WorldWideScience

Sample records for wear

  1. Eye Wear

    Science.gov (United States)

    Eye wear protects or corrects your vision. Examples are Sunglasses Safety goggles Glasses (also called eyeglasses) Contact ... jobs and some sports carry a risk of eye injury. Thousands of children and adults get eye ...

  2. Tooth wear

    Directory of Open Access Journals (Sweden)

    Tušek Ivan

    2014-01-01

    Full Text Available Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction, which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to tooth abfraction and microfracture. Wear of tooth surfaces due to the presence of microscopic imperfections of tooth surfaces is clinically manifested as sanding veneers. Tribology, as an interdisciplinary study of the mechanisms of friction, wear and lubrication at the ultrastructural level, has defined a universal model according to which the etiopathogenesis of tooth wear is caused by the following factors: health and diseases of the digestive tract, oral hygiene, eating habits, poor oral habits, bruxism, temporomandibular disorders and iatrogenic factors. Attrition and dental erosion are much more common in children with special needs (Down syndrome. Erosion of teeth usually results from diseases of the digestive tract that lead to gastroesophageal reflux (GER of gastric juice (HCl. There are two basic approaches to the assessment of the degree of wear and dental erosion. Depending on the type of wear (erosion, attrition, abfraction, the amount of calcium that was realised during the erosive attack could be determined qualitatively and quantitatively, or changes in optical properties and hardness of enamel could be recorded, too. Abrasion of teeth (abrasio dentium is the loss of dental hard tissue caused by friction between the teeth and exogenous foreign substance. It is most commonly provoked by prosthetic dentures and bad habits, while its effect depends on the size of abrasive particles and their amount, abrasive particle hardness and hardness of tooth

  3. Wearing gloves in the hospital

    Science.gov (United States)

    ... gloves; PPE - wearing gloves; Nosocomial infection - wearing gloves; Hospital acquired infection - wearing gloves ... Wearing gloves in the hospital helps prevent the spread of germs. This helps protect both patients and health care workers from infection.

  4. Comparative wear mapping techniques

    DEFF Research Database (Denmark)

    Alcock, J.; Sørensen, Ole Toft; Jensen, S.

    1996-01-01

    Pin-on-disc tests of tungsten carbide pins against silicon carbide discs were performed and wear rate, mechanism and friction maps constructed. Correlations were observed between the wear mode and the friction of the pin-disc interface, and between the qualitative incidence of disruptive wear...

  5. Wear Debris Analysis:Fundamental Principle of Wear-Graphy

    Institute of Scientific and Technical Information of China (English)

    陈铭; 王伟华; 殷勇辉; 王成焘

    2004-01-01

    A new wear-graphy technology was developed, which can simultaneously identify the shape and composition of wear debris, for both metals and non-metals.The fundamental principles of the wear-graphy system and its wear-gram system are discussed here.A method was developed to distribute wear debris on a slide uniformly to reduce overlapping of wear debris while smearing.The composition identification analyzes the wear debris using the scanning electron microscope (SEM) energy spectrum, infrared-thermal imaging and X-ray imaging technology.A wear debris analysis system based on database techniques is demonstrated, and a visible digitized wear-gram is acquired based on the information of wear debris with image collection and processing of the wear debris.The method gives the morphological characteristics of the wear debris, material composition identification of the wear debris, intelligent recognition of the wear debris, and storage and management of wear debris information.

  6. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup......Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  7. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  8. Optical wear monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kidane, Getnet S; Desilva, Upul P.; He, Chengli; Ulerich, Nancy H.

    2016-07-26

    A gas turbine includes first and second parts having outer surfaces located adjacent to each other to create an interface where wear occurs. A wear probe is provided for monitoring wear of the outer surface of the first part, and includes an optical guide having first and second ends, wherein the first end is configured to be located flush with the outer surface of the first part. A fiber bundle includes first and second ends, the first end being located proximate to the second end of the optical guide. The fiber bundle includes a transmit fiber bundle comprising a first plurality of optical fibers coupled to a light source, and a receive fiber bundle coupled to a light detector and configured to detect reflected light. A processor is configured to determine a length of the optical guide based on the detected reflected light.

  9. Comparative wear mapping techniques

    DEFF Research Database (Denmark)

    Alcock, J.; Sørensen, Ole Toft; Jensen, S.

    1996-01-01

    Pin surfaces were analysed by laser profilometry. Two roughness parameters, R(a) and the fractal dimension, were investigated as a first step towards methods of quantitative wear mechanism mapping. Both parameters were analysed for their relationship to the severity and prevalence of a mechanism....

  10. Assessment of wear facets produced by the ACTA wear machine

    DEFF Research Database (Denmark)

    Benetti, Ana R; Larsen, Liselotte; Dowling, Adam H

    2016-01-01

    OBJECTIVE: To investigate the use of a three-dimensional (3D) digital scanning method in determining the accuracy of the wear performance parameters of resin-based composites (RBCs) determined using a two-dimensional (2D) analogue methodology following in-vitro testing in an Academisch Centrum...... an assessment of the potential of the experimental RBC formulations for clinical usage. CONCLUSION: The 3D technique allowed for the assessment of mean maximum wear depth and mean total volumetric wear which enables tribological analyses of the wear facet and therefore the wear mechanisms operative. Employing...... profilers is useful when screening potential new RBC formulations for the restoration of posterior dentition....

  11. Wear Resistance and Wear Mechanism of a Hot Dip Aluminized Steel in Sliding Wear Test

    Science.gov (United States)

    Xue, Zhiyong; Hao, Xiaoyang; Huang, Yao; Gu, Lingyun; Ren, Yu; Zheng, Ruipeng

    2016-12-01

    Sliding wear experiments were conducted on a hot dip aluminized steel to investigate its wear resistance and wear mechanism. The wear tests were also carried out on a hot dip galvanized steel and the base material (steel Q345) as a comparison. Results show that the wear resistance and hardness of the hot dip aluminized steel are significantly higher than that of the hot dip galvanized steel and the steel Q345 at room temperature. The better wear resistance of the hot dip aluminized steel attributes mainly to the formation of a transition layer containing abundant Fe-Al intermetallic compounds and the transformation of wear-resisting oxides during the friction process. The main phase in the transition layer is Fe2Al5. The thickness of the transition layer is about 90-120 μm. When the wear load increases from 3 N to 19 N, the wear type of the aluminized layer transform from adhesive wear (3 N) into abrasive wear (7 N) and finally into slight wear mixed with oxidation (higher than 11 N).

  12. TIRE WEAR MODELING

    Directory of Open Access Journals (Sweden)

    Rosen IVANOV

    2016-09-01

    Full Text Available On the basis of a known relationship, an enhanced model for specific tire wear per kilometer has been developed. It is appropriate for practical use - for evaluation of the influence of different factors. Two types of experiments have been carried out with a testing device - one without sideslip, but with a known longitudinal slip, and the other one with the same longitudinal slip but also with a known sideslip. As a result, the coefficients of the proportion of the developed model have been evaluated. After the model validation, an analytical investigation concerning the influence of tire pressure, sideslip and longitudinal slip on the tire wear has been carried out. The results are presented graphically.

  13. Engine oil wear resistance

    Directory of Open Access Journals (Sweden)

    A.N. Farhanah

    2015-03-01

    Full Text Available Lubricants play a vital role in an internal combustion engine to lubricate parts and help to protect and prolong the engine life. Lubricant also will help to reduce wear by creating lubricating film between the moving parts hence reduce metal-to-metal contacts. Engine oil from three different manufacturers with the same SAE viscosity grade available in market does not mean it will have the same lubricity for an engine. In this study, commercial mineral lubrication oil (SAE 10W-30 from three manufacturers was investigated to compare the lubrication performance at three different temperatures (40˚C, 70˚C and 100˚C in 60 minutes time duration by using four ball wear tester. The speed will be varied from 1000 rpm to 2500 rpm. Results show that all three lubricants have different lubricity performance; the smaller the wear scar, the better the lubricant since the lubricant can protect the moving surfaces from direct metal-to-metal contact occur.

  14. Pure mechanical wear loss measurement in corrosive wear

    Indian Academy of Sciences (India)

    Yanliang Huang; Xiaoxia Jiang; Sizuo Li

    2000-12-01

    The method for the measurement of the pure mechanical wear loss for 321 stainless steel, 1045 steel and pure iron in the study of the synergy between corrosion and wear was studied. The methods studied included the measurement in distilled water, by cathodic protection and by adding inhibitor KI, and all were compared with the wear loss in air. The experiment showed that the pure mechanical wear losses and friction coefficients obtained by the three methods were close to each other and can be used to calculate the various wear components in the study of the interaction of corrosion and wear, but the measurements in distilled water for pure iron and 1045 steel are not recommended due to their corrosion.

  15. Friction and wear calculation methods

    CERN Document Server

    Kragelsky, I V; Kombalov, V S

    1981-01-01

    Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a

  16. Wear of polymers and composites

    CERN Document Server

    Abdelbary, Ahmed

    2015-01-01

    In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

  17. Wear of micro end mills

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2005-01-01

    This paper addresses the important issue of wear on micro end mills considering relevant metrological tools for its characterization and quantification. Investigation of wear on micro end mills is particularly difficult and no data are available in the literature. Small worn volumes cause large d...

  18. [Infants wearing teething necklaces].

    Science.gov (United States)

    Taillefer, A; Casasoprana, A; Cascarigny, F; Claudet, I

    2012-10-01

    Numerous infants wear teething necklaces, a quack remedy with a real risk of strangulation or aspiration of small beads. Evaluate parental perceptions and beliefs about the use of teething necklaces and analyze parental knowledge about the associated dangers. Between March and July 2011, in three different pediatric units of a tertiary children's hospital and a general hospital in Toulouse and Montauban (southwest France), voluntary parents were invited to be interviewed about their child wearing a teething necklace. The interviews were conducted following an anthropological approach: they were recorded and then fully transcribed and analyzed. Parents were informed that the conversation was recorded. During the study period, 48 children were eligible. Eleven families refused to participate, 29 parents were interviewed face to face. The children's mean age was 14 years ± 7 months, the male:female ratio was equal to 0.8 (12 boys, 15 girls). The mean age of children when necklace wearing was started was equal to 4 ± 2 months. The mean mother's age was 31 ± 5 years and 33 ± 4 years for fathers. The parents' religion was mostly Catholic (60%). Teething necklaces were mainly made of amber (n=23). Sales information about the risks associated with the necklaces was for the most part absent (92%). The most frequent positive parental perceptions were analgesic properties and a soothing remedy (73%); a birth accessory and memory (64%); an esthetic accessory (60%); a protective amulet (60%); and an alternative or additional element to other traditional therapeutics (55%). The negative parental perceptions (n=4) were an unnecessary accessory, costume jewelry, a pure commercial abuse of a popular belief, a dangerous item with a risk of strangulation, and the absence of proof of its efficacy. Although parents concede that teeth eruption is benign, they fear its related symptoms. To a natural phenomenon a natural response: they use a necklace to satisfy the analogy. The

  19. Switch wear leveling

    Science.gov (United States)

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

    2015-09-01

    An apparatus for switch wear leveling includes a switching module that controls switching for two or more pairs of switches in a switching power converter. The switching module controls switches based on a duty cycle control technique and closes and opens each switch in a switching sequence. The pairs of switches connect to a positive and negative terminal of a DC voltage source. For a first switching sequence a first switch of a pair of switches has a higher switching power loss than a second switch of the pair of switches. The apparatus includes a switch rotation module that changes the switching sequence of the two or more pairs of switches from the first switching sequence to a second switching sequence. The second switch of a pair of switches has a higher switching power loss than the first switch of the pair of switches during the second switching sequence.

  20. Low friction wear resistant graphene films

    Science.gov (United States)

    Sumant, Anirudha V.; Berman, Diana; Erdemir, Ali

    2017-02-07

    A low friction wear surface with a coefficient of friction in the superlubric regime including graphene and nanoparticles on the wear surface is provided, and methods of producing the low friction wear surface are also provided. A long lifetime wear resistant surface including graphene exposed to hydrogen is provided, including methods of increasing the lifetime of graphene containing wear surfaces by providing hydrogen to the wear surface.

  1. Tool wear mechanism in turning of novel wear-resisting aluminum bronze

    Institute of Scientific and Technical Information of China (English)

    倪东惠; 夏伟; 张大童; 郭国文; 邵明

    2003-01-01

    Tool wear and wear mechanism during the turning of a wear-resisting aluminum bronze have been stud-ied. Tool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turn a novelhigh strength, wear resisting aluminum bronze without coolant and lubricant. Adhesion of workpiece materials wasfound on tool's surface. Under the turning condition used in this study major wear mechanisms for turning aluminumbronze using M2 high-speed steel tool are diffusion wear, adhesive wear and plastic deformation and shear on thecrater. Partial melting of high-speed steel on the rake plays a role in the tool wear also. Major wear mechanisms forturning aluminum bronze using YW1 cemented carbide tool are diffusion wear, attrition wear and sliding wear. Tocontrol the machining temperature is essential to reduce tool wear.

  2. They shall wear fringes.

    Science.gov (United States)

    Sugar, M

    1999-01-01

    The multiple functions of clothes include utility, protection, rivalry, disguise, camouflage, display for seduction purposes, aggression, totemism, and status. Here the focus is on a decorative and distinctive hierarchical aspect of ancient dress, the tsitsit or fringes, whose original function is long absent, but that has endured for 3,500 years in Judaism. The beginning of their use beyond the totemic appears related to issues of changing identity from slavery to liberty, endowing noble status, exhibitionism, a symbol of identity, identification with the aggressor, a talisman, and potency. It is conceptualized that they became a symbol, or a specifier, that helped promote group cohesion in ex-slaves who were frightened, dependent, anxious, and not hopeful about their future. The tsitsit aided the development of a new identity and made all Israelites equal and noble to the observer. The durability of this symbol to the present is evident in its daily wear, as an accompaniment to daily prayers, as well as in its use as a burial shroud for males. It appears that the tsitsit have additional multiple functions. These are the promise of oral and genital satisfaction, and the pleasure of the after-life, superego warnings and control of sexual impulses, protection, survival value, and affirmation. Since they offer sublimation with acceptable gratification of instincts, the tsitsit have become ritualized and endure.

  3. Intelligent Detection of Drill Wear

    Science.gov (United States)

    Liu, T. I.; Chen, W. Y.; Anatharaman, K. S.

    1998-11-01

    Backpropagation neural networks (BPNs) were used for on-line detection of drill wear. The neural network consisted of three layers: input, hidden, and output. The input vector comprised drill size, feed rate, spindle speed, and eight features obtained by processing the thrust and torque signals. The output was the drill wear state which either usable or failure. Drilling experiments with various drill sizes, feed rates and spindle speeds were carried out. The learning process was performed effectively by utilising backpropagation with smoothing and an activation function slope. The on-line detection of drill wear states using BPNs achieved 100% reliability even when the drill size, feed rate and spindle speed were changed. In other words, the developed on-line drill wear detection systems have very high robustness and hence can be used in very complex production environments, such as flexible manufacturing systems.

  4. Wear resistance properties of austempered ductile iron

    Science.gov (United States)

    Lerner, Y. S.; Kingsbury, G. R.

    1998-02-01

    A detailed review of wear resistance properties of austempered ductile iron (ADI) was undertaken to examine the potential applications of this material for wear parts, as an alternative to steels, alloyed and white irons, bronzes, and other competitive materials. Two modes of wear were studied: adhesive (frictional) dry sliding and abrasive wear. In the rotating dry sliding tests, wear behavior of the base material (a stationary block) was considered in relationship to countersurface (steel shaft) wear. In this wear mode, the wear rate of ADI was only one-fourth that of pearlitic ductile iron (DI) grade 100-70-03; the wear rates of aluminum bronze and leaded-tin bronze, respectively, were 3.7 and 3.3 times greater than that of ADI. Only quenched DI with a fully martensitic matrix slightly outperformed ADI. No significant difference was observed in the wear of steel shafts running against ADI and quenched DI. The excellent wear performance of ADI and its countersurface, combined with their relatively low friction coefficient, indicate potential for dry sliding wear applications. In the abrasive wear mode, the wear rate of ADI was comparable to that of alloyed hardened AISI 4340 steel, and approximately one-half that of hardened medium-carbon AISI 1050 steel and of white and alloyed cast irons. The excellent wear resistance of ADI may be attributed to the strain-affected transformation of high-carbon austenite to martensite that takes place in the surface layer during the wear tests.

  5. The Delamination Theory of Wear

    Science.gov (United States)

    1974-09-01

    junctions, it is still based on the assumption that the deformation occurs at the asperities. Rabinowicz [14] advanced an adhesion theory of friction...shown that bronze particles were indeed bigger than steel particles. The compilation of wear particle sizes given by Rabinowicz [14] also indicates...Waterhouse [32] has shown that, in fact, fretting occurs by delamination. 6) Minimum Load for Loose Particle Formation Rabinowicz [14] found that no wear

  6. The fractal characterization of wear particles in relation to the wear status

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The topography and distribution of wear particles produced in the wear process containmuch information about the wear status. Fractal geometry is applied in this paper to describe thewear particle accumulation in order to characterize the wear status change. The sliding wear test isperformed on a pin-on-disc apparatus using steel disc and brass pin. The investigation resultsshow that wear particle accumulation presents a strong bi-fractal behavior. Also, the fractal dimen-sion varies in correspondence to the wear status change. A new fractal index characterizing thewear particle accumulation is put forward. The wear tests of brass pin demonstrate that the fractalindex is effective in describing the wear status change.

  7. Wear behaviour of Al 261

    Directory of Open Access Journals (Sweden)

    N. Mathan Kumar

    2016-03-01

    Full Text Available Al 2618 matrix material was mixed with the Silicon Nitride (Si3N4, Aluminium Nitride (AlN and Zirconium Boride (ZrB2 reinforced particles. AMC was synthesized successfully by the stir casting method with the various X-wt.% of reinforcements (X = 0,2,4,6,8. Tribological behaviour was studied in this composite with various temperature conditions. The working conditions were Temperature (°C, Load (N, Velocity (m/s and Sliding Distances (m. Before wear testing the mechanical behaviour has been analysed. EDAX was confirmed by the matrix material composition. The Al 2618 alloy and the reinforcement mixers were confirmed by the X-ray Diffraction analysis. Wear rate (mm3/m, Wear resistance (m/mm3, Specific Wear rate (m/Nm and Co-efficient of friction (μ were analysed with various conditions. The worn surfaces were analysed before and after wear testing by Scanning Electron Microscope (SEM. Influence of process parameters and Percentage of contribution were analysed by Taguchi and Analysis of Variance (ANOVA methods. Genetic Algorithm (GA was adopted for optimizing the best and mean of the wear rate and to identify the exact influence of input parameters.

  8. Critical component wear in heavy duty engines

    CERN Document Server

    Lakshminarayanan, P A

    2011-01-01

    The critical parts of a heavy duty engine are theoretically designed for infinite life without mechanical fatigue failure. Yet the life of an engine is in reality determined by wear of the critical parts. Even if an engine is designed and built to have normal wear life, abnormal wear takes place either due to special working conditions or increased loading.  Understanding abnormal and normal wear enables the engineer to control the external conditions leading to premature wear, or to design the critical parts that have longer wear life and hence lower costs. The literature on wear phenomenon r

  9. Calculation of wear (f.i. wear modulus) in the plastic cup of a hip joint prosthesis

    NARCIS (Netherlands)

    Ligterink, D.J.

    1975-01-01

    The wear equation is applied to the wear process in a hip joint prosthesis and a wear modulus is defined. The sliding distance, wear modulus, wear volume, wear area, contact angle and the maximum normal stress were calculated and the theoretical calculations applied to test results. During the wear

  10. Multiscale Modeling of Wear Degradation

    KAUST Repository

    Moraes, Alvaro

    2014-01-06

    Cylinder liners of diesel engines used for marine propulsion are naturally subjected to a wear process, and may fail when their wear exceeds a specified limit. Since failures often represent high economical costs, it is utterly important to predict and avoid them. In this work [4], we model the wear process using a pure jump process. Therefore, the inference goal here is to estimate: the number of possible jumps, its sizes, the coefficients and the shapes of the jump intensities. We propose a multiscale approach for the inference problem that can be seen as an indirect inference scheme. We found that using a Gaussian approximation based on moment expansions, it is possible to accurately estimate the jump intensities and the jump amplitudes. We obtained results equivalent to the state of the art but using a simpler and less expensive approach.

  11. Multiscale Modeling of Wear Degradation

    KAUST Repository

    Moraes, Alvaro

    2016-01-06

    Cylinder liners of diesel engines used for marine propulsion are naturally subjected to a wear process, and may fail when their wear exceeds a specified limit. Since failures often represent high economical costs, it is utterly important to predict and avoid them. In this work [4], we model the wear process using a pure jump process. Therefore, the inference goal here is to estimate: the number of possible jumps, its sizes, the coefficients and the shapes of the jump intensities. We propose a multiscale approach for the inference problem that can be seen as an indirect inference scheme. We found that using a Gaussian approximation based on moment expansions, it is possible to accurately estimate the jump intensities and the jump amplitudes. We obtained results equivalent to the state of the art but using a simpler and less expensive approach.

  12. Multiscale Modeling of Wear Degradation

    KAUST Repository

    Moraes, Alvaro

    2015-01-07

    Cylinder liners of diesel engines used for marine propulsion are naturally subjected to a wear process, and may fail when their wear exceeds a specified limit. Since failures often represent high economical costs, it is utterly important to predict and avoid them. In this work [4], we model the wear process using a pure jump process. Therefore, the inference goal here is to estimate: the number of possible jumps, its sizes, the coefficients and the shapes of the jump intensities. We propose a multiscale approach for the inference problem that can be seen as an indirect inference scheme. We found that using a Gaussian approximation based on moment expansions, it is possible to accurately estimate the jump intensities and the jump amplitudes. We obtained results equivalent to the state of the art but using a simpler and less expensive approach.

  13. Erosive Wear and Wear Mechanism of in situ TiCp/Fe Composites

    Institute of Scientific and Technical Information of China (English)

    Zhaojing LIU; Zhiliang NING; Fengzhen LI; Xiurong YAO; Shanzhi REN

    2005-01-01

    The base structure of in situ TiCP/Fe composites fabricated under industrial condition was changed by different heat treatments. Erosive wear tests were carried out and the results were compared with that of wear-resistant white cast iron. The results suggest that the wear resistance of the in situ TiCp/Fe composite is higher than that of wear-resistant white cast iron under the sand erosive wear condition. The wear mechanism of the wear-resistant white cast iron was a cycle process that base surface was worn and carbides were exposed, then carbides was broken and wear pits appeared. While the wear mechanism of in situ TiCp/Fe composite was a cycle process that base surface was worn and TiC grains were exposed and dropped. The wear resistance of in situ TiCp/Fe composite was lower than that of wear-resistant white cast iron under the slurry erosive wear condition. Under such circumstance,the material was not only undergone erosive wear but also electrochemistry erosion due to the contact with water in the medium. The wear behaviours can be a combination of two kinds of wear and the sand erosive wear is worse than slurry erosive wear.

  14. Should School Nurses Wear Uniforms?

    Science.gov (United States)

    Journal of School Health, 2001

    2001-01-01

    This 1958 paper questions whether school nurses should wear uniforms (specifically, white uniforms). It concludes that white uniforms are often associated with the treatment of ill people, and since many people have a fear reaction to them, they are not necessary and are even undesirable. Since school nurses are school staff members, they should…

  15. Tooth wear patterns in the deciduous dentition.

    Science.gov (United States)

    Warren, John J; Yonezu, Takuro; Bishara, Samir E

    2002-12-01

    Tooth wear is common in the deciduous dentition. A recent study suggests that tooth wear in the deciduous dentition is related to subsequent tooth wear in adults, so that early identification of factors related to tooth wear could be of long-term benefit. The purposes of this study were to describe patterns of tooth wear in the deciduous dentition and to relate tooth wear to occlusal characteristics and longitudinal dietary patterns. Data were collected as part of a longitudinal study of a cohort of children recruited at birth from Iowa hospitals. Stone casts were obtained in the deciduous dentition stage, and 355 children, 4 to 5 years old, met the selection criteria. Tooth wear was categorized for each tooth as none, mild, moderate, or severe, and related to occlusal characteristics and longitudinal data on fruit juice and soft drink consumption. All children exhibited some tooth wear on at least 1 tooth, and nearly 16% of them had at least 1 tooth with severe wear. Tooth wear was generally more severe in the maxillary arch and the anterior teeth. Severe tooth wear on the molars was significantly related to posterior crossbites, but severe tooth wear on the incisors was related to Class III canine relationships. There were no statistically significant relationships between tooth wear and soft drink or fruit juice consumption. Based on our results, we concluded that mild tooth wear is universal in the deciduous dentition, but only a few occlusal factors are related to severe tooth wear. Tooth wear was not related to any dietary patterns we investigated.

  16. Improvements of harrows wear resistance

    Directory of Open Access Journals (Sweden)

    Warouma Arifa

    2015-12-01

    Full Text Available Wear is the main reason for the loss of performance of the parts for agricultural machinery. It leads to the degradation of the soil working quality. This work aims to highlight the wear resistance of the harrows discs manufactured, consolidated and sharpened differently. The tests were conducted in the laboratory and the field of the Faculty of Exploitation and Repair of Agricultural Machinery of the State Technical University of Kirovograd (Ukraine in 2015. The technical equipment consists of devices for consolidation by electric discharge and for measurement the linear wear of discs, a harrow, a sand test bed, a tractor and discs made of different materials and technologies. Some parameterized were collected during the laboratory test each 5 ha and up to 20 ha of operation and in the fields each 30 ha until the time limit of exploitation. The Laboratory tests have shown that after twenty (20 ha of operation, the wear resistance of the experimental discs made of steel 65G and consolidated by electric discharge with simultaneous grinding (sharpening angle of 30° is 2.95 times higher than the discs in series made of steel 28MnB5. The field experiment gave the following results: According to agro technical requirements, the plowing depth limit of serial discs made of steel 28MnB5 was reached after an operating duration of 120 ha while for experimental discs made of steel 65G and consolidated by electric discharge with simultaneous grinding (sharpening angle of 30 degrees this duration is of 156 ha. The diameter wear limit of experimental discs was reached after an operating duration of 179 ha against 154 ha for the serial ones. Therefore, the new technology can be applied during the manufacture and / or the repair of the discs.

  17. Needs and challenges in precision wear measurement

    Energy Technology Data Exchange (ETDEWEB)

    Blau, P.J.

    1996-01-10

    Accurate, precise wear measurements are a key element in solving both current wear problems and in basic wear research. Applications range from assessing durability of micro-scale components to accurate screening of surface treatments and thin solid films. Need to distinguish small differences in wear tate presents formidable problems to those who are developing new materials and surface treatments. Methods for measuring wear in ASTM standard test methods are discussed. Errors in using alterate methods of wear measurement on the same test specimen are also described. Human judgemental factors are a concern in common methods for wear measurement, and an experiment involving measurement of a wear scar by ten different people is described. Precision in wear measurement is limited both by the capabilities of the measuring instruments and by the nonuniformity of the wear process. A method of measuring wear using nano-scale indentations is discussed. Current and future prospects for incorporating advanced, higher-precision wear measurement methods into standards are considered.

  18. Consideration of Wear Rates at High Velocities

    Science.gov (United States)

    2010-03-01

    tionally, the texts by Bayer [3; 4], Rabinowicz [30], and Stachowiak [32] thoroughly cover the topic of wear mechanisms. A summary of the material is...March 1976. 30. Rabinowicz , E. Friction and Wear of Metals. John Wiley & Sons, New York, 1995. 31. Saka, N., A. M. Eleiche, and N. P. Suh. “Wear of

  19. An Evaluation of High Velocity Wear

    Science.gov (United States)

    2007-03-01

    x10F~ -4 [18:18-19]. Authors such as Hutchings and Rabinowicz however, do not explicitly limit equation (12) to plastic wear. They suggest that...Surface Melting of Rotating Bands. Wear, Vol. 38, 235- 243 21. Rabinowicz , E. (1965). Friction and Wear of Materials (Second ed.). New York, NY

  20. Sliding wear resistance of iron aluminides

    Indian Academy of Sciences (India)

    Garima Sharma; M Sundararaman; N Prabhu; G L Goswami

    2003-04-01

    Room temperature dry sliding wear behaviour of iron aluminides containing 28% aluminium and various amounts of chromium has been investigated using pin on disk wear tester. The aluminides were heat treated to have ordered 3 structure. It was found that wear rate of the aluminides increased with the increase of applied normal load and sliding speed. Wear resistance of the aluminides increased with increase in chromium content. SEM observation of the worn surface showed that the microcutting and microploughing were the dominant sliding wear mechanisms.

  1. Wear prediction in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, E.J. [USDOE Morgantown Energy Technology Center, WV (United States); Rogers, W.A. [EG and G Washington Analytical Services Center, Inc., Morgantown, WV (United States)

    1993-06-01

    A procedure to model the wear of surfaces exposed to a fluidized bed is formulated. A stochastic methodology adapting the kinetic theory of gases to granular flows is used to develop an impact wear model. This uses a single-particle wear model to account for impact wear from all possible-particle collisions. An adaptation of a single-particle abrasion model to describe the effects of many abrading particles is used to account for abrasive wear. Parameters describing granular flow within the fluidized bed, necessary for evaluation of the wear expressions, are determined by numerical solution of the fluidized bed hydrodynamic equations. Additional parameters, describing the contact between fluidized particles and the wearing surface, are determined by optimization based on wear measurements. The modeling procedure was used to analyze several bubbling and turbulent fluidized bed experiments with single-tube and tube bundle configurations. Quantitative agreement between the measured and predicted wear rates was found, with some exceptions for local wear predictions. This work demonstrates a methodology for wear predictions in fluidized beds.

  2. Fluoridation and tooth wear in Irish adults.

    LENUS (Irish Health Repository)

    Burke, F M

    2010-10-01

    The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

  3. Wear of micro end mills

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2005-01-01

    This paper addresses the important issue of wear on micro end mills considering relevant metrological tools for its characterization and quantification. Investigation of wear on micro end mills is particularly difficult and no data are available in the literature. Small worn volumes cause large...... deviations from the ideal micro tool shape, dramatically changing the cutting edge profile as well as rake and clearance angles. This critically affects the performance of the micro tool leading to increased cutting forces and micro tool deflections with detrimental effects on the accuracy of the machined...... part. For this investigation 200 microns end mills are considered. Visual inspection of the micro tools requires high magnification and depth of focus. 3D reconstruction based on scanning electron microscope (SEM) images and stereo-pair technique is foreseen as a possible method for quantification...

  4. Hydraulic System Wear Debris Analysis.

    Science.gov (United States)

    1982-08-03

    drawn. Each one-=L sample was drawn with a clean plastic pipette of one-mL capacity. The samples were placed in clean Ferrogram preparation bottles ...and from cavities in a block which held linear seals into sampling bottles . Several photographs of this debris , which was deposited on Ferro- grams...silicon in the glass overshadowed the elements of the wear debris . To overcome this difficulty, the Ferrogram should be pre- pared on a carbon-filled

  5. Wear mechanism and wear prevention in coal-fueled diesel engines. Task 3, Traditional approaches to wear prevention

    Energy Technology Data Exchange (ETDEWEB)

    Schwalb, J.A.

    1991-06-01

    Contamination of the lube-oil with hard abrasive particles leads to a three-body abrasive wear mechanism that highly accelerates piston ring/cylinder liner wear in coal-fueled diesel engines. One approach to reducing that wear is to modify the size and orientation of surface asperities on the cylinder to enhance the formation of a hydrodynamic film, and to provide avenues of escape for particles that would otherwise be trapped in the wear zone. Another approach is to introduce additives into the contaminated lube-oil that further enhance hydrodynamic film formation, form chemical films on the wearing surfaces, or form films on the contaminant particles. This work focuses on defining the effects of cylinder liner surface finish, various configurations of slots in the cylinder liner surface, and various additives in the contaminated lube-oil on the wear process. Wear tests were initiated in a bench apparatus using coal-ash contaminated lube-oil to test the various wear configurations. The results of these tests indicate that the formation of a hydrodynamic film between the ring and cylinder specimens is enhanced by increasing surface roughness, and by orienting the surface asperities normal to the direction of ring travel but modifications to the cylinder liner surface did not greatly reduce the wear rate. Additives to the lubricant seemed to have a much more significant effect on wear, with a dispersant additive highly accelerating the wear, while a detergent additive was able to reduce the wear almost to the rate achieved where there was no contaminant.

  6. A new methodology for predictive tool wear

    Science.gov (United States)

    Kim, Won-Sik

    An empirical approach to tool wear, which requires a series of machining tests for each combination of insert and work material, has been a standard practice for industries since early part of the twentieth century. With many varieties of inserts and work materials available for machining, the empirical approach is too experiment-intensive that the demand for the development of a model-based approach is increasing. With a model-based approach, the developed wear equation can be extended without additional machining experiments. The main idea is that the temperatures on the primary wear areas are increasing such that the physical properties of the tool material degrade substantially and consequently tool wear increases. Dissolution and abrasion are identified to be the main mechanisms for tool wear. Flank wear is predominantly a phenomenon of abrasion as evident by the presence of a scoring mark on the flank surface. Based on this statement, it is reasonable to expect that the flank-wear rate would increase with the content of hard inclusions. However, experimental flank wear results did not necessary correspond to the content of cementite phase present in the steels. Hence, other phenomena are believed to significantly affect wear behavior under certain conditions. When the cutting temperature in the flank interface is subjected to high enough temperatures, pearlitic structure austenizes. During the formation of a new austenitic phase, the existing carbon is dissolved into the ferrite matrix, which will reduce the abrasive action. To verify the austenitic transformation, turning tests were conducted with plain carbon steels. The machined surface areas are imaged using X-ray diffraction the Scanning Electron Microscope (SEM) and the Transmission Electron Microscope (TEM). On the other hand, crater wear occurs as a result of dissolution wear and abrasive wear. To verify the wear mechanisms of crater wear, various coating inserts as well as uncoated inserts were

  7. Surface Wear Measurement Using Optical Correlation Technique

    Science.gov (United States)

    Acinger, Kresimir

    1983-12-01

    The coherent optical correlation technique was applied for measuring the surface wear of a tappet (part of car engine), worn by friction with the camshaft. It was found that maximum correlation intensity decays exponentially with the number of wear cycles (i.e. camshaft revolutions). Tappets of the same make have an identical rate of correlation decay. Tappets of different makes have different rates of correlation decay which are in agreement with observed long term wear.

  8. Wear of hard materials by hard particles

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.

    2003-10-01

    Hard materials, such as WC-Co, boron carbide, titanium diboride and composite carbide made up of Mo2C and WC, have been tested in abrasion and erosion conditions. These hard materials showed negligible wear in abrasion against SiC particles and erosion using Al2O3 particles. The WC-Co materials have the highest wear rate of these hard materials and a very different material removal mechanism. Wear mechanisms for these materials were different for each material with the overall wear rate controlled by binder composition and content and material grain size.

  9. Abrasive Wear Map of Polymer Tapes in Sand Dust Environment

    Institute of Scientific and Technical Information of China (English)

    WU Tong-hai; DIAO Dong-feng

    2006-01-01

    To make clear the wear conditions of ATM (Automatic Teller Machine) tribosystem when servicing in Chinese sand dust environment, abrasive wear of two kinds of polymer tapes specified for ATM, PI (Polyimide) and PEN (Polyethylene-2, 6-naphthalenedicarboxylate), was investigated in simulated sand dust environment with ATM tape-scraper tribosystem under various conditions of loads and sliding distances. The surface profiles of worn tape were measured with a surface profiler in order to calculating the wear cross-section areas and the wear volumes. The specific wear rates of polymer tapes were calculated under load conditions of 0.6, 1 and 1.5 N, and wear mechanisms were investigated with optical topography photos. As main results, the specific wear rates show stage variations in the wear process and the wear resistance of polymer tape shows good relationship with the mechanical deformation factors. In consideration of the service life, four wear models are generalized according to the magnitude of specific wear rates,which include no wear, mild wear, normal wear and severe wear model and the corresponding wear mechanisms for the four wear models are discussed with typical worn topographies. Based on the wear models and corresponding wear mechanisms, the abrasive wear maps of two polymer tapes servicing in sand dust environments are concluded for its industrial applications.

  10. Enamel wear opposing polished and aged zirconia.

    Science.gov (United States)

    Burgess, J O; Janyavula, S; Lawson, N C; Lucas, T J; Cakir, D

    2014-01-01

    Aging of dental zirconia roughens its surface through low temperature degradation. We hypothesized that age-related roughening of zirconia crowns may cause detrimental wear to the enamel of an opposing tooth. To test our hypothesis, we subjected artificially aged zirconia and reference specimens to simulated mastication in a wear device and measured the wear of an opposing enamel cusp. Additionally, the roughness of the pretest surfaces was measured. The zirconia specimens, artificially aged by autoclave, showed no significant increase in roughness compared to the nonaged specimens. Furthermore, no significant difference in material or opposing enamel wear between the aged and nonaged zirconia was seen. All zirconia specimens showed less material and opposing enamel wear than the enamel to enamel control or veneering porcelain specimens. Scanning electron micrographs showed relatively smooth surfaces of aged and nonaged zirconia following wear testing. The micrographs of the veneering ceramic showed sharp fractured edges and fragments of wear debris. Zirconia may be considered a wear-friendly material for restorations opposing enamel, even after simulated aging.

  11. Numerical prediction of car tire wear

    NARCIS (Netherlands)

    Lupker, H.A.; Cheli, F.; Braghin, F.; Gelosa, E.; Keckman, A.

    2004-01-01

    Due to their many economic and ecological implications, the possibility to predict tire wear is of major importance to tire manufacturers, fleet owners and governments. Based on these observations, in 2000, a three-year project named TROWS (Tire and Road Wear and Slip assessment was started. One of

  12. Concrete ice abrasion rig and wear measurements

    NARCIS (Netherlands)

    Shamsutdinova, G.; Rike, P.B.; Hendriks, M.A.N.; Jacobsen, S.

    2015-01-01

    The wear of concrete material due to ice movement is a challenge for offshore and coastal structures. Concrete surfaces exposed to moving ice are subjected to wear at various rates depending on concrete and ice properties. At NTNU, Department of Structural Engineering, concrete ice abrasion phenomen

  13. Wear and microstructure in fine ceramic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Vijande-Diaz, R.; Belzunce, J.; Fernandez, E. (ETS de Ingenieros Industriales, Area de Ingeneria Mecanica, Gijon (Spain)); Rincon, A.; Perez, M.C. (Inst. de Fisica-Quimica ' Roco Solano' , CSIC, Madrid (Spain))

    1991-08-15

    This paper presents a study of the wear resistance of two ceramic, plasma sprayed coatings of Al{sub 2}O{sub 3} and Cr{sub 2}O{sub 3}. Tests were carried out using an LWF-1 standard machine, with lineal contact, under dry friction, abrasion and lubricant conditions. The purpose of the tests were to study how load and speed affect material wear. Results show the lower wear rate of the ceramic coating compared with the steel one, as well as how remarkably load affects wear. On the other hand, however, considering the speed ranges used, wear resistance does not depend significantly on speed. The paper proves that the wear process follows Czichos' law. At the same time, reformulation of Archard's equation allows us to quantify wear using easily measurable factors such as pressure, speed, hardness, and those factors typically featuring this type of coatings, e.g. porosity. Also, a micrographic study of the coatings carried out by means of a scanning electron microscope has evidenced three stages in the wear mechanism: (a) plastic deformation of particles; (b) crack nucleation and propagation; and (c) loosening of ceramic particles. (orig.).

  14. Contact lens wear is intrinsically inflammatory.

    Science.gov (United States)

    Efron, Nathan

    2017-01-01

    Eye-care practitioners typically associate ocular inflammation during contact lens wear with serious complications such as microbial keratitis; however, more subtle mechanisms may be at play. This paper tests the notion that contact lens wear is intrinsically inflammatory by exploring whether uncomplicated contact lens wear meets the classical, clinical definition of inflammation - rubor (redness), calor (heat), tumor (swelling), dolor (pain) and functio laesa (loss of function) - as well as the contemporary, sub-clinical definition of inflammation (cellular and biochemical reactions). It is demonstrated that all of these clinical and sub-clinical criteria are met with hydrogel lens wear and most are met with silicone hydrogel lens wear, indicating that uncomplicated contact lens wear is intrinsically inflammatory. Consideration of both traditional and contemporary thinking about the role of inflammation in the human body leads to the perhaps surprising conclusion that the chronic, low grade, sub-clinical inflammatory status of the anterior eye during contact lens wear, which may be termed 'para-inflammation', is a positive, protective phenomenon, whereby up-regulation of the immune system, in a non-damaging way, maintains the eye in a state of 'heightened alert', ready to ward off any extrinsic noxious challenge. Characterisation of this inflammatory status may lead to the development of lens engineering or pharmacological strategies to modulate contact lens-induced inflammation, so as to render lens wear more safe and comfortable. © 2016 Optometry Australia.

  15. Inhibition of erosive wear by fluoride varnish

    NARCIS (Netherlands)

    Vieira, A.; Jager, D. H. J.; Ruben, J. L.; Huysmans, M. C. D. N. J. M.

    2007-01-01

    It has been suggested that fluoride products with a protective mechanical component are advantageous in the prevention of erosive wear. The aim of this study was to evaluate in situ the effect of fluoride varnish (FV) in the prevention of wear due to erosion and combined erosion and toothbrush abras

  16. Concrete ice abrasion rig and wear measurements

    NARCIS (Netherlands)

    Shamsutdinova, G.; Rike, P.B.; Hendriks, M.A.N.; Jacobsen, S.

    2015-01-01

    The wear of concrete material due to ice movement is a challenge for offshore and coastal structures. Concrete surfaces exposed to moving ice are subjected to wear at various rates depending on concrete and ice properties. At NTNU, Department of Structural Engineering, concrete ice abrasion phenomen

  17. Friction and Wear Behaviors of Nanostructured Metals

    Institute of Scientific and Technical Information of China (English)

    Zhong HAN; Yusheng ZHANG; Ke LU

    2008-01-01

    Nanostructured (ns) materials, i.e., polycrystalline materials with grain sizes in the nanometer regime (typically below 100 nm), have drawn considerable attention in the past decades due to their unique properties such as high strength and hardness. Wear resistance of ns materials, one of the most important properties for engineering materials, has been extensively investigated in the past decades. Obvious differences have been identified in friction and wear behaviors Between the ns materials and their corresponding coarse-grained (cg) counterparts, consistently correlating with their unique structure characteristics and mechanical properties. On the other hand, the superior tribological properties of ns materials illustrate their potential applications under contact loads. The present overview will summarize the important progresses achieved on friction and wear behaviors of ns metallic materials, including ultrafine-grained (ufg) materials in recent years. Tribological properties and effects on friction and wear behaviors of ns materials will be discussed under different wear conditions including abrasive wear, sliding wear, and fretting wear. Their correlations with mechanical properties will be analyzed. Perspectives on development of this field will be highlighted as well.

  18. Inhibition of erosive wear by fluoride varnish

    NARCIS (Netherlands)

    Vieira, A.; Jager, D. H. J.; Ruben, J. L.; Huysmans, M. C. D. N. J. M.

    2007-01-01

    It has been suggested that fluoride products with a protective mechanical component are advantageous in the prevention of erosive wear. The aim of this study was to evaluate in situ the effect of fluoride varnish (FV) in the prevention of wear due to erosion and combined erosion and toothbrush

  19. Fault Wear and Friction Evolution: Experimental Analysis

    Science.gov (United States)

    Boneh, Y.; Chang, J. C.; Lockner, D. A.; Reches, Z.

    2011-12-01

    Wear is an inevitable product of frictional sliding of brittle rocks as evidenced by the ubiquitous occurrence of fault gouge and slickenside striations. We present here experimental observations designed to demonstrate the relationship between wear and friction and their governing mechanisms. The experiments were conducted with a rotary shear apparatus on solid, ring-shaped rock samples that slipped for displacements up to tens of meters. Stresses, wear and temperature were continuously monitored. We analyzed 86 experiments of Kasota dolomite, Sierra White granite, Pennsylvania quartzite, Karoo gabbro, and Tennessee sandstone at slip velocities ranging from 0.002 to 0.97 m/s, and normal stress from 0.25 to 6.9 MPa. We conducted two types of runs: short slip experiments (slip distance mechanisms; and long slip experiments (slip distance > 3 m) designed to achieve mature wear conditions and to observe the evolution of wear and friction as the fault surfaces evolved. The experiments reveal three wear stages: initial, running-in, and steady-state. The initial stage is characterized by (1) discrete damage striations, the length of which is comparable to total slip , and local pits or plow features; (2) timing and magnitude of fault-normal dilation corresponds to transient changes of normal and shear stresses; and (3) surface roughness increasing with the applied normal stress. We interpret these observations as wear mechanisms of (a) plowing into the fresh rock surfaces; (b) asperity breakage; and (c) asperity climb. The running-in stage is characterized by (1) intense wear-rate over a critical wear distance of Rd = 0.3-2 m; (2) drop of friction coefficient over a weakening distance of Dc = 0.2-4 m; (3) Rd and Dc display positive, quasi-linear relation with each other. We interpret these observations as indicating the organizing of newly-created wear particles into a 'three-body' structure that acts to lubricate the fault (Reches & Lockner, 2010). The steady

  20. Biologically Based Restorative Management of Tooth Wear

    Directory of Open Access Journals (Sweden)

    Martin G. D. Kelleher

    2012-01-01

    Full Text Available The prevalence and severity of tooth wear is increasing in industrialised nations. Yet, there is no high-level evidence to support or refute any therapeutic intervention. In the absence of such evidence, many currently prevailing management strategies for tooth wear may be failing in their duty of care to first and foremost improve the oral health of patients with this disease. This paper promotes biologically sound approaches to the management of tooth wear on the basis of current best evidence of the aetiology and clinical features of this disease. The relative risks and benefits of the varying approaches to managing tooth wear are discussed with reference to long-term follow-up studies. Using reference to ethical standards such as “The Daughter Test”, this paper presents case reports of patients with moderate-to-severe levels of tooth wear managed in line with these biologically sound principles.

  1. Wear simulation effects on overdenture stud attachments.

    Science.gov (United States)

    Rutkunas, Vygandas; Mizutani, Hiroshi; Takahashi, Hidekazu; Iwasaki, Naohiko

    2011-01-01

    The aim of this study was to evaluate wear effects on overdenture resilient attachments. Six commercially available attachments were investigated: ERA orange and white (EO and EW), Locator pink, white and blue (LRP, LRW and LRB) and OP anchor (OP). Five specimens were used for wear simulation while other two specimens served as controls. Fifteen thousands insertion-removal cycles were simulated. Dimensional changes and surface characteristics were evaluated using light microscopy and SEM, respectively. Sudden decrease of retentive force was characteristic for EO and EW attachments. Retentive force of Locator attachments fluctuated throughout the wear simulation period. Dimensional changes and surface wear was more expressed on plastic cores than on plastic rings of attachment males. Based on SEM analysis, some of the specimens obtained smoother surface after wear simulation. Mechanism of retention loss of resilient overdenture attachments can be only partially explained by dimensional changes and surface alterations.

  2. Modeling wear of cast Ti alloys.

    Science.gov (United States)

    Chan, Kwai S; Koike, Marie; Okabe, Toru

    2007-05-01

    The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

  3. Assessment of variations in wear test methodology.

    Science.gov (United States)

    Gouvêa, Cresus V D; Weig, Karin; Filho, Thales R M; Barros, Renata N

    2010-01-01

    The properties of composite resin for dental fillings were improved by development, but its weakness continues to be its wear strength. Several tests have been proposed to evaluate wear in composite resin materials. The aim of this study was to verify how polishing and the type of abrasive can influence the wear rate of composite resin. The test was carried out on two groups. In one group we employed an ormocer and a hybrid composite that was polished group the composite was polished with the same abrasive paper plus a 1 microm and 0.25 microm grit diamond paste. A three-body wear test was performed using the metal sphere of the wear test machine, the composite and an abrasive. A diamond paste and aluminum oxide dispersion were used as abrasive. Analysis of the results showed that there was no difference between polishing techniques, but revealed a difference between abrasives.

  4. Dynamic SEM wear studies of tungsten carbide cermets. [friction and wear experiments

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined, and etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the tungsten carbide (WC) and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation, and the wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation, and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

  5. Asphalt wear and pollution transport

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, Asa [Division of Traffic Engineering, Lulea University of Technology Lulea (Sweden)

    1996-09-06

    Studded tires cause extensive wear of road surfaces during winter producing small particles. Besides transporting different adsorbed pollutants these particles also discharge metal ions by their own natural content. The major part (95%) of the asphalt is composed of stone fractions. The rest consists mainly of bitumen, which contains trace quantities of metals. Laboratory studies in this study have demonstrated different adsorbing properties of metal ions, as well as differences in adsorption when comparing stone materials. Two stone materials, a gabbro and a porphyry, have been tested for their adsorption properties concerning Pb, Cu, Zn and Cd. The gabbro showed better adsorption capacity than the porphyry. Gabbro has coarser grains, it is softer, and also has a higher content of most metals compared to the porphyry. In all tests lead and copper are more adsorbed than zinc and cadmium. All metal ions are released at about the same pH ({approx}4)

  6. Energetic aspects of boring tools wear

    Directory of Open Access Journals (Sweden)

    Lazarová Edita

    2002-03-01

    Full Text Available In the process of rock desintegration a boring tool is subjected to the wear. From a viewpoint of the bit wear, changes on the contact of operating tool with rock at its one-shot and rerun load or overload by external forces are technically significant. Theis change results in the degradation of bit working properties and the output of desintegration also decreases. In the major part of cases, together with the bit wear, the contact area of a tool with a rock massifs enhanced and this fact causes an increase of fines (dust creation during the desintegration. The wear is always connected with a friction, forces action, deformation, damage, and the increased mechanical work consumption. As to energetic aspects of bit wear, the wear was observed as a function of bore length and in the most of cases as a dependence of the operating time. A linear dependence between the wear intensity (bit wear per unit of bore length and the specific energy of desintegration (energy consumed per volume unit of desintegrated rock was experimentally verified. Thus, the changes of bit wear can be implicitly observed by monitoring the specific energy. At the same time, the specific energy is a function of input parameters of the desintegration process and in the field of applicable external forces it shows an extreme (minimum. Therefore, the specific energy is useful for the extreme optimisation of the rock desintegration process from the viewpoint of the bit wear. It was mathematically proven that the tool output at the desintegration exponentially decreases with the amount of work consumed in the rock desintegration. The derivation of this knowledge comes out from the Krendelev equation.

  7. Adhesive Wear of Rollers in Vacuum

    Science.gov (United States)

    Shaeef, Iqbal; Krantz, Timothy L.

    2012-01-01

    This work was done to support NASA's James Webb Space Telescope that is equipped with a Near Infrared Camera and Spectrograph and Micro Shutter Assembly (MSA). A MSA mechanism's qualification test in cryogenic vacuum at 30deg K for 96K cycles resulted in roller wear and formation of some debris. Lab tests in vacuum were conducted at NASA Glenn Research Center (GRC) to understand the wear of Ti6Al4V mated with 440F steel rollers. Misalignment angle was found to have the most significant effect on debris formation. At misalignment angle of 1.4deg, significant amount of wear debris were formed within 50,000 cycles. Very few wear particles were found for a zero misalignment angle, and the total wear was small even after 367,000 cycles. The mode of wear in all the tests was attributed to adhesion, which was clearly evident from video records as well as the plate-like amalgamated debris material from both rollers. The adhesive wear rate was found to be approximately proportional to the misalignment angle. The wear is a two-way phenomenon, and the mixing of both roller materials in wear debris was confirmed by x-ray fluorescence (XRF) and EDX spectra. While there was a net loss of mass from the steel rollers, XRF and energy dispersive x-ray (EDX) spectra showed peaks of Ti on steel rollers, and peaks of Fe on Ti rollers. These results are useful for designers in terms of maintaining appropriate tolerances to avoid misalignment of rolling elements and the resulting severe wear

  8. Wear Characteristics of Metallic Biomaterials: A Review

    Directory of Open Access Journals (Sweden)

    Mohamed A. Hussein

    2015-05-01

    Full Text Available Metals are extensively used in a variety of applications in the medical field for internal support and biological tissue replacements, such as joint replacements, dental roots, orthopedic fixation, and stents. The metals and alloys that are primarily used in biomedical applications are stainless steels, Co alloys, and Ti alloys. The service period of a metallic biomaterial is determined by its abrasion and wear resistance. A reduction in the wear resistance of the implant results in the release of incompatible metal ions into the body that loosen the implant. In addition, several reactions may occur because of the deposition of wear debris in tissue. Therefore, developing biomaterials with high wear resistance is critical to ensuring a long life for the biomaterial. The aim of this work is to review the current state of knowledge of the wear of metallic biomaterials and how wear is affected by the material properties and conditions in terms of the type of alloys developed and fabrication processes. We also present a brief evaluation of various experimental test techniques and wear characterization techniques that are used to determine the tribological performance of metallic biomaterials.

  9. Wear mechanism and wear prevention in coal-fueled diesel engines. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schwalb, J.A.; Ryan, T.W.

    1991-10-01

    Coal fueled diesel engines present unique wear problems in the piston ring/cylinder liner area because of their tendency to contaminate the lube-oil with high concentrations of highly abrasive particles. This program involved a series of bench-scale wear tests and engine tests designed to investigate various aspects of the ring/liner wear problem and to make specific recommendations to engine manufacturers as to how to alleviate these problems. The program was organized into tasks, designed to accomplish the following objectives: (1) define the predominant wear mechanisms causing accelerated wear in the ring/liner area; (2) investigate the effectiveness of traditional approaches to wear prevention to prevent wear in coal-fueled engines; (3) further refine information on the most promising approaches to wear prevention; (4) present detailed information and recommendations to engine manufacturers on the most promising approach to wear prevention; (5) present a final report covering the entire program; (6)complete engine tests with a coal-derived liquid fuel, and investigate the effects of the fuel on engine wear and emissions.

  10. Wear mechanism and wear prevention in coal-fueled diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Schwalb, J.A.; Ryan, T.W.

    1991-10-01

    Coal fueled diesel engines present unique wear problems in the piston ring/cylinder liner area because of their tendency to contaminate the lube-oil with high concentrations of highly abrasive particles. This program involved a series of bench-scale wear tests and engine tests designed to investigate various aspects of the ring/liner wear problem and to make specific recommendations to engine manufacturers as to how to alleviate these problems. The program was organized into tasks, designed to accomplish the following objectives: (1) define the predominant wear mechanisms causing accelerated wear in the ring/liner area; (2) investigate the effectiveness of traditional approaches to wear prevention to prevent wear in coal-fueled engines; (3) further refine information on the most promising approaches to wear prevention; (4) present detailed information and recommendations to engine manufacturers on the most promising approach to wear prevention; (5) present a final report covering the entire program; (6)complete engine tests with a coal-derived liquid fuel, and investigate the effects of the fuel on engine wear and emissions.

  11. Dimensional Description of On-line Wear Debris Images for Wear Characterization

    Institute of Scientific and Technical Information of China (English)

    WU Tonghai; PENG Yeping; DU Ying; WANG Junqun

    2014-01-01

    As one of the most wear monitoring indicator, dimensional feature of individual particles has been studied mostly focusing on off-line analytical ferrograph. Recent development in on-line wear monitoring with wear debris images shows that merely wear debris concentration has been extracted from on-line ferrograph images. It remains a bottleneck of obtaining the dimension of on-line particles due to the low resolution, high contamination and particle’s chain pattern of an on-line image sample. In this work, statistical dimension of wear debris in on-line ferrograph images is investigated. A two-step procedure is proposed as follows. First, an on-line ferrograph image is decomposed into four component images with different frequencies. By doing this, the size of each component image is reduced by one fourth, which will increase the efficiency of subsequent processing. The low-frequency image is used for extracting the area of wear debris, and the high-frequency image is adopted for extracting contour. Second, a statistical equivalent circle dimension is constructed by equaling the overall wear debris in the image into equivalent circles referring to the extracted total area and premeter of overall wear debris. The equivalent circle dimension, reflecting the statistical dimension of larger wear debris in an on-line image, is verified by manual measurement. Consequently, two preliminary applications are carried out in gasoline engine bench tests of durability and running-in. Evidently, the equivalent circle dimension, together with the previously developed concentration index, index of particle coverage area (IPCA), show good performances in characterizing engine wear conditions. The proposed dimensional indicator provides a new statistical feature of on-line wear particles for on-line wear monitoring. The new dimensional feature conveys profound information about wear severity.

  12. Prediction of Wear in Crosslinked Polyethylene Unicompartmental Knee Arthroplasty

    Directory of Open Access Journals (Sweden)

    Jonathan Netter

    2015-05-01

    Full Text Available Wear-related complications remain a major issue after unicompartmental arthroplasty. We used a computational model to predict knee wear generated in vitro under diverse conditions. Inverse finite element analysis of 2 different total knee arthroplasty designs was used to determine wear factors of standard and highly crosslinked polyethylene by matching predicted wear rates to measured wear rates. The computed wear factor was used to predict wear in unicompartmental components. The articular surface design and kinematic conditions of the unicompartmental and tricompartmental designs were different. Predicted wear rate (1.77 mg/million cycles was very close to experimental wear rate (1.84 mg/million cycles after testing in an AMTI knee wear simulator. Finite element analysis can predict experimental wear and may reduce the cost and time of preclinical testing.

