WorldWideScience
 
 
1

Fine grinding of coal in a two-stage high-pressure roll mill/ball mill hybrid mode  

Energy Technology Data Exchange (ETDEWEB)

Because of its pronounced tendency to undergo visco-plastic flow, coal ground in the energy-efficient high-pressure roll mill invariably comes out as a briquetted product which must be disintegrated in a conventional type of grinding device such as the ball mill. The aggregates comprise comminuted coal particles that are apparently extensively cracked and weakened during passage of the coal through the high-pressure rolls. Their desegregation in a ball mill in the second stage is accompanied by further grinding of the coal with a relatively small expenditure of energy. Thus in spite of energy dissipation in briquetting in the roll mill and in disintegrating the briquettes in the ball mill, significant energy savings are possible in the fine grinding of coal in a two-stage serial grinding mode, as compared to ball mill grinding stages must be apportioned in a n optimal manner; the energy consumption in the ball milling step is comparable to, even in excess of, the energy spent in the high-pressure roll mill; and 20 to 50 percent energy savings might be possible grinding coal to minus 200-mesh size by this two-step process, as compared to conventional milling.

Fuerstenau, D.W.; De, A.; Diao, J.; Kapur, P.C. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

1995-10-01

2

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal  

Energy Technology Data Exchange (ETDEWEB)

The objective of the research is the development of improved technology for the preparation of coal-water slurries, which have potential for replacing fuel oil in direct combustion. The fine grinding of coal is a crucial step in the manufacture of coal-water slurries. In this context, currently available grinding mills exhibit poor energy efficiency for size reduction and non-optimum packing characteristics of the ground coal. The first increases the cost of manufacture of coal-water slurries and the second adversely affects their rheological properties. The newly invented choke-fed, high-pressure roll mill is up to 50% more energy efficient and, moreover, there are reasons to believe that it produces a size distribution of ground particles which is closer to the dense packing composition. The high-pressure roll mill (which is perhaps the only really significant innovation in industrial comminution in this century) has lower capital cost, occupies less floor space, shows negligible wear rate, accepts feed with a wide range of moisture contents and, of particular importance, it can be scaled up to grind hundreds of tons of solids per hour. The high-pressure roll mill provides a unique opportunity to develop an improved technology for preparing coal-water slurries. Our research group in the University of California at Berkeley not only has a fully instrumented, laboratory-scale, choke-fed. high-pressure roll mill (the only one of its kind in the United States) but also fully instrumented laboratory ball mills for comparative fine coal preparation purposes. In this research program, our plans are to systematically investigate comminution energy consumption, deagglomeration procedures, and the stability and rheology of coal-water slurry fuel prepared with high-pressure roll mill, and to compare the results with slurry prepared with ball-milled coal.

Fuerstenau, D.W.

1992-12-01

3

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report No. 1, September 1--November 30, 1992  

Energy Technology Data Exchange (ETDEWEB)

The objective of the research is the development of improved technology for the preparation of coal-water slurries, which have potential for replacing fuel oil in direct combustion. The fine grinding of coal is a crucial step in the manufacture of coal-water slurries. In this context, currently available grinding mills exhibit poor energy efficiency for size reduction and non-optimum packing characteristics of the ground coal. The first increases the cost of manufacture of coal-water slurries and the second adversely affects their rheological properties. The newly invented choke-fed, high-pressure roll mill is up to 50% more energy efficient and, moreover, there are reasons to believe that it produces a size distribution of ground particles which is closer to the dense packing composition. The high-pressure roll mill (which is perhaps the only really significant innovation in industrial comminution in this century) has lower capital cost, occupies less floor space, shows negligible wear rate, accepts feed with a wide range of moisture contents and, of particular importance, it can be scaled up to grind hundreds of tons of solids per hour. The high-pressure roll mill provides a unique opportunity to develop an improved technology for preparing coal-water slurries. Our research group in the University of California at Berkeley not only has a fully instrumented, laboratory-scale, choke-fed. high-pressure roll mill (the only one of its kind in the United States) but also fully instrumented laboratory ball mills for comparative fine coal preparation purposes. In this research program, our plans are to systematically investigate comminution energy consumption, deagglomeration procedures, and the stability and rheology of coal-water slurry fuel prepared with high-pressure roll mill, and to compare the results with slurry prepared with ball-milled coal.

Fuerstenau, D.W.

1992-12-01

4

The implementation of HPGR mills in existing grinding circuits  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1996-12-31

5

Electric grinding scab mill  

UK PubMed Central (United Kingdom)

The utility model discloses an electric scab milling machine, which comprises a hollow handle, a motor, a gear cutter blade and a notch cover. The motor comprises a motor shaft and a motor casing, the front end of the motor casing is in screwed connection with the rear end of the notch cover, the motor shaft passes through the side wall of the notch cover, the gear cutter blade is installed on the motor shaft, the front end of the handle is fixed wit the top end of the notch cover, and the rear end of the handle is fixed with the motor casing. By using the electric scab milling machine, an operator can well control the milling depth and monitor the milling surface in time, and the active tissues are protected maximally from being damaged on the premise of ensuring removal of all scabs formed of necrotic tissues, which is in favor of wound surface repair. In addition, the electric scab milling machine is provided with a speed controller, so that the rotation speed of the motor can be regulated in accordance with the scabbing degree of a patient, resulting in convenient and flexible use.

XIANGDONG WANG

6

Cost optimization of stirred ball mill grinding  

Energy Technology Data Exchange (ETDEWEB)

On going research at the University of Alabama has shown that stirred ball mill grinding is the highest cost unit operation in the beneficiation of Eastern Oil Shales. Minimization of that cost is critical if oils derived by beneficiation and hydroretorting of Eastern shales are to become an economic alternative to conventional crude oils. Cost optimization of stirred ball milling is a substantially different problem than optimizing a conventional (tumbling) mill operation. For conventional mills minimum cost is virtually synonymous with minimum energy consumption. Because the technology is mature and well understood, the operator can predictably optimize within a very narrow range of operating conditions. In contrast, stirred ball milling offers the operator several more ``degrees of freedom`` in selecting operating conditions. An example is the selection of rotor speed. In general, lower speeds result in lower energy consumption per ton of material ground but at the cost of reduced mill capacity per unit volume. Because stirred ball mills have a high capital cost per unit volume the trade off between energy consumption and capacity becomes critical. This paper presents a generalized total cost mode for stirred ball milling and examines data generated in the grinding of oil shales in terms of the model. The paper also discuss the role of the cost model in guiding future research in grinding circuit optimization.

Schultz, C.W.; Mehta, R.K. [Alabama Univ., University, AL (United States). Mineral Resources Inst.

1991-12-31

7

Cost optimization of stirred ball mill grinding  

Energy Technology Data Exchange (ETDEWEB)

On going research at the University of Alabama has shown that stirred ball mill grinding is the highest cost unit operation in the beneficiation of Eastern Oil Shales. Minimization of that cost is critical if oils derived by beneficiation and hydroretorting of Eastern shales are to become an economic alternative to conventional crude oils. Cost optimization of stirred ball milling is a substantially different problem than optimizing a conventional (tumbling) mill operation. For conventional mills minimum cost is virtually synonymous with minimum energy consumption. Because the technology is mature and well understood, the operator can predictably optimize within a very narrow range of operating conditions. In contrast, stirred ball milling offers the operator several more degrees of freedom'' in selecting operating conditions. An example is the selection of rotor speed. In general, lower speeds result in lower energy consumption per ton of material ground but at the cost of reduced mill capacity per unit volume. Because stirred ball mills have a high capital cost per unit volume the trade off between energy consumption and capacity becomes critical. This paper presents a generalized total cost mode for stirred ball milling and examines data generated in the grinding of oil shales in terms of the model. The paper also discuss the role of the cost model in guiding future research in grinding circuit optimization.

Schultz, C.W.; Mehta, R.K. (Alabama Univ., University, AL (United States). Mineral Resources Inst.)

1991-01-01

8

Calculating the grinding productivity of medium-speed roller mills  

Energy Technology Data Exchange (ETDEWEB)

The use of medium-speed roller mills for pulverizing coal is described. Some of the problems encountered in the operation of these mills are discussed. Formulas are proposed for determining the grinding output of these mills in actual operation and also for determining optimal and economical ventilation in order to attain such productivity. It was found that the operating period of medium-speed mills increases with size. Thus, large mills are more profitable than small ones.

Shalaev, N.B.; Shteinberg, A.M.

1982-12-01

9

Grinding of coal-oil slurries with the Szego mill  

Energy Technology Data Exchange (ETDEWEB)

In this paper a first systematic set of results on grinding coal in oil with the novel Szego mill is presented and is a contribution to the general knowledge of wet grinding in non- aqueous media. Grinding of coal in fuel oil for coal-oil mixtures (COM) preparation is simpler and may give better slurry properties than dry grinding followed by dispersion in oil. A 42 weight percent slurry of 600-840 micrometer particles of Pittsburgh coal in No.2, 4, and 6 fuel oils has been ground with the novel Szego mill. Particle size distributions at different residence times are reported down to a 10 micrometer median size, together with energy consumption data. Low mill hold-ups and high rotational speeds enhanced the rate of grinding. 9 references.

Papachristodoulou, G.; Trass, O.

1985-02-01

10

Residence time distribution in a vibrating grinding mill  

Energy Technology Data Exchange (ETDEWEB)

In order to determine the values that are characteristic of the continuous conveying process within a vibration grinding mill measurements of the residence time by radioactive marking using Au-198 have been carried out. For evaluating the results the dispersion model was made use of. When grinding an organic product in a Palla-50-U-vibration mill, with or without retaining weir, the volumetric grinding stock filling ratio was found to range between 30 and 35 per cent for the different test runs. The calculated dispersion coefficients range between 200 and 300 cm/sup 2//min and are proportional to the axial velocity of transport.

Ulrich, M.

1981-02-01

11

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical report No. 7, March 1, 1994--May 31, 1994  

Energy Technology Data Exchange (ETDEWEB)

The objective of this research is the development of improved technology for the preparation of coal-water slurries that have potential for replacing fuel oil in direct combustion. This should be of major importance to the United States in its efforts to reduce dependence on imported oil and to rely more on its enormous low-cost coal resources. According to this objective, Quarterly Report No. 1 presented preliminary results on the rheological behavior of coal-water slurries prepared from Pittsburgh No. 8 coal that had been ground in a ball mill under various conditions. Quarterly Report No. 2 summarized the results of studies on the effects of solids content and water immobilization on the rheological behavior of coal-water slurries, including the role of different viscometers, such as the Haake Rotovisco RV-12 and Brookfield Synchro-Lectric LVT on the measured results. In Quarterly Report No. 3, the authors compared the rheological behavior of Pittsburgh No. 8 coal-water slurries using different sensor system. In Quarterly Report No. 4, studies on the role of the initial mixing procedure in the preparation of coal-water slurries were summarized. In Quarterly Report No. 5, the evaluation of the effect of a cationic surfactant (TMAE) and an anionic surfactant (2-TEPA) on the rheological behavior and the aggregative stability of Pittsburgh No. 8 coal-water slurries was presented. In Quarterly Report No. 6, the effect of nonionic surfactants (Triton X series) on the aggregative stability of coal-water slurries was studied by measuring the relative sedimentation volume and floc size distribution.

Fuerstenau, D.W.

1994-06-01

12

Research on roll wear of 2050mm hot strip finishing train (CVC Mill) of Baosteel  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the general characteristics and affecting factors of work and backup rolls wear of finishing train were analyzed. Taking the CVC finishing mills of 2050mm hot strip mill of Baosteel as an example, the roll wear magnitude and contour were calculated in theory, and measured by the present grinding machine in experiment. The calculated results agree well with the measured data in distribution, and also in general characteristics. Based on the calculated and measured results, an on-line prediction model by which the roll wear distribution characteristics of a CVC mill can be revealed more accurately was proposed. (author)

Huang, C.Q.; Yuan, J.G. [Hot Strip Mill Department, Shanghai Baosteel Group, Baoshan District, Shanghai (China); Lian, J.C. [Yuanshan Univ., Qinhuangdao City, Hebei Province (China)

2000-07-01

13

Research on roll wear of 2050mm hot strip finishing train (CVC Mill) of Baosteel  

International Nuclear Information System (INIS)

In this paper, the general characteristics and affecting factors of work and backup rolls wear of finishing train were analyzed. Taking the CVC finishing mills of 2050mm hot strip mill of Baosteel as an example, the roll wear magnitude and contour were calculated in theory, and measured by the present grinding machine in experiment. The calculated results agree well with the measured data in distribution, and also in general characteristics. Based on the calculated and measured results, an on-line prediction model by which the roll wear distribution characteristics of a CVC mill can be revealed more accurately was proposed. (author)

2000-01-01

14

Wet grinding of coal in the Szego Mill  

Energy Technology Data Exchange (ETDEWEB)

New results from a systematic grinding study with the larger, SM 320 Szego Mill are reported. A wide range of flow rates, from 750 to 5300 kg/h of coal, at 60-65% solids concentration has been covered, with both single and multiple passes through the mill. Particle size distributions and power consumption have been measured. Data have been correlated in terms of the mass fraction of particles passing various mesh sizes 45{mu}m and up, also for the required energy consumption. Comparison with results from smaller mills and with scale-up criteria has been made. A dynamic wet-grinding model recently developed for the Szego Mill is reviewed. Use of this model will allow a priori predictions of limiting performance for all design and operating variables in the {open_quotes}past grinding{close_quotes} regime, i.e., at relatively high solids concentrations, optimal for wet grinding in the Szego Mill. Detailed comparisons with model predictions are yet to be made.

Gandolfi, E.A.J.; Leszczyniecki, R.; Trass, O. [Univ. of Toronto, Ontario (Canada)

1993-12-31

15

Latest technologies for process control in hot rolling mill; Netsukanatsuen miru ni okeru saishin no purosesu seigyo gijutsu  

Energy Technology Data Exchange (ETDEWEB)

The most recently developed control technologies in a hot strip mill are described. Preview AGC has been developed with a preview control synthesis. It controls roll gaps by using the previous information of disturbances. The disturbances which are concerned are derived from the rolling force, the roll gap and the thickness of a previous stand. The thickness accuracy and the availability of mill have been improved by this technology. An on-line roll grinding (ORG) system with an on-line roll profile meter (OPM) has been developed for the purpose of achieving schedule-free rolling. The ORG smooths the worn and roughed surface of a work roll and OPM can measure the profile of a revolving roll without contact. The data obtained by the OPM are given as feedback information to the ORG. As a result, grinding accuracy has been improved and rolling restriction on width has been relaxed widely. (author)

Urano, A.; Okada, M. [Kawasaki Steel Corporation, Tokyo (Japan). Mizushima Works; Yanagino, K. [Kawasaki Steel Corporation, Tokyo (Japan). Chiba Works

1999-12-01

16

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

2006-02-15

17

Evaluation of Recycle Grinding Performance in Flour Milling  

Science.gov (United States)

A typical flour milling process is a very linear operation that is almost entirely void of recycled streams where separate fractions from each operation go ahead as new streams to the next operation. In some cases, there are opportunities for combining some streams, for recycling particles that have been insufficiently broken to go back to the same roller mill. This study introduces this recycle concept in flour milling process at second break system. The recycle grinding assessment was made using a Satake STR-100 test roller mill. The recycle process was started after the second break system and the number of recycle grinding was up to 7 regrinds. The particle size distribution and ash analysis were produced to describe the behaviour of the recycle grinding performance. The material release was sifted on a range of sieves and the ash content was analysed using a laboratory furnace. The performance for each recycle stage was investigated. It was determined that it is possible for some coarse particles that contain only bran to keep being recycled in the recycle circuit. A purging operation was recommended to be included in the recycle system, to separate the unwanted particles.

Mazlina Mustapa Kamal, Siti; Webb, Colin

18

Grinding process within vertical roller mills: experiment and simulation  

Energy Technology Data Exchange (ETDEWEB)

Based on screening analysis, laser size analysis, grindability and rigidity tests of samples collected on line from a cement and a power plant, a simulation of the grinding process in vertical roller mills was carried out. The simulation calculation used a breakage function, B. The results indicate that the breakage function, B, and the selection function, S, in the form of a matrix, can be used to express the probability of the material breaking during the grinding process. This allows the size distribution of the product to be numerically estimated. The simulation results also show that the simulated size distribution curves fit the actual experimental product curves quite well. The model provides a good starting point for simulation of the grinding process. Further research is needed to determine the proper breakage function and the matrix value of the selection function. 7 refs., 3 figs., 6 tabs.

Jian-huai Wang; Qing-ru Chen; Ya-li Kuang; A.J. Lynch; Jin-wu Zhuo [China University of Mining & Technology, Xuzhou (China). School of Chemical Engineering and Technology

2009-01-15

19

[Dehulling of sorghum in grinding mills  

UK PubMed Central (United Kingdom)

The efficiency of the dehulling process of sorghum grain was studied in a laboratory abrasive stone mill. Residual tannins as tannic acid and cathequin equivalent, as well as color measurements of the product were determined as control parameters of the procedure. Besides, fiber, ash and fat contents as well as other variables were evaluated. Assays were performed at three stone speeds and at different operation times. According to the results obtained, a stone speed of 1,700 rpm and a 12-minute period, are the best operating conditions, while measurements of color of the product constitute the best method for controlling the dehulling process.

Corimayo JR; Gutiérrez RR; Gómez MH

1986-12-01

20

WIPER BLADE FOR A ROLLING MILL  

UK PubMed Central (United Kingdom)

The invention relates to a wiper blade system for wiping a product from a roller in a rolling mill, particularly at the last roller in a five-roller mill, comprising a cutter bar, a cutter holder, and a wiper blade (1), which rests against the roller comprising the product to be wiped off. The cutter holder has a spring-loaded blade clamping system.

HOEHENER MANUEL

 
 
 
 
21

Cost effectiveness of automatic ultrasonics in mill roll testing  

Energy Technology Data Exchange (ETDEWEB)

Roll inspection is necessary to ensure that rolls being returned to the mill are free from defects that may cause the premature failure of the roll, whilst in service. This paper describes the use of an Automatic Ultrasonic system for the inspection of Caster Rolls, up to 140 in. long and 30 in. diameter and its benefits to the user. Roll inspection has been found to be paramount in today`s quality and cost conscious mill operations. Inspection leads to: (1) improved product quality; (2) reduced mill down time; (3) improved roll life; and (4) reduced plant operating costs.

Willcox, M. [DeW Systems Ltd., Hereford (United Kingdom)

1996-12-31

22

Kinetics of wet versus dry grinding of lignite by a porcelain mill  

Energy Technology Data Exchange (ETDEWEB)

The kinetics of dry versus wet grinding of several feed size fractions of lignite in a laboratory size porcelain mill are reported using feed fractions prepared to 600+425, -425+300 and -300+212 {mu}m mono-sizes. The kinetics process is first-order up to 8 min for dry grinding while it is first-order up to 16 min for wet grinding. However, the specific rates of breakages decrease as feed sizes decrease for both dry and wet grinding. The breakage parameters, indicate that wet grinding in a porcelain ball mill is more efficient to get finer product sizes. The simulated product size distributions of both dry and wet grinding are in good agreement with the experimental product size distributions using a standard ball mill simulation program.

Ozkan, A.; Yekeler, M. [Cumhuriyet University, Sivas (Turkey). Dept. of Mining Engineering

2002-06-01

23

Dissemination of diesel grinding mill battery charging system  

Energy Technology Data Exchange (ETDEWEB)

This research project concerned the development of a cost-effective scheme which enabled domestic consumers to use electricity, for lighting and radio from small mobile 12V batteries which could be readily transported to the local maize grinding mill for recharging as required. System users unanimously commented on the benefits for themselves and the community. The light provided was better quality than from traditional sources and clearly improved living and working standards. Users in domestic households, where the light is usually situated in the living room, commented on better conditions for children's schoolwork, reading and sewing. School teachers found that improved lighting assisted their workload and bottle/store owners found that the appearance of their premises had a positive effect on business operations. (author)

NONE

1998-07-01

24

Novel tube-rolling process using the 3-roll planetary mill (PSW)  

Energy Technology Data Exchange (ETDEWEB)

A high-reduction, 3-roll planetary mill for the production of seamless tube is described and compared with conventional methods. Advantages include continuous rolling, close wall tolerance, increased yield and energy savings.

Bretschneider, E.J.F.E.

1981-10-01

25

Saving of Electrical Energy by the Use of Vertical Roller Mills for Cement Grinding. Final Report.  

Science.gov (United States)

As the grinding of cement in ball mills is not energy efficient, a procedure was tried by grinding in a bed of material for greater efficiency. This is the report of the initial tests, the optimising for various sorts of cements and the following three ye...

E. A. Kaemmerer

1986-01-01

26

Modified oil agglomeration process for coal beneficiation. III. grinding and agglomeration using different Szego mill designs  

Energy Technology Data Exchange (ETDEWEB)

The purpose is to describe experiment tests using the Szego mill to beneficiate Minto coal by the simultaneous grinding and agglomeration process. Tests were run with different roller ridge/groove sizes on the mill, which is a planetary ring roller mill with grooved rollers, and good results were obtained. Favourable oil-coal-water ratios were established. Ash removal depends on grinding performance. Very short mill residence times (about 10 seconds) are sufficient for microagglomerate formation. Considerable equipment and operating cost savings are possible with the modified process. 11 refs., 7 figs.

McCracken, T.W.; Trass, O. (National Research Council, Ottawa, ON (Canada). Institute for Environmental Chemistry)

1994-04-01

27

Analysis of roll stack deflection in a hot strip mill  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Predictive models are required to provide the bending set point for bending for the flatness control devices at rolling stands of finishing mill of Hot Strip Mill (HSM). A simple model for roll stack deflection at the finishing mill has been illustrated where a modified Misaka?s equation has been used to obtain mean flow-stress. Investigation has been performed to understand the effect of width of roll on roll stack deflection. The bending on the deflection has been foun (more) d to have a positive effect to reduce the amount of the stack deflection. The results from the sensitivity analysis of the roll width on roll deflection are also described.

Sikdar, Sudipta; John, Shylu; Pandit, Ashwin; Dasu, Raju

2007-09-01

28

Analysis of roll stack deflection in a hot strip mill  

Directory of Open Access Journals (Sweden)

Full Text Available Predictive models are required to provide the bending set point for bending for the flatness control devices at rolling stands of finishing mill of Hot Strip Mill (HSM). A simple model for roll stack deflection at the finishing mill has been illustrated where a modified Misaka’s equation has been used to obtain mean flow-stress. Investigation has been performed to understand the effect of width of roll on roll stack deflection. The bending on the deflection has been found to have a positive effect to reduce the amount of the stack deflection. The results from the sensitivity analysis of the roll width on roll deflection are also described.

Sudipta Sikdar; Shylu John; Ashwin Pandit; Raju Dasu

2007-01-01

29

Structural causes of defects in a cast iron mill roll  

Directory of Open Access Journals (Sweden)

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.

J. Krawczyk

2008-01-01

30

[Occupational skin diseases in rolling-mill workers in aluminum mills  

UK PubMed Central (United Kingdom)

Some data on frequency and nature of occupational dermatological diseases and stigmata, as well as the results of epicutaneous allergy tests done with occupational allergens with 234 rollers in the rolling mills of the aluminum mill in Razine, near Sibenik are presented. We have recorded occupational dermatose in 44 rollers (18.8%). In the hot rolling mill, sixty rollers have undergone the test and there was 16 recorded cases of occupational dermatose (26.6%). In the cold rolling mill, 174 rollers have undergone the test, and the occupational dematose was recorded in 28 rollers (16.1%). Positive epicutaneous allergic reaction on occupational allergens was found in 5 (2.1%) rollers. Occupational stigmata are somewhat more frequent in the hot rolling mill and their ratio is from 48-100%, whereas in the cold rolling mill they are somewhat less frequent ranging between 40.3 and 97.0% of rollers.

Bali? J; Klarica J

1989-04-01

31

Radiotracer Investigation of Clinker Grinding Mills for Cement Production at Ghacem  

Directory of Open Access Journals (Sweden)

Full Text Available 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 the milling and separator sections of both mills were the same. It was also observed from the estimated mill efficiencies that mill 4 operated with optimal performance while the efficiency of mill 3 was far below the expected value.

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

32

Wet grinding of coal in the Szego Mill: limiting predictions and experimental results  

Energy Technology Data Exchange (ETDEWEB)

Coal was systematically ground with an SM-320 Szego Mill using a wide range of flow rates, and single and multiple passes through the mill. Particle size distribution and power consumption were measured, and the data correlated with particle size. A wet grinding model for this mill was also reviewed. This predicts optimal performance at relatively high solids concentrations. Observations and predictions conformed. 12 refs., 15 figs.

Trass, O.; Papachristodoulou, G.L.; Gandolfi, E.A.J. [University of Toronto, Toronto, ON (Canada). Dept. of Chemical Engineering and Applied Chemistry

1995-12-31

33

Recent technical developments in rolling mill rolls. Atsuen roru ni kansuru saikin no gijutsu doko  

Energy Technology Data Exchange (ETDEWEB)

To meet recent rapid advances in rolling technology, there have been increasing needs for high-performance rolls with longer life and higher reliability. In the field of rolling mill rolls, corresponding to these rolling needs, not only the improvement of existing materials such as high-alloy grain cast iron, etc., but also the development and application of new material rolls such as high-chromium system and tool steel system (high speed steel) have been conducted. Also, in manufacturing processes, in addition to the conventional centrifugal casting process, etc., special manufacturing processes such as the continuous pouring process for cladding (CPC) and the hot isostatic pressing (HIP) process and so forth are adopted. Accordingly, In this report, the transitions and current status of rolling mill rolls' materials were outlined for respective rolling mills in the first half section and the features, operating conditions, etc., of newly developed rolls either in the material or in the manufacturing process which have excellent performance were described in the second half section, centering around those of the rolls developed by Nippon Steel Corp., Plant and Machinery Division. 35 refs., 5 figs., 3 tabs.

Hashimoto, M.; Ishibashi, S.; Kawai, T.; Iboshi, S.; Ayagaki, M.; Kimura, K.; Yamamoto, Y. (Nippon Steel Corp., Tokyo (Japan))

1992-11-30

34

Floc flotation of Prince coal with simultaneous grinding and hydrophobic flocculation in a Szego mill  

Energy Technology Data Exchange (ETDEWEB)

The beneficiation of ultrafine coal has been studied using a method combining fine grinding and selective hydrophobic flocculation in a Szego mill. In this simultaneous grinding and hydrophobic flocculation-flotation (SGHFF) process, the excess mechanical energy expended in grinding is utilized for mixing coal slurry, resulting in the formation of hydrophobic coal flocs in the mill. The SGHFF process was tested for removing ash and pyritic sulfur from Prince coal. After four-stage cleaning flotation, 92.8% of ash and 65.8% of pyrite were rejected from the coal with 81.6% combustible recovery. The size of the flocs formed in the Szego mill was determined, and the main factors affecting the SGHFF process were also investigated. Compared with the HFF system, the SGHFF system seems economically advantageous, owing to savings in equipment and power consumption. 19 refs., 4 figs., 4 tabs.

Song, S.; Trass, O. [Universidad Autonoma de San Luis Potosi, San Luis Potosi (Mexico). Inst. de Metallurgica

1997-07-01

35

Analysis of grinding actions of ball mills by discrete element method  

Energy Technology Data Exchange (ETDEWEB)

Application of the discrete element method incorporating the simple kinetic model of the ball-to-ball and ball-to-wall interactions enables one to visualize the details of the grinding actions prevailing in the ball mills. The authors have developed a computer program to represent a generic mill model with which they can simulate tumbling mills, vibration mills, centrifugal mills and planetary mills. While the program can be used for various purposes including design of new equipment, one obvious application of it is the analysis of the conventional tumbling ball mills for better understanding and improvement. The purpose of this paper is to present a model and to observe its behavior with particular attention paid to the spatial distribution of the energy dissipation as well as the energy spectrum and their dependence on the major parameters such as mill speed, ball filling, liner configuration, slurry viscosity and the hardness of the ore.

Inoue, Toshio; Okaya, Katsunori

1995-12-31

36

Performance of the Szego mill in dry grinding coal and wheat  

Energy Technology Data Exchange (ETDEWEB)

An analysis of the novel, planetary ring-roller Szego mill and its performance in dry grinding of coal and wheat is presented for open-circuit operation. The independent variables were the rotational speed of the mill, feed size and feed rate. Their effects on the dependent variables of product size distribution, power consumption and mean residence time are reported. The feed size was found not to affect the product size distribution.

Gotsis, C.; Trass, O.

1985-03-01

37

Statistical model and control of a ring-and-roller type grinding mill  

Energy Technology Data Exchange (ETDEWEB)

This project explores the use of a ring-and-roller grinding mill for fine grinding or pulverizing. Since the efficiency of this system is low, small improvements in product throughput or energy consumption can result in substantial economic improvements. To better understand this system, experiments were conducted for limestone and cement clinker. From these experiments models were formulated for product throughput, energy consumption and product size distribution. A control loop was implemented to reduce the effect of non-uniform feeding. Steady-state interactions were analyzed using the Relative Gain Array (RGA) method. Next, a multi-input and multi-output (MIMO) control system was designed using the Inverse Nyquist Array (INA) method to remove variable interactions. The robustness of this controller was explored. Finally, a self-tuning PI controller was designed using the pole placement method to improve system performance. The results of this study provide models for implementation on ring-and-roller grinding mills.

Cho, S.

1992-01-01

38

Evaluation of Recycle Grinding Performance in Flour Milling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A typical flour milling process is a very linear operation that is almost entirely void of recycled streams where separate fractions from each operation go ahead as new streams to the next operation. In some cases, there are opportunities for combining some streams, for recycling particles that have...

Siti Mazlina Mustapa Kamal; Colin Webb

39

Energy-saving ultra-fine grinding with the SALA Agitated Mill. Energiesparende Feinstmahlung mit der SALA-Agitated-Mill  

Energy Technology Data Exchange (ETDEWEB)

The SALA Agitated Mill (SAM) from Allis Mineral Systems GmbH, Bad Vilbel, produces power savings of 25 to 50% in ultra-fine comminution when compared with the traditional tube mill. It also lowers the capital costs because, due to an internal classifying action, it is usually possible to dispense with an external classifier circuit. The use of tungsten carbide for the stirrer minimizes the wear costs. The SALA Agitated Mill is used for wet and dry grinding of intermediate products in the mineral, primary, and cement industries, in the chemical industry and in the manufacture of pigments. Agitated or stirrer ball mills have been used for years for fine and ultra-fine comminution of coloured pigments, ceramic materials and also in foodstuffs technology and chemistry. So far any application in the mineral and primary industries has usually foundered on the problems of wear and low throughputs, and sometimes also on difficulties in the process engineering design. (orig.)

Anon.

1993-09-01

40

Dimensional ranges and rolling efficiency in a tandem cold rolling mill  

Energy Technology Data Exchange (ETDEWEB)

In this work, physical models and a neural network theory have been combined in order to predict the properties of a steel strip and to optimise the process parameters in cold rolling. The prediction of the deformation resistance of the material and the friction parameter is based on the physical model presented by Bland, Ford and Ellis and artificial neural network computing (ANN). The accuracy of these models has been tested and proved by using a large amount of the measured data. With the aid of these models it has been shown that (a) the small change to the relative reduction distribution can have a clear effect upon the rolling efficiency, (b) the dimensional ranges of the tandem cold roll mill can be determined and optimised and (c) the possibility to cold roll a new product of new width, strength or thickness can be determined and the parameters of the tandem cold rolling process can be optimised. (orig.) 43 refs.

Larkiola, J.

1997-12-31

 
 
 
 
41

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 (SN), stress energy (SE) and the specific energy (Em,p). The visualisation of the particles at different stages of milling is done by scanning electron microscope (SEM). The results show that finer particles are produced by increasing milling duration from 0 – 240 min due to an increase in SN and that the use of smaller grinding media inside the mill produced finer particles due to an efficient consumption of Em,p.

Stephen Adegbite

2012-01-01

42

Characterization of round@flat bar and wire rolling by 2-roll and 3-roll mills. 1. ; Application of computational rolling mill. Round@flat 2 roll oyobi 3 roll hoshiki ni yoru boter dot senzai atsuen no henkater dot fuka tokusei. 1. ; Suchi atsuenki no oyo gijutsu ni kansuru kenkyu  

Energy Technology Data Exchange (ETDEWEB)

Analyses were given on round{approximately} flat bar and wire rolling by 2-roll and 3-roll mills using the computational rolling mill CORMILL system based on the three-dimensional rigid-plastic FEM, and a description is given on the difference of plastic deformation characteristics caused from the rolling of both types of mill. The result obtained from setting the exclusion sectional area ratio (ratio of sectional area excluded by the roll to the initial sectional area of rolled material) in four levels from 10% to 40% may be summarized as follows: (i) A 3-roll mill can roll a material at higher rolling efficiency with lower rolling load than a 2-roll mill can; (ii) a 3-roll mill generates smaller equivalent strain (strain when an extinction rate is identical) after a material is rolled than a 2-roll mill does, and causes a region with small equivalent strain to appear on the center of a rolled material. 11 refs., 13 figs., 2 tabs.

Yanagimoto, J.; Kiuchi, M.; Inoue, Y. (The Univ. of Tokyo, Tokyo (Japan). Inst. of Industrial Science)

1991-09-01

43

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

Directory of Open Access Journals (Sweden)

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.

Farley Santos Ribeiro; José Francisco Cabello Russo; Thiago Costa

2010-01-01

44

The effect of cryogenic grinding and hammer milling on the flavour quality of ground pepper (Piper nigrum L.).  

Science.gov (United States)

In this study, we compared the effects of cryogenic grinding and hammer milling on the flavour attributes of black, white, and green pepper. The flavour attributes were analysed using headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS), sensory evaluation and electronic nose (e-nose) analysis. Cryogenic grinding resulted in minimal damage to the colour, flavour, and sensory attributes of the spices. Cryogenic grinding was also better than hammer milling at preserving the main potent aroma constituents, but the concentrations of the main aroma constituents were dramatically reduced after storing the samples at 4 °C for 6 months. Pattern matching performed by the e-nose further supported our sensory and instrumental findings. Overall, cryogenic grinding was superior to hammer milling for preserving the sensory properties and flavour attributes of pepper without significantly affecting its quality. However, we found that the flavour quality of ground pepper was reduced during storage. PMID:23993499

Liu, Hong; Zeng, Fankui; Wang, Qinghuang; Ou, Shiyi; Tan, Lehe; Gu, Fenglin

2013-06-21

45

The effect of cryogenic grinding and hammer milling on the flavour quality of ground pepper (Piper nigrum L.).  

UK PubMed Central (United Kingdom)

In this study, we compared the effects of cryogenic grinding and hammer milling on the flavour attributes of black, white, and green pepper. The flavour attributes were analysed using headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS), sensory evaluation and electronic nose (e-nose) analysis. Cryogenic grinding resulted in minimal damage to the colour, flavour, and sensory attributes of the spices. Cryogenic grinding was also better than hammer milling at preserving the main potent aroma constituents, but the concentrations of the main aroma constituents were dramatically reduced after storing the samples at 4 °C for 6 months. Pattern matching performed by the e-nose further supported our sensory and instrumental findings. Overall, cryogenic grinding was superior to hammer milling for preserving the sensory properties and flavour attributes of pepper without significantly affecting its quality. However, we found that the flavour quality of ground pepper was reduced during storage.

