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Firing tests of a small caliber experimental gun barrel made of a cobalt-base alloy have been conducted with the purpose of determining the degree of wear and erosion due to excessive firing durations. The small amount of barrel material loss makes the cobalt-base alloy an excellent candidate for use as a gun liner. An unusual wear pattern resulting from this loss was observed near the muzzle. Elimination of chemical and thermal effects made a plausible explanation of the wear pattern possible

OBJECTIVE To analyze the wear rate of computer-aided design and computer-aided manufacturing (CAD/CAM) composites, polyetheretherketones and glass ceramics. MATERIAL AND METHODS Our study groups were prepared from two different resin-based composites (Brillant Crios, Cerasmart), a glass ceramic (IPS Emax CAD) and reinforced polyetheretherketone (BioHPP) material (n = 10). Premolar teeth were used as antagonists. The specimens, which were subjected to two body wear tests (240,000 cycles, 1.2 Hz, 50N) in the chewing simulator, were scanned with a 3D laser scanner both before and after the wear test. Volume loss and wear depth were determined by means of the obtained images software program. The wear pattern was examined by scanning electron microscopy. Kruskal Wallis test served for analyzing. RESULTS The least volume loss and wear depth were seen in the polyetheretherketone material (0.06 ± 0.04 mm3 , 0.02 ± 0.01 mm), while the maximum volume loss was seen in the groups containing resin-based composite. (p = 0.05). The volume loss value in glass ceramics is between CAD/CAM composites and polyetheretherketone. CONCLUSION The behavior of polyetheretherketone against enamel was different from glass ceramics and composite materials in terms of the amount of wear. CLINICAL SIGNIFICANCE Polyetheretheketone can be considered as an alternative to other chairside materials in terms of wear resistance.

Background and purpose — Cup wear in total hip arthroplasty (THA) can be affected by different manufacturing processes of the polyethylene (PE). We report the long-term wear pattern differences, as well as early creep behavior, between conventional PE and highly cross-linked PE (HXLPE) liners, as measured with radiostereometry (RSA) up to 10 years. We also compare migration and clinical outcome of 2 similar uncemented cups with different backside surface roughness. Patients and methods — We included 45 patients with primary osteoarthritis. 23 received a conventional liner and 22 an HXLPE liner in a similar uncemented cup, but with a slightly rougher surface. The patients were followed up with RSA and hip-specific outcome questionnaire (HOOS) at 3 months, 1, 2, 5, and 10 years. Results — During the first 3 months both liners showed expected deformation with mean proximal head penetration of 0.39 mm (conventional PE) and 0.21 mm (HXLPE). Between 3 months and 10 years there was a difference in annual wear with 0.12 mm/year for the conventional liner and 0.02 mm/year for the HXLPE liner. The cup with rougher surface had less initial migration but both types had stabilized after 3 months. The HOOS scores improved after surgery and remained high for both groups throughout the study period. Interpretation — Up to 10 years the HXLPE has consistent lower annual wear, possibly contributing to longer survival of the THA, compared with conventional PE. All patients reported good results regardless of liner type.

The cyclic utilization of coated cemented carbide inserts for turning of Inconel 718 was presented, which could be described as that the worn inserts should be given priority to repair rather than to reclaim the resources of W and Co. The assessment of the cyclic utilization was based on the fuzzy matter element (FME) according to the cutting performance including productivity, tool life, cutting forces, surface roughness, and wear mechanisms. From the productivity view accompanied with a rational tool life, the recommended cutting speed for coated cemented carbide and welding PCBN tools should be lower than 55 m/min and 92 m/min, respectively. With the cutting speed increasing, the amount of material removal of coated cemented carbide tools corresponding to the wear criterion of VB = 0.3 mm changed from 35 to 16.5 cm3, while that of welding PCBN tools varied from 25.5 to 18.6 cm3. Higher machining speed with the chamfered cutting edge for the welding PCBN tools enhanced the workpiece softening accompanied with better heat resistance, acquiring lower cutting force and better surface roughness. The dominant wear mechanisms of coated cemented carbide tools were notch wear under the lower cutting speed, while the adhesive wear became the leading factor when the speed was above 50 m/min. The welding PCBN tools showed severe wear pattern with adhesion, notching, and chipping. Based on the FME, the assessment of cutting performance demonstrated that the welding PCBN tools were better, which proved that the cyclic utilization was meaningful and improved the utilization efficiency of the worn cemented carbide inserts.

