Protection device for a thermonuclear device

International Nuclear Information System (INIS)

Kawashima, Shuichi.

1986-01-01

Purpose: To exactly detect the void coefficients of coolants even under high magnetic fields thereby detect the overheat of a thermonuclear device at an early stage. Constitution: The protecting device of this invention comprises a laser beam generation device, a laser beam detection device and an accident detection device. The laser generation device always generates laser beams, which are permeated through coolants and detected by the laser beam detection device, the optical amount of which is transmitted to the accident detection device. The accident detection device judges the excess or insufficiency of the detected optical amount with respect to the optical amount of the laser beams under the stationary state as a reference and issues an accident signal. Since only the optical cables that do not undergo the effect of the magnetic fields are exposed to high magnetic fields in the protection device of this invention, a high reliability can be maintained. (Kamimura, M.)

Biotribological evaluation of artificial disc arthroplasty devices: influence of loading and kinematic patterns during in vitro wear simulation

Science.gov (United States)

Yue, James J.; Garcia, Rolando; Basson, Janet; Schwiesau, Jens; Fritz, Bernhard; Blömer, Wilhelm

2008-01-01

Wear simulation is an essential pre-clinical method to predict the mid- and long-term clinical wear behavior of newly introduced devices for total disc arthroplasty. The main requirement of a suitable method for spinal wear simulation has to be the ability to distinguish between design concepts and allow for a direct comparison of predicate devices. The objective of our study was to investigate the influence of loading and kinematic patterns based on two different protocols for spinal wear simulation (ISO/FDIS 18192-1 (2006) and ASTM F2423-05). In vitro wear simulation was performed with six activ® L lumbar artificial disc devices (Aesculap Tuttlingen, Germany). The applied kinematic pattern of movement was multidirectional for ISO (elliptic track) and unidirectional with a curvilinear shape for ASTM. Testing was done for 10 million cycles in the ISO loading mode and afterwards with the same specimens for 5 million cycles according to the ASTM protocol with a customized six-station servohydraulic spinal wear simulator (EndoLab Thansau, Germany). Gravimetrical and geometrical wear assessment, a slide track analysis correlated to an optical surface characterization, and an estimation of particle size and morphology were performed. The gravimetric wear rate for the first 10 million cycles was ISOinitial = 2.7 ± 0.3 mg/million cycles. During the ASTM test period (10–15 million cycles) a gravimetric wear rate of 0.14 ± 0.06 mg/million cycles was estimated. The wear rates between the ISO and ASTM driven simulations differ substantially (approximately 20-fold) and statistical analysis demonstrates a significant difference (p < 0.001) between the test groups. The main explanation of divergency between ISO and ASTM driven wear simulations is the multidirectional pattern of movement described in the ISO document resulting in a cross-shear stress on the polyethylene material. Due to previous retrieval observations, it seems to be very unlikely that a lumbar

Eye Protection in Kansas Schools.

Science.gov (United States)

Hay, Kenneth M.; And Others

A law passed by a state legislature requires that students in industrial arts shops and science laboratories must wear eye protective devices. Explanatory material presents the text of the bill and guidelines for implementation, including--(1) types of eye hazards, (2) types of protective devices, (3) administrating eye safety equipment, (4)…

Filtration of nanoparticles - Application to respiratory protecting devices

International Nuclear Information System (INIS)

Brochot, C.

2012-01-01

This study aims to determine how the respiratory protective devices (RPD), whose performances are qualified for particles above 100 nm, are effective for nanoparticles. Indeed, if the use of a collective filtration is inadequate, wearing a RPD is the last protection recommended. A literature review showed that no research concerned the effectiveness of half-masks for nanoparticles. The test bench ETNA has been sized and built to overcome these lacks. Two half masks were tested according to different configurations: constant flow rate and cyclic flow rate (average flow of 84 L /min), particle size (from 5 to 100 nm), positions of the mask (sealed, usual, or with calibrated leaks). The results show that, since the RPD contain high efficiency filter media (without charged fibers) for the most penetrating particle size (100 nm - 300 nm), the RPD is more efficient for nanoparticles. Furthermore, the results obtained in the presence of actual and calibrated leaks, highlighted the importance of face seal leakages in determining the performance of RPD. A model for calculating the protection factor was established based on the balance between the airflow through the filter and the leak. This model was validated using measurements obtained in the presence of calibrated leaks, and applied for the analysis of our results in usual position. (author)

Scratch, wear and corrosion resistant organic inorganic hybrid materials for metals protection and barrier

International Nuclear Information System (INIS)

Barletta, M.; Gisario, A.; Puopolo, M.; Vesco, S.

2015-01-01

Highlights: • Polysiloxane coatings as protective barriers to delay erosion/corrosion of Fe 430 B metal substrates. • Methyl groups feature a very small steric hindrance and confer ductility to the Si–O–Si backbone. • Phenyl groups feature a larger steric hindrance, but they ensure stability and high chemical inertness. • Remarkable adhesion to the substrate, good scratch resistance and high wear endurance. • Innovative ways to design of long lasting protective barriers against corrosion and aggressive chemicals. - Abstract: Polysiloxanes are widely used as protective barriers to delay erosion/corrosion and increase chemical inertness of metal substrates. In the present work, a high molecular weight methyl phenyl polysiloxane resin was designed to manufacture a protective coating for Fe 430 B structural steel. Methyl groups feature very small steric hindrance and confer ductility to the Si–O–Si backbone of the organic inorganic hybrid resin, thus allowing the achievement of high thickness. Phenyl groups feature larger steric hindrance, but they ensure stability and high chemical inertness. Visual appearance and morphology of the coatings were studied by field emission scanning electron microscopy and contact gauge surface profilometry. Micro-mechanical response of the coatings was analyzed by instrumented progressive load scratch, while wear resistance by dry sliding linear reciprocating tribological tests. Lastly, chemical inertness and corrosion endurance of the coatings were evaluated by linear sweep voltammetry and chronoamperometry in aggressive acid environment. The resulting resins yielded protective materials, which feature remarkable adhesion to the substrate, good scratch resistance and high wear endurance, thus laying the foundations to manufacture long lasting protective barriers against corrosion and, more in general, against aggressive chemicals

A diamond-like carbon film for wear protection of steel

International Nuclear Information System (INIS)

Harris, S.J.; Weiner, A.M.; Tung, S.C.; Simko, S.J.; Militello, M.C.

1993-01-01

We have deposited diamond-like carbon (DLC) and amorphous SiN films on a tool steel coupon. In order to make the DLC adhere to the metal, we used an interlayer of amorphous SiN, taking advantage of the fact that the SiN coating adheres to the metal and the DLC adheres to the SiN. The DLC/SiN-coated substrate showed a significant reduction in friction compared with either uncoated or SiN-coated substrates in our laboratory bench tester after lubricated sliding for 30 h. In addition, on the basis of surface profilometry analysis, the DLC/SiN-coated plate showed less wear and a much smoother surface. The films were analyzed using X-ray photo-electron spectroscopy and sputter depth profiling. Our results suggest that DLC is a promising coating for wear protection. (orig.)

Corrosion and wear protective composition modulated alloy coatings based on ternary Ni-P-X alloys

DEFF Research Database (Denmark)

Leisner, P.; Benzon, M. E.; Christoffersen, Lasse

1996-01-01

Scattered reporting in the litterature describes a number of ternary Ni-P-X alloyes (where X can be Co, Cr, Cu, Mo, Pd, Re or W) with promising corrosin and wear protective performance. Based on a systematic study of Ni-P-X alloys it is the intention to produce coatings with improved corrosion...... and wear performance compared with conventional coatings like electroless nickel, hard chromioum and anodised aluminium....

Effect of air-filled vest on exercise-heat strain when wearing ballistic protection.

Science.gov (United States)

Adams, J D; McDermott, Brendon P; Ridings, Christian B; Mainer, Lacey L; Ganio, Matthew S; Kavouras, Stavros A

2014-10-01

The purpose was to determine if an air-filled vest worn under ballistic protection reduces physiological strain during exercise in the heat either while wearing a tactical military (TM) protective vest or a law enforcement (LE) concealable vest. Sixteen men (24.5±3.9 years; 179.5±5.6 cm; 84.6±12.3kg) performed either two or four trials of treadmill walking (1.34 m s(-1); 2% grade) over 120 min in a hot, dry environment (37°C, 30% relative humidity, wind speed 3.5 m s(-1)). Participants completed trials wearing a TM or LE, with either the air-filled vest (TMa; LEa) or no vest (TMc; LEc) in random order. During trials, participants wore Army Combat Uniform pants. Physiological variables measured every 5min included gastrointestinal temperature (T GI), mean skin temperature (T sk), and heart rate (HR). Sweat rate (SR) was calculated based on fluid intake and body mass measures. In the tactical trial (TMa versus TMc), no differences in final T GI (38.2±0.4 versus 38.3±0.4°C), T sk (35.0±0.9 versus 35.0±1.0°C), HR (142±19 versus 143±23 bpm) existed (P>0.05). In the LE trials (LEa versus LEc), no differences in final T GI (38.0±0.4 versus 38.1±0.3°C), T sk (35.3±1.1 versus 35.6±0.9°C), HR (132±20 versus 135±20 bpm) existed (P>0.05). Despite slightly higher SR, there was no statistical difference in TM (1.15±1.13 versus 1.54±0.46 l h(-1); P=0.10) or in LE (1.39±0.52 versus 1.37±0.18 l h(-1); P=0.35) during trials. When participants exercised with a TM or LE while wearing the air-filled vest, there were no thermoregulatory and physiological differences compared to control trials. In our testing conditions, the air-filled device had little effect on physiological responses during prolonged mild exercise in the heat. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

The rectal temperature estimation method based on tympanic temperature for workers wearing protective clothing in nuclear facilities

International Nuclear Information System (INIS)

Takahashi, Naoki; Lee, Joo-Young; Wakabayashi, Hitoshi; Tochihara, Yutaka

2012-01-01

At nuclear facilities, workers wear impermeable protective clothing to prevent radioactive contamination during inspection and maintenance activities. The heat stroke risk of the workers wearing protective clothing gradually increases, because of retaining heat and humidity inside of protective clothing. Normally, the rectal temperature is used to manage the heat stroke risk. But the rectal temperature measurement is very difficult at the working place. We have already reported that the measurement of infrared tympanic temperature is more realistic than that of rectal temperature to manage the heat stroke risk. But tympanic temperature indicates high temperature compared to rectal temperature. So, the use of the tympanic temperature overestimates core temperature and decreases the work efficiency. Therefore, we attempted to make formulas to predict rectal temperature from measured tympanic temperature, and to use calculated rectal temperature for safer and more efficient management. The rectal temperature predicted with the formulas agreed with the actual measurement within the range of measurement error (±0.1degC). Combination of tympanic temperature measurement and heat rate evaluation enabled the safer management of the heat stroke risk with wearing protective clothing. (author)

Wear mechanisms and friction parameters for sliding wear of micron-scale polysilicon sidewalls

NARCIS (Netherlands)

Alsem, D. H.; van der Hulst, R.; Stach, E. A.; Dugger, M. T.; De Hosson, J. Th. M.; Ritchie, R. O.

As tribological properties are critical factors in the reliability of silicon-based microelectromechanical systems, it is important to understand what governs wear and friction. Average dynamic friction, wear volumes and morphology have been studied for polysilicon devices fabricated using the

Radiostethoscopes: an innovative solution for auscultation while wearing protective gear.

Science.gov (United States)

Candiotti, Keith A; Rodriguez, Yiliam; Curia, Luciana; Saltzman, Bruce; Shekhter, Ilya; Rosen, Lisa; Birnbach, David J

2011-01-01

To demonstrate a radiostethoscope that could be modified and successfully used while wearing protective gear to solve the problem of auscultation in a hazardous material or infectious disease setting. This study was a randomized, prospective, and blinded investigation. The study was conducted at the University of Miami-Jackson Memorial Hospital Center for Patient Safety. Two blinded anesthesiologists using a radiostethoscope performed a total of 100 assessments (50 each) to evaluate endotracheal tube position on a human patient simulator (HPS). Each lung of the HPS was ventilated separately using a double lumen tube. Four ventilation patterns (ie, right lung ventilation only; left lung ventilation only; ventilation of both lungs; and an esophageal intubation or no breath sounds) were simulated. The ventilation pattern was determined randomly and participants were blinded. An Ambu-Bag was used for ventilation. An assistant moved the radiostethoscope to the right and left lung fields and then to the abdomen of the HPS while ventilating. Subjects had to identify the ventilation pattern after listening to all three locations. A third member of the research team collected responses. Each subject, who wore both types of respirator (positive and negative), performed a total of 25 trials. Participants later compared the two types of respirators and their ability to auscultate for breath sounds. Subjects were able to verify the correct ventilation pattern in all attempts (100 percent). Radiostethoscopes appear to provide a viable solution for the problem of patient auscultation while wearing protective gear.

Influence on grip of knife handle surface characteristics and wearing protective gloves.

Science.gov (United States)

Claudon, Laurent

2006-11-01

Ten subjects were asked to apply maximum torques on knife handles with either their bare hand or their hand wearing a Kevlar fibre protective glove. Four knife handles (2 roughnesses, 2 hardnesses) were tested. Surface electromyograms of 6 upper limb and shoulder muscles were recorded and subject opinions on both knife handle hardness and friction in the hand were also assessed. The results revealed the significant influence of wearing gloves (pgloves greatly increased the torque independently of the other two parameters. Under the bare hand condition, a 90 degrees ShA slightly rough handle provided the greatest torque. Subject opinion agreed with the observed effects on recorded torque values except for the hardness factor, for which a preference for the 70 degrees ShA value over the 90 degrees ShA value emerged.

Evaluation of novel disposable, light-weight radiation protection devices in an interventional radiology setting: a randomized controlled trial.

Science.gov (United States)

Uthoff, Heiko; Peña, Constantino; West, James; Contreras, Francisco; Benenati, James F; Katzen, Barry T

2013-04-01

Radiation exposure to interventionalists is increasing. The currently available standard radiation protection devices are heavy and do not protect the head of the operator. The aim of this study was to evaluate the effectiveness and comfort of caps and thyroid collars made of a disposable, light-weight, lead-free material (XPF) for occupational radiation protection in a clinical setting. Up to two interventional operators were randomized to wear a XPF or standard 0.5-mm lead-equivalent thyroid collars in 60 consecutive endovascular procedures requiring fluoroscopy. Simultaneously a XPF cap was worn by all operators. Radiation doses were measured using dosimeters placed outside and underneath the caps and thyroid collars. Wearing comfort was assessed at the end of each procedure on a visual analog scale (0-100 [100 = optimal]). Patient and procedure data did not differ between the XPF and standard protection groups. The cumulative radiation dose measured outside the cap was 15,700 μSv and outside the thyroid collars 21,240 μSv. Measured radiation attenuation provided by the XPF caps (n = 70), XPF thyroid collars (n = 40), and standard thyroid collars (n = 38) was 85.4% ± 25.6%, 79.7% ± 25.8% and 71.9% ± 34.2%, respectively (mean difference XPF vs standard thyroid collars, 7.8% [95% CI, -5.9% to 21.6%]; p = 0.258). The median XPF cap weight was 144 g (interquartile range, 128-170 g), and the XPF thyroid collars were 27% lighter than the standard thyroid collars (p disposable caps and thyroid collars made of XPF were assessed as being comfortable to wear, and they provide radiation protection similar to that of standard 0.5-mm lead-equivalent thyroid collars.

A preliminary examination of neurocognitive performance and symptoms following a bout of soccer heading in athletes wearing protective soccer headbands.

Science.gov (United States)

Elbin, R J; Beatty, Amanda; Covassin, Tracey; Schatz, Philip; Hydeman, Ana; Kontos, Anthony P

2015-01-01

This study compared changes in neurocognitive performance and symptom reports following an acute bout of soccer heading among athletes with and without protective soccer headgear. A total of 25 participants headed a soccer ball 15 times over a 15-minute period, using a proper linear heading technique. Participants in the experimental group completed the heading exercise while wearing a protective soccer headband and controls performed the heading exercise without wearing the soccer headband. Neurocognitive performance and symptom reports were assessed before and after the acute bout of heading. Participants wearing the headband showed significant decreases on verbal memory (p = 0.02) compared with the no headband group, while the no headband group demonstrated significantly faster reaction time (p = 0.03) than the headband group following the heading exercise. These findings suggest that protective soccer headgear likely does not mitigate the subtle neurocognitive effects of acute soccer heading.

Inventing urine incontinence devices for women.

Science.gov (United States)

Pieper, B; Cleland, V; Johnson, D E; O'Reilly, J L

1989-01-01

Nurses have long been aware of the devastating effects of urinary incontinence on women. Although women may find diapers, pads and protective clothing valuable protection, there are few options for a continuous wear, external urine incontinence device (EUID). Inventors have attempted to develop an EUID since ancient times; the first United States patent for an EUID was awarded in 1949. The purpose of this paper is to review technological considerations for development of an external urinary incontinence device for women. Patents and products illustrate the considerations.

Brake wear warning device: A concept

Science.gov (United States)

Hawkins, S. F.

1973-01-01

Heat-insulated wire is introduced through brake shoe and partially into brake lining. Wire is connected to positive terminal and light bulb. When brakes wear to critical point, contact between wire and wheel drum grounds circuit and turns on warning light.

Automatic coordination of protection devices in distribution system

International Nuclear Information System (INIS)

Comassetto, L.; Bernardon, D.P.; Canha, L.N.; Abaide, A.R.

2008-01-01

Among the several components of distribution systems, protection devices present a fundamental importance, since they aim at keeping the physical integrity not only of the system equipment, but also of the electricians' team and the population in general. The existing tools today in the market that carry out the making of protection studies basically draw curves, and need direct user's interference for the protection devices adjustment and coordination analyses of selectivity, being susceptible to the user's mistakes and not always considering the best technical and economical application. In Brazil, the correct application of the protection devices demand a high amount of time, being extremely laborious due to the great number of devices (around 200 devices), besides the very dynamic behaviour of distribution networks and the need for constant system expansion. This article presents a computational tool developed with the objective of automatically determining the adjustments of all protection devices in the distribution networks to obtain the best technical application, optimizing its performance and making easier protection studies. (author)

Arc-Sprayed Fe-Based Coatings from Cored Wires for Wear and Corrosion Protection in Power Engineering

Directory of Open Access Journals (Sweden)

Korobov Yury

2018-02-01

Full Text Available High wear and corrosion of parts lead to an increase in operating costs at thermal power plants. The present paper shows a possible solution to this problem through the arc spraying of protective coatings. Cored wires of the base alloying system Fe-Cr-C were used as a feedstock. Rise of wear- and heat-resistance of the coatings was achieved by additional alloying with Al, B, Ti, and Y. The wear and heat resistance of the coatings were tested via a two-body wear test accompanied by microhardness measurement and the gravimetric method, respectively. A high-temperature corrosion test was performed at 550 °C under KCl salt deposition. The porosity and adhesion strengths of the coatings were also evaluated. The microstructure was investigated with a scanning electron microscope (SEM unit equipped with an energy dispersive X-ray (EDX microanalyzer, and the phase composition was assessed by X-ray diffractometry. The test results showed the positive influence of additional alloying with Y on the coating properties. A comparison with commercial boiler materials showed that the coatings have the same level of heat resistance as austenite steels and are an order of magnitude higher than that of pearlite and martensite-ferrite steels. The coatings can be applied to wear- and heat-resistant applications at 20–700 °C.

Touching for attention: How flight instructors support a pilot wearing a view-limiting device

DEFF Research Database (Denmark)

Nevile, Maurice Richard; Tuccio, William A.

2018-01-01

We use video recordings from pilot training flights to show how instructors support attention of a student wearing ‘foggles’, a view-limiting device designed to train pilots to fly by reference only to the cockpit flight instruments. The instructors touch cockpit displays with a pointing finger...... demonstrates a technique for controlling descent. The data examples are taken from a corpus of almost 100 hours of video recordings of actual in-flight instruction. We consider how our analyses can inform flight instructor training and improve instructor effectiveness, for example by revealing possible...

Protective device for battery to protect against heavy discharge

Energy Technology Data Exchange (ETDEWEB)

1979-02-08

The protective device according to the invention switches the equipment being supplied from the battery at a pre-determined discharge voltage by means of a switching device controlled by monitoring equipment. A semi-conductor element is used as the switching device. The current taken from the battery flows through the semi-conductor element to the equipment and to the monitoring device. When the discharge voltage is reached the semi-conductor element blocks. The semi-conductor switch can consist of transistors. The invention is explained by means of drawings and examples.

Attenuation of earmuffs used simultaneously with respiratory protective devices

Directory of Open Access Journals (Sweden)

Emil Kozłowski

2017-06-01

Full Text Available Background: In the work environment, apart from the noise, employees may be exposed to other harmful factors. Therefore, they wear hearing protectors and other personal protective equipment. The aim of the study was to determine whether simultaneous use of earmuffs and respiratory protective devices affects the attenuation of earmuffs. Material and Methods: The study was conducted in laboratory conditions using the subjective REAT (Real Ear Attenuation at Threshold and objective MIRE (Microphone in Real Ear methods. The REAT method was used to measure sound attenuation of earmuffs, while MIRE was used to determine changes in attenuation of earmuffs due to the use of other personal protective equipment. Results: The study showed reduction in attenuation of earmuffs due to the use of a full face mask up to 20 dB. Using a full face mask causes that attenuation of earmuffs in the low frequency range is close to zero. Reduction in attenuation due to the use of half masks for complete with particle filters (half masks is 3–15 dB. Simultaneous use of earmuffs and filtering half masks makes small changes in attenuation not exceeding 3 dB. Conclusions: The study showed that full face masks give the greatest reduction in attenuation of earmuffs. On the other hand, the least reduction is observed in the case of filtering half masks. There is a significant difference between the reduction in attenuation of earmuffs worn with half masks for complete with particle filters because they may be equipped with different kind of the head strap. Med Pr 2017;68(3:349–361

Wear monitoring of protective nitride coatings using image processing

DEFF Research Database (Denmark)

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

2010-01-01

-meter with up to 105 19 repetitive cycles, eventually leaving the embedded TiN signal layer uncovered at the bottom the wear scar. 20 The worn surface was characterized by subsequent image processing. A color detection of the wear scar with 21 the exposed TiN layer by a simple optical imaging system showed......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...... a significant increase up to a factor of 2 of 22 the relative color values from the TiAlN top layers to the embedded TiN signal layers. This behavior agrees 23 well with the results of reflectance detection experiment with a red laser optical system on the same system. 24 Thus we have demonstrated that image...

New Challenges in Tribology: Wear Assessment Using 3D Optical Scanners.

Science.gov (United States)

Valigi, Maria Cristina; Logozzo, Silvia; Affatato, Saverio

2017-05-18

Wear is a significant mechanical and clinical problem. To acquire further knowledge on the tribological phenomena that involve freeform mechanical components or medical prostheses, wear tests are performed on biomedical and industrial materials in order to solve or reduce failures or malfunctions due to material loss. Scientific and technological advances in the field of optical scanning allow the application of innovative devices for wear measurements, leading to improvements that were unimaginable until a few years ago. It is therefore important to develop techniques, based on new instrumentations, for more accurate and reproducible measurements of wear. The aim of this work is to discuss the use of innovative 3D optical scanners and an experimental procedure to detect and evaluate wear, comparing this technique with other wear evaluation methods for industrial components and biomedical devices.

Safeguards of basic protection devices, high-protection devices, full-protection devices and school X-ray devices. Guideline for manufacturer and evaluating experts, rev. 1.0; Sicherheitsvorrichtungen von Basisschutzgeraeten, Hochschutzgeraeten, Vollschutzgeraeten und Schulroentgeneinrichtungen. Anforderungen fuer die Bauartpruefung nach der Roentgenverordnung. Leitfaden fuer Hersteller und Gutachter Rev. 1.0

Energy Technology Data Exchange (ETDEWEB)

Dombrowski, Harald; Grottker, Ulrich; Pullner, Bjoern; Roettger, Annette; Zwiener, Roland

2017-07-15

This report describes the PTB requirements for engineered safeguards of basic-protection devices, high-protection devices, full-protection devices and school X-ray devices within the framework of type tests according to the German X-ray Ordinance. It contains detailed requirements for the hard- and software to ensure the required safety level. Especially manufacturers and evaluators of such X-ray tube assemblies are addressed.

Protection of 310l Stainless Steel from Wear at Elevated Temperatures using Conicraly Thermal Spray Coatings with and without Sic Addition

Science.gov (United States)

Zhang, Yan; Zhang, Tao; Li, Kaiyang; Li, Dongyang

2017-10-01

Due to its high oxidation resistance, 310L stainless steel is often used for thermal facilities working at high-temperatures. However, the steel may fail prematurely at elevated temperatures when encounter surface mechanical attacks such as wear. Thermal spray coatings have been demonstrated to be effective in protecting the steel from wear at elevated temperatures. In this study, we investigated the effectiveness of high velocity oxy-fuel(HVOF) spraying CoNiCrAlY/SiC coatings in resisting wear of 310L stainless steel at elevated temperature using a pin-on-disc wear tester. In order to further improve the performance of the coating, 5%SiC was added to the coating. It was demonstrated that the CoNiCrAlY/SiC coating after heat treatment markedly suppressed wear. However, the added SiC particles did not show benefits to the wear resistance of the coating. Microstructures of CoNiCrAlY coatings with and without the SiC addition were characterized in order to understand the mechanism responsible for the observed phenomena.

Design And Development Of An Automatic Single Phase Protective Device Using Ssr

Directory of Open Access Journals (Sweden)

Michael E.

2017-10-01

Full Text Available Since the discovery of energy safety has been a paramount subject matter. This we can see in todays electrical systems where protective devices such as fuse and circuit breakers are used to prevent fire hazards resulting from overload overvoltage and short circuits. However with all the revolution in technology these options may be considered less smart since the fuse made with wire strands calculated for specific current capacity faults permanently when the specified current rating is exceeded. While the circuit breaker which is made up of mechanical switch fails as a result of carbon forming and the wearing away of the contacts because of arcing. As a means of improvement this paper presents the design and development of an automatic single phase protective device using solid state relay SSR. This study is to ensure automatic cut off from power supply in cases of overvoltage above 240 V AC or when overload and short circuit current above 8amps is detected without permanent damage of a fuse placed along current path. Also the design will ensure that there is an automatic close circuit whenever the trigger switch is momentary switch is closed. The system is achieved via the use of PIC micro-controller current sensor and other discrete components. The system is tested and works well inhibiting the frequent faulting of fuses. It also helps to prevent hazard as a result of overvoltage overload and short circuit and ensures a close circuit when the trigger switch is closed.

Noise Attenuation Loss Due to Wearing APEL Eye Protection with Ear-Muff Style Headset Systems

Science.gov (United States)

2012-02-14

USAARL Report No. 2012-09 Noise Attenuation Loss Due to Wearing APEL Eye Protection with Ear-Muff Style Headset Systems By Efrem Reeves Elmaree...Cameron Station, Alexandria, Virginia 22314. Orders will be expedited if placed through the librarian or other person designated to request...not be construed as an official Department of the Army position, policy, or decision, unless so designated by other official documentation. Citation

Development of device for grid spring fatigue and a cell-based fuel rod fretting wear tests

International Nuclear Information System (INIS)

Kim, Hyung Kyu; Yoon, Kyung Ho; Kang, Heung Seok; Song, Kee Nam

2001-05-01

As an activity of experimental research on the cause and the remedy of LWR fuel fretting failure, developed is test equipment for fatigue of grid spring and cell-based fuel rod fretting wear test. The equipment enables to perform the fretting wear test in the case of gap existence between spring and cladding, which has not been possible by the previously developed one (KAERI/TR-1570/2000). It can also provide fatigue test capability with the frequency of more than 10 Hz. Used are a servo-motor, an eccentric cylinder and lever mechanism for driving system as was similarly used for the previous equipment. In fretting wear test, up to 2 span-length of a fuel cladding tube can be accommodated. For fatigue test, on the other hand, a device for clamping the spring fixture is installed additionally. As a feature of the present equipment, the gap or the contacting force between a spring and a tube can be adjusted during the fretting wear test, while an initial spring force can be simulated for the fatigue test. Tests will be conducted in air at room temperature. In this report, every part of the equipment is explained with photographs, which will provide an easy understanding. Test procedure such as specimen installation, sequence of operation and program handling is also given. As a performance test of the present equipment, displacement range is measured when the hinge of the lever locates at its maximum and minimum positions. This will be used as basic information when additional eccentric cylinder is necessary for different displacement ranges

Wear protection in cutting tool applications by PACVD (Ti,Al)N and Al2O3 coatings

International Nuclear Information System (INIS)

Kathrein, M.; Heiss, M.; Rofner, R.; Schleinkofer, U.; Schintlmeister, W.; Schatte, J.; Mitterer, C.

2001-01-01

Various (Ti,Al)N-, Al 2 O 3 -, and (Ti,Al)N/Al 2 O 3 multilayer coatings were deposited onto cemented carbide cutting tool inserts by a plasma assisted chemical vapor deposition (PACVD) technique. Al 2 O 3 coatings were deposited using the gaseous mixture AlCl 3 , Ar, H 2 , and O 2 . (Ti,Al)N intermediate layers were deposited in the same device using the process mentioned and the gases AICl 3 , Ar, H 2 , TiCl 4 and N 2 . The unique properties of (Ti,Al)N/Al 2 O 3 multilayer coatings result in superior wear protection for cutting inserts applied in severe multifunction cutting processes. The influence of different deposition temperatures an structure and properties of the coatings like crystallographic phases, chemical composition, mechanical and technological properties is shown. PACVD (Ti,Al)N/Al 2 O 3 coated cutting inserts with fine grained crystalline α/κ-Al 2 O 3 offer performance advantages which are superior with respect to coatings deposited by chemical vapor deposition (CVD) due to the low deposition temperature applied. (author)

Gate protective device for SOS array

Science.gov (United States)

Meyer, J. E., Jr.; Scott, J. H.

1972-01-01

Protective gate device consisting of alternating heavily doped n(+) and p(+) diffusions eliminates breakdown voltages in silicon oxide on sapphire arrays caused by electrostatic discharge from person or equipment. Diffusions are easily produced during normal double epitaxial processing. Devices with nine layers had 27-volt breakdown.

Complex technique for studying the machine part wear

International Nuclear Information System (INIS)

Grishko, V.A.; Zhushma, V.F.

1981-01-01

A technique to determine the wear of steel details rolling with sliding with circulatory lubrication is suggested. The functional diagram of the experimental device and structural diagrams of equipment to register the wear of tested samples and forming the lubricating layer between them, are considered. Results of testing three conples of disc samples and the data characterizing the dependence of sample wear on the value of contact stress are presented. The peculiarity of the device used is synchronous registering of the lubricating layer formation in the place of contact and detail mass loss in time which is realized correspondingly over discharge voltage on the lubricating layer and the intensity of radiation from detail wear products activated by neutrons. On the basis, of the investigation the conclusion is made that MEhF-1 oil has a greater antiwear effectiveness than the universal TAD-17 1 oil used presently [ru

Effect of cold conditions on manual performance while wearing petroleum industry protective clothing.

Science.gov (United States)

Wiggen, Øystein Nordrum; Heen, Sigri; Færevik, Hilde; Reinertsen, Randi Eidsmo

2011-01-01

The purpose of this study was to investigate manual performance and thermal responses during low work intensity in persons wearing standard protective clothing in the petroleum industry when they were exposed to a range of temperatures (5, -5, -15 and -25℃) that are relevant to environmental conditions for petroleum industry personnel in northern regions. Twelve men participated in the study. Protective clothing was adjusted for the given cold exposure according to current practices. The subjects performed manual tests five times under each environmental condition. The manual performance test battery consisted of four different tests: tactile sensation (Semmes-Weinstein monofilaments), finger dexterity (Purdue Pegboard), hand dexterity (Complete Minnesota dexterity test) and grip strength (grip dynamometer). We found that exposure to -5℃ or colder lowered skin and body temperatures and reduced manual performance during low work intensity. In conclusion the current protective clothing at a given cold exposure is not adequate to maintain manual performance and thermal balance for petroleum workers in the high north.

An application of residual current protective device at electrical installation

International Nuclear Information System (INIS)

Firman Silitonga

2008-01-01

In an electrical installation, a protection for overload and short circuit are always to be installed. In addition to the installation, it is necessary to be installed a protection device for residual current because both the short circuit and the overload device protection will not work for the residual current. The quantity of the residual current must be defined first at any electrical installation to define an appropriate residual current protection so that not every residual current will break the circuit down. This paper will explain a method how to install a residual protection device for 3500 VA or more at TN and TT of earthing system. (author)

The friction wear of electrolytic composite coatings

International Nuclear Information System (INIS)

Starosta, R.

2002-01-01

The article presents the results of investigation of wear of galvanic composite coatings Ni-Al 2 O 3 and Ni-41%Fe-Al 2 O 3 . The diameter of small parts of aluminium oxide received 0.5; 3; 5 μm. Investigations of friction sliding were effected on PT3 device at Technical University of Gdansk. Counter sample constituted a funnel made of steel NC6 (750 HV). Increase of wear coatings together with the rise of iron content in matrix is observed. The rise of sizes of ceramic particles caused decrease of wear of composite coatings, but rise of steel funnel wear. The friction coefficient increased after ceramic particle s were built in coatings. The best wear resistance characterized Ni-41%Fe-Al 2 O 3 coatings containing 2.2x10 6 mm -2 ceramic particles. (author)

Device Data Protection in Mobile Healthcare Applications

Science.gov (United States)

Weerasinghe, Dasun; Rajarajan, Muttukrishnan; Rakocevic, Veselin

The rapid growth in mobile technology makes the delivery of healthcare data and services on mobile phones a reality. However, the healthcare data is very sensitive and has to be protected against unauthorized access. While most of the development work on security of mobile healthcare today focuses on the data encryption and secure authentication in remote servers, protection of data on the mobile device itself has gained very little attention. This paper analyses the requirements and the architecture for a secure mobile capsule, specially designed to protect the data that is already on the device. The capsule is a downloadable software agent with additional functionalities to enable secure external communication with healthcare service providers, network operators and other relevant communication parties.

Study of the Effective Parameters on the Making Use of Protective Devices

Directory of Open Access Journals (Sweden)

Y Tabaraie

2012-05-01

Full Text Available

Background and objectives

Noise threats health of many groups of industrial workers and causes hearing loss. Use of personal protective device is the best control method to protect against hazardous conditions. Hence, this investigation was carried out to determine situation of using of protective devices and effective parameters on it, in Qom province workers community in 2006.

Methods

This research is descriptive-sectional study. Sample volume was designed 378 persons working in factories in Qom. First of all, list of Qom factories with noise pollution problems, were collected and 30 important factories among them were selected randomly. In the second stage, 378 persons were selected randomly from workers. The interest information was obtained by questionnaire and collected data were analyzed by SPSS software.

Results

The obtained results showed that, 83.6% of workers have been using ear protective devices. 296 of them, which were using ear protective devices, had an occupational hygienist in their workplaces. This research also showed that, 109 workers that used ear protective devices, had moderate knowledge level. Moreover, 82.5% of trained workers have used ear protective devices. The statistical analysis of the results showed that there were no significant relationship between use of ear protective devices and existence of occupational hygienist in workplace, knowledge and age of workers, worker’s antecedent, physical health of workers and kind of ear protective devices (p> 0.05. 

Conclusion

These results showed that among all considered parameters; only four parameters were effective in using ear protective devices; education of workers before employment, head workman and employer’s knowledge level, factories facilitation and kind of ear protective devices.

Insulated skin temperature as a measure of core body temperature for individuals wearing CBRN protective clothing

International Nuclear Information System (INIS)

Richmond, V L; Wilkinson, D M; Blacker, S D; Horner, F E; Carter, J; Rayson, M P; Havenith, G

2013-01-01

This study assessed the validity of insulated skin temperature (T is ) to predict rectal temperature (T re ) for use as a non-invasive measurement of thermal strain to reduce the risk of heat illness for emergency service personnel. Volunteers from the Police, Fire and Rescue, and Ambulance Services performed role-related tasks in hot (30 °C) and neutral (18 °C) conditions, wearing service specific personal protective equipment. Insulated skin temperature and micro climate temperature (T mc ) predicted T re with an adjusted r 2 = 0.87 and standard error of the estimate (SEE) of 0.19 °C. A bootstrap validation of the equation resulted in an adjusted r 2 = 0.85 and SEE = 0.20 °C. Taking into account the 0.20 °C error, the prediction of T re resulted in a sensitivity and specificity of 100% and 91%, respectively. Insulated skin temperature and T mc can be used in a model to predict T re in emergency service personnel wearing CBRN protective clothing with an SEE of 0.2 °C. However, the model is only valid for T is over 36.5 °C, above which thermal stability is reached between the core and the skin. (paper)

Neutron protection material and neutron protection devices made of such material

International Nuclear Information System (INIS)

Ries, W.

1984-01-01

This is concerned with a neutron protection material made of thermoplastic or thermosetting plastic from high molecule hydrocarbon compounds with particularly high hydrogen and carbon contents as braking or shielding material (moderator) for fast neutrons. The plastic can contain boron for absorbing low energy neutrons. The material is used to manufacture foil, plates, pipes, shielding walls, components, bodies for radiation protection equipment, devices and plant and for neutron protection clothes. (orig./HP) [de

A wear simulation study of nanostructured CVD diamond-on-diamond articulation involving concave/convex mating surfaces

Science.gov (United States)

Baker, Paul A.; Thompson, Raymond G.; Catledge, Shane A.

2015-01-01

Using microwave-plasma Chemical Vapor Deposition (CVD), a 3-micron thick nanostructured-diamond (NSD) layer was deposited onto polished, convex and concave components that were machined from Ti-6Al-4V alloy. These components had the same radius of curvature, 25.4mm. Wear testing of the surfaces was performed by rotating articulation of the diamond-deposited surfaces (diamond-on-diamond) with a load of 225N for a total of 5 million cycles in bovine serum resulting in polishing of the diamond surface and formation of very shallow, linear wear grooves of less than 50nm depth. The two diamond surfaces remained adhered to the components and polished each other to an average surface roughness that was reduced by as much as a factor of 80 for the most polished region located at the center of the condyle. Imaging of the surfaces showed that the initial wearing-in phase of diamond was only beginning at the end of the 5 million cycles. Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, and surface profilometry were used to characterize the surfaces and verify that the diamond remained intact and uniform over the surface, thereby protecting the underlying metal. These wear simulation results show that diamond deposition on Ti alloy has potential application for joint replacement devices with improved longevity over existing devices made of cobalt chrome and ultra-high molecular weight polyethylene (UHMWPE). PMID:26989457

Improved dental implant drill durability and performance using heat and wear resistant protective coatings.

Science.gov (United States)

Er, Nilay; Alkan, Alper; İlday, Serim; Bengu, Erman

2018-03-02

Dental implant drilling procedure is an essential step for implant surgery and frictional heat appeared in bone during drilling is a key factor affecting the success of an implant. The aim of this study is to increase the dental implant drill lifetime and performance using heat- and wear-resistant protective coatings hence to decrease the alveolar bone temperature caused by the dental implant drilling procedure. Commercially obtained stainless steel drills were coated with titanium aluminum nitride, diamond-like carbon, titanium boron nitride, and boron nitride coatings via magnetron-sputter deposition. Drilling procedure was performed on a bovine femoral cortical bone under the conditions mimicking clinical practice, where the tests were performed both under water-assisted cooling and under the conditions without any cooling was applied. Coated drill performances and durabilities were compared to that of three commonly used commercial drills which surfaces are made from namely; zirconia, black diamond and stainless steel. Protective coatings with boron nitride, titanium boron nitride and diamond-like carbon have significantly improved drill performance and durability. Especially boron nitride-coated drills have performed within safe bone temperature limits for 50 drillings even without any cooling is applied. Titanium aluminium nitride coated drills did not show any improvement over commercially obtained stainless steel drills. Surface modification using heat and wear resistant coatings is an easy and highly effective way to improve implant drill performance and durability, which can reflect positively on surgical procedure and healing period afterwards. The noteworthy success of different types of coatings is novel and likely to be applicable to various other medical systems.

Occlusal wear of provisional implant-supported restorations.

Science.gov (United States)

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

2015-02-01

Implant-supported provisional restorations should be resistant to occlusal wear. 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 methacrylate-based materials used to fabricate provisional implant-supported restorations. The materials were handled and cured according to the manufacturers' instructions. The three-body wear was measured 1 day, 3 days, 7 days, 4 weeks, and 8 weeks after curing using the ACTA wear device. Wear rate decreased significantly after 8 weeks compared with the first day for all tested materials, except for Estenia C&B. The three-body wear of two indirect laboratory composite resins, that is, Estenia C&B and Solidex, was significantly less compared with all other tested materials used for fabricating provisional implant-supported restorations. Of the chair side materials, the wear rate of Protemp Crown Paste was significantly less compared with the others materials used to fabricate chair side provisional implant-supported restorations. The methacrylate-based materials, Temdent Classic and Trim, showed extreme high wear rates. Based on the results of this laboratory study on long-term wear, the use of indirect composite resin is preferred over chair side methacrylate-based materials when the provisional implant-supported restoration has to be in service for a long period of time. Of the investigated materials, only Estenia C&B and Solidex showed wear rate comparable with posterior resin composites. © 2013 Wiley Periodicals, Inc.

Ten-year in vivo wear measurement of a fully congruent mobile bearing unicompartmental knee arthroplasty.

Science.gov (United States)

Price, A J; Short, A; Kellett, C; Beard, D; Gill, H; Pandit, H; Dodd, C A F; Murray, D W

2005-11-01

Polyethylene particulate wear debris continues to be implicated in the aetiology of aseptic loosening following knee arthroplasty. The Oxford unicompartmental knee arthroplasty employs a spherical femoral component and a fully congruous meniscal bearing to increase contact area and theoretically reduce the potential for polyethylene wear. This study measures the in vivo ten-year linear wear of the device, using a roentgenstereophotogrammetric technique. In this in vivo study, seven medial Oxford unicompartmental prostheses, which had been implanted ten years previously were studied. Stereo pairs of radiographs were acquired for each patient and the films were analysed using a roentgen stereophotogrammetric analysis calibration and a computer-aided design model silhouette-fitting technique. Penetration of the femoral component into the original volume of the bearing was our estimate of linear wear. In addition, eight control patients were examined less than three weeks post-insertion of an Oxford prosthesis, where no wear would be expected. The control group showed no measured wear and suggested a system accuracy of 0.1 mm. At ten years, the mean linear wear rate was 0.02 mm/year. The results from this in vivo study confirm that the device has low ten-year linear wear in clinical practice. This may offer the device a survival advantage in the long term.

Aplikace pro nositelnou elektroniku se systémem Android Wear

OpenAIRE

Šmejkal, Petr

2017-01-01

Semestrální práce „Aplikace pro nositelnou elektroniku se systémem" Android Wear popisuje základní principy komunikačních sítí - M2M (machine to machine), H2H (human to human) a D2D (device to device). Práce se dále zabývá nositelnými zařízeními, zejména chytrými hodinkami, dostupnými operačními systémy pro chytré hodinky a systémem Android, Android Wear. V praktické části je popsaná funkcionalita, vzhled a struktura vyvinuté aplikace pro Android Wear. The semestral project "Application fo...

Biocompatible wear-resistant thick ceramic coating

Directory of Open Access Journals (Sweden)

Vogt Nicola

2016-09-01

Full Text Available Sensitisation to immunologically active elements like chromium, cobalt or nickel and debris particle due to wear are serious problems for patients with metallic implants. We tested the approach of using a hard and thick ceramic coating as a wear-resistant protection of titanium implants, avoiding those sensitisation and foreign body problems. We showed that the process parameters strongly influence the coating porosity and, as a consequence, also its hardness.

Microprocessor protection devices: The present and the future

Directory of Open Access Journals (Sweden)

Gurevich Vladimir

2008-01-01

Full Text Available Paper presents the analysis of the basic constructive disadvantages of the present day microprocessor-based protective devices (MBR and offers the basic principles for creating a new MBR that can be used in newly constructed devices.