Liu H; Zeng F; Wang Q; Ou S; Tan L; Gu F

2013-12-01

46

A Cold Rolling Mill Model for Unwinding Diagnosis  

UK PubMed Central (United Kingdom)

A model is presented which describes the uncoiling process of a rolling mill in fault-less andin faulty situations. This model is implemented in the DYMOLA modelling and simulation environment.It is used for two purposes: first for the simulation of the unwinding process and second for model-basedfault diagnosis. For the latter diagnostic task, a simplified model is derived. Results of the successfuldiagnosis, in simulation, concludes the paper.

Lehrstuhl Fr Automatisierungstechnik; Und Prozessinformatik; P. Planchon; J. Lunze; Ruhr-universitat Bochum; M. Rode; M. Schneider; Asea Brown Boveri (abb

47

Modelling and control of a hot rolling mill  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In this paper, a real application of optimal control of a hot rolling mill is presented. It is used the state space model formulation in the minimization of the strip thickness variations. It is presented the simulation results of the control model, which is compared with industrial real data from process controled by traditional techniques. The results of the simulations lead to a less output thickness variations compared with the real industrial data.

Rossomando, F. G.; Denti Filho, J.

2006-07-01

48

Development of rolling mill for rectangular orthodontic wires production  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In orthodontic treatments, wires of different metallic alloys are used for alignment, leveling, correction of the molar position, space closing, finish and retention. The purpose of the paper is the characteristics of austenitic stainless steel wires, with a square traverse section, which were produced using a rolling mill built for this purpose, are presented hereDesign/methodology/approach: With respect to finish and retention, these wires are responsible for adequate positioning of the upper teeth on the lower teeth. Wires that are subjected to incisor torque require high resistance and stiffness. For this, wires of rectangular austenitic stainless steel are used due to high modulus of elasticity and good corrosion resistance in the oral environment. Because of the rectangular geometry, wire production requires process development suitable for industrial scale manufacture with geometric characteristics and mechanical properties better adapted to the use conditions.Findings: To obtain wires with such characteristics, a rolling mill was developed for the production of rectangular wires by a rolling process with the objective of reducing cost of the cold drawing process that is currently used which utilize complex and expensive wire-drawing dies. In addition to the rolling process itself, wire deformation, microhardness, tension and bend tests were also performed.Research limitations/implications: A rolling-mill was built that successfully produced dental wires within acceptable tolerances and physical/mechanical properties.These wires exhibited excellent hardness and tensile strength, although slightly less than analogous commercial wires. It is expected that this problem are corrected by using initial wires with a higher hardness, since this property is directly related with the tensile strength.Originality/value: In these tests, wire geometry, surface finish and mechanical properties were successfully adapted for use in orthodontic treatments.

G.E. Totten; A.I. Filho; C.A.R. Gouvéa; A. Neto; L.C. Casteletti

2007-01-01

49

Rolling mill optimization using an accurate and rapid new model for mill deflection and strip thickness profile  

Science.gov (United States)

This work presents improved technology for attaining high-quality rolled metal strip. The new technology is based on an innovative method to model both the static and dynamic characteristics of rolling mill deflection, and it applies equally to both cluster-type and non cluster-type rolling mill configurations. By effectively combining numerical Finite Element Analysis (FEA) with analytical solid mechanics, the devised approach delivers a rapid, accurate, flexible, high-fidelity model useful for optimizing many important rolling parameters. The associated static deflection model enables computation of the thickness profile and corresponding flatness of the rolled strip. Accurate methods of predicting the strip thickness profile and strip flatness are important in rolling mill design, rolling schedule set-up, control of mill flatness actuators, and optimization of ground roll profiles. The corresponding dynamic deflection model enables solution of the standard eigenvalue problem to determine natural frequencies and modes of vibration. The presented method for solving the roll-stack deflection problem offers several important advantages over traditional methods. In particular, it includes continuity of elastic foundations, non-iterative solution when using pre-determined elastic foundation moduli, continuous third-order displacement fields, simple stress-field determination, the ability to calculate dynamic characteristics, and a comparatively faster solution time. Consistent with the most advanced existing methods, the presented method accommodates loading conditions that represent roll crowning, roll bending, roll shifting, and roll crossing mechanisms. Validation of the static model is provided by comparing results and solution time with large-scale, commercial finite element simulations. In addition to examples with the common 4-high vertical stand rolling mill, application of the presented method to the most complex of rolling mill configurations is demonstrated with an optimization example involving the 20-high Sendzimir mill.

Malik, Arif Sultan

50

Numerical investigation of the grinding process in a Beater Wheel mill with classifier  

Energy Technology Data Exchange (ETDEWEB)

A numerical investigation is presented for a two-dimensional simulation of the gas flow field and of the dynamic behavior of lignite particles inside Beater Wheel mills with classifier, installed in large coal-fired plants. A large number of representative particles are tracked using Lagrangian equations of motion, in combination with a stochastic model for particle turbulent dispersion. All the important mechanisms associated with the particle motion through the mill (particle-surface collisions and rebounding phenomena, fuel moisture evaporation and erosion wear of internal surfaces) are modeled. A special model is constructed to simulate the fragmentation of impacting particles and to calculate the size distribution of the final mill product. The models are regulated on the basis of available data from grinding mills of the Greek lignite power stations. The numerical code is capable of predicting the locations of significant erosion and to estimate the amount of particle mass that circulates through the mill via the classifying chamber. Mean impact velocity and impingement angle distributions along all the internal surfaces are also provided. The results indicate remarkable differences in the extent of the erosion caused at different locations of the mill. Also, the significant role of the leading blades arrangement inside the classifier on its classification performance and efficiency is elucidated.

Anagnostopoulos, J.; Bergeles, G. [National Technical Univ. of Athens (Greece)

1997-07-01

51

On mill flow rate and fineness control in cement grinding circuits: instability and delayed measurements  

International Nuclear Information System (INIS)

[en] A control structure for the mill flow rate and the product fineness is designed, with the feed flow rate and the classifier characteristic as the manipulated variables. Experimental results from a plant highlight the instability of the grinding circuit. A model previously developed by the authors stresses the major influence of the classifier nonlinearities onto this instability. A cascade control structure has been designed and implemented on site. The measurements of the product fineness, sensitive to material grindability fluctuations, are randomly time-delayed. The control structure uses a fineness estimator based on an adaptive scheme and a time delay compensator. (author)

1999-01-01

52

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

2010-07-01

53

The effect of ball milling grinding pathways on the bulk and reactivity properties of calcium phosphate cements.  

UK PubMed Central (United Kingdom)

Calcium phosphate cements (CPCs) are significant alternatives to autologous bone grafting. CPCs can be composed of biphasic or multiphase calcium phosphate (CaP) compounds. A common way to process CPCs is by ball milling. Ball milling can be used for grinding or mechanosynthesis. The aim of this study was to determine the effect of well-defined ball milling grinding parameters, applied via different milling pathways, on the properties of CPCs. Starting CaP compounds used included ?-tricalcium phosphate, dicalcium phosphate anhydrous and precipitated hydroxyapatite. Scanning electron microscopy showed changes in the powder morphology, which were related to the behavior of the starting CaP materials. Specific surface area (SSA) and particle size (PS) measurements exposed the effect of ball milling on the CaP compounds and CPC powders. X-ray diffraction revealed no effect of ball milling pathways or milling time on the composition of CPCs or the starting materials, but affected their crystallographic properties. No contamination of the milling media or transformation into an amorphous calcium phosphate compound was found. The milling pathways affected setting and cohesion. Fourier transform infrared spectroscopy (FTIR) revealed differences on the CPC v?-PO?³? bands according to the interaction, created between the CaP compounds by the milling pathways. FTIR confirmed that the milling pathways changed the crystallographic properties. This study demonstrates that the pathways used for milling grinding modify the PS, SSA, and crystallographic properties of the powders, without affecting their composition. These modifications affected the bulk and reactivity properties of the CPCs by creating different setting and cohesion behaviors.

Lopez-Heredia MA; Bohner M; Zhou W; Winnubst AJ; Wolke JG; Jansen JA

2011-07-01

54

Optimization of a Heavy Continuous Rolling Mill System Via Simulation  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to develop an integrated simulation model, which generates a set of optimizing alternatives for a heavy continuous rolling mill system in a full-scale steelmaking factory. The simulation approach enabled us to evaluate the performance of the existing system and pinpointed existing bottlenecks in workstations and production flow. Consequently, it generated a set of optimum production alternatives. Data related to process and operation times, repairs, maintenance and quality control were collected and analyzed systematically. The simulation model was modeled by Visual SLAM and Awesim simulation language. The results and structure of the computer simulation model were validated and verified against the actual system. Also, the results of the models were discussed and approved by the production managers. The distinct feature of the simulation model is three fold. First, it is integrated and considers detailed operations and activities of the Rolling Mill system. Furthermore, it is designed to be integrated with other workshops of the factory. Second, it locates the optimum solutions by a rule-based methodology. Finally, the model considers the Just-in-Time configuration of the line and is capable of answering all production and inventory issues.

Ali Azadeh; Farid Ghaderi

2006-01-01

55

Saving of electrical energy by the use of vertical roller mills for cement grinding. Final report. Einsparung von elektrischer Energie durch Einsatz von Walzenschuesselmuehlen fuer die Zementmahlung. Schlussbericht  

Energy Technology Data Exchange (ETDEWEB)

As the grinding of cement in ball mills is not energy efficient, a procedure was tried by grinding in a bed of material for greater efficiency. This is the report of the initial tests, the optimising for various sorts of cements and the following three years of operation. The influence of the operating parameters during grinding on the quality of the cement is pointed out. The effect of the abrasive and jet wear on the grinding elements, the inner walls of the mill housing and other internals are described and the measures taken to reduce wear. The connection between energy saving and wear are discussed. Results demonstrate, that the energy efficiency is greater than by grinding in ball mills. The finer the cement, the greater energy savings. The vertical roller mill will be an energy saving and economical cement mill, if the experiences made are considered. With 5 refs., 2 tabs., 5 figs.

Kaemmerer, E.A.

1986-12-01

56

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

International Nuclear Information System (INIS)

[en] 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

2006-01-01

57

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 possible slip line field model was developed adhering strictly to assumptions of rigid plastic model. Calculation of the deforming force/load was achieved using Hencky’s equation. Results showed that the load calculations for constructed slip line field using aluminium sheet rolling as an example tallied with values obtained from Tower Aluminium rolling mill. Slip line fields constructed for the second pass described adequately the rolling pressure in the cold rolling process, giving a valid solution of the exact load estimates on comparison with the industrial load values. Roll pressure along the arc of contact rose fairly linearly from the entrance to a maximum at the exit point. This work showed that slf for the first pass in a cold rolling mill cannot be used for subsequent passes; it requires construction of slfs for each pass in the cold rolling process.

Oluleke O. Oluwole; Olayinka Olaogun

2011-01-01

58

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

Science.gov (United States)

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.

Raghavendra, H.; Bhat, K. L.; Udupa, K. Rajendra; Hegde, M. M. Rajath

2011-01-01

59

INVESTIGATION OF THE MAINTENANCE ORGANISATION FOR HOT ROLLING MILLS  

Directory of Open Access Journals (Sweden)

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 .

P.K. Pretorius; J.K. Visser

2012-01-01

60

Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill  

International Nuclear Information System (INIS)

The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also, the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands

2011-01-01

 
 
 
 
61

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 the 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- (more) 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.

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

2003-03-01

62

Modified oil agglomeration process for coal benefication. 1 Mineral matter liberation by fine grinding with the Szego mill  

Energy Technology Data Exchange (ETDEWEB)

The spherical oil agglomeration technique developed at the National Research Council of Canada (NRC) is an excellent method for cleaning and recovering very small coal particles. The finely ground coal, dispersed in water, is contacted with oil by intensive mixing. The hydrophobic coal particles collect onto the oil droplets to form the agglomerates which are then separated from the aqueous phase by screening. A Szego Mill was used to wet grind Minto (New Brunswick) coal which was then subjected to laboratory agglomeration by the NRC procedure. A comparison with coal ground in a ball mill indicated superior ash rejection. The improved performance is attributed to better mineral liberation which is enhanced by the more flaky particles produced in the Szego Mill. 8 refs., 6 figs.

Bajor, O.; Trass, O.

1988-04-01

63

Evaluation of different pulverisation methods for RNA extraction in squash fruit: lyophilisation, cryogenic mill and mortar grinding.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Quality and integrity of RNA are critical for transcription studies in plant molecular biology. In squash fruit and other high water content crops, the grinding of tissue with mortar and pestle in liquid nitrogen fails to produce a homogeneous and fine powered sample desirable to ensure a good penetration of the extraction reagent. OBJECTIVE: To develop an improved pulverisation method to facilitate the homogenisation process of squash fruit tissue prior to RNA extraction without reducing quality and yield of the extracted RNA. METHODOLOGY: Three methods of pulverisation, each followed by the same extraction protocol, were compared. The first approach consisted of the lyophilisation of the sample in order to remove the excess of water before grinding, the second one used a cryogenic mill and the control one a mortar grinding of frozen tissue. The quality of the isolated RNA was tested by carrying out a quantitative real time downstream amplification. RESULTS: In the three situations considered, mean values for A(260) /A(280) indicated minimal interference by proteins and RNA quality indicator (RQI) values were considered appropriate for quantitative real-time polymerase chain reaction (qRT-PCR) amplification. Successful qRT-PCR amplifications were obtained with cDNA isolated with the three protocols. CONCLUSION: Both apparatus can improve and facilitate the grinding step in the RNA extraction process in zucchini, resulting in isolated RNA of high quality and integrity as revealed by qRT-PCR downstream application. This is apparently the first time that a cryogenic mill has been used to prepare fruit samples for RNA extraction, thereby improving the sampling strategy because the fine powder obtained represents a homogeneous mix of the organ tissue.

Román B; González-Verdejo CI; Peña F; Nadal S; Gómez P

2012-11-01

64

Research upon the quality assurance of the rolling-mill rolls and the variation boundaries of the chemical composition  

Directory of Open Access Journals (Sweden)

Full Text Available The cast-iron rolls must present higher hardness at the rolling surface and lower in the core and the necks, adequate with mechanical resistance and in the high work temperature. If in the zone of the rolling surface, the hardness is guarantied by the irons structure, through the cementite quantities, the core of rolls must contain graphite, to assure this property. Starting from the lamination equipments aspects, from the form of rolls, of the technological interest zones and the structure, which assures the exploitation property, it was establish, through modeling, to the mathematical description of a direct influences, and in final, through successive determinations, to an optimum. One of the parameters, which are determined the structure of the irons destined for rolls casting, is the chemical composition, which guaranties the exploitation properties of the each roll in the stand of rolling mill. The realization of optimum chemical compositions of the cast-iron can constitute a technical efficient way to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having an important role in this sense. Although the manufacture of rolls is in continuously perfecting, the requirements for superior quality rolls are not yet completely satisfied, in many cases, the absence of quality rolls preventing the realization of quality laminates or the realization of productivities of which rolling mills are capable. This paper presents an analysis of the main alloying elements from chemical composition, the influences upon the mechanical properties of the cast-iron rolls, and presents also some graphical addenda. Using the Matlab calculation and graphical programs we determinate some correlations between the hardness (on the working surface and on necks) and the chemical composition. Using the double and triple correlations is really helpful in the foundry practice, as it allows us to determine variation boundaries for the chemical composition, in view the obtaining the desired and optimal values of the hardness of this very important metallurgical equipments. The enunciation of some mathematically modeling results, described through a number of multi-component equations determined for the spaces with 3 the and 4 dimensions, as well as the generation of some regression surfaces, of some curves of levels and volumes of variation, can be represented and interpreted by technologists and can be considerate diagrams of correlation between the analyzed variables. From this point of view the research is inscribes in context of scientific capitalization of the process and the industrial technologies optimizations, on the way of the analysis and the mathematical experiment.Los cilindros o rodillos de laminación de función deben presentar una dureza más alta en su superficie y menor en el núcleo y el cuello del cilindro, adecuados a la resistencia mecánica y a la alta temperatura de trabajo. Si en la zona de la superficie de rodillo, la dureza se garantiza por las cementita existente en la estructura, el núcleo del cilindro debe tener grafito para asegurar la característica deseada. A partir de consideraciones sobre los equipos de la laminación, forma de los cilindros de laminación, zonas tecnológicas del interés y de la estructura, que asegura la característica de la explotación, se estableció un modelo que da una descripción matemática de las influencias directas y, finalmente, mediante determinaciones sucesivas, permite establecer un óptimo. Uno de los parámetros, que determinan la estructura del material de los cilindros de laminación es su composición química, que garantiza las características de la explotación de cada cilindro en el laminador. El empleo de las composiciones químicas de colada, óptimas, puede ser una manera técnicamente eficiente de asegurar las características de la explotación; el material de fabricación de los cilindros juega un papel importante. Aunque la fabricación de cilindros es objeto de una mejora continua, los requis

Kiss, I.

2008-01-01

65

Rolling process simulation of a pair-crossed hot strip mill  

Energy Technology Data Exchange (ETDEWEB)

Process simulation can help optimize the operating parameters aiming to improve the quality of rolled products. In this paper, software in Visual Basic language is developed to simulate the hot rolling process of a pair-crossed mill. The strip temperature is calculated by considering air cooling, water cooling, heat generation and conduction.The production parameters including rolling speeds, resistance to deformation, rolling forces, drive torques and powers are evaluated by mathematical models and their parameter identification support tools. The deformation of roll stack is calculated by influential function method. The roll temperature and expansion are calculated by finite differential method, and the roll wear is described by empirical formula. Based on these calculations as well as the effect of heredity is taken into account, the strip crown and flatness then can be obtained. The results show that the simulation software has friendly user interface, high accuracy and practicability. It can be served as a basis for the mill design and optimization of process parameters to acquire high quality of hot rolled strip. (author)

Chen Shaojie; Xu Jianzhong; Liu Xianghua; Wang Guodong [Northeastern Univ., State Key Lab of Rolling and Automation, Shenyang City (China)

2000-07-01

66

Rolling process simulation of a pair-crossed hot strip mill  

International Nuclear Information System (INIS)

Process simulation can help optimize the operating parameters aiming to improve the quality of rolled products. In this paper, software in Visual Basic language is developed to simulate the hot rolling process of a pair-crossed mill. The strip temperature is calculated by considering air cooling, water cooling, heat generation and conduction.The production parameters including rolling speeds, resistance to deformation, rolling forces, drive torques and powers are evaluated by mathematical models and their parameter identification support tools. The deformation of roll stack is calculated by influential function method. The roll temperature and expansion are calculated by finite differential method, and the roll wear is described by empirical formula. Based on these calculations as well as the effect of heredity is taken into account, the strip crown and flatness then can be obtained. The results show that the simulation software has friendly user interface, high accuracy and practicability. It can be served as a basis for the mill design and optimization of process parameters to acquire high quality of hot rolled strip. (author)

2000-01-01

67

High Temperature Thermal Expansion and Elastic Modulus of Steels Used in Mill Rolls  

Science.gov (United States)

The high temperature thermal expansion coefficient (TEC) and elastic modulus of five steels used in mill rolls production were investigated by dilatometer and impulse excitation techniques (IET). The measurements were provided at heating from room temperature till temperatures of about 1000 °C and subsequent cooling. The obtained data were attributed to the properties of predominating phases (austenite, martensite, pearlite, and bainite). The TEC and elastic modulus of corresponding phases were similar for all investigated steels despite the difference in their chemical composition. The steels with a chromium content of 2.95 wt.% and more show enhanced ability to quench hardening. This is an important prerequisite for production of high quality mill rolls.

Laptev, Alexander; Baufeld, Bernd; Swarnakar, Akhilesh Kumar; Zakharchuk, Stanislav; van der Biest, Omer

2012-02-01

68

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

International Nuclear Information System (INIS)

[en] 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

2008-06-12

69

Tribological Testing of Anti-Adhesive coatings for Cold Rolling Mill Rolls--Application to TiN-Coated Rolls  

International Nuclear Information System (INIS)

Roll life is a major issue in cold strip rolling. Roll wear may result either in too low roll roughness, bringing friction below the minimum requested for strip entrainment; or it may degrade strip surface quality. On the contrary, adhesive wear and transfer (''roll coating'', ''pick up'') may form a thick metallic deposits on the roll which increases friction excessively and degrades strip surface again [1]. The roll surface, with the help of a materials-adapted lubricant, must therefore possess anti-wear and anti-adhesive properties. Thus, High Speed Steeel (HSS) rolls show superior properties compared with standard Cr-steel rolls due to their high carbide surface coverage. Another way to improve wear and adhesion properties of surfaces is to apply hard metallic (hard-Cr) or ceramic coatings. Chromium is renowned for its excellent anti-wear and anti-adhesive properties and may serve as a reference. Here, as a first step towards alternative, optimised coatings, a PVD TiN coating has been deposited on tool steels, as previous attempts have proved TiN to be rather successful in cold rolling experiments [2,3]. Different tribological tests are reported here, giving insight in both anti-adhesive properties and fatigue life improvement.

2011-05-04

70

Force prediction in cold rolling mills by polynomial methods  

Directory of Open Access Journals (Sweden)

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.

Nicu ROMAN; Bogdan IONITA; Dorel AIORDACHIOAE; Emil CEANGA; Ion BIVOL

2007-01-01

71

Optimization of cold rolling procedure using reversing mill  

International Nuclear Information System (INIS)

Optimum procedures of the band cold rolling of the 12Kh18N9T steel and 7KhNM alloy are calculated according to the developed algorithm. Results of calculations of optimum procedures of rolling are given. It is shown that realization of optimum procedure will permit to produce a plotting band with minimum cross section different-thickness at simultaneous reduction of a number of gaps

1980-01-01

72

Regulated rolling of thick-sheet steel using 2800 mill  

International Nuclear Information System (INIS)

A study was made on possibility of thermal strengthening of sheet low-alloy steel of up to 16 mm thickness, using heat of rolling heat and cooling in the system of automatic controlling temperature of rolling termination (SACTRT). It was recommended to produce 10KhSND steel sheets of 14 mm and less thickness with 0.46 and more factor of chemical composition according to the following technology: to terminate rolling in finishing stand at 870...900 deg.C and then to cool them in SACT RT down to 650...750 deg.C. The developed technology provides the complex of mechanical properties in accordance with requirements of 19282-73 All Union State Standard for 90% of metal. Sheets with unsatisfactory properties are subjected to heat treatment, beginning from special heating

1988-01-01

73

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)

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.)

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

2010-07-01

74

Merging of advices from multiple advisory systems - with evaluation on rolling mill data.  

Czech Academy of Sciences Publication Activity Database

multiple-participant decision-makingKód oboru RIV: BC - Teorie a systémy ?ízení http://library.utia.cas.cz/separaty/2009/AS/andrysek-merging of advices from multiple advisory systems-with evaluation on rolling mill data.pdf

Ettler, P.; Andrýsek, JosefG; Šmídl, Václav; Kárný, Miroslav

75

Self-Tuning Controller for Rolling Mill Processes. Interim Progress Report.  

Science.gov (United States)

This report presents an adaptive self-tuning controller for the control of the rolling mill. This controller is designed on the basis of a time-series model (AR model) in which the parameters are estimated recursively on the basis of the available informa...

I. Papapanagiotou G. Maliotis A. J. Koivo

1984-01-01

76

Design of Rolling State Observers for Application to Control of Thickness and Tension in Rolling Mills  

Directory of Open Access Journals (Sweden)

Full Text Available This study focuses on the necessity of designing state observers to be used in controller synthesis for rolling processes. This is motivated by the fact that using several kinds of sensors for measuring all of process variables is technically and economically avoided. On the other hand, using exact measurement in feedback control systems could considerably improve the quality of products. In other word, there is a trade-off between high quality and the implementation limitations, managed here by developing rolling state observers. The proposed observers estimate the states not measured directly by the installed sensors. This technique is applicable to both hot rolling and cold rolling processes. Simulation results demonstrate the performance of the proposed estimation algorithm.

Hamid R. Koofigar; Shahab Amelian

2011-01-01

77

Rolling of U-shaped and H-shaped wires by the satellite mill; Satellite mill ni yoru U kei oyobi H kei ikeisen no atsuen  

Energy Technology Data Exchange (ETDEWEB)

Authors have developed a compact continuous mill named the satellite mill. This mill had characteristics in which the elongation of materials was controlled and the transverse metal flow was promoted. In this study, the rolling properties and the product properties were investigated in the formation of U-shaped and H-shape profiled wires by the rolling of the satellite mill using the closed passes. The following results were obtained: By using the satellite mill rolling, the transverse rib heights for both U-shaped and H-shaped profiled wires were much higher than those by the conventional rolling, for significant decreasing of elongation and promotion of the transverse metal flow. In the satellite mill rolling, the material speed for both U-shaped and H-shaped profiled wires was controlled by the rotation speed of the central roll groove, and was almost the same with the rotation speed of the central roll groove in the middle part. The transverse hardness peaks of U-shaped and H-shaped profiled wires existed at the corner and two sides of webs, and the hardness was lower at the tip parts of ribs. 4 refs., 10 figs.

Kawamoto, T. Utsunomiya, H.; Saito, Y. [Osaka Univ., Osaka (Japan). Gaduate School

1998-04-01

78

Regulation of the Heating Furnace in Tube Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The rolling of tube requires homogeneous heating along the tube. In steel work the difference along tube was sometimes 80 °C. The reasons for bad homogeneousness of heating were analyzed by a simulation model of heating furnace. Then the proposal was made for a new control system and also the proposal for reconstruction of furnace. In this contribution also a description of some ways for improvement of heating was made. The main contribution is the proposal of an adaptive system

Kostúr, K.

2006-01-01

79

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

Directory of Open Access Journals (Sweden)

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.

J. Krawczyk; J. Pacyna

2010-01-01

80

Strip/Foil Rolling Mill Stochastic Excitation Model and Its Stability  

Directory of Open Access Journals (Sweden)

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.

Baoyu Xu; Xudong Wang; Yilun Liu; Haichao Feng

2012-01-01

 
 
 
 
81

The Modelling and Control of Interst and Coolling of Rolled Steell in Billet Mills  

Directory of Open Access Journals (Sweden)

Full Text Available A generalized approach to the modelling of transient heat flow in rolled steel during air-cooling in billet mills is presented. The mathematical development starting with the relevant differential equations and their modelling using the Hills’ integral profile method give polynomial functions which characterize the transient heat flow in the workpiece and establishes an optimal control law for static cooling conditions. An experimental validation test enabled the final model to be obtained as a function of the rolling speed and shows that a good functional correspondence exists between the model and the data reported in the literature.

E.C. Obinabo

2008-01-01

82

Performance and Application of a Multiphase Thyristor Motor with a DC Link for Metal-Rolling Mills.  

Science.gov (United States)

Recent demand for reduced power consumption, higher performance, and greater freedom from maintenance requirements has stimulated the replacement of DC motors by AC motors in metal-rolling mills. A multiphase thyristor motor with a DC link has been develo...

T. Asaeda T. Matsuura Y. Tominaga Y. Hosokawa M. Tominaga

1983-01-01

83

Analysis of the kinetics of coal breakage by wet grinding in the Szego mill  

Energy Technology Data Exchange (ETDEWEB)

The paper deals with the mechanism of breakage of Pittsburgh coal in the Szego mill, for the preparation of coal-oil and coal-water slurries. The kinetics of coal breakage is discussed, and a two-component model is used to explain the breakage.

Koka, V.R.; Trass, O.

1985-08-01

84

Numerical simulation of grinding and drying performance of a fluid-energy lignite mill  

Energy Technology Data Exchange (ETDEWEB)

A numerical algorithm is developed for a detailed 3D simulation of the two-phase flow field in fluid-energy mills used for pulverizing and drying of fossil fuels in large power plants. The gas phase equations are solved using finite differences and the control volume method, whereas a Lagrangian formulation with a stochastic particle dispersion model is adopted for the particulate phase. Fluid-particle interaction is taken into account to calculate the mass, momentum, and heat transfer between phases. Advanced numerical techniques for partially-blocked cells and local grid refinement have been utilized to achieve an accurate representation of the domain geometry and to enhance the accuracy of the results. Particle collisions, fragmentation mechanism, and moisture evaporation are simulated by corresponding models, whereas the special treatment employed for the rotating fan region provides the capability to solve the two-phase flow simultaneously in the entire rotating and nonrotating mill domain. The flow and the operation characteristics of a recently developed lignite mill are measured, and the numerical algorithm is used to predict the mill performance under various inlet profiles of the fuel mass flow rate.

Anagnostopoulos, J.; Bergeles, G.; Epple, B.; Stegelitz, P. [Technological Educational Institute of Kozani, Kozani (Greece). Dept. of Mechanical Engineering

2001-06-01

85

Settling stability of coal slurries prepared by wet grinding in the Szego mill  

Energy Technology Data Exchange (ETDEWEB)

Static sedimentation experiments on coal-No.2 oil and coal-water slurries, wet ground in a Szego mill, were conducted. These slurries contain more flaky particles as compared to those conventionally ground. Concentration and size distribution of the coal, diameter and height of the settling columns and settling time were the independent variables. Coal concentration and particle size distribution along the columns, and settling rates were measured. Despite their particle shape differences, these slurries were similar to others in terms of settling stability due to particle flocculation. 12 references.

Koka, V.R.; Papachristodoulou, G.; Trass, O.

1985-08-01

86

Recent trends in shape mills. ; Hyper beam rolling mill. Katako atsuen setsubi no saikin no doko. ; Haipa bimu no atsuen setsubi ni tsuite  

Energy Technology Data Exchange (ETDEWEB)

'HYPER BEAM' is an advanced type of H-shapes for structural purposes, featuring high fabrication efficiency due to the uniformity of web height and light weight due to thinner webs. The HYPER BEAM manufacturing technology has been established by developing a new type of skew roll mill for high-precision width-spreading and a finishing mill with variable barrel-width rolls for finishing the width-spread material to a desired width. To produce webs far thinner than flanges, a flange cooling equipment which can effectively cool the flanges only with water has been developed. Moreover, a new type of roller straightening machine with an automatic in-line roller barrel-width changing function has been developed to strengthen the shapes as appropriate depending on the inside width of the web. In this report, the skew roll mill, the finishing mill with variable barrel-width rolls, the flange cooling equipment and the roller straightening machine with an automatic in-line roller barrel-width changing function which are core hardwares for realizing HYPER BEAM rolling were described particularly. 5 refs., 20 figs., 1 tab.

Kitamura, T.; Hioki, T.; Nakano, Y.; Ikezaki, T.; Haji, T.; Fujita, K.; Teramae, A. (Nippon Steel Corp., Tokyo (Japan))

1992-11-30

87

A Simple Method of Designing Dual loop Controller for Cold Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The mathematical model (Interval Plant) of the web guide in rolling mill is controlled using PID controller. The given interval plant is approximated to first order plus time delay with integrator (FOPTDI) system. The dual loop control (DLC) method proposed by Jacob and chidambaram for design PID controllers is extended for FOPTD+I systems. The performance of the closed loop system is evaluated for both the original and the approximated model. The controllers are also tuned using Internal Model Control (IMC) and the performance is compared by simulation.

S. Umamaheswari,; V.Palanisamy,; M.Chidambaram

2010-01-01

88

Numerical Simulations of the Flow of Dilute Polymer Solutions in a Four-Roll Mill  

Science.gov (United States)

We study the startup flow of dilute polymer solutions in a four-roll mill by using FENE dumbbell models. The first objective of the paper is to examine the behavior of the Chilcott-Rallison version of the FENE model (FENE-CR) with varying parameters c, De and L. The coupling between flow and polymer stretching is exhibited by concerted flow suppression and reduction of polymer extension. In particular, the model predicts double-humped velocity and strain rate profiles across the outflow axis, in qualitative agreement with experiments. The second objective of the paper is to study the effects of other features that can be added to the basic FENE-CR model, including conformation-dependent friction (CDF), shear-thinning and an extra viscous stress term. The FENE-CDF model is specially interesting because of its relevance to the phenomenon of birefringence pipe. For the range of parameters studied, the FENE-CDF model does produce more severe flow suppression than the FENE-CR model, but not sufficiently so that the polymer collapses to the coiled state. The shear-thinning in the FENE-P model and the extra viscous stress do not have a significant effect on the startup flow in the four-roll mill.

Feng, J.; Leal, L. G.

1996-11-01

89

Power quality at Gerdau MRM Steel : a rolling mill`s perspective  

Energy Technology Data Exchange (ETDEWEB)

Power quality issues facing Gerdau MRM Steel, a steel mill operation in Selkirk, Manitoba were discussed. It was noted that power interruptions in various process equipment result in production loss, but the effects of harmonics and surges are harder to quantify. Some equipment, such as DC drives, variable-speed AC drives, computers and solid state equipment are sensitive to short term drop-outs and harmonic distortion. This type of equipment can also cause harmonic distortion. Some causes of sags, drop-outs and interruptions such as weather, switching, faults, accidents and human error were also reviewed. It was concluded that power quality problems at the plant can be resolved with support from the electric utility as well as from plant operations.

Shymanski, W.T. [Gerdau MRM Steel, Selkirk, MB (Canada)

1998-12-31

90

Validation of a 3-D, Thermo-Mechanically Coupled Model for Multi-Pass Rolling in a Reversing Mill  

Energy Technology Data Exchange (ETDEWEB)

A three dimensional numerical model simulating multi-pass, hot rolling on a reversing mill has been developed to analyze deformation patterns and shape changes of a rolled ingot. Validation simulations through 15 passes with an 86% reduction have been performed using the thermo-mechanically coupled model to track the evolution of the deformed ingot geometry. The heat transfer coefficient for thermal conduction between the rolls and slab has been estimated in accordance with experimental data, and heat transfer to the air and coolant outside of the roll bite is included. A hyperbolic sine model using the Zener-Hollomon parameter is used to capture the temperature and strain rate dependence of the aluminum alloy. A Coulomb friction model with a flow strength dependent maximum limit on the interfacial shear stress was employed between the rolls and ingot. Results of validation simulations and comparisons with experiments focusing on the ingot shape evolution are discussed.

Rhee, M; Wang, P; Li, M; Becker, R

2004-01-30

91

The production of aligned short fibre ceramic matrix composites using a twin rolling mill  

Energy Technology Data Exchange (ETDEWEB)

A novel powder processing route for short fibre ceramic matrix composites (CMCs), based on using a twin rolling mill, has been developed. This has been seen to be an efficient and easy way of mixing the composite constituents while obtaining a high degree of fibre alignment. The production of the green composites by this method has taken an average of ten minutes. In this report a system of Nicalon fibres in silicon, subsequently reaction bonded to form a matrix of reaction bonded silicon nitride, has been emphasised. Composites with fibre loading of up to 34% fibre volume fraction have been produced, microscopically analysed, and mechanically tested. A novel way of introducing fibres into the ceramic matrix has removed the problems associated with chopping and handling the fibres. This technique will be developed so that prospective ceramic matrix composite can be efficiently produced in prototype quantities for further appraisal of their properties. (orig.)