  13. Prediction of wear rates in comminution equipment

    DEFF Research Database (Denmark)

    Jensen, Lucas Roald Dörig; Fundal, Erling; Møller, Per

    2010-01-01

    Raw material comminution equipment may be exposed to excessive wear, which makes it difficult to operate minerals processing plants continuously because lengthy and unplanned shut-downs interrupt the overall process. In general, most comminution equipment is fine-tuned to operate at low vibrations......-resistant high chromium white cast iron (21988/JN/HBW555XCr21), a heat-treated wear resistant steel (Hardox 400) and a plain carbon construction steel (S235). Quartz, which accounts for the largest wear loss in the cement industry, was chosen as abrasive. Other process parameters such as velocity (1–7 m...

  14. The predictive analysis of wear work-rates in wear test rigs

    Energy Technology Data Exchange (ETDEWEB)

    Phalippou, C.; Delaune, X.

    1996-12-31

    Impact and sliding wear in components is classically studied, as far as the wear laws are concerned, in specific wear test rigs that simulate the vibratory motion induced by the flow. In this paper, an experimental and numerical study on the impact forces and wear work-rates of a typical AECL rig is presented. The mode shapes and frequencies are measured and compared with finite element computations. Impact and sliding motions between the wear specimens are calculated and compared to the experimental results. Impact forces, mean values of wear work-rates as well as the specimen relative motions are found to be close to the experimental data. (authors). 14 refs., 9 figs., 5 tabs.

  15. Wear mechanism and wear prevention in coal-fueled diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Schwalb, J.A.

    1991-06-01

    Contamination of the lube-oil with hard abrasive particles leads to a three-body abrasive wear mechanism that highly accelerates piston ring/cylinder liner wear in coal-fueled diesel engines. One approach to reducing that wear is to modify the size and orientation of surface asperities on the cylinder to enhance the formation of a hydrodynamic film, and to provide avenues of escape for particles that would otherwise be trapped in the wear zone. Another approach is to introduce additives into the contaminated lube-oil that further enhance hydrodynamic film formation, form chemical films on the wearing surfaces, or form films on the contaminant particles. This work focuses on defining the effects of cylinder liner surface finish, various configurations of slots in the cylinder liner surface, and various additives in the contaminated lube-oil on the wear process. Wear tests were initiated in a bench apparatus using coal-ash contaminated lube-oil to test the various wear configurations. The results of these tests indicate that the formation of a hydrodynamic film between the ring and cylinder specimens is enhanced by increasing surface roughness, and by orienting the surface asperities normal to the direction of ring travel but modifications to the cylinder liner surface did not greatly reduce the wear rate. Additives to the lubricant seemed to have a much more significant effect on wear, with a dispersant additive highly accelerating the wear, while a detergent additive was able to reduce the wear almost to the rate achieved where there was no contaminant.

  16. STUDIES ON TOOL WEAR CONDITION MONITORING

    Directory of Open Access Journals (Sweden)

    Hüseyin Metin ERTUNÇ

    2001-01-01

    Full Text Available In this study, wear mechanisms on cutting tools, especially for the drill bits, during the cutting operation have been investigated. As the importance of full automation in industry has gained substantial importance, tool wear condition monitoring during the cutting operation has been the subject of many investigators. Tool condition monitoring is very crucial in order to change the tool before breakage. Because tool breakage can cause considerable economical damage to both the machine tool and workpiece. In this paper, the studies on the monitoring of drill bit wear in literature have been introduced; the direct/indirect techniques used and sensor fusion techniques have been summarized. The methods which were proposed to determine tool wear evolution as processing the sensor signals collected have been provided and their references have been given for detailed information.

  17. Wear behavior of austenite containing plate steels

    Science.gov (United States)

    Hensley, Christina E.

    As a follow up to Wolfram's Master of Science thesis, samples from the prior work were further investigated. Samples from four steel alloys were selected for investigation, namely AR400F, 9260, Hadfield, and 301 Stainless steels. AR400F is martensitic while the Hadfield and 301 stainless steels are austenitic. The 9260 exhibited a variety of hardness levels and retained austenite contents, achieved by heat treatments, including quench and tempering (Q&T) and quench and partitioning (Q&P). Samples worn by three wear tests, namely Dry Sand/Rubber Wheel (DSRW), impeller tumbler impact abrasion, and Bond abrasion, were examined by optical profilometry. The wear behaviors observed in topography maps were compared to the same in scanning electron microscopy micrographs and both were used to characterize the wear surfaces. Optical profilometry showed that the scratching abrasion present on the wear surface transitioned to gouging abrasion as impact conditions increased (i.e. from DSRW to impeller to Bond abrasion). Optical profilometry roughness measurements were also compared to sample hardness as well as normalized volume loss (NVL) results for each of the three wear tests. The steels displayed a relationship between roughness measurements and observed wear rates for all three categories of wear testing. Nanoindentation was used to investigate local hardness changes adjacent to the wear surface. DSRW samples generally did not exhibit significant work hardening. The austenitic materials exhibited significant hardening under the high impact conditions of the Bond abrasion wear test. Hardening in the Q&P materials was less pronounced. The Q&T microstructures also demonstrated some hardening. Scratch testing was performed on samples at three different loads, as a more systematic approach to determining the scratching abrasion behavior. Wear rates and scratch hardness were calculated from scratch testing results. Certain similarities between wear behavior in scratch testing

  18. A Study of Slipper and Rail Wear Interaction at Low Speed

    Science.gov (United States)

    2014-06-19

    taking care of the boys, a house and a dog and for not getting discouraged. I pray that they will learn as I have how important it is to ensure Yahovah...wear, delamination wear, seizure wear, melt wear, severe oxidational wear and adhesive wear. Adhesive wear comprised of three zones: low speed...model is experiencing seizure or melt wear, then something is wrong with the model. Lim and Ashby also published on their wear map the normalized wear

  19. Third abrasive wear mode: is it possible?

    Directory of Open Access Journals (Sweden)

    Ronaldo Câmara Cozza

    2014-04-01

    Full Text Available The objective of this paper is to propose an initial discussion on the characterization of a third abrasive wear mode. The results obtained in a previous work [1] under different test conditions revealed the occurrence of the superposition of the “rolling” and “grooving” abrasive wear modes. This phenomenon was denoted “micro-rolling abrasion” due to the observation that “rolling abrasion” was found to act on “grooving abrasion”.

  20. Biotribology :articular cartilage friction, wear, and lubrication

    OpenAIRE

    Schroeder, Matthew O

    1995-01-01

    This study developed, explored, and refined techniques for the in vitro study of cartilage-on-cartilage friction, deformation, and wear. Preliminary results of in vitro cartilage-on- cartilage experiments with emphasis on wear and biochemistry are presented. Cartilage-bone specimens were obtained from the stifle joints of steers from a separate controlled study. The load, sliding speed, and traverse of the lower specimens were held constant as lubricant and test length were varied. Lubric...

  1. Pseudomembranous candidiasis in patient wearing full denture

    Directory of Open Access Journals (Sweden)

    Nurdiana Nurdiana

    2009-06-01

    Full Text Available Background: Oral candidiasis is a common opportunistic infection of the oral cavity caused by an overgrowth of Candida species, the commonest being Candida albicans. Candida albicans is a harmless commensal organism inhabiting the mouths but it can change into pathogen and invade tissue and cause acute and chronic disease. Dentures predispose to infection with Candida in as many as 65% of elderly people wearing full upper dentures. Purpose: The purpose of this case report is to discuss thrush in patient wearing full denture which rapidly developed. Case: This paper report a case of 57 year-old man who came to the Oral Medicine Clinic Faculty of Dentistry Airlangga University with clinical appearance of pseudomembranous candidiasis (thrush. Case Management: Diagnosis of this case is confirmed with microbiology examination. Patient was wearing full upper dentures, and from anamnesis known that patient wearing denture for 24 hours and he had poor oral hygiene. Patient was treated with topical (nystatin oral suspension and miconazole oral gel and systemic (ketoconazole antifungal. Patient also instructed not to wear his denture and cleaned white pseudomembrane on his mouth with soft toothbrush. Conclusion: Denture, habit of wearing denture for 24 hours, and poor oral hygiene are predisposing factors of thrush and it can healed completely after treated with topical and systemic antifungal.

  2. Wear Property of Cast Steel Wheel Material in Rail Truck

    Institute of Scientific and Technical Information of China (English)

    MI Guo-fa; LIU Yan-lei; ZHANG Bin; FU Xiu-qin; ZHANG Hong; SONG Guo-xiang

    2009-01-01

    Wear property of material plays a key role in the service time of workpiece.A major objective in the development of new wheel materials is to improve the wear performance.The wear property of B and B+ grade cast steel materials was reported.The results showed that B+ grade cast steel material exhibited better wear property than the B grade material.Carbon content related to the hardness match was the principal factor affecting the wear properties.

  3. Wear-resistance of Aluminum Matrix Microcomposite Materials

    Directory of Open Access Journals (Sweden)

    M. Kandeva

    2011-03-01

    Full Text Available A procedure is developed for the study of wear of aluminum alloys AlSi7 obtained by casting, reinforced by TiC microparticles, before and after heat treatment. Tribological study is realized under conditions of friction on counterbody with fixed abrasive. Experimental results were obtained for mass wear, wear rate, wear intensity and wear-resistance of the alloys with different wt% of microparticles.

  4. Microstructure-Wear Resistance Correlation and Wear Mechanisms of Spark Plasma Sintered Cu-Pb Nanocomposites

    Science.gov (United States)

    Sharma, Amit Siddharth; Biswas, Krishanu; Basu, Bikramjit

    2014-01-01

    The dispersion of a softer phase in a metallic matrix reduces the coefficient of friction (COF), often at the expense of an increased wear rate at the tribological contact. To address this issue, unlubricated fretting wear tests were performed on spark plasma sintered Cu-Pb nanocomposites against bearing steel. The sintering temperature and the Pb content as well as the fretting parameters were judiciously selected and varied to investigate the role of microstructure (grain size, second-phase content) on the wear resistance properties of Cu-Pb nanocomposites. A combination of the lowest wear rate (~1.5 × 10-6 mm3/Nm) and a modest COF (~0.4) was achieved for Cu-15 wt pct Pb nanocomposites. The lower wear rate of Cu-Pb nanocomposites with respect to unreinforced Cu is attributed to high hardness (~2 to 3.5 GPa) of the matrix, Cu2O/Fe2O3-rich oxide layer formation at tribological interface, and exuding of softer Pb particles. The wear properties are discussed in reference to the characteristics of transfer layer on worn surface as well as subsurface damage probed using focused ion beam microscopy. Interestingly, the flash temperature has been found to have insignificant effect on the observed oxidative wear, and alternative mechanisms are proposed. Importantly, the wear resistance properties of the nanocomposites reveal a weak Hall-Petch-like relationship with grain size of nanocrystalline Cu.

  5. REDUCED ENGINE FRICTION AND WEAR

    Energy Technology Data Exchange (ETDEWEB)

    Ron Matthews

    2005-05-01

    This Final Technical Report discusses the progress was made on the experimental and numerical tasks over the duration of this project regarding a new technique for decreasing engine friction and wear via liner rotation. The experimental subtasks involved quantifying the reduction in engine friction for a prototype rotating liner engine relative to a comparable baseline engine. Both engine were single cylinder conversions of nominally identical production four-cylinder engines. Hot motoring tests were conducted initially and revealed that liner rotation decreased engine friction by 20% under motoring conditions. A well-established model was used to estimate that liner rotation should decrease the friction of a four-cylinder engine by 40% under hot motoring conditions. Hot motoring tear-down tests revealed that the crankshaft and valve train frictional losses were essentially the same for the two engines, as expected. However, the rotating liner engine had much lower (>70%) piston assembly friction compared to the conventional engine. Finally, we used the Instantaneous IMEP method to compare the crank-angle resolved piston assembly friction for the two engines. Under hot motoring conditions, these measurements revealed a significant reduction in piston assembly friction, especially in the vicinity of compression TDC when the lubrication regime transitions from hydrodynamic through mixed and into boundary friction. We have some remaining problems with these measurements that we expect to solve during the next few weeks. We will then perform these measurements under firing conditions. We also proposed to improve the state-of-the-art of numerical modeling of piston assembly friction for conventional engines and then to extend this model to rotating liner engines. Our research team first modeled a single ring in the Purdue ring-liner test rig. Our model showed good agreement with the test rig data for a range of speeds and loads. We then modeled a complete piston

  6. Structural transformations in wear resistance of iron- and cobalt-based amorphous alloys during abrasive wear

    Science.gov (United States)

    Korshunov, L. G.; Shabashov, V. A.; Chernenko, N. L.

    2010-04-01

    The wear resistance and structural changes in a number of amorphous alloys based on iron and cobalt and in high-carbon tool steels are studied during wear by a fixed abrasive (crondum, Carborundum) at room temperature and -196°C. The abrasive wear resistance of the amorphous alloys is shown to be 1.6-3.1 lower than that of the high-carbon tool steels having a similar hardness. The relatively low level of the abrasive wear resistance of the amorphous alloys is assumed to be caused by strain softening of their surface during wear. A nanocrystalline structure is found to form in local microvolumes in a thin deformed surface layer of the alloys.

  7. Incisor wear and age in Yellowstone bison

    Science.gov (United States)

    Christianson, D.A.; Gogan, P.J.P.; Podruzny, K.M.; Olexa, E.M.

    2005-01-01

    Biologists commonly use tooth eruption and wear patterns or cementum annuli techniques to estimate age of ungulates. However, in some situations the accuracy or sampling procedures of either approach are undesirable. We investigated the progression of several quantitative measures of wear with age, using permanent first incisors from Yellowstone bison (Bison bison), and tested for differences between sexes and herds. We further investigated the relationship of wear and age to explore an age-estimation method. Labial-lingual width (LLW) correlated best with assigned age (r2=0.66, males; r2=0.76 females). Labial-lingual width differed between sexes, with females showing ∼0.2 mm more wear than males. Additionally, differences in rate of wear existed between bison of the northern and central Yellowstone herds (1.2 and 0.9 mm/year, respectively). We developed a regression formula to test the power of LLW as an estimator of Yellowstone bison age. Our method provided estimated ages within 1 year of the assigned age 73% and 82% of the time for female and male bison, respectively.

  8. Dental Wear: A Scanning Electron Microscope Study

    Directory of Open Access Journals (Sweden)

    Luca Levrini

    2014-01-01

    Full Text Available Dental wear can be differentiated into different types on the basis of morphological and etiological factors. The present research was carried out on twelve extracted human teeth with dental wear (three teeth showing each type of wear: erosion, attrition, abrasion, and abfraction studied by scanning electron microscopy (SEM. The study aimed, through analysis of the macro- and micromorphological features of the lesions (considering the enamel, dentin, enamel prisms, dentinal tubules, and pulp, to clarify the different clinical and diagnostic presentations of dental wear and their possible significance. Our results, which confirm current knowledge, provide a complete overview of the distinctive morphology of each lesion type. It is important to identify the type of dental wear lesion in order to recognize the contributing etiological factors and, consequently, identify other more complex, nondental disorders (such as gastroesophageal reflux, eating disorders. It is clear that each type of lesion has a specific morphology and mechanism, and further clinical studies are needed to clarify the etiological processes, particularly those underlying the onset of abfraction.

  9. Brush seal shaft wear resistant coatings

    Science.gov (United States)

    Howe, Harold

    1995-03-01

    Brush seals suffer from high wear, which reduces their effectiveness. This work sought to reduce brush seal wear by identifying and testing several industry standard coatings. One of the coatings was developed for this work. It was a co-sprayed PSZ with boron-nitride added for a high temperature dry lubricant. Other coatings tested were a PSZ, chrome carbide and a bare rotor. Testing of these coatings included thermal shocking, tensile testing and wear/coefficient of friction testing. Wear testing consisted of applying a coating to a rotor and then running a sample tuft of SiC ceramic fiber against the coating. Surface speeds at point of contact were slightly over 1000 ft/sec. Rotor wear was noted, as well as coefficient of friction data. Results from the testing indicates that the oxide ceramic coatings cannot withstand the given set of conditions. Carbide coatings will not work because of the need for a metallic binder, which oxidizes in the high heat produced by friction. All work indicated a need for a coating that has a lubricant contained within itself and the coating must be resistant to an oxidizing environment.

  10. Impact wear behaviors of Hadfield manganese steel

    Institute of Scientific and Technical Information of China (English)

    FANG Liang; XU Yun-hua; CEN Qi-hong; ZHU Jin-hua

    2005-01-01

    Impact wear behaviors of Hadfield manganese steel at different impact angles were investigated. The results of impact wear tests show that there exists a critical impact load for Hadfield steel. The wear rate suddenly turns down after some impact cycles when the impact load is greater than the critical load. The critical impact load is smaller than 8.2 J in this research because the nano-sized austenitic grains embedded in amorphous delay the crack propagation in subsurface. From high resolution transmission electron microscope (HRTEM) examination of subsurface microstructure, it is found that a large amount of nano-sized grains embedded in bulk amorphous matrix are fully developed and no martensitic transformation occurs during the impact wear process. The analytical results of worn surface morphology and debris indicate that the initiation of crack, propagation and spalling are restricted in the amorphous phase, resulting in the size distribution of debris in nano-sizes, which is the reason why the wear rate of Hadfield steel is greatly decreased at high impact load.

  11. [Wear and different restorative materials--a review].

    Science.gov (United States)

    Beyth, N; Sharon, E; Lipovetsky, M; Smidt, A

    2006-07-01

    Wear of materials is a complex and unpredictable phenomenon. The variables affecting the mechanism of wear include the properties of the two contacting materials and the surrounding and interfacial media. This paper reviews the dental wear of different restorative materials and their counter effect on the tooth structure. It presents the updated classifications for tooth surface lesions termed dental wear, and discusses the wear behavior of various restorative materials. Some guidelines for restorative material selection are given. Clinical wear bears a multifactorial etiology, understanding the mechanism of action is an important step in an appropriate restoration material selection. Each material selected should meet the individual wear behavior and needs. Individual factors may enhance the wear rates: aggressive tooth brushing, parafunctions, diet, acidic/aqueous environment, surface geometry, and diminished tooth support. Supportive treatment following restoration is important to monitor wear rates.

  12. Wear Resistant Amorphous and Nanocomposite Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  13. A View on Wear Mechanism of Metallic Card Clothing

    Institute of Scientific and Technical Information of China (English)

    WU Liang; WANG Wen-qiang; NI Huai-sheng

    2008-01-01

    The wear mechanism of metallic card clothing,used in textile industry, was analyzed. A fast wear test for metallic card clothing racks was developed, which was used as collecting the wear metal particles. The failure type of card clothing was analyzed by the mean of scanning electron microscopy (SEM) and ferro-spectrum technology. The results show that the main wear mechanism of metallic card clothing is low load and high repetition interval fatigue wear caused by friction force between fiber and metal wire teeth.The appropriate quenching microstmcture, which improves the wear resistance of the metallic card clothing rack is also discussed.

  14. The Delamination Theory of Wear - III

    Science.gov (United States)

    1977-12-01

    117. 18 A. P. Orson , J. Mach. Phys. Solids, 2 (1954) 197 - 211, 19 D. R. Wheeler and D, H. Buckley, Wear, 83 (1975) 65. 20 V. C, Scott end H. Wilman...papers were also published In Volume 44 no. I of the Journal Wear, edited by1). Scott . "ELSEVIER SEQUOIA S.A., LAUSANNE, 1977 APproved for public ioleoee...possible without the enthusiasm and support of Messrs. Douglas Scott and VOrnon C, Westoott. This kind of research cannot reodily be undertaken at a

  15. Consideration of wear rates at high velocity

    Science.gov (United States)

    Hale, Chad S.

    The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. Overall, the wear environment is truly three-dimensional. The attempt to characterize three-dimensional wear was not economically feasible because it must be analyzed at the micro-mechanical level to get results. Thus, an engineering approximation was carried out. This approximation was based on a metallographic study identifying the need to include viscoplasticity constitutive material models, coefficient of friction, relationships between the normal load and velocity, and the need to understand wave propagation. A sled test run at the Holloman High Speed Test Track (HHSTT) was considered for the determination of high velocity wear rates. In order to adequately characterize high velocity wear, it was necessary to formulate a numerical model that contained all of the physical events present. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were analyzed. During this rocket sled test, the slipper traveled 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s. This type of environment was never considered previously in terms of wear evaluation. Each of the features of the metallography were obtained through micro-mechanical experimental techniques. The byproduct of this analysis is that it is now possible to formulate a model that contains viscoplasticity, asperity collisions, temperature and frictional features. Based on the observations of the metallographic analysis, these necessary features have been included in the numerical model, which makes use of a time-dynamic program which follows the movement of a slipper during its experimental test run. The resulting velocity and pressure functions of time have been implemented in the explicit finite element code, ABAQUS. Two-dimensional, plane strain models

  16. Wear Analysis of Wind Turbine Gearbox Bearings

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL; Walker, Larry R [ORNL; Xu, Hanbing [ORNL; Parten, Randy J [ORNL; Qu, Jun [ORNL; Geer, Tom [ORNL

    2010-04-01

    The objective of this effort was to investigate and characterize the nature of surface damage and wear to wind turbine gearbox bearings returned from service in the field. Bearings were supplied for examination by S. Butterfield and J. Johnson of the National Wind Technology Center (NREL), Boulder, Colorado. Studies consisted of visual examination, optical and electron microscopy, dimensional measurements of wear-induced macro-scale and micro-scale features, measurements of macro- and micro-scale hardness, 3D imaging of surface damage, studies of elemental distributions on fracture surfaces, and examinations of polished cross-sections of surfaces under various etched and non-etched conditions.

  17. Gradient Index in Wear Debris Image Collection

    Institute of Scientific and Technical Information of China (English)

    LVZhi-yong; GAOHui-liang; YANXin-ping

    2004-01-01

    In order to solve a problem of oil on-line monitoring, this instrument adopts a prinripium of self-focus lens of Gradieat index fiber( GRIN Len) to design optics system and magnetic circuit. For the magnetic circuit, the monitor can catch particle wear debris in oil. And for the optics circuit. GRIN Len can transfer image of debris to apparatus of gather image, e . g, CCD and camera. And the image of debris is transferred to computer for analyzing seize and physiognomy of debris. The character of the monitor is of micro weight, micro volume andcurve imaging And it is directly pluged into oil to catch image of wear particles.

  18. Surface engineering for enhanced performance against wear

    CERN Document Server

    2013-01-01

    Surface Engineering constitutes a variety of processes and sub processes. Each chapter of this work covers specific processes by experts working in the area. Included for each topic are tribological performances for each process as well as results of recent research. The reader also will benefit from in-depth studies of diffusion coatings, nanocomposite films for wear resistance, surfaces for biotribological applications, thin-film wear, tribology of thermal sprayed coatings, hardfacing, plating for tribology and high energy beam surface modifications. Material scientists as well as engineers working with surface engineering for tribology will be particularly interested in this work.

  19. Wear behaviour of laser melted an ion implanted materials.

    NARCIS (Netherlands)

    Beurs, Hans de

    1988-01-01

    The emphasis in this thesis is on the development of wear resistant materials by laser melting. Furthermore, the principle aim is to search for the dislocation characteristics common to the wear process in heterogeneous materials. ... Zie: Summary

  20. Comparison of two measurement techniques for clinical wear

    DEFF Research Database (Denmark)

    Peters, M C; Delong, R; Pintado, M R

    1999-01-01

    Clinical wear of restorations is generally evaluated by marginal integrity over time. In this study, both a subjective and an objective method for wear assessment are compared, and the relative advantages and disadvantages of each are considered....

  1. Interactions between nonlinear spur gear dynamics and surface wear

    Science.gov (United States)

    Ding, Huali; Kahraman, Ahmet

    2007-11-01

    In this study, two different dynamic models, a finite elements-based deformable-body model and a simplified discrete model, and a surface wear model are combined to study the interaction between gear surface wear and gear dynamic response. The proposed dynamic gear wear model includes the influence of worn surface profiles on dynamic tooth forces and transmission error as well as the influence of dynamic tooth forces on wear profiles. This paper first introduces the nonlinear dynamic models that include gear backlash and time-varying gear mesh stiffness, and a wear model separately. It presents a comparison to experiments for validation of the dynamic models. The dynamic models are combined with the wear model to study the interaction of surface wear and dynamic behavior in both linear and nonlinear response regimes. At the end, several sets of simulation results are used to demonstrate the two-way relationship between nonlinear gear dynamics and surface wear.

  2. ERRATUM: Work smart, wear your hard hat

    CERN Multimedia

    2003-01-01

    An error appeared in the article «Work smart, wear your hard hat» published in Weekly Bulletin 27/2003, page 5. The impact which pierced a hole in the hard hat worn by Gerd Fetchenhauer was the equivalent of a box weighing 5 kg and not 50 kg.

  3. Reciprocating wear in a steam environment

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.J.; Gee, M.G. [National Physical Laboratory, Teddington, Middlesex (United Kingdom)

    2010-07-01

    Tests to simulate the wear between sliding components in steam power plant have been performed using a low frequency wear apparatus at elevated temperatures under static load, at ambient pressure, in a steam environment. The apparatus was modified to accept a novel method of steam delivery. The materials tested were pre-exposed in a flowing steam furnace at temperature for either 500 or 3000 hours to provide some simulation of long term ageing. The duration of each wear test was 50 hours and tests were also performed on as-received material for comparison purposes. Data has been compared with results of tests performed on non-oxidised material for longer durations and also on tests without steam to examine the effect of different environments. Data collected from each test consists of mass change, stub height measurement and friction coefficient as well as visual inspection of the wear track. Within this paper, it is reported that both pre-ageing and the addition of steam during testing clearly influence the friction between material surfaces. (orig.)

  4. Saliva parameters and erosive wear in adolescents

    NARCIS (Netherlands)

    Zwier, N.; Huysmans, M.C.D.N.J.M.; Jager, D.H.J.; Ruben, J.; Bronkhorst, E.M.; Truin, G.J.

    2013-01-01

    The aim of this study was to investigate the relationship between several parameters of saliva and erosive wear in adolescents. (Un-)stimulated saliva was collected from 88 adolescents with erosion and 49 controls (age 16 ± 1 years). Flow rate, pH and buffer capacity were determined immediately.

  5. Saliva Parameters and Erosive Wear in Adolescents

    NARCIS (Netherlands)

    Zwier, N.; Huysmans, M. C. D. N. J. M.; Jager, D. H. J.; Ruben, J.; Bronkhorst, E. M.; Truin, G. J.

    2013-01-01

    The aim of this study was to investigate the relationship between several parameters of saliva and erosive wear in adolescents. (Un-)stimulated saliva was collected from 88 adolescents with erosion and 49 controls (age 16 +/- 1 years). Flow rate, pH and buffer capacity were determined immediately.

  6. Healthy Contact Lens Wear and Care

    Centers for Disease Control (CDC) Podcasts

    2014-02-04

    In this podcast, CDC’s Dr. Jennifer Cope explains some basic steps for proper wear and care of soft contact lenses.  Created: 2/4/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/4/2014.

  7. Friction and wear of human hair fibres

    Science.gov (United States)

    Bowen, James; Johnson, Simon A.; Avery, Andrew R.; Adams, Michael J.

    2016-06-01

    An experimental study of the tribological properties of hair fibres is reported, and the effect of surface treatment on the evolution of friction and wear during sliding. Specifically, orthogonally crossed fibre/fibre contacts under a compressive normal load over a series of 10 000 cycle studies are investigated. Reciprocating sliding at a velocity of 0.4 mm s-1, over a track length of 0.8 mm, was performed at 18 °C and 40%-50% relative humidity. Hair fibres retaining their natural sebum were studied, as well as those stripped of their sebum via hexane cleaning, and hair fibres conditioned using a commercially available product. Surface topography modifications resulting from wear were imaged using scanning electron microscopy and quantified using white light interferometry. Hair fibres that presented sebum or conditioned product at the fibre/fibre junction exhibited initial coefficients of friction at least 25% lower than those that were cleaned with hexane. Coefficients of friction were observed to depend on the directionality of sliding for hexane cleaned hair fibres after sufficient wear cycles that cuticle lifting was present, typically on the order 1000 cycles. Cuticle flattening was observed for fibre/fibre junctions exposed to 10 mN compressive normal loads, whereas loads of 100 mN introduced substantial cuticle wear and fibre damage.

  8. Tribology: Friction, lubrication, and wear technology

    Science.gov (United States)

    Blau, Peter J.

    1993-01-01

    The topics are presented in viewgraph form and include the following: introduction and definitions of terms; friction concepts; lubrication technology concepts; wear technology concepts; and tribological transitions. This document is designed for educators who seek to teach these concepts to their students.

  9. Powdered Hexagonal Boron Nitride Reducing Nanoscale Wear

    Science.gov (United States)

    Chkhartishvili, L.; Matcharashvili, T.; Esiava, R.; Tsagareishvili, O.; Gabunia, D.; Margiev, B.; Gachechiladze, A.

    2013-05-01

    A morphology model is suggested for nano-powdered hexagonal boron nitride that can serve as an effective solid additive to liquid lubricants. It allows to estimate the specific surface, that is a hard-to-measure parameter, based on average size of powder particles. The model can be used also to control nanoscale wear processes.

  10. Corrosive wear. Evaluation of wear and corrosive resistant materials; Noetningskorrosion. Utvaerdering av noetnings- och korrosionsbestaendiga material

    Energy Technology Data Exchange (ETDEWEB)

    Persson, H.; Hjertsen, D.; Waara, P.; Prakash, B.; Hardell, J.

    2007-12-15

    With a new purchase of a waste conveyer screw at hand, for the 'A-warehouse' at the combined power and heating plant at E.ON Norrkoeping, the request for improved construction materials was raised. The previous screw required maintenance with very short intervals due to the difficult operation conditions. With the new screw the expectation is to manage 6 months of operation without interruption. The environment for the screw has two main components that sets the demand on the materials, on one hand the corrosive products that comes along and which forms at digestion of the waste and on the other hand the abrasive content in the waste. The term of the mechanism is wear-corrosion and can give considerably higher material loss than the two mechanisms wear and corrosion separately. Combination of a strong corrosive environment together with extensive wear is something that we today have limited knowledge about. The overall objective of the project has been to establish better wear and corrosive resistant construction materials for a waste conveyer screw that will lead to reduced operational disturbance costs. The evaluation has been performed in both controlled laboratory environments and in field tests, which has given us a better understanding of what materials are more suitable in this tough environment and has given us a tool for future predictions of the wear rate of the different material. The new conveyer screw, installed in February 2007 and with which the field test have been performed, has considerably reduced the wear of the construction and the target of 6 month maintenance-free operation is met with this screw for all the evaluated materials. The wear along the screw varies very much and with a clear trend for all the materials to increase towards the feeding direction of the screw. As an example, the wear plate SS2377 (stainless duplex steel) has a useful life at the most affected areas that is calculated to be 1077 days of operation with the

  11. Structurally Integrated Coatings for Wear and Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Beardsley, M. Brad; Sebright, Jason L.

    2008-11-18

    Wear and corrosion of structures cuts across industries and continues to challenge materials scientists and engineers to develop cost effective solutions. Industries typically seek mature technologies that can be implemented for production with rapid or minimal development and have little appetite for the longer-term materials research and development required to solve complex problems. The collaborative work performed in this project addressed the complexity of this problem in a multi-year program that industries would be reluctant to undertake without government partnership. This effort built upon the prior development of Advanced Abrasion Resistant Materials conduct by Caterpillar Inc. under DOE Cooperative Agreement No. DE-FC26-01NT41054. In this referenced work, coatings were developed that exhibited significant wear life improvements over standard carburized heat treated steel in abrasive wear applications. The technology used in this referenced work, arc lamp fusing of thermal spray coatings, was one of the primary technical paths in this work effort. In addition to extending the capability of the coating technology to address corrosion issues, additional competitive coating technologies were evaluated to insure that the best technology was developed to meet the goals of the program. From this, plasma transferred arc (PTA) welding was selected as the second primary technology that was investigated. Specifically, this project developed improved, cost effective surfacing materials and processes for wear and corrosion resistance in both sliding and abrasive wear applications. Materials with wear and corrosion performance improvements that are 4 to 5 times greater than heat treated steels were developed. The materials developed were based on low cost material systems utilizing ferrous substrates and stainless steel type matrix with hard particulates formed from borides and carbides. Affordability was assessed against other competing hard surfacing or coating

  12. STUDY ON WEAR AND DESTRUCTION OF HOB IN GEAR HOBBING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The wear and destruction appearances of hobs are researched. The reasons of the wear and destruction of hobare analyzed. And the influence of the change of the hobbing force and the hobbing temperature on the wear and destruc-tion of hob in gear hobbing is also analyzed. In gear hobbing, the main wear mechanisms are adhesion and ploughingwhen cutting the 20CrMnTi gear using W 18Cr4V high-speed steel hob.

  13. New synthesizing feature parameter of wear particles image

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper outlines the application of wavelet analysis method to computering wear par-ticles image processing and introduces the concept of grain parameter for wear particle imagebased on statistical feature parameters. The feature of wear particles image can be obtained fromthe wavelet decomposition and the statistics analysis. Test results showed that grain parametercan be used as a synthesizing feature parameter for wear particle image.

  14. A panorama of tooth wear during the medieval period.

    Science.gov (United States)

    Esclassan, Rémi; Hadjouis, Djillali; Donat, Richard; Passarrius, Olivier; Maret, Delphine; Vaysse, Frédéric; Crubézy, Eric

    2015-01-01

    Tooth wear is a natural phenomenon and a universal occurrence that has existed from the origin of humankind and depends on the way of life, especially diet. Tooth wear was very serious in ancient populations up to the medieval period. The aim of this paper is to present a global view of tooth wear in medieval times in Europe through different parameters: scoring systems, quantity and direction of wear, gender, differences between maxilla and mandible, relations with diet, caries, tooth malpositions and age.

  15. An On-line Ferrograph for Monitoring Machine Wear

    Institute of Scientific and Technical Information of China (English)

    L(U) Xiao-jun; JING Min-qing; XIE You-bai

    2005-01-01

    In order to improve an on-line ferrograph, this paper simulates a three dimensional magnetic field distribution of an electromagnet, builds a sinking motion model of a wear particle, and investigates the motion law of wear particles under two different conditions. Both numeric results and experimental results show that the on-line ferrograph is capable of monitoring machine wear conditions by measuring the concentration and size distribution of wear particles in lubricating oil.

  16. Wear numbers for ball cup and journal bearings

    OpenAIRE

    Ligterink, D.J.; Moes, H.

    1980-01-01

    A wear number is defined for ball cup bearings and for journal bearings where the cup and the cylindrical bearing are made of soft material. This dimensionless wear number provides a relation between the following five quantities: the radius of the ball or the length of the journal bearing in millimetres, the wear modulus in newtons per square millimetre, the maximum wear depth rate of the cup or the cylindrical bearing in millimetres per second, the force between the mating surfaces in newto...

  17. Sliding Wear and Fretting Wear of DLC-Based, Functionally Graded Nanocomposite Coatings

    Science.gov (United States)

    Miyoshi, K.; Pohlchuck, B.; Street, Kenneth W.; Zabinski, J. S.; Sanders, J. H.; Voevodin, A. a.; Wu, R. L. C.

    1999-01-01

    Improving the tribological functionality of diamondlike carbon (DLC) films--developing, good wear resistance, low friction, and high load-carrying capacity-was the aim of this investigation. Nanocomposite coatings consisting of an amorphous DLC (a-DLC) top layer and a functionally graded titanium-titanium carbon-diamondlike carbon (Ti-Ti(sub x) C(sub y)-DLC) underlayer were produced on AISI 440C stainless steel substrates by the hybrid technique of magnetron sputtering and pulsed-laser deposition. The resultant DLC films were characterized by Raman spectroscopy, scanning electron microscopy, and surface profilometry. Two types of wear experiment were conducted in this investioation: sliding friction experiments and fretting wear experiments. Unidirectional ball-on-disk sliding friction experiments were conducted to examine the wear behavior of an a-DLC/Ti-Ti(sub x) C(sub y)-DLC-coated AISI 440C stainless steel disk in sliding contact with a 6-mm-diameter AISI 440C stainless steel ball in ultrahigh vacuum, dry nitrogen, and humid air. Although the wear rates for both the coating and ball were low in all three environments, the humid air and dry nitrogen caused mild wear with burnishing, in the a-DLC top layer, and the ultrahigh vacuum caused relatively severe wear with brittle fracture in both the a-DLC top layer and the Ti-Ti(sub x) C(sub y)-DLC underlayer. For reference, amorphous hydrogenated carbon (H-DLC) films produced on a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coatings by using an ion beam were also examined in the same manner. The H-DLC films markedly reduced friction even in ultrahigh vacuum without sacrificing wear resistance. The H-DLC films behaved much like the a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coating in dry nitrogen and humid air, presenting low friction and low wear. Fretting wear experiments were conducted in humid air (approximately 50% relative humidity) at a frequency of 80 Hz and an amplitude of 75 micron on an a

  18. Severe tooth wear: European consensus statement on management guidelines

    DEFF Research Database (Denmark)

    Loomans, Bas AC; Opdam, Niek JM; Attin, Thomas

    2017-01-01

    This paper reports a European expert consensus statement on guidelines for the management of severe tooth wear. It focuses on the definition of physiological versus pathological tooth wear and recommends diagnosis, monitoring and counseling to define the activity of the wear. Restorative...

  19. 16 CFR 423.6 - Textile wearing apparel.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Textile wearing apparel. 423.6 Section 423.6 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES CARE LABELING OF TEXTILE WEARING APPAREL AND CERTAIN PIECE GOODS AS AMENDED § 423.6 Textile wearing apparel. This section applies to...

  20. An Investigation into the Behavior of Disc Blake Wear

    Directory of Open Access Journals (Sweden)

    Muneer A. H.Jassim

    2007-01-01

    Full Text Available A real method of predication brake pad wear ,could lead to substantiol economies of time and money. This paper describes how such a procedure has been used and gives the results to establish is reliability by comparing the predicted wear with that which actually occurs in an existing service. The experimental work was carried out on three different commercial samples ,tested under different operation conditions (speed,load,time...etcusing a test ring especially modified for this purpose. Abrasive wear is mainly studied , since it is the type of wear that takes place in such arrangements. Samples wear tested in presences of sand or mud between the mating surfaces under different operational conditions of speed, load and braking time .Mechanical properties of the pad material samples (hardness, young,s modulus and collapse load under pure bending condition wear established . The thermal conductivity and surface roughness of the pad material wear also found in order to enable comparison between the surface condition before and after testing. Sliding velocity had a small effect on the wear rate but it had great effect on friction coefficient. Wear rate was affected mainly by the surface temperature which causing a reduction friction coefficient and increasing the wear rate. Surface roughness had almost no effect on the wear rate since it was proved experimentally ,that the surface becomes softer during operation .mechanical properties of the pad material had fluctuating effect on wear rate. The existence of solid particles between pad and disc increasing wear rate and friction coefficient while the mud caused a reduction in wear rate of the pad surface since it acts as a lubricant absorbing the surface heat generated during sliding the area of contact between pad and disc. wear rate obtained experimentally agreed fairly well that found from empirically obtained equations.

  1. Is tooth wear in the primary dentition predictive of tooth wear in the permanent dentition? Report from a longitudinal study.

    LENUS (Irish Health Repository)

    Harding, M A

    2010-03-01

    To determine the prevalence of tooth wear in the permanent dentition of a sample of 12-year-old school children and establish whether an association exists between tooth wear recorded now and tooth wear recorded in their primary dentition at age five.

  2. Wear Studies on Metal Matrix Composites: a Taguchi Approach

    Institute of Scientific and Technical Information of China (English)

    S. Basavarajappa; G. Chandramohan

    2005-01-01

    An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance and percentage of reinforcement on the dry sliding wear of the metal matrix composites. A plan of experiments,based on techniques of Taguchi, was pedormed to acquire data in controlled way. An orthogonal array and the analysis of variance were employed to investigate the influence of process parameters on the wear of composites. The objective is to establish a correlation between dry sliding wear of composites and wear parameters. These correlations were obtained by multiple regressions. Finally, confirmation tests were conducted to verify the experimental results foreseen from the mentioned correlations.

  3. Contact Thermal Analysis and Wear Simulation of a Brake Block

    Directory of Open Access Journals (Sweden)

    Nándor Békési

    2013-01-01

    Full Text Available The present paper describes an experimental test and a coupled contact-thermal-wear analysis of a railway wheel/brake block system through the braking process. During the test, the friction, the generated heat, and the wear were evaluated. It was found that the contact between the brake block and the wheel occurs in relatively small and slowly moving hot spots, caused by the wear and the thermal effects. A coupled simulation method was developed including numerical frictional contact, transient thermal and incremental wear calculations. In the 3D simulation, the effects of the friction, the thermal expansion, the wear, and the temperature-dependent material properties were also considered. A good agreement was found between the results of the test and the calculations, both for the thermal and wear results. The proposed method is suitable for modelling the slowly oscillating wear caused by the thermal expansions in the contact area.

  4. 7-Be Implantation in Plastics for Prosthesis Wear Studies

    Science.gov (United States)

    Greife, Uwe; Erikson, L.; Patel, N.; Wimmer, M.; Dwiwedi, Y.; Laurent, M.; Chipps, K.; Blackmon, J.; Kozub, R.; Bardayan, D.; Gross, C.; Stracener, D.; Smith, M.; Nesaraya, C.; Rehm, E.; Ahmed, I.; Greene, J.

    2010-11-01

    The current generation of highly cross linked ultrahigh molecular weight polyethylenes (PE) for hip and knee joint replacement have achieved such low in vitro wear rates that efforts have been underway to develop more sensitive methods to measure polyethylene wear. The most widely used technique, the gravimetric method, suffers from the notable disadvantage that mass gain by fluid absorption can considerably exceed mass loss by wear, making the wear measurement inaccurate, sometimes even leading to negative ``wear'' values. The purpose of this experiment was to investigate the use of a radioactive tracer, beryllium-7 (7-Be), to circumvent the problem of fluid absorption and thereby achieve a much more sensitive and accurate wear measurement. This proof of principle study demonstrated the general feasibility of 7-Be implantation (performed at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory) for PE wear analysis.

  5. Dynamic SEM wear studies of tungsten carbide cermets

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined. Etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the WC and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation. The wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

  6. Wear aspects of internal combustion engine valves

    Science.gov (United States)

    Panţuru, M.; Chicet, D.; Paulin, C.; Alexandru, A.; Munteanu, C.

    2016-08-01

    Because the surface engineering is becoming an increasingly viable alternative to the constructive changes made to improve the efficiency of internal combustion engines, have been proposed and tested various types of coatings of some organs of internal combustion engines. One vital organ is the engine valves, which is subjected during operation to combined thermal, mechanical, corrosion and wear solicitations, which are leading to severe corrosion and complete breakdown. In this paper were analyzed aspects of valves wear and the active surfaces were coated using the atmospheric plasma spraying method (APS) with two commercial powders: Ni-Al and YSZ. Microstructural analyzes were made on these layers and also observations regarding the possibility of using them as thermal barrier and anti-oxidant coatings.

  7. Exposure and risks from wearing asbestos mitts

    Directory of Open Access Journals (Sweden)

    Tindall Matthew

    2005-10-01

    Full Text Available Abstract Background Very high fibre inhalation exposure has been measured while people were wearing personal protective equipment manufactured from chrysotile asbestos. However, there is little data that relates specifically to wearing asbestos gloves or mitts, particularly when used in hot environments such as those found in glass manufacturing. The aim of this study was to assess the likely personal exposure to asbestos fibres when asbestos mitts were used. Results Three types of work activity were simulated in a small test room with unused mitts and artificially aged mitts. Neither pair of mitts were treated to suppress the dust emission. The measured respirable fibre exposure levels ranged from Conclusion People who wore asbestos mitts were likely to have been exposed to relatively low levels of airborne chrysotile asbestos fibres, certainly much lower than the standards that were accepted in the 1960's and 70's. The cancer risks from this type of use are likely to be very low.

  8. Low-Wear Ball-Bearing Separator

    Science.gov (United States)

    Hawkinson, Elden L.

    1991-01-01

    Proposed ball-bearing separator for use in cryogenic pump stronger and more resistant to wear. Consists of molded plastic-and-metal composite ring imbued with solid lubricant and containing embedded metal ring. Obtains combination of strength and lubricity. Before molding and machining, ring includes tooling portion for handling and indexing. Molded composite blend of PTFE and fluorinated ethylene/propylene (FEP) filled with brass and bronze powder and molybdenum disulfide powder.

  9. Wear debris in cemented total hip arthroplasty.

    Science.gov (United States)

    Huo, M H; Salvati, E A; Buly, R L

    1991-03-01

    One of the most prevalent clinical problems in long-term follow up of total hip arthroplasty patients is loosening of prosthetic fixation. Factors contributing to mechanical failure of total hip reconstruction are complex and multiple. It has become increasingly apparent that wear debris from the prosthetic components may contribute significantly to this process. The authors summarize some of the current concepts concerning the detrimental effects of metallic debris in total hip arthroplasty.

  10. Wear Resistant Rubber Tank Track Pads

    Science.gov (United States)

    1975-10-01

    stereospecific SBR (Stereon 750), SBR/polybutadiene blends (Fhilprene 1609/Cis-4 1350 (or Cis-4 1351), Ameripoi 1834/Ameripol CB 1352) and alfin ...polybutadiene blends has confirmed this improvement in tread wear. The uncertainty regarding the future commercial availibility of the alfin catalyzed...polybutadiene blend) (S212-2), and HYTRANS 1227-2S9-1 ( alfin catalyzed copolymer of butadiene/ styrene) (S223-4) to determine their effect on the resistance to

  11. A Predictive Multiscale Model of Wear

    Science.gov (United States)

    2011-03-09

    of Robust Protective Coatings for Metal Components Subjected to Extreme Conditions,” at the Computer Aided Molecular Design Conference, St. Johns...2006 to July 31, 2010 on developing and applying first principles quantum mechanics methods to describe mechanical wear of chrome -plated steel gun...than the corresponding value for Fe3+, which makes sense since Fe’s orbitals are more contracted than Cr’s due to Fe’s larger effective nuclear charge

  12. Wear measurement by surface layer activation

    Energy Technology Data Exchange (ETDEWEB)

    Blatchley, C.

    1987-05-01

    The purpose of these projects was to demonstrate the capability for precisely but remotely measuring small increments of wear, erosion or corrosion in utility components using detectors mounted outside the system to monitor the presence of radionuclide surface markers. These gamma ray emitting markers are produced by surface layer activation (SLA) using a high energy particle beam from a Van de Graaff or cyclotron particle accelerator. The work was divided into three major projects: (1) determination of the feasibility of applying SLA based surface monitoring techniques to key power plant systems; (2) a field demonstration of SLA monitoring in steam turbine components subject to severe solid particle erosion; and (3) a field demonstration of SLA wear or corrosion monitoring of components in boiler auxiliaries. In the field tests, surface material removal was successfully measured from both selected systems, demonstrating the feasibility of the technique for long term diagnostic condition monitoring. Three bearing components in a boiler circulation pump were monitored almost continuously for a period of over 5 months until the pump was stopped due to electrical problems unrelated to the wear measurements. Solid particle erosion from two stop valve bypass valves was measured during a series of nine startup cycles. Both test demonstrations confirmed the earlier feasibility estimates and showed how SLA markers can be used to provide valuable diagnostic information to plant operators. 22 refs., 63 figs., 29 tabs.

  13. Study of Wear of Pitched Blade Impellers

    Directory of Open Access Journals (Sweden)

    I. Fořt

    2000-01-01

    Full Text Available A study was made of the erosion of blades of pitched blade impellers in a suspension of solid particles in a liquid under a turbulent regime of flow of an agitated charge. The wear of the impeller is described by an analytical approximation in exponential form, and the influence of the pitch angle on the impeller blade wear was studied experimentally. It follows from the results of the experiments made that the wear rate of the pitched blade impellers increases linearly with the decreasing pitch angle within the interval a Î á15°; 45° ń. The proposed form of radial profile of the leading edge of the impeller blade enables us to calculate the surface of the worn blade. This quantity significantly decreases with the length of the period when the blades are affected by the solid particles, and its values calculated according to the suggested profile of the worn blade fit fairly well with the experimentally determined values. The results of the experiments performed are valid for homogeneous distribution of solid particles in an agitated suspension.

  14. Corrosion and wear in plasma electrosurgical devices

    Science.gov (United States)

    Gaspredes, J.; Ryan, T. P.; Stalder, K. R.; Woloszko, J.

    2017-02-01

    Data were previously reported on studies of the effects of electrical discharges on the corrosion and wear of simple, single-wire test devices immersed in isotonic saline 1 . This work showed that there are a wide variety of mechanisms that can explain various aspects of electrode mass loss, even with very simple electrode geometries and operating conditions. It was found that the electrode material composition played an important role. Subsequently, our studies were expanded to include more realistic device geometries and operating conditions. This paper shows the results of studies on wear characteristics of electrodes made from a variety of highly corrosion resistant metals and alloys, including Waspaloy, Hastelloy, Inconel, Havar, Monel, and other pure metals such as Hafnium. All of these metals underwent wear testing under clinically relevant conditions. Depending on the operating conditions, multiple discrete physical and chemical effects were observed at different locations on the surface of an individual millimeter-scale device electrode. Scanning electron microscope (SEM) micrographs, Energy-dispersive X-ray spectroscopy (EDS) and area loss data will be presented for a variety of test conditions and electrode materials.

  15. Structurally Integrated Coatings for Wear and Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Beardsley, M. Brad; Sebright, Jason L.

    2008-11-18

    Wear and corrosion of structures cuts across industries and continues to challenge materials scientists and engineers to develop cost effective solutions. Industries typically seek mature technologies that can be implemented for production with rapid or minimal development and have little appetite for the longer-term materials research and development required to solve complex problems. The collaborative work performed in this project addressed the complexity of this problem in a multi-year program that industries would be reluctant to undertake without government partnership. This effort built upon the prior development of Advanced Abrasion Resistant Materials conduct by Caterpillar Inc. under DOE Cooperative Agreement No. DE-FC26-01NT41054. In this referenced work, coatings were developed that exhibited significant wear life improvements over standard carburized heat treated steel in abrasive wear applications. The technology used in this referenced work, arc lamp fusing of thermal spray coatings, was one of the primary technical paths in this work effort. In addition to extending the capability of the coating technology to address corrosion issues, additional competitive coating technologies were evaluated to insure that the best technology was developed to meet the goals of the program. From this, plasma transferred arc (PTA) welding was selected as the second primary technology that was investigated. Specifically, this project developed improved, cost effective surfacing materials and processes for wear and corrosion resistance in both sliding and abrasive wear applications. Materials with wear and corrosion performance improvements that are 4 to 5 times greater than heat treated steels were developed. The materials developed were based on low cost material systems utilizing ferrous substrates and stainless steel type matrix with hard particulates formed from borides and carbides. Affordability was assessed against other competing hard surfacing or coating

  16. Wear Behaviour of Pressible Lithium Disilicate Glass Ceramic

    Science.gov (United States)

    Peng, Zhongxiao; Rahman, Muhammad Izzat Abdul; Zhang, Yu; Yin, Ling

    2015-01-01

    This paper reports effects of surface preparation and contact loads on abrasive wear properties of highly aesthetic and high-strength pressible lithium disilicate glass-ceramics (LDGC). Abrasive wear testing was performed using a pin-on-disk device in which LDGC disks prepared with different surface finishes were against alumina pins at different contact loads. Coefficients of friction and wear volumes were measured as functions of initial surface finishes and contact loads. Wear-induced surface morphology changes in both LDGC disks and alumina pins were characterized using 3D laser scanning microscopy, scanning electron microscopy and energy dispersive x-ray spectroscopy. The results show that initial surface finishes of LDGC specimens and contact loads significantly affected the friction coefficients, wear volumes and wear-induced surface roughness changes of the material. Both wear volumes and friction coefficients of LDGC increased as the load increased while surface roughness effects were complicated. For rough LDGC surfaces, three-body wear was dominant while for fine LDGC surfaces, two-body abrasive wear played a key role. Delamination, plastic deformation and brittle fracture were observed on worn LDGC surfaces. The adhesion of LDGC matrix materials to alumina pins was also discovered. This research has advanced our understanding of the abrasive wear behaviour of LDGC and will provide guidelines for better utilisation and preparation of the material for long-term success in dental restorations. PMID:25980530

  17. Finite element based simulation of dry sliding wear

    Science.gov (United States)

    Hegadekatte, V.; Huber, N.; Kraft, O.

    2005-01-01

    In order to predict wear and eventually the life-span of complex mechanical systems, several hundred thousand operating cycles have to be simulated. Therefore, a finite element (FE) post-processor is the optimum choice, considering the computational expense. A wear simulation approach based on Archard's wear law is implemented in an FE post-processor that works in association with a commercial FE package, ABAQUS, for solving the general deformable-deformable contact problem. Local wear is computed and then integrated over the sliding distance using the Euler integration scheme. The wear simulation tool works in a loop and performs a series of static FE-simulations with updated surface geometries to get a realistic contact pressure distribution on the contacting surfaces. It will be demonstrated that this efficient approach can simulate wear on both two-dimensional and three-dimensional surface topologies. The wear on both the interacting surfaces is computed using the contact pressure distribution from a two-dimensional or three-dimensional simulation, depending on the case. After every wear step the geometry is re-meshed to correct the deformed mesh due to wear, thus ensuring a fairly uniform mesh for further processing. The importance and suitability of such a wear simulation tool will be enunciated in this paper.

  18. Association between Severity of Tooth Wear and Dentinal Hypersensitivity

    Directory of Open Access Journals (Sweden)

    Ashok Ayer

    2016-11-01

    Full Text Available Background & Objectives: Tooth wear (attrition, abrasion, erosion, and abfraction is perceived globally as ever increasing problem. Several outcome of the tooth wear are hypersensitivity, esthetic problems, functional impairment, annoyance to the patient, and fracture of the tooth. Among these, the measurable and more commonly reported outcome is hypersensitivity to stimuli. Although dentin hypersensitivity is a common clinical condition and is generally reported by the patient after experiencing a sharp, short pain caused by one of the several different external stimuli, it is often inadequately understood. None of the scientific literature available till date attempted to establish the relationship between tooth wear and dentin hypersensitivity which could be a key factor in monitoring those patients.  The aim of the study was to estimate the association between severity of teeth wear and sensitivity in the patients with reported dentinal hypersensitivity.Materials & Methods: Fifty patients with dentin hypersensitivity were investigated for tooth wear. Tooth wear measured using exact tooth wear index and level of sensitivity to stimuli was recorded using a numerical rating scale. Results: Enamel wear at cervical region of teeth showed a positive correlation (p=.010, similarly, dentin wear at cervical region of teeth showed positive correlation and significant association (p<.001 with dentinal hypersensitivity.Conclusion: The observation supports a significant association between severities of tooth surface wear and dentinal hypersensitivity.

  19. ON ASSESSMNENT OF PHYSICAL WEAR IN ELEMENTS OF TECHNICAL DEVICES

    Directory of Open Access Journals (Sweden)

    S. N. Osipov

    2015-01-01

    Full Text Available Real assessment of wear in technical devices, construction structures, minings, their elements and connections is of great importance for provision of operational security and efficiency. Natural properties of the overwhelming majority of materials follow to probabilistic (stochastic laws due to various reasons (external influence, processing technologies and others. An assessment of physical wear rate of buildings and structures and their elements is carried out in the former republics of the USSR mainly in accordance with external physical signs (deflections, cracks, layer separations, etc. but wear percentage is often calculated on the basis of replacement cost in comparison with the initial one even without taking into account inflation which did not officially exist in the USSR. In this case destruction or failure of structure or their elements are considered as 100 % wear.The paper proposes a new methodology for assessment of physical wear rate in accordance with probability ratio of nofailure operation (reliability, minimum ratio is assigned to admissible limit value in conformity with technical requirements for the technical devices, construction structures, minings in question, their elements and connections. In this context minimum permissible wear probability (reliability is taken as 100 % wear rate and its initial index is considered as 0 % wear rate. That is why wear intensity in time depends on type of value probability distribution while determining the rate of physical property. The proposed methodology is intended for probabilistic wear assessment in case of relatively simple changes in strength properties of materials (for example, within the elastic limit.

