Local Wear Research Articles

What are the success rates of anterior restorations used in localised wear cases?

A systematic review and meta-analysis of the literature was carried out assessing the success and survival rate of anterior restorations used in localised wear cases. This also included assessment of posterior teeth re-establishing occlusal contact following use of the Dahl approach. Two large databases; Medline via OVID, and Scopus were used to identify existing literature. The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and Meta-analyses guidelines and used the PIO framework [1]. Grey literature was also searched. Publications written in English were included between Jan 1970 and Nov 2020. participants with localised anterior tooth loss. anterior composite restorations. success and survival rates of the composite restorations. Six cohort studies were included in the final analysis, with three prospective and three retrospective. These studies evaluated the success and survival rates of direct and indirect composite restorations, with a follow-up period ranging from 5 months to 10 years, which took place between 2000 to 2016. Extracted data included: author(s) and year, study type, number and age of participants, number of restorations, location for intervention, type of intervention (direct vs indirect), type of composite, increase in OVD (amount of increase and period to re-establish posterior occlusion), follow up period, definition of failure, number of failed restorations, assessment of intervention and longevity/survival rate. Risk of bias in individual studies was assessed using The Newcastle Ottawa quality assessment scale (NOS) for cohort studies. Outcome measures were standardised as success or survival: Success - restoration assigned category A on the modified US Public Health Service (USPHS) criteria. Survival - restoration assigned category A or B on the modified USPHS criteria. The restoration was considered a failure if any other grades were allocated on the modified USPHS criteria. Results were visualised using forest plots. Heterogeneity between studies was measured by I-squared statistic. Sensitivity analysis was performed for each outcome. The survival rates for composite restorations (direct and indirect) at 2-10 years follow-up was 88% (95% CI, 70-90%; I2 = 97%). When significant outliers from one study were removed, and re-analysed, the survival rates increased to 93% at 2-7 years follow-up (95% CI, 85-98%; I2 = 83%). Success rates for composite restorations over the same 2-10 year period was 68% (95% CI, 44-87%; I2 = 98%). Heterogeneity was generally considered high due to large variations in study design, sample size, type of intervention, and follow-up period. The success of the anterior composite Dahl approach in re-establishing posterior occlusion was reported at 85% (95% CI, 73%-94%), which took between 1.5 and 25.4 months. Anterior composite restorations had a high success rate over a period of 2-10 years in patients affected by localised tooth wear, which was higher over a 2-7 year interval. Although, the overall survival rates were considerably lower when accounting for minor and major types of restoration failure. This review supported continued use of anterior composites for restoring worn teeth, which had good short-medium term longevity. However, these conclusions should be interpreted with caution considering the quality of evidence, the heterogeneity of the studies and the limited number of studies included.

Three-dimensional-printed restorations for prosthetic rehabilitation of localized tooth wear using the Dahl concept: A case report

A 26-year-old man with localized tooth wear and demand for aesthetic rehabilitation of the anterior teeth presented to our department. The patient reported excessive consumption of energy drinks. Furthermore, multiple trauma and tooth fractures have occurred in the past. In the present case, three-dimensional (3D)-printed restorations were used to restore the vertical dimensions according to the Dahl concept. An indirect build-up using noninvasive restorations has been demonstrated to be beneficial due to its pleasing aesthetic outcome and the advantage of the 3D printing process. Adhesive bonding was adapted from previous studies using direct composite materials. Thus far, whether, and to what extent, the color of these restorations changes remains unclear. Furthermore, the material wear should be evaluated in future studies. Moreover, 3D-printed, noninvasive restorations made of a computer-aided design/computer-aided manufacturing hybrid material are suitable for the application of the Dahl concept. Aesthetic improvement in combination with minimally invasive pretreatment of the teeth and subsequent noninvasive restorations led to the rehabilitation of the vertical dimension of occlusion. After a follow-up period of two years, harmonious occlusal conditions were observed in the posterior region.