Protecting the historic centre of Venice. A coordinated analysis of the physical and perceived wear processes to define mitigating actions

Directory of Open Access Journals (Sweden)

Renata Codello

2014-05-01

Full Text Available The research aims to identify "physical" and "perceptual" wear factors of the historic center of Venice (with particular attention to the effects of anthropogenic pressure related to the phenomenon of tourism and to assess the damages they could produce to identify criteria and tools of mitigation and control. Research is part of the Action Plan "Protection and conservation of the heritage", established by the Plan of Management for the UNESCO Site of Venice and its Lagoon. Through a systemic reading and analysis of the forces of change in place, this study identifies the " macro-emergencies", i.e. the main factors that adversely affect the site’s safeguarding. The research project "Evaluation of wear processes and critical factors of the City of Venice and its lagoon, and its impact on the site’s protection" is part of the actions set out by the Management Plan of the UNESCO site of Venice and its Lagoon. The main objective of the project is the identification of physical and perceptual factors of wear, which threaten the conservation of the historical and artistic heritage of the historic center of Venice, with a particular focus on the effects of anthropogenic pressure linked to tourism, and the evaluation of their level of danger. A further objective is the recognition of measurable parameters (indicators for monitoring and, subsequently, mitigation strategies for the most significant phenomena.

Development of counting system for wear measurements using Thin Layer Activation and the Wearing Apparatus

Energy Technology Data Exchange (ETDEWEB)

França, Michel de A.; Suita, Julio C.; Salgado, César M., E-mail: mchldante@gmail.com, E-mail: suita@ien.gov.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

This paper focus on developing a counting system for the Wearing Apparatus, which is a device previously built to generate measurable wear on a given surface (Main Source) and to carry the fillings from it to a filter (second source). The Thin Layer Activation is a technique used to produce activity on one of the Wearing Apparatus' piece, this activity is proportional to the amount of material worn, or scrapped, from the piece's surface. Thus, by measuring the activity on those two points it is possible to measure the produced wear. The methodology used in this work is based on simulations through MCNP-X Code to nd the best specifications for shielding, solid angles, detectors dimensions and collimation for the Counting System. By simulating several scenarios, each one different from the other, and analyzing the results in the form of Counts Per Second, the ideal counting system's specifications and geometry to measure the activity in the Main Source and the Filter (second source) is chosen. After that, a set of previously activated stainless steel foils were used to reproduce the real experiments' conditions, this real experiment consists of using TLA and the Wearing Apparatus, the results demonstrate that the counting system and methodology are adequate for such experiments. (author)

Dental wear caused by association between bruxism and gastroesophageal reflux disease: a rehabilitation report

Directory of Open Access Journals (Sweden)

Naila Aparecida de Godoi Machado

2007-08-01

Full Text Available Bruxism is a pathological activity of the stomatognathic system that involves tooth grinding and clenching during parafunctional jaw movements. Clinical signs of bruxism are mostly related to dental wear and muscular and joint discomforts, but a large number of etiological factors can be listed, as local, systemic, psychological and hereditary factors. The association between bruxism, feeding and smoking habits and digestive disorders may lead to serious consequences to dental and related structures, involving dental alterations (wear, fractures and cracks, periodontal signs (gingival recession and tooth mobility and muscle-joint sensivity, demanding a multidisciplinary treatment plan. This paper presents a case report in which bruxism associated with acid feeding, smoking habit and episodes of gastric reflow caused severe tooth wear and great muscular discomfort with daily headache episodes. From the diagnosis, a multidisciplinary treatment plan was established. The initial treatment approach consisted of medical follow up with counseling on diet and smoking habits and management of the gastric disorders. This was followed by the installation of an interocclusal acrylic device in centric relation of occlusion (CRO for reestablishment of the occlusal stability, vertical dimension of occlusion, anterior guides and return to normal muscle activity (90-day use approximately. After remission of initial symptoms, oral rehabilitation was implemented in CRO by means of full resin composite restorations and new interocclusal device for protection of restorations. Satisfactory esthetics, improved function and occlusal stability were obtained after oral rehabilitation. The patient has attended annual follow-ups for the past 2 years. The multidisciplinary treatment seems to be the key for a successful rehabilitation of severe cases of dental wear involving the association of different health disorders.

Dental wear caused by association between bruxism and gastroesophageal reflux disease: a rehabilitation report.

Science.gov (United States)

Machado, Naila Aparecida de Godoi; Fonseca, Rodrigo Borges; Branco, Carolina Assaf; Barbosa, Gustavo Augusto Seabra; Fernandes Neto, Alfredo Júlio; Soares, Carlos José

2007-08-01

Bruxism is a pathological activity of the stomatognathic system that involves tooth grinding and clenching during parafunctional jaw movements. Clinical signs of bruxism are mostly related to dental wear and muscular and joint discomforts, but a large number of etiological factors can be listed, as local, systemic, psychological and hereditary factors. The association between bruxism, feeding and smoking habits and digestive disorders may lead to serious consequences to dental and related structures, involving dental alterations (wear, fractures and cracks), periodontal signs (gingival recession and tooth mobility) and muscle-joint sensitivity, demanding a multidisciplinary treatment plan. This paper presents a case report in which bruxism associated with acid feeding, smoking habit and episodes of gastric reflow caused severe tooth wear and great muscular discomfort with daily headache episodes. From the diagnosis, a multidisciplinary treatment plan was established. The initial treatment approach consisted of medical follow up with counseling on diet and smoking habits and management of the gastric disorders. This was followed by the installation of an interocclusal acrylic device in centric relation of occlusion (CRO) for reestablishment of the occlusal stability, vertical dimension of occlusion, anterior guides and return to normal muscle activity (90-day use approximately). After remission of initial symptoms, oral rehabilitation was implemented in CRO by means of full resin composite restorations and new interocclusal device for protection of restorations. Satisfactory esthetics, improved function and occlusal stability were obtained after oral rehabilitation. The patient has attended annual follow-ups for the past 2 years. The multidisciplinary treatment seems to be the key for a successful rehabilitation of severe cases of dental wear involving the association of different health disorders.

Staging workers' use of hearing protection devices: application of the transtheoretical model.

Science.gov (United States)

Raymond, Delbert M; Lusk, Sally L

2006-04-01

The threat of noise-induced hearing loss is a serious concern for many workers. This study explores use of the transtheoretical model as a framework for defining stages of workers' acceptance of hearing protection devices. A secondary analysis was performed using a cross-section of data from a randomized, controlled clinical trial of an intervention to increase use of hearing protection. Use of hearing protection devices was well distributed across the theorized stages of change. Chi-square analysis and analysis of variance revealed significant differences between stages for the variables studied. Discrete stages of hearing protection device use can be identified, laying the foundation for further work investigating use of the transtheoretical model for promoting hearing protection device use. The model can provide a framework for tailoring interventions and evaluating their effects. With further development of the transtheoretical model, nurses may be able to easily identify workers' readiness to use hearing protection devices and tailor training toward that goal.

Novel material and structural design for large-scale marine protective devices

International Nuclear Information System (INIS)

Qiu, Ang; Lin, Wei; Ma, Yong; Zhao, Chengbi; Tang, Youhong

2015-01-01

Highlights: • Large-scale protective devices with different structural designs have been optimized. • Large-scale protective devices with novel material designs have been optimized. • Protective devices constructed of sandwich panels have the best anti-collision performance. • Protective devices with novel material design can reduce weight and construction cost. - Abstract: Large-scale protective devices must endure the impact of severe forces, large structural deformation, the increased stress and strain rate effects, and multiple coupling effects. In evaluation of the safety of conceptual design through simulation, several key parameters considered in this research are maximum impact force, energy dissipated by the impactor (e.g. a ship) and energy absorbed by the device and the impactor stroke. During impact, the main function of the ring beam structure is to resist and buffer the impact force between ship and bridge pile caps, which could guarantee that the magnitude of impact force meets the corresponding requirements. The means of improving anti-collision performance can be to increase the strength of the beam section or to exchange the steel material with novel fiber reinforced polymer laminates. The main function of the buoyancy tank is to absorb and transfer the ship’s kinetic energy through large plastic deformation, damage, or friction occurring within itself. The energy absorption effect can be improved by structure optimization or by the use of new sandwich panels. Structural and material optimization schemes are proposed on the basis of conceptual design in this research, and protective devices constructed of sandwich panels prove to have the best anti-collision performance

Evaluation of Extended-Wear Hearing Technology for Children with Hearing Loss.

Science.gov (United States)

Wolfe, Jace; Schafer, Erin; Martella, Natalie; Morais, Mila; Mann, Misty

2015-01-01

Research shows that many older children and teenagers who have mild to moderately severe sensorineural hearing loss do not use their hearing instruments during all waking hours. A variety of reasons may contribute toward this problem, including concerns about cosmetics associated with hearing aid use and the inconvenience of daily maintenance associated with hearing instruments. Extended-wear hearing instruments are inserted into the wearer's ear canal by an audiologist and are essentially invisible to outside observers. The goal of this study was to evaluate the potential benefits and limitations associated with use of extended-wear hearing instruments in a group of children with hearing loss. A two-way repeated measures design was used to examine performance differences obtained with the participants' daily-wear hearing instruments versus that obtained with extended-wear hearing instruments. Sixteen children, ages 10-17 yr old, with sensorineural hearing loss ranging from mild to moderately severe. Probe microphone measures were completed to evaluate the aided output of device. Behavioral test measures included word recognition in quiet, sentence recognition in noise, aided warble-tone thresholds, and psychophysical loudness scaling. Questionnaires were also administered to evaluate subjective performance with each hearing technology. Data logging suggested that many participants were not using their daily-wear hearing instruments during all waking hours (mean use was less than 6 h/day). Real ear probe microphone measurements indicated that a closer fit to the Desired Sensation Level Version 5 prescriptive targets was achieved with the children's daily-wear instruments when compared to the extended-wear instruments. There was no statistically significant difference in monosyllabic word recognition at 50 or 60 dBA obtained with the two hearing technologies. Sentence recognition in noise obtained with use of the extended-wear devices was, however, significantly

Tooth wear and wear investigations in dentistry.

Science.gov (United States)

Lee, A; He, L H; Lyons, K; Swain, M V

2012-03-01

Tooth wear has been recognised as a major problem in dentistry. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Although the dental literature contains numerous publications related to management and rehabilitation of tooth wear of varying aetiologies, our understanding of the aetiology and pathogenesis of tooth wear is still limited. The wear behaviour of dental biomaterials has also been extensively researched to improve our understanding of the underlying mechanisms and for the development of restorative materials with good wear resistance. The complex nature of tooth wear indicates challenges for conducting in vitro and in vivo wear investigations and a clear correlation between in vitro and in vivo data has not been established. The objective was to critically review the peer reviewed English-language literature pertaining to prevalence and aetiology of tooth wear and wear investigations in dentistry identified through a Medline search engine combined with hand-searching of the relevant literature, covering the period between 1960 and 2011. © 2011 Blackwell Publishing Ltd.

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.

14 CFR 25.1357 - Circuit protective devices.

Science.gov (United States)

2010-01-01

... system or connected equipment. (b) The protective and control devices in the generating system must be designed to de-energize and disconnect faulty power sources and power transmission equipment from their...

Bio-inspired polymeric patterns with enhanced wear durability for microsystem applications

International Nuclear Information System (INIS)

Singh, R. Arvind; Siyuan, L.; Satyanarayana, N.; Kustandi, T.S.; Sinha, Sujeet K.

2011-01-01

At micro/nano-scale, friction force dominates at the interface between bodies moving in relative motion and severely affects their smooth operation. This effect limits the performance of microsystem devices such as micro-electro-mechanical systems (MEMS). In addition, friction force also leads to material removal or wear and thereby reduces the durability i.e. the useful operating life of the devices. In this work, we fabricated bio-inspired polymeric patterns for tribological applications. Inspired by the surface features on lotus leaves namely, the protuberances and wax, SU-8 polymeric films spin-coated on silicon wafers were topographically and chemically modified. For topographical modification, micro-scale patterns were fabricated using nanoimprint lithography and for chemical modification, the micro-patterns were coated with perfluoropolyether nanolubricant. Tribological investigation of the bio-inspired patterns revealed that the friction coefficients reduced significantly and the wear durability increased by several orders. In order to enhance the wear durability much further, the micro-patterns were exposed to argon/oxygen plasma and were subsequently coated with the perfluoropolyether nanolubricant. Bio-inspired patterns with enhanced wear durability, such as the ones investigated in the current work, have potential tribological applications in MEMS/Bio-MEMS actuator-based devices. Highlights: →Bio-inspired polymeric patterns for tribological applications in microsystems. →Novel surface modification for the patterns to enhance tribological properties. →Patterns show low friction properties and extremely high wear durability.

14 CFR 29.1357 - Circuit protective devices.

Science.gov (United States)

2010-01-01

... faults or serious malfunction of the system or connected equipment. (b) The protective and control devices in the generating system must be designed to de-energize and disconnect faulty power sources and...

Modeling of Wear of Knives of Paper-Cutting Machines in Use

OpenAIRE

Кулак, Михаил Иосифович; Медяк, Диана Михайловна

2016-01-01

Development of the theory of cutting of paper and methods of measurement of width of the cutting edge in the course of wear of a knife is analyzed. Device to a micrometer for measurement of the tool edge width and a way of determination of radius of a curve of the cutting edge of such tool is presented. The card of wear of a knife is constructed and process of wear of the self-sharpened knife is investigated.

Single-crystal-silicon-based microinstrument to study friction and wear at MEMS sidewall interfaces

International Nuclear Information System (INIS)

Ansari, N; Ashurst, W R

2012-01-01

Since the advent of microelectromechanical systems (MEMS) technology, friction and wear are considered as key factors that determine the lifetime and reliability of MEMS devices that contain contacting interfaces. However, to date, our knowledge of the mechanisms that govern friction and wear in MEMS is insufficient. Therefore, systematically investigating friction and wear at MEMS scale is critical for the commercial success of many potential MEMS devices. Specifically, since many emerging MEMS devices contain more sidewall interfaces, which are topographically and chemically different from in-plane interfaces, studying the friction and wear characteristics of MEMS sidewall surfaces is important. The microinstruments that have been used to date to investigate the friction and wear characteristics of MEMS sidewall surfaces possess several limitations induced either by their design or the structural film used to fabricate them. Therefore, in this paper, we report on a single-crystal-silicon-based microinstrument to study the frictional and wear behavior of MEMS sidewalls, which not only addresses some of the limitations of other microinstruments but is also easy to fabricate. The design, modeling and fabrication of the microinstrument are described in this paper. Additionally, the coefficients of static and dynamic friction of octadecyltrichlorosilane-coated sidewall surfaces as well as sidewall surfaces with only native oxide on them are also reported in this paper. (paper)

Wear behavior of pressable lithium disilicate glass ceramic.

Science.gov (United States)

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

2016-07-01

This article reports effects of surface preparation and contact loads on abrasive wear properties of highly aesthetic and high-strength pressable 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 three-dimensional 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 behavior of LDGC and will provide guidelines for better utilization and preparation of the material for long-term success in dental restorations. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 968-978, 2016. © 2015 Wiley Periodicals, Inc.

Dependable Design Flow for Protection Systems using Programmable Logic Devices

CERN Document Server

Kwiatkowski, M

2011-01-01

Programmable Logic Devices (PLD) such as Field Programmable Gate Arrays (FPGA) are becoming more prevalent in protection and safety-related electronic systems. When employing such programmable logic devices, extra care and attention needs to be taken. The final synthesis result, used to generate the bit-stream to program the device, must be shown to meet the design’s requirements. This paper describes how to maximize confidence using techniques such as Formal Methods, exhaustive Hardware Description Language (HDL) code simulation and hardware testing. An example is given for one of the critical functions of the Safe Machine Parameters (SMP) system, used in the protection of the Large Hadron Collider (LHC) at CERN. CERN is also working towards an adaptation of the IEC- 61508 lifecycle designed for Machine Protection Systems (MPS), and the High Energy Physics environment, implementation of a protection function in FPGA code is only one small step of this lifecycle. The ultimate aim of this project is to cre...

Efficiency and safety of percuSurge distal protection device in acute ...

African Journals Online (AJOL)

user

2011-04-25

Apr 25, 2011 ... myocardial infarction. The long-term effects of the distal protection device are still in controversy. The enhanced myocardial efficacy and recovery by aspiration of liberated debris (EMERALD) trial failed to show the effectiveness of the distal protection device in patients with AMI (Yamada and Topol, 2000).

Impact Fretting Wear Behavior of Alloy 690 Tubes in Dry and Deionized Water Conditions

Institute of Scientific and Technical Information of China (English)

Zhen-Bing Cai; Jin-Fang Peng; Hao Qian; Li-Chen Tang; Min-Hao Zhu

2017-01-01

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.

Analysis of emboli during carotid stenting with distal protection device.

Science.gov (United States)

Chen, Chin-I; Iguchi, Yasuyuki; Garami, Zsolt; Malkoff, Marc D; Smalling, Richard W; Campbell, Morgan S; Alexandrov, Andrei V

2006-01-01

The newly developed multi-frequency transcranial Doppler (TCD) is able to differentiate gaseous from solid emboli. Our goal was to apply this technology to initially characterize emboli detected during carotid stenting with distal protection. Patients undergoing carotid angiography and stenting were monitored with 2-2.5 MHz TCD (Embo-Dop, DWL) over the middle cerebral artery unilateral to stent deployment. Sonographers insured optimal signal recordings during the procedures. Automated emboli detection and classification software (MultiXLab version 2.0) was applied for offline count and analysis. Monitoring using the Filter Wire EX (Boston Scientific) and ACCUNET system (Guidant Corporation) was performed. A total of 9,649 embolic signals were detected during 11 angiographic and 10 stenting procedures. An observer confirmed the signals using the International Consensus definition. Automated software classified these events into 5,900 gaseous and 3,749 solid emboli. During contrast injections without the protection device, 1,013 emboli were detected with 28% of these being solid. With deployment of the distal protection device, 8,636 emboli were found with 40% being solid (p protection device, 7,395 emboli with 42% solids were detected (p protection device still deployed, yielded 1,241 emboli with 31% solids (NS). Only 1 patient developed transient hemiparesthesia during ballooning that reduced the flow velocity to zero for 14 s. Neither gaseous nor solid emboli resulted in a mean flow velocity decrease or clinical symptoms. Microembolization frequently occurs during stenting even with deployment of the distal protection device. More solid emboli are seen during manipulations associated with lesion crossing. Although novel TCD methods yield a high frequency of embolic signals, further validation of this technique to determine the true nature, size, and number of emboli is needed.

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.

Wear studies of engine components using neutron activation techniques

International Nuclear Information System (INIS)

Banados Perez, H.E.; Carvalho, G.; Daltro, T.F.L.

1984-01-01

The results obtained in a series of tests for determining the wearing rate of some diesel engine components are reported. The pieces investigated were the needles of fuel injection nozzles, that were previously irradiated with a 10 13 nv in the IEA-R1 nuclear reactor, and the wearing rate was established for different types of fuels. Total wear was calculated by measuring the specific activity of 51 Cr present in the fuel and originated by metal particles worn from the needle. Wear were performed using a device that simulated the actual working conditions of the injection nozzles. The system was run during 350 hours and, along that period, 36 fuel samples of 10 ml each, were collected and analysed for cumulative wear calculation. A metal concentration as low as 10- 6 g in 10 ml of fuel sample could be measured by this method. At present time this procedure is being applied for measuring the wear-rate of other nozzle parts, using localized neutron activation techiques. (Author) [pt

Protective Effect of Adhesive Systems associated with Neodymium-doped Yttrium Aluminum Garnet Laser on Enamel Erosive/Abrasive Wear.

Science.gov (United States)

Crastechini, Erica; Borges, Alessandra B; Becker, Klaus; Attin, Thomas; Torres, Carlos Rg

2017-10-01

This study evaluated the efficacy of self-etching adhesive systems associated or not associated with the neodymium-doped yttrium aluminum garnet (Nd:YAG) laser on the protection against enamel erosive/abrasive wear. Bovine enamel specimens were demineralized with 0.3% citric acid (5 minutes). The samples were randomly assigned to eight groups (n = 20): SB - Single Bond Universal (3M/ESPE); SB+L - Single Bond Universal + laser (80 mJ/10 Hz); FB - Futurabond U (Voco); FB+L -Futurabond U + laser; GEN - G-aenial bond (GC); GEN+L -G-aenial bond + laser; L - laser irradiation; and C - no treatment. The laser was applied before light curing. The samples were subjected to erosive/abrasive challenges (0.3% citric acid - 2 minutes and tooth brushing four times daily for 5 days). Enamel surface loss was recovered profilometrically by comparison of baseline and final profiles. The adhesive layer thickness, retention percentage of the protective layer, and microhardness of cured adhesive were measured. Data were analyzed using one-way analysis of variance and Tukey's test (5%). There were significant differences for all parameters (p = 0.0001). Mean values ± SD and results of the Tukey's test were: Surface wear: GEN - 4.88 (±1.09)a, L - 5.04 ± 0.99)a, FB - 5.32 (±0.93)ab, GEN + L - 5.46 (±1.27)abc, SB + L - 5.78 (±1.12)abc, FB + L - 6.23 (±1.25)bc, SB - 6.35 (±1.11)c, and C - 6.46 (±0.61)c; layer thickness: GEN - 15.2 (±8.63)c, FB - 5.06 (±1.96)a, GEN + L - 13.96 (±7.07)bc, SB + L - 4.24 (±2.68)a, FB + L - 9.03 (±13.02)abc, and SB - 7.49 (±2.80)ab; retention: GEN - 68.89 (±20.62)c, FB - 54.53 (±24.80)abc, GEN + L - 59.90 (±19.79)abc, SB + L - 63.37 (±19.30)bc, FB + L - 42.23 (±17.68) a, and SB - 47.78 (±18.29)ab; microhardness: GEN - 9.27 (±1.75)c; FB - 6.99 (±0.89)b; GEN + L - 6.22 (±0.87)ab; SB + L - 15.48 (±2.51)d; FB + L - 10.67 (±1.58)c; SB - 5.00 (±1.60)a. The application of Futurabond U and G-aenial bond on enamel surface, as well as the Nd

Estimation of digital protection devices applicability on basis of multiple characterizing parameters

Directory of Open Access Journals (Sweden)

Dimitar Bogdanov

2018-01-01

Full Text Available The contemporary electrical power systems (EPS impose increased requirements for the functionality of the protection systems. The necessity of improved EPS stability is in some extent resulting of the increased integration of renewable sources of electrical energy. The future grid development gives perspective for connection of more converter based generations. The power electronic schemes and associated functional requirements impose necessity of high speed, sensitive, selective and reliable operation of the protection devices. These requirements have always been target of the protection equipment producers and grid operators. The electronic converting schemes specifics impose these requirements for the protection devices in more straightened way, as the converter connected generator may need to trip in shorter time than classical machine generator. In the article is presented a generalized overview of some of the characteristics of the digital “relay” protection devices, and approach for device selection is proposed. Investment planning may utilize such approach in order to have an optimal design from financial point of view.

The use of hearing protection devices by older adults during recreational noise exposure.

Science.gov (United States)

Nondahl, D M; Cruickshanks, K J; Dalton, D S; Klein, B E K; Klein, R; Tweed, T S; Wiley, T L

2006-01-01

A population-based study to assess the use of hearing protection devices by older adults during noisy recreational activities was performed. The population-based Epidemiology of Hearing Loss Study was designed to measure the prevalence of hearing loss in adults residing in Beaver Dam, Wisconsin. The use of hearing protection devices during noisy recreational activities was assessed by performing three examinations over a period of 10 years (1993-1995, no. of participants (n)=3753, aged 48-92 years; 1998-2000, n=2800, aged 53-97 years; 2003-2005, n=2395, aged 58-100 years). The recreational activities included hunting, target shooting, woodworking/carpentry, metalworking, driving loud recreational vehicles, and performing yard work using either power tools or a chain saw. The prevalence of using hearing protection devices during any of these activities increased with time (9.5%, 15.0%, and 19.9% at baseline, 5 years, and 10 years, respectively). However, the use of hearing protection devices remained low for most activities. Those under the age of 65 were twice as likely to use hearing protection devices during noisy activities than were older adults. Men, those with a hearing handicap, and those with significant tinnitus were more likely to use hearing protection devices. Smokers and the less educated were less likely to use hearing protection devices. The results demonstrated that many adults expose themselves to potentially damaging recreational noise, leaving them at risk for hearing loss.

30 CFR 75.1723 - Stationary grinding machines; protective devices.

Science.gov (United States)

2010-07-01

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

Consumer protection issues in energy: a guide for attorneys general. Insulation, solar, automobile device, home devices

Energy Technology Data Exchange (ETDEWEB)

Cohen, Harry I.; Hulse, William S.; Jones, Robert R.; Langer, Robert M.; Petrucelli, Paul J.; Schroeder, Robert J.

1979-11-01

The guide attempts to bring together two important and current issues: energy and consumer protection. Perhaps the most basic consumer-protection issue in the energy area is assuring adequate supplies at adequate prices. It is anticipated, though, that consumers will want to consider new ways to lower enegy consumption and cost, and will thus be susceptible to fraudulent energy claims. Information is prepared on insulation, solar, energy-saving devices for the home, and energy-saving devices for the automobile.

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

OpenAIRE

Fadhel Abbas. Abdulla; Katea L. Hamid

2017-01-01

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 di...

30 CFR 77.401 - Stationary grinding machines; protective devices.

Science.gov (United States)

2010-07-01

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

The radiation protective devices for interventional procedures using computed tomography

International Nuclear Information System (INIS)

Iida, Hiroji; Chabatake, Mitsuhiro; Shimizu, Mitsuru; Tamura, Sakio

2002-01-01

A scattered dose and a surface dose from phantom measurements during interventional procedures with computed tomography (IVR-CT) were evaluated. To reduce the personnel exposure in IVR-CT, the new protective devices were developed and its effect evaluated. Two radiation protection devices were experimentally made using a lead vinyl sheet with lead equivalent 0.125 mmPb. The first device is a lead curtain which shields the space of CT-gantry and phantom for the CT examination. The second device is a lead drape which shields on the phantom surface adjacent to the scanning plane for the CT-fluoroscopy. Scattered dose and phantom surface dose were measured with an abdominal phantom during Cine-CT (130 kV, 150 mA, 5 seconds, 10 mm section thickness). They were measured by using ionization chamber dosimeter. They were measured with and without a lead curtain and a lead drape. Scattered dose rate was measured at distance of 50-150 cm from the scanning plane. And, surface dose was measured at distance of 4-21 cm from the scanning plane on the phantom. On operator's standing position, scattered dose rates were from 8.4 to 11.6 μGy/sec at CT examination. The lead curtain and the lead drape reduced scattered dose rate at distance of 50 cm from the scanning plane by 66% and 58.3% respectively. Surface dose rate were 118 μGy/sec at distance of 5 cm from the scanning plane at CT-fluoroscopy. The lead drape reduced the surface dose by 60.5%. High scattered exposure to personnel may occur during interventional procedures using CT. They were considerably reduced during CT-arteriography by attaching the lead curtain in CT equipment. And they were substantially reduced during CT-fluoroscopy by placing the lead drape adjacent to the scanning plane, in addition, operator's hand would be protected from unnecessary radiation scattered by phantom. It was suggested that the scattered exposure to personnel could be sufficiently reduced by using radiation protection devices in IVR-CT. The

Skin sites to predict deep-body temperature while wearing firefighters' personal protective equipment during periodical changes in air temperature.

Science.gov (United States)

Kim, Siyeon; Lee, Joo-Young

2016-04-01

The aim of this study was to investigate stable and valid measurement sites of skin temperatures as a non-invasive variable to predict deep-body temperature while wearing firefighters' personal protective equipment (PPE) during air temperature changes. Eight male firefighters participated in an experiment which consisted of 60-min exercise and 10-min recovery while wearing PPE without self-contained breathing apparatus (7.75 kg in total PPE mass). Air temperature was periodically fluctuated from 29.5 to 35.5 °C with an amplitude of 6 °C. Rectal temperature was chosen as a deep-body temperature, and 12 skin temperatures were recorded. The results showed that the forehead and chest were identified as the most valid sites to predict rectal temperature (R(2) = 0.826 and 0.824, respectively) in an environment with periodically fluctuated air temperatures. This study suggests that particular skin temperatures are valid as a non-invasive variable when predicting rectal temperature of an individual wearing PPE in changing ambient temperatures. Practitioner Summary: This study should offer assistance for developing a more reliable indirect indicating system of individual heat strain for firefighters in real time, which can be used practically as a precaution of firefighters' heat-related illness and utilised along with physiological monitoring.

Adjustable radiation protection device of the fluoroscope DG 10

International Nuclear Information System (INIS)

Hoermann, D.

1980-01-01

In cooperation with the 'VEB Transformatoren- und Roentgenwerk Hermann Matern', Dresden, an adjustable radiation protection device has been developed. This supplementary equipment for fluoroscopes ensures a sufficient protection of the gonads against undesirable X radiation, can be handled easily and does not annoy patients, esp. children

Developing biomedical devices design, innovation and protection

CERN Document Server

Andreoni, Giuseppe; Colombo, Barbara

2013-01-01

During the past two decades incredible progress has been achieved in the instruments and devices used in the biomedical field. This progress stems from continuous scientific research that has taken advantage of many findings and advances in technology made available by universities and industry. Innovation is the key word, and in this context legal protection and intellectual property rights (IPR) are of crucial importance. This book provides students and practitioners with the fundamentals for designing biomedical devices and explains basic design principles. Furthermore, as an aid to the dev

Physical limitations of semiconductor devices defects, reliability and esd protection

CERN Document Server

Vashchenko, V A

2008-01-01

Provides an important link between the theoretical knowledge in the field of non-linier physics and practical application problems in microelectronics. This title focuses on power semiconductor devices and self-triggering pulsed power devices for ESD protection clamps.

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...

Protective device for organs exposed to medical X-radiation

International Nuclear Information System (INIS)

Zimmer, K.

1978-01-01

The protective device for male or female gonads consists of a protective screen made of hard lead coated with silicon caoutchouc, a flexible supporting arm, and a base plate on which the supporting arm for the protective screen is monted. The protective screen has got the shape of a dish resp. a pear-shaped contour for male resp. female persons. The base may be arranged on a Bucky table between the legs of the person to be examined by means of suction cups. (DG) [de

The safety and efficacy of contact lens wear in the industrial and chemical workplace.

Science.gov (United States)

Tyhurst, Keith; McNett, Ryan; Bennett, Edward

2007-11-01

The use and safety of contact lenses in the industrial and chemical workplace has often been questioned since the 1960s because of many unconfirmed reports of ocular injury resulting from contact lens wear. Because of these urban legends, contact lens wear has been banned or wearers have been required to wear additional personal protective equipment (PPE) not required of non-contact lens wearers. Literature review via Medline and Google search. Research has shown that contact lenses typically provide protective benefits that decrease the severity of ocular injury and improve worker performance. While contact lens wear contraindications do exist, in most cases, and with proper precautions, contact lens wear is still possible. Industrial and chemical companies need to establish written contact lens use policies based on current studies that have shown the safety of workplace contact lens wear when combined with the same PPE required of non-contact lens wearers. Practitioners need to discuss, with their contact lens patients, the additional responsibilities required to maintain proper lens hygiene and proper PPE in the workplace.

Investigation of surge protective devices operation of a wind generator

International Nuclear Information System (INIS)

Dimitrov, D.; Vasileva, M.

2008-01-01

The interest to the investments in a wind energetics increases in the last years. The wind energetics is the fastest developing direction in the energetics in global scale. The wind energy is more attractive because its prices are lower in comparison of the other technologies for generating energy. The right choice of the surge protective devices has the important meaning on building and exploitation of the wind generators. The aim of this paper is investigation of the surge protective devices operation when they are installation to a wind generator. (authors)

Isotopic study of the wear of sliding bearings with plastic friction surface

International Nuclear Information System (INIS)

Pandur, J.; Varkonyi, A.

1978-01-01

A new complex device has been elaborated for the investigation of the duration of bearings in the Institute of Isotopes of the Hungarian Academy of Sciences. The simultaneous determination of wear by an isotopic method the coefficient of friction by means of a Wheatstone bridge and the bearing temperature by means of a thermoresistor is described. Dynamic loading and variable revolution per minute are applied to produce a forced wear of the bearings. The isotopically labelled wear products are removed by oil and the collected sample is measured by a scintillation detector. Wear of a steel axle in plastic housing and plastic coated axle in cast iron housing was determined. (V.N.)

Turbine protecting device in a BWR type nuclear power plant

International Nuclear Information System (INIS)

Kasuga, Hajime; Oka, Yoko.

1984-01-01

Purpose: To prevent highly humid steams from flowing into the turbine upon abnormal reduction in the reactor water level in order to ensure the turbine soundness, as well as in order to trip the turbine with no undesired effect on the reactor. Constitution: A protection device comprising a judging device and a timer are disposed in a BWR type reactor, in order to control a water level signal from a reactor water level gage. If the reactor water level is reduced during rated power operation, steams are kept to be generated due to decay heat although reactor is scramed. When a signal from the reactor water level detector is inputted to the protection device, a trip signal is outputted by way of a judging device after 15 second by means of the timer, when the main steam check valve is closed to trip the turbine. With this delay of time, abrupt increase in the pressure of the reactor due to sudden shutdown can be prevented. (Nakamoto, H)

30 CFR 77.600 - Trailing cables; short-circuit protection; disconnecting devices.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trailing cables; short-circuit protection... AREAS OF UNDERGROUND COAL MINES Trailing Cables § 77.600 Trailing cables; short-circuit protection; disconnecting devices. Short-circuit protection for trailing cables shall be provided by an automatic circuit...

Related factors to workers' use of hearing protection device in knitting & ppinning factories of Yazd city based on Protection Motivation Theory

Directory of Open Access Journals (Sweden)

A. Barkhordi

2009-10-01

Full Text Available Background and aimsNoise-Induced Hearing Loss (NIHL is an important occupational disorder. High percentage of workers in occupational environments did not use the hearing protection device against harmful noise. This study was carried out to study factors related to workers' use of Hearing protection Device in Knitting & spinning factories of Yazd city based on protection motivation theory.MethodsIn this cross-sectional analytical study 280 workers of the knitting & spinning factories of Yazd City who exposed to harmful noise (over 85dB selected among the three factories by cluster sampling. The data gathered via exclusive interviews with selected workers  using the questionnaire designed based on protection motivation theory and were analyzedResults42/5 percent of workers permanently used hearing protection devices, and 20/7 percent of workers never use.There was a significant correlation between the age of workers and the mean score components of PMT; perceived severity, perceived vulnerability, perceived response efficacy and protection motivation. There was also a significant correlation between the work experience and the mean score of PMT factors; perceived severity, perceived response efficacy and perceived vulnerability. Also there was a significant correlation between workers' education level and the mean score of perceived response efficacy and there was a significant correlation between protection motivation and the mean score components of PMT; perceived vulnerability, perceived self-efficacy, perceived response efficacy, perceived costs and behaviorConclusionRegarding the significant correlations between the more constructs of PMT and protection motivation of workers for using hearing protective device, designing educational program based on PMT to increase hearing protection devices usage among workers is recommended.

Comparison of friction and wear of articular cartilage on different length scales.

Science.gov (United States)

Kienle, Sandra; Boettcher, Kathrin; Wiegleb, Lorenz; Urban, Joanna; Burgkart, Rainer; Lieleg, Oliver; Hugel, Thorsten

2015-09-18

The exceptional tribological properties of articular cartilage are still far from being fully understood. Articular cartilage is able to withstand high loads and provide exceptionally low friction. Although the regeneration abilities of the tissue are very limited, it can last for many decades. These biomechanical properties are realized by an interplay of different lubrication and wear protection mechanisms. The deterioration of cartilage due to aging or injury leads to the development of osteoarthritis. A current treatment strategy focuses on supplementing the intra-articular fluid with a saline solution containing hyaluronic acid. In the work presented here, we investigated how changing the lubricating fluid affects friction and wear of articular cartilage, focusing on the boundary and mixed lubrication as well as interstitial fluid pressurization mechanisms. Different length and time scales were probed by atomic force microscopy, tribology and profilometry. We compared aqueous solutions with different NaCl concentrations to a viscosupplement containing hyaluronic acid (HA). In particular, we found that the presence of ions changes the frictional behavior and the wear resistance. In contrast, hyaluronic acid showed no significant impact on the friction coefficient, but considerably reduced wear. This study confirms the previous notion that friction and wear are not necessarily correlated in articular cartilage tribology and that the main role of HA might be to provide wear protection for the articular surface. Copyright © 2015 Elsevier Ltd. All rights reserved.

UV radiation sources for artificial skin tanning and protection

International Nuclear Information System (INIS)

Zivkovic, D.; Hrnjak, M.

1999-01-01

UV radiation sources for artificial tanning are more utilized at the last time. UV radiation is not harmless, so there are not safety devices for tanning. If people do not want to avoid exposure to their radiation, than it is necessary to take the prevention measure: strictly dose of UV radiation according to skin type, use of appropriate protective eye-wears and respect for inhibit of some medicaments and some cosmetic products use. (author)

Preventive protection device and method for bottom of reactor pressure vessel

International Nuclear Information System (INIS)

Hayashi, Eisaku; Kurosawa, Koichi; Furukawa, Hideyasu; Morinaka, Ren; Enomoto, Kunio; Otaka, Masahiro; Yoshikubo, Fujio; Chiba, Noboru; Sato, Kazunori.

1995-01-01

In a preventive protection device for improving stresses in reactor structural components by jetting highly pressurized water with cavitation bubbles from a jetting nozzle toward structural components in a reactor pressure vessel, a fixed structure to a CRD housing is provided with a rotational body attached to the structure, a multi joint arm and a jetting nozzle supported to the multi joint arm. The jetting nozzle is disposed at a position where the center of the jetting deviates from the center of the CRD housing. In addition, a monitoring camera is disposed for displaying the target for preventive protection. The state of stresses on a plurality of targets for preventive protection can be improved by the preventive protection device at a fixed position in the bottom of a reactor pressure vessel where housings stand densely, thereby enabling to attain the preventive protection operation easily and rapidly. (N.H.)

Performance evaluation of thin wearing courses through scaled accelerated trafficking.

Science.gov (United States)

2014-01-01

The primary objective of this study was to evaluate the permanent deformation (rutting) and fatigue performance of : several thin asphalt concrete wearing courses using a scaled-down accelerated pavement testing device. The accelerated testing : was ...

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.

Enhancement of Engine Oil Wear and Friction Control Performance Through Titanium Additive Chemistry

International Nuclear Information System (INIS)

Guevremont, J.; Guinther, G.; Szemenyei, D.; Devlin, M.; Jao, T.; Jaye, C.; Woicik, J.; Fischer, D.

2008-01-01

Traditionally, wear protection and friction modification by engine oil is provided by zinc dithiophosphate (ZDDP) or other phosphorus compounds. These additives provide effective wear protection and friction control on engine parts through formation of a glassy polyphosphate antiwear film. However, the deposition of phosphorus species on automotive catalytic converters from lubricants has been known for some time to have a detrimental effect of poisoning the catalysts. To mitigate the situation, the industry has been making every effort to find ZDDP-replacement additives that are friendly to catalysts. Toward this goal we have investigated a titanium additive chemistry as a ZDDP replacement. Fully formulated engine oils incorporating this additive component have been found to be effective in reducing wear and controlling friction in a high-frequency reciprocating rig (HFRR), 4-ball bench wear, Sequence IIIG, and Sequence IVA engine tests. Surface analysis of the tested parts by Auger electron spectroscopy, secondary ion mass spectrometry (SIMS), and X-ray photoelectron spectroscopy (XPS) have shown that Ti species have been incorporated into the wear tracks and can only be found on the wear tracks. We used synchrotron based near edge X-ray absorption fine structure (NEXAFS) to investigate the chemical bonding mechanism of the Ti additive with the metal surface that affects the wear improvement mechanism. We postulate that Ti provides antiwear enhancement through inclusion in the metal/metal oxide structure of the ferrous surface by forming FeTiO3.

Gender and other factors associated with the use of hearing protection devices at work

Directory of Open Access Journals (Sweden)

Tatiane Costa Meira

2015-01-01

Full Text Available OBJECTIVE To analyze whether sociodemographic, occupational, and health-related data are associated with the use of hearing protection devices at work, according to gender.METHODS A cross-sectional study was conducted in 2006, using a random sample of 2,429 workers, aged between 18 and 65 years old, from residential sub-areas in Salvador, BA, Northeastern Brazil. Questionnaires were used to obtain sociodemographic, occupational, and health-related data. Workers who reported that they worked in places where they needed to shout in order to be heard were considered to be exposed to noise. Exposed workers were asked whether they used hearing protection devices, and if so, how frequently. Analyses were conducted according to gender, with estimates made about prevalence of the use of hearing protection devices, prevalence ratios, and their respective 95% confidence intervals.RESULTS Twelve percent (12.3% of study subjects reported that they were exposed to noise while working. Prevalence of the use of hearing protection devices was 59.3% for men and 21.4% for women. Men from higher socioeconomic levels (PR = 1.47; 95%CI 1.14;1.90 and who had previous audiometric tests (PR = 1.47; 95%CI 1.15;1.88 were more likely to use hearing protection devices. For women, greater perceived safety was associated with the use of protection devices (PR = 2.92; 95%CI 1.34;6.34. This perception was specifically related to the presence of supervisors committed to safety (PR = 2.09; 95%CI 1.04;4.21, the existence of clear rules to prevent workplace injuries (PR = 2.81; 95%CI 1.41;5.59, and whether they were informed about workplace safety (PR = 2.42; 95%CI 1.23;4.76.CONCLUSIONS There is a gender bias regarding the use of hearing protection devices that is less favorable to women. The use of such devices among women is positively influenced by their perception of a safe workplace, suggesting that gender should be considered as a factor in hearing conservation programs.

Ultra-high wear resistance of ultra-nanocrystalline diamond film: Correlation with microstructure and morphology

Science.gov (United States)

Rani, R.; Kumar, N.; Lin, I.-Nan

2016-05-01

Nanostructured diamond films are having numerous unique properties including superior tribological behavior which is promising for enhancing energy efficiency and life time of the sliding devices. High wear resistance is the principal criterion for the smooth functioning of any sliding device. Such properties are achievable by tailoring the grain size and grain boundary volume fraction in nanodiamond film. Ultra-nanocrystalline diamond (UNCD) film was attainable using optimized gas plasma condition in a microwave plasma enhanced chemical vapor deposition (MPECVD) system. Crystalline phase of ultra-nanodiamond grains with matrix phase of amorphous carbon and short range ordered graphite are encapsulated in nanowire shaped morphology. Film showed ultra-high wear resistance and frictional stability in micro-tribological contact conditions. The negligible wear of film at the beginning of the tribological contact was later transformed into the wearless regime for prolonged sliding cycles. Both surface roughness and high contact stress were the main reasons of wear at the beginning of sliding cycles. However, the interface gets smoothened due to continuous sliding, finally leaded to the wearless regime.

Preferential superior surface motion in wear simulations of the Charité total disc replacement.

Science.gov (United States)

Goreham-Voss, Curtis M; Vicars, Rachel; Hall, Richard M; Brown, Thomas D

2012-06-01

Laboratory wear simulations of the dual-bearing surface Charité total disc replacement (TDR) are complicated by the non-specificity of the device's center of rotation (CoR). Previous studies have suggested that articulation of the Charité preferentially occurs at the superior-bearing surface, although it is not clear how sensitive this phenomenon is to lubrication conditions or CoR location. In this study, a computational wear model is used to study the articulation kinematics and wear of the Charité TDR. Implant wear was found to be insensitive to the CoR location, although seemingly non-physiologic endplate motion can result. Articulation and wear were biased significantly to the superior-bearing surface, even in the presence of significant perturbations of loading and friction. The computational wear model provides novel insight into the mechanics and wear of the Charité TDR, allowing for better interpretation of in vivo results, and giving useful insight for designing future laboratory physical tests.

Case Study on Human Walking during Wearing a Powered Prosthetic Device: Effectiveness of the System “Human-Robot”

Directory of Open Access Journals (Sweden)

Svetlana Grosu

2014-01-01

Full Text Available It is known that force exchanges between a robotic assistive device and the end-user have a direct impact on the quality and performance of a particular movement task. This knowledge finds a special reflective importance in prosthetic industry due to the close human-robot collaboration. Although lower-extremity prostheses are currently better able to provide assistance as their upper-extremity counterparts, specific locomotion problems still remain. In a framework of this contribution the authors introduce the multibody dynamic modelling approach of the transtibial prosthesis wearing on a human body model. The obtained results are based on multibody dynamic simulations against the real experimental data using AMP-Foot 2.0, an energy efficient powered transtibial prosthesis for actively assisted walking of amputees.

Dental wear, wear rate, and dental disease in the African apes.

