WorldWideScience

Sample records for grinding wheel load

  1. Grinding Wheel System

    Science.gov (United States)

    Malkin, Stephen; Gao, Robert; Guo, Changsheng; Varghese, Biju; Pathare, Sumukh

    2003-08-05

    A grinding wheel system includes a grinding wheel with at least one embedded sensor. The system also includes an adapter disk containing electronics that process signals produced by each embedded sensor and that transmits sensor information to a data processing platform for further processing of the transmitted information.

  2. Grinding Wheel Profile

    Science.gov (United States)

    2004-01-01

    This graphic dubbed by engineers as the 'Grinding Wheel Profile' is the detective's tool used by the Opportunity team to help them understand one of the processes that formed the interior of a rock called 'McKittrick.' Scientists are looking for clues as to how layers, grains and minerals helped create this rock, and the engineers who built the rock abrasion tool (RAT) wanted to ensure that their instrument's handiwork did not get confused with natural processes.In the original microscopic image underlaying the graphics, engineers and scientists noticed 'layers' or 'scratches' on the spherical object nicknamed 'blueberry' in the lower right part of the image. The designers of the rock abrasion tool noticed that the arc length and width of the scratches were similar to the shape and size of the rock abrasion tool's grinding wheel, which is made out of a pad of diamond teeth.The scrapes on the bottom right blueberry appear to be caused by the fact that the berry got dislodged slightly and its surface was scraped with the grinding pad. In this image, the largest yellow circle is the overall diameter of the hole ground by the rock abrasion tool and the largest yellow rectangular shape is the area of the grinding wheel bit. The smaller yellow semi-circle is the path that the center of the grinding tool follows. The orange arrow arcing around the solid yellow circle (center of grinding tool) indicates the direction that the grinding tool spins around its own center at 3,000 revolutions per minute. The tool simultaneously spins in an orbit around the center of the hole, indicated by the larger orange arrow to the left.The grinding tool is 22 millimeters (0.9 inches) in length and the actual grinding surface, which consists of the diamond pad, is 1.5 millimeters (0.06 inches) in length, indicated by the two smaller rectangles. You can see that the smaller bottom rectangle fits exactly the width of the scrape marks.The grooves on the blueberry are also the same as the

  3. Grinding Characteristics Of Directionally Aligned SiC Whisker Wheel-Comparison With Al2O3 Fiber Wheel

    Institute of Scientific and Technical Information of China (English)

    魏源迁; 山口胜美; 菊泽贤二; 洞口严; 中根正喜

    2003-01-01

    A unique SiC whisker wheel was invented,in which the whiskers were aligned normally to the grinding wheel surface.In this paper,grindabilities of the SiC whisker wheel are investigated and compared with those of other wheels of SiC grains,Al2O3 grains,as well as Al2O3 long and short fibres which were also aligned normally to the grinding wheel surface,respectively.The main research contents concern grinding characteristics of a directionally aligned SiC whisker wheel such as material-removal volume,wheel-wear rates,integrity of the ground surfaces,grinding ratios and grinding efficiency.Furthermore,grinding wheels of whiskers and fibres have a common disadvantage:they tend to load easily.The authors have proposed a simple method of loading-free grinding to overcome this propensity and investigate some related grinding characteristics under loading-free grinding conditions.

  4. The Study on Grinding Ratio in Form Grinding with White Fused Alumina (WA) Grinding Wheels

    Science.gov (United States)

    Junming, Wang; Jiong, Wang; Deyuan, Lou

    2018-03-01

    The study is carried out based on an experiment of form grinding spur rack with white fused alumina (WA) grinding wheels. In the experiment, SOV-3020A type tri-axial image mapper is utilized to measure the profile of the tooth space in the rack, and the curve equations between the sectional area of the tooth space and the tooth sequence under different grinding depths are established by nonlinear curve regress using software of origin8.0. Then, it deduces the prediction equations for current grinding ratio and cumulative grinding ratio under different grinding depths. The result shows that the grinding ratio is exponential decline relationship with the increase of the number of the tooth to be ground under the same grinding depth, and the decline speed is fast in the initial stage. With the increase of grinding depth, the grinding ratio increases gradually. The cumulative grinding ratio is about twice as high as the current grinding ratio. Thus, large grinding depth is generally used in rough grinding to improve grinding efficiency.

  5. The Influence of Wet Dressing of Grinding Wheel on the Grinding Performance

    OpenAIRE

    重松, 日出見; 冨田, 進

    1989-01-01

    Experiments on the relation between the form of working plane of grinding wheel which was formed by dressing, and the grinding performance of working plane of grinding wheel in the early stage of grinding, were carried out supplying the same grinding fluid in dressing time and grinding time. As a result, it was found that the difference of the action or the effect of grinding fluids on the working plane of grinding fluid were related to the grinding performance in the early stage of grinding....

  6. Performance Evaluation of Abrasive Grinding Wheel Formulated ...

    African Journals Online (AJOL)

    This paper presents a study on the formulation and manufacture of abrasive grinding wheel using locally formulated silicon carbide abrasive grains. Six local raw material substitutes were identified through pilot study and with the initial mix of the identified materials, a systematic search for an optimal formulation of silicon ...

  7. The Effects of Wear upon the Axial Profile of a Grinding Wheel in the Construction of Innovative Grinding Wheels for Internal Cylindrical Grinding

    OpenAIRE

    Nadolny, K.; Słowiński, B.

    2011-01-01

    The article describes the effects of wear upon the axial profile of a grinding wheel in the axial cylindrical grinding processes. This mechanism was used to develop a grinding wheel with zone diversified structure made of microcrystalline sintered corundum abrasive grains and vitrifies bond. Such a grinding wheel is characterized by the conical rough grinding zone that is made by grains of a relatively large size, and a cylindrical finish grinding zone with grains of a smaller size and can be...

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

    Directory of Open Access Journals (Sweden)

    M. A. Shavva

    2014-01-01

    for chips is formed between diamond grains. This allows the grinding wheel to avoid loading.The stand solves the problem of electrolyte purification. This helps to avoid burn marks and defects during grinding. A maximum efficiency of process may be achieved by adjusting the modes of wheel dressing.The ECD allows the use of nontraditional methods of grinding, including ductile mode grinding. However, for this it is necessary to apply the special kinematic scheme of grinding.

  9. Development of Composite Grinding Wheels for Hard and Soft Metals

    OpenAIRE

    Pruti, Faruk

    2012-01-01

    This research investigates the performance of grinding wheel in terms of its internal granular particles and their effect on the surface finish for both soft and hard metals subjected to both dry and wet conditions of use. The study considers the properties of materials of construction including hardness of the granular particles and their size and distributions that affects the grinding wheel efficiency in abrading of soft and hard metal surfaces. Furthermore, in order to improve grinding pe...

  10. Investigation of diamond wheel topography in Elliptical Ultrasonic Assisted Grinding (EUAG) of monocrystal sapphire using fractal analysis method.

    Science.gov (United States)

    Wang, Qiuyan; Zhao, Wenxiang; Liang, Zhiqiang; Wang, Xibin; Zhou, Tianfeng; Wu, Yongbo; Jiao, Li

    2018-03-01

    The wear behaviors of grinding wheel have significant influence on the work-surface topography. However, a comprehensive and quantitative method is lacking for evaluating the wear conditions of grinding wheel. In this paper, a fractal analysis method is used to investigate the wear behavior of resin-bonded diamond wheel in Elliptical Ultrasonic Assisted Grinding (EUAG) of monocrystal sapphire, and a series of experiments on EUAG and conventional grinding (CG) are performed. The results show that the fractal dimension of grinding wheel topography is highly correlated to the wear behavior, i.e., grain fracture, grain pullout, and wheel loading. An increase in cutting edge density on the wheel surface results in an increase of the fractal dimension, but an increase in the grain pullout and wheel loading results in a decrease in the fractal dimension. The wheel topography in EUAG has a higher fractal dimension than that in CG before 60 passes due to better self-sharpening behavior, and then has a smaller fractal dimension because of more serious wheel loadings after 60 passes. By angle-dependent distribution analysis of profile fractal dimensions, the wheel surface topography is transformed from isotropic to anisotropic. These indicated that the fractal analysis method could be further used in monitoring of a grinding wheel performance in EUAG. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Technics study on high accuracy crush dressing and sharpening of diamond grinding wheel

    Science.gov (United States)

    Jia, Yunhai; Lu, Xuejun; Li, Jiangang; Zhu, Lixin; Song, Yingjie

    2011-05-01

    Mechanical grinding of artificial diamond grinding wheel was traditional wheel dressing process. The rotate speed and infeed depth of tool wheel were main technics parameters. The suitable technics parameters of metals-bonded diamond grinding wheel and resin-bonded diamond grinding wheel high accuracy crush dressing were obtained by a mount of experiment in super-hard material wheel dressing grind machine and by analysis of grinding force. In the same time, the effect of machine sharpening and sprinkle granule sharpening was contrasted. These analyses and lots of experiments had extent instruction significance to artificial diamond grinding wheel accuracy crush dressing.

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

    Directory of Open Access Journals (Sweden)

    Chen Zhenzhen

    2014-08-01

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

  13. System Analysis of Flat Grinding Process with Wheel Face

    Directory of Open Access Journals (Sweden)

    T. N. Ivanova

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-05-01

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

  15. 30 CFR 56.15014 - Eye protection when operating grinding wheels.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Eye protection when operating grinding wheels... MINES Personal Protection § 56.15014 Eye protection when operating grinding wheels. Face shields or goggles in good condition shall be worn when operating a grinding wheel. [53 FR 32526, Aug. 25, 1988] ...

  16. 30 CFR 57.15014 - Eye protection when operating grinding wheels.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Eye protection when operating grinding wheels. 57.15014 Section 57.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... grinding wheels. Face shields or goggles in good condition shall be worn when operating a grinding wheel...

  17. The effect of wheel eccentricity and run-out on grinding forces, waviness, wheel wear and chatter

    OpenAIRE

    O'DONNELL, GARRET; MURPHY, STUART

    2011-01-01

    PUBLISHED The effect of grinding-wheel eccentricity on grinding forces, wheel wear and final waviness height was studied. Eccentricity was evident in force oscillations and acceleration and audio measurements. A model was developed to predict final scallop-profile shape from grinding parameters and eccentricity. Recommendations are given on detecting eccentricity and determining when eccentricity is tolerable.

  18. Mechanical Properties of Oxide Films on Electrolytic In-process Dressing (ELID) Copper-based Grinding Wheel

    Science.gov (United States)

    Kuai, J. C.; Wang, J. W.; Jiang, C. R.; Zhang, H. L.; Yang, Z. B.

    2018-05-01

    The mechanical properties of oxide films on copper based grinding wheel were studied by nanoindentation technique. The analysis of load displacement shows that the creep phenomenon occurs during the loading stage. Results show that the oxide film and the matrix have different characteristics, and the rigidity of the copper based grinding wheel is 0.6-1.3mN/nm, which is weaker than that of the matrix; the hardness of the oxide film is 2000-2300MPa, which is higher than the matrix; and the elastic modulus of the oxide film is 100-120GPa, also higher than the matrix.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-02-01

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

  20. Numerical Simulation of a Grinding Process for the Spatial Work-pieces: a Model of the Workpiece and Grinding Wheel

    Directory of Open Access Journals (Sweden)

    I. A. Kiselev

    2015-01-01

    Full Text Available The paper describes a spatial grinding dynamics mathematical model. This model includes a grinding wheel dynamics model, a work-piece dynamics model, and a numerical algorithm of geometric modeling as well. The geometric modeling algorithm is based on the Z-buffer method with author’s modifications. This algorithm allows us to simulate the formation of a new workpiece surface when removing material and as well as to determine the cutting layer thickness for each abrasive grain of the grinding wheel. The use of the surface cell bilinear approximation and the simultaneous use of multiple projection directions are the special features of the algorithm. These features improve modeling quality of machined surface. The grinding wheel model is represented as cutting micro-edges (grains set. Abrasive grains are randomly distributed on the wheel outer surface. Grains size, shape, wheel structure and graininess are taken into account. To determine the uncut chip thickness, which is cut off by each grain of the grinding wheel is used the algorithm, which finds intersection point of uncut work-piece surface with radial ray passing through the grain cutting edge. Grinding forces for each grain are defined based on the cutting layer thickness value using the phenomenological models described in the literature. Using transformations described in the article, grinding forces determined for each grain are reduced to the total grinding force, which acts on the tool and machined work-piece in the appropriate coordinate systems. Work-piece dynamics is modeled with the help of the finite element method using quadratic tetrahedral elements. The described model of spatial grinding dynamics makes it possible to evaluate the level of vibration and grinding forces, as well as the shape errors and surface quality of machined work-piece.

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

    Directory of Open Access Journals (Sweden)

    Shi Chaofeng

    2014-04-01

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

  2. Exploration on Wire Discharge Machining Added Powder for Metal-Based Diamond Grinding Wheel on Wire EDM Dressing and Truing of Grinding Tungsten Carbide Material

    Science.gov (United States)

    Chow, H. M.; Yang, L. D.; Lin, Y. C.; Lin, C. L.

    2017-12-01

    In this paper, the effects of material removal rate and abrasive grain protrusion on the metal-based diamond grinding wheel were studied to find the optimal parameters for adding powder and wire discharge. In addition, this kind of electric discharge method to add powder on the metal-based diamond grinding wheel on line after dressing and truing will be applied on tungsten carbide to study the grinding material removal rate, grinding wheel wear, surface roughness, and surface micro-hardness.

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  4. Effects of hardness of abrasive grains on surface roughness of work piece in PVA bonded grinding wheel

    International Nuclear Information System (INIS)

    Nitta, S.; Takata, A.; Ishizaki, K.

    2000-01-01

    The purpose of this study is to clarify relation between hardness of abrasive grains and surface roughness of work piece in the case of PVA (Polyvinyl alcohol) bonded grinding wheels. Two PVA bonded grinding wheels; with diamond or silicon carbide as abrasive grains and grinding of glass and aluminum alloy was performed. The PVA bonded grinding wheels The PVA bonded grinding wheel with silicon carbide could not grind the glass. Because insufficiency in hardness, the PVA bonded grinding wheel with the diamond abrasive grains caused deep scratch on the aluminum alloy. It was found that the final surface roughness of the work piece was not proportional to the hardness of abrasive grains. The suitable hardness of abrasive grains will be obtained by the hardness of work piece. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  5. A method of detection to the grinding wheel layer thickness based on computer vision

    Science.gov (United States)

    Ji, Yuchen; Fu, Luhua; Yang, Dujuan; Wang, Lei; Liu, Changjie; Wang, Zhong

    2018-01-01

    This paper proposed a method of detection to the grinding wheel layer thickness based on computer vision. A camera is used to capture images of grinding wheel layer on the whole circle. Forward lighting and back lighting are used to enables a clear image to be acquired. Image processing is then executed on the images captured, which consists of image preprocessing, binarization and subpixel subdivision. The aim of binarization is to help the location of a chord and the corresponding ring width. After subpixel subdivision, the thickness of the grinding layer can be calculated finally. Compared with methods usually used to detect grinding wheel wear, method in this paper can directly and quickly get the information of thickness. Also, the eccentric error and the error of pixel equivalent are discussed in this paper.

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

    Directory of Open Access Journals (Sweden)

    M. A. Shavva

    2014-01-01

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

  7. Virtual sensors for on-line wheel wear and part roughness measurement in the grinding process.

    Science.gov (United States)

    Arriandiaga, Ander; Portillo, Eva; Sánchez, Jose A; Cabanes, Itziar; Pombo, Iñigo

    2014-05-19

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

  8. Temperature measurement of flat glass edge during grinding and effect of wheel and workpiece speeds

    International Nuclear Information System (INIS)

    Moussa, Tala; Garnier, Bertrand; Peerhossaini, Hassan

    2017-01-01

    Flat glass temperature at the vicinity of the grinding wheel during grinding can become very high and reach that of the glass transition (typically around 550–600 °C). In such cases, the mechanical strength of glass is greatly affected and the grinding process cannot be carried out properly. Hence, thermal phenomena must be managed by adjusting the machining parameters to avoid overheating. For this purpose, it is very important to be able to measure the glass temperature, especially at the grinding interface. However, measuring the interfacial glass temperature is difficult and none of the existing methods for metal grinding is adequate for glass grinding. This work shows a novel temperature method that uses constantan and copper strips on both sides of the glass plates; thermoelectric contact being provided by the metallic binder of diamond particles in the grinding wheel. This new technique allows the measurement of the glass edge temperature during the wheel displacement around the glass plate. The experimental results show an average glass edge temperature between 300 and 600 °C depending on the value of the machining parameters such as work speed, wheel speed, depth of cut and water coolant flow rate. As this new thermal instrumentation is rather intrusive, glass temperature biases were analysed using a 3D heat transfer model with a moving source. Model computations performed using finite elements show that the temperature biases are less than 70 °C, which is smaller than the standard deviation of the glass edge temperatures measured during grinding. (paper)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

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

  10. Genetic Algorithm-Based Optimization for Surface Roughness in Cylindrically Grinding Process Using Helically Grooved Wheels

    Science.gov (United States)

    Çaydaş, Ulaş; Çelik, Mahmut

    The present work is focused on the optimization of process parameters in cylindrical surface grinding of AISI 1050 steel with grooved wheels. Response surface methodology (RSM) and genetic algorithm (GA) techniques were merged to optimize the input variable parameters of grinding. The revolution speed of workpiece, depth of cut and number of grooves on the wheel were changed to explore their experimental effects on the surface roughness of machined bars. The mathematical models were established between the input parameters and response by using RSM. Then, the developed RSM model was used as objective functions on GA to optimize the process parameters.

  11. Customer loads of two-wheeled vehicles

    Science.gov (United States)

    Gorges, C.; Öztürk, K.; Liebich, R.

    2017-12-01

    Customer usage profiles are the most unknown influences in vehicle design targets and they play an important role in durability analysis. This publication presents a customer load acquisition system for two-wheeled vehicles that utilises the vehicle's onboard signals. A road slope estimator was developed to reveal the unknown slope resistance force with the help of a linear Kalman filter. Furthermore, an automated mass estimator was developed to consider the correct vehicle loading. The mass estimation is performed by an extended Kalman filter. Finally, a model-based wheel force calculation was derived, which is based on the superposition of forces calculated from measured onboard signals. The calculated wheel forces were validated by measurements with wheel-load transducers through the comparison of rainflow matrices. The calculated wheel forces correspond with the measured wheel forces in terms of both quality and quantity. The proposed methods can be used to gather field data for improved vehicle design loads.

  12. Developing a trend prediction model of subsurface damage for fixed-abrasive grinding of optics by cup wheels.

    Science.gov (United States)

    Dong, Zhichao; Cheng, Haobo

    2016-11-10

    Fixed-abrasive grinding by cup wheels plays an important role in the production of precision optics. During cup wheel grinding, we strive for a large removal rate while maintaining fine integrity on the surface and subsurface layers (academically recognized as surface roughness and subsurface damage, respectively). This study develops a theoretical model used to predict the trend of subsurface damage of optics (with respect to various grinding parameters) in fixed-abrasive grinding by cup wheels. It is derived from the maximum undeformed chip thickness model, and it successfully correlates the pivotal parameters of cup wheel grinding with the subsurface damage depth. The efficiency of this model is then demonstrated by a set of experiments performed on a cup wheel grinding machine. In these experiments, the characteristics of subsurface damage are inspected by a wedge-polishing plus microscopic inspection method, revealing that the subsurface damage induced in cup wheel grinding is composed of craterlike morphologies and slender cracks, with depth ranging from ∼6.2 to ∼13.2  μm under the specified grinding parameters. With the help of the proposed model, an optimized grinding strategy is suggested for realizing fine subsurface integrity as well as high removal rate, which can alleviate the workload of subsequent lapping and polishing.

  13. The Manufacture of the Grinding Wheels Based on the Ca–K Geopolymer Matrix

    Czech Academy of Sciences Publication Activity Database

    Perná, Ivana; Hanzlíček, Tomáš; Boura, P.; Lučaník, A.

    2016-01-01

    Roč. 31, č. 5 (2016), s. 667-672 ISSN 1042-6914 Institutional support: RVO:67985891 Keywords : geopolymer * grinding * wheel * low-temperature * industrial * manufacturing * technology Subject RIV: DM - Solid Waste and Recycling Impact factor: 2.274, year: 2016

  14. On-machine measurement of the grinding wheels' 3D surface topography using a laser displacement sensor

    Science.gov (United States)

    Pan, Yongcheng; Zhao, Qingliang; Guo, Bing

    2014-08-01

    A method of non-contact, on-machine measurement of three dimensional surface topography of grinding wheels' whole surface was developed in this paper, focusing on an electroplated coarse-grained diamond grinding wheel. The measuring system consists of a Keyence laser displacement sensor, a Keyence controller and a NI PCI-6132 data acquisition card. A resolution of 0.1μm in vertical direction and 8μm in horizontal direction could be achieved. After processing the data by LabVIEW and MATLAB, the 3D topography of the grinding wheel's whole surface could be reconstructed. When comparing the reconstructed 3D topography of the grinding wheel's marked area to its real topography captured by a high-depth-field optical digital microscope (HDF-ODM) and scanning electron microscope (SEM), they were very similar to each other, proving that this method is accurate and effective. By a subsequent data processing, the topography of every grain could be extracted and then the active grain number, the active grain volume and the active grain's bearing ration could be calculated. These three parameters could serve as the criterion to evaluate the grinding performance of coarse-grained diamond grinding wheels. Then the performance of the grinding wheel could be evaluated on-machine accurately and quantitatively.

  15. MICRO-ARC DIELECTRIC COATINGS ON ALUMINUM ALLOYS OF GRINDING WHEEL FRAMEWORKS

    Directory of Open Access Journals (Sweden)

    Yury GUTSALENKO

    2018-05-01

    Full Text Available It is presented the development of local electrically insulating coatings for tool of the technologies of high-efficient processing with the introduction the energy of electrical discharges into the cutting zone to maintain a working capacity of grinding wheels with diamond-metal composition of the working part. Development is an alternative to the electrical insulation upgrade of spindle units of universal grinding machines. The dielectric properties of micro-arc oxide coatings on deformable aluminum alloys formed on an alternating current in the regime of an arbitrarily falling power in alkali-silicate solutions have been studied. Information about the features of practical implementation of development is given.

  16. A novel method of freeform surface grinding with a soft wheel based on industrial robots

    Science.gov (United States)

    Sha, Sheng-chun; Guo, Xiao-ling

    2011-08-01

    In order to meet the growing demand for high-quality images, optical elements of freeform surface are more and more applied to imaging system. However the fabrication of freeform surface optical elements is much more difficult than that of traditional spherical ones. Recent research on freeform surface manufacture often deals with precision machine tools which have limitations on dimensions and are always expensive. Little has been researched on industrial robots. In this paper, a new method of freeform surface grinding based on industrial robots was found. This method could be applied to both whole surface grinding as well as partial surface grinding. The diameter of lenses to be ground would not be restricted to the machine tool's size. In this method a high-speed-rotating soft wheel was used. The relation between removing amount and grinding time which could be called removing function was established and measured. The machining precision was achieved by means of controlling the grinding time instead of the machine tool or industrial robot itself. There are two main factors affecting the removing function: i).rotating speed of the soft wheel; ii).pressure between the wheel and the work piece. In this paper, two groups of experiments have been conducted. One is the removing function tested at constant rotating speed while under different pressure. The other is that tested under a certain pressure with variable speed. Tables and curves which can show the effect of speed and pressure on the removing efficiency have been obtained. Cause for inaccuracy between experiment data and calculated result according to the theory and the non-linearity in the curves was analyzed. Through these analyses the removing function could be concluded under certain condition including rotating speed and pressure. Finally several experiments were performed to verify the appropriateness of the removing function. It could also be concluded that this method was more efficient in comparison

  17. Force characteristics in continuous path controlled crankpin grinding

    Science.gov (United States)

    Zhang, Manchao; Yao, Zhenqiang

    2015-03-01

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

  18. Diamond grinding wheels production study with the use of the finite element method.

    Science.gov (United States)

    Kundrák, J; Fedorovich, V; Markopoulos, A P; Pyzhov, I; Kryukova, N

    2016-11-01

    Research results on 3D modeling of the diamond grain and its bearing layer when sintering diamond grinding wheels are provided in this paper. The influence of the main characteristics of the wheel materials and the wheel production process, namely the quantity of metallic phase within diamond grain, coefficient of thermal expansion of the metallic phase, the modulus of elasticity of bond material and sintering temperature, on the internal stresses arising in grains is investigated. The results indicate that the stresses in the grains are higher in the areas around the metallic phase. Additionally, sintering temperature has the greatest impact on the stresses of the grain-metallic phase-bond system regardless of the type of the bond. Furthermore, by employing factorial design for the carried out finite element model, a mathematical model that reflects the impact of these factors on the deflected mode of the diamond grain-metallic phase-bond material system is obtained. The results of the analysis allow for the identification of optimal conditions for the efficient production of improved diamond grinding wheels. More specifically, the smallest stresses are observed when using the metal bond with modulus of elasticity 204 GPa, the quantity of metallic phase in diamond grain of not higher than 7% and coefficient of thermal expansion of 1.32 × 10 -5  1/K or lower. The results obtained from the proposed 3D model can lead to the increase in the diamond grains utilization and improve the overall efficiency of diamond grinding.

  19. Cylindrical plunge grinding of difficult to grind materials

    International Nuclear Information System (INIS)

    Nakajima, Toshikatsu; Uno, Yoshiyuki; Kayahara, Masayuki.

    1983-01-01

    Cylindrical plunge grinding processes of titanium alloy and nickel-base superalloys with various kinds of conventional grinding wheels, which are known as difficult to grind materials, are experimentally investigated, analyzing size generation process, grinding force, surface roughness, wheel wear, grinding ratio and so on. For grinding titanium alloy Ti-6Al-4V, GC grinding wheel yields most superior grinding results which leads to lower grinding force, smaller residual stock, less wheel wear and higher grinding ratio up to about 3 with GC 80 L 9 V wheel. Then, for grinding nickelbase superalloys Waspaloy and Rene 41, WA 150 L 9 V wheel yields better grinding results in surface roughness, wheel wear, grinding ratio without chatter vibration though grinding force is higher, and the grinding ratio about 3 is obtained. Furthermore, higher plunge speed and speed ratio result in higher grinding efficiency though grinding force, surface roughness, wheel wear increase for grinding titanium alloy and nickel-base superalloys. (author)

  20. INTRODUCTION TO THE ANALYSIS OF THE MECHANICS OF THE DIAMOND GRINDING PROCESS WITH THE ACCOUNT OF WEAR OF WHEEL GRAINS

    Directory of Open Access Journals (Sweden)

    Feodor NOVIKOV

    2017-12-01

    Full Text Available The work is devoted to the theoretical analysis of the mechanics of the diamond grinding process, taking into account the wear of the wheel grains for scientifically based choice of optimal processing conditions. A multiplicative probabilistic approach to the generalization of the cutting profile of a diamond grinding wheel in its consideration in a state of some steady wear during processing is considered. This is achieved by working the wheel in a mode of properly established self-sharpening or with the use of effective dressing methods. In this case, the linear wear of individual grains of diamond abrasive located on the working surface of the grinding wheel and opened to mechanical contact with the material being processed is assumed to proportionally to the depth of the introduction of grain into it. The analytical dependence of the maximum thickness of the cut is presented, and the relationship between the maximum grain wear and the accepted universal relative characteristic of the steady wear with the operational parameters of the tool and the grinding mode is shown. The obtained results can be used in the development of analytical models of processing productivity and microgeometric engineering of the treated surface, new approaches to increasing the efficiency of diamond grinding. The research is based on modern technical possibilities of controlling the state of the cutting relief of diamond-abrasive tools, especially in electro-physical-mechanical grinding technologies, for example, using the diamond-spark method developed at the Kharkov Polytechnic Institute.

  1. Adhesive wear mechanism under combined electric diamond grinding

    Directory of Open Access Journals (Sweden)

    Popov Vyacheslav

    2017-01-01

    Full Text Available The article provides a scientific substantiation of loading of metal-bond diamond grinding wheels and describes the mechanism of contact interaction (interlocking of wheels with tool steel as well as its general properties having an influence on combined electric diamond grinding efficiency. The study concluded that a loaded layer can be formed in a few stages different by nature. It is known, that one of the causes of grinding degradation is a continuous loading of active grits (abrasive grinding tool by workpiece chips. It all affects the diamond grinding wheels efficiency and grinding ability with a result in increase of tool pressure, contact temperature and wheels specific removal rate. Science has partially identified some various methods to minimize grinding wheel loading, however, as to loading of metal-bond diamond grinding wheels the search is still in progress. Therefore, research people have to state, that in spite of the fact that the wheels made of cubic boron nitride are of little use as applied to ceramic, ultrahard, hard-alloyed hard-to-machine and nano-materials of the time, but manufactures have to apply cubic boron nitride wheels wherein diamond ones preferable.

  2. On modelling the interaction between two rotating bodies with statistically distributed features: an application to dressing of grinding wheels

    Science.gov (United States)

    Spampinato, A.; Axinte, D. A.

    2017-12-01

    The mechanisms of interaction between bodies with statistically arranged features present characteristics common to different abrasive processes, such as dressing of abrasive tools. In contrast with the current empirical approach used to estimate the results of operations based on attritive interactions, the method we present in this paper allows us to predict the output forces and the topography of a simulated grinding wheel for a set of specific operational parameters (speed ratio and radial feed-rate), providing a thorough understanding of the complex mechanisms regulating these processes. In modelling the dressing mechanisms, the abrasive characteristics of both bodies (grain size, geometry, inter-space and protrusion) are first simulated; thus, their interaction is simulated in terms of grain collisions. Exploiting a specifically designed contact/impact evaluation algorithm, the model simulates the collisional effects of the dresser abrasives on the grinding wheel topography (grain fracture/break-out). The method has been tested for the case of a diamond rotary dresser, predicting output forces within less than 10% error and obtaining experimentally validated grinding wheel topographies. The study provides a fundamental understanding of the dressing operation, enabling the improvement of its performance in an industrial scenario, while being of general interest in modelling collision-based processes involving statistically distributed elements.

  3. Sintering of new SiC-Phosphate composite materials for grinding wheels fabrication

    Directory of Open Access Journals (Sweden)

    Silva, R. F.

    2004-04-01

    Full Text Available The effect of several variables such as molar ratio P2O5/B2O3 (X, temperature and heating cycle on the strength of chemically bonded SiC materials for grinding wheels fabrication was studied. It was shown that the highest compressive strength (52.4 MPa could be obtained using an optimal molar ratio X = 4.5 and a multiple step heating cycle up to a sintering temperature of 800oC. DTA, XRD, SEM and dilatometrical analysis were performed to follow the different stages of the structural development.

    Se estudia el efecto de diferentes variables tales como la razón molar P2O5/B2O3(X, temperatura y ciclo de calentamieno sobre la resistencia de materiales de SiC aglomerados quimicamente para la fabricación de muelas arasivas. Se ha comprobado que la más alta resistencia a la compresión (52,4MPa pueda obtenerse usando una razón molar òptima x= 4,5 y un ciclo de calentamiento en múltiples etapas hasta la temperatura de 800º C. Estudios mediante ATD, DRX, MEB y análisis dilatométricos fueron llevados a cabo para seguir las diferentes etapas del desarrollo microestructura.

  4. Load-bearing processes in agricultural wheel-soil systems

    NARCIS (Netherlands)

    Tijink, F.G.J.

    1988-01-01

    In soil dynamics we distinguish between loosening and loadbearing processes. Load-bearing processes which can occur under agricultural rollers, wheels, and tyres are dealt with In this dissertation.

    We classify rollers, wheels, and tyres and treat some general aspects of these

  5. Lateral ring metal elastic wheel absorbs shock loading

    Science.gov (United States)

    Galan, L.

    1966-01-01

    Lateral ring metal elastic wheel absorbs practically all shock loading when operated over extremely rough terrain and delivers only a negligible shock residue to associated suspension components. The wheel consists of a rigid aluminum assembly to which lateral titanium ring flexible elements with treads are attached.

  6. Analysis of the influence of infeed rate and cutting fluid on cylindrical grinding processes using a conventional wheel

    Directory of Open Access Journals (Sweden)

    Bianchi Eduardo Carlos

    2004-01-01

    Full Text Available New worldwide trends such as globalization have rendered grinding processes increasingly important for industry, making it essential to perform in-depth studies of variations in grinding process parameters in the pursuit of greater cost effectiveness. This paper presents a comparative analysis of three different infeed rates, using a conventional grinding wheel on quenched and tempered D2 steel workpieces. Higher infeed rates are known to be correlated with shorter grinding times, rendering the process more economically attractive. Two different coolant fluids, 5% emulsion and pure oil, were used. The tests were carried out using the smallest possible amount of coolant and an optimized 5 mm diameter nozzle. The parameters analyzed were tangential force, specific energy, acoustic emission, roundness error and surface roughness. The surfaces of the workpieces were also examined by scanning electron microscopy (SEM. The results revealed that increased infeed rates could reduce processing times without compromising the quality of the workpiece profile, thereby reducing the cost of the process. The best cutting fluid, albeit more harmful to human health and less environmentally friendly, was found to be pure oil.

  7. Determination of the boundary conditions of the grinding load in ball mills

    Science.gov (United States)

    Sharapov, Rashid R.

    2018-02-01

    The prospects of application in ball mills for grinding cement clinker with inclined partitions are shown. It is noted that ball mills with inclined partitions are more effective. An algorithm is proposed for calculating the power consumed by a ball mill with inclined inter-chamber partitions in which an axial movement of the ball load takes place. The boundary conditions in which the ball load is located are determined. The equations of bounding the grinding load are determined. The behavior of a grinding load is considered in view of the characteristic cross sections. The coordinates of the centers of gravity of the grinding load with a definite step and the shape of the cross sections are determined. It is theoretically shown that grinding load in some parts of the ball mill not only consumes, but also helps to rotate the ball mill. Methods for calculating complex analytical expressions for determining the coordinates of the centers of gravity of the grinding load under the conditions of its longitudinal motion have developed. The carried out researches allow to approach from the general positions to research of behavior of a grinding load in the ball mills equipped with various in-mill devices.

  8. Wheel set run profile renewing method effectiveness estimation

    OpenAIRE

    Somov, Dmitrij; Bazaras, Žilvinas; Žukauskaite, Orinta

    2010-01-01

    At all the repair enterprises, despite decreased rim wear-off resistance, after every grinding only geometry wheel profile parameters are renewed. Exploit wheel rim work edge decrease tendency is noticed what induces acquiring new wheels. This is related to considerable axle load and train speed increase and also because of wheel work edge repair method imperfection.

  9. Study of Micro-hardness of High-Speed W9Mo4Co8 Steel Plates in Pendulum Grinding by Abrasive Wheel Periphery

    OpenAIRE

    Soler, Yakov Iosifovich; Nguyen, Van Canh

    2017-01-01

    In cutting tool assembly, grinding is the most important technological step of the finishing treatment, largely determining the workmanship. An increase of micro-hardness after grinding relative to the original one indicates the dominant role of abrasive tool force impact on the ground surface. A decrease, in contrast, evidences a significant softening under the influence of heat source. This research based on nonparametric statistics to predict the effect of wheel characteristics with abrasi...

  10. Maximum allowable load on wheeled mobile manipulators

    International Nuclear Information System (INIS)

    Habibnejad Korayem, M.; Ghariblu, H.

    2003-01-01

    This paper develops a computational technique for finding the maximum allowable load of mobile manipulator during a given trajectory. The maximum allowable loads which can be achieved by a mobile manipulator during a given trajectory are limited by the number of factors; probably the dynamic properties of mobile base and mounted manipulator, their actuator limitations and additional constraints applied to resolving the redundancy are the most important factors. To resolve extra D.O.F introduced by the base mobility, additional constraint functions are proposed directly in the task space of mobile manipulator. Finally, in two numerical examples involving a two-link planar manipulator mounted on a differentially driven mobile base, application of the method to determining maximum allowable load is verified. The simulation results demonstrates the maximum allowable load on a desired trajectory has not a unique value and directly depends on the additional constraint functions which applies to resolve the motion redundancy

  11. High Performance Grinding and Advanced Cutting Tools

    CERN Document Server

    Jackson, Mark J

    2013-01-01

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

  12. Experimental studies of breaking of elastic tired wheel under variable normal load

    Science.gov (United States)

    Fedotov, A. I.; Zedgenizov, V. G.; Ovchinnikova, N. I.

    2017-10-01

    The paper analyzes the braking of a vehicle wheel subjected to disturbances of normal load variations. Experimental tests and methods for developing test modes as sinusoidal force disturbances of the normal wheel load were used. Measuring methods for digital and analogue signals were used as well. Stabilization of vehicle wheel braking subjected to disturbances of normal load variations is a topical issue. The paper suggests a method for analyzing wheel braking processes under disturbances of normal load variations. A method to control wheel baking processes subjected to disturbances of normal load variations was developed.

  13. Effect of machinery wheel load on grass yield

    DEFF Research Database (Denmark)

    Green, Ole; Jørgensen, Rasmus Nyholm; Kristensen, Kristian

    2010-01-01

    Effect of machinery wheel load on grass   Ole Green1, Rasmus N. Jørgensen2, Kristian Kristensen3, René Gislum3, Dionysis Bochtis1, & Claus G. Sørensen1   1University of Aarhus, Dept. of Agricultural Engineering 2University of Southern Denmark, Inst. of Chemical Eng., Biotechnology and Environmental...... 3University of Aarhus, Dept. of Genetics and Biotechnology   Corresponding author: Ole Green Address & e-mail: Research Centre Foulum, Blichers Allé 20, 8830 Tjele. Ole.Green@agrsci.dk     Abstract   Different traffic intensities have been shown to have a negative influence on the yield of grass...... and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16 different traffic intensities with 35 replicates and 1 traffic free treatment with 245 replicates, totalling 17...

  14. Load theory behind the wheel; perceptual and cognitive load effects.

    Science.gov (United States)

    Murphy, Gillian; Greene, Ciara M

    2017-09-01

    Perceptual Load Theory has been proposed as a resolution to the longstanding early versus late selection debate in cognitive psychology. There is much evidence in support of Load Theory but very few applied studies, despite the potential for the model to shed light on everyday attention and distraction. Using a driving simulator, the effect of perceptual and cognitive load on drivers' visual search was assessed. The findings were largely in line with Load Theory, with reduced distractor processing under high perceptual load, but increased distractor processing under high cognitive load. The effect of load on driving behaviour was also analysed, with significant differences in driving behaviour under perceptual and cognitive load. In addition, the effect of perceptual load on drivers' levels of awareness was investigated. High perceptual load significantly increased inattentional blindness and deafness, for stimuli that were both relevant and irrelevant to driving. High perceptual load also increased RTs to hazards. The current study helps to advance Load Theory by illustrating its usefulness outside of traditional paradigms. There are also applied implications for driver safety and roadway design, as the current study suggests that perceptual and cognitive load are important factors in driver attention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. Preparation and properties of bisphenol-F based boron-phenolic resin/modified silicon nitride composites and their usage as binders for grinding wheels

    International Nuclear Information System (INIS)

    Lin, Chun-Te; Lee, Hsun-Tsing; Chen, Jem-Kun

    2015-01-01

    Highlights: • Bisphenol-F based boron-phenolic resins (B-BPF) with B−O bonds were synthesized. • The modified silicon nitride (m-SiN) was well dispersed and adhered in the B-BPF. • B-BPF/m-SiN composites have good thermal resistance and mechanical properties. • The grinding wheels bound by B-BPF/m-SiN have excellent grinding quality. - Abstract: In this study, phenolic resins based on bisphenol-F (BPF) were synthesized. Besides, ammonium borate was added in the synthesis process of BPF to form the bisphenol-F based boron-phenolic resins (B-BPF). The glass transition temperature, thermal resistance, flexural strength and hardness of B-BPF are respectively higher than those of BPF. This is due to the presence of new cross-link B−O bonds in the B-BPF. In addition, the 3-aminopropyltriethoxysilane modified silicon nitride powders (m-SiN) were fully mixed with B-BPF to form the B-BPF/m-SiN composites. The thermal resistance and mechanical properties of the B-BPF/m-SiN are promoted by the well-dispersed and well-adhered m-SiN in these novel polymer/ceramics composites. The results of grinding experiments indicate that the grinding wheels bound by the B-BPF/m-SiN have better grinding quality than those bound by the BPF. Thus the B-BPF/m-SiN composites are better binding media than the BPF resins

  16. Crush Grinding

    International Nuclear Information System (INIS)

    Nguyen, T.Q.

    2005-01-01

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

  17. Grinding Fluid Jet Characteristics and Their Effect on a Gear Profile Grinding Process

    Directory of Open Access Journals (Sweden)

    Philip Geilert

    2017-10-01

    Full Text Available Profile gear grinding is characterized by a high level of achievable process performance and workpiece quality. However, the wide contact length between the workpiece and the grinding wheel is disadvantageous for the fluid supply to the contact zone and leads to the risk of locally burning the workpiece surface. For the reduction of both the thermal load and the risk of thermo-mechanical damage, the usage of a grinding fluid needs to be investigated and optimized. For this purpose, different kinds of grinding fluid nozzles were tested, which provide different grinding fluid jet characteristics. Through a specific design of the nozzles, it is possible to control the fluid flow inside the nozzle. It was found that this internal fluid flow directly influences the breakup of the coolant fluid jet. There are three groups of jet breakup (“droplet”, “wave & droplet”, and “atomization”. The first experimental results show that the influence of the jet breakup on the process performance is significant. The “wave & droplet” jet breakup can achieve a high process performance, in contrast to the “atomization” jet breakup. It can therefore be assumed that the wetting of the grinding wheel by the grinding fluid jet is significantly influenced by the jet breakup.

  18. AUTOMATION OF IN FEED CENTERLESS GRINDING MACHINE

    OpenAIRE

    Piyusha P. Jadhav*, Sachin V. Lomte, Sudhir Surve

    2017-01-01

    In-feed centerless grinding technique offers a major contribution to the industries. This is the alternative in-feed centerless grinding technique using regulating wheel. Mainly centerless grinding is divided in three types, and those are End feed, in-feed and through feed Centerless grinding. This paper mainly deals with low cost automation on in-feed Centerless grinding machine using regulating wheel suitable for multiple in-feed type jobs. It deals with the development of a Centerless grin...

  19. Dynamic analysis of elastic rubber tired car wheel breaking under variable normal load

    Science.gov (United States)

    Fedotov, A. I.; Zedgenizov, V. G.; Ovchinnikova, N. I.

    2017-10-01

    The purpose of the paper is to analyze the dynamics of the braking of the wheel under normal load variations. The paper uses a mathematical simulation method according to which the calculation model of an object as a mechanical system is associated with a dynamically equivalent schematic structure of the automatic control. Transfer function tool analyzing structural and technical characteristics of an object as well as force disturbances were used. It was proved that the analysis of dynamic characteristics of the wheel subjected to external force disturbances has to take into account amplitude and phase-frequency characteristics. Normal load variations impact car wheel braking subjected to disturbances. The closer slip to the critical point is, the higher the impact is. In the super-critical area, load variations cause fast wheel blocking.

  20. Effects of acute voluntary loaded wheel running on BDNF expression in the rat hippocampus.

    Science.gov (United States)

    Lee, Minchul; Soya, Hideaki

    2017-12-31

    Voluntary loaded wheel running involves the use of a load during a voluntary running activity. A muscle-strength or power-type activity performed at a relatively high intensity and a short duration may cause fewer apparent metabolic adaptations but may still elicit muscle fiber hypertrophy. This study aimed to determine the effects of acute voluntary wheel running with an additional load on brain-derived neurotrophic factor (BDNF) expression in the rat hippocampus. Ten-week old male Wistar rats were assigned randomly to a (1) sedentary (Control) group; (2) voluntary exercise with no load (No-load) group; or (3) voluntary exercise with an additional load (Load) group for 1-week (acute period). The expression of BDNF genes was quantified by real-time PCR. The average distance levels were not significantly different in the No-load and Load groups. However, the average work levels significantly increased in the Load group. The relative soleus weights were greater in the No-load group. Furthermore, loaded wheel running up-regulated the BDNF mRNA level compared with that in the Control group. The BDNF mRNA levels showed a positive correlation with workload levels (r=0.75), suggesting that the availability of multiple workload levels contributes to the BDNF-related benefits of loaded wheel running noted in this study. This novel approach yielded the first set of findings showing that acute voluntary loaded wheel running, which causes muscular adaptation, enhanced BDNF expression, suggesting a possible role of high-intensity short-term exercise in hippocampal BDNF activity. ©2017 The Korean Society for Exercise Nutrition

  1. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines; protective....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than... the wheel. (3) Safety washers. (b) Grinding wheels shall be operated within the specifications of the...

  2. Prediction of bead area contact load at the tire-wheel interface using NASTRAN

    Science.gov (United States)

    Chen, C. H. S.

    1982-01-01

    The theoretical prediction of the bead area contact load at the tire wheel interface using NASTRAN is reported. The application of the linear code to a basically nonlinear problem results in excessive deformation of the structure and the tire-wheel contact conditions become impossible to achieve. A psuedo-nonlinear approach was adopted in which the moduli of the cord reinforced composite are increased so that the computed key deformations matched that of the experiment. Numerical results presented are discussed.