The paper discusses the influence of the thickness of nanolayers in a wear-resistant layer of the Ti-TiN-(Ti,Cr,Al)N multilayered composite coating on the coating and tool cutting properties in turning 1045 steel. The coatings with nanolayer thickness in the range of 10–302 nm were investigated. The studies showed that with a decrease in the nanolayer thickness, the cutting tool life increased. The tests revealed an optimal nanolayer thickness with regard to the tool life under the given cutting conditions, and it was 16 nm. With a further decrease in the nanolayer thickness to 10 nm, the tool life reduced.

Usually, constant process parameters are used for turning. These process parameters result in a thermomechanical load of the tool, which leads to a specific wear pattern. Varying the process parameters along the toolpath, e.g. linear or sinusoidal, can extend tool life by distributing wear over a wider area and reducing the thermal tool load. In this paper, a method for designing process parameter variations during turning is presented. It is shown that tool wear can be reduced using process parameter variation. This reduction in wear is due to a decrease in thermal tool load. In addition, a method for designing processes with modulated process parameters is being developed.

A high-speed milling experiment on wood-plastic composites was performed using cemented carbide tools, and the resulting wear pattern was studied. The influence of the cutting parameters, the cutting speed, feed speed, and axial cutting depth on the tool wear was studied via response surface methodology, and the influence of the interaction of the cutting parameters on tool wear was analyzed. Three-dimensional surface graphs and contour plots of the tool wear results were established. According to the experimental results, a mathematical model of the tool wear based on the second-order response surface methodology was established, and the model was utilized to verify its feasibility. The results show that the nose width (NW) increases with the increase of the cutting speed and axial cutting depth and decreases with the increase of feed speed. Among the factors affecting tool wear, the cutting speed had the greatest influence, followed by the feed rate, with the axial cutting depth affecting tool wear the least. According to the results of the interaction between the tool wear and the cutting parameters, a low feed speed and small axial cutting depth can be selected to ensure long tool life; for low-speed cutting, a high feed speed and large axial cutting depth can be adopted to ensure tool life while improving machining efficiency.

Knee instability is the second most common cause of revision after total knee arthroplasty (TKA). Genu recurvatum (GR) is the rarest form of instability usually occurring in patients with underlying conditions such as neuromuscular disorders and fixed valgus deformities. The literature regarding de novo post-TKA GR and its treatment is scarce. In this case series and review of literature, we aimed to review the treatment strategies of post-TKA GR and to present our experience in the treatment of late-onset de novo GR after TKA by isolated polyethylene exchange. To our knowledge, isolated polyethylene exchange has not been so far described for GR correction after TKA. We found a unique wear pattern at the base of the liner post in all 3 patients. They showed a satisfactory outcome with no recurrence on a mean follow-up of 26.67 months.

Objectives Carabelli is a nonmetric dental trait variably expressed as a small pit to a prominent cusp in the maxillary molars of modern humans. Investigations on the occurrence and expression rates of this trait have been conducted extensively, tracing its origin to genetic sources. However, there remains a lack of understanding about its potential role in chewing. In this study, we examine molar macrowear with the aim of reconstructing Carabelli trait occlusal dynamics occurring during chewing. Methods We have examined 96 deciduous and permanent maxillary molars of children and young adults from Yuendumu, an Australian Aboriginal population that was at an early stage of transition from a nomadic and hunter-gatherer way of life to a more settled existence. We apply a well-established method, called Occlusal Fingerprint Analysis, which is a digital approach for analyzing dental macrowear allowing the reconstruction of jaw movements required to produce wear pattern specific to each tooth. Results Carabelli trait slightly enlarges the surface functional area, especially in those molars where this feature is expressed in its cuspal form and it is closer to the occlusal plane. Moreover, the highly steep contact planes would also indicate that Carabelli wear areas contribute to increasing the shearing abilities of the occluded teeth, which are particularly important when processing fibrous and tough foods. Conclusions The macrowear analysis suggests that Carabelli trait in the Aboriginal people from Yuendumu slightly enhanced occlusion and probably played some functional role during mastication. Future biomechanical and microwear analyses could provide additional information on the mechanical adaptation of Carabelli trait in modern human dentition.