Science.gov (United States)

Elgart, Alison A

2010-06-01

The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with junction formation until an optimal amount is reached, but excessive wear hinders efficient food processing and may lead to sickness, reduced fecundity, and death. Occlusal surfaces of molars and incisors in three populations each of Gorilla and Pan were videotaped and digitized. The quantity of incisal and molar occlusal dental wear and the lengths of dentin-enamel junctions were measured in 220 adult and 31 juvenile gorilla and chimpanzee skulls. Rates of dental wear were calculated in juveniles by scoring the degree of wear between adjacent molars M1 and M2. Differences were compared by principal (major) axis analysis. ANOVAs compared means of wear amounts. Pearson correlation coefficients were calculated to compare the relationship between molar wear and incidence of dental disease. Results indicate that quantities of wear are significantly greater in permanent incisors and molars and juvenile molars of gorillas compared to chimpanzees. The lengths of dentin-enamel junctions were predominantly suboptimal. Western lowland gorillas have the highest quantities of wear and the most molars with suboptimal wear. The highest rates of wear are seen in Pan paniscus and Pan t. troglodytes, and the lowest rates are found in P.t. schweinfurthii and G. g. graueri. Among gorillas, G. b. beringei have the highest rates but low amounts of wear. Coefficients between wear and dental disease were low, but significant when all teeth were combined. Gorilla teeth are durable, and wear does not lead to mechanical senescence in this sample.

78 FR 4094 - Effective Date of Requirement for Premarket Approval for Two Class III Preamendments Devices

Science.gov (United States)

2013-01-18

... devices. On August 8, 2001, the Orthopaedic and Rehabilitation Devices Panel (the Panel) recommended five... function due to excessive wear, fracture, deformation of the device components, or loosening of the device... excessive wear, fracture, deformation of the device components, or loosening of the device in the surgical...

Characterization of wear mechanism by tribo-corrosion of nickel base alloys

International Nuclear Information System (INIS)

Ionescu, C.C.

2012-01-01

Some components of nuclear power plants, as steam generator tubes are made from Ni base alloys. These components are exposed to severe environment of high temperature and high pressure and submitted to contact mechanical stresses. These Ni - based alloys properties are determined by their ability to form on their surface an inner protective barrier film mainly composed of Cr 2 O 3 . The steam generator tubes are among the most difficult components to maintain, on the hand, because of their safety importance and secondly, the exchange tubes are subject to various degradation mechanisms, because of the harsh conditions of work. Wear by tribo-corrosion is a physicochemical aging mechanism which occurs in the management of the nuclear power plants life time. Tribo-corrosion is an irreversible process which involves mechanical and chemical / electrochemical interactions between surfaces in relative motion, in the presence of a corrosive environment. The goal of this study was to quantify in terms of quantity and quality the wear generated by tribo-corrosion process on Ni - Cr model alloys. Two model alloys: Ni -15Cr and Ni -30Cr were used to highlight, evaluate and compare the influence of the chromium content on the formation of the protective oxide layer and the role played by the latter one on the kinetics and mechanisms of wear by tribo-corrosion. The tribo-corrosion experiments were performed by using a pin-on-disc tribometer under controlled electrochemical conditions in LiOH - H 3 BO 3 solution. The corrosion - wear degradation of the protective layer during continuous and intermittent unidirectional sliding tests was investigated by a three-stage tribo-corrosion protocol. In the first stage, electrochemical techniques (open circuit potential measurements and electrochemical impedance measurements) were used without applying unidirectional sliding to monitor and evaluate the characteristics of protective oxide layer formed on the surface of the two model alloys

Structure vs chemistry: friction and wear of Pt-based metallic surfaces.

Science.gov (United States)

Caron, A; Louzguine-Luzguin, D V; Bennewitz, R

2013-11-13

In comparison of a Pt57.5Cu14.7Ni5.3P22.5 metallic glass with a Pt(111) single crystal we find that wearless friction is determined by chemistry through bond formation alloying, while wear is determined by structure through plasticity mechanisms. In the wearless regime, friction is affected by the chemical composition of the counter body and involves the formation of a liquid-like neck and interfacial alloying. The wear behavior of Pt-based metallic surfaces is determined by their structural properties and corresponding mechanisms for plastic deformation. In the case of Pt(111) wear occurs by dislocation-mediated homogeneous plastic deformation. In contrast the wear of Pt57.5Cu14.7Ni5.3P22.5 metallic glass occurs through localized plastic deformation in shear bands that merge together in a single shear zone above a critical load and corresponds to the shear softening of metallic glasses. These results open a new route in the control of friction and wear of metals and are relevant for the development of self-lubricated and wear-resistant mechanical devices.

A study on mechanism of wear on body seat in nozzle of diesel fuel injector

Energy Technology Data Exchange (ETDEWEB)

Jeonggee, Son; Yamashita, Toru; Sato, Susumu; Kosaka, Hidenori; Masuko, Masabumi [Tokyo Institute of Technology (Japan)

2013-06-01

Wear of nozzle's body seat of diesel fuel injector, which is caused by the collision of needle on the body seat in a nozzle, affects fuel spray behaviors and injection characteristics. Recently, to reduce the wear of body seat, DLC nozzles are widely used. The DLC on the needle which is called diamond-like carbon has a certain effect in reducing wear of body seat. However, disallowable wear is reported at limited engine operating conditions. Moreover, the wear mechanism of body seat with DLC coated needle has not been made clear yet. In this study, the influence of temperature of the body seat and fuel property on the wear of DLC nozzle was investigated with a newly developed wear testing device which was constructed based on common-rail injection system. Worn surfaces of body seat were observed by FE-SEM, laser scanning microscope and EPMA. The obtained results from the measurements show that DLC nozzle has much less wear amount than non-DLC nozzle on the body seat and the corrosive wear effect is suppressed with DLC nozzle. (orig.)

Predicting railway wheel wear under uncertainty of wear coefficient, using universal kriging

International Nuclear Information System (INIS)

Cremona, Marzia A.; Liu, Binbin; Hu, Yang; Bruni, Stefano; Lewis, Roger

2016-01-01

Railway wheel wear prediction is essential for reliability and optimal maintenance strategies of railway systems. Indeed, an accurate wear prediction can have both economic and safety implications. In this paper we propose a novel methodology, based on Archard's equation and a local contact model, to forecast the volume of material worn and the corresponding wheel remaining useful life (RUL). A universal kriging estimate of the wear coefficient is embedded in our method. Exploiting the dependence of wear coefficient measurements with similar contact pressure and sliding speed, we construct a continuous wear coefficient map that proves to be more informative than the ones currently available in the literature. Moreover, this approach leads to an uncertainty analysis on the wear coefficient. As a consequence, we are able to construct wear prediction intervals that provide reasonable guidelines in practice. - Highlights: • Wear prediction is of outmost importance for reliability of railway systems. • Wear coefficient is essential in prediction through Archard's equation. • A novel methodology is developed to predict wear and RUL. • Universal kriging is used for wear coefficient and uncertainty estimation. • A simulation study and a real case application are provided.

Synergistic Interactions of a Synthetic Lubricin-Mimetic with Fibronectin for Enhanced Wear Protection

Directory of Open Access Journals (Sweden)

Roberto C. Andresen Eguiluz

2017-06-01

Full Text Available Lubricin (LUB, a major mucinous glycoprotein of mammalian synovial fluids, is believed to provide excellent lubrication to cartilage surfaces. Consequently, when joint disease or replacement leads to increased friction and surface damage in the joint, robust synthetic LUB alternatives that could be used therapeutically to improve lubrication and surface protection are needed. Here, we report the characterization of a lubricating multiblock bottlebrush polymer whose architecture was inspired by LUB, and we investigate the role of fibronectin (FN, a glycoprotein found in the superficial zone of cartilage, in mediating the tribological properties of the polymer upon shear between mica surfaces. Our surface forces apparatus (SFA normal force measurements indicate that the lubricin-mimetic (mimLUB could be kept anchored between mica surfaces, even under high contact pressures, when an intermediate layer of FN was present. Additional SFA friction measurements show that FN would also extend the wearless friction regime of the polymer up to pressures of 3.4 MPa while ensuring stable friction coefficients (μ ≈ 0.28. These results demonstrate synergistic interactions between mimLUB and FN in assisting the lubrication and wear protection of ideal (mica substrates upon shear. Collectively, these findings suggest that our proposed mimLUB might be a promising alternative to LUB, as similar mechanisms could potentially facilitate the interaction between the polymer and cartilage surfaces in articular joints and prosthetic implants in vivo.

Is clinical performance adversely affected by wearing gloves during paediatric peripheral intravenous cannulation?

Science.gov (United States)

Zhang, Michael; Lee, Mark; Knott, Susan

2014-10-01

To investigate if wearing protective gloves during paediatric intravenous cannulation affects performance of the procedure. This was a prospective observational study. Peripheral intravenous cannulation (PIVC) performed within the Paediatric ED was observed and recorded over a 12 month period. Data were compared between those clinicians wearing gloves and those not wearing gloves during PIVC. One thousand and twenty paediatric cannulations were recorded during the observed period. The mean age of the children was 5.79 years. The overall success rate of cannulation was 86.18% and first attempt success rate 76.08%. Overall, gloves were used by 54.31% of clinicians to establish vascular access; glove use was lowest in the registrar group (41.11% compliance rate). The glove-wearing group had comparable overall success rate of 85.74% (475/554) to the no-gloves group of 86.70% (404/466). The difference was not statistically significant (P > 0.05). Higher incidence of significant blood spillage during the procedure was observed among clinicians wearing no gloves (16.74%) in comparison with their glove-wearing counterparts (9.03%, P glove-wearing group and no-gloves group (3.94% vs 3.76%, P > 0.05). The present study shows that the use of protective gloves was not associated with adverse outcomes of clinical performance during paediatric cannulation. The low compliance rate of gloves use is alarming, and many clinicians might be exposed to potential blood-borne infections. Clinicians should be encouraged and supported to use gloves for paediatric cannulation. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Friction and wear properties of Ti6Al4V/WC-Co in cold atmospheric plasma jet

International Nuclear Information System (INIS)

Xu Wenji; Liu Xin; Song Jinlong; Wu Libo; Sun Jing

2012-01-01

Highlights: ► Cold plasma jet can effectively reduce the friction coefficients of Ti6Al4V/WC-Co friction pairs. ► Cold plasma jet can easily form nitrides on the surface of Ti6Al4V and on new surfaces generated by tool wear. ► The nitrides can reduce the friction coefficients and protect the friction surface. - Abstract: The friction and wear properties of Ti6Al4V/WC-Co friction pair were studied using an autonomous atmospheric pressure bare electrode cold plasma jet generating device and block-on-ring friction/wear tester, respectively. The study was conducted under air, air jet, nitrogen jet, air cold plasma jet, and nitrogen cold plasma jet atmospheres. Both nitrogen cold and air cold plasma jets effectively reduced the friction coefficients of the friction pairs and decreased friction temperature. The friction coefficient in the nitrogen cold plasma jet decreased to almost 60% compared with that in the air. The scanning electron microscope, energy-dispersive X-ray spectroscope, and X-ray diffraction analyses illustrated that adhesive wear was relieved and the friction surfaces of Ti6Al4V were smoother, both in the nitrogen cold and air cold plasma jets. The roughness value R a of the Ti6Al4V friction surfaces can reach 1.107 μm. A large number of nitrogen particles in the ionic and excited states contained by cold plasma jets reacts easily on the friction surface to produce a large amount of nitrides, which can excellently reduce the wear of Ti6Al4V/WC-Co friction pairs in real-time.

Mask-wearing and respiratory infection in healthcare workers in Beijing, China

Directory of Open Access Journals (Sweden)

Peng Yang

Full Text Available OBJECTIVES: The aim of the study was to determine rates of mask-wearing, of respiratory infection and the factors associated with mask-wearing and of respiratory infection in healthcare workers (HCWs in Beijing during the winter of 2007/2008. METHODS: We conducted a survey of 400 HCWs working in eight hospitals in Beijing by face to face interview using a standardized questionnaire. RESULTS: We found that 280/400 (70.0% of HCWs were compliant with mask-wearing while in contact with patients. Respiratory infection occurred in 238/400 (59.5% subjects from November, 2007 through February, 2008. Respiratory infection was higher among females (odds ratio [OR], 2.00 [95% confidence interval {CI}, 1.16-3.49] and staff working in larger hospitals (OR, 1.72 [95% CI, 1.092.72], but was lower among subjects with seasonal influenza vaccination (OR, 0.46 [95% CI, 0.280.76], wearing medical masks (reference: cotton-yarn; OR, 0.60 [95% CI, 0.39-0.91] or with good mask-wearing adherence (OR, 0.60 [95% CI, 0.37-0.98]. The risk of respiratory infection of HCWs working in low risk areas was similar to that of HCWs in high risk area. CONCLUSION: Our data suggest that female HCWs and staffs working in larger hospitals are the focus of prevention and control of respiratory infection in Beijing hospitals. Mask-wearing and seasonal influenza vaccination are protective for respiratory infection in HCWs; the protective efficacy of medical masks is better than that of cotton yarn ones; respiratory infection of HCWs working in low risk areas should also be given attention.

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

Tribological properties of multifunctional coatings with Shape Memory Effect in abrasive wear

Science.gov (United States)

Blednova, Zh. M.; Dmitrenko, D. V.; Balaev, E. U. O.

2018-01-01

The article gives research results of the abrasive wear process on samples made of Steel 1045, U10 and with applied composite surface layer "Nickel-Multicomponent material with Shape Memory Effect (SME) based on TiNi". For the tests we have chosen TiNiZr, which is in the martensite state and TiNiHfCu, which is in the austenitic state at the test temperature. The formation of the surface layer was carried out by high-speed oxygen-fuel deposition in a protective atmosphere of argon. In the wear test, Al2O3 corundum powder was used as an abrasive. It is shown that the wear rate of samples with a composite surface layer of multicomponent materials with SME is significantly reduced in comparison with the base, which is explained by reversible phase transformations of the surface layer with SME. After carrying out the additional surface plastic deformation (SPD), the resistance of the laminated composition to abrasion wear has greatly enhanced, due to the reinforcing effect of the SPD. It is recommended for products working in conditions of abrasive wear and high temperatures to use the complex formation technology of the surface composition "steel-nickel-material with high-temperature SME", including preparation of the substrate surface and the deposited material, high-speed spraying in the protective atmosphere of argon, followed by SPD.

Assessment of wear dependence parameters in complex model of cutting tool wear

Science.gov (United States)

Antsev, A. V.; Pasko, N. I.; Antseva, N. V.

2018-03-01

This paper addresses wear dependence of the generic efficient life period of cutting tools taken as an aggregate of the law of tool wear rate distribution and dependence of parameters of this law's on the cutting mode, factoring in the random factor as exemplified by the complex model of wear. The complex model of wear takes into account the variance of cutting properties within one batch of tools, variance in machinability within one batch of workpieces, and the stochastic nature of the wear process itself. A technique of assessment of wear dependence parameters in a complex model of cutting tool wear is provided. The technique is supported by a numerical example.

Retinal artery occlusion during carotid artery stenting with distal embolic protection device.

Science.gov (United States)

Kohara, Kotaro; Ishikawa, Tatsuya; Kobayashi, Tomonori; Kawamata, Takakazu

2018-01-01

Retinal artery occlusion associated with carotid artery stenosis is well known. Although it can also occur at the time of carotid artery stenting, retinal artery occlusion via the collateral circulation of the external carotid artery is rare. We encountered two cases of retinal artery occlusion that were thought to be caused by an embolus from the external carotid artery during carotid artery stenting with a distal embolic protection device for the internal carotid artery. A 71-year-old man presented with central retinal artery occlusion after carotid artery stenting using the Carotid Guardwire PS and a 77-year-old man presented with branch retinal artery occlusion after carotid artery stenting using the FilterWire EZ. Because additional new cerebral ischaemic lesions were not detected in either case by postoperative diffusion-weighted magnetic resonance imaging, it was highly likely that the debris that caused retinal artery occlusion passed through not the internal carotid artery but collaterals to retinal arteries from the external carotid artery, which was not protected by a distal embolic protection device. It is suggested that a distal protection device for the internal carotid artery alone cannot prevent retinal artery embolisation during carotid artery stenting and protection of the external carotid artery is important to avoid retinal artery occlusion.

Enhancing wear resistance of working bodies of grinder through lining crushed material

Science.gov (United States)

Romanovich, A. A.; Annenko, D. M.; Romanovich, M. A.; Apukhtina, I. V.

2018-03-01

The article presents the analysis of directions of increasing wear resistance of working surfaces of rolls. A technical solution developed at the level of the invention is proposed, which is simple to implement in production conditions and which makes it possible to protect the roll surface from heavy wear due to surfacing of wear-resistant mesh material, cells of which are filling with grinding material in the process of work. Retaining them enables one to protect the roll surface from wear. The paper dwells on conditions of pressing materials in cells of eccentric rolls on the working surface with a grid of rectangular shape. The paper presents an equation for calculation of the cell dimension that provides the lining of the working surface by a mill material with respect to its properties. The article presents results of comparative studies on the grinding process of a press roller grinder (PRG) between rolls with and without a fusion-bonded mesh. It is clarified that the lining of rolls working surface slightly reduces the quality of the grinding, since the material thickness in the cell is small and has a finely divided and compacted structure with high strength.

Tests of microprocessor-based relay protection devices: Problems and solutions

Directory of Open Access Journals (Sweden)

Gurevich Vladimir

2009-01-01

Full Text Available Usually, the operational condition of relay protection devices is checked with specific settings used for the relay operation in a certain network point. In the author's opinion in order to verify the proper operation of complex multifunctional microprocessor-based protection devices (MPD at their inspection, start-up after repairs or during periodic tests there is no need to use the actual settings at which the relay is to be operated in a certain network's point. It should be tested for proper operation at several of its most critical preset characteristic points as well as in several preset characteristics constituting its most complicated (combined operation modes, including the dynamic operation modes with preset transition processes specific for standard power networks (not necessarily for a specific point. The proposed set of actions for the unification of software platforms of the modern, microprocessor-based relay protection test systems will enable examination of modern MPD in an absolutely new way. .

Friction measurement in a hip wear simulator.

Science.gov (United States)

Saikko, Vesa

2016-05-01

A torque measurement system was added to a widely used hip wear simulator, the biaxial rocking motion device. With the rotary transducer, the frictional torque about the drive axis of the biaxial rocking motion mechanism was measured. The principle of measuring the torque about the vertical axis above the prosthetic joint, used earlier in commercial biaxial rocking motion simulators, was shown to sense only a minor part of the total frictional torque. With the present method, the total frictional torque of the prosthetic hip was measured. This was shown to consist of the torques about the vertical axis above the joint and about the leaning axis. Femoral heads made from different materials were run against conventional and crosslinked polyethylene acetabular cups in serum lubrication. Regarding the femoral head material and the type of polyethylene, there were no categorical differences in frictional torque with the exception of zirconia heads, with which the lowest values were obtained. Diamond-like carbon coating of the CoCr femoral head did not reduce friction. The friction factor was found to always decrease with increasing load. High wear could increase the frictional torque by 75%. With the present system, friction can be continuously recorded during long wear tests, so the effect of wear on friction with different prosthetic hips can be evaluated. © IMechE 2016.

Smart Electrochemical Energy Storage Devices with Self-Protection and Self-Adaptation Abilities.

Science.gov (United States)

Yang, Yun; Yu, Dandan; Wang, Hua; Guo, Lin

2017-12-01

Currently, with booming development and worldwide usage of rechargeable electrochemical energy storage devices, their safety issues, operation stability, service life, and user experience are garnering special attention. Smart and intelligent energy storage devices with self-protection and self-adaptation abilities aiming to address these challenges are being developed with great urgency. In this Progress Report, we highlight recent achievements in the field of smart energy storage systems that could early-detect incoming internal short circuits and self-protect against thermal runaway. Moreover, intelligent devices that are able to take actions and self-adapt in response to external mechanical disruption or deformation, i.e., exhibiting self-healing or shape-memory behaviors, are discussed. Finally, insights into the future development of smart rechargeable energy storage devices are provided. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-assembled thin film of imidazolium ionic liquid on a silicon surface: Low friction and remarkable wear-resistivity

International Nuclear Information System (INIS)

Gusain, Rashi; Kokufu, Sho; Bakshi, Paramjeet S.; Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki; Khatri, Om P.

2016-01-01

Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF_6) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF_6 thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF_6 thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF_6 thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF_6 thin film, the covalent interaction between ImPF_6 ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

Self-assembled thin film of imidazolium ionic liquid on a silicon surface: Low friction and remarkable wear-resistivity

Energy Technology Data Exchange (ETDEWEB)

Gusain, Rashi [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India); Kokufu, Sho [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Bakshi, Paramjeet S. [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Khatri, Om P., E-mail: opkhatri@iip.res.in [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India)

2016-02-28

Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF{sub 6}) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF{sub 6} thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF{sub 6} thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF{sub 6} thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF{sub 6} thin film, the covalent interaction between ImPF{sub 6} ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants.

Science.gov (United States)

Turger, Anke; Köhler, Jens; Denkena, Berend; Correa, Tomas A; Becher, Christoph; Hurschler, Christof

2013-08-29

Ceramic materials are used in a growing proportion of hip joint prostheses due to their wear resistance and biocompatibility properties. However, ceramics have not been applied successfully in total knee joint endoprostheses to date. One reason for this is that with strict surface quality requirements, there are significant challenges with regard to machining. High-toughness bioceramics can only be machined by grinding and polishing processes. The aim of this study was to develop an automated process chain for the manufacturing of an all-ceramic knee implant. A five-axis machining process was developed for all-ceramic implant components. These components were used in an investigation of the influence of surface conformity on wear behavior under simplified knee joint motion. The implant components showed considerably reduced wear compared to conventional material combinations. Contact area resulting from a variety of component surface shapes, with a variety of levels of surface conformity, greatly influenced wear rate. It is possible to realize an all-ceramic knee endoprosthesis device, with a precise and affordable manufacturing process. The shape accuracy of the component surfaces, as specified by the design and achieved during the manufacturing process, has a substantial influence on the wear behavior of the prosthesis. This result, if corroborated by results with a greater sample size, is likely to influence the design parameters of such devices.

Implementation of Transformer Protection by Intelligent Electronic Device for Different Faults

OpenAIRE

Y V Aruna, Beena S

2015-01-01

Protection of power system equipments was traditionally done by using electromagnetic relay, static relays, and numerical relays. At present the microprocessor based relays are replacing the old Electromagnetic relays because of their high level accuracy and fast operation. RET670(Transformer protection relay ), an IED (INTELLIGENT ELECTRONIC DEVICE) provides fast and selective protection, monitoring, and control of all types of transformer. The configured IED is tested under diff...

State of the art in protection of erosion-corrosion on vertical axis tidal current turbine

Science.gov (United States)

Musabikha, Siti; Utama, I. Ketut Aria Pria; Mukhtasor

2018-05-01

Vertical axis tidal current turbine is main part of ocean energy devices which converts the tidal current energy into electricity. Its development is arising too due to increased interest research topic concerning climate change mitigation. Due to its rotating movement, it will be induced mechanical forces, such as shear stress and/or particle impact. Because of its natural operations, vertical axis turbine is also being exposed to harsh and corroding marine environment itself. In order to secure the vertical tidal turbine devices from mechanical wear and corrosion effects which is lead to a material loss, an appropriate erosion-corrosion protection needs to be defined. Its protection actionscan be derived such as design factors, material selections, inhibitors usage, cathodic protections, and coatings. This paper aims to analyze protection method which is necessary to control erosion-corrosion phenomenon that appears to the vertical axis tidal current turbine.

In Their Own Words: Interviews with Musicians Reveal the Advantages and Disadvantages of Wearing Earplugs.

Science.gov (United States)

Beach, Elizabeth F; O'Brien, Ian

2017-06-01

Musicians are at risk of hearing loss from sound exposure, and earplugs form part of many musicians' hearing conservation practices. Although musicians typically report a range of difficulties when wearing earplugs, there are many who have managed to successfully incorporate earplugs into their practice of music. The study aim was to provide a detailed account of earplug usage from the perspective of the musician, including motivating factors, practical strategies, and attitudes. In-depth interviews with 23 musicians were transcribed and content analysis was performed. Responses were coded and classified into three main themes: advantages, disadvantages, and usage patterns and strategies, together with an overlapping fourth theme, youth perspectives. Several positive aspects of wearing earplugs were identified, including long-term hearing protection and reduced levels of fatigue and pain. Musicians reported that earplugs present few problems for communication, improve sound clarity in ensembles, are discreet, and are easy to handle. However, earplugs also present challenges, including an overall dullness of sound, reduced immediacy, and an impaired ability to judge balance and intonation due to the occlusion effect, all of which influence usage habits and patterns. The experiences of the younger musicians and long-term users of earplugs indicate that practice, persistence, and a flexible approach are required for successful earplug usage. In time, there may be greater acceptance of earplugs, particularly amongst a new generation of musicians, some of whom regard the earplugs as a performance enhancement tool as well as a protective device.

A Low-wear Planar-contact Silicon Raceway for Microball Bearing Applications

Science.gov (United States)

2009-04-01

of friction between stainless steel microballs and silicon grooves (18–20). Both linear and rotary micromotors for sensor platforms were developed...mechanism, like a micromotor , will enable devices to reach higher speeds. Previously, the radial surface wear track depth was >15 m for a device...can lead to significant whirl and axial misalignment, which is critical for micromotor and micropump applications. Small changes in the alignment

Improvement of Wearable Power Assist Wear for Low Back Support using Pneumatic Actuator

Science.gov (United States)

Cho, Feifei; Sugimoto, Riku; Noritsugu, Toshiro; Li, Xiangpan

2017-10-01

This study focuses on developing a safe, lightweight, power assist device that can be worn by people who like caregivers during lifting or static holding tasks to prevent low back pain (LBP). Therefore in consideration of their flexibility, light weight, and large force to weight ratio we have developed a Wearable Power Assist Wear for caregivers, two types of pneumatic actuators are employed in assisting low back movement for their safety and comfort. The device can be worn directly on the body like normal clothing. Because there is no rigid exoskeleton frame structure, it is lightweight and user friendly. In this paper, we proposed the new type of the wearable power assist wear and improved the controller of control system.

The Amount of Wear in Attachment of Implant-Supported Overdentures in Mandible

Directory of Open Access Journals (Sweden)

Fariborz Vafaee

2016-10-01

Full Text Available Background and objectives: One of the simplest and cheapest attachments for overdentures, is the ball-type attachment, however, keeping it during the first year of prosthesis delivery and after that is one of the main concerns of dentists. The present study aimed to assess the wear of matrix in overdentures attachment supported by one, two and three implants in the mandible. Materials and methods: Thirty edentulous patients were randomly divided into three groups: the first group received a single implant in the midline of the lower mandible, the second group two implants in areas B and D, and the third group three implants in areas B, C, and D. The attachment used in patients’ prosthetic with single and two implants was O-ball/ring attachment and for patients with three implants, the treatment plan was ball bar-supported attachments. After placing the new matrix implant for each patient and obtaining their consent, the matrix wear was measured with CMM (Coordinate Measuring Machine device. To compare matrix wear after six months and one year, measurements were repeated. Data analysis, using ANOVA and multiple comparisons was down by Tukey Test. variance with repeated measures and Tukey test were used to compare the groups two-by-two. P.value less than 0.05 was set statistical significant. SPSS 16 software was used for data analysis. Results: The data obtained from the CMM device showed that the lowest mean matrix wear in the maximum single implant and maximum mean were in group two. Conclusion: Both time and the number of implants had a significant effect on the wear of the O-ring.

Clothing, equipment and devices for personnel protection: Its selection according to occupational risks

International Nuclear Information System (INIS)

1989-01-01

This Venezuelan standard establishes the selection of the type of clothing, equipment and devices for personnel protection, to be used by workers according to the occupational risk they deal with, in order to avoid or to reduce the factors that can, directly or indirectly, affect their physical integrity. For the risks not contemplated in this norm, the selection of the type of clothing, equipment and devices for personnel protection, must be done following the corresponding international standard [es

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.

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

. The mean wear depth was measured using the traditionally employed 2D and compared with the 3D profilometric (digital) techniques. Data were submitted to analyses of variance, Tukey's post hoc tests and Independent Samples Student's t-tests (where appropriate) at p...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...... for Tandheelkunde Amsterdam (ACTA) wear machine. METHODS: Specimens compatible with the compartments of the ACTA wear machine specimen wheel (n=10) were prepared from one commercial and four experimental RBCs. The RBC specimens were rotated against an antagonist wheel in a food-like slurry for 220,000 wear cycles...

Nitrogen implantation of type 303 stainless steel gears for improved wear and fatigue resistance

International Nuclear Information System (INIS)

Kustas, F.M.; Misra, M.S.; Tack, W.T.

1987-01-01

Fine-positioning mechanisms are responsible for accurate and reproducible control of aerospace system devices, i.e. filter grading wheels. Low wear and fatigue resistance of mechanism components, such as pinions and gears, can reduce system performance and reliability. Surface modification using ion implantation with nitrogen was used on type 303 stainless steel pinions and gears to increase tribological performance. Wear-life tests of untreated, nitrogen-implanted and nitrogen-implanted-and-annealed gears were performed in a fine-positioning mechanism under controlled environmental conditions. Wear and fatigue resistance were monitored at selected time intervals which were a percentage of the predicted failure life as determined by a numerical stress analysis. Surface analyses including scanning electron microscopy and Auger electron spectroscopy were performed to establish the wear and fatigue mechanisms and the nitrogen concentration-depth distributions respectively. Nitrogen implantation resulted in a significant improvement in both surface wear and fatigue spalling resistance over those of untreated gears. A 40% reduction in surface wear and a 44% reduction in dedendum spalling was observed. In contrast, the nitrogen-implanted-and-annealed gears showed a 46% increase in sliding wear area and an 11% increase in spall density compared with those of untreated gears, indicating that the post-implantation anneal was detrimental to wear and fatigue resistance. (orig.)

Polyethylene wear in Oxford unicompartmental knee replacement: a retrieval study of 47 bearings.

Science.gov (United States)

Kendrick, B J L; Longino, D; Pandit, H; Svard, U; Gill, H S; Dodd, C A F; Murray, D W; Price, A J

2010-03-01

The Oxford Unicompartmental Knee replacement (UKR) was introduced as a design to reduce polyethylene wear. There has been one previous retrieval study involving this implant, which reported very low rates of wear in some specimens but abnormal patterns of wear in others. There has been no further investigation of these abnormal patterns. The bearings were retrieved from 47 patients who had received a medial Oxford UKR for anteromedial osteoarthritis of the knee. None had been studied previously. The mean time to revision was 8.4 years (sd 4.1), with 20 having been implanted for over ten years. The macroscopic pattern of polyethylene wear and the linear penetration were recorded for each bearing. The mean rate of linear penetration was 0.07 mm/year. The patterns of wear fell into three categories, each with a different rate of linear penetration; 1) no abnormal macroscopic wear and a normal articular surface, n = 16 (linear penetration rate = 0.01 mm/year); 2) abnormal macroscopic wear and normal articular surfaces with extra-articular impingement, n = 16 (linear penetration rate = 0.05 mm/year); 3) abnormal macroscopic wear and abnormal articular surfaces with intra-articular impingement +/- signs of non-congruous articulation, n = 15 (linear penetration rate = 0.12 mm/year). The differences in linear penetration rate were statistically significant (p < 0.001). These results show that very low rates of polyethylene wear are possible if the device functions normally. However, if the bearing displays suboptimal function (extra-articular, intra-articular impingement or incongruous articulation) the rates of wear increase significantly.

Protective device for the head of a gushing well

Energy Technology Data Exchange (ETDEWEB)

Kutepov, A.I.; Prokopov, O.I.

1982-01-01

A protective device is proposed for the head of a gushing well. It includes a housing with assembly for attachment to the pipe string. It is distinguished by the fact that in order to simplify insulation of the device at the well head and to improve its reliable operation, the housing is made in the form of sections, each of which is made in the form of a crimped sleeve with upper and lower flanges on the ends. The lower flange is equipped with a guide bushing installed inside the sleeve and clamps for attaching it in relation to the upper flange.

The Tribological Performance of Hardfaced/ Thermal Sprayed Coatings for Increasing the Wear Resistance of Ventilation Mill Working Parts

Directory of Open Access Journals (Sweden)

A. Vencl

2015-09-01

Full Text Available During the coal pulverizing, the working parts of the ventilation mill are being worn by the sand particles. For this reason, the working parts are usually protected with materials resistant to wear (hardfaced/thermal sprayed coatings. The aim of this study was to evaluate the tribological performance of four different types of coatings as candidates for wear protection of the mill’s working parts. The coatings were produced by using the filler materials with the following nominal chemical composition: NiFeBSi-WC, NiCrBSiC, FeCrCTiSi, and FeCrNiCSiBMn, and by using the plasma arc welding and flame and electric arc spraying processes. The results showed that Ni-based coatings exhibited higher wear resistance than Fe-based coatings. The highest wear resistance showed coating produced by using the NiFeBSi-WC filler material and plasma transferred arc welding deposition process. The hardness was not the only characteristic that affected the wear resistance. In this context, the wear rate of NiFeBSi-WC coating was not in correlation with its hardness, in contrast to other coatings. The different wear performance of NiFeBSi-WC coating was attributed to the different type and morphological features of the reinforcing particles (WC.

Awareness and utilization of protective eye device among welders in ...

African Journals Online (AJOL)

Ramakantb

was a high level of awareness of protective eye devices among the welders (367, 90.6%), being higher among arc welders compared ... each respondent in the field. The welders' ... Thermal retinal damage can also occur from near infrared ...

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

Friction and Wear of Unlubricated NiTiHf with Nitriding Surface Treatments

Science.gov (United States)

Stanford, Malcolm K.

2018-01-01

The unlubricated friction and wear properties of the superelastic materials NiTi and NiTiHf, treated by either gas nitriding or plasma nitriding, have been investigated. Pin on disk testing of the studied materials was performed at sliding speeds from 0.01 to 1m/s at normal loads of 1, 5 or 10N. For all of the studied friction pairs (NiTiHf pins vs. NiTi and NiTiHf disks) over the given parameters, the steady-state coefficients of friction varied from 0.22 to 1.6. Pin wear factors ranged from approximately 1E-6 against the NiTiHf and plasma nitrided disks to approximately 1E-4 for the gas nitrided disks. The plasma nitrided disks provided wear protection in several cases and tended to wear by adhesion. The gas nitrided treatment generated the most pin wear but had essentially no disk wear except at the most severe of the studied conditions (1N load and 1m/s sliding speed). The results of this study are expected to provide guidance for design of components such as gears and fasteners.

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

OpenAIRE

Richter, Berna I; Ostermeier, Sven; Turger, Anke; Denkena, Berend; Hurschler, Christof

2010-01-01

Abstract Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which sim...

Optimisation of staff protection

International Nuclear Information System (INIS)

Faulkner, K.; Marshall, N.W.; Rawlings, D.J.

1997-01-01

It is important to minimize the radiation dose received by staff, but it is particularly important in interventional radiology. Staff doses may be reduced by minimizing the fluoroscopic screening time and number of images, compatible with the clinical objective of the procedure. Staff may also move to different positions in the room in an attempt to reduce doses. Finally, staff should wear appropriate protective clothing to reduce their occupational doses. This paper will concentrate on the optimization of personal shielding in interventional radiology. The effect of changing the lead equivalence of various protective devices on effective dose to staff has been studied by modeling the exposure of staff to realistic scattered radiation. Both overcouch x-ray tube/undercouch image intensified and overcouch image intensifier/undercouch x-ray tube geometries were simulated. It was deduced from this simulation that increasing the lead apron thickness from 0.35 mm lead to 0.5 mm lead had only a small reducing effect. By contrast, wearing a lead rubber thyroid shield or face mask is a superior means of reducing the effective dose to staff. Standing back from the couch when the x-ray tube is emitting radiation is another good method of reducing doses, being better than exchanging a 0.35 mm lead apron for a 0.5 mm apron. In summary, it is always preferable to shield more organs than to increase the thickness of the lead apron. (author)

MODELING OF POWER SYSTEMS AND TESTING OF RELAY PROTECTION DEVICES IN REAL AND MODEL TIME

Directory of Open Access Journals (Sweden)

I. V. Novash

2017-01-01

Full Text Available The methods of modelling of power system modes and of testing of relay protection devices with the aid the simulation complexes in real time and with the help of computer software systems that enables the simulation of virtual time scale are considered. Information input protection signals in the simulation of the virtual model time are being obtained in the computational experiment, whereas the tests of protective devices are carried out with the help of hardware and software test systems with the use of estimated input signals. Study of power system stability when modes of generating and consuming electrical equipment and conditions of devices of relay protection are being changed requires testing with the use of digital simulators in a mode of a closed loop. Herewith feedbacks between a model of the power system operating in a real time and external devices or their models must be determined (modelled. Modelling in real time and the analysis of international experience in the use of digital simulation power systems for real-time simulation (RTDS simulator have been fulfilled. Examples are given of the use of RTDS systems by foreign energy companies to test relay protection systems and control, to test the equipment and devices of automatic control, analysis of cyber security and evaluation of the operation of energy systems under different scenarios of occurrence of emergency situations. Some quantitative data on the distribution of RTDS in different countries and Russia are presented. It is noted that the leading energy universities of Russia use the real-time simulation not only to solve scientific and technical problems, but also to conduct training and laboratory classes on modelling of electric networks and anti-emergency automatic equipment with the students. In order to check serviceability of devices of relay protection without taking into account the reaction of the power system tests can be performed in an open loop mode with the

Preparation, characterization and wear behavior of carbon coated magnesium alloy with electroless plating nickel interlayer

International Nuclear Information System (INIS)

Mao, Yan; Li, Zhuguo; Feng, Kai; Guo, Xingwu; Zhou, Zhifeng; Dong, Jie; Wu, Yixiong

2015-01-01

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

Evolution of metal-metal wear mechanisms in martensitic steel deposits for recharging

International Nuclear Information System (INIS)

Gualco, Agustin; Svoboda, Hernan G; Surian, Estela S; De Vedia, Luis A

2008-01-01

This work studied metal recharged by welding with a martensitic steel (Cr, Mn, Mo, V and W alloy), deposited with a metal filled tubular wire on a low carbon steel, using semi-automatic welding with a contributing heat of 2 kJ/mm and under a gaseous protection of Ar-2%CO 2 . Transverse cuts were extracted from the welded sample for microstructural characterization, hardness measurement, determination of chemical composition and wear tests. The microstructural characterization was performed using light microscopy (LM) and scanning electron microscopy (SEM), X-Ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The wear tests (metal-metal) were carried out on an Amsler machine in natural flow condition, with 500, 1250 and 2000 N of applied charge. The reference material was SAE 1020 steel. The weight loss curves were determined as a function of the distance run up to 5000 meters for all conditions. Then the test's wear surfaces and debris were analyzed. The microstructure consisted mostly of martensite and a fraction of retained austenite. A pattern of dendritic segregation was observed. The hardness on the wear surface averaged 670 HV 1 . The wear behavior showed a lineal variation between the loss of weight and the distance run, for the different loads applied. The rates of wear for each condition were obtained. The observed wear mechanisms were abrasion and adhesion, with plastic deformation. At low charges, the predominant mechanism was mild oxidative wear and at bigger loads heavy oxidative wear with the presence of zones with adhesion. The oxides formed on the surface of the eroded plate were identified

Abrasive wear of intermetallics

International Nuclear Information System (INIS)

Hawk, J.A.; Alman, D.E.; Wilson, R.D.

1995-01-01

The US Bureau of Mines is investigating the wear behavior of a variety of advanced materials. Among the many materials under evaluation are intermetallic alloys based on the compounds: Fe 3 Al, Ti 3 Al, TiAl, Al 3 Ti, NiAl and MoSi 2 . The high hardness, high modulus, low density, and superior environmental stability of these compounds make them attractive for wear materials. This paper reports on the abrasive wear of alloys and composites based on the above compounds. The abrasive wear behavior of these alloys and composites are compared to other engineering materials used in wear applications

FiberNet--a new embolic protection device for carotid artery stenting.

Science.gov (United States)

Bauer, C; Franke, J; Bertog, S C; Woerner, V; Ghasemzadeh-Asl, S; Sievert, H

2014-05-01

Though distal filter protection during carotid stenting reduces the risk of cerebrovascular events, periprocedural stroke remains a risk despite their broad usage. This observation may be related to the pore size of common filters. The FiberNet distal filter system is unique by its very small pore size (40 µm) as well as its low profile and flexibility. Little data is available regarding the clinical performance and safety of this device. The aim was the evaluation of the safety of the FiberNet embolic protection system during carotid artery stenting. All consecutive patients treated with carotid stenting at our institution using the FiberNet device were systematically followed. Primary endpoint was the rate of all death and stroke within 30 days of the procedure. Carotid artery stenting using the FiberNet embolic protection system was performed in 54 patients. The procedure was technical successful in all patients. Three patients (5.5%) had a TIA. Amauosis fugax occurred in two patients (3.7%). One patient (1.9%) had a minor stroke with hemiparesis of the left arm and face which resolved completely within 48 hr after the procedure. No patient died or suffered a major stroke. The safety and feasibility of the FiberNet distal protection system appears to be at least equivalent to that reported in studies using conventional distal filter protection. Copyright © 2013 Wiley Periodicals, Inc.

Electronic Systems for the Protection of Superconducting Devices in the LHC

CERN Document Server

Denz, R; Mess, K H

2008-01-01

The Large Hadron Collider LHC [1] incorporates an unprecedented amount of superconducting components: magnets, bus-bars, and current leads. Most of them require active protection in case of a transition from the superconducting to the resistive state, the so-called quench. The electronic systems ensuring the reliable quench detection and further protection of these devices have been developed and produced over the last years and are currently being put into operation

Sliding wear studies of sprayed chromium carbide-nichrome coatings for gas-cooled reactor applications

International Nuclear Information System (INIS)

Li, C.C.; Lai, G.Y.

1978-09-01

Chromium carbide-nichrome coatings being considered for wear protection of some critical components in high-temperature gas-cooled reactors (HTGR's) were investigated. The coatings were deposited either by the detonation gun or the plasma-arc process. Sliding wear tests were conducted on specimens in a button-on-plate arrangement with sliding velocities of 7.1 x 10 -3 and 7.9 mm/s at 816 0 C in a helium environment simulates HTGR primary coolant chemistry. The coatings containing 75 or 80 wt % chromium carbide exhibited excellent wear resistance. As the chromium carbide content decreased from either 80 or 75 to 55 wt %, with a concurrent decrease in coating hardness, wear-resistance deteriorated. The friction and wear behavior of the soft coating was similar to that of the bare metal--showing severe galling and significant amounts of wear debris. The friction characteristics of the hard coating exhibited a strong velocity dependence with high friction coefficients in low sliding velocity tests ad vice versa. Both the soft coating and bare metal showed no dependence on sliding velocity. The wear behavior observed in this study is of adhesive type, and the wear damage is believed to be controlled primarily by the delamination process

Surge protective device response to steep front transient in low voltage circuit

Energy Technology Data Exchange (ETDEWEB)

Marcuz, J.; Binczak, S.; Bilbault, J.M. [Universite de Bourgogne, Dijon (France)], Emails: jerome.marcuz@ laposte.net, stbinc@u-bourgogne.fr, bilbault@u-bourgogne.fr; Girard, F. [ADEE Electronic, Pont de Pany (France)

2007-07-01

Surge propagation on cables of electrical or data lines leads to a major protection problem as the number of equipment based on solid-state circuits or microprocessors increases. Sub-microsecond components of real surge waveform has to be taken into account for a proper protection even in the case of surges caused by indirect lightning effects. The response of a model of transient voltage suppressor diode based surge protection device (SPD) to fast front transient is analytically studied, then compared to simulations, including the lines connected to the SPD and to the protected equipment. (author)

Variations in voice level and fundamental frequency with changing background noise level and talker-to-listener distance while wearing hearing protectors: A pilot study.

Science.gov (United States)

Bouserhal, Rachel E; Macdonald, Ewen N; Falk, Tiago H; Voix, Jérémie

2016-01-01

Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes in voice level and fundamental frequency in noise and with varying talker-to-listener distance. Twelve participants with a mean age of 28 participated in this study. Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded quiet condition. This implies that a model can be developed to better understand speech production for the occluded ear.