  3. Soil mechanical stresses in high wheel load agricultural field traffic: a case study

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    2017-01-01

    highly skewed. Across tyres, the maximum stress in the contact area correlated linearly with, but was much higher than, the mean ground pressure. For each of the three soil depths, the maximum stresses under the tyres were significantly correlated with the wheel load, but not with other loading......Subsoil compaction is a serious long-term threat to soil functions. Only a few studies have quantified the mechanical stresses reaching deep subsoil layers for modern high wheel load machinery. In the present study we measured the vertical stresses in the tyre–soil contact area and at 0.3, 0...

  4. Tire-rim interface pressure of a commercial vehicle wheel under radial loads: theory and experiment

    Science.gov (United States)

    Wan, Xiaofei; Shan, Yingchun; Liu, Xiandong; He, Tian; Wang, Jiegong

    2017-11-01

    The simulation of the radial fatigue test of a wheel has been a necessary tool to improve the design of the wheel and calculate its fatigue life. The simulation model, including the strong nonlinearity of the tire structure and material, may produce accurate results, but often leads to a divergence in calculation. Thus, a simplified simulation model in which the complicated tire model is replaced with a tire-wheel contact pressure model is used extensively in the industry. In this paper, a simplified tire-rim interface pressure model of a wheel under a radial load is established, and the pressure of the wheel under different radial loads is tested. The tire-rim contact behavior affected by the radial load is studied and analyzed according to the test result, and the tire-rim interface pressure extracted from the test result is used to evaluate the simplified pressure model and the traditional cosine function model. The results show that the proposed model may provide a more accurate prediction of the wheel radial fatigue life than the traditional cosine function model.

  5. The rolling motion of an eccentrically loaded wheel

    Science.gov (United States)

    Theron, W. F. D.

    2000-09-01

    This article discusses the rolling motion on a rough plane of a wheel whose center of mass does not coincide with the axis; for example, when a heavy particle is fixed to the rim of a rigid hoop. In cases with large eccentricity, the resulting motion is surprisingly complex, with four phases being identified, namely rolling (without slipping), spinning, skidding, and "hopping," by which is meant that the wheel actually leaves the plane. The main result of this analysis is the identification of the conditions that are required for hopping to occur. A second result is that faster than gravity accelerations occur when the mass of the particle is greater than the mass of the hoop. Massless hoops are briefly discussed as a special case of the general results.

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

    Science.gov (United States)

    Balan, A S S; Vijayaraghavan, L; Krishnamurthy, R; Kuppan, P; Oyyaravelu, R

    2016-09-01

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

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

    Directory of Open Access Journals (Sweden)

    A.S.S. Balan

    2016-09-01

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

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

    Science.gov (United States)

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

    2005-09-27

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

  9. Impact on Clover-Grass Yield from Wheel Load and Tyre Pressure

    DEFF Research Database (Denmark)

    Green, Ole; Jørgensen, Rasmus Nyholm; Sørensen, Claus Aage Grøn

    2009-01-01

    Traffic intensities have been shown to have a negative influence on the yield of grass and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16 different traffi...

  10. The effect of cognitive load on adaptation to differences in steering wheel force feedback level

    NARCIS (Netherlands)

    Anand, S.; Terken, J.; Hogema, J.

    2013-01-01

    In an earlier study it was found that drivers can adjust quickly to different force feedback levels on the steering wheel, even for such extreme levels as zero feedback. It was hypothesized that, due to lack of cognitive load, participants could easily and quickly learn how to deal with extreme

  11. Lathe converted for grinding aspheric surfaces

    Science.gov (United States)

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

    1964-01-01

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

  12. Surface grinding of intermetallic titanium aluminides

    CERN Document Server

    Gröning, Holger Andreas

    2014-01-01

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

  13. A study of grinding characteristic of ferrule

    International Nuclear Information System (INIS)

    Lee, S. W.; Choi, H. Z.; Choi, Y. J.; Ahn, G. J.

    2003-01-01

    As recently optical communication industry is developed, request of optical communication part is increased. Ferrule is very important part which determines transmission efficiency and quality of information in the optical communication part. Most of ferrule processes are grinding which request high processing precision. Particularly, concentricity and cylindricity of inner and outer diameter is very important. The co-axle grinding process of ferrule is to make its concentricity all of uniform before centerless grinding. Surface integrity of ferrule is affected by kind of grinding wheels, grinding conditions, and characteristic of workpiece and equipment. In this study, surface integrity of workpiece according to change of grinding wheel speed, feed rate, regulating wheel speed and grinding force is investigate to improve the concentricity and roundness of ferrule from many experiments

  14. Dynamic axle and wheel loads identification: laboratory studies

    Science.gov (United States)

    Zhu, X. Q.; Law, S. S.

    2003-12-01

    Two methods have been reported by Zhu and Law to identify moving loads on the top of a bridge deck. One is based on the exact solution (ESM) and the other is based on the finite element formulation (FEM). Simulation studies on the effect of different influencing factors have been reported previously. This paper comparatively studies the performances of these two methods with experimental measurements obtained from a bridge/vehicle system in the laboratory. The strains of the bridge deck are measured when a model car moves across the bridge deck along different paths. The moving loads on the bridge deck are identified from the measured strains using these two methods, and the responses are reconstructed from the identified loads for comparison with the measured responses to verify the performances of these methods. Studies on the identification accuracy due to the effect of the number of vibration mode used, the number of measuring points and eccentricities of travelling paths are performed. Results show that the ESM could identify the moving loads individually or as axle loads when they are travelling at an eccentricity with the sensors located close to the travelling path of the forces. And the accuracy of the FEM is dependent on the amount of measured information used in the identification.

  15. A Special Fiber Optic Sensor for Measuring Wheel Loads of Vehicles on Highways

    Directory of Open Access Journals (Sweden)

    Norman W. Garrick

    2008-04-01

    Full Text Available This paper presents results from an investigation on a special optical fiber as a load sensor for application in Weigh-in-Motion (WIM systems to measure wheel loads of vehicles traveling at normal speed on highways. The fiber used has a unique design with two concentric light guiding regions of different effective optical path lengths, which has the potential to enable direct measurement of magnitudes as well as locations of forces acting at multiple points along a single fiber. The optical characteristic of the fiber for intended sensing purpose was first assessed by a simple fiber bending experiment and by correlating the bend radii with the output light signal intensities. A simple laboratory load transmitting/fiber bending device was then designed and fabricated to appropriately bend the optical fiber under applied loads in order to make the fiber work as load sensor. The device with the optical fiber was tested under a universal loading machine and an actual vehicle wheel in the laboratory. The test results showed a good relationship between the magnitude of the applied load and the output optical signal changes. The results also showed a good correlation between the time delay between the inner and outer core light pulses and the distance of the applied load as measured from the output end of the fiber.

  16. Characterizing Wheel-Soil Interaction Loads Using Meshfree Finite Element Methods: A Sensitivity Analysis for Design Trade Studies

    Science.gov (United States)

    Contreras, Michael T.; Trease, Brian P.; Bojanowski, Cezary; Kulakx, Ronald F.

    2013-01-01

    A wheel experiencing sinkage and slippage events poses a high risk to planetary rover missions as evidenced by the mobility challenges endured by the Mars Exploration Rover (MER) project. Current wheel design practice utilizes loads derived from a series of events in the life cycle of the rover which do not include (1) failure metrics related to wheel sinkage and slippage and (2) performance trade-offs based on grouser placement/orientation. Wheel designs are rigorously tested experimentally through a variety of drive scenarios and simulated soil environments; however, a robust simulation capability is still in development due to myriad of complex interaction phenomena that contribute to wheel sinkage and slippage conditions such as soil composition, large deformation soil behavior, wheel geometry, nonlinear contact forces, terrain irregularity, etc. For the purposes of modeling wheel sinkage and slippage at an engineering scale, meshfree nite element approaches enable simulations that capture su cient detail of wheel-soil interaction while remaining computationally feasible. This study implements the JPL wheel-soil benchmark problem in the commercial code environment utilizing the large deformation modeling capability of Smooth Particle Hydrodynamics (SPH) meshfree methods. The nominal, benchmark wheel-soil interaction model that produces numerically stable and physically realistic results is presented and simulations are shown for both wheel traverse and wheel sinkage cases. A sensitivity analysis developing the capability and framework for future ight applications is conducted to illustrate the importance of perturbations to critical material properties and parameters. Implementation of the proposed soil-wheel interaction simulation capability and associated sensitivity framework has the potential to reduce experimentation cost and improve the early stage wheel design proce

  17. Effect of core ceramic grinding on fracture behaviour of bilayered zirconia veneering ceramic systems under two loading schemes.

    Science.gov (United States)

    Jian, Yu-Tao; Tang, Tian-Yu; Swain, Michael V; Wang, Xiao-Dong; Zhao, Ke

    2016-12-01

    The aim of this in vitro study was to evaluate the effect of core ceramic grinding on the fracture behaviour of bilayered zirconia under two loading schemes. Interfacial surfaces of sandblasted zirconia disks (A) were ground with 80 (B), 120 (C) and 220 (D) grit diamond discs, respectively. Surface roughness and topographic analysis were performed using a confocal scanning laser microscope (CSLM) and a scanning electron microscopy (SEM). Relative monoclinic content was evaluated using X-ray diffraction analysis (XRD) then reevaluated after simulated veneer firing. Biaxial fracture strength (σ) and Weibull modulus (m) were calculated either with core in compression (subgroup Ac-Dc) or in tension (subgroup At-Dt). Facture surfaces were examined by SEM and energy dispersive X-ray spectroscopy (EDS). Maximum tensile stress at fracture was estimated by finite element analysis. Statistical data analysis was performed using Kruskal-Wallis and one-way ANOVA at a significance level of 0.05. As grit size of the diamond disc increased, zirconia surface roughness decreased (pgrinding. No difference in initial (p=0.519 for subgroups Ac-Dc) and final fracture strength (p=0.699 for subgroups Ac-Dc; p=0.328 for subgroups At-Dt) was found among the four groups for both loading schemes. While coarse grinding slightly increased final fracture strength reliability (m) for subgroups Ac-Dc. Two different modes of fracture were observed according to which material was on the bottom surface. Components of the liner porcelain remained on the zirconia surface after fracture for all groups. Technician grinding changed surface topography of zirconia ceramic material, but was not detrimental to the bilayered system strength after veneer application. Coarse grinding slightly improved the fracture strength reliability of the bilayered system tested with core in compression. It is recommended that veneering porcelain be applied directly after routine lab grinding of zirconia ceramic, and its

  18. Seasonal dynamics in wheel load-carrying capacity of a loam soil in the Swiss Plateau

    DEFF Research Database (Denmark)

    Gut, S.; Chervet, A.; Stettler, Matthias

    2015-01-01

    on in situ measurements of h, measurements of precompression stress at various h and simulations of soil stress. In this work, we concentrated on prevention of subsoil compaction. Calculations were made for different tyres (standard and low-pressure top tyres) and for soil under different tillage......Subsoil compaction is a major problem in modern agriculture caused by the intensification of agricultural production and the increase in weight of agricultural machinery. Compaction in the subsoil is highly persistent and leads to deterioration of soil functions. Wheel load-carrying capacity (WLCC......) is defined as the maximum wheel load for a specific tyre and inflation pressure that does not result in soil stress in excess of soil strength. The soil strength and hence WLCC is strongly influenced by soil matric potential (h). The aim of this study was to estimate the seasonal dynamics in WLCC based...

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

    International Nuclear Information System (INIS)

    Ghani, A.K.; Choudhury, I.A.; Ahim, M.B.

    1999-01-01

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

  20. The Pneumatic Actuators As Vertical Dynamic Load Simulators On Medium Weighted Wheel Suspension Mechanism

    Science.gov (United States)

    Ka'ka, Simon; Himran, Syukri; Renreng, Ilyas; Sutresman, Onny

    2018-02-01

    Almost all of road damage can be caused by dynamic loads of vehicles that fluctuate according to the type of vehicle that passes through. This study aims to calculate the vertical dynamic load of the vehicle actually occurs on road construction by the mechanism of vehicle wheel suspension. Pneumatic cylinders driven by pressurized air directly load the spring and shock absorber installed on the wheels of the vehicle. The load fluctuations of the medium weight categorized vehicles are determined by the regulation of the amount of pressurized air that enters into the pneumatic cylinder chamber, pushing the piston and connecting rods. The displacement that occurs during compression on the spring and shock absorber, is substituted into the equation of vehicle dynamic load while taking into account the spring stiffness constant, and the fluid or damper gas coefficient. The results show that the magnitude of the displacement when the compression force works has significant influences to the amount of vertical dynamic load of the vehicle that overlies the road construction. The presence of dynamic load of vehicles that fluctuates and repeats, also affects on the reduction of road ability to receive the load. Experimental results using pneumatic actuators instead of real dynamic vehicle loads illustrate the characteristics of the relationship between work pressure and dynamic load. If the working pressure of P2 (bar) is greater, the vertical dynamic load Ft (N) that overloads the road structure is also greater. The associate graphs show that the shock absorber has a greater ability to reduce dynamic load vertically that burden the road structure when compared with the ability of screw spring.

  1. Deformation and lifetime behaviour of cyclic loaded rail and wheel steels

    Energy Technology Data Exchange (ETDEWEB)

    Denne, B.; Lang, K.-H.; Loehe, D. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Werkstoffkunde 1

    2000-07-01

    Corrugation, shelling and squats are some unexpected technical problems caused by increasing service tonnage, increasing load of the rails and increasing train speed at Deutsche Bahn AG lines since the last decades. As the complex phenomena of rolling contact fatigue in the rail / wheel system is difficult to understand extensive investigations have to be done to describe the multiaxial rolling contact fatigue processes and to develop and verify multiaxial fatigue criteria and lifetime predictions. To reach this aim a reliable fatigue data base of the utilised steels is required. To obtain such data, specimens were worked out of rails and wheels used in high speed traffic. With these specimens the lifetime behaviour and the endurance limit were estimated from push-pull tests. For the rail steel stress and total strain controlled fatigue tests were performed. The resulting lifetime behaviour is compared. In the wheel there are several regions with different microstructures due to the heat treatment at the end of the manufacturing process. Specimens were taken from the wheel rim representing these different microstructures. With these specimens stress controlled fatigue tests were performed. The influence of the different microstructures on the deformation and lifetime behaviour is showed. (orig.)

  2. Understanding the Influence of Pressure and Radial Loads on Stress and Displacement Response of a Rotating Body: The Automobile Wheel

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available This paper highlights the use of the finite element technique for analyzing stress and displacement distributions in wheels of automotive vehicles when subject to the conjoint influence of inflation pressure and radial load. The most commonly used considerations in the design of the rotating body are elucidated. A potentially viable technique for finite element modeling of radial wheel, subjected to loading, is highlighted. The extrinsic influence of inflation pressure on performance of the rotating body, that is, the wheel, is rationalized.

  3. Grinding arrangement for ball nose milling cutters

    Science.gov (United States)

    Burch, C. F. (Inventor)

    1974-01-01

    A grinding arrangement for spiral fluted ball nose end mills and like tools includes a tool holder for positioning the tool relative to a grinding wheel. The tool is mounted in a spindle within the tool holder for rotation about its centerline and the tool holder is pivotably mounted for angular movement about an axis which intersects that centerline. A follower arm of a cam follower secured to the spindle cooperates with a specially shaped cam to provide rotation of the tool during the angular movement of the tool holder during the grinding cycle, by an amount determined by the cam profile. In this way the surface of the cutting edge in contact with the grinding wheel is maintained at the same height on the grinding wheel throughout the angular movement of the tool holder during the grinding cycle.

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

    DEFF Research Database (Denmark)

    Sudheesh, P. K.; Puthumana, Govindan

    2016-01-01

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

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

    DEFF Research Database (Denmark)

    Sudheesh, P. K.; Puthumana, Govindan

    2016-01-01

    in jig grinding, because of their uniformity and purity. In this paper, abrief review of the analysis of jig grinding process considering various research trends is presented. The areas highlighted are: optimization, selection of abrasives, selection of processing conditions and practical considerations....... The optimization of parameters in jig grinding process is important to maximize productivity and to improve quality. The abrasives of hard jig grinding wheels get blunt quickly so these are recommended to grind workpiece of low hardness and soft grinding wheels are recommended for hard material workpieces. The jig...

  6. Temperature calculations of heat loads in rotating target wheels exposed to high beam currents

    International Nuclear Information System (INIS)

    Greene, John P.; Gabor, Rachel; Neubauer, Janelle

    2001-01-01

    In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or 'wobbled' beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material

  7. Temperature calculations of heat loads in rotating target wheels exposed to high beam currents

    International Nuclear Information System (INIS)

    Greene, J. P.; Gabor, R.; Neubauer, J.

    2000-01-01

    In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or wobbled beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material

  8. Study of process of trueing diamond grinding wheels on metal bonds by method of free abrasive after processing of leucosapphire blanks

    Science.gov (United States)

    Fedonin, O. N.; Handozhko, A. V.; Fedukov, A. G.

    2018-03-01

    The problem of mechanical processing, in particular, grinding products from leucosapphire, is considered. The main problem with this treatment is the need to adjust the diamond tool. One of the methods of tool trueing using loose abrasive technique is considered. The results of a study on restoring the tool cutting ability, its shape and profile after straightening are given.

  9. Development of a Laser-Guided Deep-Hole Internal-Grinding Tool (Series 1) : Grinding Forces

    OpenAIRE

    Katsuki, Akio; Onikura, Hiromichi; Sajima, Takao; Park, Hyunkoo

    2005-01-01

    The laser-guided deep-hole internal grinding tool is developed to bore accurate and straight deep-holes with high surface quality. The tool consists of a grinding head, the front and rear actuators mounted on an actuator holder and a laser diode set in the back end of the holder. The grinding head consists of a diamond or CBN wheel, an air motor, and the piezoelectric actuators for the compensation of tool diameter. The grinding wheel is located eccentrically at the grinding head. The grindin...

  10. Gender differences in exerted forces and physiological load during pushing and pulling of wheeled cages by postal workers

    NARCIS (Netherlands)

    Van Der Beek, Allard J.; Kluver, B.D.R.; Frings-Dresen, M. H. W.; Hoozemans, M. J M

    The aim was to determine gender differences regarding exerted forces and physiological load during push/pull tasks simulating the daily working practice of postal workers. Eight female and four male workers handled four-wheeled cages under eight conditions corresponding to the cage weight (130, 250,

  11. DEFINITION OF LOCOMOTIVE TRACTION FORCE WITH REGARD TO UNEVEN LOADING OF WHEEL-MOTOR BLOCK

    Directory of Open Access Journals (Sweden)

    B. Ye. Bodnar

    2013-11-01

    Full Text Available Purpose. The article describes the most common methods for determining the locomotive traction force. Solving the tasks of traction calculations involves determination of the forces influencing the train at every point of the way. When choosing a rational trajectory of the train motion and the development of operational regulations of train driving it is necessary to determine the actual value of the locomotive traction force. Considering various factors, power value of traction electric motor of locomotive may have significant differences. Advancement of the operational definition system of the locomotive traction force during the calculations by electrical parameters of traction electric motor with regard to uneven load of wheel-motor block is the purpose of the article. Methodology. The method of determining the traction force of locomotives and diesel locomotives with electric transmission, which is based on primary data acquisition of traction electric engines of direct current behavior, was proposed. Sensors and their integration into the electrical circuitry of the locomotive in order to get the data in digital form and for operational calculation of the each traction motor mode and the definition of locomotive traction force are presented. Findings. The experimental investigation of the system of locomotive traction force determination with the electric traction motor ED-105 was offered. A comparison of electrical and mechanical power of the electric motor was conducted. Originality. The system of locomotives power operational definition, which takes into account the variable electro-mechanical factors of wheel and motor blocks and increases the accuracy of the calculations, was proposed. Practical value. The system is a part of an onboard complex in definition of energy-efficient regimes for trains movement and provides the definition of accelerating and decelerating forces.

  12. SELF-DIAGNOSIS METHOD FOR CHECKING THE WAYSIDE SYSTEMS FOR WHEEL-RAIL VERTICAL LOAD MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Daniele CORTIS

    2017-12-01

    Full Text Available Nowadays, wayside measurement systems of wheel-rail contact forces have acquired great relevance for the monitoring of rolling stock, especially for freight trains. Thanks to these solutions, infrastructure managers can check and monitor the status of rolling stock and, when necessary, impose corrective actions for the railway companies. On the other hand, the evaluation of contact forces is part of the rolling stock authorisation process [1] and a mainstone for the study of the running stability. The data provided by these measurements could give useful information to correlate the wear of the track with the frequency of applied loads, helping in the development of a better maintenance strategy of railway networks [2]. In this paper, the monitoring of vertical forces is based on the SMCV (Vertical Loads Monitoring System method, where shear strains of the rail web are measured with a simple combination of four electrical strain gauges, placed on both sides of the rail web along each span. The research has identified self-diagnosis methods for the SMCV system to ensure the reliability and the quality of the measurements and to extend the knowledge of the system. The recorded signals have been processed and converted into easily interpretable physical quantities by means of MATLAB® algorithm.

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

    NARCIS (Netherlands)

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

    1999-01-01

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

  14. An approach for modeling the influence of wheel tractor loads and vibration frequencies on soil compaction

    Science.gov (United States)

    Verotti, M.; Servadio, P.; Belfiore, N. P.; Bergonzoli, S.

    2012-04-01

    Both soil compaction and ground vibration are forms of environmental degradation that may be understood in the context of the vehicle-soil interaction process considered (Hildebrand et al., 2008). The transit of tractors on agricultural soil is often the main cause of soil compaction increasing. As known, this can be a serious problems for tillage and sowing and therefore the influence of all the affecting factors have been extensively studied in the last decades in order to understand their impact on the biosystem. There are factors related to the climate, namely to the rainfalls and temperature, and many others. Hence, it is not simple to figure out a complete model for predicting an index of compaction, for a given situation. Soil compaction models are important tools for controlling soil compaction due to agricultural field traffic and they are potentially useful technique to provide information concerning correct soil management. By means of such models, strategies and recommendations for prevention of soil compaction may be developed and specific advice may be given to farmers and advisers. In order to predict field wheeled and tracked vehicle performance, some empirical methods, used for off-road vehicle, were applied by Servadio (2010) on agricultural soil. The empirical indexes included, besides the soil strength, the load carried by the tire or track, some technical characteristics of the tire or track of the vehicle (tire or track width, tire or track wheel diameter, unloaded tire section height, number of wheel station in one track, tire deflection, total length of the belt track, the track pitch) as well as the vehicle passes. They have been validated with the tests results of agricultural vehicles over a range of soil in central Italy. Among the parameters which affect soil compaction, the water content of the soil, the axle load and number of vehicle passes proved to be the most important ones. The present paper concerns mainly vehicle

  15. Grinding Parts For Automatic Welding

    Science.gov (United States)

    Burley, Richard K.; Hoult, William S.

    1989-01-01

    Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

  16. THE EIGHT-WHEEL LOCOMOTIVE DC3 WITH THE SECOND TYPE OF RATING UNLOADING AND ADDITIONAL LOADING OF WHEELS AND DEFLECTIONS SPRING SUSPENSION DURING TRACTION EFFORTS TRANSFER FROM BOGIES TO BODY WITH USING RECLINING TRACTIONS

    Directory of Open Access Journals (Sweden)

    V. A. Bratash

    2010-11-01

    Full Text Available In the article the calculation formulas for determination of unloadings (finishings loadings of wheels and bendings of a spring suspension of 8-wheel electric locomotive DS 3 with the hauling transmission of the second kind at the transmission of tractive forces from the bogies to the body through sloping tractions are presented. Numerical calculations are executed on the example of mainline freight-and-passenger electric locomotive DS 3.

  17. Safety of stationary grinding machines - impact resistance of work zone enclosures.

    Science.gov (United States)

    Mewes, Detlef; Adler, Christian

    2017-09-01

    Guards on machine tools are intended to protect persons from being injured by parts ejected with high kinetic energy from the work zone of the machine. Stationary grinding machines are a typical example. Generally such machines are provided with abrasive product guards closely enveloping the grinding wheel. However, many machining tasks do not allow the use of abrasive product guards. In such cases, the work zone enclosure has to be dimensioned so that, in case of failure, grinding wheel fragments remain inside the machine's working zone. To obtain data for the dimensioning of work zone enclosures on stationary grinding machines, which must be operated without an abrasive product guard, burst tests were conducted with vitrified grinding wheels. The studies show that, contrary to widely held opinion, narrower grinding wheels can be more critical concerning the impact resistance than wider wheels although their fragment energy is smaller.

  18. Critical study of high efficiency deep grinding

    OpenAIRE

    Johnstone, lain

    2002-01-01

    The recent years, the aerospace industry in particular has embraced and actively pursued the development of stronger high performance materials, namely nickel based superalloys and hardwearing steels. This has resulted in a need for a more efficient method of machining, and this need was answered with the advent of High Efficiency Deep Grinding (HEDG). This relatively new process using Cubic Boron Nitride (CBN) electroplated grinding wheels has been investigated through experim...

  19. Precision diamond grinding of ceramics and glass

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-12-01

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

  20. Elucidating Grinding Mechanism by Theoretical and Experimental Investigations

    Directory of Open Access Journals (Sweden)

    AMM Sharif Ullah

    2018-02-01

    Full Text Available Grinding is one of the essential manufacturing processes for producing brittle or hard materials-based precision parts (e.g., optical lenses. In grinding, a grinding wheel removes the desired amount of material by passing the same area on the workpiece surface multiple times. How the topography of a workpiece surface evolves with these passes is thus an important research issue, which has not yet been addressed elaborately. The present paper tackles this issue from both the theoretical and the experimental points of view. In particular, this paper presents the results of experimental and theoretical investigations on the multi-pass surface grinding operations where the workpiece surface is made of glass and the grinding wheel consists of cBN abrasive grains. Both investigations confirm that a great deal of stochasticity is involved in the grinding mechanism, and the complexity of the workpiece surface gradually increases along with the number of passes.

  1. Elucidating Grinding Mechanism by Theoretical and Experimental Investigations.

    Science.gov (United States)

    Ullah, Amm Sharif; Caggiano, Alessandra; Kubo, Akihiko; Chowdhury, M A K

    2018-02-09

    Grinding is one of the essential manufacturing processes for producing brittle or hard materials-based precision parts (e.g., optical lenses). In grinding, a grinding wheel removes the desired amount of material by passing the same area on the workpiece surface multiple times. How the topography of a workpiece surface evolves with these passes is thus an important research issue, which has not yet been addressed elaborately. The present paper tackles this issue from both the theoretical and the experimental points of view. In particular, this paper presents the results of experimental and theoretical investigations on the multi-pass surface grinding operations where the workpiece surface is made of glass and the grinding wheel consists of cBN abrasive grains. Both investigations confirm that a great deal of stochasticity is involved in the grinding mechanism, and the complexity of the workpiece surface gradually increases along with the number of passes.

  2. Control of grinding polygonal surfaces

    Directory of Open Access Journals (Sweden)

    Юрій Володимирович Петраков

    2017-12-01

    Full Text Available Grinding of non-round surfaces, in particular polygonal surfaces of dies, is characterized by substantial non stationary. At different sections of the profile, the change in the main characteristic (Material Removal Rate – MRR process reaches tens of times. To stabilize the grinding process, it is recommended to control the spindle speed of the workpiece CNC grinding machine. Created software that allows to design the control program on the basis of mathematical model of the system. The determination of MRR is realized automatically in the simulation of the grinding process which uses the algorithm developed for solving problems in geometric interaction of the workpiece and the wheel. In forming the control program is possible takes into account the limitations on the maximum circumferential force of cutting, and the maximum allowable acceleration of the machine spindle. Practice has shown that full stabilization is not obtained, even though the performance is increased more than 2 times, while ensuring the quality of the surface. The developed block diagram of the grinding process can serve as a basis for further improvement in the solution of dynamic problems.

  3. Retificação da alumina com rebolo diamantado utilizando-se diferentes métodos de lubri-refrigeração Grinding of alumina with diamod wheel using different cooling methods

    Directory of Open Access Journals (Sweden)

    M. C. S Alves

    2010-06-01

    lack of reliability of ceramic components, because the variability on the mechanical strength caused by defects that can be impaired in the grinding process. The grinding of ceramics, as much as with steel grinding is performed generally with excess of cutting fluids (coolants. The use of coolants results in serious ecological, physiological and economic issues. Since last decade the public opinion, the market, the laws and regulations have pushed the industries to consider the environmental risks in the manufacturing process. Then, in order to evaluate alternatives to the conventional method of cooling and lubrication, it was studied the viability of the optimized technique, where the cutting fluid is applied to the same peripherical speed of the wheel, penetrating in the cutting zone with less turbulence. Also, it was verified the technique of Minimum Quantity of Lubricant (MQL, where a large amount of cutting fluid is replaced by an air compressed flow containing a small quantity of lubricant. The methods were compared through performance analysis of cutting forces, roughness and wheel (G ratio. As a conclusion is that MQL is not viable in ceramics grinding with the working conditions proposed. The results obtained with optimized technique are insufficient to state this technique presents better roughness and G-ratio values when compared to conventional method.

  4. Strength and residual stress of Mg-PSZ after grinding

    NARCIS (Netherlands)

    van den Berg, P.H.J.; With, de G.

    1993-01-01

    The influence of grinding with two grinding wheels, differing mainly in diamond-grain size, on the properties of MgO-partially stabilized ZrO2 ceramics (Mg-PSZ) was examd. The residual stress, the amt. of monoclinic zirconia, and the strength of the material were detd. From these measurements, depth

  5. THE DEVELOPMENT OF TECHNOLOGICAL METHODS OF LASER SURFACE TREATMENT OF HEAVILY LOADED PARTS WHEEL SET CARS

    Directory of Open Access Journals (Sweden)

    V. D. Sheliahin

    2009-06-01

    Full Text Available Possibility of application of processes of laser superficial processing for restoration and increase of a resource of operation of shafts and rims of wheels of railway cars is investigated. The influence of critical parametres of process on depth of a zone of laser influence and their interrelation with the structure obtained and hardness is determineed.

  6. Understanding the synergistic effect and the main factors influencing the enzymatic hydrolyzability of corn stover at low enzyme loading by hydrothermal and/or ultrafine grinding pretreatment.

    Science.gov (United States)

    Zhang, Haiyan; Li, Junbao; Huang, Guangqun; Yang, Zengling; Han, Lujia

    2018-05-26

    A thorough assessment of the microstructural changes and synergistic effects of hydrothermal and/or ultrafine grinding pretreatment on the subsequent enzymatic hydrolysis of corn stover was performed in this study. The mechanism of pretreatment was elucidated by characterizing the particle size, specific surface area (SSA), pore volume (PV), average pore size, cellulose crystallinity (CrI) and surface morphology of the pretreated samples. In addition, the underlying relationships between the structural parameters and final glucose yields were elucidated, and the relative significance of the factors influencing enzymatic hydrolyzability were assessed by principal component analysis (PCA). Hydrothermal pretreatment at a lower temperature (170 °C) combined with ultrafine grinding achieved a high glucose yield (80.36%) at a low enzyme loading (5 filter paper unit (FPU)/g substrate) which is favorable. The relative significance of structural parameters in enzymatic hydrolyzability was SSA > PV > average pore size > CrI/cellulose > particle size. PV and SSA exhibited logarithmic correlations with the final enzymatic hydrolysis yield. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Grinding of WC–Co hardmetals

    NARCIS (Netherlands)

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

    2001-01-01

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

  8. Surface topography of parallel grinding process for nonaxisymmetric aspheric lens

    International Nuclear Information System (INIS)

    Zhang Ningning; Wang Zhenzhong; Pan Ri; Wang Chunjin; Guo Yinbiao

    2012-01-01

    Workpiece surface profile, texture and roughness can be predicted by modeling the topography of wheel surface and modeling kinematics of grinding process, which compose an important part of precision grinding process theory. Parallel grinding technology is an important method for nonaxisymmetric aspheric lens machining, but there is few report on relevant simulation. In this paper, a simulation method based on parallel grinding for precision machining of aspheric lens is proposed. The method combines modeling the random surface of wheel and modeling the single grain track based on arc wheel contact points. Then, a mathematical algorithm for surface topography is proposed and applied in conditions of different machining parameters. The consistence between the results of simulation and test proves that the algorithm is correct and efficient. (authors)

  9. Modeling and simulation for fewer-axis grinding of complex surface

    Science.gov (United States)

    Li, Zhengjian; Peng, Xiaoqiang; Song, Ci

    2017-10-01

    As the basis of fewer-axis grinding of complex surface, the grinding mathematical model is of great importance. A mathematical model of the grinding wheel was established, and then coordinate and normal vector of the wheel profile could be calculated. Through normal vector matching at the cutter contact point and the coordinate system transformation, the grinding mathematical model was established to work out the coordinate of the cutter location point. Based on the model, interference analysis was simulated to find out the right position and posture of workpiece for grinding. Then positioning errors of the workpiece including the translation positioning error and the rotation positioning error were analyzed respectively, and the main locating datum was obtained. According to the analysis results, the grinding tool path was planned and generated to grind the complex surface, and good form accuracy was obtained. The grinding mathematical model is simple, feasible and can be widely applied.

  10. Ductile mode grinding of reaction-bonded silicon carbide mirrors.

    Science.gov (United States)

    Dong, Zhichao; Cheng, Haobo

    2017-09-10

    The demand for reaction-bonded silicon carbide (RB-SiC) mirrors has escalated recently with the rapid development of space optical remote sensors used in astronomy or Earth observation. However, RB-SiC is difficult to machine due to its high hardness. This study intends to perform ductile mode grinding to RB-SiC, which produces superior surface integrity and fewer subsurface damages, thus minimizing the workload of subsequent lapping and polishing. For this purpose, a modified theoretical model for grain depth of cut of grinding wheels is presented, which correlates various processing parameters and the material characteristics (i.e., elastic module) of a wheel's bonding matrix and workpiece. Ductile mode grinding can be achieved as the grain depth of cut of wheels decreases to be less than the critical cut depth of workpieces. The theoretical model gives a roadmap to optimize the grinding parameters for ductile mode grinding of RB-SiC and other ultra-hard brittle materials. Its feasibility was validated by experiments. With the optimized grinding parameters for RB-SiC, the ductile mode grinding produced highly specular surfaces (with roughness of ∼2.2-2.8  nm Ra), which means the material removal mechanism of RB-SiC is dominated by plastic deformation rather than brittle fracture. Contrast experiments were also conducted on fused silica, using the same grinding parameters; this produced only very rough surfaces, which further validated the feasibility of the proposed model.

  11. Research on operation mode of abrasive grain during grinding

    Science.gov (United States)

    Ivanova, T. N.; Dement’ev, V. B.; Nikitina, O. V.

    2018-03-01

    The processing of materials by cutting with an abrasive tool is carried out by means of thousands of grains bonded together as a single whole. The quality of the abrasive tool is defined by cutting properties of abrasive grains and depends on features of spreading the temperature field in time and in the abrasive grain volume. Grains are exposed to heating and cooling during work. It leads to undesired effects such as a decrease of durability of grain retention in the binder, hardness, intensification of diffusion and oxidation processes between the binder and the grain, the occurrence of considerable temperature stresses in the grain itself. The obtained equation which allows calculation of temperature field of grain for one rotation of grinding wheel shows that the temperature of the wheel depends on grinding modes and thermophysical properties of abrasive material. Thus, as the time of contact of grain with processed material increases, the temperature in the cutting area rises. As thermophysical properties increase, the temperature in cutting area decreases. Thermal working conditions are determined to be different from each other depending on contact time of the grain and the material. For example, in case of creep-feed grinding, the peak value of temperature is higher than during multistep grinding; the depth of expansion is greater. While the speed of the thermal process in creep-feed grinding is 2-3 times lower than in multistep grinding, the gradient reduces 3-4 times. The analysis of machining methods shows that creep-feed grinding ensures greater depth of grain heating, a smaller heating rate and a reduced velocity gradient. It causes a decrease of probable allotropic modifications and prevents from occurring of heat strokes - cracking of grains due to high temperature falls. Consequently, it is necessary to employ creep-feed grinding to increase the efficiency of abrasive tool employing. Three operation modes of grinding wheel including blunting, full

  12. Apparatus for feeding nuclear fuel pellets to a loading tray

    International Nuclear Information System (INIS)

    Huggins, T.B.

    1979-01-01

    Apparatus for feeding nuclear fuel pellets at a uniform predetermined rate between pellet centering and grinding apparatus and a tray for loading pellets into nuclear fuel rod. Pellets discharged from the grinding apparatus are conveyed by a belt to a drive wheel forcing the pellets in engagement with the belt. The pellets under the drive wheel are capable of pushing a line of about 36 pellets onto a pellet dumping mechanism. As the dumping mechanism is actuated to dump the pellets on to a loading tray, the pellets moving toward the mechanism are stopped and the drive wheel is simultaneously lifted off the pellets until the pellet dumping process is completed. (U.K.)

  13. Load theory behind the wheel: an experimental application of a cognitive model to simulated driving

    OpenAIRE

    Murphy, Gillian

    2017-01-01

    Load Theory is a prominent model of selective attention first proposed over twenty years ago. Load Theory is supported by a great many experimental and neuroimaging studies. There is however, little evidence that Load Theory can be applied to real world attention, though it has great practical potential. Driving, as an everyday task where failures of attention can have profound consequences, stands to benefit from the understanding of selective attention that Load Theory provides. The aim of ...

  14. Technological support of tool wear resistant qualities and cost saving of process of planetary grinding of flat parts

    Science.gov (United States)

    Ivanova, T. N.; Lyupa, D. C.; Revenko, N. F.; Berkutova, T. A.; Silivanova, O. A.

    2018-03-01

    A lot of factors varied in time lead to instability of the grinding process. Besides, the method of grinding influences significantly the productivity and quality of processing. In this regard a creation of processes of intensive defect-free grinding on the basis of new constructive and technology solutions represents the scientific problem which is of great importance. One of such solutions is application of planetary face grinding which allows simultaneously changing the kinematics of movement, implementing discontinuous grinding. The distinctive features of such grinding are decreasing the heat release rate in a contact zone; ensuring intermittence of the process with a solid grinding wheel; reverse grinding; cutting by different edges of an abrasive grain; stabilization of working parameters of a grinding wheel; ensuring work of a grinding wheel in a self-sharpening mode. The design of the planetary grinding tool was developed for plane surface processing for implementation of the specified distinctive features of planetary grinding. The kinematics of shaping a surface by flat face diamond grinding has been investigated; manufacturing capabilities of planetary face grinding have been revealed, and ways of improvement of quality and productivity have been offered. The algorithm and the program to define the motion path of a grain depending on the given set of grinding factors were received. Optimization of the process of face diamond grinding using the planetary grinding device has been confirmed with the developed program and techniques to choose cutting conditions of planetary grinding and characteristics of grinding wheels for processing different materials. While studying the process of planetary grinding, special attention was paid to the research how processing conditions influence microgeometry of the processed surface made of steel 4X5M (Russian State Standard (GOST)). As a result of the executed research, it was established that surface roughness

  15. Towards High Productivity in Precision Grinding

    Directory of Open Access Journals (Sweden)

    W. Brian Rowe

    2018-04-01

    Full Text Available Over the last century, substantial advances have been made, based on improved understanding of the requirements of grinding processes, machines, control systems, materials, abrasives, wheel preparation, coolants, lubricants, and coolant delivery. This paper reviews a selection of areas in which the application of scientific principles and engineering ingenuity has led to the development of new grinding processes, abrasives, tools, machines, and systems. Topics feature a selection of areas where relationships between scientific principles and new techniques are yielding improved productivity and better quality. These examples point towards further advances that can fruitfully be pursued. Applications in modern grinding technology range from high-precision kinematics for grinding very large lenses and reflectors through to medium size grinding machine processes and further down to grinding very small components used in micro electro-mechanical systems (MEMS devices. The importance of material issues is emphasized for the range of conventional engineering steels, through to aerospace materials, ceramics, and composites. It is suggested that future advances in productivity will include the wider application of artificial intelligence and robotics to improve precision, process efficiency, and features required to integrate grinding processes into wider manufacturing systems.

  16. Recovery tread wheel pairs of machining

    Directory of Open Access Journals (Sweden)

    Igor IVANOV

    2013-01-01

    Full Text Available The basic methods of resurfacing wheels are determined and analised. It’sshown that for raising resource of used wheels and decreasing requirements of railwaytransport for new wheels it’s reasonable to use methods of recovering not only geometricparameters of rim, but also its mechanical properties. It’s marked that use of infeedprofile high-speed grinding (VPVSh enables to intensify significantly process ofmechanical treatment of wheel rim profile both when its resurfacing in service and whenmanufacturing new wheel.

  17. A dynamic model of cylindrical plunge grinding process for chatter phenomena investigation

    Directory of Open Access Journals (Sweden)

    Lajmert Paweł

    2018-01-01

    Full Text Available In the paper, chatter vibrations in the cylindrical plunge grinding process are investigated. An improved model of the grinding process was developed which is able to simulate self-excited vibrations due to a regenerative effect on the workpiece and the grinding wheel surface. The model includes a finite-element model of the workpiece, two degrees of freedom model of the grinding wheel headstock and a model of wheel-workpiece geometrical interferences. The model allows to studying the influence of different factors, i.e. workpiece and machine parameters as well as grinding conditions on the stability limit and a chatter vibration growth rate. At the end, simulation results are shown and compared with exemplified real grinding results.

  18. Workpiece Temperature Variations During Flat Peripheral Grinding

    Science.gov (United States)

    Smirnov, Vitalii A.; Repko, Aleksandr V.

    2018-06-01

    The paper presents the results of researches of temperature variations during flat peripheral grinding. It is shown that the temperature variations of the workpiece can reach 25...30% of the average values, which can lead to some thermal defects. A nonlinear two-dimensional thermophysical grinding model is suggested. It takes into account local changes in the cutting conditions: the fluctuation of the cut layer and the cutting force, the thermal impact of the cutting grains, and the presence of surface cavities in the intermittent wheel. For the numerical solution of the problem, the method of finite differences is adapted. Researches of the method stability and convergence are made, taking into account the specific nature of the problem. A high accuracy of the approximation of the boundary conditions and the nonlinear heat equation is provided. An experimental verification of the proposed thermophysical model was carried out with the use of installation for simultaneous measurement of the grinding force and temperature. It is shown that the discrepancy between the theoretical and experimental values of the grinding temperature does not exceed 5%. The proposed thermophysical model makes it possible to predict with high accuracy the temperature variations during grinding by the wheel periphery.

  19. Precision grinding of microarray lens molding die with 4-axes controlled microwheel

    Directory of Open Access Journals (Sweden)

    Yuji Yamamoto, Hirofumi Suzuki, Takashi Onishi1, Tadashi Okino and Toshimichi Moriwaki

    2007-01-01

    Full Text Available This paper deals with precision grinding of microarray lens (fly eye molding die by using a resinoid bonded diamond wheel. An ultra-precision grinding system of microarray lens molding die and new truing method of resinoid bonded diamond wheel were developed. In this system, a grinding wheel was four-dimensionally controlled with 1 nm resolution by linear scale feedback system and scanned on the workpiece surface. New truing method by using a vanadium alloy tool was developed and its performance was obtained with high preciseness and low wheel wear. Finally, the microarray lens molding dies of fine grain tungsten carbide (WC was tested with the resinoid bonded diamond wheel to evaluate grinding performance.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-03-01

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

  1. Tool grinding machine

    Science.gov (United States)

    Dial, Sr., Charles E.

    1980-01-01

    The present invention relates to an improved tool grinding mechanism for grinding single point diamond cutting tools to precise roundness and radius specifications. The present invention utilizes a tool holder which is longitudinally displaced with respect to the remainder of the grinding system due to contact of the tool with the grinding surface with this displacement being monitored so that any variation in the grinding of the cutting surface such as caused by crystal orientation or tool thickness may be compensated for during the grinding operation to assure the attainment of the desired cutting tool face specifications.

  2. Improved tool grinding machine

    Science.gov (United States)

    Dial, C.E. Sr.

    The present invention relates to an improved tool grinding mechanism for grinding single point diamond cutting tools to precise roundness and radius specifications. The present invention utilizes a tool holder which is longitudinally displaced with respect to the remainder of the grinding system due to contact of the tool with the grinding surface with this displacement being monitored so that any variation in the grinding of the cutting surface such as caused by crystal orientation or tool thicknesses may be compensated for during the grinding operation to assure the attainment of the desired cutting tool face specifications.

  3. Study on design of light-weight super-abrasive wheel

    Science.gov (United States)

    Nohara, K.; Yanagihara, K.; Ogawa, M.

    2018-01-01

    Fixed-abrasive tool, also called a grinding wheel, is produced by furnacing abrasive compound which contains abrasive grains and binding powder such as vitrified materials or resins. Fixed-abrasive tool is installed on spindle of grinding machine. And it is given 1,800-2,000 min-1 of spindle rotation for the usage. The centrifugal fracture of the compound of fixed- abrasive tool is one of the careful respects in designing. In recent years, however, super-abrasive wheel as a fixed-abrasive tool has been developed and applied widely. One of the most characteristic respects is that metal is applied for the body of grinding-wheel. The strength to hold abrasive grain and the rigidity of wheel become stronger than those of general grinding wheel, also the lifespan of fixed-abrasive tool becomes longer. The weight of fixed-abrasive tool, however, becomes heavier. Therefore, when the super-abrasive wheel is used, the power consumption of spindle motor becomes larger. It also becomes difficult for the grinding-wheel to respond to sudden acceleration or deceleration. Thus, in order to reduce power consumption in grinding and to obtain quicker frequency response of super-abrasive wheel, the new wheel design is proposed. The design accomplishes 46% weight reduction. Acceleration that is one second quicker than that of conventional grinding wheel is obtained.

