Body Worn Research Articles

Exposure assessment and risks associated with wearing silver nanoparticle-coated textiles

Background Silver (Ag) nanoparticles (NPs) are used increasingly in consumer and healthcare fabrics due to their antimicrobial properties. Abrasive leaching experiments have shown that AgNPs can be released during textile wear and cause a dermal exposure. Derived-no-effect-limit value for AgNPs ranges from 0.01 to 0.0375 mg/kg-body-weight, and thus, low exposures levels can cause relevant risk. Methods In this study AgNP release from textiles by artificial sweat immersion and mechanical stress was investigated. A mass balance model was used to calculate dermal Ag exposure and potential intake via percutaneous absorption and inadvertent (peri-)oral intake during wear of face mask, suit with a full body exposure and gloves. Mass flow analysis was performed for up to 8-h wear time and by using Ag penetration rate constants reported for fresh-, cryopreserved- and glycerolized skin grafts. Results Dermal intake risk characterization ratio (RCR) during 8-h wear time for glycerolized skin was up to 0.02 for face mask and 0.9 for full body wear in a worst-case condition. Wearing gloves for 1-h followed by single unintentional fingertip mouthing (contact area 11.5 cm2) resulted in an RCR of 0.0002. RCR varied depending on the type of textile-product, exposure wear duration and skin type. Conclusions This study provides a comprehensive assessment of AgNPs release from textiles and their potential impact on human dermal exposure and was essential for understanding the safety implications for different exposure scenarios and mitigating potential risks.

Comparative Evaluation of Two Body Wear of PEEK vs Milled PMMA vs Indirect Composite After Chewing Simulation- An In Vitro Study

Comparative Evaluation of Two Body Wear of PEEK vs Milled PMMA vs Indirect Composite After Chewing Simulation- An In Vitro Study

Microstructural and tribological properties of cold sprayed high content SiCp/Al coating by SiCp mild-oxidation treatment

This paper presents the results of the influence of irregular SiC particles, treated by mild-oxidation at 1100 °C, on deposition behavior (deposit rate, surface finish roughness), and deposition body (microstructure, friction, and wear). Coatings are obtained using the cold-sprayed method, employing a powder mixture comprising 36 vol% irregular SiC powder treated by mild-oxidation and 64 vol% aluminum powder as feedstock. Results show that the silicon carbide particles are treated by mild-oxidation, the external surface of silicon carbide particles is predominantly composed of soft ceramic silica, and the particle edges are passivated. The results indicate that, under identical cold-sprayed process conditions, both the deposition amount of the coating and the retention amount of SiC particles increased. The particle fragmentation and particle distribution of SiC are obviously improved. The coating did not exhibit any harmful phases. Local weak metallurgical bonding is found at the interface of SiCp and Al matrix. Furthermore, the coating's porosity decreased, after SiCp mild-oxidation, the friction coefficient (0.5716) is decreased by 12.9 %, and the wear amount (0.159 mm3/N·m) is decreased by 64.7 %. A dense and uniformly distributed aluminum matrix composite coating with a high SiC particles content is achieved.

Exposure assessment and risks associated with wearing silver nanoparticle-coated textiles

Background Silver (Ag) nanoparticles (NPs) are used increasingly in consumer and healthcare fabrics due to their antimicrobial properties. Abrasive leaching experiments have shown that AgNPs can be released during textile wear and cause a dermal exposure. Derived-no-effect-limit value for AgNPs ranges from 0.01 to 0.0375 mg/kg-body-weight, and thus, low exposures levels can cause relevant risk. Methods In this study AgNP release from textiles by artificial sweat immersion and mechanical stress was investigated. A mass balance model was used to calculate dermal Ag exposure and potential intake via percutaneous absorption and inadvertent (peri-)oral intake during wear of face mask, suit with a full body exposure and gloves. Mass flow analysis was performed for up to 8-h wear time and by using Ag penetration rate constants reported for fresh-, cryopreserved- and glycerolized skin grafts. Results Dermal intake risk characterization ratio (RCR) during 8-h wear time for glycerolized skin was up to 0.02 for face mask and 0.9 for full body wear in a worst-case condition. Wearing gloves for 1-h followed by single unintentional fingertip mouthing (contact area 11.5 cm2) resulted in an RCR of 0.0002. RCR varied depending on the type of textile-product, exposure wear duration and skin type. Conclusions This study provides a comprehensive assessment of AgNPs release from textiles and their potential impact on human dermal exposure and was essential for understanding the safety implications for different exposure scenarios and mitigating potential risks.