Philpott, E. [DRA, Farnborough (United Kingdom). Struct. Mater. Center; Shatwell, R. [DRA, Farnborough (United Kingdom). Struct. Mater. Center; Kendall, K. [Keele Univ. (United Kingdom). Dept. of Chem.

1997-06-01

92

Self-tuning controller for rolling mill processes. Interim progress report  

Energy Technology Data Exchange (ETDEWEB)

This report presents an adaptive self-tuning controller for the control of the rolling mill. This controller is designed on the basis of a time-series model (AR model) in which the parameters are estimated recursively on the basis of the available information (on-line). The controller gains are determined at each sampling instant so that the outputs follow the desired values as closely as possible. The self-tuning controller is thus in the form of a feedback controller, whose gains are calculated continuously on-line. The basic time-series model which relates the inputs to the outputs of the system will be described first, then the controller algorithm. Simulation studies on the resulting system are presented to demonstrate the applicability of the approach.

Papapanagiotou, I.; Maliotis, G.; Koivo, A.J.

1984-01-01

93

Transport, mixing and stretching in a chaotic Stokes flow: The two-roll mill  

International Nuclear Information System (INIS)

We present the outline and preliminary results of an analytical and numerical study of transport, mixing, and stretching in a chaotic Stokes' flow in a two-roll mill apparatus. We use the theory of dynamical systems to describe the rich behavior and structure exhibited by these flows. The main features are the homoclinic tangle which functions as the backbone of the chaotic mixing region, the Smale horseshoe, and the island chains. We then use our detailed knowledge of these structures to develop a theory of transport and stretching of fluid in the chaotic regime. In particular, we show how a specific set of tools for adiabatic chaos- the adiabatic Melnikov function lobe area and flux computations and the adiabatic switching method is ideally suited to develop this theory of transport, mixing and stretching in time-dependent two-dimensional Stokes' flows. 19 refs., 8 figs

1989-01-01

94

Automation system for heat treatment furnaces of roll mill rolls; Sistema de automacao dos fornos para tratamento termico de cilindros de laminacao de Acos Villares  

Energy Technology Data Exchange (ETDEWEB)

the heat treatment process of roll mill rolls operates with very closely controlled thermal cycles and very tight temperature tolerances, and this is fundamental for the good quality and future performance of the product. Albeit our furnaces already coped with the basic conditions for doing this, the roll mill rolls market is each day more demanding and more competitive, making a necessity the modernization of this equipment. The project consisted basically in changing the heat source from the light fuel oil C4 and the manual control of the equipment to a new concept of operation, using pulsating natural gas burners and automation. This was made installing in each of our 11 furnaces, ten pulsating gas burners with full automation. The project uses thirty three process controllers, eleven temperature programmers, linked to a data collection station and two P C supervising workstations. This equipment are all installed in a control room, making possible a good control of the furnaces. The supervisory systems are now being linked with our production planning and scheduling systems, integrating our shop-floor in real time with our administrative needs. This work presents the principal characteristics of this automated heat treatment system, the supervising and ata administration system, and the mean benefits obtained with this project. (author) 2 refs., 7 figs.

Malere, Ernesto P.; Silva, Sergio P.; Correa, Nicolas I.B. [Acos Villares SA, Sao Caetano do Sul, SP (Brazil)

1996-12-31

95

Special technique for cleaning the lubrication system of rolling mill roll grinder slide way; Tecnica especial para limpeza em sistema de lubrificacao de barramento de retificadoras de cilindros da laminacao  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the abnormalities found prior to the application of a special technique for cleaning the lubrication system of rolling mill roll grinder slide waw, the explanation on the technical procedure developed by Companhia Siderurgica Nacional and the outstanding results obtained after the implementation aforesaid technique 3 figs.

Kaneko, J.T.; Dib Junior, A.; Dias, L.C.G. [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)

1995-12-31

96

New compression grinding technologies  

Energy Technology Data Exchange (ETDEWEB)

The development of roller presses in pregrinding has shown the advantages of compression grinding over the ball mill from the power consumption point of view. But classical roller presses still have maintenance problems due to the high grinding pressure. The FCB Research Centre has carried out much work in this field and in particular has studied the advantages of this process in pregrinding and integral grinding. These researches lead to the development of two new compression grinding machines. The first one, HOROMILL{reg_sign}, presented for the first time on the 8th European symposium on comminution at Stockholm, finds its application in the field of fine to very fine grinding in dry process. The second one, RHODAX{reg_sign}, presented at INTERMAT in Paris, covers the field of secondary and tertiary crushing and the first stage of grinding for most of the minerals in dry or wet process. Its high reduction factor permits to do with only one machine the work realized today with two or three crushing/milling stages.

Cordonnier, A.; Evrard, R.; Obry, C. [FCB CRCM Research Centre, Lille (France)

1995-12-31

97

The Physical Flow of Materials and the Associated Costs in the Production Process of a Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available Efficiency of resources use is, in a large extent, determined by the organization of production flow and the way of their control. The optimization of materials flow in the production process requires the identification of physical flows of goods and it cost. In the article the physical flow process of materials stream in the production process in one of Polish rolling mill and also its logistics analysis and cost analysis are presented.

Holisz-Burzy?ska, J.; Staniewska, E.; Budzik, R.

2007-01-01

98

Evaluation of residual uranium contamination in the dirt floor of an abandoned metal rolling mill.  

UK PubMed Central (United Kingdom)

A single, large, bulk sample of uranium-contaminated material from the dirt floor of an abandoned metal rolling mill was separated into different types and sizes of aliquots to simulate samples that would be collected during site remediation. The facility rolled approximately 11,000 tons of hot-forged ingots of uranium metal approximately 60 y ago, and it has not been used since that time. Thirty small mass (? 0.7 g) and 15 large mass (? 70 g) samples were prepared from the heterogeneously contaminated bulk material to determine how measurements of the uranium contamination vary with sample size. Aliquots of bulk material were also resuspended in an exposure chamber to produce six samples of respirable particles that were obtained using a cascade impactor. Samples of removable surface contamination were collected by wiping 100 cm of the interior surfaces of the exposure chamber with 47-mm-diameter fiber filters. Uranium contamination in each of the samples was measured directly using high-resolution gamma ray spectrometry. As expected, results for isotopic uranium (i.e., U and U) measured with the large-mass and small-mass samples are significantly different (p < 0.001), and the coefficient of variation (COV) for the small-mass samples was greater than for the large-mass samples. The uranium isotopic concentrations measured in the air and on the wipe samples were not significantly different and were also not significantly different (p > 0.05) from results for the large- or small-mass samples. Large-mass samples are more reliable for characterizing heterogeneously distributed radiological contamination than small-mass samples since they exhibit the least variation compared to the mean. Thus, samples should be sufficiently large in mass to insure that the results are truly representative of the heterogeneously distributed uranium contamination present at the facility. Monitoring exposure of workers and the public as a result of uranium contamination resuspended during site remediation should be evaluated using samples of sufficient size and type to accommodate the heterogeneous distribution of uranium in the bulk material.

Glassford E; Spitz H; Lobaugh M; Spitler G; Succop P; Rice C

2013-02-01

99

Production of a preparation for bread spread, comprises chopping sun flower seeds, soya beans, pulses or cereals in a closed cutter, grinding the substance in ceramic high pressure mill and feeding the ground mixture to corundum disc mills  

UK PubMed Central (United Kingdom)

The production of a preparation for a bread spread, comprises chopping sun flower seeds (12), soya beans, pulses or cereals together with water (14) and/or without an acidifier and an oil, like sunflower oil (13) or olive oil in a closed cutter (10) during subjecting of heat by the application of vacuum in the cutter-inner space, grinding the chopped and heated mixture in a ceramic high-pressure mill to a particle-size distribution of 0.3-200 mu m with an outer surface of 1.0-1.5 m2>/g, and feeding the ground mixture via a shaft screw pump to a corundum disc mill (30). The production of a preparation for a bread spread, comprises chopping sun flower seeds (12), soya beans, pulses or cereals together with water (14) and/or without an acidifier and an oil, like sunflower oil (13) or olive oil in a closed cutter (10) during subjecting of heat by the application of vacuum in the cutter-inner space, grinding the chopped and heated mixture in a ceramic high-pressure mill to a particle-size distribution of 0.3-200 mu m with an outer surface of 1.0-1.5 m2>/g, and feeding the ground mixture via a shaft screw pump to a corundum disc mill (30). The chopping is carried out during the simultaneous introduction of additional water in the form of direct vapor through vapor discharge nozzles on the floor or on the cover part of the cutter. The end product to be filled in containers (40) is sterilized or pasteurized in a vapor autoclave and then cooled at = 30[deg] . The chopping of the initial substances is carried out in the cutter by 1500 revolutions of the cutter knife for 1-1.5 minutes and is finally carried out by the cutter knife revolutions of 3000 revolutions over 1-1.5 minutes. The chopped mixture is finely ground so that it becomes free-flowing and pumpable product. The ground product and further additives like spices, bear's garlic or food colorants are fed into an agitator- and reservoir container. The head part of the container, which is filled with the heated product is vaporized with a dry vapor and is heated at 150[deg] C. The container is sealed and then its content is cooled by spraying the container with cold water. Independent claims are included for: (1) preparation for bread spread and (2) plant for manufacturing a preparation for bread spread.

SCHOENING SUSANNE

100

Expert system for diagnosis of strip thickness accuracy in cold rolling tandem mill. Reikan tandem mill itaatsu seido shindan expert system  

Energy Technology Data Exchange (ETDEWEB)

In order to maintain a quality and to support a control system maintenance, the realtime diagnostic eepert system for fully continuous cold rolling tandem ills was developed to detect the anomaly of strip thickness and to infer its cause in an automatic gauge control system and hydraulic push-up roll gap control system. The system was composed of a conventional procedural programmed system and knowledge base system. The data for inference were formed on the basis of information from the equipment diagnosis system and mill control PLC (programmable logic controller), and the cause was inferred of the coil anomaly detected at two rolling points, an intermediate point with top-speed and a shear cut point of coils. The prototype method was adopted in system development to utilize the merit of the knowledge base enough while tuning it. In real operations, a fast response within 8 sec was achieved through distributed functions for rapid gathering, processing and editing of operation data, and realtime inference. 3 refs., 8 figs., 2 tabs.

Iguchi, H.; Kitao, N.; Sano, K.; Iritsuki, K.; Karasawa, N.; Komatsu, T. (Kawasaki Steel Corp., Kobe (Japan))

1991-11-01

 
 
 
 
101

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)

Full Text Available Abstract in spanish 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 dis (more) tribución 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, mine (more) ralogy 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.

OSORIO, ADRIANA; RESTREPO, GLORIA; MARÍN, JUAN

2009-06-01

102

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1990-07-01

103

Influence of wheat milling on low-hydration bread quality developed by sheeting rolls.  

Science.gov (United States)

It is well known that milling influences the characteristics of flour and products made from it. This article analyzed the influence of milling on the quality of low-hydration bread. In general, milling influenced the quality of these products more than the type of wheat selected. Among the various mill streams, the last break and reduction streams produced lower quality bread and must be eliminated in milling. These streams had a higher protein and ash content, showing the presence of components of the outer layers of the grain. The flour was able to absorb more water, but had less extensibility in kneading and the dough generated was weaker due the poorer quality of its proteins and the influence of elements from the outer layers. Thus, bread made from these streams had smaller volume, had a firmer texture and had both darker crumb and crust. These differences, along with the effect of the kind of flour on the flavor and aroma of the bread, made it less acceptable than flour from the rest of the streams studied. PMID:21551227

Gómez, M; Ruiz-París, E; Oliete, B

2011-05-06

104

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 evaluated. 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 t (more) here 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.

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

2013-02-01

105

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

Directory of Open Access Journals (Sweden)

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 evaluated. 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.

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

2012-01-01

106

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

Directory of Open Access Journals (Sweden)

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 evaluated. 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.

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

2013-01-01

107

Endless hot strip rolling at No.3 hot strip mill in China works; Chiba seitetsusho dai 3 netsuen kojo ni okeru endless atsuen gijutsu  

Energy Technology Data Exchange (ETDEWEB)

Development of the technology and the operation of the mill are outlined. Endless hot strip rolling is adopted to improve on sheet quality at its leading and trailing edges and on smoothness in sheet feeding during the rolling process, to manufacture thin and wide,or very thin, steel sheets, and to realize lubricated rolling throughout the sheet length. For the implementation of endless rolling, a sheet bar coiler, joining unit, deburring device, and strip shear are installed. Thanks to the newly developed joining technology making use of induced heating and upsetting, sheet bars can be joined in about 5 seconds. Bars were joined by the real mill and the joint was examined, when it was found that the joint was as strong as the parent material. No break occurred in the joint during the finishing process. The endless rolling process achieved a sheet thickness precision of {plus_minus} 25{mu}m throughout the sheet length. It is now possible to produce with stability 1.2mm-thick, 1600mm-wide sheets, and sheets so thin as 0.8-1.2mm. 11 refs., 10 figs., 2 tabs.

Nikaido, H.; Isoyama, S.; Nomura, N. [Kawasaki Steel Corp., Tokyo (Japan); Hayashi, K.; Morimoto, K.; Sakamoto, H. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

1997-03-01

108

Surface finishing and levelling of thermomechanically hardened rolled steel  

International Nuclear Information System (INIS)

The finishing of high-strength merchant shapes from alloy steel was tried out under industrial conditions with the equipment of metallurgical plants. After thermomechanical hardening in the production line of the rolling mill, 30KhGSN2A and 40Kh1NVA steel rounds 32 and 31 mm in diameter were straightened on a two-roller straightening machine designed by the All-Union Scientific Research Institute for Metallurgical Machinery (VNII Metmash). This made possible subsequent turning and grinding of the rods. The conditions of straightening, turning and grinding have been worked so as to obtain thermomechanically strengthened and ground rolled products approximating the gauged and ground metal in shape geometry and surface finish. It is shown that the labour-consuming operation of turning can be eliminated by reducing the machining pass of the rolled product, and this lowers the labour required for the finishing operations by 75%. After grinding with 40- and 25-grain abrasive wheels, high strength rolled shapes were obtained with a diameter of 30-0.20 mm and a surface finish of class 6-5 satisfying the technical specifications. (author)

1975-01-01

109

Cost factors in fine grinding of coal  

Energy Technology Data Exchange (ETDEWEB)

Information has been gathered on the effects of coal characteristics and mill design and operation on the costs of grinding coal to the 10 microns size range. The greatest cost factor in fine coal grinding using stirred bed technology is media wear. As the size of the chrome steel grinding media balls is reduced from 3.8 inch to 3/16 inch diameter the specific media loss rate more than doubles and the cost of replacement media increases by a factor of four. The specific media loss rate is directly related to the ash content of the coal. The tests were carried out using a 5-horsepower Pitt Mill prototype. The cost of grinding 50 HGI coal to between 10 and 20 {mu}m in the Pitt Mill is estimated at 29 to 10 dollars per ton respectively. 17 refs., 6 figs., 8 tabs.

Borzone, L.A.; Oder, R.R. (EXPORTech Company Limited, New Kensington, PA (USA))

1992-01-01

110

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

Directory of Open Access Journals (Sweden)

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 causado 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.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 order 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.

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

2005-01-01

111

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)

[en] 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)

1976-01-01

112

Analysis of rolling characteristics in a continuous billet mill with drive-free vertical rolls. Mukudo suichoku roll wo yusuru renzoku billet atsuenki ni okeru atsuen tokusei no kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Based on the rolling data obtained from a rolling experiment using five-stand continuous steel rolling machines as have been reported previously, analyses were made on rolling loads on driven and non-driven stands, rolling torque in the driven stand, and inter-stand tension. In analyzing the rolling load variation, it was revealed that the variation can be explained by use of the inference equation for hole type rolling load by Yanagimoto that takes fore and rear tension into account. In analyzing the rolling torque variation, equations to express torque arm coefficients accounting for the fore and rear tension, and inter-stand tension were introduced. For the analysis of rolling material width variation, an equation that considers the fore and rear tension was introduced. This equation indicates a width spread being affected largely by rear tension, which agrees also with experimental facts. Forced rolling was analyzed theoretically. Compressive stress calculations using the resultant equations agreed approximately well with the measurements. Rolling loads were inferred in a similar manner, of which result was verified capable of inferring the loads within an error range of [plus minus]10% of the measured values. The inference on the required rolling torque corresponded also well with the measurements. 12 refs., 12 figs., 1 tab.

Shikano, H. (Sumitomo Metal Industries, Ltd., Osaka (Japan))

1992-12-01

113

Improvements in the manufacturing of rolling mill rolls through a new system of production planning, scheduling and control; Melhorias na manufatura de cilindros de laminacao atraves de um novo sistema de planejamento, programacao e controle da producao  

Energy Technology Data Exchange (ETDEWEB)

This work presents the implementation of new system for production planning, scheduling and control in the rolling mill rolls unit, at Acos Villares, the occurred changes and the attained results. This system provided automation steps for the planning and has modules for the production simulation and real-time shop-floor control. It is operated with a computer network linking the plants at Pindamonhangaba and Sao Caetano do Sul tpo the sales and product areas in Sao Paulo. The culture changing are commented, involving the planning area relationship with other areas, and how personnel commitment with company global objectives. The results show both the improvements in indexes related to productivity and cost reductions, and the better customer services, with more agile and accurate information. (author) 2 refs., 4 figs., 1 tab.

Malere, Ernesto P.; Amaral Carvalho, Sinvaldo do; Correa, Nicolas I.B. [Acos Villares SA, Sao Caetano do Sul, SP (Brazil)

1996-12-31

114

Effect of the microstructure on tribological phenomena occurring on the surface of a mill roll made of SA5T cast iron (GJSL-HV600 - GJSL-330NiMoCr12-8-3)  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with the role of the microstructure in the tribological wear processes occurring in a cast iron mill roll. For this purpose, a piece of a broken roll, made in Italy, was collected. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed on the roll working surface in conjunction with metallographic tests effected within its surface layer. There was established the relation between the microstructure of the roll and the process of its tribological wear. The following was ascertained: micro-shrinkages or graphite precipitations nearby the working area cause cracks between those places and the working area; in the surface layer, cracks occur usually in the zone of ledeburitic cementite. At places of considerable precipitations of ledeburitic cementite, the tribological wear intensity of the roll is lower. A banded layout of precipitations of ledeburitic cementite facilitates a selective spalling of some parts of the roll material. The results of this study allow broadening the data base related to the effect of the microstructure on tribological wear of mill rolls, which in future will permit one to design their proper microstructure of cast iron mill rolls.

J. Krawczyk

2008-01-01

115

Grinding fineness, wear of the grinding surface and energy consumption in the closed-circuit grinding of mineral raw materials  

Energy Technology Data Exchange (ETDEWEB)

As it is not feasible to apply operating results for grinding mills to other commercial plants, investigations were made in a laboratory mill to evaluate fineness, wear and energy consumption with different rocks, ores and wear materials. The wear process in a drum mill was analysed tribologically. Fineness, wear and specific energy consumption increase with mill speed. With increased feed rate there are decreases in fineness and energy consumption but the wear rate increases. The results of the laboratory tests may be applicable to commercial plants under certain circumstances.

Rieger, K.; Clement, M.; Uetz, H.

1982-02-01

116

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)

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.

Yi-Wen Cheng; Patrick Purtscher

1999-07-30

117

Production of CWM with wet type ball mill (part 3). Influence of filled amount of ball and the materials of grinding  

Energy Technology Data Exchange (ETDEWEB)

In the production of CWM (Coal Water Mixture), high concentration is required from the viewpoint of use efficiency. This greatly affects the particle size composition of coal and the selection of the additive. In this report, a wet crushing by means of a compact ball mill was studied on the influence of ball filling and coal charge on the crushing, influence of the ball size, slurry concentration, and amount of slurry, etc.. Result of crushing by a new 100 liter ball mill was compared. In the wet type ball mill, different from the dry crushing, apparent slurry viscosity increases during the crushing and greatly affects the movement of balls and the crushing. From the viewpoint of batch type fine CWM production, for obtaining higher handling capacity and efficiency, it is desirable to crush while the slurry viscosity is adjusted. (6 figs, 3 refs)

Kokubo, Toshimitsu; Sakamoto, Hiroshi; Oya, Hitoshi; Iwata, Hiroyuki; Yamamoto, mitsuru; Fukuda, Takayuki

1988-04-01

118

Dynamic analysis of grinding using the population balance model  

Energy Technology Data Exchange (ETDEWEB)

The dynamic behavior of batch mill, CSTR mill, and a closed grinding network consisting of a mill, sump, and cyclone was analyzed using the dynamic population balance model (PBM). The dynamic solution of the PBM of a batch, CSTR and a closed grinding network consisting of a mill, sump, and cyclone forms the basis of the dynamic analysis presented here. Two numerical dynamic solution approaches were used. These are: (1) providing additional constraints on breakage selection functions or (2) performing the Arbiter-Bhrany (or other) normalization of the selection functions. Actual experimental anthracite batch grinding data was used to obtain the functionality of the batch dynamic mill selection and breakage functions for a real physical system. The Levenberg-Marquardt algorithm for systems of constrained non-linear equations is used to solve the batch dynamic PBM grinding equations to obtain the grinding selection and breakage rate functions. The mill, sump and hydrocyclone were modeled as a CSTR operating at various retention times. Batch dynamic PBM data was used to provide the mill kinetic and breakage selection function data. Different dynamic solutions were obtained depending on the numerical approach used. Each solution approach to a dynamic PBM with transport, while giving the same prediction for a single batch grinding time, gives different solutions or predictions for mill composition for other grinding times. This fact makes dynamic nodal analysis and control problematic. The fact that the constraint solution approach gives a solution may suggest that normalization for closed networks is not necessary. Differences in solutions to the PBM cannot be excused away by inaccuracies in the data used to model the grinding phenomenon.

Williams, M.C. [West Virginia Univ., Morgantown, WV (United States)]|[Particle Analysis Center, Morgantown, WV (United States)

1995-12-31

119

Loads on ball mills and vibrating ball mills  

Energy Technology Data Exchange (ETDEWEB)

Measures to optimize ball mills and vibrating ball mills must be based on detailed knowledge of load mechanisms. A direct method of measurement has been developed to determine the energy distributions of loads transmitted by the grinding balls. The grinding balls are equipped with sensors which measure the frequencies of impact loads and frictional loads transmitted by the ball surfaces in dependence of load intensities. This way, quantitative statements can be made for the first time on load processes in ball mills and vibrating ball mills independent of grinding efficiencies which are also a function of the material to be ground.

Rolf, L.; Vongluekiet, T.; Uygun, M.

1982-06-01

120

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report No. 5, September 1--November 30, 1993  

Energy Technology Data Exchange (ETDEWEB)

Research conducted during the Fifth Quarterly was aimed at the evaluation of the effect of a cationic surfactant, TMAE, on the rheology of coal suspensions and delineation of the effects of anionic, cationic and nonionic surfactants on the aggregation stability of Pittsburgh No. 8 coal-water slurries. The purpose of these studies was to improve the understanding of the behavior of coal-water slurries in the presence of chemical additives.

Fuerstenau, D.W.

1993-12-01

 
 
 
 
121

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report No. 4, June 1--August 1993  

Energy Technology Data Exchange (ETDEWEB)

During the Fourth Quarter, we studied the effect of the initial mixing procedure in the preparation of coal-water slurries, the storage time of ground coal samples, and the addition of anionic surfactants such as 2-TEPA on the rheology of coal-water slurries. The details of these studies are presented in the following paragraphs.

Fuerstenau, D.W.

1993-09-01

122

Investigation of rolling pressure on metallic uranium rod  

Energy Technology Data Exchange (ETDEWEB)

The rolling pressure on metallic uranium rod was investigated. By considering the behavior of the uranium metal in a rolling mill as a viscous flow, the differential equation for the rolling pressure was established. A formula for calculating the rolling pressure was derived and the theoretical calculation method was given. The rolling pressure, the coefficient of contact friction, and the lateral expansion of uranium rod were measured. The measured rolling pressure was compared to the calculated value. Rolling is an important forming technique for uranium. A study of the rolling parameters of uranium serves as a basis for rolling mill design, engineering calculation, and rolling mill strength calibration.

Zhang, M.

1984-06-01

123

Improving energy efficiency of reheating furnace of sheet ingot plant and rolling mill Calibers of Gecamines / Lubumbashi by the recovery of waste heat of smoke  

International Nuclear Information System (INIS)

The economic management of energy is an important topic in industrial processes to the extent that it ensures the competitiveness of any firm and ensures its survival. Within this framework we plan to improve the energy efficiency of the powerful furnace for reheating lingots Rolling Mills and Cable Factory (of which the fuel is diesel) where we propose to install a head recovery exchanger between the hot fumes out of the oven (60 C) and combustion air taken initially at room temperature (250C). Without recovery the oven consumes on the average 101 liters of diesel per hour for its operation and yields a thermal efficiency of 68,6%. Whereas with recovery, it can reach a thermal efficiency of 86% on one of recoverers that we have proposed, and save up to 15,8 liters of diesel on its hourly consumption

2010-01-01

124

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)

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.

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

1998-07-01

125

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)

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.

Rafiei Masoud; Gadgil Alaka; Ghole Vikram; Gore Sharad; Jaafarzadeh Neemat; Mirkazemi Roksana

2009-01-01

126

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.

1040-01-00

127

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)

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.

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

128

Weld-on ceramic tiles to combat abrasive and erosive wear of bowl mill classifier cones  

Energy Technology Data Exchange (ETDEWEB)

Pulverized coal transport equipment such as pipe bends, feed spouts, pulverized housings and classifier cones are rapidly worn out by high-ash, abrasive coals. BHEL has solved these problems by using ceramic tiles (ceralin) to line pipe bends and high density alumina tiles sintered in trapezoid shapes to line classifier cones. These tiles are secured using welding studs. In addition, the service life of the grinding rolls of ball mills has also been improved by the use of a modified Ni-hard type 2 white iron and high chromium iron. 1 fig.

1988-09-01

129

Fine grinding and beneficiation of coal by improved oil agglomeration process  

Energy Technology Data Exchange (ETDEWEB)

Simultaneous grinding and agglomeration in the novel Szego Mill allows significant equipment simplifications and energy savings. The excess grinding energy is used for agglomerate formation. Results obtained with several coals and oils are reported over a range of operating conditions. The economics of coal beneficiation for slurry fuel preparation is considered.

Trass, O.; Campbell, P.D.; Papachristodoulou, G.

1986-01-01

130

Roll Eccentricity Control Using Identified Eccentricity of Top/Bottom Rolls by Roll Force  

Science.gov (United States)

Roll eccentricity is a periodic disturbance caused by a structure of back up rolls in rolling mills, and it affects product thickness accuracy. It cannot be measured directly by sensors, so it should be identified by measured thickness or measured roll force. When there is a large difference of diameters between top and bottom back up roll, the performance of roll eccentricity control using feedback signals of roll force or thickness has not been so good. Also it has been difficult for the control to be applied from the most head end because it is necessary to identify the roll eccentricity during rolling. A new roll eccentricity control has been developed to improve these disadvantages and to get better performance. The method identifies top and bottom roll eccentricity respectively from one signal of roll force and it can start the control from head end. In this paper the new control method is introduced and actual application results to a hot strip mill are shown.

Imanari, Hiroyuki; Koshinuma, Kazuyoshi

131

Study concerning the grinding of the glazes for porcelain obtained by fast firing  

Energy Technology Data Exchange (ETDEWEB)

In present paper there is examined the stage grinding of glazes used for glazing feldspar porcelain under conditions of advanced technology of ceramic industry. There are proposed corresponding solutions of achieving an adequate operation for each milling stage. (orig.)

Teoreanu, I. [Universitatea Politehnica, Bucharest (Romania); Dumitrache, R.L. [S.A. ARPO, Curtea de Arges (Romania)

2002-07-01

132

ONLINE SAG MILL PULSE MEASUREMENT AND OPTIMIZATION  

Energy Technology Data Exchange (ETDEWEB)

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.

Raj Rajamani; Jose Delgadillo; Vishal Duriseti

2006-06-24

133

Outogenius! The testing of autogenous grinding in laboratory and pilot scale, and the design of full scale comminution circuits  

International Nuclear Information System (INIS)

[en] The design of autogeneous grinding mills is difficult because of the variability of their grinding media; when steel balls or rods are used as in SAG or non-autogenous machines, calculations can be much more reliable because--obviously--the characteristics of the media are constant, or predictable. But when the grinding medium and the feed material are one and the same thing, the variations in the physical characteristics of the feed multiply the design problems, especially in the case of autogenous primary mills. Now, however, researchers from Outokumpu, Finland, working backwards after years of studying full scale autogenous production mills, are developing a special laboratory method to test the suitability of ores for Outogenius comminution, Outokumpu's own autogenous grinding process. This paper discusses the results of these new grinding machines which use ores to grind ores. The specifications of the machinery are provided along with the performance on various types of ores

1993-01-01

134

Characteristics of wet grinding of highly concentrated coal water slurry  

Energy Technology Data Exchange (ETDEWEB)

In an effort to provide basic data helpful for production of highly concentrated coal water slurry, the wet grinding characteristics of coal water mixtures (CWMs) at high concentrations are investigated by conducting batch preparation tests using a laboratory-scale ball mill. For the tests, 12 different coal samples are employed together with three anonic dispersing agents. measurements show that the use of a dispersion agent can greatly increase the wet grindability of highly concentrated CWMs. This is attributable to improved movements of the balls due to a decrease in the apparent viscosity at low shear rates. Different types of coal show widely different grindabilities, which is attributed to the differences in flocculation force of coal particles. As to the particle size distribution, high-concentration wet grinding is characterized by a larger content of fine particles compared to wet grinding or low-concentration wet grinding. (13 figs, 4 tabs, 3 refs)

Ito, Hayami; Tatsumi, Shuhei; Kajibata, Yoshihiro; Takao, Shoichi; Ozaki, Hironori; Katahata, Tadashi

1988-03-10

135

Photoacoustic study of nanocrystalline silicon produced by mechanical grinding  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-04-01

136

MODELING THE ENERGY REQUIREMENTS OF FIRST-BREAK GRINDING  

Science.gov (United States)

The influence of roller mill gap and single kernel properties of wheat on the energy requirements of first-break grinding was studied. Multiple linear regression models for energy per unit mass (EM), new specific surface area (ANSS, in log scale), and specific energy (EA = EM /ANSS) were developed ...

137

Slave to the grind  

Digital Repository Infrastructure Vision for European Research (DRIVER)

1. Monkey business / Bolan - Snake + 2. Slave to the grind / Bach - Bolan - Snake + 3. The threat / Bolan - Snake + 4. Quicksand Jesus / Bolan - Snake + 5. Psycho love / Bolan + 6. Get the fuck out / Bolan - Snake + 7. Livin' on a chain gang / Bolan - Snake + 8. Creepshow / Affuso - Bolan - Snake + ...

Skid Row

138

Efficient grinding of cellulosic fibers for use as plastics fillers  

Energy Technology Data Exchange (ETDEWEB)

Grinding of waste paper and rice hulls for use as reinforcing plastics fillers was studied using the proprietary Szego Mill in open circuit grinding as well as in combination with a high capacity classifier. Newsprint, office paper and glossy magazine paper have been used. Some test specimens were prepared with and without coupling agent and their properties measured. The importance of filler particle size on the mechanical properties of the product depends on the means used to compound paper and the plastic. In order to ensure good handling characteristics of the paper fibers during storage, feeding and subsequent molding, it is necessary to control both particle shape and top size. The Szego Mill product is relatively easy to feed and handle along with good size range control. Particle size distribution and bulk density of the products were determined after grinding and classifying under different operating conditions. Mill capacity and specific energy consumption depend strongly on particle size distribution of the feed and the desired top size of the product. For a rough estimate of mill and classifier performance, a production rate of 220 kg/h was reached while reducing newsprint particle size from 3,000 {micro}m to < 425 {micro}m in the SM-320 mill. Specific energy consumption was typically around 80 kWh/t.

Moelder, T.; Trass, O. [Univ. of Toronto, Ontario (Canada). Dept. of Chemical Engineering and Applied Chemistry

1995-10-01

139

Collective grinding of plastic materials at temperatures below 273 K  

Energy Technology Data Exchange (ETDEWEB)

The total energy requirement for low temperature grinding essentially depends on the solids precooling temperature. In order to determine an energetically favourable precooling temperature the influence of temperature on the energy requirement for grinding and on the result of comminution was investigated experimentally. The test facility consists of a pinned disk mill and devices for cooling the feedstock and the mill gas. Polyethylene (PE) and cellulose acetobutyrate (CAB) were chosen as test materials. The investigation was based on the idea, that a multiple cooling and grinding at less reduced temperatures could result in lower energy requirement than single passage grinding at very low solids precooling temperature Tsub(S,) sub(V). Grinding proved to be feasible only below the glass transition temperature Tsub(g) (PE: Tsub(g) approx.= 190 K; CAB: Tsub(g) approx.= 258 K). The total energy requirement of the test plant is calculated by means of an energy balance, depending on the solids precooling temperature. The results show an energetic minimum at temperatures above Tsub(S,) sub(V) = 77 K.

Petersen, H.; Schwedes, J.

1984-05-01

140

Finite element analysis of deflection of rolls and its correction by providing camber on rolls  

Directory of Open Access Journals (Sweden)

Full Text Available Rolling process is a key step in the production of flat steel products. Because of automation commonly implemented in flat product rolling mills, the products should meet the requirements of tight tolerances. one of the major defects observed in the rolling process is flatness and lack of attainment of the desired surface profile due to deflection of the rolls. The spatial shape and dimensions of the roll gap are influenced by the elastic deformation of all parts of the rolling stand equipment affected by the roll pressure. The current study aims to determine the variation of the deflection in rolls in a two high mill with varying percentage reduction of the sheet i.e, 20%, 25% and 30% on annealed and non-annealed IF steel sheet and analyzing possible solutions to reduce the elastic deflection of rolls with special emphasis on cambering and modelling of the same in Abaqus CAE.

Vijay Gautam

2013-01-01

 
 
 
 
141

Roll force, torque, lever arm coefficient, and strain distribution in edge rolling  

Science.gov (United States)

Due to the growing importance of width control in strip and plate mills, edge rolling is currently an im-portant process in hot rolling mills. Research in edge rolling has been carried out, and in the present ar-ticle, models for roll force, torque, and lever arm coefficient are derived using the upper bound method. A simple, kinematically admissible deformation zone and velocity field, independent of friction in the roll gap, is proposed, and the energy dissipation rate is derived. The formula for energy dissipation rate has, in practice, no limitation because all edge rolling geometries are safely in the area where the formula is valid. Roll force and torque are derived by means of two independent integrals. Thus, the lever arm coef-ficient is evaluated from the expressions for roll force and torque using conventional rolling theory. Roll-ing trials report good agreement with theory. Measured roll forces are similar to calculated forces. Furthermore, the shape of the dogbone that arises during edge rolling is in fairly good agreement with the calculated dogbone shape. Deviations are due to the deviation from ideally plastic material in the ex-periments. Also, the strain distribution over the dogbone is similar to the proposed deformation zone. Thus, a new formula has been developed to a stage that it can be implemented in width control systems for edge rolling stands in hot strip and plate mills.