  4. Grinding Method and Error Analysis of Eccentric Shaft Parts

    Science.gov (United States)

    Wang, Zhiming; Han, Qiushi; Li, Qiguang; Peng, Baoying; Li, Weihua

    2017-12-01

    RV reducer and various mechanical transmission parts are widely used in eccentric shaft parts, The demand of precision grinding technology for eccentric shaft parts now, In this paper, the model of X-C linkage relation of eccentric shaft grinding is studied; By inversion method, the contour curve of the wheel envelope is deduced, and the distance from the center of eccentric circle is constant. The simulation software of eccentric shaft grinding is developed, the correctness of the model is proved, the influence of the X-axis feed error, the C-axis feed error and the wheel radius error on the grinding process is analyzed, and the corresponding error calculation model is proposed. The simulation analysis is carried out to provide the basis for the contour error compensation.

  5. ANFIS Modeling of the Surface Roughness in Grinding Process

    OpenAIRE

    H. Baseri; G. Alinejad

    2011-01-01

    The objective of this study is to design an adaptive neuro-fuzzy inference system (ANFIS) for estimation of surface roughness in grinding process. The Used data have been generated from experimental observations when the wheel has been dressed using a rotary diamond disc dresser. The input parameters of model are dressing speed ratio, dressing depth and dresser cross-feed rate and output parameter is surface roughness. In the experimental procedure the grinding conditions...

  6. Effect of a redesigned two-wheeled container for refuse collecting on mechanical loading of low back and shoulders

    NARCIS (Netherlands)

    Kuijer, P. Paul F. M.; Hoozemans, Marco J. M.; Kingma, Idsart; van Dieën, Jaap H.; de Vries, Wiebe H. K.; Veeger, Dirk Jan; van der Beek, Allard J.; Visser, Bart; Frings-Dresen, Monique H. W.

    2003-01-01

    The objective of this study was to compare the mechanical and perceived workload when working with a redesigned two-wheeled container and working with a standard two-wheeled container for refuse collecting. The three changes in the design of the container were a displacement of the position of the

  7. Analysis of the Dynamic Wheel Loads in Railway Transition Zones Considering the Moisture Condition of the Ballast and Subballast

    Directory of Open Access Journals (Sweden)

    Haoyu Wang

    2017-11-01

    Full Text Available Transition zones in railway tracks are the locations with considerable changes in vertical support structures, e.g., near bridges. Due to possible water flow constrictions in transition zone structures, there is frequently an increased moisture level in the ballast/subballast layers, which is a potential source of track degradation. This paper presents results of the moisture condition measured in three transition zones using ground penetrating radar, where the ballast/subballast are analyzed. The relationship between the moisture condition and track degradation in the transition zones is studied by comparing it to the longitudinal track level that is measured by the track inspection coaches. A strong connection is found between the high moisture condition and track degradation in the transition zones. The dynamic behavior of the transition zones with high moisture condition is analyzed using the Finite Element method. Differential stiffness and settlement are taken into consideration in the transition zone model, which is also coupled with a vehicle. The ballast/subballast layers are modelled as solid elements. Increased moisture conditions are considered as a reduction of elastic modulus, according to laboratory findings. Results show that high moisture leads to an increase of dynamic wheel loads in the transition zone, which explains the connection and confirms that the high moisture condition is a source of transition zone problems.

  8. Development of Diamond-like Carbon Fibre Wheel

    Institute of Scientific and Technical Information of China (English)

    魏源迁; 山口勝美; 洞口巌; 竹内雅之

    2004-01-01

    A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned normally to the grinding wheel surface by laminating Al sheets together with DLC fibres. In this paper, the formation process of DLC fibres and the fabrication process of a DLC fibre wheel were investigated. Many grinding experiments were also carried out on a precision NC plane milling machine using a newly developed DLC wheel. Grinding of specimens of silicon wafers, optical glasses, quartz, granites and hardened die steel SKD11 demonstrated the capabilities of nanometer surface finish. A smooth surface with a roughness value of Ra2.5nm (Ry26nm) was achieved.

  9. Conduit grinding apparatus

    Science.gov (United States)

    Nachbar, Henry D.; Korytkowski, Alfred S.

    1991-01-01

    A grinding apparatus for grinding the interior portion of a valve stem receiving area of a valve. The apparatus comprises a faceplate, a plurality of cams mounted to an interior face of the faceplate, a locking bolt to lock the faceplate at a predetermined position on the valve, a movable grinder and a guide tube for positioning an optical viewer proximate the area to be grinded. The apparatus can either be rotated about the valve for grinding an area of the inner diameter of a valve stem receiving area or locked at a predetermined position to grind a specific point in the receiving area.

  10. Limpeza da superfície de corte de rebolos por um sistema de ar comprimido na retificação cilíndrica externa de mergulho de materiais cerâmicos refrigerados com a técnica da mínima quantidade de lubrificante (MQL Grinding wheel surface cleaning using a compressed air system, in external plunge grinding of ceramics using the minimum quantity lubricant (MQL technique

    Directory of Open Access Journals (Sweden)

    E. C. Bianchi

    2012-06-01

    to diminish the amounts applied, due to some problems it may cause. The cost of the final product enhances considerably with the application of cutting fluids; they are environmentally hazardous substances, and the cause of many illnesses to the people involved. In this case, industries, universities and research centers are prompted to research alternative methods which are less harmful to the environment. Between these arises the minimum quantity lubricant (MQL technique, however having also its disadvantages, like the formation of a grout on wheel surface, which generates higher surface roughness on the workpiece. Aiming to minimize the problems concerning this grout, compressed air jets can be applied in order to clean the abrasive tool, which is the subject of the present work. This study aims to analyze some output variables of the external plunge grinding as surface roughness and roundness errors. Using the obtained results, it is intended to study MQL technique, aiming its improvement through the surface cleaning of the grinding wheel by compressed air jets.

  11. Analysis of grinding of superalloys and ceramics for off-line process optimization

    Science.gov (United States)

    Sathyanarayanan, G.

    The present study has compared the performances of resinoid, vitrified, and electroplated CBN wheels in creep feed grinding of M42 and D2 tool steels. Responses such as a specific energy, normal and tangential forces, and surface roughness were used as measures of performance. It was found that creep feed grinding with resinoid, vitrified, and electroplated CBN wheels has its own advantages, but no single wheel could provide good finish, lower specific energy, and high material removal rates simultaneously. To optimize the CBN grinding with different bonded wheels, a Multiple Criteria Decision Making (MCDM) methodology was used. Creep feed grinding of superalloys, Ti-6Al-4V and Inconel 718, has been modeled by utilizing neural networks to optimize the grinding process. A parallel effort was directed at creep feed grinding of alumina ceramics with diamond wheels to investigate the influence of process variables on responses based on experimental results and statistical analysis. The conflicting influence of variables was observed. This led to the formulation of ceramic grinding process as a multi-objective nonlinear mixed integer problem.

  12. Controlled wear of vitrified abrasive materials for precision grinding ...

    Indian Academy of Sciences (India)

    The study of bonding hard materials such as aluminium oxide and cubic boron nitride (BN) and the nature of interfacial cohesion between these materials and glass is very important from the perspective of high precision grinding. Vitrified grinding wheels are typically used to remove large volumes of metal and to produce ...

  13. Nano finish grinding of brittle materials using electrolytic in-process ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Recent developments in grinding have opened up new avenues for finishing of hard and brittle materials with nano-surface finish, high tolerance and accuracy. Grinding with superabrasive wheels is an excellent way to produce ultraprecision surface finish. However, superabrasive diamond grits need ...

  14. A critical study of high efficiency deep grinding

    International Nuclear Information System (INIS)

    Johnstone, Iain

    2002-01-01

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

  15. modeling grinding modeling grinding processes as micro processes

    African Journals Online (AJOL)

    eobe

    industrial precision grinding processes are cylindrical, center less and ... Several model shave been proposed and used to study grinding ..... grinding force for the two cases were 9.07237N/mm ..... International Journal of Machine Tools &.

  16. Grinding of WC-Co hard-metals

    NARCIS (Netherlands)

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

    2001-01-01

    Morphol. of ground surface of WC-Co cermets with 10 and 20% Co was studied. A deformed and detached surface layer was found on top of the specimens after surface grinding with a diamond wheel. Etching the surface layer revealed WC grains in the subsurface of the machined specimens. Most of these

  17. Grinding Away Microfissures

    Science.gov (United States)

    Booth, Gary N.; Malinzak, R. Michael

    1990-01-01

    Treatment similar to dental polishing used to remove microfissures from metal parts without reworking adjacent surfaces. Any variety of abrasive tips attached to small motor used to grind spot treated. Configuration of grinding head must be compatible with configurations of motor and workpiece. Devised to eliminate spurious marks on welded parts.

  18. Multifunctional centrifugal grinding unit

    Science.gov (United States)

    Sevostyanov, V. S.; Uralskij, V. I.; Uralskij, A. V.; Sinitsa, E. V.

    2018-03-01

    The article presents scientific and engineering developments of multifunctional centrifugal grinding unit in which the selective effect of grinding bodies on the crushing material is realized, depending on its physical and mechanical characteristics and various schemes for organizing the technological process

  19. Mechanical load on the low back and shoulders during pushing and pulling of two-wheeled waste containers compared with lifting and carrying of bags and bins.

    Science.gov (United States)

    Schibye, B; Søgaard, K; Martinsen, D; Klausen, K

    2001-08-01

    Compare the mechanical load on the low back and shoulders during pushing and pulling a two-wheeled container with the load during lifting and carrying the same amount of waste. Only little is known about risk factors and mechanical loads during push/pull operations. A complete 2(3) factor push/pull experiment. A two-wheeled container with 25 or 50 kg was pushed in front of and pulled behind the body by seven waste collectors. Further, the same subjects lifted and carried a paper bag and a dustbin both loaded with 7 and 25 kg. All operations were video recorded and the push/pull force was measured by means of a three-dimensional force transducer. Peak Motus and Watbak software were used for digitising and calculation of torque at L4/L5 and the shoulder joints and compression and shear forces at L4/L5. During pushing and pulling the compression at L4/L5 is from 605 to 1445 N. The extension torque at L4/L5 produced by the push/pull force is counteracted by the forward leaning of the upper body. The shear force is below 202 N in all situations. The torque at the shoulders is between 1 and 38 Nm. In the present experiments the torques at the low back and the shoulders are low during pushing and pulling. No relation exists between the size of the external force and the torque at the low back and the shoulder. Pushing and pulling are common in many workplaces and have often replaced lifting and carrying situations. This has emphasised the need for more knowledge of the internal mechanical load on the body during these activities.

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

    Science.gov (United States)

    Aleksandrova, Irina

    2016-01-01

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

  1. Optimal handgrip height of four-wheeled walker on various road conditions to reduce muscular load for elderly users with steady walking.

    Science.gov (United States)

    Takanokura, Masato

    2010-03-22

    A four-wheeled walker is a valuable tool for assisting elderly persons with walking. The handgrip height is one of the most important factor determining the usefulness of the walker. However, the optimal handgrip height for elderly users has not been considered from a biomechanical viewpoint. In this study, the handgrip height was optimized by a two-dimensional mechanical model to reduce muscular loads in the lower body as well as in the upper body with various road conditions during steady walking. A critical height of the handgrip existed at 48% of the body height for the user regardless of gender and body dimension. A lower handgrip relieved muscular load for stooping users with a lower standing height. The stooping user pushed the handgrip strongly in the perpendicular direction by leaning the upper body on the walker. However, upright users with a higher standing height should use a four-wheeled walker with a higher handgrip for maintaining his or her upright posture. For downhill movement, the optimal handgrip height depended on the slope angle and the friction coefficient between the road and the wheels of the walker. On a low-friction downhill such as asphalt with a steeper slope angle, the user was required to maintain an erect trunk with a higher handgrip and to press on the handgrip strongly in the perpendicular direction. Movement on a low-friction road was easier for users on a flat road and an uphill road, but it compelled distinct effort from users when moving downhill. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  2. Analysis of process parameters in surface grinding using single objective Taguchi and multi-objective grey relational grade

    Directory of Open Access Journals (Sweden)

    Prashant J. Patil

    2016-09-01

    Full Text Available Close tolerance and good surface finish are achieved by means of grinding process. This study was carried out for multi-objective optimization of MQL grinding process parameters. Water based Al2O3 and CuO nanofluids of various concentrations are used as lubricant for MQL system. Grinding experiments were carried out on instrumented surface grinding machine. For experimentation purpose Taguchi's method was used. Important process parameters that affect the G ratio and surface finish in MQL grinding are depth of cut, type of lubricant, feed rate, grinding wheel speed, coolant flow rate, and nanoparticle size. Grinding performance was calculated by the measurement G ratio and surface finish. For improvement of grinding process a multi-objective process parameter optimization is performed by use of Taguchi based grey relational analysis. To identify most significant factor of process analysis of variance (ANOVA has been used.

  3. Bearing restoration by grinding

    Science.gov (United States)

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

    1976-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Zhang Jianhua

    2014-01-01

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

  5. Research of grinding process of gears with involute profile to increase its efficiency

    Science.gov (United States)

    Ivanova, T. N.; Korshunov, A. I.; Sannikov, I. N.; Tyukpiekov, V. N.

    2018-03-01

    Grinding as final processing exerts great influence on quality and accuracy of a surface layer of gears. Gear grinding is the most productive method of abrasive processing providing gears of 3 - 8 degrees of accuracy. However violation of the temperature condition of grinding leads to emergence of burns on the surfaces of gears. Therefore the research of the reasons generating defects and finding the ways of their elimination are relevant. The work presents the research of involute tooth profile grinding by wheels of different types with different ways to form a surface. For every way the movements of a tool and a workpiece in order to receive a contour of the tooth socket are simulated. The advantages and the shortcomings of the tooth grinding using form wheels in a grinding method and using dish, worm wheels in generating the grinding method are revealed. The experience of gear production shows that availability of burns in the certain part of a tooth profile is caused by features of the gear grinding process. Theoretical and experimental researches of the thermal phenomena of gear grinding with different configurations of spots in a contact zone and a trajectory of their movement are conducted. There are recommendations how to choose grinding modes, characteristics of abrasive tools taking into account a non-burnt condition of a working surface of a gear. The right choice of lubricating fluid and the way of its supply greatly affect the efficiency of the gear grinding process. It is established that lubricating fluid with special additives gives the best results to obtain desired roughness of a processed surface. The recommendations of effective fluids and their foreign analogs are made.

  6. The project and technical study on the track of vertical axis linkage abrasive belt grinding of turbine blade

    International Nuclear Information System (INIS)

    Ma Yujian; Tang Xiaoqi; Chen Jihong; Yang Jianzhong

    2010-01-01

    A method of CNC turbine blade profile abrasive belt grinding is introduced based on optimum grinding effect, where the direction of the axis of trolley wheel is consistent with that of minimum principal curvature on the contact point of turbine blade. And the cutter location path is determined, and then the NC code is derived from post-processing. A virtual machine model is built in VERICUT software to simulate actual grinding process and applied in practice, which yielded satisfactory results. (authors)

  7. Electrolytic in process dressing (ELID) applied to double side grinding of ceramic materials

    Science.gov (United States)

    Spanu, Cristian E.

    The objective of the present work is to design, optimize, and validate an electrolytic in-process dressing (ELID)-assisted double side grinding process for finishing advanced ceramic components. To attain this objective, an original ELID double side grinding system was designed, fabricated, and operated at Precision Micro-Machining Center at The University of Toledo, Ohio. The ELID technique was selected from among other options to assure the in-situ dressing of the metal-bonded superabrasive grinding wheel and to maintain its cutting ability throughout the operation, which is, otherwise, a challenging enterprise. Optimizing the ELID double side grinding process parameters is an important goal of the present study. To achieve this goal, a complex integrated model was developed and validated through extensive experimental testing. Four analytical computerized models were developed and integrated: (1) an improved kinematic model of double side grinding accounting for workpiece rotation, which is used to simulate the grinding trajectories; (2) a microscopic model of the interaction between a single diamond grit and the work surface, which is used to predict the volume of material removed; (3) a stochastic model for the topographical characterization of the superabrasive wheel, which leads to a new prediction method of depth of indentation; and (4) an electrolytic oxidation model, which explains the dynamics of the oxide layer. In order to validate the models and to confirm the optimized process, experimental tests were conducted under different conditions: with vitrified and metallic bond grinding wheels, with various average grain sizes of diamond grits, with different superabrasive concentrations, with different grinding fluids, with and without ELID assistance. Our findings show that an optimized ceramic double side grinding process using fine diamond grit is more efficient than lapping in producing very fine surfaces. The experiments confirmed the superiority of

  8. Method to evaluate stress and deformation of small-sized buried pipe induced by wheel loads. Shokokei maisetsukan no rinkaju ni okeru oryoku henkei hyokaho

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Y.; Kataoka, T.; Kokusho, T.; Yoshida, Y. (Central Research Institute of Electric Power Industry, Tokyo (Japan))

    1994-03-21

    In order to establish a practical method to evaluate safety of buried pipes, which were generally used as cable-protection pipes, at shallow depth and under vehicle loads, a series of experiments and analyses were performed. Based on the results, a simplified method to evaluate stress and deformation of the buried pipes in pavement were proposed. In the experiments, hard PVC pipes, light steel conduit pipes, and corrugated hard PE pipes in nominal diameters from 75 to 200 mm were applied as specimens for representative flexible pipes, and field load tests in actual size as well as laboratory load tests using soil vessels were carried out. The calculated results by the proposed method were compared to the experimental results, finding that the calculated values gave a satisfactory agreement with measured values which were obtained by the field tests. As a result, it was confirmed that the practical method to evaluate circumferential stresses at the top of pipes and flat-deflection ratios of small-sized buried Pipes induced by wheel loads under various conditions were presented. 20 refs., 17 figs., 6 tabs.

  9. Ultrasonic grinding of optical materials

    Science.gov (United States)

    Cahill, Michael; Bechtold, Michael; Fess, Edward; Stephan, Thomas; Bechtold, Rob

    2017-10-01

    Hard ceramic optical materials such as sapphire, ALON, Spinel, PCA, or Silicon Carbide can present a significant challenge in manufacturing precision optical components due to their tough mechanical properties. These are also the same mechanical properties that make them desirable materials when used in harsh environments. Slow processing speeds, premature tool wear, and poor surface quality are common results of the tough mechanical properties of these materials. Often, as a preparatory stage for polishing, the finish of the ground surface greatly influences the polishing process and the resulting finished product. To overcome these challenges, OptiPro Systems has developed an ultrasonic assisted grinding technology, OptiSonic, which has been designed for the precision optics and ceramics industry. OptiSonic utilizes a custom tool holder designed to produce oscillations, in microns of amplitude, in line with the rotating spindle. A software package, IntelliSonic, is integral to the function of this platform. IntelliSonic can automatically characterize tooling during setup to identify and select the ideal resonant peak which to operate at. Then, while grinding, IntelliSonic continuously adjusts the output frequency for optimal grinding efficiency while in contact with the part. This helps maintain a highly consistent process under changing load conditions for a more precise surface. Utilizing a variety of instruments, tests have proven to show a reduction in force between tool and part by up to 50%, while increasing the surface quality and reducing tool wear. This paper will present the challenges associated with these materials and solutions created to overcome them.

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

    Directory of Open Access Journals (Sweden)

    S. A. Voronov

    2015-01-01

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

  11. ANALYSIS OF FORMING TREAD WHEEL SETS

    Directory of Open Access Journals (Sweden)

    Igor IVANOV

    2017-09-01

    Full Text Available This paper shows the results of a theoretical study of profile high-speed grinding (PHSG for forming tread wheel sets during repair instead of turning and mold-milling. Significant disadvantages of these methods are low capacity to adapt to the tool and inhomogeneous structure of the wheel material. This leads to understated treatment regimens and difficulties in recovering wheel sets with thermal and mechanical defects. This study carried out modeling and analysis of emerging cutting forces. Proposed algorithms describe the random occurrence of the components of the cutting forces in the restoration profile of wheel sets with an inhomogeneous structure of the material. To identify the statistical features of randomly generated structures fractal dimension and the method of random additions were used. The multifractal spectrum formed is decomposed into monofractals by wavelet transform. The proposed method allows you to create the preconditions for controlling the parameters of the treatment process.

  12. THE INFLUENCE OF GRINDING CONDITIONS ON THE DISTRIBUTION OF RESIDUAL STRESS IN THE SURFACE LAYER OF 17crni6-6 STEEL AFTER CARBURIZING

    Directory of Open Access Journals (Sweden)

    Jacek Sawicki

    2017-06-01

    Full Text Available This paper presents the results of a study aimed at determining the residual stress which results from developing the surface layer by low-pressure and conventional carburizing and grinding of 17CrNi6-6 steel. A synergistic effect of thermochemical and abrasive treatment was examined on ring samples used to study residual stress by Davidenkov’s method. Samples were subjected to vacuum carburizing and conventional carburizing, which was followed by grinding with a 38A60K8V aloxite grinding wheel and a CBN grinding wheel - RNB80/63B75V. The following cutting fluids were used during the grinding process: oil emulsion 5%, supply rate ca. 20 l/min, Micro5000 oil supplied at the minimum quantity lubrication (MQL of ca. 25 ml/h, dry machining. The study determined the effect of the type of grinding wheel and the cooling and lubricating agent on the distribution of residual stress in the sur-face layer. The best effects of grinding with respect to the residual stress were achieved with flood cooling with oil emulsion and grinding with a CBN grinding wheel.

  13. Nitramine Drying & Fine Grinding Facility

    Data.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-01-01

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

  15. Grinding kinetics and equilibrium states

    Science.gov (United States)

    Opoczky, L.; Farnady, F.

    1984-01-01

    The temporary and permanent equilibrium occurring during the initial stage of cement grinding does not indicate the end of comminution, but rather an increased energy consumption during grinding. The constant dynamic equilibrium occurs after a long grinding period indicating the end of comminution for a given particle size. Grinding equilibrium curves can be constructed to show the stages of comminution and agglomeration for certain particle sizes.

  16. Experimental verification of nanoparticle jet minimum quantity lubrication effectiveness in grinding

    International Nuclear Information System (INIS)

    Jia, Dongzhou; Li, Changhe; Zhang, Dongkun; Zhang, Yanbin; Zhang, Xiaowei

    2014-01-01

    In our experiment, K-P36 precision numerical control surface grinder was used for dry grinding, minimum quantity lubrication (MQL) grinding, nanoparticle jet MQL grinding, and traditional flood grinding of hardened 45 steel. A three-dimensional dynamometer was used to measure grinding force in the experiment. In this research, experiments were conducted to measure and calculate specific tangential grinding force, frictional coefficient, and specific grinding energy, thus verifying the lubrication performance of nanoparticles in surface grinding. Findings present that compared with dry grinding, the specific tangential grinding force of MQL grinding, nanoparticle jet MQL grinding, and flood grinding decreased by 45.88, 62.34, and 69.33 %, respectively. Their frictional coefficient was reduced by 11.22, 29.21, and 32.18 %, and the specific grinding energy declined by 45.89, 62.34, and 69.45 %, respectively. Nanoparticle jet MQL presented ideal lubrication effectiveness, which was attributed to the friction oil film with strong antifriction and anti-wear features formed by nanoparticles on the grinding wheel/workpiece interface. Moreover, lubricating properties of nanoparticles of the same size (50 nm) but different types were verified through experimentation. In our experiment, ZrO 2 nanoparticles, polycrystal diamond (PCD) nanoparticles, and MoS 2 nanoparticles were used in the comparison of nanoparticle jet MQL grinding. The experimental results manifest that MoS 2 nanoparticles exhibited the optimal lubricating effectiveness, followed by PCD nanoparticles. Our research also integrated the properties of different nanoparticles to analyze the lubrication mechanisms of different nanoparticles. The experiment further verified the impact of nanoparticle concentration on the effectiveness of nanoparticle jet MQL in grinding. The experimental results demonstrate that when the nanoparticle mass fraction was 6 %, the minimum specific tangential grinding force

  17. Electro-chemical grinding

    Science.gov (United States)

    Feagans, P. L.

    1972-01-01

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

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

    Directory of Open Access Journals (Sweden)

    S. Prabhu

    2014-06-01

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

  19. A tri-generation system based on polymer electrolyte fuel cell and desiccant wheel – Part A: Fuel cell system modelling and partial load analysis

    International Nuclear Information System (INIS)

    Najafi, Behzad; De Antonellis, Stefano; Intini, Manuel; Zago, Matteo; Rinaldi, Fabio; Casalegno, Andrea

    2015-01-01

    Highlights: • A mathematical model for a PEMFC based cogeneration system is developed. • Developed model is validated using the available experimental data. • Performance of the plant at full load conditions is investigated. • Performance indices while applying two different modifications are determined. • System’s performance with and without modifications at partial loads is investigated. - Abstract: Polymer Electrolyte Membrane Fuel Cell (PEMFC) based systems have recently received increasing attention as a viable alternative for meeting the residential electrical and thermal demands. However, as the intermittent demand profiles of a building can only be addressed by a tri-generative unit which can operate at partial loads, the variation of performance of the system at partial loads might affect its corresponding potential benefits significantly. Nonetheless, no previous study has been carried out on assessing the performance of this type of tri-generative systems in such conditions. The present paper is the first of a two part study dedicated to the investigation of the performance of a tri-generative system in which a PEMFC based system is coupled with a desiccant wheel unit. This study is focused on evaluating the performance of the PEMFC subsystem while operating at partial loads. Accordingly, a detailed mathematical model of the fuel cell subsystem is first developed and validated using the experimental data obtained from the plant’s and the fuel cell stack’s manufacturer. Next, in order to increase the performance of the plant, two modifications have been proposed and the resulting performance at partial load have been determined. The obtained results demonstrate that applying both modifications results in increasing the electrical efficiency of the plant by 5.5%. It is also shown that, while operating at partial loads, the electrical efficiency of the plant does not significantly change; the fact which corresponds to the trade-off between

  20. Effect of liquid active media on grinding and scratching of solids

    International Nuclear Information System (INIS)

    Pertsov, N.V.; Danilova, F.B.; Babat, I.G.

    1975-01-01

    In the present paper the influence of various liquid active media on grinding of tungsten carbide, hard alloy T 15 K 6, oxide of aluminium A995 and other materials with diamond grinding wheels is investigated. A grinding device is described. The results of the investigations show that materials with metallic type of bonds are most effectively treated in the medium of liquid metals; for material with an ionic structure the active media are water and aqueous solutions of electrolytes. It is pointed out that liquid active media will diminish the specific work of dispergation by as much as one order of magnitude

  1. The influence of grinding oil viscosity on grinding heat and burn damage in creep-feed grinding{copyright}

    Energy Technology Data Exchange (ETDEWEB)

    Zhen-Change Liu [Shandong Univ. of Technology, Jinan (China); Abe, Satoshi; Noda, Masahiro [Yushiro Chemical Industry Co. Ltd., Kanagawa (Japan)

    1995-08-01

    Grinding oils are widely used in precision grinding, such as tool grinding, thread grinding and gear grinding, during which processes grinding burn is the most prevalent damage affecting the integrity of ground surface. This paper discusses the influence of oil viscosity on grinding heat and burn damage in creep-feed-grinding. Experimental results indicated that, under lighter grinding conditions, the effects of oil viscosity was not observed, but under heavy grinding conditions grinding burn occurred when using low viscosity oil. When the viscosity of the oil was increased, grinding heat and burn damage tended to be reduced. As the viscosity was increased to a certain level, grinding burn reduction, by further increasing the viscosity, became less while other problems such as much higher oil pump noise and reduced oil flow occurred. It is clear that a viscosity limit exists for given grinding conditions. 5 refs., 4 figs., 3 tabs.

  2. Multi Objective Optimization of Multi Wall Carbon Nanotube Based Nanogrinding Wheel Using Grey Relational and Regression Analysis

    Science.gov (United States)

    Sethuramalingam, Prabhu; Vinayagam, Babu Kupusamy

    2016-07-01

    Carbon nanotube mixed grinding wheel is used in the grinding process to analyze the surface characteristics of AISI D2 tool steel material. Till now no work has been carried out using carbon nanotube based grinding wheel. Carbon nanotube based grinding wheel has excellent thermal conductivity and good mechanical properties which are used to improve the surface finish of the workpiece. In the present study, the multi response optimization of process parameters like surface roughness and metal removal rate of grinding process of single wall carbon nanotube (CNT) in mixed cutting fluids is undertaken using orthogonal array with grey relational analysis. Experiments are performed with designated grinding conditions obtained using the L9 orthogonal array. Based on the results of the grey relational analysis, a set of optimum grinding parameters is obtained. Using the analysis of variance approach the significant machining parameters are found. Empirical model for the prediction of output parameters has been developed using regression analysis and the results are compared empirically, for conditions of with and without CNT grinding wheel in grinding process.

  3. Grind hardening process

    CERN Document Server

    Salonitis, Konstantinos

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, B.P.

    1995-08-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    Science.gov (United States)

    Olesen, C G; Larsen, B H; Andresen, E L; de Zee, M

    2015-01-01

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

  7. Grinding Inside A Toroidal Cavity

    Science.gov (United States)

    Mayer, Walter; Adams, James F.; Burley, Richard K.

    1987-01-01

    Weld lines ground smooth within about 0.001 in. Grinding tool for smoothing longitudinal weld lines inside toroidal cavity includes curved tunnel jig to guide grinding "mouse" along weld line. Curvature of tunnel jig matched to shape of toroid so grinding ball in mouse follows circular arc of correct radius as mouse is pushed along tunnel. Tool enables precise control of grindout shape, yet easy to use.

  8. Elevator wheel

    Energy Technology Data Exchange (ETDEWEB)

    Zhornik, V.I.; Cherkov, Ye.M.; Simonov, A.A.

    1982-01-01

    An elevator wheel is suggested for unloading a sunken product from a bath of a heavy-average separator including discs of a bucket with inner walls, and covering sheets hinged to the buckets. In order to improve the degree of dehydration of the removed product, the inner wall of each bucket is made of sheets installed in steps with gaps of one in relation to the other.

  9. Word wheels

    CERN Document Server

    Clark, Kathryn

    2013-01-01

    Targeting the specific problems learners have with language structure, these multi-sensory exercises appeal to all age groups including adults. Exercises use sight, sound and touch and are also suitable for English as an Additional Lanaguage and Basic Skills students.Word Wheels includes off-the-shelf resources including lesson plans and photocopiable worksheets, an interactive CD with practice exercises, and support material for the busy teacher or non-specialist staff, as well as homework activities.

  10. Task-specific noise exposure during manual concrete surface grinding in enclosed areas-influence of operation variables and dust control methods.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Ames, April L; Milz, Sheryl A; Akbar-Khanzadeh, Mahboubeh

    2013-01-01

    Noise exposure is a distinct hazard during hand-held concrete grinding activities, and its assessment is challenging because of the many variables involved. Noise dosimeters were used to examine the extent of personal noise exposure while concrete grinding was performed with a variety of grinder sizes, types, accessories, and available dust control methods. Noise monitoring was conducted in an enclosed area covering 52 task-specific grinding sessions lasting from 6 to 72 minutes. Noise levels, either in minute average noise level (Lavg, dBA) or in minute peak (dBC), during concrete grinding were significantly (P grinding cup wheel (blade) sizes of 4-inch (100 mm), 5-inch (125 mm) and 6-inch (150 mm), and surface orientation (horizontal, inclined). Overall, minute Lavg during grinding was 97.0 ± 3.3 (mean ± SD), ranging from 87.9 to 113. The levels of minute Lavg during uncontrolled grinding (98.9 ± 5.2) or wet-grinding (98.5 ± 2.7) were significantly higher than those during local exhaust ventilation (LEV) grinding (96.2 ± 2.8). A 6-inch grinding cup wheel generated significantly higher noise levels (98.7 ± 2.8) than 5-inch (96.3 ± 3.2) or 4-inch (95.3 ± 3.5) cup wheels. The minute peak noise levels (dBC) during grinding was 113 ± 5.2 ranging from 104 to 153. The minute peak noise levels during uncontrolled grinding (119 ± 10.2) were significantly higher than those during wet-grinding (115 ± 4.5) and LEV-grinding (112 ± 3.4). A 6-inch grinding cup wheel generated significantly higher minute peak noise levels (115 ± 5.3) than 5-inch (112 ± 4.5) or 4-inch (111 ± 5.4) cup wheels. Assuming an 8-hour work shift, the results indicated that noise exposure levels during concrete grinding in enclosed areas exceeded the recommended permissible exposure limits and workers should be protected by engineering control methods, safe work practices, and/or personal protective devices.

  11. Novel CNC Grinding Process Control for Nanometric Surface Roughness for Aspheric Space Optical Surfaces

    Directory of Open Access Journals (Sweden)

    Jeong-Yeol Han

    2004-06-01

    Full Text Available Optics fabrication process for precision space optical parts includes bound abrasive grinding, loose abrasive lapping and polishing. The traditional bound abrasive grinding with bronze bond cupped diamond wheel leaves the machine marks of about 20 μm rms in height and the subsurface damage of about 1 μm rms in height to be removed by subsequent loose abrasive lapping. We explored an efficient quantitative control of precision CNC grinding. The machining parameters such as grain size, work-piece rotation speed and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis. The effectiveness of such grinding prediction models was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment achieved the predictability down to ±20 nm in height and the surface roughness down to 36 nm in height. This study contributed to improvement of the process efficiency reaching directly the polishing and figuring process without the need for the loose abrasive lapping stage.

  12. Mechanism and experimental research on ultra-precision grinding of ferrite

    Science.gov (United States)

    Ban, Xinxing; Zhao, Huiying; Dong, Longchao; Zhu, Xueliang; Zhang, Chupeng; Gu, Yawen

    2017-02-01

    Ultra-precision grinding of ferrite is conducted to investigate the removal mechanism. Effect of the accuracy of machine tool key components on grinding surface quality is analyzed. The surface generation model of ferrite ultra-precision grinding machining is established. In order to reveal the surface formation mechanism of ferrite in the process of ultraprecision grinding, furthermore, the scientific and accurate of the calculation model are taken into account to verify the grinding surface roughness, which is proposed. Orthogonal experiment is designed using the high precision aerostatic turntable and aerostatic spindle for ferrite which is a typical hard brittle materials. Based on the experimental results, the influence factors and laws of ultra-precision grinding surface of ferrite are discussed through the analysis of the surface roughness. The results show that the quality of ferrite grinding surface is the optimal parameters, when the wheel speed of 20000r/mm, feed rate of 10mm/min, grinding depth of 0.005mm, and turntable rotary speed of 5r/min, the surface roughness Ra can up to 75nm.

  13. Assessment of forearm and plantar foot load in the elderly using a four-wheeled walker with armrest and the effect of armrest height.

    Science.gov (United States)

    Ko, Chang-Yong; Kim, Sol-Bi; Choi, Hyuk-Jae; Chang, Yunhee; Kang, Sungjae; Heo, Yoon; Ryu, Jeicheong; Kim, Gyoosuk; Mun, Museong

    2014-01-01

    Patients with hand and/or wrist pathology are recommended to have a four-wheeled walker with an arm rest (FWW-AR) rather than a standard walker or a standard four-wheeled walker (FWW). However, only a few quantitative studies have been performed to compare upper and lower extremity weight bearing. The aim of this study was to evaluate forearm and foot weight bearing using a FWW-AR and the effect of the armrest height. Eleven elderly women (mean age 80.1±5.3 years; mean height 148.5±4.0 cm; mean weight 51.2±9.0 kg) were enrolled. The subjects walked with an FWW-AR, with the elbow in either 90 degree (D90) or 130 degree (D130) flexion, for a distance of 10 m. Surface electromyographic signals were recorded for the upper, middle, and lower trapezius, anterior deltoid, and erector spinae muscles; walking velocity was measured with the subjects weight bearing on their feet and forearms while walking. Simultaneously, the maximum plantar and forearm loads during walking with an FWW-AR were measured. The normalized foot plantar loads were lower at D90 than at D130, while the normalized forearm load was higher at D90 than at D130 (all P<0.05; left foot, 7.9±0.1 N/kg versus 8.8±0.1 N/kg; right foot, 8.6±0.2 N/kg versus. 9.6±0.1 N/kg; left forearm, 1.8±0.5 N/kg versus 0.8±0.2 N/kg; and right forearm, 2.0±0.5 N/kg versus 1.0±0.2 N/kg, respectively). The surface electromyographic activity of the muscles involved in shoulder elevation and the walking velocity were both lower with the elbow at D90 than at D130 (all P<0.05; left upper trapezius, 98.7%±19.5% versus 132.6%±16.9%; right upper trapezius, 83.4%±10.6% versus 108.1%±10.5%; left anterior deltoid, 94.1%±12.8% versus 158.6%±40.4%; right anterior deltoid, 99.1%±15.0% versus 151.9%±19.4%; and velocity, 0.6±0.1 m/sec versus 0.7±0.1 m/sec, respectively). Weight bearing on the lower extremities is significantly reduced when the upper extremities are supported during walking with an FWW-AR. Furthermore, the

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

    Science.gov (United States)

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

    2013-06-01

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

  15. Precision Surface Grinding of Silicon Carbide

    Directory of Open Access Journals (Sweden)

    Mohamed Konneh

    2016-12-01

    Full Text Available Silicon carbide (SiC is well known for its excellent material properties, high durability, high wear resistance, light weight and extreme hardness. Among the engineering applications of this material, it is an excellent candidate for optic mirrors used in an Airbone Laser (ABL device. However, the low fracture toughness and extreme brittleness characteristics of SiC are predominant factors for its poor machinability. This paper presents surface grinding of SiC using diamond cup wheels to assess the performance of diamond grits with respect to the roughness produced on the machined surfaces and also the morphology of the ground work-piece. Resin bonded diamond cup wheels of grit sizes 46 µm, 76 µm and 107 µm; depth of cut of 10 µm, 20 µm and 30 µm; and feed rate of 2 mm/min, 12 mm/min and 22 mm/min were used during this machining investigation. It has been observed that the 76 grit performs better in terms of low surface roughness value and morphology.

  16. Grinding mechanism of zirconia toughened alumina

    International Nuclear Information System (INIS)

    Tsukuda, A.; Kondo, Y.; Yokota, K.

    1998-01-01

    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

  17. Fatigue limit of polycrystalline zirconium oxide ceramics: Effect of grinding and low-temperature aging.

    Science.gov (United States)

    Pereira, G K R; Silvestri, T; Amaral, M; Rippe, M P; Kleverlaan, C J; Valandro, L F

    2016-08-01

    The following study aimed to evaluate the effect of grinding and low-temperature aging on the fatigue limit of Y-TZP ceramics for frameworks and monolithic restorations. Disc specimens from each ceramic material, Lava Frame (3M ESPE) and Zirlux FC (Ivoclar Vivadent) were manufactured according to ISO:6872-2008 and assigned in accordance with two factors: (1) "surface treatment"-without treatment (as-sintered, Ctrl), grinding with coarse diamond bur (181µm; Grinding); and (2) "low-temperature aging (LTD)" - presence and absence. Grinding was performed using a contra-angle handpiece under constant water-cooling. LTD was simulated in an autoclave at 134°C under 2-bar pressure for 20h. Mean flexural fatigue limits (20,000 cycles) were determined under sinusoidal loading using stair case approach. For Lava ceramic, it was observed a statistical increase after grinding procedure and different behavior after LTD stimuli (Ctrl<Grinding; CtrlGrinding=Grinding Ltd); while for Zirlux, grinding and low-temperature aging promoted a statistical increase in the fatigue limit (Ctrl<Grinding; CtrlGrinding Ltd). An important increase was observed in m-phase content after both stimuli (grinding and LTD), although with different intensities. Additionally, fatigue test did not promote increase of m-phase content. Thus, tested grinding and low temperature aging did not damage the fatigue limit values significantly for both materials evaluated, even though those conditions promoted increase in m-phase. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Nanofluid as coolant for grinding process: An overview

    Science.gov (United States)

    Kananathan, J.; Samykano, M.; Sudhakar, K.; Subramaniam, S. R.; Selavamani, S. K.; Manoj Kumar, Nallapaneni; Keng, Ngui Wai; Kadirgama, K.; Hamzah, W. A. W.; Harun, W. S. W.

    2018-04-01

    This paper reviews the recent progress and applications of nanoparticles in lubricants as a coolant (cutting fluid) for grinding process. The role of grinding machining in manufacturing and the importance of lubrication fluids during material removal are discussed. In grinding process, coolants are used to improve the surface finish, wheel wear, flush the chips and to reduce the work-piece thermal deformation. The conventional cooling technique, i.e., flood cooling delivers a large amount of fluid and mist which hazardous to the environment and humans. Industries are actively looking for possible ways to reduce the volume of coolants used in metal removing operations due to the economical and ecological impacts. Thus as an alternative, an advanced cooling technique known as Minimum Quantity Lubrication (MQL) has been introduced to the enhance the surface finish, minimize the cost, to reduce the environmental impacts and to reduce the metal cutting fluid consumptions. Nanofluid is a new-fangled class of fluids engineered by dispersing nanometre-size solid particles into base fluids such as water, lubrication oils to further improve the properties of the lubricant or coolant. In addition to advanced cooling technique review, this paper also reviews the application of various nanoparticles and their performance in grinding operations. The performance of nanoparticles related to the cutting forces, surface finish, tool wear, and temperature at the cutting zone are briefly reviewed. The study reveals that the excellent properties of the nanofluid can be beneficial in cooling and lubricating application in the manufacturing process.

  19. Sensor-Based Inspection of the Formation Accuracy in Ultra-Precision Grinding (UPG) of Aspheric Surface Considering the Chatter Vibration

    Science.gov (United States)

    Lei, Yao; Bai, Yue; Xu, Zhijun

    2018-06-01

    This paper proposes an experimental approach for monitoring and inspection of the formation accuracy in ultra-precision grinding (UPG) with respect to the chatter vibration. Two factors related to the grinding progress, the grinding speed of grinding wheel and spindle, and the oil pressure of the hydrostatic bearing are taken into account to determining the accuracy. In the meantime, a mathematical model of the radius deviation caused by the micro vibration is also established and applied in the experiments. The results show that the accuracy is sensitive to the vibration and the forming accuracy is much improved with proper processing parameters. It is found that the accuracy of aspheric surface can be less than 4 μm when the grinding speed is 1400 r/min and the wheel speed is 100 r/min with the oil pressure being 1.1 MPa.

  20. Sensor-Based Inspection of the Formation Accuracy in Ultra-Precision Grinding (UPG) of Aspheric Surface Considering the Chatter Vibration

    Science.gov (United States)

    Lei, Yao; Bai, Yue; Xu, Zhijun

    2018-03-01

    This paper proposes an experimental approach for monitoring and inspection of the formation accuracy in ultra-precision grinding (UPG) with respect to the chatter vibration. Two factors related to the grinding progress, the grinding speed of grinding wheel and spindle, and the oil pressure of the hydrostatic bearing are taken into account to determining the accuracy. In the meantime, a mathematical model of the radius deviation caused by the micro vibration is also established and applied in the experiments. The results show that the accuracy is sensitive to the vibration and the forming accuracy is much improved with proper processing parameters. It is found that the accuracy of aspheric surface can be less than 4 μm when the grinding speed is 1400 r/min and the wheel speed is 100 r/min with the oil pressure being 1.1 MPa.

  1. TECHNICAL NOTE: High-speed grinding using thin abrasive disks for microcomponents

    Science.gov (United States)

    Yeo, S. H.; Balon, S. A. P.

    2002-01-01

    This paper introduces the development of a high-speed grinding device for cylindrical grinding of microcomponents made of hard and brittle materials. The study made use of an ultraprecision diamond turning machine tool as a basic platform. The novelty of the device is based on the high-speed air bearing spindle with a thin grinding wheel, similar to the dicing technology for silicon wafer fabrication. The spindle attachment is inclined at an angle to the main spindle which holds the precision fixture mechanism via the vacuum chuck. Experiments have been conducted to verify the design and implementation of the grinding methodology. A feature size as small as 31 μm in diameter and average surface roughness of 98 nm were obtained in the experimental work. It is found that the work done is capable of manufacturing miniature components, such as microcylindrical stepped shafts.