The Performance of Ankle- and Waist-Based Accelerometry in Quantifying Physical Activity Intensity Among 6- to 24-Month-Year-Olds: A Semistructured Laboratory Study.

We aim to quantify the performance of accelerometry in objectively measuring physical activity (PA) intensity among infants and toddlers. Thirty-eight 6- to 24-month-olds participated in a 30-min, semistructured lab visit. Twenty-three (61%) children could walk independently. Children engaged in a variety of activities while wearing accelerometers on each ankle and at the waist. Visits were video recorded, and study team members independently coded the first three 5-s epochs of each minute for PA intensity using a 5-level scale ranging from 1 = completely sedentary to 5 = moderate-to-high intensity. Interrater agreement for PA classifications was excellent (median kappa per child = 0.85). A series of logistic regression models were fit to find the vector magnitude threshold per 5-s epoch that differentiated activity intensity above each PA level with ≥ 80% sensitivity. Analyses included 3191 epochs; a median of 88 epochs per child. The classification performance applying all thresholds concurrently for the five PA intensity levels was poor for each wear location (agreement < 50%, kappa < 0.25). Classification improved when concatenating intensity levels, with the best performance comparing sedentary (levels 1-2) to nonsedentary (levels 3-5) and using data from the left ankle device: agreement ≥ 77.6%, kappa ≥ 0.44. Applying those novel thresholds to predict the total time spent in level 3-5 activities over all coded epochs using linear regression performed as well as using the sum of vector magnitude across epochs when using data from the left ankle device. Overall, the performance of the left ankle wear location was similar to the right ankle wear location and superior to the waist location. Ankle-worn accelerometry had adequate validity to classify in-the-moment nonsedentary behaviours and total time spent nonsedentary over a time interval among this sample of infants and toddlers. While caution is warranted when generalizing these lab-based findings to naturalistic settings, findings provide insight into objective measures of PA for this age range.

Pertanggung Jawaban Hukum Pengelola Parkir Terkait Legalitas Usahanya

Introduction: Parking service users who are harmed because there are managers and parking attendants who manage a parking lot illegally, they do not have direct permission from the local government and there is a loss of consumer belongings, and the consumer asks for compensation for the loss but the parking officer does not want to be responsible for the reason that it is not his responsibility, this is of course the responsibility of the parking manager if the parking officer does not want to be responsible for the The loss. Purposes of the Research: The responsibility of the parking manager, this of course causes losses experienced by parking lot users or consumers due to the absence of responsibility from the parking manager. Methods of the Research: The research method used is a type of normative research that is carried out by researching library materials or secondary data, legal materials consisting of primary legal materials, secondary legal materials, and tertiary legal materials, in the procedure for collecting legal materials is carried out by examining legal materials, preparing legal materials, systematically processing and analyzing legal materials. Results Originality of the Research: The results of this study show that the legality of parking attendants, namely parking managers, must have official permits from the local government and wear uniforms or clear identification. Sanctions given to illegal parking attendants include verbal or written reprimands and administrative fines, as well as the responsibility of parking managers to parking service users. In the event of loss of consumer goods, the parking manager is responsible for replacing the lost consumer goods, because the task of the parking manager is to protect the consignment items belonging to consumers as if they belong to them and must be returned in their original form.

Study on the mechanism of erosion and wear of elbow pipes by coarse particles in filling slurry

Coarse particles in filling slurry are the primary factor causing wear in filling elbow pipes, and the wear mechanism of these particles on the pipes is influenced by various factors. To study the erosion and wear mechanism of elbow pipes caused by coarse particles, the motion state of coarse particles under different curvature radii, coarse particle gradations, and pipe diameters was investigated using a simulation method based on the coupling of Fluent and EDEM software, grounded in theories of fluid mechanics, rheology, and solid–liquid two-phase flow. The study explored the impact patterns and locations of wear induced by coarse particles on filling elbow pipes. The analysis results indicate that increasing the curvature radius leads to more punctate wear at the elbow and upstream wear. Increasing the proportion of finer particles in the coarse particle gradation forms a better cushioning layer and reduces erosion wear. Enlarging the pipe diameter shifts the high-low concentration boundary of coarse particles towards the elbow outlet and reduces erosion wear. The research findings provide significant references for optimizing coarse particle gradation and preventing pipe wear.