  20. Wear characterization of abrasive waterjet nozzles and nozzle materials

    Science.gov (United States)

    Nanduri, Madhusarathi

    Parameters that influence nozzle wear in the abrasive water jet (AWJ) environment were identified and classified into nozzle geometric, AWJ system, and nozzle material categories. Regular and accelerated wear test procedures were developed to study nozzle wear under actual and simulated conditions, respectively. Long term tests, using garnet abrasive, were conducted to validate the accelerated test procedure. In addition to exit diameter growth, two new measures of wear, nozzle weight loss and nozzle bore profiles were shown to be invaluable in characterizing and explaining the phenomena of nozzle wear. By conducting nozzle wear tests, the effects of nozzle geometric, and AWJ system parameters on nozzle wear were systematically investigated. An empirical model was developed for nozzle weight loss rate. To understand the response of nozzle materials under varying AWJ system conditions, erosion tests were conducted on samples of typical nozzle materials. The effect of factors such as jet impingement angle, abrasive type, abrasive size, abrasive flow rate, water pressure, traverse speed, and target material was evaluated. Scanning electron microscopy was performed on eroded samples as well as worn nozzles to understand the wear mechanisms. The dominant wear mechanism observed was grain pullout. Erosion models were reviewed and along the lines of classical erosion theories a semi-empirical model, suitable for erosion of nozzle materials under AWJ impact, was developed. The erosion data correlated very well with the developed model. Finally, the cutting efficiency of AWJ nozzles was investigated in conjunction with nozzle wear. The cutting efficiency of a nozzle deteriorates as it wears. There is a direct correlation between nozzle wear and cutting efficiency. The operating conditions that produce the most efficient jets also cause the most wear in the nozzle.

  1. STUDY ON THE WEAR CHARACTERISTICS OF Ni-P BRUSH-PLATING COATING

    Institute of Scientific and Technical Information of China (English)

    WuWenyue; HuangJinruo; QuJinxin; ShaoHesheng

    1996-01-01

    This paper studied the wear characteristics as well as the wear mechanismof the Ni-P alloy brush-plating coating by means of sliding-wear tests, SEM and X-Ray analyses. The results show that Ni-Palloy coating has excellent wear-ability inhigh temperature, and the wear mechanism of the coating is that both the adhesivewear and abrasive wear exist in a boundary lubrication condition. The wear model wasbuilt up.

  2. Development and Validation of a Wear Model to Predict Polyethylene Wear in a Total Knee Arthroplasty: A Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    Bernardo Innocenti

    2014-11-01

    Full Text Available Ultra-high molecular weight polyethylene (UHMWPE wear in total knee arthroplasty (TKA components is one of the main reasons of the failure of implants and the consequent necessity of a revision procedure. Experimental wear tests are commonly used to quantify polyethylene wear in an implant, but these procedures are quite expensive and time consuming. On the other hand, numerical models could be used to predict the results of a wear test in less time with less cost. This requires, however, that such a model is not only available, but also validated. Therefore, the aim of this study is to develop and validate a finite element methodology to be used for predicting polyethylene wear in TKAs. Initially, the wear model was calibrated using the results of an experimental roll-on-plane wear test. Afterwards, the developed wear model was applied to predict patello-femoral wear. Finally, the numerical model was validated by comparing the numerically-predicted wear, with experimental results achieving good agreement.

  3. Sliding wear and friction behaviour of zircaloy-4 in water

    Science.gov (United States)

    Sharma, Garima; Limaye, P. K.; Jadhav, D. T.

    2009-11-01

    In water cooled nuclear reactors, the sliding of fuel bundles in fuel channel handling system can lead to severe wear and it is an important topic to study. In the present study, sliding wear behaviour of zircaloy-4 was investigated in water (pH ˜ 10.5) using ball-on-plate sliding wear tester. Sliding wear resistance zircaloy-4 against SS 316 was examined at room temperature. Sliding wear tests were carried out at different load and sliding frequencies. The coefficient of friction of zircaloy-4 was also measured during each tests and it was found to decrease slightly with the increase in applied load. The micro-mechanisms responsible for wear in zircaloy-4 were identified to be microcutting, micropitting and microcracking of deformed subsurface zones in water.

  4. Ceramic-like wear behaviour of human dental enamel.

    Science.gov (United States)

    Arsecularatne, J A; Hoffman, M

    2012-04-01

    This paper reports a transmission electron microscopy (TEM) analysis of subsurfaces of enamel specimens following in vitro reciprocating wear tests with an enamel cusp sliding on a flat enamel specimen under hydrated conditions. The obtained results show that crack formation occurred in the wear scar subsurface. The path followed by these cracks seems to be dictated either by the histological structure of enamel or by the contact stress field. Moreover, the analysis of a set of enamel wear results obtained from the literature and application of fracture-based models, originally developed for ceramics, correlate well, confirming the similar wear processes taking place in these materials. This analysis also reveals a marked influence of coefficient of friction on the enamel wear rate: for a higher coefficient of friction value, enamel wear can be severe even under forces generated during normal operation of teeth. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. A physically-based abrasive wear model for composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gun Y.; Dharan, C.K.H.; Ritchie, Robert O.

    2001-05-01

    A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the matrix material. The size of this non-contributing portion of the reinforcement is estimated by modeling the three primary wear mechanisms, specifically plowing, interfacial cracking and particle removal. Critical variables describing the role of the reinforcement, such as its relative size and the nature of the matrix/reinforcement interface, are characterized by a single contribution coefficient, C. Predictions are compared with the results of experimental two-body (pin-on drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy matrix composite material.

  6. Fretting wear behavior of AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN An-hua; HUANG Wei-jiu; LI Zhao-feng

    2006-01-01

    The fretting behaviour of the AZ91D magnesium alloy was investigated. The influence of the number of cycles, normal load (contact pressure) and the amplitude of slip on the fretting behavior of the material were focused. Fretting tests were performed under various running conditions with regard to normal load levels and slip amplitudes. The friction coefficient between the surfaces at the fretting junction was continuously recorded. The fretting damage on the magnesium specimens was studied by SEM. The results show that the wear volume increases with the increase of slip amplitude, and linearly increases with the increase of normal load in the mixed and gross slip regime, but the normal load has no obvious effect on the wear volume in the partial slip regime. The predominant fretting wear mechanism of magnesium alloy in the slip regime is the oxidation wear, delaminated wear and abrasive wear.

  7. Control of erosive tooth wear: possibilities and rationale

    Directory of Open Access Journals (Sweden)

    Mônica Campos Serra

    2009-06-01

    Full Text Available Dental erosion is a type of wear caused by non bacterial acids or chelation. There is evidence of a significant increase in the prevalence of dental wear in the deciduous and permanent teeth as a consequence of the frequent intake of acidic foods and drinks, or due to gastric acid which may reach the oral cavity following reflux or vomiting episodes. The presence of acids is a prerequisite for dental erosion, but the erosive wear is complex and depends on the interaction of biological, chemical and behavioral factors. Even though erosion may be defined or described as an isolated process, in clinical situations other wear phenomena are expected to occur concomitantly, such as abrasive wear (which occurs, e.g, due to tooth brushing or mastication. In order to control dental loss due to erosive wear it is crucial to take into account its multifactorial nature, which predisposes some individuals to the condition.

  8. Abrasive wear and surface roughness of contemporary dental composite resin.

    Science.gov (United States)

    Han, Jian-min; Zhang, Hongyu; Choe, Hyo-Sun; Lin, Hong; Zheng, Gang; Hong, Guang

    2014-01-01

    The purpose of this study was to evaluate the abrasive wear and surface roughness of 20 currently available commercial dental composite resins, including nanofilled, supra-nanofilled, nanohybrid and microhybrid composite resins. The volume loss, maximum vertical loss, surface roughness (R(a)) and surface morphology [Scanning electron microscopy (SEM)] were determined after wear. The inorganic filler content was determined by thermogravimetric analysis. The result showed that the volume loss and vertical loss varied among the materials. The coefficients of determination (R(2)) of wear volume loss and filler content (wt%) was 0.283. SEM micrographs revealed nanofilled composites displayed a relatively uniform wear surfaces with nanoclusters protrusion, while the performance of nanohybrid composites varied. The abrasive wear resistance of contemporary dental composite resins is material-dependent and cannot be deduced from its category, filler loading and composite matrix; The abrasive wear resistance of some flowable composites is comparable to the universal/posterior composite resins.

  9. Correlation between Wear Resistance and Lifetime of Electrical Contacts

    Directory of Open Access Journals (Sweden)

    Jian Song

    2012-01-01

    Full Text Available Electrical contacts are usually plated in order to prevent corrosion. Platings of detachable electrical contacts experience wear because of the motion between contacts. Once the protecting platings have been worn out, electrical contacts will fail rapidly due to corrosion or fretting corrosion. Therefore the wear resistance of the platings is a very important parameter for the long lifetime of electrical contacts. Many measures which improve the wear resistance can diminish the conductivity of the platings. Due to the fact that platings of electrical contacts must have both a high wear resistance and a high electrical conductivity, the manufacturing of high performance platings of electrical contacts poses a great challenge. Our study shows firstly the correlation between the wear resistance of platings and lifetime of electrical contacts and then the measures, which improve the wear resistance without impairing the electrical performance of the contacts.

  10. Tool Wear Estimate in Milling Operation by FEM

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Many researches show that, in metal cutting process, tool wear rate depends on some cutting process parameters, such as temperature at tool face, contact pressure and relative sliding velocity at tool/chip and tool/workpiece interfaces. Finite element method(FEM) application enables the estimate of these parameters and the tool wear. A tool wear estimate program based on chip formation and heat transfer analysis is designed and compiled with Python to calculate the wear rate and volume, and update tool geometry according to the tool wear. The progressive flank and crater wears in milling operation are estimated by the program. The FEM code ABAQUS/Explicit and Standard are employed to analyze chip formation and heat transfer process.

  11. Wearable Android Android wear and Google Fit app development

    CERN Document Server

    Mishra, Sanjay M

    2015-01-01

    Software Development/Mobile/Android/Wearable/Fitness Build ""Wearable"" Applications on the Android Wear and Google Fit Platforms This book covers wearable computing and wearable application development particularly for Android Wear (smartwatches) and Google Fit (fitness sensors). It provides relevant history, background and core concepts of wearable computing and ubiquitous computing, as a foundation for designing/developing applications for the Android Wear and Google Fit platforms. This book is intended for Android wearable enthusiasts, technologists and software developers. Gain ins

  12. Wear effects and mechanisms of soot-contaminated automotive lubricants

    OpenAIRE

    Green, D. A.; Lewis, R; Dwyer-Joyce, R.S.

    2006-01-01

    A study has been carried out to investigate the influence of soot-contaminated automotive lubricants in the wear process of a simulated engine valve train contact. Previous research on this topic has been mainly performed from a chemical point of view in fundamental studies, with insufficient relevance to real engine conditions, i.e. load and geometry. This study investigates the conditions under which wear occurs through specimen testing. The objective of the work was to understand the wear ...

  13. THE WEAR RESISTANCE INCREASE OF CHROMIUM CAST IRON

    Directory of Open Access Journals (Sweden)

    V. M. Ilyushenko

    2016-01-01

    Full Text Available The article presents the results of the tests on the wear resistance of chromium cast irons of different compositions obtained in sand forms. It has been shown that increase of the wear resistance and mechanical properties of the cast iron is possible to obtain using the casting in metal molds. A further increase in wear resistance of parts produced in metal molds is possible by changing the technological parameters of casting and alloying by titanium.

  14. Tribocorrosion wear of austenitic and martensitic steels

    Directory of Open Access Journals (Sweden)

    G. Rozing

    2016-07-01

    Full Text Available This paper explores the impact of tribocorrosion wear caused by an aggressive acidic media. Tests were conducted on samples made of stainless steel AISI 316L, 304L and 440C. Austenitic steels were tested in their nitrided state and martensitic in quenched and tempered and then induction hardened state. Electrochemical corrosion resistance testing and analysis of the microstructure and hardness in the cross section was carried out on samples of selected steels. To test the possibility of applying surface modification of selected materials in conditions of use, tests were conducted on samples/parts in a worm press for final pressing.

  15. Cavitation wear resistance of engine bearing materials

    Science.gov (United States)

    Rac, Aleksandar

    1994-04-01

    The resistance to cavitation erosion of aluminum alloy, and cast and sinte-red lead-bronze, materials which are most frequently used for engine bearings, has been evaluated. The tests were carried out in motor oil at a temperature of 80 C, using a magnetostrictive vibratory tester (20 kHz). The results showed that the cavitation erosion resistance was the greatest in cast lead-bronze. On the contrary, sintered lead-bronze, though of the same chemical composition, had the greatest erosion rate. Additionally, the investigation of the overlay plated bearings showed the overlay was nonresistive to this type of wear.

  16. Polyethylene sterilization and production affects wear in total hip arthroplasties.

    Science.gov (United States)

    Faris, Philip M; Ritter, Merrill A; Pierce, Andrew L; Davis, Kenneth E; Faris, Gregory W

    2006-12-01

    Production and package sterilization techniques for the polyethylene used in acetabular components for total hip arthroplasties are known to affect wear. We considered three combinations of techniques: sterilization by radiation in inert gas with isostatically molded polyethylene, in inert gas and ram-extruded polyethylene, and in air with extruded polyethylene. The intent of this study was to confirm that molded polyethylene and polyethylene radiated in inert environments reduce wear rates in vivo, to determine the combination of methods with the least wear, and to determine how much variance in wear is attributable to these methods. We reviewed 150 consecutive total hip arthroplasties done in 133 patients using 28-mm cobalt-chrome femoral heads and polyethylene-lined, titanium, ring-locked acetabular components. The least wear occurred in gamma inert-molded polyethylene components. The mean volumetric wear rates were 52.12 mm3/year for gamma inert-molded, 62.32 mm3/year for gamma inert-extruded, and 66.09 mm3/year for gamma air-extruded polyethylene components. Relative risk assessment found gamma air-extruded and gamma inert-extruded polyethylene components to wear 16% and 11% more than gamma inert-molded polyethylene components, respectively. Gender, body mass index, and age accounted for the greatest amount of the explained variance in volumetric wear (57.5%, 21.6%, and 14.4, respectively), followed by angle of wear (3.4%), and sterilization and production technique (3.2%).

  17. Wear characteristics of a rheocast leaded aluminium metal - metal composite

    Energy Technology Data Exchange (ETDEWEB)

    Garg, R. (Roorkee Univ. (India). Dept. of Metallurgical Engineering); Mohan, S. (Banaras Hindu Univ., Varanasi (India). Dept. of Metallurgical Engineering); Agarwala, V. (Roorkee Univ. (India). Dept. of Metallurgical Engineering); Agarwala, R.C. (Roorkee Univ. (India). Dept. of Metallurgical Engineering)

    1993-10-01

    In Al-Pb alloys, boundary lubrication is provided by lead but the matrix with pure aluminium does not provide adequate strength at high loads and high sliding velocities. So in the present investigation an Al-Cu-Si alloy has been taken as the base material and lead has been incorporated by the rheocasting technique. Wear characteristics of the alloy have been investigated at different loads, sliding velocities and sliding distances. Bulk wear has been observed to increase almost linearly with applied load and sliding velocity, but with sliding distance the bulk wear shows a short period of running-in followed by a long steady-state wear. (orig.)

  18. Characteristics and mechanism of abrasive wear for thermoplastic polymers

    Institute of Scientific and Technical Information of China (English)

    Xian Jia; Xiaomei Ling

    2003-01-01

    Abrasive wear characteristics of polyethylene, polystyrene, polymethylmethacrylate, nylon 1010 and polyvinyl chloride were investigated. The volume relative wear resistance coefficients of these thermoplastic polymers are 18%-35 % (hardened and low temperature tempered steel 45 was used as a comparing material), and have a linear correlation with square roots of their cohesive energy densities. The coefficients of linear correlation is 0.949. Wear morphologies were observed by scanning electron microscope (SEM). Main wear mechanism of the thermoplastic polymers includes brittle breaking for the hard and brittle polymers & plowing and fatiguing for the soft and tough ones.

  19. Wear Behavior of an Unstable Knee: Stabilization via Implant Design?

    Directory of Open Access Journals (Sweden)

    Jörn Reinders

    2014-01-01

    Full Text Available Background. Wear-related failures and instabilities are frequent failure mechanisms of total knee replacements. High-conforming designs may provide additional stability for the joint. This study analyzes the effects of a ligamentous insufficiency on the stability and the wear behavior of a high-conforming knee design. Methods. Two simulator wear tests were performed on a high-conforming total knee replacement design. In the first, a ligamentous-stable knee replacement with a sacrificed anterior cruciate ligament was simulated. In the second, a ligamentous-unstable knee with additionally insufficient posterior cruciate ligament and medial collateral ligament was simulated. Wear was determined gravimetrically and wear particles were analyzed. Implant kinematics was recorded during simulation. Results. Significantly higher wear rates (P≤0.001 were observed for the unstable knee (14.58±0.56 mg/106 cycles compared to the stable knee (7.97 ± 0.87 mg/106 cycles. A higher number of wear particles with only small differences in wear particle characteristics were observed. Under unstable knee conditions, kinematics increased significantly for translations and rotations (P≤0.01. This increase was mainly attributed to higher tibial posterior translation and internal rotations. Conclusion. Higher kinematics under unstable test conditions is a result of insufficient stabilization via implant design. Due to the higher kinematics, increased wear was observed in this study.

  20. Wear behaviour of epoxy resin filled with hard powders

    Science.gov (United States)

    Formisano, A.; Boccarusso, L.; Minutolo, F. Capece; Carrino, L.; Durante, M.; Langella, A.

    2016-10-01

    The development of high performance materials based on epoxy resin finds a growing number of applications in which high wear resistance is required. One major drawback in many of these applications is the relatively poor wear resistance of the epoxy resin. Therefore, in order to investigate on the possibility of increasing wear resistance of thermoset polymers filled with hard powders, sliding tests are carried out by means of a pin on disc apparatus. In particular, composite resins, constituted by an epoxy resin filled with different contents and sizes of Silicon Carbide powder, are analyzed; the wear resistance, in terms of volume loss, is measured for different abrasive counterfaces and loads.

  1. Prediction of Cone Crusher Performance Considering Liner Wear

    Directory of Open Access Journals (Sweden)

    Yanjun Ma

    2016-12-01

    Full Text Available Cone crushers are used in the aggregates and mining industries to crush rock material. The pressure on cone crusher liners is the key factor that influences the hydraulic pressure, power draw and liner wear. In order to dynamically analyze and calculate cone crusher performance along with liner wear, a series of experiments are performed to obtain the crushed rock material samples from a crushing plant at different time intervals. In this study, piston die tests are carried out and a model relating compression coefficient, compression ratio and particle size distribution to a corresponding pressure is presented. On this basis, a new wear prediction model is proposed combining the empirical model for predicting liner wear with time parameter. A simple and practical model, based on the wear model and interparticle breakage, is presented for calculating compression ratio of each crushing zone along with liner wear. Furthermore, the size distribution of the product is calculated based on existing size reduction process model. A method of analysis of product size distribution and shape in the crushing process considering liner wear is proposed. Finally, the validity of the wear model is verified via testing. The result shows that there is a significant improvement of the prediction of cone crusher performance considering liner wear as compared to the previous model.

  2. Friction and wear in polymer-based materials

    CERN Document Server

    Bely, V A; Petrokovets, M I

    1982-01-01

    Friction and Wear in Polymer-Based Materials discusses friction and wear problems in polymer-based materials. The book is organized into three parts. The chapters in Part I cover the basic laws of friction and wear in polymer-based materials. Topics covered include frictional interaction during metal-polymer contact and the influence of operating conditions on wear in polymers. The chapters in Part II discuss the structure and frictional properties of polymer-based materials; the mechanism of frictional transfer when a polymer comes into contact with polymers, metals, and other materials; and

  3. Wear Debris Identification Using Feature Extraction and Neural Network

    Institute of Scientific and Technical Information of China (English)

    王伟华; 马艳艳; 殷勇辉; 王成焘

    2004-01-01

    A method and results of identification of wear debris using their morphological features are presented. The color images of wear debris were used as initial data. Each particle was characterized by a set of numerical parameters combined by its shape, color and surface texture features through a computer vision system. Those features were used as input vector of artificial neural network for wear debris identification. A radius basis function (RBF) network based model suitable for wear debris recognition was established,and its algorithm was presented in detail. Compared with traditional recognition methods, the RBF network model is faster in convergence, and higher in accuracy.

  4. Patient comfort following thirty minutes of lens wear: piggy-back versus conventional rigid-lens wear

    Directory of Open Access Journals (Sweden)

    W. D.H. Gillan

    2014-08-01

    Full Text Available Discomfort when wearing contact lenses, especially rigid contact lenses, is a common complaint amongst neophyte as well as experienced contact lens wearers. Wearing a piggy-back system of contact lenses has been shown to improve comfort and wearing time, especially in keratoconic subjects. Twenty two normal subjects wore a rigid lens or a piggy-back system of lenses for thirty minutes and after a thirty minute break swopped the mode of lens wear and wore the second modality for a thirty minute period. This study suggests that a piggy-back lens system provides improved comfort compared to wearing a rigid lens on its own. The order of lens wear might, however, influence the perceived comfort.

  5. A comparative study of sliding wear of nonmetallic dental restorative materials with emphasis on micromechanical wear mechanisms.

    Science.gov (United States)

    Dupriez, Nataliya Deyneka; von Koeckritz, Ann-Kristin; Kunzelmann, Karl-Heinz

    2015-05-01

    The purpose of this study is to investigate the in vitro tribological behavior of modern nonmetallic restorative materials. Specimen prepared of IPS e.max Press lithium disilicate glass ceramic, IPS Empress Esthetic leucite-reinforced glass ceramic, Everest ZS Blanks yttria-stabilized zirconia and Lava Ultimate composite were subjected to wear using a wear machine designed to simulate occlusal loads. The wear of the investigated materials and antagonists were evaluated by a three-dimensional surface scanner. The quantitative wear test results were used to compare and rank the materials. Specimens were divided into two groups with steatite and alumina antagonists. For each antagonist material an analysis of variance was applied. As a post hoc test of the significant differences, Tukey's honest significant difference test was used. With steatite antagonist: wear of zirconia materials mechanical properties (hardness and fracture toughness) and with materials microstructure. Wear mechanisms are discussed. © 2014 Wiley Periodicals, Inc.

  6. The Influence of Soft Contact Lens Wear and Two Weeks Cessation of Lens Wear on Corneal Curvature

    OpenAIRE

    Lloyd McKernan, Aoife; O'Dwyer, Veronica; Simo Mannion, Luisa

    2014-01-01

    Abstract Introduction Accurate corneal measurements are crucial in corneal refractive surgery (CRS) to ensure successful outcomes. Soft contact lens (SCL) wear may result in changes to corneal curvature and structure. United States Food and Drug Administration (FDA) pre-operative guidelines recommend that prior to CRS, SCL wearers cease SCL wear for “at least two weeks before examination and treatment”[1]. Corneal curvature changes induced by SCL wear may take longer than two weeks to reso...

  7. INFLUENCE TOOL WEAR IN MATERIAL FLOW

    Directory of Open Access Journals (Sweden)

    Vladimíra Schindlerová

    2017-03-01

    Full Text Available The cold bulk forming is a technology that is commonly used in many industrial enterprises. Even though nowadays high demands are posed on labour productivity, quality and own production costs, the findings from practice suggests that not sufficient attention is paid to the issue of tool manage-ment. Also, the theoretical backgrounds and knowledge in this area are not processed in a sufficiently detailed and comprehensive way. This paper submitted to conference deals with the issue of predic-tion of the wear surface of the forming tools and their subsequent renewal. The research at selected materials was focused on the course of their straining in contact of the blank with the tool in the process of cold bulk forming. The experiments were based on a simple performance of the conven-tional upsetting test. On the basis of analysis of the results was determined the mechanism of tool wear by abrasion and was evaluated its impact on the service life time of the tool and also the possi-bility of influencing the quality of final parts.

  8. Anisotropic mechanical amorphization drives wear in diamond.

    Science.gov (United States)

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond's widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp(3)-sp(2) order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  9. "Work smart, wear your hard hat"

    CERN Multimedia

    2003-01-01

    Falling objects and collisions are frequent occurrences in work sites and hazardous areas. Hard hats can help prevent many types of accident and can even save lives. Just imagine an 800 g spanner falling from a 13 m high scaffold onto the head of someone standing below - a nightmare scenario! The impact to the head is equivalent to that of a 5 kg weight falling from 2 metres. That is just what happened to Gerd Fetchenhauer when he was working on the UA1 experiment. Fortunately, he was wearing a hard hat at the time. "That hat saved my life," he explains. "It punched a hole right through the hat and I was a bit dazed for a couple of hours but otherwise I was OK." Since that day, Gerd Fetchenhauer, now working on CMS, is never seen on a work site without his hard hat on. Work sites have proliferated at CERN with the construction of the LHC and its detectors, and the wearing of hard hats is compulsory (not to mention life-saving). In the underground caverns and experiment halls, where gantry cranes and other h...

  10. Patient comfort following thirty minutes of lens wear: piggy-back versus conventional rigid-lens wear

    OpenAIRE

    W.D.H. Gillan

    2014-01-01

    Discomfort when wearing contact lenses, especially rigid contact lenses, is a common complaint amongst neophyte as well as experienced contact lens wearers. Wearing a piggy-back system of contact lenses has been shown to improve comfort and wearing time, especially in keratoconic subjects. Twenty two normal subjects wore a rigid lens or a piggy-back system of lenses for thirty minutes and after a thirty minute break swopped the mode of lens wear and wore the second modality for a thirty minut...

  11. The action and analysis of magnetic field on the lubricants and wear products in the process of wearing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The magnetic field is an important factor in the conditioning and controlling tribologicalproperty. This paper analyzes and describes the physical effects and chemical natures of magneticfield to affect the friction, wear and lubrication, and characterize the tribochemical effect of mag-netic field on WRL lubricant by infrared(IR) spectrum method. At same time, the tribological prop-erty of WRL lubricant was examined by using the reciprocating friction-wear tester of NG-x type inthe condition of magnetic field. The results show that the present of magnetic field can decreasethe friction coefficient(f) and wear weight(W), even realize the zero-wear testing situation.

  12. Microstructure, Impact Fatigue Resistance and Impact Wear Resistance of Wear Resistant Low Cr-Si Cast Iron

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A great amount of iron and steel has been consumed in impact wear resistance parts such as grinding balls and lining plates in tube mills. Under this working conditions, the failure of wear resistant white irons is generally caused by fatigue spalling. The martensitic high chromium cast iron (WCr=15 %) has good wear resistance, but its cost is higher. The impact wear resistance of low chromium cast iron sometimes is not good. In the present paper ,a new wear resistant material-low Cr-Si cast iron was introduced. The influence of microstructure of cast iron on impact fatigue resistance and impact wear resistance was discussed. The ball-on-ball impact fatigue test, the high stress impact wear test and the field test of the grinding balls have been carried out. The results showed that the impact fatigue resistance (IFR) and impact wear resistance (IWR) of low Cr-Si cast iron are superior to typical low chromium cast irons and close to the martensitic high chromium cast iron. The main reasons are: ① The as-cast matrix of the low Cr-Si cast iron with stress released is pearlite with better plasticity and toughness; ② The high Si content improves the morphology of eutectic carbide, and has no secondary carbide resulting in less crack sources. All these factors are beneficial to the improvement of impact fatigue spalling resistance and impact wear resistance.

  13. Description to wear debris boundaries by radar graph fractal method

    Institute of Scientific and Technical Information of China (English)

    LIU HongTao; GE ShiRong

    2007-01-01

    In this paper, radar graph fractal method is introduced to describe wear debris boundaries.Research results show that it is a nice way to describe wear debris boundaries.Since the longest axis is selected as the first coordinate axis, its center point selected as the center point of the radar graph, and the coordinate value of wear debris boundary selected as the measure parameter, the limitations existing in Yard fractal measure method can be avoided.For any wear debris, its radar graph fractal dimension value is one and only, and as the wear debris shape changes from round to strip, the radar graph fractal dimension value also changes from low to high, showing strong uniqueness and independence.Due to the fact that the researched wear debris is gotten in different wear states, the results also prove that radar graph fractal dimension value is correlated with frictional pairs work condition and wear state.Radar graph fractal method is compared with Yard fractal measure methods, and results show that radar graph fractal dimension values gotten from different wear debris have enough value grads to avoid effect of errors, and provide higher sensitivity for wear debris shape.This paper also discusses the influencing factors for radar graph fractal method.With the increase of the decomposing degree value, the radar graph fractal dimension tends to keep stable at one certain value, showing the typical characteristic of the fractal theory.All this proves that radar graph fractal method is an effective description method for wear debris boundaries.

  14. 46 CFR 185.508 - Wearing of life jackets.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Wearing of life jackets. 185.508 Section 185.508... TONS) OPERATIONS Preparations for Emergencies § 185.508 Wearing of life jackets. (a) The master of a vessel shall require passengers to don life jackets when possible hazardous conditions exist, including...

  15. 46 CFR 122.508 - Wearing of life jackets.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Wearing of life jackets. 122.508 Section 122.508... Preparations for Emergencies § 122.508 Wearing of life jackets. (a) The master of a vessel shall require passengers to don life jackets when possible hazardous conditions exist, including, but not limited to: (1...

  16. Wear Consideration in Gear Design for Space Applications

    Science.gov (United States)

    1989-01-01

    profile. The Archard 1/2 wear equation ( Rabinowicz , 1965) will be used to calcu- late depth wear (h) as follows b " ’ (5) h= (2) 3pAa where where =rltv aiso...Subtract 0.0018 in. for initial backlash plus Handbook, ASME, New York. tooth-to-tooth composite error (when new) to get Rabinowicz , E., 1965, Friction and

  17. Occlusal wear of provisional implant-supported restorations

    NARCIS (Netherlands)

    Santing, Hendrik J.; Kleverlaan, Cornelis J.; Werner, Arie; Feilzer, Albert J.; Raghoebar, Gerry M.; Meijer, Henny J. A.

    BACKGROUND: Implant-supported provisional restorations should be resistant to occlusal wear. PURPOSE: The purpose of this laboratory study was to evaluate three-body wear of three indirect laboratory composite resins, five chair side bis-acryl resin-based materials, and two chair side

  18. The Prevalence of Tooth Wear in the Dutch Adult Population

    NARCIS (Netherlands)

    Wetselaar, Peter; Vermaire, Jan H; Visscher, Corine M; Lobbezoo, Frank; Schuller, Annemarie A

    2016-01-01

    This study aimed to assess the prevalence of tooth wear in different age groups of the Dutch adult population and to determine this tooth wear distribution by gender, socioeconomic class, and type of teeth. Results were compared with the outcomes of a previous study in a comparable population. As pa

  19. In vitro wear of flowable resin composite for posterior restorations.

    Science.gov (United States)

    Shinkai, Koichi; Taira, Yoshihisa; Suzuki, Shiro; Suzuki, Masaya

    2016-01-01

    The purpose of this study was to examine three- and two-body wear values of flowable resin composites for posterior restorations, using a mechanical loading device. The cavities prepared on flattened extracted molars were restored with flowable resin composites (Clearfil Majesty LV: MLV, Estelite Flow Quick: EFQ, Beautifil Flow Plus F00: BFP, and MI Fill: MIF) using accompanying adhesive systems. A universal resin composite (Clearfil Majesty) was used as a control. The specimens were subjected to in vitro three- and two-body wear testing. MLV showed high wear value (three-body: 14.69 µm, two-body: 0.268 mm(3)) compared with other materials tested in both three- and two-body wear tests. BFP showed high three-body wear value (5.78 µm), whereas low two-body wear value (0.008 mm(3)). MIF and EFQ showed equivalent wear values (MIF, three-body: 0.42 µm, two-body: 0.026 mm(3); EFQ, three-body: 1.15 µm, two-body: 0.14 mm(3)) to that of the control in both wear tests.

  20. Research on Wear Behavior of ATC Cermet Material

    Institute of Scientific and Technical Information of China (English)

    ZHULiu; LINGGuo-ping; LIJian; WANGYou-wen

    2004-01-01

    By electroless chemical deposition process, a layer of metal cobalt film was coated on the surface of nano-ceramic powders of Al2O3 and TiC. The mixture of the two kinds of Co-coated power (about 70wt.% Al2O3-Co+30wt.%TiC-Co) was hot-pressed into ATC (Al2O3-TiC-Co8wt% ) cermet samples. The wear test was carried out under dry sliding wear condition by the pin-on-disk rig. The volume-loss of the samples in three sliding pairs, ATC/Steel, ATC/SiC and ATC/artificial diamond (AD) were investigated. The wear morphologies were examined by SEM. The wear-resistance between ATC cermet and Co-cemented WC were compared. The results show that the effect of fracture toughness is better than that of hardness to the wear resistance of high hardness materials. The wear mechanisms of ATC cermet samples were found that abrasion predominated in the wear process. The wear surface of ATC cermet samples became smoother with fine asperities spalling off and the volume loss was decreased.

  1. Research on Wear Behavior of ATC Cermet Material

    Institute of Scientific and Technical Information of China (English)

    ZHU Liu; LING Guo-ping; LI Jian; WANG You-wen

    2004-01-01

    By electroless chemical deposition process, a layer of metal cobalt film was coated on the surface of nano-ceramic powders of Al203 and TiC. The mixture of the two kinds of Co-coated power (about 70wt.%Al2O3-Co+30wt.%TiC-Co) was hot-pressed into ATC (Al2O3-TiC-Co8wt%) cermet samples. The wear test was carried out under dry sliding wear condition by the pin-on-disk rig. The volume-loss of the samples in three sliding pairs,ATC/Steel, ATC/SiC and ATC/artificial diamond (AD) were investigated. The wear morphologies were examined by SEM.The wear-resistance between ATC cermet and Co-cemented WC were compared. The results show that the effect of fracture toughness is better than that of hardness to the wear resistance of high hardness materials. The wear mechanisms of ATC cermet samples were found that abrasion predominated in the wear process. The wear surface of ATC cermet samples became smoother with fine asperities spalling off and the volume loss was decreased.

  2. Microstructural aspects and wear behavior of sinter hardened distaloy HP

    Energy Technology Data Exchange (ETDEWEB)

    Sheikhi Moghaddam, K.; Ghambari, M.; Farhangi, H. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran (Iran, Islamic Republic of); Solimanjad, N.; Bergmark, A. [Hoeganaes AB, Bruksgatan, Hoeganaes (Sweden); Khorsand, H. [K.N. Toosi University, Tehran (Iran, Islamic Republic of)

    2011-11-15

    Effect of cooling rate during sinter hardening on the microstructure and wear behavior of sintered steel grade Distaloy HP has been studied. Wear performances are closely related to macro and micro hardness of the materials. Dry sliding wear tests have been conducted using a reciprocating pin on flat wear testing machine under normal loads of 25, 35 and 45N and at a constant speed of 0.3 m/s. The samples were sinter hardened at different cooling rates 0.5-3 C/s in order to investigate the influence of microstructure and hardness on wear behavior. It has been shown that, sintering process and cooling rate change the microstructure and hence the hardness and wear behavior of the material. The best wear resistance was detected at a cooling rate of 3 C/s. At this cooling rate the material had an almost martensitic microstructure and the wear rate was some how independent of the applied load. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Wear numbers for ball cup and journal bearings

    NARCIS (Netherlands)

    Ligterink, D.J.; Moes, H.

    1980-01-01

    A wear number is defined for ball cup bearings and for journal bearings where the cup and the cylindrical bearing are made of soft material. This dimensionless wear number provides a relation between the following five quantities: the radius of the ball or the length of the journal bearing in millim

  4. Nanoscale wear as a stress-assisted chemical reaction.

    Science.gov (United States)

    Jacobs, Tevis D B; Carpick, Robert W

    2013-02-01

    Wear of sliding contacts leads to energy dissipation and device failure, resulting in massive economic and environmental costs. Typically, wear phenomena are described empirically, because physical and chemical interactions at sliding interfaces are not fully understood at any length scale. Fundamental insights from individual nanoscale contacts are crucial for understanding wear at larger length scales, and to enable reliable nanoscale devices, manufacturing and microscopy. Observable nanoscale wear mechanisms include fracture and plastic deformation, but recent experiments and models propose another mechanism: wear via atom-by-atom removal ('atomic attrition'), which can be modelled using stress-assisted chemical reaction kinetics. Experimental evidence for this has so far been inferential. Here, we quantitatively measure the wear of silicon--a material relevant to small-scale devices--using in situ transmission electron microscopy. We resolve worn volumes as small as 25 ± 5 nm(3), a factor of 10(3) lower than is achievable using alternative techniques. Wear of silicon against diamond is consistent with atomic attrition, and inconsistent with fracture or plastic deformation, as shown using direct imaging. The rate of atom removal depends exponentially on stress in the contact, as predicted by chemical rate kinetics. Measured activation parameters are consistent with an atom-by-atom process. These results, by direct observation, establish atomic attrition as the primary wear mechanism of silicon in vacuum at low loads.

  5. Comparative Study of Wear Resistance of Sewing Needles

    Institute of Scientific and Technical Information of China (English)

    FEI Dong-ye; ZHU Shi-gen

    2002-01-01

    Poor wearability is the most serious problem of domestic sewing needle, which is the main reason for their short service lives. The influences of needle materials,microstructures and manufacturing technologies on the wear resistance are analyzed in comparison with foreign sewing needles. A series of suitable measures are proposed to improve the wear resistance.

  6. The transition of mild to severe wear of ceramics

    NARCIS (Netherlands)

    Pasaribu, H.R.; Sloetjes, J.W.; Schipper, D.J.

    2004-01-01

    The transition of mild to severe wear of ceramics depends on the operating conditions (normal load, velocity and temperature) and material properties (like grain size, mechanical and thermal material properties). Adachi et al. [Wear 203¿204 (1997) 291] introduced the transition of mild to severe wea

  7. A Finite Element Approach to Modeling Abrasive Wear Modes

    NARCIS (Netherlands)

    Woldman, M.; Heide, van der E.; Tinga, T.; Masen, M.A.

    2016-01-01

    Machine components operating in sandy environments will wear because of the abrasive interaction with sand particles. In this work, a method is derived to predict the amount of wear caused by such abrasive action, in order to improve the maintenance concept of the components. A finite element model

  8. Scanning-electron-microscope used in real-time study of friction and wear

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Small friction and wear apparatus built directly into scanning-electron-microscope provides both dynamic observation and microscopic view of wear process. Friction and wear tests conducted using this system have indicated that considerable information can readily be gained.

  9. Optimization of Process Parameters of Tool Wear in Turning Operation

    Directory of Open Access Journals (Sweden)

    Manik Barman

    2015-04-01

    Full Text Available Tool Wear is of great apprehension in machining industries since itaffects the surface quality, dimensional accuracy and production cost of the materials / components. In the present study twenty seven experiments were conducted as per 3 parameter 3 level full factorial design for turning operation of a mild steel specimen with high speed steel (HSS cutting tool. An experimental investigation on cutting tool wear and a mathematical model for tool wear estimation is reported in this paper where the model was simulated by computer programming and it has been found that this model is capable of estimating the wear rate of cutting tool and it provides an optimum set of process parameters for minimum tool wear.

  10. Enhanced DLC wear performance by the presence of lubricant additives

    Directory of Open Access Journals (Sweden)

    Romina Paula de Castro Costa

    2011-01-01

    Full Text Available Lubricant additives play significant role for reducing friction and wear of mechanical elements. The additives presented in 5W30 oil were developed for metal surfaces. However, they have been used in engine pieces covered with DLC coatings because they also offer the potential to reduce friction losses and wear in automotive applications. The friction and wear tests were carried out by using a UMT-CETR ball-on-disk tribometer in rotational mode under 5W30 synthetic oil at 100 °C. The X-ray photoelectron spectroscopy (XPS showed the presence of Mo and S in the wear tracks. These elements are from decomposition of ZDDP and MoDTC additives producing MoS2 in DLC surface, which offers enhanced durability by low wear rate.

  11. WEAR AND SEALING CHARACTERISTICS OF ENGINE VALVE GUIDE

    Institute of Scientific and Technical Information of China (English)

    Qu Shengguan; Xia Wei; Han Lifa; Xiao Zhiyu; Chen Weiping; Li Yuanyuan

    2005-01-01

    A novel powder metallurgy (P/M) material with high wear resistance is developed in order to decrease the wear and lubricant-leakage of a diesel engine valve guide. The friction and wear tests of this material are conducted. It indicates that the wear resistance of the newly developed P/M material has been improved and much better than that of the formerly used alloy steel. Moreover, three different sealing structures are designed and theoretically analyzed with respect to the characteristic of hydrodynamic sealing. Through comparative experiments of component leakage and engine run-in for different valve guide structures, it proves that the structure with a machined sealing groove but not installed with a seal-ring cannot only reduce the specific lubricant consumption (SLC) of cylinder head, but also decrease the wear of valve stem and valve guide.

  12. Quasi-nano wear mechanism under repeated impact contact loading

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new quasi-nano wear mechanism (QNWM) has been proposed in this paper based on the facts of wear curve turning under high energy impact contact loading.Its characteristic is that the wear rate of QNWM is only 1/10-1/3 that of delamination mechanism at the same energy density.The diameters of wear debris and pits on the worn surfaces fall into the quasi-nanometer scale (about 50-120 nm).The necessary and sufficient conditions,which bring about the QNWM,are:(i) the nano-structure (nano-crystalline + amorphous phase) in impact contact surface layer has formed by the intensive impact strain;(ii) the delamination wear cracking in sub-surface layer must be restrained;(iii) the microcracks of QNWM are produced in amorphous phase of surface nano-structure layer rather than in nano-crystalline.

  13. Factors affecting enamel and ceramic wear: a literature review.

    Science.gov (United States)

    Oh, Won-Suck; Delong, Ralph; Anusavice, Kenneth J

    2002-04-01

    Enamel wear by ceramics may adversely affect maintenance of the vertical dimension of occlusion and can increase the potential for thermal sensitivity. In this article, factors related to the abrasion of enamel by dental ceramics are critically reviewed. Concepts of physical, microstructural, chemical, and surface characteristics of dental ceramics on wear are presented based on research published since 1950. A PubMed search for key words (wear of enamel and ceramic) was supplemented with a hand search to identify relevant peer-reviewed articles published in English. Based on the literature, it can be concluded that material factors, their proper handling, and control of the patient's intrinsic risk factors related to wear are critically important to the reduction of enamel wear by dental ceramics.

  14. Nitrocarburizing for wear, corrosion, and fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, G. [Durferrit GmbH Thermotechnik, Hanau (Germany)

    1996-04-01

    Demands for higher strength and corrosion resistance at higher temperatures cannot always be met by advanced materials and designs alone. In many cases, surface engineering can provide required properties and extend service life. A thermochemical surface engineering treatment has been developed that improves the dynamic strength of parts and overcomes many corrosion and wear problems. Known as Melonite, the process was developed by Durferrite GmbH Thermotechnik, and is used to enhance the surface properties of steel and iron parts. The quench, quench-polish, and quench-polish-quench salt bath nitrocarburizing system can provide surface layers with a range of beneficial properties. This article will discuss details of the Melonite process, component properties after treatment, the effects of raising or lowering treatment temperatures, and environmental impact.

  15. Standard Terminology Relating to Wear and Erosion

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 The terms and their definitions given herein represent terminology relating to wear and erosion of solid bodies due to mechanical interactions such as occur with cavitation, impingement by liquid jets or drops or by solid particles, or relative motion against contacting solid surfaces or fluids. This scope interfaces with but generally excludes those processes where material loss is wholly or principally due to chemical action and other related technical fields as, for instance, lubrication. 1.2 This terminology is not exhaustive; the absence of any particular term from this collection does not necessarily imply that its use within this scope is discouraged. However, the terms given herein are the recommended terms for the concepts they represent unless otherwise noted. 1.3 Certain general terms and definitions may be restricted and interpreted, if necessary, to make them particularly applicable to the scope as defined herein. 1.4 The purpose of this terminology is to encourage uniformity and accuracy ...

  16. Fatigue, Wear and Cracking of Dental Materials

    Directory of Open Access Journals (Sweden)

    Traian Eugen Bolfa

    2015-07-01

    Full Text Available Evaluation of the method of failure and crack propagation in dental metals, ceramics and polymer composite materials associated with occlusal activity are associated with contact, twisting and sliding modes. Such loads can result in various combinations of damage due to fatigue and wear. In order to increase sustainability and longevity the dental materials must demonstrate sufficient strength to dynamic stresses. In the case of masticatory forces associated with high contact tensions, the contact area of the superficial layer is under a state of specialcomplex voltage. Variations in the material or the structure, impurities, scratches and voids can directly influence the structural integrity of the material and result in microscopic cracks. These cracks propagate under repeated cyclic loading leading to dental restoration failure.

  17. "Teaching students how to wear their Computer"

    DEFF Research Database (Denmark)

    Guglielmi, Michel; Johannesen, Hanne Louise

    2005-01-01

    to address this question trough the angle of what we called ‘Physical Computing’ and asked ourselves and the students if new fields like ‘tangible media’ or ‘wearable computers’ can contribute to improvements of life? And whose life improvement are we aiming for? Computers are a ubiquitous part...... the mobility but the operationability is still obtained through screens and buttons and as something to wear it is still not integrated with everyday use and comfort as clothes. A wearable computer should be worn, much like eyeglasses or clothing and interact with the user based on the context of the situation...... prototyping’ and prototypes based on advanced sensor technology (Pressure sensors) and other devices like E-ink. Not in order to develop gadget but to develop systems able to support HHI. The final output for the competition was a 3 minutes video presenting the core ideas of the project as well...

  18. Effect of filler size on wear resistance of resin cement.

    Science.gov (United States)

    Shinkai, K; Suzuki, S; Katoh, Y

    2001-11-01

    The purpose of this study was to evaluate the effect of filler size on the wear of resin cements. Materials tested included four experimental dual-cure resin cements (Kuraray) consisting of different-sized filler particles. A rectangular box cavity was prepared on the flattened occlusal surface of extracted human molars. Ceramic inlays for the cavities were fabricated using the Cerec 2 system. The Cerec inlays were cemented with the respective cements and adhesive systems according to the manufacturer's directions. The restored surface was finished by wet-grinding with an 800-grit silicon carbide paper. Six specimens were prepared for each resin cement. Half of the specimens were subjected to a three-body wear test for 200,000 cycles, and the others were subjected to a toothbrush abrasion test for 30,000 cycles. The worn surface of each restoration was scanned by a profilometer (Surfcom 475 A) at eight different points for each restoration. The wear value was determined by measuring the vertical gap depth on the profilometric tracings. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Scheffe's test. The results showed that, with increase of filler size, the wear value decreased in the toothbrush test and increased in the three-body wear test. The cement with 0.04-microm filler exhibited the lowest wear value among the materials in the three-body wear test, and the same wear value as the cement with 0.97-microm filler in the toothbrush test. Based upon the results of this study, it is concluded that the wear of resin cements was affected by the filler size as well as the mode of wear test.

  19. Friction and wear behaviour of self lubricating bearing liners

    Science.gov (United States)

    Gay, Russell

    The thesis describes a numerical model for evaluating the variation of friction and wear of a self lubricating bearing liner over its useful wear life. Self-lubricating bearings have been in widespread use since the mid-1950s, particularly in the aerospace industry where they have the advantage of being low maintenance components. They are commonly used in relatively low speed, reciprocating applications such as control surface actuators, and usually consist of a spherical bearing with the inner and outer elements separated by a composite textile resin-bonded liner. A finite element model has been developed to predict the local stiffness of a particular liner at different states of wear. Results obtained using the model were used to predict the overall friction coefficient as it evolves due to wear, which is a novel approach. Experimental testing was performed on a bespoke flat-on-flat wear test rig with a reciprocating motion to validate the results of the friction model.. These tests were carried out on a commercially-available bearing liner, predominantly at a high contact pressure and an average sliding speed of 0.2 ms-1. Good agreement between predicted and experimentally measured wear was obtained when appropriate coefficients of friction were used in the friction model, and when the reciprocating sliding distance was above a critical value. A numerical wear model was also developed to predict the trend of backlash development in real bearing geometries using a novel approach. Results from the wear model were validated against full-scale bearing tests carried out elsewhere by the sponsoring company. Good agreement was obtained between the model predictions and the experimental results for the first 80% of the bearing wear life, and explanations for the discrepancy during the last 20% of the wear life have been proposed..

  20. Dry wear behaviors of wear resistant composite coatings produced by laser cladding

    Institute of Scientific and Technical Information of China (English)

    Jiang Xu; Wenjin Liu; Minlin Zhong

    2004-01-01

    Using different proportional mixtures of Ni-coated MoS2, TiC and pure Ni powders, new typical wear resistant and selflubricant coatings were formed on low carbon steel by laser cladding process. The microstructures and phase composition of the composite coatings were studied by SEM and XRD. The typical microstructure of the composite coating is composed of multisulfide phases including binary element sulfide and ternary element sulfide, γ-Ni, TiC and Mo2C. Wear tests were carried out using an FALEX-6 type pin-on-disc machine. The friction coefficient and mass loss of three kinds of MoS2/TiC/Ni laser clad coatings are lower than those of quenched 45 steel, and the worn surfaces of the laser cladding coatings are very smooth. Because of high hardness combined with low friction, the laser cladding composite coating with a mixture of 70% Ni-coated MoS2, 20%TiC and 10%pure Ni powder presents better wear behaviors than the composite coating with other powder blends. The composition analysis of the worn surface of GCr15 bearing steel shows that the transferred film from the laser cladding coating to the opposite surface of GCr15beating steel contains an amount of sulfide, which can change the micro-friction mechanism and lead to a reduced friction coefficient.

  1. Role of PET in improving wear properties of PP in dry sliding condition

    Indian Academy of Sciences (India)

    Somit Neogi; S A R Hashmi; Navin Chand

    2003-10-01

    The sliding wear of isotactic polypropylene (PP), polyethylene terephthalate (PET) and their blends was evaluated as a function of applied pressure and composition against a stainless steel counter face in dry condition. Wear rate decreases with the addition of PET in the blend. The wear was observed in two stages, the moderate wear and high wear while increasing the applied pressure on test samples. The addition of PET in PP helps in increasing the limit of moderate wear towards the high-pressure side. Microstructure and worn surfaces of samples were observed by scanning electron microscope. The wear phenomenon has been discussed based on wear losses and worn surfaces.

  2. Numerical simulation of wheel wear evolution for heavy haul railway

    Institute of Scientific and Technical Information of China (English)

    王璞; 高亮

    2015-01-01

    The prediction of the wheel wear is a fundamental problem in heavy haul railway. A numerical methodology is introduced to simulate the wheel wear evolution of heavy haul freight car. The methodology includes the spatial coupling dynamics of vehicle and track, the three-dimensional rolling contact analysis of wheel-rail, the Specht’s material wear model, and the strategy for reproducing the actual operation conditions of railway. The freight vehicle is treated as a full 3D rigid multi-body model. Every component is built detailedly and various contact interactions between parts are accurately simulated, taking into account the real clearances. The wheel−rail rolling contact calculation is carried out based on Hertz’s theory and Kalker’s FASTSIM algorithm. The track model is built based on field measurements. The material loss due to wear is evaluated according to the Specht’s model in which the wear coefficient varies with the wear intensity. In order to exactly reproduce the actual operating conditions of railway, dynamic simulations are performed separately for all possible track conditions and running velocities in each iterative step. Dimensionless weight coefficients are introduced that determine the ratios of different cases and are obtained through site survey. For the wheel profile updating, an adaptive step strategy based on the wear depth is introduced, which can effectively improve the reliability and stability of numerical calculation. At last, the wear evolution laws are studied by the numerical model for different wheels of heavy haul freight vehicle running in curves. The results show that the wear of the front wheelset is more serious than that of the rear wheelset for one bogie, and the difference is more obvious for the outer wheels. The wear of the outer wheels is severer than that of the inner wheels. The wear of outer wheels mainly distributes near the flange and the root;while the wear of inner wheels mainly distributes around the

  3. The biochemical characteristics of wear testing lubricants affect polyethylene wear in orthopaedic pin-on-disc testing.

    Science.gov (United States)

    Guenther, Leah E; Turgeon, Thomas R; Bohm, Eric R; Brandt, Jan-M

    2015-01-01

    Lubricant protein concentration is known to affect crosslinked polyethylene wear in in vitro testing; however, the biochemical nature of these lubricants may also have a significant effect on wear and dictate its clinical relevance. A modified approach to pin-on-disc testing was implemented to explore the effect of four biochemically different lubricants on the wear of two types of crosslinked polyethylene materials (XLK™ and Marathon™; DePuy Synthes, Warsaw, IN, USA). XLK was associated with higher wear rates than Marathon. In comparison to lubricants containing deionized water, lubricants containing phosphate buffered saline solution and hyaluronic acid increased osmolality by up to 1.2 times and thermal stability by up to 1.4 times. This biochemical change reduced wear by up to 12.5 times. Wear rates for XLK and Marathon differed by a factor of 3.2 using lubricants with phosphate buffered saline solution as the dilutive media, but only 2.0 for lubricants with deionized water. Interestingly, varying the concentration of hyaluronic acid did not have a significant effect on wear, and differences between XLK and Marathon wear rates were not found to be statistically significant when hyaluronic acid was added to the lubricant. The findings of this study showed that increasing the osmolality and thermal stability of lubricants to more clinical levels decreased wear; however, the effect of hyaluronic acid on wear may not be apparent in simplistic pin-on-disc testing. It was suggested that phosphate buffered saline solution be used as the dilutive media of choice in order to better differentiate the ranking of materials while maintaining some clinical relevance.

  4. Interaction of sulfuric acid corrosion and mechanical wear of iron

    Science.gov (United States)

    Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

    1986-01-01

    Friction and wear experiment were conducted with elemental iron sliding on aluminum oxide in aerated sulfuric acid at concentrations ranging from very dilute (0.00007 N; i.e., 4 ppm) to very concentrated (96 percent acid). Load and reciprocating sliding speed were kept constant. With the most dilute acid concentration of 0.00007 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At slightly higher concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent (1 N), the well-established high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid and decreased somewhat to 50 percent acid in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It was apparent that the normal passivating film was being worn away and a galvanic cell established that rapidly attacked the wear area. Under the conditions where direct corrosion losses were highest, the coefficient of friction was the lowest.

  5. Wear resistance of TiAlSiN thin coatings.

    Science.gov (United States)

    Silva, F J G; Martinho, R P; Alexandre, R J D; Baptista, A P M

    2012-12-01

    In the last decades TiAIN coatings deposited by PVD techniques have been extensively investigated but, nowadays, their potential development for tribological applications is relatively low. However, new coatings are emerging based on them, trying to improve wear behavior. TiAlSiN thin coatings are now investigated, analyzing if Si introduction increases the wear resistance of PVD films. Attending to the application, several wear test configurations has been recently used by some researchers. In this work, TiAISiN thin coatings were produced by PVD Unbalanced Magnetron Sputtering technique and they were conveniently characterized using Scanning Electron Microscopy (SEM) provided with Energy Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), Electron Probe Micro-Analyzer (EPMA), Micro Hardness (MH) and Scratch Test Analysis. Properties as morphology, thickness, roughness, chemical composition and structure, hardness and film adhesion to the substrate were investigated. Concerning to wear characterization, two very different ways were chosen: micro-abrasion with ball-on-flat configuration and industrial non-standardized tests based on samples inserted in a feed channel of a selected plastic injection mould working with 30% (wt.) glass fiber reinforced polypropylene. TiAISiN coatings with a small amount of about 5% (wt.) Si showed a similar wear behavior when compared with TiAIN reported performances, denoting that Si addition does not improve the wear performance of the TiAIN coatings in these wear test conditions.

  6. Influence of Fretting Wear on Lifetime of Tin Plated Connectors

    Science.gov (United States)

    Ikeda, Hirosaka; Ito, Tetsuya; Sawada, Shigeru; Hattori, Yasuhiro; Saitoh, Yasushi; Tamai, Terutaka; Iida, Kazuo

    Due to the recent increase in electronic devices mounted on automobiles, a large number of connectors, especially low-cost tin plated connectors are being used. As a result, their contact reliability has become problematic. Furthermore, for the connectors which are subjected to fretting wear caused by heat cycle and vibrations, the contact resistance increases because of wear of tin and deposition of oxides, which generates problems of poor contact. This study is intended to analyze the change in contact resistance of tin plated connectors from the start of fretting wear to the end of their lifetime from the viewpoint of practical reliability, and to observe the trace and the characteristics of fretting wear microscopically. This study found that wear and oxidation of tin plated connectors start immediately with fretting wear, and thus accumulation of abrasion powder on fretting areas causes connectors to reach to the end of their useful lifetime quickly. Especially, it was demonstrated that amplitude of fretting has a considerable influence on a connector's lifetime. It is made clear that air-tightness, so-called “gas-tight” of tin in a fretting area influences fretting wear considerably.

  7. Enamel erosion and mechanical tooth wear in medieval Icelanders.

    Science.gov (United States)

    Richter, Svend; Eliasson, Sigfus Thor

    2016-01-01

    The Icelandic Sagas are an important source of information on the way of life and diet habits in Iceland and possibly other Nordic countries 1000 years ago. Archaeological human skull material worldwide has revealed extensive tooth wear, with the main cause believed to be coarse diet. From a graveyard near volcano Hekla, 66 skeletons dated from before 1104 were excavated. The purpose of this study was to determine the main causes of tooth wear in Icelanders 1000 years ago. Forty-nine skulls were available for research. Two methods were used to evaluate tooth wear and seven for age estimation. An attempt was made to determine the main causes of tooth wear in the light of likely diet and beverage consumption according to a computer search on food and drink customs described in the Icelandic Sagas. Tooth wear was extensive in all groups, increasing with age. The highest score was on first molars, with no difference between sexes. It had all the similarities seen in wear from coarse diet. In some instances it had similar characteristics to those seen in erosion in modern Icelanders consuming excessive amounts of soft drinks. According to the Sagas, acidic whey was a daily drink and used for preservation of food in Iceland until recently. Since acidic whey has considerably high dental erosive potential, it is postulated that consumption of acidic drinks and food, in addition to a coarse and rough diet, played a significant role in the dental wear of ancient Icelanders.