This study presents the results of detailed wear process examination on polyformaldehyde gears under both dry and lubricated conditions. A multi-purpose durability test rig was employed to study the wear performance of polyformaldehyde gear pairs. The wear behaviors of polyformaldehyde gears under dry and oil-lubricated operating conditions were characterized via measurements of gear tooth surface micro-topography and tooth profile deviation. Under the dry running condition, a hump and a gully appear on the tooth surface in the pitch line area of the driving gear and the driven wheel, respectively. The largest amount of wear was observed around the tooth root of the driving gear. However, the gear tooth wear pattern with lubrication is different from that under the dry running condition.

This study investigated the friction and wear pattern of silica-reinforced Styrene-Butadiene Rubber (SBR) in sliding friction with a steel blade indenter. The experiments were conducted using a pin-on-disc tribometer at various applied loads and examined under dry and wet contact conditions. Analysis was focused on investigating the coefficient of friction and length of wear pattern spacing. Related to coefficient of friction identification, the abrasion theory was applied here. In addition, the stick-slip theory to identify the wear pattern spacing was also applied. Results of the experiments show that the overall coefficient of friction (COF) decreases along with the increasing applied loads. The COF in wet conditions is much lower at the beginning of sliding time than the COF in dry conditions. The wear pattern spacing increases with increasing loads. However, it seems that there is no significant difference in pattern spacing between the dry and wet contact condition. In general, the experimental results agree qualitatively with the analytical results.

Context: Edentulous patients often complain about the instability of mandibular denture. To overcome that, implant-supported overdentures (IODs) have been applied as a good prosthetic option. Aims: The current study compared the changes in retentive force and patterns of surface wear of nylon rings of two stud attachments (ball and locator) upon cyclic loading. Subjects and Methods: Two implant analogs were fixed parallel to each other, 22 mm apart, in custom-made rectangular blocks for each attachment system. Ten nylon inserts of each attachment system were tested. Universal testing machine was used to measure the retentive force, and a low-value fatigue testing machine was used for cyclic loading of 2500 insertion–removal cycles. Surface changes of the components were evaluated by scanning electron microscope (SEM). Statistical Analysis Used: Paired Student's t-test was used to determine groups that were statistically significant. Results: The greatest retention loss rate, i.e., the difference between the initial retentive force and final retentive force was observed in the ball attachment (6.20 N) followed by locator attachment (3.70 N). The results were found to be statistically significant (d ≤ 0.001**). Upon SEM analysis, the nylon inserts of ball attachment revealed more surface wear compared to that of locator attachment. Conclusions: For greater retention and longer function, locator overdenture attachment should be preferred for implant overdentures over ball attachment.

Elastomeric materials are used in daily applications, such as tires and conveyor belts. Sliding friction of elastomeric materials often produces a unique periodic wear pattern. In general, the periodic wear pattern has to be prevented because it generates surface instabilities and, as a result, vibration. Sliding contact between an elastomer and a rigid ball may cause the development of a periodic wear pattern like a wave on the elastomer surface, called a wavy wear track. The present study has investigated the occurrence of the wavy wear track on the elastomers under several operating conditions. The elastomers used were a Styrene-Butadiene Rubber (SBR) and Butadiene Rubber (BR) reinforced with two types of fillers, i.e., highly dispersible silica and short-cut aramid fiber. A pin-on-disc tribometer was used to study the wavy wear track of the materials under several operating conditions. An analytical model was used to predict the wave length of the wear pattern and to study the occurrence of the wavy wear track. The results show that the occurrence of the wavy wear track depends on the mechanical properties of the elastomer, the operating conditions (such as sliding velocity and force), the inertia mass of the counter surface frame and the circumferential length of the wear track. The analytical model is in good agreement with the experimental results.

In the mining industry, slips and falls are the second leading cause of non-fatal injuries. Footwear is the primary defence against a slip; consequently, the condition of the footwear outsole is critical to maintaining slip resistance. Currently, there is no published method that can be used to determine when the outsole no longer affords adequate slip protection. Moreover, quantifying the condition of the outsole through the measurement of outsole features can be tedious. This article introduces a new method for the quantification of boot outsole wear. Using a handheld 3D scanner, boot scans can be taken quickly and the developed models used to measure outsole features. This method also accounts for the bending of the boot due to normal wear, which may otherwise introduce erroneous measures. When compared to measurements with a traditional handheld calliper, this new method offers more flexibility in terms of data collection, accounts for other types of boot transformations, and is more efficient to use over multiple measurement periods with no statistically significant differences in measurement.