Numerical investigation on tooth surface waviness in continuous generating grinding of electric vehicle gears considering the main shaft vibration and grinding worm wear

The objective of this paper is to present a numerical approach to investigate the formation mechanism of tooth surface waviness in CGG of electric vehicle gears while independently analyzing each influencing factor and ignoring the mutual influences between them. A tooth surface waviness simulation model is proposed considering the system vibration and tool wear. According to the characterization of grinding worm wear and the main shaft vibration in CGG, the grinding worm wheel and the grinding trajectories are modeled. Based on the analysis of the geometric contact characterizations through the whole grinding process, tooth surface topography is modeled, and tooth surface waviness is extracted. By comparing the tooth surface waviness in the frequency domain, the influence of grinding worm local wear, global wear, and the main shaft vibrations on tooth surface waviness is studied. Local wear and global wear affect tooth surface waviness differently by changing the amplitude and the distribution pattern of the frequencies. The main shaft vibrations have limited direct impacts on the amplitude in profile and flank spectrums, among which the vibration Z plays a leading role.

Influence of local tool angles and cutting conditions on abrasive wear in CFRP drilling

During drilling carbon fiber-reinforced polymer (CFRP), tool wear progresses relatively quickly and significantly increases workpiece defects. Optimizing the drilling process and selecting the appropriate tool design are essential for minimizing wear and preventing defects in the workpiece. Conventional investigation into tool wear progression during drilling often involves measuring the maximal wear in proximity to the outer corner. The diverse and pronounced variations in both geometric conditions and kinematic factors encountered along the tool edges in drilling operations result in considerable differences in observed wear.Consequently, an imperative need exists to enhance the comprehension of the micro-geometry evolution of tools on a localized scale, using parameters that describe the local cutting situation. This paper presents a robust methodology aimed at following the evolution of local wear along the cutting edge within the material flow plane (Poe). This method will contribute to a better understanding of wear phenomena with the variation of cutting parameters and angles. Finally, empirical models will correlate the criteria describing wear patterns on the rake and flank faces with influential parameters. This will help in predicting local wear and optimizing the manufacturing of cutting tools for improved lifespan.

Success and Survival of Composite Resin Restorations for the Management of Localized Anterior Tooth Wear: A Systematic Review and Meta-Analysis.

To systematically review the literature and assess the success and survival rates of anterior composite restorations used in the management of anterior tooth surface loss, and to estimate complete posterior occlusion re-establishment when a Dahl approach is utilized. An electronic search was performed in the following databases: MEDLINE via Ovid and Scopus, for articles published from 1970 to November 2020. The systematic review was performed according to the PRISMA and Meta-analyses guidelines. Only randomized and non-randomized clinical trials, and Cohort studies that involved the exclusive use of direct/indirect anterior composite restorations for the management of localized anterior tooth wear were included. From the 724 studies identified through the initial search, six studies fulfilled the inclusion criteria and were included in the review; three prospective and three retrospective. In total, 141 patients received 1068 direct and indirect composite restorations. Follow-up periods ranged between 5 months and 10 years. The survival rate for anterior composite resin restorations reported in this review was 88% (95% CI: 70% to 98%) over a period of 2 and 10 years; however, high heterogeneity was observed amongst included studies; (I² = 97%). Sensitivity analysis reported survival rates of these restorations of 93% (95% CI: 85% to 98%) over a period of 2 and 7 years, (I² = 83%). Success rates were reported for these restorations of 68% (95% CI: 44% to 87%) over a period of 2 and 10 years, high heterogeneity; (I² = 98%). The success of composite Dahl in re-establishing posterior occlusion was 85% (CI: 73% to 94%). The result of this systematic review and meta-analysis support the use of anterior composite restorations as a short-medium term option for the management of tooth wear. In the long-term, patients should be informed that these restorations will require monitoring, repairs, or replacements.