  2. Biaxial wheel/hub test facility. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.; Grubisic, V. [eds.

    2000-07-01

    The 4{sup th} meeting aims to exchange the experience and knowledge of engineers during several presentations and discussions about new developments required for a reliable, time and cost reducing validation of the wheel/hub assembly. Tremendous development of the wheel performance, described by the ratio of the rated load (kg) versus the wheel weight (kg) had taken place during the last 5000 years. Starting from the ratio of 3 for wooden 2-piece-disc-wheels in Mesopotamia it needed nearly 1000 years to increase the ratio to approx 5 at light-weight spoke wheels for fighting carriages, found in the grave of king Tutenchamon in Egypt. Modern light alloy wheels of commercial vehicles reach values up to 160 kg/kg. Additionally the comlex design of the modern systems for cars and commercial vehicles comprising wheel, brake, hub, bearing, spindle and hub carrier, including different materials and their treatment, fasteners, press-fits, require an appropriate testing procedure. The variable loading conditions, caused by operational wheel forces, brake and torque moments including heating, may result in changing tolerances and press-fits during operation and consequently in different damage mechanisms. This can be simulated in the Biaxial Wheel Test Machine, whereby corresponding load programs are necessary. An overview about all biaxial test machines in usage at the end of 1999 is shown in the introduction. The total number is 17 for cars, 7 for commercial vehicles and 1 for trains. The six presentations of this meeting were consequently concentrated on: (a) recommendations for a standardization of load programs of the German Wheel Committee, (b) the simulation of brake and torque events and (c) the possibility for a numerical stress analyses and fatigue life assessment. (orig./AKF)

  3. Grinding Parameter Optimization of Ultrasound-Aided Electrolytic in Process Dressing for Finishing Nanocomposite Ceramics

    Directory of Open Access Journals (Sweden)

    Fan Chen

    2016-01-01

    Full Text Available In order to achieve the precision and efficient processing of nanocomposite ceramics, the ultrasound-aided electrolytic in process dressing method was proposed. But how to realize grinding parameter optimization, that is, the maximum processing efficiency, on the premise of the assurance of best workpiece quality is a problem that needs to be solved urgently. Firstly, this research investigated the influence of grinding parameters on material removal rate and critical ductile depth, and their mathematic models based on the existing models were developed to simulate the material removal process. Then, on the basis of parameter sensitivity analysis based on partial derivative, the sensitivity models of material removal rates on grinding parameter were established and computed quantitatively by MATLAB, and the key grinding parameter for optimal grinding process was found. Finally, the theoretical analyses were verified by experiments: the material removal rate increases with the increase of grinding parameters, including grinding depth (ap, axial feeding speed (fa, workpiece speed (Vw, and wheel speed (Vs; the parameter sensitivity of material removal rate was in a descending order as ap>fa>Vw>Vs; the most sensitive parameter (ap was optimized and it was found that the better machining result has been obtained when ap was about 3.73 μm.

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

    Science.gov (United States)

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

    2014-01-01

    In recent years, a large number of patents have been devoted to developing minimum quantity lubrication (MQL) grinding techniques that can significantly improve both environmentally conscious and energy saving and costeffective sustainable grinding fluid alternatives. Among them, one patent is about a controllable nano-fluids jet MQL grinding system based on electrostatic atomization. Using the principle of electrostatics, it can achieve the control of droplet transfer by charging the sprayed droplets. This system can improve the uniformity of the droplet spectrum, liquid deposition efficiency and effective utilization of liquid. It can also effectively control the movement patterns of the droplets, thereby reducing the pollution of the environment and providing better health protection for workers. Although researchers accomplished profound and systematic studies on MQL, especially on nano-particles jet MQL. It can solve the shortage of MQL in cooling performance, greatly improve the working environment, save energy and reduce costs to achieve a low-carbon manufacturing. The unique lubricating performance and tribological property of solid nano-particles form nano-particle shearing films at the grinding wheel/workpiece interface, which can enhance the lubricating performance of MQL grinding. Existing studies on MQL grinding equipments, however, cannot meet the needs of the technological development. Therefore, our research provided a general introduction of the latest patients and research progress of nanoparticles jet MQL grinding equipments presented by the research team from Qingdao Technological University.

  5. Effect of grinding conditions on the fatigue life of titanium 5Al-2.5Sn alloy

    Science.gov (United States)

    Rangaswamy, P.; Terutung, H.; Jeelani, S.

    1991-01-01

    An investigation into the effect of grinding conditions on the fatigue life of titanium 5Al-2.5Sn is presented. Damage to surface integrity and changes in the residual stresses distribution are studied to assess changes in fatigue life. A surface grinding machine, operating at speeds ranging from 2000 to 6000 fpm and using SiC wheels of grit sizes 60 and 120, was used to grind flat subsize specimens of 0.1-in. thickness. After grinding, the specimens were fatigued at a chosen stress and compared with the unadulterated material. A standard profilometer, a microhardness tester, and a scanning electron microscope were utilized to examine surface characteristics and measure roughness and hardness. Increased grinding speed in both wet and dry applications tended to decrease the fatigue life of the specimens. Fatigue life increased markedly at 2000 fpm under wet conditions, but then decreased at higher speeds. Grit size had no effect on the fatigue life.

  6. Simulation and experimental investigation of inner-jet electrochemical grinding of GH4169 alloy

    Directory of Open Access Journals (Sweden)

    Hansong LI

    2018-03-01

    Full Text Available GH4169 alloy is one of the most commonly used materials in aero engine turbine blades, but its machinability is poor because of its excellent strength at high temperatures. Electrochemical machining (ECM has become a common method for machining this alloy and other difficult-to-machine materials. Electrochemical grinding (ECG is a hybrid process combining ECM and conventional grinding. In this paper, investigations conducted on inner-jet ECG of GH4169 alloy are described. Two types of inner-jet ECG grinding wheels were used to machine a flat bottom surface. The machining process was simulated using COMSOL software, and machining gaps under different machining parameters were obtained. In addition, maximum feed rates and maximum material removal rates under different machining parameters were studied experimentally. The maximum sizes and the uniformity of the distributions of the gaps machined by the two grinding wheels were compared. The effects of different applied voltages on the machining results were also investigated. Keywords: Electrochemical grinding, GH4169 alloy, Inner-jet, Material removal rate, Maximum feed rate

  7. Techniques for chamfer and taper grinding of oxide fuel pellets (LWBR Development Program)

    International Nuclear Information System (INIS)

    Johnson, R.G.R.; Allison, J.W.

    1981-10-01

    Floor mounted centerless grinding machines were adapted for shaping the edges of cylindrical oxide fuel pellets for the Light Water Breeder Reactor (LWBR) by plunge grinding. Edge configurations consisted of chamfers, either 0.015 inch x 45 0 or 0.006 inch x 45 0 , or tapers 0.150 inch long x .0025 inch deep. Grinding was done by plunging the pellet against a shaped grinding wheel which ground both the diameter to the required size and shaped the edges of the pellet. Two plunges per pellet were required to complete the operation. Separate wheels were needed for grinding either a chamfer or a taper, the set up was adjustable to vary the size of the chamfer or taper as needed. The set up also had the flexibility to accommodate the multiple pellet lengths and diameters required by the LWBR design. Tight manufacturing tolerances in the chamfer and taper dimensions required the use of dimensional control charts and statistical sampling plans as process controls

  8. The response of a high-speed train wheel to a harmonic wheel-rail force

    International Nuclear Information System (INIS)

    Sheng, Xiaozhen; Liu, Yuxia; Zhou, Xin

    2016-01-01

    The maximum speed of China's high-speed trains currently is 300km/h and expected to increase to 350-400km/h. As a wheel travels along the rail at such a high speed, it is subject to a force rotating at the same speed along its periphery. This fast moving force contains not only the axle load component, but also many components of high frequencies generated from wheel-rail interactions. Rotation of the wheel also introduces centrifugal and gyroscopic effects. How the wheel responds is fundamental to many issues, including wheel-rail contact, traction, wear and noise. In this paper, by making use of its axial symmetry, a special finite element scheme is developed for responses of a train wheel subject to a vertical and harmonic wheel-rail force. This FE scheme only requires a 2D mesh over a cross-section containing the wheel axis but includes all the effects induced by wheel rotation. Nodal displacements, as a periodic function of the cross-section angle 6, can be decomposed, using Fourier series, into a number of components at different circumferential orders. The derived FE equation is solved for each circumferential order. The sum of responses at all circumferential orders gives the actual response of the wheel. (paper)

  9. Grinding in lead-zinc concentrator Sasa – choice between different grinding media

    OpenAIRE

    Krstev, Boris

    2004-01-01

    In this paper will be present result obtained from investigation in the grinding circuit of the lead-zinc concentrator Sasa,using differen grindng media: • Litzkhun-Niederwipper Forged Steel grinding balls; • GSI LUCCHINI Moly-Cop Forged Steel grinding balls; • Cast steel grinding balls from Ukraina and Bulgaria; In the same time will be shown comparation between obtained parameters using different grinding balls specially: • Capacity of the grinding mill; • Particle size; ...

  10. Determination of high-strength materials diamond grinding rational modes

    Science.gov (United States)

    Arkhipov, P. V.; Lobanov, D. V.; Rychkov, D. A.; Yanyushkin, A. S.

    2018-03-01

    The analysis of methods of high-strength materials abrasive processing is carried out. This method made it possible to determine the necessary directions and prospects for the development of shaping combined methods. The need to use metal bonded diamond abrasive tools in combination with a different kind of energy is noted to improve the processing efficiency and reduce the complexity of operations. The complex of experimental research on revealing the importance of mechanical and electrical components of cutting regimes, on the cutting ability of diamond tools, as well as the need to reduce the specific consumption of an abrasive wheel as one of the important economic indicators of the processing process is performed. It is established that combined diamond grinding with simultaneous continuous correction of the abrasive wheel contributes to an increase in the cutting ability of metal bonded diamond abrasive tools when processing high-strength materials by an average of 30% compared to diamond grinding. Particular recommendations on the designation of technological factors are developed depending on specific production problems.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    Combining torrefaction and grinding of biomass in one reactor may be an attractive fuel pretreatment process. A combined laboratory torrefaction and ball mill reactor has been constructed for studies of the influence of temperature and residence time on the product yields and particle size...... reductions of Danish wheat straw, spruce chips, and pine chips. On the basis of initial experiments, which evaluated the influence of reactor mass loading, gas flow, and grinding ball size and material, a standard experimental procedure was developed. The particle size reduction capability......, and ash composition, where straw has a higher alkali content. This and other studies indicate that the large difference in the alkali contents of the biomasses is the main cause for the observed difference in torrefaction characteristics. Experiments with separate particle heating and grinding showed...

  12. Fatigue Tests on Welded Joints Improved by Grinding

    DEFF Research Database (Denmark)

    Agerskov, Henning; Bjørnbak-Hansen, Jørgen; Olesen, John Forbes

    The present project is a part of an investigation on the fatigue life of the welded structure of large two-stroke diesel engines. Of special interest has been a study of the improvement in fatigue life, due to grinding of the weld toes. The test series carried through showed a significant increase...... without grinding to approx. 6.4 for the test series with grinding. In one of the test series (No. 7), the crack initiation in most tests moved from the weld toe to the non-ground surface between the ground areas at the weld toes, due to the grinding....... in fatigue life due to the grinding, ranging from a factor of approx. 2.8 to infinity, depending on the load level. With the limited number of tests carried out, S-N lines have not been determined. However, the results obtained indicate a change in slope of the S-N line from approx. 3.0 for the test series...

  13. Determination of rational parameters for process of grinding materials pre-crushed by pressure in ball mill

    Science.gov (United States)

    Romanovich, A. A.; Romanovich, L. G.; Chekhovskoy, E. I.

    2018-03-01

    The article presents the results of experimental studies on the grinding process of a clinker preliminarily ground in press roller mills in a ball mill equipped with energy exchange devices. The authors studied the influence of the coefficients of loading for grinding bodies of the first and second mill chambers, their lengths, angles of inclination, and the mutual location of energy exchange devices (the ellipse segment and the double-acting blade) on the output parameters of the grinding process (productivity, drive power consumption and specific energy consumption). It is clarified that the best results of the disaggregation and grinding process, judging by the minimum specific energy consumption in the grinding of clinker with an anisotropic texture after force deformation between the rolls of a press roller shredder, are achieved at a certain angle of ellipse segment inclination; the length of the first chamber and the coefficients of loading the chambers with grinding bodies.

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

    Science.gov (United States)

    Miho, Otoaki; Sato, Toru; Matsukubo, Takashi

    2015-01-01

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

  15. Wheel inspection system environment.

    Science.gov (United States)

    2008-11-18

    International Electronic Machines Corporation (IEM) has developed and is now marketing a state-of-the-art Wheel Inspection System Environment (WISE). WISE provides wheel profile and dimensional measurements, i.e. rim thickness, flange height, flange ...

  16. The Influence of Wheel/Rail Contact Conditions on the Microstructure and Hardness of Railway Wheels

    Directory of Open Access Journals (Sweden)

    Paul Molyneux-Berry

    2014-01-01

    Full Text Available The susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material. These are influenced by the steel composition, wheel manufacturing process, and thermal and mechanical loading during operation. The in-service properties therefore vary with depth below the surface and with position across the wheel tread. This paper discusses the stress history at the wheel/rail contact (derived from dynamic simulations and observed variations in hardness and microstructure. It is shown that the hardness of an “in-service” wheel rim varies significantly, with three distinct effects. The underlying hardness trend with depth can be related to microstructural changes during manufacturing (proeutectoid ferrite fraction and pearlite lamellae spacing. The near-surface layer exhibits plastic flow and microstructural shear, especially in regions which experience high tangential forces when curving, with consequentially higher hardness values. Between 1 mm and 7 mm depth, the wheel/rail contacts cause stresses exceeding the material yield stress, leading to work hardening, without a macroscopic change in microstructure. These changes in material properties through the depth of the wheel rim would tend to increase the likelihood of crack initiation on wheels toward the end of their life. This correlates with observations from several train fleets.

  17. Characterisation and management of concrete grinding residuals.

    Science.gov (United States)

    Kluge, Matt; Gupta, Nautasha; Watts, Ben; Chadik, Paul A; Ferraro, Christopher; Townsend, Timothy G

    2018-02-01

    Concrete grinding residue is the waste product resulting from the grinding, cutting, and resurfacing of concrete pavement. Potential beneficial applications for concrete grinding residue include use as a soil amendment and as a construction material, including as an additive to Portland cement concrete. Concrete grinding residue exhibits a high pH, and though not hazardous, it is sufficiently elevated that precautions need to be taken around aquatic ecosystems. Best management practices and state regulations focus on reducing the impact on such aquatic environment. Heavy metals are present in concrete grinding residue, but concentrations are of the same magnitude as typically recycled concrete residuals. The chemical composition of concrete grinding residue makes it a useful product for some soil amendment purposes at appropriate land application rates. The presence of unreacted concrete in concrete grinding residue was examined for potential use as partial replacement of cement in new concrete. Testing of Florida concrete grinding residue revealed no dramatic reactivity or improvement in mortar strength.

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

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Bruxism (Teeth Grinding or Clenching) KidsHealth / For Parents / Bruxism ( ... called bruxism , which is common in kids. About Bruxism Bruxism is the medical term for the grinding ...

  19. Sparking-out optimization while surface grinding aluminum alloy 1933T2 parts using fuzzy logic

    Science.gov (United States)

    Soler, Ya I.; Salov, V. M.; Kien Nguyen, Chi

    2018-03-01

    The article presents the results of a search for optimal sparing-out strokes when surface grinding aluminum parts by high-porous wheels Norton of black silicon carbide 37C80K12VP using fuzzy logic. The topography of grinded surface is evaluated according to the following parameters: roughness – Ra, Rmax, Sm; indicators of flatness deviation – EFEmax, EFEa, EFEq; microhardness HV, each of these parameters is represented by two measures of position and dispersion. The simulation results of fuzzy logic in the Matlab medium establish that during the grinding of alloy 1933T2, the best integral performance evaluation of sparking-out was given to two double-strokes (d=0.827) and the worst – to three ones (d=0.405).

  20. Steel grinding media in production use

    International Nuclear Information System (INIS)

    Nass, D.E.

    1975-01-01

    This paper reviews the types of steel being used for grinding rods and balls by the mining industry in U. S. and Canada. Results of a Dec. 1973 grinding media survey of U. S. and Canadian mills are summarized. Common alloying elements (C, Mn, Cr, Mo, Cu, etc.) are discussed. Grinding balls and rods are discussed separately; wear tests using irradiated balls are described. Finally, defects in grinding media are discussed

  1. Ceramic-bonded abrasive grinding tools

    Science.gov (United States)

    Holcombe, Jr., Cressie E.; Gorin, Andrew H.; Seals, Roland D.

    1994-01-01

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

  2. Ceramic-bonded abrasive grinding tools

    Science.gov (United States)

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

    1994-11-22

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

  3. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

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

    1980-01-01

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

  4. Torsional Moment Measurement on Bucket Wheel Shaft of Giant Machine

    Directory of Open Access Journals (Sweden)

    Jiří FRIES

    2011-06-01

    Full Text Available Bucket wheel loading at the present time (torsional moment on wheel shaft, peripheral cutting force is determined from electromotor incoming power or reaction force measured on gearbox hinge. Both methods together are weighted by steel construction absorption of driving units and by inertial forces of motor rotating parts. In the article is described direct method of the torsional moment measurement, which eliminates mentioned unfavourable impacts except absorption of steel construction of bucket wheel itself.

  5. Phenomena of Foamed Concrete under Rolling of Aircraft Wheels

    Science.gov (United States)

    Jiang, Chun-shui; Yao, Hong-yu; Xiao, Xian-bo; Kong, Xiang-jun; Shi, Ya-jie

    2014-04-01

    Engineered Material Arresting System (EMAS) is an effective technique to reduce hazards associated with aircraft overrunning runway. In order to ascertain phenomena of the foamed concrete used for EMAS under rolling of aircraft wheel, a specially designed experimental setup was built which employed Boeing 737 aircraft wheels bearing actual vertical loads to roll through the foamed concrete. A number of experiments were conducted upon this setup. It is discovered that the wheel rolls the concrete in a pure rolling manner and crushes the concrete downwards, instead of crushing it forward, as long as the concrete is not higher than the wheel axle. The concrete is compressed into powder in-situ by the wheel and then is brought to bottom of the wheel. The powder under the wheel is loose and thus is not able to sustain wheel braking. It is also found that after being rolled by the wheel the concrete exhibits either of two states, i.e. either 'crushed through' whole thickness of the concrete or 'crushed halfway', depending on combination of strength of the concrete, thickness of the concrete, vertical load the wheel carries, tire dimension and tire pressure. A new EMAS design concept is developed that if an EMAS design results in the 'crushed through' state for the main gears while the 'crushed halfway' state for the nose gear, the arresting bed would be optimal to accommodate the large difference in strength between the nose gear and the main gear of an aircraft.

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

    Directory of Open Access Journals (Sweden)

    Ding Wenfeng

    2014-10-01

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

  7. Selection of Levels of Dressing Process Parameters by Using TOPSIS Technique for Surface Roughness of En-31 Work piece in CNC Cylindrical Grinding Machine

    Science.gov (United States)

    Patil, Sanjay S.; Bhalerao, Yogesh J.

    2017-02-01

    Grinding is metal cutting process used for mainly finishing the automobile components. The grinding wheel performance becomes dull by using it most of times. So it should be reshaping for consistent performance. It is necessary to remove dull grains of grinding wheel which is known as dressing process. The surface finish produced on the work piece is dependent on the dressing parameters in sub-sequent grinding operation. Multi-point diamond dresser has four important parameters such as the dressing cross feed rate, dressing depth of cut, width of the diamond dresser and drag angle of the dresser. The range of cross feed rate level is from 80-100 mm/min, depth of cut varies from 10 - 30 micron, width of diamond dresser is from 0.8 - 1.10mm and drag angle is from 40o - 500, The relative closeness to ideal levels of dressing parameters are found for surface finish produced on the En-31 work piece during sub-sequent grinding operation by using Technique of Order Preference by Similarity to Ideal Solution (TOPSIS).In the present work, closeness to ideal solution i.e. levels of dressing parameters are found for Computer Numerical Control (CNC) cylindrical angular grinding machine. After the TOPSIS technique, it is found that the value of Level I is 0.9738 which gives better surface finish on the En-31 work piece in sub-sequent grinding operation which helps the user to select the correct levels (combinations) of dressing parameters.

  8. Space shuttle wheels and brakes

    Science.gov (United States)

    Carsley, R. B.

    1985-01-01

    The Space Shuttle Orbiter wheels were subjected to a combination of tests which are different than any previously conducted in the aerospace industry. The major testing difference is the computer generated dynamic landing profiles used during the certification process which subjected the wheels and tires to simulated landing loading conditions. The orbiter brakes use a unique combination of carbon composite linings and beryllium heat sink to minimize weight. The development of a new lining retention method was necessary in order to withstand the high temperature generated during the braking roll. As with many programs, the volume into which this hardware had to fit was established early in the program, with no provisions made for growth to offset the continuously increasing predicted orbiter landing weight.

  9. Finishing aeronautical planetary herringbone gear wheels in container vibrating smoothing machine

    Directory of Open Access Journals (Sweden)

    Jacek MICHALSKI

    2015-12-01

    Full Text Available The paper presents the technological process of abrasive-chemical machining wheel bearing surface of the cylindrical herringbone gears planetary gear in vibrating container smoothing machine according to Isotropic Finishing ISF® technology of the REM Chemicals Inc. company. Gear wheels are made of stainless Pyrowear 53 and subjected to carburizing, hardening, cold working and low tempering. The change in value of deviation indicators for the kinematic accuracy, smoothness and geometric structure of the machined surfaces of the gear teeth after smoothing compared with the contoured grinding were analyzed. The findings are different a characteristic performance on the surface of the tooth side along the outline, especially with a higher value at the head of the tooths. This creates a need for appropriate modification of the lateral surface of the teeth in the process of contoured grinding. The results of the mechanical strength of the samples gear wheel after the smoothing process and evaluating the hydrogen embrittlement are presented.

  10. The New Grinding Process for Camshaft in Locomotive Engine%机车发动机用凸轮轴磨削新工艺

    Institute of Scientific and Technical Information of China (English)

    王歆令; 李静; 沈南燕; 何永义

    2013-01-01

    According to the geometric characteristics of camshaft in locomotive engine,this paper analyzed the difficulties and disadvantages of traditional grinding process that the concave arc of cam is machined by single type grinding wheel,thus a new grinding process that camshaft is machined by large size and small size grinding wheels was proposed.To avoid the concave arc when machining by large size grinding wheel and guarantee no vibration and impact,the reconstruction of concave arc and optimization of grinding carriage velocity were completed.The experimental results of grinding show that grinding accuracy and efficiency were improved by this new process,which demonstrates its feasibility.%针对机车发动机用凸轮轴几何特征,分析了传统磨削工艺中磨削全程使用一种型号的砂轮对凸轮轮廓的凹弧段进行加工的难点和弊端,提出了大小砂轮配合磨削凸轮轴的新工艺.实施过程中为了保证大砂轮避开凸轮轮廓的凹孤段且加工过程无振动冲击,完成了凸轮凹孤段轮廓重构以及砂轮架速度优化.磨削实验结果表明,采用该新工艺能提高凸轮轴磨削的精度和效率,具有很高的可行性.

  11. Measuring the Dynamic Soil Response During Repeated Wheeling Using Seismic Methods

    DEFF Research Database (Denmark)

    Keller, Thomas; Carizzon, Marco; Berisso, Feto Esimo

    2013-01-01

    was performed with an agricultural tire (60 kN wheel load) on a gleyic Cambisol. We measured Vp using an acoustic (microseismic) device at various depths before, during (i.e., below the tire), and after wheeling. In addition, we measured bulk density and penetrometer resistance before and after wheeling...

  12. The study of sub-surface damage distributions during grinding process on different abrasion materials

    Science.gov (United States)

    Kuo, Ching-Hsiang; Huang, Chien-Yao; Yu, Zong-Ru; Shu, Shyu-Cheng; Chang, Keng-Shou; Hsu, Wei-Yao

    2017-10-01

    The grinding process is the primary technology for curvature generation (CG) on glass optics. The higher material removal rate (MRR) leads to deeper sub-surface damage (SSD) on lens surface. The SSD must be removed by following lapping and polishing processes to ensure the lens quality. However, these are not an easy and an efficient process to remove the SSD from ground surface directly for aspheric surfaces with tens or hundreds microns departure from bestfit- sphere (BFS). An efficient fabrication procedure for large aspheric departure on glass materials must be considered. We propose 3-step fabrication procedures for aspheric surface with larger departure. 1st step is to generate a specific aspheric surface with depth less than 10 μm of SSD residual. 2nd step is to remove SSD and keep the aspheric form by using Zeeko polisher with higher MRR pad. Final step is to figure and finish the aspheric surface by using QED MRF machine. In this study, we focus on the 1st step to investigate the residual depth of SSD after grinding process on different abrasion materials. The materials of tested part are fused silica, S-NPH2, and S-PHM52. The cross grinding would be configured and depth of SSD/surface roughness would be evaluated in this study. The characteristic of SSD could be observed after etching by confocal microscope. The experimental results show the depth of SSD below 31.1 μm with #400 grinding wheel. And the near 10 μm depth of SSD would be achieved with #1,000 grinding wheel. It means the aspherization polishing on large parts with large departure from best fit sphere would be replaced. The fabrication of large aspheric part would be efficient.

  13. Effects of loaded voluntary wheel exercise on performance and muscle hypertrophy in young and old male C57Bl/6J mice.

    Science.gov (United States)

    Soffe, Z; Radley-Crabb, H G; McMahon, C; Grounds, M D; Shavlakadze, T

    2016-02-01

    This study compared the capacity of young and old male C57Bl/6J mice to exercise with increasing resistance over 10 weeks, and its impact on muscle mass. Young mice (aged 15-25 weeks) were subjected to low (LR) and high (HR) resistance exercise, whereas only LR was used for old mice (107-117 weeks). Weekly patterns of voluntary wheel activity, food consumption and body weights were measured. Running patterns changed over time and with age, with two peaks of activity detected for young, but only one for old mice: speed and distance run was also less for old mice. The mass for six limb muscles was measured at the end of the experiment. The most pronounced increase in mass in response to exercise was for the soleus in young and old mice, and also quadriceps and gastrocnemius in young mice. Soleus and quadriceps muscles were analyzed histologically for myofiber number and size. A striking feature was the many small myofibers in response to exercise in young (but not old) soleus, whereas these were not present after exercise in young or old quadriceps. Overall, there was a striking difference in response to exercise between muscles and this was influenced by age. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

    Directory of Open Access Journals (Sweden)

    Zhang Dongkun

    2015-04-01

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

  15. Rolling Friction on a Wheeled Laboratory Cart

    Science.gov (United States)

    Mungan, Carl E.

    2012-01-01

    A simple model is developed that predicts the coefficient of rolling friction for an undriven laboratory cart on a track that is approximately independent of the mass loaded onto the cart and of the angle of inclination of the track. The model includes both deformation of the wheels/track and frictional torque at the axles/bearings. The concept of…

  16. Nonlinear analysis of the GFRP material wheel hub

    Directory of Open Access Journals (Sweden)

    Dong Yun-Feng

    2015-01-01

    Full Text Available In this paper, the current bicycle wheel was replaced by the ones which composed by the wheel hub with Glassfiber Reinforced Plastic (alkali free thin-walled cylinder material, hereinafter referred to as GFRP material and the protective components made up of rubber outer pneumatic pad. With the help of the basic theory of elastic-plastic mechanics, the finite element “Nonlinear buckling” analysis of the wheel was carried out. The results show that the maximum elastic deformation of the wheel hub and the critical value of buckling failure load were restricted by the elasticity under the condition of external loads. Considering with the tensile strength and elastic modulus of the GFRP value of the material, it is demonstrated that the material is feasible to be used for wheel hub.

  17. Effect of surface grinding on chloride induced SCC of 304L

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nian, E-mail: nzh@du.se [Department of Material Science, Dalarna University, SE-79188 Falun (Sweden); KTH, SE-10044 Stockholm (Sweden); Pettersson, Rachel [KTH, SE-10044 Stockholm (Sweden); Jernkontoret, SE-11187 Stockholm (Sweden); Lin Peng, Ru [Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden); Schönning, Mikael [Corrosion Department, Avesta Research Centre – Outokumpu Stainless AB, SE-774 22 Avesta (Sweden)

    2016-03-21

    The effect of surface grinding on the stress corrosion cracking (SCC) behavior of 304L austenitic stainless steel in boiling magnesium chloride has been investigated. SCC tests were conducted both without external loading and with varied levels of four-point bend loading for as-delivered material and for specimens which had been ground parallel or perpendicular to the loading direction. Residual stresses due to the grinding operation were measured using the X-ray diffraction technique. In addition, surface stress measurements under applied load were performed before exposure to evaluate the deviation between actual applied loading and calculated values according to ASTM G39. Micro-cracks initiated by a high level of tensile residual stress in the surface layer were observed for all the ground specimens but not those in the as-delivered condition. Grinding along the loading direction increased the susceptibility to chloride induced SCC; while grinding perpendicular to the loading direction improved SCC resistance. Surface tensile residual stresses were largely relieved after the initiation of cracks.

  18. Effect of surface grinding on chloride induced SCC of 304L

    International Nuclear Information System (INIS)

    Zhou, Nian; Pettersson, Rachel; Lin Peng, Ru; Schönning, Mikael

    2016-01-01

    The effect of surface grinding on the stress corrosion cracking (SCC) behavior of 304L austenitic stainless steel in boiling magnesium chloride has been investigated. SCC tests were conducted both without external loading and with varied levels of four-point bend loading for as-delivered material and for specimens which had been ground parallel or perpendicular to the loading direction. Residual stresses due to the grinding operation were measured using the X-ray diffraction technique. In addition, surface stress measurements under applied load were performed before exposure to evaluate the deviation between actual applied loading and calculated values according to ASTM G39. Micro-cracks initiated by a high level of tensile residual stress in the surface layer were observed for all the ground specimens but not those in the as-delivered condition. Grinding along the loading direction increased the susceptibility to chloride induced SCC; while grinding perpendicular to the loading direction improved SCC resistance. Surface tensile residual stresses were largely relieved after the initiation of cracks.

  19. The Reaction Wheel Pendulum

    CERN Document Server

    Block, Daniel J; Spong, Mark W

    2007-01-01

    This monograph describes the Reaction Wheel Pendulum, the newest inverted-pendulum-like device for control education and research. We discuss the history and background of the reaction wheel pendulum and other similar experimental devices. We develop mathematical models of the reaction wheel pendulum in depth, including linear and nonlinear models, and models of the sensors and actuators that are used for feedback control. We treat various aspects of the control problem, from linear control of themotor, to stabilization of the pendulum about an equilibrium configuration using linear control, t

  20. A Nontoxic Barlow's Wheel

    Science.gov (United States)

    Daffron, John A.; Greenslade, Thomas B.

    2015-01-01

    Barlow's wheel has been a favorite demonstration since its invention by Peter Barlow (1776-1862) in 1822.1 In the form shown in Fig. 1, it represents the first electric motor. The interaction between the electric current passing from the axle of the wheel to the rim and the magnetic field produced by the U-magnet produces a torque that turns the wheel. The original device used mercury to provide electrical contact to the rim, and the dangers involved with the use of this heavy metal have caused the apparatus to disappear from the lecture hall.

  1. Manufacturing processes 2 grinding, honing, lapping

    CERN Document Server

    Klocke, Fritz

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-15

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

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

    Science.gov (United States)

    Khoshaim, Ahmed Bakr

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

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

    International Nuclear Information System (INIS)

    Neseli, Suley Man; Asilturk, Ilhan; Celik, Levent

    2012-01-01

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

  5. Wheeled hopping robot

    Science.gov (United States)

    Fischer, Gary J [Albuquerque, NM

    2010-08-17

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  6. The study of grinding patterns and factors influencing the grinding areas during sleep bruxism.

    Science.gov (United States)

    Tao, Jianxiang; Liu, Weicai; Wu, Junhua; Zhang, Xuying; Zhang, Yongting

    2015-10-01

    The purpose of this study is to investigate the grinding patterns and discuss the factors influencing the position relationship between intercuspal position (ICP) and grinding area during sleep bruxism. Lateral condylar inclination, inclination of lateral incisal path and freedom in long centric of thirty subjects were measured. The grinding patterns during sleep bruxism were recorded with a bruxism recording device, BruxChecker. The position relationship between ICP and the grinding area was examined. Spearman's rank correlation coefficient was used for correlation analysis between grinding area and free factors (grinding patterns, freedom in long centric and discrepancy between lateral condylar inclination and inclination of lateral incisal path). All 12 subjects with 0mm-freedom in long centric exhibited that ICP of both sides located within the grinding areas. 4 subjects showed that ICP of both sides located outside the grinding areas. There is a significant correlation between 0mm-freedom in long centric and ICP within the grinding areas (p grinding area. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Hošek J.

    2013-05-01

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

  8. Further study on the wheel-rail impact response induced by a single wheel flat: the coupling effect of strain rate and thermal stress

    Science.gov (United States)

    Jing, Lin; Han, Liangliang

    2017-12-01

    A comprehensive dynamic finite-element simulation method was proposed to study the wheel-rail impact response induced by a single wheel flat based on a 3-D rolling contact model, where the influences of the structural inertia, strain rate effect of wheel-rail materials and thermal stress due to the wheel-rail sliding friction were considered. Four different initial conditions (i.e. pure mechanical loading plus rate-independent, pure mechanical loading plus rate-dependent, thermo-mechanical loading plus rate-independent, and thermo-mechanical loading plus rate-dependent) were involved into explore the corresponding impact responses in term of the vertical impact force, von-Mises equivalent stress, equivalent plastic strain and shear stress. Influences of train speed, flat length and axle load on the flat-induced wheel-rail impact response were discussed, respectively. The results indicate that the maximum thermal stresses are occurred on the tread of the wheel and on the top surface of the middle rail; the strain rate hardening effect contributes to elevate the von-Mises equivalent stress and restrain the plastic deformation; and the initial thermal stress due to the sliding friction will aggravate the plastic deformation of wheel and rail. Besides, the wheel-rail impact responses (i.e. impact force, von-Mises equivalent stress, equivalent plastic strain, and XY shear stress) induced by a flat are sensitive to the train speed, flat length and axle load.

  9. SCC of 2304 Duplex Stainless Steel-Microstructure, Residual Stress and Surface Grinding Effects.

    Science.gov (United States)

    Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

    2017-02-23

    The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

  10. SCC of 2304 Duplex Stainless Steel—Microstructure, Residual Stress and Surface Grinding Effects

    Directory of Open Access Journals (Sweden)

    Nian Zhou

    2017-02-01

    Full Text Available The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

  11. SCC of 2304 Duplex Stainless Steel—Microstructure, Residual Stress and Surface Grinding Effects

    Science.gov (United States)

    Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

    2017-01-01

    The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental. PMID:28772582

  12. Progress in abrasive and grinding technology

    CERN Document Server

    Xu, Xipeng

    2009-01-01

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

  13. Zirconia changes after grinding and regeneration firing.

    Science.gov (United States)

    Hatanaka, Gabriel R; Polli, Gabriela S; Fais, Laiza M G; Reis, José Maurício Dos S N; Pinelli, Lígia A P

    2017-07-01

    Despite improvements in computer-aided design and computer-aided manufacturing (CAD-CAM) systems, grinding during either laboratory procedures or clinical adjustments is often needed to modify the shape of 3 mol(%) yttria-tetragonal zirconia polycrystal (3Y-TZP) restorations. However, the best way to achieve adjustment is unclear. The purpose of this in vitro study was to evaluate the microstructural and crystallographic phase changes, flexural strength, and Weibull modulus of a 3Y-TZP zirconia after grinding with or without water cooling and regeneration firing. Ninety-six bar-shaped specimens were obtained and divided as follows: as-sintered, control; as-sintered with regeneration firing; grinding without water cooling; grinding and regeneration firing with water cooling; and grinding and regeneration firing. Grinding (0.3 mm) was performed with a 150-μm diamond rotary instrument in a high-speed handpiece. For regeneration firing, the specimens were annealed at 1000°C for 30 minutes. The crystalline phases were evaluated by using x-ray powder diffraction. A 4-point bending test was conducted (10 kN; 0.5 mm/min). The Weibull modulus was used to analyze strength reliability. The microstructure was analyzed by scanning electron microscopy. Data from the flexural strength test were evaluated using the Kruskal-Wallis and Dunn tests (α=.05). Tetragonal-to-monoclinic phase transformation was identified in the ground specimens; R regeneration firing groups showed only the tetragonal phase. The median flexural strength of as-sintered specimens was 642.0; 699.3 MPa for as-sintered specimens with regeneration firing; 770.1 MPa for grinding and water-cooled specimens; 727.3 MPa for specimens produced using water-cooled grinding and regeneration firing; 859.9 MPa for those produced by grinding; and 764.6 for those produced by grinding and regeneration firing; with statistically higher values for the ground groups. The regenerative firing did not affect the flexural

  14. Metastable structure formation during high velocity grinding

    International Nuclear Information System (INIS)

    Samarin, A.N.; Klyuev, M.M.

    1984-01-01

    Metastable structures in surface layers of samples are; investigated during force high-velocity abrasive grinding. Samples of martensitic (40Kh13), austenitic (12Kh18N10T), ferritic (05Kh23Yu5) steels and some alloys, in particular KhN77TYuR (EhI437B), were grinded for one pass at treatment depth from 0.17 up to 2.6 mm. It is established that processes of homogenizing, recrystallization and coagulation are; developed during force high-velocity grinding along with polymorphic transformations in the zone of thermomechanical effect, that leads to changes of physical and mechanical properties of the surface

  15. Automatic grinding apparatus to control uniform specimen thicknesses

    Science.gov (United States)

    Bryner, Joseph S.

    1982-01-01

    This invention is directed to a new and improved grinding apparatus comprising (1) a movable grinding surface, (2) a specimen holder, (3) a displacing device for moving the holder and/or grinding surface toward one another, and (4) at least three devices for limiting displacement of the holder to the grinding surface.

  16. Wheeling in Canada

    International Nuclear Information System (INIS)

    Fytche, E.L.

    1991-01-01

    The quest for economic efficiency, or lowest cost, in the electricity supply industry is furthered by trading between high and low cost utilities, one aspect being transporting or wheeling power through the transmission system of a third party. Some of the pressures and constraints limiting wheeling are discussed. A simple formula is presented for determining whether trading and wheeling are worthwhile. It is demonstrated for assumed capital and operating cost levels, the viability of nine cases where bulk power or economy energy would need to be wheeled across provincial boundaries in order to reach potential buyers. Wheeling in Canada is different from the situation in the USA, due to large distances spanned by Canadian utilities and because most are provincial crown corporations, with different territorial interests and profit motivations than investor-owned utilities. Most trading in electricity has been between contiguous neighbours, for mutual advantage. New technology allows power transmission over distances of up to 1000 miles, and the economics of Canada's electrical supply could be improved, with means including access to low cost coal of Alberta, and remote hydro in British Columbia, Manitoba, Quebec and Labrador. Nuclear plants could be located anywhere but suffer from an unfriendly public attitude. A bridge across the Prairies appears uneconomic due to cost of transmission, and also due to low valuation given to Alberta coal. 7 refs., 2 figs., 3 tabs

  17. The hydraulic wheel

    International Nuclear Information System (INIS)

    Alvarez Cardona, A.

    1985-01-01

    The present article this dedicated to recover a technology that key in disuse for the appearance of other techniques. It is the hydraulic wheel with their multiple possibilities to use their energy mechanical rotational in direct form or to generate electricity directly in the fields in the place and to avoid the high cost of transport and transformation. The basic theory is described that consists in: the power of the currents of water and the hydraulic receivers. The power of the currents is determined knowing the flow and east knowing the section of the flow and its speed; they are given you formulate to know these and direct mensuration methods by means of floodgates, drains and jumps of water. The hydraulic receivers or properly this hydraulic wheels that are the machines in those that the water acts like main force and they are designed to transmit the biggest proportion possible of absolute work of the water, the hydraulic wheels of horizontal axis are the common and they are divided in: you rotate with water for under, you rotate with side water and wheels with water for above. It is analyzed each one of them, their components are described; the conditions that should complete to produce a certain power and formulate them to calculate it. There are 25 descriptive figures of the different hydraulic wheels

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

    International Nuclear Information System (INIS)

    Jodan, K.; Matsumaru, K.; Ishizaki, K.

    2003-01-01

    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

  19. Mathematical simulation of bearing ring grinding process

    Science.gov (United States)

    Koltunov, I. I.; Gorbunova, T. N.; Tumanova, M. B.

    2018-03-01

    The paper suggests the method of forming a solid finite element model of the bearing ring. Implementation of the model allowed one to evaluate the influence of the inner cylindrical surface grinding scheme on the ring shape error.

  20. Reaction Wheel Disturbance Model Extraction Software - RWDMES

    Science.gov (United States)

    Blaurock, Carl

    2009-01-01

    densities); converting PSDs to order analysis data; extracting harmonics; initializing and simultaneously tuning a harmonic model and a wheel structural model; initializing and tuning a broadband model; and verifying the harmonic/broadband/structural model against the measurement data. Functional operation is through a MATLAB GUI that loads test data, performs the various analyses, plots evaluation data for assessment and refinement of analysis parameters, and exports the data to documentation or downstream analysis code. The harmonic models are defined as specified functions of frequency, typically speed-squared. The reaction wheel structural model is realized as mass, damping, and stiffness matrices (typically from a finite element analysis package) with the addition of a gyroscopic forcing matrix. The broadband noise model is realized as a set of speed-dependent filters. The tuning of the combined model is performed using nonlinear least squares techniques. RWDMES is implemented as a MATLAB toolbox comprising the Fit Manager for performing the model extraction, Data Manager for managing input data and output models, the Gyro Manager for modifying wheel structural models, and the Harmonic Editor for evaluating and tuning harmonic models. This software was validated using data from Goodrich E wheels, and from GSFC Lunar Reconnaissance Orbiter (LRO) wheels. The validation testing proved that RWDMES has the capability to extract accurate disturbance models from flight reaction wheels with minimal user effort.

  1. Costs associated with wheeling

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Wheeling costs are incurred by all companies that experience a change in power flows over their transmission lines during a specific transaction, whether or not the lines of that company are part of the contract path. The costs of providing wheeling service differ from one system to another and from one kind of wheeling transaction to another. While most transactions may be completed using existing capacity, others may require an increase in line. Depending on the situation, some cost components may be high, low, negative, or not incurred at all. This article discusses two general categories of costs; transactional and capital. The former are all operation, maintenance and opportunity costs incurred in completing a specific transaction assuming the existence of adequate capacity. Capital costs are the costs of major new equipment purchases and lines necessary to provide any increased level of transmission services

  2. The grinding of uranium dioxide from fluidized beds

    International Nuclear Information System (INIS)

    Alonso Folgueras, J. A.

    1974-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jihui Zhao

    2016-10-01

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

  4. The prospects for retail wheeling

    International Nuclear Information System (INIS)

    O'Donnell, E.H.; Center, J.A.

    1992-01-01

    This paper as published is an outline of a presentation on retail wheeling of electric power. The topics discussed are development of increased wholesale transmission access, government regulatory policies on wholesale transmission, examples of past and present retail transmission access agreements, examples of Federal Energy Regulatory Commission jurisdiction over retail wheeling, and state policies on retail wheeling

  5. Color Wheel Windows

    Science.gov (United States)

    Leonard, Stephanie

    2012-01-01

    In this article, the author describes a painting and drawing lesson which was inspired by the beautiful circular windows found in cathedrals and churches (also known as "rose windows"). This two-week lesson would reinforce both the concept of symmetry and students' understanding of the color wheel. (Contains 1 online resource.)

  6. Atomic Ferris wheel beams

    Science.gov (United States)

    Lembessis, Vasileios E.

    2017-07-01

    We study the generation of atom vortex beams in the case where a Bose-Einstein condensate, released from a trap and moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.

  7. Experiments on a Tail-wheel Shimmy

    Science.gov (United States)

    Harling, R; Dietz, O

    1954-01-01

    Model tests on the "running belt" and tests with a full-scale tail wheel were made on a rotating drum as well as on a runway in order to investigate the causes of the undesirable shimmy phenomena frequently occurring on airplane tail wheels, and the means of avoiding them. The small model (scale 1:10) permitted simulation of the mass, moments of inertia, and fuselage stiffness of the airplane and determination of their influence on the shimmy, whereas by means of the larger model with pneumatic tires (scale 1:2) more accurate investigations were made on the tail wheel itself. The results of drum and road tests show good agreement with one another and with model values. Detailed investigations were made regarding the dependence of the shimmy tendency on trail, rolling speed, load, size of tires, ground friction,and inclination of the swivel axis; furthermore, regarding the influence of devices with restoring effect on the tail wheel, and the friction damping required for prevention of shimmy. Finally observations from slow-motion pictures are reported and conclusions drawn concerning the influence of tire deformation.

  8. Influence of Cooling Condition on the Performance of Grinding Hardened Layer in Grind-hardening

    Science.gov (United States)

    Wang, G. C.; Chen, J.; Xu, G. Y.; Li, X.

    2018-02-01

    45# steel was grinded and hardened on a surface grinding machine to study the effect of three different cooling media, including emulsion, dry air and liquid nitrogen, on the microstructure and properties of the hardened layer. The results show that the microstructure of material surface hardened with emulsion is pearlite and no hardened layer. The surface roughness is small and the residual stress is compressive stress. With cooling condition of liquid nitrogen and dry air, the specimen surface are hardened, the organization is martensite, the surface roughness is also not changed, but high hardness of hardened layer and surface compressive stress were obtained when grinding using liquid nitrogen. The deeper hardened layer grinded with dry air was obtained and surface residual stress is tensile stress. This study provides an experimental basis for choosing the appropriate cooling mode to effectively control the performance of grinding hardened layer.