Influence of MoS2 nano-filler additions on wear behavior of carbon fiber reinforced epoxy composites

In this research work, two body wear and three-body wear performance of carbon fabric reinforced HTR 212 epoxy resin(CF/Epoxy) composites are experimentally evaluated. Carbon fabric/epoxy resin composite panels with MoS2 nano-filler additions of 0.1, 0.2, 0.4 and 0.7 weight percentage are developed by Vacuum Assisted Resin Transfer Molding process. Two Body Wear test is conducted on the prepared specimen in accordance with ASTM G-99, whereas Three Body Abrasive wear test is conducted as per ASTM G-65. Experimental Tests are conducted for sliding and abrading distances in multiples of 250 m up to 1500 m. Results reveal that Carbon fabric/epoxy resin composites with 0.7 weight percent of MoS2 show 18% reduction in two body wear compared to a decrease of 35% in Three Body abrasive wear at 1500 m abrading distance. Scanning Electron Microscopy is used to study the surface morphology of the tested samples and to know the mode of damage at the surface.

The Induced Orientation of Hydroxypropyl Methylcellulose Coating for Ultralow Wear

This study investigated the frictional properties of HPMC under different load and concentration conditions through friction experiments and surface characterization. The study aimed to explore and reveal the influence of load and concentration on the frictional properties of HPMC, as well as its anti−wear mechanism. The results of the study indicated that under the same solution concentration, the effect of load on the friction coefficient of HPMC was not significant. Specifically, for samples with low concentration (C−0.2), the wear ratio of HPMC under a 4 N load (1.01 × 10−11 mm3·N−1·m−1) was significantly lower than the wear ratio under a 2 N load (1.71 × 10−10 mm3·N−1·m−1). The orientation−driven formation of graphite−like carbon nanosheets, initiated by the decomposition of HPMC short chains, created a tribofilm−containing organic−chain mixed nanosheet on the sliding contact surface, which prevented direct contact between the upper and lower friction pairs. This achieved the anti−wear mechanism of two−body wear (tribo−film of an mDLC−coated ball and tribo−film of a GLC−coated Si wafer), ultimately leading to a state of ultra−low wear at the interface. The excellent anti−wear performance of HPMC suggests its potential as a candidate for the next generation of environmentally friendly bio−based solid lubricants.

Comparison of Two Body Wear Resistance of Novel Strength- Gradient Monolithic Zirconia with Two Different CAD/CAM Materials

Objective: Novel strength-gradient monolithic zirconia is a developed material recently introduced to the market and its mechanical properties should be investigated in vitro. The aim of the study is to compare the wear rates of three different CAD/CAM materials with a chewing simulator after one year of dynamic loading.
 Methods: 7x7x3 mm discs were prepared from lithium disilicate, strength-gradient monolithic zirconia, and zirconia-reinforced lithium silicate glass ceramic. Both groups were divided into two subgroups (n=12) as glazed and mechanically polished. 
 The samples were scanned with a laser scanner device (SD Mechatronic Laser Scanner LAS-20, Westerham, Germany) to determine the amount of wear. The samples were placed in a chewing simulator (SD Mechatronic Chewing Simulator CS-4.2, Westerham, Germany) for 240 000 cycles which is equivalent to 1 year of clinical use. After the dynamic loading in the chewing simulator, the samples were scanned again in the laser scanner, and the data was obtained. Kruskal Wallis test was used to analyze the data.
 Results: The amount of wear of each material was found to be statistically significant (p< .05). No significant differences between the polished and glazed groups of Zir and LD were found but glazed CD was significantly more wear-resistant than polished CD (p< .05). 
 Conclusions: Wear is a phenomenon that can be affected by different factors such as microstructure and surface finishing of the materials. Wear resistance should be taken into consideration when choosing a material.