Experiments involving machining of Fe-50%-Al Mechanical Alloy specimen are conducted at different values of machining parameters using coated carbide tool inserts. Flank wear is measured at regular intervals to establish wear pattern. Output parameters such as tool life, production cost and production rate are analyzed for optimum values of speed and feed. It is established that usage of optimum values would result in increase of tool life and production rate and reduction in the production cost.

© 2017 Journal of Shoulder and Elbow Surgery Board of Trustees Background The type B3 glenoid is an addition to the Walch classification. A potential etiologic theory is that it is a progression of the B2. It is characterized by uniconcavity, absent paleoglenoid, medialization, retroversion, and subluxation. The purpose of this study was to describe the morphology of B3 glenoids. Methods Fifty-two patients with B3 glenoids underwent 3-dimensional analysis of computed tomography data. Glenoid measurements (retroversion, inclination, medialization) and humeral head subluxation according to the scapular and glenoid planes were determined. The measured variables were compared between male and female patients. Results The mean B3 retroversion, inclination, and medialization were 24° ± 7°, 8° ± 6° superior, and 14 ± 4 mm, respectively. The mean posterior subluxation was 80% ± 8% and 54% ± 6% according to the scapular and glenoid planes, respectively. There were no differences in B3 characteristics between sexes (P > .05). A significant correlation existed between glenoid retroversion and humeral head subluxation relative to the scapular plane, with every 1° increase in retroversion translating to a 1% increase in subluxation (P

Teeth of iguanodontian ornithopods and ceratopsians could be remarkably similar, thus the referral of isolated dental material to particular neornithischian clades can be highly problematic. These groups are represented by the rhabdodontid Mochlodon vorosi and the basal coronosaurian Ajkaceratops kozmai in the Upper Cretaceous Csehbanya Formation at Iharkut (western Hungary). Whereas teeth of Mochlodon are common elements at the locality, no dental material belonging to Ajkaceratops was identified until now. Here we used mathematical statistical approaches, as well as tooth wear and dental microstructure analysis in order to decide whether the teeth previously referred to Mochlodon can be treated as a homogenous sample, or some remains belong rather to Ajkaceratops. According to our results, there was a striking morphological and structural convergence between the teeth of both taxa. However, the wear study revealed the existence of two different patterns within the sample. One is characterized by straight and parallel microstriations that suggest orthal movements during the jaw closure. This pattern was associated with Mochlodon. The other pattern appeared only on a few teeth, and it can be differentiated by its distinctive curved microstriations that indicate circumpalinal chewing. Because curved striations have never been described in ornithopods, but are found in several neoceratopsians, this pattern was associated here with Ajkaceratops. Here we present the first teeth that can provisionally be referred to the latter genus. We believe that the methodology discussed in this article will facilitate distinguishing ceratopsian and ornithopod teeth in other localities as well. Anat Rec, 300:1439-1463, 2017. © 2017 Wiley Periodicals, Inc.

Ultrasonic welding has been used for joining lithium-ion battery cells in electric vehicle manufacturing. The geometric profile change of tool shape significantly affects the weld quality and should be monitored during production. In this paper, a high-order decomposition method is suggested for tool wear monitoring. In the proposed monitoring scheme, a low dimensional set of monitoring features is extracted from the high dimensional tool profile measurement data for detecting tool wear at an early stage. Furthermore, the proposed method can be effectively used to analyze the data cross-correlation structure in order to help identify the unusual wear pattern and find the associated assignable cause. The effectiveness of the proposed monitoring method was demonstrated using a simulation and a real-world case study.

Experimental correlation between varying processing and wear behaviour of ternary Ni-Co-SiO2 composites coating was investigated. The parameter used in this research are: SiO2 (5–25 wt%), thermal treatment (100–300 °C), applied load (5–15 N). The results show that novel ternary Ni-Co-SiO2 nanoparticle composite coating was successful applied to mild steel. The addition SiO2 nanoparticles in the coating Ni-Co bath lead to uniform microstructure. Thermal treatment of the coating at 300 °C decreased wear rate by (−0.031), increasing the wt% of SiO2 from 0 to 25 decreased the wear rate by −0.018, applied load increases from 5 to 15 N raises the wear rate raises (0.0097), The lower wear rate was obtained at 25 wt% SiO2, applied load 5 N and thermal treatment at 300 °C. Validation of the results from pin on disc test with electro-hydraulic servo PV friction testing machine shows the same wear pattern. One can concluded in this work that the wear rate of the coated materials depend on the made up of the coating and not on the type of wear mechanism. It have be established in this work that thermal treatment and SiO2 nanoparticle can be used to enhance the wear behaviour of Ni-Co coating of mild steel.

