Continuous Wear Research Articles

Simulation and experimental verification of the orthogonal friction continuous wear of PTFE-Kevlar fabric liner

Woven fabric liners, which are customizable and maintenance-free, have extensive applications in self-lubricating spherical bearings. However, owing to the orthogonal anisotropy and non-homogeneous characteristics, their frictional and wear behaviors are complex. Currently, average performance testing is primarily based on long-term macroscopic wear experiments. However, unobservable parameters such as mesoscopic stress and pressure distribution in liners are bottlenecks in the experimental exploration of wear sources and mechanisms. Therefore, an innovative strategy for modeling orthogonal friction and continuous wear in non-homogeneous liners is presented. This approach has the potential to overcome experimental limitations and significantly expedite liner design and cost-effective validation. The initial step involves establishing a mesoscopic voxel-based planar model of the liner that maintains the topological relationship during wear processes. This is achieved by introducing a circular voxel mesh and spatial transformation methods. Based on orthogonal friction and wear assumptions, separate constitutive models for orthogonal friction and wear are developed. Using the CETR UMT-3 friction and wear testing machine, GCr15 is selected as the counterface material, the pin disc wear method is adopted to conduct sliding test on PTFE and Kevlar fibers, and the required wear constitutive parameters are fitted. Furthermore, incremental equations for the total wear are derived. An element wear fusion strategy is introduced. This approach leads to the development of a continuous wear algorithm for liners and subsequently to the establishment of a voxel-based finite element model with continuous wear capability in the form of a circular voxel grid. This method transcends experimental methods and allows for the determination of the mesoscopic contact pressure, stress distribution, and variations in the contact material composition patterns of liner. The accuracy of the average macroscopic wear prediction is validated experimentally. This method has the potential for practical applications in bearing design.

Wear mechanisms and failure analysis of a tool used in refill friction stir spot welding of AA6061-T6

Investigating tool wear in refill friction stir spot welding (RFSSW) is essential for understanding its limitations and improving its efficiency. Increasing the tool's service life is important to push the technology's readiness level and transfer the technology from the laboratory to industrial applications. In this study, the quasi-static lap shear performance of AA6061-T6 similar welded spots was investigated and tool wear was continuously monitored until tool failure at 3450 welding cycles. Furthermore, the fundamentals of the wear mechanisms in RFSSW were further elucidated. The investigation shows that it is possible to achieve steady quasi-static lap shear performance of the spot welds over advancing tool wear by adjusting the heat input to compensate for losses in frictional heat generation efficiency (related to tool profile changes by abrasion). A subsequent tool failure case analysis showed the main causes for the continuous wear degradation of the shoulder. Tool wear was driven by plastic deformation of the hot-work tool steel and subsequent break-out of tool steel ridges, introducing big hard particles into the contact region between the moving and rotating tools. In addition, the formation and detachment of Fe-Al intermetallic compounds counteract with the rotating tools and increase tool wear.

Investigating the Impact of Pad Groove Depth Reduction on Process Variation in Oxide Chemical Mechanical Polishing

Abstract The groove depth of a polishing pad diminishes due to continuous wear from the diamond conditioner. Over the course of approximately 20 hours of use, this reduction in groove depth enhances slurry flow across both the pad grooves and surface. A fluid simulation analysis indicates that the new slurry mass fraction at 0.51 seconds increases from 72.34% for an 850 µm groove depth to 100.00% for a 250 µm depth. Consequently, polishing performance metrics including removal rate, within-wafer nonuniformity (WIWNU), and added defects exhibit variations commensurate with groove depth alterations. To explore the influence of process parameters on these polishing performance metrics, oxide film polishing experiments were conducted using pads with initial groove depths of 250, 500, 750, and 850 µm. The effects of process parameters, including pad cut rate, retainer ring pressure, and slurry flow rate on polishing were separately examined across different groove depth pads. Generally, shallow groove pads display improved removal rates but worse WIWNU. Additionally, the maximum surface temperature of the pads was recorded, serving as an indirect indicator of individual parameter effects. The findings have implications for advanced process control, guiding the optimization of polishing protocol in consideration of pad lifetime.

Extraction and classification of vibration features of rolling element bearing with increasing the rotational speed

Machinery components degrade over time due to continuous use. A reliable prognosis framework can improve machinery health by monitoring the behavior of its parts and providing warnings before critical failures occur. Bearings, which are essential components of rotating machinery, help maintenance personnel assess the machine’s condition during continuous wear. In this study, vibration data from roller bearings under various conditions and faults were collected. The Vibration analysis technique was employed to detect and classify different faults in bearings based on the characteristics of the vibration signals generated by the machinery. Faults can be detected, diagnosed, and classified by analyzing bearing vibration signatures using techniques such as frequency analysis, time-domain analysis, spectral analysis, and kurtogram classifiers. This enables appropriate maintenance actions to be taken in time, preventing further damage or failures.