  8. Clinical assessment of enamel wear caused by monolithic zirconia crowns.

    Science.gov (United States)

    Stober, T; Bermejo, J L; Schwindling, F S; Schmitter, M

    2016-08-01

    The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6-, 12-, and 24-month follow-up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser-scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two-sided paired Student's t-tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19-26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75-115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia-opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified.

  9. The wear of two orthopaedic biopolymers against each other.

    Science.gov (United States)

    Joyce, T J

    2005-01-01

    The potential for all-polymer prostheses has not been widely investigated. It might be expected that the wear of such biomaterial combinations would be excessive, but an in vivo study of all polymer knee prostheses reported that there were no failures due to wear, even after ten years of clinical use. This design of knee prosthesis used polyacetal and ultra high molecular weight polyethylene (UHMWPE) as the biopolymers. Similarly, an earlier in vitro study of polyacetal and UHMWPE hip prostheses indicated lower wear than for a cobalt chrome and UHMWPE combination. Therefore this study set out to test the poly-acetal and UHMWPE combination in a wear screening rig which had previously been validated against clinical data for artificial hip joints. Two different motion conditions were applied to the test samples and each biopolymer was tested as both pin and plate. Interestingly it was found that, whatever the contribution from pin or plate, the total mean wear factors were 1.5 10 -6 mm 3/Nm under reciprocation-only, and 4.1 10 -6 mm 3 /Nm under multi-directional motion. These wear factors were greater than those found when a conventional metal-on-UHMWPE couple was tested under the same loading, motion and lu-bricant conditions. A comparison was also undertaken with the wear of other orthopaedic biopolymer combinations, namely cross-linked polyethylene (XLPE) against itself, and UHMWPE against itself. The XLPE pairing showed somewhat lower wear than the polyacetal and UHMWPE couple, while the UHMWPE pairing showed the highest wear of all, approximately an or-der of magnitude greater than the polyacetal and UHMWPE combination.

  10. Lubricity Additives and Wear with DME in Diesel Injection Pumps

    DEFF Research Database (Denmark)

    Nielsen, Kasper; Sorenson, Spencer C.

    1999-01-01

    In recent years it has been demonstrated that Dimethyl Ether (DME) possess many characteristics that could make it a successful alternative to diesel in the next century. High wear of the fuel injection system has been reported. This is caused by lack of natural protective constituents of Dimethyl...... wear of standard diesel jerk pump plungers elements were made with weight measurements, diameter measurements, 2-D and 3-D surface roughness measurements, and photography by a Michelson interferometer. Several lubricity additives were tested, but none reduced wear levels to those for diesel fuel...

  11. Use of GPR technique in surveying gravel road wearing course

    Science.gov (United States)

    Saarenketo, Timo; Vesa, Heikki

    2000-04-01

    During summer 1998 a series of tests were conducted in Finland in order to find out how Ground Penetrating Radar (GPR) technology can be utilized at both the project and network level, when surveying the wearing course thickness of gravel roads. The second objective was to investigate the possibilities of applying dielectricity information obtained using the GPR surface reflection method when determining the quality of the gravel road wearing course. In this study GPR was tested at the project level on highway 9241 Simo in Northern Finland, where the information provided by the GPR and laboratory research was used in designing and proportioning a new wearing course. In the network level studies, performed in the maintenance areas of Kemi and Karstula in Northern and Central Finland the goal for using GPR was to inspect the condition and thickness of the wearing course and evaluate the need for additional wearing course material. The total length of the roads under survey was approximately 200 km and both a 1.5 GHz ground-coupled antenna and a 1.0 GHz horn antenna were tested in this study. The research results show that GPR can be used to measure the thickness of the wearing course, the average measuring error against reference drilling measurements being 25 mm, which is considerably larger than the error of radar measurements in paved roads. To a great extent this is due to the fact that the thickness of the wearing course varies greatly even in the road's cross-section and thus a single reference thickness does not represent the actual thickness of the area measured with the GPR. The wearing course can often get mixed up with lower layers, which makes it difficult to determine the exact layer interfaces. For this reason reference information must always be used along with the GPR measurement results. Of the two GPR antennae tested, the horn antenna proved to be the more effective in measurements. The dielectric value of the wearing course, measured using the horn

  12. Wear monitoring of protective nitride coatings using image processing

    DEFF Research Database (Denmark)

    Rasmussen, Inge Lise; Guibert, M.; Belin, M.

    2010-01-01

    A double-layer model system, consisting of a thin layer of tribological titanium aluminum nitride (TiAlN) on 17 top of titanium nitride (TiN), was deposited on polished 100Cr6 steel substrates. The TiAlN top-coatings 18 were exposed to abrasive wear by a reciprocating wear process in a linear tribo...... processing by color detection is a potential technique for early 25 warning or determination of residual thickness of tribological tool coatings prior to complete wear....

  13. Wear resistance of nodular cast iron with carbides

    Directory of Open Access Journals (Sweden)

    G. Gumienny

    2011-07-01

    Full Text Available In this paper results of abrasive and adhesive wear resistance of selected grades of nodular cast iron with carbides are presented. It was demonstrated, that the maximum wear resistance has got nodular cast iron with the microstructure of upper bainite, lower bainite and carbides. This cast iron with hardened steel and sulfonitrided steel is the most advantageous friction pair during adhesive wear testing. It was found, that the least advantageous friction pair is pearlitic nodular cast iron with carbides and normalized steel.

  14. Progress and development in thermodynamic theory of friction and wear

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Tribology theory lags well behind engineering needs because of those complex and multi-dimensional characteristics associated with friction and wear. The mechanism of friction is reviewed and discussed from a static thermodynamics perspective; research methods on the process of friction and wear and thermodynamic studies within the field of tribology are also reviewed. We propose that entropy can be a critical parameter in describing the evolution of friction and wear, and the entropy balance equation could be considered as a fundamental cornerstone for a systematic tribology theory. Applications of irreversible thermodynamic theory of tribology to various fields are reviewed.

  15. Progress and development in thermodynamic theory of friction and wear

    Institute of Scientific and Technical Information of China (English)

    DAI ZhenDong; XUE QunJi

    2009-01-01

    Tribology theory lags well behind engineering needs because of those complex and multi-dimensional characteristics associated with friction and wear. The mechanism of friction is reviewed end discussed from a static thermodynamics perspective; research methods on the process of friction and wear and thermodynamic studies within the field of tribology are also reviewed. We propose that entropy can be a critical parameter in describing the evolution of friction and wear, and the entropy balance equation could be considered as a fundamental cornerstone for a systematic tribology theory. Applications of irreversible thermodynamic theory of tribology to various fields are reviewed.

  16. A modeling of pump impeller shroud and wear-ring seal as a whole, and its application to the pump rotordynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Tae Woong [Kyungwon Univ., Sungnam (Korea, Republic of); Lee, An Sung [Korea Institute of Machinery and Materials, Taejon (Korea, Republic of)

    1998-06-01

    A modeling methodology of pump impeller shroud and wear-ring seal as a whole has been developed to give its rotordynamic coefficients. In this work the governing equations are derived for the continuous flow path of the impeller shroud and wear-ring seal. Pressure loss at the discontinuity of the connecting point between the impeller shroud and the wear-ring seal is defined by utilizing a pressure loss coefficient obtained from experimental measurements. The governing equations are solved directly by using the known conditions at the inlet of the impeller shroud and outlet of the wear-ring seal. A detailed rotordynamic analysis has been carried out on a 750 m-head fourteen-stage centrifugal pump system with the effects of the hydrodynamic forces of such as impeller shroud and wear-ring seals, balance piston, and interstage seals. Results have shown that the first critical speed obtained with all the seal effects is much higher than that obtained without those effects, and moreover that the system under consideration is unstable. Large cross coupled stiffness(k) of the impeller shroud and wear-ring seal has been suspected as the source of the problem. Design modifications of the impeller shroud and wear-ring seal geometry have been performed to decrease k and increase the direct damping(C). Finally, the design modifications have yielded a stable and well damped system.

  17. Standard test method for ranking resistance of plastics to sliding wear using block-on-ring wear test—cumulative wear method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of plastics to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank plastics according to their sliding wear characteristics against metals or other solids. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. In addition, the test can be run with different gaseous atmospheres and elevated temperatures, as desired, to simulate service conditions. 1.3 Wear test results are reported as the volume loss in cubic millimetres for the block and ring. Materials of higher wear resistance will have lower volume loss. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with it...

  18. Contact lens wear and microbial keratitis.

    Science.gov (United States)

    Ahuja, Markanday

    2002-11-01

    Common types of contact lens are hard, rigid gas-permeable or soft lenses. Most lenses are worn on a daily basis. Cosmetic lenses are worn for non-medical indications. Microbial keratitis, a rare but most significant complication is discussed in this article. Pseudomonas aeruginosa and staphylococci are the most common organisms cause infective keratitis. Fungi and acanthamoeba are also responsible. The causes of increased susceptibility to infection are poor lens hygiene, adhesion of bacteria to lens surface and hypoxia. Preventing measures to be taken while wearing contact lens are discussed in a nutshell. Ocular pain, conjunctival infection, photophobia, epiphora and reduced vision are some of the symptoms of corneal infection. Diagnostic laboratory investigations are to be carried out immediately when a microbial corneal ulcer is suspected. Acanthamoeba can be cultured from corneal scrapes. Immunologically based fluorescein labelling techniques appear to be more sensitive than simple staining. The treatment consists of medical and surgical intervention. Corneal thinning, descemetocele formation and perforation are possible complications.

  19. Wear Calculation for Sliding Friction Pairs

    Science.gov (United States)

    Springis, G.; Rudzitis, J.; Avisane, A.; Leitans, A.

    2014-04-01

    One of the principal objectives of modern production process is the improvement of quality level; this means also guaranteeing the required service life of different products and increase in their wear resistance. To perform this task, prediction of service life of fitted components is of crucial value, since with the development of production technologies and measuring devices it is possible to determine with ever increasing precision the data to be used also in analytical calculations. Having studied the prediction theories of wear process that have been developed in the course of time and can be classified into definite groups one can state that each of them has shortcomings that might strongly impair the results thus making unnecessary theoretical calculations. The proposed model for wear calculation is based on the application of theories from several branches of science to the description of 3D surface micro-topography, assessing the material's physical and mechanical characteristics, substantiating the regularities in creation of the material particles separated during the wear process and taking into consideration definite service conditions of fittings. ums Mūsdienu ražošanas procesa viens no pamatmērķiem ir produkcijas kvalitātes līmeņa paaugstināšana, tas nozīmē arī dažādu izstrādājumu nepieciešamā kalpošanas laika nodrošināšanu un nodilumizturības palielināšanu. Svarīga loma šī uzdevuma sasniegšanā ir salāgojamo detaļu kalpošanas laika prognozēšanai, kas ir ļoti aktuāls jautājums, jo attīstoties dažādām ražošanas, kā arī mēriekārtu tehnoloģijām, kļūst iespējams arvien precīzāk noteikt nepieciešamos datus, kuri vēlāk tiek izmantoti arī analītiskajos aprēķinos. Apskatot laika gaitā izstrādātās dilšanas procesa prognozēšanas teorijas, kuras var klasificēt, apkopojot tās noteiktās grupās, ņemot par pamatu līdzīgas teorētiskās pieejas, jāsaka, ka katrai no tām piemīt da

  20. Canine tooth wear in captive little brown bats

    Science.gov (United States)

    Clark, D.R.

    1980-01-01

    Upper canine teeth of little brown bats Myotis lucifugus lucifugus held in stainless steel wire mesh cages underwent severe wear which exceeded that observed previously in caged big brown bats, Eptesicus fuscus fuscus. This suggests a relationship between amount of wear and size of the caged bats with damage increasing as size decreases. Rapid wear of canine teeth by little brown bats resembled that observed in big brown bats in that it was limited to the first 2 weeks of captivity. This result indicates a universal interval for acclimation to cage conditions among vespertilionid bats. Dietary toxicants DDE and PCB did not affect the extent of wear. If bats are to be released to the wild, confinement in wire mesh cages should be avoided.

  1. Wear properties of nanosilica filled epoxy polymers and FRP composites

    Directory of Open Access Journals (Sweden)

    A. Jumahat

    2015-09-01

    Full Text Available This paper is aimed to determine the wear properties of nanosilica filled epoxy polymers and FRP composites. Woven fiberglass has been deployed as the reinforcement material. The fibers were mixed with three different percentages of nanosilica-modified epoxy resin, i.e: 5wt%; 13wt%; 25wt%, in order to fabricate the desired samples of FRP composites. The effect of nanosilica on wear properties was evaluated using dry sliding wear and slurry tests. The results show that increasing the amount of nanosilica content has reduced the amount of accumulated mass loss. It was found that the FRP laminates with 25wt% of nanosilica have the highest wear resistance. The nanosilica filled fiber reinforced polymer composites have a high potential in tribological application such as ball bearing housing and snow sleds.

  2. Wear resistant steels and casting alloys containing niobium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Theisen, W.; Siebert, S.; Huth, S. [Lehrstuhl Werkstofftechnik, Ruhr-Univ. Bochum (Germany)

    2007-12-15

    Niobium, like titanium and vanadium, forms superhard MC carbides that remain relatively pure in technical alloys on account of their low solubility for other metallic alloying elements. However, because they have a greater hardness than the precipitated chromium carbides commonly used in wear-resistant alloys, they are suitable as alternative hard phases. This contribution deals with new wear-resistant steels and casting alloys containing niobium carbide. These include a secondary hardening hardfacing alloy, a composite casting alloy for wear applications at elevated temperatures, a white cast iron as well as two variants of a corrosion-resistant cold-work tool steel produced by melt metallurgy and by powder metallurgy. A heat-resistant casting alloy is also discussed. Based on equilibrium calculations the microstructures developing during production of the alloys are analysed, and the results are discussed with respect to important properties such as abrasive wear and corrosion resistance. (orig.)

  3. Mitigation of wear damage by laser surface alloying technique

    CSIR Research Space (South Africa)

    Adebiyi, ID

    2016-04-01

    Full Text Available replacement costs, and all downtime costs related to such replacement. Consequently, companies will increasingly need to look to wear reduction as a direct, immediate avenue for maintaining output quotas and for cutting production costs. Laser coating...

  4. Abrasive wear behaviour of as cast and austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Baydogan, M.; Koekden, M.U.; Cimenoglu, H. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Science Engineering Istanbul (Turkey)

    2000-07-01

    In this study, abrasive wear behaviour of as cast and austempered GGG 50 and GGG 80 quality ductile irons was investigated. In the as cast condition, GGG 50 and GGG 80 quality ductile irons were having ferritic and pearlitic matrix structures, respectively. Austempering at 250 C after austenitisation at 900 C for 100 minutes produced bainitic matrix structure in both of the investigated ductile irons. Abrasive wear tests performed by rubbing the as cast and austempered specimens on Al{sub 2}O{sub 3} abrasive bands, revealed that austempering treatment improves abrasion resistance about 10-70% depending on the abrasive particle size and composition of the base iron. In the as cast condition, pearlitic GGG 80 grade ductile iron, has higher wear resistance than ferritic GGG 50 grade ductile iron. In the austempered condition GGG 50 and GGG 80 grade ductile irons which have bainitic matrix structure, exhibit almost similar wear resistance. (orig.)

  5. Influence Factors of Fractal Characterization of Reciprocating Sliding Wear Surfaces

    Institute of Scientific and Technical Information of China (English)

    周新聪; 冯伟; 严新平; 萧汉梁

    2004-01-01

    The principal purpose of this paper is to investigate influence factors of fractal characterization of reciprocating sliding wear surfaces.The wear testing was completed to simulate the real running condition of the diesel engine 8NVD48A-2U.The test results of wear surface morphology dimension characterization show that wear surface profiles have statistical self-affine fractal characteristics.In general, there are no effects of the profilometer sampling spacing and sampling length and evaluation length on the fractal dimensions of the surfaces.However, if the evaluation length is too short, the structure function logarithm of the surface profile is scattered.The sampling length acting as a filter is an important part of the fractal dimension measurement.If the sampling length is too short, the evaluation of the fractal dimension will have a larger standard deviation.The continuous wavelet transform can be used to improve surface profile dimension characterization.

  6. A Wear Geometry Model of Plain Woven Fabric Composites

    Directory of Open Access Journals (Sweden)

    Gu Dapeng

    2014-09-01

    Full Text Available The paper g describes a model meant for analysis of the wear geometry of plain woven fabric composites. The referred model consists of a mathematical description of plain woven fabric based on Peirce’s model coupled with a stratified method for the solution of the wear geometry. The evolutions of the wear area ratio of weft yarn, warp yarn and matrix resin on the worn surface are simulated by MatLab software in combination of warp and weft yarn diameters, warp and weft yarn-to-yarn distances, fabric structure phases (SPs. By comparing theoretical and experimental results from the PTFE/Kevlar fabric wear experiment, it can be concluded that the model can present a trend of the component area ratio variations along with the thickness of fabric, but has a inherently large error in quantitative analysis as an idealized model.

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

    Institute of Scientific and Technical Information of China (English)

    WAN Daping; HU Dejin; WU Qi; ZHANG Yonghong

    2006-01-01

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

  8. An Anthropological Perspective: Another Dimension to Modern Dental Wear Concepts

    Directory of Open Access Journals (Sweden)

    John A. Kaidonis

    2012-01-01

    Full Text Available For many years, research on tooth wear by dental academics has been diametrically opposite to that of anthropological research, with each discipline having a different understanding as to the nature of the wear processes. Dental focus revolved around preventive and restorative considerations while the anthropological focus was a biological understanding related to human evolution, diet, environment, form, and function and included all the craniofacial structures. Introducing the anthropological perspective into modern dentistry gives an insight into the “bigger picture” of the nature and extent of tooth wear. By combining anthropological evidence with clinical knowledge and experience, it is most likely to provide the best-informed and biologically based approach to the management of tooth wear in modern societies.

  9. Clinical studies of dental erosion and erosive wear

    National Research Council Canada - National Science Library

    Huysmans, M.C.D.N.J.M; Chew, H.P; Ellwood, R.P

    2011-01-01

    We define erosion as a partial demineralisation of enamel or dentine by intrinsic or extrinsic acids and erosive tooth wear as the accelerated loss of dental hard tissue through the combined effect...

  10. Friction and wear properties of N+ ion implanted nylon 1010

    Institute of Scientific and Technical Information of China (English)

    XIONG Dang-sheng

    2004-01-01

    The PA1010 was implanted with 450 keV N+ ions to three doses of 5× 1014 cm-2 , 2.5× 1015 cm-2 and 1.25 × 1016 cm-2. The friction and wear behaviors of the ion implanted PA1010 disks rubbing with two ceramic (ZrO2 and Si3N4) balls were studied using a pin-on-disk tribometer under dry friction. The results shows that the wear resistance of PA1010 is increased with the increasing implantation doses. The adhesion, plastic deformation and plow groove are wearing mechanisms for un-implanted PA1010, while abrasive wear for implanted PA1010.

  11. Wear and Friction Behavior of Metal Impregnated Microporous Carbon Composites

    Science.gov (United States)

    Goller, Gultekin; Koty, D. P.; Tewari, S. N.; Singh, M.; Tekin, A.

    1996-01-01

    Metal-matrix composites have been prepared by pressure-infiltration casting of copper-base alloy melts into microporous carbon preforms. The carbon preforms contained varying proportions of amorphous carbon and graphite. Load dependence of the wear and friction behavior of the composite pins has been examined under ambient conditions against cast-iron plates, using a pin-on-plate reciprocating wear tester. The wear resistance of the composite is significantly improved, as compared with the base alloy. Contrary to the normally expected behavior, the addition of graphite to the amorphous carbon does not reduce the friction coefficient, especially at high loads. The wear and friction behavior of the composites is very sensitive to the size and distribution of the microstructural constituents.

  12. Friction and wear methodologies for design and control

    CERN Document Server

    Straffelini, Giovanni

    2015-01-01

    This book introduces the basic concepts of contact mechanics, friction, lubrication, and wear mechanisms, providing simplified analytical relationships that are useful for quantitative assessments. Subsequently, an overview on the main wear processes is provided, and guidelines on the most suitable design solutions for each specific application are outlined. The final part of the text is devoted to a description of the main materials and surface treatments specifically developed for tribological applications and to the presentation of tribological systems of particular engineering relevance. The text is up to date with the latest developments in the field of tribology and provides a theoretical framework to explain friction and wear problems, together with practical tools for their resolution. The text is intended for students on Engineering courses (both bachelor and master degrees) who must develop a sound understanding of friction, wear, lubrication, and surface engineering, and for technicians or professi...

  13. Evaluating the accuracy of wear formulae for acetabular cup liners.

    Science.gov (United States)

    Wu, James Shih-Shyn; Hsu, Shu-Ling; Chen, Jian-Horng

    2010-02-01

    This study proposes two methods for exploring the wear volume of a worn liner. The first method is a numerical method, in which SolidWorks software is used to create models of the worn out regions of liners at various wear directions and depths. The second method is an experimental one, in which a machining center is used to mill polyoxymethylene to manufacture worn and unworn liner models, then the volumes of the models are measured. The results show that the SolidWorks software is a good tool for presenting the wear pattern and volume of a worn liner. The formula provided by Ilchmann is the most suitable for computing liner volume loss, but is not accurate enough. This study suggests that a more accurate wear formula is required. This is crucial for accurate evaluation of the performance of hip components implanted in patients, as well as for designing new hip components.

  14. WEAR-RESISTANCE OF CHROMIC CAST IRONS OF EUTECTIC COMPOSITION

    Directory of Open Access Journals (Sweden)

    K. E. Baranovskij

    2009-01-01

    Full Text Available Casting of wear-resistant chrome cast irons in combined molds and iron chills is studied. Application of these ways of casting results in blending of carbides and increasing of hardness of castings.

  15. Hardfacing materials used in valves for seating and wear surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Knecht, W.G.

    1996-12-01

    Most valves and essentially all critical service valves utilize hardfacing materials for seating and wear surfaces to minimize wear and galling. The type of hardfacing materials used, the methods of deposition, and the quality of the final product all contribute to the wear characteristics, required operating force, and life of the final product. Over the last forty years the most prevalent hardfacing materials furnished to the commercial nuclear industry consisted of cobalt base and nickel base materials. In the last several years there has been extensive development and evaluation work performed on iron base hardfacing materials. This presentation will address the wear characteristics of the various materials and the importance of consistent quality of deposited materials necessary to achieve optimum product performance and longevity.

  16. Evaluation Of Saltstone Mixer Paddle Configuration For Improved Wear Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M. M.; Fowley, M. D.; Pickenheim, B. R.

    2012-09-27

    A soft metal with low wear resistance (6000 series aluminum), was used to minimize run time while maximizing wear rate. Two paddle configurations were tested, with the first four paddles after the augers replaced by the wear paddles. The first configuration was all flat paddles, with the first paddle not aligned with the augers and is consistent with present SPF mixer. The second configuration had helical paddles for the first three stages after the augers and a flat paddle at the fourth stage. The first helical paddle was aligned with the auger flight for the second configuration. The all flat paddle configuration wear rate was approximately double the wear rate of the helical paddles for the first two sets of paddles after the augers. For both configurations, there was little or no wear on the third and fourth paddle sets based on mass change, indicating that the fully wetted premix materials are much less abrasive than the un-wetted or partially wetted premix. Additionally, inspection of the wear surface of the paddles at higher magnification showed the flat paddles were worn much more than the helical and is consistent with the wear rates. Aligning the auger discharge flight with the first set of helical paddles was effective in reducing the wear rate as compared to the flat paddle configuration. Changing the paddle configuration from flat to helical resulted in a slight increase in rheological properties. Although, both tests produced grout-like material that is within the processing rage of the SPF, it should be noted that cement is not included in the premix and water was used rather than salt solution, which does affect the rheology of the fresh grout. The higher rheological properties from the helical wear test are most likely due to the reduced number of shearing paddles in the mixer. In addition, there is variation in the rheological data for each wear test. This is most likely due to the way that the dry feeds enter the mixer from the dry feeder. The

  17. Policies for Probe-Wear Leveling in MEMS-Based Storage Devices

    NARCIS (Netherlands)

    Khatib, M.G.; Hartel, P.H.

    2009-01-01

    Probes (or read/write heads) in MEMS-based storage devices are susceptible to wear. We study probe wear, and analyze the causes of probe uneven wear. We show that under real-world traces some probes can wear one order of magnitude faster than other probes leading to premature expiry of some probes.

  18. Friction and wear of zirconia and alumina ceramics doped with CuO

    NARCIS (Netherlands)

    Pasaribu, Henry Rihard

    2005-01-01

    In this thesis, a wear model is developed that relates the properties of the materials and the operating conditions to the type of wear (mild or severe wear) experienced by dry sliding ceramic systems. The wear model is verified experimentally, and hence, with this model, one can determine wheather

  19. TRIBOLOGICAL PROPERTIES AND WEAR MECHANISM OF HARD COATINGS

    OpenAIRE

    Ugues, Daniele; Maizza, Giovanni

    2013-01-01

    In the modern technology, tribologically suitable components and devices are important to increase the energy efficiency. It is possible when one can reduce the friction coefficient and wear of sliding components. The economic effectiveness can be achieved by better tribological system and therefore research in tribology is aimed at minimizing the energy losses resulting from friction and wear. In this view, hard coatings deposited by physical vapor deposition (PVD) are adequate solutions for...

  20. Corrosion and wear resistant metallic layers produced by electrochemical methods

    DEFF Research Database (Denmark)

    Christoffersen, Lasse; Maahn, Ernst Emanuel

    1999-01-01

    Corrosion and wear-corrosion properties of novel nickel alloy coatings with promising production characteristics have been compared with conventional bulk materials and hard platings. Corrosion properties in neutral and acidic environments have been investigated with electrochemical methods....... Determination of polarisation resistance during 100 hours followed by stepwise anodic polarisation seems to be a promising technique to obtain steady state data on slowly corroding coatings with transient kinetics. A slurry test enables determination of simultaneous corrosion and abrasive wear. Comparison...

  1. Wear Assessment of Conical Pick used in Coal Cutting Operation

    Science.gov (United States)

    Dewangan, Saurabh; Chattopadhyaya, Somnath; Hloch, Sergej

    2015-09-01

    Conical pick is a widely used tool for cutting coal in mines. It has a cemented carbide tip inserted in a steel body. Cemented carbide has been in use for many years for coal/rock cutting because it has the optimum combination of hardness, toughness and resistance against abrasive wear. As coal/rock is a heterogeneous substance, the cutting tool has to undergo various obstructions at the time of excavation that cause the tool to wear out. The cracks and fractures developing in the cemented carbide limit the life of the tool. For a long time, different wear mechanisms have been studied to develop improved grades of cemented carbide with high wear resistance properties. The research is still continuing. Moreover, due to the highly unpredictable nature of coal/rock, it is not easy to understand the wear mechanisms. In the present work, an attempt has been made to understand the wear mechanisms in four conical picks, which were used in a continuous miner machine for underground mining of coal. The wearing pattern of the conical pick indicates damage in its cemented carbide tip as well as the steel body. The worn out parts of the tools have been critically examined using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) point analysis. Mainly four types of wear mechanisms, namely, coal/rock intermixing, plastic deformation, rock channel formation and crushing and cracking, have been detected. The presence of coal/rock material and their respective concentrations in the selected area of worn out surface were observed using the spectra generated by EDX analysis.

  2. Dry sliding wear of heat treated hybrid metal matrix composites

    Science.gov (United States)

    Naveed, Mohammed; Khan, A. R. Anwar

    2016-09-01

    In recent years, there has been an ever-increasing demand for enhancing mechanical properties of Aluminum Matrix Composites (AMCs), which are finding wide applications in the field of aerospace, automobile, defence etc,. Among all available aluminium alloys, Al6061 is extensively used owing to its excellent wear resistance and ease of processing. Newer techniques of improving the hardness and wear resistance of Al6061 by dispersing an appropriate mixture of hard ceramic powder and whiskers in the aluminium alloy are gaining popularity. The conventional aluminium based composites possess only one type of reinforcements. Addition of hard reinforcements such as silicon carbide, alumina, titanium carbide, improves hardness, strength and wear resistance of the composites. However, these composites possessing hard reinforcement do posses several problems during their machining operation. AMCs reinforced with particles of Gr have been reported to be possessing better wear characteristics owing to the reduced wear because of formation of a thin layer of Gr particles, which prevents metal to metal contact of the sliding surfaces. Further, heat treatment has a profound influence on mechanical properties of heat treatable aluminium alloys and its composites. For a solutionising temperature of 5500C, solutionising duration of 1hr, ageing temperature of 1750C, quenching media and ageing duration significantly alters mechanical properties of both aluminium alloy and its composites. In the light of the above, the present paper aims at developing aluminium based hybrid metal matrix composites containing both silicon carbide and graphite and characterize their mechanical properties by subjecting it to heat treatment. Results indicate that increase of graphite content increases wear resistance of hybrid composites reinforced with constant SiC reinforcement. Further heat treatment has a profound influence on the wear resistance of the matrix alloy as well as its hybrid composites

  3. Size Dependence of Nanoscale Wear of Silicon Carbide.

    Science.gov (United States)

    Tangpatjaroen, Chaiyapat; Grierson, David; Shannon, Steve; Jakes, Joseph E; Szlufarska, Izabela

    2017-01-18

    Nanoscale, single-asperity wear of single-crystal silicon carbide (sc-SiC) and nanocrystalline silicon carbide (nc-SiC) is investigated using single-crystal diamond nanoindenter tips and nanocrystalline diamond atomic force microscopy (AFM) tips under dry conditions, and the wear behavior is compared to that of single-crystal silicon with both thin and thick native oxide layers. We discovered a transition in the relative wear resistance of the SiC samples compared to that of Si as a function of contact size. With larger nanoindenter tips (tip radius ≈ 370 nm), the wear resistances of both sc-SiC and nc-SiC are higher than that of Si. This result is expected from the Archard's equation because SiC is harder than Si. However, with the smaller AFM tips (tip radius ≈ 20 nm), the wear resistances of sc-SiC and nc-SiC are lower than that of Si, despite the fact that the contact pressures are comparable to those applied with the nanoindenter tips, and the plastic zones are well-developed in both sets of wear experiments. We attribute the decrease in the relative wear resistance of SiC compared to that of Si to a transition from a wear regime dominated by the materials' resistance to plastic deformation (i.e., hardness) to a regime dominated by the materials' resistance to interfacial shear. This conclusion is supported by our AFM studies of wearless friction, which reveal that the interfacial shear strength of SiC is higher than that of Si. The contributions of surface roughness and surface chemistry to differences in interfacial shear strength are also discussed.

  4. Friction and Wear of Sintered Alumina at High Temperature

    OpenAIRE

    Senda, Tetsuya; TAKAHASHl, Chiori; UEMATSU, Susumu; Amada, Shigeyasu

    1991-01-01

    The frictional behavior of alumina ceramics was investigated at various temperatures up to 1200℃. The coefficient of friction decreased with increasing temperature and this temperature dependency became more pronounced as higher contact pressures were applied. Wear loss at room temperature could be interpreted as being caused by one of either two different behavior modes. These have a rate difference of a factor of ten. At temperatures higher than 800℃, the wear loss was far less than that at...

  5. SPECFACE - A Dataset of Human Faces Wearing Spectacles

    OpenAIRE

    2015-01-01

    This paper presents a database of human faces for persons wearing spectacles. The database consists of images of faces having significant variations with respect to illumination, head pose, skin color, facial expressions and sizes, and nature of spectacles. The database contains data of 60 subjects. This database is expected to be a precious resource for the development and evaluation of algorithms for face detection, eye detection, head tracking, eye gaze tracking, etc., for subjects wearing...

  6. The wear of cross-linked polyethylene against itself.

    Science.gov (United States)

    Joyce, T J; Ash, H E; Unsworth, A

    1996-01-01

    Cross-linked polyethylene (XLPE) may have an application as a material for an all-plastic surface replacement finger joint. It is inexpensive, biocompatible and can be injection-moulded into the complex shapes that are found on the ends of the finger bones. Further, the cross-linking of polyethylene has significantly improved its mechanical properties. Therefore, the opportunity exists for an all-XLPE joint, and so the wear characteristics of XLPE sliding against itself have been investigated. Wear tests were carried out on both reciprocating pin-on-plate machines and a finger function simulator. The reciprocating pin-on-plate machines had pins loaded at 10 N and 40 N. All pin-on-plate tests show wear factors from the plates very much greater than those of the pins. After 349 km of sliding, a mean wear factor of 0.46 x 10(-6) mm3/N m was found for the plates compared with 0.021 x 10(-6) mm3/N m for the pins. A fatigue mechanism may be causing this phenomenon of greater plate wear. Tests using the finger function simulator give an average wear rate of 0.22 x 10(-6) mm3/N m after 368 km. This sliding distance is equivalent to 12.5 years of use in vivo. The wear factors found were comparable with those of ultra-high molecular weight polyethylene (UHMWPE) against a metallic counterface and, therefore, as the loads across the finger joint are much less than those across the knee or the hip, it is probable that an all-XLPE finger joint will be viable from a wear point of view.

  7. Indirect multisignal monitoring and diagnosis of drill wear

    OpenAIRE

    Jantunen, Erkki

    2006-01-01

    A machine tool utilisation rate can be improved by an advanced condition monitoring system using modern sensor and signal processing techniques. A drilling test and analysis program for indirect tool wear measurement forms the basis of this thesis. For monitoring the drill wear a number of monitoring methods such as vibration, acoustic emission, sound, spindle power and axial force were tested. The signals were analysed in the time domain using statistical methods such as root mean square (rm...

  8. Detecting Safety Zone Drill Process Parameters for Uncoated HSS Twist Drill in Machining GFRP Composites by Integrating Wear Rate and Wear Transition Mapping

    Directory of Open Access Journals (Sweden)

    Sathish Rao Udupi

    2016-01-01

    Full Text Available The previous research investigations informed that the tool wear of any machining operation could be minimized by controlling the machining factors such as speed, feed, geometry, and type of cutting tool. Hence the present research paper aims at controlling the process parameters to minimize the drill tool wear, during the machining of Glass Fiber Reinforced Polymer (GFRP composites. Experiments were carried out to find the tool wear rate and a wear mechanism map of uncoated High Speed Steel (HSS drill of 10 mm diameter was developed for the drilling of GFRP composite laminates. The surface micrograph images on the drill land surface displayed dominant wear mechanisms induced on HSS drill during machining of GFRP and they were found to be adhesive wear, adhesive and abrasive wear, abrasive wear, and diffusion and fatigue wear. A “safety wear zone” was identified on the wear mechanism map, where the minimum tool wear of the HSS drill occurs. From the safety zone boundaries, it was inferred that the drill spindle speed should be set between 1200 and 1590 rpm and feed rate must be set within a range of 0.10–0.16 mm/rev for GFRP work and HSS tool combination to enhance the service life of 10 mm HSS drills and to minimize the tool wear.

  9. Friction and wear of iron in sulfuric acid

    Science.gov (United States)

    Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

    1983-01-01

    Elemental iron sliding on aluminum oxide in aerated sulfuric acid concentrations ranging from very dilute (0.000007 N; i.e., 4 ppm) to very concentrated (96 percent acid) was studied. Load and reciprocating sliding speeds were kept constant. With the most dilute acid of 0.7 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent, the high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid, and decreased somewhat at 50 percent in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It is apparent that the normal passivating film was being worn away and a galvanic cell established which rapidly attached to the wear area.

  10. Plastic deformation wear in modified medium manganese steel

    Directory of Open Access Journals (Sweden)

    YUAN Hai-lun

    2007-08-01

    Full Text Available A medium manganese steel with high wear-resistance, strength and toughness has been produced with addition of a complex modifier (or refining agent containing Nb, N, RE and Si-Ca. The results showed that the wear resistance, strength and toughness of the modified medium manganese steel are respectively 1.92 times, 1.45 times and 3.63 times as high as that of the referenced unmodified medium manganese steel. The plastic deformation characteristic involved in the wear mechanism of the modified medium manganese steel was investigated by means of plastic-elasticity calculation and TEM electro-microscopy. The relationship between wear resistance and yield strength of the steel was established. Since the wear volume W is proportional to the square of the loading and to the numbers of the abrasives, and inversely proportional to the square of the yield strength of the materials, the wear resistance can be substantially improved by the enhancement of yield strength of the materials. The calculation results generally agreed with the experimental results.

  11. 3D cutting tool-wear monitoring in the process

    Energy Technology Data Exchange (ETDEWEB)

    Cerce, Luka; Pusavec, Franci; Kopac Janez [University of Ljubljana, Askerceva (Slovenia)

    2015-09-15

    The tool-wear of cutting tools has a very strong impact on the product quality as well as efficiency of the machining processes. Therefore, it in-the process characterization is crucial. This paper presents an innovative and reliable direct measuring procedure for measuring spatial cutting tool-wear with usage of laser profile sensor. The technique provides possibility for determination of 3D wear profiles, as advantage to currently used 2D techniques. The influence of the orientation of measurement head on the accuracy and the amount of captured reliable data was examined and the optimal setup of the measuring system was defined. Further, a special clamping system was designed to mount the measurement device on the machine tool turret. To test the measurement system, tool-life experiment was performed. Additionally, a new tool-life criterion was developed, including spatial characteristics of the tool-wear. The results showed that novel tool-wear and tool-life diagnostic represent objective and robust estimator of the machining process. Additionally, such automation of tool-wear diagnostics on machine tool provides higher productivity and quality of the machining process.

  12. Wear Performance of Cu-Alloyed Austempered Ductile Iron

    Science.gov (United States)

    Batra, Uma; Batra, Nimish; Sharma, J. D.

    2013-04-01

    An investigation was carried out to examine the influence of structural and mechanical properties on wear behavior of austempered ductile iron (ADI). Ductile iron (DI) samples were austenitized at 900 °C for 60 min and subsequently austempered for 60 min at three temperatures: 270, 330, and 380 °C. Microstructures of the as-cast DI and ADIs were characterized using optical and scanning microscopy, respectively. The structural parameters, volume fraction of austenite, carbon content of austenite, and ferrite particle size were determined using x-ray diffraction technique. Mechanical properties including Vicker's hardness, 0.2% proof strength, ultimate tensile strength, ductility, and strain hardening coefficient were determined. Wear tests were carried out under dry sliding conditions using pin-on-disk machine with a linear speed of 2.4 m/s. Normal load and sliding distance were 45 N and 1.7 × 104 m, respectively. ADI developed at higher austempering temperature has large amounts of austenite, which contribute toward improvement in the wear resistance through stress-induced martensitic transformation, and strain hardening of austenite. Wear rate was found to depend on 0.2% proof strength, ductility, austenite content, and its carbon content. Study of worn surfaces and nature of wear debris revealed that the fine ausferrite structure in ADIs undergoes oxidational wear, but the coarse ausferrite structure undergoes adhesion, delamination, and mild abrasion too.

  13. Plastic deformation wear in modified medium manganese steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A medium manganese steel with high wear-resistance, strength and toughness has been produced with addition of a complex modifier (or refining agent) containing Nb, N, RE and Si-Ca. The results showed that the wear resistance, strength and toughness of the modified medium manganese steel are respectively 1.92 times, 1.45times and 3.63 times as high as that of the referenced unmodified medium manganese steel. The plastic deformation characteristic involved in the wear mechanism of the modified medium manganese steel was investigated by means of plastic-elasticity calculation and TEM electro-microscopy. The relationship between wear resistance and yield strength of the steel was established. Since the wear volume W is proportional to the square of the loading and to the numbers of the abrasives, and inversely proportional to the square of the yield strength of the materials, the wear resistance can be substantially improved by the enhancement of yield strength of the materials. The calculation results generally agreed with the experimental results.

  14. Wear Fault Diagnosis of Machinery Based on Neural Networks and Gray Relationships

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the regular characteristic of wear particles related to fault type of machines based on condition monitoring of reciprocal machinery is discussed. The typi-cal wear particles spectrum is established according to the equipment structure, friction and wear rule and the characteristic of wear particles; The identification technology of wear particles is proposed based on neural networks and a gray relationship; an intelligent wear particles identification system is designed. The diagnosis example shows that this system can promote the accuracy and the speed of wear particles identification.

  15. Distribution Characteristics of Wear Particles from Material of Machine Elements in Lubricant condition

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yon Sang; Jun, Sung Jae; Kim, Young Hee; Park, Heung Sik [Donga Univ., Busan (Korea, Republic of)

    2007-07-01

    It necessarily follows that wear particles are generated through a friction and wear in a mechanical moving system. The wear particles are relative to the failure and the life of machine elements directly. To analyze the wear particle, its shape characteristics were calculated quantitative values such as diameter, roundness and fractal parameters by digital image processing. In this study, the histograms of shape parameters of wear particles were used for the purpose of analyzing the distribution of wear particles in various conditions. We consider that the histogram of shape parameter can be effectively represented to study a wear mechanism.

  16. Calculation of the Intensity of Adhesive-Fatigue Wear of Cutting Tools

    Science.gov (United States)

    Bibik, V.; Ivushkina, N.; Arhipova, D.

    2016-08-01

    On the base of kinetic equation of strength the authors suggest the method carbide tools wear intensity calculation allowing comparing wear resistance basing on tool material thermal diffusivity coefficient. The authors obtain equations of tool wear resistance dependences upon its thermal diffusivity which show close correlation between these parameters. The results of wear intensity calculations correspond well to the experimental results under the cutting rates corresponding to the region of adhesive-fatigue wear. The inserts with low thermal diffusivity coefficient are characterized by lower wear rate at the inial and normal stages of wear.

  17. Dry friction and wear properties of intermetallics MoSi2

    Institute of Scientific and Technical Information of China (English)

    张厚安; 刘心宇; 陈平; 唐果宁

    2001-01-01

    The dry friction and wear properties of intermetallics MoSi2 against 45 steel under different loads were investigated with M-2 type friction and wear tester. Scanning electric microscope (SEM) equipment with microprobe was employed to analyze the morphology of the friction surface. Results show that the dry friction and wear properties are deeply affected by load. The wear rate of MoSi2 at the load of 80 N is the maximum which is 36.1 μg/m. On the condition of the load of 150 N, MoSi2 material has the better friction and wear properties: friction coefficient is 0.28 and wear rate is 10.6μg/m. With the load increasing, the main friction mechanisms change from microslip and plastic deformation to adhesive effect, and the main wear mechanisms change from plough-groove wear and oxidation-fatigue wear to adhesive wear.

  18. Characterization of Wear Particles Generated from CoCrMo Alloy under Sliding Wear Conditions.

    Science.gov (United States)

    Pourzal, R; Catelas, I; Theissmann, R; Kaddick, C; Fischer, A

    2011-07-29

    Biological effects of wear products (particles and metal ions) generated by metal-on-metal (MoM) hip replacements made of CoCrMo alloy remain a major cause of concern. Periprosthetic osteolysis, potential hypersensitivity response and pseudotumour formation are possible reactions that can lead to early revisions. To accurately analyse the biological response to wear particles from MoM implants, the exact nature of these particles needs to be characterized. Most previous studies used energy-dispersive X-ray spectroscopy (EDS) analysis for characterization. The present study used energy filtered transmission electron microscopy (TEM) and electron diffraction pattern analysis to allow for a more precise determination of the chemical composition and to gain knowledge of the crystalline structure of the wear particles.Particles were retrieved from two different test rigs: a reciprocating sliding wear tribometer (CoCrMo cylinder vs. bar) and a hip simulator according to ISO 14242-1 (CoCrMo head vs. CoCrMo cup). All tests were conducted in bovine serum. Particles were retrieved from the test medium using a previously published enzymatic digestion protocol.Particles isolated from tribometer samples had a size of 100 - 500 nm. Diffraction pattern analysis clearly revealed the lattice structure of strain induced hcp ε-martensite. Hip simulator samples revealed numerous particles of 15 - 30 nm and 30 - 80 nm size. Most of the larger particles appeared to be only partially oxidized and exhibited cobalt locally. The smallest particles were Cr(2)O(3) with no trace of cobalt. It optically appeared that these Cr(2)O(3) particles were flaking off the surface of larger particles that depicted a very high intensity of oxygen, as well as chromium, and only background noise of cobalt. The particle size difference between the two test rigs is likely related to the conditions of the two tribosystems, in particular the difference in the sample geometry and in the type of sliding

  19. Isolation and Characterization of Wear Debris Generated in Patients Wearing Polyethylene Hylamer Inserts, Gamma Irradiated in Air

    OpenAIRE

    2005-01-01

    Abstract Hylamer polyethylene was used in the early 1990s to make hip-joint components. Clinical experience has shown that these components, if sterilized by gamma rays in the presence of oxygen, are easily affected by wear, which then leads to osteolysis. The authors analyzed polyethylene wear particles in seven patients who had received Hylamer polyethylene implants sterilized by gamma rays in air and had...

  20. Total hip wear assessment: a comparison between computational and in vitro wear assessment techniques using ISO 14242 loading and kinematics.

    Science.gov (United States)

    Matsoukas, George; Willing, Ryan; Kim, Il Yong

    2009-04-01

    In the present study a direct comparison was made between in vitro total hip wear testing and a computational analysis considering the effects of time and a nonlinear stress-strain relationship for ultrahigh molecular weight polyethylene (UHMWPE) at 37 degrees C. The computational simulation was made correct through calibration to experimental volumetric wear results, and the predicted damage layout on the acetabular liner surface was compared with results estimated from laser scanning of the actual worn specimens. The wear rates for the testing specimens were found to be 17.14+/-1.23 mg/10(6) cycles and 19.39+/-0.79 mg/10(6) cycles, and the cumulative volumetric wear values after 3x10(6) cycles were 63.70 mm(3) and 64.02 mm(3) for specimens 1 and 2, respectively. The value of the calibrated wear coefficient was found to be 5.32(10(-10)) mm(3)/N mm for both specimens. The major difference between the computational and experimental wear results was the existence of two damage vectors in the experimental case. The actual location of damage was virtually the same in both cases, and the maximum damage depth of the computational model agreed well with the experiment. The existence of multiple wear vectors may indicate the need for computational approaches to account for multidirectional sliding or strain hardening of UHMWPE. Despite the limitation in terms of describing the overall damage layout, the present computational model shows that simulation can mimic some of the behavior of in vitro wear.

  1. Isolation and Characterization of Wear Debris Generated in Patients Wearing Polyethylene Hylamer Inserts, Gamma Irradiated in Air

    OpenAIRE

    Visentin, M; Stea, S.; Squarzoni, S.; Reggiani, M.; Fagnano, C.; Antonietti, B.; Toni, A.

    2005-01-01

    International audience; Hylamer polyethylene was used in the early 1990s to make hip-joint components. Clinical experience has shown that these components, if sterilized by gamma rays in the presence of oxygen, are easily affected by wear, which then leads to osteolysis. The authors analyzed polyethylene wear particles in seven patients who had received Hylamer polyethylene implants sterilized by gamma rays in air and had suffered prosthetic loosening. The results were compared to those of si...

  2. Standard guide for measuring the wear volumes of piston ring segments run against flat coupons in reciprocating wear tests

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This guide covers and describes a profiling method for use accurately measuring the wear loss of compound-curved (crowned) piston ring specimens that run against flat counterfaces. It does not assume that the wear scars are ideally flat, as do some alternative measurement methods. Laboratory-scale wear tests have been used to evaluate the wear of materials, coatings, and surface treatments that are candidates for piston rings and cylinder liners in diesel engines or spark ignition engines. Various loads, temperatures, speeds, lubricants, and durations are used for such tests, but some of them use a curved piston ring segment as one sliding partner and a flat or curved specimen (simulating the cylinder liner) as its counterface. The goal of this guide is to provide more accurate wear measurements than alternative approaches involving weight loss or simply measuring the length and width of the wear marks. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its ...

  3. Effect of Alloying Elements on Thermal Wear of Cast Hot-Forging Die Steels

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-qi; CHEN Kang-min; CUI Xiang-hong; JIANG Qi-chuan; HONG Bian

    2006-01-01

    The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2% to 3%, respectively. With further increase of chromium and molybdenum contents, chromium slightly reduces the wear resistance and molybdenum severely deteriorates the wear resistance with high wear rate. Lower vanadium/carbon ratio (1.5-2.5) leads to a lower wear resistance with higher wear rate. With an increase in vanadium/carbon ratio, the wear resistance of the cast steel substantially increases. When vanadium/carbon ratio is 3, the wear rate reaches the lowest value. The predominant mechanism of thermal wear of cast hot-forging die steels are oxidation wear and fatigue delamination. The Fe2O3 and Fe3O4 or lumps of brittle wear debris are formed on the wear surface.

  4. Wear mechanism for spray deposited Al-Si/SiCp composites under dry sliding condition

    Institute of Scientific and Technical Information of China (English)

    滕杰; 李华培; 陈刚

    2015-01-01

    Al-Si/15%SiCp (volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy (OM). Dry sliding wear tests were carried out using a block-on-ring wear machine to investigate the effect of applied load range of 10−220 N on the wear and friction behavior of these composites sliding against SAE 52100 grade bearing steel. Scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX) were utilized to examine the morphologies of the worn surfaces in order to observe the wear characteristics and investigate the wear mechanism. The results show that the wear behavior of these composites is dependent on the silicon content in the matrix alloy and the applied load. Al-Si/15%SiCp composites with higher silicon content exhibit better wear resistance in the applied load range. Under lower loads, the major wear mechanisms are oxidation wear and abrasive wear for all tested composites. Under higher loads, severe adhesive wear becomes the main wear mechanisms for Al-7Si/15%SiCp and Al-13Si/15%SiCp composites, while Al-20Si/15%SiCp presents a compound wear mechanism, consisting of oxidation, abrasive wear and adhesion wear.

  5. THE EFFECT OF WEARING HEADSCARVES ON CERVICAL SPINE PROPRIOCEPTION

    Directory of Open Access Journals (Sweden)

    Samiah F. Alqabbani

    2016-04-01

    Full Text Available Background: Proprioception plays an important role in sensorimotor control of posture and movement. Impairments in cervical proprioception have been demonstrated in subjects with whiplash-associated disorder, patients with age-related degeneration, and patients with articular diseases or spondylosis. The joint position error test is widely used to measure head repositioning accuracy. Objective: The purpose of this pilot study was to compare cervical spine joint position error in females who routinely wear headscarves to females that do not wear headscarves. Methods: Twelve females with mean age 27.5±4.0 years were divided into two groups: females who routinely wear headscarves (n=6, and females who never wear headscarves (n=6. Joint position error was measured using a head-mounted laser while subjects were seated. The tasks involved relocating the head to neutral after flexion, extension, right rotation, and left rotation. A total of six trials were done for each direction. Results: The joint position error was higher in females wearing headscarves compared to females who do not wear them in the cumulative joint position error score (8.2±1.0 vs. 4.4±1.0, p=0.06 as well as during head rotation to the right (9.3±1.6 vs. 3.1±1.6, p=0.06. Conclusion: Wearing headscarves may increase the cervical joint position error and can negatively impact postural control. However, further studies are needed to confirm this finding.

  6. Fissure sealant materials: Wear resistance of flowable composite resins.

    Science.gov (United States)

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  7. Comparative Evaluation of Wear Rate of Different Riva Glass Ionomers

    Directory of Open Access Journals (Sweden)

    Vahid Yaghoubi

    2016-12-01

    Full Text Available Introduction: wear is one of the most important factors that cause loss of restorations. The aim of this study was to evaluate the wear rate in light-cured glass ionomers SDI. Materials and Methods: 20 samples consisted of light-cured Ionomer Glass Riva and Riva HV and Fuji II and composit Z250 to 2mm and length and width 10mm in Copper generator were prepared (n = 5 and were put in a wear device. Samples in wear cycles, in the course of 5000, 10000, 20000, 40000, 80000, 120000 respectively cycles via cobalt chrome cylindrical abrasive was under wear. Digital scale with 0.1 mg precision was used for gravimetric. Data using One Way Anova and Post hoc Tukey test and Spss software was analyzed. Results: The weight loss was as follows: Glass Ionomer light cure Riva ˂Glass Ionomer light cure Riva HV ˂Glass Ionomer light cure Fuji II ˂composite Z250. The other three groups were statistically significant weight loss between the composite Z250 and but the difference in weight loss between the groups and Glass Ionomer light cure Riva, Glass Ionomer light cure Riva HV, Glass Ionomer light cure Fuji II was found after 120,000 cycles. Conclusion: The results of this study showed the wear of glass ionomers Capsule Riva is similar Fuji II LC but the wear of glass inomers is much more than composite Z250 which seems ready to take in areas not exposed to occlusal stress.

  8. Fissure sealant materials: Wear resistance of flowable composite resins

    Directory of Open Access Journals (Sweden)

    Sohrab Asefi

    2016-08-01

    Full Text Available Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow, Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists. A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  9. Fissure sealant materials: Wear resistance of flowable composite resins

    Science.gov (United States)

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics. PMID:27651887

  10. Surface roughness and wear of resin cements after toothbrush abrasion

    Directory of Open Access Journals (Sweden)

    Sérgio Kiyoshi ISHIKIRIAMA

    2015-01-01

    Full Text Available Increased surface roughness and wear of resin cements may cause failure of indirect restorations. The aim of this study was to evaluate quantitatively the surface roughness change and the vertical wear of four resin cements subjected to mechanical toothbrushing abrasion. Ten rectangular specimens (15 × 5 × 4 mm were fabricated according to manufacturer instructions for each group (n = 10: Nexus 3, Kerr (NX3; RelyX ARC, 3M ESPE (ARC; RelyX U100, 3M ESPE (U100; and Variolink II, Ivoclar/Vivadent (VL2. Initial roughness (Ra, µm was obtained through 5 readings with a roughness meter. Specimens were then subjected to toothbrushing abrasion (100,000 cycles, and further evaluation was conducted for final roughness. Vertical wear (µm was quantified by 3 readings of the real profile between control and brushed surfaces. Data were subjected to analysis of variance, followed by Tukey’s test (p < 0.05. The Pearson correlation test was performed between the surface roughness change and wear (p < 0.05. The mean values of initial/final roughness (Ra, µm/wear (µm were as follows: NX3 (0.078/0.127/23.175; ARC (0.086/0.246/20.263; U100 (0.296/0.589/16.952; and VL2 (0.313/0.512/22.876. Toothbrushing abrasion increased surface roughness and wear of all resin cements tested, although no correlation was found between those variables. Vertical wear was similar among groups; however, it was considered high and may lead to gap formation in indirect restorations.

  11. Wear mechanism and wear prevention in coal-fueled diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-20

    The overall objective of this program is to develop the diesel engine and lubricant system design approach that has the highest probability for commercial acceptance. Several specific objectives can also be identified. These objectives include: Definition of the dominant wear mechanisms prevailing in coal-fueled diesel engines; Definition of the specific effect of each coal-related lube oil contaminant; Determination of the potential of traditional engine lubrication design approaches to either solve or mitigate the effects of the coal related lube oil contaminants; Evaluation of several different engine design approaches aimed specifically at preventing lube oil contamination or preventing damage due to lube oil contamination; and Presentation of the engine/lubricant system design determined to have the most potential.

  12. Extensive Bone Reaction From Catastrophic Oxidized Zirconium Wear.

    Science.gov (United States)

    Cassar-Gheiti, Adrian J; Collins, Dennis; McCarthy, Tom

    2016-01-01

    The use of alternative bearing surfaces for total hip arthroplasty has become popular to minimize wear and increase longevity, especially in young patients. Oxidized zirconium (Oxinium; Smith & Nephew, Memphis, Tennessee) femoral heads were introduced in the past decade for use in total hip arthroplasty. The advantages of oxidized zirconium include less risk of fracture compared with traditional ceramic heads. This case report describes a patient with a history of bilateral avascular necrosis of the femoral head after chemotherapy for acute lymphoblastic leukemia. Nonoperative management of avascular necrosis failed, and the patient was treated with bilateral total hip arthroplasty. The patient was followed at regular intervals and had slow eccentric polyethylene wear during a 10-year period. After 10 years, the patient had accelerated wear, with femoral and acetabular bone changes as a result of Oxinium and ultrahigh-molecular-weight polyethylene wear during a 6-month period. This article highlights the unusual accelerated bone changes that occurred as a result of Oxinium wear particles.

  13. Degradation of titanium drillpipe from corrosion and wear

    Energy Technology Data Exchange (ETDEWEB)

    Ferg, T.E.; Aldrich, C.S. (Colorado School of Mines, Golden, CO (United States)); Craig, B.D. (Metallurgical Consultants Inc., Montebello (United States))

    1993-06-01

    Drilling deeper than 35,000 ft is limited by the extreme hook loads of steel drillpipe and temperature constraints of aluminum drillpipe. Titanium Alloys Ti-6Al-4V and Beta C have been proposed for use in drillpipe for wells deeper than 35,000 ft because of their high strength/weight ratios, superior high-temperature corrosion resistance, and thermal stability. Their suitability in drilling environments, however, has not been evaluated. To determine the corrosion and wear characteristics of two types of titanium-alloy drillpipe under dogleg conditions, a test cell was constructed to test titanium drillpipe joints in contact with API Spec. 5CT Grade P-110 casing in different drilling muds. Titanium-alloy pipe and Grade P-110 casing wear rates were measured, and tests showed that both titanium-alloy pipes exhibited much greater wear than did steel drillpipe in water-based mud under the same conditions. Test data showed that the total wear rate of Alloys Ti-6Al-4V and Beta C in a drilling environment is a combination of mechanical wear and corrosion.