Rail corrugation, a widely distributed periodic wear pattern of the railway track, is a severe rail defect that could cause high-pitched noises and vibrations of the ground and nearby buildings. The current rail corrugation inspection trolley can only be employed offline, whereas online monitoring devices require external batteries that depend heavily on manual maintenance. This paper presents a novel approach by monitoring the rail corrugation online using a self-contained energy harvesting system. The mechanics of the magnetic-floating energy harvester was improved by a triple-magnet configuration, and differences between repellent and attractive configurations were investigated. Comprehensive broad-band (5–2000 Hz) sinusoidal sweeping vibration tests and stochastic vibration tests were conducted based on the measured railway track spectra. The wavelet theory was used to carry out time–frequency analysis and identify the defects of the rail corrugation. The results indicate that the proposed system could collect the rail vibration energy across a wider frequency range as well as identify the rail corrugation by the induced voltage of the energy harvesters. This study offers a new sustainable approach toward rail corrugation monitoring by the self-contained energy harvesting system that could eliminate environmentally-unfriendly batteries and reduce manual involvement for railway track inspection.

In this article, we report a 67-year-old male patient who had a different wear pattern on the bottom of his tennis shoe after surgical repair of acute Achilles tendon rupture with 22-year follow-up. The wear pattern was well-matched with dynamic pedobarography. In left shoe with less total contact area and higher pressure values, there was more wear compared to right shoe.

Carbon fiber-reinforced plastics (CFRPs) and titanium alloys have different mechanical properties and show the unique processing characteristics in the cutting process. In order to complete hole-making of CFRP/Ti stacks with larger thickness, a comparative study was conducted on the stacks of CFRP/Ti versus CFRP and titanium alloy single plate in the helical milling process. Experimental results show that cutting performance including cutting force and tool wear pattern and hole quality in helical milling of stacks are all different to single plate. The impact of tool wear on the cutting force is relatively significant while machining of CFRP compared to titanium alloy. While machining of CFRP/Ti stacks, axial forces of titanium alloy suddenly change very larger than single titanium plate due to tool wear, and tool wear state shows combination of several wear pattern. Undersized CFRP holes and oversized Ti plate holes are produced when milling single plate; however, oversized CFRP and undersized Ti plate holes are observed when machining of stacks. The results also indicate that tool wear in helical milling of CFRP will influence the cutting performance of stacks.

The aim of this study was comparative analysis of sediment-induced erosion on optimized design and traditional design of Francis runner blade. The analysis was conducted through laboratory experiments in a test rig called Rotating Disc Apparatus. The results showed that the extent of erosion was significantly less in the optimized design when compared based on the material loss. It was observed that the optimized design could reduce sediment erosion by about 14.4% if it was used in place of the reference design for entire duration of the experiment. Based on the observations and results obtained, it has been concluded that the optimization of hydraulic design of blade profile of Francis runner can significantly reduce the effect of sediment-induced erosion.

Chewing, drinking, and occasional tooth grinding will result in physiological tooth wear during a lifetime. Extreme challenges, such as bruxism or habitual chewing on foreign objects, may lead to excessive wear. Recently, the role of erosion in accelerating mechanical tooth wear has been recognized, but the interplay between chemical and mechanical wear processes has not been extensively studied. Our laboratory recently introduced a novel oral wear simulation device, the Rub&Roll, that enables the user to perform wear and loading studies separately or simultaneously in an erosive and/or abrasive environment. This manuscript describes an application of the device: the combined mechanical and erosive loading of extracted human (pre)molars in a simulated chewing movement, with a controlled application of force, velocity, fluid, and time, and the application of non-contact profilometry in visualizing and measuring the resulting wear pattern. The occlusal morphology that was created in the experiment with the highest loading level is very similar to the clinical presentation of erosive wear.