  9. Microwave-assisted grinding of metallurgical coke

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  10. Improvement of Fatigue Life of Welded Structural Components of a Large Two-Stroke Diesel Engine by Grinding

    DEFF Research Database (Denmark)

    Agerskov, Henning; Hansen, Anders V.; Bjørnbak-Hansen, Jørgen

    2004-01-01

    one side only, with no access to the root side. Various investigations on the fatigue life of the structural components of this new design have been carried out. The present investigation concentrates on the improvement in fatigue life which may be obtained by grinding of the weld toes. The tests...... grinding to m=6 for the test series with grinding. In one of the test series, it was observed that in most cases crack initiation moved from the weld toe to the non-ground surface between the ground areas at the weld toes. Tests were made on steel S 275, on centrally and eccentrically loaded test specimens.......The crankshaft housings of large two-stroke diesel engines are welded structures subjected to constant amplitude loading and designed for infinite life at full design load. A new design of the so-called frame box has been introduced in the engine using butt weld joints of thick plates, welded from...

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

    Science.gov (United States)

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

    2015-12-01

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

  12. Wheels With Sense

    Science.gov (United States)

    Cambridge, Dwayne; Clauss, Douglas; Hewson, Fraser; Brown, Robert; Hisrich, Robert; Taylor, Cyrus

    2002-10-01

    We describe a student intrapreneurial project in the Physics Entrepreneurship Program at Case Western Reserve University. At the request of a major fortune 100 company, a study has been made of the technical and marketing issues for a new business of selling sensors on commercial vehicle wheels for monitoring pressure, temperature, rotations, and vibrations, as well as providing identification. The nature of the physics involved in the choice of the appropriate device such as capacitive or piezoresistive sensors is discussed, along with the possibility of MEMS (micro-electro-mechanical systems) technology and RFID (radiofrequency identification) readout on wheels. Five options (status quo, in-house development, external business acquisition, a large business national partnership, and a small-business Cleveland consortium partnership) were studied from both technological and business perspectives to commercialize the technology. The decision making process for making a choice is explained.

  13. Twyman effect mechanics in grinding and microgrinding.

    Science.gov (United States)

    Lambropoulos, J C; Xu, S; Fang, T; Golini, D

    1996-10-01

    In the Twyman effect (1905), when one side of a thin plate with both sides polished is ground, the plate bends: The ground side becomes convex and is in a state of compressive residual stress, described in terms of force per unit length (Newtons per meter) induced by grinding, the stress (Newtons per square meter) induced by grinding, and the depth of the compressive layer (micrometers). We describe and correlate experiments on optical glasses from the literature in conditions of loose abrasive grinding (lapping at fixed nominal pressure, with abrasives 4-400 μm in size) and deterministic microgrinding experiments (at a fixed infeed rate) conducted at the Center for Optics Manufacturing with bound diamond abrasive tools (with a diamond size of 3-40 μm, embedded in metallic bond) and loose abrasive microgrinding (abrasives of less than 3 μm in size). In brittle grinding conditions, the grinding force and the depth of the compressive layer correlate well with glass mechanical properties describing the fracture process, such as indentation crack size. The maximum surface residual compressive stress decreases, and the depth of the compressive layer increases with increasing abrasive size. In lapping conditions the depth of the abrasive grain penetration into the glass surface scales with the surface roughness, and both are determined primarily by glass hardness and secondarily by Young's modulus for various abrasive sizes and coolants. In the limit of small abrasive size (ductile-mode grinding), the maximum surface compressive stress achieved is near the yield stress of the glass, in agreement with finite-element simulations of indentation in elastic-plastic solids.

  14. Diabetes education on wheels.

    Science.gov (United States)

    Hardway, D; Weatherly, K S; Bonheur, B

    1993-01-01

    Diabetes education programs remain underdeveloped in the pediatric setting, resulting in increased consumer complaints and financial liability for hospitals. The Diabetes Education on Wheels program was designed to provide comprehensive, outcome-oriented education for patients with juvenile diabetes. The primary goal of the program was to enhance patients' and family members' ability to achieve self-care in the home setting. The program facilitated sequential learning, improved consumer satisfaction, and promoted financial viability for the hospital.

  15. Energy requirement for fine grinding of torrefied wood

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-15

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

  16. 49 CFR 570.10 - Wheel assemblies.

    Science.gov (United States)

    2010-10-01

    ... bead through one full wheel revolution and note runout in excess of one-eighth of an inch. (c) Mounting... 49 Transportation 6 2010-10-01 2010-10-01 false Wheel assemblies. 570.10 Section 570.10... Pounds or Less § 570.10 Wheel assemblies. (a) Wheel integrity. A tire rim, wheel disc, or spider shall...

  17. Effects of different cutting strategies on G-ratio in through-feed center-less grinding

    Directory of Open Access Journals (Sweden)

    Alessandro Rascalha

    2017-02-01

    Full Text Available Grinding is the main manufacturing process used in finishing operations. Center-less grinding is widely used in the production of auto parts e.g. roller bearings, valve stem and stem of shock absorbers. Center-less grinding is used in large-scale production due to shorter time and higher flexibility. However, the set-up of the grinder is complex and slow, and depends on the operators’ ability. The choice of the best parameters in the process is important to define exactly the cutting strategy and to optimize the process. Current study analyzes the input parameters: feed rate and type of materials on the responses G-ratio, surface roughness, and roundness. Thus, stems of shock absorbers were used as work pieces on the shop floor. Cutting speed and grinding wheel type were constant. The input parameters comprised feed rate and type of materials (1025 and 1045. Responses were surface roughness, roundness error and G-ratio. Results demonstrated that the kinds of tested material was the parameter that most influenced G-ratio and surface roughness. Moreover, feed rate had little influence on the quality of the work pieces, mainly on roundness error.

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

    Directory of Open Access Journals (Sweden)

    Li Xun

    2015-10-01

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

  19. Finite element analysis of rail-wheel interaction

    International Nuclear Information System (INIS)

    Rahman, F.; Kharlamov, Y.A.; Islam, S.; Khan, A.A.

    2006-01-01

    Damage mechanisms such as surface cracks, plastic deformation and wear can significantly reduce the service life of railway track and rolling stock. They also have a negative impact on the rolling noise as well as: on the riding comfort. A proper understanding of these mechanisms requires a detailed knowledge of physical interaction between wheel and rail. Furthermore, demands for higher train speeds and increased axle loads implies that the consequences of larger contact. forces between wheel and rail must be thoroughly investigated. Two methods have traditionally been used to investigate the rail-wheel contact, that is the Hertz analytical method and simplified numerical method based on the boundary element (BE) method. These methods rely on a half-space assumption and a linear material model. This paper presents that to overcome these limitations, a tool for FE-based quasistatic wheel-rail contact simulations has been developed. The tool is a library of ANSYS macro routines for configuring, meshing and loading of a parametric wheel-rail model. The meshing is based on measured wheel and rail profiles. The wheel and rail materials in the contact region are treated as elastic-plastic with kinematic hardening. By controlling the values of the configuration parameters, representations of various driving cases can be generated. The quasi-static loads are obtained from train motion. Interaction phenomena such as rolling, spinning and sidling can be included. The modeling tool and a methodology are described in the presented paper. Significant differences in the calculated state between the FE solution and the traditional approaches can be observed. These differences are most significant in situations with flange contact. (author)

  20. 30 CFR 57.14115 - Stationary grinding machines.

    Science.gov (United States)

    2010-07-01

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

  1. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Science.gov (United States)

    2010-07-01

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

  2. 30 CFR 56.14115 - Stationary grinding machines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 56.14115 Section... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral hoods capable of...

  3. Grinding Glass Disks On A Belt Sander

    Science.gov (United States)

    Lyons, James J., III

    1995-01-01

    Small machine attached to table-top belt sander makes possible to use belt sander to grind glass disk quickly to specified diameter within tolerance of about plus or minus 0.002 in. Intended to be used in place of production-shop glass grinder. Held on driveshaft by vacuum, glass disk rotated while periphery ground by continuous sanding belt.

  4. Carving up Word Meaning: Portioning and Grinding

    Science.gov (United States)

    Frisson, S.; Frazier, L.

    2005-01-01

    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…

  5. Effects of grinding on certain crystalline structures

    International Nuclear Information System (INIS)

    Tekiz, Y.

    1965-06-01

    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 (β). 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

  6. Tracked Vehicle Road Wheel Puller

    Science.gov (United States)

    2009-02-01

    employed for removing smaller-size components, such as bolts and the like. U.S. Patent No. 5,410,792, issued to Freeman (3), discloses a caster wheel ...separation of the rubberized annular layer from the outer annular surface of the wheel . Figure 5 further illustrates a modification of the wheel puller...2001. 2. Rubino et al. Pulling Tool. U.S. Patent 5,479,688, 1996. 3. Freeman. Caster Wheel Axle Extraction Apparatus. U.S. Patent 5,410,792

  7. Technological capabilities of increasing surface quality of workpieces made of titanium alloy VT22 and stability of surface grinding

    Science.gov (United States)

    Soler, Ya I.; Salov, V. M.; Mai, D. S.

    2018-03-01

    Surface grinding of flat workpieces made of alloy VT22 was conducted by the periphery of a highly porous wheel (HPW) from cubic boron nitride CBN30 B107 100 OV K27 КF40 with three processing techniques (ij). They are 10 - cross-feed per stroke, HPW cutting into a workpiece changes alternately from up to down; 12 – cross-feed per double stroke during the up HPW cutting-in at the working stroke; 22 – cross-feed per double stroke during the down HPW cutting-in at the working stroke. With the involvement of artificial neural network models, it was revealed that to improve the quality of surfaces and stability of its formation, grinding should be conducted if ij = 12.

  8. Modeling and analysis of linearized wheel-rail contact dynamics

    International Nuclear Information System (INIS)

    Soomro, Z.

    2014-01-01

    The dynamics of the railway vehicles are nonlinear and depend upon several factors including vehicle speed, normal load and adhesion level. The presence of contaminants on the railway track makes them unpredictable too. Therefore in order to develop an effective control strategy it is important to analyze the effect of each factor on dynamic response thoroughly. In this paper a linearized model of a railway wheel-set is developed and is later analyzed by varying the speed and adhesion level by keeping the normal load constant. A wheel-set is the wheel-axle assembly of a railroad car. Patch contact is the study of the deformation of solids that touch each other at one or more points. (author)

  9. A mechanical model for deformable and mesh pattern wheel of lunar roving vehicle

    Science.gov (United States)

    Liang, Zhongchao; Wang, Yongfu; Chen, Gang (Sheng); Gao, Haibo

    2015-12-01

    As an indispensable tool for astronauts on lunar surface, the lunar roving vehicle (LRV) is of great significance for manned lunar exploration. An LRV moves on loose and soft lunar soil, so the mechanical property of its wheels directly affects the mobility performance. The wheels used for LRV have deformable and mesh pattern, therefore, the existing mechanical theory of vehicle wheel cannot be used directly for analyzing the property of LRV wheels. In this paper, a new mechanical model for LRV wheel is proposed. At first, a mechanical model for a rigid normal wheel is presented, which involves in multiple conventional parameters such as vertical load, tangential traction force, lateral force, and slip ratio. Secondly, six equivalent coefficients are introduced to amend the rigid normal wheel model to fit for the wheels with deformable and mesh-pattern in LRV application. Thirdly, the values of the six equivalent coefficients are identified by using experimental data obtained in an LRV's single wheel testing. Finally, the identified mechanical model for LRV's wheel with deformable and mesh pattern are further verified and validated by using additional experimental results.

  10. Wheel speed management control system for spacecraft

    Science.gov (United States)

    Goodzeit, Neil E. (Inventor); Linder, David M. (Inventor)

    1991-01-01

    A spacecraft attitude control system uses at least four reaction wheels. In order to minimize reaction wheel speed and therefore power, a wheel speed management system is provided. The management system monitors the wheel speeds and generates a wheel speed error vector. The error vector is integrated, and the error vector and its integral are combined to form a correction vector. The correction vector is summed with the attitude control torque command signals for driving the reaction wheels.

  11. Mechanical Design Engineering Enabler Project wheel and wheel drives

    Science.gov (United States)

    Nutt, Richard E.; Couch, Britt K.; Holley, John L., Jr.; Garris, Eric S.; Staut, Paul V.

    1992-01-01

    Our group was assigned the responsibility of designing the wheel and wheel drive system for a proof-of-concept model of the lunar-based ENABLER. ENABLER is a multi-purpose, six wheeled vehicle designed to lift and transport heavy objects associated with the construction of a lunar base. The resulting design was based on the performance criteria of the ENABLER. The drive system was designed to enable the vehicle to achieve a speed of 7 mph on a level surface, climb a 30 percent grade, and surpass a one meter high object and one meter wide crevice. The wheel assemblies were designed to support the entire weight of the vehicle on two wheels. The wheels were designed to serve as the main component of the vehicle's suspension and will provide suitable traction for lunar-type surfaces. The expected performance of the drive system for the ENABLER was influenced by many mechanical factors. The expected top speed on a level sandy surface is 4 mph instead of the desired 7 mph. This is due to a lack of necessary power at the wheels. The lack of power resulted from dimension considerations that allowed only an eight horsepower engine and also from mechanical inefficiencies of the hydraulic system. However, the vehicle will be able to climb a 30 percent grade, surpass a one meter high object and one meter wide crevice. The wheel assemblies will be able to support the entire weight of the vehicle on two wheels. The wheels will also provide adequate suspension for the vehicle and sufficient traction for lunar-type surfaces.

  12. Investigation on Surface Roughness in Cylindrical Grinding

    Science.gov (United States)

    Rudrapati, Ramesh; Bandyopadhyay, Asish; Pal, Pradip Kumar

    2011-01-01

    Cylindrical grinding is a complex machining process. And surface roughness is often a key factor in any machining process while considering the machine tool or machining performance. Further, surface roughness is one of the measures of the technological quality of the product and is a factor that greatly influences cost and quality. The present work is related to some aspects of surface finish in the context of traverse-cut cylindrical grinding. The parameters considered have been: infeed, longitudinal feed and work speed. Taguchi quality design is used to design the experiments and to identify the significantly import parameter(s) affecting the surface roughness. By utilization of Response Surface Methodology (RSM), second order differential equation has been developed and attempts have also been made for optimization of the process in the context of surface roughness by using C- programming.

  13. First Grinding of a Rock on Mars

    Science.gov (United States)

    2004-01-01

    The round, shallow depression in this image resulted from history's first grinding of a rock on Mars. The rock abrasion tool on NASA's Spirit rover ground off the surface of a patch 45.5 millimeters (1.8 inches) in diameter on a rock called Adirondack during Spirit's 34th sol on Mars, Feb. 6, 2004. The hole is 2.65 millimeters (0.1 inch) deep, exposing fresh interior material of the rock for close inspection with the rover's microscopic imager and two spectrometers on the robotic arm. This image was taken by Spirit's panoramic camera, providing a quick visual check of the success of the grinding. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

  14. Processing equipment for grinding of building powders

    Science.gov (United States)

    Fediuk, R. S.; Ibragimov, R. A.; Lesovik, V. S.; Pak, A. A.; Krylov, V. V.; Poleschuk, M. M.; Stoyushko, N. Y.; Gladkova, N. A.

    2018-03-01

    In the article questions of mechanical grinding up to nanosize of building powder materials are considered. In the process of mechanoactivation of the composite binder, active molecules of cement minerals arise when molecular packets are destroyed in the areas of defects and loosening of the metastable phase during decompensation of intermolecular forces. The process is accompanied by a change in the kinetics of hardening Portland cement. Mechanical processes in the grinding of mineral materials cause, together with an increase in their surface energy, the growth of the isobaric potential of the powders and, accordingly, their chemical activity, which also contributes to high adhesion strength when they come into contact with binders. Thus, a set of measures for mechanical activation allows more fully use the mass of components of the filled cement systems and regulate their properties. At relatively low costs, it is possible to provide an impressive and, importantly, easily repeatable in production conditions result. It is revealed that the use of a vario-planetary mill allows to achieve the best results on grinding the powder building materials.

  15. An elevator wheel

    Energy Technology Data Exchange (ETDEWEB)

    Zhornik, V.I.; Cherkov, Ye.M.; Simonov, A.A.

    1982-01-01

    This invention deals with mineral enrichment and is primarily for unloading submerged products of enrichment during separation in heavy mediums. An elevator wheel is proposed for unloading the submerged product from the bath of a heavy to medium separator which includes ladle disks with internal walls and overlapping sheets hinged to the ends. In order to increase the degree of dehydration of the unloaded product, the internal wall of each ladle is made of sheets installed in stages with clearances relative to each other. The advantages of the proposed device include an improvement in the degree of dehydration of the submerged product in the ladles and a reduction in the carry away of the heavy medium with the enrichment products.

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

    Science.gov (United States)

    Bhattacharyya, Anirban

    The following research fundamentally deals with the cause and implications of nonlinearities in breakage rates of materials in wet grinding systems. The innate dependence of such nonlinearities on fines content and the milling environment during wet grinding operations is also tested and observed. Preferential breakage of coarser size fractions as compared to the finer size fractions in a particle population were observed and discussed. The classification action of the pulp was deemed to be the probable cause for such a peculiarity. Ores with varying degrees of hardness and brittleness were used for wet grinding experiments, primarily to test the variations in specific breakage rates as a function of varying hardness. For this research, limestone, quartzite, and gold ore were used. The degree of hardness is of the order of: limestone, quartzite, gold ore. Selection and breakage function parameters were determined in the course of this research. Functional forms of these expressions were used to compare experimentally derived parameter estimates. Force-fitting of parameters was not done in order to examine the realtime behavior of particle populations in wet grinding systems. Breakage functions were established as being invariant with respect to such operating variables like ball load, mill speed, particle load, and particle size distribution of the mill. It was also determined that specific selection functions were inherently dependent on the particle size distribution in wet grinding systems. Also, they were consistent with inputs of specific energy, according to grind time. Nonlinearity trends were observed for 1st order specific selection functions which illustrated variations in breakage rates with incremental inputs of grind time and specific energy. A mean particle size called the fulcrum was noted below which the nonlinearities in the breakage trends were observed. This magnitude of the fulcrum value varied with percent solids and slurry filling, indicating

  17. Numerical and experimental hydrodynamic study of a coolant distributor for grinding applications

    Directory of Open Access Journals (Sweden)

    Tala Moussa

    2016-01-01

    Full Text Available In grinding, the high frictional energy is converted into heat, which may cause thermal damage and degradation of the wheel and the workpiece. Unwanted thermal effects must thus be reduced, often by external cooling using a curved-duct coolant distributor to match the wheel geometry. The performance of such a system depends strongly on the impinging jet flow properties to ensure efficient sprinkling of the hot spots. The fluid distributor, placed above the workpiece, is pierced with a certain number of identical nozzle fittings, providing multiple jets at the outlet of the nozzles. These jets sprinkle the solids over a given zone and remove the heat by convective transfer. The cooling is hence dependent on the flow structure, meaning the jet diameters, trajectories and velocities, determined up-flow by the distributor design. The present study is devoted to the hydrodynamics aspects of the fluid distributor, aiming to determine the flow-rate distribution at the different orifices and the flow-rate–pressure relationship, for a variety of nozzle diameters and feeding flow rates, under isothermal conditions. A simple hydraulic balance in the device was not able to predict with sufficient accuracy the actual measurements, even when the Venturi effect was accounted for. This discrepancy is due to the curvature of the distributor, inducing secondary flows in interaction with the nozzle outlets, which leads to a rather complex flow pattern. To overcome this issue, a computational fluid dynamics (CFD tool was used and compared with in situ experiments – global flow rate and pressure measurements were additionally taken with particle image velocimetry (PIV to gain insight into the local structure. Simulations were performed with a 3D turbulence model for Reynolds numbers up to 100,000. This model provides an efficient tool for coupling with the thermal study at a later step, allowing global sizing and energetic optimization of the grinding process.

  18. Energy-effective Grinding of Inorganic Solids Using Organic Additives.

    Science.gov (United States)

    Mishra, Ratan K; Weibel, Martin; Müller, Thomas; Heinz, Hendrik; Flatt, Robert J

    2017-08-09

    We present our research findings related to new formulations of the organic additives (grinding aids) needed for the efficient grinding of inorganic solids. Even though the size reduction phenomena of the inorganic solid particles in a ball mill is purely a physical process, the addition of grinding aids in milling media introduces a complex physicochemical process. In addition to further gain in productivity, the organic additive helps to reduce the energy needed for grinding, which in the case of cement clinker has major environmental implications worldwide. This is primarily due to the tremendous amounts of cement produced and almost 30% of the associated electrical energy is consumed for grinding. In this paper, we examine the question of how to optimize these grinding aids linking molecular insight into their working mechanisms, and also how to design chemical additives of improved performance for industrial comminution.

  19. On minimizing mechanical stresses of the rail way wheels

    International Nuclear Information System (INIS)

    Moosavi, H.; Esfahanian, M.

    2000-01-01

    The purpose of this paper is to study the behavior of elastic-plastic stresses under severe drag braking. A railway wheel performs three tasks, aiding in trian movement, supporting the car load, and acting as a brake drum. Finite element computer programs are developed for elasto-plastic stress analysis. An attempt is made here to find an improved fillet profile of the wheel with the intention of minimizing high tensile mechanical stresses. Three new fillet profiles for the wheel are tested. A penalty function is used as a criterion for comparison of stresses between the new designs and the old design. The design with the least penalty is chosen to be the improved one

  20. Modeling of traction-coupling properties of wheel propulsor

    Science.gov (United States)

    Sakhapov, R. L.; Nikolaeva, R. V.; Gatiyatullin, M. H.; Makhmutov, M. M.

    2017-12-01

    In conditions of operation of aggregates on soils with low bearing capacity, the main performance indicators of their operation are determined by the properties of retaining the functional qualities of the propulsor. Therefore, the parameters of the anti-skid device can not be calculated by only one criterion. The equipment of propellers with anti-skid devices, which allow to reduce the compaction effect of the propulsion device on the soil, seems to be a rational solution to the problem of increasing traction and coupling properties of the driving wheels. The mathematical model is based on the study of the interaction of the driving wheel with anti-skid devices and a deformable bearing surface, which takes into account the wheel diameter, skid coefficient, the parameters of the anti-skid device, the physical and mechanical properties of the soil. As a basic mathematical model that determines the dependence of the coupling properties on the wheel parameters, the model obtained as a result of integration and reflecting the process of soil deformation from the shear stress is adopted. The total value of the resistance forces will determine the force of the hitch pressure on the horizontal soil layers, and the value of its deformation is the degree of wheel slippage. When the anti-skid devices interact with the soil, the traction capacity of the wheel is composed of shear forces, soil shear and soil deformation forces with detachable hooks. As a result of the interaction of the hook with the soil, the latter presses against the walls of the hook with the force equal to the sum of the hook load and the resistance to movement. During operation, the linear dimensions of the hook will decrease, which is not taken into account by the safety factor. Abrasive wear of the thickness of the hook is approximately proportional to the work of friction caused by the movement of the hook when inserted into the soil and slipping the wheel.

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

    OpenAIRE

    Lek Sikong; Kalayanee Kooptanond; Noparit Morasut; Thammasak Pongprasert

    2008-01-01

    Various variables affecting grinding, such as air pressure, minerals or materials hardness, feed size were investigated.The limitations of grinding of gypsum, barite, ilmenite, quartz and ferrosilicon were also elucidated by means of particlefineness size distribution and morphology of ground products. It was found that:1) The density of particles, which are in the grinding zone affects the product fineness, i.e. higher feed rate resultsin a larger product size. The appropriate feed rate is s...

  2. Voluntary Wheel Running in Mice.

    Science.gov (United States)

    Goh, Jorming; Ladiges, Warren

    2015-12-02

    Voluntary wheel running in the mouse is used to assess physical performance and endurance and to model exercise training as a way to enhance health. Wheel running is a voluntary activity in contrast to other experimental exercise models in mice, which rely on aversive stimuli to force active movement. This protocol consists of allowing mice to run freely on the open surface of a slanted, plastic saucer-shaped wheel placed inside a standard mouse cage. Rotations are electronically transmitted to a USB hub so that frequency and rate of running can be captured via a software program for data storage and analysis for variable time periods. Mice are individually housed so that accurate recordings can be made for each animal. Factors such as mouse strain, gender, age, and individual motivation, which affect running activity, must be considered in the design of experiments using voluntary wheel running. Copyright © 2015 John Wiley & Sons, Inc.

  3. Wheels lining up for ATLAS

    CERN Multimedia

    2003-01-01

    On 30 October, the mechanics test assembly of the central barrel of the ATLAS tile hadronic calorimeter was completed in building 185. It is the second wheel for the Tilecal completely assembled this year.

  4. Grinding tool for making hemispherical bores in hard materials

    Science.gov (United States)

    Duran, E.L.

    1985-04-03

    A grinding tool for forming hemispherical bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.

  5. Utility of an unitary-shredding method to evaluate the conditions and selection of constructional features during grinding

    Directory of Open Access Journals (Sweden)

    Macko Marek

    2018-01-01

    Full Text Available In order to evaluate and improve the efficiency of the process of grinding, various investigations are conducted, based on the relevant research methodology. One of them is the method in which the crushed sample is subjected to single stroke loads. On this basis, the influence of the geometric features of the chipper system and the dynamic process on the efficiency of the grinding is determined. Charpy hammers instrument were used to perform these modifications so that the momentary force of the resistance could be recorded with varying sample alignment, blade geometry changes and others. In addition, it was proposed to use a super fast camera (up to 1200 fps to record the deformation of the sample and its destruction, in order to interpretation the burdens there. Under such idealized conditions, a range of variables has been identified that significantly affect the reduction of energy demand during grinding.

  6. Performance assessment of river sand versus ceramic grinding media on the Fimiston Ultra-fine Grinding application

    International Nuclear Information System (INIS)

    Blake, Guillaume; Clermont, Benoit; Gianatti, Christopher

    2012-01-01

    Ultra-fine grinding increases the amenability of the refractory concentrate to direct cyanide leaching. Low cost media such as silica river sand gives very fine product grind sizes, however the sand media is quite angular and is often supplied with a broad size distribution. It is generally accepted that the use of a ceramic grinding media will result in a finer product size or allow an increase in the mill throughput. The capacity of a mill is known to increase with decreasing grinding media diameter, the mill wear can be decreased and efficiency of grinding increased. Magotteaux Keramax-MTX Ceramic grinding media was purchased for a plant trial, to assess its' performance.

  7. Fiscal 1999 achievement report. Development of technology for machine tool with energy consumption rationalized (Research and development of environment-conscious grinding system); 1999 nendo energy shiyo gorika kosaku kikai nado gijutsu kaihatsu seika hokokusho. Kankyo taiogata kensaku kako system no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    A large quantity of coolant is used in the grinding process for ensuring high accuracy and quality in the work. This presents a serious problem from the viewpoint of environmental impact or energy conservation, and now environment-conscious grinding methods requiring no or less coolant are sought for. With a view to answering the demand, efforts are exerted to put to practical use, and improve, an EcoloG grinding technique. The goal is to reduce to half the energy that the grinding process is now consuming. The EcoloG technique is a grinding method under which vegetable oil mist is cooled for lubrication and a small amount of cooling water is fed to the point of grinding for removing chips. In fiscal 1999, a survey was conducted on technical literature, patents, and the like in and out of Japan for the study of the actual state of dry machining, and then the course of future studies was clearly established. Studies were also carried out aiming at the practical application and improvement of the EcoloG grinding technique, and the technique achieved a quality level as high as that of the conventional coolant-aided method in a process of grinding a shaft to have an accurate outer diameter by use of an ordinary wheel head. (NEDO)

  8. Estimating the Backup Reaction Wheel Orientation Using Reaction Wheel Spin Rates Flight Telemetry from a Spacecraft

    Science.gov (United States)

    Rizvi, Farheen

    2013-01-01

    A report describes a model that estimates the orientation of the backup reaction wheel using the reaction wheel spin rates telemetry from a spacecraft. Attitude control via the reaction wheel assembly (RWA) onboard a spacecraft uses three reaction wheels (one wheel per axis) and a backup to accommodate any wheel degradation throughout the course of the mission. The spacecraft dynamics prediction depends upon the correct knowledge of the reaction wheel orientations. Thus, it is vital to determine the actual orientation of the reaction wheels such that the correct spacecraft dynamics can be predicted. The conservation of angular momentum is used to estimate the orientation of the backup reaction wheel from the prime and backup reaction wheel spin rates data. The method is applied in estimating the orientation of the backup wheel onboard the Cassini spacecraft. The flight telemetry from the March 2011 prime and backup RWA swap activity on Cassini is used to obtain the best estimate for the backup reaction wheel orientation.

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

    Science.gov (United States)

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

    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…

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

    Science.gov (United States)

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

    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…

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

    Science.gov (United States)

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

    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…

  12. Effect of Grinding and Multi-Stimuli Aging on the Fatigue Strength of a Y-TZP Ceramic.

    Science.gov (United States)

    Silvestri, Tais; Pereira, Gabriel Kalil Rocha; Guilardi, Luis Felipe; Rippe, Marilia Pivetta; Valandro, Luiz Felipe

    2018-01-01

    This study aimed to investigate the effect of grinding and multi-stimuli aging on the fatigue strength, surface topography and the phase transformation of Y-TZP ceramic. Discs were manufactured according to ISO-6872:2008 for biaxial flexure testing (diameter: 15 mm; thickness: 1.2 mm) and randomly assigned considering two factors "grinding" and "aging": C- control (as-sintered); CA- control + aging; G- ground; GA- ground + aging. Grinding was carried out with coarse diamond burs under water-cooling. Aging protocols consisted of: autoclave (134°C, 2 bars pressure, 20 hours), followed by storage for 365 days (samples were kept untouched at room temperature), and by mechanical cycling (106 cycles by 20 Hz under a load of 50% from the biaxial flexure monotonic tests). Flexural fatigue strengths (20,000 cycles; 6 Hz) were determined under sinusoidal cyclic loading using staircase approach. Additionally, surface topography analysis by FE-SEM and phase transformation analysis by X-ray Diffractometry were performed. Dixon and Mood methodology was used to analyze the fatigue strength data. Grinding promotes alterations of topographical pattern, while aging apparently did not alter it. Grinding triggered t-m phase transformation without impacting the fatigue strength of the Y-TZP ceramic; and aging promoted an intense t-m transformation that resulted in a toughening mechanism leading to higher fatigue strength for as-sintered condition, and a tendency of increase for ground condition (C grinding and aging procedures did not affect deleteriously the fatigue strength of the evaluated Y-TZP ceramic, although, it promotes surface topography alterations, except to aging, and t-m phase transformation.

  13. Quenching simulation of steel grinding balls

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  14. Cerâmicas avançadas no processo de retificação cilíndrica externa de mergulho com rebolos diamantados com a técnica da mímima quantidade de lubrificação e refrigeração otimizada Advanced ceramics in the external cylindrical plunge grinding using the technique of minimum quantity of lubrication and the technique of optimized refrigeration with diamond wheels

    Directory of Open Access Journals (Sweden)

    M. H. Oikawa

    2011-09-01

    high wear resistance. For this reason they are able to be used in situations that require little wear, both at ambient temperature or at elevated temperatures. These properties have made the advanced ceramics an important part in industry applications in recent decades. However, the aggregated cost in the piece finishing is still very high. This finish is usually done by the grinding process, the only economically viable process that produces pieces with high surface quality and geometric precision. The companies are then looking for optimizing the grinding process exploring other forms of lubrication. Thus, this project sought to explore the optimization of the method of lubrication in the cylindrical grinding with the technique of minimum quantity of lubrication (MQL and optimized cooling. Three methods of cooling were used, the conventional, the MQL and the optimized cooling, with three speeds of depth in each case. The output variables G Ratio, roughness and circularity errors were analyzed. The analysis shows that the optimal cooling gives the best results, being a viable alternative to improve the process. The MQL showed unsatisfactory results in comparison to the other two methods, but still acceptable in some cases of grinding process. Considering the difficulty and high cost of disposal of cutting fluid due to the strict environmental laws, the MQL comes as a strong trend in this type of process.

  15. Occlusal Grinding Pattern during Sleep Bruxism and Temporomandibular Disorder

    Directory of Open Access Journals (Sweden)

    Yeni Wijaya

    2013-09-01

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

  16. Assessment of Metallic Contaminants in Grinded Millet using ...

    African Journals Online (AJOL)

    OLUWASOGO

    Separate grinding discs were used for different millet forms, while the same quantity of millet ... have bad effects on human health (Normayo et al, 2010, Edem et al, 2012 .... grinding discs to have close contact due to the hardness of the millet.

  17. 7 CFR 58.726 - Cutting and grinding.

    Science.gov (United States)

    2010-01-01

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

  18. Dynamic Modeling and Vibration Analysis for the Vehicles with Rigid Wheels Based on Wheel-Terrain Interaction Mechanics

    Directory of Open Access Journals (Sweden)

    Jianfeng Wang

    2015-01-01

    Full Text Available The contact mechanics for a rigid wheel and deformable terrain are complicated owing to the rigid flexible coupling characteristics. Bekker’s equations are used as the basis to establish the equations of the sinking rolling wheel, to vertical load pressure relationship. Since vehicle movement on the Moon is a complex and on-going problem, the researcher is poised to simplify this problem of vertical loading of the wheel. In this paper, the quarter kinetic models of a manned lunar rover, which are both based on the rigid road and deformable lunar terrain, are used as the simulation models. With these kinetic models, the vibration simulations were conducted. The simulation results indicate that the quarter kinetic model based on the deformable lunar terrain accurately reflects the deformable terrain’s influence on the vibration characteristics of a manned lunar rover. Additionally, with the quarter kinetic model of the deformable terrain, the vibration simulations of a manned lunar rover were conducted, which include a parametric analysis of the wheel parameters, vehicle speed, and suspension parameters. The results show that a manned lunar rover requires a lower damping value and stiffness to achieve better vibration performance.

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

    Directory of Open Access Journals (Sweden)

    Manoel Cléber de Sampaio Alves

    2008-06-01

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

  20. Design procedure for a wind-wheel with self-adjusting blade mechanism

    Directory of Open Access Journals (Sweden)

    Gennady A. Oborsky

    2014-12-01

    Full Text Available Developed is a wind-wheel design equipped with the self-adjusting blade. The blade is positioned eccentrically to the balance wheel and can freely rotate around its axis. Elaborated is the method of calculating the energy characteristics for a wind-wheel with the self-adjusting blade, considering not only the wind force but the force of air counter flow resistance to the blade’s rotation. Initially, the blade being located at an angle α = 45 to the wheel rotation plane, the air flow rotates the wheel with the maximum force. Thus, the speed of rotation increases that involves the increase in air counter flow resistance and results in blade turning with respective angle α reduction. This, consequently, reduces the torque. When the torsional force and the resistance enter into equilibrium, the blade takes a certain angle α, and the wheel speed becomes constant. This wind-wheel design including a self-adjusting blade allows increasing the air flow load ratio when compared to the wind-wheel equipped with a jammed blade.

  1. Voluntary resistance running wheel activity pattern and skeletal muscle growth in rats.

    Science.gov (United States)

    Legerlotz, Kirsten; Elliott, Bradley; Guillemin, Bernard; Smith, Heather K

    2008-06-01

    The aims of this study were to characterize the pattern of voluntary activity of young rats in response to resistance loading on running wheels and to determine the effects of the activity on the growth of six limb skeletal muscles. Male Sprague-Dawley rats (4 weeks old) were housed individually with a resistance running wheel (R-RUN, n = 7) or a conventional free-spinning running wheel (F-RUN, n = 6) or without a wheel, as non-running control animals (CON, n = 6). The torque required to move the wheel in the R-RUN group was progressively increased, and the activity (velocity, distance and duration of each bout) of the two running wheel groups was recorded continuously for 45 days. The R-RUN group performed many more, shorter and faster bouts of running than the F-RUN group, yet the mean daily distance was not different between the F-RUN (1.3 +/- 0.2 km) and R-RUN group (1.4 +/- 0.6 km). Only the R-RUN resulted in a significantly (P RUN and R-RUN led to a significantly greater wet mass relative to increase in body mass and muscle fibre cross-sectional area in the soleus muscle compared with CON. We conclude that the pattern of voluntary activity on a resistance running wheel differs from that on a free-spinning running wheel and provides a suitable model to induce physiological muscle hypertrophy in rats.

  2. Mandibular condylar morphology for bruxers with different grinding patterns.

    Science.gov (United States)

    Tao, Jianxiang; Wu, Junhua; Zhang, Xuying

    2016-07-01

    The purpose of this study was to investigate the mandibular condylar morphology for bruxers with different grinding patterns. Condylar sectional morphology and condylar position of 30 subjects were determined by two viewers using cone beam computed tomography (CBCT) image data sets. The grinding patterns during sleep bruxism (SB) were determined objectively using a Brux-checker device.Chi-square tests were used for statistical analysis for the condylar morphology type between different tooth grinding patterns. Spearman's rank correlation coefficient was used for correlation analysis between condylar position and the canine guidance area during SB. Theincidence of condylarmorphologicaldivergence from idealwas35%.There isa significant difference in distribution of condylar morphology type between the group grinding (GG) and GG combined with mediotrusive side grinding (MG) (p < 0.05). There was no significant correlation between condylar position and canine guidance area during bruxism. MG during SB is associated with condylar morphology that is considered not to be ideal.

  3. An Omni-Directional Wall-Climbing Microrobot with Magnetic Wheels Directly Integrated with Electromagnetic Micromotors

    Directory of Open Access Journals (Sweden)

    Xiaoning Tang

    2012-04-01

    Full Text Available This paper presents an omni-directional wall-climbing microrobot with magnetic wheels. The integral design with an actuator and adhesive is realized by integrating stators and rotors of an MEMS-based electromagnetic micromotor with a magnetic wheel. The omni-directional wall-climbing mechanism is designed by a set of steering gears and three standard magnetic wheels. The required torque and magnetic force for microrobot movement are derived by its static analysis. The size of the magnetic wheel is optimized, with consideration of its own design constraints, by ANSOFT and Pro/Engineer simulation so as to reduce unnecessary torque consumption under the same designed load. Related experiments demonstrate that the microrobot (diameter: 26mm; height: 16.4; mass: 7.2g; load capacity: 3g we have developed has a good wall-climbing ability and flexible mobility, and it can perform visual detection in a ferromagnetic environment.

  4. Development of an omnidirectional Automated Guided Vehicle with MY3 wheels

    Directory of Open Access Journals (Sweden)

    Suyang Yu

    2016-03-01

    Full Text Available This paper presents an omnidirectional Automated Guided Vehicle (AGV with a novel omnidirectional wheel named MY3 wheel. Due to the special structure and material of the MY3 wheel, the AGV has full three DOFs in the motion plane and good capabilities of load carrying and slip resisting. In addition, the kinematic model of the AGV is derived, and the guiding method that can make the AGV to follow a specified path is established. Finally, experiments are performed to verify the kinematic model and guiding method.

  5. Two new wheels for ATLAS

    CERN Multimedia

    2002-01-01

    Juergen Zimmer (Max Planck Institute), Roy Langstaff (TRIUMF/Victoria) and Sergej Kakurin (JINR), in front of one of the completed wheels of the ATLAS Hadronic End Cap Calorimeter. A decade of careful preparation and construction by groups in three continents is nearing completion with the assembly of two of the four 4 m diameter wheels required for the ATLAS Hadronic End Cap Calorimeter. The first two wheels have successfully passed all their mechanical and electrical tests, and have been rotated on schedule into the vertical position required in the experiment. 'This is an important milestone in the completion of the ATLAS End Cap Calorimetry' explains Chris Oram, who heads the Hadronic End Cap Calorimeter group. Like most experiments at particle colliders, ATLAS consists of several layers of detectors in the form of a 'barrel' and two 'end caps'. The Hadronic Calorimeter layer, which measures the energies of particles such as protons and pions, uses two techniques. The barrel part (Tile Calorimeter) cons...

  6. Local cyclic deformation behavior and microstructure of railway wheel materials

    International Nuclear Information System (INIS)

    Walther, F.; Eifler, D.

    2004-01-01

    The current investigations concentrate on the relation between the loading and environmental conditions, the local microstructure and the fatigue behavior of highly stressed railway wheel and tire steels. Experiments under stress control and total strain control were performed at ambient temperature with servohydraulic testing systems. Superimposed mean loadings allow an evaluation of cyclic creep and mean stress relaxation effects. Strain, temperature and electrical measuring techniques were used to characterize the cyclic deformation behavior of specimens from different depth positions of the cross-sections of UIC-specified wheel components (UIC: International Railway Union). The measured values show a strong interrelation. The microstructural characterization of the different material conditions was done by light and scanning electron microscopy together with digital image processing

  7. Reasons for service failure of an ÉKG-20 power shovel bogie wheel

    Science.gov (United States)

    Yakovleva, S. P.; Milokhin, S. E.

    1985-10-01

    Early failure of a bogie wheel is caused by the occurrence after heat treatment of a working surface structure with insufficient resistance to plastic deformation, which under the specific conditions of contact loading causes flattening of it with the formation of accumulations of material on the side surfaces. This leads to the occurrence of significant stresses on the faces of the wheel which intensify the nonuniformity of the structure obtained after machining of the side surface.

  8. Propulsion Wheel Motor for an Electric Vehicle

    Science.gov (United States)

    Figuered, Joshua M. (Inventor); Herrera, Eduardo (Inventor); Waligora, Thomas M. (Inventor); Bluethmann, William J. (Inventor); Farrell, Logan Christopher (Inventor); Lee, Chunhao J. (Inventor); Vitale, Robert L. (Inventor); Winn, Ross Briant (Inventor); Eggleston, IV, Raymond Edward (Inventor); Guo, Raymond (Inventor); hide

    2016-01-01

    A wheel assembly for an electric vehicle includes a wheel rim that is concentrically disposed about a central axis. A propulsion-braking module is disposed within an interior region of the wheel rim. The propulsion-braking module rotatably supports the wheel rim for rotation about the central axis. The propulsion-braking module includes a liquid cooled electric motor having a rotor rotatable about the central axis, and a stator disposed radially inside the rotor relative to the central axis. A motor-wheel interface hub is fixedly attached to the wheel rim, and is directly attached to the rotor for rotation with the rotor. The motor-wheel interface hub directly transmits torque from the electric motor to the wheel rim at a 1:1 ratio. The propulsion-braking module includes a drum brake system having an electric motor that rotates a cam device, which actuates the brake shoes.

  9. Analysis of power wheeling services

    Energy Technology Data Exchange (ETDEWEB)

    Tepel, R.C.; Jewell, W.; Johnson, R.; Maddigan, R.

    1986-11-01

    Purpose of this study is to examine existing wheeling arrangements to determine the terms of the agreements, to analyze the terms relative to regulatory goals, and finally, to suggest ways in which the arrangements can be modified to lead to outcomes more closely in line with the goals. The regulatory goals that are considered are: Does the arrangement meet the revenue requirement of the wheeling firm. Is efficient use promoted. Are the costs fairly apportioned. And, is the arrangement practical and feasible to implement.

  10. Performance of Metal Cutting on Endmills Manufactured by Cooling-Air and Minimum Quantity Lubrication Grinding

    Science.gov (United States)

    Inoue, Shigeru; Aoyama, Tojiro

    Grinding fluids have been commonly used during the grinding of tools for their cooling and lubricating effect since the hard, robust materials used for cutting tools are difficult to grind. Grinding fluids help prevent a drop in hardness due to burning of the cutting edge and keep chipping to an absolute minimum. However, there is a heightened awareness of the need to improve the work environment and protect the global environment. Thus, the present study is aimed at applying dry grinding, cooling-air grinding, cooling-air grinding with minimum quantity lubrication (MQL), and oil-based fluid grinding to manufacturing actual endmills (HSS-Co). Cutting tests were performed by a vertical machining center. The results indicated that the lowest surface inclination values and longest tool life were obtained by cooling-air grinding with MQL. Thus, cooling-air grinding with MQL has been demonstrated to be at least as effective as oil-based fluid grinding.

  11. Effect of grinding on the fatigue life of titanium alloy (5 Al-2.5 Sn) under dry and wet conditions

    Science.gov (United States)

    Rangaswamy, Partha; Terutung, Hendra; Jeelani, Shaik

    1989-01-01

    The principal factors in the performance of aerospace materials are strength-to-weight ratio, fatigue life, fracture toughness, survivability and, of course, reliability. Machining processes and, in particular, grinding under adverse conditions have been found to cause damage to surface integrity and affect the residual stress distribution in the surface and subsurface region. These effects have a direct bearing on the fatigue life. In this investigation the effects of grinding conditions on the fatigue life of Titanium 5 Al-2.5Sn were studied. This alloy is used in ground form in the manufacturing of some critical components in the space shuttle's main engine. It is essential that materials for such applications be properly characterized for use in severe service conditions. Flat sub-size specimens 0.1 inch thick were ground on a surface grinding machine equipped with a variable speed motor at speeds of 2000 to 6000 rpm using SiC wheels of grit sizes 60 and 120. The grinding parameters used in this investigation were chosen from a separate study. The ground specimens were then fatigued at a selected stress and the resulting lives were compared with that of the virgin material. The surfaces of the specimens were examined under a scanning electron microscope, and the roughness and hardness were measured using a standard profilometer and microhardness tester, respectively. The fatigue life of the ground specimens was found to decrease with the increase in speed for both dry and wet conditions. The fatigue life of specimens ground under wet conditions showed a significant increase at the wheel speed of 2000 rpm for both the grit sizes and thereafter decreased with increase profilometry, microhardness measurements and scanning electron microscopic examination.