  14. Wear resistance of experimental titanium alloys for dental applications.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Rodrigues, Renata Cristina Silveira; Claro, Ana Paula Rosifini Alves; da Gloria Chiarello de Mattos, Maria; Ribeiro, Ricardo Faria

    2011-11-01

    The present study evaluated microstructure, microhardness and wear resistance of experimental titanium alloys containing zirconium and tantalum. Alloys were melted in arc melting furnace according to the following compositions: Ti-5Zr, Ti-5Ta and Ti-5Ta-5Zr (%wt). Hemispheres and disks were obtained from wax patterns that were invested and cast by plasma. Microstructures were evaluated using optical microscopy and X-ray diffraction (XRD) analysis and also Vickers microhardness was measured. Hemispherical samples and disks were used for 2-body wear tests, performed by repeated grinding of the samples. Wear resistance was assessed as height loss after 40,000 cycles. The data were compared using ANOVA and post-hoc Tukey test. Ti-5Zr presented a Widmanstätten structure and the identified phases were α and α' while Ti-5Ta and Ti-5Ta-5Zr presented α, β, α' and α" phases, but the former presented a lamellar structure, and the other, acicular. The microhardness of Ti-5Zr was significantly greater than other materials and cp Ti presented wear resistance significantly lower than experimental alloys. It was concluded that wear resistance was improved when adding Ta and Zr to titanium and Zr increased microhardness of Ti-5Zr alloy.

  15. A new production technique for wear resistant ring-hammers

    Directory of Open Access Journals (Sweden)

    Li Shifeng

    2011-11-01

    Full Text Available Based on a great number of laboratory experiments, a new technique has been developed for producing wear resistant ring-hammers. In this technology, lost foam casting with iron sand was combined to make mold; a special alloy was used to inoculate the molten steel, and proper heat treatment was used to further improve mechanical properties of wear resistant ring-hammers. The influence of this new production technology on the microstructure and mechanical properties of wear resistant ring-hammers was studied. Results show that iron sand molding, having the inherent characteristic of sand molding, changes the type of metallic compounds, refines crystal grains and increases the fineness of microstructure. Practical experience verified that the properties of the ring-hammers produced with this new technique are as follows: tensile strength (Rm 720 MPa, impact toughness (ak > 210 J•cm-2 and hardness > 200 HB. After water quenching from 1,080℃ (holding for 4 h and tempering at 320℃ for 3 h, the best wear resistance is obtained, and the wear resistance is 1.6 times higher than that of common high manganese ring-hammers.

  16. Agave Chewing and Dental Wear: Evidence from Quids.

    Directory of Open Access Journals (Sweden)

    Emily E Hammerl

    Full Text Available Agave quid chewing is examined as a potential contributing behavior to hunter-gatherer dental wear. It has previously been hypothesized that the contribution of Agave quid chewing to dental wear would be observed in communities wherever phytolith-rich desert succulents were part of subsistence. Previous analysis of coprolites from a prehistoric agricultural site, La Cueva de los Muertos Chiquitos in Durango, Mexico, showed that Agave was a consistent part of a diverse diet. Therefore, quids recovered at this site ought to be useful materials to test the hypothesis that dental wear was related to desert succulent consumption. The quids recovered from the site were found to be largely derived from chewing Agave. In this study, the quids were found to be especially rich in phytoliths, and analysis of dental casts made from impressions left in the quids revealed flat wear and dental attrition similar to that of Agave-reliant hunter-gatherers. Based on evidence obtained from the analysis of quids, taken in combination with results from previous studies, it is determined that Agave quid chewing was a likely contributing factor to dental wear in this population. As such, our method provides an additional avenue of dental research in areas where quids are present.

  17. Agave Chewing and Dental Wear: Evidence from Quids.

    Science.gov (United States)

    Hammerl, Emily E; Baier, Melissa A; Reinhard, Karl J

    2015-01-01

    Agave quid chewing is examined as a potential contributing behavior to hunter-gatherer dental wear. It has previously been hypothesized that the contribution of Agave quid chewing to dental wear would be observed in communities wherever phytolith-rich desert succulents were part of subsistence. Previous analysis of coprolites from a prehistoric agricultural site, La Cueva de los Muertos Chiquitos in Durango, Mexico, showed that Agave was a consistent part of a diverse diet. Therefore, quids recovered at this site ought to be useful materials to test the hypothesis that dental wear was related to desert succulent consumption. The quids recovered from the site were found to be largely derived from chewing Agave. In this study, the quids were found to be especially rich in phytoliths, and analysis of dental casts made from impressions left in the quids revealed flat wear and dental attrition similar to that of Agave-reliant hunter-gatherers. Based on evidence obtained from the analysis of quids, taken in combination with results from previous studies, it is determined that Agave quid chewing was a likely contributing factor to dental wear in this population. As such, our method provides an additional avenue of dental research in areas where quids are present.

  18. Testing of a Fiber Optic Wear, Erosion and Regression Sensor

    Science.gov (United States)

    Korman, Valentin; Polzin, Kurt A.

    2011-01-01

    The nature of the physical processes and harsh environments associated with erosion and wear in propulsion environments makes their measurement and real-time rate quantification difficult. A fiber optic sensor capable of determining the wear (regression, erosion, ablation) associated with these environments has been developed and tested in a number of different applications to validate the technique. The sensor consists of two fiber optics that have differing attenuation coefficients and transmit light to detectors. The ratio of the two measured intensities can be correlated to the lengths of the fiber optic lines, and if the fibers and the host parent material in which they are embedded wear at the same rate the remaining length of fiber provides a real-time measure of the wear process. Testing in several disparate situations has been performed, with the data exhibiting excellent qualitative agreement with the theoretical description of the process and when a separate calibrated regression measurement is available good quantitative agreement is obtained as well. The light collected by the fibers can also be used to optically obtain the spectra and measure the internal temperature of the wear layer.

  19. On the Friction and Wear Behaviors of Dental Machinable Porcelain

    Institute of Scientific and Technical Information of China (English)

    YU Hai-yang; ZHOU Zhong-rong; CAI Zhen-Bing

    2004-01-01

    In order to well design tribosystems of dental CAD-CAM restorations, an understanding of the tribological mechanisms of dental machinable porcelain are essential. The friction and wear behavior of new generation industrially prefabricated Cerec Vitablocs Mark Ⅱ against uniform Si3N4 ball has been performed using a small amplitude reciprocating apparatus under simulating oral conditions. The loads of 10-40 N, reciprocating amplitudes of 100-500 μm, frequencies of 1-4 Hz and two lubrications (no / artificial saliva lubrication) were selected. Tests lasting up to 10 000 cycles were conducted. The results show that Cerec Vitablocs Mark Ⅱ record a friction coefficient of 0.55-0.84. Artificial saliva plays a lubricant effect during wear process. Among three parameters of the test on friction coefficient and wear depth of dental machinable porcelains, the load effect is prominent. Abrasive wear is the main wear mechanism, but brittle cracks and delamination are more popular especially under unlubricated friction.

  20. On the Friction and Wear Behaviors of Dental Machinable Porcelain

    Institute of Scientific and Technical Information of China (English)

    YUHai-yang; ZHOUZhong-rong; CAIZhen-Bing

    2004-01-01

    In order to well design tribosystems of dental CAD-CAM restorations, an understanding of the tribological mechanisms of dental machinable porcelain are essential. The friction and wear behavior of new generation industrially prefabricated Cerec Vitablocs Mark II against uniform Si3N4ball has been performed using a small amplitude reciprocating apparatus under simulating oral conditions. The loads of 10-40N, reciprocating amplitudes of 100-500μm, frequencies of 1-4Hz and two lubrications (no / artificial saliva lubrication) were selected. Tests lasting up to 10 000 cycles were conducted. The results show that Cerec Vitablocs Mark Ⅱ record a friction coefficient of 0.55-0.84. Artificial saliva plays a lubricant effect during wear process. Among three parameters of the test on friction coefficient and wear depth of dental machinable porcelains, the load effect is prominent. Abrasive wear is the main wear mechanism, but brittle cracks and delamination are more popular especially under unlubricated friction.

  1. Manganese steel in impact wear testing; Manganhartstahl in Stossverschleisstest

    Energy Technology Data Exchange (ETDEWEB)

    Patzelt, B.; Hemmann, U.; Deters, L. [Magdeburg Univ. (Germany). Inst. fuer Maschinenkonstruktion

    2000-12-01

    Beating arms in impact crushers show high wear. In order to simulate the process of the mainly occuring impact wear, experimental investigations with a special test device were carried out. With this 11 different charges of manganese steel differing in their chemical composition were tested. The different chemical composition of the charges led to different results concerning the wear resistance. A significant interrelationship between wear resistance and macro-hardness of the charges of the manganese steel could be detected. With a faster rotor speed a considerable increase of wear could be determined as well. Microscopical investigations on worn test pieces exhibit a typical embedding of small particles of concrete into the metal matrix. (orig.) [German] Die Schlagleisten in Prallbrechern unterliegen einen hohen Verschleiss. Um den Prozess des hauptsaechlich auftretenden Stossverschleisses zu simulieren, wurden Modelluntersuchungen mit einer speziellen Pruefeinrichtung durchgefuehrt. Dabei konnten 11 verschiedene Chargen von Manganhartstahl, die sich im wesentlichen in ihrer chemischen Zusammensetzung unterschieden, untersucht werden. Die unterschiedliche chemische Zusammensetzung der einzelnen Chargen fuehrte zu unterschiedlichen Ergebnissen hinsichtlich der Verschleissbestaendigkeit der einzelnen Modellschlagleisten. Hierbei ist ein signifikanter Zusammenhang zwischen der Verschleissbestaendigkeit und der Makrohaerte der Manganhartstaehle zu erkennen. Die Umfangsgeschwindigkeit des Rotors der Pruefeinrichtung beeinflusst ebenfalls das Verschleissverhalten, und zwar fuehrte eine hoehere Umfangsgeschwindigkeit zu hoeherem Verschleiss. Mikroskopische Untersuchungen an geschaedigten Probekoerpern zeigten ein Einbetten von kleinsten Partikeln aus Beton im oberflaechennahen Stoffbereich der Metallmatrix. (orig.)

  2. Wear mechanism of electrodeposited amorphous Ni-Fe-P alloys

    Institute of Scientific and Technical Information of China (English)

    高诚辉; 赵源

    2004-01-01

    The wear mechanism of amorphous Ni-Fe-P coating was discussed. The wear resistance of the amor phous Ni-Fe-P coatings was tested on a Timken wear apparatus, and the wear track of the amorphous Ni-Fe-P coat ings as-deposited and heated at various temperatures was observed by SEM. The results show that the wear resistthe coating will change with the heating temperature increasing from pitting+plowing at 200 ℃ to pitting at 400 ℃,and to plowing at 600 ℃. The pits on the worn surface of the amorphous Ni-Fe-P coating result from the tribo-fatigue fracture. The cracks of spalling initiate at pits and propagate at certain angle with the sliding direction on sur face, and then extend into sub-surface along the poor P layers or the interface between layers. Finally under repeated action of the stress in the rubbing process the cracks meet and the debris forms. The generation of the pits and spal-ling is related with the internal stress, brittleness and layer structure of the amorphous Ni-Fe-P coating.

  3. Point Lepreau primary heat transport pump wear ring cracking

    Energy Technology Data Exchange (ETDEWEB)

    Licina, G. [Structural Integrity Associates, Inc., San Jose, California (United States); Rankin, B. [Point Lepreau Nuclear Generating Station, Fredericton, New Brunswick (Canada)

    2011-07-01

    The number 3 Primary Heat Transport (PHT) pump from Point Lepreau Nuclear Generating Station (Point Lepreau) was disassembled after more than 30 years of service for inspection during station refurbishment. The disassembly and inspection were performed to provide assurance of continued satisfactory operation during life extension. The inspection revealed cracks in the wear ring, at and near the tack welds (Type 309 stainless steel weld metal) at the cap screws that attach the Type 420 stainless steel wear ring to the body of the pump. Investigative work consisted of on-site PT and replication of the microstructure at the surface of the wear ring, subsequent impressions of two crack faces, and hardness determinations. This paper describes the investigative work and conclusions associated with resolution of the following questions: 1. What is the most likely cause of the cracking? 2. Will the cracks propagate within the base metal of the wear ring? 3. If propagation is possible, what is the risk of cracks intersecting, such that a piece of metal could become dislodged? Question number 3 has clear ramifications with respect to foreign material entering and damaging a nuclear fuel-containing pressure tube. There are also questions associated with extent of condition, specifically, whether other PHT pumps may have similar or worse cracking and whether such cracks will grow. Results will be applied to wear rings in other PHT pumps at Point Lepreau and are likely to be applicable to similar components in other CANDU PHT pumps. (author)

  4. Characterization of polyethylene wear particle: The impact of methodology.

    Science.gov (United States)

    Schröder, Christian; Reinders, Jörn; Zietz, Carmen; Utzschneider, Sandra; Bader, Rainer; Kretzer, J Philippe

    2013-12-01

    Due to the prevalence of problems caused by wear particles, the reduced durability of total joint replacements is well documented. The characterization of wear debris enables the size and morphology of these wear particles to be measured and provides an assessment of the biological response in vivo. However, the impact of different methodologies of particle analysis is not yet clear. Hence, the aim of this investigation was to analyze the influence of different particle characterization methods performed by three research centers within the scope of a "round robin test". To obtain knowledge about possible pitfalls, single steps of the particle characterization process (storage, pore size of the filter, coating durations by gold sputtering and scanning electron microscopy (SEM) magnification) were analyzed. The round robin test showed significant differences between the research groups, especially for the morphology of the particles. The SEM magnification was identified as having the greatest influence on the size and shape of the particles, followed by the storage conditions of the wear particle containing lubricant. Gold sputter coating and filter pore size also exhibit significant effects. However, even though they are statistically significant, it should be emphasized that the differences are small. In conclusion, particle characterization is a complex analytical method with a multiplicity of influencing factors. It becomes apparent that a comparison of wear particle results between different research groups is challenging.

  5. 3D Simulation Modeling of the Tooth Wear Process.

    Science.gov (United States)

    Dai, Ning; Hu, Jian; Liu, Hao

    2015-01-01

    Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function) implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation.

  6. 3D Simulation Modeling of the Tooth Wear Process.

    Directory of Open Access Journals (Sweden)

    Ning Dai

    Full Text Available Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation.

  7. Engine valve and seat insert wear study with a simulator

    Institute of Scientific and Technical Information of China (English)

    Y.S.Wang; S.Narasimhan

    2001-01-01

    The demands on higher performance and the increasing use of alternative fuels chal-lenge engine valves now with greater wear problems than before. A seat wear simulator was builtto evaluate the compatibility and wear of valve and seat insert. The rig test results have been suc-cessfully correlated with engine test results. In this study, intake valves made from Sil 1 materialwere treated with salt bath nitride processes and tested against six different insert materials. Wearresistance of these combinations was ranked and compared to the Sil 1 valve without nitriding.The test results demonstrate that nitriding improved valve seat wear resistance. In the total valveseat recession ranking, the combination of nitrided Sil 1 valve against T 400 insert exhibited theleast total recession among the nineteen combinations of valve and insert tested. The results indi-cate that the valve seat wear mechanisms are a complex combination of adhesion and shearstrain. The nitrides in the compound layer of nitrided valves gave strong atomic bonding, higherhardness, compressive residual stresses, and possible low friction, thus resulted in the superiorwear performance.

  8. Abrasive wear property of laser melting/deposited Ti2Ni/TiNi intermetallic alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A wear resistant intermetallic alloy consisting of TiNi primary dendrites and Ti2Ni matrix was fabricated by the laser melting deposition manufacturing process. Wear resistance of Ti2Ni/TiNi alloy was evaluated on an abrasive wear tester at room temperature under the different loads. The results show that the intermetallic alloy suffers more abrasive wear attack under low wear test load of 7, 13 and 25 N than high-chromium cast-iron. However, the intermetallic alloy exhibits better wear resistance under wear test load of 49 N. Abrasive wear of the laser melting deposition Ti2Ni/TiNi alloy is governed by micro-cutting and plowing.Pseudoelasticity of TiNi plays an active role in contributing to abrasive wear resistance.

  9. Effect of Polyethylene Crosslinking and Bearing Design on Wear of Unicompartmental Arthroplasty.

    Science.gov (United States)

    Netter, Jonathan; Hermida, Juan C; D'Alessio, Jerry; Kester, Mark; D'Lima, Darryl D

    2015-08-01

    Wear and polyethylene damage continue to be important factors affecting outcomes of unicompartmental knee arthroplasty. We compared two design rationales for unicompartmental arthroplasty: fully congruent mobile bearings; or moderately conforming fixed bearings using experimental and computational wear simulation. Experimental wear rates were 3.89 (±0.12) mg/million cycles for the highly crosslinked Triathlon PKR fixed bearing compared to 18.35 (±0.19) mg/million cycles for the low crosslinked Oxford mobile bearing. Finite element analysis was used to calculate the effect of crosslinking and backside wear. Increase in polyethylene crosslinking reduced wear by 68% while backside wear comprised 46% of the total wear in the mobile bearing. Increasing conformity may not be the sole predictor of wear performance and highly crosslinked fixed-bearing polyethylene insert can also provide high wear performance.

  10. Combining Diagnosis of the Casing and Tooljoint Wear in Mud Fluid While Drilling

    Institute of Scientific and Technical Information of China (English)

    樊建春; 张来斌; 温东; 余磊

    2004-01-01

    A ground monitoring system was developed to diagnose casing and tooljoint wear in a well during drilling by combining the analysis of wear debris with detection of the tooljoints.The result shows that the wear debris concentration in the circulating drilling mud in a well reflects the total wear rate of the tribo-elements in the well, while the wear detection of a tooljoint can indicate its wear loss between two contiguous times of drill-pipe lifting.A diagnosis method that integrates the two types of information was developed to identify severe wear regions in well casing.Theoretical analyses and field test show that the severe casing wear region can be located relatively accurately by the integrated method.This method presents a new ground casing wear diagnosis approach with good real-time results.

  11. Wear Modalities and Mechanisms of the Mining Non-asbestos Composite Brake Material

    Science.gov (United States)

    Bao, Jiusheng; Yin, Yan; Zhu, Zhencai; Tong, Minming; Lu, Yuhao; Peng, Yuxing

    2013-08-01

    The mining brake material is generally made of composite materials and its wear has important influences on the braking performance of disc brakes. In order to improve the braking reliability of mine hoisters, this paper did some tribological investigations on the mining brake material to reveal its wear modalities and mechanisms. The mining non-asbestos brake shoe and 16Mn steel were selected as braking pairs and tested on a pad-on-disc friction tester. And a SEM was used to observe the worn surface of the brake shoe. It is shown that the non-asbestos brake material has mainly five wear modalities: adhesive wear, abrasive wear, cutting wear, fatigue wear and high heat wear. At the front period of a single braking the wear modality is mainly composed of some light mechanical wear such as abrasive, cutting and point adhesive. With the temperature rising at the back period it transforms to some heavy mechanical wear such as piece adhesive and fatigue. While in several repeated brakings once the surface temperature rises beyond the thermal-decomposition point of the bonding material, the strong destructive high heat wear takes leading roles on the surface. And a phenomenon called friction catastrophe (FC) occurs easily, which as a result causes a braking failure. It is considered that the friction heat has important influences on the wear modalities of the brake material. And the reduction of friction heat must be an effective technical method for decreasing wear and avoiding braking failures.

  12. Wear testing of moderate activities of daily living using in vivo measured knee joint loading.

    Directory of Open Access Journals (Sweden)

    Jörn Reinders

    Full Text Available Resumption of daily living activities is a basic expectation for patients provided with total knee replacements. However, there is a lack of knowledge regarding the impact of different activities on the wear performance. In this study the wear performance under application of different daily activities has been analyzed. In vivo load data for walking, walking downstairs/upstairs, sitting down/standing up, and cycling (50 W & 120 W has been standardized for wear testing. Wear testing of each activity was carried out on a knee wear simulator. Additionally, ISO walking was tested for reasons of comparison. Wear was assessed gravimetrically and wear particles were analyzed. In vivo walking produced the highest overall wear rates, which were determined to be three times higher than ISO walking. Moderate wear rates were determined for walking upstairs and downstairs. Low wear rates were determined for standing up/sitting down and cycling at power levels of 50 W and 120 W. The largest wear particles were observed for cycling. Walking based on in vivo data has been shown to be the most wear-relevant activity. Highly demanding activities (stair climbing produced considerably less wear. Taking into account the expected number of loads, low-impact activities like cycling may have a greater impact on articular wear than highly demanding activities.

  13. Advanced Wear Simulation for Bulk Metal Forming Processes

    Directory of Open Access Journals (Sweden)

    Behrens Bernd-Arno

    2016-01-01

    Full Text Available In the recent decades the finite element method has become an essential tool for the cost-efficient virtual process design in the metal forming sector in order to counter the constantly increasing quality standards, particularly from the automotive industry as well as intensified international competition in the forging industry. An optimized process design taking precise tool wear prediction into account is a way to increase the cost-efficiency of the bulk metal forming processes. The main objective of the work presented in this paper is a modelling algorithm, which allows predicting die wear with respect to a geometry update during the forming simulation. Changes in the contact area caused by geometry update lead to the different die wear distribution. It primarily concerns the die areas, which undergo high thermal and mechanical loads.

  14. Aesthetic rehabilitation in a patient with tooth wear

    Directory of Open Access Journals (Sweden)

    Haroon Rashid

    2012-01-01

    Full Text Available This case report sheds light upon the procedural treatment of aesthetic oral rehabilitation in patients with tooth wear so that not only a specialist but also a general dental practitioner can easily tackle cases of this caliber. In this case report, the treatment of a 58-year-old man with aesthetics concerns, tooth wear, and sensitivity in anterior teeth is discussed. The need for a stabilizing splint, crown lengthening, and the provisioning of partial dentures in the upper and lower arches were all part of the treatment protocol in this case. The prevalence of tooth wear and the aesthetic demands of patients have increased in our society nowadays. When both of these problems are encountered together in the dental practice, strict treatment planning is needed to achieve success.

  15. Sliding contacts on printed circuit boards and wear behavior

    Science.gov (United States)

    Le Solleu, J.-P.

    2010-04-01

    Automotive suppliers use since decades printed circuit boards (PCB) gold plating pads, as direct contact interface for low current sliding contacts. Several gold plating processes are available on the market, providing various wear behaviour. Some specific galvanic hard gold (AuCo or AuNi). plating was developed on PCB's. This specific plating generates extra costs due to the material quantity and also the process complexity. In a cost driven industry, the challenge is to use a standard low cost PCB for systems requesting high reliability performances. After a brief overview of standard PCB manufacturing processes and especially gold plating processes, the global experimental results of wear behaviour of three different gold plating technologies will be exposed and an explanation of the correlation between surface key parameters and wear out will be provided.

  16. Wear fault diagnosis of an emulsion pump crank bearing

    Institute of Scientific and Technical Information of China (English)

    HAN Xiao-ming; DU Chang-long; ZHANG Yong-zhong; TIE Zhan-xu

    2008-01-01

    The total load on a crank bearing was calculated by performing a load analysis of the crank connecting rod mechanism.The Reynolds equation for hydrodynamic lubrication of the crank bearing was established at the Reynolds boundary condition and was then solved using the Holland method. From this the regular track of the bearing axis was obtained. As the crank bearing gradually wears the eccentricity ratio corresponding to the minimum oil film thickness increases gradually. The oil-bound film eventually breaks down, which allows friction and collision between the metal surfaces of the crank pin and the bearing. The rigid impact leads to excitation of high frequency vibrations at the natural frequencies of the connecting rod. The experiments show that the wear condition of the crank bearing can be identified correctly through the vibration signature at the natural frequencies of the connecting rod. The degree of wear can be predicted accurately through the energy content of the high frequency bands.

  17. Friction Induced Wear of Rapid Prototyping Generated Materials: A Review

    Directory of Open Access Journals (Sweden)

    A. Tsouknidas

    2011-01-01

    Full Text Available Additive manufacturing has been introduced in the early 80s and has gained importance as a manufacturing process ever since. Even though the inception of the implicated processes predominantly focused on prototyping purposes, during the last years rapid prototyping (RP has emerged as a key enabling technology for the fabrication of highly customized, functionally gradient materials. This paper reviews friction-related wear phenomena and the corresponding deterioration mechanisms of RP-generated components as well as the potential of improving the implicated materials' wear resistance without significantly altering the process itself. The paper briefly introduces the concept of RP technologies and the implicated materials, as a premises to the process-dependent wear progression of the generated components for various degeneration scenarios (dry sliding, fretting, etc..

  18. Wear resistance of a metal surface modified with minerals

    Science.gov (United States)

    Kislov, S. V.; Kislov, V. G.; Balasch, P. V.; Skazochkin, A. V.; Bondarenko, G. G.; Tikhonov, A. N.

    2016-02-01

    The article describes the advantages of the new technology of mineral coating of metal products for the friction pair of mechanical systems. It presents the research results of the wear rate of the samples made of 12X13 steel (X12Cr13) with mineral layers, in the experiments with a piston ring sliding inside a cylinder liner with grease. The wear rate of the samples with mineral layers is lower almost by two factors than that of the samples made of grey foundry iron and untreated samples. As the result of slip/rolling abrasion tests of parts with mineral layers under conditions of high contact pressure, a suggestion was made concerning probable mechanics of surface wear.

  19. Dry sliding wear of Ni alloyed austempered ductile iron

    Directory of Open Access Journals (Sweden)

    E. Akbarzadeh Chiniforush

    2016-09-01

    Full Text Available Measurements of dry sliding wear are presented for ductile irons with composition Fe-3.56C-2.67Si-0.25Mo-0.5Cu and Ni contents of 0.8 and 1.5 in wt.% with applied loads of 50, 100 and 150 N for austempering temperatures of 270, 320, and 370 °C after austenitizing at 870 °C for 120 min. The mechanical property measurements show that the grades of the ASTM 897M: 1990 Standard can be satisfied for the selected austempering conditions. The results show that wear resistance is independent of austempering temperature with an applied load of 50 N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150 N. Observations indicate that wear is due to subsurface fatigue with cracks nucleated at deformed graphite nodules.

  20. Corrosive wear behavior of 2014 and 6061 aluminum alloy composites

    Energy Technology Data Exchange (ETDEWEB)

    Varma, S.K.; Andrews, S.; Vasquez, G. [Univ. of Texas, El Paso, TX (United States). Dept. of Metallurgical and Materials Engineering

    1999-02-01

    Alloys of 2014 and 6061 aluminum reinforced with 0.1 volume fraction of alumina particles (VFAP) were subjected to impact scratching during a corrosive wear process. The transient currents generated due to the impact were measured in the two composites as well as in their respective monoliths. The effect of solutionizing time on the transient currents was correlated to the near surface microstructures, scratch morphology, concentration of quenched-in vacancies, and changes in grain sizes. It was observed that the transient current values increase with an increase in solutionizing time, indicating that the corrosive wear behavior is not strongly affected by the grain boundaries. However, a combination of pitting and the galvanic corrosion may account for the typical corrosive wear behavior exhibited by the alloys and the composites of this study.

  1. The Wear Behavior of HVOF Sprayed Near-Nanostructured WC-17%Ni(80/20)Cr Coatings in Dry and Slurry Wear Conditions

    Science.gov (United States)

    Ben Mahmud, Tarek A.; Atieh, Anas M.; Khan, Tahir I.

    2017-07-01

    The ability to deposit nanostructured feedstock by using high-velocity oxygen-fuel (HVOF) spray offers potential improvements in coating hardness, wear resistance and toughness for applications in the oil sands industry. In this study, the wear behavior of a near-nanostructured coating was compared under dry and slurry abrasive wear test using an uncoated AISI-1018 low-carbon steel substrate as a reference. The coating microstructures were analyzed in the as-sprayed, dry and slurry test conditions using scanning electron microscopy, x-ray diffraction and microhardness measurements. Wear behavior of the steel and coating surfaces were assessed using a pin-on-plate wear test under various loads. The results showed that a coating could be successfully deposited using the HVOF spraying technique and with retention of the near-nanosized WC dispersion within the coating structure. The wear rate under dry test conditions was greater for the steel and coating compared to tests performed under slurry conditions. Examination of the wear tracks revealed that the wear mechanism was different for the two test conditions. Wear in the dry test condition resulted from 2-body abrasion, while 3-body abrasion dominated wear in slurry conditions. The latter showed lower wear rates due to a lubricating effect of the oil.

  2. PMMA Third-Body Wear after Unicondylar Knee Arthroplasty Decuples the UHMWPE Wear Particle Generation In Vitro

    Directory of Open Access Journals (Sweden)

    Alexander Christoph Paulus

    2015-01-01

    Full Text Available Introduction. Overlooked polymethylmethacrylate after unicondylar knee arthroplasty can be a potential problem, since this might influence the generated wear particle size and morphology. The aim of this study was the analysis of polyethylene wear in a knee wear simulator for changes in size, morphology, and particle number after the addition of third-bodies. Material and Methods. Fixed bearing unicondylar knee prostheses (UKA were tested in a knee simulator for 5.0 million cycles. Following bone particles were added for 1.5 million cycles, followed by 1.5 million cycles with PMMA particles. A particle analysis by scanning electron microscopy of the lubricant after the cycles was performed. Size and morphology of the generated wear were characterized. Further, the number of particles per 1 million cycles was calculated for each group. Results. The particles of all groups were similar in size and shape. The number of particles in the PMMA group showed 10-fold higher values than in the bone and control group (PMMA: 10.251×1012; bone: 1.145×1012; control: 1.804 × 1012. Conclusion. The addition of bone or PMMA particles in terms of a third-body wear results in no change of particle size and morphology. PMMA third-bodies generated tenfold elevated particle numbers. This could favor an early aseptic loosening.

  3. Effects of rare earths on friction and wear characteristics of magnesium alloy AZ91D

    Institute of Scientific and Technical Information of China (English)

    祁庆琚; 刘勇兵; 杨晓红

    2003-01-01

    The influence of various rare-earth contents on the friction and wear characteristics of magnesium alloyAZ91D was studied. The results show that the wear resistance properties of rare-earth magnesium alloys are betterthan those of the matrix alloy under the testing conditions. Magnesium alloys undergo transition from mild wear tosevere wear. The addition of rare earths refines the structure of alloys, improves the comprehensive behaviors of themagnesium alloys, increases the stability of oxidation films on worn surfaces, enhances the loading ability of rare-earth magnesium alloys, and delays the transition from mild wear to severe wear effectively.

  4. Abrasive Wear Behavior of High Chromium Cast Iron and Hadfield Steel-- A Comparison

    Institute of Scientific and Technical Information of China (English)

    Mehdi Mazar Atabaki; Sajjad Jafari; Hassan Abdollah-pour

    2012-01-01

    Wear properties of two different crushers used for grinding raw materials of cement industry are compared using pin-on-disk wear test.The wear test was carried out with different loads on a pin.Abrasive wear behavior of two alloys was evaluated by comparing mass loss,wear resistance,microhardness and friction coefficient.The microstructure of the specimens was detected using optical microscope.The results showed that abrasive wear of high chromium cast iron is lower than that of Hadfield steel.Due to the presence of M7C3 carbides on the high chromium cast iron matrix,impact crushers exhibited higher friction coefficient

  5. Experimental study on wear failure course of gas-valve/valve-seat in engine

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yun-cai; YAN Hang-zhi

    2005-01-01

    The wear failure course of gas-valve/valve-seat in engine was investigated with a simulating tester. The results show that the failure of the contact conical surface is mainly caused by the elastic and plastic deformation and the fatigue micro-crack and spalling. The creep-deformation and corrosion atmosphere accelerated wear failure course at the high temperature. The wear failure course of the gas-valve/valve-seat in engine follows general wear rules of mechanical elements, but the rate of wear in the sharp wear stage is faster.

  6. Taxi driver seat belt wearing in Nanjing, China.

    Science.gov (United States)

    Routley, Virginia; Ozanne-Smith, Joan; Qin, Yu; Wu, Ming

    2009-01-01

    To determine and validate patterns of seat belt use and attitudes of taxi drivers on wearing a seat belt following national and provincial seat belt legislation in 2004-2005. Roadside daylight seat belt observation and interview survey methods were used, as well as observations from inside taxis during routine trips and a taxi driver focus group. The setting was Nanjing, Jiangsu Province, PR China in April of 2006 and 2007. Prevalence of seat belt use and attitudes to wearing a seat belt were determined, as were vehicle and driver characteristics, and comparisons with other motor-vehicle driver's seat belt use and attitudes. Taxi drivers interviewed were predominantly male and aged 30-39 years. They spent more hours per week in their vehicles and had more driving experience than other drivers. Over half (56.2%) of taxi drivers interviewed reported that they always wore seat belts, while observation of taxi drivers showed lower wearing rates (i.e., roadside observation was 43.8%, and observation from inside taxis was 36.2%). Belt tampering was a practice of 12-15% of taxi drivers. "Fine avoidance, safety, high speed and long trips" were given as important reasons for wearing and "feeling trapped and uncomfortable" for not wearing. Seat belt reminder signs in taxis were common (82.6% of taxis), but did not appear to impact on driver seat belt use. The four research methods found taxi drivers to have consistently low "correct wearing" rates. As in several other countries, taxi drivers are particularly resistant to seat belt use. Innovative strategies, including occupational health and safety approaches, may be required to achieve increased levels of seat belt use.

  7. INCREASING OF WEAR RESISTANCE OF THE GRAPHITIZED STEEL

    Directory of Open Access Journals (Sweden)

    I. V. Akimov

    2013-11-01

    Full Text Available Purpose. Graphitized steels are alloys, in which carbon is partly in form of graphite inclusions. Due to this such steels possess good antifriction properties, wear resistance, heat conductivity and a variety of other mechanical properties, which decently distinguish them from cast irons. However, such steels are not studied enough and practically are not used in mechanical engineering. Purpose of the work is the research of the possibility of wear resistance increase for graphitized steels in the conditions of metal-to-metal dry friction sliding to use them in the railway systems. Methodology. Graphitized hypoeutectoid, eutectoid and hypereutectoid steels have been used as a research material. Experimental alloys have been studied in the condition after thermal hardening. Hardness of alloys has been determined by the Vickers method. Wear resistance of steels has been studied in the conditions of metal-to-metal dry friction sliding with the use of МI-1 friction machine (disk to disk. Findings. Data, which allow assessing the wear resistance of experimental graphitized steels depending on carbon, silicon and copper content have been obtained in this work. The regression dependence obtained as a result of statistical processing of the experimental data allowed determining an optimal chemical content of the steel, which is characterized by high wear resistance. Originality. A dependence describing carbon, silicon and copper content on the specimen's weight loss during metal-to-metal dry friction tests has been obtained in the work. Practical value. The optimized content of the graphitized steel can be used for production of products working in the conditions of wear such as brake blocks of rolling stock, separators of high-speed bearings, dies and others.

  8. Wearing ambidextrous vinyl gloves does not impair manual dexterity.

    Science.gov (United States)

    Drabek, Tomas; Boucek, Charles D; Buffington, Charles W

    2013-01-01

    Universal precautions mandate that health care workers wear gloves to prevent the unintended spread of bloodborne pathogens. Gloves may affect manual dexterity, generally delaying task completion. Our previous study showed that wearing the wrong size latex surgical glove degraded manual dexterity. The use of non-sterile and non-latex gloves may limit certain risks and be more cost-effective. However, such gloves may produce different results. We hypothesized that ambidextrous vinyl examination gloves would degrade manual dexterity compared with bare hands. We studied 20 random subjects from a medical environment. Subjects performed a standard battery of Grooved Pegboard tasks while bare-handed, wearing ambidextrous non-sterile vinyl gloves that were their preferred size, a size too small, and a size too large. The order was randomized with a Latin Square design to minimize the effects of time, boredom, and fatigue on the subjects. Subjects were also invited to comment on the fit of different size gloves. Wearing vinyl gloves of both the preferred size and a size up or down failed to affect manual dexterity vs. bare hands on time to insert pegs, and pegs dropped during insertion or removal. In contrast, the time to remove pegs was reduced by wearing preferred size vinyl gloves compared with performing the task with bare hands (P<0.05). Subjects reported a generally poor fit in all sizes. Vinyl gloves that were too small caused significant hand discomfort. Vinyl gloves surprisingly do not degrade manual dexterity even when worn in ill-fitting sizes. Wearing a preferred size vinyl glove vs. bare hands may improve dexterity in selected tasks. Choosing a comfortable, large size seems the best strategy when the preferred size is unavailable. Thinner vinyl gloves may improve grip and may not degrade touch as much as latex surgical gloves and may thus represent a reasonable choice for selected tasks.

  9. Unexpected wear of an unicompartimental knee arthroplasty in oxidized zirconium.

    Science.gov (United States)

    Luyet, Anais; Fischer, Jean-François; Jolles, Brigitte M; Lunebourg, Alexandre

    2015-12-01

    Unicompartimental knee arthroplasty is a successful procedure for the treatment of localized osteoarthritis to one compartment of the knee with good long-term results. However, several modes of failure of unicompartimental knee arthroplasty have been described, namely aseptic or septic loosening, progression of disease, wear, and instability. Metallosis after unicompartimental knee arthroplasty is rarely reported and is most often related with polyethylene wear or break. We report on a case of rapid failure of unicompartimental knee arthroplasty in oxidized zirconium associated with metallosis secondary to the dislocation of the polyethylene.

  10. Industrial tribology tribosystems, friction, wear and surface engineering, lubrication

    CERN Document Server

    Mang, Theo; Bartels, Thorsten

    2010-01-01

    Integrating very interesting results from the most important R & D project ever made in Germany, this book offers a basic understanding of tribological systems and the latest developments in reduction of wear and energy consumption by tribological measures. This ready reference and handbook provides an analysis of the most important tribosystems using modern test equipment in laboratories and test fields, the latest results in material selection and wear protection by special coatings and surface engineering, as well as with lubrication and lubricants.This result is a quick introductio

  11. Wear Tests of a Potential Biolubricant for Orthopedic Biopolymers

    OpenAIRE

    Thompson, Martin; Hunt, Ben; Smith, Alan M.; Joyce, Thomas

    2015-01-01

    Most wear testing of orthopedic implant materials is undertaken with dilute bovine serum used as the lubricant. However, dilute bovine serum is different to the synovial fluid in which natural and artificial joints must operate. As part of a search for a lubricant which more closely resembles synovial fluid, a lubricant based on a mixture of sodium alginate and gellan gum, and which aimed to match the rheology of synovial fluid, was produced. It was employed in a wear test of ultra high mole...

  12. Wear Behaviour of Carbon Nanotubes Reinforced Nanocrystalline AA 4032 Composites

    Science.gov (United States)

    Senthil Saravanari, M. S.; Kumaresh Babu, S. P.; Sivaprasad, K.

    2016-09-01

    The present paper emphasizes the friction and wear properties of Carbon Nanotubes reinforced AA 4032 nanocomposites prepared by powder metallurgy technique. CNTs are multi-wall in nature and prepared by electric arc discharge method. Multi-walled CNTs are blended with AA 4032 elemental powders and compaction followed by sintering to get bulk nanocomposites. The strength of the composites has been evaluated by microhardness and the surface contact between the nanocomposites and EN 32 steel has been evaluated by Pin on disk tester. The results are proven that reinforcement of CNTs play a major role in the enhancement of hardness and wear.

  13. Changes in the Eye Microbiota Associated with Contact Lens Wearing

    OpenAIRE

    Hakdong Shin; Kenneth Price; Luong Albert; Jack Dodick; Lisa Park; Maria Gloria Dominguez-Bello

    2016-01-01

    ABSTRACT Wearing contact lenses has been identified as a risk factor for the development of eye conditions such as giant papillary conjunctivitis and keratitis. We hypothesized that wearing contact lenses is associated with changes in the ocular microbiota. We compared the bacterial communities of the conjunctiva and skin under the eye from 58 subjects and analyzed samples from 20 subjects (9 lens wearers and 11 non-lens wearers) taken at 3 time points using a 16S rRNA gene-based sequencing t...

  14. Bacterial populations on 30-night extended wear silicone hydrogel lenses.

    Science.gov (United States)

    Keay, L; Willcox, M D; Sweeney, D F; Morris, C A; Harmis, N; Corrigan, K; Holden, B A

    2001-01-01

    Ocular infection and inflammation during hydrogel lens extended wear is often associated with colonization of the lenses with bacteria. This study compares colonization of a high Dk silicone hydrogel contact lens (lotrafilcon A) worn on a 30-night extended wear basis to a low Dk HEMA-based lens (etafilcon A) worn on a 6-night extended wear schedule. The group wearing the low Dk/t soft contact lens (n = 63) replaced their lenses weekly and the group wearing high Dk/t soft contact lenses replaced their lenses monthly (n = 64). Lens allocation was assigned randomly at enrollment. Worn lenses, from one eye only, were collected aseptically and placed in sterile vials. Microbial growth on various media was enumerated and the number of colony forming units (cfu) per lens was calculated in categories of normal ocular microbiota (such as coagulase-negative staphylococci and Propionibacterium spp.) and known ocular pathogens (such as Staphylococcus aureus and gram-negative bacteria). The proportion of samples colonized with these bacteria and the extent of colonization were compared between the two groups. The proportion of sterile lenses was calculated, and the types of bacteria on each lens group were compared. No differences between the low and high Dk/t Soft contact lens groups were observed in the proportion of lenses colonized by Propionibacterium spp. (48% vs 43%, P = 0.4) or coagulase-negative staphylococci (47% vs 54%, P = 0.2). Similarly, no differences were found for lenses colonized by S. aureus (0% vs 2%, P = 0.1) or gram-negative bacteria (3% vs 2%, P = 0.8). The types of bacteria isolated from the high and low Dk/t lenses were similar. There were no differences in the number of sterile samples (28% vs 27%, P = 0.8) from each group. These findings suggest that high Dk/t silicone hydrogel materials are colonized by similar numbers and types of microorganisms during extended wear compared to HEMA-based material. Most lenses were colonized by commensal bacteria

  15. Towards Phosphorus Free Ionic Liquid Anti-Wear Lubricant Additives

    Directory of Open Access Journals (Sweden)

    Anthony E. Somers

    2016-06-01

    Full Text Available The development of improved anti-wear additives would enable the use of lower viscosity oils that would lead to improved efficiency. Ionic liquids have the potential to be this type of new anti-wear additive. However, currently the best performing ionic liquids that are miscible in non-polar base oils, the phosphonium phosphates, contain phosphorus on both the cation and anion. Manufacturers are seeking to reduce the presence of phosphorus in oils. Here, as a first step towards phosphorus-free anti-wear additives, we have investigated ionic liquids similar to the phosphonium phosphates but having either a phosphorus-free cation or anion. Two quaternary ammonium phosphates (N6,6,6,14(BEHP and (N8,8,8,8(BEHP and a phosphonium silyl-sulfonate (P6,6,6,14(SSi were compared to a phosphonium phosphate (P6,6,6,14(BEHP and a traditional zinc dithiophosphate (ZDDP as anti-wear additives in mineral oil. The change from a phosphonium to a quaternary ammonium cation drastically reduced the miscibility of the Ionic liquid (IL in the oil, while the change to a smaller silicon containing anion also resulted in limited miscibility. For the pin-on-disk wear test conditions used here none of the ionic liquids outperformed the ZDDP except the (P6,6,6,14(BEHP at a relatively high loading of 0.10 mol·kg−1 (approximately 8 wt%. At a more moderate loading of 0.025 mol·kg−1 the (P6,6,6,14(SSi was the best performing ionic liquid by a significant amount, reducing the wear to 44% of the neat mineral oil, while the ZDDP reduced the wear to 25% of the mineral oil value. Electron microscopy and energy dispersive X-ray spectroscopy showed that the presence of a silicon containing tribofilm was responsible for this protective behaviour, suggesting that silicon containing ionic liquids should be further investigated as anti-wear additives for oils.

  16. Engineering wear-resistant surfaces in automotive aluminum

    Science.gov (United States)

    Kavorkijan, V.

    2003-02-01

    Inadequate wear resistance and low seizure loads prevent the direct use of aluminum alloys in automotive parts subject to intensive friction combined with high thermal and mechanical loading, such as brake discs, pistons, and cylinder liners. To enable the use of aluminum alloys in the production of automotive brake discs and other wear-resistant products, the insertion of a monolithic friction cladding rather than surface coating has been considered in this work. Three experimental approaches, two based on the pressure-less infiltration of porous ceramic preforms and one based on the subsequent hot rolling of aluminum and metal-matrix composite strips, are currently under investigation.

  17. Huge pelvic mass secondary to wear debris causing ureteral obstruction.

    Science.gov (United States)

    Hananouchi, Takehito; Saito, Masanobu; Nakamura, Nobuo; Yamamoto, Tetsuya; Yonenobu, Kazuo

    2005-10-01

    We report an unusual granulomatous reaction of wear debris that produced a huge pelvic mass causing ureteral obstruction. A 72-year-old woman, who received a cemented total hip arthroplasty 30 years ago, was referred to the department of gynecology for examination of a pelvic mass. A computed tomography scan revealed a huge homogenous mass, measuring approximately 20 x 16 x 12 cm, including extensive osteolysis of the left pelvis around the acetabular component. Intravenous pyelogram revealed complete obstruction of the left ureter resulting in hydronephrosis of the left kidney. Histological examination from the biopsy specimen detected polyethylene wear debris in the mass.

  18. Experimental Research on the Determination of the Coefficient of Sliding Wear under Iron Ore Handling Conditions

    Directory of Open Access Journals (Sweden)

    G. Chen

    2017-09-01

    Full Text Available The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is beneficial to the efficient maintenance of worn areas. Archard’s equation provides a theoretical solution to predict wear volume. To use Archard’s equation, the coefficient of sliding wear must be determined. To our best knowledge, the coefficient of sliding wear for iron ore handling conditions has not yet been determined. In this research, using a pin-on-disk tribometer, the coefficients of sliding wear for both Sishen particles and mild steel are determined with regard to iron ore handling conditions. Both naturally irregular and spherical shapes of particles are used to estimate average values of wear rate. Moreover, the hardness and inner structures of Sishen particles are examined, which adds the evidence of the interpretation of wear results. It is concluded that the coefficients of sliding wear can vary largely for both Sishen particle and mild steel. The wear rate decreases from transient- to steady-state. The average coefficient of sliding wear is capable of predicting wear with respect to long distances at the steady-state. Two types of sliding friction are distinguished. In addition, it is found that the temperature rise of the friction pairs has negligible influence on wear rate.

  19. Relationship between cusp size and occlusal wear pattern in Neanderthal and Homo sapiens first maxillary molars.

    Science.gov (United States)

    Fiorenza, Luca; Benazzi, Stefano; Viola, Bence; Kullmer, Ottmar; Schrenk, Friedemann

    2011-03-01

    Tooth wear studies in mammals have highlighted the relationship between wear facets (attritional areas produced during occlusion by the contact between opposing teeth) and physical properties of the ingested food. However, little is known about the influence of tooth morphology on the formation of occlusal wear facets. We analyzed the occlusal wear patterns of first maxillary molars (M(1) s) in Neanderthals, early Homo sapiens, and contemporary modern humans. We applied a virtual method to analyze wear facets on the crown surface of three-dimensional digital models. Absolute and relative wear facet areas are compared with cusp area and cusp height. Although the development of wear facets partially follows the cusp pattern, the results obtained from the between-group comparisons do not reflect the cusp size differences characterizing these groups. In particular, the wear facets developed along the slopes of the most discriminate cusp between Neanderthals and Homo sapiens (hypocone) do not display any significant difference. Moreover, no correlations have been found between cusp size and wear facet areas (with the exception of the modern sample) and between cusp height and wear facet areas. Our results suggest that cusp size is only weakly related to the formation of the occlusal wear facets. Other factors, such as, diet, food processing, environmental abrasiveness, and nondietary habits are probably more important for the development and enlargement of wear facets, corroborating the hypotheses suggested from previous dental wear studies.

  20. Milling tool wear diagnosis by feed motor current signal using an artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Khajavi, Mehrdad Nouri; Nasernia, Ebrahim; Rostaghi, Mostafa [Dept. of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of)

    2016-11-15

    In this paper, a Multi-layer perceptron (MLP) neural network was used to predict tool wear in face milling. For this purpose, a series of experiments was conducted using a milling machine on a CK45 work piece. Tool wear was measured by an optical microscope. To improve the accuracy and reliability of the monitoring system, tool wear state was classified into five groups, namely, no wear, slight wear, normal wear, severe wear and broken tool. Experiments were conducted with the aforementioned tool wear states, and different machining conditions and data were extracted. An increase in current amplitude was observed as the tool wear increased. Furthermore, effects of parameters such as tool wear, feed, and cut depth on motor current consumption were analyzed. Considering the complexity of the wear state classification, a multi-layer neural network was used. The root mean square of motor current, feed, cut depth, and tool rpm were chosen as the input and amount of flank wear as the output of MLP. Results showed good performance of the designed tool wear monitoring system.

  1. Edge loading has a paradoxical effect on wear in metal-on-polyethylene total hip arthroplasties.

    Science.gov (United States)

    Harris, William H

    2012-11-01

    Edge wear is an adverse factor that can negatively impact certain THAs. In some metal-on-metal THAs, it can lead to adverse tissue reactions including aseptic lymphocytic vasculitis-associated lesions and even to pseudotumor formation. In some ceramic-on-ceramic THAs, it can lead to squeaking and/or stripe wear. Edge wear in metal-on-metal and ceramic-on-ceramic THAs can also be associated with accelerated wear across the articulation of these joints. I asked: Does edge wear occur in metal-on-polyethylene (MOP) articulations? And if so, does it increase joint wear? I examined the evidence in the literature for edge wear occurring in MOP THA and then assessed the evidence in the literature for data supporting the concept that edge wear in MOP hips could accelerate wear across the articulation over time. Extensive data in the literature confirm edge wear is common in MOP THA. Surprisingly, the evidence does not support that it accelerates wear across the articulation. In fact, substantial data support the concept that it does not. These observations suggest, in terms of edge wear accelerating overall wear, MOP articulation may have a privileged position compared to hard-on-hard THA articulations.

  2. Coupling behavior between adhesive and abrasive wear mechanism of aero-hydraulic spool valves

    Institute of Scientific and Technical Information of China (English)

    Chen Yunxia; Gong Wenjun; Kang Rui

    2016-01-01

    Leakage due to wear is one of the main failure modes of aero-hydraulic spool valves. This paper established a practical coupling wear model for aero-hydraulic spool valves based on dynamic system modelling theory. Firstly, the experiment for wear mechanism verification proved that adhesive wear and abrasive wear did coexist during the working process of spool valves. Sec-ondly coupling behavior of each wear mechanism was characterized by analyzing actual time-variation of model parameters during wear evolution process. Meanwhile, Archard model and three-body abrasive wear model were utilized for adhesive wear and abrasive wear, respectively. Furthermore, their coupling wear model was established by calculating the actual wear volume. Finally, from the result of formal test, all the required parameters for our model were obtained. The relative error between model prediction and data of pre-test was also presented to verify the accuracy of model, which demonstrated that our model was useful for providing accurate prediction of spool valve’s wear life.

  3. An Influence of Parameters of Micro-Electrical Discharge Machining On Wear of Tool Electrode

    DEFF Research Database (Denmark)

    Puthumana, Govindan

    2017-01-01

    a novel modeling and analysis approachof the tool wear in micro-EDM using a systematic statistical method exemplifying theinfluences of capacitance, feed rate and voltage on the tool wear ratio. The associationbetween tool wear ratio and the input factors is comprehended by using main effectplots......, interaction effects and regression analysis. A maximum variation of four-fold inthe tool wear ratio have been observed which indicated that the tool wear ratio variessignificantly over the trials. As the capacitance increases from 1 to 10 nF, the increasein tool wear ratio is by 33%. An increase in voltage...... as well as capacitance would leadto an increase in the number of charged particles, the number of collisions amongthem, which further enhances the transfer of the proportion of heat energy to the toolsurface. Furthermore, to model the tool wear phenomenon, a regression relationshipbetween tool wear ratio...

  4. Sliding Wear and Friction Behavior of Fuel Rod Material in Water and Dry State

    Science.gov (United States)

    Park, Jin Moo; Kim, Jae Hoon; Jeon, Kyeong Lak; Park, Jun Kyu

    In water cooled reactors, the friction between spacer grid and fuel rod can lead to severe wear and it is an important topic to study. In the present study, sliding wear behavior of zirconium alloy was investigated in water and dry state using the pin-on-disc sliding wear tester. Sliding wear resistance of zirconium alloy against heat treated inconel alloy was examined at room temperature. The parameters in this study were sliding velocity, axial load and sliding distance. The wear characteristics of zirconium alloy was evaluated by friction coefficient, specific wear rate and wear volume. The micro-mechanisms responsible for wear in zirconium alloy were identified to be micro-cutting, micro-pitting, delamination and micro-cracking of deformed surface zone.

  5. Evaluation of Two Total Hip Bearing Materials for Resistance to Wear Using a Hip Simulator

    Directory of Open Access Journals (Sweden)

    Kenneth R. St. John

    2015-06-01

    Full Text Available Electron beam crosslinked ultra high molecular weight polyethylene (UHMWPE 32 mm cups with cobalt alloy femoral heads were compared with gamma-irradiation sterilized 26 mm cups and zirconia ceramic heads in a hip wear simulator. The testing was performed for a total of ten million cycles with frequent stops for cleaning and measurement of mass losses due to wear. The results showed that the ceramic on UHMWPE bearing design exhibited higher early wear than the metal on highly crosslinked samples. Once a steady state wear rate was reached, the wear rates of the two types of hip bearing systems were similar with the ceramic on UHMPWE samples continuing to show a slightly higher rate of wear than the highly crosslinked samples. The wear rates of each of the tested systems appear to be consistent with the expectations for low rates of wear in improved hip replacement systems.

  6. Sensitivity of Dielectric Properties to Wear Process on Carbon Nanofiber/High-Density Polyethylene Composites.

    Science.gov (United States)

    Liu, Tian; Wood, Weston; Zhong, Wei-Hong

    2011-12-01

    We examined the correlation of wear effects with dielectric properties of carbon nanofibers (CNFs; untreated and organosilane-treated)-reinforced high-density polyethylene (HDPE) composites. Wear testing for the nanocomposites over up to 120 h was carried out, and then, dielectric permittivity and dielectric loss factor of the polymer composites with the increased wear time were studied. Scanning electron microscope and optical microscope observations were made to analyze the microstructure features of the nanocomposites. The results reveal that there exist approximate linear relationships of permittivity with wear coefficient for the nanocomposites. Composites containing silanized CNFs with the sufficiently thick coating exhibited high wear resistance. The change in permittivity was more sensitive to the increased wear coefficient for the nanocomposites with lower wear resistance. This work provides potential for further research on the application of dielectric signals to detect the effects of wear process on lifetime of polymeric materials.

  7. Sensitivity of Dielectric Properties to Wear Process on Carbon Nanofiber/High-Density Polyethylene Composites

    Directory of Open Access Journals (Sweden)

    Liu Tian

    2011-01-01

    Full Text Available Abstract We examined the correlation of wear effects with dielectric properties of carbon nanofibers (CNFs; untreated and organosilane-treated-reinforced high-density polyethylene (HDPE composites. Wear testing for the nanocomposites over up to 120 h was carried out, and then, dielectric permittivity and dielectric loss factor of the polymer composites with the increased wear time were studied. Scanning electron microscope and optical microscope observations were made to analyze the microstructure features of the nanocomposites. The results reveal that there exist approximate linear relationships of permittivity with wear coefficient for the nanocomposites. Composites containing silanized CNFs with the sufficiently thick coating exhibited high wear resistance. The change in permittivity was more sensitive to the increased wear coefficient for the nanocomposites with lower wear resistance. This work provides potential for further research on the application of dielectric signals to detect the effects of wear process on lifetime of polymeric materials.

  8. A Case of Atypical Mucin Balls Wearing Extended Wear of Silicone Hydrogel Lens for Therapeutic Use

    Directory of Open Access Journals (Sweden)

    Yusuke Matsuzaki

    2013-01-01

    Full Text Available A 25-year-old man visited our hospital showing atopic conjunctivitis and corneal shield ulcer on his left eye. Although eye drops of 0.1% of betamethasone sodium phosphate and 0.1% of hyaluronic acid ophthalmic solution were prescribed, calcific corneal opacities developed. The corrected visual acuity decreased to 6/20 in Snellen chart. After corneal epithelial exfoliation, removal of calcific corneal opacity was scrubbed with MQA soaked in 0.05 M of ethylenediaminetetraacetic acid (EDTA. After washing the eye with 200 mL of physiological saline, a silicon hydrogel lens, PureVision (balafilcon A, was inserted to obtain pain relief for the therapeutic use. At postoperative day 11, mucin balls were found between cornea and contact lens and stained by rose bengal dye. One of them was atypically larger than usual, and the major axis was approximately 1.5 mm. Wearing lens was stopped, and all of mucin balls and corneal staining were disappeared at postoperative day. Little corneal opacity remained, and visual acuity after surgery recovered to 14/20 at five months.