Modeling of Frictional Inter-Bristle Contact in Brush Seals With Shaft Radial Movements

Abstract Brush seals are utilized in turbines to minimize leakage flows and enhance thermal efficiency. Their widespread use faces challenges like pressure-stiffening and hysteresis, leading to unpredictable performance. This work introduces an advanced numerical model to simulate inter-bristle frictional contact, shaft and backing ring interaction, and three-dimensional bristle bending. The model is adopted to investigate multi-bristle brush seal's behavior under shaft radial movements and pressure loading. Backing ring friction emerges as a vital factor in hysteresis modeling, lessening the impact of shaft friction. When the shaft retracts, modeling the bristle tip clearance becomes important. The clearance greatly increases leakage flow rate and changes bristles' aerodynamic loading distribution. With clearance, the normal force on upstream bristles rises markedly, opposing bristle hang-up, while the axial force decreases in downstream bristles, alleviating the bristle pack compression. Considering these factors, an improved model for pressurized seals in the shaft retraction phase is developed and compared to experimental data in the literature. Frictional inter-bristle contact significantly modifies the distribution of local tip force through the pack. These effects would influence localized wear and heat generation across the brush seal pack, shedding light on the uneven wear patterns often observed in experiments. The present high-fidelity model can capture these complex interactions, offering a means to deepen our understanding of the physical mechanisms underpinning novel brush seal designs.

Occlusal parameters and wear of artificial teeth in complete dentures with lingualized versus bilateral balanced occlusion: a randomized clinical trial

ObjectiveThis study aimed to assess the occlusal contact area (OCA), occlusal contact number (OCN), bite force, and artificial tooth wear in complete dentures with lingualized and bilateral balanced occlusion.MethodsEdentulous participants who fulfilled the inclusion criteria were divided into the three groups as follows: group I, dentures with lingualized occlusion using interpenetrating polymer network artificial teeth; group II, dentures with lingualized occlusion using double cross-linked artificial teeth; and group III, dentures with bilateral balanced occlusion using anatomical micro-hybrid resin teeth. The silicone techniques were used to assess the OCA and OCN of the mandibular dentures and the Dental Prescale II was used to evaluate the bite force at the 2-week, 3-month, and 12-month follow-up visits. Occlusal contact analyzer software was used to assess the maxillary and mandibular posterior tooth wear at the 12-month follow-up visit. All data was analyzed using the SPSS software.ResultsThe OCA of group III was significantly higher than that of groups I and II at the 2-week follow-up visit, whereas group I was considerably higher than groups II and III at the 3-month and 12-month follow-up visits. The OCN of the three groups exhibited significant differences at all three follow-up visits. Groups I and II had significantly lower bite force than Group III at the three follow-up visits. At the 12-month follow-up visit, groups I and II had significantly higher wear than Group III.ConclusionsAs the duration of use increases, the occlusal contact area of complete dentures increases, regardless of the occlusal schemes. The bite force of lingualized occlusion is typically lower than that of bilateral balanced occlusion. The wear locations of artificial teeth differ between the two types of occlusal schemes. (Retrospectively registered: The Chinese Clinical Trial Registry, No. ChiCTR2300073420(11/07/2023))

Modeling and Measurement of Tool Wear During Angular Positioning of a Round Cutting Insert of a Toroidal Milling Tool for Multi-Axis Milling

The aim of this study was to develop a concept for an angular positioning method for a round cutting insert in a torus cutter body dedicated to the multi-axis milling process under high-speed machining cutting conditions. The method concept is based on a developed wear model using a non-linear estimation method adopting a quasi-linear function. In addition, a tool life model was developed, taking into account the cutting blade work angle parameter, the laser marking method for the round cutting insert, and a wear measurement methodology. The developed tool wear model provides an accuracy of 90% in predicting the flank wear of the cutting blade. The developed procedure for angular positioning of the round cutting insert enables the entire cutting edge to be fully utilized, extending the total tool life. In addition, the measured largest defect values between the worn cutting edge and the nominal outline of the round cutting insert indicate the location of notching-type wear.