  12. 49 CFR 229.73 - Wheel sets.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Wheel sets. 229.73 Section 229.73 Transportation... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Suspension System § 229.73 Wheel sets. (a...) when applied or turned. (b) The maximum variation in the diameter between any two wheel sets in a three...

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

  14. Study on the status of the working bodies grinding machines based on vibration analysis

    Directory of Open Access Journals (Sweden)

    S. T. Antipov

    2016-01-01

    Full Text Available Improvement of technology and engineering aimed at the use of secondary raw material is an important task. One of the most important operations in the preparation of raw materials for mixed feeds is fine grinding. In this regard, the article discusses the grinding equipment allowing to obtain raw materials of higher quality with the lower energy consumption. Methods and diagnostic tools were proposed, the principle of determining the locations (points of installation of vibration measurement sensors as well as the choice of the vibration signal analysis method were considered. Investigation of the state of the disintegrator working bodies was carried out in the workshop of LLC PСF "Luch 2000". The object of study is a disintegrator with rotors diameter of 350 mm, each of them having two rows of pins. The result of the experiment revealed that during the operation the working bodies of grinding machines are exposed to uneven wear and under the action of multicycle load micro-cracks and fatigue fractures occur. The method of spectral analysis revealed the appearance of harmonics with large vibration at a frequency of 126 Hz, as well as multiple frequencies, allowing a high degre e of probability to determine not only the actual state of the working bodies, but also to predict the defect development trend. Based on the analysis of the spectra, the decision on further time operation of the equipment is made, which significantly reduces the probability of an emergency stop of equipment and expensive repairs. The research data will be relevant when using vibration diagnostics tools in enterprises, as well as in the design, construction and choice of materials for grinding equipment.

  15. A new solution method for wheel/rail rolling contact.

    Science.gov (United States)

    Yang, Jian; Song, Hua; Fu, Lihua; Wang, Meng; Li, Wei

    2016-01-01

    To solve the problem of wheel/rail rolling contact of nonlinear steady-state curving, a three-dimensional transient finite element (FE) model is developed by the explicit software ANSYS/LS-DYNA. To improve the solving speed and efficiency, an explicit-explicit order solution method is put forward based on analysis of the features of implicit and explicit algorithm. The solution method was first applied to calculate the pre-loading of wheel/rail rolling contact with explicit algorithm, and then the results became the initial conditions in solving the dynamic process of wheel/rail rolling contact with explicit algorithm as well. Simultaneously, the common implicit-explicit order solution method is used to solve the FE model. Results show that the explicit-explicit order solution method has faster operation speed and higher efficiency than the implicit-explicit order solution method while the solution accuracy is almost the same. Hence, the explicit-explicit order solution method is more suitable for the wheel/rail rolling contact model with large scale and high nonlinearity.

  16. Desiccant wheels for air humidification: An experimental and numerical analysis

    International Nuclear Information System (INIS)

    De Antonellis, Stefano; Intini, Manuel; Joppolo, Cesare Maria; Molinaroli, Luca; Romano, Francesco

    2015-01-01

    Highlights: • The use of desiccant wheel to humidify an air stream is investigated. • Air humidification is obtained by extracting water vapour from outdoor air. • Experimental tests in winter humidification conditions are performed. • The design of the proposed humidification system is numerically analyzed. • Effects of boundary conditions on humidification capacity are investigated. - Abstract: In this work the use of a desiccant wheel for air humidification is investigated through a numerical and experimental approach. In the proposed humidification system, water vapour is adsorbed from outdoor environment and it is released directly to the air stream supplied to the building. Such a system can be an interesting alternative to steam humidifiers in hospitals or, more generally, in applications where air contamination is a critical issue and therefore adiabatic humidifiers are not allowed. Performance of the proposed system is deeply investigated and optimal values of desiccant wheel configuration parameters are discussed. It is shown that in the investigated conditions, which are representative of Southern Europe winter climate, the system can properly match the latent load of the building. Finally, power consumption referred to the primary source of the proposed humidification system is compared to the one of steam humidifiers. The present analysis is carried out through experimental tests of a desiccant wheel in winter humidification conditions and through a phenomenological model of the device, based on heat and mass transfer equations.

  17. Eco-efficiency of grinding processes and systems

    CERN Document Server

    Winter, Marius

    2016-01-01

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

  18. Grinding temperature and energy ratio coefficient in MQL grinding of high-temperature nickel-base alloy by using different vegetable oils as base oil

    Directory of Open Access Journals (Sweden)

    Li Benkai

    2016-08-01

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

  19. Experimental Study of Tool Wear and Grinding Forces During BK-7 Glass Micro-grinding with Modified PCD Tool

    Science.gov (United States)

    Pratap, A.; Sahoo, P.; Patra, K.; Dyakonov, A. A.

    2017-09-01

    This study focuses on the improvement in grinding performance of BK-7 glass using polycrystalline diamond micro-tool. Micro-tools are modified using wire EDM and performance of modified tools is compared with that of as received tool. Tool wear of different types of tools are observed. To quantify the tool wear, a method based on weight loss of tool is introduced in this study. Modified tools significantly reduce tool wear in comparison to the normal tool. Grinding forces increase with machining time due to tool wear. However, modified tools produce lesser forces thus can improve life of the PCD micro-grinding tool.

  20. Grinding of Inconel 713 superalloy for gas turbines

    Czech Academy of Sciences Publication Activity Database

    Čapek, J.; Kyncl, J.; Kolařík, K.; Beránek, L.; Pitrmuc, Z.; Medřický, Jan; Pala, Z.

    2016-01-01

    Roč. 16, č. 1 (2016), s. 14-15 ISSN 1213-2489 Institutional support: RVO:61389021 Keywords : Casting defects * Gas turbine * Grinding * Nickel superalloy * Residual stresses Subject RIV: JJ - Other Materials

  1. Gemstone Grinding Process Improvement by using Impedance Force Control

    Directory of Open Access Journals (Sweden)

    Hamprommarat Chumpol

    2015-01-01

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

  2. short communication simple grinding-induced reactions of 2

    African Journals Online (AJOL)

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    SIMPLE GRINDING-INDUCED REACTIONS OF 2-AMINOBENZYL ... As part of our broad interest in the chemistry of heterocyclic compounds [10, 11], the .... study grant) and the University of Botswana (THT study grant) for financial support, Dr.

  3. Comparison of Wet and Dry Grinding in Electromagnetic Mill

    Directory of Open Access Journals (Sweden)

    Szymon Ogonowski

    2018-03-01

    Full Text Available Comparison of dry and wet grinding process in an electromagnetic mill is presented in this paper. The research was conducted in a batch copper ore grinding. Batch mode allows for precise parametrization and constant repetitive conditions of the experiments. The following key aspects were tested: processing time, feed size, size of the grinding media, mass of the material and graining media, and density of the pulp. The particles size distribution of the product samples was analyzed in the laboratory after each experiment. The paper discusses the experimental results as well as the concept of dry and wet grinding and classification circuits for the electromagnetic mill. The main points of the discussion are the size reduction effectiveness and power consumption of the entire system.

  4. Grinding as a method of meat texture evaluation.

    Science.gov (United States)

    Kenmegne Kamdem, A T; Hardy, J

    1995-01-01

    An electric grinder equipped with a torque/speed sensor was used to evaluate maximum grinding torque (T(max)) and total energy (TE) necessary to grind 150 g of uncooked meat. Texture profile analysis (TPA), relaxation and cutting tests were carried out and sample compositions were also determined. The degree of dependence between grinding, TPA, relaxation, cutting parameters and sample composition was checked. Results showed that grinding parameters (T(max) and TE) correlated better with TPA, relaxation and cutting parameters than with composition. In particular correlation coefficient of -0·92, -0·92 and 0·97 were obtained, respectively, between T(max) and relaxation percentage (%R), T(max) and destructuring coefficient at 25% conmpression (De(25)) and between T(max) and maximum cutting force (F(c)).

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

    Directory of Open Access Journals (Sweden)

    Korotkov Aleksandr

    2017-01-01

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

  6. Damages and resource of locomotive wheels used under the north operating conditions

    Directory of Open Access Journals (Sweden)

    A. V. Grigorev

    2014-01-01

    Full Text Available In operating railway equipment, in particular the elements, such as a wheel and a rail there is damage accumulation of any kind, causing a premature equipment failure. Thus, an analysis of the mechanisms and modeling of damage accumulation and fracture both on the surface and in the bulk material remain a challenge.Data on the defective wheel sets to be subjected to facing has been collected and analyzed to assess the locomotive wheel sets damage of the locomotive fleet company of AK «Yakutia Railways», city of Aldan, The Republic of Sakha (Yakutia. For this purpose, three main locomotives have been examined.The object of research carried out in this paper, is a locomotive wheels tire, which is subjected to cyclic impact (dynamic loads during operation. In this regard, the need arises to determine both the strength of material in response to such shock loads and the quantitative calculation of damage accumulated therein.The accumulated fatigue damage has been attributed to one radial cross section of the wheel coming into contact with the rail once per revolution of the wheel. Consequently, in one revolution a wheel is under one loading cycle. As stated, the average mileage of locomotives to have the unacceptable damages formed on the tread surface is 12 thousand km.Test results establish that along with the high-cycle loading the shock-contact action on rail joints significantly affects the accumulation of damage in the locomotive wheels tire. The number of cycles to failure due to the formation of unacceptable damage in the locomotive wheels tire is N = 2,4×106 and 6×105 cycles, respectively, for fatigue and shock-contact loading.In general, we can say that the problem of higher intensity to form the surface damage is directly related to the operation of the locomotive wheel tire under abnormally low climatic temperatures. With decreasing ambient temperature, this element material rapidly looses its plastic properties, thereby accelerating

  7. Grinding media of Zr O2-Y2 O3

    International Nuclear Information System (INIS)

    Ussui, V.; Leitao, F.; Paschoal, J.O.A.

    1994-01-01

    This paper describes an experiment carried out to test Yttria 3 mol% stabilized zirconia as a grinding media. The Powders were produced in experimental operations of a wet chemical coprecipitation process at the Zirconium Pilot Plant in IPEN. The stabilised zirconia powders obtained were cold pressed in to cylindrical shapes and sintered at 1500 0 C for hour. The ceramics produced presented good wear resistance and were found to be efficient as zirconia powders grinding media. (author)

  8. Three omni-directional wheels control on a mobile robot

    OpenAIRE

    Ribeiro, António Fernando; Moutinho, Ivo; Silva, Pedro; Fraga, Carlos; Pereira, Nino

    2004-01-01

    Traditional two wheels differential drive normally used on mobile robots have manoeuvrability limitations and take time to sort out. Most teams use two driving wheels (with one or two cast wheels), four driving wheels and even three driving wheels. A three wheel drive with omni-directional wheel has been tried with success, and was implemented on fast moving autonomous mobile robots. This paper deals with the mathematical kinematics description of such mobile platform, it describes the advant...

  9. Simulation modeling of wheeled vehicle dynamics on the stand "Roller"

    Directory of Open Access Journals (Sweden)

    G. O. Kotiev

    2014-01-01

    Full Text Available The tests are an integral part of the wheeled vehicle design, manufacturing, and operation. The need for their conducting arises from the research and experimental activities to assess the qualitative and quantitative characteristics of the vehicles in general, as well as the individual components and assemblies. It is obvious that a variety of design features of wheeled vehicles request a development of methods both for experimental studies and for creating the original bench equipment for these purposes.The main positive feature of bench tests of automotive engineering is a broad capability to control the combinations of traction loads, speed rates, and external input conditions. Here, the steady state conditions can be used for a long time, allowing all the necessary measurements to be made, including those with video and photo recording experiment.It is known that the benefits of test "M" type (using a roller dynamometer include a wide range of test modes, which do not depend on the climatic conditions, as well as a capability to use a computer-aided testing programs. At the same time, it is known that the main drawback of bench tests of full-size vehicle is that the tire rolling conditions on the drum mismatch to the real road pavements, which are difficult to simulate on the drum surface. This problem can be solved owing to wheeled vehicle tests at the benches "Roller" to be, in efficiency, the most preferable research method. The article gives a detailed presentation of developed at BMSTU approach to its solving.Problem of simulation mathematical modeling has been solved for the vehicle with the wheel formula 8 × 8, and individual wheel-drive.The simulation results have led to the conclusion that the proposed principle to simulate a vehicle rolling on a smooth non-deformable support base using a bench " Roller " by simulation modeling is efficient.

  10. Analysis of the distribution of temperature fields in the braked railway wheel

    Directory of Open Access Journals (Sweden)

    Suchánek Andrej

    2018-01-01

    Full Text Available The article deals with detection of reduced stress in a braked railway wheel, based on thermal transient analysis on virtual models, which influence the characteristics of the railway wheels. Structural analysis was performed by means of the ANSYS Multiphysics program system package. Thermal transient analysis deals with detection of temperature fields which are a result of braking by brake block. The applied heat flux represents the heat generated by friction of brake block. It is applied to a quarter model of the wheel to speed up the calculation. This analysis simulates two braking processes with subsequent cooling. Distribution of the equivalent stress was detected in the railway wheel cross section, at selected points. The input parameters were taken from the thermal transient analysis. These equivalent stresses result from thermal load.

  11. Reaction wheels for kinetic energy storage

    Science.gov (United States)

    Studer, P. A.

    1984-11-01

    In contrast to all existing reaction wheel implementations, an order of magnitude increase in speed can be obtained efficiently if power to the actuators can be recovered. This allows a combined attitude control-energy storage system to be developed with structure mounted reaction wheels. The feasibility of combining reaction wheels with energy storage wwheels is demonstrated. The power required for control torques is a function of wheel speed but this energy is not dissipated; it is stored in the wheel. The I(2)R loss resulting from a given torque is shown to be constant, independent of the design speed of the motor. What remains, in order to efficiently use high speed wheels (essential for energy storage) for control purposes, is to reduce rotational losses to acceptable levels. Progress was made in permanent magnet motor design for high speed operation. Variable field motors offer more control flexibility and efficiency over a broader speed range.

  12. Quenching simulation of steel grinding balls

    Directory of Open Access Journals (Sweden)

    Zapata-Hernández, Oscar

    2015-09-01

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

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

    Science.gov (United States)

    ten Berge, F; te Poel, J; Ranjitkar, S; Kaidonis, J A; Lobbezoo, F; Hughes, T E; Townsend, G C

    2012-08-01

    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. © 2012 Blackwell Publishing Ltd.

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

    International Nuclear Information System (INIS)

    Deb, S.; Das, S.R.

    1995-01-01

    Commercial grade zirconia powders of mean particle size of 3.21 microns were super-ground in wet condition in alcoholic medium in a Planetary Ball-Mill for 12-hours using a zirconia pot as well as balls, in order to avoid contaminations from the grinding media. Sedigraph analysis data show the mean particle sizes within the range of 0.4 to 0.2 micron. The super-ground zirconia powders were then treated with appropriate acid and alkali solutions in order to enrich the surfaces of zirconia powders. The chemical analysis reports depict the enrichment phenomena of the processed zirconia powders. Magnesium oxide of different mole percentages (3 to 9%) have been incorporated to the above super-ground and enriched zirconia powder and green specimens were prepared by pressing with a suitable pressure of 200 MPa to yield the green compaction density of 3.06 gm/cm 3 . The compacted green specimens were sintered without pressure at 1,480 C in air followed by normal cooling. X-ray diffraction patterns of the above sintered and cooled specimens have confirmed the formation of Mg-PSZ ceramics with 40% tetragonal phase. The sintered PSZ-products have shown very good surface properties but at the cost of transverse rupture strength. The effects of grinding were observed on the above Mg-PSZ ceramics which exhibit very little change in the tetragonal phase even after 30-minutes of grinding with a 60-mesh diamond wheel at a normal pressure of 4 kg/cm 2

  15. Four-Wheel Vehicle Suspension System

    Science.gov (United States)

    Bickler, Donald B.

    1990-01-01

    Four-wheel suspension system uses simple system of levers with no compliant components to provide three-point suspension of chassis of vehicle while maintaining four-point contact with uneven terrain. Provides stability against tipping of four-point rectangular base, without rocking contact to which rigid four-wheel frame susceptible. Similar to six-wheel suspension system described in "Articulated Suspension Without Springs" (NPO-17354).

  16. Mathematical Modeling of the Braking System of Wheeled Mainline Aircraft

    Directory of Open Access Journals (Sweden)

    I. S. Shumilov

    2016-01-01

    Full Text Available The braking system of the landing gear wheels of a mainline aircraft has to meet mandatory requirements laid out in the Aviation Regulations AP-25 (Para 25.735. «Brakes and brake systems". These requirements are essential when creating the landing gear wheel brake control system (WBCS and are used as main initial data in its mathematical modeling. The WBCS is one of the most important systems to ensure the safe completion of the flight. It is a complex of devices, i.e. units (hydraulic, electrical, and mechanical, connected through piping, wiring, mechanical constraints. This complex should allow optimizing the braking process when a large number of parameters change. The most important of them are the following: runway friction coefficient (RFC, lifting force, weight and of the aircraft, etc. The main structural elements involved in braking the aircraft are: aircraft wheels with pneumatics (air tires and brake discs, WBCS, and cooling system of gear wheels when braking.To consider the aircraft deceleration on the landing run is of essence at the stage of design, development, and improvement of brakes and braking systems. Based on analysis of equation of the aircraft motion and energy balance can be determined energy loading and its basic design parameters, braking distances and braking time.As practice and analysis of energy loading show, they (brake + wheel absorb the aircraftpossessed kinetic energy at the start of braking as much as 60-70%, 70-80%, and 80-90%, respectively, under normal increased, and emergency operating conditions. The paper presents a procedure for the rapid calculation of energy loading of the brake wheel.Currently, the mainline aircrafts use mainly electrohydraulic brake systems in which there are the main, backup, and emergency-parking brake systems. All channels are equipped with automatic anti-skid systems. Their presence in the emergency (the third reserve channel significantly improves the reliability and safety of

  17. Origami Wheel Transformer: A Variable-Diameter Wheel Drive Robot Using an Origami Structure.

    Science.gov (United States)

    Lee, Dae-Young; Kim, Sa-Reum; Kim, Ji-Suk; Park, Jae-Jun; Cho, Kyu-Jin

    2017-06-01

    A wheel drive mechanism is simple, stable, and efficient, but its mobility in unstructured terrain is seriously limited. Using a deformable wheel is one of the ways to increase the mobility of a wheel drive robot. By changing the radius of its wheels, the robot becomes able to pass over not only high steps but also narrow gaps. In this article, we propose a novel design for a variable-diameter wheel using an origami-based soft robotics design approach. By simply folding a patterned sheet into a wheel shape, a variable-diameter wheel was built without requiring lots of mechanical parts and a complex assembly process. The wheel's diameter can change from 30 to 68 mm, and it is light in weight at about 9.7 g. Although composed of soft materials (fabrics and films), the wheel can bear more than 400 times its weight. The robot was able to change the wheel's radius in response to terrain conditions, allowing it to pass over a 50-mm gap when the wheel is shrunk and a 50-mm step when the wheel is enlarged.

  18. Industrial versus Laboratory Clinker Processing Using Grinding Aids (Scale Effect

    Directory of Open Access Journals (Sweden)

    Joseph Jean Assaad

    2015-01-01

    Full Text Available The evaluation of grinding aid (GA effect on clinker processing in laboratory grinding mills is relatively simple. Yet, the results obtained cannot be directly transposed to industrial mills, given the fundamentally different operational modes and grinding parameters. This paper seeks to evaluate the scale effect by comparing the results obtained from a closed-circuit tube mill operating at 90 ton/hr to those determined using a 50-liter laboratory mill. Tests results have shown that the decrease in specific energy consumption (Ec due to glycol or amine-based GA can be evaluated under laboratory conditions. However, such tests underestimate the actual performance that could be achieved in real-scale mills; the Ec reduction due to GA is around twofold higher when grinding is performed in real-scale mill. Compared to industrial tests, the cement particle size distribution curves widened and shifted towards higher diameters when grinding was performed under laboratory conditions, particularly with GA additions. This led to remarkable changes in water demand, setting time, and 1- and 28-day compressive strengths.

  19. Fatigue limit of monolithic Y-TZP three-unit-fixed dental prostheses: Effect of grinding at the gingival zone of the connector.

    Science.gov (United States)

    Amaral, Marina; Villefort, Regina F; Melo, Renata Marques; Pereira, Gabriel K R; Zhang, Yu; Valandro, Luiz Felipe; Bottino, Marco Antonio

    2017-08-01

    To determine the fatigue limits of three-unit monolithic zirconia fixed dental prosthesis (FDPs) before and after grinding of the gingival areas of connectors with diamond burs. FDPs were milled from pre-sintered blocks of zirconia simulating the absence of the first mandibular molar. Half of the specimens were subjected to grinding, simulating clinical adjustment, and all of them were subjected to glazing procedure. Additional specimens were manufactured for roughness analysis. FDPs were adhesively cemented onto glass-fiber reinforced epoxy resin abutments. Fatigue limits and standard deviations were obtained using a staircase fatigue method (n=20, 100,000 loading cycles/5Hz). The initial test load was 70% of the mean load-to-fracture (n=3) and load increments were 5% of the initial test load for both the control and ground specimens. Data were compared by Student's T-test (α≤0.05). Both the control and ground groups exhibited similar values of load-to-fracture and fatigue limits. Neither the surface treatments nor ageing affected the surface roughness of the specimens. The damage induced by grinding with fine-grit diamond bur in the gingival area of the connectors did not decrease the fatigue limit of the three-unit monolithic zirconia FDP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Greasing the Wheels of Trade

    OpenAIRE

    Hendrik P. van Dalen; Aico P. van Vuuren

    2003-01-01

    This discussion paper resulted in a publication in 'De Economist' , 2005, 153(2), 139-165. How much does a nation spend on resources to 'grease the wheels of trade'? To examine this question the Dutch economy is used as an exemplary case as the Netherlands are known as a nation of traders. This image was derived in the seventeenth century from successes in long distance trade, shipping and financial innovations. Despite its historical background in trading the potential to 'truck and barter' ...

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

    Directory of Open Access Journals (Sweden)

    Li Chuang

    2015-01-01

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

  2. Grinding, Machining Morphological Studies on C/SiC Composites

    Science.gov (United States)

    Xiao, Chun-fang; Han, Bing

    2018-05-01

    C/SiC composite is a typical material difficult to machine. It is hard and brittle. In machining, the cutting force is large, the material removal rate is low, the edge is prone to collapse, and the tool wear is serious. In this paper, the grinding of C/Si composites material along the direction of fiber distribution is studied respectively. The surface microstructure and mechanical properties of C/SiC composites processed by ultrasonic machining were evaluated. The change of surface quality with the change of processing parameters has also been studied. By comparing the performances of conventional grinding and ultrasonic grinding, the surface roughness and functional characteristics of the material can be improved by optimizing the processing parameters.

  3. Evaluation of ball and roller bearings restored by grinding

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.; Chen, S. M.

    1976-01-01

    A joint program was undertaken to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. Groups of each of these bearings were visually and dimensionally inspected for suitability for restoration. A total of 250 bearings were restored by grinding. Of this number, 30 bearings from each type were endurance tested to a TBO of 1600 hours. No bearing failures occurred related to the restoration by grinding process. The two bearing failures which occurred were due to defective rolling elements and were typical of those which may occur in new bearings. The restorable component yield to the three groups was in excess of 90 percent.

  4. Design and development of automatic sharia compliant wheelchair wheels cleaner

    Science.gov (United States)

    Shaari, Muhammad Farid; Rasli, Ibrahim Ismail Mohammad; Jamaludin, M. Z. Z. Wan; Isa, W. A. Mohamad; M., H.; Rashid, A. H. Abdul

    2017-04-01

    Sharia compliant wheelchair wheel cleaner was developed in order to assist the muslim Person with Disabilities (PWD) to pray in the mosque without leaving their wheelchair because of the filthy wheels. Though there are many wheelchair wheel cleaning system in the market, it is very rare to find sharia compliant cleaning system that applies sertu concept which is one of the cleaning and purification technique in Islamic practice. The sertu concept is based on 6:1 ratio that refers to the six times pipe water cleaning and one time soiled water cleaning. The development process consists of design stage, fabrication and system installation stage and followed by testing stage. During the design stage, the proposed prototype underwent design brainstorming, operation programming and structural simulation analysis. Once fabricated, the cleaner prototype underwent was tested. The results showed that the prototype can cater load up to 100kg with 1.31×10-6 mm shaft bending displacement. The water ejection timing varied approximately 3% compared to the program.

  5. Optimal Electrical Energy Slewing for Reaction Wheel Spacecraft

    Science.gov (United States)

    Marsh, Harleigh Christian

    The results contained in this dissertation contribute to a deeper level of understanding to the energy required to slew a spacecraft using reaction wheels. This work addresses the fundamental manner in which spacecrafts are slewed (eigenaxis maneuvering), and demonstrates that this conventional maneuver can be dramatically improved upon in regards to reduction of energy, dissipative losses, as well as peak power. Energy is a fundamental resource that effects every asset, system, and subsystem upon a spacecraft, from the attitude control system which orients the spacecraft, to the communication subsystem to link with ground stations, to the payloads which collect scientific data. For a reaction wheel spacecraft, the attitude control system is a particularly heavy load on the power and energy resources on a spacecraft. The central focus of this dissertation is reducing the burden which the attitude control system places upon the spacecraft in regards to electrical energy, which is shown in this dissertation to be a challenging problem to computationally solve and analyze. Reducing power and energy demands can have a multitude of benefits, spanning from the initial design phase, to in-flight operations, to potentially extending the mission life of the spacecraft. This goal is approached from a practical standpoint apropos to an industry-flight setting. Metrics to measure electrical energy and power are developed which are in-line with the cost associated to operating reaction wheel based attitude control systems. These metrics are incorporated into multiple families of practical high-dimensional constrained nonlinear optimal control problems to reduce the electrical energy, as well as the instantaneous power burdens imposed by the attitude control system upon the spacecraft. Minimizing electrical energy is shown to be a problem in L1 optimal control which is nonsmooth in regards to state variables as well as the control. To overcome the challenge of nonsmoothness, a

  6. Study on the Rollover Characteristic of In-Wheel-Motor-Driven Electric Vehicles Considering Road and Electromagnetic Excitation

    OpenAIRE

    Di Tan; Haitao Wang; Qiang Wang

    2016-01-01

    For in-wheel-motor-driven electric vehicles, the motor is installed in the wheel directly. Tyre runout and uneven load can cause magnet gap deformation in the motor, which will produce electromagnetic forces that further influence the vehicle rollover characteristics. To study the rollover characteristics, a verified 16-degree-of-freedom rollover dynamic model is introduced. Next, the vehicle rollover characteristics both with and without electromagnetic force are analyzed under conditions of...

  7. Meals on Wheels Association of America

    Science.gov (United States)

    ... Meals About Meals on Wheels Get Started The Issue The Problem & Our Solution Meals on Wheels Health Facts & Resources Senior Facts Map State Fact Sheets Research More Than a Meal Pilot Research Study Medicare Claims Analyses Policy Myths Hunger in Older Adults Take Action Volunteer Advocate #SAVELUNCH ...

  8. A Full Disturbance Model for Reaction Wheels

    NARCIS (Netherlands)

    Le, M.P.; Ellenbroek, Marcellinus Hermannus Maria; Seiler, R; van Put, P.; Cottaar, E.J.E.

    2014-01-01

    Reaction wheels are rotating devices used for the attitude control of spacecraft. However, reaction wheels also generate undesired disturbances in the form of vibrations, which may have an adverse effect on the pointing accuracy and stability of spacecraft (optical) payloads. A disturbance model for

  9. Assessment of a Boat Fractured Steering Wheel

    Directory of Open Access Journals (Sweden)

    Vukelic Goran

    2016-09-01

    Full Text Available During regular use of the steering wheel mounted on a boat, two cracks emanating from a fastener hole were noticed which, consequently, caused final fracture of the wheel. To determine the behavior of a boat steering wheel with cracks present, assessment of a fractured wheel was performed. Torque moments of the fasteners were measured prior to removing the steering wheel from the boat. Visual and dye penetrant inspection followed along with the material detection. Besides using experimental procedures, assessment of the fractured wheel was performed using finite element analysis, i.e. stress intensity factor values were numerically determined. Variation of stress intensity factor with crack length is presented. Possible causes of crack occurrence are given and they include excessive values of fastener torque moments coupled with fretting between fastener and fastener hole that was poorly machined. Results obtained by this assessment can be taken for predicting fracture behavior of a cracked steering wheel and as a reference in the design, mounting and exploitation process of steering wheels improving that way their safety in transportation environment.

  10. Riding the Ferris Wheel: A Sinusoidal Model

    Science.gov (United States)

    Mittag, Kathleen Cage; Taylor, Sharon E.

    2011-01-01

    When thinking of models for sinusoidal waves, examples such as tides of the ocean, daily temperatures for one year in your town, light and sound waves, and certain types of motion are used. Many textbooks [1, p. 222] also present a "Ferris wheel description problem" for students to work. This activity takes the Ferris wheel problem out of the…

  11. The Ferris Wheel and Justifications of Curvature

    Science.gov (United States)

    Stevens, Irma E.; Moore, Kevin C.

    2016-01-01

    This report discusses the results of semi-structured clinical interviews with ten prospective secondary mathematics teachers who were provided with dynamic images of Ferris wheels. We asked the students to graph the relationship between the distance a rider traveled around the Ferris wheel and the height of the rider from the ground. We focus on…

  12. 29 CFR 1915.134 - Abrasive wheels.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Abrasive wheels. 1915.134 Section 1915.134 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... wheels shall fit freely on the spindle and shall not be forced on. The spindle nut shall be tightened...

  13. Dynamic and Acoustic Characterisation of Automotive Wheels

    Directory of Open Access Journals (Sweden)

    Francesca Curà

    2004-01-01

    Full Text Available The subject of this paper is the dynamic and acoustic characterisation of an automotive wheel. In particular, an experimental research activity previously performed by the authors about the dynamic behaviour of automotive wheels has been extended to the acoustic field.

  14. Dry grinding of talc in a stirred ball mill

    Directory of Open Access Journals (Sweden)

    Cayirli Serkan

    2016-01-01

    Full Text Available The aim of this work was to investigate micro fine size dry grindability of talc in a stirred ball mill. The effects of various parameters such as grinding time, stirrer speed, powder filling ratio and ball filling ratio were investigated. Alumina balls were used as grinding media. Experiments were carried out using the 24 full factorial design. The main and interaction effects were evaluated using the Yates method. Test results were evaluated on the basis of product size and surface area.

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

    International Nuclear Information System (INIS)

    Ervanne, H.; Hakanen, M.

    2007-04-01

    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.)

  16. A novel dual motor drive system for three wheel electric vehicles

    Science.gov (United States)

    Panmuang, Piyapat; Thongsan, Taweesak; Suwapaet, Nuchida; Laohavanich, Juckamass; Photong, Chonlatee

    2018-03-01

    This paper presents a novel dual motor drive system used for three wheel electric vehicles that have one free wheel at the front and two wheels with a drive system at the end of the vehicles. A novel dual motor drive system consists of two identical DC motors that are independently controlled by its speed-torque controller. Under light load conditions, only one of the DC motors will operate around it rated whilst under hard load conditions both of the DC motors will operate. With this drive system, the motors will operate only at its high performance at rated or else no operate to retain longer lifetime. The simulated results for the Skylab three wheel electric vehicle prototype with 8kW at full load (high torque, low speed) and around 4kW at light/normal operating loads (regular speed-torque) showed that the proposed system provides better dynamic responses with faster overshoot current/voltage recovery time, has lower investment costs, has longer lifetime of the motors and allows the motors to always operate at their high performance and thus achieve more cost effective system compared to a single motor drive system with 8kW DC motors.

  17. The inertial effect of acceleration fields on a self-decoupled wheel force transducer

    Directory of Open Access Journals (Sweden)

    Lihang Feng

    Full Text Available AbstractWheel force transducer (WFT is a tool which can measure the three-axis forces and three-axis torques applied to the wheel in vehicle testing applications. However, the transducer is generally mounted on the wheel of a moving vehicle, when abruptly accelerating or braking, the mass/inertia of the transducer itself has extra effects on the sensor response so that inertia/mass loads will be detected and coupled into the signal outputs. This is the inertia coupling effect that decreases the sensor accuracy and should be avoided. In this paper, the inertia coupling problem induced by six dimensional accelerations is investigated for a universal WFT. Inertia load distribution of the WFT is solved based on the principle of equivalent mass and rotary inertia firstly, thus then its impact can be identified with the theoretical derivation. FEM simulation and experimental verification are performed as well. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear respectively. The relative errors are acceptable within less than 5% and the maximum impact of inertia loads on the signal output is about 1.5% in the measuring range.

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

    Directory of Open Access Journals (Sweden)

    G. O. Magomedov

    2013-01-01

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

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

    OpenAIRE

    G. O. Magomedov; M. K. Sadigova; S. I. Lukina; V. Y. Kustov

    2013-01-01

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

  20. Modelling of a mecanum wheel taking into account the geometry of road rollers

    Science.gov (United States)

    Hryniewicz, P.; Gwiazda, A.; Banaś, W.; Sękala, A.; Foit, K.

    2017-08-01

    During the process planning in a company one of the basic factors associated with the production costs is the operation time for particular technological jobs. The operation time consists of time units associated with the machining tasks of a workpiece as well as the time associated with loading and unloading and the transport operations of this workpiece between machining stands. Full automation of manufacturing in industry companies tends to a maximal reduction in machine downtimes, thereby the fixed costs simultaneously decreasing. The new construction of wheeled vehicles, using Mecanum wheels, reduces the transport time of materials and workpieces between machining stands. These vehicles have the ability to simultaneously move in two axes and thus more rapid positioning of the vehicle relative to the machining stand. The Mecanum wheel construction implies placing, around the wheel free rollers that are mounted at an angle 450, which allow the movement of the vehicle not only in its axis but also perpendicular thereto. The improper selection of the rollers can cause unwanted vertical movement of the vehicle, which may cause difficulty in positioning of the vehicle in relation to the machining stand and the need for stabilisation. Hence the proper design of the free rollers is essential in designing the whole Mecanum wheel construction. It allows avoiding the disadvantageous and unwanted vertical vibrations of a whole vehicle with these wheels. In the article the process of modelling the free rollers, in order to obtain the desired shape of unchanging, horizontal trajectory of the vehicle is presented. This shape depends on the desired diameter of the whole Mecanum wheel, together with the road rollers, and the width of the drive wheel. Another factor related with the curvature of the trajectory shape is the length of the road roller and its diameter decreases depending on the position with respect to its centre. The additional factor, limiting construction of

  1. Assessing the influence of wheel defects of a rolling stockon railway tracks

    Directory of Open Access Journals (Sweden)

    Loktev Aleksey Alekseevich

    2015-05-01

    Full Text Available Transfer of the load from the wheels on the rail occurs at a very small area compared with the size of the wheels and rails. The materials near this site have a very large voltage. Determination of contact stresses is complicated by the fact that the magnitude of these stresses in the rails under actually revolving wheel load exceeds the yield and compressive strength of modern rail steel. We should note that the metal of the rail head, experiencing contact stresses, especially when the location of the pads is closer to the middle of the rail head, works in the conditions close to the compression conditions, and therefore can withstand higher voltage without plastic deformation than the standard compressible sample. But, as a rule, the observed hardening of the metal in the zone of contact stresses and lapping at the edges of the rail head indicates the presence of plastic deformation and, consequently, higher stresses in the wheel-rail contact zone than the yield strength of the metal rail even in the conditions of its operation in the rail head.The use of the design equations derived on the basis of the Hertz theory for metal behavior in elastic stage, is valid. The reason is that each individual dynamic application of wheel loads on the rail is very short, and the residual plastic deformation from the individual loads of the pair of wheels on the rail is actually small. This elastic-plastic deformation of the rail becomes visible as a result of gradual gaining of a missed tonnage of rails and wheels respectively. Irregularities on the running surface of the wheels are of two types. The most common are the so-called continuous bumps on the wheel, when due to the uneven wear of rail the original shape of the wheel across the tread surface distorts. But nowadays, more and more often there occur isolated smooth irregularities of the wheel pairs, due to the increased wear of the wheel because of the stopping and blocking of wheels of the vehicles

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

    International Nuclear Information System (INIS)

    Tolino, R.W.

    1988-01-01

    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

  3. Optimization of wheel-rail interface friction using top-of-rail friction modifiers: State of the art

    Science.gov (United States)

    Khan, M. Roshan; Dasaka, Satyanarayana Murty

    2018-05-01

    High Speed Railways and Dedicated Freight Corridors are the need of the day for fast and efficient transportation of the ever growing population and freight across long distances of travel. With the increase in speeds and axle loads carried by these trains, wearing out of rails and train wheel sections are a common issue, which is due to the increase in friction at the wheel-rail interfaces. For the cases where the wheel-rail interface friction is less than optimum, as in case of high speed trains with very low axle loads, wheel-slips are imminent and loss of traction occurs when the trains accelerate rapidly or brake all of a sudden. These vast variety of traction problems around the wheel-rail interface friction need to be mitigated carefully, so that the contact interface friction neither ascents too high to cause material wear and need for added locomotive power, nor be on the lower side to cause wheel-slips and loss of traction at high speeds. Top-of-rail friction modifiers are engineered surface coatings applied on top of rails, to maintain an optimum frictional contact between the train wheels and the rails. Extensive research works in the area of wheel-rail tribology have revealed that the optimum frictional coefficients at wheel-rail interfaces lie at a value of around 0.35. Application of top-of-rail (TOR) friction modifiers on rail surfaces add an extra layer of material coating on top of the rails, with a surface frictional coefficient of the desired range. This study reviews the common types of rail friction modifiers, the methods for their application, issues related with the application of friction modifiers, and a guideline on selection of the right class of coating material based on site specific requirements of the railway networks.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  5. Ultrasonic Vibration Assisted Grinding of Bio-ceramic Materials: Modeling, Simulation, and Experimental Investigations on Edge Chipping

    Science.gov (United States)

    Tesfay, Hayelom D.

    Bio-ceramics are those engineered materials that find their applications in the field of biomedical engineering or medicine. They have been widely used in dental restorations, repairing bones, joint replacements, pacemakers, kidney dialysis machines, and respirators. etc. due to their physico-chemical properties, such as excellent corrosion resistance, good biocompatibility, high strength and high wear resistance. Because of their inherent brittleness and hardness nature they are difficult to machine to exact sizes and dimensions. Abrasive machining processes such as grinding is one of the most widely used manufacturing processes for bioceramics. However, the principal technical challenge resulted from these machining is edge chipping. Edge chipping is a common edge failure commonly observed during the machining of bio-ceramic materials. The presence of edge chipping on bio-ceramic products affects dimensional accuracy, increases manufacturing cost, hider their industrial applications and causes potential failure during service. To overcome these technological challenges, a new ultrasonic vibration-assisted grinding (UVAG) manufacturing method has been developed and employed in this research. The ultimate aim of this study is to develop a new cost-effective manufacturing process relevant to eliminate edge chippings in grinding of bio-ceramic materials. In this dissertation, comprehensive investigations will be carried out using experimental, theoretical, and numerical approaches to evaluate the effect of ultrasonic vibrations on edge chipping of bioceramics. Moreover, effects of nine input variables (static load, vibration frequency, grinding depth, spindle speed, grinding distance, tool speed, grain size, grain number, and vibration amplitude) on edge chipping will be studied based on the developed models. Following a description of previous research and existing approaches, a series of experimental tests on three bio-ceramic materials (Lava, partially fired Lava

  6. Investigation of glycerol polymerization in the clinker grinding process

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Michelle K. McGinn

    2010-05-01

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

  8. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-01

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

  9. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    International Nuclear Information System (INIS)

    Poffo, C.M.; Lima, J.C. de; Souza, S.M.; Triches, D.M.; Grandi, T.A.; Biasi, R.S. de

    2011-01-01

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

  10. Grinding induced martensite on the surface of rails

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  11. Grinding machine: Friend or Foe | Adigun | West African Journal of ...

    African Journals Online (AJOL)

    Few cases of traumatic loses of the external genitalia have been reported in this part of the world. In a developing country like ours, grinding machines are commonly being used by the people for domestic purposes. Children in their mid fifteens are usually employed to man and operate the machine without proper training ...

  12. Contact and Non-contact Measurements of Grinding Pins

    Directory of Open Access Journals (Sweden)

    Magdziak Marek

    2015-01-01

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

  13. development and evaluation of a drill re-grinding fixture

    African Journals Online (AJOL)

    user

    as work holding device for re-grinding drills bits with diameter of at least 4.5 mm and above without ... cause normal stress to exceed yield stress of the material. ..... Institute of Rese r h nd sy hology”, Vol , pp 7 ... America Patent 10052968.

  14. Automatic programming of grinding robot restoration of contours

    Directory of Open Access Journals (Sweden)

    Are Willersrud

    1995-07-01

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

  15. Automatic programming of grinding robot restoration of contours

    OpenAIRE

    Are Willersrud; Fred Godtliebsen; Trygve Thomessen

    1995-01-01

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

  16. Development of the pellet grinding and inspection system

    International Nuclear Information System (INIS)

    Yamaguchi, Toshihiro; Kawasaki, Takao; Inui, Toshihiko; Yamada, Hiroyuki.

    1996-01-01

    The pellet grinding and inspection system is the facility of producing the MOX fuel for FBRs, and it was delivered in March, 1996 to the No. 3 Development Office of the plutonium fuel shop in Tokai of Power Reactor and Nuclear Fuel Development Corporation. This facility realized the high speed processing using the compact facility by combining the grinding of pellets, the inspection of outer density and appearance, the rationalization of the facility and the high performance automation equipment. The production processes of MOX comprise the processes of powder, sinter, finish and inspection, fabrication and assembling. The requirement for developing these facilities is shown. The features of this pellet grinding and inspection system are the compact facility by the combination of functions, high speed processing, the reduction of holdup in processes and the improvement of maintenance. These features are explained. The main components are simple sorting equipment, grinder, grinding dust recovering equipment, outside diameter and density sorting equipment and appearance inspection equipment. The constitution and the main functions of the control facility are described. The operational process is explained. (K.I.)

  17. Controlled wear of vitrified abrasive materials for precision grinding ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    2Machining Research Group, Department of Engineering, University of ... ods are applied to analyse the cutting mechanism in grinding. .... (d) Chemical reaction between abrasive and workpiece material at elevated temperatures ... most common method used for measuring wear flat area employs an optical, or an electron.

  18. short communication simple grinding-induced reactions of 2 ...

    African Journals Online (AJOL)

    Preferred Customer

    benzoxazine moiety features in the natural product terresoxazine isolated from Tribulus terrestris [12] and many other bioactive molecules [13-15]. Although several methods for the preparation of 1,3-oxazine derivatives have previously been reported [16-21] few have been focused on the solid-solid or solid-liquid grinding ...

  19. Minisatellite Attitude Guidance Using Reaction Wheels

    Directory of Open Access Journals (Sweden)

    Ion STROE

    2015-06-01

    Full Text Available In a previous paper [2], the active torques needed for the minisatellite attitude guidance from one fixed attitude posture to another fixed attitude posture were determined using an inverse dynamics method. But when considering reaction/momentum wheels, instead of this active torques computation, the purpose is to compute the angular velocities of the three reaction wheels which ensure the minisatellite to rotate from the initial to the final attitude. This paper presents this computation of reaction wheels angular velocities using a similar inverse dynamics method based on inverting Euler’s equations of motion for a rigid body with one fixed point, written in the framework of the x-y-z sequence of rotations parameterization. For the particular case A=B not equal C of an axisymmetric minisatellite, the two computations are compared: the active torques computation versus the computation of reaction wheels angular velocities ̇x , ̇y and ̇z. An interesting observation comes out from this numerical study: if the three reaction wheels are identical (with Iw the moment of inertia of one reaction wheel with respect to its central axis, then the evolutions in time of the products between Iw and the derivatives of the reaction wheels angular velocities, i.e. ̇ , ̇ and ̇ remain the same and do not depend on the moment of inertia Iw.

  20. Determination of vertical pressures on running wheels of freight trolleys of bridge type cranes

    Science.gov (United States)

    Goncharov, K. A.; Denisov, I. A.

    2018-03-01

    The problematic issues of the design of the bridge-type trolley crane, connected with ensuring uniform load distribution between the running wheels, are considered. The shortcomings of the existing methods of calculation of reference pressures are described. The results of the analytical calculation of the pressure of the support wheels are compared with the results of the numerical solution of this problem for various schemes of trolley supporting frames. Conclusions are given on the applicability of various methods for calculating vertical pressures, depending on the type of metal structures used in the trolley.