  9. Changing life jacket wearing behavior: an evaluation of two approaches.

    Science.gov (United States)

    Mangione, Thomas; Chow, Wendy

    2014-05-01

    In the United States during 1999-2012, about 4 per cent of adults wore life jackets while engaged in recreation on powerboats. Educational campaigns have promoted life jacket use. Mandatory use regulations target primarily children or boaters on personal watercrafts or water skiing. We describe findings from two interventions - 'Wear It California!', a targeted marketing campaign in the California Delta region and mandatory wear regulations at four US Army Corps of Engineers (USACE) lakes in the state of Mississippi. Before the campaign in the Delta, adult wear was 8.5 per cent, increasing to 12.1 per cent during the first year, dipping to 9.4 per cent during the second year, and rising slightly to 10.5 per cent 3 plus years after the campaign. Before mandatory regulations at USACE lakes, adult wear was 13.7 per cent, increasing to 75.6 per cent during the first year, 70.1 per cent during the second year, and remaining high at 68.1 per cent in the third year. Policymakers should consider these findings when choosing how to increase life jacket use.

  10. Corrosion-Wear Process Under Rolling-Sliding Motion.

    Science.gov (United States)

    1987-08-01

    above analysis forwarded by Rabinowicz is of a fundamental nature, such analysis and the available literature provide very little insight and solution... Rabinowicz , Friction and Wear of Materials, John Wiley and Sons, New York, 1965, p. 186. * 27. K. Y. Kim and S. Bhattacharyya, Quarterly Progress Report

  11. Characterization of Ion Implanted and Laser Processed Wear Surfaces.

    Science.gov (United States)

    1986-04-22

    reactivity of the 8. E. Rabinowicz , "Friction and Wear of materials is very great, as was the case Materials", 75, John Wiley and Sons on the first...pass on the TiC/Ti disk fol- Inc., N. Y. (1966). lowing implantation . Severe stickslip, leading to high frictional losses, however, 9. Rabinowicz , E

  12. Combined Corrosion and Wear of Aluminium Alloy 7075-T6

    NARCIS (Netherlands)

    Liu, Y.; Mol, J.M.C.; Janssen, G.C.A.M.

    2016-01-01

    The aluminium alloy 7075-T6 is widely used in engineering. In some applications, like slurry transport, corrosion and abrasion occur simultaneously, resulting in early material failure. In the present work, we investigated the combined effect of corrosion and wear on the aluminium alloy 7075-T6. We

  13. Wear prediction on total ankle replacement effect of design parameters

    CERN Document Server

    Saad, Amir Putra Bin Md; Harun, Muhamad Noor; Kadir, Mohammed Rafiq Abdul

    2016-01-01

    This book develops and analyses computational wear simulations of the total ankle replacement for the stance phase of gait cycle. The emphasis is put on the relevant design parameters. The book presents a model consisting of three components; tibial, bearing and talar representing their physiological functions.

  14. Determination of Muzzle Velocity Loss by Bore Wear Pattern

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-xin; WANG Gui-yu

    2007-01-01

    A method to determine muzzle velocity loss according to the actual measured bore wear pattern is proposed.Therefore, it is unnecessary to conduct live firing and other experiments for determination of muzzle velocity loss. It has been applied to a national military standard since July 1, 2004.

  15. Wear of nanofilled dental composites at varying filler concentrations.

    Science.gov (United States)

    Lawson, Nathaniel C; Burgess, John O

    2015-02-01

    The aim of this study is to examine the effects of nanofiller concentration on the mechanisms of wear of a dental composite. Nanofilled composites were fabricated with a bisphenol A glycidyl methacrylate polymer and 40 nm SiO2 filler particles at three filler loads (25, 50, and 65 wt %). The elastic modulus, flexural strength, and hardness of the composites and the unfilled resin were measured. The materials (n = 8) were tested in the modified wear testing device at 50,000, 100,000, and 200,000 cycles with 20N force at 1 Hz. A 33% glycerine lubricant and stainless steel antagonist were used. The worn composite and antagonist surfaces were analyzed with noncontact profilometry and SEM. The volumetric wear data indicated that there are significant differences between filler concentrations and cycles (p composites. Increasing filler content increased hardness and modulus and increased flexural strength up to 50% fill. SEM evaluation of the worn specimens indicated that the resin and 25% filled materials exhibited cracking and failed by fatigue and the 50 and 65% filled materials exhibited microcutting and failed by abrasive wear. Based on the results of this study, composite manufacturers are recommended to use a filler concentration between 25 and 50% when using nanosized filler particles. © 2014 Wiley Periodicals, Inc.

  16. Corrosion wear fracture of new {beta} biomedical titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Niinomi, M.; Fukunaga, K.-I. [Toyohashi Univ. of Technol. (Japan). Dept. of Production Syst. Eng.; Kuroda, D.; Morinaga, M.; Kato, Y.; Yashiro, T.; Suzuki, A.

    1999-05-15

    Metallic materials such as stainless steel, Co-Cr alloy, pure titanium and titanium alloys have been used for surgical implant materials. The {alpha} + {beta} type titanium alloy such as Ti-6Al-4V ELI has been most widely used as an implant material for artificial hip joint and dental implant because of its high strength and excellent corrosion resistance. Toxicity of alloying elements in conventional biomedical titanium alloys like Al and V, and the high modulus of elasticity of these alloy as compared to that of bone have been, however, pointed out [1,2]. New {beta} type titanium alloys composed of non-toxic elements like Nb, Ta, Zr, Mo and Sn with lower moduli of elasticity, greater strength and greater corrosion resistance were, therefore, designed in this study. The friction wear properties of titanium alloys are, however, low as compared to those of other conventional metallic implant materials such as stainless steels and Co-Cr alloy. Tensile tests and friction wear tests in Ringer`s solution were conducted in order to investigate the mechanical properties of designed alloys. The friction wear characteristics of designed alloys and typical conventional biomedical titanium alloys were evaluated using a pin-on-disk type friction wear testing system and measuring the weight loss and width of groove of the specimen. (orig.) 8 refs.

  17. Wear Tests of a Potential Biolubricant for Orthopedic Biopolymers

    Directory of Open Access Journals (Sweden)

    Martin Thompson

    2015-03-01

    Full Text Available Most wear testing of orthopedic implant materials is undertaken with dilute bovine serum used as the lubricant. However, dilute bovine serum is different to the synovial fluid in which natural and artificial joints must operate. As part of a search for a lubricant which more closely resembles synovial fluid, a lubricant based on a mixture of sodium alginate and gellan gum, and which aimed to match the rheology of synovial fluid, was produced. It was employed in a wear test of ultra high molecular weight polyethylene pins rubbing against a metallic counterface. The test rig applied multidirectional motion to the test pins and had previously been shown to reproduce clinically relevant wear factors for ultra high molecular weight polyethylene. After 2.4 million cycles (125 km of sliding in the presence of the new lubricant, a mean wear factor of 0.099 × 10−6 mm3/Nm was measured for the ultra high molecular weight polyethylene pins. This was over an order of magnitude less than when bovine serum was used as a lubricant. In addition, there was evidence of a transfer film on the test plates. Such transfer films are not seen clinically. The search for a lubricant more closely matching synovial fluid continues.

  18. In situ complement activation by polyethylene wear debris.

    NARCIS (Netherlands)

    DeHeer, D.H.; Engels, J.A.; Vries, A.S. de; Knapp, R.H.; Beebe, J.D.

    2001-01-01

    A frequent long-term complication of total joint arthroplasty is aseptic loosening, the end result of wear debris accumulation, synovitis, and osteolysis about the implant-bone or cement-bone interface. Complement, an effector system in plasma, synovial fluid, and tissue, has powerful chemotactic, i

  19. Concept to comfort-condition subjects wearing restrictive clothing

    Science.gov (United States)

    Tucker, E. M.

    1968-01-01

    Heat exchanger maintains a desirable thermal balance in a subject wearing restrictive clothing. A grid of high thermal conductance fibers, in contact with the skin, transfers heat to or from the skin surface by means of a system of ducts, carrying the transfer fluid which is maintained at a controlled temperature.

  20. Synergetic approachto simulation of physical wear of engineering technical systems

    Directory of Open Access Journals (Sweden)

    Kirillov Andrey Mikhaylovich

    2015-05-01

    Full Text Available In course of time in structural elements of engineering technical systems defects and damages are accumulated, which is caused by loadings and environmental influence. The defects are any inconsistencies with normative documents, and damages are discontinuances of structure. The defects and damages lead to decrease of operational properties of structures (their bearing capacity, waterproofing, thermal resistance, etc. The occurrences of such character are called physical wear.In the article the authors show the possibility of phase trajectory use of the processes of physical wear, creep and cusp catastrophe for determinating the critical timepoint, corresponding to the beginning of the system damage catastrophic growth. The alternative approach to the description of the processes of physical wear and creep of pavement consisting in comparison of asphalt concrete creep curve and the curve of the mathematical model of cusp catastrophe, is received. The applied synergetic approach gives us the chance to improve the existing and create new methods of pavement resource forecasting and assessment of physical wear of any technical constructions.

  1. On the Durability and Wear Resistance of Transparent Superhydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Ilker S. Bayer

    2017-01-01

    Full Text Available Transparent liquid repellent coatings with exceptional wear and abrasion resistance are very demanding to fabricate. The most important reason for this is the fact that majority of the transparent liquid repellent coatings have so far been fabricated by nanoparticle assembly on surfaces in the form of films. These films or coatings demonstrate relatively poor substrate adhesion and rubbing induced wear resistance compared to polymer-based transparent hydrophobic coatings. However, recent advances reported in the literature indicate that considerable progress has now been made towards formulating and applying transparent, hydrophobic and even oleophobic coatings onto various substrates which can withstand certain degree of mechanical abrasion. This is considered to be very promising for anti-graffiti coatings or treatments since they require resistance to wear abrasion. Therefore, this review intends to highlight the state-of-the-art on materials and techniques that are used to fabricate wear resistant liquid repellent transparent coatings so that researchers can assess various aptitudes and limitations related to translating some of these technologies to large scale stain repellent outdoor applications.

  2. Tooth wear : a systematic review of treatment options

    NARCIS (Netherlands)

    Muts, Erik-Jan; van Pelt, Hans; Edelhoff, Daniel; Krejci, Ivo; Cune, Marco

    2014-01-01

    STATEMENT OF PROBLEM: Treatment of tooth wear is increasing. Because no evidence-based guidelines are available, the clinician may have difficulties deciding which treatment option to choose to resolve complex situations. PURPOSE: The purpose of this systematic review was to identify similarities am

  3. Screening of stabilized crosslinked polyethylene using a novel wear tester.

    Science.gov (United States)

    Hoffmann, M; Gonzalez-Mora, V; Chiesa, R; Cigada, A; Stroosnijder, M F

    2002-01-01

    A novel pin-on-disk type wear tester is described allowing a rapid screening of different types of polyethylene under both unidirectional and multidirectional sliding motion. The wear of four polyethylene materials sliding against a roughened CoCrMo alloy was evaluated: a non-irradiated UHMWPE, a UHMWPE irradiated with a dose of 25 kGy in air, and two types of crosslinked UHMWPE (100 kGy, air), which were subjected to a stabilization heat treatment in nitrogen at 155 degrees C for 72 hours (XLPE I) and in water at 130 degrees C for 72 hours (XLPE II), respectively.Under multidirectional sliding conditions both types of XLPE exhibited significantly less wear with respect to the 25 kGy irradiated UHMWPE and the non-irradiated UHMWPE, even under the rough counterface conditions applied. Under unidirectional sliding motion both types of XLPE exhibited the highest wear of all materials tested, because the orientation hardening effect acting under linear lubricated condition is less pronounced for crosslinked polyethylene.

  4. Porosity and wear resistance of flame sprayed tungsten carbide coatings

    Science.gov (United States)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermal-sprayed coatings offer practical and economical solutions for corrosion and wear protection of components or tools. To improve the coating properties, heat treatment such as preheat is applied. The selection of coating and substrate materials is a key factor in improving the quality of the coating morphology after the heat treatment. This paper presents the experimental results regarding the effect of preheat temperatures, i.e. 200°C, 300°C and 400°C, on porosity and wear resistance of tungsten carbide (WC) coating sprayed by flame thermal coating. The powders and coatings morphology were analyzed by a Field Emission Scanning Electron Microscope equipped with Energy Dispersive Spectrometry (FE-SEM/EDS), whereas the phase identification was performed by X-Ray diffraction technique (XRD). In order to evaluate the quality of the flame spray obtained coatings, the porosity, micro-hardness and wear rate of the specimens was determined. The results showed that WC coating gives a higher surface hardness from 1391 HVN up to 1541 HVN compared to that of the non-coating. Moreover, the wear rate increased from 0.072 mm3/min. to 0.082 mm3/min. when preheat temperature was increased. Preheat on H13 steel substrate can reduce the percentage of porosity level from 10.24 % to 3.94% on the thermal spray coatings.

  5. Reappraisal of Color Change in Women's Wears in China

    Institute of Scientific and Technical Information of China (English)

    CONG Shan; ZHOU Xu-dong

    2002-01-01

    This paper attempts to quantify color attribute change in women's wear products in China by the computer-aided color design system. A method of classification and analysis of fashion color is proposed. In addition, data from several popular ragazines are classified and tested for evidence of evolving activity of fashion color.

  6. Gears castings from ductile iron of improved abrasion wear resistance

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2011-10-01

    Full Text Available The aim of this study was to develop an industrial technological process for the manufacturing of castings from alloyed ductile iron characterized by improved resistance to abrasion wear. The outcome of the study was the implementation of developed technology under the industrial conditions of ASPAMET Foundry Plant and start up of production of a wide range of cast gears.

  7. Effect of wearing a mouthguard on the vestibulocollic reflex.

    Science.gov (United States)

    Mizumachi, Makoto; Sumita, Yosuke; Ueno, Toshiaki

    2008-04-01

    It has been speculated that the use of a mouthguard improves athletic ability such as muscular strength and equilibrium. The postural system is equipped with response patterns that correct for unexpected perturbations. These responses are driven by immediate feedback from visual, vestibular, and somatosensory information. These are integrated by the central nervous system. We analysed the possibility that wearing a mouthguard influences vestibular information via the vestibulocollic reflex (VCR) in the sagittal plane. The input of the VCR is vestibular afferent activity and its output is neck muscle activation. With the subject in the supine position, the apparatus used in this study induces the VCR by subjecting the head to abrupt vertical acceleration by sudden free fall under the head's own weight. Surface electromyographic (EMG) recordings in the sternocleidomastoid muscles (SCM) of 14 participants were analysed. There were no significant differences in the amplitude of the VCR within the left and right SCM whether subjects were or were not wearing a mouthguard (P=0.3227 within left SCM; P=0.9686 within right SCM). These results suggest that wearing a mouthguard has no effect on the VCR in the sagittal plane when supine, and so that vestibular sensory information is unaffected by wearing a mouthguard, in this context. Further research is required to examine whether this also holds true in more functional, upright and dynamic body positions.

  8. Development of wear resistant ceramic coatings for diesel engine components

    Energy Technology Data Exchange (ETDEWEB)

    Haselkorn, M.H. (Caterpillar, Inc., Peoria, IL (United States))

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  9. GMT azimuth bogie wheel-rail interface wear study

    Science.gov (United States)

    Teran, Jose; Lindh, Cory; Morgan, Chris; Manuel, Eric; Bigelow, Bruce C.; Burgett, William S.

    2016-07-01

    Performance of the GMT azimuth drive system is vital for the operation of the telescope and, as such, all components subject to wear at the drive interface merit a high level of scrutiny for achieving a proper balance between capital costs, maintenance costs, and the risk for downtime during planned and unplanned maintenance or replacement procedures. Of particular importance is the interface between the azimuth wheels and rail, as usage frequency is high, the full weight of the enclosure must be transferred through small patches of contact, and replacement of the rail would pose a greater logistical challenge than the replacement of smaller components such as bearings and gearmotors. This study investigates tradeoffs between various wheel-rail and roller-track interfaces, including performance, complexity, and anticipated wear considerations. First, a survey of railway and overhead crane industry literature is performed and general detailing recommendations are made to minimize wear and the risk of rolling contact fatigue. Second, Adams/VI-Rail is used to simulate lifetime wear of four specific configurations under consideration for the GMT azimuth wheel-rail interface; all studied configurations are shown to be viable, and their relative merits are discussed.

  10. RPP-WPT Slurry Wear Evaluation: Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.R.

    2001-06-12

    Tests are planned to measure the wear rates in scaled flow loops that represent full-scale systems in Pretreatment sections of the Waste Treatment Plant to be built as part of the Department of Energy (DOE) River Protection Project. Those tests are to be done in the Experimental Thermal Fluids Laboratory of the Savannah River Technology Center at the DOE Savannah River Site.

  11. Combined Corrosion and Wear of Aluminium Alloy 7075-T6

    NARCIS (Netherlands)

    Liu, Y.; Mol, J.M.C.; Janssen, G.C.A.M.

    2016-01-01

    The aluminium alloy 7075-T6 is widely used in engineering. In some applications, like slurry transport, corrosion and abrasion occur simultaneously, resulting in early material failure. In the present work, we investigated the combined effect of corrosion and wear on the aluminium alloy 7075-T6. We

  12. Wear of double crown systems: electroplated vs. casted female part

    Directory of Open Access Journals (Sweden)

    Stefan Bayer

    2012-06-01

    Full Text Available OBJECTIVES: The wear of telescopic crowns is a common problem often reducing the patient's satisfaction with the denture and resulting in a renewal of the denture. The study aims to compare the wear behavior of conical crowns using electroplated copings (group E with standard telescopic crowns with cast female parts (group C. MATERIAL AND METHODS: 10 conical crowns were milled for each group of a cast gold alloy. The specimen of group E had a conicity of 2º. The cast secondary crowns of group C had a 0º design. The electroplated coping was established by direct electroforming. An apparatus accomplishing 10,000 wear cycles performed the wear test. The retentive forces and the correlating distance during insertion and separation were measured. The wear test was separated in a start phase, an initial wear phase and the long term wear period. The retention force value and the force-distance integral of the first 0.33 mm of each cycle were calculated. RESULTS: The retentive forces were significantly higher for group E and the integrals were significantly lower for this group except the integral at cycle 10,000. The changes of retention force and integral did not differ significantly between both groups in all phases. The change of the integrals as well as the integral at the particular cycles showed higher interquartile distances for group C. CONCLUSIONS: Within the limitations of this study the tested conical crowns showed clinically acceptable retentive properties. The values reached a range comparable to retentive elements tested in recent literature. The values of group C showed higher ranges. The force measured for group E was significantly higher than for group C but the integrals showed an opposite tendency. The results indicate that an exclusive analysis of the force is not sufficient as the integral is not equivalent to the force although it describes the retentive property of the system in a better way than the force over a distance is

  13. Mechanisms for fatigue and wear of polysilicon structural thinfilms

    Energy Technology Data Exchange (ETDEWEB)

    Alsem, Daniel Henricus [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    Fatigue and wear in micron-scale polysilicon structural films can severely impact the reliability of microelectromechanical systems (MEMS). Despite studies on fatigue and wear behavior of these films, there is still an on-going debate regarding the precise physical mechanisms for these two important failure modes. Although macro-scale silicon does not fatigue, this phenomenon is observed in micron-scale silicon. It is shown that for polysilicon devices fabricated in the MUMPs foundry and SUMMiT process stress-lifetime data exhibits similar trends in ambient air, shorter lifetimes in higher relative humidity environments and no fatigue failure at all in high vacuum. Transmission electron microscopy of the surface oxides of the samples show an approximate four-fold thickening of the oxide at stress concentrations after fatigue failure, but no thickening after fracture in air or after fatigue cycling in vacuo. It is found that such oxide thickening and fatigue failure (in air) occurs in devices with initial oxide thicknesses of ~4-20 nm. Such results are interpreted and explained by a reaction layer fatigue mechanism; specifically, moisture-assisted subcritical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure. Polysilicon specimens from the SUMMiT process are used to study wear mechanisms in micron-scale silicon in ambient air. Worn parts are examined by analytical scanning and transmission electron microscopy, while temperature changes are monitored using infrared microscopy. These results are compared with the development of values of static coefficients of friction (COF) with number of wear cycles. Observations show amorphous debris particles (~50-100 nm) created by fracture through the silicon grains (~500 nm), which subsequently oxidize, agglomerate into clusters and create plowing tracks. A nano-crystalline layer (~20-200 nm) forms at worn regions. No dislocations or

  14. Surface and sliding wear behaviour of different coatings and steels

    Energy Technology Data Exchange (ETDEWEB)

    Vera-Cardenas, E.E. [Universidad Politecnica de Pachuca, Zempoala, Hidalgo (Mexico)]. E-mail: evera@upp.edu.mx; Vite-Torres, M. [Instituto Politecnico Nacional, Mexico D.F. (Mexico)]. E-mail: drmanulvite9@hotmail.com; Lewis, R. [University of Sheffield (United Kingdom)]. E-mail: roger.lewis@sheffield.ac.uk

    2012-01-15

    In this work, the sliding wear behaviour of the coatings TiN, CrN and WC/C applied on steel substrates was studied using a reciprocating wear test machine. All tests were carried out in dry conditions, at room temperature (20-23 degrees Celsius and 45% - 50% relative humidity). The average sliding velocity was 0.08 m/s and an amplitude of 2 mm was used. The applied loads were 11.76 N (Po = 1.74 GPa) and 7.84 N (Po = 1.52 GPa). Optical microscopy was used to observe the characteristics of wear scars and spalls and possible causes of their formation. The variation of the friction coefficient against the number of cycles was obtained. This was used to determine more precisely the time (number of cycles) where the coating presented the first signs of wear, in addition Energy Dispersive X-ray analysis (EDS) was performed, as well as Scanning Electron Microscopy (SEM) and hardness tests on the wear traces, which reinforced the previous observations. Thus it was possible to know the wear life of different coatings and possible causes of variation. Increasing the load was an important factor in the variation of wear life results. But it is also important to consider other factors such as surface roughness and thickness of coatings. [Spanish] En este trabajo se estudio el comportamiento en desgaste por deslizamiento de los recubrimientos de TiN, CrN y WC/C aplicados sobre sustratos de acero. Las pruebas se realizaron con una maquina reciprocante en condiciones secas a temperatura ambiente (20-23 grados centigrados y 45% - 50% de humedad relativa). Se empleo una velocidad promedio de 0.08 m/s y una amplitud de 2 mm. Las cargas aplicadas fueron de 11.76N (Po = 1.74 GPa) y de 7.84 N (Po = 1.52 GPa). Se realizo microscopia optica para observar las caracteristicas de las zonas de desgaste y sus posibles causas de formacion. Se obtuvo graficamente la variacion del coeficiente de friccion con el numero de ciclos. Estos datos se emplearon para determinar con mayor precision el

  15. Problems of locomotive wheel wear in fleet replacement

    Directory of Open Access Journals (Sweden)

    L.P. Lingaytis

    2013-08-01

    Full Text Available Purpose. To conduct a research and find out the causes of defects appearing on the wheel thread of freight locomotives 2М62 and SIEMENS ER20CF. Methodology. To find the ways to solve this problem comparing the locomotive designs and their operating conditions. Findings. After examining the nature of the wheel wear the main difference was found: in locomotives of the 2M62 line wears the wheel flange, and in the locomotives SIEMENS ER20CF – the tread surface. After installation on the 2M62 locomotive the lubrication system of flanges their wear rate significantly decreased. On the new freight locomotives SIEMENS ER20CF the flange lubrication systems of the wheel set have been already installed at the factory, however the wheel thread is wearing. As for locomotives 2M62, and on locomotives SIEMENS ER20CF most wear profile skating wheels of the first wheel set. On both locomotive lines the 2М62 and the SIEMENS ER20CF the tread profile of the first wheel set most of all is subject to the wear. After reaching the 170 000 km run, the tread surface of some wheels begins to crumble. There was a suspicion that the reason for crumb formation of the wheel surface may be insufficient or excessive wheel hardness or its chemical composition. In order to confirm or deny this suspicion the following studies were conducted: the examination of the rim surface, the study of the wheel metal hardness and the document analysis of the wheel production and their comparison with the results of wheel hardness measurement. Practical value. The technical condition of locomotives is one of the bases of safety and reliability of the rolling stock. The reduction of the wheel wear significantly reduces the operating costs of railway transport. After study completion it was found that there was no evidence to suggest that the ratio of the wheel-rail hardness could be the cause of the wheel surface crumbling.

  16. Resistance of weldclads made by flux-cored arc welding technology against erosive wear

    Directory of Open Access Journals (Sweden)

    I. Pernis

    2013-07-01

    Full Text Available The paper deals with the tribological properties of investigated types of hardfacing materials at erosive wear process. Influence of impact angle of abrasive grains on wear resistance and microhardness changes of hardfacing layer were investigated too. From quantitative aspect weldclads wear resistance were evaluated on the base of weight loss. Results achieved showed that impact angle is one of determining factors of material’s wear measure.

  17. Solid Bonded Films or Monolithic Ceramics in Tracked Chains of Construction Equipments for Wear Management

    Science.gov (United States)

    2004-06-01

    and the sprocket, in which abrasive wear is predominant. According to Rabinowicz [17], the abrasive wear is shared into three regions of low wear/high...12 RTO-MP-AVT-109 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED The methodology of Rabinowicz is more valid for metals and represents a...494-499 [17] E. Rabinowicz Abrasive wear resistance as a material test, Lubrication Engineering 33 (1977), p. 378 [18] Uetz, H. (ed

  18. A Novel Method for Assessment of Polyethylene Liner Wear in Radiopaque Tantalum Acetabular Cups

    DEFF Research Database (Denmark)

    Troelsen, Anders; Greene, Meridith E; Ayers, David C

    2015-01-01

    Conventional radiostereometric analysis (RSA) for wear is not possible in patients with tantalum cups. We propose a novel method for wear analysis in tantalum cups. Wear was assessed by gold standard RSA and the novel method in total hip arthroplasty patients enrolled in a randomized controlled...... to the gold standard in titanium cups. The novel method offered accurate assessment and is a viable solution for assessment of wear in studies with tantalum cups....

  19. Prevalence and severity of incisal and occlusal tooth wear in an adult Swedish population.

    Science.gov (United States)

    Hugoson, A; Bergendal, T; Ekfeldt, A; Helkimo, M

    1988-10-01

    The material consisted of 585 randomly selected dentate individuals from the community of Jönköping, Sweden, who in 1983 reached the age of 20, 30, 40, 50, 60, 70, or 80 years. The degree of incisal or occlusal wear was evaluated for each single tooth in accordance with the following criteria: 0 = no wear or negligible wear of enamel; 1 = obvious wear of enamel or wear through the enamel to dentin in single spots; 2 = wear of dentin up to one-third of the crown height; 3 = wear of dentin more than one-third of the crown height and/or excessive wear of tooth restorative material. Among the 20-year-olds 35% of the subjects had no or slight incisal or occlusal wear. The corresponding figures for the 30- to 80-year age groups were 20%, 32%, 18%, 14%, 26%, and 23%, respectively. For the age groups 20-80 years, the percentage of teeth with incisal or occlusal wear in accordance with criteria 1-3 was 13%, 20%, 16%, 24%, 23%, 23%, and 23%, respectively. Men presented more teeth with wear than women, the difference being significant for all age groups except the 20- and 60-year-olds. Among the 20-year-olds 6% had one or more teeth with wear scored 2. Among subjects aged 30 and 70 years 10% and 31%, respectively, showed tooth wear with score 2. Wear with score 3 was only found in 2% of the total population. There was an increase in the number of teeth with incisal or occlusal wear with age. With increasing age, there was also a change in distribution of wear within the dentition.

  20. Communication research between working capacity of hard- alloy cutting tools and fractal dimension of their wear

    Science.gov (United States)

    Arefiev, K.; Nesterenko, V.; Daneykina, N.

    2016-06-01

    The results of communication research between the wear resistance of the K applicability hard-alloy cutting tools and the fractal dimension of the wear surface, which is formed on a back side of the cutting edge when processing the materials showing high adhesive activity are presented in the paper. It has been established that the wear resistance of tested cutting tools samples increases according to a fractal dimension increase of their wear surface.

  1. Development of wear-resistant coatings for cobalt-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cockeram, B.V.

    1999-10-22

    The level of nuclear plant radiation exposure due to activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear resistant coating. Laboratory pin-on-disc and rolling contact wear tests were used to evaluate the wear performance of several coatings. Based on the results of these tests, multilayer Cr-nitride coatings and ion nitriding are the most promising approaches.

  2. Advanced Wear-resistant Nanocomposites for Increased Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Cook, B. A.; Harringa, J. L.; Russel, A. M.

    2012-12-01

    This report summarizes the work performed by an Ames-led project team under a 4-year DOE-ITP sponsored project titled, 'Advanced Wear-resistant Nanocomposites for Increased Energy Efficiency.' The Report serves as the project deliverable for the CPS agreement number 15015. The purpose of this project was to develop and commercialize a family of lightweight, bulk composite materials that are highly resistant to degradation by erosive and abrasive wear. These materials, based on AlMgB{sub 14}, are projected to save over 30 TBtu of energy per year when fully implemented in industrial applications, with the associated environmental benefits of eliminating the burning of 1.5 M tons/yr of coal and averting the release of 4.2 M tons/yr of CO{sub 2} into the air. This program targeted applications in the mining, drilling, machining, and dry erosion applications as key platforms for initial commercialization, which includes some of the most severe wear conditions in industry. Production-scale manufacturing of this technology has begun through a start-up company, NewTech Ceramics (NTC). This project included providing technical support to NTC in order to facilitate cost-effective mass production of the wear-resistant boride components. Resolution of issues related to processing scale-up, reduction in energy intensity during processing, and improving the quality and performance of the composites, without adding to the cost of processing were among the primary technical focus areas of this program. Compositional refinements were also investigated in order to achieve the maximum wear resistance. In addition, synthesis of large-scale, single-phase AlMgB{sub 14} powder was conducted for use as PVD sputtering targets for nanocoating applications.

  3. Surface chemical modification for exceptional wear life of MEMS materials

    Directory of Open Access Journals (Sweden)

    R. Arvind Singh

    2011-12-01

    Full Text Available Micro-Electro-Mechanical-Systems (MEMS are built at micro/nano-scales. At these scales, the interfacial forces are extremely strong. These forces adversely affect the smooth operation and cause wear resulting in the drastic reduction in wear life (useful operating lifetime of actuator-based devices. In this paper, we present a surface chemical modification method that reduces friction and significantly extends the wear life of the two most popular MEMS structural materials namely, silicon and SU-8 polymer. The method includes surface chemical treatment using ethanolamine-sodium phosphate buffer, followed by coating of perfluoropolyether (PFPE nanolubricant on (i silicon coated with SU-8 thin films (500 nm and (ii MEMS process treated SU-8 thick films (50 μm. After the surface chemical modification, it was observed that the steady-state coefficient of friction of the materials reduced by 4 to 5 times and simultaneously their wear durability increased by more than three orders of magnitude (> 1000 times. The significant reduction in the friction coefficients is due to the lubrication effect of PFPE nanolubricant, while the exceptional increase in their wear life is attributed to the bonding between the -OH functional group of ethanolamine treated SU-8 thin/thick films and the -OH functional group of PFPE. The surface chemical modification method acts as a common route to enhance the performance of both silicon and SU-8 polymer. It is time-effective (process time ≤ 11 min, cost-effective and can be readily integrated into MEMS fabrication/assembly processes. It can also work for any kind of structural material from which the miniaturized devices are/can be made.

  4. Optimization of pulsed DC PACVD parameters: Toward reducing wear rate of the DLC films

    Science.gov (United States)

    Ebrahimi, Mansoureh; Mahboubi, Farzad; Naimi-Jamal, M. Reza

    2016-12-01

    The effect of pulsed direct current (DC) plasma-assisted chemical vapor deposition (PACVD) parameters such as temperature, duty cycle, hydrogen flow, and argon/CH4 flow ratio on the wear behavior and wear durability of the diamond-like carbon (DLC) films was studied by using response surface methodology (RSM). DLC films were deposited on nitrocarburized AISI 4140 steel. Wear rate and wear durability of the DLC films were examined with the pin-on-disk method. Field emission scanning electron microscopy, Raman spectroscopy, and nanoindentation techniques were used for studying wear mechanisms, chemical structure, and hardness of the DLC films. RSM results show that duty cycle is one of the important parameters that affect the wear rate of the DLC samples. The wear rate of the samples deposited with a duty cycle of >75% decreases with an increase in the argon/CH4 ratio. In contrast, for a duty cycle of <65%, the wear rate increases with an increase in the argon/CH4 ratio. The wear durability of the DLC samples increases with an increase in the duty cycle, hydrogen flow, and argon/CH4 flow ratio at the deposition temperature between 85 °C and 110 °C. Oxidation, fatigue, abrasive wear, and graphitization are the wear mechanisms observed on the wear scar of the DLC samples deposited with the optimum deposition conditions.

  5. Reduction of Erosion Wear of Mean Pressure Cylinder of Steam Turbines Operating Beyond Critical Parameters

    Directory of Open Access Journals (Sweden)

    V. P. Kascheev

    2009-01-01

    Full Text Available The paper considers problems leading to erosion wear of flowing part of a mean pressure turbine cylinder operating beyond critical parameters. Explanation of erosion wear of flowing part of a mean pressure turbine cylinder which is proved in practice and recommendations for wear reduction are given in the paper

  6. Assessment of the amount of tooth wear on dental casts and intra-oral photographs

    NARCIS (Netherlands)

    Wetselaar, P.; Wetselaar-Glas, M.J.M.; Koutris, M.; Visscher, C.M.; Lobbezoo, F.

    2016-01-01

    Tooth wear is a multifactorial condition, leading to the loss of dental hard tissues. Many grading scales are available to assess the amount of tooth wear, one of which is the tooth wear evaluation system (TWES). A grading scale can be used chairside, on casts and on photographs. The aim was to test

  7. Investigation on the Tribological Behavior and Wear Mechanism of Five Different Veneering Porcelains.

    Directory of Open Access Journals (Sweden)

    Jie Min

    Full Text Available The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains.Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester. Wear tests were performed on a ball-on-flat PLINT fretting wear machine, with lubrication of artificial saliva at 37°C. The friction coefficients were recorded by the testing system. The microstructure features, wear volume, and damage morphologies were recorded and analyzed with a confocal laser scanning microscope and a scanning electron microscope. The wear mechanism was then elucidated.The friction coefficients of the five veneering porcelains differ significantly. No significant correlation between hardness and wear volume was found for these veneering porcelains. Under lubrication of artificial saliva, the porcelain with higher leucite crystal content exhibited greater wear resistance. Additionally, leucite crystal size and distribution in glass matrix influenced wear behavior. The wear mechanisms for these porcelains were similar: abrasive wear dominates the early stage, whereas delamination was the main damage mode at the later stage. Furthermore, delamination was more prominent for porcelains with larger crystal sizes.Wear compatibility between porcelain and natural teeth is important for dental restorative materials. Investigation on crystal content, size, and distribution in glass matrix can provide insight for the selection of dental porcelains in clinical settings.

  8. Tribological behavior and wear mechanism of resin-matrix contact strip against copper with electrical current

    Institute of Scientific and Technical Information of China (English)

    TU Chuan-jun; CHEN Zhen-hua; CHEN Ding; YAN Hong-ge; HE Feng-yi

    2008-01-01

    The resin-matrix pantograph contact strip (RMPCS), which has excellent abrasion resistance with electrical current and friction-reducing function, was developed in view of the traditional contact strips with high maintenance cost, high wear rate with electrical current and severe damage to the copper conducting wire. The characteristics of worn surfaces, cross-section and typical elemental distributions of RMPCS were studied by scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS).The wear behavior and arc discharge of RMPCS against copper were investigated with self-made electrical wear tester. The results show that the electrical current plays a critical role in determining the wear behavior, and the wear rate of the RMPCS against copper with electrical current is 2.7-5.8 times higher than the value without electrical current. The wear rate of the contact strip increases with the increase of the sliding speed and electrical current density. The main wear mechanism of RMPCS against copper without electrical current is low stress grain abrasive and slightly adhesive wear, while arc erosion wear and oxidation wear are the dominate mechanism with electrical current, which is accompanied by adhesive wear during the process of wear.

  9. Standard test method for ranking resistance of materials to sliding wear using block-on-ring wear test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of materials to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank pairs of materials according to their sliding wear characteristics under various conditions. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. However, the interlaboratory testing has been limited to metals. In addition, the test can be run with various lubricants, liquids, or gaseous atmospheres, as desired, to simulate service conditions. Rotational speed and load can also be varied to better correspond to service requirements. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. Wear test results are reported as the volume loss in cubic millimetres for both the block and ring. Materials...

  10. Current concepts on the management of tooth wear: part 1. Assessment, treatment planning and strategies for the prevention and the passive management of tooth wear.

    Science.gov (United States)

    Mehta, S B; Banerji, S; Millar, B J; Suarez-Feito, J-M

    2012-01-13

    The aim of this series of four articles on tooth wear management is to provide the reader with the necessary information in order to be able to successfully manage cases of tooth wear, regardless of the cause, severity and location of the wear pattern seen. The content will largely focus on contemporary clinical techniques, illustrated where possible by case examples. Emphasis will be placed on 'additive adhesive techniques' utilising fixed prosthodontic protocols; however, cases of tooth wear amongst partially dentate patients involving the use of removable prostheses will also be described. The importance of patient consent and contingency planning will also be discussed. Paper 1 will describe the assessment of the wear patient, including the rationale for the planning of dental care. Also discussed will be the administration of preventative and passive management strategies for cases displaying tooth wear.

  11. Influence of carbon content on wear resistance and wear mechanism of Mn13Cr2 and Mn18Cr2 cast steels

    Directory of Open Access Journals (Sweden)

    Ding-shan Lu

    2015-01-01

    Full Text Available By means of impact abrasion tests, micro-hardness tests, and worn surface morphology observation via SEM, a comparison research based upon different impact abrasive wear conditions was conducted in this research to study the influence of different carbon contents (1.25wt.%, 1.35wt.%, and 1.45 wt.% on the wear resistance and wear mechanism of water-quenched Mn13Cr2 and Mn18Cr2 cast steels. The research results show that the wear resistance of the Mn18Cr2 cast steel is superior to that of the Mn13Cr2 cast steel under the condition of the same carbon content and different impact abrasive wear conditions because the Mn18Cr2 cast steel possesses higher worn work hardening capacity as well as a more desirable combination of high hardness and impact toughness than that of the Mn13Cr2 cast steel. When a 4.5 J impact abrasive load is applied, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the former dominates. When the carbon content is increased, the worn work hardening effect becomes increasingly dramatic, while the wear resistance of both steels decreases, which implies that an increase in impact toughness is beneficial to improving the wear resistance under severe impact abrasive wear conditions. Under the condition of a 1.0 J impact abrasive load, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the latter plays a leading role. The worn work hardening effect and wear resistance intensify when the carbon content is increased, which implies that a higher hardness can be conducive to better wear resistance under low impact abrasive condition.

  12. Effect of heat treatment on the wear resistance of high-carbon and high-nitrogen steels subjected to abrasive wear

    Science.gov (United States)

    Filippov, M. A.; Belozerova, T. A.; Blinov, V. M.; Kostina, M. A.; Val'kov, E. V.

    2006-03-01

    The effect of quenching and tempering on the capacity of steels based on chromium-carbon, chromium-nitrogen, and carbon-manganese austenite for strain-induced martensitic transformation, hardening, and wear resistance in the process of abrasive wear is studied. The steels contain 1-1.2% C or N and 18% Cr or Mn. The wear resistance of the studied steels having a structure of metastable austenite is compared to that of steel 110G13.

  13. Wear behaviour of wear-resistant adaptive nano-multilayered Ti-Al-Mo-N coatings

    Science.gov (United States)

    Sergevnin, V. S.; Blinkov, I. V.; Volkhonskii, A. O.; Belov, D. S.; Kuznetsov, D. V.; Gorshenkov, M. V.; Skryleva, E. A.

    2016-12-01

    Coating samples in the Ti-Al-Mo-N system were obtained by arc-PVD method at variable bias voltage Ub applied to the substrate, and the partial pressure of nitrogen P(N2) used as a reaction gas. The deposited coatings were characterized by a nanocrystalline structure with an average grain size of 30-40 nm and multilayered architecture with alternating layers of (Ti,Al)N nitride and Mo-containing phases with a thickness comparable to the grain size. Coatings of (Ti,Al)N-Mo-Mo2N and (Ti,Al)N-Mo2N compositions were obtained by changing deposition parameters. The obtained coatings had hardness of 40 GPa and the relative plastic deformation under microindentation up to 60%. (Ti,Al)N-Mo2N coatings demonstrated better physicomechanical characteristics, showing high resistance to crack formation and destruction through the plastic deformation mechanism without brittle fracturing, unlike (Ti,Al)N-Mo-Mo2N. The friction coefficient of the study coatings (against Al2O3 balls under dry condition using a pin-on-disc method) reached the values of 0.35 and 0.5 at 20 °C and 500 °C respectively, without noticeable wear within this temperature range. These tribological properties were achieved by forming MoO3 acting as a solid lubricant. At higher temperatures the deterioration in the tribological properties is due to the high rate of MoO3 sublimation from friction surfaces.

  14. Effect of bionic coupling units' forms on wear resistance of gray cast iron under dry linear reciprocating sliding condition

    Science.gov (United States)

    Pang, Zuobo; Zhou, Hong; Xie, Guofeng; Cong, Dalong; Meng, Chao; Ren, Luquan

    2015-07-01

    In order to get close to the wear form of guide rails, the homemade linear reciprocating wear testing machine was used for the wear test. In order to improve the wear-resistance of gray cast iron guide rail, bionic coupling units of different forms were manufactured by a laser. Wear behavior of gray-cast-iron with bionic-coupling units has been studied under dry sliding condition at room temperature using the wear testing machine. The wear resistance was evaluated by means of weight loss measurement and wear morphology. The results indicated that bionic coupling unit could improve the wear resistance of gray cast iron. The wear resistance of gray cast iron with reticulation bionic coupling unit is the best. When the load and speed changed, reticulation bionic coupling unit still has excellent performance in improving the wear resistance of gray cast iron.

  15. Reliability of an occlusal and nonocclusal tooth wear grading system: clinical use versus dental cast assessment.

    Science.gov (United States)

    Wetselaar, Peter; Lobbezoo, Frank; Koutris, Michail; Visscher, Corine M; Naeije, Machiel

    2009-01-01

    The reliability of a newly developed tooth wear grading system was assessed both clinically and on dental casts by two observers using 20 participants. The reliability of clinical occlusal/incisal tooth wear grading was fair-to-good to excellent, while that of most of the clinical nonocclusal/nonincisal grades was at least fair-to-good. Dental cast assessment frequently yielded poor reliabilities, especially for nonocclusal/nonincisal surfaces. Hence, occlusal/incisal wear could be graded more reliably than nonocclusal/nonincisal wear, while the clinical assessment of tooth wear was more reliable than the grading of dental casts.

  16. Experimental and numerical study on casing wear in highly deviated drilling for oil and gas

    Directory of Open Access Journals (Sweden)

    Hao Yu

    2016-06-01

    Full Text Available Aimed at studying the casing wear in the highly deviated well drilling, the experimental study on the casing wear was carried out in the first place. According to the test data and the linear wear model based on the energy dissipation proposed by White and Dawson, the tool joint–casing wear coefficient was obtained. The finite element model for casing wear mechanism research was established using ABAQUS. The nodal movement of the contact surface was employed to simulate the evolution of the wear depth, exploiting the Umeshmotion user subroutine. In addition, the time-dependent geometry of the contact surfaces between the tool joint and casing was being updated continuously. Consequently, the contact area and contact pressure were changed continuously during the casing wear process, which gives a more realistic simulation. Based on the shapes of worn casing, the numerical simulation research was carried out to determine the remaining collapse strength. Then the change curve of the maximum casing wear depth with time was obtained. Besides, the relationship between the maximum wear depth and remaining collapse strength was established to predict the maximum wear depth and the remaining strength of the casing after a period of accumulative wear, providing a theoretical basis for the safety assessment of worn casing.

  17. Wear Resistance of 3Cr2W8V Rough Surfaces

    Institute of Scientific and Technical Information of China (English)

    Zhou Hong; Wang Wei; Ren Lu-quan; Li Yue; Li Chen

    2005-01-01

    Three types of rough surface were processed by laser irradiation on the 3Cr2W8V material hot-work die steel surface.The wear experiments with smooth surface and rough surface samples were repeated on the pin-tray wear machine. According to the wear results, we studied the regularity of wear resistance of different rough surface samples. The results indicated that bionic rough surface can improve the wear resistance of the material and the wear resistance can be increased 1 -2times, compared with the smooth surface. Also, the wear resistance of the rough surface was affected by laser current and duration of impulse. The bigger the laser current or the impulse duration, the better is the wear resistance. When the distance between the same kind of units which are distributed on the surfaces is changed, the wear resistance changes. The wear resistance of a bionic rough surface on which the grid units were distributed at spacing of 1 mm was the best. And we designed the wear models.

  18. Experimental Study of the Hygrothermal Effect on Wear Behavior of Composite Materials

    Directory of Open Access Journals (Sweden)

    Fadhel Abbas. Abdulla

    2017-07-01

    Full Text Available The hygrothermal effect on the wear behavior of composite material (fiberglass and polyester resin vf=40% was investigated experimentally in this work. The study includes manufacturing of test device (pin on disc according to ASTM G 99. In order to study the hygrothermal effect on wear behavior of composite materials the hygrothermal chamber was manufactured. The experimental results show that the wear of glass fiber/polyester increased with increasing the load, sliding speed and sliding distance. The load and sliding distance were more effective on the wear of the composite rather than sliding speed. Also, it has been revealed that, the hygrothermal is considerable effect that, the wear rate of glass fiber/polyester without hygrothermal effect is lower than wear with hygrothermal effect. Applied load is the wear factor that has the highest physical influence on the wear of composites materials than other wear factors. Also, the wear of glass fiber/polyester without hygrothermal effect is lower than wear with hygrothermal effect.

  19. Wear Behavior and Mechanism of H13 Steel in Different Environmental Media

    Science.gov (United States)

    Li, Xinxing; Zhou, Yin; Cao, Huan; Li, Yixian; Wang, Lan; Wang, Shuqi

    2016-10-01

    Sliding wear tests were performed for H13 steel in atmosphere, distilled water, 3.5% NaCl, and 5% NaOH water solutions under various loads on a pin-on-disk wear tester. The results showed that for different environmental media, the wear rate of H13 steel in atmosphere was the maximum and that in 3.5% NaCl solution was the minimum. The maximum wear rate in atmosphere was caused by a larger quantity of heat produced in the friction process. In this case, the adhesive wear prevailed. In three wet environments, the mild wear prevailed due to the good lubrication and cooling capacity of media as well as corrosion product film on worn surface. In distilled water, the wear mechanism was a typical fatigue wear. On the other hand, in 3.5% NaCl and 5% NaOH solutions, corrosive wear prevailed. The minimum wear rate in 3.5% NaCl solution was attributed to the protective function of corrosion product film. On the contrary, noncompact corrosion product film in 5% NaOH solution resulted in higher wear rate.

  20. Influence of applied load on wear behavior of C/C-Cu composites under electric current

    Directory of Open Access Journals (Sweden)

    Jian Yin

    2017-04-01

    Full Text Available Using carbon fiber needled fabrics with Cu-mesh and graphite powder as the preform, Cu mesh modified carbon/carbon(C/C-Cu composites were prepared by chemical vapor deposition (CVD with C3H6 and impregnation-carbonization (I/C with furan resin. C/C composites, as a comparison, were also prepared. Their microstructures and wear morphologies were observed by optical microscopy (OM and scanning electron microscope (SEM, respectively. Wear behavior of C/C and C/C-Cu composites under different applied loads were investigated on a pin-on-disc wear tester. The results show that Cu meshes are well dispersed and pyrolytic carbon is in rough laminar structure. Both C/C and C/C-Cu composites had good wear properties. The current-carrying capacity of C/C-Cu composites increases and the arc discharge is hindered as the applied load increases from 40 N to 80 N. Both C/C and C/C-Cu composites had good wear properties. The mass wear rate of C/C-Cu composites under 80 N was only 4.2% of that under 60 N. In addition, C/C-Cu composites represent different wear behaviors because wear mechanisms of arc erosion, abrasive wear, adhesive wear, and oxidative wear are changing under different applied loads.

  1. Friction and wear behavior of steam-oxidized ferrous PM compacts

    Energy Technology Data Exchange (ETDEWEB)

    Raj, P. Philomen-D-Anaand; GopalaKrishna, A. [Dept. of Mechanical Engineering, Jawaharlal Nehru Technological University, Kakinada (India); Palaniradja, K [Dept. of Mechanical Engineering, Pondicherry Engineering College, Pondicherry (India)

    2016-10-15

    This study determines density effect by assessing sintering temperature and graphite content on the dry sliding wear characteristics of steam-treated iron materials using a pin-on-disk wear test. The specimens were prepared from atomized premixed iron base powders and contained 0.1 to 1.0 wt.% carbon compacted at different densities (5.9 g/cc to 6.8 g/cc). The specimens were sintered for 1 h at different sintering temperatures (1090°C to 1130°C), and then subjected to continuous steam treatment at 540°C for 95 min through in situ Powder metallurgy (PM) technique. Steam treatment was proposed to improve the wear performances of the components of PM. Wear tests were conducted using a pin-on-disk-type machine. Load ranged from 20 N to 60 N. Sliding distance and sliding velocity of 312 m and 0.26 m/s, respectively, were adopted for all tests. Scanning electron microscope was used to analyze wear surface. Increased density and graphite content reduced the wear rate of steam-treated materials. Hardness increased with increasing graphite content. Wear mechanism, wear rate map, and wear maps were drawn for the test result data. Wear transition map identified mild, severe, and ultra-severe wear regimes as functions of applied load.

  2. A novel formulation for scratch-based wear modelling in total hip arthroplasty.

    Science.gov (United States)

    Kruger, Karen M; Tikekar, Nishant M; Heiner, Anneliese D; Baer, Thomas E; Lannutti, John J; Callaghan, John J; Brown, Thomas D

    2014-01-01

    Damage to the femoral head in total hip arthroplasty often takes the form of discrete scratches, which can lead to dramatic wear acceleration of the polyethylene (PE) liner. Here, a novel formulation is reported for finite element (FE) analysis of wear acceleration due to scratch damage. A diffused-light photography technique was used to globally locate areas of damage, providing guidance for usage of high-magnification optical profilometry to determine individual scratch morphology. This multiscale image combination allowed comprehensive input of scratch-based damage patterns to an FE Archard wear model, to determine the wear acceleration associated with specific retrieval femoral heads. The wear algorithm imposed correspondingly elevated wear factors on areas of PE incrementally overpassed by individual scratches. Physical validation was provided by agreement with experimental data for custom-ruled scratch patterns. Illustrative wear acceleration results are presented for four retrieval femoral heads.

  3. Friction and Wear Behavior of GCr15 Under Multiple Movement Condition

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Friction and wear of GCr15 under cross-sliding condition is tested on a ball-on-disc wear test machine. This result shows that the cross-sliding of friction pair leads to different friction and wear behavior. For the condition described in this paper, the friction coefficients with ball reciprocating are smaller than that without ball reciprocating. The friction coefficients increase with the increase of reciprocating frequency.. The wear weight loss of the ball subjected reciprocating sliding decreases, however, the wear weight loss of disc against the reciprocating ball increases. In cross-sliding friction, the worn surfaces of the ball show crinkle appearance along the circumferential sliding traces. Delaminating of small strip debris is formed along the plowing traces on the disc worn surface. The plowing furrow on the disc surfaces looks deeper and wider than that without reciprocating sliding. The size of wear particles from cross-sliding wear is larger than those without reciprocating sliding.

  4. Toward Zero Micro/Macro-Scale Wear Using Periodic Nano-Layered Coatings.

    Science.gov (United States)

    Penkov, Oleksiy V; Devizenko, Alexander Yu; Khadem, Mahdi; Zubarev, Evgeniy N; Kondratenko, Valeriy V; Kim, Dae-Eun

    2015-08-19

    Wear is an important phenomenon that affects the efficiency and life of all moving machines. In this regard, extensive efforts have been devoted to achieve the lowest possible wear in sliding systems. With the advent of novel materials in recent years, technology is moving toward realization of zero wear. Here, we report on the development of new functional coatings comprising periodically stacked nanolayers of amorphous carbon and cobalt that are extremely wear resistant at the micro and macro scale. Because of their unique structure, these coatings simultaneously provide high elasticity and ultrahigh shear strength. As a result, almost zero wear was observed even after one million sliding cycles without any lubrication. The wear rate was reduced by 8-10-fold compared with the best previously reported data on extremely low wear materials.

  5. Investigation into the high temperature wear properties of alloys contacting against different counterfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wood, P.D.; Datta, P.K.; Burnell-Gray, J.S. [Northumbria Univ., Newcastle (United Kingdom). Surface Eng. Res. Group; Wood, N.

    1997-12-31

    Wear tests have been conducted on a reciprocating high temperature rig at 750 C and a load of 7N using a stellite 6 and incoloy 800 counterface. The ODS alloys (MA956, PM2000 and PM2000SD) all showed poor wear resistance and the absence of glaze formation when worn against Incoloy 800. Glaze formation occurred when the ODS alloys were tested againststellite 6 providing very good wear protection. Nimonic 80A tested under similar conditions exhibited good wear resistance against Incoloy 800 (presence of glazes) and poor wear resistance against stellite 6 (absence of glazes). Titanium aluminide showed very good wear resistance when tested against incoloy 800 and stellite 6. In both cases, the glaze and underlying oxide particles were entirely formed from the counterface material. These results show the strong influence of the counterface materials on the formation of wear resistant glazes. (orig.) 5 refs.

  6. Friction and Wear Characteristics of Mg-Al Alloy Containing Rare Earths

    Institute of Scientific and Technical Information of China (English)

    祁庆琚; 刘勇兵; 杨晓红

    2003-01-01

    The influence of rare earth on the friction and wear characteristics of magnesium alloy AZ91 and AM60 were studied. The results show that the wear resistance properties of rare earth magnesium alloys are better than those of matrix alloy under the testing conditions. The anti-wear behaviour of AZ91 alloy is much better than that of AM60 alloy. In dry sliding process,magnesium alloys undergo a transition from mild wear to severe wear. The addition of rare earths refine the structure of alloys, improve the comprehensive behaviors of magnesium alloys, increase the stability of oxidation films on worn surfaces, enhance the loading ability of rare earth magnesium alloys, and delay the transition from mild wear to severe wear effectively.

  7. Wear and cutting performance of diamond composite material-a comparison with tungsten carbide

    Institute of Scientific and Technical Information of China (English)

    LI Xing-sheng; J. N. Boland

    2004-01-01

    A series of wear and rock cutting tests were undertaken to assess the wear and cutting performance of a thermally stable diamond composite (TSDC). The wear tests were conducted on a newly designed wear testing rig in which a rotating aluminium oxide grinding wheel is turned (also known as machined) by the testing tool element.The rock cutting tests were performed on a linear rock-cutting planer. The thrust and cutting forces acting on the tool were measured during these tests. A tungsten carbide element was also studied for comparative purposes. The wear coefficients of both materials were used to evaluate wear performance while cutting performance was assessed by tool wear and the rates of increase in forces with cutting distance.

  8. Sliding wear and friction behavior of zirconium alloy with heat-treated Inconel718

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.H., E-mail: kimjhoon@cnu.ac.kr [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.M. [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.K.; Jeon, K.L. [Nuclear Fuel Technology Department, Korea Nuclear Fuel, 1047 Daedukdae-ro, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2014-04-01

    In water-cooled nuclear reactors, the sliding of fuel rod can lead to severe wear and it is an important issue to sustain the structural integrity of nuclear reactor. In the present study, sliding wear behavior of zirconium alloy in dry and water environment using Pin-On-Disk sliding wear tester was investigated. Wear resistance of zirconium alloy against heat-treated Inconel718 pin was examined at room temperature. Sliding wear tests were carried out at different sliding distance, axial load and sliding speed based on ASTM (G99-05). The results of these experiments were verified with specific wear rate and coefficient of friction. The micro-mechanisms responsible for wear in zirconium alloy were identified to be microcutting and microcracking in dry environment. Moreover, micropitting and delamination were observed in water environment.

  9. Dry sliding wear behavior of Ti-6Al-4V alloy in air

    Institute of Scientific and Technical Information of China (English)

    刘勇; 杨德庄; 武万良; 杨士勤

    2002-01-01

    The dry sliding wear properties of Ti-6Al-4V alloy sliding against GCr15 steel under different velocities(between 0.2 and 1.2 m/s)and applied loads(from 30 to 90 N)were tested using a pin-on-disk tester in air. The wear occurred on both surfaces of the tested couplings. The wear rate of the Ti-6Al-4V alloy ranged from 23.0 to 123.8 mg/km. The wear of Ti-6Al-4V samples was in severe wear. The wear rate of Ti-6Al-4V samples increased with the increasing of load and shows a minimum on the curves of wear rate versus sliding velocity. SEM morphologies of worn surfaces and debris were observed. Phases in the debris were analyzed by means of XRD spectra.