Preparation of iron-based composites reinforced with submicron/nano-sized TiC ceramic particles by in-situ reaction in melts and one-step integrated hot pressing densification

The iron matrix composites strengthened with submicron/nano-sized TiC particles dopping with different alloying elements (Mo, Ni) were prepared by melt-in-situ reaction and one-step integrated hot compaction. The results indicate that the incorporation of Mo and Ni through alloying treatment can refine ceramic particles, and thus lead to a significant improvement in the uniformity of the microstructure. The mismatch between the TiC and α-Fe is significantly reduced and the interface stability is enhanced. The yield strength of 1904 MPa and maximum compressive strength of 2605 MPa of TiC/Fe composite with the addition of 4 wt.% Mo are 28.3 % and 23.9 % higher than those without alloying elements, respectively. The yield strength of 2032 MPa and maximum compressive strength of 2815 MPa of TiC/Fe composite with the addition of 2 wt.% Ni are 36.9 % and 33.9 % higher than those without alloying elements, respectively. First-principles calculation results indicate that Mo atoms tend to accumulate at the interface, while Ni atoms can easily substitute Fe atoms, resulting in the formation of a FeNi solid solution. The primary strengthening mechanisms of TiC/Fe composites dopping Mo are the refinement strengthening of ceramic particles. The interface bond between Fe matrix and TiC particles is also strengthened. The addition of Ni primarily leads to solid solution strengthening and grain refinement. This TiC particle manipulating strategy within Fe melt can effectively optimize the corresponding interfacial bonding, lead to comprehensive improvement in property, and finally realize the expanding application at specific wear locations.

Modeling wear of different surface layers of agricultural tools in soil abrasive mass

Uniform quantitative measures have not been developed to identify the areas with the greatest intensification of tool wear. Therefore, this paper developed original approach to assess the wear of cutting elements by identifying the intensity of local volumetric wear. A tribological test was conducted under natural operating conditions in two soil types: sandy loam and loam. The specimens were mounted on a 9-tined cultivator with spring tines aggregated with an agricultural tractor. A method was developed to discretise the local volume changes of a component using surface scanning models developed from 3D scanning. The notion of the rake angle has been defined, allowing the assessment of changes in the shape of the element during wear. The practical usefulness of the developed method was verified on three types of surface layers, i.e. 38GSA steel, ELHARD70 deposited on it, and a G10 layer of carbide. For each of the tested variants, local volumetric consumption was defined based on the identification of the wear grid. These should be the basis for developing the technology of surface strengthening of elements. The work confirmed the complexity of the process of wear of working elements in natural soil conditions, presented in many research works. A different course of wear of the 38GSA steel and the Elhard 70 weld layer was shown, depending on the type of treated soil. In the case of samples made of G10 cemented carbide, the largest volumetric wear for heavy soil occurred outside the place of reinforcement application. The highest volumetric wear in the front zone was recorded for 38GSA steel in heavy soil. Wear results from the modelling are similar to those obtained from the experiment under natural conditions in light soil using the nominal model (CAD) and the actual friction surface.

Multi-scale modeling and mechanical performance analysis of finger seals with plain woven C/C composite

The application of carbon fibers reinforced carbon matrix (C/C) composite can solve the local wear of metallic finger seals effectively. However, the performance of C/C composite finger seal is complex and variable, which further decreases the sealing performance and life. Therefore, a method of multi-scale modeling and mechanical performance analysis for plain woven C/C composite finger seals was conducted. The circumferential finger beams of C/C composite were modeled by multi-scale structural analysis and weaving simulation. The radial static and dynamic stiffness characteristics of finger beams were investigated. The results showed that the radial static stiffness of the finger beam with three layers was about 3 times that with single layer. The radial stiffness of circumferential finger beams presented a periodic distribution pattern with a period of 90°. The radial dynamic stiffness of C/C composite finger beams increased with the excitation displacement amplitude and rotor speed. But the magnitude and fluctuation degree of dynamic stiffness were greater than those of static stiffness. A large difference in radial stiffness will lead to local wear and hysteretic leakage. This study lays a foundation for the analysis and optimization of the hysteresis and wear characteristics of C/C composite finger seals.

