sputtered ITO and has been used as the TC electrode for printed lighting, whose performance has been proven by standard weathering test for 1000 h. - Highlight: • Controlled synthesis of silver nanowires using trace amount of Cl? ions • Large area roll-to-roll processed transparent conductive (TC) coatings • TC film has light transmission > 80% and sheet resistance < 100 ?/sq. • Silver containing ink achieved better property than conductive polymer ink. • Used as the TC electrode for printed lighting device with proven performance

  15. Transparent conductive film by large area roll-to-roll processing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Linda Y.L., E-mail: ylwu@simtech.a-star.edu.sg [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Kerk, W.T. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Wong, C.C. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2013-10-01

    Sputtered indium tin oxide (ITO) coating on polyethylene terephthalate film has been used as the substrate for roll-to-roll fabrication of large area printed electronics devices, but it is expensive and could be cracked when bending, limiting its applications. Transparent conductive (TC) electrode made by roll-to-roll coating of transparent conductive ink on flexible substrate is an alternative, but both the ink material and the control of the coating quality are very crucial. The major challenges are the coating performance, coating uniformity and defect control during roll-to-roll processing. In this paper, we report the chemical synthesis of silver nanowires in preferred shape and size, the surface modification of the Ag nanowires for better dispersion into the commercial Poly(3,4-ethylenedioxythiophene) Poly(styrenesulfonate) (PEDOT:PSS) conductive polymer ink, and the controlled roll-to-roll coating process on flexible polyethylene terephthalate substrate by a one meter web-width roll-to-roll slot die coating system. We obtained high uniformity PEDOT:PSS coating with optical transmission higher than 80% and sheet resistance lower than 100 ?/square, and silver containing coating with sheet resistance below 40 ?/square and maintained optical transmittance. The slot die coating mechanism is investigated and the influencing factors for coating uniformity and defect are defined. The coated transparent conductive film has the same properties as the sputtered ITO and has been used as the TC electrode for printed lighting, whose performance has been proven by standard weathering test for 1000 h. - Highlight: • Controlled synthesis of silver nanowires using trace amount of Cl{sup ?} ions • Large area roll-to-roll processed transparent conductive (TC) coatings • TC film has light transmission > 80% and sheet resistance < 100 ?/sq. • Silver containing ink achieved better property than conductive polymer ink. • Used as the TC electrode for printed lighting device with proven performance.

  16. Efficiency of a tool-mounted local exhaust ventilation system for controlling dust exposure during metal grinding operations.

    Science.gov (United States)

    Ojima, Jun

    2007-12-01

    In general, control of metal dust from hand-held disk grinders is difficult because such respirable dust tends to disperse in every direction around the grinding wheel and cannot be captured effectively by a conventional exhaust hood. The author described the application of a custom-made tool-mounted local exhaust ventilation (LEV) system attached to a hand-held disk grinder, and by laboratory experiments assessed its effectiveness at dust control. The effectiveness of the LEV for dust control was assessed by determining the respirable dust concentration around the grinding wheel during metal surface grinding with and without the use of the LEV. It was shown that the average respirable grinding dust concentration decreased from 7.73 mg/m(3) with the LEV off to 4.87 mg/m(3) with the LEV on, a mean dust generation reduction of about 37%. PMID:18212477

  17. A new preparation scheme for a difficult-to-float coking coal by column flotation following grinding

    Scientific Electronic Library Online (English)

    Yinfei, Liaoa; Yijun, Caoa; Zhongbo, Hub; Xiuxiang, Taoc.

    2015-02-01

    Full Text Available A new preparation scheme for a difficult-to-float coking coal from the Kailuan Mine, Tangshan, China was investigated. The results showed that grinding followed by column flotation was beneficial for obtaining products with low ash content. The positive effect of grinding on the coal floatability is [...] attributed to the liberation of intergrowths and coal surface improvement. Tests indicated that 10 minutes was the optimum grinding time, and overgrinding resulted in a deterioration in flotation performance. With a grinding time of 10 minutes, conventional flotation had potential to yield a product with around 12.42% ash content and 69.15% combustible recovery. Column flotation can reduce the product ash content to 11.15% and increase combustible recovery to 74.47%. Consistently better flotation results reveal that column flotation is more efficient than conventional flotation for such fines.

  18. Radiometric study of the flow and distribution behaviour in grinding and flotation plants

    International Nuclear Information System (INIS)

    In addition to the technological description of the process the optimization of apparatuses and plants requires a flow diagram on the basis of the residence time distribution of mass flow in grinding and flotation plants. The transport behaviour of the material in cement clinker grinding was studied in plants of semi-technical and full-technical scale (open and closed circuit) with the aid of radiotracers (24Na, 82Br, 198Au) and continuous measurement characteristic data of the diffusion model were used. On the basis of the cell model the mean residence time and the equivalent number of agitation stages were calculated. The relation to technological parameters (apparatus design, material, grain size) is discussed. (author)

  19. Utilization of teflon and aluminum oxide for wheel cleaning in Minimum Quantity Lubrication (MQL) grinding

    Scientific Electronic Library Online (English)

    Bianca Gomes, Barros; Tiago da, Silva; Rubens Chinali, Canarim; Paulo Roberto de, Aguiar; Eduardo Carlos, Bianchi.

    2014-02-01

    Full Text Available Researches concerning cooling-lubrication optimization in grinding have been conducted to contribute to a more sustainable process. An alternative to flood coolant is minimum quantity lubrication (MQL), which spray oil droplets in a compressed air jet. However, problems related to wheel cleaning wer [...] e reported, due to wheel loading by a mixture of chips and oil, resulting in worsening of surface quality. This work aims to evaluate the viability of Teflon and aluminum oxide for wheel cleaning, compared to MQL without cleaning and MQL with cleaning by compressed air, through the following output variables: surface roughness, roundness, wheel wear, grinding power and acoustic emission. Vickers microhardness measurements and optical microscopy were also carried out. The results showed that both materials were efficient in cleaning the wheel, compared to MQL without cleaning, but not as satisfactory as compressed air. Much work is to be done in order to select the right material for wheel cleaning.

  20. Assessment of Plastic Deformation Upon Grinding Using X-Ray Diffraction Profiles

    Directory of Open Access Journals (Sweden)

    Vivek Roy1 , Binayaka Nahak2 , Mohd Zaheer Khan Yusufzai3 , Meghanshu Vashista4

    2013-04-01

    Full Text Available X-ray diffraction (XRD scan profiles of medium carbon steel ground samples were analyzed to assess the grinding induced plastic deformation. Broadening of XRD scan profiles with higher downfeed indicated the possible plastic deformation. XRD scan profiles were studied to measure full width at half maximum (FWHM of profiles for assessment of plastic deformation at various level of downfeed. FWHM analysis revealed that FWHM increases with downfeed owing to plastic deformation. Grain size of deformed layers was also estimated using Scherrer equation to verify the results obtained through FWHM analysis. Grain size was observed to decrease with downfeed due to associated plastic deformation. Assessment of grinding induced plastic deformation using XRD profiles demonstrated the applicability of this new approach for qualitative measurement of surface integrity characteristics like microhardness and surface roughness. Microhardness measurement and surface roughness analysis of ground samples have been undertaken to confirm the results obtained by FWHM study.