A study on ship impacting a flexible crashworthy device for protecting bridge pier

Directory of Open Access Journals (Sweden)

Yang Liming

2015-01-01

Full Text Available As the accident of a vessel impacting a bridge pier will cause serious disaster, such as destroyed bridge, sinking ship and polluting environment, the technology and method to protect bridge pier from ship collision have been widely investigated recently. Due to the huge kinetic energy of large-tonnage ship and the short time duration in the collision, the studies involve impact mechanics. A developed flexible crashworthy device has been developed to protect bridges, which consists of an outer steel-periphery, an inner steel-periphery and the rubber coating SWRCs(soft elements installed between them. When the SWRC crashworthy device is installed, the collision duration under low impact force is prolonged due to its high compliance, which results in the ship having enough time to turn its navigation direction and most of the remainder kinetic energy being carried off by the turned away ship. Consequently, both impact forces on the ship and on the bridge pier decrease markedly. This is the key reason as to why the SWRC crashworthy device can avoid the destruction of both the bridge and the ship. Based on our results of theoretical studies and numerical simulations, the present paper will propose an experiment-adopted a real ship to impact a flexible crashworthy device. The collision test has been performed 12 times with different speed, carrying capacity, and impact angle of the ship. After the experiments, the ship, flexible crashworthy device and the pier are not damaged. The experiments show that the flexible crashworthy device can turn away the impact ship, so that the ship moves along the outer part of the device, which reduces the ship impact force on the bridge pier obviously. It not only protects bridges but also avoids the damage to ships.

Analysis of mechanism of carbide tool wear and control by wear process

Directory of Open Access Journals (Sweden)

Pham Hoang Trung

2017-01-01

Full Text Available The analysis of physic-mechanical and thermal physic properties of hard alloys depending on their chemical composition is conducted. The correlation of cutting properties and regularities of carbide tool wear with cutting conditions and thermal physic properties of tool material are disclosed. Significant influence on the tool wear of not only mechanical, but, in the first place, thermal physic properties of tool and structural materials is established by the researches of Russian scientists, because in the range of industrial used cutting speeds the cause of tool wear are diffusion processes. The directions of intensity decreasing of tool wear by determining rational processing conditions, the choice of tool materials and wear-resistant coating on tool surface are defined.

Influence of nitrogen ion implantation on wear studied by a new laboratory wear test

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E.; Paszti, F.; Vertessy, Z. (Central Research Inst. for Physics, Hungarian Academy of Sciences, Budapest (Hungary))

1991-05-01

A new laboratory wear test is developed in which the wear trace is measured by Rutherford backscattering spectrometry. The advantage of the new test is that the wear rate is directly determinable. The new test setup has been used to study the effects of nitrogen implantation on the wear processes on 115CrV3 steel. The wear rate decreases by a factor of 2 at 4x10{sup 17} N{sup +}/cm{sup 2} implanted dose. (orig.).

A Study on the technology of the Protective Device Application for the power Telecommunication Facilities

Energy Technology Data Exchange (ETDEWEB)

Lee, B.K.; Lee, S.J.; Choi, H.Y. [Korea Electric Power Research Insitute, Taejeon (Korea, Republic of); Lee, B.H.; Jeon, D.K.; Lee, K.O.; Ahn, C.H.; Kim, S.O.; Kim, J.S. [Electrical Engineering and Science Research Center, Seoul (Korea, Republic of)

1997-12-31

In order to protect the power telecommunication system from surge by lightning or switching and ground potential rise, characteristics of surge are analyzed when surge strikes communication system. Surge generator which meets international standard was made and test of protective devices was carried out by using it. Counter measures against surge is established through the analysis of ground potential which varies with transient ground impedance. Also specification for installing protective devices was recommended, which is proper to apply to the field system. (author). 186 refs., 203 figs., 21 tabs.

Fish protection at steam-electric power plants: alternative screening devices

International Nuclear Information System (INIS)

Cannon, J.B.

1978-01-01

Since the enactment of the Federal Water Pollution Control Act Amendments of 1972, very few innovations have surfaced that advance the state of intake technology for fish protection at steam-electric power plants. After careful examination of basic hydrology, hydraulics, and ecology of the source water body is completed and after a suitable location for the intake is established, the design process reduces to the development of proper screening techniques and to the provision of a means of preventing resident and migratory species from entering the intake structure. As a result of this design process, three basic fish protection concepts have evolved: fish deterrence, fish collection and removal, and fish diversion. Intake screening devices that protect fish are discussed

Tribology of Si/SiO2 in humid air: transition from severe chemical wear to wearless behavior at nanoscale.

Science.gov (United States)

Chen, Lei; He, Hongtu; Wang, Xiaodong; Kim, Seong H; Qian, Linmao

2015-01-13

Wear at sliding interfaces of silicon is a main cause for material loss in nanomanufacturing and device failure in microelectromechanical system (MEMS) applications. However, a comprehensive understanding of the nanoscale wear mechanisms of silicon in ambient conditions is still lacking. Here, we report the chemical wear of single crystalline silicon, a material used for micro/nanoscale devices, in humid air under the contact pressure lower than the material hardness. A transmission electron microscopy (TEM) analysis of the wear track confirmed that the wear of silicon in humid conditions originates from surface reactions without significant subsurface damages such as plastic deformation or fracture. When rubbed with a SiO2 ball, the single crystalline silicon surface exhibited transitions from severe wear in intermediate humidity to nearly wearless states at two opposite extremes: (a) low humidity and high sliding speed conditions and (b) high humidity and low speed conditions. These transitions suggested that at the sliding interfaces of Si/SiO2 at least two different tribochemical reactions play important roles. One would be the formation of a strong "hydrogen bonding bridge" between hydroxyl groups of two sliding interfaces and the other the removal of hydroxyl groups from the SiO2 surface. The experimental data indicated that the dominance of each reaction varies with the ambient humidity and sliding speed.

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

First-in-man use of a novel embolic protection device for patients undergoing transcatheter aortic valve implantation.

Science.gov (United States)

Naber, Christoph K; Ghanem, Alexander; Abizaid, Alexander A; Wolf, Alexander; Sinning, Jan-Malte; Werner, Nikos; Nickenig, Georg; Schmitz, Thomas; Grube, Eberhard

2012-05-15

We describe the first-in-human experience with a novel cerebral embolic protection device used during transcatheter aortic valve implantation (TAVI). One current challenge of TAVI is the reduction of procedural stroke. Procedural mobilisation of debris is a known source of cerebral embolisation. Mechanical protection by transient filtration of cerebral blood flow might reduce the embolic burden during TAVI. We aimed to evaluate the feasibility and safety of the Claret CE Pro™ cerebral protection device in patients undergoing TAVI. Patients scheduled for TAVI were prospectively enrolled at three centres. The Claret CE Pro™ (Claret Medical, Inc. Santa Rosa, CA, USA) cerebral protection device was placed via the right radial/brachial artery prior to TAVI and was removed after the procedure. The primary endpoint was technical success rate. Secondary endpoints encompassed procedural and 30-day stroke rates, as well as device-related complications. Deployment of the Claret CE Pro™ cerebral protection device was intended for use in 40 patients, 35 devices were implanted into the aortic arch. Technical success rate with delivery of the proximal and distal filter was 60% for the first generation device and 87% for the second-generation device. Delivery times for the first-generation device were 12.4±12.1 minutes and 4.4 ± 2.5 minutes for the second-generation device (pto the Claret CE Pro System was 19.6 ± 3.8 ml. Captured debris was documented in at least 19 of 35 implanted devices (54.3%). No procedural transient ischaemic attacks, minor strokes or major strokes occurred. Thirty-day follow-up showed one minor stroke occurring 30 days after the procedure, and two major strokes both occurring well after the patient had completed TAVI. The use of the Claret CE Pro™ system is feasible and safe. Capture of debris in more than half of the patients provides evidence for the potential to reduce the procedural cerebral embolic burden utilising this dedicated filter

THE CORROSION BEHAVIOR AND WEAR RESISTANCE OF GRAY CAST IRON

Directory of Open Access Journals (Sweden)

Lina F. Kadhim

2018-01-01

Full Text Available Gray cast iron has many applications as pipes , pumps and valve bodies where it has influenced by heat and contact with other solutions . This research has studied the corrosion behavior and Vickers hardness of gray cast iron by immersion in four strong alkaline solutions (NaOH, KOH, Ca(OH2, LiOHwith three concentrations (1%,2%,3% of each solution. Dry sliding wear has carried out before and after the heat treatments (stress relief ,normalizing, hardening and tempering. In this work ,maximum wear strength has obtained at tempered gray cast iron and minimum corrosion rate has obtained in LiOH solution by forming protective white visible oxide layer.

The Biologic Response to Polyetheretherketone (PEEK) Wear Particles in Total Joint Replacement: A Systematic Review.

Science.gov (United States)

Stratton-Powell, Ashley A; Pasko, Kinga M; Brockett, Claire L; Tipper, Joanne L

2016-11-01

Polyetheretherketone (PEEK) and its composites are polymers resistant to fatigue strain, radiologically transparent, and have mechanical properties suitable for a range of orthopaedic applications. In bulk form, PEEK composites are generally accepted as biocompatible. In particulate form, however, the biologic response relevant to joint replacement devices remains unclear. The biologic response to wear particles affects the longevity of total joint arthroplasties. Particles in the phagocytozable size range of 0.1 µm to 10 µm are considered the most biologically reactive, particularly particles with a mean size of PEEK-based wear debris from total joint arthroplasties. (1) What are the quantitative characteristics of PEEK-based wear particles produced by total joint arthroplasties? (2) Do PEEK wear particles cause an adverse biologic response when compared with UHMWPE or a similar negative control biomaterial? (3) Is the biologic response affected by particle characteristics? Embase and Ovid Medline databases were searched for studies that quantified PEEK-based particle characteristics and/or investigated the biologic response to PEEK-based particles relevant to total joint arthroplasties. The keyword search included brands of PEEK (eg, MITCH, MOTIS) or variations of PEEK types and nomenclature (eg, PAEK, CFR-PEEK) in combination with types of joint (eg, hip, knee) and synonyms for wear debris or immunologic response (eg, particles, cytotoxicity). Peer-reviewed studies, published in English, investigating total joint arthroplasty devices and cytotoxic effects of PEEK particulates were included. Studies investigating devices without articulating bearings (eg, spinal instrumentation devices) and bulk material or contact cytotoxicity were excluded. Of 129 studies, 15 were selected for analysis and interpretation. No studies were found that isolated and characterized PEEK wear particles from retrieved periprosthetic human tissue samples. In the four studies that

Evaluating Tree Protection Devices: Effects on Growth and Survival–First-Year Results

Science.gov (United States)

L. R. Costello; R. H. Schmidt; Gregory A. Giusti

1991-01-01

The protection of seedlings from animal browsing is critical for the survival and growth of many tree species. This is particularly true in wildland areas and arid areas (McAuliffe, 1986), and oftentimes in urban areas. A variety of techniques and devices have been used to protect seedlings, from using straw stubble to milk cartons to plastic or metal screens. Recently...

Wear Behavior and Microstructure of Mg-Sn Alloy Processed by Equal Channel Angular Extrusion.

Science.gov (United States)

Chen, Jung-Hsuan; Shen, Yen-Chen; Chao, Chuen-Guang; Liu, Tzeng-Feng

2017-11-16

Mg-5wt.% Sn alloy is often used in portable electronic devices and automobiles. In this study, mechanical properties of Mg-5wt.% Sn alloy processed by Equal Channel Angular Extrusion (ECAE) were characterized. More precisely, its hardness and wear behavior were measured using Vickers hardness test and a pin-on-disc wear test. The microstructures of ECAE-processed Mg-Sn alloys were investigated by scanning electron microscope and X-ray diffraction. ECAE process refined the grain sizes of the Mg-Sn alloy from 117.6 μm (as-cast) to 88.0 μm (one pass), 49.5 μm (two passes) and 24.4 μm (four passes), respectively. Meanwhile, the hardness of the alloy improved significantly. The maximum wear resistance achieved in the present work was around 73.77 m/mm³, which was obtained from the Mg-Sn alloy treated with a one-pass ECAE process with a grain size of 88.0 μm. The wear resistance improvement was caused by the grain size refinement and the precipitate of the second phase, Mg₂Sn against the oxidation of the processed alloy. The as-cast Mg-Sn alloy with the larger grain size, i.e., 117.6 μm, underwent wear mechanisms, mainly adhesive wear and abrasive wear. In ECAE-processed Mg-Sn alloy, high internal energy occurred due to the high dislocation density and the stress field produced by the plastic deformation, which led to an increased oxidation rate of the processed alloy during sliding. Therefore, the oxidative wear and a three-body abrasive wear in which the oxide debris acted as the three-body abrasive components became the dominant factors in the wear behavior, and as a result, reduced the wear resistance in the multi-pass ECAE-processed alloy.

Protection relay of phase-shifting device with thyristor switch for high voltage power transmission lines

Science.gov (United States)

Lachugin, V. F.; Panfilov, D. I.; Akhmetov, I. M.; Astashev, M. G.; Shevelev, A. V.

2014-12-01

Problems of functioning of differential current protection systems of phase shifting devices (PSD) with mechanically changed coefficient of transformation of shunt transformer are analyzed. Requirements for devices of protection of PSD with thyristor switch are formulated. Based on use of nonlinear models of series-wound and shunt transformers of PSD modes of operation of major protection during PSD, switching to zero load operation and to operation under load and during short circuit operation were studied for testing PSD with failures. Use of the principle of duplicating by devices of differential current protection (with realization of functions of breaking) of failures of separate pares of PSD with thyristor switch was substantiated. To ensure protection sensitivity to the shunt transformer winding short circuit, in particular, to a short circuit that is not implemented in the current differential protection for PSD with mechanical switch, the differential current protection reacting to the amount of primary ampere-turns of high-voltage and low-voltage winding of this transformer was designed. Studies have shown that the use of differential current cutoff instead of overcurrent protection for the shunt transformer wndings allows one to provide the sensitivity during thyristor failure with the formation of a short circuit. The results of simulation mode for the PSD with switch thyristor designed to be installed as switching point of Voskhod-Tatarskaya-Barabinsk 220 kV transmission line point out the efficiency of the developed solutions that ensure reliable functioning of the PSD.

Limitations imposed by wearing armour on Medieval soldiers' locomotor performance

OpenAIRE

Askew, Graham N.; Formenti, Federico; Minetti, Alberto E.

2011-01-01

In Medieval Europe, soldiers wore steel plate armour for protection during warfare. Armour design reflected a trade-off between protection and mobility it offered the wearer. By the fifteenth century, a typical suit of field armour weighed between 30 and 50 kg and was distributed over the entire body. How much wearing armour affected Medieval soldiers' locomotor energetics and biomechanics is unknown. We investigated the mechanics and the energetic cost of locomotion in armour, and determined...

Method of and device for querying of protected structured data

NARCIS (Netherlands)

Jonker, Willem; Brinkman, Richard; Doumen, J.M.; Schoenmakers, Berry

2005-01-01

Method of and device for querying of protected data structured in the form of a tree. A corresponding tree of node polynomials is constructed such that each node polynomial evaluates to zero for an input equal to an identifier assigned to a node name occurring in a branch of the data tree starting

Method of and device for querying of protected structured data

NARCIS (Netherlands)

Brinkman, Richard; Doumen, J.M.; Jonker, Willem; Schoenmakers, B.

Method of and device for querying of protected data structured in the form of a tree. A corresponding tree of node polynomials is constructed such that each node polynomial evaluates to zero for an input equal to an identifier assigned to a node name occurring in a branch of the data tree starting

Resistance to wear and microstructure of martensitic welds deposits for recharge

International Nuclear Information System (INIS)

Gualco, Agustin; Svoboda, Hernan G; Surian, Estela S; Vedia, Luis A

2006-01-01

This work studied the welding metal for a martensitic steel (alloyed to Cr, Mn, Mo, V and W), deposited with a tubular metal-cored wire with gaseous protection of 82%Ar-18%Co 2 on a low carbon steel using the semi-automatic welding process. Transverse pieces were cut from the welded coupon for microstructural characterization, measurement of hardness profiles, determination of the chemical composition and wear trials. The microstructural characterization was done using optic and scanning electronic microscopes, X-rays diffraction and energy-dispersive X-ray spectroscopy and Vicker microhardness (1 kg.) was measured. The wear trials (metal-metal) were performed in an Amsler machine under pure flow conditions. Different loads were used and the reference material was a SAE 1020 steel. The temperatures for each case were measured and the weight loss curves were defined as a function of the distance run and of the load. After testing the wear surfaces and the debris were measured. The microstructure of the welded deposit mostly consists of martensite and some retained austenite, with a pattern of dendritic segregation, and a hardness on the surface of 612 HVI. A lineal variation between the weight loss and the load applied was obtained as a response to the wear. The following phenomena were observed: abrasion, plastic deformation, oxidation and adhesion to the wear surfaces, as well as a tempering effect in the condition of the biggest load. The wear mechanisms acting on both surfaces were identified (CW)

Innovative measuring system for wear-out indication of high power IGBT modules

DEFF Research Database (Denmark)

Nielsen, Rasmus Ørndrup; Due, Jens; Munk-Nielsen, Stig

2011-01-01

Power converter failures are a major issue in modern Wind turbines. One of the key elements of power converters for high power application is the IGBT modules. A test bench capable of performing an accelerated wear-out test through power cycling of IGBT modules has been made. In the test bench...... it is possible to stress the IGBT module in a real life working point, controlling the voltage, current and phase of the device under test. An analysis of failure mechanisms has been carried out, indicating that VCE can be used as an sign of wear out of the IGBT module. Therefore an innovative measuring system...... for VCE monitoring with an accuracy as low as a few mV has been implemented. The measurements on the IGBT in the test bench show that it is possible to monitor VCE and use this as an indicator of wear-out....

Improving 200 MW NDHR reactor protection system with GAL devices

International Nuclear Information System (INIS)

Shi Mingde; Li Duo; Xie Zhengguo

1999-01-01

The emergence of General Array Logic (GAL), a fairly new type of logic devices with the characteristics of user-definable logic functions, have led to a revolutionary change in the design of logical circuits. The improvements of the reactor protection system for the 200 MW nuclear district heating reactor (NDHR) using GAL are covered

Rapid Analyses of Polyetheretherketone Wear Characteristics by Accelerated Wear Testing with Microfabricated Surfaces for Artificial Joint Systems.

Science.gov (United States)

Su, Chen-Ying; Kuo, Chien-Wei; Fang, Hsu-Wei

2017-01-01

Wear particle-induced biological responses are the major factors resulting in the loosening and then failure of total joint arthroplasties. It is feasible to improve the lubrication and reduce the wear of artificial joint system. Polyetheretherketone (PEEK) is considered as a potential bearing material due to its mechanical characteristics of resistance to fatigue strain. The PEEK wear particles have been indicated to be involved in biological responses in vitro, and further studies regarding the wear phenomena and wear particle generation are needed. In this study, we have established an accelerated wear testing system with microfabricated surfaces. Various contact pressures and lubricants have been utilized in the accelerated wear tests. Our results showed that increasing contact pressure resulted in an increase of wear particle sizes and wear rate, and the size of PEEK wear particles can be controlled by the feature size of microfabricated surfaces. These results provided the information rapidly about factors that affect the morphology and amount of PEEK wear particles and can be applied in the future for application of PEEK on the biological articulation system.

Titanium Carbides Coatings for Wear Resistant Biomedical Devices: Manufacturing and Modeling

International Nuclear Information System (INIS)

Contro, R.; Vena, P.; Gastaldi, D.; Masante, S.; Cavallotti, P. L.; Nobili, L.; Bestetti, M.

2008-01-01

Deposition of Titanium Carbide coatings on Ti6Al4V substrate, through the reactive magnetron sputtering technique is here presented. The mechanical characterization of the coatings has been carried out through a set of indentation tests at different maximum applied loads. The elastic stiffness as well as the hardness of the coating-substrate system indicate that these coatings are suitable candidates for wear resistance applications in the orthopaedic field. Numerical simulation of the indentation tests allowed the identification of the constitutive parameters of the titanium carbide. Good agreement was achieved between experimental and numerical results

Awareness of wearing an accelerometer does not affect physical activity in youth

Directory of Open Access Journals (Sweden)

Jérémy Vanhelst

2017-07-01

Full Text Available Abstract Background This study aimed to investigate whether awareness of being monitored by an accelerometer has an effect on physical activity in young people. Methods Eighty healthy participants aged 10–18 years were randomized between blinded and nonblinded groups. The blinded participants were informed that we were testing the reliability of a new device for body posture assessment and these participants did not receive any information about physical activity. In contrast, the nonblinded participants were informed that the device was an accelerometer that assessed physical activity levels and patterns. The participants were instructed to wear the accelerometer for 4 consecutive days (2 school days and 2 school-free days. Results Missing data led to the exclusion of 2 participants assigned to the blinded group. When data from the blinded group were compared with these from the nonblinded group, no differences were found in the duration of any of the following items: (i wearing the accelerometer, (ii total physical activity, (iii sedentary activity, and (iv moderate-to-vigorous activity. Conclusions Our study shows that the awareness of wearing an accelerometer has no influence on physical activity patterns in young people. This study improves the understanding of physical activity assessment and underlines the objectivity of this method. Trial registration NCT02844101 (retrospectively registered at July 13th 2016.

Dry Sliding Wear Behavior of Spark Plasma Sintered Fe-Based Bulk Metallic Glass/Graphite Composites

Directory of Open Access Journals (Sweden)

Xiulin Ji

2016-09-01

Full Text Available Bulk metallic glass (BMG and BMG-graphite composites were fabricated using spark plasma sintering at the sintering temperature of 575 °C and holding time of 15 min. The sintered composites exhibited partial crystallization and the presence of distributed porosity and graphite particles. The effect of graphite reinforcement on the tribological properties of the BMG/graphite composites was investigated using dry ball-on-disc sliding wear tests. The reinforcement of graphite resulted in a reduction in both the wear rate and the coefficient of friction as compared to monolithic BMG samples. The wear surfaces of BMG/graphite composites showed regions of localized wear loss due to microcracking and fracture, as was also the case with the regions covered with graphite-rich protective film due to smearing of pulled off graphite particles.

Effect of Volume Fraction of Particle on Wear Resistance of Al2O3/Steel Composites at Elevated Temperature

Institute of Scientific and Technical Information of China (English)

BAO Chong-gao; WANG En-ze; GAO Yi-min; XING Jian-dong

2005-01-01

Based on previous work,abrasive wear resistance of Al2 O3/steel composites with different Al2 O3 parti cle volume fraction (VOF) at 900 C was investigated.The experimental results showed that a suitable particle VOF is important to protect the metal matrix from wear at elevated temperature.Both too high and too low particle VOF lead to a poor abrasive wear because a bulk matrix is easily worn off by grits when it exceeds the suitable VOF and also because when VOF is low,the Al2O3 particles are easily dug out by grits during wearing as well.When the particle VOF is 39%,the wear resistance of tested composites is excellent.

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

Modeling of wear behavior of Al/B_4C composites produced by powder metallurgy

International Nuclear Information System (INIS)

Sahin, Ismail; Bektas, Asli; Guel, Ferhat; Cinci, Hanifi

2017-01-01

Wear characteristics of composites, Al matrix reinforced with B_4C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B_4C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

Friction and wear performance of diamond-like carbon, boron carbide, and titanium carbide coatings against glass

International Nuclear Information System (INIS)

Daniels, B.K.; Brown, D.W.; Kimock, F.M.

1997-01-01

Protection of glass substrates by direct ion beam deposited diamond-like carbon (DLC) coatings was observed using a commercial pin-on-disk instrument at ambient conditions without lubrication. Ion beam sputter-deposited titanium carbide and boron carbide coatings reduced sliding friction, and provided tribological protection of silicon substrates, but the improvement factor was less than that found for DLC. Observations of unlubricated sliding of hemispherical glass pins at ambient conditions on uncoated glass and silicon substrates, and ion beam deposited coatings showed decreased wear in the order: uncoated glass>uncoated silicon>boron carbide>titanium carbide>DLC>uncoated sapphire. Failure mechanisms varied widely and are discussed. Generally, the amount of wear decreased as the sliding friction decreased, with the exception of uncoated sapphire substrates, for which the wear was low despite very high friction. There is clear evidence that DLC coatings continue to protect the underlying substrate long after the damage first penetrates through the coating. The test results correlate with field use data on commercial products which have shown that the DLC coatings provide substantial extension of the useful lifetime of glass and other substrates. copyright 1997 Materials Research Society

Corrosion and corrosion protection of support structures for offshore wind energy devices (OWEA)

Energy Technology Data Exchange (ETDEWEB)

Momber, A. [Muehlhan AG, Schlinckstrasse 3, D-21107 Hamburg (Germany)

2011-05-15

The paper provides a review about the corrosion and corrosion protection of offshore wind energy devices (OWEA). Firstly, special features resulting from location and operation of OWEA are being discussed. Secondly, types of corrosion and corrosion phenomena are summarized in a systematic way. Finally, practical solutions to the corrosion protection of OWEA, including steel allowances, cathodic protection and coatings and linings, are discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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.

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...

Biomechanics of the immediate impact of wearing a rigid thoracolumbar corset on gait kinematics and spatiotemporal parameters

Directory of Open Access Journals (Sweden)

Taiar Redha

2018-01-01

Full Text Available The corset support is a device classified as orthosis. It compensates a functional deficiency with means of protection, recovery, correction, maintenance, and support or contention. There are two types of orthosis 1 rest orthosis and 2 corrective orthosis. Rest orthosis maintains joints in a defined position to avoid deformities or to relieve a pain at joints. Corrective orthosis adjusts joint deformity either passively or actively. Corset is used in various pathological use, thoracic-lumbar fracture, scoliosis, Scheuermann’s disease or spinal dystrophy. The purpose of this study was 1 to determine the immediate impact of wearing a semi-rigid thoracolumbar corset, the Lombax® Dorso on gait kinematics and 2 spatiotemporal parameters in 6 adults. These parameters were recorded using the optoelectronic system Vicon® on treadmill gait subjects with and without corset for the comparison. The results showed that wearing a corset significantly decrease the rotation amplitudes of the scapular and pelvic girdles (p<0.05 in the frontal plane. The movement of the pelvis and hip in this same plane was decreased also when comparing with and without a corset effects (p<0.05. The corset significantly increased the range of flexion-extension of the hip during the gait cycle. At the conclusion of this study the discriminate parameters of wearing a corset was quantified. The results and in association with manufacturer will help to improve materials for better optimization support. Comparable perspectives and after improvement of materials will aim to experiment with patients on real daily life situation.

The use of hearing protection devices with approach risk perception of noise induced hearing loss in several manufacturing industry

Directory of Open Access Journals (Sweden)

Behzad Fouladi Deahghi

2015-06-01

Full Text Available Background & Objective : Noise is a widespread physical agent and although is a most risk factors in workplaces that workers of health to exposed. Thus, different actions is done for reduce exposure to it in work places, which one of them is use of hearing protection devices. The use of hearing protection devices with approach risk perception of noise induced hearing loss in several manufacturing industry Method: This study was Cross-sectional study and done in five industrial unit with a sound pressure level more of 85 dB-A with the participation of 340 workers. To collect data , individual risk perception and self-investigator questionnaires were used. After collecting data, statistical analysis including Cronbach's alpha and regression were used to analyze the data. Results : Range use of hearing protection devices during shifts work by workers, respectively equal to: 50.4% sometimes, 31.58% never and 18.2% at all times. Also, results indicate significant differences between individual differences and hearing protection devices. Conclusion : Results of this study showed that individual risk perception as an important factor, can do a significant role in predicting the behavior of personals in the use of hearing protection devices, which should be considered in any design and implementation of hearing protection program.

Friction, adhesion and wear properties of PDMS films on silicon sidewalls

International Nuclear Information System (INIS)

Penskiy, I; Gerratt, A P; Bergbreiter, S

2011-01-01

This paper demonstrates the first tests of friction, adhesion and wear properties of thin poly(dimethylsiloxane) (PDMS) films on the sidewalls of silicon-on-insulator structures. The test devices were individually calibrated using a simple method that included optical and electrical measurements. The static coefficient of friction versus normal pressure curves were obtained for PDMS–PDMS, PDMS–silicon and silicon–silicon sidewall interfaces. The effects of aging on friction and adhesion properties of PDMS were also evaluated. The results of friction tests showed that the static coefficient of friction follows the JKR contact model, which means that the friction force depends on the apparent area of contact. The wear tests showed high resistance of PDMS to abrasion over millions of cycles.

Research and development to protect soldiers from landmines and improvised explosive devices

CSIR Research Space (South Africa)

Ahmed, R

2015-10-01

Full Text Available Landmines and Improvised Explosive Devices (IEDs) remain a major threat for military vehicles, their occupants and other assets. It is thus imperative that traditional methods of protection need to be adapted or new technologies developed....

76 FR 20840 - Medical Devices; General and Plastic Surgery Devices; Classification of the Low Level Laser...

Science.gov (United States)

2011-04-14

... looking directly at the laser beam and the wearing of appropriate laser safety eyewear by both the user...). The special control for this device is the FDA guidance document entitled ``Guidance for Industry and...

Friction and wear in hot forging of steels

International Nuclear Information System (INIS)

Daouben, E.; Dubar, L.; Dubar, M.; Deltombe, R.; Dubois, A.; Truong-Dinh, N.; Lazzarotto, L.

2007-01-01

In the field of hot forging of steels, the mastering of wear phenomena enables to save cost production, especially concerning tools. Surfaces of tools are protected thanks to graphite. The existing lubrication processes are not very well known: amount and quality of lubricant, lubrication techniques have to be strongly optimized to delay wear phenomena occurrence. This optimization is linked with hot forging processes, the lubricant layers must be tested according to representative friction conditions. This paper presents the first part of a global study focused on wear phenomena encountered in hot forging of steels. The goal is the identification of reliable parameters, in order to bring knowledge and models of wear. A prototype testing stand developed in the authors' laboratory is involved in this experimental analysis. This test is called Warm and Hot Upsetting Sliding Test (WHUST). The stand is composed of a heating induction system and a servo-hydraulic system. Workpieces taken from production can be heated until 1200 deg. C. A nitrided contactor representing the tool is heated at 200 deg. C. The contactor is then coated with graphite and rubs against the workpiece, leaving a residual track on it. Friction coefficient and surface parameters on the contactor and the workpiece are the most representative test results. The surface parameters are mainly the sliding length before defects occurrence, and the amplitude of surface profile of the contactor. The developed methodology will be first presented followed by the different parts of the experimental prototype. The results of experiment show clearly different levels of performance according to different lubricants

Radioisotopic measurement methods for determining the wear railway brake shoe and its rim wearing effect

International Nuclear Information System (INIS)

Doman, P.

1979-01-01

Under operating conditions the wear of brake shoe was tested by a measuring method based on the principle of radioisotopic thickness measurement. It is characteristic to the sensitivity of the method that the wear caused by the fast braking of a train (speed: 100 km/h) as well as the uneven wear distribution were determinable. Surface activating methods assuring the periodic and continuous evaluation were also developed. A test was performed with galvanic surface activation under operating conditions to determine the rim wearing effect of the brake shoe. Apart from the operational tests a new method based on activated wear measurement was also developed. (author)

Research on the effect of wear-ring clearances to the axial and radial force of a centrifugal pump

International Nuclear Information System (INIS)

Zhao, W G; Qi, C X; Li, Y B; He, M Y

2013-01-01

Varying of the wear-ring clearance not only has a distinct effect on the volumetric loss of the centrifugal pump, but also on the performance of the centrifugal pump including the axial and radial forces. Comparing with the experimental studies, numerical simulation methods have some special advantages, such as the low cost, fast and high efficiency, and convenient to get the detailed structure of the internal flow characteristics, so it has been widely used in the fluid machinery study in recent years. In order to study the effect of wear-ring clearance on the force performance of the centrifugal pump, based on the Reynolds Time-Averaged N-S equations and RNG k-ε turbulence model, a centrifugal pump with three variable styles of the wear-rings was simulated: Only the clearance of the front wear-ring was changed, only the clearance of the back wear-ring was changed and both were changed. Comparing with the experiment, numerical results show a good agreement. In the three changing styles of the clearance, the variable of the clearance of front wear-ring has the most influence on the axial force of the centrifugal pump, while has tiny effect on the radial force for all the conditions

33 CFR 142.39 - Respiratory protection.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Respiratory protection. 142.39... Respiratory protection. (a) Personnel in an atmosphere specified under ANSI Z88.2, requiring the use of respiratory protection equipment shall wear the type of respiratory protection equipment specified in ANSI Z88...

Intercomparison of radiation protection protection devices in a high-energy stray neutron field. Part III: Instrument response

Czech Academy of Sciences Publication Activity Database

Silari, M.; Agosteo, S.; Beck, P.; Bedogni, R.; Cale, E.; Caresana, M.; Domingo, C.; Donadille, L.; Dubourg, N.; Esposito, A.; Fehrenbacher, G.; Fernández, F.; Ferrarini, M.; Fiechtner, A.; Fuchs, A.; García, M. J.; Golnik, N.; Gutermuth, F.; Khurana, S.; Klages, T.; Latocha, M.; Mares, V.; Mayer, S.; Radon, T.; Reithmeier, H.; Rollet, S.; Roos, H.; Rühm, W.; Sandri, S.; Schardt, D.; Simmer, G.; Spurný, František; Trompier, F.; Villa-Grasa, C.; Weitzenegger, E.; Wiegel, B.; Wielunski, M.; Wissmann, F.; Zechner, A.; Zielczyński, M.

2009-01-01

Roč. 44, 7-8 (2009), s. 673-691 ISSN 1350-4487 R&D Projects: GA AV ČR IAA100480902 Institutional research plan: CEZ:AV0Z10480505 Keywords : radiation protection devices * radiation field * detectors * dosemeters Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.973, year: 2009

Privacy Protection for Personal Health Device Communication and Healthcare Building Applications

Directory of Open Access Journals (Sweden)

Soon Seok Kim

2014-01-01

Full Text Available This paper proposes a new method for protecting patient privacy when communicating with a gateway which collects bioinformation through using personal health devices, a type of biosensor for telemedicine, at home and in other buildings. As the suggested method is designed to conform with ISO/IEEE 11073-20601, which is the international standard, interoperability with various health devices was considered. We believe it will be a highly valuable resource for dealing with basic data because it suggests an additional standard for security with the Continua Health Alliance or related international groups in the future.

Modeling of wear behavior of Al/B{sub 4}C composites produced by powder metallurgy

Energy Technology Data Exchange (ETDEWEB)

Sahin, Ismail; Bektas, Asli [Gazi Univ., Ankara (Turkey). Dept. of Industrial Design Engineering; Guel, Ferhat; Cinci, Hanifi [Gazi Univ., Ankara (Turkey). Dept. of Materials and Metallurgy Engineering

2017-06-01

Wear characteristics of composites, Al matrix reinforced with B{sub 4}C particles percentages of 5, 10,15 and 20 produced by the powder metallurgy method were studied in this study. For this purpose, a mixture of Al and B{sub 4}C powders were pressed under 650 MPa pressure and then sintered at 635 C. The analysis of hardness, density and microstructure was performed. The produced samples were worn using a pin-on-disk abrasion device under 10, 20 and 30 N load through 500, 800 and 1200 mesh SiC abrasive papers. The obtained wear values were implemented in an artificial neural network (ANN) model having three inputs and one output using feed forward backpropagation Levenberg-Marquardt algorithm. Thus, the optimum wear conditions and hardness values were determined.

Quality control methods in accelerometer data processing: defining minimum wear time.

Directory of Open Access Journals (Sweden)

Carly Rich

Full Text Available BACKGROUND: When using accelerometers to measure physical activity, researchers need to determine whether subjects have worn their device for a sufficient period to be included in analyses. We propose a minimum wear criterion using population-based accelerometer data, and explore the influence of gender and the purposeful inclusion of children with weekend data on reliability. METHODS: Accelerometer data obtained during the age seven sweep of the UK Millennium Cohort Study were analysed. Children were asked to wear an ActiGraph GT1M accelerometer for seven days. Reliability coefficients(r of mean daily counts/minute were calculated using the Spearman-Brown formula based on the intraclass correlation coefficient. An r of 1.0 indicates that all the variation is between- rather than within-children and that measurement is 100% reliable. An r of 0.8 is often regarded as acceptable reliability. Analyses were repeated on data from children who met different minimum daily wear times (one to 10 hours and wear days (one to seven days. Analyses were conducted for all children, separately for boys and girls, and separately for children with and without weekend data. RESULTS: At least one hour of wear time data was obtained from 7,704 singletons. Reliability increased as the minimum number of days and the daily wear time increased. A high reliability (r = 0.86 and sample size (n = 6,528 was achieved when children with ≥ two days lasting ≥10 hours/day were included in analyses. Reliability coefficients were similar for both genders. Purposeful sampling of children with weekend data resulted in comparable reliabilities to those calculated independent of weekend wear. CONCLUSION: Quality control procedures should be undertaken before analysing accelerometer data in large-scale studies. Using data from children with ≥ two days lasting ≥10 hours/day should provide reliable estimates of physical activity. It's unnecessary to include only children

Respiratory protective device design using control system techniques

Science.gov (United States)

Burgess, W. A.; Yankovich, D.

1972-01-01

The feasibility of a control system analysis approach to provide a design base for respiratory protective devices is considered. A system design approach requires that all functions and components of the system be mathematically identified in a model of the RPD. The mathematical notations describe the operation of the components as closely as possible. The individual component mathematical descriptions are then combined to describe the complete RPD. Finally, analysis of the mathematical notation by control system theory is used to derive compensating component values that force the system to operate in a stable and predictable manner.

Protective equipment use among female rugby players.

Science.gov (United States)

Comstock, R Dawn; Fields, Sarah K; Knox, Christy L

2005-07-01

Our objective was to assess the prevalence of protective equipment use and the motivation for using protective equipment among a sample of US female rugby players. We surveyed a convenience sample of 234 current US female rugby players from 14 teams participating in a US women's rugby tournament, obtaining self-reported demographic, rugby exposure, and protective equipment use information. Mouthguards were the most commonly used piece of protective equipment: 90.8% of players reported having always worn a mouthguard while playing or practicing rugby within their most recent 3 months of play. Fewer than 15% of players reported having always worn other types of protective equipment. Equipment use varied by playing position. Whereas over 80% of players in all other positions always wore a mouthguard, 66.7% of scrum halves reported always wearing one. Both backs and forwards reported wearing shoulder pads, but only forwards reported always wearing padded headgear. Mouthguards, padded headgear, and shoulder pads were worn "to prevent injury," whereas ankle braces, neoprene sleeves, and athletic tape on joints were worn "to protect a current/recent injury." This is the first study of female rugby players to assess the prevalence of protective equipment use by playing position and the motivation for using protective equipment. With the exception of mouthguards, US female rugby players infrequently use protective equipment. Protective equipment use varies by playing position. Some types of protective equipment appear to be used as primary prevention mechanisms, whereas others are used as secondary or tertiary prevention mechanisms.

Wear resistance analysis of the aluminum 7075 alloy and the nanostructured aluminum 7075 - silver nanoparticles composites

Directory of Open Access Journals (Sweden)

Estrada-Ruiz R.H.

2016-01-01

Full Text Available Nanostructured composites of the aluminum 7075 alloy and carbon-coated silver nanoparticles were synthetized by the mechanical milling technique using a high-energy mill SPEX 8000M; the powders generated were compacted, sintered and hot-extruded to produce 1 cm-diameter bars. The composites were then subjected to a wear test using a pin-on-disc device to validate the hypothesis that second phase-ductile nanometric particles homogenously distributed throughout the metalmatrix improve the wear resistance of the material. It was found that silver nanoparticles prevent the wear of the material by acting as an obstacle to dislocations movement during the plastic deformation of the contact surface, as well as a solid lubricant when these are separated from the metal-matrix.

Carbon based prosthetic devices

Energy Technology Data Exchange (ETDEWEB)

Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine

1998-12-31

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

A novel mechanical design of broken rope protection device for enhancing the safety performances of overhead manned equipment in coal mine

Directory of Open Access Journals (Sweden)

Xiaoguang Zhang

2015-08-01

Full Text Available A novel mechanical design of the broken rope protection device is proposed to enhance the safety performances of the overhead manned equipment. According to the operating characteristics and functional requirements of the overhead manned equipment, a three-dimensional mechanical model of the broken rope protection device was redesigned. Based on the known parameters of the mechanical model, the stress and strength of the main components are readjusted using the statics characteristics of finite element analysis. To ensure the reliability of the control system of the broken rope protection device, the process of people’s falling, the response performance of the tension sensor, and the signal extraction of the broken rope are analyzed under different loading and unloading speeds. The working principle of the broken rope protection device is expounded in detail. The experimental results showed that better effect is obtained by the new broken rope protection device, which is characterized by good durability, low investment, and high reliability.

49 CFR 214.115 - Foot protection.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Foot protection. 214.115 Section 214.115... protection. (a) The railroad or railroad contractor shall require railroad bridge workers to wear foot protection equipment when potential foot injury may result from impact, falling or flying objects, electrical...

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.

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

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

Wear measurement of dental tissues and materials in clinical studies: A systematic review.

Science.gov (United States)

Wulfman, C; Koenig, V; Mainjot, A K

2018-06-01

This study aims to systematically review the different methods used for wear measurement of dental tissues and materials in clinical studies, their relevance and reliability in terms of accuracy and precision, and the performance of the different steps of the workflow taken independently. An exhaustive search of clinical studies related to wear of dental tissues and materials reporting a quantitative measurement method was conducted. MedLine, Embase, Scopus, Cochrane Library and Web of Science databases were used. Prospective studies, pilot studies and case series (>10 patients), as long as they contained a description of wear measurement methodology. Only studies published after 1995 were considered. After duplicates' removal, 495 studies were identified, and 41 remained for quantitative analysis. Thirty-four described wear-measurement protocols, using digital profilometry and superimposition, whereas 7 used alternative protocols. A specific form was designed to analyze the risk of bias. The methods were described in terms of material analyzed; study design; device used for surface acquisition; matching software details and settings; type of analysis (vertical height-loss measurement vs volume loss measurement); type of area investigated (entire occlusal area or selective areas); and results. There is a need of standardization of clinical wear measurement. Current methods exhibit accuracy, which is not sufficient to monitor wear of restorative materials and tooth tissues. Their performance could be improved, notably limiting the use of replicas, using standardized calibration procedures and positive controls, optimizing the settings of scanners and matching softwares, and taking into account unusable data. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Determination of rail wear and short-time wear measurements of rails applying radioisotopes

International Nuclear Information System (INIS)

Grohmann, H.D.

1981-01-01

An energetic model has been developed for calculating rail wear. Short-time wear tests on rails after surface activation and following activity measurements showed a good agreement with the calculated values

Transcranial Doppler monitoring during stenting of the carotid bifurcation: evaluation of two different distal protection devices in preventing embolization.

Science.gov (United States)

Rubartelli, Paolo; Brusa, Giulia; Arrigo, Alessandro; Abbadessa, Francesco; Giachero, Corinna; Vischi, Massimo; Ricca, Maria Maddalena; Ottonello, Gian Andrea

2006-08-01

To compare the efficacy of 2 emboli protection devices in preventing embolization during carotid artery stenting (CAS). The GuardWire distal occlusion system (n=19) and the distal FilterWire EX (n=12) were compared in 31 consecutive patients (24 men; mean age 71+/-10 years) monitored with transcranial Doppler for microembolic signals before, during, and after CAS. The choice of the protection device was based on availability and on the patency of the contralateral carotid artery. The baseline characteristics were similar in the patients treated under protection from either device. Placement and retrieval of the protection device, stenting, and postdilation were technically successful in all patients. Two patients suffered a transient ischemic attack shortly after the procedure; no other adverse cardiovascular events occurred at 30 days. Compared to the GuardWire, the use of the FilterWire was associated with more microembolic signals during stent deployment (77.4+/-33.5 versus 1.07+/-1.94, pprotection device (21.4+/-15.4 versus 10.9+/-8.3, p=0.051). Consequently, the total amount of microembolic signals during the procedure was higher when the filter device was employed (183.0+/-42.1 versus 31.7+/-12.0, p<0.0001). The distal occlusion device appears to be more effective than the filter in reducing distal embolization detected by transcranial Doppler monitoring.

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

30 CFR 57.15004 - Eye protection.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Eye protection. 57.15004 Section 57.15004... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Personal Protection Surface and Underground § 57.15004 Eye protection. All persons shall wear safety glasses, goggles, or face...

30 CFR 56.15003 - Protective footwear.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protective footwear. 56.15003 Section 56.15003 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE....15003 Protective footwear. All persons shall wear suitable protective footwear when in or around an area...