Study of fretting wear mechanisms of complete contacts

The Ti-6Al-4V fretting wear of complete contacts on a proving ring-like rig is investigated in this paper. Under this contact configuration, the Ti-6Al-4V alloy exhibited distinctive fretting wear behaviors. Especially in the continuous wear zones of the fretting specimen and pad, a paired continuous pit and peak were formed, respectively, and moved inward as the continuous wear zones expanded. To explain these fretting wear behaviors of the fretting configuration, a novel phenomenological fretting wear model is proposed in this paper. Additionally, due to the failure of the conventional FE method with a constant wear coefficient to simulate the fretting wear, a new local wear coefficient model, which is position-dependent and time-dependent fretting, is also proposed in this paper.

Microstructure, Mechanical, and Tribological Properties of Nb-Doped TiAl Alloys Fabricated via Laser Metal Deposition.

TiAl alloys possess excellent properties, such as low density, high specific strength, high elastic modulus, and high-temperature creep resistance, which allows their use to replace Ni-based superalloys in some high-temperature applications. In this work, the traditional TiAl alloy Ti-48Al-2Nb-2Cr (Ti4822) was alloyed with additional Nb and fabricated using laser metal deposition (LMD), and the impacts of this additional Nb on the microstructure and mechanical and tribological properties of the as-fabricated alloys were investigated. The resulting alloys mainly consisted of the γ phase, trace β0 and α2 phases. Nb was well distributed throughout the alloys, while Cr segregation resulted in the residual β0 phase. Increasing the amount of Nb content increased the amount of the γ phase and reduced the amount of the β0 phase. The alloy Ti4822-2Nb exhibited a room-temperature (RT) fracture strength under a tensile of 568 ± 7.8 MPa, which was nearly 100 MPa higher than that of the Ti4822-1Nb alloy. A further increase in Nb to an additional 4 at.% Nb had little effect on the fracture strength. Both the friction coefficient and the wear rate increased with the increasing Nb content. The wear mechanisms for all samples were abrasive wear with local plastic deformation and oxidative wear, resulting in the formation of metal oxide particles.

Effect of WC content on the microstructure and wear resistance of Laser-cladded WC/Ni60A composite coatings

In this study, WC/Ni60A composite coatings with various WC contents were prepared on the surface of the TC4 titanium alloy using laser cladding. SEM, EDS, XRD, microhardness testing, and friction-wear performance testing were performed to characterize the coatings. The results revealed that an increase in the WC content reduced the coating dilution rate and increased its porosity. The microstructure of the composite coating included WC, Ni3Ti, Ni17W3, and TixW1−x species as well as carbides and borides. With increasing WC content, the wear rate decreased, and the wear mechanism changed from microabrasion and adhesive wear to localized adhesive wear. The coating with 45 wt.% WC showed the best wear resistance for the denser and more uniform distribution of its hard phase.

Experimental investigations and finite element simulation for predicting wear life of overrunning clutches

An overrunning clutch, generally known as a freewheel clutch, is a direction dependent torque transmitting device that works on the principle of wedge friction. The overrunning wear characteristics of freewheels are studied using pin-on-disc tribometry. The wear experiments for freewheels are performed at accelerated loads to promote wear in a short period. The overrunning wear life of the clutch under operating conditions is predicted using an appropriate load-life relationship. A finite element-based Archard’s wear model is implemented as a numerical strategy to evaluate the wear profile. The maximum local wear for various loads is computed using experimentally obtained wear and friction coefficients. The numerical simulation is performed with an adaptive mesh technique utilizing incremental nodal displacements to predict surface wear. The experimental and numerical results are compared in terms of wear characteristics. The numerical wear results are almost 11% higher than the experimental results. The wear life of an overrunning clutch is predicted in terms of overrunning speed based on the wear amount.