Objectives Exact symmetry and perfect balance between opposite jaw halves, as well as between antagonistic teeth, is not frequently observed in natural masticatory systems. Research results show that asymmetry in our body, skull, and jaws is often related to genetic, epigenetic, environmental and individual ontogenetic factors. Our study aims to provide evidence for a significant link between masticatory asymmetry and occlusal contact between antagonist teeth by testing the hypothesis that tooth inclination is one of the mechanisms driving distribution of wear in masticatory phases in addition to dietary and cultural habits. Materials and Methods The present work investigates the relationship between dental macrowear patterns and tooth inclinations on a sample of complete maxillary and mandibular 3D models of dental arches from 19 young and adult Yuendumu Aboriginal individuals. The analysis was carried out on first molars (M1) from all quadrants. Occlusal Fingerprint Analysis was used for the quantification of macrowear patterns, and 2D cross‐sectional geometric analysis was carried out to investigate asymmetry in dental arches. Results The asymmetry is highly variable on both arches, and it is associated with differences in the inclination of upper M1 crowns. Each molar has variable inclination (buccal/lingual) which influence tooth to tooth contact, producing greater or lesser variation in wear pattern. Interindividual variability of morphological variation of the occlusal relationship has to be considered in macrowear analysis. Discussion Our results suggest that overall asymmetry in the masticatory apparatus in modern humans affects occlusal contact areas between antagonist teeth influencing macrowear and chewing efficiency during ontogeny.

Purpose To develop a fitness tracker (FitSight) to encourage children to increase time spent outdoors. To evaluate the wear pattern for this tracker and outdoor time pattern by estimating light illumination levels among children. Methods The development of the FitSight fitness tracker involved the designing of two components: (1) the smartwatch with custom-made FitSight watch application (app) to log the instant light illuminance levels the wearer is exposed to, and (2) a companion smartphone app that synchronizes the time outdoors recorded by the smartwatch to smartphone via Bluetooth communication. Smartwatch wear patterns and tracker-recorded daily light illuminance levels data were gathered over 7 days from 23 Singapore children (mean ± standard deviation age: 9.2 ± 1.4 years). Feedback about the tracker was obtained from 14 parents using a three-level rating scale: very poor/poor/good. Results Of the 14 parents, 93% rated the complete "FitSight fitness tracker" as good and 64% rated its wearability as good. While 61% of 23 children wore the watch on all study days (i.e., 0 nonwear days), 26% had 1 nonwear day, and 4.5% children each had 3, 4, and 5 nonwear days, respectively. On average, children spent approximately 1 hour in light levels greater than 1000 lux on weekdays and 1.3 hours on weekends (60 ± 46 vs. 79 ± 53 minutes, P = 0.19). Mean number of outdoor "spurts" (light illuminance levels >1000 lux) per day was 8 ± 3 spurts with spurt duration of 34 ± 32 minutes. Conclusion The FitSight tracker with its novel features may motivate children to increase time outdoors and play an important role in supplementing community outdoor programs to prevent myopia. Translational relevance If the developed noninvasive, wearable, smartwatch-based fitness tracker, FitSight, promotes daytime outdoor activity among children, it will be beneficial in addressing the epidemic of myopia.

LCD panels are used widely in all sorts of devices. Since glass is the main material used to make the panels, scratch resistance is an important issue in acquiring high quality LCD panels. In this work the wear behaviors of three types of commercially available LCD panel glasses were investigated. A pin-on-reciprocating tribotester was used to perform the wear tests using the glass specimens against a stainless steel ball. The hardness of the specimens was initially obtained. It was shown that the wear amount varied with respect to the applied load as well as the type of glass. The wear pattern of the glass specimen was also characterized using confocal microscopy. It is expected that the results of this work will aid in improving the tribological properties of LCD panel glass.

The effect of polyethylene oxide (PEO) inclusion in carbon nanotube (CNT) coating on the tribological properties of the composite coating was investigated. CNT/PEO composite coatings with 12 different weight fractions were fabricated by using the spin-coating method on pre-cleaned Si (1 0 0) substrates. Wear tests were performed using a reciprocating tribo-tester under an applied load of 10 mN and a speed of 4 mm/s. A 1.6 mm diameter stainless-steel ball was used as the pin and the corresponding Hertzian contact pressure was calculated to be ∼20 kPa. From the experimental results, it was shown that the steady-state friction coefficients for the CNT/PEO coatings gradually decreased from ∼0.47 to ∼0.3 as the concentration of PEO increased from 0 wt.% to 75 wt.%. The wear volume of the CNT/PEO composite coating rapidly increased with increasing amount of PEO when the weight fraction of PEO was comparatively low. The wear volume reached the maximum value for 87/13 wt.% of CNT/PEO coating and showed a continuous decrease in the wear volume with further increase in the PEO weight fraction. Morphological analyses of the wear pattern revealed that wear mechanism of the composite coating varied with respect to PEO concentration. The overall experimental results demonstrated that the tribological properties of CNT-based coatings could be significantly improved by adding an optimum amount of PEO. The reason for such an improvement was attributed to the enhancement of interfacial forces within the composite coating due to the presence of PEO.