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

Wear Analysis of Top Piston Ring to Reduce Top Ring Reversal Bore Wear

Directory of Open Access Journals (Sweden)

P. Ilanthirayan

2017-12-01

Full Text Available The piston rings are the most important part in engine which controls the lubricating oil consumption and blowby of the gases. The lubricating film of oil is provided to seal of gases towards crankcase and also to give smooth friction free translatory motion between rings and liner. Of the three rings present top ring is more crucial as it does the main work of restricting gases downwards the crankcase. Boundary lubrication is present at the Top dead centre (TDC and Bottom dead centre (BDC of the liner surface. In addition to this, top ring is exposed to high temperature gases which makes the oil present near the top ring to get evaporated and decreasing its viscosity, making metal-metal contact most of the time. Due to this at TDC, excess wear happens on the liner which is termed as Top ring reversal bore wear. The wear rate depends upon many parameters such as lubrication condition, viscosity index, contact type, normal forces acting on ring, geometry of ring face, surface roughness, material property. The present work explores the wear depth for different geometries of barrel ring using Finite Element model with the help of Archard wear law and the same is validated through experimentation. The study reveals that Asymmetric barrel rings have less contact pressure which in turn reduces the wear at Top dead centre.

Wear mechanisms in ceramic hip implants.

Science.gov (United States)

Slonaker, Matthew; Goswami, Tarun

2004-01-01

The wear in hip implants is one of the main causes for premature hip replacements. The wear affects the potential life of the prosthesis and subsequent removals of in vivo implants. Therefore, the objective of this article is to review various joints that show lower wear rates and consequently higher life. Ceramics are used in hip implants and have been found to produce lower wear rates. This article discusses the advantages and disadvantages of ceramics compared to other implant materials. Different types of ceramics that are being used are reviewed in terms of the wear characteristics, debris released, and their size together with other biological factors. In general, the wear rates in ceramics were lower than that of metal-on-metal and metal-on-polyethylene combinations.

Remote controlled stud bolt handling device for reactor pressure vessel

International Nuclear Information System (INIS)

Shindo, Takenori; Shigehiro, Katsuya; Ito, Morio; Okada, Kenji

1988-01-01

In nuclear power stations, at the time of regular inspection, the works of opening and fixing the upper covers of reactor pressure vessels are carried out for inspecting the inside of reactor pressure vessels and exchanging fuel rods. These upper covers are fastened with many stud bolts, therefore, the works of opening and fixing require a large amount of labor, and are done under the restricted condition of wearing protective clothings and masks. Babcock Hitachi K.K. has completed the development of a remotely controlled automatic bolt tightenig device for this purpose, therefore, its outline is reported. The conventional method of these works and the problems in it are described. The design of the new device aimed at the parallel execution of cleaning screw threads, loosening and tightening nuts, and taking off and putting on nuts and washers, thus contributing to the shortening of regular inspection period, the reduction of the radiation exposure of workers, and the decrease of the number of workers. The function, reliability and endurance of the new device were confirmed by the verifying test using a device made for trial. The device is composed of a stand, a rail and four stations each with a cleaning unit, a stud tensioner and a nut handling unit. (K.I.)

Wear of control rod cluster assemblies and of instrumentation thimbles: first results obtained with the vibrateau wear simulator

International Nuclear Information System (INIS)

Zbinden, M.; Hersant, D.

1993-07-01

Several REP components are affected by a particular sort of damage called impact/sliding wear. This kind of wear, originating from flow induced vibrations, affects loosely supported tubular structures. The main involved components are: - the RCCAs claddings and the guides tubes, - the instrumentation thimbles, - the fuel rods claddings, - the SG tubes. The R and D Division is concerned with studies aiming to understand and to master the phenomena leading to this wear. The MTC Branch is charged of the study of the wear itself. Tests are carried out on wear rigs to understand and to model wear mechanisms. The following work is related to the two first wear tests campaigns on the VIBRATEAU wear simulator: - a reproducibility test series in order to assess the spreading of the experimental results, - a comparative test series on surface treatments used to improve the components war resistance. (authors). 7 figs., 2 tabs., 4 refs

Energy and wear optimisation of train longitudinal dynamics and of traction and braking systems

Science.gov (United States)

Conti, R.; Galardi, E.; Meli, E.; Nocciolini, D.; Pugi, L.; Rindi, A.

2015-05-01

Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components.

Nitrogen plasma immersion ion implantation for surface treatment and wear protection of austenitic stainless steel X6CrNiTi1810

International Nuclear Information System (INIS)

Blawert, C.; Mordike, B.L.

1999-01-01

Plasma immersion ion implantation is an effective surface treatment for stainless steels. The influence of treatment parameters (temperature, plasma density and pressure) on the sliding wear resistance are studied here. At moderate temperatures, nitrogen remains in solid solution without forming nitrides. This increases the surface hardness and the wear resistance without affecting the passivation of the steel. This may allow the use of such steels in applications where their poor wear resistance would normally prohibit their use. (orig.)

Effects of Load and Speed on Wear Rate of Abrasive Wear for 2014 Al Alloy

Science.gov (United States)

Odabas, D.

2018-01-01

In this paper, the effects of the normal load and sliding speed on wear rate of two-body abrasive wear for 2014 Al Alloy were investigated in detail. In order to understand the variation in wear behaviour with load and speed, wear tests were carried out at a sliding distance of 11 m, a speed of 0.36 m/s, a duration of 30 s and loads in the range 3-11 N using 220 grit abrasive paper, and at a speed range 0.09-0.90 m/s, a load of 5 N and an average sliding distance of 11 m using abrasive papers of 150 grit size under dry friction conditions. Before the wear tests, solution treatment of the 2014 Al alloy was carried out at temperatures of 505 and 520 °C for 1 h in a muffle furnace and then quenched in cold water at 15 °C. Later, the ageing treatment was carried out at 185 °C for 8 h in the furnace. Generally, wear rate due to time increased linearly and linear wear resistance decreased with increasing loads. However, the wear rate was directly proportional to the load up to a critical load of 7 N. After this load, the slope of the curves decreased because the excessive deformation of the worn surface and the instability of the abrasive grains began to increase. When the load on an abrasive grain reaches a critical value, the groove width is about 0.17 of the abrasive grain diameter, and the abrasive grains begin to fail. The wear rate due to time increased slightly as the sliding speed increased in the range 0.09-0.90 m/s. The reason for this is that changes arising from strain rate and friction heating are expected with increasing sliding speeds.

Ultrananocrystalline diamond film as a wear resistant and protective coating for mechanical seal applications

International Nuclear Information System (INIS)

Sumant, A.V.; Krauss, A.R.; Gruen, D.M.; Auciello, O.; Erdemir, A.; Williams, M.; Artiles, A.F.; Adams, W.

2005-01-01

Mechanical shaft seals used in pumps are critically important to the safe operation of the paper, pulp, and chemical process industry, as well as petroleum and nuclear power plants. Specifically, these seals prevent the leakage of toxic gases and hazardous chemicals to the environment and final products from the rotating equipment used in manufacturing processes. Diamond coatings have the potential to provide negligible wear, ultralow friction, and high corrosion resistance for the sliding surfaces of mechanical seals, because diamond exhibits outstanding tribological, physical, and chemical properties. However, diamond coatings produced by conventional chemical vapor deposition (CVD) exhibit high surface roughness (R a ≥ 1 μm), which results in high wear of the seal counterface, leading to premature seal failure. To avoid this problem, we have developed an ultrananocrystalline diamond (UNCD) film formed by a unique CH 4 /Ar microwave plasma CVD method. This method yields extremely smooth diamond coatings with surface roughness R a = 20-30 nm and an average grain size of 2-5 nm. We report the results of a systematic test program involving uncoated and UNCD-coated SiC shaft seals. Results confirmed that the UNCD-coated seals exhibited neither measurable wear nor any leakage during long-duration tests that took 21 days to complete. In addition, the UNCD coatings reduced the frictional torque for seal rotation by five to six times compared with the uncoated seals. This work promises to lead to rotating shaft seals with much improved service life, reduced maintenance cost, reduced leakage of environmentally hazardous materials, and increased energy savings. This technology may also have many other tribological applications involving rolling or sliding contacts.

30 CFR 56.15004 - Eye protection.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Eye protection. 56.15004 Section 56.15004... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Personal Protection § 56.15004 Eye protection. All persons shall wear safety glasses, goggles, or face shields or other suitable...

Characterization of wear debris from metal-on-metal hip implants during normal wear versus edge-loading conditions.

Science.gov (United States)

Kovochich, Michael; Fung, Ernest S; Donovan, Ellen; Unice, Kenneth M; Paustenbach, Dennis J; Finley, Brent L

2018-04-01

Advantages of second-generation metal-on-metal (MoM) hip implants include low volumetric wear rates and the release of nanosized wear particles that are chemically inert and readily cleared from local tissue. In some patients, edge loading conditions occur, which result in higher volumetric wear. The objective of this study was to characterize the size, morphology, and chemistry of wear particles released from MoM hip implants during normal (40° angle) and edge-loading (65° angle with microseparation) conditions. The mean primary particle size by volume under normal wear was 35 nm (range: 9-152 nm) compared with 95 nm (range: 6-573 nm) under edge-loading conditions. Hydrodynamic diameter analysis by volume showed that particles from normal wear were in the nano- (edge-loading conditions generated particles that ranged from Edge-loading conditions generated more elongated particles (4.5%) (aspect ratio ≥ 2.5) and more CoCr alloy particles (9.3%) compared with normal wear conditions (1.3% CoCr particles). By total mass, edge-loading particles contained approximately 640-fold more cobalt than normal wear particles. Our findings suggest that high wear conditions are a potential risk factor for adverse local tissue effects in MoM patients who experience edge loading. This study is the first to characterize both the physical and chemical characteristics of MoM wear particles collected under normal and edge-loading conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 986-996, 2018. © 2017 Wiley Periodicals, Inc.

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.

Electrodeposition of diamond-like carbon films on titanium alloy using organic liquids: Corrosion and wear resistance

International Nuclear Information System (INIS)

Falcade, Tiago; Shmitzhaus, Tobias Eduardo; Gomes dos Reis, Otávio; Vargas, André Luis Marin; Hübler, Roberto; Müller, Iduvirges Lourdes; Fraga Malfatti, Célia de

2012-01-01

Highlights: ► The electrodeposition may be conducted at room temperature. ► The DLC films have good resistance to corrosion in saline environments. ► The films have lower coefficient of friction than the uncoated substrate. ► The abrasive wear protection is evident in coated systems. - Abstract: Diamond-like carbon (DLC) films have been studied as coatings for corrosion protection and wear resistance because they have excellent chemical inertness in traditional corrosive environments, besides presenting a significant reduction in coefficient of friction. Diamond-like carbon (DLC) films obtained by electrochemical deposition techniques have attracted a lot of interest, regarding their potential in relation to the vapor phase deposition techniques. The electrochemical deposition techniques are carried out at room temperature and do not need vacuum system, making easier this way the technological transfer. At high electric fields, the organic molecules polarize and react on the electrode surface, forming carbon films. The aim of this work was to obtain DLC films onto Ti6Al4V substrate using as electrolyte: acetonitrile (ACN) and N,N-dimethylformamide (DMF). The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectroscopy, potentiodynamic polarization and wear tests. The results show that these films can improve, significantly, the corrosion resistance of titanium and its alloys and their wear resistance.

Use of dentifrices to prevent erosive tooth wear: harmful or helpful?

Directory of Open Access Journals (Sweden)

Ana Carolina Magalhães

2014-01-01

Full Text Available Dental erosion is the loss of dental hard tissues caused by non-bacterial acids. Due to acid contact, the tooth surface becomes softened and more prone to abrasion from toothbrushing. Dentifrices containing different active agents may be helpful in allowing rehardening or in increasing surface resistance to further acidic or mechanical impacts. However, dentifrices are applied together with brushing and, depending on how and when toothbrushing is performed, as well as the type of dentifrice and toothbrush used, may increase wear. This review focuses on the potential harmful and helpful effects associated with the use of dentifrices with regard to erosive wear. While active ingredients like fluorides or agents with special anti-erosive properties were shown to offer some degree of protection against erosion and combined erosion/abrasion, the abrasive effects of dentifrices may increase the surface loss of eroded teeth. However, most evidence to date comes from in vitro and in situ studies, so clinical trials are necessary for a better understanding of the complex interaction of active ingredients and abrasives and their effects on erosive tooth wear.

Wear of rolling element bearings in sodium

International Nuclear Information System (INIS)

Campbell, C.S.

1976-01-01

Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

Gear Tooth Wear Detection Algorithm

Science.gov (United States)

Delgado, Irebert R.

2015-01-01

Vibration-based condition indicators continue to be developed for Health Usage Monitoring of rotorcraft gearboxes. Testing performed at NASA Glenn Research Center have shown correlations between specific condition indicators and specific types of gear wear. To speed up the detection and analysis of gear teeth, an image detection program based on the Viola-Jones algorithm was trained to automatically detect spiral bevel gear wear pitting. The detector was tested using a training set of gear wear pictures and a blind set of gear wear pictures. The detector accuracy for the training set was 75 percent while the accuracy for the blind set was 15 percent. Further improvements on the accuracy of the detector are required but preliminary results have shown its ability to automatically detect gear tooth wear. The trained detector would be used to quickly evaluate a set of gear or pinion pictures for pits, spalls, or abrasive wear. The results could then be used to correlate with vibration or oil debris data. In general, the program could be retrained to detect features of interest from pictures of a component taken over a period of time.

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

Wear mechanisms of toughened zirconias

International Nuclear Information System (INIS)

Becker, P.C.; Libsch, T.A.; Rhee, S.K.

1985-01-01

The dry friction and wear behavior of toughened zirconias against hardened steel was studied using the falex ring and block technique. Three experimental ZrO 2 -Y 2 O 3 ceramics and two commerical ZrO 2 -MgO ceramics were investigated. Each ceramic was tested at 500 and 2000 rpm at normal loads in the range 2.3 to 40.8 kg. Significant trends in the friction and wear data were found correlating composition, test speeds, and loads. Microstructural examination of the ring, ceramic block, and wear debris has shown that the wear process is very complex and incorporates a number of mechanisms

Effect of work material composition on the wear life of TiN-coated tools

Energy Technology Data Exchange (ETDEWEB)

Harju, E. [Helsinki Univ. of Technol., Espoo (Finland). Dept. of Materials Science and Engineering; Korhonen, A.S. [Helsinki Univ. of Technol., Espoo (Finland). Dept. of Materials Science and Engineering; Jiang Laizhu [Dept. of Mechanical Engineering, Helsinki Univ. of Technology, Espoo (Finland); Ristolainen, E. [Centre for Chemical Analysis, Helsinki Univ. of Technology, Espoo (Finland)

1996-11-15

Three commercially available quenched and tempered steels corresponding approximately to AISI 4140 were compared in dry turning using both uncoated and TiN-coated high-speed steel (HSS) inserts. Of three steels A, B and C, steel A did not contain added calcium, while both B and C were calcium-treated. In dry turning with uncoated HSS inserts steel B was best. It gave over 2 times longer wear life than steel A and 1 1/2 times longer than steel C. When the inserts were coated with TiN, the cutting speed could be increased and the order of performance changed dramatically. Steel C was then best, giving nearly 26 times longer wear life than steel A and 9 times longer wear life than steel B. Based on secondary ion mass spectroscopy measurements, the enrichment of alloying elements was studied on the tool surface. The formation of an adherent protective layer on the rake face during turning of steel C is proposed as a mechanism explaining the observed differences in wear lives. (orig.)

Effect of work material composition on the wear life of TiN-coated tools

International Nuclear Information System (INIS)

Harju, E.; Ristolainen, E.

1996-01-01

Three commercially available quenched and tempered steels corresponding approximately to AISI 4140 were compared in dry turning using both uncoated and TiN-coated high-speed steel (HSS) inserts. Of three steels A, B and C, steel A did not contain added calcium, while both B and C were calcium-treated. In dry turning with uncoated HSS inserts steel B was best. It gave over 2 times longer wear life than steel A and 1 1/2 times longer than steel C. When the inserts were coated with TiN, the cutting speed could be increased and the order of performance changed dramatically. Steel C was then best, giving nearly 26 times longer wear life than steel A and 9 times longer wear life than steel B. Based on secondary ion mass spectroscopy measurements, the enrichment of alloying elements was studied on the tool surface. The formation of an adherent protective layer on the rake face during turning of steel C is proposed as a mechanism explaining the observed differences in wear lives. (orig.)

Radiation tagging measures wear at speed

International Nuclear Information System (INIS)

Barrett, Jon.

1994-01-01

A new non-invasive technique for performing accelerated wear and corrosion analysis is particularly relevant to power transmission systems. Wear tests that would normally take days or weeks to complete can now be performed in hours. A tiny patch of the wearing component is made mildly radioactive and the drop in activity as material is worn away is monitored. Known as Thin Layer Activation (TLA), the technology was originally developed and pioneered in-house by the Atomic Energy Authority. Since then, the dominant partner has been the automotive sector where TLA has been used extensively for engine wear and lubrication performance analysis. However, TLA could be used in any wear or corrosion environment. Applications include wear analysis of machine tool cutting surfaces, pump impellers and brake linings to the corrosion monitoring of process plant and pipelines. (author)

Wear performance of laser processed tantalum coatings

Energy Technology Data Exchange (ETDEWEB)

Dittrick, Stanley; Balla, Vamsi Krishna; Bose, Susmita; Bandyopadhyay, Amit, E-mail: amitband@wsu.edu

2011-12-01

This first generation investigation evaluates the in vitro tribological performance of laser-processed Ta coatings on Ti for load-bearing implant applications. Linear reciprocating wear tests in simulated body fluid showed one order of magnitude less wear rate, of the order of 10{sup -4} mm{sup 3}(N.m){sup -1}, for Ta coatings compared to Ti. Our results demonstrate that Ta coatings can potentially minimize the early-stage bone-implant interface micro-motion induced wear debris generation due to their excellent bioactivity comparable to that of hydroxyapatite (HA), high wear resistance and toughness compared to popular HA coatings. Highlights: {yields} In vitro wear performance of laser processed Ta coatings on Ti was evaluated. {yields} Wear tests in SBF showed one order of magnitude less wear for Ta coatings than Ti. {yields} Ta coatings can minimize early-stage micro-motion induced wear debris generation.

The solar ultraviolet B radiation protection provided by shading devices with regard to its diffuse component.

Science.gov (United States)

Kudish, Avraham I; Harari, Marco; Evseev, Efim G

2011-10-01

The composition of the incident solar global ultraviolet B (UVB) radiation with regard to its beam and diffuse radiation fractions is highly relevant with regard to outdoor sun protection. This is especially true with respect to sun protection during leisure-time outdoor sun exposure at the shore and pools, where people tend to escape the sun under shade trees or different types of shading devices, e.g., umbrellas, overhangs, etc., believing they offer protection from the erythemal solar radiation. The degree of sun protection offered by such devices is directly related to the composition of the solar global UVB radiation, i.e., its beam and diffuse fractions. The composition of the incident solar global UVB radiation can be determined by measuring the global UVB (using Solar Light Co. Inc., Model 501A UV-Biometer) and either of its components. The beam component of the UVB radiation was determined by measuring the normal incidence beam radiation using a prototype, tracking instrument consisting of a Solar Light Co. Inc. Model 501A UV-Biometer mounted on an Eppley Solar Tracker Model St-1. The horizontal beam component of the global UVB radiation was calculated from the measured normal incidence using a simple geometric correlation and the diffuse component is determined as the difference between global and horizontal beam radiations. Horizontal and vertical surfaces positioned under a horizontal overhang/sunshade or an umbrella are not fully protected from exposure to solar global UVB radiation. They can receive a significant fraction of the UVB radiation, depending on their location beneath the shading device, the umbrella radius and the albedo (reflectance) of the surrounding ground surface in the case of a vertical surface. Shading devices such as an umbrella or horizontal overhang/shade provide relief from the solar global radiation and do block the solar global UVB radiation to some extent; nevertheless, a significant fraction of the solar global UVB

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.

Backside wear in modern total knee designs.

Science.gov (United States)

Jayabalan, Prakash; Furman, Bridgette D; Cottrell, Jocelyn M; Wright, Timothy M

2007-02-01

Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs with very different locking mechanisms: Insall-Burstein II (IB II), Optetrak, and Advance. A random sample of 71 inserts were obtained from our institution's retrieval collection and examined to assess the extent of wear, depth of wear, and wear damage modes. Patient records were also obtained to determine patient age, body mass index, length of implantation, and reason for revision. Modes of wear damage (abrasion, burnishing, scratching, delamination, third body debris, surface deformation, and pitting) were then scored in each zone from 0 to 3 (0 = 0%, 1 = 0-10%, 2 = 10-50%, and 3 = >50%). The depth of wear was subjectively identified as removal of manufacturing identification markings stamped onto the inferior surface of the polyethylene. Both Advance and IB II polyethylene inserts showed significantly higher scores for backside wear than the Optetrak inserts. All IB II and Advance implants showed evidence of backside wear, whereas 17% (5 out of 30) of the retrieved Optetrak implants had no observable wear. There were no significant differences when comparing the depth of wear score between designs. The locking mechanism greatly affects the propensity for wear and should be considered when choosing a knee implant system.

Estimation of Wear Behavior of Polyphenylene Sulphide Composites Reinforced with Glass/Carbon Fibers, Graphite and Polytetrafluoroethylene, by Pin-on-disc Test

Directory of Open Access Journals (Sweden)

M.A.C. Besnea

2015-03-01

Full Text Available Wear behavior of polyphenylene sulphide composites was investigated according to load and test speed. Two types of materials were studied: first, with 40 wt% glass fiber, and second, with 10 wt% carbon fiber, 10 wt% graphite and 10 wt%. Tribological tests were performed on the universal tribometer UMT-2, using a pin-on-disc device. The friction coefficient and wear rate for the composites were analyzed. As a result of experimental tests, it was established that polymer composite with polyphenylene sulphide matrix, carbon fibers, graphite and polytetrafluorethylene exhibit good wear behavior under operating conditions.

Exploiting heat treatment effects on SMAs macro and microscopic properties in developing fire protection devices

Science.gov (United States)

Burlacu, L.; Cimpoeşu, N.; Bujoreanu, L. G.; Lohan, N. M.

2017-08-01

Ni-Ti shape memory alloys (SMAs) are intelligent alloys which demonstrate unique properties, such as shape memory effect, two-way shape memory effect, super-elasticity and vibration damping which, accompanied by good processability, excellent corrosion resistance and biocompatibility as well as fair wear resistance and cyclic stability, enabled the development of important industrial applications (such as sensors, actuators, fasteners, couplings and valves), medical applications (such as stents, bone implants, orthodontic archwires, minimal invasive surgical equipment) as well as environmental health and safety devices (anti-seismic dampers, fire safety devices). The phase transitions in Ni-Ti SMAs are strongly influenced by processing methods, chemical compositions and thermomechanical history. This paper presents a study of the effects of heat treatment on the mechanical and thermal properties of commercial Ni-Ti shape memory alloy (SMA). The experimental work involved subjecting a SMA rod to heat-treatment consisting in heating up to 500°C, 10 minutes-maintaining and water quenching. Mechanical properties were highlighted by microhardness tests while thermal characteristics were emphasized by differential scanning calorimetry (DSC). The presence of chemical composition fluctuations was checked by X-ray energy dispersive spectroscopy performed with an EDAX Bruker analyzer.

The Effects of Metabolic Work Rate and Ambient Environment on Physiological Tolerance Times While Wearing Explosive and Chemical Personal Protective Equipment

Directory of Open Access Journals (Sweden)

Joseph T. Costello

2015-01-01

Full Text Available This study evaluated the physiological tolerance times when wearing explosive and chemical (>35 kg personal protective equipment (PPE in simulated environmental extremes across a range of differing work intensities. Twelve healthy males undertook nine trials which involved walking on a treadmill at 2.5, 4, and 5.5 km·h−1 in the following environmental conditions, 21, 30, and 37°C wet bulb globe temperature (WBGT. Participants exercised for 60 min or until volitional fatigue, core temperature reached 39°C, or heart rate exceeded 90% of maximum. Tolerance time, core temperature, skin temperature, mean body temperature, heart rate, and body mass loss were measured. Exercise time was reduced in the higher WBGT environments (WBGT37 < WBGT30 < WBGT21; P < 0.05 and work intensities (5.5 < 4 < 2.5 km·h−1; P < 0.001. The majority of trials (85/108; 78.7% were terminated due to participant’s heart rate exceeding 90% of their maximum. A total of eight trials (7.4% lasted the full duration. Only nine (8.3% trials were terminated due to volitional fatigue and six (5.6% due to core temperatures in excess of 39°C. These results demonstrate that physiological tolerance times are influenced by the external environment and workload and that cardiovascular strain is the limiting factor to work tolerance when wearing this heavy multilayered PPE.

30 CFR 57.15003 - Protective footwear.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protective footwear. 57.15003 Section 57.15003... Surface and Underground § 57.15003 Protective footwear. All persons shall wear suitable protective footwear when in or around an area of a mine or plant where a hazard exists which could cause an injury to...

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.

The use of protective gloves by medical personnel

Directory of Open Access Journals (Sweden)

Anna Garus-Pakowska

2013-06-01

Full Text Available Introduction: To minimize the risk of cross-infection between the patient and the medical staff, it is necessary to use individual protective measures such as gloves. According to the recommendations of the Centers for Disease Control and Prevention (CDC and the World Health Organization (WHO, protective gloves should always be used upon contact with blood, mucosa, injured skin or other potentially infectious material. Materials and Methods: The aim of the study was to evaluate, through quasi-observation, the use of protective gloves by medical staff according to the guidelines issued by the CDC and WHO. The results were subject to statistical analysis (p < 0.05. Results: During 1544 hours of observations, 3498 situations were recorded in which wearing protective gloves is demanded from the medical staff. The overall percentage of the observance of using gloves was 50%. The use of gloves depended significantly on the type of ward, profession, performed activity, number of situations that require wearing gloves during the observation unit and the real workload. During the entire study, as many as 718 contacts with patients were observed in which the same gloves were used several times. Conclusion: Wearing disposable protective gloves by the medical staff is insufficient.

Optical wear monitoring

Science.gov (United States)

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.

High frequency circular translation pin-on-disk method for accelerated wear testing of ultrahigh molecular weight polyethylene as a bearing material in total hip arthroplasty.

Science.gov (United States)

Saikko, Vesa

2015-01-21

The temporal change of the direction of sliding relative to the ultrahigh molecular weight polyethylene (UHMWPE) component of prosthetic joints is known to be of crucial importance with respect to wear. One complete revolution of the resultant friction vector is commonly called a wear cycle. It was hypothesized that in order to accelerate the wear test, the cycle frequency may be substantially increased if the circumference of the slide track is reduced in proportion, and still the wear mechanisms remain realistic and no overheating takes place. This requires an additional slow motion mechanism with which the lubrication of the contact is maintained and wear particles are conveyed away from the contact. A three-station, dual motion high frequency circular translation pin-on-disk (HF-CTPOD) device with a relative cycle frequency of 25.3 Hz and an average sliding velocity of 27.4 mm/s was designed. The pins circularly translated at high frequency (1.0 mm per cycle, 24.8 Hz, clockwise), and the disks at low frequency (31.4mm per cycle, 0.5 Hz, counter-clockwise). In a 22 million cycle (10 day) test, the wear rate of conventional gamma-sterilized UHMWPE pins against polished CoCr disks in diluted serum was 1.8 mg per 24 h, which was six times higher than that in the established 1 Hz CTPOD device. The wear mechanisms were similar. Burnishing of the pin was the predominant feature. No overheating took place. With the dual motion HF-CTPOD method, the wear testing of UHMWPE as a bearing material in total hip arthroplasty can be substantially accelerated without concerns of the validity of the wear simulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Surface effects of corrosive media on hardness, friction, and wear of materials

Science.gov (United States)

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

1985-01-01

Hardness, friction, and wear experiments were conducted with magnesium oxide exposed to various corrosive media and also with elemental iron and nickel exposed to water and NaOH. Chlorides such as MgCl2 and sodium containing films were formed on cleaved magnesium oxide surfaces. The MgCl2 films softened the magnesium oxide surfaces and caused high friction and great deformation. Hardness was strongly influenced by the pH value of the HCl-containing solution. The lower the pH, the lower the microhardness. Neither the pH value of nor the immersion time in NaOH containing, NaCl containing, and HNO3 containing solutions influenced the microhardness of magnesium oxide. NaOH formed a protective and low friction film on iron surfaces. The coefficient of friction and the wear for iron were low at concentrations of NaOH higher than 0.01 N. An increase in NaOH concentration resulted in a decrease in the concentration of ferric oxide on the iron surface. It took less NaOH to form a protective, low friction film on nickel than on iron.

Failure Mechanisms of the Protective Coatings for the Hot Stamping Applications

Science.gov (United States)

Zhao, Chen

In the present study, four different nitriding techniques were carried on the ductile irons NAAMS-D6510 and cast steels NAAMS-S0050A, which are widely used stamping die materials; duplex treatments (PVD CrN coating+nitriding) were carried on H13 steels, which are common inserts for the hot stamping dies. Inclined impact-sliding wear tests were performed on the nitriding cases under simulated stamping conditions. Surface profilometer, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to investigate the wear and failure mechanisms of the protective coatings. It was found that the nitrided ductile iron samples performed better than the nitrided cast steel specimens. High temperature inclined impact-sliding wear tests were carried out on the CrN coatings. It was found that the coating performed better at elevated temperature. XPS analysis indicated the top surface layer (about 3-4nm) of the coating was oxidized at 400 °C and formed a Cr2O3 protective film. The in-situ formation of the thin Cr2O3 protective layer likely led to the change of wear mechanisms from severe adhesive failure to mild abrasive wear.

Nonconformance in electromechanical output relays of microprocessor-based protection devices under actual operating conditions

OpenAIRE

Gurevich, Vladimir

2006-01-01

Microprocessor-based protection relays are gradually driving out traditional electromechanical and even electronic protection devices from virtually all fields of power and electrical engineering. In this paper, one of many problems of microprocessor-based relays is discussed: nonconformance of miniature electromechanical output relays under actual operation conditions: switching inductive loads (with tripping CB coils or lockout relay coils) at 220 VDC, and "dry" switching of some control ci...

Flexible protective gloves: The emperor's new clothes

International Nuclear Information System (INIS)

Kelsey, C.A.; Mettler, F.A. Jr.

1990-01-01

The risk of developing skin cancer is estimated for interventional radiologists who do and do not wear thin, flexible protective leaded gloves. The use of these gloves is extremely expensive in terms of dollars per potential cancer prevented. Good radiographic practice without the use of flexible protective gloves provides adequate protection

Device for the burst protection of nuclear reactor pressure vessels

International Nuclear Information System (INIS)

Daublebsky, P.

1976-01-01

The burst protection device has a hood over top and bottom of the pressure vessel with superimposed hinged supports lying in their turn against supporting rings which are connected with each other by vertical bracing. It is proposed to place an intermediate layer between hoods and vertical bracing absorbing thermal stresses, i.e. deforming plastically with gradually increasing pressure, but behaving like a rigid body in the case of shock loads. As a material lead e.g. is proposed. (UWI) [de

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

International Nuclear Information System (INIS)

Zhang Shitang; Zhou Jiansong; Guo Baogang; Zhou Huidi; Pu Yuping; Chen Jianmin

2008-01-01

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si 3 N 4 from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

Energy Technology Data Exchange (ETDEWEB)

Zhang Shitang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Guo Baogang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pu Yuping [Central Iron and Steel Research Institute, Beijing 100081 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: chenjm@lzb.ac.cn

2008-09-15

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si{sub 3}N{sub 4} from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C.

Awareness training and hearing protection devices: Current practices in the South African mining industry

CSIR Research Space (South Africa)

Edwards, A

2012-09-01

Full Text Available This presentation outlines the importance of awareness training of managers at all levels and miners regarding the importance of hearing protection devices and adequate knowledge, motivation and training to prevent hearing loss....

A comparative study of tribological behavior of plasma and D-gun sprayed coatings under different wear modes

International Nuclear Information System (INIS)

Sundararajan, G.; Rao, D.S.; Prasad, K.U.M.; Joshi, S.V.

1998-01-01

In recent years, thermal sprayed protective coatings have gained widespread acceptance for a variety of industrial applications. A vast majority of these applications involve the use of thermal sprayed coatings to combat wear. While plasma spraying is the most versatile variant of all the thermal spray processes, the detonation gun (D-gun) coatings have been a novelty until recently because of their proprietary nature. The present study is aimed at comparing the tribological behavior of coatings deposited using the two above techniques by focusing on some popular coating materials that are widely adopted for wear resistant applications, namely, WC-12% Co, Al 2 O 3 , and Cr 3 C 2 -NiCr. To enable a comprehensive comparison of the above indicated thermal spray techniques as well as coating materials, the deposited coatings were extensively characterized employing microstructural evaluation, microhardness measurements, and XRD analysis for phase constitution. The behavior of these coatings under different wear modes was also evaluated by determining their tribological performance when subjected to solid particle erosion tests, rubber wheel sand abrasion tests, and pin-on-disk sliding wear tests. Among all the coating materials studied, D-gun sprayed WC-12% Co, in general, yields the best performance under different modes of wear, whereas plasma sprayed Al 2 O 3 shows least wear resistance to every wear mode

Cerebral ischemic lesions detected with diffusion-weighted magnetic resonance imaging after carotid artery stenting: Comparison of several anti-embolic protection devices.

Science.gov (United States)

Taha, Mahmoud M; Maeda, Masayuki; Sakaida, Hiroshi; Kawaguchi, Kenji; Toma, Naoki; Yamamoto, Akitaka; Hirose, Tomofumi; Miura, Youichi; Fujimoto, Masashi; Matsushima, Satoshi; Taki, Waro

2009-09-01

Distal embolism is an important periprocedural technical complication with carotid angioplasty and carotid artery stenting (CAS). We evaluated the safety and efficacy of protection devices used during CAS by detecting new cerebral ischemic lesions using diffusion-weighted magnetic resonance imaging in 95 patients who underwent 98 CAS procedures: 34 using single PercuSurge GuardWire, 31 using double balloon protection, 15 using proximal flow reverse protection devices, 14 using Naviballoon, and 4 using filter anti-embolic devices. Diffusion-weighted imaging was performed preoperatively and postoperatively to evaluate the presence of any new embolic cerebral lesions. Postoperative diffusion-weighted imaging revealed 117 new ischemic lesions. Three patients had new ischemic stroke, two minor and one major, all ipsilateral to the treated carotid artery. The remaining patients had clinically silent ischemia. The incidence of new embolic lesions was lower using the proximal flow reverse protection device than with the double balloon protection (33% vs. 48.4%), but the volume of ipsilateral new ischemic lesions per patient was 136.6 mm(3) vs. 86.9 mm(3), respectively. Neuroprotection with Naviballoon yielded ipsilateral lesions of large volume (86.6 mm(3)) and higher number (5.7 lesions per patient) than using the filter anti-embolic device (34.8 mm(3) and 1 lesion per patient). New cerebral ischemic lesions after neuroprotected CAS are usually silent. The lower incidence of distal ischemia using proximal flow reverse and double balloon protection devices is limited by the larger volume and higher number of ischemic lesions.

Cerebral ischemic lesions detected with diffusion-weighted magnetic resonance imaging after carotid artery stenting. Comparison of several anti-embolic protection devices

International Nuclear Information System (INIS)

Taha, M.M.; Maeda, Masayuki; Sakaida, Hiroshi

2009-01-01

Distal embolism is an important periprocedural technical complication with carotid angioplasty and carotid artery stenting (CAS). We evaluated the safety and efficacy of protection devices used during CAS by detecting new cerebral ischemic lesions using diffusion-weighted magnetic resonance imaging in 95 patients who underwent 98 CAS procedures: 34 using single PercuSurge GuardWire, 31 using double balloon protection, 15 using proximal flow reverse protection devices, 14 using Naviballoon, and 4 using filter anti-embolic devices. Diffusion-weighted imaging was performed preoperatively and postoperatively to evaluate the presence of any new embolic cerebral lesions. Postoperative diffusion-weighted imaging revealed 117 new ischemic lesions. Three patients had new ischemic stroke, two minor and one major, all ipsilateral to the treated carotid artery. The remaining patients had clinically silent ischemia. The incidence of new embolic lesions was lower using the proximal flow reverse protection device than with the double balloon protection (33% vs. 48.4%), but the volume of ipsilateral new ischemic lesions per patient was 136.6 mm 3 vs. 86.9 mm 3 , respectively. Neuroprotection with Naviballoon yielded ipsilateral lesions of large volume (86.6 mm 3 ) and higher number (5.7 lesions per patient) than using the filter anti-embolic device (34.8 mm 3 and 1 lesion per patient). New cerebral ischemic lesions after neuroprotected CAS are usually silent. The lower incidence of distal ischemia using proximal flow reverse and double balloon protection devices is limited by the larger volume and higher number of ischemic lesions. (author)

Oscillatory device for use with linear tribometer, for tribological evaluation of biomaterials

Science.gov (United States)

Athayde, J. N.; Siqueira, C. J. M.; Kuromoto, N. K.; Cambraia, H. N.

2017-07-01

Orthopedic implants still have limitations regarding their durability, despite being in use for over fifty years. Particles arising from wear due to the relative motion of their surfaces remain responsible for aseptic failure. This paper presents a device to be coupled with a reciprocal linear tribometer to reproduce the ex vivo wear of biomaterials, allowing the measurement of force and coefficient of friction. The device consists of a structure connected to the tribometer that transforms its reciprocal linear motion into one that is oscillatory for the mechanical assembly that contains the samples to test the desired biomaterials. The tribological pair used for testing consisted of Ultra High Molecular Weight Polyethylene (UHMWPE) in conjunction with the austenitic stainless steel AISI 316L in dry lubrication. The results showed that the values of the coefficient of friction in the linear mode and oscillatory mode and the UHMWPE life curve in the oscillatory mode were consistent with those cited in the literature for tests in a dry lubrication environment. Moreover, the UHMWPE sample life curve showed a reduction in the wear rate that can be explained by the preponderance of a wear mechanism over the others. The volumetric wear showed an increase with the number of cycles.

Microhardness and wear resistance of PEO-coated 5754 aluminum alloy

Science.gov (United States)

Vyaliy, I. E.; Egorkin, V. S.; Sinebryukhov, S. L.; Minaev, A. N.; Gnedenkov, S. V.

2017-09-01

We present results of the study aimed at assessing the effect of duty cycle (D) during plasma electrolytic oxidation (PEO) on protective properties of the coatings produced on 5754 aluminum alloy. It is shown that increasing the duty cycle of a microsecond current pulses leads to increased hardness and reduced abrasive wear of the PEO-layers, improving mechanical properties. The obtained data allowed confirming, that increasing the amount of energy consumed for coating growth leads to the formation of thicker PEO-layers with improved tribological properties. The effect of duty cycle during plasma electrolytic oxidation on protective properties of the produced coatings was assessed.

How patient-selected colors for removable appliances are reflected in electronically tracked compliance (wear times and wear behavior).

Science.gov (United States)

Schott, Timm C; Menne, Dieter

2018-03-27

A broad spectrum of colors for removable appliances, intended to optimize acceptance of treatment and patient cooperation, have been available on the dental market for years. This is the first study to analyze how patient-selected colors are reflected in wear times and wear behavior of removable appliances. The study included 117 children (55 girls and 62 boys) who were treated with active removable plate or functional appliances. All patients were offered to choose from 11 different colors, which were pooled into six groups (black, blue, green, yellow, pink, red) for analysis, or to combine any two to four colors ("multicolored" group) for their appliances. All appliances featured a built-in microsensor (TheraMon; MC Technology, Hargelsberg, Austria) for objective wear-time tracking. Differences between wear times were analyzed using pairwise t tests and Tukey correction. The longest median wear times were recorded in the blue and green groups (≈11 h/d) and the shortest ones in the red and pink groups (≈9 h/d), but they were not significantly influenced by the patient-selected colors. The median wear times involved an age-related decrease by 0.56 h/y that was statistically significant ( P = .00005). No gender-specific patterns of wear behavior were observed. Patient-selected colors for removable appliances can presumably improve acceptance of treatment, but they are not associated with statistically significant improvements in wear time or wear behavior.

The model of the dependence of the abrasive wear value on the maximal linear wear

Directory of Open Access Journals (Sweden)

О.А. Вишневський

2004-01-01

Full Text Available  The relation of the contact area of the rubber roll with a sample and the maximal linear wear value is found. The mathematical model of the dependence of the wear volume weight value on the maximal dimple depth is presented with the friction on abrasive particles fixed nonrigidly. The relation of volume weight wear with the rubber roll contact surface area with a sample with the friction on abrasive particles fixed nonrigidly is established.

Optical-electronic device based on diffraction optical element for control of special protective tags executed from luminophor

Science.gov (United States)

Polyakov, M.; Odinokov, S.

2017-05-01

The report focuses on special printing industry, which is called secure printing, which uses printing techniques to prevent forgery or falsification of security documents. The report considered the possibility of establishing a spectral device for determining the authenticity of certain documents that are protected by machine-readable luminophor labels. The device works in two spectral ranges - visible and near infrared that allows to register Stokes and anti-Stokes spectral components of protective tags. The proposed device allows verification of the authenticity of security documents based on multiple criteria in different spectral ranges. It may be used at enterprises related to the production of security printing products, expert units of law enforcement bodies at check of authenticity of banknotes and other structures.

Quantitive dynamical wear analysis and the convergent quest for significant wear reduction

International Nuclear Information System (INIS)

Sellschop, F.; Kirsch, J.; Derry, T.; Marcus, R.

1984-01-01

The maturing of nuclear physics has made the development of ion beam modification of materials possible, bringing new skills and prospects to the world of materials science. In the following paper an outline is given of the history of ion beam modification of materials (IBMM) and its use for altering the surface of metals to combat wear and friction, and monitoring wear in engines

Study of Tool Wear Mechanisms and Mathematical Modeling of Flank Wear During Machining of Ti Alloy (Ti6Al4V)

Science.gov (United States)

Chetan; Narasimhulu, A.; Ghosh, S.; Rao, P. V.

2015-07-01

Machinability of titanium is poor due to its low thermal conductivity and high chemical affinity. Lower thermal conductivity of titanium alloy is undesirable on the part of cutting tool causing extensive tool wear. The main task of this work is to predict the various wear mechanisms involved during machining of Ti alloy (Ti6Al4V) and to formulate an analytical mathematical tool wear model for the same. It has been found from various experiments that adhesive and diffusion wear are the dominating wear during machining of Ti alloy with PVD coated tungsten carbide tool. It is also clear from the experiments that the tool wear increases with the increase in cutting parameters like speed, feed and depth of cut. The wear model was validated by carrying out dry machining of Ti alloy at suitable cutting conditions. It has been found that the wear model is able to predict the flank wear suitably under gentle cutting conditions.

29 CFR 1926.102 - Eye and face protection.

Science.gov (United States)

2010-07-01

... spectacles, when required by this regulation to wear eye protection, shall be protected by goggles or... 29 Labor 8 2010-07-01 2010-07-01 false Eye and face protection. 1926.102 Section 1926.102 Labor... § 1926.102 Eye and face protection. (a) General. (1) Employees shall be provided with eye and face...

Applicability of out-of-pile fretting wear tests to in-reactor fretting wear-induced failure time prediction

Science.gov (United States)

Kim, Kyu-Tae

2013-02-01

In order to investigate whether or not the grid-to-rod fretting wear-induced fuel failure will occur for newly developed spacer grid spring designs for the fuel lifetime, out-of-pile fretting wear tests with one or two fuel assemblies are to be performed. In this study, the out-of-pile fretting wear tests were performed in order to compare the potential for wear-induced fuel failure in two newly-developed, Korean PWR spacer grid designs. Lasting 20 days, the tests simulated maximum grid-to-rod gap conditions and the worst flow induced vibration effects that might take place over the fuel life time. The fuel rod perforation times calculated from the out-of-pile tests are greater than 1933 days for 2 μm oxidized fuel rods with a 100 μm grid-to-rod gap, whereas those estimated from in-reactor fretting wear failure database may be about in the range of between 60 and 100 days. This large discrepancy in fuel rod perforation may occur due to irradiation-induced cladding oxide microstructure changes on the one hand and a temperature gradient-induced hydrogen content profile across the cladding metal region on the other hand, which may accelerate brittleness in the grid-contacting cladding oxide and metal regions during the reactor operation. A three-phase grid-to-rod fretting wear model is proposed to simulate in-reactor fretting wear progress into the cladding, considering the microstructure changes of the cladding oxide and the hydrogen content profile across the cladding metal region combined with the temperature gradient. The out-of-pile tests cannot be directly applicable to the prediction of in-reactor fretting wear-induced cladding perforations but they can be used only for evaluating a relative wear resistance of one grid design against the other grid design.

Effect of acetabular cup abduction angle on wear of ultrahigh-molecular-weight polyethylene in hip simulator testing.