Rate of polyethylene wear correlates with earlier glenoid implant failure in anatomic total shoulder arthroplasty with cemented all-polyethylene glenoid components

BackgroundGlenoid component loosening is the most common cause of anatomic total shoulder arthroplasty failure, and osteolysis is a common intraoperative and radiographic finding associated with these failed arthroplasties. While preclinical testing can estimate failure mode and wear rates in the laboratory, there is limited in vivo data measuring polyethylene wear rate and location. MethodsUsing an institutional review board–approved total joint arthroplasty retrieval collection, 56 cemented all-polyethylene glenoid components from eleven different manufacturers were analyzed for in vivo dimensional change. We used the differential thickness measurement between the anteroposterior and superoinferior axes of each radially symmetrical implant to determine the dimensional change along that axis. A physiologic wear vector was determined for each retrieved device. ResultsThe implants had a median dimensional change of 0.13 mm/year (range 0.01-1.01mm/year) and the 25th and 75th percentiles were 0.060 and 0.22 mm/year, respectively. The average time to revision of devices with <0.1mm/year of wear was 140.9 months, while the averages for devices between 0.1-0.2mm/year and ≥0.2mm/year were 80.7 and 54.0 months, respectively. Devices with ≥0.2mm/year of wear had significantly shorter time to revision than those with <0.1mm/year (P = .0006). The devices had a similar material loss distribution in both superior-inferior and anterior-posterior directions, with 29 (52%) devices having a greater material loss in the superior-inferior distribution and the remaining 27 (48%) devices in the anterior-posterior axis. The physiologic wear vector had a mean of 47.3 degrees, with a relatively even distribution across all angles, suggesting that glenoid component loosening can occur along multiple axes. ConclusionWe conclude that polyethylene wear is a contributing factor for early failure of cemented all-polyethylene glenoid implants and that anatomic total shoulder arthroplasty may benefit from advances in polyethylene processing. We also suggest that in vitro testing of new polymers and designs should incorporate motion vectors beyond the traditional IS rocking horse test.

Experimental, analytical, and numerical quantification of the Marangoni effect in static refractory finger test

This study investigated the local corrosion of alumina and magnesia refractory in CaO–Al2O3–SiO2–MgO slag due to the Marangoni effect, which is a key factor for localized wear in different industrial processes, using experimental, analytical, and numerical approaches. The objective is to explore the Marangoni effect using computational fluid dynamics simulation aiming to provide insights into the dominant slag flow patterns influencing refractory corrosion and to determine whether the observed corrosion groove can be attributed solely to the Marangoni effect. Static finger tests were conducted at temperatures of 1500 and 1550 °C employing a continuous wear testing device. A two-dimensional axisymmetrical section model of the test assembly was created, incorporating concentration-dependent surface tension gradients and surface tension forces to replicate the Marangoni flow. As the surface-tension simulation required time steps in the order of 10−5 s, modeling up to the experimental time scale cannot be realized. Consequently, the simulation outcomes were extrapolated to anticipate the groove radii of the experimental corrosion steps. Corrosion rates were derived from measurements and analytical methodologies. Established analytical equations for corrosion under surface-tension-flows were adapted to enhance the accuracy of corrosion rate estimation. However, the analytical considerations yielded poor estimates. Meanwhile, the employed simulation model successfully generated plausible predictions of the Marangoni flow. Drawing from the extrapolated simulation outcomes, the projected groove radii exhibited a close correspondence to the measured values, demonstrating a relative error of approximately 3 %, 11 %, and 15 % for the magnesia system at 1500 °C and alumina systems at 1500 and 1550 °C, respectively. Taking into account the uncertainties inherent in the methodological approach, the disparities in the alumina values suggest the involvement of mechanisms beyond the Marangoni effect in the localized wear. Consequently, this study effectively clarifies the impact of the Marangoni effect on the local wear of the examined material systems.