  1. Low Voltage Power for the ATLAS New Small Wheel Muon Detector

    CERN Document Server

    Edgar, Ryan Christopher; The ATLAS collaboration

    2016-01-01

    The New Small Wheel (NSW) is an upgrade for enhanced triggering and reconstruction of muons in the forward region of the ATLAS detector at CERN's Large Hadron Collider. The large LV power demands necessitate a point-of-load architecture with on-detector power conversion. We present final results from an extensive campaign to test commercial power devices in radiation and magnetic fields, and describe an alternate solution based on a radiation-hard power conversion ASIC (the FEAST) produced by CERN microelectronics. We detail the challenges and solutions in integrating this device into the New Small Wheel, and outline the full resulting power system.

  2. Grinding damage assessment for CAD-CAM restorative materials.

    Science.gov (United States)

    Curran, Philippe; Cattani-Lorente, Maria; Anselm Wiskott, H W; Durual, Stéphane; Scherrer, Susanne S

    2017-03-01

    To assess surface/subsurface damage after grinding with diamond discs on five CAD-CAM restorative materials and to estimate potential losses in strength based on crack size measurements of the generated damage. The materials tested were: Lithium disilicate (LIT) glass-ceramic (e.max CAD), leucite glass-ceramic (LEU) (Empress CAD), feldspar ceramic (VM2) (Vita Mark II), feldspar ceramic-resin infiltrated (EN) (Enamic) and a composite reinforced with nano ceramics (LU) (Lava Ultimate). Specimens were cut from CAD-CAM blocs and pair-wise mirror polished for the bonded interface technique. Top surfaces were ground with diamond discs of respectively 75, 54 and 18μm. Chip damage was measured on the bonded interface using SEM. Fracture mechanics relationships were used to estimate fracture stresses based on average and maximum chip depths assuming these to represent strength limiting flaws subjected to tension and to calculate potential losses in strength compared to manufacturer's data. Grinding with a 75μm diamond disc induced on a bonded interface critical chips averaging 100μm with a potential strength loss estimated between 33% and 54% for all three glass-ceramics (LIT, LEU, VM2). The softer materials EN and LU were little damage susceptible with chips averaging respectively 26μm and 17μm with no loss in strength. Grinding with 18μm diamond discs was still quite detrimental for LIT with average chip sizes of 43μm and a potential strength loss of 42%. It is essential to understand that when grinding glass-ceramics or feldspar ceramics with diamond discs surface and subsurface damage are induced which have the potential of lowering the strength of the ceramic. Careful polishing steps should be carried out after grinding especially when dealing with glass-ceramics. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Li, Jia; Fang, Qihong; Zhang, Liangchi; Liu, Youwen

    2015-01-01

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

  4. A rotating target wheel system for gammasphere

    International Nuclear Information System (INIS)

    Greene, J. P.

    1999-01-01

    A description is given for a low-mass, rotating target wheel to be used within the Gammasphere target chamber. This system was developed for experiments employing high beam currents in order to extend lifetimes of targets using low-melting point target material. The design is based on a previously successful implementation of rotating target wheels for the Argonne Positron Experiment (APEX) as well as the Fragment Mass Analyser (FMA) at ATLAS (Argonne Tandem Linac Accelerator System). A brief history of these rotating target wheel systems is given as well as a discussion on target preparation and performance

  5. Why Animals Run on Legs, Not on Wheels.

    Science.gov (United States)

    Diamond, Jared

    1983-01-01

    Speculates why animals have not developed wheels in place of inefficient legs. One study cited suggests three reasons why animals are better off without wheels: wheels are efficient only on hard surfaces, limitation of wheeled motion due to vertical obstructions, and the problem of turning in spaces cluttered with obstacles. (JN)

  6. 49 CFR 230.113 - Wheels and tire defects.

    Science.gov (United States)

    2010-10-01

    ... tires may not have a seam running lengthwise that is within 33/4 inches of the flange. (g) Worn flanges... 49 Transportation 4 2010-10-01 2010-10-01 false Wheels and tire defects. 230.113 Section 230.113... Tenders Wheels and Tires § 230.113 Wheels and tire defects. Steam locomotive and tender wheels or tires...

  7. Development and validation of a new kind of coupling element for wheel-hub motors

    Science.gov (United States)

    Perekopskiy, Sergey; Kasper, Roland

    2018-05-01

    For the automotive industry, electric powered vehicles are becoming an increasingly relevant factor in the competition against climate change. Application of one special example - a wheel-hub motor, for electric powered vehicle can support this challenge. Patented slotless air gap winding invented at the chair of mechatronics of the Otto von Guericke University Magdeburg has great application potential in constantly growing e-mobility field, especially for wheel-hub motors based on this technology due to its advantages, such as a high gravimetric power density and high efficiency. However, advantages of this technology are decreased by its sensibility to the loads out of driving maneuvers by dimensional variations of air gap consistency. This article describes the development and validation of a coupling element for the designed wheel-hub motor. To find a suitable coupling concept first the assembly structure of the motor was analyzed and developed design of the coupling element was checked. Based on the geometry of the motor and wheel a detailed design of the coupling element was generated. The analytical approach for coupling element describes a potential of the possible loads on the coupling element. The FEM simulation of critical load cases for the coupling element validated results of the analytical approach.

  8. Effect of Grinding and Resintering on the Fatigue Limit and Surface Characterization of a Y-TZP Ceramic.

    Science.gov (United States)

    Polli, Gabriela Scatimburgo; Hatanaka, Gabriel Rodrigues; Abi-Rached, Filipe de Oliveira; Pinelli, Lígia Antunes Pereira; Góes, Márcio de Sousa; Cesar, Paulo Francisco; Reis, José Maurício Dos Santos Nunes

    2016-01-01

    This study evaluated the effect of grinding protocols and resintering on flexural fatigue limit and surface characterization of LavaTM Y-TZP. Bar-shaped specimens (20×4.0×1.2 mm, n=40; 20×4.0×1.5 mm, n=80) were obtained. Half of the thinner specimens (1.2 mm) constituted the as-sintered group (AS), while the thicker ones (1.5 mm) were ground with diamond burs under irrigation (WG) or not (G). The other half of thinner and half of ground specimens were resintered (1000 ºC, 30 min), forming the groups ASR, WGR and GR. Fatigue limit (500,000 cycles, 10 Hz) was evaluated by staircase method in a 4-point flexural fixture. Data were analyzed by 2-way ANOVA and Tukey's test (α=0.05). Surface topography (n=3) and fracture area (n=3) were evaluated by SEM. X-ray diffraction data (n=1) was analyzed by Rietveld refinement. ANOVA revealed significant differences (pgrinding protocol, resintering and their interaction. Grinding increased the fatigue limit of non-resintered groups. There was no significant difference among the resintered groups. Resintering significantly increased the fatigue limit of the AS group only. Both protocols created evident grooves on zirconia surface. The failures initiated at the tensile side of all specimens. The percentages (wt%) of monoclinic phase were AS (8.6), ASR (1.2), G (1.8), GR (0.0), WG (8.2), WGR (0.0) before, and AS (7.4), ASR (6.5), G (3.2), GR (0.2), WG (4.6), WGR (1.1) after cyclic loading. Grinding increased the fatigue limit of non-resintered Y-TZP and formed evident grooves on its surface. Resintering provided significant increase in the fatigue limit of as-sintered specimens. In general, grinding and resintering decreased or zeroed the monoclinic phase.

  9. Inertia coupling analysis of a self-decoupled wheel force transducer under multi-axis acceleration fields.

    Directory of Open Access Journals (Sweden)

    Lihang Feng

    Full Text Available Wheel force transducer (WFT, which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.

  10. Inertia coupling analysis of a self-decoupled wheel force transducer under multi-axis acceleration fields.

    Science.gov (United States)

    Feng, Lihang; Lin, Guoyu; Zhang, Weigong; Dai, Dong

    2015-01-01

    Wheel force transducer (WFT), which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.

  11. Reinventing the wheel: comparison of two wheel cage styles for assessing mouse voluntary running activity.

    Science.gov (United States)

    Seward, T; Harfmann, B D; Esser, K A; Schroder, E A

    2018-04-01

    Voluntary wheel cage assessment of mouse activity is commonly employed in exercise and behavioral research. Currently, no standardization for wheel cages exists resulting in an inability to compare results among data from different laboratories. The purpose of this study was to determine whether the distance run or average speed data differ depending on the use of two commonly used commercially available wheel cage systems. Two different wheel cages with structurally similar but functionally different wheels (electromechanical switch vs. magnetic switch) were compared side-by-side to measure wheel running data differences. Other variables, including enrichment and cage location, were also tested to assess potential impacts on the running wheel data. We found that cages with the electromechanical switch had greater inherent wheel resistance and consistently led to greater running distance per day and higher average running speed. Mice rapidly, within 1-2 days, adapted their running behavior to the type of experimental switch used, suggesting these running differences are more behavioral than due to intrinsic musculoskeletal, cardiovascular, or metabolic limits. The presence of enrichment or location of the cage had no detectable impact on voluntary wheel running. These results demonstrate that mice run differing amounts depending on the type of cage and switch mechanism used and thus investigators need to report wheel cage type/wheel resistance and use caution when interpreting distance/speed run across studies. NEW & NOTEWORTHY The results of this study highlight that mice will run different distances per day and average speed based on the inherent resistance present in the switch mechanism used to record data. Rapid changes in running behavior for the same mouse in the different cages demonstrate that a strong behavioral factor contributes to classic exercise outcomes in mice. Caution needs to be taken when interpreting mouse voluntary wheel running activity to

  12. Performing in-feed type centerless grinding process on a surface grinder

    International Nuclear Information System (INIS)

    Xu, W.; Wu, Y.; Sato, T.; Lin, W.

    2011-01-01

    In our previous study, a new centerless grinding method using surface grinder was proposed. In this method, centerless grinding operations are performed by installing a compact centerless grinding unit, consisting mainly of an ultrasonic elliptic-vibration shoe, a blade and their respective holders, on the worktable of a surface grinder. During grinding, the cylindrical workpiece is held on the ultrasonic shoe and the blade, and its rotational motion is controlled by the elliptic motion of the shoe end-face. An actual unit had been produced and its performance in tangential-feed type centerless grinding using a surface grinder had been confirmed in the previous workd. In this paper, the performance of the grinding unit in in-feed centerless grinding operation was confirmed, and the effects of the main process parameter, i.e., eccentric angle, on the workpiece roundness was investigated experimentally. The obtained results showed that: (1) the centerless grinding unit performed well in in-feed type centerless grinding; (2) the eccentric angle affects roundness significantly, and its optimal angle is 6 deg.; (3) the workpiece roundness can be further improved by varying the eccentric angle during grinding, and the final roundness reached 0.65 μm after grinding as the eccentric angle varied from 9 deg. to 6 deg. and to 3 deg.

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

    Science.gov (United States)

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

    2017-12-01

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

  14. Flotation performances and surface properties of chalcopyrite with xanthate collector added before and after grinding

    Science.gov (United States)

    Peng, Huiqing; Wu, Di; Abdelmonem, Mohamed

    In this study, effects of the collector added before grinding and after grinding on the subsequent flotation and mineral surface properties were investigated. The pH was controlled at 10 during the grinding and flotation processes opened to the atmosphere. With enough amounts of sodium butyl xanthate addition, adding the collector before grinding recovered more chalcopyrite than adding it after grinding in single mineral flotation. The Eh of each ground pulp before and after conditioning were measured and it was found that adding collector before grinding obtained higher and relatively suitable pulp potential for chalcopyrite flotation. Particle size analyses of the flotation products indicate that the different flotation recoveries occurred due to the different flotation losses in fine particles (flotation feedings and found that more carbon and oxygen, and less iron were remained on mineral surfaces when the collector was added before grinding, due to the higher collector adsorption capacity, larger free oxygen adsorbance and less iron oxide/hydroxide species.

  15. An Ultrasonic Wheel-Array Probe

    Science.gov (United States)

    Drinkwater, B. W.; Brotherhood, C. J.; Freemantle, R. J.

    2004-02-01

    This paper describes the development and modeling of an ultrasonic array wheel probe scanning system. The system operates at 10 MHz using a 64 element array transducer which is 50 mm in length and located in a fluid filled wheel. The wheel is coupled to the test structure dry, or with a small amount of liquid couplant. When the wheel is rolled over the surface of the test structure a defect map (C-Scan) is generated in real-time. The tyre is made from a soft, durable polymer which has very little acoustic loss. Two application studies are presented; the inspection of sealant layers in an aluminum aircraft wing structure and the detection of embedded defects in a thick section carbon composite sample.

  16. Multiple Wheel Throwing: And Chess Sets.

    Science.gov (United States)

    Sapiro, Maurice

    1978-01-01

    A chess set project is suggested to teach multiple throwing, the creation on a potter's wheel of several pieces of similar configuration. Processes and finished sets are illustrated with photographs. (SJL)

  17. UT Biomedical Informatics Lab (BMIL) probability wheel

    Science.gov (United States)

    Huang, Sheng-Cheng; Lee, Sara; Wang, Allen; Cantor, Scott B.; Sun, Clement; Fan, Kaili; Reece, Gregory P.; Kim, Min Soon; Markey, Mia K.

    A probability wheel app is intended to facilitate communication between two people, an "investigator" and a "participant", about uncertainties inherent in decision-making. Traditionally, a probability wheel is a mechanical prop with two colored slices. A user adjusts the sizes of the slices to indicate the relative value of the probabilities assigned to them. A probability wheel can improve the adjustment process and attenuate the effect of anchoring bias when it is used to estimate or communicate probabilities of outcomes. The goal of this work was to develop a mobile application of the probability wheel that is portable, easily available, and more versatile. We provide a motivating example from medical decision-making, but the tool is widely applicable for researchers in the decision sciences.

  18. Electrostatic Spectrometer for Mars Rover Wheel

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop a simple electrostatic spectrometer that can be mounted on the wheels of a Mars rover to continuously and unobtrusively determine the mineral composition and...

  19. Benefits of magnesium wheels for consumer cars

    Science.gov (United States)

    Frishfelds, Vilnis; Timuhins, Andrejs; Bethers, Uldis

    2018-05-01

    Advantages and disadvantages of magnesium wheels are considered based on a mechanical model of a car. Magnesium wheels are usually applied to racing cars as they provide slightly better strength/weight ratio than aluminum alloys. Do they provide notable benefits also for the everyday user when the car speeds do not exceed allowed speed limit? Distinct properties of magnesium rims are discussed. Apart from lighter weight of magnesium alloys, they are also good in dissipating the energy of vibrations. The role of energy dissipation in the rim of a wheel is estimated by a quarter car model. Improvements to safety by using the magnesium wheels are considered. Braking distance and responsiveness of the car is studied both with and without using an Anti Blocking System (ABS). Influence of rim weight on various handling parameters of the car is quantitatively tested.

  20. Impact of overweight vehicles (with heavy axle loads) on bridge deck deterioration.

    Science.gov (United States)

    2012-03-01

    Bridge deck slabs develop compressive stresses from global flexural deformation and locally from high-level : wheel loads when it is subjected to overweight trucks. This study quantified the impact of overweight vehicles : with heavy axle loads on br...

  1. A Nontoxic Barlow's Wheel

    Science.gov (United States)

    Daffron, John A.; Greenslade, Thomas B., Jr.

    2015-01-01

    Barlow's wheel has been a favorite demonstration since its invention by Peter Barlow (1776-1862) in 1822. In the form shown in Fig. 1, it represents the first electric motor. The interaction between the electric current passing from the axle of the wheel to the rim and the magnetic field produced by the U-magnet produces a torque that turns…

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

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2008-05-01

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

  3. Relationships among the contact patch length and width, the tire deflection and the rolling resistance of a free-running wheel in a soil bin facility

    Energy Technology Data Exchange (ETDEWEB)

    Tomaraee, P.; Mardani, A.; Mohebbi, A.; Taghavifar, H.

    2015-07-01

    Qualitative and quantitative analysis of contact patch length-rolling resistance, contact patch width-rolling resistance and tire deflection-rolling resistance at different wheel load and inflation pressure levels is presented. The experiments were planned in a randomized block design and were conducted in the controlled conditions provided by a soil bin environment utilizing a well-equipped single wheel-tester of Urmia University, Iran. The image processing technique was used for determination of the contact patch length and contact patch width. Analysis of covariance was used to evaluate the correlations. The highest values of contact length and width and tire deflection occurred at the highest wheel load and lowest tire inflation pressure. Contact patch width is a polynomial (order 2) function of wheel load while there is a linear relationship between tire contact length and wheel load as well as between tire deflection and wheel load. Correlations were developed for the evaluation of contact patch length-rolling resistance, contact patch width-rolling resistance and tire deflection-rolling resistance. It is concluded that the variables studied have a significant effect on rolling resistance. (Author)

  4. Bucket wheel rehabilitation of ERC 1400-30/7 high-capacity excavators from lignite quarries

    Science.gov (United States)

    Vîlceanu, Fl; Iancu, C.

    2016-11-01

    The existence of bucket wheel equipment type ERC 1400-30/7 in lignite quarries with lifetime expired, or in the ultimate life period, together with high cost investments for their replacement, makes rational the efforts made to rehabilitation in order to extend their life. Rehabilitation involves checking operational safety based on relevant expertise of metal structures supporting effective resistance but also the replacement (or modernization) of subassemblies that can increase excavation process productivity, lowering energy consumption, reducing mechanical stresses. This paper proposes an analysis of constructive solution of using a part of the classical bucket wheel, on which are located 9 cutting cups and 9 chargers cups and adding a new part so that the new redesigned bucket-wheel will contain 18 cutting-chargers cups, compared to the classical model. On the CAD model of bucket wheel was performed a static and a dynamic FEA, the results being compared with the yield strength of the material of the entire structure, were checked mechanical stresses in the overall distribution map, and were verified the first 4 vibrating modes the structure compared to real loads. Thus was verified that the redesigned bucket-wheel can accomplish the proposed goals respectively increase excavation process productivity, lowering energy consumption and reducing mechanical stresses.

  5. Aerodynamic analysis of an isolated vehicle wheel

    Science.gov (United States)

    Leśniewicz, P.; Kulak, M.; Karczewski, M.

    2014-08-01

    Increasing fuel prices force the manufacturers to look into all aspects of car aerodynamics including wheels, tyres and rims in order to minimize their drag. By diminishing the aerodynamic drag of vehicle the fuel consumption will decrease, while driving safety and comfort will improve. In order to properly illustrate the impact of a rotating wheel aerodynamics on the car body, precise analysis of an isolated wheel should be performed beforehand. In order to represent wheel rotation in contact with the ground, presented CFD simulations included Moving Wall boundary as well as Multiple Reference Frame should be performed. Sliding mesh approach is favoured but too costly at the moment. Global and local flow quantities obtained during simulations were compared to an experiment in order to assess the validity of the numerical model. Results of investigation illustrates dependency between type of simulation and coefficients (drag and lift). MRF approach proved to be a better solution giving result closer to experiment. Investigation of the model with contact area between the wheel and the ground helps to illustrate the impact of rotating wheel aerodynamics on the car body.

  6. Aerodynamic analysis of an isolated vehicle wheel

    International Nuclear Information System (INIS)

    Leśniewicz, P; Kulak, M; Karczewski, M

    2014-01-01

    Increasing fuel prices force the manufacturers to look into all aspects of car aerodynamics including wheels, tyres and rims in order to minimize their drag. By diminishing the aerodynamic drag of vehicle the fuel consumption will decrease, while driving safety and comfort will improve. In order to properly illustrate the impact of a rotating wheel aerodynamics on the car body, precise analysis of an isolated wheel should be performed beforehand. In order to represent wheel rotation in contact with the ground, presented CFD simulations included Moving Wall boundary as well as Multiple Reference Frame should be performed. Sliding mesh approach is favoured but too costly at the moment. Global and local flow quantities obtained during simulations were compared to an experiment in order to assess the validity of the numerical model. Results of investigation illustrates dependency between type of simulation and coefficients (drag and lift). MRF approach proved to be a better solution giving result closer to experiment. Investigation of the model with contact area between the wheel and the ground helps to illustrate the impact of rotating wheel aerodynamics on the car body.

  7. High frequency vibration characteristics of electric wheel system under in-wheel motor torque ripple

    Science.gov (United States)

    Mao, Yu; Zuo, Shuguang; Wu, Xudong; Duan, Xianglei

    2017-07-01

    With the introduction of in-wheel motor, the electric wheel system encounters new vibration problems brought by motor torque ripple excitation. In order to analyze new vibration characteristics of electric wheel system, torque ripple of in-wheel motor based on motor module and vector control system is primarily analyzed, and frequency/order features of the torque ripple are discussed. Then quarter vehicle-electric wheel system (QV-EWS) dynamics model based on the rigid ring tire assumption is established and the main parameters of the model are identified according to tire free modal test. Modal characteristics of the model are further analyzed. The analysis indicates that torque excitation of in-wheel motor is prone to arouse horizontal vibration, in which in-phase rotational, anti-phase rotational and horizontal translational modes of electric wheel system mainly participate. Based on the model, vibration responses of the QV-EWS under torque ripple are simulated. The results show that unlike vertical low frequency (lower than 20 Hz) vibration excited by road roughness, broadband torque ripple will arouse horizontal high frequency (50-100 Hz) vibration of electric wheel system due to participation of the three aforementioned modes. To verify the theoretical analysis, the bench experiment of electric wheel system is conducted and vibration responses are acquired. The experiment demonstrates the high frequency vibration phenomenon of electric wheel system and the measured order features as well as main resonant frequencies agree with simulation results. Through theoretical modeling, analysis and experiments this paper reveals and explains the high frequency vibration characteristics of electric wheel system, providing references for the dynamic analysis, optimal design of QV-EWS.

  8. Beneath the Wheel - Greenwood Engineering

    DEFF Research Database (Denmark)

    Dias, Kealey; Gravesen, Jens; Hjorth, Poul G.

    This is the report from the 54th European Study Group wiht Industry of the Greenwood Engineering problem. We model pavement response to both a point and distributed loads and compare with data from Greenwood's High Speed Deflectograph Measurements.......This is the report from the 54th European Study Group wiht Industry of the Greenwood Engineering problem. We model pavement response to both a point and distributed loads and compare with data from Greenwood's High Speed Deflectograph Measurements....

  9. Effect of Superfine Grinding on Physicochemical Properties of Apple Pomace

    International Nuclear Information System (INIS)

    Liang, X.; Sun, J.; Ma, H.

    2016-01-01

    The effect of superfine grinding on the physicochemical properties of apple pomace was investigated in this study. The optimal ultrafine powder could be obtained under the conditions of motor speed 450 rpm and fan speed 300 rpm, whose particle size, water-solubility index, angle of repose, total phenolic content and total sugar content were 10.23±0.42 micro m, 33.65±0.91 percent, 39.36±1.59 degree, 12.62±0.34 mg GAE/g and 136.14±3.1 mg/g, respectively. Compared with the traditional powder, the significant increase of water-solubility, total phenolic content and total sugar content could be found while the decrease of angle of repose could be observed. It could be concluded that the bioavailability of functional and nutritional ingredients of apple pomace could be significantly improved by superfine grinding. (author)

  10. Grinding damage assessment on four high-strength ceramics.

    Science.gov (United States)

    Canneto, Jean-Jacques; Cattani-Lorente, Maria; Durual, Stéphane; Wiskott, Anselm H W; Scherrer, Susanne S

    2016-02-01

    The purpose of this study was to assess surface and subsurface damage on 4 CAD-CAM high-strength ceramics after grinding with diamond disks of 75 μm, 54 μm and 18 μm and to estimate strength losses based on damage crack sizes. The materials tested were: 3Y-TZP (Lava), dense Al2O3 (In-Ceram AL), alumina glass-infiltrated (In-Ceram ALUMINA) and alumina-zirconia glass-infiltrated (In-Ceram ZIRCONIA). Rectangular specimens with 2 mirror polished orthogonal sides were bonded pairwise together prior to degrading the top polished surface with diamond disks of either 75 μm, 54 μm or 18 μm. The induced chip damage was evaluated on the bonded interface using SEM for chip depth measurements. Fracture mechanics were used to estimate fracture stresses based on average and maximum chip depths considering these as critical flaws subjected to tension and to calculate possible losses in strength compared to manufacturer's data. 3Y-TZP was hardly affected by grinding chip damage viewed on the bonded interface. Average chip depths were of 12.7±5.2 μm when grinding with 75 μm diamond inducing an estimated loss of 12% in strength compared to manufacturer's reported flexural strength values of 1100 MPa. Dense alumina showed elongated chip cracks and was suffering damage of an average chip depth of 48.2±16.3 μm after 75 μm grinding, representing an estimated loss in strength of 49%. Grinding with 54 μm was creating chips of 32.2±9.1 μm in average, representing a loss in strength of 23%. Alumina glass-infiltrated ceramic was exposed to chipping after 75 μm (mean chip size=62.4±19.3 μm) and 54 μm grinding (mean chip size=42.8±16.6 μm), with respectively 38% and 25% estimated loss in strength. Alumina-zirconia glass-infiltrated ceramic was mainly affected by 75 μm grinding damage with a chip average size of 56.8±15.1 μm, representing an estimated loss in strength of 34%. All four ceramics were not exposed to critical chipping at 18 μm diamond grinding. Reshaping a

  11. Chemical treatment of coal by grinding and aqueous caustic leaching

    Energy Technology Data Exchange (ETDEWEB)

    Balaz, P.; LaCount, R.B.; Kern, D.G.; Turcaniova, L. [Slovak Academy of Sciences, Kosice (Slovakia). Inst. of Geotechnics

    2001-04-01

    The aim of this work has been to point out the possibility of using GACL process for chemical cleaning of brown coal Nivaky (Slovakia) and Pittsburgh coal. Simultaneous grinding and aqueous chemical leaching, which is the principle of the process, reduces the inorganic and inorganic sulfur content in both coals. Dearsenificiation nearly up to 96% is detected in GACL-treated samples of Novaky coal. The possibility of enhancing the recovery of humic acid as a consequence of GACL treatment is demonstrated. The process under study works under atmospheric pressure, temperature of 90{degree}C and NaOH consumption, which is six times lower compared with the MCL process. Further research is needed to minimize the wear of grinding media and to improve the washing step. 24 refs., 7 figs., 3 tabs.

  12. Predicting the wheel rolling resistance regarding important motion parameters using the artificial neural network

    Directory of Open Access Journals (Sweden)

    F Gheshlaghi

    2016-04-01

    Full Text Available Introduction: Rolling resistance is one of the most substantial energy losses when the wheel moves on soft soil. Rolling resistance value optimization will help to improve energy efficiency. Accurate modeling of the interaction soil-tire is an important key to this optimization and has eliminated the need for costly field tests and has reduced the time required to test. Rolling resistance will change because of the tire and wheel motion parameters and characteristics of the ground surface. Some tire design parameters are more important such as the tire diameter, width, tire aspect ratio, lugs form, inflation pressure and mechanical properties of tire structure. On the other hand, the soil or ground surface characteristics include soil type; moisture content and bulk density have an important role in this phenomenon. In addition, the vertical load and the wheel motion parameters such as velocity and tire slip are the other factors which impact on tire rolling resistance. According to same studies about the rolling resistance of the wheel, the wheel is significantly affected by the dynamic load. Tire inflation pressure impacted on rolling resistance of tires that were moving on hard surfaces. Studies showed that the rolling resistance of tires with low inflation pressure (less than 100 kPa was too high. According to Zoz and Griss researches, increasing the tire pressure increases rolling resistance on soft soil but reduces the rolling resistance of on-road tires and tire-hard surface interaction. Based on these reports, the effect of velocity on tire rolling resistance for tractors and vehicles with low velocity (less than 5 meters per second is usually insignificant. According to Self and Summers studies, rolling resistance of the wheel is dramatically affected by dynamic load on the wheel. Artificial Neural Network is one of the best computational methods capable of complex regression estimation which is an advantage of this method compared with

  13. Manufacturing and sustainability of bonding systems for grinding tools

    OpenAIRE

    Linke, B

    2016-01-01

    © 2016, German Academic Society for Production Engineering (WGP). Grinding and honing processes are quality-defining operations in the production of many modern products. Process performance and product quality are contingent on selecting the correct abrasive tool for a specific application. Thus, tools with different bonding systems are used, namely resin bonded tools, vitrified bonded tools, and metallic bonded tools. Tool manufacturers have great knowledge in the choice and intricate prod...

  14. Westinghouse modular grinding process - improvement for follow on processes

    International Nuclear Information System (INIS)

    Fehrmann, Henning

    2013-01-01

    In nuclear power plants (NPP) ion exchange (IX) resins are used in several systems for water treatment. The resins can be in bead or powdered form. For waste treatment of spent IX resins, two methods are basically used: Direct immobilization (e.g. with cement, bitumen, polymer or High Integrity Container (HIC)); Thermal treatment (e.g. drying, oxidation or pyrolysis). Bead resins have some properties (e.g. particle size and density) that can have negative impacts on following waste treatment processes. Negative impacts could be: Floatation of bead resins in cementation process; Sedimentation in pipeline during transportation; Poor compaction properties for Hot Resin Supercompaction (HRSC). Reducing the particle size of the bead resins can have beneficial effects enhancing further treatment processes and overcoming prior mentioned effects. Westinghouse Electric Company has developed a modular grinding process to crush/grind the bead resins. This modular process is designed for flexible use and enables a selective adjustment of particle size to tailor the grinding system to the customer needs. The system can be equipped with a crusher integrated in the process tank and if necessary a colloid mill. The crusher reduces the bead resins particle size and converts the bead resins to a pump able suspension with lower sedimentation properties. With the colloid mill the resins can be ground to a powder. Compared to existing grinding systems this equipment is designed to minimize radiation exposure of the worker during operation and maintenance. Using the crushed and/or ground bead resins has several beneficial effects like facilitating cementation process and recipe development, enhancing oxidation of resins, improving the Hot Resin Supercompaction volume reduction performance. (authors)

  15. Westinghouse modular grinding process - improvement for follow on processes

    Energy Technology Data Exchange (ETDEWEB)

    Fehrmann, Henning [Westinghouse Germany GmbH, Mannheim, State (Germany)

    2013-07-01

    In nuclear power plants (NPP) ion exchange (IX) resins are used in several systems for water treatment. The resins can be in bead or powdered form. For waste treatment of spent IX resins, two methods are basically used: Direct immobilization (e.g. with cement, bitumen, polymer or High Integrity Container (HIC)); Thermal treatment (e.g. drying, oxidation or pyrolysis). Bead resins have some properties (e.g. particle size and density) that can have negative impacts on following waste treatment processes. Negative impacts could be: Floatation of bead resins in cementation process; Sedimentation in pipeline during transportation; Poor compaction properties for Hot Resin Supercompaction (HRSC). Reducing the particle size of the bead resins can have beneficial effects enhancing further treatment processes and overcoming prior mentioned effects. Westinghouse Electric Company has developed a modular grinding process to crush/grind the bead resins. This modular process is designed for flexible use and enables a selective adjustment of particle size to tailor the grinding system to the customer needs. The system can be equipped with a crusher integrated in the process tank and if necessary a colloid mill. The crusher reduces the bead resins particle size and converts the bead resins to a pump able suspension with lower sedimentation properties. With the colloid mill the resins can be ground to a powder. Compared to existing grinding systems this equipment is designed to minimize radiation exposure of the worker during operation and maintenance. Using the crushed and/or ground bead resins has several beneficial effects like facilitating cementation process and recipe development, enhancing oxidation of resins, improving the Hot Resin Supercompaction volume reduction performance. (authors)

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

    Directory of Open Access Journals (Sweden)

    A. Pribulová

    2010-04-01

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

  17. Preparation and characterization of Dendrobium officinale powders through superfine grinding.

    Science.gov (United States)

    Meng, Qingran; Fan, Haoran; Chen, Feng; Xiao, Tiancun; Zhang, Lianfu

    2018-03-01

    Dendrobium officinale has been used in China for several thousand years as a health food and has become one of the most expensive tea materials worldwide as a result of extremely scarce resources in the wild and an increasing demand. Hence, it is very important to improve the depth and width of its application. In the present study, the physico-chemical, surface chemistry and thermal properties of micron range particles and coarse particles prepared by superfine grinding and shear pulverization were investigated. As the particle size decreased, the specific surface area of D. officinale powders increased significantly. Microscopy observations confirmed that superfine grinding effectively changed the original structure of D. officinale. The Fourier transform infrared spectroscopy spectra depicted the characteristic bands shifted in terms of absorbance and/or wave number as the powder particle size decreased. The crystallinity and intensity of the crystal peaks of D. officinale powders increased as the particle size decreased. Moisture sorption isotherms suggested that superfine powders were more unstable as a result of the increase in surface area, as well as the exposure of polar groups. The results of the present study suggest that superfine grinding may provide new methods of processing for D. officinale with respect to further enhancement of its application value. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

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

    Science.gov (United States)

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

    2016-03-01

    Carbon fiber reinforced plastic (CFRP) composites have been intensively used in various industries due to their superior properties. In aircraft and aerospace industry, a large number of holes are required to be drilled into CFRP components at final stage for aircraft assembling. There are two major types of methods for hole making of CFRP composites in industry, twist drilling and its derived multi-points machining methods, and grinding and its related methods. The first type of methods are commonly used in hole making of CFRP composites. However, in recent years, rotary ultrasonic machining (RUM), a hybrid machining process combining ultrasonic machining and grinding, has also been successfully used in drilling of CFRP composites. It has been shown that RUM is superior to twist drilling in many aspects. However, there are no reported investigations on comparisons between RUM and grinding in drilling of CFRP. In this paper, these two drilling methods are compared in five aspects, including cutting force, torque, surface roughness, hole diameter, and material removal rate. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Measurement of drill grinding parameters using laser sensor

    Science.gov (United States)

    Yanping, Peng; Kumehara, Hiroyuki; Wei, Zhang; Nomura, Takashi

    2005-12-01

    To measure the grinding parameters and geometry parameters accurately for a drill point is essential to its design and reconditioning. In recent years, a number of non-contact coordinate measuring apparatuses, using CCD camera or laser sensors, are developed. But, a lot work is to be done for further improvement. This paper reports another kind of laser coordinate meter. As an example of its application, the method for geometry inspection of the drill flank surface is detailed. Measured data from laser scanning on the flank surface around some points with several 2-dimensional curves are analyzed with mathematical procedure. If one of these curves turns to be a straight line, it must be the generatrix of the grinding cone. Thus, the grinding parameters are determined by a set of three generatrices. Then, the measurement method and data processing procedure are proposed. Its validity is assessed by measuring a sample with given parameters. The point geometry measured agrees well with the known values. In comparison with other methods in the published literature, it is simpler in computation and more accurate in results.

  20. Mechanical design and qualification of IR filter mounts and filter wheel of INSAT-3D sounder for low temperature

    Science.gov (United States)

    Vora, A. P.; Rami, J. B.; Hait, A. K.; Dewan, C. P.; Subrahmanyam, D.; Kirankumar, A. S.

    2017-11-01

    Next generation Indian Meteorological Satellite will carry Sounder instrument having subsystem of filter wheel measuring Ø260mm and carrying 18 filters arranged in three concentric rings. These filters made from Germanium, are used to separate spectral channels in IR band. Filter wheel is required to be cooled to 214K and rotated at 600 rpm. This Paper discusses the challenges faced in mechanical design of the filter wheel, mainly filter mount design to protect brittle germanium filters from failure under stresses due to very low temperature, compactness of the wheel and casings for improved thermal efficiency, survival under vibration loads and material selection to keep it lighter in weight. Properties of Titanium, Kovar, Invar and Aluminium materials are considered for design. The mount has been designed to accommodate both thermal and dynamic loadings without introducing significant aberrations into the optics or incurring permanent alignment shifts. Detailed finite element analysis of mounts was carried out for stress verification. Results of the qualification tests are discussed for given temperature range of 100K and vibration loads of 12g in Sine and 11.8grms in Random at mount level. Results of the filter wheel qualification as mounted in Electro Optics Module (EOM) are also presented.

  1. Project considerations and design of systems for wheeling cogenerated power

    Energy Technology Data Exchange (ETDEWEB)

    Tessmer, R.G. Jr.; Boyle, J.R.; Fish, J.H. III; Martin, W.A.

    1994-08-01

    Wheeling electric power, the transmission of electricity not owned by an electric utility over its transmission lines, is a term not generally recognized outside the electric utility industry. Investigation of the term`s origin is intriguing. For centuries, wheel has been used to describe an entire machine, not just individual wheels within a machine. Thus we have waterwheel, spinning wheel, potter`s wheel and, for an automobile, wheels. Wheel as a verb connotes transmission or modification of forces and motion in machinery. With the advent of an understanding of electricity, use of the word wheel was extended to be transmission of electric power as well as mechanical power. Today, use of the term wheeling electric power is restricted to utility transmission of power that it doesn`t own. Cogeneration refers to simultaneous production of electric and thermal power from an energy source. This is more efficient than separate production of electricity and thermal power and, in many instances, less expensive.

  2. Y-TZP zirconia regeneration firing: Microstructural and crystallographic changes after grinding.

    Science.gov (United States)

    Ryan, Daniel Patrick Obelenis; Fais, Laiza Maria Grassi; Antonio, Selma Gutierrez; Hatanaka, Gabriel Rodrigues; Candido, Lucas Miguel; Pinelli, Ligia Antunes Pereira

    2017-07-26

    This study evaluated microstructural and crystallographic phase changes after grinding (G) and regeneration firing/anneling (R) of Y-TZP ceramics. Thirty five bars (Lava TM and Ice Zirkon) were divided: Y-TZP pre-sintered, control (C), regeneration firing (R), dry grinding (DG), dry grinding+regeneration firing (DGR), wet grinding (WG) and wet grinding+regeneration firing (WGR). Grinding was conducted using a diamond bur and annealing at 1,000°C. The microstructure was analyzed by SEM and the crystalline phases by X-ray diffraction (XRD). XRD showed that pre-sintered specimens contained tetragonal and monoclinic phases, while groups C and R showed tetragonal, cubic and monoclinic phases. After grinding, the cubic phase was eliminated in all groups. Annealing (DGR and WGR) resulted in only tetragonal phase. SEM showed semi-circular cracks after grinding and homogenization of particles after annealing. After grinding, surfaces show tetragonal and monoclinic phases and R can be assumed to be necessary prior to porcelain layering when grinding is performed.

  3. Grinding model and material removal mechanism of medical nanometer zirconia ceramics.

    Science.gov (United States)

    Zhang, Dongkun; Li, Changhe; Jia, Dongzhou; Wang, Sheng; Li, Runze; Qi, Xiaoxiao

    2014-01-01

    Many patents have been devoted to developing medical nanometer zirconia ceramic grinding techniques that can significantly improve both workpiece surface integrity and grinding quality. Among these patents is a process for preparing ceramic dental implants with a surface for improving osseo-integration by sand abrasive finishing under a jet pressure of 1.5 bar to 8.0 bar and with a grain size of 30 µm to 250 µm. Compared with other materials, nano-zirconia ceramics exhibit unmatched biomedical performance and excellent mechanical properties as medical bone tissue and dentures. The removal mechanism of nano-zirconia materials includes brittle fracture and plastic removal. Brittle fracture involves crack formation, extension, peeling, and chipping to completely remove debris. Plastic removal is similar to chip formation in metal grinding, including rubbing, ploughing, and the formation of grinding debris. The materials are removed in shearing and chipping. During brittle fracture, the grinding-led transverse and radial extension of cracks further generate local peeling of blocks of the material. In material peeling and removal, the mechanical strength and surface quality of the workpiece are also greatly reduced because of crack extension. When grinding occurs in the plastic region, plastic removal is performed, and surface grinding does not generate grinding fissures and surface fracture, producing clinically satisfactory grinding quality. With certain grinding conditions, medical nanometer zirconia ceramics can be removed through plastic flow in ductile regime. In this study, we analyzed the critical conditions for the transfer of brittle and plastic removal in nano-zirconia ceramic grinding as well as the high-quality surface grinding of medical nanometer zirconia ceramics by ELID grinding.

  4. Design of Wheeled Mobile Robot with Tri-Star Wheel as Rescue Robot

    Directory of Open Access Journals (Sweden)

    Rafiuddin Syam

    2016-05-01

    Full Text Available This study aims to design, and analyze a mobilerobot that can handle some of the obstacles, they are unevensurfaces, slopes, can also climb stairs. WMR in this study is Tristarwheel that is containing three wheels for each set. Onaverage surface only two wheels in contact with the surface, ifthere is an uneven surface or obstacle then the third wheel willrotate with the rotation center of the wheel in contact with theleading obstacle then only one wheel in contact with the surface.This study uses the C language program. Furthermore, theminimum thrust to be generated torque of the motor andtransmission is 9.56 kg. The results obtained by calculation andanalysis of DC motors used must have a torque greater than14.67 kg.cm. Minimum thrust to be generated motor torque andthe transmission is 9.56 kg. The experimental results give goodresults for robot to moving forward, backward, turn left, turnright and climbing the stairs

  5. Umbrella Wheel - a stair-climbing and obstacle-handling wheel design concept

    DEFF Research Database (Denmark)

    Iversen, Simon; Jouffroy, Jerome

    2017-01-01

    This paper proposes a new design for stair-climbing using a wheel that can split into segments and walk up stairs or surmount other obstacles often found where humans traverse, while still being able to retain a perfectly round shape for traveling on smooth ground. Using this change of configurat......This paper proposes a new design for stair-climbing using a wheel that can split into segments and walk up stairs or surmount other obstacles often found where humans traverse, while still being able to retain a perfectly round shape for traveling on smooth ground. Using this change...... of configuration, staircases with a wide range of dimensions can be covered efficiently and safely. The design, named Umbrella Wheel, can consist of as many wheel segments as desired, and as few as two. A smaller or higher number of wheel segments has advantages and disadvantages depending on the specific...

  6. Wheeling rates evaluation using optimal power flows

    International Nuclear Information System (INIS)

    Muchayi, M.; El-Hawary, M. E.

    1998-01-01

    Wheeling is the transmission of electrical power and reactive power from a seller to a buyer through a transmission network owned by a third party. The wheeling rates are then the prices charged by the third party for the use of its network. This paper proposes and evaluates a strategy for pricing wheeling power using a pricing algorithm that in addition to the fuel cost for generation incorporates the optimal allocation of the transmission system operating cost, based on time-of-use pricing. The algorithm is implemented for the IEEE standard 14 and 30 bus system which involves solving a modified optimal power flow problem iteratively. The base of the proposed algorithm is the hourly spot price. The analysis spans a total time period of 24 hours. Unlike other algorithms that use DC models, the proposed model captures wheeling rates of both real and reactive power. Based on the evaluation, it was concluded that the model has the potential for wide application in calculating wheeling rates in a deregulated competitive power transmission environment. 9 refs., 3 tabs

  7. Non-Harmonic Fourier Analysis for bladed wheels damage detection

    Science.gov (United States)

    Neri, P.; Peeters, B.

    2015-11-01

    The interaction between bladed wheels and the fluid distributed by the stator vanes results in cyclic loading of the rotating components. Compressors and turbines wheels are subject to vibration and fatigue issues, especially when resonance conditions are excited. Even if resonance conditions can be often predicted and avoided, high cycle fatigue failures can occur, causing safety issues and economic loss. Rigorous maintenance programs are then needed, forcing the system to expensive shut-down. Blade crack detection methods are beneficial for condition-based maintenance. While contact measurement systems are not always usable in exercise conditions (e.g. high temperature), non-contact methods can be more suitable. One (or more) stator-fixed sensor can measure all the blades as they pass by, in order to detect the damaged ones. The main drawback in this situation is the short acquisition time available for each blade, which is shortened by the high rotational speed of the components. A traditional Discrete Fourier Transform (DFT) analysis would result in a poor frequency resolution. A Non-Harmonic Fourier Analysis (NHFA) can be executed with an arbitrary frequency resolution instead, allowing to obtain frequency information even with short-time data samples. This paper shows an analytical investigation of the NHFA method. A data processing algorithm is then proposed to obtain frequency shift information from short time samples. The performances of this algorithm are then studied by experimental and numerical tests.

  8. Deformation processes within wheel-rail adhesion in contact area

    Science.gov (United States)

    Albagachiev, A. Yu; Keropyan, A. M.

    2018-03-01

    The study of working surface deformation during interaction of open-pit locomotive tires allowed defining outstanding features of phenomena occurring in the contact area of interacting surfaces. It was found that processes typical for plastic saturated contact occur in the area of wheel-rail interaction of industrial railway transport. In case of plastic deformation exposed to heavy loads typical for open-pit locomotives, upon all rough surfaces of the contour contact area being fully deformed, the frame on which they are found is exposed to plastic deformation. Plastic deformation of roughness within the contact area of interacting surfaces leads to the increase in the actual area of their contact and, therefore, increases the towing capacity of mining machines. Finally, the available data on deformation characteristics with regard to processes occurring in the contact area of wheel-rail interaction will allow making theoretical forecasts on the expected design value of friction coefficient and, therefore, the towing capacity of open-pit locomotives.