Science.gov (United States)

Korduba, Laryssa A; Essner, Aaron; Pivec, Robert; Lancin, Perry; Mont, Michael A; Wang, Aiguo; Delanois, Ronald E

2014-10-01

The effect of acetabular component positioning on the wear rates of metal-on-polyethylene articulations has not been extensively studied. Placement of acetabular cups at abduction angles of more than 40° has been noted as a possible reason for early failure caused by increased wear. We conducted a study to evaluate the effects of different acetabular cup abduction angles on polyethylene wear rate, wear area, contact pressure, and contact area. Our in vitro study used a hip joint simulator and finite element analysis to assess the effects of cup orientation at 4 angles (0°, 40°, 50°, 70°) on wear and contact properties. Polyethylene bearings with 28-mm cobalt-chrome femoral heads were cycled in an environment mimicking in vivo joint fluid to determine the volumetric wear rate after 10 million cycles. Contact pressure and contact area for each cup abduction angle were assessed using finite element analysis. Results were correlated with cup abduction angles to determine if there were any differences among the 4 groups. The inverse relationship between volumetric wear rate and acetabular cup inclination angle demonstrated less wear with steeper cup angles. The largest abduction angle (70°) had the lowest contact area, largest contact pressure, and smallest head coverage. Conversely, the smallest abduction angle (0°) had the most wear and most head coverage. Polyethylene wear after total hip arthroplasty is a major cause of osteolysis and aseptic loosening, which may lead to premature implant failure. Several studies have found that high wear rates for cups oriented at steep angles contributed to their failure. Our data demonstrated that larger cup abduction angles were associated with lower, not higher, wear. However, this potentially "protective" effect is likely counteracted by other complications of steep cup angles, including impingement, instability, and edge loading. These factors may be more relevant in explaining why implants fail at a higher rate if

Effects of prior cold work on corrosion and corrosive wear of copper in HNO3 and NaCl solutions

International Nuclear Information System (INIS)

Yin Songbo; Li, D.Y.

2005-01-01

Effects of prior cold work on corrosion and corrosive wear behavior of copper in 0.1 M HNO 3 and 3.5% NaCl solutions, respectively, were investigated using electrochemical tests, electron work function measurements, and sliding corrosive wear tests with and without cathodic protection. Optical microscope and SEM were employed to examine the microstructure and worn surfaces. It was shown that, in general, the prior cold work raised the corrosion rate, but the effect differed in different corrosive media. In both the solutions, pure mechanical wear decreased with an increase in cold work. The prior cold work had a significant influence on the corrosive wear of copper, depending on the corrosive solution and the applied load. In the 0.1 M HNO 3 solution, the ratio of the wear loss caused by corrosion-wear synergism to the total wear loss increased with the cold work and became saturated when the cold work reached a certain level. In the 3.5% NaCl solution, however, this ratio decreased initially and then became relatively stable with respect to the cold work. It was observed that wear of copper in the 3.5% NaCl solution was larger than that in 0.1 M HNO 3 solution, although copper showed lower corrosion rate in the former solution. The experimental observations and the possible mechanisms involved are discussed

Reactor protecting device

International Nuclear Information System (INIS)

Ono, Hiroshi; Kasuga, Hajime; Kasuga, Hiroshi.

1984-01-01

Purpose: To reduce the recycling flowrate thereby decrease the neutron flux level before the reactor shutdown upon generation of abnormality such as increase in the neutron flux, by setting the safety level lower than the value for generating the reaction scram signal. Constitution: A netron flux safety level setter and an instruction signal generator are disposed between a neutron flux detector and a recycling flowrate control device. A neutron flux safety level lower than the level for generating a reactor scram signal and higher that the level for the ordinary operation is set and, if the detection level for the neutron flux in the reactor core arrives at the safety level, a neutron flux decreasing instruction signal is outputted from the instruction signal generator to the recycling flowrate control device to thereby decrease the recycling flowrate and decrease the neutron flux without reaching the reactor shutdown, whereby the thermal safety of the fuel rod can be maintained and the reactor operation performance can be improved. (Moriyama, K.)

Reducing Friction and Wear of Tribological Systems through Hybrid Tribofilm Consisting of Coating and Lubricants

Directory of Open Access Journals (Sweden)

Shuichiro Yazawa

2014-06-01

Full Text Available The role of surface protective additives becomes vital when operating conditions become severe and moving components operate in a boundary lubrication regime. After protecting film is slowly removed by rubbing, it can regenerate through the tribochemical reaction of the additives at the contact. However, there are limitations about the regeneration of the protecting film when additives are totally consumed. On the other hand, there are a lot of hard coatings to protect the steel surface from wear. These can enable the functioning of tribological systems, even in adverse lubrication conditions. However, hard coatings usually make the friction coefficient higher, because of their high interfacial shear strength. Amongst hard coatings, diamond-like carbon (DLC is widely used, because of its relatively low friction and superior wear resistance. In practice, conventional lubricants that are essentially formulated for a steel/steel surface are still used for lubricating machine component surfaces provided with protective coatings, such as DLCs, despite the fact that the surface properties of coatings are quite different from those of steel. It is therefore important that the design of additive molecules and their interaction with coatings should be re-considered. The main aim of this paper is to discuss the DLC and the additive combination that enable tribofilm formation and effective lubrication of tribological systems.

Online Vce measurement method for wear-out monitoring of high power IGBT modules

DEFF Research Database (Denmark)

Beczkowski, Szymon; Ghimire, Pramod; de Vega, Angel Ruiz

2013-01-01

A simple Vce online monitoring circuit is presented in this paper. It allows an accurate wear out prediction of IGBT modules, in high-power applications, during normal converter operation. Bipolar measurement allows monitoring of both IGBT and antiparallel diode. The circuit uses two serial...... offset due to diodes' forward voltage temperature dependency. Using four diodes one can monitor voltages on all power devices in a converter leg....

Tooth Wear Inclination in Great Ape Molars.

Science.gov (United States)

Knight-Sadler, Jordan; Fiorenza, Luca

2017-01-01

Primate dietary diversity is reflected in their dental morphology, with differences in size and shape of teeth. In particular, the tooth wear angle can provide insight into a species' ability to break down certain foods. To examine dietary and masticatory information, digitized polygon models of dental casts provide a basis for quantitative analysis of wear associated with tooth attrition. In this study, we analyze and compare the wear patterns of Pongo pygmaeus, Gorilla gorillagorilla and Pan troglodytes schweinfurthii lower molars, focusing on the degree of inclination of specific wear facets. The variation in wear angles appears to be indicative of jaw movements and the specific stresses imposed on food during mastication, reflecting thus the ecology of these species. Orangutans exhibit flatter wear angles, more typical of a diet consisting of hard and brittle foods, while gorillas show a wear pattern with a high degree of inclination, reflecting thus their more leafy diet. Chimpanzees, on the other hand, show intermediate inclinations, a pattern that could be related to their highly variable diet. This method is demonstrated to be a powerful tool for better understanding the relationship between food, mastication and tooth wear processes in living primates, and can be potentially used to reconstruct the diet of fossil species. © 2017 S. Karger AG, Basel.

Multiscale Modeling of Wear Degradation

KAUST Repository

Moraes, Alvaro; Ruggeri, Fabrizio; Tempone, Raul; Vilanova, Pedro

2014-01-01

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

On the debris-level origins of adhesive wear.

Science.gov (United States)

Aghababaei, Ramin; Warner, Derek H; Molinari, Jean-François

2017-07-25

Every contacting surface inevitably experiences wear. Predicting the exact amount of material loss due to wear relies on empirical data and cannot be obtained from any physical model. Here, we analyze and quantify wear at the most fundamental level, i.e., wear debris particles. Our simulations show that the asperity junction size dictates the debris volume, revealing the origins of the long-standing hypothesized correlation between the wear volume and the real contact area. No correlation, however, is found between the debris volume and the normal applied force at the debris level. Alternatively, we show that the junction size controls the tangential force and sliding distance such that their product, i.e., the tangential work, is always proportional to the debris volume, with a proportionality constant of 1 over the junction shear strength. This study provides an estimation of the debris volume without any empirical factor, resulting in a wear coefficient of unity at the debris level. Discrepant microscopic and macroscopic wear observations and models are then contextualized on the basis of this understanding. This finding offers a way to characterize the wear volume in atomistic simulations and atomic force microscope wear experiments. It also provides a fundamental basis for predicting the wear coefficient for sliding rough contacts, given the statistics of junction clusters sizes.

Usefulness of the protection motivation theory in explaining hearing protection device use among male industrial workers.

Science.gov (United States)

Melamed, S; Rabinowitz, S; Feiner, M; Weisberg, E; Ribak, J

1996-05-01

The present study examined the usefulness of personal variables: noise annoyance, and components of the protection motivation theory (R. W. Rogers, 1983) along with social-organizational factors in explaining hearing protection device (HPD) use among Israeli manufacturing workers. Participants were 281 men exposed to harmful noise levels for which routine HPD use is required by regulation. In practice, 3 HPD user groups were identified: nonusers (n = 38), occasional users (n = 125), and regular users (n = 118). HPD use was objectively verified. HPD use was primarily related to the personal variables but not to management pressure, coworker pressure, or family support. The most powerful predictors of HPD use were perceived self-efficacy (for long-term HPD use), perceived susceptibility (to hearing loss), and noise annoyance, together explaining 48% of the outcome variance. These findings have implications for interventions aimed at motivating workers to use HPDs regularly.

Mechanism of wear and tribofilm formation with ionic liquids and ashless antiwear additives

Science.gov (United States)

Sharma, Vibhu

rubbing surfaces. To address the solubility issue of IL's in BO, ILs with longer alkyl chain structure were carefully selected which helped enhance the van der waals interaction between strongly polar ILs and non-polar base oil. The interaction of IL's with the metal surfaces was examined by analyzing the chemical-mechanical properties of the antiwear films formed. Results indicate that ionic liquids do react with the steel surfaces and form a protective antiwear film composed of iron polyphosphates i.e. short to medium chain length which results in improved wear protection. In addition, soluble boron additive (SB) chemistries were blended with ionic liquids to study the synergism between these two ashless antiwear chemistries. Addition of soluble boron additive (SB) to phosphorous based IL (P_DEHP) reduces the incubation time for antiwear film formation by forming boron oxide/boron phosphate film as early as the rubbing starts and subsequently a more durable iron phosphate film is formed providing long lasting wear protection. The synergistic interaction of boron chemistry with phosphorous based ionic liquids provides superior antiwear properties while eliminating volatile elements such as Zn and S from the additive technology.

Vibrational characteristics and wear of fuel rods

International Nuclear Information System (INIS)

Schmugar, K.L.

1977-01-01

Fuel rod wear, due to vibration, is a continuing concern in the design of liquid-cooled reactors. In my report, the methodology and models that are used to predict fuel rod vibrational response and vibratory wear, in a light water reactor environment, are discussed. This methodology is being followed at present in the design of Westinghouse Nuclear Fuel. Fuel rod vibrations are expressed as the normal bending modes, and sources of rod vibration are examined with special emphasis on flow-induced mechanisms in the stable flow region. In a typical Westinghouse PWR fuel assembly design, each fuel rod is supported at multiple locations along the rod axis by a square-shaped 'grid cell'. For a fuel rod /grid support system, the development of small oscillatory motions, due to fluid flow at the rod/grid interface, results in material wear. A theoretical wear mode is developed using the Archard Theory of Adhesive Wear as the basis. Without question certainty, fretting wear becomes a serious problem if it progresses to the stage where the fuel cladding is penetrated and fuel is exposed to the coolant. Westinghouse fuel is designed to minimize fretting wear by limiting the relative motion between the fuel rod and its supports. The wear producing motion between the fuel rod and its supports occurs when the vibration amplitude exceeds the slippage threshold amplitude

Wear characteristics of current aesthetic dental restorative CAD/CAM materials: two-body wear, gloss retention, roughness and Martens hardness.

Science.gov (United States)

Mörmann, Werner H; Stawarczyk, Bogna; Ender, Andreas; Sener, Beatrice; Attin, Thomas; Mehl, Albert

2013-04-01

This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group. Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million loadings, 49N at 1.7Hz; 3000 thermocycles 5/50°C). Each of the 11 groups consisted of 12 specimens and 12 enamel antagonists. Quantitative analysis of wear was carried out with a 3D-surface analyser. Gloss and roughness measurements were evaluated using a glossmeter and an inductive surface profilometer before and after abrasive toothbrushing of machine-polished specimens. Additionally Martens hardness was measured. Statistically significant differences were calculated with one-way ANOVA (analysis of variance). Statistically significant differences were found for two-body wear, gloss, surface roughness and hardness. Zirconium dioxide ceramics showed no material wear and low wear of the enamel antagonist. Two-body wear of CAD/CAM-silicate and -lithium disilicate ceramics, -hybrid ceramics and -nanocomposite as well as direct nanocomposite did not differ significantly from that of human enamel. Temporary polymers showed significantly higher material wear than permanent materials. Abrasive toothbrushing significantly reduced gloss and increased roughness of all materials except zirconium dioxide ceramics. Gloss retention was highest with zirconium dioxide ceramics, silicate ceramics, hybrid ceramics and nanocomposites. Temporary polymers showed least gloss retention. Martens hardness differed significantly among ceramics, between ceramics and composites, and between resin composites and acrylic block materials as well. All permanent aesthetic CAD/CAM block materials tested behave similarly or better with respect to two-body wear and toothbrushing wear than human enamel, which is not true for temporary polymer CAD

49 CFR 214.117 - Eye and face protection.

Science.gov (United States)

2010-10-01

... corrective lenses, when required by this section to wear eye protection, shall be protected by goggles or... 49 Transportation 4 2010-10-01 2010-10-01 false Eye and face protection. 214.117 Section 214.117..., DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.117 Eye and face...

Wear Characteristics of Metallic Biomaterials: A Review

Science.gov (United States)

Hussein, Mohamed A.; Mohammed, Abdul Samad; Al-Aqeeli, Naser

2015-01-01

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.

The effect of daily fluoride mouth rinsing on enamel erosive/abrasive wear in situ.

Science.gov (United States)

Stenhagen, K R; Hove, L H; Holme, B; Tveit, A B

2013-01-01

It is not known whether application of fluoride agents on enamel results in lasting resistance to erosive/abrasive wear. We investigated if one daily mouth rinse with sodium fluoride (NaF), stannous fluoride (SnF(2)) or titanium tetrafluoride (TiF(4)) solutions protected enamel against erosive/abrasive wear in situ (a paired, randomised and blind study). Sixteen molars were cut into 4 specimens, each with one amalgam filling (measurement reference surface). Two teeth (2 × 4 specimens) were mounted bilaterally (buccal aspects) on acrylic mandibular appliances and worn for 9 days by 8 volunteers. Every morning, the specimens were brushed manually with water (30 s) extra-orally. Then fluoride solutions (0.4% SnF(2) pH 2.5; 0.15% TiF(4) pH 2.1; 0.2% NaF pH 6.5, all 0.05 M F) were applied (2 min). Three of the specimens from each tooth got different treatment, and the fourth served as control. At midday, the specimens were etched for 2 min in 300 ml fresh 0.01 M hydrochloric acid and rinsed in tap water. This etch procedure was repeated in the afternoon. Topographic measurements were performed by a white-light interferometer. Mean surface loss (±SD) for 16 teeth after 9 days was: SnF(2) 1.8 ± 1.9 µm, TiF(4) 3.1 ± 4.8 µm, NaF 26.3 ± 4.7 µm, control 32.3 ± 4.4 µm. Daily rinse with SnF(2), TiF(4) and NaF resulted in 94, 90 and 18% reduction in enamel erosive/abrasive wear, respectively, compared with control (p < 0.05). The superior protective effect of daily rinse with either stannous or titanium tetrafluoride solutions on erosive/abrasive enamel wear is promising. Copyright © 2012 S. Karger AG, Basel.

Measurement of Wear in Radial Journal Bearings

NARCIS (Netherlands)

Ligterink, D.J.; Ligterink, D.J.; de Gee, A.W.J.

1996-01-01

this article, the measurement of wear in radial journal bearings is discussed, where a distinction is made between stationary and non-stationary contact conditions. Starting with Holm/Archard's wear law, equations are derived for the calculation of the specific wear rate k of the bearing material as

Radionuclide measuring systems and improved methods of evaluation for the measurement of wear in stationary and mobile systems

International Nuclear Information System (INIS)

Lausch, W.

1976-01-01

A newly developped flow through measuring unit makes it possible to perform continuous wear measurements on stationary and mobile systems. It was specifically designed for measurements on engine components of passenger cars. For tests of long duration an oil sampling technique was developed. Fully automated measurements are achieved with a sampling device suitable for both stationary and mobile systems. For systems with oil consumption a mathematical model provides for the necessary connection of the loss of wear particles through oil consumption. In certain cases an empirical graphical method can achieve nearly the same results. (orig.) [de

Tyre and road wear prediction

NARCIS (Netherlands)

Lupker, H.A.

2003-01-01

Both tyre wear and road polishing are complex phenomenon, which are obviously strongly related; the energy that polishes the road is the energy that wears the tyre. The both depend non-linearly on numerous parameters, like materials used, vehicle and road usage, environmental conditions (i.e.

Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel

Science.gov (United States)

Çiçek, Adem; Kara, Fuat; Kıvak, Turgay; Ekici, Ergün; Uygur, İlyas

2015-11-01

In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at -145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.

A pilot study of the attitudes of Australian Rules footballers towards protective headgear.

Science.gov (United States)

Finch, C F; McIntosh, A S; McCrory, P; Zazryn, T

2003-12-01

Despite a relatively high risk of injury to participants of Australian Rules football, very few players report wearing protective equipment. The aim of this paper is to describe the results of a pilot survey of the attitudes of community-level Australian Rules football players towards protective headgear and the risk of head injury. Seventy players from four purposefully chosen clubs in metropolitan Melbourne completed a self-report questionnaire at the end of the 2000-playing season. Almost all players (91.4%) reported they did not wear protective headgear during the 2000 season. Non-headgear users said that headgear was too uncomfortable (47.4%) and they didn't like it (42.1%). However, 80.0% of non-users said they would wear it if it prevented injury. The major motivation for wearing headgear was to prevent injury. Players considered rugby, boxing and driving a car, to be associated with a higher-risk of head injury than Australian Rules football. As a group, the players perceived the risk of head injury in Australian Rules football to be low to moderate when compared to other sports and activities. This partially explains why so few players wore protective headgear. Repeat surveys on a larger sample should be conducted to further understand the attitudes towards protective headgear and perceptions of risk in community-level Australian football players.

Web software for the control and management of radiation protection devices in the Cadarache site

International Nuclear Information System (INIS)

Beltritti, F.

2010-01-01

This series of slides presents how to use a new software dedicated to the management of the periodical controls that have to be performed on the equipment involved in radiation protection. This software is ready to be dispatched on the CEA site of Cadarache. This software gives information on: the device to be controlled, the controls that have to be performed, the procedures to follow to make the test, the equipment necessary for the test particularly the need for radioactive sources, the maintenance of the device, the previous measurements and in the end the device's conformity. An evaluation of the conformity of all the devices present in a building or an area or of a particular type can be easily obtained. (A.C.)

“Can I wear this?” : blending clothing and digital expression by wearing dynamic fabric

NARCIS (Netherlands)

Mackey, A.M.; Wakkary, R.L.; Wensveen, S.A.G.; Tomico Plasencia, O

2017-01-01

We explore the future scenario of wearing garments with digital display capabilities, or dynamic fabric, in everyday life. Our study, called Greenscreen Dress, investigates the experience of wearing dynamic fabric and how this type of garment quality might alter our daily interactions with clothing

Gaussian process regression for tool wear prediction

Science.gov (United States)

Kong, Dongdong; Chen, Yongjie; Li, Ning

2018-05-01

To realize and accelerate the pace of intelligent manufacturing, this paper presents a novel tool wear assessment technique based on the integrated radial basis function based kernel principal component analysis (KPCA_IRBF) and Gaussian process regression (GPR) for real-timely and accurately monitoring the in-process tool wear parameters (flank wear width). The KPCA_IRBF is a kind of new nonlinear dimension-increment technique and firstly proposed for feature fusion. The tool wear predictive value and the corresponding confidence interval are both provided by utilizing the GPR model. Besides, GPR performs better than artificial neural networks (ANN) and support vector machines (SVM) in prediction accuracy since the Gaussian noises can be modeled quantitatively in the GPR model. However, the existence of noises will affect the stability of the confidence interval seriously. In this work, the proposed KPCA_IRBF technique helps to remove the noises and weaken its negative effects so as to make the confidence interval compressed greatly and more smoothed, which is conducive for monitoring the tool wear accurately. Moreover, the selection of kernel parameter in KPCA_IRBF can be easily carried out in a much larger selectable region in comparison with the conventional KPCA_RBF technique, which helps to improve the efficiency of model construction. Ten sets of cutting tests are conducted to validate the effectiveness of the presented tool wear assessment technique. The experimental results show that the in-process flank wear width of tool inserts can be monitored accurately by utilizing the presented tool wear assessment technique which is robust under a variety of cutting conditions. This study lays the foundation for tool wear monitoring in real industrial settings.

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.

Aging assessment of surge protective devices in nuclear power plants

International Nuclear Information System (INIS)

Davis, J.F.; Subudhi, M.; Carroll, D.P.

1996-01-01

An assessment was performed to determine the effects of aging on the performance and availability of surge protective devices (SPDs), used in electrical power and control systems in nuclear power plants. Although SPDs have not been classified as safety-related, they are risk-important because they can minimize the initiating event frequencies associated with loss of offsite power and reactor trips. Conversely, their failure due to age might cause some of those initiating events, e.g., through short circuit failure modes, or by allowing deterioration of the safety-related component(s) they are protecting from overvoltages, perhaps preventing a reactor trip, from an open circuit failure mode. From the data evaluated during 1980--1994, it was found that failures of surge arresters and suppressers by short circuits were neither a significant risk nor safety concern, and there were no failures of surge suppressers preventing a reactor trip. Simulations, using the ElectroMagnetic Transients Program (EMTP) were performed to determine the adequacy of high voltage surge arresters

Self-dispersed crumpled graphene balls in oil for friction and wear reduction.

Science.gov (United States)

Dou, Xuan; Koltonow, Andrew R; He, Xingliang; Jang, Hee Dong; Wang, Qian; Chung, Yip-Wah; Huang, Jiaxing

2016-02-09

Ultrafine particles are often used as lubricant additives because they are capable of entering tribological contacts to reduce friction and protect surfaces from wear. They tend to be more stable than molecular additives under high thermal and mechanical stresses during rubbing. It is highly desirable for these particles to remain well dispersed in oil without relying on molecular ligands. Borrowing from the analogy that pieces of paper that are crumpled do not readily stick to each other (unlike flat sheets), we expect that ultrafine particles resembling miniaturized crumpled paper balls should self-disperse in oil and could act like nanoscale ball bearings to reduce friction and wear. Here we report the use of crumpled graphene balls as a high-performance additive that can significantly improve the lubrication properties of polyalphaolefin base oil. The tribological performance of crumpled graphene balls is only weakly dependent on their concentration in oil and readily exceeds that of other carbon additives such as graphite, reduced graphene oxide, and carbon black. Notably, polyalphaolefin base oil with only 0.01-0.1 wt % of crumpled graphene balls outperforms a fully formulated commercial lubricant in terms of friction and wear reduction.

A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

International Nuclear Information System (INIS)

Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok

2012-01-01

Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

New challenge for the radiation protection: devices for the radioactivity dispersion

International Nuclear Information System (INIS)

Mora, J. C.; Robles, B.; Cancio, C.

2006-01-01

In recent years the terrorist attacks produced in several countries have changed the mind of the security experts. This has also included the Radiation Protection aspects. Newly considered features have required the update of emergency response and preparedness, ad well as a greater emphasis on security. Within the Radiation Protection field has been introduced the radiological and nuclear terrorism definition. almost every organism and research centre involved in Radiation Protection is nowadays working on. The possible terrorist attack scenarios have already been defined and the use of an explosive to disperse radioactive material, known as a Radiation Dispersion Devices (RDD), has been specified as the most probable one. Studies to mitigate against the chance of attack and to mitigate the consequences of any attack with a RDD are complex, due to the innovation that introduce. This leads to a need to take some immediate preventative actions and to carry out additional R and D efforts. This document presents some considerations on the possible RDD design and behaviour in order to prevent and prepare against a possible attack. (Author) 17 refs

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 ...

Sun protective behaviour and sunburn prevalence in primary and secondary schoolchildren in western Switzerland.

Science.gov (United States)

Ackermann, Simone; Vuadens, Anne; Levi, Fabio; Bulliard, Jean-Luc

2016-01-01

Although solar overexposure during childhood and adolescence increases the risk of melanoma, determinants of sunburn and sun protective behaviours of Swiss children have scarcely been explored. We investigated sunburn occurrence and sun protective behaviours of schoolchildren in western Switzerland, the region with the highest incidence of melanoma in Europe. Self-reported questionnaires were administered during regular classes to pupils in 5th (primary school, n = 431), 8th and 11th grades (secondary school, n = 837) in the 18 public schools of La Chaux-de-Fonds. Descriptive statistics and multivariate logistic regression analyses were performed to assess predictors of sunburns and of three sun protective behaviours (sunscreen, shade, wear of covering clothes). Response rate was 91%. Sunburn prevalence over the preceding year was high (60% at least one sunburn, 30% at least two, 43% at least one severe sunburn). Younger age, fair skin, regular sunscreen use, higher sun-related knowledge and preference for a tanned skin were predictors of sunburn. Sunscreen was the most used protective measure (69%), followed by seeking shade (33%) and wearing long-sleeved shirts (32%). Decline in all protective measures was observed in older pupils and those with pro-tan attitudes. The wear of covering clothes was significantly associated with sunscreen use and seeking shade. Parental encouragement favoured sunscreen use and wearing of protective clothes. Sunscreen use as a last protective barrier against ultraviolet radiation should be better emphasised in prevention campaigns targeting children and adolescents. Multi-faceted interventions, including role models, parents and peers should help to improve children's sun protective behaviours.

Effect of Load on Friction-Wear Behavior of HVOF-Sprayed WC-12Co Coatings

Science.gov (United States)

Yifu, Jin; Weicheng, Kong; Tianyuan, Sheng; Ruihong, Zhang; Dejun, Kong

2017-07-01

A WC-12Co coating was sprayed on AISI H13 hot work mold steel using a high-velocity oxygen fuel. The morphologies, phase compositions, and distributions of chemical elements of the obtained coatings were analyzed using a field emission scanning electron microscope, x-ray diffraction, and energy-dispersive spectroscope (EDS), respectively. The friction-wear behaviors under different loads were investigated using a reciprocating wear tester; the morphologies and distributions of the chemical elements of worn tracks were analyzed using a SEM and its configured EDS, respectively. The results show the reunited grains of WC are held together by the Co binder; the primary phases of the coating are WC, Co, and a small amount of W2C and W, owing to the oxidation and decarburization of WC. Inter-diffusion of Fe and W between the coating and the substrate is shown, which indicates a good coating adhesion. The values of the average coefficient of friction under the loads of 40, 80, and 120 N are 0.29, 0.31, and 0.49, respectively. The WC grains are pulled out of the coating during the sliding wear test, but the coating maintains its integrity, suggesting that the coating is intact and continuously protects the substrate from wearing.

78 FR 25308 - Proposed Collection; Comment Request; Coal Mine Dust Sampling Devices

Science.gov (United States)

2013-04-30

...; Coal Mine Dust Sampling Devices AGENCY: Mine Safety and Health Administration, Labor. ACTION: 60-Day... mines. CPDMs must be designed and constructed for coal miners to wear and operate without impeding their... related to Coal Mine Dust Sampling Devices. MSHA is particularly interested in comments that: Evaluate...

Balance between Privacy Protecting and Selling User Data of Wearable Devices

OpenAIRE

Huang, Kuang-Chiu; Hsu, Jung-Fang

2017-01-01

Smart bracelets are capable of identifying individual data, which can synchronize the step count, mileage, calorie consumption, heart rate, sleeping data and even the pictures users uploaded with the APP. This feature is so convenient on one hand but makes us lose control of our privacy on the other hand. With poor privacy protection mechanism embedded in these wearable devices that hackers can easily invade and steal user data. In addition, most smart bracelet companies have not made a clear...

Effect of heat input on microstructure, wear and friction behavior of (wt.-%) 50FeCrC-20FeW-30FeB coating on AISI 1020 produced by using PTA welding.

Science.gov (United States)

Özel, Cihan; Gürgenç, Turan

2018-01-01

In this study, AISI 1020 steel surface was coated in different heat inputs with (wt.-%) 50FeCrC-20FeW-30FeB powder mixture by using plasma transferred arc (PTA) welding method. The microstructure of the coated samples were investigated by using optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDS). The hardness was measured with micro hardness test device. The dry sliding wear and friction coefficient properties were determined using a block-on-disk type wear test device. Wear tests were performed at 19.62 N, 39.24 N, 58.86 N load and the sliding distance of 900 m. The results were shown that different microstructures formed due to the heat input change. The highest average micro hardness value was measured at 1217 HV on sample coated with low heat input. It was determined that the wear resistance decreased with increasing heat input.

Distal protection filter device efficacy with carotid artery stenting: comparison between a distal protection filter and a distal protection balloon.

Science.gov (United States)

Iko, Minoru; Tsutsumi, Masanori; Aikawa, Hiroshi; Matsumoto, Yoshihisa; Go, Yoshinori; Nii, Kouhei; Abe, Gorou; Ye, Iwae; Nomoto, Yasuyuki; Kazekawa, Kiyoshi

2013-01-01

This retrospective study aimed to compare the effectiveness of the embolization prevention mechanism of two types of embolic protection device (EPD)-a distal protection balloon (DPB) and a distal protection filter (DPF). Subjects were 164 patients scheduled to undergo carotid artery stenting: a DPB was used in 82 cases (DPB group) from April 2007 until June 2010, and a DPF was used in 82 cases (DPF group) from July 2010 to July 2011. Rates of positive findings on postoperative diffusion-weighted imaging (DWI) and stroke incidence were compared. Positive postoperative DWI results were found in 34 cases in the DPB group (41.4 %), but in only 22 cases in the DPF group (26.8 %), and there was only a small significant difference within the DPF group. In the DPB group, there was one case of transient ischemic attack (TIA) (1.2 %) and four cases of brain infarction (2 minor strokes, 2 major strokes; 4.9 %), compared to the DFP group with one case of TIA (1.2 %) and no cases of minor or major strokes. In this study, significantly lower rates of occurrence of DWI ischemic lesions and intraoperative embolization were associated with use of the DPF compared to the DPB.

Effects of Hearing Protection Device Attenuation on Unmanned Aerial Vehicle (UAV) Audio Signatures

Science.gov (United States)

2016-03-01

UAV ) Audio Signatures by Melissa Bezandry, Adrienne Raglin, and John Noble Approved for public release; distribution...Research Laboratory Effects of Hearing Protection Device Attenuation on Unmanned Aerial Vehicle ( UAV ) Audio Signatures by Melissa Bezandry...Aerial Vehicle ( UAV ) Audio Signatures 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Melissa Bezandry

Safety and effectiveness of the INVATEC MO.MA proximal cerebral protection device during carotid artery stenting: results from the ARMOUR pivotal trial.

Science.gov (United States)

Ansel, Gary M; Hopkins, L Nelson; Jaff, Michael R; Rubino, Paolo; Bacharach, J Michael; Scheinert, Dierk; Myla, Subbarao; Das, Tony; Cremonesi, Alberto

2010-07-01

The multicenter ARMOUR (ProximAl PRotection with the MO.MA Device DUring CaRotid Stenting) trial evaluated the 30-day safety and effectiveness of the MO.MA Proximal Cerebral Protection Device (Invatec, Roncadelle, Italy) utilized to treat high surgical risk patients undergoing carotid artery stenting (CAS). Distal embolic protection devices (EPD) have been traditionally utilized during CAS. The MO.MA device acts as a balloon occlusion "endovascular clamping" system to achieve cerebral protection prior to crossing the carotid stenosis. This prospective registry enrolled 262 subjects, 37 roll-in and 225 pivotal subjects evaluated with intention to treat (ITT) from September 2007 to February 2009. Subjects underwent CAS using the MO.MA device. The primary endpoint, myocardial infarction, stroke, or death through 30 days (30-day major adverse cardiac and cerebrovascular events [MACCE]) was compared to a performance goal of 13% derived from trials utilizing distal EPD. For the ITT population, the mean age was 74.7 years with 66.7% of the cohort being male. Symptomatic patients comprised 15.1% and 28.9% were octogenarians. Device success was 98.2% and procedural success was 93.2%. The 30-day MACCE rate was 2.7% [95% CI (1.0-5.8%)] with a 30-day major stroke rate of 0.9%. No symptomatic patient suffered a stroke during this trial. The ARMOUR trial demonstrated that the MO.MA(R) Proximal Cerebral Protection Device is safe and effective for high surgical risk patients undergoing CAS. The absence of stroke in symptomatic patients is the lowest rate reported in any independently adjudicated prospective multicenter registry trial to date. (c) 2010 Wiley-Liss, Inc.

Inventions in the nanotechnological area considerably increase wear- and chemical resistance of construction products

Directory of Open Access Journals (Sweden)

VLASOV Vladimir Alexeevich

2014-08-01

Full Text Available The invention «Reinforced flaked element made of natural or conglomerate stone and its multilayer protective coating (RU 2520193» is referred to construction materials. Reinforced flaked element made of natural or conglomerate stone consists of: natural or conglomerate materials as the basis; multilayer coating which protects the mentioned basis from chemical substances and wearing mechanical factors influencing on this element where the multilayer coating includes at least three layers formed by one or many film-forming compositions which comprise top layer with scratch-resistant nanoparticles and encircled with polyester, melamine, phenolic, acryl or epoxy resin (or any combination of them which provides protection against scratches; damper intermediate layer made of epoxy and/or acryl resin which provides impact resistant; lower layer adjoining to the basis and containing particles of Al2O3 or silicon carbide plus acryl polymer and providing resistance to abrasive wear. Technical result is increased wear- and chemical resistance of flaked elements from natural or conglomerate materials. The invention «Fine organic suspension of carbon metal-containing nanostructures and the method to produce it (RU 2515858» is referred to the area of physical and colloid chemistry and can be used to obtain polymer compositions. Fine organic suspension of carbon metal-containing nanostructures is produced by interaction between nanostructures and polyethylenepolyamine. At first the powder of carbon metalcontaining nanostructures (which are nanoparticles of 3d-metal such as copper, cobalt, nickel stabilized in carbon nanostructures is mechanically milled, then it is mechanically ground with polyethylenepolyamine introduced portionally unless and until the content of nanostructures is less 1 g/ml. The invention results in decreased power inputs as the obtained fine organic suspension of carbon and metal-containing nanostructures is able to recover due to

Absorbed doses by a technician, with and without (simulating) use of protection devices, in bone scintigraphy examination

International Nuclear Information System (INIS)

Jesus Lopes Filho, F. de; Antonio Filho, J.; Colaco, W.; Silveira, S.V. da

1992-01-01

The relation between the whole-body dose and the dose localized in body pants of a technician work in nuclear medicine was investigated by dosimetric films and thermoluminescent dosemeters. The investigation was made with and without a suitable protection devices. The results were discussed by a radiological protection view. (C.G.C.)

3D finite element modeling of sliding wear

Science.gov (United States)

Buentello Hernandez, Rodolfo G.

Wear is defined as "the removal of material volume through some mechanical process between two surfaces". There are many mechanical situations that can induce wear and each can involve many wear mechanisms. This research focuses on the mechanical wear due to dry sliding between two surfaces. Currently there is a need to identify and compare materials that would endure sliding wear under severe conditions such as high velocities. The high costs associated with the field experimentation of systems subject to high-speed sliding, has prevented the collection of the necessary data required to fully characterize this phenomena. Simulating wear through Finite Elements (FE) would enable its prediction under different scenarios and would reduce experimentation costs. In the aerospace, automotive and weapon industries such a model can aid in material selection, design and/or testing of systems subjected to wear in bearings, gears, brakes, gun barrels, slippers, locomotive wheels, or even rocket test tracks. The 3D wear model presented in this dissertation allows one to reasonably predict high-speed sliding mechanical wear between two materials. The model predictions are reasonable, when compared against those measured on a sled slipper traveling over the Holloman High Speed Tests Track. This slipper traveled a distance of 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s.

Fish-protection devices at unscreened water diversions can reduce entrainment: evidence from behavioural laboratory investigations

Science.gov (United States)

Poletto, Jamilynn B.; Cocherell, Dennis E.; Mussen, Timothy D.; Ercan, Ali; Bandeh, Hossein; Kavvas, M. Levent; Cech, Joseph J.; Fangue, Nann A.

2015-01-01

Diversion (i.e. extraction) of water from rivers and estuaries can potentially affect native wildlife populations if operation is not carefully managed. For example, open, unmodified water diversions can act as a source of injury or mortality to resident or migratory fishes from entrainment and impingement, and can cause habitat degradation and fragmentation. Fish-protection devices, such as exclusion screens, louvres or sensory deterrents, can physically or behaviourally deter fish from approaching or being entrained into water diversions. However, empirical assessment of their efficacy is often lacking or is investigated only for particular economically or culturally important fishes, such as salmonids. The Southern population of anadromous green sturgeon (Acipenser medirostris) is listed as threatened in California, and there is a high density of water diversions located within their native range (the Sacramento–San Joaquin watershed). Coupled with their unique physiology and behaviour compared with many other fishes native to California, the green sturgeon is susceptible to entrainment into diversions and is an ideal species with which to study the efficacy of mitigation techniques. Therefore, we investigated juvenile green sturgeon (188–202 days post-hatch) in the presence of several fish-protection devices to assess behaviour and entrainment risk. Using a large experimental flume (∼500 kl), we found that compared with an open diversion pipe (control), the addition of a trash-rack box, louvre box, or perforated cylinder on the pipe inlet all significantly reduced the proportion of fish that were entrained through the pipe (P = 0.03, P = 0.028, and P = 0.028, respectively). Likewise, these devices decreased entrainment risk during a single movement past the pipe by between 60 and 96%. These fish-protection devices should decrease the risk of fish entrainment during water-diversion activities. PMID:27293725

Wear of human enamel: a quantitative in vitro assessment.

Science.gov (United States)

Kaidonis, J A; Richards, L C; Townsend, G C; Tansley, G D

1998-12-01

Many factors influence the extent and rate at which enamel wears. Clinical studies in humans are limited by difficulties in the accurate quantification of intra-oral wear and by a lack of control over the oral environment. The purpose of this study was to determine the wear characteristics of human dental enamel under controlled experimental conditions. An electro-mechanical tooth wear machine, in which opposing enamel surfaces of sectioned, extracted teeth were worn under various conditions, was used to simulate tooth grinding or bruxism. Enamel surface wear was quantified by weight to an accuracy of 0.1 mg, with water uptake and loss controlled. The variables considered included the structure and hardness of enamel, facet area, duration of tooth contact, relative speed of opposing surfaces, temperature, load, pH, and the nature of the lubricant. Enamel wear under non-lubricated conditions increased with increasing load over the range of 1.7 to 16.2 kg. The addition of a liquid lubricant (pH = 7) reduced enamel wear up to 6.7 kg, but when the load increased above this threshold, the rate of wear increased dramatically. With the viscosity of the lubricant constant and pH = 3, the rate of wear was further reduced to less than 10% of the non-lubricated rate at 9.95 kg, after which the rate again increased substantially. Under more extreme conditions (pH = 1.2, simulating gastric acids), the wear was excessive under all experimental loads. When saliva was used as a lubricant, the amount of wear was relatively low at 9.95 kg, but rapid wear occurred at 14.2 kg and above. These results indicate that under non-lubricated conditions, enamel wear remains low at high loads due to the dry-lubricating capabilities of fine enamel powder. Under lubricated conditions, low loads with an acidic lubricant lead to little enamel wear, whereas very low pH results in a high rate of wear under all loads.

Protection during production: Problems due to prevention? Nail and skin condition after prolonged wearing of occlusive gloves.

Science.gov (United States)

Weistenhöfer, Wobbeke; Uter, Wolfgang; Drexler, Hans

2017-01-01

Wearing of occlusive gloves during the whole working shift is considered a risk factor for developing hand eczema, similar to wet work. Moreover, the increased hydration due to glove occlusion may lead to brittle nails. Two hundred and seventy clean room workers, wearing occlusive gloves for prolonged periods, and 135 administrative employees not using gloves were investigated. This included a dermatological examination of the nails and the hands, using the Hand Eczema ScoRe for Occupational Screening (HEROS), measurement of transepidermal water loss (TEWL), and a standardized interview. Of the clean room workers, 39%, mainly women, reported nail problems, mostly brittle nails with onychoschisis. Skin score values showed no significant differences between HEROS values of both groups. TEWL values of exposed subjects were similar to TEWL values of controls 40 min after taking off the occlusive gloves. In a multiple linear regression analysis, male gender and duration of employment in the clean room were associated with a significant increase in TEWL values. The effect of occlusion on TEWL seems to be predominantly transient and not be indicative of a damaged skin barrier. This study confirmed the results of a previous investigation showing no serious adverse effect of wearing of occlusive gloves on skin condition without exposure to additional hazardous substances. However, occlusion leads to softened nails prone to mechanical injury. Therefore, specific prevention instructions are required to pay attention to this side effect of occlusion.

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.

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

Science.gov (United States)

2010-01-01

Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. Results The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. Conclusions The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in knee joint replacement

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

Directory of Open Access Journals (Sweden)

Denkena Berend

2010-06-01

Full Text Available Abstract Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. Results The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. Conclusions The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty.

Science.gov (United States)

Richter, Berna I; Ostermeier, Sven; Turger, Anke; Denkena, Berend; Hurschler, Christof

2010-06-15

Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in knee joint replacement implants.

Tribological Effects of Mineral-Oil Lubricant Contamination with Biofuels: A Pin-on-Disk Tribometry and Wear Study

Directory of Open Access Journals (Sweden)

S. M. Shanta

2011-01-01

Full Text Available Use of biodiesel produces engine oil dilution because of unburned biodiesel impinging on cold walls of the combustion chamber, being scrapped to the oil pan, and leading to changes of oil friction, wear and lubricity properties. In this paper, mixtures of SAE 15W-40 oil, which were contaminated by known percentages of the biodiesels from canola oil, peanut oil, soybean oil, and chicken fat, were tested in a pin-on-disk tribometer. A contact was employed of AISI 1018 steel disk and AISI 316 stainless-steel ball for pin material, and friction force and specific wear were measured. Wear on the disk surfaces showed that any degree of mineral-oil dilution by the tested biodiesels reduces the wear protection of engine oil even at small mixture percentages. However, these reductions were not substantially different than those observed for same percentages of dilution of mineral oil by fossil diesel. The tested mixture of oil contaminated with animal fat feedstock (e.g., chicken fat biodiesel showed the best wear behavior as compared to those for the other tested mixtures (of mineral oil with vegetable feedstock biodiesel dilutions. Obtained results are discussed as baseline for further studies in a renewable energy multidisciplinary approach on biofuels and biolubes.

A simple device to protect against osteoradionecrosis induced by interstitial irradiation

International Nuclear Information System (INIS)

Levendag, P.C.; Visch, L.L.; Driver, N.

1990-01-01

The incidence of osteoradionecrosis has declined since the introduction of preventive oral hygiene programs and meticulous dental evaluations before and after irradiation. Nevertheless, radiation dose per se still remains an important factor in osteoradionecrosis. Interstitial radiation has received much attention in the past decade since the use of flexible afterloading systems. It has become common practice in large oncology centers to implant radiation carriers in bulky tumor in the oral cavity and/or oropharynx. For interstitial radiation, with or without external radiation, minimal tumor doses are often cited to be more than 70 Gy. Unfortunately, if the mandible receives more than 70 Gy, it is at risk for the development of osteoradionecrosis. Therefore a simple protective lead device has been designed for routine use in brachytherapy in oral cavity tumors to reduce the dose to the mandible. This device will diminish the potential risk of osteoradionecrosis development

Skin Cancer-Sun Knowledge and Sun Protection Behaviors of Liver Transplant Recipients in Turkey.

Science.gov (United States)

Haney, Meryem Ozturk; Ordin, Yaprak Sarigol; Arkan, Gulcihan

2017-09-08

The aim of this study was to compare liver transplant recipients (LTRs) with the general population regarding their knowledge of skin cancer, sun health, sun protection behaviors, and affecting factors. This cross-sectional study was conducted in Turkey between March 2016 and September 2016 with 104 LTRs and 100 participants from the general population group (GPG). The mean age of the LTRs was 53.2 ± 11.8 and that of the GPG was 42.7 ± 14.5. The LTRs' skin cancer and sun knowledge were significantly lower than in the GPG, but there was no difference between the two groups in terms of their sun protection behavior scores. The most commonly used sun protection behaviors of LTRs were not being outside and not sunbathing between 10 a.m. and 4 p.m., wearing clothing that covers the skin, and avoiding the solarium. Behaviors commonly practiced by the GPG were wearing sunglasses, wearing sunscreen with a sun protection factor of 15 or higher before going outside, wearing sunscreen at the beach, while swimming or doing physical activity outside, and reapplying it every 2 h. Results of our study will contribute to the development of education and training programs for LTRs on skin cancer. The results also demonstrated the importance of practicing adequate sun protection behaviors which will certainly impact their future health.