Abrasive Wear Behavior of Batch Hot-Dip Galvanized Coatings.

In recent decades, batch hot-dip galvanized (HDG) steel has proven itself in practical applications due to the good corrosion resistance of its components. Despite the importance of the mechanical-load-bearing capacity of these coatings, the wear behavior has, so far, only been investigated very sporadically and not systematically, so a quantification of the wear behavior and statements on the mechanisms are vague. Therefore, two body wear tests with bonded abrasive grain were carried out. Varying the friction rolls, load, and total number of cycles, the wear behavior was investigated. The mass loss and the layer thickness reduction were measured at different intervals. After the test, the microstructure in the cross-section and the hardness according to Vickers (0.01 HV) were evaluated. The results showed that the wear behavior of HDG coatings against abrasive loads can be characterized with the selected test conditions. Initially, the applied load removed the soft η-phase. As the total number of cycles increases, the η- and ζ-phases deform plastically, resulting in a lower mass reduction compared to that expected from the measured layer thickness. The characteristic structure of a batch HDG coating with hard intermetallic Zn-Fe phases and an outer pure zinc phase has demonstrated effective resistance to abrasion.

CRITICAL EVALUATION AND APPLIED ASPECT OF SWABHAVOPARAMVADA WITH SPECIAL REFERENCE TO THE THEORY OF INNATE DESTRUCTION.

Ayurveda is one of the world’s oldest medical systems and remains one of India’s traditional healthcare systems, as it is based on ancient writings that rely on a natural and holistic approach to physical and mental health. As per Ayurvedic philosophy, we know that the leading cause of any disease is Imbalance in the body, and so the treatment pattern also includes lifestyle management with natural therapies to attain and regain the balance between the body, mind, soul, and Prakriti, i.e., environment. The theory of natural destruction or self-healing process is termed ‘Swabhavoparamvada,’ where the term ‘Swabhav’ means the nature of a substance and ‘Uparama’ implies destruction.¹ This theory states that the physiological events in our body are unavoidable. Kala, i.e., time moves continuously, passes away, and is irreversible. The wear-and-tear theory states that bodies wear out over time. This theory can easily make sense when considering inanimate objects, from cars to clothes, that wear out and become less functional with time. Jara (Old) and Mrityu (Death) are Swabhavik vyadhi (natural), and these cannot be stopped. Tear and wear are the law of nature. This means the dhatu of the body is destroyed naturally, and this cannot be controlled by any process indicating Swabhavoparamvada. Understanding the concept of Swabhavoparamvada is very important for a physician to advise a good diet and lifestyle in continuity along with necessary interventions.

Trapping studies reveal phenology and reproductive behaviour in two solitary sweat bees (Hymenoptera: Halictidae)

Abstract To reconstruct behavioural changes that underpin evolutionary transitions between solitary and eusocial behaviour, we need detailed behavioural information about both solitary and eusocial species. Most behavioural studies of sweat bees have focused on sociality. We addressed the lack of detailed information about solitary species using pinned specimens of Lasioglossum leucozonium (Schrank) and L. zonulum (Smith) from Ontario (2003–2019) and Alberta (2016). We used weekly abundance of trapped bees to evaluate flight phenology (univoltine versus bivoltine), delineating two phases of flight activity, P1 and P2, before and after the first appearance of males, and evaluated female traits related to reproduction (body size, wear, and ovary development). All populations were confirmed to be solitary. The Ontario L. leucozonium and Alberta L. zonulum were univoltine, with P1 and P2 females being similar in size but P2 females more worn and with less-developed ovaries. Ontario L. zonulum were bivoltine, with P2 females being larger, more worn, and having more ovary development than P1 females, a unique pattern among bivoltine sweat bees. Contrasting observations between univoltine and bivoltine populations support the contention that solitary reproduction is not necessarily “simple” and that detailed information is needed to illuminate behavioural changes during bee social evolution.