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

    Directory of Open Access Journals (Sweden)

    Basirun Nurul Fasihah

    2017-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-05-01

    Isoflavones impart health benefits and their overall content and profile in foods are greatly influenced at each step during processing. In this study, 2 soybean varieties (Prosoy and black soybean) were processed with 3 different grinding (ambient, cold, and hot grinding) and heating methods (traditional stove cooking, 1-phase UHT, and 2-phase UHT) for soymilk making. The results showed after cold, ambient, and hot grinding, the total isoflavones were 3917, 5013, and 5949 nmol/g for Prosoy; the total isoflavones were 4073, 3966, and 4284 nmol/g for black soybean. Grinding could significantly increase isoflavone extraction. The grinding process had a destructive effect on isoflavones and this effect varied with grinding temperature. Different heating methods had different effects on different isoflavone forms. Two soybean varieties showed distinct patterns with respect to the change of isoflavone profile during processing. © 2015 Institute of Food Technologists®

  12. Analysis of reverse heat transfer for conventional and optimized lubri-cooling methods during tangential surface grinding of ABNT 1020 steel

    Directory of Open Access Journals (Sweden)

    Henrique Cotait Razuk

    Full Text Available Abstract A numerical thermal model was developed to evaluate the heat flux which is conducted to a rectangular workpiece of steel plate ABNT 1020, thus making it possible to compute the maximum temperature in the grinding surface, taking into account the rectangular distribution of heat flux, the thermal properties of the grinding wheel conventional Al2O3, the piece to be machined and the lubri-refrigerating fluid. The finite volume method was employed for the discretization of the direct thermal problem from the heat diffusion equation associated with the two-dimensional problem of heat conduction in transient regime. The inverse thermal problem was solved by the Golden Section technique. The thermal flux, when compared to the conventional technique of method of application fluid, was reduced by 84.0% in the practices performed with cutting depth of 30µm, at 74.0% in practices with cutting depth of 45µm and 61.2% in the aggressive practices of 60µm, thus demonstrating the applicability of the optimized method for fluid application.

  13. Ontology-based coupled optimisation design method using state-space analysis for the spindle box system of large ultra-precision optical grinding machine

    Science.gov (United States)

    Wang, Qianren; Chen, Xing; Yin, Yuehong; Lu, Jian

    2017-08-01

    With the increasing complexity of mechatronic products, traditional empirical or step-by-step design methods are facing great challenges with various factors and different stages having become inevitably coupled during the design process. Management of massive information or big data, as well as the efficient operation of information flow, is deeply involved in the process of coupled design. Designers have to address increased sophisticated situations when coupled optimisation is also engaged. Aiming at overcoming these difficulties involved in conducting the design of the spindle box system of ultra-precision optical grinding machine, this paper proposed a coupled optimisation design method based on state-space analysis, with the design knowledge represented by ontologies and their semantic networks. An electromechanical coupled model integrating mechanical structure, control system and driving system of the motor is established, mainly concerning the stiffness matrix of hydrostatic bearings, ball screw nut and rolling guide sliders. The effectiveness and precision of the method are validated by the simulation results of the natural frequency and deformation of the spindle box when applying an impact force to the grinding wheel.

  14. Railway bogie vibration analysis by mathematical simulation model and a scaled four-wheel railway bogie set

    Science.gov (United States)

    Visayataksin, Noppharat; Sooklamai, Manon

    2018-01-01

    The bogie is the part that connects and transfers all the load from the vehicle body onto the railway track; interestingly the interaction between wheels and rails is the critical point for derailment of the rail vehicles. However, observing or experimenting with real bogies on rail vehicles is impossible due to the operational rules and safety concerns. Therefore, this research aimed to develop a vibration analysis set for a four-wheel railway bogie by constructing a four-wheel bogie with scale of 1:4.5. The bogie structures, including wheels and axles, were made from an aluminium alloy, equipped with springs and dampers. The bogie was driven by an electric motor using 4 round wheels instead of 2 straight rails, with linear velocity between 0 to 11.22 m/s. The data collected from the vibration analysis set was compared to the mathematical simulation model to investigate the vibration behavior of the bogie, especially the hunting motion. The results showed that vibration behavior from a scaled four-wheel railway bogie set significantly agreed with the mathematical simulation model in terms of displacement and hunting frequency. The critical speed of the wheelset was found by executing the mathematical simulation model at 13 m/s.

  15. Study on control schemes of flexible steering system of a multi-axle all-wheel-steering robot

    Directory of Open Access Journals (Sweden)

    Pingxia Zhang

    2016-05-01

    Full Text Available It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.

  16. Comparison of different grinding procedures on the flexural strength of zirconia.

    Science.gov (United States)

    Işeri, Ufuk; Ozkurt, Zeynep; Yalnız, Ayşe; Kazazoğlu, Ender

    2012-05-01

    The surface of zirconia ceramic is damaged during grinding, which may affect the mechanical properties of the material. The purpose of this study was to compare the biaxial flexural strength of zirconia after different grinding procedures and to measure the temperature rise from grinding. Forty disk-shaped zirconia specimens (15 × 1.2 mm) with a smaller disk in the center of each disk (1 × 3 mm) were divided into 4 groups (n=10). The specimens were ground with a high-speed handpiece and micromotor with 2 different grinding protocols, continual grinding and periodic grinding (10 seconds grinding with 10 seconds duration), until the smaller disk was removed. Control specimens without the center disk (n=10) were analyzed without grinding. The biaxial flexural strengths of the disks were determined in a universal testing machine at a crosshead speed of 0.5 mm/min. The fracture strength (MPa) was recorded, and the results were analyzed using a 1-way ANOVA, Tukey HSD test, Student's t test, and Pearson correlation test (α=05). All grinding procedures significantly decreased flexural strength (Pmicromotor groups (718 MPa). The temperature values obtained from micromotor grinding (127°C) were significantly higher than those from high-speed handpiece grinding (63°C) (P<.01). Grinding zirconia decreased flexural strength. Zirconia material ground with a high-speed handpiece run continually caused the least reduction in flexural strength. Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  17. Grinding Si3N4 Powder In Si3N4 Equipment

    Science.gov (United States)

    Herbell, Thomas P.; Freedman, Marc R.; Kiser, James D.

    1989-01-01

    Three methods of grinding compared. Report based on study of grinding silicon nitride powder in preparation for sintering into solid ceramic material. Attrition, vibratory, and ball mills lined with reaction-bonded silicon nitride tested. Rates of reduction of particle sizes and changes in chemical compositions of powders measured so grinding efficiences and increases in impurity contents from wear of mills and media evaluated for each technique.

  18. MODELING AND OPTIMIZATION OF CYLINDRICAL GRINDING PARAMETERS FOR MRR AND SURFACE ROUGHNESS

    OpenAIRE

    Kshitij R Patil1, Rupesh J Karande2, Dadaso D. Mohite3, Vishwas S Jadhav4

    2017-01-01

    Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operations. The grinding process plays an important role in every manufacturing activity. The surface properties can be altered by changing various grinding parameters in order to achieve best surface finish resulting in low surface roughness value and with possible maximum metal removal rate. Four parameters, namely spindle speed, feed rate, depth of cut and hardness of material were identi...

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

    OpenAIRE

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

    2011-01-01

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

  20. Interproximal grinding (disking) of caries in primary molars, attitudes and the extent utilized in a Swedish County.

    Science.gov (United States)

    Granath, Johanna; Asztély, Anna; Lundgren, Ted

    2018-04-30

    To assess the occurrence of interproximal grinding as a caries therapy in primary molars, to what degree grinding replaced conventional restorative caries therapy, to what extent anaesthesia was used while grinding and to assess open comments about attitudes about grinding. A questionnaire was sent to 108 public dental service clinics with questions concerning the use of grinding as a therapy and alternative to restorative treatment, the use of anaesthesia prior to conventional caries therapy and grinding, respectively. In addition, a content analysis of open comments about grinding was performed. Grinding had been performed in 96% of the clinics. Two-thirds of the dentists used grinding as an alternative to conventional restorative treatment at some point. Most dentists used anaesthesia prior to restorative therapy. Prior to grinding, the frequency of anaesthesia was lower (median 5.0) than for conventional restorative therapy (median 8.7) (p grinding. Grinding has been widely practiced in parts of Sweden, is presently a technique employed by a multitude of dentists, and that anaesthesia is used less frequently prior to grinding, in comparison to conventional restorative therapy. Dentist considered grinding as a treatment option in specific situations.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    An effective, robust, and inexpensive grinding device for the grinding of herb samples like bark and roots was developed by rebuilding a commercially available coffee grinder. The grinder was constructed to be able to provide various particle sizes, to be easy to clean, and to have a minimum...... of dead volume. The recovery of the sample when grinding as little as 50 mg of crude Cinchona bark was about 60%. Grinding is performed in seconds with no rise in temperature, and the grinder is easily disassembled to be cleaned. The influence of the particle size of the obtained powders on the recovery...

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

    International Nuclear Information System (INIS)

    Shastry, S.S.; Kher, R.K.

    1979-01-01

    Grinding of polycrystalline CaSO 4 :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.)

  3. Lab-scale roller table mill for investigating the grinding behaviour of coal

    Energy Technology Data Exchange (ETDEWEB)

    Werner, V.; Zelkowski, J.; Schoenert, K. [Inst. for Energy Process Engineering and Fuel Technology and Inst. of Mineral Processing, Univ. Clausthal, Clausthal-Zellerfeld (Germany)

    1999-11-01

    The test mill is equipped with one roller. The material bed can be discharged completely after overroling. Grinding force, torque and gap width are measured. Cycle tests with three coals have been performed for simulating a closed circuit process. The grinding behaviour is characterized by the following relations: compaction of the particle bed and specific power draft vs. specific grinding force, production of fine material (dust), circuit factor, specific surface of the dust and specific work-input of the grinding circuit vs. specific power draft. (orig.)

  4. An Efficient, Robust, and Inexpensive Grinding Device for Herbal Samples like Cinchona Bark.

    Science.gov (United States)

    Hansen, Steen Honoré; Holmfred, Else; Cornett, Claus; Maldonado, Carla; Rønsted, Nina

    2015-01-01

    An effective, robust, and inexpensive grinding device for the grinding of herb samples like bark and roots was developed by rebuilding a commercially available coffee grinder. The grinder was constructed to be able to provide various particle sizes, to be easy to clean, and to have a minimum of dead volume. The recovery of the sample when grinding as little as 50 mg of crude Cinchona bark was about 60%. Grinding is performed in seconds with no rise in temperature, and the grinder is easily disassembled to be cleaned. The influence of the particle size of the obtained powders on the recovery of analytes in extracts of Cinchona bark was investigated using HPLC.

  5. Experimental and Numerical Investigations in Shallow Cut Grinding by Workpiece Integrated Infrared Thermopile Array.

    Science.gov (United States)

    Reimers, Marcel; Lang, Walter; Dumstorff, Gerrit

    2017-09-30

    The purpose of our study is to investigate the heat distribution and the occurring temperatures during grinding. Therefore, we did both experimental and numerical investigations. In the first part, we present the integration of an infrared thermopile array in a steel workpiece. Experiments are done by acquiring data from the thermopile array during grinding of a groove in a workpiece made of steel. In the second part, we present numerical investigations in the grinding process to further understand the thermal characteristic during grinding. Finally, we conclude our work. Increasing the feed speed leads to two things: higher heat flux densities in the workpiece and higher temperature gradients in the material.

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

    Science.gov (United States)

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

    2014-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Martin Novák

    2015-05-01

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

  8. Experimental and Numerical Investigations in Shallow Cut Grinding by Workpiece Integrated Infrared Thermopile Array

    Directory of Open Access Journals (Sweden)

    Marcel Reimers

    2017-09-01

    Full Text Available The purpose of our study is to investigate the heat distribution and the occurring temperatures during grinding. Therefore, we did both experimental and numerical investigations. In the first part, we present the integration of an infrared thermopile array in a steel workpiece. Experiments are done by acquiring data from the thermopile array during grinding of a groove in a workpiece made of steel. In the second part, we present numerical investigations in the grinding process to further understand the thermal characteristic during grinding. Finally, we conclude our work. Increasing the feed speed leads to two things: higher heat flux densities in the workpiece and higher temperature gradients in the material.

  9. Improving the plunge grinding technology efficiency through a rigid scheme use

    Directory of Open Access Journals (Sweden)

    І. О. Рябенков

    2016-07-01

    Full Text Available Theoretical bases of grinding technology researches results form the basis of this work. It has been shown that grinding efficiency increase can be achieved through the use of new kinematic grinding schemes and progressive designs of abrasive tools. However, not enough attention is paid to the calculation of the main technological machining parameters with due regard to separate processes of cutting and friction at grinding, thus restricting the effective application of these kinematic grinding schemes and scientifically grounded selection of optimal processing conditions. In this paper a mathematical model has been developed for determining the material removal rate and cutting force at plunge grinding, what made it possible to substantiate reducing the power strength at grinding and to increase productivity. Calculations revealed that the cutting force at plunge grinding is conditioned by the disk bond friction against the material being processed, the intensity of which in the course of processing time increases proportionally due to an increase of elastic movements in the technological system. Proceeding from these results the optimum grinding conditions based on the use of the abrasive disk that works under self-sharpening conditions, thus eliminating the disk bond friction against the material being processed, have been grounded. In this case, the abrasive disk provides complete removal of the processed material supplied to the cutting zone at the nominal speed of a workpiece movement. Also the ability to reduce cutting forces through the increase of the disk speed and the workpiece speed ratio has been shown

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

    International Nuclear Information System (INIS)

    Neauport, J.; Cormont, P.; Destribats, J.; Legros, P.; Ambard, C.

    2009-01-01

    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)

  11. Evaluation of the 30 Ton CHA Crane Wheel Axle Modification

    International Nuclear Information System (INIS)

    RICH, J.W.

    2002-01-01

    An existing design for eccentric bushings was utilized and updated as necessary to accommodate minor adjustment as required to correct wheel alignment on the North West Idler wheel. The design is revised to install eccentric bushings on only one end

  12. Tensegrital Wheel for Enhanced Surface Mobility, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ProtoInnovations introduces the "tensegrital wheel" an inventive concept for wheeled locomotion that exploits the geometric and mechanical attributes of a tensegrity...

  13. Maximum Torque and Momentum Envelopes for Reaction Wheel Arrays

    Science.gov (United States)

    Markley, F. Landis; Reynolds, Reid G.; Liu, Frank X.; Lebsock, Kenneth L.

    2009-01-01

    Spacecraft reaction wheel maneuvers are limited by the maximum torque and/or angular momentum that the wheels can provide. For an n-wheel configuration, the torque or momentum envelope can be obtained by projecting the n-dimensional hypercube, representing the domain boundary of individual wheel torques or momenta, into three dimensional space via the 3xn matrix of wheel axes. In this paper, the properties of the projected hypercube are discussed, and algorithms are proposed for determining this maximal torque or momentum envelope for general wheel configurations. Practical strategies for distributing a prescribed torque or momentum among the n wheels are presented, with special emphasis on configurations of four, five, and six wheels.

  14. Reaction Wheel Disturbance Model Extraction Software, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Reaction wheel disturbances are some of the largest sources of noise on sensitive telescopes. Such wheel-induced mechanical noises are not well characterized....

  15. Grinding and polishing of conformal windows and domes

    Science.gov (United States)

    Fess, Edward; Ross, James; Matthews, Greg

    2017-05-01

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

  16. Dissolution enhancement of atorvastatin calcium by co-grinding technique.

    Science.gov (United States)

    Prabhu, Priyanka; Patravale, Vandana

    2016-08-01

    Atorvastatin calcium (AC) is a BCS class II drug which shows poor bioavailability due to inadequate dissolution. Solid dispersions present a promising option to enhance the solubility of poorly soluble drugs. Co-grinding with hydrophilic excipients is an easy and economical technique to improve the solubility of poorly soluble drugs and is free from usage of organic solvents. The aim of the present study was to explore novel carrier VBP-1 (organosulphur compound) for formulating a solid dispersion by using a simple, commercially viable co-grinding technique to enhance the dissolution of AC and to develop an oral formulation of the same. Composition of the solid dispersion was optimized based on the release profile in pH 1.2 buffer. The optimized solid dispersion was further characterized for flow properties, DSC, FTIR spectroscopy, XRD, contact angle, SEM studies and release profile in phosphate buffer pH 6.8. The developed solid dispersion gave similar release profile as the innovator formulation (Lipitor® tablets) in both pH 1.2 buffer and phosphate buffer pH 6.8. The developed solid dispersion was formulated into hard gelatin capsules (size 3). The developed capsules were found to give similar release as the innovator formulation in both pH 1.2 buffer and phosphate buffer pH 6.8. The developed capsules were found to be stable for a period of 6 months. Anti-hyperlipidemic efficacy studies in rats showed higher reduction in cholesterol and triglyceride levels by the developed capsules in comparison to pure AC. In conclusion, novel carrier VBP-1 was successfully employed to enhance the dissolution of AC using co-grinding technique.

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

    International Nuclear Information System (INIS)

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

    1996-08-01

    This paper describes work done at Los Alamos National Laboratory (LANL) in collaboration with the Department of Energy Rocky Flats Field Office (DOE/RFFO) and with the National Institute of Standards and Technology (NIST), Boulder, Colorado. Researchers on this project have developed a method for cryogenic grinding of mixed wastes to homogenize and, thereby, to acquire a representative sample of the materials. There are approximately 220,000 waste drums owned by the Rocky Flats Environmental Technology Site (RFETS)-50,000 at RFETS and 170,000 at the Idaho National Engineering Laboratory. The cost of sampling the heterogeneous distribution of waste in each drum is prohibitive. In an attempt to produce a homogeneous mixture of waste that would reduce greatly the cost of sampling, researchers at NIST and RFETS are developing a cryogenic grinder. The Los Alamos work herein described addresses the implementation issues of the task. The first issue was to ascertain whether samples of the open-quotes small 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

  18. Grinding temperature and energy ratio coefficient in MQL grinding of high-temperature nickel-base alloy by using different vegetable oils as base oil

    OpenAIRE

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

    2016-01-01

    Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM–III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type t...

  19. Corrosion of Cast Iron Mill Plates in Wet Grinding

    Directory of Open Access Journals (Sweden)

    Anthony ANDREWS

    2010-12-01

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

  20. 29 CFR 1910.215 - Abrasive wheel machinery.

    Science.gov (United States)

    2010-07-01

    ... be securely fastened to the spindle and the bearing surface shall run true. When more than one wheel... 29 Labor 5 2010-07-01 2010-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a...

  1. 49 CFR 229.75 - Wheels and tire defects.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Wheels and tire defects. 229.75 Section 229.75....75 Wheels and tire defects. Wheels and tires may not have any of the following conditions: (a) A... two adjoining spots that are each two or more inches in length. (e) A seam running lengthwise that is...

  2. Risk assessment of soil compaction in Europe – Rubber tracks or wheels on machinery

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Greve, Mogens Humlekrog; Schjønning, Per

    2018-01-01

    Subsoil compaction is persistent and affects the wide diversity of ecological services provided by agricultural soils. Efficient risk assessment tools are required to identify sustainable agricultural practices. Vehicles should not transmit stresses that exceed soil strength. Wheel load is the pr......Subsoil compaction is persistent and affects the wide diversity of ecological services provided by agricultural soils. Efficient risk assessment tools are required to identify sustainable agricultural practices. Vehicles should not transmit stresses that exceed soil strength. Wheel load...... the magnitude of contact stresses, (ii) compare effects of traffic on soil physical properties using tires or tracks, and (iii) evaluate a state-of-the-art method for risk assessment of soil compaction beneath tracks or tires at the European level. We measured contact stress below a fully-loaded sugar beet....... The contact area was larger and the maximum and vertical stress smaller beneath the rubber track than beneath the tire. Nevertheless, stress distribution beneath the rubber track was far from uniform, presenting high peak stresses beneath the wheels and rollers. Dry bulk density was similar after traffic...

  3. Mathematical model of rolling an elastic wheel over deformable support base

    Science.gov (United States)

    Volskaia, V. N.; Zhileykin, M. M.; Zakharov, A. Y.

    2018-02-01

    One of the main direction of economic growth in Russia remains to be a speedy development of north and northeast regions that are the constituents of the 60 percent of the country territory. The further development of these territories requires new methods and technologies for solving transport and technological problems when off-road transportation of cargoes and people is conducting. One of the fundamental methods of patency prediction is imitation modeling of wheeled vehicles movement in different operating conditions. Both deformable properties of tires and physical and mechanical properties of the ground: normal tire deflection and gauge depth; variation of contact patch area depending on the load and pressure of air in the tire; existence of hysteresis losses in the tire material which are influencing on the rolling resistance due to friction processes between tire and ground in the contact patch; existence of the tangential reaction from the ground by entire contact area influence on the tractive patency. Nowadays there are two main trends in theoretical research of interaction wheeled propulsion device with ground: analytical method involving mathematical description of explored process and finite element method based on computational modeling. Mathematical models of interaction tire with the ground are used both in processes of interaction individual wheeled propulsion device with ground and researches of mobile vehicle dynamical models operated in specific road and climate conditions. One of the most significant imperfection of these models is the description of interaction wheel with flat deformable support base whereas profile of real support base surface has essential height of unevenness which is commensurate with radius of the wheel. The description of processes taking place in the ground under influence of the wheeled propulsion device using the finite element method is relatively new but most applicable lately. The application of this method allows

  4. THE PROCESS OF FORMATION OF RAILWAY WHEEL DAMAGES AND TIRES IN OPERATION

    Directory of Open Access Journals (Sweden)

    N. A. Grischenko

    2015-01-01

    Full Text Available Purpose. The dependence analysis of structural changes in the metal of railway wheels and tires from indicated influences in operation, for the further development of strategy of service reliability growth. Methodology. Test materials are the details selected from railway wheels which were taken out of operation beforehand because of various damages. Micro-structural researches were made with the use of light microscope Epiquant and electron microscope. The sizing of structural elements was done by using the methods of quantitative metallography. Findings. Over the past few decades the rapid development of industry was supported by the steady growth of intensity of using railway transport. In this case simultaneous increase of load at wheel set axle, with the increase of speed was accompanied by natural increase of the amount of cases of premature wheels and tires’ withdrawing out of operation. Railway wheel, except the formation of metal layer at rolling surface with the high defects concentration of crystal structure and first of all dislocations, falls under thermal influence from interaction with break blocks. The nature of joint influence (cold deformation and heating on the metal rim of a wheel is conditioned by the appearance of sufficiently high gradients of structural changes that can be considered as the influence on the level of internal residual stresses. In case of the rise of volume part of carbide phase at a constant ferrite grain size, it is achieved only by the increasing of dislocation nucleation sources without changing the number of annihilation positions. In this case the accumulation of dislocations at the initial stages of plastic deformation (in metal volume in front of delta arm crack will lead to the formation of cementite globes around certain interlocked dislocation density. In contrast the sharp increase of deformation hardening carbon steel parameters is observed. Originality. During the braking of locomotive the

  5. Vegetation response to wagon wheel camp layouts.

    African Journals Online (AJOL)

    Wagon wheel camp layouts have been favoured, in some quarters, for rotational grazing due to the economy and convenience of having the camps radially arranged around central facilities. A possible disadvantage of such layouts is the tendency for over-grazing near the hub and under-grazing at the extremities.

  6. Examination of a failed fifth wheel coupling

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1998-03-01

    Full Text Available Examination of a fifth wheel coupling which had failed in service showed that it had been modified and that the operating handle had been moved from its original design position. This modification completely eliminated the safety device designed...

  7. Omnidirectional Wheel-Legged Hybrid Mobile Robot

    Directory of Open Access Journals (Sweden)

    István Vilikó

    2015-06-01

    Full Text Available The purpose of developing hybrid locomotion systems is to merge the advantages and to eliminate the disadvantages of different type of locomotion. The proposed solution combines wheeled and legged locomotion methods. This paper presents the mechatronic design approach and the development stages of the prototype.

  8. Investigating Functions with a Ferris Wheel

    Science.gov (United States)

    Johnson, Heather Lynn; Hornbein, Peter; Azeem, Sumbal

    2016-01-01

    The authors provide a dynamic Ferris wheel computer activity that teachers can use as an instructional tool to help students investigate functions. They use a student's work to illustrate how students can use relationships between quantities to further their thinking about functions.

  9. The physics of wheel-rail stability

    Science.gov (United States)

    Tan, B. T. G.

    2018-05-01

    This article discusses, at a simple level, the dynamics of the wheel-rail interface, which is fundamental to the stability of rail vehicles. The physics underlying this topic deserves to be better known by physicists and physics students, as it underpins such an important part of our technological infrastructure.

  10. 49 CFR 215.103 - Defective wheel.

    Science.gov (United States)

    2010-10-01

    ... of the rim; or, (i) A wheel on the car has been welded unless the car is being moved for repair in... on the car shows evidence of being loose such as oil seepage on the back hub or back plate; (h) A...

  11. Steady state modeling of desiccant wheels

    DEFF Research Database (Denmark)

    Bellemo, Lorenzo; Elmegaard, Brian; Kærn, Martin Ryhl

    2014-01-01

    Desiccant wheels are rotary desiccant dehumidifiers used in air conditioning and drying applications. The modeling of simultaneous heat and mass transfer in these components is crucial for estimating their performances, as well as for simulating and optimizing their implementation in complete...

  12. The time has come for retail wheeling

    International Nuclear Information System (INIS)

    Dahlen, D.O.; Achinger, S.K.

    1993-01-01

    Retail wheeling, the transmission and distribution of electric power for end users, fosters competition and promotes the efficient use of resources. Access to electric-utility transmission and distribution systems would establish competitive electric markets by permitting retail customers to obtain the lowest cost for energy which would meet their specific needs. Among electric utilities and their customers, the idea of allowing market forces to attract supply and set prices is a current controversy. To counter the anticompetitive effects of recent mergers in the wholesale market, the Federal Energy Regulatory Commission (FERC) has mandated open transmission access for wholesale customers. However, the FERC denied access to retail customers and qualifying facilities (QF) in both its Northeast Utilities (FERC case No. EC-90-1 90) and PacifiCorp (U.S. Circuit Court of Appeals for D.C., 89-1333) decisions. Retail wheeling will benefit both consumers and producers. The ability of large customers to purchase power from the lowest cost sources and have it transmitted to their facilities, will save American industrial and commercial customers at least $15 billion annually. The Increased efficiency resulting from competition would also reduce residential electric bills. Through retail wheeling, independent power producers can market their capacity to a greater customer base, and traditional utilities will benefit from access to other utilities markets with the more efficient utilities prospering. Retail wheeling will, therefore, reward efficient utilities and encourage inefficient utilities to improve

  13. 2009 Tactical Wheeled Vehicles Conference (TWV)

    Science.gov (United States)

    2009-02-03

    fields. 5 ... Spent $265.2 Million in Reset of TWVs … or larger than the entire 2007 revenue of the Los Angeles Dodgers . ... Spent $265.2 Million in...Reset of T Vs or larger than the entire 2007 revenue of the Los Angeles Dodgers . ... Maintains over 29,000 Tactical Wheeled Vehicles in theater … or

  14. The Physics of Wheel-Rail Stability

    Science.gov (United States)

    Tan, B. T. G.

    2018-01-01

    This article discusses, at a simple level, the dynamics of the wheel-rail interface, which is fundamental to the stability of rail vehicles. The physics underlying this topic deserves to be better known by physicists and physics students, as it underpins such an important part of our technological infrastructure

  15. Reinventing the Wheel: The Economic Benefits of Wheeled Transportation in Early British Colonial West Africa

    OpenAIRE

    Isaías N. Chaves; Stanley L. Engerman; James A. Robinson

    2013-01-01

    One of the great puzzles of Sub-Saharan African economic history is that wheeled transportation was barely used prior to the colonial period. Instead, head porterage was the main method of transportation. The consensus among historians is that this was a rational adaption to the underlying conditions and factor endowments. In this paper we undertake the first systematic investigation of the relative costs of the different forms of wheeled transportation in Africa. We focus on calculating the ...

  16. A dynamic wheel-rail impact analysis of railway track under wheel flat by finite element analysis

    Science.gov (United States)

    Bian, Jian; Gu, Yuantong; Murray, Martin Howard

    2013-06-01

    Wheel-rail interaction is one of the most important research topics in railway engineering. It involves track impact response, track vibration and track safety. Track structure failures caused by wheel-rail impact forces can lead to significant economic loss for track owners through damage to rails and to the sleepers beneath. Wheel-rail impact forces occur because of imperfections in the wheels or rails such as wheel flats, irregular wheel profiles, rail corrugations and differences in the heights of rails connected at a welded joint. A wheel flat can cause a large dynamic impact force as well as a forced vibration with a high frequency, which can cause damage to the track structure. In the present work, a three-dimensional finite element (FE) model for the impact analysis induced by the wheel flat is developed by the use of the FE analysis (FEA) software package ANSYS and validated by another validated simulation. The effect of wheel flats on impact forces is thoroughly investigated. It is found that the presence of a wheel flat will significantly increase the dynamic impact force on both rail and sleeper. The impact force will monotonically increase with the size of wheel flats. The relationships between the impact force and the wheel flat size are explored from this FEA and they are important for track engineers to improve their understanding of the design and maintenance of the track system.

  17. Design of Wheeled Mobile Robot with Tri-Star Wheel as Rescue Robot

    Directory of Open Access Journals (Sweden)

    Rafiuddin Syam

    2014-10-01

    Full Text Available This study aims to design, and analyze a mobile robot that can handle some of the obstacles, they are uneven surfaces, slopes, can also climb stairs. WMR in this study is Tristar wheel that is containing three wheels for each set. On average surface only two wheels in contact with the surface, if there is an uneven surface or obstacle then the third wheel will rotate with the rotation center of the wheel in contact with the leading obstacle then only one wheel in contact with the surface. This study uses the C language program. Furthermore, the minimum thrust to be generated torque of the motor and transmission is 9.56 kg. The results obtained by calculation and analysis of DC motors used must have a torque greater than 14.67 kg.cm. Minimum thrust to be generated motor torque and the transmission is 9.56 kg. The experimental results give good results for robot to moving forward, backward, turn left, turn right and climbing the stairs.

  18. Microstructural and reliability in grinding of silicon nitride

    International Nuclear Information System (INIS)

    Liu, C.-C.

    2004-01-01

    A sintered Si 3 N 4 matrix has been characterized by TEM. The film thickness distribution of Si 3 N 4 was measured by high resolution transmission electron microscopy (HREM). Surface grinding is performed on two table speeds of 0.08 and 0.25 m s -1 with different depth of cut. The ground surfaces were observed with scanning electron microscopy (SEM). The surface texture was found to have greater dependence on depth of cut and table speed. The surface roughness is improved after smaller depth of cut. The flexural strength of ground specimens were measured by four-point flexure tests. The effect of depth of cut during grinding on the flexural strength and reliability of silicon nitride is investigated. The large depth of cut of 30 μm/pass resulted in a further decreased in strength of 540 MPa and a Weibull modulus of 7.5. When the depth of cut of 5 μm/pass were subjected to the ground specimens, the average strength was increased to 670 MPa and Weibull modulus to 9.1

  19. Kinematics and dynamics modelling of a mecanum wheeled mobile platform

    CSIR Research Space (South Africa)

    Tlale, NS

    2008-12-01

    Full Text Available analysis for mecanum wheeled mobile platform same time during the operation of the mobile platform, a maximum of eighty-one combinations of wheels (four wheels: 1,2, 3 and 4) and directions of rotational velocity of wheels (three directions of rotation... = I ’ (15) where ai is a constant depending on the wheel number and ai = -1 for i = 1 and 4, and ai = 1 for i = 2 and 3, T is the torque developed on the vehicle that changes the posture of the vehicle, I is the mass inertia of the vehicle...

  20. Study on the Attitude Control of Spacecraft Using Reaction Wheels

    Directory of Open Access Journals (Sweden)

    Ju-Young Du

    1998-06-01

    Full Text Available Attitude determination and control of satellite is important component which determines the accomplish satellite missions. In this study, attitude control using reaction wheels and momentum dumping of wheels are considered. Attitude control law is designed by Sliding control and LQR. Attitude maneuver control law is obtained by Shooting method. Wheels momentum dumping control law is designed by Bang-Bang control. Four reaction wheels are configurated for minimized the electric power consumption. Wheels control torque and magnetic moment of magnetic torquer are limited.

  1. Latent effectiveness of desiccant wheel: A silica gels- water system

    International Nuclear Information System (INIS)

    Rabah, A. A.; Mohamed, S. A.

    2009-01-01

    A latent heat effectiveness model in term of dimensionless groups? =f (NTU, m * ,Crm * ) for energy wheel has been analytically derived. The energy wheel is divided into humidification and dehumidification sections. For each section macroscopic mass differential equations for gas and the matrix were applied. In this process local latent effectiveness (? c ,? h ) for the humidification and dehumidification section of the wheel were obtained. The Latent effectiveness of the wheel is then derived form local effectiveness [? =f (? c ,? h)]. The model is compared with the existing experimental investigation and manufacturer data for energy wheel. More than 90% of the experimental data within a confidence limit of 95%. (Author)

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

    International Nuclear Information System (INIS)

    Lynch, T.W.

    1980-01-01

    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

  3. Complete Chiral Resolution Using Additive-Induced Crystal Size Bifurcation During Grinding

    NARCIS (Netherlands)

    Noorduin, Wim L.; Asdonk, Pim van der; Meekes, Hugo; Enckevort, Willem J.P. van; Kaptein, Bernard; Leeman, Michel; Kellogg, Richard M.; Vlieg, Elias

    2009-01-01

    Grinding them down: By using a tailor-made additive, even in the absence of racemization in solution, abrasive grinding can yield an enantiopure solid state. This novel chiral resolution technique is based on an asymmetric bifurcation in the crystal size distribution as a result of stereoselective

  4. Thermal model to investigate the temperature in bone grinding for skull base neurosurgery.

    Science.gov (United States)

    Zhang, Lihui; Tai, Bruce L; Wang, Guangjun; Zhang, Kuibang; Sullivan, Stephen; Shih, Albert J

    2013-10-01

    This study develops a thermal model utilizing the inverse heat transfer method (IHTM) to investigate the bone grinding temperature created by a spherical diamond tool used for skull base neurosurgery. Bone grinding is a critical procedure in the expanded endonasal approach to remove the cranial bone and access to the skull base tumor via nasal corridor. The heat is generated during grinding and could damage the nerve or coagulate the blood in the carotid artery adjacent to the bone. The finite element analysis is adopted to investigate the grinding-induced bone temperature rise. The heat source distribution is defined by the thermal model, and the temperature distribution is solved using the IHTM with experimental inputs. Grinding experiments were conducted on a bovine cortical bone with embedded thermocouples. Results show significant temperature rise in bone grinding. Using 50°C as the threshold, the thermal injury can propagate about 3mm in the traverse direction, and 3mm below the ground surface under the dry grinding condition. The presented methodology demonstrated the capability of being a thermal analysis tool for bone grinding study. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  5. The effect of grinding on magnetic properties of agglomereted MnFe2O4 nanoparticles

    International Nuclear Information System (INIS)

    Aslibeiki, B.; Kameli, P.; Salamati, H.

    2012-01-01

    The effects of grinding on interparticle magnetic interactions for an ensemble of agglomerated MnFe 2 O 4 nanoparticles have been studied. Structural analyses showed that by grinding the samples, a small variation in size of crystallites and lattice strain will occur. ac Magnetic susceptibility measurements under different conditions and spin dynamics analysis suggest that freezing temperature is frequency dependent and it is in good agreement with critical slowing down model. This is an indication that these nanoparticles have superspin glass behavior. The estimated zυ and τ 0 parameters using critical slowing down model show that by increasing the grinding time the interaction between nanoparticles decreases. ac Susceptibility measurements in cooling and heating process show a thermal hysteresis. The thermal hysteresis decreased by increasing the grinding time. Also, the thermal hysteresis is frequency dependent and it increased as frequency decreased. These results showed that interparticle interactions such as dipole-dipole and exchange interactions between nanoparticles become weaker by grinding. - Highlights: → We studied the effects of grinding on interparticle interactions of MnFe 2 O 4 nanoparticles. → Critical slowing model used to estimate the interparticle interaction strength. → The results showed interparticle interactions become weaker by grinding. → Ac Susceptibility shows the irreversibility of spins decreased by grinding.

  6. Effect of Grinding on the Solid-State Stability and Particle Dissolution of Acyclovir Polymorphs.

    Science.gov (United States)

    Magnoni, Federico; Gigliobianco, Maria Rosa; Vargas Peregrina, Dolores; Censi, Roberta; Di Martino, Piera

    2017-10-01

    The present work investigated the solid state change of 4 acyclovir polymorphs when ground at room temperature (Method A) and under cryo-grinding in the presence of liquid nitrogen (Method B). Modifications in particle size and shape (evaluated by scanning electron microscopy) and in the water content (evaluated by thermal analysis) were related to transitions at the solid state, as confirmed by X-ray powder diffractometry. Anhydrous Form I was stable under grinding by both Methods A and B. The anhydrous Form II was stable during grinding under Method A, whereas it was progressively converted to the hydrate Form V during grinding under Method B. The hydrate Form V was stable under Method A, whereas it was converted to the anhydrous Form I after 15 min and then to the hydrate Form VI after 45 min of grinding. The hydrate Form VI proved to be stable under grinding by both Methods A and B. Thus, Form I and VI were the only forms that yielded a sizeable decrease in particle size under grinding, with a consequent increase in particle dissolution rate, while maintaining solid state physicochemical stability. Form I treated under Method B grinding gave the best dissolution rate. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  7. The Running Wheel Enhances Food Anticipatory Activity: An Exploratory Study.

    Science.gov (United States)

    Flôres, Danilo E F L; Bettilyon, Crystal N; Jia, Lori; Yamazaki, Shin

    2016-01-01

    Rodents anticipate rewarding stimuli such as daily meals, mates, and stimulant drugs. When a single meal is provided daily at a fixed time of day, an increase in activity, known as food anticipatory activity (FAA), occurs several hours before feeding time. The factors affecting the expression of FAA have not been well-studied. Understanding these factors may provide clues to the undiscovered anatomical substrates of food entrainment. In this study we determined whether wheel-running activity, which is also rewarding to rodents, modulated the robustness of FAA. We found that access to a freely rotating wheel enhanced the robustness of FAA. This enhancement was lost when the wheel was removed. In addition, while prior exposure to a running wheel alone did not enhance FAA, the presence of a locked wheel did enhance FAA as long as mice had previously run in the wheel. Together, these data suggest that FAA, like wheel-running activity, is influenced by reward signaling.

  8. ON THE DYNAMIC VERTICAL WHEEL-RAIL FORCES AT LOW FREQUENCIES

    Directory of Open Access Journals (Sweden)

    Mădălina DUMITRIU

    2012-05-01

    Full Text Available To homologate the railay vehicles, from the pespective of dynamic behavior, the dynamic forces generated at the wheel/rail interface should be limited, in order to comply with the criterion regarding the rolling track fatigue. The meeting of this requirement implies the vehicle adjustment in its construction. This paper examines the influence of certain vehicle parameters upon the magnitude of the dynamic vertical loads derived during travelling on a track with random irregularities. It will be shown how the minimizing condition of the dynamic vertical loads can result into the best primary suspension damping

  9. Preparation of Grinding Aid Using Waste Acid Residue from Plasticizer Plant

    Science.gov (United States)

    Li, Lingxiao; Feng, Yanchao; Liu, Manchao; Zhao, Fengqing

    2017-09-01

    The grinding aid for granulated blast-furnace slag were prepared from waste acid residue from plasticizer plant through neutralization, de-methanol and granulation process. In this process, sulfuric acid was transformed into gypsum which has much contribution for grinding effect by combined use with the glycerol and poly glycerin in the waste. Fly ash was used for granulation for the composite grinding aid. Methanol can be recycled in the process. The result showed that the suitable addition of grinding aid is 0.03 % of granulated blast-furnace slag (mass). In this case, the specific surface area is 14% higher than that of the blank. Compared with the common grinding aids, it has excellent performance and low cost.

  10. Work Index and Grinding Energy Assessment of Dilband Iron Ore, Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad Ishaque Abro

    2011-01-01

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

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

    DEFF Research Database (Denmark)

    Rehder, Sönke; Klukkert, Marten; Löbmann, Korbinian

    2011-01-01

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

  12. Surface crack formation on rails at grinding induced martensite white etching layers

    DEFF Research Database (Denmark)

    Rasmussen, Carsten Jørn; Fæster, Søren; Dhar, Somrita

    2017-01-01

    The connection between profile grinding of rails, martensite surface layers and crack initiation has been investigated using visual inspection, optical microscopy and 3D X-ray computerized tomography. Newly grinded rails were extracted and found to be covered by a continuous surface layer...... of martensite with varying thickness formed by the grinding process. Worn R350HT and R200 rails were extracted from the Danish rail network as they had transverse bands resembling grinding marks on the running surface. The transverse bands were shown to consist of martensite which had extensive crack formation...... at the martensite/pearlite interface. The cracks in R350HT propagated down into the rail while those in the soft R200 returned to the surface causing only very small shallow spallation. The transverse bands had the same shape, size, orientation, location and periodicity which would be expected from grinding marks...

  13. Grinding patterns in migraine patients with sleep bruxism: a case-controlled study.

    Science.gov (United States)

    Kato, Momoko; Saruta, Juri; Takeuchi, Mifumi; Sugimoto, Masahiro; Kamata, Yohei; Shimizu, Tomoko; To, Masahiro; Fuchida, Shinya; Igarashi, Hisaka; Kawata, Toshitsugu; Tsukinoki, Keiichi

    2016-11-01

    Details on grinding patterns and types of contact during sleep bruxism in association with migraine headache have not yet been elucidated. This study compared the characteristics of sleep bruxism between patients with migraine and controls. The study included 80 female patients who had been diagnosed with migraine and 52 women with no history of migraine. Grinding patterns were measured using the BruxChecker® (Scheu Dental, Iserlohn, Germany). There was a significant difference between the two groups in the distribution of grinding patterns at the laterotrusive side (p grinding area at all sites was significantly larger in the migraine group than in the control group (p grinding over a large area among migraine patients, particularly in the molar region.

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Keith Gordon

    2011-10-01

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

  16. Effect of simulated chairside grinding procedures using commercially available abrasive agents on the surface properties of zirconia

    OpenAIRE

    Sandhu, Ramandeep; Kheur, Mohit; Kheur, Supriya

    2017-01-01

    Aim: The aim of the present study was to assess the change in physical properties (surface roughness, surface hardness and phase transformation) after surface grinding of zirconia by using three commercially available abrasives. Materials and Methods: Thirty sintered zirconia specimens were prepared and divided into three groups namely Group M (grinded using Mani Dia diamond bur standard grit), Group T (grinded using Tri Hawk diamond bur coarse grit) and Group P (grinded using Predator car...

  17. Wheel traffic effect on air-filled porosity and air permeability in a soil catena across the wheel rut

    DEFF Research Database (Denmark)

    Berisso, Feto Esimo; Schjønning, Per; Lamandé, Mathieu

    might induce different effects on soil physical properties. The objective of this study was to investigate the impact of vehicle traffic on soil physical properties and air permeability by systematic collection of samples in a transect running from the center to the outside of the wheel rut. A field...... catena running from center of the wheel rut to un wheeled part of the field ( 0, 20, 40, 50,60 and 400 cm horizontal distance). We measured water retention and air permeability (ka) at -30, -100 and -300 hPa matric potentials. At -100 hPa, we obtained consistently lower air filled under the wheel rut......The impact of wheel traffic on soil physical properties is usually quantified by randomly collecting soil cores at specific depths below the wheeled surface. However, modeling studies as well as few measurements indicated a non-uniform stress distribution in a catena across the wheel rut, which...

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

    Science.gov (United States)

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

  19. Simulation and energy efficiency analysis of desiccant wheel systems for drying processes

    International Nuclear Information System (INIS)

    De Antonellis, Stefano; Joppolo, Cesare Maria; Molinaroli, Luca; Pasini, Alberto

    2012-01-01

    In drying processes it is necessary to appropriately control air humidity and temperature in order to enhance water evaporation from product surface. The aim of this work is to investigate several HVAC configurations for product drying based on desiccant wheels, in order to find systems which reach high primary energy savings through the appropriate integration of refrigerating machines, adsorption wheels and cogenerative engines. Simulations are carried out for different values of sensible to latent ambient load ratio and the effect of ambient and outside air conditions is evaluated for each configuration. It is shown that primary energy savings can reach 70–80% compared to the reference technology based on a cooling coil. With respect to works available in literature, the results of this study keep a general approach and they can be used as a simple tool for preliminary assessment in a wide range of applications. -- Highlights: ► Several HVAC systems for product drying based on desiccant wheels are investigated. ► The sensible to latent ambient load ratio influences the choice of the best system. ► Energy savings can reach 80% compared to the technology based on a cooling coil. ► Simulation results can be used for preliminary assessment in many applications.

  20. Advanced Control of Wheeled Inverted Pendulum Systems

    CERN Document Server

    Li, Zhijun; Fan, Liping

    2013-01-01

    Advanced Control of Wheeled Inverted Pendulum Systems is an orderly presentation of recent ideas for overcoming the complications inherent in the control of wheeled inverted pendulum (WIP) systems, in the presence of uncertain dynamics, nonholonomic kinematic constraints as well as underactuated configurations. The text leads the reader in a theoretical exploration of problems in kinematics,dynamics modeling, advanced control design techniques,and trajectory generation for WIPs. An important concern is how to deal with various uncertainties associated with the nominal model, WIPs being characterized by unstable balance and unmodelled dynamics and being subject to time-varying external disturbances for which accurate models are hard to come by.   The book is self-contained, supplying the reader with everything from mathematical preliminaries and the basic Lagrange-Euler-based derivation of dynamics equations to various advanced motion control and force control approaches as well as trajectory generation met...