Fabrication of wear-resistant silicon microprobe tips for high-speed surface roughness scanning devices

Science.gov (United States)

Wasisto, Hutomo Suryo; Yu, Feng; Doering, Lutz; Völlmeke, Stefan; Brand, Uwe; Bakin, Andrey; Waag, Andreas; Peiner, Erwin

2015-05-01

Silicon microprobe tips are fabricated and integrated with piezoresistive cantilever sensors for high-speed surface roughness scanning systems. The fabrication steps of the high-aspect-ratio silicon microprobe tips were started with photolithography and wet etching of potassium hydroxide (KOH) resulting in crystal-dependent micropyramids. Subsequently, thin conformal wear-resistant layer coating of aluminum oxide (Al2O3) was demonstrated on the backside of the piezoresistive cantilever free end using atomic layer deposition (ALD) method in a binary reaction sequence with a low thermal process and precursors of trimethyl aluminum and water. The deposited Al2O3 layer had a thickness of 14 nm. The captured atomic force microscopy (AFM) image exhibits a root mean square deviation of 0.65 nm confirming the deposited Al2O3 surface quality. Furthermore, vacuum-evaporated 30-nm/200-nm-thick Au/Cr layers were patterned by lift-off and served as an etch mask for Al2O3 wet etching and in ICP cryogenic dry etching. By using SF6/O2 plasma during inductively coupled plasma (ICP) cryogenic dry etching, micropillar tips were obtained. From the preliminary friction and wear data, the developed silicon cantilever sensor has been successfully used in 100 fast measurements of 5- mm-long standard artifact surface with a speed of 15 mm/s and forces of 60-100 μN. Moreover, the results yielded by the fabricated silicon cantilever sensor are in very good agreement with those of calibrated profilometer. These tactile sensors are targeted for use in high-aspect-ratio microform metrology.

Identification, investigation and analysis of end-of-wind protection devices for vertical and incline shafts.

CSIR Research Space (South Africa)

Ottermann, RW

2000-12-01

Full Text Available The occurrence and cause of overwind and underwind events in underground mining were investigated in conjunction with devices, which are at present being applied to prevent and control such incidents. Proposals for in-shaft systems to protect...

Comparison of high temperature wear behaviour of plasma sprayed WC–Co coated and hard chromium plated AISI 304 austenitic stainless steel

International Nuclear Information System (INIS)

Balamurugan, G.M.; Duraiselvam, Muthukannan; Anandakrishnan, V.

2012-01-01

Highlights: ► WC–12wt.%Co powders were deposited to a thickness of 300 μm on to steel substrates. ► The micro hardness of the above coatings was lower than that of chromium plating. ► Wear resistance of chromium coating was increased up to five times of AISI 304 austenitic stainless steel. ► Wear resistance of chromium coat higher than plasma coat at different temperatures. -- Abstract: The wear behaviour of plasma sprayed coating and hard chrome plating on AISI 304 austenitic stainless steel substrate is experimentally investigated in unlubricated conditions. Experiments were conducted at different temperatures (room temp, 100 °C, 200 °C and 300 °C) with 50 N load and 1 m/s sliding velocity. Wear tests were carried out by dry sliding contact of EN-24 medium carbon steel pin as counterpart on a pin-on-disc wear testing machine. In both coatings, specimens were characterised by hardness, microstructure, coating density and sliding wear resistance. Wear studies showed that the hard chromium coating exhibited improved tribological performance than that of the plasma sprayed WC–Co coating. X-ray diffraction analysis (XRD) of the coatings showed that the better wear resistance at high temperature has been attributed to the formation of a protective oxide layer at the surface during sliding. The wear mechanisms were investigated through scanning electron microscopy (SEM) and XRD. It was observed that the chromium coating provided higher hardness, good adhesion with the substrate and nearly five times the wear resistance than that obtained by uncoated AISI 304 austenitic stainless steel.

Study of protective coatings for aluminum die casting molds

Energy Technology Data Exchange (ETDEWEB)

Peter, Ildiko, E-mail: ildiko.peter@polito.it; Rosso, Mario; Gobber, Federico Simone

2015-12-15

Highlights: • Development and characterization of some protective coatings on steel substrate, realized by plasma spray techniques, were presented. • The substrate material used is a Cr–Mo–V based hot work tool steel. • The main attention is on the study of wear and on the characterization of the interface, because of their key role in determining the resistance of the coating layer. • Simulation of friction and wear processes is performed by pin-on-disk test and the tested samples are observed by scanning electron microscopy. - Abstract: In this paper, the development and characterization of some protective coatings on steel substrate are presented. The coatings are realized by plasma spray techniques. The substrate material used is a Cr–Mo–V based hot work tool steel, initially submitted to vacuum heat treatment to achieve homogeneous hardness. The main attention is focused on the study of wear and on the characterization of the interface between the substrate material and the coating layer, because of their key role in determining the resistance of the coating layer. Simulation of friction and wear processes is performed by pin-on-disk test and the tested samples are observed by scanning electron microscopy.

Hardness and wear analysis of Cu/Al2O3 composite for application in EDM electrode

Science.gov (United States)

Hussain, M. Z.; Khan, U.; Jangid, R.; Khan, S.

2018-02-01

Ceramic materials, like Aluminium Oxide (Al2O3), have high mechanical strength, high wear resistance, high temperature resistance and good chemical durability. Powder metallurgy processing is an adaptable method commonly used to fabricate composites because it is a simple method of composite preparation and has high efficiency in dispersing fine ceramic particles. In this research copper and novel material aluminium oxide/copper (Al2O3/Cu) composite has been fabricated for the application of electrode in Electro-Discharge Machine (EDM) using powder metallurgy technique. Al2O3 particles with different weight percentages (0, 1%, 3% and 5%) were reinforced into copper matrix using powder metallurgy technique. The powders were blended and compacted at a load of 100MPa to produce green compacts and sintered at a temperature of 574 °C. The effect of aluminium oxide content on mass density, Rockwell hardness and wear behaviour were investigated. Wear behaviour of the composites was investigated on Die-Sink EDM (Electro-Discharge Machine). It was found that wear rate is highly depending on hardness, mass density and green protective carbonate layer formation at the surface of the composite.

A new strategy for wear and corrosion measurements using ion beam based techniques

International Nuclear Information System (INIS)

Dudu, D.; Popa, V.; Racolta, P.M.; Voiculescu, Dana

2001-01-01

TLA lies under the limit considered to be safe from the point of view of radiation protection, industry hesitates to use this technique mainly due to psychological reasons with respect to the handling of radioactive material. Recognizing this problem we have decided to offer to industry wear/corrosion measurements using TLA and UTLA in the form of a c omplete package . This means that surface activation of components in our accelerators and the subsequent wear measurements in the engine test facility are performed on the same site without the need of transportation of activated components over long distances.. This enables industry to obtain reliable wear data in a short time without building on expensive test bed and without the need of handling radioactive materials. This objective will be performed in collaboration with the specialists from CNRS-CERI Orleans -France and JRC-IAM Ispra, Italy. Some experiments in order to develop the UTLA method for wear and corrosion studies have been started. The tandem Van de Graaff accelerator - 8 MV on terminal - will be used, in this project, in order to characterize the surface layers and tribological phenomena (Cu, Sn, Ce etc. migration ) by other ion beam based techniques (RBS, NRA, PIXE, CE, HICE and ERDA techniques). (authors)

Determinants of personal protective equipment (PPE) use in UK motorcyclists: exploratory research applying an extended theory of planned behaviour.

Science.gov (United States)

Norris, Emma; Myers, Lynn

2013-11-01

Despite evident protective value of motorcycle personal protective equipment (PPE), no research has assessed considerations behind its uptake in UK riders. A cross-sectional online questionnaire design was employed, with riders (n=268) recruited from online motorcycle forums. Principal component analysis found four PPE behavioural outcomes. Theoretical factors of intentions, attitudes, injunctive and descriptive subjective norms, risk perceptions, anticipated regret, benefits and habit were also identified for further analysis. High motorcycle jacket, trousers and boots wear, middling high-visibility wear and low non-Personal Protective Equipment wear were found. Greater intentions, anticipated regret and perceived benefits were significantly associated with increased motorcycle jacket, trousers and boots wear, with habit presence and scooter use significantly associated with increased high-visibility wear. Lower intentions, anticipated regret and risk perceptions, being female, not holding a car licence and urban riding were significantly associated with increased non-PPE wear. A need for freedom of choice and mixed attitudes towards PPE use were evident in additional comments. PPE determinants in this sample provide a preliminary basis for future uptake interventions. Larger scale and qualitative research is needed to further investigate relevant constructs. Copyright © 2013 Elsevier Ltd. All rights reserved.

3D FEM Simulation of Flank Wear in Turning

Science.gov (United States)

Attanasio, Aldo; Ceretti, Elisabetta; Giardini, Claudio

2011-05-01

This work deals with tool wear simulation. Studying the influence of tool wear on tool life, tool substitution policy and influence on final part quality, surface integrity, cutting forces and power consumption it is important to reduce the global process costs. Adhesion, abrasion, erosion, diffusion, corrosion and fracture are some of the phenomena responsible of the tool wear depending on the selected cutting parameters: cutting velocity, feed rate, depth of cut, …. In some cases these wear mechanisms are described by analytical models as a function of process variables (temperature, pressure and sliding velocity along the cutting surface). These analytical models are suitable to be implemented in FEM codes and they can be utilized to simulate the tool wear. In the present paper a commercial 3D FEM software has been customized to simulate the tool wear during turning operations when cutting AISI 1045 carbon steel with uncoated tungsten carbide tip. The FEM software was improved by means of a suitable subroutine able to modify the tool geometry on the basis of the estimated tool wear as the simulation goes on. Since for the considered couple of tool-workpiece material the main phenomena generating wear are the abrasive and the diffusive ones, the tool wear model implemented into the subroutine was obtained as combination between the Usui's and the Takeyama and Murata's models. A comparison between experimental and simulated flank tool wear curves is reported demonstrating that it is possible to simulate the tool wear development.

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.......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....

Radiation protective clothing

International Nuclear Information System (INIS)

Ijiri, Yasuo; Fujinuma, Tadashi; Aso, Tsutomu.

1991-01-01

The present invention concerns radiation protective clothings suitable for medical protective clothings, aprons, etc. A primary sheet comprises a lead-incorporated organic polymer layer having a less frictional layer on one side and a contamination-resistant layer on the other side. A secondary sheet comprises a lead-incorporated organic polymer layer having a less frictional layer on one side and a comfortable skin-feeling layer on the other side. The less frictional layers of the primary and the secondary layer are laminated so as to be in contact with each other. Then, they are formed so that the comfortable skin-feeling layer of the secondary sheet is on the inner side, in other words, on the side of a wearer, and the contamination-resistant layer of the primary sheet is on the outer side. With such a constitution, although it involves the lead-incorporated organic polymer sheets of a large weight, it is comfortable to wear because of excellent flexibility and causes less feeling of fatigue even during wearing for a long period of time. (I.N.)

Sun exposure and sun protection behaviours among young adult sport competitors.

Science.gov (United States)

Lawler, Sheleigh; Spathonis, Kym; Eakin, Elizabeth; Gallois, Cindy; Leslie, Eva; Owen, Neville

2007-06-01

To explore the relationship between sun protection and physical activity in young adults (18-30 years) involved in four organised sports. Participants (n=237) in field hockey, soccer, tennis and surf sports completed a self-administered survey on demographic and sun-protective behaviours while playing sport. Differences in sun-protective behaviour were explored by sport and by gender. Sunburn during the previous sporting season was high (69%). There were differences between sports for sunburn, sunscreen use and reapplication of sunscreen. Lifesaving had the highest rates compared with the other three sports. Hats and sunglasses worn by participants varied significantly by sports. A greater proportion of soccer and hockey players indicated they were not allowed to wear a hat or sunglasses during competition. For all sports, competition was played mainly in the open with no shade provision for competitors while they were playing. There were some gender differences within each of the sports. Female soccer and tennis players were more likely to wear sunscreen compared with males. Female hockey players were more likely to wear a hat compared with males. Our findings highlight that there is still room for improvement in sun-protective behaviours among young adult sport competitors. There is a need for a systematic approach to sun protection in the sporting environments of young adults. Health promotion efforts to increase physical activity need to be paired with sun protection messages.

Evaluation of wear rate of dental composites polymerized by halogen or LED light curing units

Directory of Open Access Journals (Sweden)

Alaghehmand H.

2006-08-01

Full Text Available Background and Aim: Sufficient polymerization is a critical factor to obtain optimum physical properties and clinical efficacy of resin restorations. The aim of this study was to evaluate wear rates of composite resins polymerized by two different systems Light Emitting Diodes (LED to and Halogen lamps. Materials and Methods: In this laboratory study, 20 specimens of A3 Tetric Ceram composite were placed in brass molds of 2*10*10 mm dimensions and cured for 40 seconds with 1 mm distance from surface. 10 specimens were cured with LED and the other 10 were cured with Halogen unit. A device with the ability to apply force was developed in order to test the wear of composites. After storage in distilled water for 10 days, the specimens were placed in the wear testing machine. A chrome cobalt stylus with 1.12 mm diameter was applied against the specimens surfaces with a load of 2 kg. The weight of each samples before and after 5000, 10000, 20000, 40000, 80000 and 120000 cycles was measured using an electronic balance with precision of 10-4 grams. Data were analyzed using t test and paired t test. P0.05. Conclusion: Based on the results of this study, LED and halogen light curing units resulted in a similar wear rate in composite resin restorations.

Evaluation of commercial products for personal protection against mosquitoes.

Science.gov (United States)

Revay, Edita E; Junnila, Amy; Xue, Rui-De; Kline, Daniel L; Bernier, Ulrich R; Kravchenko, Vasiliy D; Qualls, Whitney A; Ghattas, Nina; Müller, Günter C

2013-02-01

Human landing catch studies were conducted in a semi-field setting to determine the efficacy of seven commercial products used for personal protection against mosquitoes. Experiments were conducted in two empty, insecticide free, mesh-enclosed greenhouses, in Israel, with either 1500 Aedes albopictus or 1500 Culex pipiens released on consecutive study nights. The products tested in this study were the OFF!(®) Clip-On™ Mosquito Repellent (Metofluthrin 31.2%) and the Terminix(®) ALLCLEAR(®) Sidekick Mosquito Repeller (Cinnamon oil 10.5%; Eugenol 13%; Geranium oil 21%; Peppermint 5.3%; Lemongrass oil 2.6%), which are personal diffusers; Super Band™ Wristband (22% Citronella oil) and the PIC(®) Citronella Plus Wristband (Geraniol 15%; Lemongrass oil 5%, Citronella oil 1%); the Sonic Insect Repeller Keychain; the Mosquito Guard Patch (Oil of Lemon Eucalyptus 80mg), an adhesive-backed sticker for use on textiles; and the Mosquito Patch (vitamin B1 300mg), a transdermal patch. It was determined that the sticker, transdermal patch, wristbands and sonic device did not provide significant protection to volunteers compared with the mosquito attack rate on control volunteers who were not wearing a repellent device. The personal diffusers: - OFF!(®) Clip-On™ and Terminix(®) ALLCLEAR(®) Sidekick - provided superior protection compared with all other devices in this study. These diffusers reduced biting on the arms of volunteers by 96.28% and 95.26% respectively, for Ae. albopictus, and by 94.94% and 92.15% respectively, for Cx. pipiens. In a second trial conducted to compare these devices directly, biting was reduced by the OFF!(®) Clip-On™ and the Terminix(®) ALLCLEAR(®) by 87.55% and 92.83%, respectively, for Ae. albopictus, and by 97.22% and 94.14%, respectively, for Cx. pipiens. There was no significant difference between the performances of the two diffusers for each species. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

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.

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.

Information booklet on personal protective equipment: eye and face protection

International Nuclear Information System (INIS)

1992-01-01

In all work places where hazards of various kinds are present and the same cannot be totally controlled by engineering methods, suitable personal protective equipment (PPE) shall be used. There are several types of eye and face protection devices available in the market and it is important that employees use the proper type for the particular job. The main classes of eye and face protection devices required for the industrial operations are as follows: (a) eye protection devices which includes: (i) safety goggles (ii) safety spectacles (iii) safety clipons and eye and face protection devices which are (i) eye shield, (ii) face shield, (iii) wire mesh screen guard. Guide lines for selecting appropriate ear and face protection equipment for nuclear installations are given. (M.K.V.). 4 annexures, 1 appendix

Engineering of bone fixation metal implants biointerface-Application of parylene C as versatile protective coating

Energy Technology Data Exchange (ETDEWEB)

Cieslik, Monika, E-mail: cieslik@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Institute of Metallurgy and Materials Science, PAS, W. Reymonta 25, 30-059 Krakow (Poland); Zimowski, Slawomir [AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Golda, Monika [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Institute of Metallurgy and Materials Science, PAS, W. Reymonta 25, 30-059 Krakow (Poland); Engvall, Klas [KTH Royal Institute of Technology, Department of Chemical Engineering and Technology, Division of Chemical Technology, Drottning Kristinas vaeg. 42, SE-100 44 Stockholm (Sweden); Pan, Jinshan [KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas vaeg. 51, SE-100 44 Stockholm (Sweden); Rakowski, Wieslaw [AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Kotarba, Andrzej, E-mail: kotarba@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland)

2012-12-01

The tribological and protective properties of parylene C coatings (2-20 {mu}m) on stainless steel 316L implant materials were investigated by means of electrochemical measurements and wear tests. The thickness and morphology of the CVD prepared coatings were characterized by scanning electron and laser confocal microscopy. The stability of the coatings was examined in contact with Hanks' solution and H{sub 2}O{sub 2} (simulating the inflammatory response). It was concluded that silane-parylene C coating with the optimum thickness of 8 {mu}m exhibits excellent wear resistance properties and limits the wear formation. The engineered versatile coating demonstrates sufficient elastomer properties, essential to sustain the implantation surgery strains and micromotions during long-term usage in the body. - Highlights: Black-Right-Pointing-Pointer A versatile coating for protection of metal implant surface is proposed. Black-Right-Pointing-Pointer The protective properties of 2-20 {mu}m silane-parylene C coating were examined. Black-Right-Pointing-Pointer The engineered material proves its high anticorrosive and wear resistance. Black-Right-Pointing-Pointer The practical implications of the coating properties were discussed.

Effect of dental wear, stabilization appliance and anterior tooth reconstruction on mandibular movements during speech.

Science.gov (United States)

Serrano, Priscila de Oliveira; Faot, Fernanda; Del Bel Cury, Altair Antoninha; Rodrigues Garcia, Renata Cunha Matheus

2008-01-01

This study described changes in mandibular movements during pronunciation of /m/ and /s/ sounds in Portuguese, in patients presenting dental wear before and after appliance insertion and tooth reconstruction. Subjects were divided into a control group of dentate patients and an experimental group of patients with incisal tooth wear due to bruxism. A magnetic jaw tracking device measured the jaw opening, and translations to left and right sides of the mandible during pronunciation of phonemes. Evaluations were carried out 1 week and immediately before appliance insertion; 24 h, 7, 30 and 60 days after appliance insertion; and 1 week and 1 month after tooth reconstruction. Data were submitted to two-way ANOVA, Mann-Whitney and Friedman tests (pspeech of /m/ and /s/ sounds were not changed after appliance insertion and reconstruction of teeth.

Development of the self-learning machine for creating models of microprocessor of single-phase earth fault protection devices in networks with isolated neutral voltage above 1000 V

Science.gov (United States)

Utegulov, B. B.; Utegulov, A. B.; Meiramova, S.

2018-02-01

The paper proposes the development of a self-learning machine for creating models of microprocessor-based single-phase ground fault protection devices in networks with an isolated neutral voltage higher than 1000 V. Development of a self-learning machine for creating models of microprocessor-based single-phase earth fault protection devices in networks with an isolated neutral voltage higher than 1000 V. allows to effectively implement mathematical models of automatic change of protection settings. Single-phase earth fault protection devices.

Device for protecting the containment vessel dome of a nuclear reactor

International Nuclear Information System (INIS)

Allain, A.; Filloleau, E.; Mulot, P.

1976-01-01

A device is disclosed for protecting the dome of a nuclear reactor containment vessel against the upward displacement of the concrete shield slab of said reactor and the resultant effects of tilting of an equipment unit mounted on the shield slab at the periphery of said slab, wherein said device comprises: (1) means for separating the equipment unit into two sections consisting of an upper section and a lower section, said lower section being rigidly fixed to said shield slab and said means being actuated by the upward displacement of said slab, (2) a system for vertical rectilinear guiding of said upper section within the containment vessel, and (3) rigid mechanical components which provide a coupling between the aforesaid upper and lower sections of the equipment unit and exert on said upper section under the action of the tilting motion of said lower section a thrust which causes the upward displacement of said upper section

Millisecond bearing wear

International Nuclear Information System (INIS)

Blatchley, C.; Sioshansi, P.

1987-01-01

Radionuclides have been widely used for many purposes in medicine, metals, transportation, manufacturing and research. Approximately 200 artificially produced nuclides are commercially available from reactors or accelerator sources. Another 400 or so have properties which may make them useful if satisfactory methods of production can be developed. One of the most economically important industrial applications of radionuclides has been in wear measurement and condition monitoring in reciprocating engines. The general techniques developed for this purpose have also been applied in a number of other areas besides engine or lubrication studies. The wear of floor wax applied to linoleum, for example, has been measured by mixing shortlived radionuclides in the wax. In those applications where the material is tagged and then followed, the radionuclides are termed ''tracers,'' similar to the medical tracer materials used to measure uptake or metabolism of biologically active chemicals in the body. The alternate function for the radionuclides is to act as ''markers'' which indicate the amount of material which is remaining at the location of the original activation. Both approaches require that the debris removed from the surface must be carried away from the original site. The first application of radioactive tracers as a diagnostic tool in engines was in 1949. In this technique, an entire wearing part such as a piston ring or gear was first exposed to neutrons in a nuclear reactor. This caused the entire volume of the part to become radioactive. The part was next installed and exposed to wear in the operating engine. Detectors placed near the oil line, an oil filter or a sediment trap then determined the amount of debris from the part by counting the gamma rays escaping from the debris

Influence of high sintering pressure on the microhardness and wear resistance of diamond powder and silicon carbide-based composites

Directory of Open Access Journals (Sweden)

Osipov Oleksandr Sergueevitch

2004-01-01

Full Text Available The work reported on here involved the development of several samples of "diamond-SiC" composite produced under sintering pressures of up to 9.0 GPa at temperatures of up to 1973 7K. The average size of the diamond micropowder crystals used was 40/28 µm. The sintering process was carried out in a 2500-ton hydraulic press equipped with an anvil-type high-pressure device having a toroidal work surface and a central concavity diameter of 20 mm. The microhardness and wear resistance of the samples were found to be dependent on the sintering pressure. The experimental results indicated that the maximum microhardness and minimum wear resistance coefficients of each compact were attained when the pressure applied during sintering exceeded 6.5 GPa. Based on the established values of pressure, this study served to identify the types of devices applicable for the manufacture of composite material inserts for a variety of rock drilling applications.

Evaluation of Wear on Macro-Surface Textures Generated by ns Fiber Laser

Science.gov (United States)

Harish, V.; Soundarapandian, S.; Vijayaraghavan, L.; Bharatish, A.

2018-03-01

The demand for improved performance and long term reliability of mechanical systems dictate the use of advanced materials and surface engineering techniques. A small change in the surface topography can lead to substantial improvements in the tribological behaviour of the contact surfaces. One way of altering the surface topography is by surface texturing by introducing dimples or channels on the surfaces. Surface texturing is already a successful technique which finds a wide area of applications ranging from heavy industries to small scale devices. This paper reports the effect of macro texture shapes generated using a nanosecond fiber laser on wear of high carbon chromium steel used in large size bearings having rolling contacts. Circular and square shaped dimples were generated on the surface to assess the effect of sliding velocities on friction coefficient. Graphite was used as solid lubricant to minimise the effect of wear on textured surfaces. The laser parameters such as power, scan speed and passes were optimised to obtain macro circular and square dimples which was characterised using a laser confocal microscope. The friction coefficients of the circular and square dimples were observed to lie in the same range due to minimum wear on the surface. On the contrary, at medium and higher sliding velocities, square dimples exhibited lower friction coefficient values compared to circular dimples. The morphology of textured specimen was characterised using Scanning Electron Microscope.

Tool Wear Monitoring Using Time Series Analysis

Science.gov (United States)

Song, Dong Yeul; Ohara, Yasuhiro; Tamaki, Haruo; Suga, Masanobu

A tool wear monitoring approach considering the nonlinear behavior of cutting mechanism caused by tool wear and/or localized chipping is proposed, and its effectiveness is verified through the cutting experiment and actual turning machining. Moreover, the variation in the surface roughness of the machined workpiece is also discussed using this approach. In this approach, the residual error between the actually measured vibration signal and the estimated signal obtained from the time series model corresponding to dynamic model of cutting is introduced as the feature of diagnosis. Consequently, it is found that the early tool wear state (i.e. flank wear under 40µm) can be monitored, and also the optimal tool exchange time and the tool wear state for actual turning machining can be judged by this change in the residual error. Moreover, the variation of surface roughness Pz in the range of 3 to 8µm can be estimated by the monitoring of the residual error.

Thermal Conductivity and Wear Behavior of HVOF-Sprayed Fe-Based Amorphous Coatings

Directory of Open Access Journals (Sweden)

Haihua Yao

2017-10-01

Full Text Available To protect aluminum parts in vehicle engines, metal-based thermal barrier coatings in the form of Fe59Cr12Nb5B20Si4 amorphous coatings were prepared by high velocity oxygen fuel (HVOF spraying under two different conditions. The microstructure, thermal transport behavior, and wear behavior of the coatings were characterized simultaneously. As a result, this alloy shows high process robustness during spraying. Both Fe-based coatings present dense, layered structure with porosities below 0.9%. Due to higher amorphous phase content, the coating H-1 exhibits a relatively low thermal conductivity, reaching 2.66 W/(m·K, two times lower than the reference stainless steel coating (5.85 W/(m·K, indicating a good thermal barrier property. Meanwhile, the thermal diffusivity of amorphous coatings display a limited increase with temperature up to 500 °C, which guarantees a steady and wide usage on aluminum alloy. Furthermore, the amorphous coating shows better wear resistance compared to high carbon martensitic GCr15 steel at different temperatures. The increased temperature accelerating the tribological reaction, leads to the friction coefficient and wear rate of coating increasing at 200 °C and decreasing at 400 °C.

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.

Wear-triggered self-healing behavior on the surface of nanocrystalline nickel aluminum bronze/Ti3SiC2 composites

Science.gov (United States)

Zhai, Wenzheng; Lu, Wenlong; Zhang, Po; Wang, Jian; Liu, Xiaojun; Zhou, Liping

2018-04-01

Self-healing can protect materials from diverse damages, but is intrinsically difficult in metals. This paper demonstrates a potential method through a simultaneous decomposition and oxidation of Ti3SiC2 to achieve healing of stress cracking on the surface of nickel aluminum bronze (NAB)/Ti3SiC2 nanocrystalline composites during fretting wear. At the finest nanocrystalline materials, a crack recovery would be attained at 76.5%. The repetitive fretting wear leads to a modest amount of 'flowability' of Ti3SiC2 toward the crack, facilitating crack recovery. Along with the wear-triggered self-healing, the NAB/Ti3SiC2 shows an improved tribological performance with the stable decreased friction torque due to the formation of lubrication TiO2 oxide.

Power Cycling Test Method for Reliability Assessment of Power Device Modules in Respect to Temperature Stress

DEFF Research Database (Denmark)

Choi, Ui-Min; Blaabjerg, Frede; Jørgensen, Søren

2018-01-01

Power cycling test is one of the important tasks to investigate the reliability performance of power device modules in respect to temperature stress. From this, it is able to predict the lifetime of a component in power converters. In this paper, representative power cycling test circuits......, measurement circuits of wear-out failure indicators as well as measurement strategies for different power cycling test circuits are discussed in order to provide the current state of knowledge of this topic by organizing and evaluating current literature. In the first section of this paper, the structure...... of a conventional power device module and its related wear-out failure mechanisms with degradation indicators are discussed. Then, representative power cycling test circuits are introduced. Furthermore, on-state collector-emitter voltage (VCE ON) and forward voltage (VF) measurement circuits for wear-out condition...

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.

Truck tyre wear assessment and prediction

NARCIS (Netherlands)

Lupker, H.A.; Montanaro, F.; Donadio, D.; Gelosa, E.; Vis, M.A.

2002-01-01

Tyre wear is a complex phenomenon. It depends non-linearly on numerous parameters, like tyre compound and design, vehicle type and usage, road conditions and road surface characteristics, environmental conditions (e.g., temperature) and many others. Yet, tyre wear has many economic and ecological

Steam generator fretting-wear damage: A summary of recent findings

International Nuclear Information System (INIS)

Guerout, F.M.; Fisher, N.J.

1999-01-01

Flow-induced vibration of steam generator (SG) tubes may sometimes result in fretting-wear damage at the tube-to-support locations. Fretting-wear damage predictions are largely based on experimental data obtained at representative test conditions. Fretting-wear of SG materials has been studied at the Chalk River Laboratories for two decades. Tests are conducted in fretting-wear test machines that simulate SG environmental conditions and tube-to-support dynamic interactions. A new high-temperature force and displacement measuring system was developed to monitor tube-to-support interaction (i.e., work-rate) at operating conditions. This improvement in experimental fretting-wear technology was used to perform a comprehensive study of the effect of various environment and design parameters on SG tube wear damage. This paper summarizes the results of tests performed over the past 4 yr to study the effect of temperature, water chemistry, support geometry, and tube material on fretting-wear. The results show a significant effect of temperature on tube wear damage. Therefore, fretting-wear tests must be performed at operating temperatures in order to be relevant. No significant effect of the type of water treatment on tube wear damage was observed. For predominantly impacting motion, the wear of SG tubes in contact with 410 stainless steel is similar regardless of whether Alloy 690 or Alloy 800 is used as tubing material or whether lattice bars or broached hole supports are used. Based on results presented in this paper, an average wear coefficient value is recommended that is used for the prediction of SG tube wear depth versus time

Grain size dependence of wear in ceramics

International Nuclear Information System (INIS)

Wu, C.C.; Rice, R.W.; Johnson, D.; Platt, B.A.

1985-01-01

Pin-On-Disk (POD), microwear tests of Al 2 O 3 , MgO, MgAl 2 O 4 , and ZrO 2 , most being dense and essentially single phase, showed the reciprocal of wear following a hall-petch type relationship. However, extrapolation to infinite grain size always gave a lower intercept than most or all single-crystal values; in particular, Al 2 O 3 data projects to a negative intercept. Initial macro wear tests of some of the same Al 2 O 3 materials also indicate a hall-petch type grain-size dependence, but with a greatly reduced grain-size dependence, giving a positive hall-petch intercept. Further, the macrowear grain-size dependence appears to decrease with increased wear. It is argued that thermal expansion anisotropy (of Al 2 O 3 ) significantly affects the grain size dependence of POD wear, in particular, giving a negative intercept, while elastic anisotropy is suggested as a factor in the grain-size dependence of the cubic (MgO, MgAl 2 O 4 , and ZrO 2 ) materials. The reduced grain-size dependence in the macrowear tests is attributed to overlapping wear tracks reducing the effects of enhanced wear damage, e.g., from elastic and thermal expansion anisotropies

Tool wear modeling using abductive networks

Science.gov (United States)

Masory, Oren

1992-09-01

A tool wear model based on Abductive Networks, which consists of a network of `polynomial' nodes, is described. The model relates the cutting parameters, components of the cutting force, and machining time to flank wear. Thus real time measurements of the cutting force can be used to monitor the machining process. The model is obtained by a training process in which the connectivity between the network's nodes and the polynomial coefficients of each node are determined by optimizing a performance criteria. Actual wear measurements of coated and uncoated carbide inserts were used for training and evaluating the established model.

Wear mechanisms of coated hardmetals

International Nuclear Information System (INIS)

Richter, V.

2001-01-01

In the paper several aspects of the wear mechanisms of coated hardmetals, ceramics and super-hard materials (CBN) in machining cast iron are discussed, with particular attention being given to high-speed machining of different cast iron grades. The influence of machining parameters, microstructure, composition and mechanical and chemical properties of the cutting tool and the work-piece material on wear are considered. (author)

Evaluation of protective gloves and working techniques for reducing hand-arm vibration exposure in the workplace.

Science.gov (United States)

Milosevic, Matija; McConville, Kristiina M Valter

2012-01-01

Operation of handheld power tools results in exposure to hand-arm vibrations, which over time lead to numerous health complications. The objective of this study was to evaluate protective equipment and working techniques for the reduction of vibration exposure. Vibration transmissions were recorded during different work techniques: with one- and two-handed grip, while wearing protective gloves (standard, air and anti-vibration gloves) and while holding a foam-covered tool handle. The effect was examined by analyzing the reduction of transmitted vibrations at the wrist. The vibration transmission was recorded with a portable device using a triaxial accelerometer. The results suggest large and significant reductions of vibration with appropriate safety equipment. Reductions of 85.6% were achieved when anti-vibration gloves were used. Our results indicated that transmitted vibrations were affected by several factors and could be measured and significantly reduced.

Investigation of Wear Behavior of Aluminum Matrix Composite Reinforced by Al2O3 and Produced by Hot Pressing Process

Directory of Open Access Journals (Sweden)

Halil ARIK

2017-12-01

Full Text Available In this study, Al powder produced by gas atomization technique has 72.06 µm average particle size and 99 % purity was mixed with as a reinforcement Al2O3 has 99.52% purity and 45 submicron particle size in a high energy ball mill for two hours. In order to obtain disk samples with 30 mm diameter and 6 mm thick mixed powders, after the characterization of particle size and morphology, were compacted in a single action press. Compaction process were carried out from mixed powders by hot pressing at 200 MPa pressure and 550 °C temperature for two hours. Then microstructural analysis, hardness and density measurements of powder metal composite parts were performed. After, the characterization of samples abrasion wear tests were performed according to ASTM-G99-05 by using TRIBOMETER T10/20 ball-on-disk abrasive wearing device. After the abrasive wear test of aluminum and composite powder metal parts produced under the identical test parameters, test results were compared and effect of Al2O3 on the wear properties of composite materials was exhibited. The test results showed that the composite parts have 62 % extra harness and better abrasion wear performance according to aluminum powder metal parts produced and tested under the identical conditions

Nuclear reactor safety protection device

International Nuclear Information System (INIS)

Okido, Fumiyasu; Noguchi, Atomi; Matsumiya, Shoichi; Furusato, Ken-ichiro; Arita, Setsuo.

1994-01-01

The device of the present invention extremely reduces a probability of causing unnecessary scram of a nuclear reactor. That is, four control devices receive signals from each of four sensors and output four trip signals respectively in a quardruplicated control device. Each of the trip signals and each of trip signals via a delay circuit are inputted to a logical sum element. The output of the logical sum circuit is inputted to a decision of majority circuit. The decision of majority circuit controls a scram pilot valve which conducts scram of the reactor by way of a solenoid coils. With such procedures, even if surge noises of a short pulse width are mixed to the sensor signals and short trip signals are outputted, there is no worry that the scram pilot valve is actuated. Accordingly, factors of lowering nuclear plant operation efficiency due to erroneous reactor scram can be reduced. (I.S.)

Geotribology - Friction, wear, and lubrication of faults

Science.gov (United States)

Boneh, Yuval; Reches, Ze'ev

2018-05-01

We introduce here the concept of Geotribology as an approach to study friction, wear, and lubrication of geological systems. Methods of geotribology are applied here to characterize the friction and wear associated with slip along experimental faults composed of brittle rocks. The wear in these faults is dominated by brittle fracturing, plucking, scratching and fragmentation at asperities of all scales, including 'effective asperities' that develop and evolve during the slip. We derived a theoretical model for the rate of wear based on the observation that the dynamic strength of brittle materials is proportional to the product of load stress and loading period. In a slipping fault, the loading period of an asperity is inversely proportional to the slip velocity, and our derivations indicate that the wear-rate is proportional to the ratio of [shear-stress/slip-velocity]. By incorporating the rock hardness data into the model, we demonstrate that a single, universal function fits wear data of hundreds of experiments with granitic, carbonate and sandstone faults. In the next step, we demonstrate that the dynamic frictional strength of experimental faults is well explained in terms of the tribological parameter PV factor (= normal-stress · slip-velocity). This factor successfully delineates weakening and strengthening regimes of carbonate and granitic faults. Finally, our analysis revealed a puzzling observation that wear-rate and frictional strength have strikingly different dependencies on the loading conditions of normal-stress and slip-velocity; we discuss sources for this difference. We found that utilization of tribological tools in fault slip analyses leads to effective and insightful results.

Interventions to promote the wearing of hearing protection

NARCIS (Netherlands)

El Dib, R. P.; Verbeek, J.; Atallah, A. N.; Andriolo, R. B.; Soares, B. G. O.

2006-01-01

Background Noise induced hearing loss can only be prevented by eliminating or lowering noise exposure levels. Where the source of the noise can not be eliminated workers have to rely on hearing protective equipment. Several trials have been conducted to study the effectiveness of interventions to

Straylight Measurements in Contact Lens Wear

NARCIS (Netherlands)

van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

2010-01-01

Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

On-field evaluation of operator lens protective devices in interventional radiology

International Nuclear Information System (INIS)

Strocchi, S.; Chiaravalli, A.; Veronese, I.; Novario, R.

2016-01-01

The recent publication of the Euratom Directive 2013/59, adopting the reduction of eye lens dose limits from 150 to 20 mSv y"-"1, calls for the development of new tools and methodologies for evaluating the eye lens dose absorbed by the medical staff involved in interventional radiology practices. Moreover, the effectiveness of the protective devices, like leaded glasses, which can be employed for radiation protection purposes, must be tested under typical exposure scenarios. In this work, eye lens dose measurements were carried out on an anthropomorphic phantom simulating a physician bound to perform standard interventional neuroradiology angiographic procedures. The correlation between eye lens doses, in terms of Hp(0.07), and the equivalent dose [again in terms of Hp(0.07)] monthly measured with thermoluminescent dosemeters placed above the lead apron at the chest level was studied, in the presence and in the absence of different types of leaded glasses. (authors)

Impact fretting wear in CO2-based environments

International Nuclear Information System (INIS)

Levy, G.; Morri, J.

1985-01-01

An impact wear model, based on the load-sliding distance proportionality of wear and the mechanical response of the impacting bodies, was derived and tested against experiment. The experimental work was carried out on a twin vibrator rig capable of repetitive impact of a moving specimen against a stationary target material. The impact wear characteristics of three materials (mild steel, 9Cr-1Mo steel and austenitic 316 steel) against 310 stainless steel were examined over a range of temperatures (18-600 0 C). Additionally the effects of variations in the mechanical parameters (incident energy, ξ i , number N of impacts and angle of incidence φ) as a function of temperature were evaluated for mild steel only. The model was verified for impacting within a stable wear regime at 100 0 C for 9Cr-1Mo steel. The emergence of a severe-to-mild wear transition at elevated temperatures (200-400 0 C), however, introduced an energy and a 'numbers of cycles' effect that caused apparent deviations from theory. It was concluded that for stable single-mechanism wear regimes (metallic, oxidative etc.) oblique elastic impacts with a gross slip component were accurately described by the proposed impact wear model. (orig.)

Aspects of fretting wear of sprayed cermet coatings

International Nuclear Information System (INIS)

Chivers, T.C.

1985-01-01

Two experimental fretting programmes which investigated aspects of fretting wear of sprayed cermet coatings are reviewed. These programmes were conducted in support of components used in the advanced gas-cooled reactor. It is speculated that the results from these programmes are compatible with a simple two-stage wear model. This model assumes that an initial wear process occurs which is dominated by an interlocking and removal of asperities. Such a phase will be dependent on the superficial contact areas and possibly the interfacial load, but the latter aspect is not considered. This initial wear is of very short duration and is followed by a mild, oxidative, wear mode. Coatings data are also compared with those for structural steels. In short-term low temperature tests it appears that structural steels have comparable performance with the cermet coatings but it is argued that this is an artefact of the wear process. However, at high temperatures (600 0 C) wear of stainless steel could not be determined, the specimens showing a net weight gain. It is concluded that for in-reactor fretting applications cermet coatings will have advantages over structural steels at low temperatures. Even in high temperature regions some operation at low temperatures is experienced and consequently cermet coatings may be useful here also. (orig.)

Potential countersample materials for in vitro simulation wear testing.

Science.gov (United States)

Shortall, Adrian C; Hu, Xiao Q; Marquis, Peter M

2002-05-01

Any laboratory investigation of the wear resistance of dental materials needs to consider oral conditions so that in vitro wear results can be correlated with in vivo findings. The choice of the countersample is a critical factor in establishing the pattern of tribological wear and in achieving an efficient in vitro wear testing system. This research investigated the wear behavior and surface characteristics associated with three candidate countersample materials used for in vitro wear testing in order to identify a possible suitable substitute for human dental enamel. Three candidate materials, stainless steel, steatite and dental porcelain were evaluated and compared to human enamel. A variety of factors including hardness, wear surface evolution and frictional coefficients were considered, relative to the tribology of the in vivo situation. The results suggested that the dental porcelain investigated bore the closest similarity to human enamel of the materials investigated. Assessment of potential countersample materials should be based on the essential tribological simulation supported by investigations of mechanical, chemical and structural properties. The selected dental porcelain had the best simulating ability among the three selected countersample materials and this class of material may be considered as a possible countersample material for in vitro wear test purposes. Further studies are required, employing a wider range of dental ceramics, in order to optimise the choice of countersample material for standardized in vitro wear testing.

Plasma sprayed TiC coatings for first wall protection in fusion devices

International Nuclear Information System (INIS)

Groot, P.; Laan, J.G. van der; Laas, L.; Mack, M.; Dvorak, M.

1989-01-01

For protection of plasma facing components in nuclear fusion devices thick titanium carbide coatings are being developed. Coatings have been produced by plasma spraying at atmospheric pressure (APS) and low pressure (LPPS) and analyzed with respect to microstructure and chemical composition. Thermo-mechanical evaluation has been performed by applying short pulse laser heat flux tests. The influence of coating thickness and porosity on the resistance to spalling by thermal shocks appears to be more important than aspects of chemical composition. (author)

Microstructure and wear resistance of laser cladded Ni-Cr-Co-Ti-V high-entropy alloy coating after laser remelting processing

Science.gov (United States)

Cai, Zhaobing; Cui, Xiufang; Liu, Zhe; Li, Yang; Dong, Meiling; Jin, Guo

2018-02-01

An attempt, combined with the technologies of laser cladding and laser remelting, has been made to develop a Ni-Cr-Co-Ti-V high entropy alloy coating. The phase composition, microstructure, micro-hardness and wear resistance (rolling friction) were studied in detail. The results show that after laser remelting, the phase composition remains unchanged, that is, as-cladded coating and as-remelted coatings are all composed of (Ni, Co)Ti2 intermetallic compound, Ti-rich phase and BCC solid solution phase. However, after laser remelting, the volume fraction of Ti-rich phase increases significantly. Moreover, the micro-hardness is increased, up to ∼900 HV at the laser remelting parameters: laser power of 1 kW, laser spot diameter of 3 mm, and laser speed of 10 mm/s. Compared to the as-cladded high-entropy alloy coating, the as-remelted high-entropy alloy coatings have high friction coefficient and low wear mass loss, indicating that the wear resistance of as-remelted coatings is improved and suggesting practical applications, like coatings on brake pads for wear protection. The worn surface morphologies show that the worn mechanism of as-cladded and as-remelted high-entropy alloy coatings are adhesive wear.

A model for predicting wear rates in tooth enamel.