Comparative evaluation of wear resistance between lithium disilicates and polymer infiltrated ceramics manufactured by computer aided design (CAD) computer aided manufacturing (CAM) against natural tooth enamel

Advances in CAD/CAM technology led to development of monolithic all ceramic restorations with superior esthetics like Lithium disilicate. But the major concern of ceramic materials was its wear towards the opposing enamel. Polymer infiltrated ceramics were developed by incorporating resin polymer in ceramics to produce esthetic stability of ceramics and low abrasive nature of composites and very few studies were done on this material. A total of 30 disc specimens were fabricated by CAD/CAM .15 discs of CAD/CAM lithium disilicate (IPS E.max CAD) and 15 discs of Polymer infiltrated ceramics of dimensions 10mmx3mm. They were named as group 1 (CAD/CAM Lithium disilicate) and group 2(Polymer infiltrated ceramics). 30 tooth specimens were mounted on auto polymerising acrylic resin blocks. Tooth specimens were placed on the upper member of the two body wear testing machine (Pin on disc wear and friction test rig, Magnum) and Lithium disilicate and polymer infiltrated ceramic disc specimens were positioned on disc of wear testing apparatus under constant load of 5kg (49N). The specimens were made to rub against one another in a rotating cycle to simulate oral wear cycle. The test was run for total of 10,000 wear cycles at 30rpm on wear machine for each sample. Wear of group 1 and group 2 and enamel wear of group 1 and group 2 was measured before and after wear test by profile projector.Wilcoxon test was done to compare the groups. Results showed that wear was greater in group 1 (Polymer infiltrated ceramics) compared to group 2 (CAD/CAM Lithium disilicate) and enamel wear of group 1 was greater than enamel wear of group 2. Advances in CAD/CAM technology led to development of aesthetic all ceramic restorations with superior mechanical properties such as CAD/CAM Lithium disilicate. But the major concern of ceramic materials is wear towards the opposing enamel. To meet the above requirements polymer infiltrated ceramics are developed by incorporating resin polymer in ceramics to produce esthetic stability of ceramics and low abrasive nature of composites. The restorative materials should not cause wear to opposing enamel and also should possess wear resistance similar to enamel for its success and longevity. This study was performed to evaluate the wear resistance of CAD/CAM lithium disilicate and Polymer infiltrated ceramics against natural teeth enamel.

Abstract 13302: Associations of Allostatic Load With Brain Macro-Morphology, Subclinical Cerebrovascular Disease, and Microstructural Integrity of White Matter Pathways: The Boston Puerto Rican Health Study