  10. Characterization and Empirical Modelling of Sliding Wear on Sintered Aluminium-Graphite Composites

    Directory of Open Access Journals (Sweden)

    Amrishraj Doraisamy

    2014-01-01

    Full Text Available Aluminium-graphite composites were synthesized using powder metallurgy route. Graphite was added as reinforcement in the range of 0, 3, and 6 weight % and composites were prepared by P/M. Microstructural analysis of the newly synthesized composites was carried out using SEM. The hardness of the composites was studied using Vickers microhardness tester, by applying a load of 1 kg for 5 sec. Also the amount of porosity was determined. Further the wear test was conducted on the sintered specimens using pin-on-disc wear apparatus according to ASTM-G99 standards. A regression model was developed to predict the wear rate of the specimen. Then the worn images were studied using SEM based on response surface methodology in order to understand the various wear mechanisms involved. The study revealed that mild wear, oxidational wear, plowing, cutting, and plastic deformation are the main mechanisms responsible for causing the wear.

  11. Field investigation on effects of railway track geometric parameters on rail wear

    Institute of Scientific and Technical Information of China (English)

    SADEGHI J.; AKBARI B.

    2006-01-01

    Rail wear has dramatic impact on track performance, ride quality and maintenance costs. The amount of rail wear is influenced by various elements among which geometric parameters play an important role. The amount of wear in Iran's railway lines and its imposed maintenance costs oblige us to make modifications on the various geometrical parameters. In order to ensure the effectiveness of these changes, it is necessary to investigate these parameters and their effects on the wear. This research is aimed at studying the effects of different track geometrical parameters on the vertical and lateral wear by conducting a three phase field investigation. The first phase was carried out at the switches of a station, the second phase at a straight line, and the third at a curved line out of the station. The results obtained are analyzed and the role of each track geometrical parameter in the rail wear is discussed. Recommendations for prevention or reduction of rail wear are presented.

  12. Microstructural effects on the sliding wear resistance of a cobalt-based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frenk, A. (Dept. of Materials, Swiss Federal Inst. of Technology, Lausanne (Switzerland)); Kurz, W. (Dept. of Materials, Swiss Federal Inst. of Technology, Lausanne (Switzerland))

    1994-05-01

    The influence of the microstructure on the dry sliding wear resistance of a hypo-eutectic Stellite 6 alloy was investigated under conditions leading to severe metallic wear of the hardfacing alloy. Conventional chill casting as well as laser surface cladding were used to produce a wide range of solidification microstructures. The hardness of the alloy was strongly dependent on the microstructure and in particular on the size of the dendrites. Under the sliding conditions investigated, severe delamination wear of the Stellite occurred. High coefficients of friction were measured and the structure in the subsurface was completely destroyed by the resulting stress cycles. During the stationary wear regime, no dependence of the wear rate on the as-solidified microstructure could therefore be determined. However, a strong influence on the wear resistance of alloying elements which affect the matrix properties was observed. Suggestions are made for the improvement of the wear resistance of such alloys under similar sliding conditions. (orig.)

  13. Wear Performance of UHMWPE and Reinforced UHMWPE Composites in Arthroplasty Applications: A Review

    Directory of Open Access Journals (Sweden)

    Juan C. Baena

    2015-05-01

    Full Text Available As the gold standard material for artificial joints, ultra-high-molecular-weight polyethylene (UHMWPE generates wear debris when the material is used in arthroplasty applications. Due to the adverse reactions of UHMWPE wear debris with surrounding tissues, the life time of UHMWPE joints is often limited to 15–20 years. To improve the wear resistance and performance of the material, various attempts have been made in the past decades. This paper reviews existing improvements made to enhance its mechanical properties and wear resistance. They include using gamma irradiation to promote the cross-linked structure and to improve the wear resistance, blending vitamin E to protect the UHMWPE, filler incorporation to improve the mechanical and wear performance, and surface texturing to improve the lubrication condition and to reduce wear. Limitations of existing work and future studies are also identified.

  14. Evaluation of sliding wear behavior of graphite particle-containing magnesium alloy composites

    Institute of Scientific and Technical Information of China (English)

    QI Qing-ju

    2006-01-01

    The influence of graphite particle content on the friction and wear characteristics of AZ91 magnesium alloy matrix composite was studied. The results show that the wear resistances of graphite-containing composite are much better than those of the matrix under the test conditions. The anti-wear ability of magnesium alloy composite is improved substantially with the increase of the graphite content from 5% to 20%, and both wear mass loss and coefficient of friction are decreased to low level. Different wear mechanisms operate at different sliding stages. A continuous black lubricating film forms progressively on the worn surface along sliding, which effectively limits the direct interaction between the composite tribosurface and the counterpart, and also remarkably delays the transition from mild wear to severe wear for magnesium alloy composite.

  15. High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-06-01

    Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

  16. Carbon-Based Wear Coatings: Properties and Applications

    Science.gov (United States)

    Miyoshi, Kazuhisa

    2003-01-01

    The technical function of numerous engineering systems - such as vehicles, machines, and instruments - depends on the processes of motion and on the surface systems. Many processes in nature and technology depend on the motion and dynamic behavior of solids, liquids, and gases. Smart surface systems are essential because of the recent technological push toward higher speeds, loads, and operating temperatures; longer life; lighter weight and smaller size (including nanotechnology); and harsh environments in mechanical, mechatronic, and biomechanical systems. If proper attention is not given to surface systems, then vehicles, machines, instruments, and other technical systems could have short lives, consume excessive energy, experience breakdowns, result in liabilities, and fail to accomplish their missions. Surface systems strongly affect our national economy and our lifestyles. At the NASA Glenn Research Center, we believe that proper attention to surface systems, especially in education, research, and application, could lead to economic savings of between 1.3 and 1.6 percent of the gross domestic product. Wear coatings and surface systems continue to experience rapid growth as new coating and surface engineering technologies are discovered, more cost-effective coating and surface engineering solutions are developed, and marketers aggressively pursue, uncover, and exploit new applications for engineered surface systems in cutting tools and wear components. Wear coatings and smart surface systems have been used widely in industrial, consumer, automotive, aerospace, and biomedical applications. This presentation expresses the author's views of and insights into smart surface systems in wear coatings. A revolution is taking place in carbon science and technology. Diamond, an allotrope of carbon, joins graphite, fullerenes, and nanotubes as its major pure carbon structures. It has a unique combination of extreme properties: hardness and abrasion resistance; adhesion

  17. Wear Characteristics of Oleophobic Coatings in Aerospace Applications

    Science.gov (United States)

    Shams, Hamza; Basit, Kanza

    2016-05-01

    This paper investigates the wear characteristics of oleophobic coatings when applied over Inconel 718, which has widespread applications in the aerospace industry. Coatings once applied were selectively exposed to controlled uni-and then multi-directional stand storm conditions. Size and speed of sand particles colliding with the work surface were carefully moderated to simulate sand storm conditions. Study of friction was performed using Lateral Force Microscopy (LFM) coupled with standard optical microscopy. The analysis has been used to devise a coefficient of friction value and in turn suggest wear behavior of the coated surface including the time associated with exposure of the base substrate. The analysis after validation aims to suggest methods for safe usage of these coatings for aerospace applications.

  18. The Investigation of EDM Parameters on Electrode Wear Ratio

    Directory of Open Access Journals (Sweden)

    Reza Atefi

    2012-05-01

    Full Text Available Electrical Discharge Machining (EDM is a well-established machining option for manufacturing geometrically complex or hard material parts that are extremely difficult-to-machine by conventional machining processes. The non-contact machining technique has been continuously evolving from a mere tool and die making process. In this study, the influence of different electro discharge machining parameters (current, pulse on-time, pulse off-time, arc voltage on the electrode wear ratio as a result of application copper electrode to hot work steel DIN1.2344 has been investigated. Design of the experiment was chosen as full factorial. Artificial neural network has been used to choose proper machining parameters and to reach certain electrode wear ratio. Finally a hybrid model has been designed to reduce the artificial neural network errors. The experiment results indicated a good performance of proposed method in optimization of such a complex and non-linear problems.

  19. The role of oxidation in the fretting wear process

    Science.gov (United States)

    Bill, R. C.

    1980-01-01

    Fretting experiments were conducted on titanium, a series of Ni-Cr-Al alloys and on some high temperature turbine alloys at room temperature and at elevated temperatures in air and in various inert environments. It was found that, depending on temperature and environment, the fretting behavior of the materials examined could be classified according to four general types of behavior. Briefly, these types of behavior were: (1) the complete absence of oxidation, as in inert environments, generally leading to low rates of fretting wear but high fretting friction; (2) gradual attrition of surface oxide with each fretting stroke, found in these experiments to operate in concert with other dominating mechanisms; (3) rapid oxidation at surface fatigue damage sites, resulting in undermining and rapid disintegration of the load bearing surface; and (4) the formation of coherent, protective oxide film, resulting in low rates of fretting wear. An analytical model predicting conditions favorable to the fourth type of behavior was outlined.

  20. Study of Stainless Steel Resistance in Conditions of Tribocorrosion Wear

    Directory of Open Access Journals (Sweden)

    Goran Rozing

    2015-07-01

    Full Text Available Analyzed was the influence of tribocorrosion wear due to effects of fatty acids present in the processed medium. The analysis was conducted on samples made of two austenitic and two martensitic stainless steels. Austenitic steels were tested in their nitrided state and martensitic in their induction hardened state. Conducted were laboratory tests of corrosion resistance of samples, analysis of the microstructure and hardness. To see how the applied processes for modifying the surface of stainless steels behave in realistic conditions, it was conducted the examination of samples/parts of a sunflower cake chain conveyer. Based on the comparison of results obtained in the laboratory and in real conditions, it was estimated that steels AISI 420 and AISI 431 with induction hardened surfaces have a satisfactory resistance to abrasive-adhesive wear in the presence of fatty acids.

  1. Predicting bicycle helmet wearing intentions and behavior among adolescents.

    Science.gov (United States)

    O'Callaghan, Frances V; Nausbaum, Sarah

    2006-01-01

    Cycling accidents in Australia, especially those resulting in head injuries, are a substantive cause of death and disability; but despite legislation and evidence that helmets reduce the risk of head injury, few adolescents wear them. This study employed a revised version of the Theory of Planned Behavior (TPB; [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211]) to investigate the determinants of helmet use among a sample of adolescents. Participants in the initial data collection were 294 high school students in Year 8 and Year 11, with 266 completing a follow-up questionnaire measuring behavior over the previous two weeks. Social norms, perceptions of control, and past behavior significantly predicted intentions to use helmets and perceptions of control and past behavior predicted actual helmet use. Strengthening the routine of helmet use and building young people's confidence that they can overcome any perceived barriers to helmet use will improve adherence to helmet wearing behavior.

  2. Carbon-Based Wear Coatings: Properties and Applications

    Science.gov (United States)

    Miyoshi, Kazuhisa

    2003-01-01

    The technical function of numerous engineering systems - such as vehicles, machines, and instruments - depends on the processes of motion and on the surface systems. Many processes in nature and technology depend on the motion and dynamic behavior of solids, liquids, and gases. Smart surface systems are essential because of the recent technological push toward higher speeds, loads, and operating temperatures; longer life; lighter weight and smaller size (including nanotechnology); and harsh environments in mechanical, mechatronic, and biomechanical systems. If proper attention is not given to surface systems, then vehicles, machines, instruments, and other technical systems could have short lives, consume excessive energy, experience breakdowns, result in liabilities, and fail to accomplish their missions. Surface systems strongly affect our national economy and our lifestyles. At the NASA Glenn Research Center, we believe that proper attention to surface systems, especially in education, research, and application, could lead to economic savings of between 1.3 and 1.6 percent of the gross domestic product. Wear coatings and surface systems continue to experience rapid growth as new coating and surface engineering technologies are discovered, more cost-effective coating and surface engineering solutions are developed, and marketers aggressively pursue, uncover, and exploit new applications for engineered surface systems in cutting tools and wear components. Wear coatings and smart surface systems have been used widely in industrial, consumer, automotive, aerospace, and biomedical applications. This presentation expresses the author's views of and insights into smart surface systems in wear coatings. A revolution is taking place in carbon science and technology. Diamond, an allotrope of carbon, joins graphite, fullerenes, and nanotubes as its major pure carbon structures. It has a unique combination of extreme properties: hardness and abrasion resistance; adhesion

  3. Composites for Increased Wear Resistance: Current Achievements and Future Prospects

    Science.gov (United States)

    Lancaster, J. K.

    1984-01-01

    The various ways in which reductions in wear and/or friction can be achieved by the use of composite materials are reviewed. Reinforced plastics are emphasized and it is shown that fillers and fibers reduce wear via several mechanisms additional to their role of increasing overall mechanical strength, preferential transfer, counter face abrasion, preferential load support, or third-body formation on either the composite or its counterface. Examples are given from recent work on thin layer composites of the type widely used as dry bearings in aircraft flight control mechanisms. Developments in metal based composites and carbon-carbon composites for high energy brakes are discussed. The aspects which could benefit by increased fundamental understanding identified and the types of composites which appear to have greatest potential for further growth are indicated.

  4. Wear of connector contacts exposed to relative motion

    Science.gov (United States)

    Wilk, R. A.

    Connectors play a significant role in the performance, cost, and reliability of electronic equipment. In connection with the development of the system interconnection design, a factor which is often overlooked is related to the importance of connector selection and mounting to minimize relative motion between contacts during vibration encountered in handling, transportation, and service. This motion can lead to the loss of protective coatings (gold and nickel) due to frictional wear. If this happens, fretting corrosion of the base metals may occur. The produced damage can adversely affect performance due to increased joint resistance, eventually causing intermittent contacts. The present investigation is concerned with the study of different style contacts (tuning fork, box, and circular) to determine their endurance and wear characteristics when exposed to relative motion created by vibration. All contacts investigated were fabricated from brass, beryllium copper, or phosphor bronze, and had .00127 mm minimum gold plating over .00127 mm minimum nickel plating.

  5. Evaluating lubricant performance by 3D profilometry of wear scars

    Science.gov (United States)

    Georgescu, C.; Deleanu, L.; Pirvu, C.

    2016-08-01

    Due to improvement in analysing surface texture and optical instruments for investigating the texture surface, the authors propose to evaluate the lubricant performance by analysing the change in several 3D parameters in comparison to an analysis on 2D profile. All the surface of the wear scar generated on the four ball machine is investigated and the conclusion is that from the tribological point of view, the 3D parameters reflect better the surface quality evolution after testing. Investigation was done on the wear scars generated on the three fixed balls, for five lubricants: a non-additivated transmission mineral oil (T90), two grades of rapeseed oil (coarse degummed and refined) and two grades of soybean oil (coarse and degummed).

  6. Influence of quartz particles on wear in vertical roller mills

    DEFF Research Database (Denmark)

    Jensen, Lucas R.D.; Friis, Henrik; Fundal, Erling;

    2010-01-01

    statistical planning, a total of 10 tests were arried out with two different limestones and one type of quartz sand. The size distributions were kept constant and only the mixing ratios were varied. It appears from the investigation that mixtures consisting of minerals with different grindabilities result...... in an increased concentration of abrasive particles in the grinding bed ðR2 > 0:99Þ. The present study shows that the quartz concentration in the grinding bed is determining the wear rate....

  7. Abrasive Wear of Alloyed Cast Steels Applied for Heavy Machinery

    Directory of Open Access Journals (Sweden)

    Studnicki A.

    2015-03-01

    Full Text Available In the paper the results and analysis of abrasive wear studies were shown for two grades of cast steels: low-alloyed cast steel applied for heavy machinery parts such as housing, covers etc. and chromium cast steels applied for kinetic nodes of pin-sleeve type. Studies were performed using the modified in Department of Foundry pin-on-disc method.

  8. Pavement wear and airborne dust pollution in Norway

    OpenAIRE

    Snilsberg, Brynhild

    2008-01-01

    In several large cities in Norway the traffic volume is high. The use of studded tires and other friction enhancing measures during winter leads to significant pavement wear, which in turn leads to an increase in the amount of airborne particulate matter, often exceeding the limits set in the ambient air regulation. This represents a nuisance or health risk for people being exposed to the pollution. According to regulations set by the European Union particulate matter is measured and regulate...

  9. Sliding contacts on printed circuit boards and wear behavior

    OpenAIRE

    Le Solleu, J.-P.

    2010-01-01

    Abstract Automotive suppliers use since decades printed circuit boards (PCB) gold plating pads, as direct contact interface for low current sliding contacts. Several gold plating processes are available on the market, providing various wear behaviour. Some specific galvanic hard gold (AuCo or AuNi). plating was developed on PCB's. This specific plating generates extra costs due to the material quantity and also the process complexity. In a cost driven indust...

  10. Fundamentals of friction and wear on the nanoscale

    CERN Document Server

    Gnecco, Enrico

    2014-01-01

    This book provides an updated review on the development of scanning probe microscopy and related techniques, and the availability of computational techniques not even imaginable a few decades ago. The 36 chapters cover instrumental aspects, theoretical models and selected experimental results, thus offering a broad panoramic view on fundamental issues in nanotribology which are currently being investigated. Compared to the first edition, several topics have been added, including triboluminescence, graphene mechanics, friction and wear in liquid environments, capillary condensation, and multisc

  11. The correction of occlusal vertical dimension on tooth wear

    Directory of Open Access Journals (Sweden)

    Rostiny Rostiny

    2007-12-01

    Full Text Available The loss of occlusal vertical dimension which is caused by tooth wear is necessarily treated to regain vertical dimension. Correctional therapy should be done as early possible. In this case, simple and relatively low cost therapy was performed. In unserve loss of occlusal vertical dimension, partial removable denture could be used and the improvement of lengthening anterior teeth using composite resin to improve to regain vertical dimensional occlusion.

  12. Antifriction and wear resistance of tin diffusion coating on brass

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    After brass is coated with tin, heat treatment makes the coating metal Sn and the substrate metal lic elements Cu and Zn diffuse with each other. This causes the c oating composition to be changed and the interface to be strengthened. The diffusion coating with a multiphase structure formed by this process has excellent properties of antifriction and wear resistance. With the aid of scanning electron microscopy, electronic probe microanalysis and X-ray diffraction, the mechanism of the properties is discussed.

  13. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Mike L. Fulcher; Kenneth L. Knittel

    2004-06-08

    The work performed on this program was to develop wear resistant, tough FM composite materials with efforts focused on WC-Co based FM systems. The materials were developed for use in mining industry wear applications. Components of interest were drill bit inserts for drilling blast holes. Other component applications investigated included wear plates for a variety of equipment such as pit shovels, wear surfaces for conveyors, milling media for ball milling operations, hydrocyclone cones, grader blades and dozer teeth. Cross-cutting technologies investigated included hot metal extrusion dies, drill bits for circuit board fabrication, cutting tools for cast iron and aluminum machining. An important part of the work was identification of the standard materials used in drilling applications. A materials trade study to determine those metals and ceramics used for mining applications provided guidance for the most important materials to be investigated. WC-Co and diamond combinations were shown to have the most desirable properties. Other considerations such as fabrication technique and the ability to consolidate shifted the focus away from diamond materials and toward WC-Co. Cooperating partners such as Kennametal and Kyocera assisted with supplies, evaluations of material systems, fabricated parts and suggestions for cross-cutting technology applications for FM architectures. Kennametal provided the raw materials (WC-Co and Al-TiCN powders) for the extent of the material evaluations. Kyocera shared their research into various FM systems and provided laboratory testing of fabricated materials. Field testing provided by partners Superior Rock Bit and Brady Mining and Construction provided insight into the performance of the fabricated materials under actual operational conditions. Additional field testing of cross-cutting technology, the extrusion of hot metals, at Extruded Metals showed the potential for additional market development.

  14. Wearing tests on aluminium coated with diamond by triboadhesion

    Institute of Scientific and Technical Information of China (English)

    J.M.RodríguezLelis; B.D.Angulo; J.O.Colín; J.PorcayoCalderón

    2001-01-01

    In this work the results obtained from subjecting aluminium coated with diamond by tri-boadhesion to a wearing process with a plane rider. Here it is shown the ratio of the normal toshearing forces, called friction factor, as an indication of the resistance of the surface. It was foundthat the film of the aluminium coated with diamond resisted three times compared with the oxida-tion film of commercial aluminium, which for the purpose of this work was considered withoutcoating.

  15. Friction and wear evaluation of high-strength gel

    Science.gov (United States)

    Kameyama, Toshiki; Wada, Masato; Makino, Masato; Kawakami, Masaru; Furukawa, Hidemitsu

    2016-04-01

    In the last decade, several innovative polymer gel materials with enhanced mechanical proper ties have been invented by Japanese researches. In 2003, a most effective but simple way was proposed to synthesize double network gels, with compression fracture stress of about 30MPa, compared to several tens of kPa for common gels. In this study, we evaluate the wear of a double network gel, both with and without water lubrication. In the un-lubricated experiment, the gel surface is worn with a stainless steel ball. In the other experiment with water lubrication, the gel surface is worn by different counter surfaces because the stainless steel ball was too smooth to wear. It was found that frictional vibration of wear gel is transitioning to steady sliding in lubricated. As conventional reduction method of the friction by the contact between general solids, there are surface processing such as the texturing, attachment of lubrication materials. In the case of gel, the minute processing to the surface such as the texturing is difficult, because the gel is soft in comparison with the hard materials such as the metal. By proceeding with this study, the surface processing of low-frictional gels will be enabled.

  16. Tribopolymerization as an anti-wear mechanism. Quarterly progress report

    Energy Technology Data Exchange (ETDEWEB)

    Furey, M.J.

    1996-04-01

    The primary objective of this activity is to obtain the necessary data which would enhance, promote, and encourage the introduction of advanced lubrication technology into the marketplace. This includes (a) defining specific but different applications, (b) establishing the limits or ranges of applied loads, speeds, and temperatures over which the concept of tribopolymerization would work in reducing wear and/or friction, (c) continuing in efforts to understand the film-forming process (this rates to (b) above), using this knowledge to develop new and even more effective additives, and (d) exploring possible connections with private and investment companies for the licensing and marketing of products which will reduce friction and wear in a variety of applications. Progress was made in several different but connected areas. These included (a) establishing of load/velocity limits of selected monomers for ceramic lubrication, (b) the discovery of new and effective monomers designed for higher temperature anti-wear applications, (c) improvements and modifications of the high load/high speed pin-on-disk machine, (d) the initiation of related or spin-off projects designed to get their advanced technology into the marketplace, (e) the filing of three new patent applications, and (f) collaborative research with Dr. Kajdas--the co-inventor with Dr. Furey--on tribopolymerization as a novel and effective approach to the boundary lubrication of ceramics and steel. These and other elements of progress made during the first Quarter of 1996 are discussed briefly.

  17. A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2009-11-01

    The work summarized here comprises the concluding effort of a multi-year project, funded by the U.S. Department of Energy, Office of Vehicle Technologies. It supports the development of a better understanding of advanced diesel engine designs in which enhanced power density, energy efficiency, and emissions control place increasing demands upon the durability of engine materials. Many kinds of metallic alloys are used in engines depending on the operating stresses, temperatures, and chemical environments. Exhaust valves, for example, are subjected to high temperatures and repetitive surface contacts that place demands on durability and frictional characteristics of the materials. Valves must continue to seal the combustion chamber properly for thousands of hours of cyclic engine operation and under varying operating conditions. It was the focus of this effort to understand the wear processes in the valve-seat area and to develop a model for the surface deformation and wear of that important interface. An annotated bibliography is provided to illustrate efforts to understand valve wear and to investigate the factors of engine operation that affect its severity and physical manifestation. The project for which this modeling effort was the final task, involved construction of a high-temperature repetitive impact test system as well as basic tribology studies of the combined processes of mechanical wear plus oxidation at elevated temperatures. Several publications resulted from this work, and are cited in this report. The materials selected for the experimental work were high-performance alloys based on nickel and cobalt. In some cases, engine-tested exhaust valves were made available for wear analysis and to ensure that the modes of surface damage produced in experiments were simulative of service. New, production-grade exhaust valves were also used to prepare test specimens for experimental work along with the other alloy samples. Wear analysis of valves and seats

  18. Multiscale Modeling of Wear Degradation in Cylinder Liners

    KAUST Repository

    Moraes, Alvaro

    2014-03-20

    Every mechanical system is naturally subjected to some kind of wear process that, at some point, will cause failure in the system if no monitoring or treatment process is applied. Since failures often lead to high economical costs, it is essential both to predict and to avoid them. To achieve this, a monitoring system of the wear level should be implemented to decrease the risk of failure. In this work, we take a first step into the development of a multiscale indirect inference methodology for state-dependent Markovian pure jump processes. This allows us to model the evolution of the wear level and to identify when the system reaches some critical level that triggers a maintenance response. Since the likelihood function of a discretely observed pure jump process does not have an expression that is simple enough for standard nonsampling optimization methods, we approximate this likelihood by expressions from upscaled models of the data. We use the Master Equation (ME) to assess the goodness-of-fit and to compute the distribution of the hitting time to the critical level.

  19. Interference Assembly and Fretting Wear Analysis of Hollow Shaft

    Directory of Open Access Journals (Sweden)

    Chuanjun Han

    2014-01-01

    Full Text Available Fretting damage phenomenon often appears in the interference fit assembly. The finite element model of hollow shaft and shaft sleeve was established, and the equivalent stress and contact stress were computed after interference assembly. The assembly body of hollow shaft and shaft sleeve was in whirling bending load, and the contact status (sticking, sliding, and opening and the distribution of stress along one typical contact line were computed under different loads, interferences, hollow degrees, friction coefficient, and wear quantity. Judgment formula of contact state was fixed by introducing the corrected coefficient k. The computation results showed that the “edge effect” appears in the contact surface after interference fit. The size of slip zone is unchanged along with the increase of bending load. The greater the interference value, the bigger the wear range. The hollow degree does not influence the size of stick zone but controls the position of the junction point of slip-open. Tangential contact stress increases with the friction coefficient, which has a little effect on normal contact stress. The relationship between open size and wear capacity is approximately linear.

  20. Changes in the Eye Microbiota Associated with Contact Lens Wearing

    Directory of Open Access Journals (Sweden)

    Hakdong Shin

    2016-03-01

    Full Text Available Wearing contact lenses has been identified as a risk factor for the development of eye conditions such as giant papillary conjunctivitis and keratitis. We hypothesized that wearing contact lenses is associated with changes in the ocular microbiota. We compared the bacterial communities of the conjunctiva and skin under the eye from 58 subjects and analyzed samples from 20 subjects (9 lens wearers and 11 non-lens wearers taken at 3 time points using a 16S rRNA gene-based sequencing technique (V4 region; Illumina MiSeq. We found that using anesthetic eye drops before sampling decreases the detected ocular microbiota diversity. Compared to those from non-lens wearers, dry conjunctival swabs from lens wearers had more variable and skin-like bacterial community structures (UniFrac; P value = 3.0. The results indicate that wearing contact lenses alters the microbial structure of the ocular conjunctiva, making it more similar to that of the skin microbiota. Further research is needed to determine whether the microbiome structure provides less protection from ocular infections.

  1. Erosive wear of selected materials for fossil energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Adler, Thomas A.; Rawers, James C.; Tylczak, Joseph H.; Hawk, Jeffrey A.

    2001-01-01

    A number of materials have been evaluated to determine their erosion resistance for fossil energy applications. This is part of a larger program to study wear and corrosion at Albany Research Center. This paper will present the results for some of these materials, including FeAl, FeAl cermets, WC-Co cemented carbides, Si3N4-MoSi2, Si3N4, Stellite 6B, white cast irons and 440C steel. Trends in erosion rates due to material properties and erosive conditions will be presented. FeAl cermets performed well compared to the WC-Co cemented carbides. The interparticle spacing of the WC-Co cemented carbides correlated with the erosion rate. The erosion rate of the WC-Co cemented carbides decreased as the interparticle spacing decreased. It is important to realize that erosion resistance is not an intrinsic material property, but is a system response. A change in the wear environment can significantly alter the relative rankings of materials with respect to their wear rate. For example, at relatively low velocities, the carbides in the white cast irons are more erosion resistant than the matrix, while at higher velocities the matrix is more erosion resistant.

  2. Wear performance of garnet aluminium composites at high contact pressure

    Science.gov (United States)

    Sharma, Anju; Arora, Rama; Kumar, Suresh; Singh, Gurmel; Pandey, O. P.

    2016-05-01

    To satisfy the needs of the engineering sector, researchers and material scientists in this area adopted the development of composites with tailor made properties to enhance efficiency and cost savings in the manufacturing sector. The technology of the mineral industry is shaping the supply and demand of minerals derived materials. The composites are best classified as high performance materials have high strength-to-weight ratios, and require controlled manufacturing environments for optimum performance. Natural mineral garnet was used as the reinforcement of composite because of satisfactory mechanical properties as well as an attractive ecological alternative to others ceramics. For this purpose, samples have been prepared with different sizesof the garnet reinforcement using the mechanical stirring method to achieve the homogeneously dispersed strengthening phase. A systematic study of the effect of high contact pressure on the sliding wear behaviour of garnet reinforced LM13 alloy composites is presented in this paper. The SEM analysis of the worn samples and debris reveals the clues about the wear mechanism. The drastic improvement in the wear resistance of the composites at high contact pressure shows the high potential of the material to be used in engineering applications.

  3. Wear/comfort Pareto optimisation of bogie suspension

    Science.gov (United States)

    Milad Mousavi Bideleh, Seyed; Berbyuk, Viktor; Persson, Rickard

    2016-08-01

    Pareto optimisation of bogie suspension components is considered for a 50 degrees of freedom railway vehicle model to reduce wheel/rail contact wear and improve passenger ride comfort. Several operational scenarios including tracks with different curve radii ranging from very small radii up to straight tracks are considered for the analysis. In each case, the maximum admissible speed is applied to the vehicle. Design parameters are categorised into two levels and the wear/comfort Pareto optimisation is accordingly accomplished in a multistep manner to improve the computational efficiency. The genetic algorithm (GA) is employed to perform the multi-objective optimisation. Two suspension system configurations are considered, a symmetric and an asymmetric in which the primary or secondary suspension elements on the right- and left-hand sides of the vehicle are not the same. It is shown that the vehicle performance on curves can be significantly improved using the asymmetric suspension configuration. The Pareto-optimised values of the design parameters achieved here guarantee wear reduction and comfort improvement for railway vehicles and can also be utilised in developing the reference vehicle models for design of bogie active suspension systems.

  4. Erosion wear behaviour and mechanism of abradable seal coating

    Institute of Scientific and Technical Information of China (English)

    冉丽萍

    2002-01-01

    The erosion wear behaviour and mechanism of several middle temperature seal coatings were investigated by a CMS-100 self-made vacuum sand erosion machine. The results show that the relationship between the erosion mass loss and the erosion time is linear, the coatings hold a maximum erosion rate at 60° impact angle, and the relationship between the erosion rate and the impact speed is an exponential function. The speed exponent increases with the increase of the impact angle. At 90° impact, indentations and extruded lips were generated on the coating surface subjected to impact. With repetitive impact by the abrasive particles, the extruded lips were work-hardened and peeled off, while flattened metal phase grains were impacted repeatedly, loosed and debonded. At 30° impact, the erosion wear of the coating is characterized by micro-cutting, plowing and tunneling via pores and non-metal phase. The model of the erosion mechanism is advanced on the basis of the above-mentioned erosion wear behaviour.

  5. Association between friction and wear in diarthrodial joints lacking lubricin

    Science.gov (United States)

    Jay, Gregory D; Torres, Jahn R; Rhee, David K; Helminen, Heikki J; Hytinnen, Mika M; Cha, Chung-Ja; Elsaid, Khaled; Kim, Kyung-Suk; Cui, Yajun; Warman, Matthew L

    2007-01-01

    Objective The glycoprotein lubricin (encoded by the gene Prg4) is secreted by surface chondrocytes and synovial cells, and has been shown to reduce friction in vitro. In contrast to man-made bearings, mammalian diarthrodial joints must endogenously produce friction-reducing agents. This study was undertaken to investigate whether friction is associated with wear. Methods The lubricating ability of synovial fluid (SF) samples from humans with genetic lubricin deficiency was tested in vitro. The coefficient of friction in the knee joints of normal and lubricin-null mice was measured ex vivo; these joints were also studied by light and electron microscopy. Atomic force microscopy was used to image and measure how lubricin reduces friction in vitro. Results SF lacking lubricin failed to reduce friction in the boundary mode. Joints of lubricin-null mice showed early wear and higher friction than joints from their wild-type counterparts. Lubricin self-organized and reduced the work of adhesion between apposing asperities. Conclusion These data show that friction is coupled with wear at the cartilage surface in vivo. They imply that acquired lubricin degradation occurring in inflammatory joint diseases predisposes the cartilage to damage. Lastly, they suggest that lubricin, or similar biomolecules, will have applications in man-made devices in which reducing friction is essential. PMID:17968947

  6. Nanoscale adhesion, friction and wear of proteins on polystyrene.

    Science.gov (United States)

    Bhushan, Bharat; Utter, Jason

    2013-02-01

    Protein layers are routinely deployed on biomaterials and biological micro/nanoelectromechanical systems (bioMEMS/NEMS) as a functional layer allowing for specific molecular recognition, binding properties or to facilitate biocompatibility. In addition, uncoated biomaterial surfaces will have uncontrolled protein layers adsorbing to the surface within seconds of implantation, so a pre-defined protein layer will improve the host response. Implanted biomaterials also experience micromotion over time which may degrade any surface protein layers. Degradation of these protein layers may lead to system failure or an unwanted immune response. Therefore, it is important to characterize the interfacial properties of proteins on biomaterial surfaces. In this study, the nanoscale adhesion, friction and wear properties of proteins adsorbed to a spin coated polystyrene surface were measured using atomic force microscopy (AFM) in deionized (DI) water and phosphate buffered saline. Adhesion, friction and wear have been measured for bovine serum albumin (BSA), collagen, fibronectin and streptavidin (STA) in DI water and PBS as a function of protein concentration. These proteins were chosen due to their importance and widespread application in the biotechnology field. Adhesion and friction were also measured for BSA and STA at two different temperatures and different pH values to simulate a biological environment. Based on this study, adhesion, friction and wear mechanisms of the different proteins are discussed.

  7. Tool Wear Characteristics of Oil Palm Empty Fruit Bunch Particleboard

    Science.gov (United States)

    Ratnasingam, Jegatheswaran; Chew Tek, Tee; Farrokhpayam, Saied Reza

    A series of machining experiments on the Oil-Palm Empty Fruit Bunch (OPEFB) particleboard were carried out using a CNC router, to evaluate the tool wearing properties of the composite in comparison to the conventional wood-material particleboard. A single-fluted tungsten-carbide router bit (12 mm φ, 18 000 rpm), with a rake angle of 15° was used in this experiment, in which the depth of cut was 1.5 mm and feed speed was 4.5 m min-1. The router bit machined the edge of the board, moving along the full length before returning to repeat the cycle. The tool was examined for the extent of wear after complete failure had occurred. The result found that the wear pattern was similar in the oil-palm based particleboard and the wood-based particleboard, but the former was twice more abrasive compared to the latter. Microscopic examination of the cutter edge revealed greater incidence of micro-fracture when cutting the oil-palm based particleboard, indicating the presence of hard impurities in the composite. From an economic perspective, the tooling cost for machining oil-palm based particleboard is estimated to be twice of the cost for machining wood-based particleboard. This study shows that the machining properties of oil-palm based particleboard will be a primary concern, if the board is to find widespread application as a potential substitute for wood-based particleboard.

  8. Friction and wear behavior of carbon fiber reinforced brake materials

    Institute of Scientific and Technical Information of China (English)

    Du-qing CHENG; Xue-tao WANG; Jian ZHU; Dong-bua QIU; Xiu-wei CHENG; Qing-feng GUAN

    2009-01-01

    A new composite brake material was fabri-cated with metallic powders, barium sulphate and modified phenolic resin as the matrix and carbon fiber as the reinforced material. The friction, wear and fade character-istics of this composite were determined using a D-MS friction material testing machine. The surface structure of carbon fiber reinforced friction materials was analyzed by scanning electronic microscopy (SEM). Glass fiber-reinforced and asbestos fiber-reinforced composites with the same matrix were also fabricated for comparison. The carbon fiber-reinforced friction materials (CFRFM) shows lower wear rate than those of glass fiber- and asbestos fiber-reinforced composites in the temperature range of 100℃-300℃. It is interesting that the frictional coefficient of the carbon fiber-reinforced friction materials increases as frictional temperature increases from 100℃ to 300℃, while the frictional coefficients of the other two composites decrease during the increasing temperatures. Based on the SEM observation, the wear mechanism of CFRFM at low temperatures included fiber thinning and pull-out. At high temperature, the phenolic matrix was degraded and more pull-out enhanced fiber was demonstrated. The properties of carbon fiber may be the main reason that the CFRFM possess excellent tribological performances.

  9. Friction and Wear Behaviors of Nano-Silicates in Water

    Institute of Scientific and Technical Information of China (English)

    Chen Boshui; Lou Fang; Fang Jianhua; Wang Jiu; Li Jia

    2009-01-01

    Nano-metric magnesium silicate and zinc silicate with particle size of about 50--70nm were prepared in water by the method of chemical deposition. The antiwear and friction reducing abilities of the nano-silicates, as well as their compos-ites with oleie acid tri-ethanolamine (OATEA), were evaluated on a four-ball friction tester. The topographies and tribochemical features of the worn surfaces were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS). Results show that nano-silicates alone provide poor antiwear and friction reducing abilities in water, but exhibits excellent synergism with OATEA in reducing friction and wear. The synergism in reducing friction and wear between naao-silicates and OATEA does exist almost regardless of particle sizes and species, and may be attributed, on one hand, to the formation of an adsorption film of OATEA, and, on the other hand, to the formation oftdbochemical species of silicon dioxide and iron oxides on the friction surfaces. Tribo-reactions and tribo-adsorptions of nano-silicates and OATEA would produce hereby an effective composite boondary lubrication film, which could efficiently enhance the anti-wear and friction-reducing abilities of water.

  10. NANOSCALE BOEHMITE FILLER FOR CORROSION AND WEAR RESISTANT POLYPHENYLENESULFIDE COATINGS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2003-06-26

    The authors evaluated the usefulness of nanoscale boehmite crystals as a filler for anti-wear and anti-corrosion polyphenylenesulfide (PPS) coatings exposed to a very harsh, 300 C corrosive geothermal environment. The boehmite fillers dispersed uniformly into the PPS coating, conferring two advanced properties: First, they reduced markedly the rate of blasting wear; second, they increased the PPS's glass transition temperature and thermal decomposition temperature. The wear rate of PPS surfaces was reduced three times when 5wt% boehmite was incorporated into the PPS. During exposure for 15 days at 300 C, the PPS underwent hydrothermal oxidation, leading to the substitution of sulfide linkages by the sulfite linkages. However, such molecular alteration did not significantly diminish the ability of the coating to protect carbon steel against corrosion. In fact, PPS coating filled with boehmite of {le} 5wt% adequately mitigated its corrosion in brine at 300 C. One concern in using this filler was that it absorbs brine. Thus, adding an excess amount of boehmite was detrimental to achieving the maximum protection afforded by the coatings.

  11. Influence of halogen irradiance on short- and long-term wear resistance of resin-based composite materials.

    LENUS (Irish Health Repository)

    Bhamra, Gurcharn S

    2009-02-01

    The Oregon Health Science University (OHSU) four-chamber oral wear simulator was used to examine the impact of halogen irradiance on the short- and long-term wear behavior of four-methacrylate resin-based composites (RBCs). The hypothesis proposed was that exacerbated wear would occur following the long-term wear of RBCs irradiated under non-optimized irradiance conditions.

  12. An individual tooth wear index and an analysis of factors correlated to incisal and occlusal wear in an adult Swedish population.

    Science.gov (United States)

    Ekfeldt, A; Hugoson, A; Bergendal, T; Helkimo, M

    1990-10-01

    The aim of the study was to introduce an individual tooth wear index and to use this index to investigate factors correlated to occlusal wear. The material consisted of 585 randomly selected dentate individuals from the community of Jönköping, Sweden, who in 1983 reached the age of 20, 30, 40, 50, 60, 70, or 80 years. The degree of incisal and occlusal wear was evaluated for each single tooth in accordance with criteria presented earlier. An individual tooth wear index, which made it possible to rank individuals in accordance with incisal and occlusal wear, was used as dependent variable to investigate factors related to incisal and occlusal wear. Of all factors analyzed, the following were found to correlate significantly with increased incisal and occlusal wear: number of existing teeth, age, sex, occurrence of bruxism, use of snuff, and saliva buffer capacity. Stepwise multiple regression analysis gave a total explanation factor of R2 = 0.41. It was also possible to distinguish well between groups of individuals with and without tooth wear by means of these factors.

  13. Backside Wear Analysis of Retrieved Acetabular Liners with a Press-Fit Locking Mechanism in Comparison to Wear Simulation In Vitro

    Directory of Open Access Journals (Sweden)

    Ana Laura Puente Reyna

    2016-01-01

    Full Text Available Backside wear due to micromotion and poor conformity between the liner and its titanium alloy shell may contribute to the high rates of retroacetabular osteolysis and consequent aseptic loosening. The purpose of our study was to understand the wear process on the backside of polyethylene liners from two acetabular cup systems, whose locking mechanism is based on a press-fit cone in combination with a rough titanium conical inner surface on the fixation area. A direct comparison between in vitro wear simulator tests (equivalent to 3 years of use and retrieved liners (average 13.1 months in situ was done in order to evaluate the backside wear characteristics and behavior of these systems. Similar wear scores between in vitro tested and retrieved liners were observed. The results showed that this locking mechanism did not significantly produce wear marks at the backside of the polyethylene liners due to micromotion. In all the analyzed liners, the most common wear modes observed were small scratches at the cranial fixation zone directly below the rough titanium inner surface of the shell. It was concluded that most of the wear marks were produced during the insertion and removal of the liner, rather than during its time in situ.

  14. A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2009-11-01

    The work summarized here comprises the concluding effort of a multi-year project, funded by the U.S. Department of Energy, Office of Vehicle Technologies. It supports the development of a better understanding of advanced diesel engine designs in which enhanced power density, energy efficiency, and emissions control place increasing demands upon the durability of engine materials. Many kinds of metallic alloys are used in engines depending on the operating stresses, temperatures, and chemical environments. Exhaust valves, for example, are subjected to high temperatures and repetitive surface contacts that place demands on durability and frictional characteristics of the materials. Valves must continue to seal the combustion chamber properly for thousands of hours of cyclic engine operation and under varying operating conditions. It was the focus of this effort to understand the wear processes in the valve-seat area and to develop a model for the surface deformation and wear of that important interface. An annotated bibliography is provided to illustrate efforts to understand valve wear and to investigate the factors of engine operation that affect its severity and physical manifestation. The project for which this modeling effort was the final task, involved construction of a high-temperature repetitive impact test system as well as basic tribology studies of the combined processes of mechanical wear plus oxidation at elevated temperatures. Several publications resulted from this work, and are cited in this report. The materials selected for the experimental work were high-performance alloys based on nickel and cobalt. In some cases, engine-tested exhaust valves were made available for wear analysis and to ensure that the modes of surface damage produced in experiments were simulative of service. New, production-grade exhaust valves were also used to prepare test specimens for experimental work along with the other alloy samples. Wear analysis of valves and seats

  15. Dry friction and wear characteristics of MoSi2 against ahoy steels

    Institute of Scientific and Technical Information of China (English)

    CHEN Ping; ZHANG Hou'an; TANG Guoning; LI Songwen

    2005-01-01

    The dry friction and wear characteristics of three kinds of friction couples under different loads, MoSi2/45 tempered steel, MoSi2/45 quenched steel, and MoSi2/CrWMn steel, were investigated by using a friction and wear tester. SEM and X-ray diffraction were employed to analyze the microphotograph of the worn surface and the phase of worn pieces in order to reveal the wear mechanisms of MoSi2 material. The results show that MoSi2/CrWMn steel friction pair has good dry friction and wear properties under the load of 80 N, where the friction coefficient is 0.255 and the wear rate of MoSi2 is only 14.72 mg.km-1. But under the load of 150 N, it is MoSi2/45 tempered steel friction pair that has good tribological properties,MoSi2 under low loads is brittle fracture. With the increase of load, the main wear mechanism of MoSi2 against 45 quenched steel or CrWMn steel is adhesive wear. However, the wear mechanism of MoSi2 against 45 tempered steel is changed from oxidation-fatigue wear to adhesive wear.

  16. Preparation, characterization and wear behavior of carbon coated magnesium alloy with electroless plating nickel interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Yan [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Academician Expert Office Workstation (Jiansheng Pan), Lin’an, Zhejiang Province (China); Feng, Kai, E-mail: fengkai@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Academician Expert Office Workstation (Jiansheng Pan), Lin’an, Zhejiang Province (China); Guo, Xingwu [National Engineering Research Center of Light Alloys Net Forming (LAF), School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhou, Zhifeng [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Dong, Jie [National Engineering Research Center of Light Alloys Net Forming (LAF), School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wu, Yixiong [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Academician Expert Office Workstation (Jiansheng Pan), Lin’an, Zhejiang Province (China)

    2015-02-01

    Highlights: • The carbon film with nickel interlayer (Ni + C coating) is deposited on GW83. • In Ni + C composite coating the carbon coating has good adhesion with the nickel interlayer. • The wear track of Ni + C coating is narrower compared to the bare one. • The wear resistance of GW83 is greatly improved by the Ni + C coating. - Abstract: Poor wear resistance of rare earth magnesium alloys has prevented them from wider application. In this study, composite coating (PVD carbon coating deposited on electroless plating nickel interlayer) is prepared to protect GW83 magnesium alloys against wear. The Ni + C composite coating has a dense microstructure, improved adhesion strength and hardness due to the effective support of Ni interlayer. The wear test result shows that the Ni + C composite coating can greatly prolong the wear life of the magnesium alloy. The wear track of the Ni + C coated magnesium alloy is obviously narrower and shows less abrasive particles as compared with the bare one. Abrasive wear is the wear mechanism of the coatings at the room temperature. In conclusion, the wear resistance of the GW83 magnesium alloy can be greatly improved by the Ni + C composite coating.

  17. COMPOSITION EFFECT ON DRY SLIDING WEAR BEHAVIORS OF Ti-B-N THIN FILMS

    Institute of Scientific and Technical Information of China (English)

    P. Sit; Y.H. Lu; H. Chen; Z.F. Zhou; Y.G. Shen; K.Y. Li

    2005-01-01

    Friction and sliding wear behaviour of Ti-B-N coatings against AISI440C steel ball and WC-6wt%Co ball were studied by using pin-on-disk tribometer along with microstructure characterization using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It is shown that the wear resistance of film depended on the wear mechanism. In the case of AISI440C steel, adhesive wear were pre-dominant and the wear rate increased sharply to a maximum when N content reach ~38at. %. This might be related to the change of film microstructure and phase configuration, so the least adhesive transfer of tribo-film was observed. If WC-6wt% Co ball was used, less deformation wear debris was observed, this was responsible for the rise of wear rate. Despite of different wear modes, friction coefficients in both cases were found to depend mainly on the formation and the amount of h-BN phase. Elemental analysis by energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) revealed that oxygen participated in the wear behavior by reacting with films to form the debris comprised of various types of Ti oxide including TiO, TiO2 and Ti2O3 ,which increased wear resistance.

  18. Effect of porosity on wear resistance of SiCp/Cu composites prepared by pressureless infiltration

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lin; QU Xuan-hui; DUAN Bo-hua; HE Xin-bo; QIN Ming-li

    2008-01-01

    The influence of porosity on the wear behavior of high volume fraction (61%) SiCp/Cu composite produced by pressureless infiltration was studied using a sliding, reciprocating and vibrating(SRV) machine. SiCp/Cu composites slid against hardened GCr15 bearing steel ball in the load range of 40-200 N. The results show that the wear rate increases with increasing porosity. The composite containing low porosity shows excellent wear resistance, which is attributed to the presence of mechanically mixed layer on the worn surface. In this case, the dominant wear mechanism is oxidative wear. Comparatively, the composite containing high porosity exhibits inferior wear resistance. Fracture and spalling of the particles are considered as the main causes of severe wear. Third body abrasion is the controlling wear mechanism. In addition, porosity has more important influence on wear rate at high load than at low load. This is associated with the fact that the fracture and spalling of particles is a process of crack initiation and propagation. At lower load, the pores beneath the worn surface can not propagate significantly, while the pores become unstable and easily propagate under high load, which results in a higher wear rate.

  19. Wear Characteristics of Ni-Based Hardfacing Alloy Deposited on Stainless Steel Substrate by Laser Cladding

    Science.gov (United States)

    Awasthi, Reena; Limaye, P. K.; Kumar, Santosh; Kushwaha, Ram P.; Viswanadham, C. S.; Srivastava, Dinesh; Soni, N. L.; Patel, R. J.; Dey, G. K.

    2015-03-01

    In this study, dry sliding wear characteristics of the Ni-based hardfacing alloy (Ni-Mo-Cr-Si) deposited on stainless steel SS316L substrate by laser cladding have been presented. Dry sliding wear behavior of the laser clad layer was evaluated against two different counter bodies, AISI 52100 chromium steel (~850 VHN) and tungsten carbide ball (~2200 VHN) to study both adhesive and abrasive wear characteristics, in comparison with the substrate SS316L using ball on plate reciprocating wear tester. The wear resistance was evaluated as a function of load and sliding speed for a constant sliding amplitude and sliding distance. The wear mechanisms were studied on the basis of wear surface morphology and microchemical analysis of the wear track using SEM-EDS. Laser clad layer of Ni-Mo-Cr-Si on SS316L exhibited much higher hardness (~700 VHN) than that of substrate SS316L (~200 VHN). The laser clad layer exhibited higher wear resistance as compared to SS316L substrate while sliding against both the counterparts. However, the improvement in the wear resistance of the clad layer as compared to the substrate was much higher while sliding against AISI 52100 chromium steel than that while sliding against WC, at the same contact stress intensity.

  20. Wear of sequentially enhanced 9-Mrad polyethylene in 10 million cycle knee simulation study.

    Science.gov (United States)

    Tsukamoto, Riichiro; Williams, Paul Allen; Shoji, Hiromu; Hirakawa, Kazuo; Yamamoto, Kengo; Tsukamoto, Mikiko; Clarke, Ian C

    2008-07-01

    Highly crosslinked polyethylene (HXPE) has been shown to be effective in reducing wear in total hip replacements. HXPE has not found widespread use in TKR, because the crosslinking inevitably leads to reductions in critical properties such as toughness and fatigue strength. Sequentially enhanced crosslinking (SXPE) have been suggested for improved wear resistance for tibial inserts with maintenance of mechanical properties and anticipated high oxidation resistance superior to conventional polyethylene (XLPE). We compared the wear of SXPE (9Mrad) to XLPE inserts (3Mrad) to 10 million cycles. Triathlon femoral condyles were identical in both. This is the first wear study of SXPE inserts. According to the power law relating irradiation dose to wear of XLPE inserts, wear of 9 Mrad inserts should be reduced by 70% compared to 3Mrad controls. The wear rates of the SXPE inserts were reduced by 86% at 10 million cycles duration, somewhat greater than predicted. The one prior investigation by the manufacturer reported a 79% wear reduction for SXPE compared to controls in a 5 million cycle simulator study in knee design and test parameters. There were important differences between the two studies. Nevertheless there clearly appeared to be a major benefit for sequentially enhanced polyethylene in tibial inserts. This combined wear reduction of 80-85% with improved oxidation resistance and retention of mechanical properties may prove beneficial for active patients who may otherwise risk high wear rates over many years of use.

  1. Comparison of three joint simulator wear debris isolation techniques: acid digestion, base digestion, and enzyme cleavage.

    Science.gov (United States)

    Niedzwiecki, S; Klapperich, C; Short, J; Jani, S; Ries, M; Pruitt, L

    2001-08-01

    Quantification of ultrahigh molecular weight polyethylene (UHMWPE) wear debris remains a challenging task in orthopedic device analysis. Currently, the weight loss method is the only accepted practice for quantifying the amount of wear generated from a PE component. This technique utilizes loaded soak controls and weight differences to account for polymeric material lost through wear mechanisms. This method enables the determination of the amount of wear in the orthopedic device, but it provides no information about debris particulate size distribution. In order to shed light on wear mechanisms, information about the wear debris and its size distribution is necessary. To date, particulate isolation has been performed using the base digestion technique. The method uses a strong base, ultracentrifugation, and filtration to digest serum constituents and to isolate PE debris from sera. It should be noted that particulate isolation methods provide valuable information about particulate size distribution and may elucidate the mechanisms of wear associated with polymeric orthopedic implants; however, these techniques do not yet provide a direct measure of the amount of wear. The aim of this study is to present alternative approaches to wear particle isolation for analysis of polymer wear in total joint replacements without recourse to ultracentrifugation. Three polymer wear debris isolation techniques (the base method, an acid treatment, and an enzymatic digestion technique) are compared for effectiveness in simulator studies. A requirement of each technique is that the wear particulate must be completely devoid of serum proteins in order to effectively image and count these particles. In all methods the isolation is performed through filtration and chemical treatment. Subsequently, the isolated polymer particles are imaged using scanning electron microscopy and quantified with digital image analysis. The results from this study clearly show that isolation can be

  2. Two-body wear of dental porcelain and substructure oxide ceramics.

    Science.gov (United States)

    Rosentritt, Martin; Preis, Verena; Behr, Michael; Hahnel, Sebastian; Handel, Gerhard; Kolbeck, Carola

    2012-06-01

    The aim of this in vitro study was to investigate the two-body wear of different ceramics. Two-body wear tests were performed in a chewing simulator with steatite and enamel antagonists, respectively. Specimens were loaded in a pin-on-block design with a vertical load of 50 N for 1.2 × 10(5) cycles; (f = 1.6 Hz; lateral movement, 1 mm; mouth opening: 2 mm). Human enamel was used as a reference. Three zirconia ceramics, three veneering porcelains, two glass-infiltrated and one lithium disilicate ceramic were investigated. Veneering and lithium disilicate ceramics were glazed before testing. Surface roughness Ra (SP6, Perthen-Feinprüf, G) and wear depth were determined using a 3D scanner (Laserscan 3D, Willytec, G). SEM (Quanta FEG 400, FEI, USA) pictures of the worn specimens and antagonists were made for evaluating wear performance. Veneering porcelain provided wear traces between 71.2 and 124.1 μm (enamel antagonist) and 117.4 and 274.1 μm (steatite). Wear of the steatite antagonists varied between 0.618 and 2.85 mm². No wear was found for zirconia and glass-infiltrated substructure ceramics. Also, no wear was found for the corresponding antagonists. Wear of specimens and antagonists was strongly material dependent. No visible wear was found on zirconia and glass-infiltrated ceramics. Porcelain and lithium disilicate ceramic showed a comparable or lower wear than the enamel reference. Antagonist wear was found to be lower when specimens were made of substructure oxide ceramics instead of veneering porcelain. From the point of wear testing, zirconia may be used for the fabrication of fixed dental prosthesis without veneering.

  3. Friction Wear Property of Brake Materials by Copper-based Powder Metallurgy With Various Brake Speeds

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-xiu; GAO Hong-xia; WEI Xiu-lan

    2004-01-01

    The experiment is conducted on MM-1000 friction test machine, which tests friction wear property of copper-based brake materials by powder metallurgy at different brake speeds. It shows that the coefficient of friction and wear volume are greatly influenced by brake speed. When the brake speed is 4000 r/min, which is a bit higher, the material still has a higher coefficient of friction with 0.47. When the brake speed is over 4000r/min, the coefficient of friction decreased rapidly. When the brake speed is 3000r/min, the material's wear is in its minimum. That is to say no matter how higher or lower the brake speed is the wear volume is bigger relatively. With the brake speed of the lower one it mainly refers to fatigue wear; while of higher one it mainly refers to abradant and oxidation wear.

  4. Recent developments in wear- and corrosion-resistant alloys for the oil industry

    Energy Technology Data Exchange (ETDEWEB)

    Raghu, D. [Deloro Stellite Inc., Goshen, IN (United States). Stellite Coatings Div.; Wu, J.B.C. [Stoody Deloro Stellite, Inc., St. Louis, MO (United States)

    1997-11-01

    Oil production and refining pose very severe wear and corrosion environments. Material designers are challenged with the need to design and develop materials that combine high corrosion resistance with good wear resistance. Coupled with that is the need for these materials to meet requirements such as fracture toughness and resistance to sulfide and chloride stress corrosion cracking. Often, increasing wear resistance compromises the corrosion and welding characteristics. This article covers a variety of material developments that address the problems of wear and corrosion, including alloy design fundamentals and pertinent wear properties and general corrosion resistance compared to traditional wear-resistant materials. Proven applications, with particular reference to petroleum and petrochemical areas, are discussed. Potential applications are also cited.