Feeding in thyreophoran dinosaurs is poorly understood. Although the group existed for over 130 million years, only the Early Jurassic basal thyreophoran Scelidosaurus harrisonii and the Late Cretaceous ankylosaurid Euoplocephalus tutus have been studied from this perspective in detail. In contrast to the earlier, conservative hypothesis of a simple "orthal pulping" feeding mode with no or limited tooth-tooth contact, recent studies have demonstrated precise dental occlusion with differing jaw mechanisms in these two species. Here, we describe the first detailed study of feeding related characters in a nodosaurid ankylosaur, Hungarosaurus tormai, from the Late Cretaceous of Hungary. Dental wear patterns comprising small, apical, and low-angled facets on the maxillary and steep, extended, and bowl-like facets on the dentary teeth reveal sophisticated tooth-tooth contact in this basal nodosaurid. The presence of two different scratch generations (vertical and low-angled) on the dentary teeth unambiguously demonstrate a multiphasic powerstroke, which is further supported by the morphology of the quadrate-articular and mandibular symphyseal joints and by the architecture of the reconstructed jaw adductors. Chewing started with an initial slicing phase associated with orthal movement that was followed by a retractive powerstroke with significant occlusal contact. Because of the curved tooth rows, these movements were probably facilitated by some mediolateral translation and/or axial rotation of the mandibles to produce precise shearing along the whole tooth row. These results demonstrate that complex jaw mechanisms and dental occlusion were more widespread among thyreophorans than thought previously and that palinal movement was present in at least two ankylosaurian lineages.

Large-head metal-on-metal (MoM) hip arthroplasties have demonstrated poor survival. Damage at the taper-trunnion junction is a contributing factor; however, the influence of junction design is not well understood.(1) Does taper type affect fretting, corrosion, and volumetric wear at the junction? (2) Do taper types have different wear patterns? (3) Does larger offset or head diameter increase fretting, corrosion, and wear? (4) Is the extent of fretting and corrosion associated with earlier failure?Taper damage in 40 retrieved heads was subjectively graded for fretting and corrosion, and wear was determined with high-resolution confocal measurement. Taper types (11/13, 12/14, and Type 1) differed by angle, distal diameter, and contact length; Type 1 were thinnest and 11/13 had longer contact lengths.Fretting scores were higher in 11/13 than in Type 1 tapers. Volumetric wear and wear rates did not differ among types. Uniform, circumferential, and longitudinal wear patterns were observed in all types, but fretting, corrosion, and wear did not differ among the patterns. Head diameter and lateral offset did not correlate with fretting, corrosion, or wear. No correlation was found between fretting, corrosion, or wear and length of implantation.In general, thicker tapers with longer contact lengths were associated with greater fretting scores, whereas no relationship was found among the three designs for corrosion scores or volumetric wear. This finding suggests that trunnion diameter and engagement length are important factors to consider when improving taper-trunnion junction design.

Purpose – This paper presents an analysis of several issues that are preponderant for the work-wear design. The purpose of this paper is to create a prototype of a women’s base upper body garment, based on the information gathered. Design/methodology/approach – All the necessary information was collected through questionnaires, anthropometric measurements and evaluation of compression forces between the different prototypes. Findings – It was possible to conclude that to create a better design some alterations need to be made in the standard base pattern design, such as measurements across the back length. Research limitations/implications – Despite the fact that these design changes have a great impact on the stretch ability and on the compression forces, using softer fabric, such as cotton, is always better for an increased comfort. However, in more professional situation where these fabrics should not be used, these design changes can really make a difference. Practical implications – A test with a set of compression sensors showed that the simple alteration of one measurement in the design of the base patterns highly reduces the compression forces. Social implications – These simple alterations allow the garments to adjust to the users’ needs, promoting higher levels of comfort and lower levels of limitations of movement. Originality/value – The designs presented in this paper can be easily adapted to a variety of garments, such as jackets or dresses, both for leisure or professional activities., info:eu-repo/semantics/publishedVersion