Lundberg, S.-E.; Gustafsson, T.

1993-12-01

142

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

Science.gov (United States)

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 a...

J. Mengel A. Martocci L. Fabina R. Petrusha R. Chango P. Angelini V. Sikka

2003-01-01

143

Pilot-industrial technology of sintered tungsten bar section rolling  

International Nuclear Information System (INIS)

Results of development and industrial introduction of new technology for rolling of bar sections from sintered tungsten on specialized rolling mill MK-380 with four-high passes of the Chelyabinsk Polytechnical Institute design are given. The rolling mill design is described and recommendations are given as to the working roll materials. The new technology is characterized by a higher output and quality of produced sections in comparison with existing methods of processing

1984-01-01

144

Pilot-industrial technology of sintered tungsten bar section rolling  

Energy Technology Data Exchange (ETDEWEB)

Results of development and industrial introduction of new technology for rolling of bar sections from sintered tungsten on specialized rolling mill MK-380 with four-high passes of the Chelyabinsk Polytechnical Institute design are given. The rolling mill design is described and recommendations are given as to the working roll materials. The new technology is characterized by a higher output and quality of produced sections in comparison with existing methods of processing.

Vydrin, V.N.; Barkov, L.A.; Pastukhov, V.V.; Matveev, V.A.; Mebel' , V.S. (Chelyabinskij Politekhnicheskij Inst. (USSR))

1984-12-01

145

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)

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.

Mengel, J.

2003-12-16

146

Surface Fine Grinding via a Regenerative Grinding Methodology  

International Nuclear Information System (INIS)

[en] This paper presents a regenerative surface fine grinding methodology to remove grinding defects of traditional operations and to improve the quality of surface flatness. All possible surface defects produced by traditional and creep-feed grinding operations are carefully reviewed and circumvented. These defects include non -uniform traces, pitting spots, scratches, burnouts, and quenching breakage. To alleviate these traditional grinding defects, the paper presents a new approach by designing and constructing a regenerative surface fine grinding system that includes a mechanism that carries the submerged workpart in an oil-contained open box. The fine grinding tool held by the spindle-chuck unit of the CNC machine is moved in relative to the workpart surfaces by a combined trajectory of a cycloid path, a linear feed and a lateral travel. Some numerical simulations for selecting appropriate grinding trajectories are presented and simulated. The trajectory is selected based upon the resulting quality of contact uniformity and homogeneity as expressed in terms of contact frequency to each point on the workpart surface. The simulation model is then used to characterize appropriate working range of each grinding parameter. Different grinding paths are thus generated and superposed. A working machine is designed and built based upon the simulation results. Several experiments are carried out on the constructed grinding system with the grinding tool mounted to the spindle-chuck unit of the CNC machine. The surface quality of the ground workpart is measured. Tests on different system parameters demonstrate the importance of choosing the correct grinding wheel and grit size and an illustration of the proper selection of process and system parameters are presented. The experimental results are compared with those of analytical solutions. Good agreement between them is observed. In ninety minutes fine-grinding operations using the proposed method, the workpart surfaces generally possess no damage and surface roughness is reduced to the range of 0.02?0.04?m in Ra. To verify the effectiveness of the proposed method, the results of fine grinding operations using various process parameters are measured and recorded. The effects of various combinations of process parameters including trajectory density, uniformity and grinding efficiency on the effect of surface flatness enhancement are carefully examined and concluded

2006-01-01

147

Calucaltion of waste heat from hot rolled steel coils at SSAB and its recovery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hot rolling process is heat input process. The heat energy in hot rolled steel coils can be utilized. At SSAB Strip Product Borlänge when the hot rolled steel coils came out of the hot rolling mill they are at the temperature range of 500°C to 800°C. Heat energy contained by the one hot rolled steel...

Yousaf, Naeem

148

Effects of grinding on certain crystalline structures  

International Nuclear Information System (INIS)

[en] 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)[fr] 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 (?) 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)

1965-01-01

149

Trends in development of impact mills  

Energy Technology Data Exchange (ETDEWEB)

This paper investigates parameters of the grinding process in impact mills by experiments conducted on a laboratory mill with rotor diameter of 150 mm and a maximum throughput of 12 kg/h, and on a semi-industrial mill with impact rotor diameter of 500 mm and throughput of 1.65 ton/h. The mill type is employed for materials with a hardness below 3 or 4 on the MOHS scale; the material being ground may also be moist, and high throughput can be achieved with a relatively small mill size. Experiments study the grinding effect by determining the specific surface according to Blaine, ranging between 2,000 and 4,000 cm/sup 2//g, and the required size reduction energy for selected rotor rotation rates. The size reduction energy is calculated taking energy losses in the grinding process into account. It was found that a high throughput is required for reducing the energy requirement of the mill. Two exponents were further derived for determining power requirement relations of the mill. The formula for the mill's power requirement is explained. It enables the optimum mill design and mill operation parameters to be selected and can be used for issuing operation standards by mill producers.

Goldacker, H.; Hoeffl, K.; Husemann, K.

1981-01-01

150

Design of the Soymilk Mill based on TRIZ Theory  

Directory of Open Access Journals (Sweden)

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.

Jiang Fan; Wang Yijun; Xiang Jianhua; Huang Chunman

2013-01-01

151

Grinding mechanism of zirconia toughened alumina  

International Nuclear Information System (INIS)

[en] In the grinding process, physical properties of ceramics affect both grinding mechanism and quality of ground surface. In this study we focused on fracture toughness of ceramics and the effect on grinding. A grinding test was carried out by single point grinding for ten different zirconia toughened alumina ceramics with different monoclinic zirconia contents. Effects of zirconia contents on the grinding mechanism and crack initiation were discussed. Copyright (1998) AD-TECH - International Foundation for the Advancement of Technology Ltd

1998-01-01

152

Numerical modeling of grinding rate in granular flow of brittle materials  

Energy Technology Data Exchange (ETDEWEB)

In a iron-making blast furnace, the operation with pulverized coal injection (PCI) causes accumulation of powder, attributed to an unburned char and a ground coke, and then the permeability through the coke bed in the furnace would be decreased. It is so difficult to measure a mount of powder divided up into an unburned char and a ground coke, that the authors have developed numerical simulation models to estimate the grinding rate in granular flow of brittle material, such as coke and gypsum. In the simulation the particle motion is analyzed by the Distinct Element Method (DEM). The grinding rate of particles is calculated by the experiment equation, which is formulated on the basis of mutual friction of grinding test. To examine the simulation models in this study, the authors analyze the motion of particles and estimate the grinding rate in a small drum mill. The estimated particle flow pattern and the grinding rate are similar to observed.

Kitamura, Y.; Ogawa, M.; Tsuge, H.; Furuhata, T.; Miura, T. [Tohoku Univ., Sendai (Japan). Dept. of Biochemistry and Engineering

1996-12-31

153

High efficiency dry-grinding plants for coal  

Energy Technology Data Exchange (ETDEWEB)

When dust firing cement kiln plants the raw hard coal has normally to be pulverised to a fineness of 90% passing 90[mu]m and to be dried to a residual moisture of 1%. Most modern cement kiln plants are equipped with burners suitable for different types of coal or coal mixtures. The central grinding plants offered by Claudius Peters can meet these requirements with minimum heat consumption, the main system part being the EM-ball-ring-mill. The article describes the mode of operation of the EM-mill and its advantages in terms of efficiency, maintenance and resistance to foreign matter. 3 figs.

Floeter, H.-J.; Thiel, J.-P. (Claudius Peters AG, Hamburg (Germany))

1992-07-01

154

Preparation of coal slurry fuels with the Szego mill  

Energy Technology Data Exchange (ETDEWEB)

Performance data for the wet grinding of coal have been obtained in this novel, planetary ring-roller mill over a wide range of operating conditions. Results from mills of different sizes are presented, with rotational speed, feed rate, coal loading in oil and water, type of coal and residence time in the mill as the main variables. Combining empirical results with insight of mill dynamics has allowed a design capacity scale-up from 0.5 to 20 + t/h coal. The mill is able to grind coal and other materials down to the ultrafine 10 ..mu..m size range rapidly and efficiently.

Gandolfi, E.A.J.; Papachristodoulou, G.; Trass, O.

1984-10-15

155

FORTRAN program for the calculation of Bond's grinding work index  

Energy Technology Data Exchange (ETDEWEB)

The present study represents the algorithm using Fortran language in order to simplify the previous method for the calculation of the Bond's grinding work index. The primary data used in this algorithm, such as particle size of ground product and circulation load, make possible the simultaneous calculation of the stable revolution number of mill, the grindability, and the grinding work index. The procedure for the data inputs and calculations is minimized by 93 percent and is stable, hence to yield better grinding work index than that of the previous method with problems of increasing cycle number originated from its complex calculation nature. (author). 12 refs., 2 tabs., 2 figs.

Sim, Chol-Ho [Sangji University, Wonju(Korea); Oh, Seung-Kyo [Konyang University, Nonsan(Korea)

2000-10-31

156

Autogenous grinding for bath scraps recycling  

Energy Technology Data Exchange (ETDEWEB)

In the early 80`s, FCB designed an original process for the recycling of bath scraps in Aluminum smelters, using a single stage fully air-swept autogenous mill. Since then, the 9 industrial references confirmed and even exceeded the expectation in terms of dust-free and easy to run operation, high recovery ratio of bath among the metallic scraps, and low maintenance cost. Problems encountered on conventional processes belong to the old days, and new projects tend to give an increasing importance to classification and storage of crushed products, autogenous grinding being already recognized as the most suitable, simple and reliable process route. The present paper describes this original process and draws up the overall performances of ten years of experience.

Pinoncely, A.; Podda, P. [FCB, Givors (France). Mineral Processing and Carbon Plant Div.

1996-10-01

157

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

International Nuclear Information System (INIS)

[en] 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)

2005-01-01

158

Prediction of work-roll temperature distribution in continuous hot strip rolling process  

Energy Technology Data Exchange (ETDEWEB)

Prediction of temperature distribution within the work-rolls during the hot slab rolling process is of great importance to mill designers. This is because, not only the temperature distribution in rolling material and the dimensional accuracy are depended on work-roll temperature but also the roll life is a function of its temperature distribution. In this paper using the heat transfer equations for moving media and a two dimensional finite element method, the work-roll temperature distribution during continuous hot strip rolling process is predicted. To achieve an accurate temperature field the effects of various factors including the rolling speed, interface heat transfer coefficient, and the amount of slab thickness reduction at each deformation pass are taken into account. Comparison between the predicted and experimental published results depicts the validity of the mathematical model. (author)

Karimi Taheri, A.; Serajzadeh, S. [Sharif University of Technology, Dept. of Material Science and Engineering, Tehran (Iran, Islamic Republic of); Shahriari, M.A.; Izadi, J.; Fattahi, M. [Mobarake Steel Complex, Isfehan (Iran, Islamic Republic of)

2000-07-01

159

Prediction of work-roll temperature distribution in continuous hot strip rolling process  

International Nuclear Information System (INIS)

Prediction of temperature distribution within the work-rolls during the hot slab rolling process is of great importance to mill designers. This is because, not only the temperature distribution in rolling material and the dimensional accuracy are depended on work-roll temperature but also the roll life is a function of its temperature distribution. In this paper using the heat transfer equations for moving media and a two dimensional finite element method, the work-roll temperature distribution during continuous hot strip rolling process is predicted. To achieve an accurate temperature field the effects of various factors including the rolling speed, interface heat transfer coefficient, and the amount of slab thickness reduction at each deformation pass are taken into account. Comparison between the predicted and experimental published results depicts the validity of the mathematical model. (author)

2000-01-01

160

Two component grinding and liberation model and experimental studies of Cryogenic Tar Sand Separation  

Energy Technology Data Exchange (ETDEWEB)

Cryogenic Tar Sand Separation is a novel technique to access the vast energy potential of the Alberta Tar Sands. In this process tar sand is ground at about -50/sup 0/C. At this temperature the tar is more brittle and weaker than the sand. Thus, the tar is liberated from the sand and ground to fine particles, which can be separated from the sand. The technical performance of this process was studied, and a general grinding and liberation model was developed, which simulates this and two other component grinding processes. Four grinding/separation techniques were studied: Fluidized Bed Grinder (a stirred fluidized bed with steel balls) and Spouted Bed grinding combined with tar entrainment, and High Speed Impeller and Ball Mill grinding combined with sieving. The spouted bed gave the highest quality of separation, with a tar purity of 84%, at a tar recovery of 90%. The ball mill gave the lowest separation quality with a tar purity of 60% at 80% tar recovery, and 35% of 90% recovery. A maximum tar recovery of 94%, at a tar purity of 65%, was obtained in the fluidized bed grinder. The spouted bed gave the lowest rate of separation, with a typical processing time of 14 hours to obtain 90% tar recovery, versus 2-7 hours for the other mills. However, proposed modifications should increase this rate substantially.

Welmers, A.

1983-01-01

 
 
 
 
161

Spray Rolling Aluminum Strip for Transportation Applications  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-02-01

162

Preparation of coal-oil mixtures for combustion by continuous grinding of coal in oil  

Energy Technology Data Exchange (ETDEWEB)

This study was undertaken to obtain performance data for grinding coal in oil with existing small Szego mills, to design, build, and test a larger prototype unit, to establish empirical scale-up parameters from the results, and to prepare a functional design of a commercial size mill for industrial or boiler use. The methodology by which these goals was undertaken is described. 10 refs., 14 figs., 13 append.

Trass, O.

1982-06-01

163

Effect of grinding conditions on the structure and physicomechanical properties of hot-pressed boron carbide  

Energy Technology Data Exchange (ETDEWEB)

The properties of boron carbide powders ground in a planetary mill are compared with those of commercial boron carbide powders produced by other methods. It is shown that the grinding of coarse boron carbide in a planetary mill makes it possible to produce high-density powder compacts with a homogeneous structure and a high strength. The strength of the compacts increases with decreasing grain size and approaches that of the material produced by more complex processes. 8 references.

Koval' chuk, V.V.; Kotliar, D.A.; Volkogon, V.M.; Timchenko, R.G.; Lychko, V.V.

1988-12-01

164

Online SAG Mill Pluse Measurement and Optimization  

Energy Technology Data Exchange (ETDEWEB)

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.

Raj Rajamani; Jose Delgadillo; Vishal Duriseti

2007-06-30

165

The cryogenic grinding as the important homogenization step in analysis of inconsistent food samples  

UK PubMed Central (United Kingdom)

Some homogenisation approaches have been investigated to make easier and overcome troublesome preparation of inconsistent food samples. Contents of Na, Ca, Mg, P, Fe, Mn and Zn in muesli, seed and instant food samples were determined by inductively coupled plasma optical emission spectrometry after their grinding with an agate mortar, a kitchen coffee grinder and a cryogenic mill. The efficiency of a grinding step was evaluated using RSDs and homogeneity factors (H-factor). For cryogenically grinded samples, RSDs were detected about 4% and H-factors on 10, what is acceptable for the analytical purpose. The results for grinding with an agate mortar as well as a coffee grinder were quite unsatisfactory (RSDs in tens percent). Differences between RSDs and H-factors for the procedures tested were detected to be statistically significant. Different element contents were observed in differently treated samples which is probably a result of an unevenly element distribution in inhomogeneous components forming sample.

Krej?ová Anna; Pouzar Miloslav; ?ernohorský Tomáš; Pešková Kv?ta

2008-08-01

166

Modified oil agglomeration for coal beneficiation. 2. Simultaneous grinding and oil agglomeration  

Energy Technology Data Exchange (ETDEWEB)

The spherical oil agglomeration technique developed at the National Research Council of Canada (NRC) for cleaning and recovering very small coal particles can be simplified by combining the grinding and agglomeration steps such that the excess energy expended while grinding is used for mixing and agglomeration. Experiments with the Szego mill, which is able to handle the pasty agglomerates, have shown that ash removal from Minto (New Brunswick) coal is comparable to that obtained with the usual NRC process. The generally flaky products of the Szego mill allow better ash liberation, and the presence of oil enhances grinding performance. Favourable oil-coal-water ratios have been established. Major savings in equipment and operating costs are possible with the combined process. 12 refs., 7 figs.

Trass, O.; Bajor, O.

1988-04-01

167

Moessbauer studies of the phase decomposition process of YFe2 by mechanical grinding  

International Nuclear Information System (INIS)

[en] Mechanically ground YFe2 was studied by means of X-ray diffraction and Moessbauer effects. It is shown that YFe2 decomposes into amorphous Y-Fe and bcc Fe on mechanical grinding. Milling time dependence of the fraction of Fe atoms in each state is determined by Moessbauer analyses. (orig.)

1993-01-01

168

High speed abrasive belt grinding  

Science.gov (United States)

A project was established to reduce current stock removal costs and eliminate finish turning operations of tubes by combining rough stock removal and finish grinding. The first phase was designated for engineering and investigation into the feasibility and application of abrasive belt grinding technology. This information was then used to generate a specification establishing some criteria for design and manufacture of a machine to remove heavy stock and finish tubes using abrasive belt technology. The specification was subsequently used for the acquisition of a machine to perform the tasks. The second phase was designated for testing of the equipment and establishing production parameters.

Bak, Joseph

1989-01-01

169

Developments in precision optical grinding technology  

Science.gov (United States)

Optical systems that utilize complex optical geometries such as aspheres and freeform optics require precise control through the manufacturing process. As the preparatory stage for polishing, this is especially true for grinding. The quality of the grinding process can greatly influence the polishing process and the resultant finished product. OptiPro has performed extensive development work in evaluating components of a precision grinding machine to determine how they influence the overall manufacturing process. For example, spindle technology has a strong effect on how a grinding machine will perform. Through metrology techniques that measure the vibration characteristics of a machine and measurements of grinding forces with a dynamometer, OptiPro has also developed a detailed knowledge of how the machine can influence the grinding process. One of the outcomes of this work has led OptiPro to develop an ultrasonic head for their grinding platform to aid in reducing grinding forces. Initial results show a reduction in force by ~50%.

Fess, Edward; Bechtold, Mike; Wolfs, Frank; Bechtold, Rob

2013-09-01

170

The rolling tachyon as a matrix model  

International Nuclear Information System (INIS)

We express all correlation functions in timelike boundary Liouville theory as unitary matrix integrals and develop efficient techniques to evaluate these integrals. We compute large classes of correlation functions explicitly, including an infinite number of terms in the boundary state of the rolling tachyon. The matrix integrals arising here also determine the correlation functions of gauge invariant operators in two dimensional Yang-Mills theory, suggesting an equivalence between the rolling tachyon and QCD2. (author)

2003-01-01

171

Nanozeolite Produced by Wet Milling at Different Milling Time  

Science.gov (United States)

Recently, there has been a considerable growing interest in utilizing nanozeolites due to their advantages over conventional micron sized materials. Zeolite particle may be reduced by mechanical treatment such as ball milling or grinding in order to get smaller particles. In this paper, effect of milling time on particle size and surface morphology of Zeolite were investigated by a few designed of experiments in aqueous environment. Zeta-sizer Nano series of particle sizer and Field Emission Scanning Electron Microscopy (FESEM) have been used to characterize this nanozeolite. Results shown that, there were changes of particle size and also the surface morphology of Zeolite.

Mukhtar, N. Z. F.; Borhan, M. Z.; Abdullah, S.; Rusop, M.

2013-06-01

172

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

International Nuclear Information System (INIS)

[en] 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

2000-01-01

173

Mill’s Perfectionism  

Directory of Open Access Journals (Sweden)

Full Text Available J. S. Mill lays great emphasis on the importance of the notion of theindividual as a progressive being. The idea that we need to conceive the self as an object of cultivation and perfection runs through Mill’s writings on various topics, and has played a certain role in recent interpretations. In this paper I propose a specific interpretation of Mill’s understanding of the self, along the lines of what Stanley Cavell identifies as a “perfectionist” concern for the self. Various texts by Mill, ranging from the Logic to On Liberty, show an understanding of the self in which both the theoretical and the practical domain are presented as being internally connected to the transformation of the self. Mill elaborates a criticism of a notion of truth articulated by doctrines having a life independent of the self, as well as a notion of choice which is not the expression of one’s inner self. This internal relation of truth and choice to the self generates a special dialectic within the self, which Mill explores in On Liberty’s second and third chapters by means of several contrasts, such as passive vs. active knowledge, living vs. dead beliefs, or being oneself vs. liking and choosing in crowds.

PIERGIORGIO DONATELLI

2006-01-01

174

Maximizing wear resistance of balls for grinding of coal  

Energy Technology Data Exchange (ETDEWEB)

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.

Albertin, E.; de Moraes, S.L. [Technology Research Institute IPT, Sao Paulo (Brazil)

2007-09-15

175

Influence of the charge properties on the milling tools wear during intensive milling in liquid environment  

Directory of Open Access Journals (Sweden)

Full Text Available Grinding belongs to the basic technological operations in the treatment and processing of minerals. The method of the intensive grinding in a liquid environment has become attractive for the preparation of technologically advanced materials of the high fineness. Its choice was motivated by the intensification of dispersion and by the protection of ground powder against oxidation. The result of energy and material interactions among the grinding media and grinding environment is the wear of the grinding media and contamination of the ground material. The hardness of the particles has an important influence on the rate of wear. Particles with hardness lower than that of the surface of milling tools cause much less wear than harder particles. The wear rate becomes much more sensitive to the ratio of the abrasive hardness Ha to the surface hardness Hs when Ha/Hs <¡­1.The paper deals with the influence of four minerals with various microhardness (corundum, quartz, silicon and magnesite) on the steel milling tools wear during intensive milling.. Experiments were performed in a vibration mill in methanol under same conditions. The grinding time was changed in a geometric sequence from 0,125 to 4 hours. The newly created surface area providesa basic information on grinding. The specific surface area was determined by the standard Brunauer-Emmett-Teller (BET) method using the appratus Gemini 2360 (Sylab, Austria). The concentration of iron was determined by AAS (SpectrAA-30, Varian, Australia). It was confirmed that the rate of ball wear depends on the hardness of feed materials. It was found that the relation between the contamination of the ground powders by wear and the specific surface area increment is linear and the slope depends on the microhardness of the ground material.

Bálintová Magdaléna; Števulová Nadežda

2002-01-01

176

Techniques and relative energy requirements for fine-coal grinding  

Energy Technology Data Exchange (ETDEWEB)

The Coal Grinding Task Group basically characterized coal grinding technology (June 1982) with an emphasis on identifying any needs related to producing very fine coal (<325 mesh). The underlying assumption was that future coal usage in non-designed-for-coal-applications will depend on coal being free of ash (and perhaps sulfur), or capable of behaving in a fluid-like manner, or both. One common step toward both of these attributes is the fine grinding of coal. Of the various types of fine grinding devices identified, two were found to appear superior from the standpoints of energy consumption and operational lifetime. These are the attritor (a special embodiment of which is the Drais Direct Dispersion System), and the Fluid Energy Reduction Mill. There are two widely regarded theories that relate energy consumption to product particle size. The first was developed by Rittinger about 1867 and holds that, ''The work required to reduce particle size is directly proportional to the new surface area produced.'' The second theory, developed by Kick in 1885, was based on plastic deformation, ''The work required for crushing a given quantity of material is constant for the same reduction ratio, irrespective of the original size.'' Neither of these theories has been found to be exactly applicable; however, the Rittinger theory appears reasonably usable in the range of 10 to 100 microns. The Kick theory appears better matched to larger particle sizes. Another approach, known as the Bond theory, fits between the two. The conclusion is that cost, scale of available hardware and technology, and the ability to make reliable predictions relative to producing any UCCWM that requires particles below the 10-micron size should be approached with great caution.

Notestein, J.E.

1982-05-01

177

Manufacturing of molybdenum tubes by pressing and skew rolling  

Energy Technology Data Exchange (ETDEWEB)

A study was made on the quality of tube billets and molybdenum cast tubes, manufactured by pressing and the following skew rolling. The structure of the device for increasing the stability of exit side of screw rolling vacuum mill is suggested.

Kozeradskij, S.A.; Kravchenko, S.G.; Pravikov, V.A.

1982-04-01

178

Investigation of AE Features in Grinding  

International Nuclear Information System (INIS)

[en] This paper presents recent investigation of acoustic emission (AE) behaviours in grinding processes. It demonstrated the acoustic emission features characterized in time and frequency domain are influenced by thermal behaviours of materials. By control laser conditions, the temperature elevation under laser irradiation can be similar to that in a grinding process. Therefore, an innovative concept that grinding process can be monitored by using thermal AE signatures from laser irradiation tests has been proposed. Accordingly, an artificial neural network (ANN), built on laser irradiation tests, was applied to monitor grinding thermal performance. The results showed that grinding performance variation due to wheel wear can be identified by using the ANN. This development could bring great benefits by reducing experimental works in the preparation of an ANN for grinding monitoring.

2012-05-28

179

Modern coal mill design and performance  

Energy Technology Data Exchange (ETDEWEB)

In this paper, a brief description of some of the recent developments in the design and operation of large vertical spindle, ball and ring coal mills within Mitsui Babcock Energy Limited are described. These developments include: the employment of the Mini-mill test Facility at Mitsui Babcock Technology Centre in Renfrew, Scotland for mill development and coal characterisation work; a summary of some recent testwork on the milling characteristics of coal blends; the developments in the design of mill grinding elements and mill operation for the milling of highly abrasive coals; the developments in mill throat and classifier design; the development and implementation of mill upgrades; and a description of the 8E mill series. The material presented in the paper represents a report of work in progress. The development of large coal mills within MBEL is a process of continuous improvement, directed at ensuring that the mill product range offered by the company is commercially competitive in world markets, and can respond to changes in coal types and customer requirements. 13 figs., 3 tabs., 1 plate.

Livingston, W.R.; Dugdale, K.L. [Mitsui Babcock Energy Limited, Renfrew (United Kingdom)

1998-12-01

180

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.

2012-05-28

 
 
 
 
181

30 CFR 77.401 - Stationary grinding machines; protective devices.  

Science.gov (United States)

... 2009-07-01 false Stationary grinding machines; protective devices. 77...Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit...

2009-07-01

182

30 CFR 56.14115 - Stationary grinding machines.  

Science.gov (United States)

...2009-07-01 2009-07-01 false Stationary grinding machines. 56.14115 Section 56.14115...Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders,...

2009-07-01

183

30 CFR 75.1723 - Stationary grinding machines; protective devices.  

Science.gov (United States)

... 2009-07-01 false Stationary grinding machines; protective devices. 75...Miscellaneous § 75.1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit...

2009-07-01

184

30 CFR 57.14115 - Stationary grinding machines.  

Science.gov (United States)

...2009-07-01 2009-07-01 false Stationary grinding machines. 57.14115 Section 57.14115...Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders,...

2009-07-01

185

Manufacturing processes 2 grinding, honing, lapping  

CERN Multimedia

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).

Klocke, Fritz

2009-01-01

186

Precision diamond grinding of ceramics and glass  

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-12-01

187

Delamination of hexagonal boron nitride in a stirred media mill  

Energy Technology Data Exchange (ETDEWEB)

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 ZrO{sub 2} 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 ZrO{sub 2} 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{sup -1} showing that the in-plane order in the milled platelets is remained.

Damm, C., E-mail: cornelia.damm@fau.de; Koerner, J.; Peukert, W., E-mail: Wolfgang.Peukert@lfg.fau.de [University Erlangen-Nuremberg, Institute of Particle Technology (Germany)

2013-04-15

188

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.

2013-01-01

189

High-speed milling of light metals  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Purpose of this paper: Introduction applicability of high-speed cutting of light metals is presented inthis paper.Design/methodology/approach:HSC is the result of numerous technical advances ensuring that milling hasbecome faster than conventional milling and has gained importance as a cutting process. The advantages ofthe HSC milling are higher productivity owing to the reduction of machining times increase of the flow timeof production, reduction of the number of technological operations, increase of the surface quality and longerservice 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 theautomobile, aircraft and electronic industry and in the manufacture of various mechanical parts. Also theachievements in the area of building of machines and tools, ensuring high cutting speeds (highly efficientmachining) have contributed to development of the process.Research limitations/implications: High quality of the surfaces, the quality of this so-called HSC milling canbe compared to grinding.Practical implications: High-speed milling of light metals from aluminium and magnesium is more and morefrequently used in practice. This result is high quality of the surface and shorter machining times. In some caseswhen machining by grinding is specified, the latter is omitted.Originality/value: The applicability of high-speed milling has proved to be successful, when aluminum andmagnesium alloying materials are machined.

F. Cus; U. Zuperl; V. Gecevska

2007-01-01

190

Differential comminution of gypsum in cements ground in different mills  

International Nuclear Information System (INIS)

Identical mixes containing fixed amounts of ordinary Portland cement clinker and gypsum were ground in two types of industrial cement mills - viz. ball mill (BM) and vertical roller mill (VRM) - to identical Blaine fineness to examine the effect of any possible differential comminution of gypsum on cement setting times. The present investigation demonstrates that during comminution of cements, the degree of crystallinity of gypsum, as determined by X-ray diffraction (XRD), changes with used grinding mills and this causes changes in setting times of similar cements even when ground to identical Blaine fineness

2003-01-01

191

Low specific-grinding energy machining of ceramics by a laser dressed diamond grinding stone  

International Nuclear Information System (INIS)

[en] A laser dressing is an effective dressing method to accomplish efficient ceramic grinding. Since laser dressing achieves protrusion heights of abrasive-grains without grain dislodgment, the number of abrasive-grains in a laser dressed grinding stone (LGS) is higher than that in a mechanically dressed grinding stone (MGS), remaining the initial grain distribution. Thus, the LGS contains higher number of effective cutting edges, and forms higher number of ground grooves on a ground surface than the MGS. Consequently, the LGS can achieve lower specific grinding energy than the MGS. Copyright (2003) AD-TECH - International Foundation for the Advancement of Technology Ltd

2003-01-01

192

Understanding Rolle's Theorem  

Directory of Open Access Journals (Sweden)

Full Text Available This paper reports on an experiment studying twelfth grade students’ understanding of Rolle’s Theorem. In particular, we study the influence of different concept images that students employ when solving reasoning tasks related to Rolle’s Theorem. We argue that students’ “container schema” and “motion schema” allow for rich concept images.

REVATHY PARAMESWARAN

2009-01-01

193

NORMAL PRESSURE AND FRICTION STRESS MEASUREMENT IN ROLLING PROCESSES  

DEFF Research Database (Denmark)

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.

Henningsen, Poul; Arentoft, Mogens

2005-01-01

194

Mechano-chemical radical formation and polymerization initiation during wet grinding of alumina.  

UK PubMed Central (United Kingdom)

The formation of free radicals during wet grinding of alumina in a stirred media mill was studied by using the test radical 2,2-diphenyl-1-picrylhydracyl (DPPH). The kinetics of mechano-chemical radical formation follows a zeroth-order rate law. Particle breakage as well as mechanical activation of the surface of the alumina particles contributes to the radical formation. The rate constants of the radical formation due to mechanical activation of the particle surface k(A) and due to particle breakage k(B) depend on the milling process parameters. The radical formation during wet grinding of alumina was exploited to initiate mechano-chemical polymerization reactions of acrylic acid and acryl amide, respectively. In this way nanoparticles functionalized with polyacrylic acid and polyacryl amide, respectively, are obtained. The influence of the milling process parameters on the kinetics of mechano-chemical radical formation and on the grafted amount of polymer is discussed on the basis of stress energy and number of stress events in the mill. A correlation between the grafted amount of polyacryl amide on the alumina particles and the total radical formation rate was found showing that the concentration of mechano-chemically formed free radicals governs the efficacy of a chemical reaction at activated particle surfaces.

Damm C; Peukert W

2011-11-01

195

Mechano-chemical radical formation and polymerization initiation during wet grinding of alumina.  

Science.gov (United States)

The formation of free radicals during wet grinding of alumina in a stirred media mill was studied by using the test radical 2,2-diphenyl-1-picrylhydracyl (DPPH). The kinetics of mechano-chemical radical formation follows a zeroth-order rate law. Particle breakage as well as mechanical activation of the surface of the alumina particles contributes to the radical formation. The rate constants of the radical formation due to mechanical activation of the particle surface k(A) and due to particle breakage k(B) depend on the milling process parameters. The radical formation during wet grinding of alumina was exploited to initiate mechano-chemical polymerization reactions of acrylic acid and acryl amide, respectively. In this way nanoparticles functionalized with polyacrylic acid and polyacryl amide, respectively, are obtained. The influence of the milling process parameters on the kinetics of mechano-chemical radical formation and on the grafted amount of polymer is discussed on the basis of stress energy and number of stress events in the mill. A correlation between the grafted amount of polyacryl amide on the alumina particles and the total radical formation rate was found showing that the concentration of mechano-chemically formed free radicals governs the efficacy of a chemical reaction at activated particle surfaces. PMID:21820123

Damm, C; Peukert, W

2011-07-22

196

Effects of hot-rolling temperature and reduction ratio on edge cracking of hot-rolled boron-stainless steel  

International Nuclear Information System (INIS)

[en] The effects of hot-rolling temperature and reduction ratio on edge cracking in hot-rolled stainless steel containing 1.1% boron were investigated by using a hot-mill simulator. The main results are as follows: (1) The temperature at the side of hot-rolled steel sheets (Ts) during hot-rolling was significantly lower than at the center of hot-rolled steel sheets (Tp) just before hot rolling. (2) Ts at the start of edge cracking was not constant and increased with increasing reduction per pass. (3) The total reduction until the start of edge cracking was constant and was not dependent on Ts or the reduction per pass. (4) It is concluded that total reduction is the main factor in edge cracking due to rapid work hardening of the matrix (?phase), and owing to cavities occurring at the interface of the matrix and boride under constant strain conditions. (author)

1998-01-01

197

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

DEFF Research Database (Denmark)

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

Lagergren, Jonas; Wanheim, Tarras

2005-01-01

198

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)

1997-01-01

199

Multi-stage FE simulation of hot ring rolling  

Science.gov (United States)

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.

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

2013-05-01

200

The Heat Conditions of the Cold Pilger Rolling  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of technological factors and constructive parameters of the cold pilger rolling mill to the warm conditions of deformation is observed. The dependences of the heat conditions of pilger rolling on deformation mode and preheating temperature are shown. There was a conclusion drawn about the expediency of combination of warming and cooling of the metal for keeping the deformation zone temperature within limit, which corresponds to the minimal intensity of the metal strengthening.

Frolov, Ya. V.; Mamuzi?, I.; Danchenko, V. N.