  5. Effects of tool flank wear on orthogonal cutting process of aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    YUAN Ping; KE Ying-lin

    2006-01-01

    The tool flank begins to wear out as soon as cutting process proceeds. Cutting parameters such as cutting forces and cutting temperature will vary with increasing degree of flank wear. In order to reveal the relationship between them, the theoretical situations of cutting process were analyzed considering the tool flank wear effect. The variation rules of cutting force, residual stress and temperature distributions along with the tool flank wear were analyzed comparing with the sharp tool tip. Through FEM simulation method, affections of the tool flank wear value VB on cutting forces, residual stress and temperature distributions were analyzed. A special result in this simulation is that the thrust force is more sensitive to tool flank wear, which can be used as a recognition method of tool condition monitoring. The FEM simulation analysis result agrees well with the experimental measuring data in public literatures and some experiments made also by the authors.

  6. Wear behaviour of electroless Ni-P coatings and optimization of process parameters using Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Prasanta [Department of Mechanical Engineering, Jadavpur University, Kolkata 700 032 (India)], E-mail: psahoo@vsnl.net

    2009-04-15

    This paper reports an experimental study of wear characteristics of electroless Ni-P coatings sliding against steel. Coating process parameters are optimized for minimum wear based on L{sub 27} Taguchi orthogonal design with four process parameters, viz., bath temperature, concentration of nickel source solution, concentration of reducing agent and annealing temperature. It is observed that annealing temperature and bath temperature have the most significant influence on wear characteristics of electroless Ni-P coating. The interaction of bath temperature and concentration of nickel source solution has some significant influence on wear. The surface morphology and composition of coatings are also studied with the help of scanning electron microscopy, energy dispersed X-ray analysis and X-ray diffraction analysis. The wear mechanism in EN coatings is found to be abrasive wear.

  7. Friction and wear behavior of electrodeposited amorphous Fe-Co-W alloy deposits

    Institute of Scientific and Technical Information of China (English)

    何凤姣; 雷惊天; 陆欣; 黄宇宁

    2004-01-01

    The microstructures, friction and wear behavior under dry sliding condition of electrodeposited amorphous Fe-Co-W alloy deposits heat treated at different temperatures were studied. A comparative study of hard chrome deposit under the same testing condition was also made. The experimental results show that the hardness and wear resistance of amorphous Fe-Co-W alloy deposits are improved with the increasing of heat treatment temperature, and reach the maximum value at 800 ℃, then decrease above 800 ℃. Under 40 N load, the wear resistance properties of the alloy deposits heat treated at 800 ℃ are superior to those of hard chrome deposit. The main wear mechanisms of amorphous Fe-Co-W alloy deposits heat treated below 600 ℃ are peeling, plastic and flowing deformation; when the deposits are heat treated above 700 ℃, they are plastic and flowing deformation. While the main wear mechanisms of hard chrome are abrasive wear, fatigue and peeling.

  8. Effects of WC particle size on the wear resistance of laser surface alloyed medium carbon steel

    Science.gov (United States)

    Tong, Xin; Li, Fu-hai; Kuang, Min; Ma, Wen-you; Chen, Xing-chi; Liu, Min

    2012-01-01

    The CO2 laser surface alloying technique was used to form wear resistance layers on medium carbon steel with a kind of spherical WC powder. The effects of WC particle size on the abrasive wear resistance were thoroughly investigated. The results indicate that the laser alloyed layer is characterized by dendritic primary phase and ledeburite microstructure, consisting of austenite, martensite and carbides of Fe3W3C, W2C and WC. The laser surface alloying with WC powder could improve the abrasive wear resistance of the medium carbon steel by over 63%. The factors such as the hardness, the amount and the distribution of WC particle determined the laser alloyed samples' wear resistance, and the laser alloyed sample with WC powder of 88-100 μm diameter presented the best wear resistance in this study. Furthermore, the wear resistance mechanisms of the laser alloyed layers were also explored.

  9. Wear resistance of a Cr3C2-NiCr detonation spray coating

    Science.gov (United States)

    Wang, Jun; Wang, Jun; Sun, Baode; Guo, Qixin; Nishio, Mitsuhiro; Ogawa, Hiroshi

    2002-06-01

    Coatings can be applied to surfaces to improve the surface characteristics over those of the bulk properties and are widely used in tribological applications either to reduce wear and/or to modify friction during contact. One of the foremost coating methods for combating wear is thermal spraying. To prolong the life of steel slab continuous casting rolls, Cr3C2-NiCr detonation spray coating was processed on the roll surface in a steelmaking plant in China. This article studies the mechanical properties and wear resistance of this coating. The abrasive and dry frictional wear testing were performed using a pin-on-disk tester. Experimental results show that the wear resistance of the coated samples, i.e., coating reduces the risk of seizure compared to uncoated samples, is much better than those of the uncoated steel at room and elevated temperatures with any load and sliding velocity. The coating wear mechanisms under different test conditions are discussed.

  10. Electrode Wear Prediction in Milling Electrical Discharge Machining Based on Radial Basis Function Neural Network

    Institute of Scientific and Technical Information of China (English)

    HUANG He; BAI Ji-cheng; LU Ze-sheng; GUO Yong-feng

    2009-01-01

    Milling electrical discharge machining (EDM) enables the machining of complex cavities using cylindrical or tubular electrodes. To ensure acceptable machining accuracy the process requires some methods of compensating for electrode wear. Due to the complexity and random nature of the process, existing methods of compensating for such wear usually involve off-line prediction. This paper discusses an innovative model of electrode wear prediction for milling EDM based upon a radial basis function (RBF) network. Data gained from an orthogonal experiment were used to provide training samples for the RBF network. The model established was used to forecast the electrode wear, making it possible to calculate the real-time tool wear in the milling EDM process and, to lay the foundations for dynamic compensation of the electrode wear on-line. This paper demonstrates that by using this model prediction errors can be controlled within 8%.

  11. Sliding wear behavior of high velocity arc sprayed Fe-Al coating

    Institute of Scientific and Technical Information of China (English)

    朱子新; 徐滨士; 马世宁; 张伟

    2003-01-01

    The friction and wear behavior of Fe-Al intermetallics based coating produced by high velocity arc spraying technique under dry sliding at room temperature were investigated using a ball-on-disc tribotester. The effect of sliding speed on friction coefficient and wear of the coating was studied. The worn surface of the coating was analyzed by scanning electron microscope (SEM) to explore sliding friction and wear mechanism. The results show that the variations of friction coefficient can be divided into three distinct steps during the trail. Both the friction coefficient and the wear of the coating increase with increased sliding speed due to accelerated crack propagation rate and lamellar structure with poor ductility of the coating. The coating surface is subjected to alternately tensile stress and compression stress during sliding wear process, and the predominant wear mechanism of the coatings appears to be brittle fracture and delamination.

  12. The Effect of Nodular Cast Iron Metal Matrix on the Wear Resistance

    Directory of Open Access Journals (Sweden)

    G. Gumienny

    2012-04-01

    Full Text Available The paper presents results of studies on the effect of the nodular cast iron metal matrix composition on the abrasive and adhesive wear resistance. Nodular cast iron with different metal matrix obtained in the rough state and ADI were tested. To research of abrasive and adhesive wear the pearlitic and bainitic cast iron with carbides and without this component were chosen. The influence of the carbides amount for cast iron wear resistance was examined. It was found, that the highest abrasive and adhesive wear resistance under conditions of dry friction has a nodular cast iron with carbides with upper and lower bainite. Carbides in bainitic and pearlitic cast iron significantly increase the wear resistance in these conditions. In terms of fluid friction the largest wear resistance had cast iron group with the highest hardness.

  13. Inhibiting wear particles-induced osteolysis with doxycycline

    Institute of Scientific and Technical Information of China (English)

    Chao ZHANG; Ting-ting TANG; Wei-ping REN; Xiao-ling ZHANG; Ke-rong DAI

    2007-01-01

    Aim: To study the effect of doxycycline (DOX) on osteoclastogenesis, mature osteoclast fate and function, wear particles-induced osteoeolysis, and to provide some foundation for treating aseptic loosening and osteolysis after joint arthroplasty. Methods: Osteoclasts were generated from mouse bone marrow monocytes with the receptor activator of NF-κB ligand and the macrophage colony stimulating factor. DOX at a concentration of 5, 10, 15, and 20 μg/mL was respectively added to the medium. Seven days later, the osteoclasts were determined through tartrate-resistant acid phosphatase (TRAP) staining. Mature osteoclasts were isolated from newborn rabbits and cultured for 3 d in 24-well plates or on bone slices. DOX at a concentration of 5, 10, 15, and 20 μg/mL was respectively added to the medium. After TRAP staining, the osteoclasts were counted, resorption on bone slices was quantified, and the area was calculated after to luidine blue and Mayer-hematoxylin staining. Polymethyl methacrylate (PMMA) or ultra-high molecular weight polyethylene (UHMWPE) particles were implanted on the calvariae of C57BL/J6 mice. DOX, at a dose of 2 and 10 mg-kg-1.d-1, was respectively given in traperitoneally for 7 d. Seven days later, the calvariae were removed and processed for pathological analysis. Results: DOX treatment effectively inhibited in vitro osteoclastogenesis, affected the fate of mature osteoclasts, and inhibited mature osteoclasts, causing bone resorption. In vivo data indicated that DOX strongly inhibited PMMA or UHMWPE-induced osteolysis and osteoclastogenesis. Conclusion: DOX can effectively inhibit osteoclastogenesis and affect mature osteoclast fate and suppress wear particles induced by osteoly-sis and osteoclastogenesis. DOX might be useful in the treatment or prevention of wear particles-induced osteolysis and aseptic loosening for its effect on osteoclast generation and mature osteoclast fate and function.

  14. Changes in the Eye Microbiota Associated with Contact Lens Wearing.

    Science.gov (United States)

    Shin, Hakdong; Price, Kenneth; Albert, Luong; Dodick, Jack; Park, Lisa; Dominguez-Bello, Maria Gloria

    2016-03-22

    Wearing contact lenses has been identified as a risk factor for the development of eye conditions such as giant papillary conjunctivitis and keratitis. We hypothesized that wearing contact lenses is associated with changes in the ocular microbiota. We compared the bacterial communities of the conjunctiva and skin under the eye from 58 subjects and analyzed samples from 20 subjects (9 lens wearers and 11 non-lens wearers) taken at 3 time points using a 16S rRNA gene-based sequencing technique (V4 region; Illumina MiSeq). We found that using anesthetic eye drops before sampling decreases the detected ocular microbiota diversity. Compared to those from non-lens wearers, dry conjunctival swabs from lens wearers had more variable and skin-like bacterial community structures (UniFrac;P value = 3.0). The results indicate that wearing contact lenses alters the microbial structure of the ocular conjunctiva, making it more similar to that of the skin microbiota. Further research is needed to determine whether the microbiome structure provides less protection from ocular infections. As in other body sites (i.e., the gut, skin, and mouth), the eye has a normal community of bacteria which are expected to confer resistance that provides protection from invaders. However, the eye microbiome has been largely neglected and is relevant to eye health and understanding eye diseases and to discovery of its functions. This report of a baseline study shows differences in the eye microbiome of contact lens wearers in relation to those of non-lens wearers and has the potential to help future studies explore novel insights into a possible role of the microbiome in the increased risk for eye infections in contact lens wearers. Copyright © 2016 Shin et al.

  15. Legislative Prohibitions on wearing a headscarf: Are they justified?

    Directory of Open Access Journals (Sweden)

    Fatima Osman

    2014-11-01

    Full Text Available A headscarf, a simple piece of cloth that covers the head, is a controversial garment that carries various connotations and meanings. While it may be accepted as just another item of clothing when worn by non-Muslim women, it is often the subject of much controversy when worn by Muslim women. In recent years the headscarf has been described as a symbol of Islam's oppression of women and simultaneously of terrorism. As the debate regarding the acceptability of the headscarf in the modern world continues, an increasing number of states have legislated to ban the wearing of the headscarf. This article critically examines the reasons underlying these bans and argues that these prohibitions are not justified. It does this by first analysing the place of the headscarf in Islam, its religious basis and its significance to Muslim women. It argues that the headscarf is more than just a mere religious symbol and that Muslim women wear the headscarf as a matter of religious obligation. The headscarf is considered to be an important religious practice protected by the right to freedom of religion. Thereafter the article examines legislative bans on the headscarf in France, Turkey and Switzerland in order to identify the most popular justifications advanced by states and courts for banning the headscarf. It critically evaluates the justifications for protecting secularism, preventing coercion, promoting equality and curbing religious extremism, and disputes that the reasons put forward by states and accepted by courts justify banning the headscarf. It thereafter explores how South African courts would respond to a headscarf ban and argues that schools and employers should accommodate the headscarf. While Muslim women may not have an absolute right to wear the headscarf, there has thus far been no justifiable reason for banning the headscarf.

  16. Analysis of Impact of Chosen Parameters on the Wear of Camshft

    Directory of Open Access Journals (Sweden)

    Burdzik R.

    2014-10-01

    Full Text Available The paper provides an analysis of the reasons for excessive wear of the camshafts system components based on models developed to describe the impact of selected material, technological and operational factors. The subject of the research was wear of camshaft cams studied in accordance with results of operation tests. Based on the said tests, the dependence of wear intensity of cams from their angular position was established. The respective calculation results enabled the function of cam fallibility to be determined.

  17. Fundamental studies on dynamic wear behavior of SBR rubber compounds modified by SBR rubber powder

    OpenAIRE

    Euchler, Eric; Heinrich, Gert; Michael, Hannes; Gehde, Michael; Stocek, Radek; Kratina, Ondrej; Kipscholl, Reinhold; Bunzel, Jörg-Michael; Saal, Wolfgang

    2016-01-01

    The aim of this study is focused on the experimental investigation of dynamic wear behavior of carbon black filled rubber compounds comprising pristine styrene butadiene rubber (SBR) together with incorporated SBR ground rubber (rubber powder). We also analyzed and described quantitatively the service conditions of some dynamically loaded rubber products, which are liable to wear (e.g. conveyor belts, tires). Beside the well-known standard test method to characterize wear resistance at steady...

  18. Targeted computational probabilistic corroboration of experimental knee wear simulator: the importance of accounting for variability.

    Science.gov (United States)

    Strickland, M A; Dressler, M R; Render, T; Browne, M; Taylor, M

    2011-04-01

    Experimental testing is widely used to predict wear of total knee replacement (TKR) devices. Computational models cannot replace this essential in vitro testing, but they do have complementary strengths and capabilities, which make in silico models a valuable support tool for experimental wear investigations. For effective exploitation, these two separate domains should be closely corroborated together; this requires extensive data-sharing and cross-checking at every stage of simulation and testing. However, isolated deterministic corroborations provide only a partial perspective; in vitro testing is inherently variable, and relatively small changes in the environmental and kinematic conditions at the articulating interface can account for considerable variation in the reported wear rates. Understanding these variations will be key to managing uncertainty in the tests, resulting in a 'cleaner' investigation environment for further refining current theories of wear. This study demonstrates the value of probabilistic in silico methods by describing a specific, targeted corroboration of the AMTI knee wear simulator, using rigid body dynamics software models. A deterministic model of the simulator under displacement-control was created for investigation. Firstly, a large sample of experimental data (N>100) was collated, and a probabilistic computational study (N>1000 trials) was used to compare the kinetic performance envelopes for in vitro and in silico models, to more fully corroborate the mechanical model. Secondly, corresponding theoretical wear-rate predictions were compared to the experimentally reported wear data, to assess the robustness of current wear theories to uncertainty (as distinct from the mechanical variability). The results reveal a good corroboration for the physical mechanics of the wear test rig; however they demonstrate that the distributions for wear are not currently well-predicted. The probabilistic domain is found to be far more sensitive at

  19. 120mm M830A1 Heat Round Wear Life Prediction

    Science.gov (United States)

    2009-04-01

    MABL CFD boundary layer cannon model, MACE thermal cannon model, MACE wear and erosion cannon model, and BL cannon coating-substrate wear and erosion...round history. RESULTS AND DISCUSSION 2 Computational 120mm M830A1 thermo-chemistry, interior-ballistics, CFD boundary layer, thermal, wear, and...Vm input matls. properties input g-w kinetic rate input microscopic matl void input (cracks,pits,interf, surf ) thermocouple input rounds-types

  20. Changes in food processing and occlusal dental wear during the early agricultural period in northwest Mexico.

    Science.gov (United States)

    Watson, James T

    2008-01-01

    Crown dimensions and occlusal surface wear rate and wear plane were evaluated using paired first and second mandibular molars from a sample of 84 Early Agricultural period (1600 B.C.-A.D. 200) skeletons from northwest Mexico. Although this period represents a major shift in subsistence strategies in the Sonoran Desert, from food-foraging to agriculture, archaeological and dental pathology studies have identified this period as one of relative dietary stability. It was therefore predicted that very little variation in occlusal wear would have occurred between the early phase (San Pedro: 1600-800 B.C.) and late phase (Cienega: 800 B.C.-A.D. 200). Comparison of crown diameters identified some phenotypic differences between sexes but not between archaeological phases. Molar occlusal surfaces were then divided into four quadrants, and wear scores recorded for each quadrant. Principle axis analysis was performed between total wear scores of paired, adjacent first and second mandibular molars to assess rate and occlusal wear plane over time. The analysis demonstrated that both wear rate and wear plane increased from the early to the late phase of the Early Agricultural period. These results indicate that although diet may have indeed remained stable during this period in the Sonoran Desert increases in the rate of wear and wear plane may reflect changes in food-processing techniques. It is suggested that more intensive processing of agricultural products during the Cienega phase simultaneously softened the diet to create more tooth-contact wear and introduced more grit to cause faster and more angled wear on the molar occlusal surfaces.

  1. The microstructural dependence of wear resistance in austenite containing plate steels

    Science.gov (United States)

    Wolfram, Preston Charles

    The purpose of this project was to examine the microstructural dependence of wear resistance of various plate steels, with interests in exploring the influence of retained austenite (RA). Materials resistant to abrasive wear are desirable in the industrial areas of agriculture, earth moving, excavation, mining, mineral processing, and transportation. Abrasive wear contributes to significant financial cost associated with wear to the industry. The motivation for the current study was to determine whether it would be beneficial from a wear resistance perspective to produce plate steels with increased amounts of retained austenite. This thesis investigates this motivation through a material matrix containing AR400F, Abrasive (0.21 wt pct C, 1.26 wt pct Mn, 0.21 wt pct Si, 0.15 wt pct Ni, 0.18 wt pct Mo), Armor (0.46 wt pct C, 0.54 wt pct Mn, 0.36 wt pct Si, 1.74 wt pct Ni, 0.31 wt pct Mo), 9260, 301SS, Hadfield, and SAE 4325 steels. The Abrasive, Armor and 9260 steels were heat treated using different methods such as quench and temper, isothermal bainitic hold, and quench and partitioning (Q&P). These heat treatments yielded various microstructures and the test matrix allowed for investigation of steels with similar hardness and varying levels of RA. The wear test methods used consisted of dry sand rubber wheel (DSRW), impeller-tumbler impact-abrasion (impeller), and Bond abrasion wear testing. DSRW and impeller wear resistance was found to increase with hardness and retained austenite levels at certain hardness levels. Some Q&P samples exhibited similar or less wear than the Hadfield steels in DSRW and impeller tests. Scanning electron microscopy investigation of wear surfaces revealed different wear mechanisms for the different wear test methods ranging from micro-plowing, to micro-cutting and to fragmentation.

  2. An Alternative Coding System Defining the Total and Severity of Wear

    Science.gov (United States)

    1996-04-01

    of fluid which may be retated to the severity of wear that has occurred in the sampled machine. A 20 to 30ml plastic bottle provides an adequate...University of Wales Swansea Abstract: A ferrous debris monitor is described which is capable of measuring the concentration of ferrous wear debris ...suspended in a lubricant and the severity of wear associated with particle size of this suspended debris . A coding system is proposed : PQ index(total

  3. Feasibility of wear compensation in micro EDM milling based on discharge counting and discharge population characterization

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; Tristo, G.

    2011-01-01

    This paper investigates the applicability of real time wear compensation in micro EDM milling based on discharge counting and discharge population characterization. Experiments were performed involving discharge counting and tool electrode wear measurement in a wide range of process parameters...... settings involving different current pulse shapes. A strong correlation is found between average discharge energy of the populations and wear and material removal per discharge. A validation was carried out showing the feasibility of the proposed approach....

  4. Wear Resistance of Friction Pair of Metal Composite/Copper under Electric Current

    Science.gov (United States)

    Aleutdinova, M. I.; Fadin, V. V.; Rubtsov, V. Ye; Aleutdinov, K. A.

    2016-11-01

    Sliding of metal composites against copper counterbody under severe conditions (i.e. at the contact current density higher 50 A/cm2 and at high roughness of counterbody) is carried out. It is shown that the composite of composition of Cu-30% of graphite shows low wear resistance in these conditions. Higher wear resistance is inherent in the composites containing lead and bearing steel. Impregnation of these composites by industrial oil hasn't led to noticeable increase in wear resistance.

  5. Orthogonal experiment investigation on wear resistance of MoSi2

    Institute of Scientific and Technical Information of China (English)

    CHEN Ping; TANG Guoning; ZHANG Hou'an; LIU Houcai

    2003-01-01

    The influence of lubricant conditions, wear loads, and counterparts on the friction and wear characteristics of an MoSi2 material was investigated by means of orthogonal analysis. Orthogonal experiment results show that the order of influencing degree of the factors is lubricant condition > load > counterpart. MoSi2 has excellent friction-wear comprehensive properties against higher-hardness counterparts on the higher load and 20 oil lubricant conditions.

  6. Dental wear quantity and direction in Chalcolithic and Medieval populations from southwest France.

    Science.gov (United States)

    Grimoud, Anne-Marie; Gibbon, Victoria E

    2017-01-01

    The aim of this study was to verify if dental wear changed due to the dietary shift between the Chalcolithic and Middle Ages from relatively hard and fibrous foods to soft cooked cereals. This was accomplished by comparing dental wear quantity and direction between people from two archaeological sites, Les Treilles during the Chalcolithic (mixed subsistence farmers) and Marsan from the Middle Ages (agriculturalists) in southwest France. The materials studied include 65 mandibles, 32 from Les Treilles and 33 from Marsan; 549 teeth were studied. The results show statistically significant difference in wear quantity and direction, the Chalcolithic population (Les Treilles) had the greatest levels of wear in a mainly oblique direction, with the anterior teeth heavily affected by wear. Comparatively, the Medieval sample (Marsan) had lesser levels of wear in a mainly horizontal direction, and the most heavily worn teeth were the molars and incisors. The quantity of wear seems to correlate well with changes in diet, the high level of wear on the anterior teeth in the Chalcolithic sample corresponds with the consumption of a mixed diet of fibrous and tough foods. At Marsan, the lower wear quantity was likely due to a diet of soft boiled cereals, requiring less mastication. However, wear direction appears dependent on several factors and may correlate with more mixed subsistence practices. This study demonstrates the need for additional research into the complex actions of mastication and its effect on dental wear, as well as standardised methodology for the examination of dental wear in archaeological samples. Copyright © 2016 Elsevier GmbH. All rights reserved.

  7. Increasing the wear resistance of ultra-high molecular weight polyethylene by adding solid lubricating fillers

    Energy Technology Data Exchange (ETDEWEB)

    Panin, S. V., E-mail: svp@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Kornienko, L. A.; Poltaranin, M. A.; Ivanova, L. R. [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Suan, T. Nguen [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2014-11-14

    In order to compare effectiveness of adding solid lubricating fillers for polymeric composites based on ultra-high molecular weight polyethylene (UHMWPE) with graphite, molybdenum disulfide and polytetrafluoroethylene, their tribotechnical characteristics under dry friction, boundary lubrication and abrasive wearing were investigated. The optimal weight fractions of fillers in terms of improving wear resistance have been determined. The supramolecular structure and topography of wear track surfaces of UHMWPE-based composites with different content of fillers have been studied.

  8. Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing

    Science.gov (United States)

    Bressan, José Divo; Schopf, Roberto Alexandre

    2011-05-01

    Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness only. However, there are others parameters which influences wear such as: fracture toughness, type of crystalline structure and the occurrence of hard precipitate in the metallic matrix and also its nature. In the present investigation, the wear mechanisms acting in tool steels were analyzed and, by normalized tests, wear resistance performance of nine different types of tool steels were evaluated by pin-on-disc testing. Conventional tool steels commonly used in tooling such as AISI H13 and AISI A2 were compared in relation to tool steels fabricated by sintering process such as Crucible CPM 3V, CPM 9V and M4 steels. Friction and wear testing were carried out in a pin-on-disc automated equipment which pin was tool steel and the counter-face was a abrasive disc of silicon carbide. Normal load of 5 N, sliding velocity of 0.45 m/s, total sliding distance of 3000 m and room temperature were employed. The wear rate was calculated by the Archard's equation and from the plotted graphs of pin cumulated volume loss versus sliding distance. Specimens were appropriately heat treated by quenching and three tempering cycles. Percentage of alloying elements, metallographic analyses of microstructure and Vickers microhardness of specimens were performed, analyzed and correlated with wear rate. The work is concluded by the presentation of a rank of tool steel wear rate, comparing the different tool steel abrasion wear resistance: the best tool steel wear resistance evaluated was the Crucible CPM 9V steel.

  9. An intelligent condition monitoring system for on-line classification of machine tool wear

    Energy Technology Data Exchange (ETDEWEB)

    Fu Pan; Hope, A.D.; Javed, M. [Systems Engineering Faculty, Southampton Institute (United Kingdom)

    1997-12-31

    The development of intelligent tool condition monitoring systems is a necessary requirement for successful automation of manufacturing processes. This presentation introduces a tool wear monitoring system for milling operations. The system utilizes power, force, acoustic emission and vibration sensors to monitor tool condition comprehensively. Features relevant to tool wear are drawn from time and frequency domain signals and a fuzzy pattern recognition technique is applied to combine the multisensor information and provide reliable classification results of tool wear states. (orig.) 10 refs.

  10. Analysis and Modelling of Electrode Wear in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Madsen, Anders; Pedersen, Kim; Friis, Kasper Storgaard

    2010-01-01

    A model describing electrode wear as a function of weld number, initial tip diameter, truncated cone angle, welding current and electrode force is proposed. Excellent agreement between the model and experimental results is achieved, showing that the model can describe the change in electrode tip ...... a central cavity is formed and one where smaller pits are formed randomly across the electrode face. The influence of these two types of surface pits on the nugget size are investigated using the FE code SORPAS, revealing ring welds and undersized weld nuggets....

  11. Study of wear analysis with {sup 18}F

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, N.; Nolen, J.A.; Blumenthal, D.J. [and others

    1995-08-01

    We are studying the possible use of low-energy radioactive beams for the wear analysis of various industrial components (e.g. engine parts and materials for orthopedic implants). Previous experiments with {sup 7}Be and {sup 22}Na studied components at implantation depths of several tens of micrometer. In a first series of experiments we implanted {sup 18}F ions into the surface layer, which opens the possibility to study wear in the critical first micrometer of various materials. {sup 18}F was produced via the p({sup 18}O, {sup 18}F)n reaction at E{sub 18}{sub O} = 110 MeV using a 1.22-mg/cm{sub 2} polypropylene foil as a hydrogen target. The {sup 18}F{sup 9+} ions were separated at {theta}=0{degrees} from the incident {sup 18}O{sup 8+} beam with the split-pole spectrograph. In order to allow for a rapid change of irradiation samples, the {sup 18}F ions penetrated a thin HAVAR foil and were implanted into the sample which was located outside the vacuum chamber behind the pressure window. The depth distribution of the {sup 18}F was tested by implantation into a series of 1.5-{mu} thick Mylar foils which were subsequently measured with respect to their {sup 18}F activity using a Si-surface barrier detector. The localization of the {sup 18}F ions was found to be better than 1.5 {mu}. The implantation depth could be varied in the range between 1.5 {mu} - 9 {mu} by choosing the appropriate distance between pressure window and implantation sample. The wear rate was determined by measuring the (decay-corrected) decrease of the activity remaining in the sample after it was polished with Emery paper. In a first experiment the wear of stainless steel could be measured by this technique with a sensitivity of better than 100 nm. A paper describing these results is under preparation.

  12. QUALITY EVALUATION OF THE TPP POWER GENERATING UNITS WEAR RECONDITIONING

    Directory of Open Access Journals (Sweden)

    E. M. Farhadzadeh

    2016-01-01

    Full Text Available Reconditioning of the power generating unit worn equipment and devices is conducted during the scheduled repair period. Quality of wear reconditioning is evaluated by technical state and repair work implementation. Quality of the repair work execution characterizes logistical activities of the power station and the repair services and is rated by a five-grade scale. There are three technical conditions: adequate, subject to reservations, falling short of the technical standard documentation requirements. In practical work these constraints give place to essential ambiguity of the decision. Further to regulating techniques by way of informational support, the authors propose conducting the wear-reconditioning quality evaluation (repair quality accordingly the technical-and-economic indexes pattern of change. The paper recommends applying similarly the fivegrade system in evaluating the power generating unit technical state and distinguishes intolerable, dissatisfactory, fair, good and model estimates. The study demonstrates the assessment criteria dependence on the character of reliability and economical efficiency of performance variation after the repair with increase or decrease of the technical-and-economic indexes in reference to their mean, minimum and maximum values before the repair. The cases ascribed to intolerable quality of the wear reconditioning are those with one or more technical-and-economic indexes that not only failed to improve their values but deteriorated, and at that they became the worst amongst observable values. The model quality estimate of the wear reconditioning is allotted under condition that the power unit technical-and-economic index valuations after the repair not merely improved but also exceeded the best among those under observation. The developed method and algorithm for quality evaluation of the scheduled repair implementation contribute to practical realization of the independent monitoring. This monitoring

  13. Titanium aluminide intermetallic alloys with improved wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun; Lin, Hua-Tay; Blau, Peter J.; Sikka, Vinod K.

    2014-07-08

    The invention is directed to a method for producing a titanium aluminide intermetallic alloy composition having an improved wear resistance, the method comprising heating a titanium aluminide intermetallic alloy material in an oxygen-containing environment at a temperature and for a time sufficient to produce a top oxide layer and underlying oxygen-diffused layer, followed by removal of the top oxide layer such that the oxygen-diffused layer is exposed. The invention is also directed to the resulting oxygen-diffused titanium aluminide intermetallic alloy, as well as mechanical components or devices containing the improved alloy composition.

  14. Wear Debris Analysis of Grease Lubricated Ball Bearings.

    Science.gov (United States)

    1982-04-12

    fluid and debris were placed in a glass bottle and sealed with a plastic cap using a teflon sealing disk. The grease and cleaning fluid were...manner. 1. Ten 3m-diameter glass beads were placed in a 1/2 ounce bottle . The use of these glass beads aided the agitation process of the grease...AD-A19’ 470 NAVAL AIR ENGINEERING CENTER LAKEHURST NJ SUPPORT EGU -ETC F/B 11/9 WEAR DEBRIS ANALYSIS OF GREASE LUBRICATED BALL BEARINGS(U

  15. Tool electrode wear in electrical discharge of small diameter holes

    Directory of Open Access Journals (Sweden)

    Slătineanu Laurenţiu

    2017-01-01

    Full Text Available In the paper, the problem of obtaining small diameter holes in workpieces made of high speed steel by electrical discharge machining was formulated. A fulfil factorial experiment was designed and materialized, taking into consideration the tool electrode diameter, pulse on time and pulse off time as independent variables. The tool electrode wear was evaluated by means of the decrease of tool electrode mass and length. On the base of experimental results, power type empirical mathematical models were determined. One noticed the higher influence exerted by the too electrode diameter, whose increase determine the decrease of the tool electrode.

  16. Accelerated electrospark deposition and the wear behavior of coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, P.Z.; Pan, G.S.; Zhou, Y.; Qu, J.X.; Shao, H.S. [China Univ. of Mining and Technology, Beijing (China). Beijing Graduate School

    1997-12-01

    Electrospark deposition (ESD) is a coating process that is featured by low heat input to the substrate. Low coating efficiency and other limitations influence its wider application. The present paper introduces newly designed ESD equipment, by which a higher coating rate can be reached. The relationship among coating thickness, surface roughness, and process parameters such as pulse energy, pulse frequency, and deposition time are presented. Electrospark deposition coating by the new equipment on AISI 1045 steel (with WC-8% Co as electrode) increases the wear resistance by 5 to 8 times. The micromechanism is investigated by scanning electron microscopy observation.

  17. Astronaut Russell Schweickart wears EMU and PLSS for countdown test

    Science.gov (United States)

    1969-01-01

    Astronaut Russell L. Schweickart, lunar module pilot of the Apollo 9 prime crew, wears the extravehicular mobility unit (EMU) which he will use during his scheduled Apollo 9 extravehicular activity. In addition to the space suit and bubble helmet, the EMU also includes a portable life support system (PLSS) back pack, an Oxygen Purge System (seen atop the PLSS), and a Remote Control Unit on his chest. When this photograph was taken, Schweickart was suited up to participate in an Apollo 9 Countdown Demonstration Test.

  18. Preparation of Wear Resistant Materials by Melting and Diffusion Process

    Institute of Scientific and Technical Information of China (English)

    YU Shihao; WEI Xueping; ZENG Hui

    2012-01-01

    A wear-resistant material reinforced with VCp was manufactured by the in-mold melting process,in which the high-vanadium alloy-rods were melted by high temperature liquid steel and elements diffused into the liquid.Microstructure of the material was examined by OM,SEM,and XRD,and alloy elements in the diffusion layer were studied by EDS,and the hardness of the material was tested by HRS.The experimental results show that the material gradually changes hardness,which is due to the uniformly existents of carbide particles on martensite matrix and the gradient distribution of vanadium and carbide.

  19. Analysis and Modelling of Electrode Wear in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Madsen, Anders; Pedersen, Kim; Friis, Kasper Storgaard

    2010-01-01

    diameter with increasing weld number at different weld settings. Furthermore a method for measuring the worn tip diameter in a fast and robust manner is developed. The method relies on a well-known technique for capturing the electrode tip area by the use of carbon imprints and a new developed image......-processing program written in MatLab. Very fine agreement between the present experimental results and previously published wear data is achieved. Finally the pitted areas on the electrode tip are analyzed using MatLab and an optical 3D surface measurement device. Two types of pitting are characterized. One where...

  20. Standard Test Method for Abrasive Wear Resistance of Cemented

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the determination of abrasive wear resistance of cemented carbides. 1.2 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units are in parentheses and may be approximate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  1. Anti-wear properties of the molluscan shell Scapharca subcrenata: Influence of surface morphology, structure and organic material on the elementary wear process

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Limei, E-mail: lmtian@jlu.edu.cn [Key Laboratory of Bionic Engineering (Jilin University), Ministry of Education, Changchun 130022 (China); Tian, Ximei, E-mail: txm@jlu.edu.cn [Secretariat of the International Society of Bionic Engineering, Jilin University, Changchun 130012 (China); Wang, Yinci [Key Laboratory of Bionic Engineering (Jilin University), Ministry of Education, Changchun 130022 (China); Hu, Guangliang, E-mail: guoliang_huu@163.com [School of Automobile and Traffic Engineering, Jiangsu University, Zhenjiang 212013 (China); Ren, Luquan, E-mail: lqren@jlu.edu.cn [Key Laboratory of Bionic Engineering (Jilin University), Ministry of Education, Changchun 130022 (China)

    2014-09-01

    As a typical natural biological mineralisation material, molluscan shells have excellent wear-resistance properties that result from the interactions amongst biological coupling elements such as morphology, structure and material. The in-depth study of the wear-resistance performance of shells and the contribution made by each coupling element may help to promote the development of new bionic wear-resistant devices. The objective of this study was to investigate the influence of surface morphology (rib distribution on the shell), structure (rib coupled with nodules) and material (organic matter) on the anti-wear performance of the molluscan Scapharca subcrenata shell. The effect and contribution of each of these biological coupling elements were systematically investigated using the comparative experiment method. All three were found to exert significant effects on the shell's wear-resistance ability, and their individual contributions to that ability were revealed. Organic material can be classified as the principal coupling element, rib morphology as the secondary coupling element and the combined rib-nodule structure as the general coupling element. - Highlights: • We found that the S. subcrenata shell has an anti-wear ability. • This is related to the morphology, structure and material of the shell surface. • Organic material is the principal coupling element in its anti-wear ability. • Rib morphology could be considered the secondary coupling element. • The coupled structure could be regarded as the general coupling element.

  2. A review on nozzle wear in abrasive water jet machining application

    Science.gov (United States)

    Syazwani, H.; Mebrahitom, G.; Azmir, A.

    2016-02-01

    This paper discusses a review on nozzle wear in abrasive water jet machining application. Wear of the nozzle becomes a major problem since it may affect the water jet machining performance. Design, materials, and life of the nozzle give significance effect to the nozzle wear. There are various parameters that may influence the wear rate of the nozzle such as nozzle length, nozzle inlet angle, nozzle diameter, orifice diameter, abrasive flow rate and water pressure. The wear rate of the nozzle can be minimized by controlling these parameters. The mechanism of wear in the nozzle is similar to other traditional machining processes which uses a cutting tool. The high pressure of the water and hard abrasive particles may erode the nozzle wall. A new nozzle using a tungsten carbide-based material has been developed to reduce the wear rate and improve the nozzle life. Apart from that, prevention of the nozzle wear has been achieved using porous lubricated nozzle. This paper presents a comprehensive review about the wear of abrasive water jet nozzle.

  3. Method for the location of primary wear scars from retrieved metal on metal hip replacements.

    Science.gov (United States)

    Govind, Garima; Henckel, Johann; Hothi, Harry; Sabah, Shiraz; Skinner, John; Hart, Alister

    2015-07-30

    Retrieved metal-on-metal acetabular cups are valuable resources in investigating the wear behaviour of failed hip implants, but adequate methods to do so are lacking. To further contribute to addressing this issue, we developed a method to detect the in vivo location of the primary wear scar of an explanted cup. We proposed a new method in which thirteen patients with failed metal hip resurfacings were recruited, and their acetabular components retrieved. A 3D wear map was generated and the precise location of the primary wear scar in each cup was identified using a coordinate measuring machine. This wear scar location was noted in relation to the features on the acetabular cup. Having identified the location of the wear scar, this 3D positional map was co-registered to the implant on the patient's pelvic 3D CT scan. Using our proposed technique, we were able to demonstrate that the in vivo position of the primary wear scar in explanted metal acetabular cups can be variable. This method has utilised existing techniques to better understand the three-dimensional properties of wear behaviour, and may be a method which can be used in further studies to investigate variables that affect the position of the primary wear scar.

  4. Influence of Cycle Temperature on the Wear Resistance of Vermicular Iron Derivatized with Bionic Surfaces

    Science.gov (United States)

    Sui, Qi; Zhang, Peng; Zhou, Hong; Liu, Yan; Ren, Luquan

    2016-11-01

    Depending on their applications, such as in brake discs, camshafts, etc., the wear behavior of vermicular iron is influenced by the thermal cycling regime. The failure of a working part during its service life is a consequence of both thermal fatigue and wear. Previously, the wear and thermal fatigue resistance properties of vermicular iron were separately investigated by researchers, rather than a study combining these two factors. In the present work, the effect of cycle temperature on the wear resistance of specimens with bionic units processed by laser has been investigated experimentally. The wear behavior pre- and post-thermal cycling has also been investigated, and the influence of different cycle temperatures on the wear resistance is discussed. The results indicate that the thermal cycling regime brought about negative influences with varying degrees, on the material properties, such as the microstructures, micro-hardness, cracks, and oxidation resistance properties. All these factors synergistically reduced the wear resistance of vermicular iron. In particular, the negative influence apparently increased with an increase in cycle temperature. Nevertheless, the post-thermal-cycle wear resistance of the specimens with bionic units was superior to those without bionic units. Hence, the laser bionic process is an effective way to improve the performance of vermicular iron in combined thermal cycling and wear service conditions.

  5. The effect of Tricresyl-Phosphate (TCP) as an additive on wear of Iron (Fe)

    Science.gov (United States)

    Ghose, Hiren M.; Ferrante, John; Honecy, Frank C.

    1987-01-01

    The effect of tricresyl phosphate (TCP) as an antiwear additive in lubricant trimethyol propane triheptanoate (TMPTH) was investigated. The objective was to examine step loading wear by use of surface analysis, wetting, and chemical bonding changes in the lubricant. The investigation consisted of steploading wear studies by a pin or disk tribometer, the effects on wear related to wetting by contact angle and surface tension measurements of various liquid systems, the chemical bonding changes between lubricant and TCP chromatographic analysis, and by determining the reaction between the TCP and metal surfaces through wear scar analysis by Auger emission spectroscopy (AES). The steploading curve for the base fluid alone shows rapid increase of wear rate with load. The steploading curve for the base fluid in presence of 4.25 percent by volume TCP under dry air purge has shown a great reduction of wear rate with all loads studied. It has also been found that the addition of 4.25 percent by volume TCP plus 0.33 percent by volume water to the base lubricant under N2 purge also greatly reduces the wear rate with all loads studied. AES surface analysis reveals a phosphate type wear resistant film, which greatly increases load-bearing capacity, formed on the iron disk. Preliminary chromatographic studies suggest that this film forms either because of ester oxidation or TCP degradation. Wetting studies show direct correlation between the spreading coefficient and the wear rate.

  6. Tribochemistry of Carbon Films in Oxygen and Humid Environments: Oxidative Wear and Galvanic Corrosion.

    Science.gov (United States)

    Alazizi, Ala; Draskovics, Andrew; Ramirez, Giovanni; Erdemir, Ali; Kim, Seong H

    2016-03-01

    The effects of oxidation on wear of carbon/steel tribological interfaces were studied. When mechanical wear was small, the oxidation behavior of hydrogenated diamond-like carbon (H-DLC) and stainless steel (SS) sliding interface varied depending on the nature of the oxidizing environment. In dry air or oxygen, both H-DLC and SS wore readily. The wear debris of SS did not form iron oxide in dry air and oxygen. In humid nitrogen, however, the wear of H-DLC diminished with increasing humidity, and the SS surface showed mild wear and iron oxide debris accumulated around the sliding contact region. These results revealed that different tribochemical reactions occur in dry oxygen and humid environments. In the absence of water, oxygen oxidizes the H-DLC surface, making it susceptible to wear, creating debris, and inducing wear on both H-DLC and SS. In contrast, adsorbed water molecules at less than 40% RH act as a molecular lubricant of the oxidized DLC surface, while multiwater layers adsorbed at near-saturation act as electrolyte inducing electrochemical galvanic corrosion reactions on the SS surface. When hydrogen-free amorphous carbon (a-C) was used in tribo-tests, severe wear of the SS surface occurs, in addition to the tribochemical wear observed for H-DLC, due to the high hardness of the a-C film.

  7. Factors related to seatbelt-wearing among rear-seat passengers in Malaysia.

    Science.gov (United States)

    Ng, Choy Peng; Law, Teik Hua; Wong, Shaw Voon; Kulanthayan, S

    2013-01-01

    The benefit of wearing a rear seatbelt in reducing the risk of motor vehicle crash-related fatalities and injuries has been well documented in previous studies. Wearing a seatbelt not only reduces the risk of injury to rear-seat passengers, but also reduces the risk of injury to front-seat occupant who could be crushed by unbelted rear-seat passengers in a motor vehicle crash. Despite the benefits of wearing a rear seatbelt, its rate of use in Malaysia is generally low. The objective of this study was to identify factors that are associated with the wearing of a seatbelt among rear-seat passengers in Malaysia. Multinomial logistic regression analysis of the results of a questionnaire survey of 1651 rear-seat passengers revealed that rear-seat passengers who were younger, male, single and less educated and who had a perception of a low level of legislation enforcement, a lower risk-aversion and less driving experience (only for passengers who are also drivers) were less likely to wear a rear seatbelt. There was also a significant positive correlation between driver seatbelt and rear seatbelt-wearing behaviour. This implies that, in regards to seatbelt-wearing behaviour, drivers are more likely to adopt the same seatbelt-wearing behaviour when travelling as rear-seat passengers as they do when driving. These findings are crucial to the development of new interventions to increase the compliance rate of wearing a rear seatbelt.

  8. Wear and Grip Loss Evaluation of High Chromium Welding Deposits Applied on Sugar Cane Rolls1

    OpenAIRE

    Diaz Millan, Sebastian; Rugbeño S.A.S; Aguilar Castro, Yesid; Escuela de Ingeniería de Materiales, Universidad del Valle, Cali, Colombia; Casanova García, Gonzalo Fernando; Escuela de Ingeniería Mecánica,Universidad del Valle, Cali, Colombia

    2015-01-01

    Wear on sugar cane rolls is an expensive maintenance problem for the sugar cane industry. Wear produces loss of sucrose extraction and loss of grip of the roll on the bagasse. This paper presents the evaluation of wear and loss of grip of hypoeutectic and hypereutectic high chromium welding deposits applied on ASTM A-36 steel and gray cast iron. A modified ASTM G-65 standard test was used. Wear was produced by the abrasive action of wet bagasse with three levels of mineral extraneous matter. ...

  9. Effect of Deformation Mode on the Wear Behavior of NiTi Shape Memory Alloys

    Science.gov (United States)

    Yan, Lina; Liu, Yong

    2016-06-01

    Owing to good biocompatibility, good fatigue resistance, and excellent superelasticity, various types of bio-medical devices based on NiTi shape memory alloy (SMA) have been developed. Due to the complexity in deformation mode in service, for example NiTi implants, accurate assessment/prediction of the surface wear process is difficult. This study aims at providing a further insight into the effect of deformation mode on the wear behavior of NiTi SMA. In the present study, two types of wear testing modes were used, namely sliding wear mode and reciprocating wear mode, to investigate the effect of deformation mode on the wear behavior of NiTi SMA in both martensitic and austenitic states. It was found that, when in martensitic state and under high applied loads, sliding wear mode resulted in more surface damage as compared to that under reciprocating wear mode. When in austenitic state, although similar trends in the coefficient of friction were observed, the coefficient of friction and surface damage in general is less under reciprocating mode than under sliding mode. These observations were further discussed in terms of different deformation mechanisms involved in the wear tests, in particular, the reversibility of martensite variant reorientation and stress-induced phase transformation, respectively.

  10. Wear of nanofilled dental composites in a newly-developed in vitro testing device

    Science.gov (United States)

    Lawson, Nathaniel C.

    Purpose. In vivo wear of dental composites can lead to loss of individual tooth function and the need to replace a composite restoration. To evaluate the wear performance of new and existing dental composites, we developed a novel system for measuring in vitro wear and we used this system to analyze the mechanisms of wear of nanofilled composite materials. Methods. A modified wear testing device was designed based on the Alabama wear testing machine. The new device consists of: (1) an antagonist which is lowered to and raised from the composite specimen by weight loading, (2) a motorized stage to cause the antagonist to slide 2mm on the composite surface, and (3) pumps for applying lubricant to the specimens. Various testing parameters of the device were examined before testing, including the impulse force, the third-body medium, the lubricant and antagonist. The parameters chosen for this study were 20N at 1Hz with a 33% glycerine lubricant and stainless steel antagonist. Three nano-composites were fabricated with a BisGMA polymer matrix and 40nm SiO2 filler particles at three filler loads (25%, 50% and 65%). The mechanical properties of the composites were measured. The materials were then tested in the modified wear testing device under impact wear, sliding wear and a combination of impact and sliding wear. The worn surfaces were then analyzed with a non-contact profilometer and SEM. Results. The volumetric wear data indicated that increasing filler content beyond 25% decreased the wear resistance of the composites. Increasing filler content increased hardness and decreased toughness. SEM evaluation of the worn specimens indicated that the 25% filled materials failed by fatigue and the 50% and 65% filled materials failed by abrasive wear. Impact wear produced fretting in this device and sliding wear is more aggressive than impact wear. Conclusion. Based on the results of this study and previous studies on this topic, manufacturers are recommended to use a filler

  11. Wear mechanisms of dental composite restorative materials by two different in-vitro methods

    Directory of Open Access Journals (Sweden)

    Juliana Antonino de Souza

    2013-04-01

    Full Text Available In this work two very simple apparatuses, namely the ball crater (or ball-on-plate and the linear reciprocating (or pin-on-plate tests, were used in order to investigate the wear mechanisms of TPH Spectrum® and Resilab Master® dental composite resins. Loads in the range of 100 g to 1 kg and a total number of up to 24000 cycles were employed. During some of these tests, aqueous aluminum oxide suspensions were used as abrasive agent either diluted or not in distilled water. In case of the ball-on-plate test wear is dominated by abrasive and/or adhesive mechanisms, and is characterized by scratches which are composed of wear defects comprising particle detachment, wear of the polymer matrix and ceramic particle abrasion. However, the relative contributions of the two wear mechanisms could not be determined separately. In case of the pin-on-plate test wear is governed by the fatigue mechanism, although abrasive and adhesive wear mechanism are also present. After a certain number of cycles fatigue wear dominates the wear behavior and results in severe material loss. This mechanism seems to be more important in case of more brittle materials and when higher loads are employed. Qualitative analysis of the results suggests that the combination of these two very simple methods under appropriate conditions can yield sound results which may be representative of a number of clinical situations.

  12. Wear mechanisms of dental composite restorative materials by two different in-vitro methods

    Directory of Open Access Journals (Sweden)

    Juliana Antonino de Souza

    2012-01-01

    Full Text Available In this work two very simple apparatuses, namely the ball crater (or ball-on-plate and the linear reciprocating (or pin-on-plate tests, were used in order to investigate the wear mechanisms of TPH Spectrum® and Resilab Master® dental composite resins. Loads in the range of 100 g to 1 kg and a total number of up to 24000 cycles were employed. During some of these tests, aqueous aluminum oxide suspensions were used as abrasive agent either diluted or not in distilled water. In case of the ball-on-plate test wear is dominated by abrasive and/or adhesive mechanisms, and is characterized by scratches which are composed of wear defects comprising particle detachment, wear of the polymer matrix and ceramic particle abrasion. However, the relative contributions of the two wear mechanisms could not be determined separately. In case of the pin-on-plate test wear is governed by the fatigue mechanism, although abrasive and adhesive wear mechanism are also present. After a certain number of cycles fatigue wear dominates the wear behavior and results in severe material loss. This mechanism seems to be more important in case of more brittle materials and when higher loads are employed. Qualitative analysis of the results suggests that the combination of these two very simple methods under appropriate conditions can yield sound results which may be representative of a number of clinical situations.

  13. Optimization of image capturing method of wear particles for condition diagnosis of machine parts

    Institute of Scientific and Technical Information of China (English)

    Yon-Sang CHO; Heung-Sik PARK

    2009-01-01

    Wear particles are inevitably occurred from moving parts, such as a piston-cylinder made from steel or hybrid materials. And a durability of these parts must be evaluated. The wear particle analysis has been known as a very effective method to foreknow and decide a moving situation and a damage of machine parts by using the digital computer image processing. But it is not laid down to calculate shape parameters of wear particle and wear volume. In order to apply image processing method in a durability evaluation of machine parts, it needs to verify the reliability of the calculated data by the image processing and to lay down the number of images and the amount of wear particles in one image. In this work, the lubricated friction experiment was carried out in order to establish the optimum image capture with the 1045 specimen under experiment condition. The wear particle data were calculated differently according to the number of image and the amount of wear particle in one image. The results show that capturing conditions need to he more than 140 wear particles in one image and over 40 images for the reliable data. Thus, the capturing method of wear particles images was optimized for condition diagnosis of machine moving parts.

  14. Microstructural features controlling the dry sliding wear response of some bearing alloys

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, B.K.; Yegneswaran, A.H. [Regional Res. Lab. (CSIR), Habibganj Naka (India); Patwardhan, A.K. [Roorkee Univ. (India). Dept. of Metallurgical Engineering

    1997-10-01

    This investigation examines the influence of microstructural features on the dry sliding wear characteristics of some plain bearing alloys. Three different alloys were selected for the study: a leaded-tin bronze, an Al bronze and a Zn-based alloy processed under identical conditions. The wear characteristics of the alloys are explained in terms of the load bearing capability, microcracking tendency, thermal stability and lubricating properties of their microconstituents and the sliding conditions. Wear surfaces, subsurface regions and debris are examined to understand the material removal mechanisms during the process of wear. (orig.) 37 refs.

  15. A comparative wear study on Al-Li and Al-Li/SiC composite

    Science.gov (United States)

    Okumus, S. Cem; Karslioglu, Ramazan; Akbulut, Hatem

    2013-12-01

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al2O3 ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms-1 and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  16. Roll wear on finishing trains of ASP1700 hot strip mills

    Institute of Scientific and Technical Information of China (English)

    Zhimin Xi; Anrui He; Quan Yang; Xiaoxia Lai; Haodong Huang; Lin Zhao

    2004-01-01

    A great deal of research and practical production indicated that a perfect shape control system needs a precise prediction model of roll wear. According to the practical wear curve of work roll in Angang ASP1700 hot strip mill, which was measured by a roll-profilemeter, the model of wear curve caused by one single strip was established. The prediction of work-roll wear was achieved by combining Fortran language and practical technology parameters. The calculated results agreed well with the measured.

  17. Impact Fretting Wear Behavior of Alloy 690 Tubes in Dry and Deionized Water Conditions

    Science.gov (United States)

    Cai, Zhen-Bing; Peng, Jin-Fang; Qian, Hao; Tang, Li-Chen; Zhu, Min-Hao

    2017-07-01

    The impact fretting wear has largely occurred at nuclear power device induced by the flow-induced vibration, and it will take potential hazards to the service of the equipment. However, the present study focuses on the tangential fretting wear of alloy 690 tubes. Research on impact fretting wear of alloy 690 tubes is limited and the related research is imminent. Therefore, impact fretting wear behavior of alloy 690 tubes against 304 stainless steels is investigated. Deionized water is used to simulate the flow environment of the equipment, and the dry environment is used for comparison. Varied analytical techniques are employed to characterize the wear and tribochemical behavior during impact fretting wear. Characterization results indicate that cracks occur at high impact load in both water and dry equipment; however, the water as a medium can significantly delay the cracking time. The crack propagation behavior shows a jagged shape in the water, but crack extended disorderly in dry equipment because the water changed the stress distribution and retarded the friction heat during the wear process. The SEM and XPS analysis shows that the main failure mechanisms of the tube under impact fretting are fatigue wear and friction oxidation. The effect of medium(water) on fretting wear is revealed, which plays a potential and promising role in the service of nuclear power device and other flow equipments.

  18. Wear and Corrosion of Cast Al Alloy Piston with and without Brake Oil

    OpenAIRE

    Olawale Olarewaju Ajibola; Daniel Toyin Oloruntoba

    2015-01-01

    The effects of wear and corrosion of cast AA6061 aluminium alloy were studied with and without brake fluid using a wear jig while the corrosion rate was determined in brake fluid for 70 days under two experimental set-ups. The tests, yielded 0.00000123 g/mm2/min highest wear rate at 147000 wear cycles and 0.0334 mg/mm2/yr as the highest corrosion rate within the early 39th day of immersion in oil, the values being considered comparatively lower than those obtained for Al alloy in most common ...

  19. Detailed study of oxidation/wear mechanism in lox turbopump bearings

    Science.gov (United States)

    Chase, T. J.; McCarty, J. P.

    1993-12-01

    Wear of 440C angular contact ball bearings of the phase 2 high pressure oxygen turbopump (HPOTP) of the space shuttle main engine (SSME) has been studied by means of various advanced nondestructive techniques (NDT) and modeled with reference to all known material, design, and operation variables. Three modes dominating the wear scenario were found to be the adhesive/sheer peeling (ASP), oxidation, and abrasion. Bearing wear was modeled in terms of the three modes. Lacking a comprehensive theory of rolling contact wear to date, each mode is modeled after well-established theories of sliding wear, while sliding velocity and distance are related to microsliding in ball-to-ring contacts. Microsliding, stress, temperature, and other contact variables are evaluated with analytical software packages of SHABERTH(TM)/SINDA(TM) and ADORE(TM). Empirical constants for the models are derived from NIST experiments by applying the models to the NIST wear data. The bearing wear model so established precisely predicts quite well the average ball wear rate for the HPOTP bearings. The wear rate has been statistically determined for the entire population of flight and development bearings based on Rocketdyne records to date. Numerous illustrations are given.

  20. Wear of Polished Steel Surfaces in Dry Friction Linear Contact on Polimer Composites with Glass Fibres

    Directory of Open Access Journals (Sweden)

    D. Rus

    2013-12-01

    Full Text Available It is generally known that the friction and wear between polymers and polished steel surfaces has a special character, the behaviour to friction and wear of a certain polymer might not be valid for a different polymer, moreover in dry friction conditions. In this paper, we study the reaction to wear of certain polymers with short glass fibres on different steel surfaces, considering the linear friction contact, observing the friction influence over the metallic surfaces wear. The paper includes also its analysis over the steel’s wear from different points of view: the reinforcement content influence and tribological parameters (load, contact pressure, sliding speed, contact temperature, etc.. Thus, we present our findings related to the fact that the abrasive component of the friction force is more significant than the adhesive component, which generally is specific to the polymers’ friction. Our detections also state that, in the case of the polyamide with 30% glass fibres, the steel surface linear wear rate order are of 10-4 mm/h, respectively the order of volumetric wear rate is of 10-6 cm3 /h. The resulting volumetric wear coefficients are of the order (10-11 – 10-12 cm3/cm and respectively linear wear coefficients of 10-9 mm/cm.