In this paper, the composite material Go/CF/PTFE tribological property was studied. The test of its mechanical property, and the fabrication of the filled PTEE composite material sample which is based on the technology of cold press molding and sinter molding proved that adding Go and CF moderately to the composite material was an efficient way to improve its mechanical property. Meanwhile the process of friction and wear trial and SEM analysis results of the micro-structure of wear pattern proved that the addition of the Go and CF tremendously improved the anti-wear property and that after the addition the plowing effect which took place on the material surface would turn into a kind of mixed wear effect that includes plowing effect and fatigue wear. Working as pinning and bridging, the Go which distributing uniformly in the matrix was able to improve the resistance and substantially resisted the crack propagation, therefore to a certain degree enhanced the intensity of composite material and prolong its lifespan.

Bi-modular primary hip stems exhibit high revision rates owing to corrosion at the stem-neck taper, and are associated with local adverse tissue reactions. The aim of this study was to relate the wear patterns observed for one bi-modular design to its design-specific stem-neck taper geometry. Wear patterns and initial geometry of the taper junctions were determined for 27 retrieved bi-modular primary hip arthroplasty stems (Rejuvenate, Stryker Orthopaedics) using a tactile coordinate-measuring device. Regions of high-gradient wear patterns were additionally analyzed via optical and electron microscopy. The determined geometry of the taper junction revealed design-related engagement at its opening (angle mismatch), concentrated at the medial and lateral apexes (axes mismatch). A patch of retained topography on the proximal medial neck-piece taper apex was observed, surrounded by regions of high wear. On the patch, a deposit from the opposing female stem taper—containing Ti, Mo, Zr, and O—was observed. High stress concentrations were focused at the taper apexes owing to the specific geometry. A medial canting of the components may have augmented the inhomogeneous stress distributions in vivo . In the regions with high normal loads interfacial slip and consequently fretting was inhibited, which explains the observed pattern of wear.

The tribological properties of FKM fluorocarbon elastomer were investigated with the aim of developing suitable accelerated wear test conditions for this type of seal material. The wear pattern of the specimen under normal operating conditions was monitored over a test time of 1000 h to be used as a reference. The results were compared with experiments performed under accelerated testing conditions. It was found that by mixing alumina particles of ∼1 μm with the lubricant, the wear of a FKM specimen could be accelerated by a factor of 58, while maintaining similar wear behavior as that of the normal test conditions. The results of this work are expected to aid in the prediction of life FKM elastomer seals.

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

[EN] This paper presents a simulation tool designed for predicting the wear pattern on the running surface of the rails and for studying the evolution of rail corrugation after thousands of wheelset passages. This simulation tool implements a cyclic track model, a rotating flexible wheelset model, a wheel-rail contact model and a wear model. The vehicle-track system is modelled by using a substructuring technique, by which the vehicle, the rails and the sleepers are treated independently of each other and are coupled by the forces transmitted through the wheel-rail contact and the railpad. The vehicle model takes only account of the wheelset since the sprung masses of the vehicle are not relevant in the frequency range analysed. The wheelset model considers the flexibility of the wheelset and the effects associated with rotation. By using the Campbell diagram, two cases have been identified in which the combined effect of two different modes may give rise to higher wheel-rail contact forces and wear. © 2011 Taylor & Francis., The authors gratefully acknowledge the support for this work provided by the Project TRA2010-15669 (Ministerio de Ciencia e Innovacion) and the valuable help of P. Torstensson from Chalmers University, who suggested the use of the Campbell diagram in this investigation.

To work in the fashion industry which has entered the digital age, and in specialization and high-industrialization age, one needs to attain various skills required for the qualifications of a fashion specialist. For these, qualification certificate systems are enacted to nurture specialized technical personnel, and among these, a jacket pattern is selected from the practical examination of Western-style dress skill prepared for nurturing specialist who can design, cut, and sew women`s clothing, to be compared and analyzed against the existing printed practical textbooks, technical books of making clothes which used as college textbooks, and local documents of theoretical study documents. The methodology of the research is to select 8 samples for the study, analyze the identity with the design, and then cut applying the identical dimensions and compare the measurements, and make the clothes using each cutting methods, and inspect to find the consistency with the design and made statistical analysis. As a result, we designed and made research patterns, and suggested a jacket pattern design to patterns simply that suits the design fast.