2006-01-01

 
 
 
 
201

Off-line calculation of pass schedule for hot rolling stainless steel strip and establishment of model parameters for on-line set up calculation  

International Nuclear Information System (INIS)

In this paper, the method to calculate the roughing and finishing rolling forces is described. The way to establish the model parameters for on-line process set up calculation during developing hot rolling stainless steel strip in 2050mm hot rolling mill of Baosteel, is also introduced. Rolling test shows that the rolling forces calculated by on-line process set up model agree well with measured data. (author)

2000-01-01

202

Off-line calculation of pass schedule for hot rolling stainless steel strip and establishment of model parameters for on-line set up calculation  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the method to calculate the roughing and finishing rolling forces is described. The way to establish the model parameters for on-line process set up calculation during developing hot rolling stainless steel strip in 2050mm hot rolling mill of Baosteel, is also introduced. Rolling test shows that the rolling forces calculated by on-line process set up model agree well with measured data. (author)

Huang, C.Q.; Yuan, J.G. [Hot Strip Mill Dept., Shanghai Baosteel Group, Shanghai (China)

2000-07-01

203

Strip shape analysis in unsymmetrical rolling; Sayu hitaisho atsuen no keijo seigyo kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Model for analyzing unsymmetrical rolling based on a matrix model is built for a 6-stage rolling mill (UC mill) known for its excellent performance in correcting unsymmetrical shapes. The shape controlling properties of the UC mill in unsymmetrical rolling are examined by use of this analysis model. An experiment of unsymmetrical rolling is conducted in which the differentiated loads and the intermediate roll shift are changed, and it is found that there is good agreement between the calculated values and the values obtained from the experiment and that this analysis model works accurately in the analysis of unsymmetrical rolling. There holds a linear relationship between the unsymmetrical component involving the plate edge and quarter section inlet side plate crown and the unsymmetrical component involving the outlet side plate shape, and the effect of the inlet side plate crown can be quantified. When the work roll diameter is large, the scope of unsymmetrical shape control application is small because the controlling properties of the unsymmetrical shape controlling means are alike. When the work roll diameter is small, however, the unsymmetrical shape may be effectively controlled because the controlling properties are greatly dependent on the combination of the unsymmetrical intermediate roll shift with differentiated loads or with the unsymmetrical intermediate roll bender. 5 refs., 14 figs., 4 tabs.

Aizawa, A.; Hara, K.; Nakamoto, K. [Nippon Seiko K.K., Tokyo (Japan)

1997-09-30

204

New concept in grinding for energy efficiency  

Energy Technology Data Exchange (ETDEWEB)

The objective was to assess the potential energy savings of a laboratory-scale, conveyor-belt-type autogenous (new-concept) mill and compare its performance to a 5.5-ft diameter conventional autogenous mill. The project included provisions for the design, construction, and field testing of a pilot-scale, new-concept mill and technology transfer activities. Comparative tests with the laboratory-scale, new-concept and conventional mills, using taconite ore, revealed the new-concept mill as inefficient in terms of process and mechanical energy requirements.

Karra, V.K.

1984-01-01

205

Internal roll compression system  

Energy Technology Data Exchange (ETDEWEB)

This invention is a machine for squeezing water out of peat or other material of low tensile strength; the machine including an inner roll eccentrically positioned inside a tubular outer roll, so as to form a gradually increasing pinch area at one point therebetween, so that, as the rolls rotate, the material is placed between the rolls, and gets wrung out when passing through the pinch area.

Anderson, Graydon E. (850 Latonka Dr., R.D. 4, Mercer, PA 16137)

1985-01-01

206

New methods of measurement for obtaining information on the grinding and ignition characteristics of power plant coals; Neue Messverfahren zur Gewinnung von Informationen ueber das Mahl- und Zuendverhalten von Kraftwerkskohlen  

Energy Technology Data Exchange (ETDEWEB)

New laboratory meathods are described for investigating the grinding and ignition characteristics of power plant coal. Examples are presented to show what kind of information is provided by these methods. The test stand uses a laboratory roller mill for simulated circulation grinding. An analysis of the flame pattern provides information on the ignition characteristics of the coal and the stability of the coal dust flames. (orig./AKF)

Werner, V.; Remke, S.; Zelkowski, J.

1997-12-31

207

Mill's proof  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper I examine how Mill's argument in 'Utilitarianism' may be interpreted as a deductively valid proof of the Principle of Utility. , Citation: Mawson, T. J. (2002). 'Mill's proof', Philosophy, 77(3), 375-405. [Available at http://journals.cambridge.org/action/displayJournal?jid=PHI]...

Mawson, Tim

208

Multi-scale modelling of hot rolled dual-phase steels for process design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis investigates and models the austenite to ferrite transformation in the hot rolling of two different dual phase steels. The investigation has been carried out in a deformation dilatometer as well as a 4-stand pilot rolling mill. Three different modelling approaches were employed to give d...

Suwanpinij, Piyada

209

Carving up Word Meaning: Portioning and Grinding  

Science.gov (United States)

|Two eye-tracking experiments investigated the processing of mass nouns used as count nouns and count nouns used as mass nouns. Following Copestake and Briscoe (1995), the basic or underived sense of a word was treated as the input to a derivational rule (''grinding'' or ''portioning'') which produced the derived sense as output. It was…

Frisson, S.; Frazier, L.

2005-01-01

210

Food grinding and chopping devuce & method  

UK PubMed Central (United Kingdom)

A mortar and pestle and a chopping bowl are provided with bottom walls which can engage one another when one is placed atop of the other when the bottom unit is upside-down. The combined units provide a stable surface to either grind or chop food articles on, and provide for compact storage of the items when not in use.

KAVANAUGH SUSAN R; ROBBINS RODNEY W

211

Production of powder Ti-alloy rings by means of compaction and radial-rolling  

Energy Technology Data Exchange (ETDEWEB)

Combined-die-compaction (MVV) and rolling is used to produce rings from Ti-6Al-4V powder. The influence of deformation and of heat treatment on the microstructure of Ti-alloy rings was investigated. Plastic deformation of phi/sub v/=0,615 when rolling in a ring rolling mill at 900/sup 0/C and annealing at 925/sup 0/C for 0,5 h results in the required homogenous globular microstructure.

Szczepanik, S.; Kopp, R.; Wiegels, H.

1988-12-01

212

Magnetocaloric properties of amorphous GdNiAl obtained by mechanical grinding  

International Nuclear Information System (INIS)

[en] An amorphous GdNiAl sample was prepared by mechanical grinding performed on a crystallised intermetallic. The treatment changes greatly the ferromagnetic behaviour of this compound; its Curie temperature decreases from 57 K (unmilled sample) to 29 K (milled sample). Specific heat and magnetisation measurements reveal that amorphous GdNiAl exhibits an interesting magnetocaloric effect; for an applied magnetic field of 5 T a change of ?8.9 J/kg K is observed at 36 K for the isothermal magnetic entropy. (orig.)

2005-01-01

213

Rolling friction and bistability of rolling motion  

CERN Multimedia

The rolling motion of a rigid cylinder on an inclined flat viscous surface is investigated and the nonlinear resistance force against rolling, $F_R(v)$, is derived. For small velocities $F_R(v)$ increases with velocity due to increasing deformation rate of the surface material. For larger velocity it decreases with velocity due to decreasing contact area between the rolling cylinder and the deformed surface. The cylinder is, moreover, subjected to a viscous drag force and stochastic fluctuations due to a surrounding medium (air). For this system, in a wide range of parameters we observe bistability of the rolling motion. Depending on the material parameters, increasing the noise level may lead to increasing or decreasing average velocity.

Pöschel, T; Brilliantov, N; Zaikin, A; Poeschel, Thorsten; Schwager, Thomas; Brilliantov, Nikolai; Zaikin, Alexei

2005-01-01

214

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

UK PubMed Central (United Kingdom)

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.

Juhnke M; Märtin D; John E

2012-05-01

215

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

Science.gov (United States)

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

Juhnke, Michael; Märtin, Dirk; John, Edgar

2012-01-17

216

The Effect of Cutting Speed in Metallic Glass Grinding  

Science.gov (United States)

In this paper, the effects of the cutting speed in metallic glass grinding were investigated in dry conditions. The results showed that grinding forces decrease as grinding energy increase with the increasing cutting speeds. The present investigations on ground surface and grinding chips morphologies -shows that material removal and surface formation of the BMG are mainly due to the ductile chip deformation and ploughing as well as brittle fracture of some particles from the edges of the tracks. The roughness values obtained with the Cubic Boron Nitride wheels are acceptable for the grinding operation.

Serbest, Erdinc; Bakkal, Mustafa; Karipcin, Ilker; Derin, Bora

2011-01-01

217

High-speed milling of light metals  

Directory of Open Access Journals (Sweden)

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.

F. Cus; U. Zuperl; V. Gecevska

2007-01-01

218

Dressing of fine grained diamond grinding wheels for ultra precision grinding of structured molds in brittle hard materials  

Science.gov (United States)

The manufacturing of structured molds calls for alternatives in terms of grinding wheel geometry and dressing. To manufacture geometric features in the micron range on molds, sharp edged fine grained grinding wheels can be used. A dressing procedure with metal alloy blocks is used to create sharp edged grinding wheels. This paper presents results and achieved tip radii of dressed resin bonded and metal bonded grinding wheels. Furthermore, a grinding test on a tungsten carbide mold is carried out to create a diffractive structure and the achieved form accuracy and surface roughness are presented.

Bletek, Thomas; Klocke, Fritz; Hünten, Martin; Dambon, Olaf

2013-09-01

219

Flotation of oil-agglomerated coal for ash and pyrite removal -- Simultaneous grinding and agglomeration  

Energy Technology Data Exchange (ETDEWEB)

Oil agglomeration is an excellent technique for the beneficiation of fine coal. For separation of the spherical agglomerates by screening, a high level of oil must be used, however. When the subsequent separation is done by flotation, this disadvantage is eliminated. Better pyrite removal is also possible. In this paper, such a fine coal beneficiation process, also called hydrophobic flocculation-flotation (HFF), is described. It features low non-polar oil consumption, intensive mechanical energy input, and smaller agglomerates or looser flocs. This process can be simplified by grinding the coal in water with small amounts of oil added. The excess grinding energy is then used for agglomerating the coal. The Prince coal from Nova Scotia contained 13.3% ash and 3.3% total sulfur, 1.4% pyritic. After four stages of flotation, ash and pyrite removal were 93% and 66% respectively, with 87% combustibles recovery. The parameters affecting the HFF process, such as particle size, dosage of non-polar oil, pH value of the slurry and duration of agitation, were investigated. Simultaneous grinding and agglomeration (SGA) utilizing the Szego Mill was also explored at the very low oil levels used. The intensive agitation/preconditioning step prior to flotation was eliminated. When the other parameters established from the sequential process were used with the SGA process, virtually identical beneficiation results were obtained, but with slightly lower combustibles recovery. While further testing is required to properly optimize the SGA process conditions, significant equipment simplification and energy savings are possible.

Song, S.; Perkson, A.; Trass, O. [Univ. of Toronto, Ontario (Canada). Dept. of Chemical Engineering and Applied Chemistry

1996-12-31

220

Evaluation on some important force models for cold strip rolling  

Energy Technology Data Exchange (ETDEWEB)

To improve the accuracy of rolling force prediction, some important force models were evaluated through applied computation for cold rolling of low carbon steel and aluminum alloy according to measured data on lab mill. The effects of model structure and three important variables - flow stress, contact length and friction coefficient - on the precision of computed force were quantitatively studied. Flow stress was measured with plane-strain compression test, contact length was based on elastic flattening of work-roll by Hitchcock, and friction-coefficient was determined by rolling strain and numerical iteration. In steel rolling Bland and Ford integration model and Bryant and Osborn algebraic equation are better in accuracy than Ekelund and Parkins. In aluminum rolling all the models produce large deviations {delta}F{sub R} = 10-20% if flow stress, contact length and friction coefficient are determined with the same method as steel rolling. The elastic deformation of aluminum strip is now taken into account for its low elastic modulus. An effective method to determine plastic and elastic contact has been developed in this investigation. The accuracy of force computation is obviously improved for aluminum rolling. (orig.)

Li Guangying; Lagergren, J. [Royal Inst. of Tech. (KTH), Stockholm (Sweden). Dept. of Material Processing

2000-11-01

 
 
 
 
221

Development of grinding models for brittle materials  

Energy Technology Data Exchange (ETDEWEB)

The fracture mechanics used to predict subsurface damage during machining requires knowledge of the depth of cut of the tool. For brittle materials, analysis shows that there will be ductile response for cutting depths below a critical value and brittle response for depths above this value. Finding the depth of cut is relatively straightforward for single-point machining such as diamond turning, but much more difficult for the large number of randomly arranged grains involved in grinding. The aim of this research is to develop models for the statistical effects of multiple cutting grains. The key issue for the models is to derive the grain depth-of-cut for a distribution of cutting grains and specified operating conditions. In order to simplify the development work, plunge grinding (no cross feed) is being used for the prototype geometry.

Sharp, K.; Scattergood, R.O. [North Carolina State Univ., Raleigh, NC (United States)

1996-12-31

222

Loesche vertical roller mills for the comminution of ores and minerals  

Energy Technology Data Exchange (ETDEWEB)

LOESCHE vertical roller mills are widely used for the comminution of raw materials in the cement industry, for the comminution of clinker and blast furnace slag and for the production of pulverized coal for cement kilns, blast furnaces and power plants. Recent research has shown, that the application of these vertical roller mills in dry grinding of ores and minerals can lead to significantly better recovery rates and higher grades when compared to conventional grinding. Since mid 2000 a LM 50.4 has been in operation for the comminution of a phosphate carrying pyroxenite ore.

Schaefer, H.U. [LOESCHE GmbH, Dusseldorf (Germany)

2001-10-01

223

Load-signature analysis for pack rolling of near-gamma titanium aluminide alloys  

Energy Technology Data Exchange (ETDEWEB)

The objective of the present work was to demonstrate the sensitivity of rolling-load signature analysis as a means to monitor hot-pack-rolling processes for the fabrication of sheet of near-gamma titanium-aluminide alloy sand other difficult-to-work materials. In previous work, a simple method was developed for the prediction of temperature transients during two steps in the pack-rolling process: the transfer of the pack from the furnace to the rolling mill and the actual rolling operation itself. The accuracy of the temperature-transient calculations was established through load-signature data obtained during trials for Ti-48Al (atomic percent) rolled at a single nominal (furnace) temperature. In the present work, additional results are presented and discussed for hot pack rolling at various nominal temperatures and for a range of near-gamma titanium-aluminide alloys.

Semiatin, S.L. (Wright Lab. Materials Directorate, Wright-Patterson AFB, OH (United States). Metals and Ceramics Division); Seetharaman, V. (UES, Inc., Dayton, OH (United States))

1994-11-01

224

Feeding roll presses for stable roll operation  

Energy Technology Data Exchange (ETDEWEB)

Roll presses are used to agglomerate bulk solids ranging from extremely fine magnesium oxide, salt, potash, and coal, to very coarse metal turnings. It is easy to see that a given press will work differently with a fine powder such as magnesium oxide, than with coarse metal turnings. It is less obvious that subtle changes in size-consist of the same material may also significantly modify the effectiveness of the press. Such changes must be compensated for if the press is to consistently produce good agglomerates. This paper discusses the various material properties affecting press operation, and suggests methods of operating a roll press system for correcting for these changes.

Johanson, J.R.

1984-06-01

225

Understanding Rolle's Theorem  

Science.gov (United States)

This paper reports on an experiment studying twelfth grade students' understanding of Rolle's Theorem. In particular, we study the influence of different concept images that students employ when solving reasoning tasks related to Rolle's Theorem. We argue that students' "container schema" and "motion schema" allow for rich concept images.…

Parameswaran, Revathy

2009-01-01

226

Evaluation of roll compaction as a preparation method for hydroxypropyl cellulose-based matrix tablets.  

UK PubMed Central (United Kingdom)

Roll compaction was applied for the preparation of hydroxypropyl cellulose (HPC)-based sustained-release matrix tablets. Matrix tablets made via roll compaction exhibited higher dosage uniformity and faster drug release than direct-compacted tablets. HPC viscosity grade, roll pressure, and milling speed affected tablet properties significantly. Roll compaction seems to be an adequate granulation method for the preparation of HPC-based matrix tablets due to the simplicity of the process, less handling difficulty from HPC tackiness as well as easier particle size targeting. Selecting the optimum ratio of plastic excipients and the particle size of starting materials can however be critical issues in this method.

Jeon I; Gilli T; Betz G

2011-04-01

227

Remote-controlled grinding robot system for repair work  

International Nuclear Information System (INIS)

[en] A new teleoperated grinding robot has been developed which can safely and efficiently carry out grinding tasks in hostile environments using remote control and automatic control. This robot system incorporates a new method for the measurement of grinding force, in which the grinding force is measured from a moment about the grinder head's center of gravity. The influence of inertial forces caused by translational motion is removed, so that high stability is achieved. Furthermore, this robot can change the grinder's orientation to follow the surface of an object automatically, and can also grind the surface of an object into a desired shape. The new robot is expected to be applied to various types of grinding work in hostile environments. (author)

1991-01-01

228

Further study on coal mill modelling for on-line implementation  

Energy Technology Data Exchange (ETDEWEB)

A mathematical model of a vertical spindle coal mill to represent a complete mill process has been developed in the authors' previous work. The paper is to investigate if there is an alternative parameter identification method suitable for on-line implementation. Particle Swarm Optimisation method has been studied and applied to coal mill model parameter identification. The coal mill model can represent the coal mill normal grinding process, which consists of 9 equations and 16 unknown coefficients in total to be identified. Employing the Particle Swarm Optimization method, the 16 coefficients are identified. The paper describes the detail coal mill model process, and simulation study has been conducted. The simulation results are presented. Although the work is still in its early stage, it has shown a potential to a fast algorithm for on-line updating mill coefficients. 20 refs., 6 figs., 1 tab.

J.L. Wei; P. Zachariades; J. Wang [University of Birmingham, Birmingham (United Kingdom). Department of Electronic, Electrical and Computer Engineering

2007-07-01

229

Fabrication experience and evaluation of high energy ball mill for glove boxes  

International Nuclear Information System (INIS)

[en] A compact high energy ball mill was developed for quick and efficient milling of ceramic oxide powders inside glove boxes. This paper presents the salient features of this equipment developed and indigenously procured. Manual handling of jars and radioactive powders could be considerably reduced by use of this equipment compared with conventional jar milled at present deployed for this purpose. Large quantities of ThO2 powder have been milled in this equipment and sintered to high densities. A study of the efficiency of the machine in milling of powders has been conducted. The powder characteristics such as particle size, distribution and surface area of the powders milled in this equipment are also presented in this paper. The variation in these characteristics with time, speed and ratio of charge to grinding media has been studied and compared with those of conventional ball mill. (author)

2000-01-01

230

Roll force prediction of high strength steel using foil rolling theory in cold skin pass rolling  

International Nuclear Information System (INIS)

Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high strength steel below TS 980 MPa in skin pass rolling

2013-01-01

231

Kinetics of wet grinding of submicrone tungsten carbide powders  

International Nuclear Information System (INIS)

[en] The influence of temperature of ultradisperse tungsten carbidizing treatment on dispersion, fine structure and character of carbide frinding in the process of mixture preparation with 8%Co was studied. Considerable difference in grinding kinetics for submicron doped and standard tungsten carbide during wet grinding was ascertained. It is expressed in a less intensive growth of characteristics of dispersion and X-ray band width of submicron powder. It proved possible to reduce grinding time of mixtures on the basis of such powders. A change in grinding ability of finely dispersed tungsten carbide with an increase in the temperature of its production up to 1600-1700 deg C was detected

1992-01-01

232

Technical aspects of the linkage of the processing steps of the cold rolling steel plants; Aspectos tecnicos ligados ao acoplamento de linhas de processo na laminacao de tiras a frio  

Energy Technology Data Exchange (ETDEWEB)

Several industries have made efforts to attain an actual link between processing lines. In special, at cold rolling steel plants. This link have been made involving continuous pickling lines, cold tandem mill, annealing lines and temper mill. Design aspects and data simulation of this new tendency in cold rolling processing lines are discussed in this paper. 2 figs., 4 tabs., 6 refs.

Oliveira, Generoso N.; Massuda, Marcelo S. [COBRAPI, Belo Horizonte, MG (Brazil)

1990-12-31

233

Learning Activity Packets for Grinding Machines. Unit II--Surface Grinding.  

Science.gov (United States)

|This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the second unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

234

Learning Activity Packets for Grinding Machines. Unit III--Cylindrical Grinding.  

Science.gov (United States)

|This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the third unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

235

Learning Activity Packets for Grinding Machines. Unit I--Grinding Machines.  

Science.gov (United States)

|This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the first unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

236

The chemistry of 226Ra in the uranium milling process  

International Nuclear Information System (INIS)

Uranium mining, ore crushing, grinding and leaching can substantially redistribute radium in the environment. Solvent extraction or other separation processes leave mill tailings with high 226Ra concentration. Radium is readily adsorbed on the surfaces of leached solids or coprecipitated with barium sulfates. More solid ore phase studies are required to identify all the physico-chemical mechanisms controlling 226Ra dissolution from leaching ore-liquor systems. 29 refs, 5 figs, 4 tabs

1990-01-01

237

Combustion performance characteristics of fine grind fuels  

Energy Technology Data Exchange (ETDEWEB)

The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of Beneficiated Coal-Based Fuels (BCFs) influencing combustion, ash deposition, ash erosion, particulate collection, and emissions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs. To date, twelve beneficiated coal-based fuels have been acquired through PETC and tested at ABB Power Plant Laboratories Fireside Performance Test Facility (FPTF). The results from these fuels indicate that firing the BCFs improved furnace heat transfer and fly ash erosion compared to their respective feed coals. This paper presents the results from a series of combustion test runs recently conducted in the FPTF to address the effect of fuel fineness on performance. A conventionally cleaned at the mine Pittsburgh No. 8 (Emerald mine, Green County, Pennsylvania, Cyprus Coal Company) was acquired and prepared at three grinds (standard, fine and ultra-fine grinds) to evaluate the effect of fuel fineness on combustion performance. The three fuels were tested at firing rates ranging from 3.0 {times} 10{sup 6} Btu/h to 4.0 {times} 10{sup 6} Btu/h, at standard (no staging) and two staged firing conditions.

Chow, O.K.; Levasseur, A.A.

1996-12-31

238

Milling effect preparing Ti-graphite based hydrogen storage material  

Energy Technology Data Exchange (ETDEWEB)

Recently there are several researches proposed that hydrogen storage material prepared by mechanical grinding of magnesium (Mg) and graphite could enhance the hydrogen storage ability. Where the additives of graphite presents as catalyst of alloy due to the cleavage-degraded graphite in the composites. The Ti-base alloy and expandable graphite was used in this work to produce a high hydrogen storage composite material in room temperature with pressure less than 50 atm. The mill condition and graphite addition amount played the important role in composite prescription. The milling condition such as shear type milling or shock type milling which might affect the state of composite material is also discussed in this work. (author)

Yen, P.S.; Hsiao, C.S.; Cheng, K.W.; Kuo, J.C. [Industrial Technology Research Inst., Advanced Energy Technology Lab., Energy and Resources Laboratories, Hsinchu, Taiwan (China)

2004-07-01

239

30 CFR 57.15014 - Eye protection when operating grinding wheels.  

Science.gov (United States)

...false Eye protection when operating grinding wheels. 57.15014 Section 57...15014 Eye protection when operating grinding wheels. Face shields or goggles in...condition shall be worn when operating a grinding wheel. [53 FR 32533, Aug....

2010-07-01

240

30 CFR 56.15014 - Eye protection when operating grinding wheels.  

Science.gov (United States)

...false Eye protection when operating grinding wheels. 56.15014 Section 56...15014 Eye protection when operating grinding wheels. Face shields or goggles in...condition shall be worn when operating a grinding wheel. [53 FR 32526, Aug....

2010-07-01

 
 
 
 
241

Investigation of fine grinding and flotation to produce superclean coal. [Dry-ground and wet-ground  

Energy Technology Data Exchange (ETDEWEB)

Laboratory flotation tests were conducted with dry-ground and wet-ground coal to determine the effect of grinding methods on clean coal recovery and product grade. A laboratory jar mill, a stirred ball mill, and an air-classifying vertical impact mill were used for grinding the coal samples. Products of as near the same size distribution as possible were prepared by each method (i.e., nominal minus 27 ..mu..m with a mean particle size of 10 to 12 ..mu..m). The test results show that dry-ground coal is more floatable at lower reagent addition levels, but wet-ground coal provides lower ash products. For example, a dry-ground coal yielded about 40 wt % to over 70 wt % of froth product with frother reagent dosages of 0.2 to 0.5 pound per ton of dry solids (lb/ton), and the respective product ash contents ranged from about 2.0% to 3.0%. A wet-ground coal, on the other hand, yielded under 30 wt % to a little over 70 wt % froth product with the same frother reagent dosages, but the ash contents ranged from about 1.0% to 1.6%. 5 refs., 5 figs., 2 tabs.

Miller, K.J.

1985-05-01

242

Rolling shutter device condom  

UK PubMed Central (United Kingdom)

The utility model relates to a rolling machine safety cover, belonging to the safety device on the role of the rolling machine shaft. The utility model provides a rolling machine safety cover which prevents the role of the rolling machine from hurting. The utility model comprises an upper semi circular cover and a lower semi circular cover wherein the upper semi circular cover has two connecting boards respectively positioned at the two sides and the lower semi circular cover has two connecting boards respectively positioned at the two sides as well. The structure points of the utility model lie in that: the upper semi circular cover and the lower semi circular cover respectively have a semi circular shell which has the corresponding axis diameter as the rolling machine, a semi circular shell which has the corresponding outer role diameter as the two shaft of the rolling machine two role through holes are arranged on the shaft of the semi circular shell which has the corresponding outer diameter of the upper semi circular cover the through holes are arranged on the routing direction of the role and are provided with an extendable pipe which consists of a thick pipe and a thin pipe wherein the thick pipe has the same inner diameter as the outer diameter of the through hole and the thin pipe has the same inner diameter as the through hole moreover, the extendable pipe can be arranged on the through hole.

GUOJI WANG

243

Design factors for milling sweet sorghum  

Energy Technology Data Exchange (ETDEWEB)

A conveyor/shredder/3-roll mill system was modified to process 30-cm billets of sweet sorghum and to develop basic design information. Percent juice extracted increased with throughput until the system plugged. Maximum operable rates for whole plants and stalks were respectively 19 and 25 kg/min, and about 48 percent of total crop sugar was recovered from either plants or stalks.

Monroe, G.E.; Bryan, W.L.

1983-06-01

244

Oil separation from foam fractions of enzymatically treated wet milled corn germ dispersions  

Science.gov (United States)

The many recent dry grind plants that convert corn to ethanol are potential sources of substantial amounts of corn oil, if an economical method of separating it can be developed. Oil was separated from corn germ by aqueous enzymatic extraction (AEE). Batches of wet- milled corn germ in water were...

245

Stochastic dynamic programming applied to planning of robot grinding tasks  

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-10-01

246

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

DEFF Research Database (Denmark)

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.

Lagergren, J.; Wanheim, Tarras

2006-01-01

247

Spray Rolling Aluminum Strip  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2006-05-10

248

Modified oil agglomeration process for coal beneficiation; IV pilot-plant demonstration for the simultaneous grinding-agglomeration process  

Energy Technology Data Exchange (ETDEWEB)

The Simultaneous Grinding Agglomeration (SGA) process with the Szego Mill is examined and compared to other methods of coal beneficiation. The SGA process has been tested over a wide range of operating conditions and demonstrated in the laboratory and in a 12 tonnes/day pilot plant. The test results are comparable. No problems are foreseen on scale up to a demonstration unit. The economics of the SGA process for slurry fuel preparation is evaluated, and the final cost of beneficiated coal slurry fuel is found to be competitive with oil. 12 refs., 3 figs., 4 tabs.

Trass, O.; Vasquez, E.R.; Campbell, P.D.; Gandolfi, E.A.J.; Koka, V.R. (University of Toronto, Toronto, ON (Canada). Chemical Engineering and Applied Chemistry)

1994-02-01

249

IMPROVING ENERGY EFFICIENCY VIA OPTIMIZED CHARGE MOTION AND SLURRY FLOW IN PLANT SCALE SAG MILLS  

Energy Technology Data Exchange (ETDEWEB)

The U.S. mining industry operates approximately 80 semi-autogenesis grinding mills (SAG) throughout the United States. Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between 2.0 and 7.5 kWh per ton of energy to reduce the particle size. Considering a typical mining operation processes 10,000 to 100,000 tons per day the energy expenditure in grinding is 50 percent of the cost of production of the metal. 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, Kennecott Utah Copper Corporation, Process Engineering Resources Inc. and others. In the current project, Cortez Gold Mines played a key role in facilitating the 26-ft SAG mill at Cortez as a test mill for this study. According to plant personnel, there were a number of unscheduled shut downs to repair broken liners and the mill throughput fluctuated depending on ore type. The University team had two softwares, Millsoft and FlowMod to tackle the problem. Millsoft is capable of simulating the motion of charge in the mill. FlowMod calculates the slurry flow through the grate and pulp lifters. Based on this data the two models were fine-tuned to fit the Cortez SAG will. In the summer of 2004 a new design of shell lifters were presented to Cortez and in September 2004 these lifters were installed in the SAG mill. By December 2004 Cortez Mines realized that the SAG mill is drawing approximately 236-kW less power than before while maintaining the same level of production. In the first month there was extreme cycling and operators had to learn more. Now the power consumption is 0.3-1.3 kWh/ton lower than before. The actual SAG mill power draw is 230-370 kW lower. Mill runs 1 rpm lesser in speed on the average. The re-circulation to the cone crusher is reduced by 1-10%, which means more efficient grinding of critical size material is taking place in the mill. All of the savings have resulted in reduction of operating cost be about $0.023-$0.048/ ton.

Raj K. Rajamani; Sanjeeva Latchireddi; Sravan K. Prathy; Trilokyanath Patra

2005-12-01

250

Air/oil lubrication of mill drives  

Energy Technology Data Exchange (ETDEWEB)

Large gear drives and power shaft bearings for rolling mills have historically been lubricated with circulating oil, wet sump systems that flood gears and bearings with large volumes of oil. Recent investigations have demonstrated that such systems contribute to heat build-up from oil-shear friction and increase drive power consumption. Other problems include: compromises in the selection of a single oil to serve different types of lubrication points; high oil consumption; contamination of lubricating oil by process fluids; contamination of process fluids and mill product by lubricating oil; and health, safety and environmental issues. To improve the performance of the 6-stand continuous billet/round rolling mill in its Lorain, Ohio facility, USS/KOBE Steel developed a hybrid air/oil centralized system to replace a circulating oil system pumping 150 gpm with a system delivering only 42 cu in./hr to each stand. This article discusses the continuous improvement process which identified the hybrid air/oil system, and the test and development steps that proved its suitability. In addition, the basic theory, equipment and controls that have made the series-progressive air/oil concept a practical and beneficial technique for heavy-duty mill drives are presented.

Nemes, G.L. [Lubriquip, Cleveland, OH (United States); Balogh, D. [F.D. Johnson Co., Cleveland, OH (United States); Wilson, G.A. [USS/KOBE Steel Co., Lorain, OH (United States)

1995-07-01

251

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.

2013-01-01

252

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

Energy Technology Data Exchange (ETDEWEB)

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.

Yamanaka, Shinya, E-mail: syama@mmm.muroran-it.ac.jp [Muroran Institute of Technology, College of Environmental Technology (Japan); Suzuma, Akifumi [Muroran Institute of Technology, Division of Applied Sciences (Japan); Fujimoto, Toshiyuki; Kuga, Yoshikazu [Muroran Institute of Technology, College of Environmental Technology (Japan)

2013-04-15

253

Ship Roll Damping Control  

DEFF Research Database (Denmark)

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 diculties 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 dierent 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.

Perez, Tristan; Blanke, Mogens

2012-01-01

254

Automatic food rolling machine  

UK PubMed Central (United Kingdom)

The invention discloses an automatic food rolling machine, comprising a box body (1), and further comprising a base plate (2) that is flat and fixedly mounted on the bottom surface inside the box body (1) at least two moving members mounted in the box body (1), arranged above the base plate (2) oppositely, connected with a power member (4) and controlled by the power member (4) to move above the base plate (2) and a control device (5) electrically connected to the power member (4) and controlling the movement parameters of the power member (4). The automatic food rolling machine has simple structure and stable performance, is used and maintained conveniently, and can adequately ensure safety and sanitation of foods such as sushi and rice and vegetable roll in the manufacturing process, and ensure the manufactured finished products to have stable taste. Thus, the invention can well satisfy the household use of people.

ZAOYAN LIU

255

Heat treatment in hot strip rolling of steel  

Energy Technology Data Exchange (ETDEWEB)

Heat treatment aims at optimal properties by control of metallurgical mechanisms during a controlled temperature-time cycle. This can be combined with deformation during this cycle. During hot rolling of steel in a hot strip mill all the metallurgical aspects play an important role, often in such a way that they even influence the control of the process of rolling and cooling itself. The installation is designed for bulk production. Due to market development however the specifications of the final product change very frequently. This makes control of process and material properties very difficult. To obtain a good process control all the metallurgical processes have to be known and quantified during the specific rolling cycle, including the interactions with the process. To solve this problem we have chosen at Hoogovens an approach with physical mathematical models, where the metallurgical models are integrated with the process models. In such a way a practical and economical solution can be found for the production of high quality coils. This approach will be dealt with and illustrated with results from rolling experiments in the Hot Strip Mill. (orig.)

Hoogendoorn, T.M. (HOOGOVENS GROEP BV, Applied Physical Metallurgy Dept. (Netherlands)); Hoogen, A.J. van den (HOOGOVENS GROEP BV, Applied Physical Metallurgy Dept. (Netherlands))

1994-01-01

256

METHOD OF ROLLING URANIUM  

Science.gov (United States)

A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

Smith, C.S.

1959-08-01

257

Ship Roll Motion Control  

DEFF Research Database (Denmark)

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.

Perez, Tristan School of Engineering,, The University of Newcastle

2010-01-01

258

Cocrystallization via planetary milling: enhancing throughput of solid-state screening methods.  

Science.gov (United States)

The application of a novel modified planetary mill, with the capacity to process 48 samples in parallel, to the rapid screening of pharmaceutical cocrystals via grinding is demonstrated for carbamazepine/saccharin, caffeine/oxalic acid, and caffeine/maleic acid cocrystals. Milling is performed directly in standard glass vials therefore no vessel decontamination is needed or sample loss occurs. Furthermore, successive sample processing can be employed without the need for additional material, making the system suitable for screening compounds of limited availability. Use of the system in an automated screening workflow of dispensing, milling, and analysis with high-throughput is also discussed. PMID:21439363

Bysouth, Stephen R; Bis, Joanna A; Igo, David

2011-03-23

259

Tests of ball drum mills in conditions of rated and maximum loads  

Energy Technology Data Exchange (ETDEWEB)

The productivity of ball mills is determined, at given operating conditions, by the properties of the fuel being pulverized. The basic fuel properties that affect ball mill productivity are the ash content and moisture. A system of load control and protection from emergency overloading allows the operation of the mill to be improved during grinding of solid fuel of poor or changeable quality. Measures for raising the drying capability and streamlining the coal return system makes possible a 25-30% increase in pulverization system productivity.