Introduction: Allostatic load (AL), a measure of overall body wear and tear, has been associated with structural and functional alterations of the brain, but the evidence remains scarce. We aimed to evaluate the prospective associations of AL with brain MRI measures in the Boston Puerto Rican Health Study (BPRHS). Research Questions: Whether AL is associated with 1) brain macro-morphology: brain age and volumes, 2) subclinical cerebrovascular disease: white matter hyperintensity (WMH) and brain infarcts, and 3) microstructural integrity of white matter (WM) pathways in Puerto Rican adults. Methods: Adults from the BPRHS cohort who provided blood and urine samples at baseline, 2-y, and 6-y visits and underwent MRI scans at 13-y visit were included in analyses (n=226). AL was evaluated as a composite score (0-11) of 11 physiological parameters in five body systems. An overall AL score was calculated by averaging the scores of the baseline, 2-y, and 6-y visits, with higher scores indicating greater dysregulation. We evaluated brain age and volumes using T1-weighted MRI, WMH and brain infarcts using T2-weighted MRI, and microstructural integrity of WM pathways using diffusion tensor imaging. Multivariable logistic regression models were used to examine the associations between AL and brain infarcts, and linear regression models were used for other MRI outcomes. Results: Mean age at baseline was 54.6 ± 6.6 y, with 79.2% female. Higher AL was associated with higher brain age z scores (β = 0.129, P = 0.031) and lower volumes of total WM, cerebral WM (especially parietal and temporal lobes), cerebellum, and brain stem. Higher AL was also associated with higher grades of WMH (β = 0.207, P = 0.024) and higher odds of small vessel infarcts [OR (95% CI) = 3.50 (1.56-7.87), P = 0.002], but not large vessel infarcts [OR (95% CI) = 1.33 (0.73-2.40), P = 0.348]. Diffusion tensor imaging parameters showed that participants with higher AL had more microstructural deterioration patterns in major WM pathways. Conclusions: Higher AL score was associated with brain macro- and microstructural disruptions and a higher risk of subclinical cerebrovascular disease, suggesting that AL may be a potential indicator of the need for early intervention in preventing neuronal damage in older adults.

REMOVAL OF RETAINED BULLETS FROM THE HIP JOINT IN CIVILIAN GUNSHOT INJURIES

Removal of bullets retained within joints is indicated to prevent mechanical blockade, 3rd body wear and resultant arthritis, plus lead arthropathy and systemic lead poisoning. The literature is sparse on this subject, with mostly sporadic case reports utilizing hip arthroscopy. We report on the largest series of removal of bullets from the hip joints using open surgical.We reviewed prospectively collected data of patients who presented to a single institution with civilian gunshot injuries that breached the hip joint between 01 January 2009 and 31 December 2022.We included all cases where the bullet was retained within the hip joint area. Exclusion criteria: cases where the hip joint was not breached, bullets were not retained around the hip area or cases with isolated acetabulum involvement.One hundred and eighteen (118) patients were identified. One patient was excluded as the bullet embedded in the femur neck was sustained 10 years earlier. Of the remaining 117 patients, 70 had retained bullets around the hip joint. In 44 patients we undertook bullet removal using the followingsurgical hip dislocation (n = 18), hip arthrotomy (n = 18), removal at site of fracture fixation/replacement (n = 2), posterior wall osteotomy (n = 1), direct removal without capsulotomy (tractotomy) (n = 5).In 26 patients we did not remove bullets for the following reasons: final location was extra-capsular embedded in the soft tissues (n=17), clinical decision to not remove (n=4), patients’ clinical condition did not allow for further surgery (n= 4) and patient refusal (n=1). No patients underwent hip arthroscopy.With adequate pre-operative imaging and surgical planning, safe surgical removal of retained bullets in the hip joint can be achieved without the use of hip arthroscopy; using the traditional open surgical approaches of arthrotomy, tractotomy and surgical hip dislocation.

2.4 GHz Compact Textile Antenna for Body Wear Application and Monitoring of Health Parameters

Background: This paper has described a textile-based body-worn antenna. When compared to standard flat and stiff antennas and circuits, this technology delivers superior mechanical and radio frequency performance. Textile antennas have several advantages, including small size, lightweight, ease of fabrication, and low cost. As a result of these advantages, textile antennas are gaining popularity these days. Objective: There are different applications of textile antennas, but the main application or aim is to wear them comfortably and observe different body signals for analysis of different health parameters, like temperature, heart rate, blood pressure, etc., as the compactness of the antenna bending losses is less. Methods: In the design of an antenna, jeans fabric is employed as the substrate because this material is sturdy, stiff, of little density, accessible, and inexpensive with electromagnetic properties ℇr = 1.6 and tan ẟ = 0.01, and copper is used for the conducting patch and ground. Result: This antenna operates in the industrial, scientific, and medical radio (ISM) band at 2.4 GHz with patch dimensions of 25 x 20 mm, making it proper for body-worn purposes. Because the antenna is so small, it can be readily mounted on an arm for health parameter monitoring with minimal bending. In sweaty conditions, it also operates in the ISM band. Conclusion: The simulation, fabrication, and body wear results are all included in the results section. As a result, these novel fibre antennas are useful to incorporate into shirts and coats for easy health monitoring with minimum loss.