Science.gov (United States)

Borrero-Lopez, Oscar; Pajares, Antonia; Constantino, Paul J; Lawn, Brian R

2014-09-01

It is hypothesized that wear of enamel is sensitive to the presence of sharp particulates in oral fluids and masticated foods. To this end, a generic model for predicting wear rates in brittle materials is developed, with specific application to tooth enamel. Wear is assumed to result from an accumulation of elastic-plastic micro-asperity events. Integration over all such events leads to a wear rate relation analogous to Archard׳s law, but with allowance for variation in asperity angle and compliance. The coefficient K in this relation quantifies the wear severity, with an arbitrary distinction between 'mild' wear (low K) and 'severe' wear (high K). Data from the literature and in-house wear-test experiments on enamel specimens in lubricant media (water, oil) with and without sharp third-body particulates (silica, diamond) are used to validate the model. Measured wear rates can vary over several orders of magnitude, depending on contact asperity conditions, accounting for the occurrence of severe enamel removal in some human patients (bruxing). Expressions for the depth removal rate and number of cycles to wear down occlusal enamel in the low-crowned tooth forms of some mammals are derived, with tooth size and enamel thickness as key variables. The role of 'hard' versus 'soft' food diets in determining evolutionary paths in different hominin species is briefly considered. A feature of the model is that it does not require recourse to specific material removal mechanisms, although processes involving microplastic extrusion and microcrack coalescence are indicated. Published by Elsevier Ltd.

Development of wear-resistant coatings for cobalt-base alloys

International Nuclear Information System (INIS)

Cockeram, B.V.

1999-01-01

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

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

Asperity-Level Origins of Transition from Mild to Severe Wear

Science.gov (United States)

Aghababaei, Ramin; Brink, Tobias; Molinari, Jean-François

2018-05-01

Wear is the inevitable damage process of surfaces during sliding contact. According to the well-known Archard's wear law, the wear volume scales with the real contact area and as a result is proportional to the load. Decades of wear experiments, however, show that this relation only holds up to a certain load limit, above which the linearity is broken and a transition from mild to severe wear occurs. We investigate the microscopic origins of this breakdown and the corresponding wear transition at the asperity level. Our atomistic simulations reveal that the interaction between subsurface stress fields of neighboring contact spots promotes the transition from mild to severe wear. The results show that this interaction triggers the deep propagation of subsurface cracks and the eventual formation of large debris particles, with a size corresponding to the apparent contact area of neighboring contact spots. This observation explains the breakdown of the linear relation between the wear volume and the normal load in the severe wear regime. This new understanding highlights the critical importance of studying contact beyond the elastic limit and single-asperity models.

Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel

Directory of Open Access Journals (Sweden)

S. Ilaiyavel

2013-03-01

Full Text Available In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear loss and wear coefficient were evaluated through pin on disc test using a sliding velocity of 3.0 m/s under normal load of 40 N and controlled condition of temperature and humidity. Based on the results of the wear test, the Heat treated Manganese Phosphate with oil lubricant exhibited the lowest average wear coefficient and the lowest wear loss under 40 N load.

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...

Investigation on wear characteristic of biopolymer gear

Science.gov (United States)

Ghazali, Wafiuddin Bin Md; Daing Idris, Daing Mohamad Nafiz Bin; Sofian, Azizul Helmi Bin; Basrawi, Mohamad Firdaus bin; Khalil Ibrahim, Thamir

2017-10-01

Polymer is widely used in many mechanical components such as gear. With the world going to a more green and sustainable environment, polymers which are bio based are being recognized as a replacement for conventional polymers based on fossil fuel. The use of biopolymer in mechanical components especially gear have not been fully explored yet. This research focuses on biopolymer for spur gear and whether the conventional method to investigate wear characteristic is applicable. The spur gears are produced by injection moulding and tested on several speeds using a custom test equipment. The wear formation such as tooth fracture, tooth deformation, debris and weight loss was observed on the biopolymer spur gear. It was noted that the biopolymer gear wear mechanism was similar with other type of polymer spur gears. It also undergoes stages of wear which are; running in, linear and rapid. It can be said that the wear mechanism of biopolymer spur gear is comparable to fossil fuel based polymer spur gear, thus it can be considered to replace polymer gears in suitable applications.

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.

Wear reduction through piezoelectrically-assisted ultrasonic lubrication

International Nuclear Information System (INIS)

Dong, Sheng; J Dapino, Marcelo

2014-01-01

Traditional lubricants are undesirable in harsh aerospace environments and certain automotive applications. Ultrasonic vibrations can be used to reduce and modulate the effective friction coefficient between two sliding surfaces. This paper investigates the relationship between friction force reduction and wear reduction in ultrasonically lubricated surfaces. A pin-on-disc tribometer is modified through the addition of a piezoelectric transducer which vibrates the pin at 22 kHz in the direction perpendicular to the rotating disc surface. Friction and wear metrics including volume loss, surface roughness, friction forces and apparent stick-slip effects are measured without and with ultrasonic vibrations at three different sliding velocities. SEM imaging and 3D profilometry are used to characterize the wear surfaces and guide model development. Over the range of speeds considered, ultrasonic vibrations reduce the effective friction force up to 62% along with a wear reduction of up to 49%. A simple cube model previously developed to quantify friction force reduction is implemented which describes wear reduction within 15% of the experimental data. (paper)

Estimating Wear Of Installed Ball Bearings

Science.gov (United States)

Keba, John E.; Mcvey, Scott E.

1993-01-01

Simple inspection and measurement technique makes possible to estimate wear of balls in ball bearing, without removing bearing from shaft on which installed. To perform measurement, one observes bearing cage while turning shaft by hand to obtain integral number of cage rotations and to measure, to nearest 2 degrees, number of shaft rotations producing cage rotations. Ratio between numbers of cages and shaft rotations depends only on internal geometry of bearing and applied load. Changes in turns ratio reflect changes in internal geometry of bearing provided measurements made with similar bearing loads. By assuming all wear occurs on balls, one computes effective value for this wear from change in turns ratio.

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.

Improvement of the protection devices for JT-60U LHRF antenna system

International Nuclear Information System (INIS)

Suzuki, Sadaaki; Seki, Masami; Shinozaki, Shinichi; Sato, Fumiaki; Hiranai, Shinichi; Hasegawa, Koichi; Moriyama, Shinichi; Ishii, Kazuhiro

2007-09-01

In the experiments featuring lower hybrid range of frequency (LHRF) system in JT-60U, carbon grills were attached to the plasma-facing part of the antenna in order to avoid the damage by the excessive heat load from the plasma. However some electric discharge traces were found there in the observation after the experiments. To avoid such discharges, improvements of the arc detector and the protection interlock by visible picture detection were tackled. In the arc detector, the amplification circuit was improved in order to obtain shorter response time and higher resolution of optical detection. Moreover, in visible picture detection, a new function of RF-on/off control utilizing PC image processing was added to distinguish the light of the arc from one of the plasma. This report summarizes improvement of the protection interlock device in a LHRF heating system. (author)

The Role of Ethological Observation for Measuring Animal Reactions to Biotelemetry Devices

OpenAIRE

Paci, Patrizia; Mancini, Clara; Price, Blaine

2017-01-01

This paper presents a methodological approach used to assess the wearability of biotelemetry devices in animals. A detailed protocol to gather quantitative and qualitative ethological observations was adapted and tested in an experimental study of 13 cat participants wearing two different GPS devices. The aim was twofold: firstly, to ascertain the potential interference generated by the devices on the animal body and behavior by quantifying and characterizing it; secondly, to individuate devi...

Multiscale Modeling of Wear Degradation

KAUST Repository

Moraes, Alvaro; Ruggeri, Fabrizio; Tempone, Raul; Vilanova, Pedro

2016-01-01

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.

Multiscale Modeling of Wear Degradation

KAUST Repository

Moraes, Alvaro; Ruggeri, Fabrizio; Tempone, Raul; Vilanova, Pedro

2015-01-01

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.

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.

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.

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.

Parameter Estimation of a Delay Time Model of Wearing Parts Based on Objective Data

Directory of Open Access Journals (Sweden)

Y. Tang

2015-01-01

Full Text Available The wearing parts of a system have a very high failure frequency, making it necessary to carry out continual functional inspections and maintenance to protect the system from unscheduled downtime. This allows for the collection of a large amount of maintenance data. Taking the unique characteristics of the wearing parts into consideration, we establish their respective delay time models in ideal inspection cases and nonideal inspection cases. The model parameters are estimated entirely using the collected maintenance data. Then, a likelihood function of all renewal events is derived based on their occurring probability functions, and the model parameters are calculated with the maximum likelihood function method, which is solved by the CRM. Finally, using two wearing parts from the oil and gas drilling industry as examples—the filter element and the blowout preventer rubber core—the parameters of the distribution function of the initial failure time and the delay time for each example are estimated, and their distribution functions are obtained. Such parameter estimation based on objective data will contribute to the optimization of the reasonable function inspection interval and will also provide some theoretical models to support the integrity management of equipment or systems.

Investigation of friction and wear characteristics of palm biodiesel

International Nuclear Information System (INIS)

Fazal, M.A.; Haseeb, A.S.M.A.; Masjuki, H.H.

2013-01-01

Highlights: ► Both wear and friction decrease with the increase of biodiesel concentration. ► Wear and friction appear to decrease more at the range of 10–20% biodiesel in diesel blend. ► The wear of steel ball in biodiesel (B100) was 20% lower than that in diesel (B0). ► Lubricity in terms of wear and friction decreases with the increase of rotating speed. - Abstract: Use of biodiesel in automobile engine is creating tribology related new challenges. The present study aims to assess the friction and wear characteristics of palm biodiesel at different concentration level by using four-ball wear machine. The investigated fuels were biodiesel (B100), diesel (B0) and three different biodiesel blends such as B10 (10% biodiesel in diesel), B20, B50. Tests were conducted at 75 °C under a normal load of 40 kg for 1 h at four different speeds viz, 600, 900, 1200 and 1500 rpm. Worn surfaces of the balls were examined by SEM. Results showed that wear and friction decreased with the increase of biodiesel concentration. The wear of steel ball in B100 was appeared to be 20% lower than that in diesel (B0)

PVC gel soft actuator-based wearable assist wear for hip joint support during walking

Science.gov (United States)

Li, Yi; Hashimoto, Minoru

2017-12-01

Plasticized polyvinyl chloride (PVC) gel and mesh electrode-based soft actuators have considerable potential to provide new types of artificial muscle, exhibiting similar responsiveness to biological muscle in air, >10% deformation, >90 kPa output stress, variable stiffness, long cycle life (>5 million cycles), and low power consumption. We have designed and fabricated a prototype of walking assist wear using the PVC gel actuator in previous study. The system has several advantages compared with traditional motor-based exoskeletons, including lower weight and power consumption, and no requirement for rigid external structures that constrain the wearer’s joints. In this study, we designed and established a control and power system to making the whole system portable and wearable outdoors. And we designed two control strategies based on the characteristics of the assist wear and the biological kinematics. In a preliminary experimental evaluation, a hemiparetic stroke patient performed a 10 m to-and-fro straight line walking task with and without assist wear on the affected side. We found that the assist wear enabled natural movement, increasing step length and decreasing muscular activity during straight line walking. We demonstrated that the assistance effect could be adjusted by controlling the on-off time of the PVC gel soft actuators. The results show the effectiveness of the proposed system and suggest the feasibility of PVC gel soft actuators for developing practical soft wearable assistive devices, informing the development of future wearable robots and the other soft actuator technologies for human movement assistance and rehabilitation.

The use of protective gloves by medical personnel.

Science.gov (United States)

Garus-Pakowska, Anna; Sobala, Wojciech; Szatko, Franciszek

2013-06-01

To minimize the risk of cross-infection between the patient and the medical staff, it is necessary to use individual protective measures such as gloves. According to the recommendations of the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), protective gloves should always be used upon contact with blood, mucosa, injured skin or other potentially infectious material. The aim of the study was to evaluate, through quasi-observation, the use of protective gloves by medical staff according to the guidelines issued by the CDC and WHO. The results were subject to statistical analysis (p gloves is demanded from the medical staff. The overall percentage of the observance of using gloves was 50%. The use of gloves depended significantly on the type of ward, profession, performed activity, number of situations that require wearing gloves during the observation unit and the real workload. During the entire study, as many as 718 contacts with patients were observed in which the same gloves were used several times. Wearing disposable protective gloves by the medical staff is insufficient.

Wear analysis of disc cutters of full face rock tunnel boring machine

Science.gov (United States)

Zhang, Zhaohuang; Meng, Liang; Sun, Fei

2014-11-01

Wear is a major factor of disc cutters' failure. No current theory offers a standard for the prediction of disc cutter wear yet. In the field the wear prediction method commonly used is based on the excavation length of tunnel boring machine(TBM) to predict the disc cutter wear and its wear law, considering the location number of each disc cutter on the cutterhead(radius for installation); in theory, there is a prediction method of using arc wear coefficient. However, the preceding two methods have their own errors, with their accuracy being 40% or so and largely relying on the technicians' experience. Therefore, radial wear coefficient, axial wear coefficient and trajectory wear coefficient are defined on the basis of the operating characteristics of TBM. With reference to the installation and characteristics of disc cutters, those coefficients are modified according to penetration, which gives rise to the presentation of comprehensive axial wear coefficient, comprehensive radial wear coefficient and comprehensive trajectory wear coefficient. Calculation and determination of wear coefficients are made with consideration of data from a segment of TBM project(excavation length 173 m). The resulting wear coefficient values, after modification, are adopted to predict the disc cutter wear in the follow-up segment of the TBM project(excavation length of 5621 m). The prediction results show that the disc cutter wear predicted with comprehensive radial wear coefficient and comprehensive trajectory wear coefficient are not only accurate(accuracy 16.12%) but also highly congruous, whereas there is a larger deviation in the prediction with comprehensive axial wear coefficient(accuracy 41%, which is in agreement with the prediction of disc cutters' life in the field). This paper puts forth a new method concerning prediction of life span and wear of TBM disc cutters as well as timing for replacing disc cutters.

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.)

Microwave warning device

International Nuclear Information System (INIS)

Shriner, W.

1981-01-01

A device for warning a person carrying or wearing it of the presence of dangerous microwave radiation is fully powered by the radiations being detected. A very low-wattage gas-discharge lamp is energized by a broadly or a sharply tuned receiver circuit including dipole antennas or one antenna and a ''grounding'' casing element. The casing may be largely and uniformly transparent or have different areas gradedly light-transmissive to indicate varying radiation intensities. The casing can be made in the shape of a pocket watch, fountain pen, bracelet or finger ring, etc

Days individual equipment of protection and professional risks; Equipements de protection individuelle et risques professionnelles

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

The personal protection equipment is studied in the legal way (legal liabilities, certification, European texts), technical way (ergonomics, painfulness of ventilated equipment wearing, reliability of a respirable air line, protection gloves against the chemical risk, exposure to nano particulates, working in hot area), human factors (hostile area and emotion management), studies on personal equipment such evaluation, efficiency, conception of new equipment, physiological tolerance, limit of use, and some general safety studies on the working places. (N.C.)

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.

Wear properties of metal ion implanted 4140 steel

International Nuclear Information System (INIS)

Evans, P.J.; Paoloni, F.J.

1994-01-01

AISI type 4140 (high tensile) steel has been implanted with tungsten and titanium using a metal vapour vacuum arc ion source. Doses in the range (1-5)x10 16 ionscm -2 were implanted to a depth of approximately 30nm. The relative wear resistance between non-implanted and implanted specimens has been estimated using pin-on-disc and abrasive wear tests. Implantation of titanium decreased the area of wear tracks by a factor of 5 over unimplanted steel. In some cases the steel was also hardened by a liquid carburization treatment before implantation. Abrasion tests revealed a further improvement in wear resistance on this material following ion irradiation. ((orig.))

Assessment of fretting wear in Hanaro fuel

International Nuclear Information System (INIS)

Chae, Hee Taek; Lim, Kyeong Hwan; Kim, Hark Rho

1999-06-01

Since the first fuel loading on Feb. 1995, various zero-power tests were performed in HANARO and power ascending tests followed. After the initial fuel loading, Hanaro operation staffs inspected only two fuel bundles which were evaluated to have the highest power at the end of each cycle and they did not recognize anything peculiar in the inspected bundles. At the end of 1996, Hanaro staffs found severe wear damages in the fuel components. After that, the 4th cycle core was re-arranged with fresh fuels only to investigate wear phenomena on the fuel components. The fuel inspections have been performed 25 times periodically since the core re-configuration. In this report, fretting wear characteristics of the fuel assemblies were evaluated and summarized. Wear damages of the improved fuel assembly to resolve the wear problem were compared with those of the original fuel assembly. Based on the results of the fuel inspections, we suggest that fuel inspection need not be done for the first 60 pump operation days in order to reduce the potential of damage by a fuel handling error and an operator's burden of the fuel inspection. (author). 6 refs., 10 tabs., 5 figs

Erosive and Mechanical Tooth Wear in Viking Age Icelanders.

Science.gov (United States)

Richter, Svend; Eliasson, Sigfus Thor

2017-08-29

(1) Background: The importance of the Icelandic Sagas as a source of information about diet habits in medieval Iceland, and possibly other Nordic countries, is obvious. Extensive tooth wear in archaeological material worldwide has revealed that the main cause of this wear is believed to have been a coarse diet. Near the volcano Hekla, 66 skeletons dated from before 1104 were excavated, and 49 skulls could be evaluated for tooth wear. The purpose of this study was to determine the main causes of tooth wear in light of diet and beverage consumption described in the Sagas; (2) Materials and methods: Two methods were used to evaluate tooth wear and seven for age estimation; (3) Results: Extensive tooth wear was seen in all of the groups, increasing with age. The first molars had the highest score, with no difference between sexes. These had all the similarities seen in wear from a coarse diet, but also presented with characteristics that are seen in erosion in modern Icelanders, through consuming excessive amounts of soft drinks. According to the Sagas, acidic whey was a daily drink and was used for the preservation of food in Iceland, until fairly recently; (4) Conclusions: It is postulated that the consumption of acidic drinks and food, in addition to a coarse and rough diet, played a significant role in the dental wear seen in ancient Icelanders.

Cerebral Ischemia Detected with Diffusion-Weighted MR Imaging after Protected Carotid Artery Stenting: Comparison of Distal Balloon and Filter Device

Energy Technology Data Exchange (ETDEWEB)

Kim, Suk Jung; Jeon, Pyoung [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Roh, Hong Gee [Konkuk University Hospital, Seoul (Korea, Republic of)] (and others)

2007-08-15

The aim of this study was to examine the incidence of ischemia during protected carotid artery stenting (CAS) as well as to compare the protective efficacy of the balloon and filter devices on diffusion-weighted MR imaging (DWI). Seventy-one consecutive protected CAS procedures in 70 patients with a severe (> 70%) or symptomatic moderate (> 50%) carotid artery stenosis were examined. A balloon device (PercuSurge GuardWire) and a filter device (FilterWire EX/EZ, Emboshield) was used in 33 cases (CAS-B group) and 38 cases (CAS-F group) to prevent distal embolization, respectively. All the patients underwent DWI within seven days before and after the procedures. The number of new cerebral ischemic lesions on the post-procedural DWI were counted and divided into ipsilateral and contralateral lesions according to the relationship with the stenting side. New cerebral ischemic lesions were detected in 13 (39.4%) out of the 33 CAS-Bs and in 15 (39.5%) out of the 38 CAS-Fs. The mean number of total, ipsilateral and contralateral new cerebral ischemic lesion was 2.39, 1.67 and 0.73 in the CAS-B group and 2.11, 1.32 and 0.79 in the CAS-F group, respectively. No statistical differences were found between the two groups (p = 0.96, 0.74 and 0.65, respectively). The embolic complications encountered included two retinal infarctions and one hemiparesis in the CAS-B group (9.09%), and one retinal infarction, one hemiparesis and one ataxia in the CAS-F group (7.89%). There was a similar incidence of embolic complications in the two groups (p 1.00). The type of distal protection device used such as a balloon and filter does not affect the incidence of cerebral embolization after protected CAS.

Study on Friction and Wear Characteristics of Aluminum Alloy Hydraulic Valve Body and Its Antiwear Mechanism

Directory of Open Access Journals (Sweden)

Rong Li

2017-03-01

Full Text Available In order for the working status of the aluminum alloyed hydraulic valve body to be controlled in actual conditions, a new friction and wear design device was designed for the cast iron and aluminum alloyed valve bodies comparison under the same conditions. The results displayed that: (1 The oil leakage of the aluminum alloyed hydraulic valve body was higher than the corresponding oil leakage of the iron body during the initial running stage. Besides during a later running stage, the oil leakage of the aluminum alloyed body was lower than corresponding oil leakage of the iron body; (2 The actual oil leakage of different materials consisted of two parts: the foundation leakage that was the leakage of the valve without wear and wear leakage that was caused by the worn valve body; (3 The aluminum alloyed valve could rely on the dust filling furrow and melting mechanism that led the body surface to retain dynamic balance, resulting in the valve leakage preservation at a low level. The aluminum alloy modified valve body can meet the requirements of hydraulic leakage under pressure, possibly constituting this alloy suitable for hydraulic valve body manufacturing.

Personal Flotation Devices Research. Volume 2. Research Report.

Science.gov (United States)

1978-01-01

approval if it was not designed to the Type I, I , I , or IV criteria. This approach allows high life-saving effectiveness devices to enter the market if...Type X devices enjoy a market reception on the order of the reception given to Type III (the costs for Type Xs and Type Ills would be similar), an...addition to attempts to document the rate of wear of PFDs , previous researc h has measured various design features of PFDs and boater ’s attitudes . The

Dosimetric evaluation of indigenously developed non-lead bilayered radiation protective aprons

International Nuclear Information System (INIS)

Senthilkumar, S.

2018-01-01

Radiation shielding garments are commonly used to protect medical patients and radiation workers from X-radiation exposure during diagnostic imaging in hospitals. Originally, protective aprons consisted of lead-impregnated vinyl with a shielding equivalent given in millimeters of lead. All contained up to 2 mm of lead. While lead has long been used to shield patients from X-rays, its toxicity poses a health threat if the protective apron containing the metal wear out or the lead gets damaged. However, lead garments must be treated as hazardous waste for disposal and are heavy, causing back strain and other orthopedic problems for those who must wear them for long periods of time. The main purpose of this work was to indigenously develop light weight non lead based bilayered radiation protective aprons and evaluate dosimetrically with different combination of fabricated non lead materials and commercially available lead based aprons

[Patients' reaction to pharmacists wearing a mask during their consultations].

Science.gov (United States)

Tamura, Eri; Kishimoto, Keiko; Fukushima, Noriko

2013-01-01

  This study sought to determine the effect of pharmacists wearing a mask on the consultation intention of patients who do not have a trusting relationship with the pharmacists. We conducted a questionnaire survey of customers at a Tokyo drugstore in August 2012. Subjects answered a questionnaire after watching two medical teaching videos, one in which the pharmacist was wearing a mask and the other in which the pharmacist was not wearing a mask. Data analysis was performed using a paired t-test and multiple logistic regression. The paired t-test revealed a significant difference in 'Maintenance Problem' between the two pharmacist situations. After excluding factors not associated with wearing a mask, multiple logistic regression analysis identified three independent variables with a significant effect on participants not wanting to consult with a pharmacist wearing a mask. Positive factors were 'active-inactive' and 'frequency mask use', a negative factor was 'age'. Our study has shown that pharmacists wearing a mask may be a factor that prevents patients from consulting with pharmacist. Those patients whose intention to consult might be affected by the pharmacists wearing a mask tended to be younger, to have no habit of wearing masks preventively themselves, and to form a negative opinion of such pharmacists. Therefore, it was estimated that pharmacists who wear masks need to provide medical education by asking questions more positively than when they do not wear a mask in order to prevent the patient worrying about oneself.

Wear of PEEK-OPTIMA® and PEEK-OPTIMA®-Wear Performance articulating against highly cross-linked polyethylene.

Science.gov (United States)

East, Rebecca H; Briscoe, Adam; Unsworth, Anthony

2015-03-01

The idea of all polymer artificial joints, particularly for the knee and finger, has been raised several times in the past 20 years. This is partly because of weight but also to reduce stress shielding in the bone when stiffer materials such as metals or ceramics are used. With this in mind, pin-on-plate studies of various polyetheretherketone preparations against highly cross-linked polyethylene were conducted to investigate the possibility of using such a combination in the design of a new generation of artificial joints. PEEK-OPTIMA(®) (no fibre) against highly cross-linked polyethylene gave very low wear factors of 0.0384 × 10(-6) mm(3)/N m for the polyetheretherketone pins and -0.025 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates. The carbon-fibre-reinforced polyetheretherketone (PEEK-OPTIMA(®)-Wear Performance) also produced very low wear rates in the polyetheretherketone pins but produced very high wear in the highly cross-linked polyethylene, as might have been predicted since the carbon fibres are quite abrasive. When the fibres were predominantly tangential to the sliding plane, the mean wear factor was 0.052 × 10(-6) mm(3)/N m for the pins and 49.3 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates; a half of that when the fibres ran axially in the pins (0.138 × 10(-6) mm(3)/N m for the pins and 97.5 × 10(-6) mm/ N m for the cross-linked polyethylene plates). PEEK-OPTIMA(®) against highly cross-linked polyethylene merits further investigation. © IMechE 2015.

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. Copyright 2016, SLACK Incorporated.

Fractal characteristic in the wearing of cutting tool

Science.gov (United States)

Mei, Anhua; Wang, Jinghui

1995-11-01

This paper studies the cutting tool wear with fractal geometry. The wearing image of the flank has been collected by machine vision which consists of CCD camera and personal computer. After being processed by means of preserving smoothing, binary making and edge extracting, the clear boundary enclosing the worn area has been obtained. The fractal dimension of the worn surface is calculated by the methods called `Slit Island' and `Profile'. The experiments and calciating give the conclusion that the worn surface is enclosed by a irregular boundary curve with some fractal dimension and characteristics of self-similarity. Furthermore, the relation between the cutting velocity and the fractal dimension of the worn region has been submitted. This paper presents a series of methods for processing and analyzing the fractal information in the blank wear, which can be applied to research the projective relation between the fractal structure and the wear state, and establish the fractal model of the cutting tool wear.

Old stones' song: use-wear experiments and analysis of the Oldowan quartz and quartzite assemblage from Kanjera South (Kenya).

Science.gov (United States)

Lemorini, Cristina; Plummer, Thomas W; Braun, David R; Crittenden, Alyssa N; Ditchfield, Peter W; Bishop, Laura C; Hertel, Fritz; Oliver, James S; Marlowe, Frank W; Schoeninger, Margaret J; Potts, Richard

2014-07-01

Evidence of Oldowan tools by ∼2.6 million years ago (Ma) may signal a major adaptive shift in hominin evolution. While tool-dependent butchery of large mammals was important by at least 2.0 Ma, the use of artifacts for tasks other than faunal processing has been difficult to diagnose. Here we report on use-wear analysis of ∼2.0 Ma quartz and quartzite artifacts from Kanjera South, Kenya. A use-wear framework that links processing of specific materials and tool motions to their resultant use-wear patterns was developed. A blind test was then carried out to assess and improve the efficacy of this experimental use-wear framework, which was then applied to the analysis of 62 Oldowan artifacts from Kanjera South. Use-wear on a total of 23 artifact edges was attributed to the processing of specific materials. Use-wear on seven edges (30%) was attributed to animal tissue processing, corroborating zooarchaeological evidence for butchery at the site. Use-wear on 16 edges (70%) was attributed to the processing of plant tissues, including wood, grit-covered plant tissues that we interpret as underground storage organs (USOs), and stems of grass or sedges. These results expand our knowledge of the suite of behaviours carried out in the vicinity of Kanjera South to include the processing of materials that would be 'invisible' using standard archaeological methods. Wood cutting and scraping may represent the production and/or maintenance of wooden tools. Use-wear related to USO processing extends the archaeological evidence for hominin acquisition and consumption of this resource by over 1.5 Ma. Cutting of grasses, sedges or reeds may be related to a subsistence task (e.g., grass seed harvesting, cutting out papyrus culm for consumption) and/or a non-subsistence related task (e.g., production of 'twine,' simple carrying devices, or bedding). These results highlight the adaptive significance of lithic technology for hominins at Kanjera. Copyright © 2014 Elsevier Ltd. All

Flaw detection device for plasma facing wall in thermonuclear device

International Nuclear Information System (INIS)

Doi, Akira.

1996-01-01

The present invention concerns plasma facing walls of a thermonuclear device and provides a device for detecting a thickness of amour tiles accurately and efficiently with no manual operation. Namely, the position of the plasma facing surface of the amour tile is measured using a structure to which the amour tiles are to be disposed as a reference. Also in a case of disposing new armor tiles, the position of the plasma facing surface of the armor tiles is measured to thereby measure the wearing amount of the amour tiles based on the difference between the reference and the measured value. If a measuring means capable of measuring a plurality of amour tiles at once is used efficiency of the measurement and the detection can be enhanced. Several ten thousands of amour tiles are disposed to the plasma facing wall in a large scaled thermonuclear device, and a plenty of time was required for the detection. However, the present invention can improve the accuracy for the measurement and detection and provide time and labors-saving. (I.S.)

Attenuation of blast pressure behind ballistic protective vests.

Science.gov (United States)

Wood, Garrett W; Panzer, Matthew B; Shridharani, Jay K; Matthews, Kyle A; Capehart, Bruce P; Myers, Barry S; Bass, Cameron R

2013-02-01

Clinical studies increasingly report brain injury and not pulmonary injury following blast exposures, despite the increased frequency of exposure to explosive devices. The goal of this study was to determine the effect of personal body armour use on the potential for primary blast injury and to determine the risk of brain and pulmonary injury following a blast and its impact on the clinical care of patients with a history of blast exposure. A shock tube was used to generate blast overpressures on soft ballistic protective vests (NIJ Level-2) and hard protective vests (NIJ Level-4) while overpressure was recorded behind the vest. Both types of vest were found to significantly decrease pulmonary injury risk following a blast for a wide range of conditions. At the highest tested blast overpressure, the soft vest decreased the behind armour overpressure by a factor of 14.2, and the hard vest decreased behind armour overpressure by a factor of 56.8. Addition of body armour increased the 50th percentile pulmonary death tolerance of both vests to higher levels than the 50th percentile for brain injury. These results suggest that ballistic protective body armour vests, especially hard body armour plates, provide substantial chest protection in primary blasts and explain the increased frequency of head injuries, without the presence of pulmonary injuries, in protected subjects reporting a history of blast exposure. These results suggest increased clinical suspicion for mild to severe brain injury is warranted in persons wearing body armour exposed to a blast with or without pulmonary injury.

Wear behavior of 2-1/4 Cr-1Mo tubing against alloy 718 tube-support material in sodium-cooled steam generators

International Nuclear Information System (INIS)

Wilson, W.L.

1983-05-01

A series of prototypic steam generator 2-1/4 Cr-1 Mo tube/alloy 718 tube support plate wear tests were conducted in direct support of the Westinghouse Nuclear Components Division -- Breeder Reactor Components Project Large Scale steam Generator design. The initial objective was to verify the acceptable wear behavior of softer, ''over-aged'' alloy 718 support plate material. For all interfaces under all test conditions, resultant wear damage was adhesive in nature with varying amounts of 2-1/4 Cr-1 Mo tube material being adhesively transferred to the alloy 718 tube supports. Maximum tube wear depths exceeded the initially established design allowable limit of 127 μm (.005 in.) at 17 of the 18 interfaces tested. A decrease in contact stresses produced acceptable tube wear depths below a readjusted maximum design allowable value of 381 μm (.015 in.). Additional conservatisms associated with the simulation of a 40-year lifetime of rubbing in a one-week laboratory test provided further confidence that the 381 μm maximum tube wear allowance would not be exceeded in service. Softer, ''over-aged'' alloy 718 material was found to produce slightly less wear damage on 2-1/4 Cr-1 Mo tubing than fully age hardened material. Also, air formed oxide films on the alloy 718 reduced initial tube wear and delayed the onset of adhesive surface damage. However, at high surface stress levels, these films were not sufficiently stable to provide adequate long term protection from adhesive wear. The results of the present work and those of previous test programs suggest that the successful in-sodium tribological performance of 2-1/4 Cr-1 Mo/alloy 718 rubbing couples is dependent upon the presence of lubricative surface films, such as oxides and/or surface reaction or deposition products. 11 refs., 13 figs., 4 tabs

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

Wear properties of metal ion implanted 4140 steel

Energy Technology Data Exchange (ETDEWEB)

Evans, P.J. (Applications of Nuclear Physics, Ansto, Private Mail Bag 1, Menai, NSW 2234 (Australia)); Paoloni, F.J. (Department of Electrical and Computer Engineering, University of Wollongong, GPO Box 1144, Wollongong, NSW 2500 (Australia))

1994-07-01

AISI type 4140 (high tensile) steel has been implanted with tungsten and titanium using a metal vapour vacuum arc ion source. Doses in the range (1-5)x10[sup 16]ionscm[sup -2] were implanted to a depth of approximately 30nm. The relative wear resistance between non-implanted and implanted specimens has been estimated using pin-on-disc and abrasive wear tests. Implantation of titanium decreased the area of wear tracks by a factor of 5 over unimplanted steel. In some cases the steel was also hardened by a liquid carburization treatment before implantation. Abrasion tests revealed a further improvement in wear resistance on this material following ion irradiation. ((orig.))

User experiences of wearable activity monitor among 3-6-year-old preschool children – Are children willing to wear monitor 7 days 24 hours per day?

Directory of Open Access Journals (Sweden)

Suvi Määttä

2015-10-01

This study was conducted as a part of long-term DAGIS project that aims to improve the health behaviors and diminish socioeconomic inequalities in health behaviors among preschool children in Finland. A large cross-sectional survey is conducted in autumn 2015. Children (N=800, aged 3-6 years wear Actigraph WGT3X-BT accelerometer for seven days, 24 hours per day. Simultaneously with accelerometer use, parents fill in diary with informing the user experiences of accelerometer and possible non-wearing times. Parents are advised that the child wears accelerometer 24 hours and remove the belt only when in water (e.g. in shower. The accelerometer data are checked straight after data collection. Choi (2011 wear time analyses are conducted for data. The device acceptability, compliance for wearing times and reported barriers for using accelerometer 24 hours in seven days among 3-6-year-old children are reported. Conclusions This study provides new information about the usability of wearable activity monitors among 3-6-year-old children, an age group that is less studied.

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.

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.

Protective coatings for in-vessel fusion devices

International Nuclear Information System (INIS)

Brossa, F.

1984-01-01

Coatings of Al/Si, SAP (Sintered Aluminium Powder), Al 2 O 3 , TiC (low-Z material) and Ta have been developed for in-vessel component protection. Anodic oxidation, vapor depositions, reactive sputtering, chemical vapor deposition (CVD) and plasma spray have been the coating formation methods studied. AISI 316, 310, 304, Inconel 600 and Mo were adopted as base materials. the coatings were characterized in terms of composition, structure and connection with the supporting material. The behavior of coatings under H + , D + and He + irradiation in the energy range 100 eV-8 keV was tested and compared to the solid massive samples. TiC and Ta coatings were tested with thermal shock under power density pulses of 1 kW/cm 2 generated by an electron beam gun. Temperature-dependence of the erosion of TiC by vacuum arcs in a magnetic field was also studied. TiC coatings have low sputtering values, good resistance to arcing and a high chemical stability. TiC and Ta, CVD and plasma spray coatings are thermal-shock resistant. High thermal loads produce cracks but no spalling. Destruction occurred only after melting of the base material. The plasma spray coating method seems to be most appropriate for developing remote handling applications in fusion devices. (orig.)

Nitrogen implantation of steels: A treatment which can initiate sustained oxidative wear

International Nuclear Information System (INIS)

Hale, E.B.; Reinbold, R.; Missouri Univ., Rolla; Kohser, R.A.

1987-01-01

Falex wear tests on mild (SAE 3135) steel samples treated by either nitrogen implantation (2.5x10 17 N 2 + cm -2 at 180 keV) or low temperature (about 315 0 C) oxidation are reported. The results show that both treatments lead to about an order-of-magnitude reduction in the long-term wear rate of the steel. In addition to the wear rate measurements, the wear member asymmetry behavior, scanning electron microscopy studies, Auger spectra and sputter profiles all indicate that the wear modes induced by both treatments are the same and are oxidative wear. These results confirm the previously proposed initiator-sustainer wear model in which implanted nitrogen simply acts as an initiator of favorable oxidative wear but is not directly involved in maintaining the sustained wear resistance. Possible mechanisms for both the initiation process and the sustained wear process are reviewed and discussed. (orig.)

Wear behavior of tetragonal zirconia polycrystal versus titanium and titanium alloy

International Nuclear Information System (INIS)

Kanbara, Tsunemichi; Yajima, Yasutomo; Yoshinari, Masao

2011-01-01

The aim of this study was to clarify the influence of tetragonal zirconia polycrystal (TZP) on the two-body wear behavior of titanium (Ti). Two-body wear tests were performed using TZP, two grades of cp-Ti or Ti alloy in distilled water, and the cross-sectional area of worn surfaces was measured to evaluate the wear behavior. In addition, the surface hardness and coefficient of friction were determined and an electron probe microanalysis performed to investigate the underlying mechanism of wear. The hardness of TZP was much greater than that of Ti. The coefficient of friction between Ti and Ti showed a higher value than the Ti/TZP combination. Ti was more susceptible to wear by both TZP and Ti than TZP, indicating that the mechanism of wear between TZP and Ti was abrasive wear, whereas that between Ti and Ti was adhesive wear. No remarkable difference in the amount of wear in Ti was observed between TZP and Ti as the opposite material, despite the hardness value of Ti being much smaller than that of TZP. (communication)

Wear-Out Sensitivity Analysis Project Abstract

Science.gov (United States)

Harris, Adam

2015-01-01

During the course of the Summer 2015 internship session, I worked in the Reliability and Maintainability group of the ISS Safety and Mission Assurance department. My project was a statistical analysis of how sensitive ORU's (Orbital Replacement Units) are to a reliability parameter called the wear-out characteristic. The intended goal of this was to determine a worst case scenario of how many spares would be needed if multiple systems started exhibiting wear-out characteristics simultaneously. The goal was also to determine which parts would be most likely to do so. In order to do this, my duties were to take historical data of operational times and failure times of these ORU's and use them to build predictive models of failure using probability distribution functions, mainly the Weibull distribution. Then, I ran Monte Carlo Simulations to see how an entire population of these components would perform. From here, my final duty was to vary the wear-out characteristic from the intrinsic value, to extremely high wear-out values and determine how much the probability of sufficiency of the population would shift. This was done for around 30 different ORU populations on board the ISS.

Minimization of PWR reactor control rods wear

International Nuclear Information System (INIS)

Ponzoni Filho, Pedro; Moura Angelkorte, Gunther de

1995-01-01

The Rod Cluster Control Assemblies (RCCA's) of Pressurized Water Reactors (PWR's) have experienced a continuously wall cladding wear when Reactor Coolant Pumps (RCP's) are running. Fretting wear is a result of vibrational contact between RCCA rodlets and the guide cards which provide lateral support for the rodlets when RCCA's are withdrawn from the core. A procedure is developed to minimize the rodlets wear, by the shuffling and axial reposition of RCCA's every operating cycle. These shuffling and repositions are based on measurement of the rodlet cladding thickness of all RCCA's. (author). 3 refs, 2 figs, 2 tabs

Measurement and Evaluation of Wear Frogs Switches ŽSR

Directory of Open Access Journals (Sweden)

Urda Ján

2014-05-01

Full Text Available This paper deals with the measurement and evaluation of wear frogs switches ZSR. One of the main problems is the oversize wear. The possibilities analysis of this problem is offered through a set of switches and monitoring of selected parameters. One of these parameters is also monitoring the vertical wear

Wear resistance and structural changes in nitrogen-containing high-chromium martensitic steels under conditions of abrasive wear and sliding friction

International Nuclear Information System (INIS)

Makarov, A.V.; Korshunov, L.G.; Schastlivtsev, V.M.; Chernenko, N.L.

1998-01-01

Martensitic nitrogen-containing steels Kh17N2A0.14, Kh13A0.14, Kh14G4A0.22 as well as steel 20Kh13 were studied for their wear resistance under conditions of friction and abrasion. Metallography, X ray diffraction analysis and electron microscopy were used to investigate the structural changes taking place in a thin surface layer on wearing. It is shown that an increase of nitrogen content of 0.14 to 0.22% promotes an enhancement of steel resistance to abrasive and adhesive wear, especially after tempering in the range of 500-550 deg C. Typically, the nitrogen-containing steels exhibit lower resistance to various types of wear in comparison with the steels with high-carbon martensite due to their lower deformability under conditions of friction loading

Effect of pressing temperature on the wear resistance of a Co-based Cr-Mo powder alloy produced by hot pressing

Energy Technology Data Exchange (ETDEWEB)

Somunkiran, Ilyas [Firat Univ., Elazig (Turkey). Metallurgical and Materials Engineering Dept.; Balin, Ahmet [Siirt Univ. (Turkey). Dept. of Vocational High School

2016-02-01

In this study, Co-based Cr-Mo powder alloy was produced at different pressing temperatures by using hot pressing technique and abrasive wear behaviors of the produced specimens were examined. Produced specimens were exposed to abrasive wear experiment using block on disc wear test device by applying a load of 50 N with 100-mesh SiC abrasive paper. Each specimen was investigated at 25, 50, 75 and 100 m. At the end of the experiment, abrasive wear results of the specimens were determined by calculating their mass losses. Microstructural properties of the specimens which were produced at different pressing temperatures were investigated by optical and SEM examinations and their wear resistances were examined by abrasive wear experiments. Consequently, it was observed that in Co-based Cr-Mo powder alloy produced by hot pressing technique; as sintering temperature increased, size of neck formations between the powder grains increased, porosity decreased and abrasive wear resistance increased. [German] In diesem Beitrag zugrunde liegenden Studie wurde eine Co-basierte Cr-Mo-Legierung mittels Heisspressens hergestellt und der Abrasivverschleisswiderstand dieser Proben untersucht. Die hergestellten Proben wurden dem Abrasivverschleissversuch durch einen Block-Scheibe-Versuchsaufbau unterzogen, wobei eine Kraft von 50 N mit einem SiC-Papier (100 mesh) verwendet wurde. Jede Probe wurde ueber eine Distanz von 25, 50, 75 und 100 m untersucht. Am Ende der jeweiligen Experimente wurden die Abrasivverschleissergebnisse ermittelt, indem die Massenverluste berechnet wurden. Die mikrostrukturellen Eigenschaften der Proben, die bei verschiedenen Presstemperaturen hergestellt wurden, wurden mittels optischer und Rasterelektronenmikroskopie bestimmt und ihr Verschleisswiderstand anhand der Verschleissversuche ermittelt. Schliesslich wurde beobachtet, dass bei steigender Sintertemperatur der heissgespressten Co-basierten Cr-Mo-Pulverlegierung die Groesse der Einschnuerungen zwischen den

Probabilistic Analysis of Wear of Polymer Material used in Medical Implants

Directory of Open Access Journals (Sweden)

T. Goswami

2016-05-01

Full Text Available Probabilistic methods are applied to the study of fatigue wear of sliding surfaces. A variance of time to failure (to occurrence of maximum allowable wear depth is evaluated as a function of a mean wear rate of normal wear and a size of wear particles. A method of estimating probability of failure-free work during a certain time interval (reliability is presented. An effect of the bedding-in phase of wear on the reliability is taken into account. Experimental data for Ultra High Molecular Weight Polyethylene (UHMWPE cups of artificial hip implants is used to make numerical calculations.

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

Use of Protective Gloves in Nail Salons in Manhattan, New York City.

Science.gov (United States)

Basch, Corey; Yarborough, Christina; Trusty, Stephanie; Basch, Charles

2016-07-01

Nail salon owners in New York City (NYC) are required to provide their workers with gloves and it is their responsibility to maintain healthy, safe working spaces for their employees. The purpose of this study was to determine the frequency with which nail salon workers wear protective gloves. A Freedom of Information Law request was submitted to New York Department of State's Division of Licensing Services for a full list of nail salons in Manhattan, NYC. A sample population of 800 nail salons was identified and a simple random sample (without replacement) of 30% (n=240) was selected using a random number generator. Researchers visited each nail salon from October to December of 2015, posing as a potential customer to determine if nail salon workers were wearing gloves. Among the 169 salons in which one or more workers was observed providing services, a total of 562 workers were observed. For 149 salons, in which one or more worker was observed providing services, none of the workers were wearing gloves. In contrast, in six of the salons observed, in which one or more workers was providing services, all of the workers (1 in 2 sites, 2 in 1 site, 3 in 2 sites, and 4 in 1 site) were wearing gloves. Almost three-quarters of the total number of workers observed (n=415, 73.8%) were not wearing gloves. The findings of this study indicate that, despite recent media attention and legislation, the majority of nail salon workers we observed were not wearing protective gloves when providing services.