Golyshev, L.V.; Sinyakevich, B.G.; Krasnoshtan, N.N.; Barkov, G.P.

1982-12-01

260

Methodology for automatic selection of passes in surface grinding  

Directory of Open Access Journals (Sweden)

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 for 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.

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

2007-01-01

 
 
 
 
261

Numerical analysis of small recessed silicon carbide grinding wheels  

Directory of Open Access Journals (Sweden)

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.

M.J. Jackson

2010-01-01

262

Preliminary study of sintering of metallic niobium processed for mechanical milling  

International Nuclear Information System (INIS)

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)

2010-01-01

263

Investigation into the causes of cracking of 2024 aluminium alloy during rolling operation  

International Nuclear Information System (INIS)

[en] Aluminium alloy 2024 bars cracked during cold rolling to produce strips conforming to T-3 temper designation. The specimens had reduced to 10 mm X 10 mm size by hot rolling rectangular ingots of size 25 mm X 25 mm in 3 passes using the rolling mill. Microscopic studies of the cracked specimens revealed the presence of inclusions on the grain boundaries and in the fracture valleys. Energy dispersive X-ray analysis (EDAX) indicated that inclusions were rich in iron. Fractrogapy of fracture specimens were carried out using both optical scanning electron microscopy which indicated brittle fracture due to the presence of iron inclusions. (author)

1993-01-01

264

Inflation Without Slow Roll.  

Science.gov (United States)

We draw attention to the possibility that inflation (i.e. accelerated expansion) might continue after the end of slow roll, during a period of fast oscillations of the inflation field Mu. This phenomenon takes place when a mild non-convexity inequality is...

T. Damour V. F. Mukhanov

1997-01-01

265

Rotary tillage rolling apparatus  

UK PubMed Central (United Kingdom)

The utility model relates to a rotary tillage calamus rolling device comprising rotary tillage knives and a central round tube. The rotary tillage knives are in the shape of arch knife blades and are fixed at the tangent position of the round tube. The longitudinal distances of each row of rotary tillage knife blades are equal, every two adjacent knife blades in the circumference of the round tube are rotated by from 10 DEG to 20 DEG, 3 to 5 rows of rotary tillage knives distributed in spiral lines are fixed on the round tube, a flat iron bar is welded on each row of rotary tillage knives, and the iron bar is fixed in a sloping line at the middle of each rotary tillage knife in the row. The rotary tillage calamus rolling device is characterized in that four running blades in the shape of a crisscross are fixed at one end of the round tube, which is farther from a running wheel, the height of the running blades equals to the radius of the rotary tillage calamus rolling device, the cross section of the running blades is of a sink shape, and openings of the four blades face the direction towards which a tillage calamus ship moves. When the rotary tillage calamus rolling device works, the running blades at the end part are inserted in mud, play the role of assisting a running drive, and enable the tillage calamus ship to have more balanced running.

SHENGHAO HE

266

Preparation of micro carbide spheres by gas grinding  

International Nuclear Information System (INIS)

[en] Micro B4C spheres with an average sphere factor of 0.95 has been prepared by gas grinding method. And the theoretical relationships between the product shape factor and gas velocity has been derived

2004-01-01

267

[Spectra on the influence of grinding to kaolinite structure].  

Science.gov (United States)

Kaolinite clay is one of important ceramic materials. In this paper, the kaolinite clay was ground by dry grinding and wet grinding. The powder samples ground for different time were measured by FTIR spectra and XRD, and the changing rules of the IR absorption frequency and XRD were respectively discussed. The results indicated that wet grinding was superior to dry one. Kaolinite structure began to change while it was ground by dry mothed for 12 h, and the layer structure was destroyed completely till 42 h. However, the day structure didn't change much until 54 h at the condition of wet grinding. The mechanism of the kaolinite structure changed were also discussed in detail. PMID:12958938

Hao, Q; Yang, X; Wang, Y; Lu, L; Wang, X

2000-06-01

268

Effects of wet ball milling on lead stabilization and particle size variation in municipal solid waste incinerator fly ash  

International Nuclear Information System (INIS)

Water-extracted municipal solid waste incinerator (MSWI) fly ash was treated by a process of wet ball milling, using desalinated water as the milling solution. We investigated the influence of the milling process on the partitioning and leaching characteristics of lead (Pb) and the particle size distribution. The results show that 93.11% of the Pb was partitioned into the milled ash, 2.60% to the milling balls, and 0.17% to the inner surface of the milling jar, while amounts lower than the detection limit remained in the milled solution. As tested by the toxicity characteristic leaching procedure (TCLP), the leaching of Pb was inhibited after short-term grinding (from 5.2 to 1.2 mg/L after 1 h of milling), and further reduced by about 96% after 96 h of ball milling. The mobility of the heavy metal was analyzed after a sequential extraction procedure. The results also show that Pb tended to become more stable after milling. The size distribution of particles was analyzed by a laser particle diameter analyzer and their morphology during grinding was observed using scanning electron microscopy. The median size of the fly ash decreased significantly from 36 to 5 ?m after 0.5 h of milling, but then only slightly, from 5 to 2 ?m, with further milling from 0.5 to 96 h, due to the concurrent actions of fragmentation and/or agglomeration. The reason for the stabilization of Pb by ball milling was probably that Pb was sealed in the milled fly ash during the fragmentation and agglomeration of particles.

2010-02-15

269

Effects of wet ball milling on lead stabilization and particle size variation in municipal solid waste incinerator fly ash.  

Science.gov (United States)

Water-extracted municipal solid waste incinerator (MSWI) fly ash was treated by a process of wet ball milling, using desalinated water as the milling solution. We investigated the influence of the milling process on the partitioning and leaching characteristics of lead (Pb) and the particle size distribution. The results show that 93.11% of the Pb was partitioned into the milled ash, 2.60% to the milling balls, and 0.17% to the inner surface of the milling jar, while amounts lower than the detection limit remained in the milled solution. As tested by the toxicity characteristic leaching procedure (TCLP), the leaching of Pb was inhibited after short-term grinding (from 5.2 to 1.2mg/L after 1h of milling), and further reduced by about 96% after 96h of ball milling. The mobility of the heavy metal was analyzed after a sequential extraction procedure. The results also show that Pb tended to become more stable after milling. The size distribution of particles was analyzed by a laser particle diameter analyzer and their morphology during grinding was observed using scanning electron microscopy. The median size of the fly ash decreased significantly from 36 to 5 microm after 0.5h of milling, but then only slightly, from 5 to 2 microm, with further milling from 0.5 to 96 h, due to the concurrent actions of fragmentation and/or agglomeration. The reason for the stabilization of Pb by ball milling was probably that Pb was sealed in the milled fly ash during the fragmentation and agglomeration of particles. PMID:19828240

Li, Ming-Guo; Sun, Chang-Jung; Gau, Sue-Huai; Chuang, Chia-Jung

2009-09-23

270

Hot strip mill as an experimental tool (review)  

Energy Technology Data Exchange (ETDEWEB)

The occurrence of carbonitride precipitation during the short interpass times associated with hot strip rolling is considered, together with the interaction between precipitation and static recrystallization under these conditions. The characteristics of work hardening and of strain accumulation at the high temperatures (850 to 1,050 degree C) involved in strip rolling are described. Expressions are introduced that specify the kinetics of softening (by static or metadynamic recrystallization) during the interpass interval in various grades of steel. Using these kinetics in an appropriate mill model, the mean flow stresses pertaining to various mill stands are predicted. These values are compared with the measured ones derived directly from mill logs. It is shown how discrepancies between the predicted and measured values can be used to improve the accuracy of the expressions for the kinetics. This is one way in which a hot strip mitt can be used as an 'experimental tool'. (author)

Jonas, J.J.

2000-08-01

271

A critical study of high efficiency deep grinding  

International Nuclear Information System (INIS)

[en] 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, Barkhausen Noise Amplitude (BNA) measurements, surface roughness and Vickers micro-hardness appraisal. It has been shown that the fundamentals of the HEDG process have been understood through experimental as well as theoretical means and that through the various thermal models used, grinding temperatures can be predicted to give more control over this dynamic process. The main contributions to knowledge are made up of a number of elements within the grinding environment, the most important being the demonstration of the HEDG effect, explanation of the phenomenon and the ability to model the process. It has also been shown that grinding is a dynamic process and factors such as wheel wear will result in a continuous change in the optimum grinding conditions for a given material and wheel combination. With the significance of these factors recognised, they can be accounted for within an industrial adaptive control scenario with the process engineer confident of a more efficient use of time and materials to produce a higher quality product at lower cost. (author)

2002-01-01

272

A critical study of high efficiency deep grinding  

Energy Technology Data Exchange (ETDEWEB)

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, Barkhausen Noise Amplitude (BNA) measurements, surface roughness and Vickers micro-hardness appraisal. It has been shown that the fundamentals of the HEDG process have been understood through experimental as well as theoretical means and that through the various thermal models used, grinding temperatures can be predicted to give more control over this dynamic process. The main contributions to knowledge are made up of a number of elements within the grinding environment, the most important being the demonstration of the HEDG effect, explanation of the phenomenon and the ability to model the process. It has also been shown that grinding is a dynamic process and factors such as wheel wear will result in a continuous change in the optimum grinding conditions for a given material and wheel combination. With the significance of these factors recognised, they can be accounted for within an industrial adaptive control scenario with the process engineer confident of a more efficient use of time and materials to produce a higher quality product at lower cost. (author)

Johnstone, Iain

2002-07-01

273

Heat generated by grinding during removal of ceramic brackets.  

UK PubMed Central (United Kingdom)

When ceramic brackets fracture during treatment or at the time of debonding, it may become necessary to remove residual fragments by grinding with a handpiece. However, the grinding of ceramic surfaces may generate temperatures high enough to have detrimental effects on dental pulp. Intrapulpal temperature measurements were made on extracted teeth during bracket grinding with a small thermocouple probe fixed to the pulpal wall subjacent to the bracket position. These measurements were then compared with established threshold temperatures that have been reported to cause pulpal pathosis. We removed 122 ceramic brackets (A-Company Starfire, GAC Allure, and Unitek Transcend) from eight extracted teeth by grinding with high-speed diamond burs or low-speed green stones, both with and without air or water coolant. It was determined that low-speed grinding without coolant resulted in a significant (p less than 0.001) increase in pulp chamber temperature for all three types of brackets. Neither high-speed nor low-speed grinding during bracket removal caused a rise in pulp chamber temperature when combined with air or water coolant.

Vukovich ME; Wood DP; Daley TD

1991-06-01

274

Torque measurements in rolling mills; Medicao de torque em laminadores  

Energy Technology Data Exchange (ETDEWEB)

This work presents a system for the measuring and torque analysis in steel industry, which has already been proved to present high efficiency. Its application, limitations and peculiarities are described in this work. The system proved to be adequate due to its easy installation, high stability even in adverse conditions and accuracy. 3 refs.

Mendes, Marcelo F. [Penta Consultoria e Montagem Industrial (Brazil)

1989-12-31

275

Preparation and characterization of co-grinded mixtures of aceclofenac and neusilin US2 for dissolution enhancement of aceclofenac.  

Science.gov (United States)

The present study was carried out with a view to enhance the dissolution of poorly water-soluble BCS-class II drug aceclofenac by co-grinding with novel porous carrier Neusilin US(2.) (amorphous microporous granules of magnesium aluminosilicate, Fuji Chemical Industry, Toyama, Japan). Neusilin US(2) has been used as an important pharmaceutical excipient for solubility enhancement. Co-grinding of aceclofenac with Neusilin US(2) in a ratio of 1:5 was carried out by ball milling for 20 h. Samples of co-ground mixtures were withdrawn at the end of every 5 h. and characterized for X-ray powder diffraction, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The analysis revealed the conversion of crystalline aceclofenac to its amorphous form upon milling with Neusilin US(2). Further, in vitro dissolution rate of aceclofenac from co-ground mixture was significantly higher compared to pure aceclofenac. The accelerated stability study of co-ground mixture was carried out at 40 degrees C/75%RH for 4 weeks, and it showed that there was no reversion from amorphous to crystalline form. Thus, it is advantageous to use a porous carrier like Neusilin US(2) in improvement of dissolution of poorly soluble drugs. PMID:19444620

Vadher, Ambarish H; Parikh, Jolly R; Parikh, Rajesh H; Solanki, Ajay B

2009-05-15

276

Amorphization of Indomethacin by Co-Grinding with Neusilin US2: amorphization kinetics, physical stability and mechanism.  

UK PubMed Central (United Kingdom)

PURPOSE: To quantify the effects of the ratio of indomethacin to Neusilin US2 and the processing humidity on the amorphization kinetics, stability and nature of the interaction. MATERIALS AND METHODS: A porcelain jar mill with zirconia balls was used to affect conversion of the physical mixtures (48 g) of indomethacin and Neusilin US2 (in the ratios 1:1 to 1:5) to amorphous states at room temperature (25 degrees C) employing either 0% RH or 75% RH. The percent crystallinity in the samples was determined from ATR-FTIR scans chemometrically. The physical stability of these co-ground amorphous powders was evaluated at 40 degrees C/75% RH and 40 degrees C/0% RH. RESULTS: The lower the ratio of indomethacin to Neusilin US2, the faster is the amorphization during co-grinding. Higher humidity facilitates amorphization with a more pronounced effect at the lower ratio of indomethacin to Neusilin US2. There is further amorphization of some of the partially amorphized samples on storage at 40 degrees C/75% RH for 3 months. Hydrogen bonding and surface interaction between metal ions of Neusilin US2 and indomethacin can explain changes in the FTIR spectra. CONCLUSIONS: The processing humidity and the ratio of indomethacin to Neusilin US2 are important factors to be considered to affect amorphization during ball milling. Amorphous indomethacin can be stabilized by co-grinding with Neusilin US2.

Bahl D; Bogner RH

2006-10-01

277

Preparation and characterization of co-grinded mixtures of aceclofenac and neusilin US2 for dissolution enhancement of aceclofenac.  

UK PubMed Central (United Kingdom)

The present study was carried out with a view to enhance the dissolution of poorly water-soluble BCS-class II drug aceclofenac by co-grinding with novel porous carrier Neusilin US(2.) (amorphous microporous granules of magnesium aluminosilicate, Fuji Chemical Industry, Toyama, Japan). Neusilin US(2) has been used as an important pharmaceutical excipient for solubility enhancement. Co-grinding of aceclofenac with Neusilin US(2) in a ratio of 1:5 was carried out by ball milling for 20 h. Samples of co-ground mixtures were withdrawn at the end of every 5 h. and characterized for X-ray powder diffraction, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The analysis revealed the conversion of crystalline aceclofenac to its amorphous form upon milling with Neusilin US(2). Further, in vitro dissolution rate of aceclofenac from co-ground mixture was significantly higher compared to pure aceclofenac. The accelerated stability study of co-ground mixture was carried out at 40 degrees C/75%RH for 4 weeks, and it showed that there was no reversion from amorphous to crystalline form. Thus, it is advantageous to use a porous carrier like Neusilin US(2) in improvement of dissolution of poorly soluble drugs.

Vadher AH; Parikh JR; Parikh RH; Solanki AB

2009-01-01

278

Hot rolling of intermetallics FeAl phase based alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The one of major problem restricting universal employment of intermetallic phase base alloy istheir low plasticity which leads to hampering their development as construction materials. The following workconcentrates on possibilities to form through rolling process the alloys with various aluminium content.Design/methodology/approach: After casting and annealing, alloy specimens were subjected to axialsymmetriccompression at temperatures ranging from 900 to 1200°C at 10 s-1 strain rates. In order to analyse theprocesses which take place during deformation, the specimens after deformation were intensely cooled with water.Structural examination was carried out using light microscopy. The process was conducted on the K -350 quartorolling mill used for hot rolling of flat products. The process was conducted in some stages in at temperaturesranging from 1200-900°C:Findings: The research carried out enabled the understanding of the phenomena taking place during hot rolling ofthe investigated alloy. An alloy with 38%at. aluminium concentration can be plastically formed at a temperature of upto 900°C, which has been also confirmed in plastometric studies conducted in the form of hot compression tests.Research limitations/implications:Practical implications: The obtained sheets can be used as constructional elements working in complex stressfields, at a high temperature and corrosive environmentsOriginality/value: The tests have shown that it is possible to form the investigated alloys through rolling processingonly where shields are applied. Rolling of the alloys without shields led to the occurrence of a grid of cracks.

G. Niewielski; D. Kuc; I. Schindler; I. Bednarczyk

2008-01-01

279

[Study on grinding of base metal alloys. 4. Constant pressure grinding of a Ni-Cr alloy with vitrified wheels  

UK PubMed Central (United Kingdom)

The grinding techniques and the constituent element of vitrified wheels suitable for a 13% Cr-Ni dental casting alloy were determined. The lever-type grinding test machine used in the previous study was modified so that a work might be ground under a constant pressure as it moved reciprocally within a short stroke along the tangential direction of a rotating wheel. The grinding performance of two marketed wheels and eleven experimental wheels with different constituent elements was tested. Abrasive grains on the working surface of alumina wheel wore extremely due to abrasive attrition. Carborundum wheels proved to be more suitable for grinding of the comparatively soft Ni-Cr alloy. Not only depressing a wheel against a work but also moving the wheel over it with heavier pressure should be desired for the maximal grinding efficiency. The experimental carborundum wheels exhibited much the same performance as the marketed carborundum wheel under a less grinding pressure that 100 gf. Only the wheel of grain size #150 bonded with 19% binder wore obviously under the pressure of 150 or 200 gf and provided about two times the performance of the marketed wheel.

Miyakawa O; Watanabe K; Okawa S; Nakano S; Shiokawa N; Kobayashi M; Tamura H

1989-09-01

280

Skin pass mill tension leveling facility for stainless steel sheets; Stainless kobanyo sukinpasumiru tension leveling setsubi  

Energy Technology Data Exchange (ETDEWEB)

This facility was delivered to Acerinox S.A. (Spain) for surface property improvement, mechanical property improvement and shape correction of bright annealed materials in the end facility of No.3 BAL. Main specifications: (1) Material to be handled: stainless steel sheet (bright annealed cold-rolled steel sheet), (2) Sheet thickness and width: 0.15-2.0mm x 600-1,300mm, (3) Processing speed: 90m/min maximum, (4) Rolling mill: 4 Hi hydraulic depression system, (5) Tension leveler: 6 Hi wet system. Features: (1) Some degree of a flatness only by a skin pass mill through automatic flatness control by work roll bender, 4 Hi skin pass mill with a variable crown backup roll, and shape meter, (2) Stable dead flatness of 0.1% in elongation rate by adding a tension leveler, (3) High-quality bright annealing without any pressed flaw and roll mark by applying an advanced wiper to a skin pass mill, and applying switching control during traveling of welding points to wet leveling and skin pass leveler rolling. (translated by NEDO)

NONE

2000-04-20

 
 
 
 
281

Rolling Stone Rock Guide  

Science.gov (United States)

_Rolling Stone_ magazine and Magellan have teamed up to create this Internet rock resource directory. Whether you want to find out about an artist or a genre of music, obtain tickets for a show, or even gather information on starting your own music career, this site is an excellent starting point. Content for the site is contributed by _Rolling Stone_, but the structure is very similar to Magellan (discussed in the September 1, 1995 Scout Report). The Rock Guide consists of Internet resources that are categorized, reviewed, and rated. Users can browse by genre or search the directory. There are sections on artists, music genres, magazines, books, merchandise, musical instruction, the music business, performances, clubs, online chat and discussion and more.

1996-01-01

282

A modern coal dust grinding and loading plant at Lausitzer Braunkohle AG; Eine moderne Kohlestaubmahl- und -verladeanlage bei der Lausitzer Braunkohle AG  

Energy Technology Data Exchange (ETDEWEB)

The trend towards more economical and efficient combustion and furnace technologies will inevitably require changes in production techniques for lignite products in order to supply fine lignite powders in required qualities. Lausitzer Braunkohle AG at Senftenberg/Germany decided to extend the product range to incorporate a separate fine grinding and storage plant for lignite and also a loading plant in addition to the common technology of a briquette plant where filter dust of the classical briquette production stage is commonly used as lignite powder product only. The entire new plant is controlled automatically. Its annual capacity totals about 520,000 tons of fine lignite powder. The plant includes 10 vibratory mills filled with rods as grinding medium. Pneumatic transportation of lignite powder from the grinding section to the 4 steel storage bins and truck or rail car stations is provided by 3 pumping stations. The entire lignite fine grinding plant and the storage bins as well as the stations were designed, produced, installed and put into operation by AJO-Anlagentechnik of Freudenberg. North-Rhine Westphalia, within a remarkably short time. 6 figs.

Meyer, H.; Mueller-Spaeth, G. [AJO-Anlagentechnik GmbH & Co. KG, Freudenberg (Germany)

1994-01-01

283

Effects of grinding aids on the surface properties of flaky graphite; Rinjo kokuen no hyomen seijo ni ataeru funsai jozai no koka  

Energy Technology Data Exchange (ETDEWEB)

With an objective to obtain a particle shape with thin flaky graphite layer, a dry grinding experiment using a planetary mill was carried out by using metal alkoxides and alcohol-based additives. Investigations were given on their grinding aid effect and effect on the particle shape. As a result of performing the experiment using as additives tri-sec-butylaluminate (coded as A), F-alcohol (coded as B), 1-pentanol (coded as C) and distilled water, the following matters were clarified: A and B addition showed a trend of decreasing deposition strength of the ground materials below that of the case without the addition, and that the ground materials are peeled into thin flakes as they are micronized; the additive B having higher acidity than C showed greater grinding aid effect; dispersing action and grinding accelerating action of graphite powder due to the additives are attributed to reduction in surface energy caused by formation of an adsorption layer on the ground material surface including the new surface; and adsorption and wedging actions of the additive molecules may also be conceived. 22 refs., 6 figs., 1 tab.

Hayashi, T.; Saito, K. [The Nishi-Tokyo University, Yamanashi (Japan). Faculty of Science and Engineering; Hasegawa, T. [Tombow Pencil Co. Ltd., Tokyo (Japan); Tabata, Y. [Nikko Chemicals Co. Ltd., Tokyo (Japan)

1996-03-01

284

Roll of honour  

Energy Technology Data Exchange (ETDEWEB)

This article gives details of the design and construction of dams selected by members of the dam construction industry for praise as feats of construction. The dams covered in the roll of honour include the dam at the Guri hydroelectric power station in Venezuela on the Caroni river, the Contra dam on the Verzrasca river in Switzerland, and the double curvature arc Ertan dam on the Yalong river in China. (UK)

Moxon, Suzanne

1999-07-01

285

New technology to increase lifetimes of wear parts for vertical roller mills; Neue Technologie zur Verlaengerung der Lebensdauer von Verschleissteilen in Vertikal-Rollenmuehlen  

Energy Technology Data Exchange (ETDEWEB)

With the Xwin {sup registered} -technology, it has been possible to substantially increase the lifetime of wear parts in vertical roller mills. This composite material, a combination of high-chromium white iron reinforced with ceramic particles, reaches lifetimes which are in the range of three times higher than ordinary high -chromium castings. With greatly improved lifetimes compared to the above-mentioned materials, total costs for wear parts are reduced and maintenance intervals of wear part replacement are substantially increased as well. The typical wear profile generated by this technology results in a grinding process improvement such as a higher mill throughput or better grind. (orig.)

Velz, Oswald [Magotteaux s.a., Vaux-sous-Chervremont (Belgium); Huelsbusch, Franz-Josef [Infracor GmbH, Marl (Germany)

2010-07-01

286

Hot rolling joining process  

International Nuclear Information System (INIS)

In the case of incorporating nonferrous metal equipment in fuel reprocessing processes, from the viewpoint of reducing maintenance works for the piping connection to peripheral equipments, it is desirable to adopt the pipe joints of joining the materials of different kinds, which have the high reliability against leakage. In order to meet this demand, the development of the manufacturing technology of the pipe joints by hot rolling process has been carried out. As for the structure of this pipe joint, a small diameter nonferrous metal pipe and a large diameter stainless steel pipe are joined by hot rolling by using an inserted material. The materials are Ti-5% Ta, Ti and Zr for the nonferrous metals, SUS 304L for the stainless steel, and Ta foil for the inserted material. The merits and demerits of this pipe joints are shown. The control of the interface structure in the joining of different materials was carried out by using the inserted material. The method of manufacturing the pipe joints and the proper conditions of the rolling joining are explained. As for the performance of the pipe joints, the evaluations of the defects in the joining interface, the strength of the joining, the corrosion resistance and the susceptibility to stress corrosion cracking are reported. (K.I.)

1996-01-01

287

Sensitivity of stress corrosion cracking of stainless steel to surface machining and grinding procedure  

International Nuclear Information System (INIS)

Highlights: ? Pits were more likely to be associated with surface defects induced by machining but tendency was not overwhelming. ? Stress corrosion cracks developed from pits, with cracks emerging both at the surface and within the pit. ? Stress corrosion cracking was attributed to a combination of high tensile residual stress and nanocrystalline layer. ? Stress corrosion cracking was also observed where net stress was compressive; a novel peeling stress effect is proposed. - Abstract: An investigation has been undertaken to establish the effect of surface preparation method on the susceptibility of a 304 stainless steel to stress corrosion cracking under simulated atmospheric corrosion conditions. MgCl2 was deposited onto four-point bend specimens, which were then placed in a chamber with a relative humidity of 45% and temperature of 60 deg. C. These test conditions were designed to reflect external exposure of stainless steel components in industrial plant, including nuclear reactor components, situated in a coastal region, but with the severity of the exposure conditions enhanced to allow discrimination of the effect of surface preparation in a short timescale (up to 1500 h). Four surface preparation methods were evaluated: transverse grinding, longitudinal grinding, transverse dressing using an abrasive flap wheel, and transverse milling. For each case, surface topography, surface defect mapping, near-surface microhardness mapping, residual stress and electron back-scattered diffraction measurements were undertaken. Stress corrosion cracks were observed for the ground and milled specimens but not for the dressed specimens, with cracks apparently originating at corrosion pits. The density of cracks increased in the order: transverse ground, milled and longitudinal ground, with the cracks notably much smaller in length for the transverse ground condition. The propensity for cracking could be linked to the high residual stress and apparent nanocrystalline microstructure at the surface. There was a greater propensity for pitting to initiate at local defect sites on the surface (laps, deeper grooves). However, the tendency was not overwhelming, suggesting that other factors such as more general roughness or the distribution of MnS inclusions had an influence, perhaps reflecting the severity of the environment.

2011-01-01

288

Determining the direction of tooth grinding: an in vitro study.  

UK PubMed Central (United Kingdom)

The analysis of microwear patterns, including scratch types and widths, has enabled reconstruction of the dietary habits and lifestyles of prehistoric and modern humans. The aim of this in vitro study was to determine whether an assessment of microwear features of experimental scratches placed on enamel, perpendicularly to the direction of grinding, could predict the grinding direction. Experimental scratches were placed using a scalpel blade on standardised wear facets that had been prepared by wearing opposing enamel surfaces in an electromechanical tooth wear machine. These control 'baseline' facets (with unworn experimental scratches) were subjected to 50 wear cycles, so that differential microwear could be observed on the leading and trailing edges of the 'final' facets. In Group 1 (n=28), the 'footprint' microwear patterns corresponding to the known grinding direction of specimens in the tooth wear machine were identified. Then, they were used to predict the direction of tooth grinding blindly in the same sample after a 2-week intermission period. To avoid overfitting the predictive model, its sensitivity was also cross-validated in a new sample (Group 2, n=14). A crescent-shaped characteristic observed in most experimental scratches matched the grinding direction on all occasions. The best predictor of the direction of grinding was a combined assessment of the leading edge microwear pattern and the crescent characteristic (82.1% in Group 1 and 92.9% in Group 2). In conclusion, a simple scratch test can determine the direction of tooth grinding with high reliability, although further improvement in sensitivity is desirable.

ten Berge F; te Poel J; Ranjitkar S; Kaidonis JA; Lobbezoo F; Hughes TE; Townsend GC

2012-08-01

289

Winding roll and splicing type winding roll assembly parts  

UK PubMed Central (United Kingdom)

The utility mode provides a winding roll and a spliced winding roll assembly, wherein the winding roll comprises a winding wheel which is used for winding a fish wire and a box body which is matched with the winding wheel the winding wheel is arranged inside the box body and a device for fixing the fish wire is arranged on the box body. The winding roll can also comprise a cover body, and the device for fixing the fish wire is converted to be arranged on the cover body. The spliced winding roll assembly is formed by splicing winding rolls. The winding roll can provide convenience for a user to quickly draw off the fish wire, has good holding function on the fish wire and overcomes the defect that the fish wire is winded with other articles after loosened simultaneously because the box body and the cover body are correspondingly provided with a first clamping part and a second clamping part which are used for clamping, a plurality of winding rolls can be spliced so as to be favorable for storage and transportation and the spliced winding roll assembly has the characteristics of simple structure, small shape, beautiful appearance and so on and has certain economic value and industrial value.

YUEBIN LOU

290

Twin roll casting of magnesium alloys with high aluminum contents  

Directory of Open Access Journals (Sweden)

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.

H. Watari; T. Haga; Y. Shibue; K. Davey; N. Koga

2006-01-01

291

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

Directory of Open Access Journals (Sweden)

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 from 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.

Walter Lindolfo Weingaertner; Adriano Boaron

2012-01-01

292

Rolling as a continuing collision  

CERN Multimedia

We show that two basic mechanical processes, the collision of particles and rolling motion of a sphere on a plane, are intimately related. According to our recent findings, the restitution coefficient for colliding spherical particles \\epsilon, which characterizes the energy loss upon collision, is directly related to the rolling friction coefficient \\mu_{roll} for a viscous sphere on a hard plane. We quantify both coefficients in terms of material constants which allow to determine either of them provided the other is known. This relation between the coefficients may give rise to a novel experimental technique to determine alternatively the coefficient of restitution or the coefficient of rolling friction.

Brilliantov, N V; Brilliantov, Nikolai V.; Poeschel, Thorsten

1999-01-01

293

G-MG Toilet Roll  

Science.gov (United States)

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Picture a roll of toilet paper; assume that the paper in the roll is very tightly rolled. Assuming that the paper in the roll is very thin, find a rela...

294

Potential release of carbon nanotubes from their composites during grinding  

International Nuclear Information System (INIS)

[en] 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.

2013-04-10

295

Rolling cuff flexible bellows  

Energy Technology Data Exchange (ETDEWEB)

A flexible connector apparatus used to join two stiff non-deformable members, such as piping. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.

Lambert, Donald R. (Livermore, CA)

1985-01-01

296

Rolling cuff flexible bellows  

Energy Technology Data Exchange (ETDEWEB)

A flexible connector apparatus used to join two stiff non-deformable members, such as piping. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.

Lambert, D. R.

1985-09-10

297

Microwave treatment of steel mill sludge  

Energy Technology Data Exchange (ETDEWEB)

A microwave-based treatment system for steel mills sludge, produced as a residue of cooling water and lubricating oils from hot strip rolling mills, was announced. The process was developed by the Carnegie Mellon Research Institute; it is said to be 30 times faster than separating the sludge from the liquid in large settling tanks which is the method currently in use. The new method also requires 90 per cent less space and eliminates land-filling by producing material of value. The proposed method was reviewed by the American Iron and Steel Institute (AISI), and pronounced by them to be far superior to any other currently used technique. Work is underway to improve the process to treat waste liquids containing polymers. 11 refs., 3 tabs., 7 figs.

Goodwill, J. E.; Purta, D. A. [EPRI Center for Materials Production, Carnegie Mellon Research Institute, Pittsburgh, PA (United States)

1994-12-31

298

Performance analysis of magnesium phosphate cement mortar containing grinding dust  

Directory of Open Access Journals (Sweden)

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

Daniel Véras Ribeiro; Márcio Raymundo Morelli

2009-01-01

299

Performance analysis of magnesium phosphate cement mortar containing grinding dust  

Scientific Electronic Library Online (English)

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

Ribeiro, Daniel Véras; Morelli, Márcio Raymundo

2009-03-01

300

Study of thresholds to burning in surface grinding process  

Directory of Open Access Journals (Sweden)

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.

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

2005-01-01

 
 
 
 
301

Efficient grinding and polishing processes for asphere manufacturing  

Science.gov (United States)

The increasing use of aspheres in a variety of optical systems has pushed the industry to become more efficient at its manufacturing processes. Non-optimized grinding techniques can cause excessive sub-surface damage and mid-spatial frequency errors which can be both time consuming and difficult to remove during polishing. The SCGa 100 grinder and SCPa 100 polisher provide unique platforms for asphere manufacturing. The SCGa 100 uses optimized kinematics to create a stiff and rigid platform which minimizes grinding errors and artifacts. Subsequently, polishing time on the SCPa 100 is decreased reducing the risk of altering the aspheric shape. This process improves surface quality while simplifying manufacturing.

Hinn, Markus; Pisarski, Alex

2013-09-01

302

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.)

2007-01-01

303

Continuous manufacturing line using micro mill for gas shielded metal arc welding wire; Micro mill wo mochiita gas shield arc yosetsuyo solid wire renzoku seizo line  

Energy Technology Data Exchange (ETDEWEB)

The present paper introduced the continuous manufacturing line of which the main part is a micro mill to manufacture, with high efficiency, the solid wire for the gas shielded metal arc welding. It is a continuous process composed of rough drawing, annealing and copper plating. For the rough drawing, a three-roll rolling micro mill was introduced from Continuous Corp., Italy. The conventional wire drawing with die was limited in drawing speed for the exothermic reason. The speed could be then heightened up to 500m/min by the rolling with rolls. The superhard roll was originally developed by taking, into consideration, the hardness, compressive strength and transverse rupture strength, so that the roll life became about two times as long as the conventional one. With the raw rod diameter enlarged from 5.5mm to 7.0mm, the material cost could be lowered by specifying the rolling path schedule and cooling condition with lubricating oil. The working environment was considerably improved by simplifying the pay-off operation and preventing the dust from dispersing. The operation could be made stable through the productivity heightened by making the speed high and the process continuous. 3 refs., 12 figs., 3 tabs.