Molybdenum powder coating on steel substrate to study three body wear resistance

Steel rollers are most commonly used in conveyor system across different industries like mining and construction. In the conveyor rollers used in mining industry, the steel specimen of the roller is in continuous contact with another metal of the same or different material rolling and sliding on that surface. In this motion of the roller, the third body i.e., the sand, grits and dust of various sizes may be entrapped in the interface of the roller material. The third body induced causes the wear due to its abrading action. To reduce this abrading action, a layer of molybdenum coating is developed on the steel substrate to improve its wear resistance by using the plasma spray technique, a thermal spray method. The experimental procedures were performed according to standard ASTM G65 method. The results were compared and tabulated in full factorial method. The SEM and EDAX results were obtained. The average specific wear rate [Ks] of the coated specimen is reduced by 30% when compared with the uncoated specimen.

In vitro degradation and dry sliding wear behaviour of AZ31-Sn/Al2O3 nano metal matrix composites in simulated body fluid for biomedical application

In this research, tin was added to the AZ31/2Al2O3 magnesium metal matrix composite to investigate its influence on degradation rate in the presence of simulated body fluid (SBF) and wear behaviour in dry conditions. The AZ31- xSn/2Al2O3 ( x = 0, 2, 4, 6, 8, and 10 wt%) composites were manufactured using the bottom pouring stir casting route. The microstructure of the manufactured AZ31/2Al2O3 and AZ31- xSn/2Al2O3 composites revealed that they were composed of the α-Mg solid solution and the intermetallic compound □-Mg17Al12, which was situated near the grain boundaries. When tin was added, the Sn-rich intermetallic compound Mg2Sn was formed, increasing the volume fraction of the Mg2Sn phase. Compared to AZ31/2Al2O3 composite, the wear test revealed that AZ31/2Al2O3 composites containing Sn particles exhibited a higher ability to generate more stable tribo-layers at higher applied loads, which protected the worn surface and reduced the wear rate. The wear resistance of composites was improved primarily by the behaviour of the tribo-layer in the wear process. The degradation rates (mm/year) of the AZ31 composites were carried out for 72 h in SBF. The degradation rate was reduced when the Sn content in the AZ31/2Al2O3 composite was increased to 6 wt% and then increased with further Sn addition. It was observed that when the amount of Sn particles increases up to 6 wt%, the severity of the degradation decreases.

Високоентропійний NiFeCrWMo сплав, отриманий в процесі механічного легування

In this work, the evolution of the structure and phase composition of the multicomponent Ni-Fe-Cr-W-Mo system during mechanical alloying (MA) of an equiatomic mixture of elemental metal powders in a planetary mill is investigated. The formation of the phase composition and structure of the powdered equiatomic high-entropy NiFeCrWMo alloy at different stages of mechanical alloying was determined by scanning electron microscopy, X-ray diffraction and X-ray spectral analysis. It was found that during 10 hours of МА, a single-phase high-entropy alloy with the structure of a BCC solid solution in the nanostructural state with a crystallite size of 22 nm and a lattice strain (microstress) of 0.61 % was formed. It was shown that the metal components were completely dissolved in the solid state during mechanical alloying, in contrast to their limited solubility under equilibrium conditions. Moreover, despite the different features of the formation of solid solutions in high-entropy alloys and traditional materials, the order of dissolution of element atoms in the lattice of a solid solution follows general principles and occurs depending on the melting point in the following sequence: Ni→Fe→Cr→Mo→W. The average particle size of the produced powdered NiFeCrWMo high-entropy alloy is 3.8 μm, and their shape is predominantly spherical or close to spherical. The microstructure of the particles of the powdered NiFeCrWMo high-entropy alloy at the early stage (1.5 hours) of mechanical alloying is a layered structure formed in the process of grinding, deformation, and cold welding of particles of elemental metal powders. After 10 hours of МА, the microstructure of the alloy particles becomes homogeneous and contains a small amount of WC inclusions as a result of milling due to wear of grinding bodies in the MА process. The obtained NiFeCrWMo high-entropy alloy can be used in the future as a component/binder for other composite materials, for example, hard alloys based on WC to replace Co. Keywords: high-entropy alloy, mechanical alloying, structure, phase composition, solid solution, nanostructure