Takahashi, N.; Yamanaka, E.; Nakagawa, Y. [Kawasaki Steel Corp., Tokyo (Japan)

1995-01-01

304

Development of industrial production of ultrafine grained steel in tandem hot strip mill; Production industrielle d'acier a grain ultra-fin au train a bandes  

Energy Technology Data Exchange (ETDEWEB)

Based on a model of microstructure evolution, an appropriate rolling schedule has been worked out to produce ultrafine grained steel (2 to 5 {mu}m) on the hot strip mill. This rolling schedule is characterized by a large reduction in the finishers followed by strong cooling. Implementing such a rolling schedule on a conventional HSM raises major problems: increased rolling torque and force, lowered crown and shape control, disturbed looper control, accelerated roll damage, increased slip between strip and roll, insufficient cooling efficiency. These problems have been solved on the new Nakayama HSM by introducing innovative processes such as: single roll drive with different diameter and a new CVC, curtain wall cooling in the finisher, low inertia hydraulic looper, new high-speed steel rolls with solid lubrication. (authors)

Kurahashi, R.; Hakomori, K.; Chikushi, I.; Morimoto, T. [Nakayama Steel Works, Ltd. (Japan); Yanagimoto, J. [Tokyo Univ. (Japan); Takaoka, S. [Kawasaki Heavy Industries Ltd., Kobe (Japan)

2005-04-01

305

Numerical simulation of a hot rolling process  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the findings of the effects of rolling parameters on the work roll undergoing thermal cycles through numerical simulation using the finite element method. The rolling parameters investigated are the location of the spray nozzle, the coolant spray flux, and the initial work roll temperature. The findings show that the spray nozzle is best placed near the exit of the roll bite for minimum fatigue stress. Firecracking can be eliminated by providing a large cooling flux through spraying. The initial temperature of the work roll have little effect on the roll life, but does have some influence on the quality of the rolled product.

Tso, C.P.; Tan, F.L.

1999-07-01

306

Global analysis of aerodynamics deflectors efficiency in the grinding process  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 workpiece surface. The optimization can happen through the correct selection of the cut parameters and development of devices that eliminate air layer effects generated around t (more) he 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.

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

2006-06-01

307

Global analysis of aerodynamics deflectors efficiency in the grinding process  

Directory of Open Access Journals (Sweden)

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 workpiece 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.

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

2006-01-01

308

Attrition grinding of coal in the presence of polymeric additives  

Energy Technology Data Exchange (ETDEWEB)

The effect of poly(acrylic acid), poly(acrylamide), and poly(vinyl alcohol) on the attrition grinding of Illinois No. 6 coal was examined. The grinding efficiency was significantly increased by poly(acrylic acid), slightly decreased by poly(acrylamide), and unaffected by poly(vinyl alcohol). The beneficial effect of poly(acrylic acid) was most pronounced when it was used as an additive in a 55% solids slurry. The beneficial effect decreased with increasing grinding time and was most effective at lower pH values where the poly(acrylic acid) existed in the acid or partially neutralized form. When the mixture of coal slurry plus poly(acrylic acid) was neutralized with alkali to pH 6.62, the beneficial effect disappeared. Subsequent froth flotation, using kerosene and MIBC, of coal ground with poly(acrylic acid) was essentially unaffected by the presence of the additive. Some potential economic advantages of using poly(acrylic acid) as a grinding aid are pointed out. 15 refs., 3 figs., 4 tabs.

Liu, D.-C.; Birlingmair, D.H.; Burkhart, L.E.; Markuszewski, R.

1989-01-01

309

The Graduate Grind: A Critical Look at Graduate Education  

Directory of Open Access Journals (Sweden)

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.

Annabelle L. Grundy; Michelle K. McGinn

2003-01-01

310

The Graduate Grind: A Critical Look at Graduate Education  

Directory of Open Access Journals (Sweden)

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.

Annabelle L. Grundy; Michelle K. McGinn

2010-01-01

311

Coking charge components pneumatic separation before final grinding  

Energy Technology Data Exchange (ETDEWEB)

This work presents the pilot scale experiments to establish the optimum coking charge components grain size. At the same time, a pneumatic separation of that initial coal grain size was tried before the final grinding. The method involves: improving the coke quality and productivity, assuring also energy saving etc., 1 fig., 1 tab.

Albastroiu, P.; Cadar, G.; Lambescu, S.; Hrebenciuc, M.; Popescu, D.; Dinu, I. [Metallurgical Research Institute, Bucharest (Romania)

1998-07-01

312

Grinding performance of pellet prepared using nanosize ceria particles  

Energy Technology Data Exchange (ETDEWEB)

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.

Oshita, T. [Development and Technology Division, Hitach Maxell, Ltd., 1 Koizumi, Oyamazaki, Otokuni-gun, Kyoto 618-8525 (Japan)]. E-mail: tadashi-oshita@maxell.co.jp; Sawaki, Y. [Development and Technology Division, Hitach Maxell, Ltd., 1 Koizumi, Oyamazaki, Otokuni-gun, Kyoto 618-8525 (Japan); Kishimoto, M. [Development and Technology Division, Hitach Maxell, Ltd., 1 Koizumi, Oyamazaki, Otokuni-gun, Kyoto 618-8525 (Japan)

2006-02-09

313

Variability in hand-arm vibration during grinding operations.  

UK PubMed Central (United Kingdom)

BACKGROUND: Measurements of exposure to vibrations from hand-held tools are often conducted on a single occasion. However, repeated measurements may be crucial for estimating the actual dose with good precision. In addition, knowledge of determinants of exposure could be used to improve working conditions. The aim of this study was to assess hand-arm vibration (HAV) exposure during different grinding operations, in order to obtain estimates of the variance components and to evaluate the effect of work postures. METHODS: Ten experienced operators used two compressed air-driven angle grinders of the same make in a simulated work task at a workplace. One part of the study consisted of using a grinder while assuming two different working postures: at a standard work bench (low) and on a wall with arms elevated and the work area adjusted to each operator's height (high). The workers repeated the task three times. In another part of the study, investigating the wheel wear, for each grinder, the operators used two new grinding wheels and with each wheel the operator performed two consecutive 1-min grinding tasks. Both grinding tasks were conducted on weld puddles of mild steel on a piece of mild steel. Measurements were taken according to ISO-standard 5349 [the equivalent hand-arm-weighted acceleration (m s(-2)) averaged over 1 min]. Mixed- and random-effects models were used to investigate the influence of the fixed variables and to estimate variance components. RESULTS: The equivalent hand-arm-weighted acceleration assessed when the task was performed on the bench and at the wall was 3.2 and 3.3 m s(-2), respectively. In the mixed-effects model, work posture was not a significant variable. The variables 'operator' and 'grinder' together explained only 12% of the exposure variability and 'grinding wheel' explained 47%; the residual variability of 41% remained unexplained. When the effect of grinding wheel wear was investigated in the random-effects model, 37% of the variability was associated with the wheel while minimal variability was associated with the operator or the grinder and 37% was unexplained. The interaction effect of grinder and operator explained 18% of the variability. In the wheel wear test, the equivalent hand-arm-weighted accelerations for Grinder 1 during the first and second grinding minutes were 3.4 and 2.9 m s(-2), respectively, and for Grinder 2, they were 3.1 and 2.9 m s(-2), respectively. For Grinder 1, the equivalent hand-arm-weighted acceleration during the first grinding minute was significantly higher (P = 0.04) than during the second minute. CONCLUSIONS: Work posture during grinding operations does not appear to affect the level of HAV. Grinding wheels explained much of the variability in this study, but almost 40% of the variance remained unexplained. The considerable variability in the equivalent hand-arm-weighted acceleration has an impact on the risk assessment at both the group and the individual level.

Liljelind I; Wahlström J; Nilsson L; Toomingas A; Burström L

2011-04-01

314

Production of normalized steel plate through normalizing rolling; Producao de chapas grossas normalizadas diretamente do calor de laminacao  

Energy Technology Data Exchange (ETDEWEB)

Normalized plates can be got directly from the rolling heat through the use of a normalizing rolling process. In such way, an additional step of the conventional process of production of normalized plates - the normalizing heat treatment - can be suppressed, reducing the manufacturing cost of the product and shortening its production time. This relatively new production route is being used in several steelworks all over the world for many years. This work describes the implementation trials of normalizing rolling at COSIPA`s plate mill, using an alternative process of controlled rolling called recrystallization controlled rolling. The results got with new technique were successful, as it was able to produce plates with properties very similar to the conventionally normalized material, attending the requirements of the DIN 17100 RR 52-3N standard. This is one of many standards that permit the use of this new route of normalized steel plate production. (author) 14 refs., 8 figs., 2 tabs.

Gorni, Antonio Augusto; Cavalcanti, Celso Gomes; Reis, Jackson Soares de Souza; Silveira, Jose Herbert Dolabela da [Companhia Siderurgica Paulista (COSIPA), SP (Brazil)

1997-12-31

315

Determination of the energy and power parameters during groove-rolling  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In order to correctly design the process of bar rolling in grooves it is required that several limitations affecting the rolling process be considered. When developing a technology, energy and force parameters, among others, are needed to be taken into account. Therefore, it is purposeful to examine variations in the energy and force parameters during the rolling of bars.Design/methodology/approach: Using FEM-based computer programs for solving the problems of the theory of plasticity enables determining the energy and force parameters in complex plastic working processes and also accounting for a number of process specificities, which are not provided for by the empirical formula.Findings: The theoretical values of the rolling torque and power during the rolling of band in the grooves, as determined using the Forge3® software and the engineering method proposed by Chekmarev, were compared with the experimental values obtained from the measurements of current loads in a plant manufacturing bars. The current loads of the main drive of the continuous rolling mill for rolling bars were measured in one of the Polish steelworks.Practical implications: Change in the band temperature over its length influences the variations in the magnitudes of widening and advance. Its variations lead to a change in energy–force parameters.Originality/value: Using the FE programs for the computation of the values of the energy–force parameters can take into account the distribution of temperature over the band length.

S. Mróz; K. Jagie?a; H. Dyja

2007-01-01

316

Comminution practices  

Energy Technology Data Exchange (ETDEWEB)

The Proceedings of a Comminution Practices Symposium held February 24-27, 1997 in Denver Colorado are presented. The symposium covered such topics as: grinding circuits; comminution process control and instrumentation; high pressure grinding rolls; fine grinding; recycling; and mill design. Separate abstracts were prepared for three of the papers for inclusion in the Energy Science and Technology Database.

Kawatra, S.K. [ed.

1997-11-01

317

Characterization of roll bite heat transfers in hot steel strip rolling and their influence on roll thermal fatigue degradation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A temperature sensor with a thermocouple placed at ~0.5 mm from roll surface is used in hot rolling conditions to evaluate by inverse calculation heat transfers in the roll bite. Simulation analysis under industrial hot rolling conditions with short contact lengths (e.g. short contact times) and hig...

LEGRAND, Nicolas; Weisz-Patrault, Daniel; Horsky, Jaroslav; Luks, Tomas; Labbe, Nathalie; Picard, Michel; Ehrlacher, Alain

318

Analysis of roll gap heat transfers in hot steel strip rolling through roll temperature sensors and heat transfer models  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents an analysis of roll bite heat transfers during pilot hot steel strip rolling. Two types of temperature sensors (drilled and slot sensors) implemented near roll surface are used with heat transfer models to identify interfacial heat flux, roll surface temperature and Heat Transfer...

Weisz-Patrault, Daniel; Ehrlacher, Alain; LEGRAND, Nicolas; Labbe, Nathalie; Horsky, Jaroslav; Luks, Tomas

319

"AMINAT" ROLL PRESERVE PREPARATION METHOD  

UK PubMed Central (United Kingdom)

FIELD: food production process. ^ SUBSTANCE: preserves are prepared by cutting and freezing cilantro, grating brynza and mixing of the listed components with cooking salt, khmeli-suneli and red hot pepper to obtain mince, beating chicken fillet, putting on it mince and rolling them to prepare rolls, cutting and freezing green onion and mixing without oxygen access with cooking salt and calcium ascorbate to prepare garnish, packing rolls, garnish and chicken stock, sealing and sterilising. ^ EFFECT: diversification of available food products improved digestibility of preserve foods as compared to standard analogues.

KVASENKOV OLEG IVANOVICH

320

The influence of tandem rolling process parameters on the texture and earing behaviour of AA1050  

Energy Technology Data Exchange (ETDEWEB)

A novel combination of techniques, namely hot plane-strain compression (PSC) tests and laboratory cold rolling, was successfully applied to simulate the industrial practice for producing AA1050 sheets. Starting material for testing was taken from a hot rolled plate at transfer gauge between the breakdown and tandem mill. Three-stand hot tandem-rolling was simulated by means of hot plane-strain compression tests using a thermal mechanical treatment simulator (TMTS). Coil-cooling was simulated by means of a controlled cooling in a furnace. The hot deformed material was subsequently cold rolled on a laboratory mill. The influence of tandem rolling process parameters, such as entry temperature and strain rate on textures in different conditions and on the earing in the final annealed condition was investigated. A good agreement in the texture and earing values was found between the PSC-material and the production material, which makes this combination of techniques as a valuable way to evaluate the influences of industrial processing parameters on the final properties. It was found that the entry temperature has a stronger effect on the texture and earing than the strain rate. (orig.)

Liu, C.; Zhuang, L.; Winden, M.R. van der; Hurd, T.J. [Corus Research, Development and Technology, Ijmuiden (Netherlands)

2002-07-01

 
 
 
 
321

THE STUDY OF SCALE FORMATION ON HOT ROLLED INGOTS AND BILLETS  

Directory of Open Access Journals (Sweden)

Full Text Available During the heating for rolling, ingots and billets are affected by the chemical action of the heating atmosphere. Between the heating environment elements and steel components there are taking place chemical reactions initiated at the separation surface that may affect a layer in metal of about a few microns to a few millimeters. The thickness of the affected layer is a function of the environment nature, heated material composition, chemical reaction’s type and kinetics, heating rate and temperature. The aim of this paper is to correlate the oxidation and the decarburization processes during the heating of ingots and billets for rolling. The study was made on ingots and billets rolled at the breakdown mill of the Special Steel Complex, Physics Laboratories from MECHEL Targoviste, Romania. The scope of the study is the analysis of the scale obtained from the rolling mill train in order to obtain specific information that will be used in adjusting the rolling parameters for diminishing the oxidation and decarburization and for recycling the scale in electric furnaces.

GHEORGHE VLAICU; IULIAN BANCUTA; CLAUDIA STIHI; GABRIEL STATE; ANCA GHEBOIANU

2010-01-01

322

Control rolling and cooling for on-line production of strong, tough steels  

Energy Technology Data Exchange (ETDEWEB)

Strong tough steels have been designed to produce microcomposite structures of fine grained auto-tempered lath martensite with untransformed austenite films between the laths. Such structures can be produced on-line in a hot mill by controlled rolling and cooling. The steels are based on Fe/Cr/Mn/C compositions which can be air hardenable, or for lean compositions, water quench hardened with Nb microalloying. The steels have excellent mechanical properties that are superior to current HSLA steels and require no subsequent heat treatment following rolling and cooling. Successful commercial plate trials have occurred. 18 refs., 11 figs., 1 tab.

Thomas, G.

1988-11-01

323

Roll Damping at Forward Speed.  

Science.gov (United States)

Three dimensional body theories indicate a significant effect of forward speed on the linear roll damping coefficient, whereas two dimensional and strip-slender body theories indicate that the effect is small. Model tests, carried out many years ago, demo...

M. A. Abkowitz

1983-01-01

324

A mould for bread rolls  

UK PubMed Central (United Kingdom)

Mould of an array of moulds for making bread rolls comprises two parts, one of which contains a cavity 7 and the other of which contains a cap 3 with a former 4 extending therefrom. In use, a quantity of dough is placed in the cavity 7 and the cap 3 put over the open end with the former 4 extending into the cavity 7. The dough is then allowed to prove around the former, and the entire mould is then baked in an oven. The bread rolls made in this way are shaped according to the shape of the cavity and are penetrated by a hole. Since the hole is baked into the roll the entire interior surface of the hole, as well as the entire exterior of the roll, are crusted.

RYAN LAWRENCE JOHN

325

Grease lubrication in rolling bearings  

CERN Multimedia

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

Lugt, Piet M

2012-01-01

326

Machining and grinding: High rate deformation in practice  

Energy Technology Data Exchange (ETDEWEB)

Machining and grinding are well-established material-working operations involving highly non-uniform deformation and failure processes. A typical machining operation is characterized by uncertain boundary conditions (e.g.,surface interactions), three-dimensional stress states, large strains, high strain rates, non-uniform temperatures, highly localized deformations, and failure by both nominally ductile and brittle mechanisms. While machining and grinding are thought to be dominated by empiricism, even a cursory inspection leads one to the conclusion that this results more from necessity arising out of the complicated and highly interdisciplinary nature of the processes than from the lack thereof. With these conditions in mind, the purpose of this paper is to outline the current understanding of strain rate effects in metals.

Follansbee, P.S.

1993-01-01

327

Machining and grinding: High rate deformation in practice  

Energy Technology Data Exchange (ETDEWEB)

Machining and grinding are well-established material-working operations involving highly non-uniform deformation and failure processes. A typical machining operation is characterized by uncertain boundary conditions (e.g.,surface interactions), three-dimensional stress states, large strains, high strain rates, non-uniform temperatures, highly localized deformations, and failure by both nominally ductile and brittle mechanisms. While machining and grinding are thought to be dominated by empiricism, even a cursory inspection leads one to the conclusion that this results more from necessity arising out of the complicated and highly interdisciplinary nature of the processes than from the lack thereof. With these conditions in mind, the purpose of this paper is to outline the current understanding of strain rate effects in metals.

Follansbee, P.S.

1993-04-01

328

[Influence of superfine grinding on micromeritic properties of Scutellaria baicalensis].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To study the micromeritic properties of different particle size of Scutellaria baicalensis and provide a basis for being directly used or as raw material of Chinese herba preparation. METHODS: Size distribution, surface area and pore volume, contact angle, angle of repose and bulk density, moisture absorption, micromorphology, Infrared spectrum, HPLC fingerprint were used to evaluate the differences of micromeritic properties of 4 kinds of Scutellaria baicalensis superfine grinding. RESULTS: With the particle size of powders decreased, size distribution and bulk density decreased, the surface area and pore volume, contact angle and moisture absorption increased, angle of repose first increased and then decreased. Infrared spectrum and HPLC fingerprint showed no change of chemical composition of Scutellaria baicalensis. CONCLUSION: Different particle size of Scutellaria baicalensis leads to the differences of micromeritic properties. Superfine grinding III is determined as a better particle size.

Wang NM; Zhang DK; Yang M; Qin CF; Han L; Su ZT; Guo ZP

2013-04-01

329

METHOD FOR THE REACTIVE GRINDING OF CASTOR SEEDS  

UK PubMed Central (United Kingdom)

The present invention relates to a method for the reactive grinding of castor seeds which, using specially processed castor seeds in the presence of a light alcohol and a basic catalyst, enables a grinding and a transesterification reaction of the triglycerides present in the castor oil to be performed in a single step, simultaneously producing an oil cake, glycerol and fatty acid esters, in particular ricinoleic acid. In a straightforward, inexpensive manner, the method for treating castor seeds according to the invention inactivates, in addition to the castor oil, the powerful allergen CB-IA, thus enabling risk-free handling by humans as well as the use of castor oil cakes as animal feed. Characteristically, the grains are processed by a series of operations including a step of flattening and a step of drying said grains.

DUBOIS JEAN-LUC; MAGNE JULIEN; BARBIER JACQUES; PICCIRILLI ANTOINE

330

Teeth Grinding: Is Emotional Stability related to Bruxism?  

UK PubMed Central (United Kingdom)

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

Sutin AR; Terracciano A; Ferrucci L; Costa PT Jr

2010-06-01

331

High coercivity induced by mechanical milling in cobalt ferrite powders  

Science.gov (United States)

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.

Ponce, A. S.; Chagas, E. F.; Prado, R. J.; Fernandes, C. H. M.; Terezo, A. J.; Baggio-Saitovitch, E.

2013-10-01

332

In-process grinding monitoring through acoustic emission  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 (more) 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.

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

2006-03-01

333

Cooking and grinding reduces the cost of meat digestion.  

UK PubMed Central (United Kingdom)

The cooking of food is hypothesized to have played a major role in human evolution partly by providing an increase in net energy gain. For meat, cooking compromises the structural integrity of the tissue by gelatinizing the collagen. Hence, cooked meat should take less effort to digest compared to raw meat. Likewise, less energy would be expended digesting ground meat compared to intact meat. We tested these hypotheses by assessing how the cooking and/or grinding of meat influences the energy expended on its digestion, absorption, and assimilation (i.e., specific dynamic action, SDA) using the Burmese python, Python molurus. Pythons were fed one of four experimental diets each weighing 25% of the snake's body mass: intact raw beef, intact cooked beef, ground raw beef, and ground cooked beef. We measured oxygen consumption rates of snakes prior to and up to 14 days following feeding and calculated SDA from the extra oxygen consumed above standard metabolic rate. Postprandial peak in oxygen consumption, the scope of peak rates, and SDA varied significantly among meal treatments. Pythons digesting raw or intact meals exhibited significantly larger postprandial metabolic responses than snakes digesting the cooked ground meals. We found cooking to decrease SDA by 12.7%, grinding to decrease SDA by 12.4%, and the combination of the two (cooking and grinding) to have an additive effect, decreasing SDA by 23.4%. These results support the hypothesis that the consumption of cooked meat provides an energetic benefit over the consumption of raw meat.

Boback SM; Cox CL; Ott BD; Carmody R; Wrangham RW; Secor SM

2007-11-01

334

Cooking and grinding reduces the cost of meat digestion.  

Science.gov (United States)

The cooking of food is hypothesized to have played a major role in human evolution partly by providing an increase in net energy gain. For meat, cooking compromises the structural integrity of the tissue by gelatinizing the collagen. Hence, cooked meat should take less effort to digest compared to raw meat. Likewise, less energy would be expended digesting ground meat compared to intact meat. We tested these hypotheses by assessing how the cooking and/or grinding of meat influences the energy expended on its digestion, absorption, and assimilation (i.e., specific dynamic action, SDA) using the Burmese python, Python molurus. Pythons were fed one of four experimental diets each weighing 25% of the snake's body mass: intact raw beef, intact cooked beef, ground raw beef, and ground cooked beef. We measured oxygen consumption rates of snakes prior to and up to 14 days following feeding and calculated SDA from the extra oxygen consumed above standard metabolic rate. Postprandial peak in oxygen consumption, the scope of peak rates, and SDA varied significantly among meal treatments. Pythons digesting raw or intact meals exhibited significantly larger postprandial metabolic responses than snakes digesting the cooked ground meals. We found cooking to decrease SDA by 12.7%, grinding to decrease SDA by 12.4%, and the combination of the two (cooking and grinding) to have an additive effect, decreasing SDA by 23.4%. These results support the hypothesis that the consumption of cooked meat provides an energetic benefit over the consumption of raw meat. PMID:17827047

Boback, Scott M; Cox, Christian L; Ott, Brian D; Carmody, Rachel; Wrangham, Richard W; Secor, Stephen M

2007-08-16

335

Can seeds help mice with the daily grind?  

Science.gov (United States)

Some laboratory mice gnaw food pellets without ingesting much of the gnawed material, resulting in the production of waste material called 'orts'. The fact that this food grinding behavior is not seen in all individuals of a particular strain suggests that it might be abnormal, and thus indicate a welfare concern. Furthermore, the increased rate of feed consumption and cage soiling is undesirable from a husbandry perspective. To try to determine possible motivations for the behavior, and identify potential treatments, outbred Crl:CD1(Icr) mice exhibiting food grinding were selected for one of three treatments placed in the feeder: no enrichment, a chewing device, or sunflower seeds. Both enrichment groups showed a significant decrease (P?food wastage after the treatment was withdrawn. A relationship between body weight and ort production was also found, in that cages with greater average body weights had lower levels of ort production. This suggests that a simple need to gnaw cannot alone explain food grinding, and that a nutritional motivation may also be involved. PMID:23760566

Pritchett-Corning, Kr; Keefe, R; Garner, Jp; Gaskill, Bn

2013-06-10

336

Thorium exposure during welding and grinding with thoriated tungsten electrodes  

International Nuclear Information System (INIS)

[en] Applying Tungsten Inert Gas (TIG) shielded welding process, often thoriated tungsten electrodes are used. Thorium is added to facilitate arc starting and to increase the arc's stability. If the electrode is touched down on the workpiece - not standing for a proper use but not always to avoid - a part of it will be vaporized. In the course of this, thorium will be emitted. Only a sharp electrode will guaranty the wanted quality. Therefore the welder had to grind the electrode from time to time, also emitting thorium in breathable form. The presented contribution gives an overview about the results of numerous personal measurements of airborne activity concentration during grinding and welding. Under proper use of thoriated electrodes at welding airborne activity (Th-232) of up to 2.6 mBq/m3 were found. This leads to an maximum annual body burden of 1.5 Bq. This is far below the limits of German regulations of non radiation workers. During grinding activity concentrations up to 0.5 Bq/m3 were measured. Even taking realistic annual working time into account limit may be exceeded. Radiation protection measures are to be enhanced, suggestions are made. (author)

1996-01-01

337

Can seeds help mice with the daily grind?  

UK PubMed Central (United Kingdom)

Some laboratory mice gnaw food pellets without ingesting much of the gnawed material, resulting in the production of waste material called 'orts'. The fact that this food grinding behavior is not seen in all individuals of a particular strain suggests that it might be abnormal, and thus indicate a welfare concern. Furthermore, the increased rate of feed consumption and cage soiling is undesirable from a husbandry perspective. To try to determine possible motivations for the behavior, and identify potential treatments, outbred Crl:CD1(Icr) mice exhibiting food grinding were selected for one of three treatments placed in the feeder: no enrichment, a chewing device, or sunflower seeds. Both enrichment groups showed a significant decrease (P < 0.05) in ort production when compared with baseline measurements, but only mice provided with sunflower seeds maintained the decreased rate of food wastage after the treatment was withdrawn. A relationship between body weight and ort production was also found, in that cages with greater average body weights had lower levels of ort production. This suggests that a simple need to gnaw cannot alone explain food grinding, and that a nutritional motivation may also be involved.

Pritchett-Corning KR; Keefe R; Garner JP; Gaskill BN

2013-10-01

338

The Effect of Moisture Content on Determining Corn Hardness from Grinding Time and Grinding Energy, and Hardness Prediction Using Near-Infrared Spectroscopy  

Science.gov (United States)

The Stenvert hardness test was used to determine the energy-to-grind (ETG) and time-to-grind (TTG) of 107 food-grade corn hybrids at different moisture content (MC) levels. ETG and TTG were significantly affected by moisture content. Across hybrids, ETG displayed the most consistent response to MC...

339

Direct measures of mechanical energy for knife mill size reduction  

Energy Technology Data Exchange (ETDEWEB)

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.

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

340

Features of the latest high-speed wire rod mill line; Saishin no kaigaimuke senzai atsuen setsubi no tokucho  

Energy Technology Data Exchange (ETDEWEB)

High-speed wire rod mills have been introduced since 1965 for improving productivity of wire rod rolling lines in Japan. In response to subsequent requirements for further improvement of productivity, operational finishing speed over 100 m/s has been realized, which was initially 60 m/s. Further high-speed operation is to be realized in the future. However, for stable operation in the high-speed rolling, more advanced operational technology and safety technology of rolling are indispensable. Especially, techniques of skilled operators are required for the operations of high-speed wire rod block mill. Since it is hard to ensure such highly skillful operators, high-speed rod mill lines with easy operation are also required. This paper introduces an outline of wire rod mill lines with high-speed block mill (S-HUM) which have been developed and exported under such circumstances, and features of the high-speed block mill. For high-speed wire rod mills delivered to Taiwan, production of high productivity and high quality products has been started with short period startup with less investment. 4 refs., 12 figs.

Nakatani, M. [Kobe Steel, Ltd., Kobe (Japan)

1998-04-01

 
 
 
 
341

John Stuart Mill Links  

Science.gov (United States)

Considered one of the most important philosophers of the 19th century, John Stuart Mill was born in 1806 to one James Mill, part-time philosopher and economist, and full-time official in the East India Company. Educated by both his father and the philosopher Jeremy Bentham, Mill learned Greek by age three, Latin shortly thereafter, and was a competent logician by age 12. After suffering a mental breakdown at the age of 20, Mill decided he would commit himself to persuading the general public of the need for a scientific and rational approach to understanding social, political, and economic change. Mill penned some of the most powerful statements on the behalf of utilitarianism during his life, including one of his most enduring works, Utilitarianism. This Web site (offered in numerous different languages) is a compilation of links to works by and about Mill, including full-text versions of such works as On Liberty, Principles of Political Economy, and his Autobiography. Equally compelling are the works about Mill also to be found here, most notably Isaiah Berlin's 1959 article, John Stuart Mill and the Ends of Life.

342

Deformation behaviour of duplex stainless steel during industrial hot rolling  

Energy Technology Data Exchange (ETDEWEB)

Industrially processed duplex stainless steel sheet was investigated after the reheating, the roughing mill and the finishing rolling. Light optical microscopy revealed that the cast structure that existed before rolling was removed and changed into a banded microstructure. During the process, the ferrite-austenite volume fraction ratio changed from 72%{alpha} + 28%{gamma} to 48%{alpha} + 52%{gamma}. The microhardness was measured for both phases after each process step. Texture measurements were executed by means of the electron backscattering diffraction technique (EBSD). These measurements revealed that extensive static recrystallisation of the austenite occurred during the roughing but that recrystallisation was inhibited during the finishing. Transmission electron microscopy (TEM) on the finish rolled material indicated that the ferrite softened efficiently by extended dynamic recovery. The dislocations in ferrite grains with rotated cube orientation were often found to be straight screw dislocations which were inclined 55 Cto the surface of the sheet. The importance of the partitioning of the alloying elements and the strain partitioning on the deformation behaviour is highlighted. (orig.)

Duprez, L.; Cooman, B.C. de [Lab. for Iron and Steelmaking (LISm), Ghent Univ., Ghent (Belgium); Akdut, N. [Ocas N.V., Research Center of the Sidmar Group, Zelzate (Belgium)

2002-12-01

343

Calculation and Analysis of Temperature Distribution in Hot Rolling Strip  

Directory of Open Access Journals (Sweden)

Full Text Available Modern steel grades require constant and reproducible production conditions both in the hot strip mill and in the cooling section to achieve constant material properties along the entire strip length and from strip to strip. Calculation of the temperature in final rolling process always utilizes factors such as the work piece's inner organizational structure, plastic deformation, and it's variations of properties and so on, also as well as the physical parameters such as gauge, shape, etc. In this paper, a finite element model is constructed for the temperature field in a rolling process. The temperature field of strip steel is modeled with a 3-D finite element analysis (FEA) structure, simultaneously considering the distribution of the work roll temperature. Then the distribution of field is simulated numerically. From the model, the temperature contours can be obtained by analysis of the temperature distribution of contact area. At the same time, the distribution of temperature in any position at any time can be acquired. These efforts provide the reliable parameters for the later finishing temperature and shape control.  

Kaixiang Peng

2013-01-01

344

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)

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)

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

345

Using CCT diagrams to optimize the composition of an As-rolled dual-phase steel  

Energy Technology Data Exchange (ETDEWEB)

A continuous-cooling transformation (CCT) diagram study was conducted for the purpose of optimizing the composition of an Mn-Si-Cr-Mo as-rolled dual-phase (ARDP) steel. The individual effects of chromium, molybdenum, and silicon on the allowable cooling rates were determined. On the basis of the CCT diagram study and other available information, an optimum composition was selected. Data from recent mill trials at three steel companies, involving steels with compositions in or near the newly recommended range, are presented and compared with earlier mill trial data. The comparison shows that the optimized composition is highly effective in making the steel's properties more uniform and reproducible in the as-rolled condition.

Coldren, A.P.; Eldis, G.T.

1980-03-01

346

Mathematical simulation of controlled cooling for high speed rolled wire in Stelmor process  

International Nuclear Information System (INIS)

Mathematical models have been developed to predict the temperature distribution and austenite - pearlite transformation kinetics during the processing of high carbon steel wire in a stelmor machine. For a given rod radius there are three critical fans whose mechanical efficiency should be periodically reviewed to maintain constant cooling condition. These models are currently being applied for rod production control at the transformation at the conveyor of Tangshan Iron and Steel Co. Ltd., High Speed Wire Rod Rolling Mill, China. (author)

2000-01-01

347

Mathematical simulation of controlled cooling for high speed rolled wire in Stelmor process  

Energy Technology Data Exchange (ETDEWEB)

Mathematical models have been developed to predict the temperature distribution and austenite - pearlite transformation kinetics during the processing of high carbon steel wire in a stelmor machine. For a given rod radius there are three critical fans whose mechanical efficiency should be periodically reviewed to maintain constant cooling condition. These models are currently being applied for rod production control at the transformation at the conveyor of Tangshan Iron and Steel Co. Ltd., High Speed Wire Rod Rolling Mill, China. (author)

Feng, H.; Chu, J.; Li, K.; Liu, M. [Tangshan Iron and Steel Co. Ltd., High Speed Wire Rolling Mill, Tangshan, Hebei (China)

2000-07-01

348

Preparation and characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball milling  

Science.gov (United States)

High-energy ball milling is an effective method to produce nanocrystalline oxides. In this study, a conventional ZrO2-7%Y2O3 spray powder was ball-milled to produce nanocrystalline powders with high levels of crystalline disorders for deposition of thermal barrier coatings. The powder was milled both with 100Cr6 steel balls and with ZrO2-3%Y2O3 ceramic balls as grinding media. The milling time was varied in order to investigate the effect of the milling time on the crystallite size. The powders were investigated in terms of their crystallite sizes and morphologies by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that under given milling conditions the powder was already nanostructured after 40 min milling. The crystallite size decreased significantly with increasing milling time within first 120 min. After that, a further increase of milling time did not lead to a significant reduction of the crystallite size. Ball-milling led to lattice microstrains. Milling with the steel balls resulted in finer nano-sized crystal grains, but caused the contamination of the powder. The nano-sized crystal grains coarsened during the heat-treatment at 1250°C.

Bobzin, Kirsten; Zhao, Lidong; Schlaefer, Thomas; Warda, Thomas

2011-06-01

349

A Control Design for Grinding Systems with Feedforward Compensation  

Directory of Open Access Journals (Sweden)

Full Text Available The object of the present study is to design acontrol system for milling systems. An analyze of thedynamic behavior is described, aimed at designing acontrol system. The control system that is presenteduses PID control with feedforward compensation.

COSTEA Claudiu Raul

2012-01-01

350

"ONAR" ROLLS PRESERVE PREPARATION METHOD  

UK PubMed Central (United Kingdom)

FIELD: food production process. ^ SUBSTANCE: porcini mushrooms are sliced and blanched, garlic is blanched and minced, pork fat is minced the above-mentioned ingredients are mixed with culinary salt and hot black pepper for a homogenous farce formation. Pork is cut and beaten. The prepared farce is placed on the meat slices thus tenderised. The slices are rolled up and the rolls thus produced are fried in cooking fat. Potatoes are sliced, blanched and strained. Onions are cut and sautéed in margarine. Fresh green peas are frozen. Wheat flour is sautéed in margarine. The potatoes, onions, peas, wheat flour, milk, culinary salt and hot black pepper are mixed under oxygen-free conditions to produce the garnish. The rolls, garnish and mushroom broth are packaged, vacuum-sealed and sterilised. ^ EFFECT: diversification of available food products improved digestibility of preserve foods as compared to standard analogues (digestibility value increased from 2,1.105 to 2,5.105).

KVASENKOV OLEG IVANOVICH

351

"AMINAT" ROLL PRESERVE PREPARATION METHOD  

UK PubMed Central (United Kingdom)

FIELD: food production process. ^ SUBSTANCE: pre-processed cilantro is chopped and frozen, preferably - at a slow rate. Pre-processed brinsen cheese is grated. The above-mentioned ingredients are mixed with culinary salt, khmeli suneli spicy mixture and hot chili pepper under oxygen-free conditions for a homogenous farce formation. Pre-processed chicken fillet is beaten. The prepared farce is placed on the meat slices that are rolled up to produce rolls. Pre-processed cucumbers and tomatoes are sliced and blanched. Pre-processed lettuce is chopped and frozen, preferably - at a fast rate. The above-mentioned ingredients are mixed with culinary salt and calcium ascorbate under oxygen-free conditions to produce the garnish. The rolls, garnish and chicken broth are packaged, vacuum-sealed and sterilised which finally yields the target finished product. ^ EFFECT: pre-cooked food digestibility improvement.

KVASENKOV OLEG IVANOVICH

352

Robust Rudder Roll Damping Control  

DEFF Research Database (Denmark)

The results of a systematic research to solve a specific ship motion control problem, simultaneous roll damping and course keeping using the rudder are presented in this thesis. The fundamental knowledge a priori is that rudder roll damping is highly sensitive to the model uncertainty, therefore H-infinity theory is used to deal with the problem. The necessary mathematical tools and the H-Infinity theory as the basis of controller design are presented in Chapter 2 and 3. The mu synthesis and the D-K iteration are introduced in Chapter 3. The ship dynamics and modeling technology are discussed in Chapter 4, two kinds of ship model have been obtained: linear ship model used for designing the controller and nonlinear model used for simulation. The ship model uncertainty is discussed in this chapter and so is a wave model because the ship's roll motion is caused by waves. Using an unstructured model of uncertainty, three controllers with different kind of control schemes are designed by the mixed sensitivity method in Chapter 5. Sea-way simulation results show that each of these controllers have good robust stability and performance. The roll damping reduction is above 35% for all of these controllers. Roll reduction of near 70% has been obtained by the cascade controller. Using structured model of uncertainty, a m controller is designed in Chapter 6. The good robust performance has been recognized in the simulation results. It is shown that the m controller has the best robust characteristics with respect to model uncertainty and the roll reduction is near 50% with an envelope of model perturbations.

Yang, C.

1998-01-01

353

Modelling of the grinding process of SiC-aluminium composites  

Energy Technology Data Exchange (ETDEWEB)

In this paper some relationships for modelling forces, grinding energy and surface roughness in grinding of Metal Matrix Composites are proposed. To this purpose, experimental data obtained from tests carried out on a horizontal surface grinder have been employed. The simple relationships obtained could be utilized to predict how the cutting parameters influence the grinding process and the machining quality of these non-traditional materials.

Di Ilio, A.; Paoletti, A. [Universita di L`Aquila (Italy); Tagliaferri, V. [Universita di Genova (Italy)

1996-12-31

354

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

Energy Technology Data Exchange (ETDEWEB)

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.

Raj K. Rajamani

2006-07-21

355

Milling effect on preparing Ti-graphite based hydrogen storage material  

Energy Technology Data Exchange (ETDEWEB)

The ability of mechanical grinding of magnesium and graphite to enhance the hydrogen storage capacity of hydrogen storage containers was investigated. The storage container used in this work consisted of a titanium-based alloy and expandable graphite. Experiments were carried out at room temperature with pressure less than 50 atmospheres. Two scenarios were used to synthesize the alloy with the graphite, i.e. by ball milling and mechano-fusion. The mechano-fusion procedure proved to be superior in that there was no evidence of variation in alloy structure during this process, whereas the ball milling technique produced new active surfaces in the alloy, resulting in increased hydrogen absorption rates. Based on these preliminary results, it was concluded that the titanium-based alloy synthesized by mechano-fusion had a higher hydrogen storage capacity than material synthesized by the ball milling process. 8 refs., 8 figs.

Yen, P-S.; Hsiao, C-S.; Cheng, K-W.; Kuo, J-C. [Industrial Research Institute, Energy and Resources Laboratories, Hsinchu, Taiwan (China)

2004-07-01

356

Effect of the Vibration Parameters on the Ultra-Fine Particles Preparation in a Dry Roller Vibration Mill  

Science.gov (United States)

The motion equations of the filling layers are established to study the motion traces of the filler in the chamber of vibration mill. The research results indicate that the filler does the rotary motion relative to the body center on the suitable vibration intensity, in the region of the center forms a steady circle motion, but in other regions forms a cascade motion, which makes up for the lack of the energy in the chamber's center and edge. Afterward, under a specific parameters combination, the single crystalline, transparent, uniform, randomly oriented, almost equiaxed Zn nanostructures are obtained in the roller vibration mill grinded 11 h, in order to test the simulation experiment.

Xu, Bo; Wang, Shulin; Li, Laiqiang

2013-07-01

357

High efficiency and precision grinding of ceramics. ; Application of ELID-grinding. Ceramics no konoritsu/koseido kensaku. ; ELID kensakuho no tekiyo to jitsuyo  

Energy Technology Data Exchange (ETDEWEB)

For the electronic parts which have been establishing the modern high technology, the various hard and brittle materials are used. Although the high grade of parts and their efficient production technology are definitely needed, its final finishing relies on the polishing process, and therefore, the cost down and the automation are impeded. The author has succeeded the mirror surface grinding by the metal bonded grinding wheel, paying attention to the technology development which performs the mirror surface working only by the grinding. By this technology, the ceramics material well known as a hard material and so on, have become to be able to be made to the product only by grinding process with one rush, from the current process by which a long working time was required, and as a result of it, a possibility the working efficiency is elevated more than 10 times has come out. This new grinding technology has been begun to study also for the practical application at present, so that the application in the actual process is being started. In this paper, by the principle of the new grinding method with a high efficiency and high accuracy for the ceramics, the working device and working example, such as the electrolytic in-process dressing (ELID grinding method), the superiority and the practical application for it is introduced. 1 ref., 8 figs.

Omori, H. (Inst. of Physical and Chemical Reserch, Saitama (Japan))

1992-10-01

358

TL sensitivity of CaSO4:Dy phosphor powder - effect of grinding  

International Nuclear Information System (INIS)

Grinding of polycrystalline CaSO4:Dy phosphor to powder form induces lattice defects. Changes in thermoluminescence (TL) sensitivity due to variation in trap density in the bulk and on the surface of phosphor grains are studied using gamma and UV radiations. TL sensitivity to gamma increases with grinding time due to the contribution from the new bulk traps which are generated by grinding. The surface traps degrade with increase in grinding time resulting in a decrease in UV sensitivity. Results on regeneration of the TL sensitivity due to annealing at different temperatures are also included. (Auth.).

1979-01-01

359

Grinding and polishing tools for optical glasses; Kogaku glass ni okeru kensaku kenma toishi  

Energy Technology Data Exchange (ETDEWEB)

This paper describes development of grinding stones used for grinding and polishing optical glasses. Processing spherical lenses has used conventionally the lapping finish by using free abrasive grains, but has been changing into grinding using grinding stones to improve efficiency and reduce production cost. A problem in replacing the grinding material with a diamond fixed grain stone is dulling and loading. Adequate self-regenerative action of the grinding stone is necessary. Balance between processing force and retaining force in grain retaining and binding materials is important, whereas grinder manufacturers are trying contrivances in various ways. However, an external force (grinding force) may not be possible to be applied at a predetermined level if the self-regenerative action is to be optimized at work places for processing. Such know-hows are required as a supporting method to prevent lens deformation caused by the external force. In the polishing process, fine abrasive grains are used to increase the number of effective cutting edges in association with fixation of the abrasive grains. This may tend to cause loading in a grinding wheel and scratches on the processed surface due to aggregation of abrasive grains. In order to deal with this problem, an independently developed method is used to adjust binding force of binders, thus making grinding stones optimized for specific processing. 3 refs., 3 figs., 1 tab.

Kishida, T. [Olympus Optical Co. Ltd., Tokyo (Japan)

1997-04-01

360

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)

2009-01-01

 
 
 
 
361

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

Energy Technology Data Exchange (ETDEWEB)

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)

Neauport, J.; Cormont, P.; Destribats, J. [CESTA - CEA Centre d' Etudes Scientifiques et Techniques d' Aquitaine, 33 - Le Barp (France); Legros, P. [Univ Bordeaux 2, Plate Forme Imagerie Cellulaire Inst Neurosci, Inst Francois Magendie, F-33076 Bordeaux (France); Ambard, C. [CEA Centre d' Etudes du Ripault, 37 - Tours (France)

2009-03-15

362

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

UK PubMed Central (United Kingdom)

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.

Li C; Wang S; Zhang Q; Jia D

2013-06-01

363

Grinding tool for use in a fuel assembly repair and reconstitution system  

International Nuclear Information System (INIS)

[en] A remotely operable grinding apparatus particularly adapted for abrasively removing a portion of a structure underwater is described comprising a baseplate, a motor means having an output shaft, a grinding head operatively connected to the output shaft, a housing for isolating the motor means from ambient water, guide means slidably connecting the housing to the baseplate for guiding the grinding head to a selected portion of the structure, and means for selectively moving the grinding head against the portion of the structure

1988-01-01

364

Production method of seasoning laminaria roll  

UK PubMed Central (United Kingdom)

The invention relates to a production mthod of seasoning laminaria roll, which comprises the following steps that: dry laminaria roll is arranged inside clean water to be re-hydrated then the laminaria roll is put into baking soda solution to be soaked after being washed by clean water to be neutral, the laminaria roll is naturally drained the drained laminaria roll is put into a mixed sugar liquid consisting of maltitol solution and sorbose to be soaked seasoning material is added into the mixed sugar liquid to be uniformly mixed, and the laminaria roll is continuously soaked and the seasoning steeping liquid which steeps the laminaria roll is heated, heat-preserved, vacuum packed and sterilized in counter pressure. The seasoning laminaria roll which is produced with the method conforms to the taste of the public, has high nutrition value, is riched in minerals which are beneficial to the human body, and also enriches the types of the laminaria product.

RICHUN CHEN; XIUJUAN HUANG

365

Cell sorting by deterministic cell rolling†‡  

Science.gov (United States)

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.

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

2012-01-01

366

Cell sorting by deterministic cell rolling.  

UK PubMed Central (United Kingdom)

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.

Choi S; Karp JM; Karnik R

2012-04-01

367

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.

1996-01-01

368

Application of cryogenic grinding to achieve homogenization of transuranic wastes  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1996-08-01

369

Experimental and numerical investigations of hydroerosive grinding for injection components  

Energy Technology Data Exchange (ETDEWEB)

Diesel injection injectors are very complicated hydraulic systems which contain among other things small throttles and small sized blow holes in order to inject the fuel precisely into the combustion chamber. Due to the extremely strong exhaust laws, the geometrical forms and tolerances of the hydraulic components have to be maintained. The hydroerosive grinding process (HE process) is used for manufacturing of small holes using in Diesel injection components. A mixture of oil and small sized particles are used to form the final geometrical shapes of the throttles and the blow holes. Simulation models help to understand the underlying physical process and to optimize the manufacturing parameters for an efficient production process. This paper presents an Euler-Euler approach for the numerical simulation of the HE process. It describes a two-phase slurry flow consisting of a liquid and a dispersed solid phase which causes wear at walls of devices. The continuous fluid phase is solved using a finite volume scheme in which the Large Eddy Simulation (LES) model is applied to resolve large-scale turbulent structures. The solid phase is disperse and treated as a second continuum in which drag and lift forces as well as added mass, pressure and history force are taken into account. Considering particle-particle interactions, the granular model from Gidaspow is used for particle volume concentrations over 1%. Investigations of erosion processes proofed that non-spherically shaped particles as well as harder particles increase the wear on devices significantly. Consequently, non-spherical particles are utilized for the hydroerosive grinding. Their steady drag, unsteady drag and lift coefficients, depending on the particle Reynolds number, are determined by a direct numerical simulation via an in-house LES Lattice-Boltzmann solver. This Lattice-Boltzmann method was presented for laminar flows by Hoelzer. In this work, interpolating functions of these coefficients are implemented in the Euler-Euler approach which enable the simulation of non-spherical particle transports. Hydroerosive grinding experiments in three-dimensional planar geometries with an optical access are carried out to determine an erosion model depending on particle impact velocity, particle size, particle concentration and wall hardness. The implementation of a mesh-morphing algorithm combined with the Euler-Euler scheme of the commercial solver ANSYS CFX11 enables an online simulation of the hydroerosive grinding process. Additionally, the online simulation is used to validate the applied numerical methods. Very good agreements are achieved and will be presented in this paper. (orig.)

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

2011-07-01

370

Compound Taper Milling Machine.  

Science.gov (United States)

The report discusses some methods for the milling of tapered metal and plastic sections for use as honeycomb cores. These cores are intended for use in applications where loud bearing capacity and reduced weight are prime considerations.

1969-01-01

371

Rolling Tachyon in Nonlocal Cosmology  

CERN Document Server

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.

Joukovskaya, L

2007-01-01

372

Potential of rice mill`s cogeneration in Thailand  

Energy Technology Data Exchange (ETDEWEB)

In 1994 in Thailand, there were 312 rice mills of which 52 were par-boiled rice mills and 260 were white rice mills, each with a production capacity over 100 tons/day. These rice mills were taken into consideration for the potential of electricity generation within the mill using husk fuel. As rice mills used both electrical and thermal energy, there was the potential of cogeneration systems for rice mills. The objectives of this paper were to analyze the electrical and thermal energy consumption in white rice mills and par-boiled rice mills, and to present the application of cogeneration system for rice mills as well as the appropriate electricity price to be bought back by electricity producers. The operation of rice mills are described and the comparative cost of cogeneration systems is outlined. From the analysis of energy consumption of the equipment in white rice mills and par-boiled rice mills, it could be concluded that electricity consumption in white rice mills were 190 MJ/ton paddy and 242 Mj/ton paddy respectively. From the study it was found that average cost in reducing CO{sub 2} by forestation was 0.38 baht/kWh or 593 baht/ton CO{sub 2}. (author). 4 tabs., 3 figs., 3 refs.

Ekasilp, W.; Soponronnarit, S.; Therdyothin, A. [King Mongkut`s Inst. of Tech., Bangkok (Thailand)

1996-12-31

373

Ceramics cage mill; Ceramics cage mill  

Energy Technology Data Exchange (ETDEWEB)

A cage mill is a kind of impact crusher. This paper describes a structure and motion of the ceramics cage mill applying ceramics material, which is excellent in abrasion resistance, to impact pins. It also explains the improvement of abrasion resistance of ceramics. The cage mill uses two shafts standing opposite each other to rotate each rotor with impact pins arranged on a concentric circle in the opposite direction. The impact pins are arranged on concentric multi-rows, and it is designed that odd-numbered rows of pins and even-numbered rows of pins rotate in the opposite directions. Raw materials are supplied from the inner part of the inside row, and crushed matters are discharged from the outside row. When the ceramics sintered compact is impacted, particles are broken, or bonding between particles is broken, dropped off, and worn away. Therefore, abrasion resistance can be improved if ceramics are made to have fine structure by fining particles. The abrasion resistance of the ceramics is much better than that of high Cr cast iron and other metals unless impact energy exceeds its limit. 4 figs., 2 tabs.

Naito, S.

1994-12-27

374

Development of an O/W emulsion with high viscosity and fine droplet size in cold rolling of stainless steels; Konendo bisairyukeigata stainless yo reikanatsuenyu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

For a steel kind required to high surface gloss which is representative of stainless steel sheet, the development of rolling oil to make possible to obtain high surface gross even under the rolling condition of large diameter roller and to protect heat scratch formation in high speed rolling was conducted. When the production of rolling oil using tandem mills, it is necessary to reduce the amount of bring in oil under a condition of high speed rolling using large diameter roller. However, with the decrease of the amount of bring in oil, interfacial temperature on a roll bite increases, and heat scratch is apt to occur. In this study, a high viscosity and fine droplet size emulsion oil was proposed for the rolling oil fulfil these conflicting requirements. It is on a base of a concept to make to reduce the amount of bring in oil by the comminution of emulsion particle size and to secure the oil film strength in a wide range by the viscosity increase of base oil, and was confirmed the effectiveness in a laboratory experiment as well as in actual tandem mills machine. 15 refs., 8 figs., 4 tabs.

Kimura, Y.; Masuda, S.; Miyake, M. [NKK Corp., Yamaguchi (Japan). Materials and Processing Research Center; Yagi, R.; Mihara, Y. [NKK Corp., Tokyo (Japan); Yamakawa, M. [Nippon Quaker Chemical, Osaka (Japan)

1998-03-01

375

Transmission of toxic heavy metals to wheat grinding fractions  

Energy Technology Data Exchange (ETDEWEB)

In this examination, highly contaminated wheat which on account of a sewer slude fertilization showed high contents of cadmium (1 mg/kg), nickel (2,5 mg/kg) and zinc (75 mg/kg) was subjected to two different hulling procedures (laboratory pearler and pressing screw) to determine the reduction of the heavy metals. About 5-10% of the heavy metals cadmium and zinc could be removed by the hulling procedures with an abrasion of 4-6%, nickel was reduced by about 15%. The lead contamination could be removed by about 50%. The best reduction of the heavy metals was achieved by the grinding procedure. In the low-ash flours of the types 405 and 550, the contents of the heavy metals were reduced by more than 50%. In the flours of the types 812 and 1050 being higher on ash, the heavy metal contents were reduced by about 35-40% as compared to the initial product. In the high-ash low-grade flours, the heavy metal contents rose already to twice the concentration as to that in the initial wheat. In the bran fractions the heavy metal contents finally rise to two to five times the amount as in the initial wheat. The findings well conform to results from earlier investigations determined in normally contaminated wheat and wheat grinding fractions.

Brueggemann, J.; Ocker und Muehlening, H.D.; Zwingelberg, H.

1983-08-25

376

Dry-grinded ultrafine cements hydration. physicochemical and microstructural characterization  

Directory of Open Access Journals (Sweden)

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).

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

2013-01-01

377

Effects of imbalance and geometric error on precision grinding machines  

Energy Technology Data Exchange (ETDEWEB)

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.

Bibler, J.E.

1997-06-01

378

Electron spin resonance and thermoluminescence in powder form of clear fused quartz: effects of grinding  

Energy Technology Data Exchange (ETDEWEB)

Clear fused quartz (CFQ) tubes were powdered either manually by using a mortar and pestle (for coarse production) or mechanically, using a micronising mill (for fine production). A high and multisignal electron spin resonance (ESR) background was found in the fine powder even after annealing it at 900 deg. C for 20 min. In the case of the coarse powder, the signal (ESR background) varied inversely with particle size and was quite high for particle sizes lower than 38 {mu}m. In a subsidiary experiment, using fine SiO{sub 2} powder (99.8% pure, with the particle size of {approx}0.007 {mu}m), manufactured by using flame hydrolysis, only a weak background signal was found. The {sup 60}Co gamma-ray irradiated powders ({approx}22 Gy) were subjected to ESR analysis or thermoluminescence (TL) readout. The ESR intensity of the coarse powder varied directly with particle size. Thus, the intensity for a particle size of 20-38 {mu}m was very low and almost the same as the unirradiated intensity. In TL readout the results were the opposite: the TL intensity of the coarse powder varied inversely with the particle size down to 38 {mu}m, after which it decreased with decreasing particle size of the material. The fine powder, produced by grinding the CFQ tubes, was insensitive to gamma-rays (at least at doses of up to 50 Gy); but for the flame hydrolysis SiO{sub 2} the situation was the opposite. The minimum detectable dose (MDD) for the CFQ in powder form using ESR was {approx}2 Gy, which is {approx}2 times higher than that for the bulk form, while the MDD for the powder using TL was {approx}20 {mu}Gy, which is {approx}2 times lower than that for the bulk form of the material.

Ranjbar, A.H. [Physics Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Durrani, S.A. [School of Physics and Space Research, University of Birmingham, Birmingham (United Kingdom); Randle, K. [School of Chemistry, University of Birmingham, Birmingham (United Kingdom)

1999-02-01

379

Formation, physical stability and in vitro antimalarial activity of dihydroartemisinin nanosuspensions obtained by co-grinding method.  

Science.gov (United States)

The purpose of this study was to investigate the formation of drug nanoparticles from binary and ternary mixtures, consisting of dihydroartemisinin (DHA), a poorly water-soluble antimalarial drug, with water-soluble polymer and/or surfactant. Binary mixtures of drug/polyvinyl pyrrolidone K30 (PVP K30), binary mixtures of drug/sodium deoxycholate (NaDC), and ternary mixtures of drug/PVP K30/NaDC were prepared at different weight ratios and then ground by vibrating rod mill to obtain ground mixtures. Nanosuspension was successfully formed after dispersing ternary ground mixtures or DHA/NaDC ground mixtures in water. The ternary ground mixtures did not give superior nanosuspension in terms of particle size reduction and recovery of drug nanoparticles, but they provided more physically stable nanosuspensions than DHA/NaDC ground mixtures. The size of drug nanoparticles was decreased with increasing grinding time and lowering amount of PVP K30 and NaDC. About 95% of drug nanoparticles were found in the nanosuspension from ternary ground mixtures. Zeta potential measurement suggested that stable nanosuspension was attributable to adsorption of NaDC and PVP K30 onto surface of drug particles. Atomic force microscopy and transmission electron microscopy with selected area diffraction indicated that DHA in nanosuspension was existed as nanocrystals. The obtained nanosuspensions had higher in vitro antimalarial acitivity against Plasmodium falciparum than microsuspensions. The results suggest that co-grinding of DHA with PVP K30 and NaDC seems to be a promising method to prepare DHA nanosuspension. PMID:18363147

Chingunpitak, Jiraporn; Puttipipatkhachorn, Satit; Chavalitshewinkoon-Petmitr, Porntip; Tozuka, Yuichi; Moribe, Kunikazu; Yamamoto, Keiji

2008-03-01

380

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

Energy Technology Data Exchange (ETDEWEB)

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 {mu}m) by measuring the particle Ferret's diameter through scanning electron microscopy, while for the smallest one (<3 {mu}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 {mu}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.

Martena, Valentina; Censi, Roberta [University of Camerino, School of Pharmacy (Italy); Hoti, Ela; Malaj, Ledjan [University of Tirana, Department of Pharmacy (Albania); Martino, Piera Di, E-mail: piera.dimartino@unicam.it [University of Camerino, School of Pharmacy (Italy)

2013-06-15

 
 
 
 
381

Device for covering roofing with rolled material  

Energy Technology Data Exchange (ETDEWEB)

The device for covering roof with rolled material installed on a tunneling combine includes a frame, stand, drum with rolled material installed on the axis, cantilevers and attachment for pressing the drum with the rolled material to the roofing. In order to increase the output of the device by expanding the range of width of the rolled material depending on the width of coverage and the design of the working mechanism of the combine, the frame is made with a through longitudinal slit and the length can be adjusted by axial movement to accommodate longer rolls of material.

Rubis, V.K.; Borovikov, A.Ye.; Kemerov, V.A.; Sarin, P.G.

1981-01-01

382

Almost rolling motion: An investigation of rolling grooved cylinders  

CERN Document Server

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.

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

1998-01-01

383

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

1980-05-29

384

Rubber rolling over a sphere  

Science.gov (United States)

“Rubber” coated bodies rolling over a surface satisfy a no-twist condition in addition to the no slip condition satisfied by “marble” coated bodies [1]. Rubber rolling has an interesting differential geometric appeal because the geodesic curvatures of the curves on the surfaces at 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 exceptional group G 2). The 2 3 5 nonholonomic geometries are classified in a companion paper [2] via Cartan’s equivalence method [3]. Rubber rolling of a convex body over a sphere defines a generalized Chaplygin system [4 8] with SO(3) symmetry group, total space Q = SO(3) × S 2 and base S 2, that can be reduced to an almost Hamiltonian system in T* S 2 with a non-closed 2-form ?NH. In this paper we present some basic results on the sphere-sphere problem: a dynamically asymmetric but balanced sphere of radius b (unequal moments of inertia I j but with center of gravity at the geometric center), rubber rolling over another sphere of radius a. In this example ?NH is conformally symplectic [9]: the reduced system becomes Hamiltonian after a coordinate dependent change of time. In particular there is an invariant measure, whose density is the determinant of the reduced Legendre transform, to the power p = 1/2( b/a - 1). Using sphero-conical coordinates we verify the result by Borisov and Mamaev [10] that the system is integrable for p = -1/2 (ball over a plane). They have found another integrable case [11] corresponding to p = -3/2 (rolling ball with twice the radius of a fixed internal ball). Strikingly, a different set of sphero-conical coordinates separates the Hamiltonian in this case. No other integrable cases with different I j are known.

Koiller, J.; Ehlers, K.

2007-04-01

385

Effect of the milling conditions on the degree of amorphization of selenium by milling in a planetary ball mill  

International Nuclear Information System (INIS)

The effect of the milling parameters (rotation speed of the milling device and duration of milling) on the phase composition of the products of milling of fully crystalline selenium has been investigated. The milling was conducted using a planetary micromill and the phase composition of the milling products was determined by differential thermal analysis. It has been found that ball milling leads to the partial amorphization of the starting crystalline material. The content of amorphous phase in the milling products depends, in a rather complicated way, on the milling parameters. At the milling parameters adopted in the present study, the milling product was never fully amorphous. The complicated way the milling parameters affect the content of amorphous phase in the milling products is a result of competition of two processes: amorphization due to deformation and refinement of grains of milled material and crystallization of the already produced amorphous material at the cost of heat evolved in the milling vial during the milling process.

2007-01-01

386

[Study on grinding of base metal alloys. 5. Constant pressure grinding of a Ni-Cr alloy with electro-deposited wheels  

UK PubMed Central (United Kingdom)

The grinding techniques and electro-deposited wheels suitable for a 13% Cr-Ni dental casting alloy were determined. The lever-type grinding test machine modified in the previous study was used to investigate the grinding performance of experimental wheels of CBN- and diamond-particles. Depression of the diamond wheel against the work yielded unfavorable grinding results. Not only depression of the wheel against it but also moving the wheel over it with a heavier pressure is desired for higher grinding efficiency and its durability. Probably, the undurability of this wheel is associated with abrasive attrition due to oxidation or some chemical reaction with the work. The CBN wheel had not been suitable for the Co-Cr alloy tested in the third paper, but it exhibited very excellent performance for grinding of the Ni-Cr alloy, even without being moved over the work. Although being high in cost, the CBN wheel may pay for the very high performance and its durability.

Miyakawa O; Watanabe K; Okawa S; Nakano S; Shiokawa N; Kobayashi M; Tamura H

1989-09-01

387

Dual string packer mill  

Energy Technology Data Exchange (ETDEWEB)

A packer mill is described comprising: an annular sleeve; means on the lower end of the sleeve for milling the periphery of a packer; an axial mandrel inside the sleeve; means on the lower end of the mandrel for milling an axial hole into the upper end of a packer at an elevation above the milling of the periphery of the packer; an axial slidable gripper sleeve on the mandrel including longitudinally extending fingers. Each of the fingers comprises outwardly facing serrations for gripping the walls of the hole in the packer; a camming sleeve on the mandrel inside the gripper sleeve for camming the fingers radially outwardly for engaging the walls of the axial hole milled in the packer for supporting the packer; a release ring around the mandrel engaging an end of the camming sleeve; and means for bursting the ring in hoop tension upon application of sufficient axial force between the mandrel and camming sleeve for releasing the camming sleeve for axially sliding away from the gripper sleeve for permitting the fingers to collapse radially inwardly.

Desai, P.C.

1987-09-29

388

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)

Full Text Available Abstract in spanish 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 anális (more) is 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 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. Res (more) ults 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.

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

2013-01-01

389

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)

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.

Adriana M Osorio; Juan M Marín; Gloria Restrepo

2013-01-01

390

Finite element analysis of roll bit behaviors in cold foil rolling process  

Science.gov (United States)

To investigate roll bite behaviors in cold foil rolling process, a 2D elasto-plastic finite model is established using FEM software ABAQUS. Contact pressure distribution and roll contour in roll bite are also presented, which demonstrate that foil rolling process is different from conventional strip rolling process. The contact area is composed of entry elastic zone, entry plastic zone, an extensive neutral zone, exit plastic zone and exit elastic zone. It conforms to the results of Fleck foil rolling theory. Elastic deformation and work hardening of foil in roll bite are taken into account. The effect of rolling parameters, such as friction coefficient, entry thickness and reduction rate on distribution of contact pressure and vertical displacement are also discussed.

Hao, Liang; Jiang, Zhengyi; Wei, Dongbin; Chen, Xiawei

2013-05-01

391

Increased roll stability suspension system  

Energy Technology Data Exchange (ETDEWEB)

A suspension system is described for suspending an elongated chassis of a vehicle, such as a heavy duty truck, above the front axle and rear axle of a transversely extending tandem axle combination. The suspension system comprises: means for locating the roll center of the vehicle at an elevation below the elevation of the axles; and a stabilizer unit for providing roll stability to the vehicle. The stabilizer unit is mounted to the vehicle chassis at a pivot point longitudinally intermediate the front axle and the rear axle of the tandem axle combination for rotation in a generally horizontal plane. The stabilizer unit includes a pair of linkage members, each linkage member extending generally longitudinally outward from the pivot point in a direction opposite from the other linkage member and toward a corresponding axle.

Giese, L.

1987-05-26

392

Rolling tachyons and decaying branes  

International Nuclear Information System (INIS)

[en] We present new rolling tachyon solutions describing the classical decay of D-branes. Our methods are simpler than those appearing in recent works, yet our results are exact in classical string theory. The role of pressure in the decay is studied using tachyon profiles with spatial variation. In this case the final state involves an array of codimension one D-branes rather than static, pressureless tachyon matter. (author)

2003-01-01

393

FINE GRINDING AND AIR CLASSIFICATION OF FIELD PEA  

Science.gov (United States)

Field pea has about 23% protein and 48% starch. Pin milling at 1 x 14,000, 3 x 14,000, 9 x 14,000 and 12 x 14,000 rpm followed by air classification according to particle size resulted in fine fractions (18 µm) with high starch content. ...

394

Effect of ball size distribution on milling rate  

Energy Technology Data Exchange (ETDEWEB)

This paper focuses on the determination of the selection function parameters {alpha}, a, {mu} and {Lambda} together with the exponent factors {eta} and {xi} describing the effect of ball size on milling rate for a South African coal. A series of batch grinding tests were carried out using three media single sizes, i.e. 30.6, 38.8, and 49.2 mm. Then two ball mixtures were successively considered. The original manufacturer's recommended ball mixture was used to investigate the effect of ball size distribution on the selection function whereas the equilibrium ball mixture was used to validate the model. Results show that with the six parameters abovementioned, the charge mixture is fully characterized with about 5% deviation. Interestingly, the estimated parameters can be used in the simulator model allowing one to find the optimal ball charge distribution for a set of operational constraints.

Katubilwa, F.M.; Moys, M.H. [University of Witwatersrand, Johannesburg (South Africa)

2009-12-15

395

Rolling Contact Fatigue of Ceramics  

Energy Technology Data Exchange (ETDEWEB)

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.

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

396

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

Science.gov (United States)

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

Zügner, Sascha; Marquardt, Karin; Zimmermann, Ingfried

2005-10-03

397

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

UK PubMed Central (United Kingdom)

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.

Zügner S; Marquardt K; Zimmermann I

2006-02-01

398

Pyrolysis of a waste from the grinding of scrap tyres.  

UK PubMed Central (United Kingdom)

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

Fernández AM; Barriocanal C; Alvarez R

2012-02-01

399

Economic evaluation of cryogenic-grinding of scrap automotive tyres  

Energy Technology Data Exchange (ETDEWEB)

A discounted cash flow appraisal of a cryogenic-grinding (C-G) plant suitable for recycling scrap steel-radial automobile tyres is performed. The results of this appraisal are analysed using a sensitivity analysis to identify the critical variables and their break-even values for making the plant profitable. It is concluded that the C-G plant not only faces the problem of whether the initially assumed values for selling price, variable cost and volume could be achieved in the light of the structure of the rubber recycling industry but also whether the values could be achieved for sufficiently long periods for the plant to survive and become profitable. (U.K.).

Harrison, K.; Tong, S.G.; Hilyard, N.C.

1986-01-01

400

Pyrolysis of a waste from the grinding of scrap tyres.  

Science.gov (United States)

The fibres that are used to reinforce tyres can be recovered as a waste in the process of grinding of scrap tyres. In this paper beneficiation through pyrolysis is studied since the fibres are made up of polymers with a small amount of rubber because the latter is difficult to separate. The experiments were performed at three temperatures (400, 550 and 900°C) in a horizontal oven. The three products - gas, oil and char - obtained from the pyrolysis were investigated. The composition of the gas was analyzed by means of gas chromatography. The oil was studied by gas chromatography and infrared spectroscopy. The char porous structure was determined by N(2) adsorption. In addition, the topography of the chars was studied by means of scanning electron microscopy (SEM). The products resulting from the pyrolysis of the fibres were compared with those obtained from scrap rubber. PMID:22204837

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

2011-12-13

 
 
 
 
401

Rolling tooth-like axle harrow  

UK PubMed Central (United Kingdom)

The utility model discloses a rolling tooth-like axle harrow, particularly the technical field of ordinary agricultural machinery. The aim of the utility model is to provide a new harrow for agriculture in order to solve the existing problems of the prior art. The principles of scrolling, rolling and thrust work are used, and steel pipes or the angle iron is connected to form a rectangular frame. An iron roller with a plurality of thorns is arranged in the frame, the iron roller is parallel with two long sides of a rectangle, and both ends are connected with two short sides with the rolling method. The middle parts of the two long sides are provided with traction frames to form the rolling tooth-like axle harrow. More specifically, the rolling tooth-like axle harrow is composed of a tooth-like axle harrow frame, the traction frames and a rolling tooth-like axle, wherein the rolling tooth-like axle comprises the iron roller, rolling thorns and a rolling axle, and the rolling tooth-like axle is arranged in the tooth-like axle harrow frame. The rolling thorns are arranged on the outer surface of a cylinder of the iron roller, the rolling axle is arranged on both ends of the iron roller, and the rolling axle is connected with a left and a right harrow tips through flanges and connecting screws. The utility model is used for leveling soil and preserving the soil moisture of broken soil for agriculture and relevant industries.

WEI HUAWU

402

System for manufacturing wooden rotor blades for small wind mills  

Energy Technology Data Exchange (ETDEWEB)

Acknowledging the need (also in developing countries) for small windmill wings with various patterns and aerodynamic characteristics a simple, low-cost hand-controlled copying milling machine was built (with standard parts) to reduce production time for one wing to 1-2 hours. A sensor-roll transfers the airfoil pattern to a set of two saw blades, driven by an electric motor, which carves the airfoil out of a wooden beam. It is thus possible to cut out each cross section of the wing and manufacture a constantly reproducible rotor blade. The hard-foam airfoil models - th