Laser cladded TiO2–Cu composite coatings with high TiO2 content: Tribological properties by first-principle calculation

TiO2–Cu composite coatings with high TiO2 content were fabricated on Ti6Al4V alloy by laser cladding to improve its tribological properties in bioengineering field. The effects of TiO2 mass fraction on the microstructure and chemical compositions of obtained composite coatings were investigated using a scanning electron microscope and energy dispersive spectrometer, respectively, and the surface hardness was measured via a Vickers microhardness tester. The coefficients of friction and wear rates of TiO2–Cu coatings were investigated using a ball–on–disc wear tester against the tribo–pair of Si3N4 ball, and the wear mechanism was investigated using the first-principle calculation. The results show that the TiO2–Cu composite coatings are mainly composed of Cu4Ti3, TiO2 and Cu phases, in which the TiO2 plays the roles in friction reduction and wear resistance. The average COFs and wear rates of 90%TiO2–Cu composite coating are the lowest among the three types of TiO2–Cu composite coatings, which is attributed to the TiO2 solid lubricant and anti–wear effects. The wear mechanism is dominated by abrasive wear with slight adhesive wear, in which the two–body wear is increased with the increase of TiO2 mass fraction.

A Simple Technique to Remove an Incarcerated Ceramic Liner in Revision Hip Arthroplasty

Extraction of a well-fixed ceramic liner during revision total hip arthroplasty can be technically challenging, particularly when acetabular fixation screws prevent en bloc removal of the shell and insert without causing collateral damage to the adjacent pelvic bone. It is also important to remove the ceramic liner intact, as ceramic debris left in the joint may cause third body wear with premature articular wear of the revised implants. We describe a novel technique to extract an incarcerated ceramic liner when previously described strategies prove ineffective. Knowledge of this technique will help surgeons avoid unnecessary damage to the acetabular bone and optimize prospects for stable implantation of revision components.

Role of matrix alloy, reinforcement size and fraction in the sliding wear behaviour of Al-SiCp MMCs against brake pad material

Aluminium metal matrix composites were produced by a newly developed stirring device for stir casting with different matrix alloys, SiC particle fractions and sizes to investigate these parameters' influence on the materials' wear performance. The wear performance of the composites was evaluated with dry sliding pin-on-plate tests against a high-speed train brake pad, and the study of wear surfaces was completed by electron microscopy. The formation of an iron-based tribolayer during wear protected the metal matrix composite from further wear damage. The composite reinforced with 19% SiC particles sized 32 μm showed an increasing coefficient of friction during wear, and the wear surface showed traces of third body wear. The rare earth and transition metal added to the matrix alloy increased the hardness of the composite, and the intermetallic phases reduced the development of the Fe-based tribolayer. The composites with small SiC particles presented the Fe transfer on the exposed aluminium surface, with a lower wear rate and friction coefficient than other composites. The direct comparison of composites produced with different sizes of SiC particles highlighted that the relationship between the wear rate and the coefficient of friction of the composites and the brake pad showed a linear trend.