Electrical contact reliability investigation of high-speed electrical connectors under fretting wear behavior

Fretting is one of the common phenomena during the use of electrical connectors, which is usually affected by the working environment and has a significant impact on the electrical contact life. In this work, the influence of different fretting wear conditions on electrical contact failure is studied by combining theoretical analysis, finite element simulation and experimental verification. The mechanical and electrical properties are related through experiments in different environments. It can be concluded that the main causes of electrical contact failure are contact structure deterioration and surface coating loss. Increased fretting cycles aggravate the surface fretting wear of high-speed electrical connectors. The failure of electrical connectors can be delayed by a decrease in frequency and amplitude in addition to an increase in coating thickness. The insertion and withdrawal force gradually decreases due to continuous wear. The failure mechanism of electrical contact during wear is also explained. It provides theoretical guidance for predicting the life of electrical connectors.

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.

Flow-induced erosion modelling of cohesive material with coupled CFD-DEM approach

Erosion is one of the continuous wear mechanisms in cohesive materials caused by the shear stress applied by the fluid flow at the liquid–solid interface. The erosion resistance of cohesive materials is significantly influenced by the strength of the cohesive bonds that hold the particles together, increasing the complexity of the mechanism. The erosion rate of cohesive materials depends on the critical shear stress (CSS) and the erodibility coefficient at the surface. The current understanding of the relationship among the inter-particle bond strength, CSS, erodibility coefficient, and their respective contributions to the flow-induced erosion process is still lacking; therefore, it cannot be adequately described mathematically. The present research offers a coupled computational fluid dynamics (CFD)–discrete element method (DEM) approach to visualize and quantitatively analyze the flow-induced erosion in cohesive materials. The capability and accuracy of the developed model were validated using experimental data available in the literature. A cohesion model was then employed to describe the strength of the cohesive bond, and the effects of the cohesion energy density (CED) on the CSS and erodibility coefficient were investigated. The analysis indicated that for cohesive materials, the non-dimensional CSS not only is affected by the particle Reynolds number but also strongly depends on CED. The simulation results indicated that by increasing the CED value from 500 to 900kJ/m3, the CSS increased by 25 %, and the erodibility coefficient decreased by 62 %. The proposed CFD–DEM approach can effectively estimate the erosion initiation and erosion rate of cohesive materials in different applications and geometries.

Precise Lubrication and Protection of Cartilage Damage by Targeting Hydrogel Microsphere.

Osteoarthritis (OA) is a degenerative bone and joint disease characterized by decreased cartilage lubrication, leading to continuous wear and ultimately irreversible damage. This situation is particularly challenging for early-stage OA, as current bio-lubricants lack precise targeting for small inflammatory lesions. In this work, an antibody-mediated targeting hydrogel microspheres (HMS) is developed to precisely lubricate the local injury site of cartilage and prevent the progression of early OA. Anti-Collagen type I (Anti-Col1) is an antibody that targets cartilage injury sites in early OA stages. It is anchored on a HMS matrix made of Gelatin methacrylate (GelMA) and poly (sulfobetaine methacrylate) (PSBMA) to create targeted HMS (T-G/S HMS). The T-G/S HMS's high hydrophilicity, along with the dynamic interaction between its surficial Anti-Col1 and the Col1 on cartilage injury site, ensures its precise and effective lubrication of early OA lesions. Consequently, injecting T-G/S HMS into rats with early OA significantly slows disease progression and reduces symptoms. In conclusion, the developed injectable targeted lubricating HMS and the precisely targeted lubrication strategy represent a promising, convenient technique for treating OA, particularly for slowing the early-stage OA progression.

A polyester- stainless steel based smart wristband sensor for skin temperature monitoring

This study presents the development and characterization of a novel textile-based wristband sensor for continuous temperature monitoring. The sensor, woven with a blend of polyester-stainless steel and polyester-cotton yarns, exhibited high sensitivity (0.0315/°C) and a rapid response time (∼35 sec). Stainless steel was selected for its excellent electrical conductivity and biocompatibility, crucial for accurate and safe skin contact applications, while polyester and cotton contribute its lightweight, breathable, and durable properties, ensuring prolonged comfort and wearability. Through systematic testing and optimization, the sensor’s sensitivity was fine-tuned by adjusting the number and length of conductive yarns. The study also introduced a theoretical resistance equivalent model, comparing its theoretical sensitivity with experimental findings. The sensor, lightweight and cost-effective, proved comfortable during 8–10 h of continuous wear. This study addresses challenges faced by existing textile temperature sensors and offers a reliable alternative with high linearity, repeatability, and suitability for individuals with sensitive skin.

Sex differences in cervical disc height and neck muscle activation during manipulation of external load from helmets.

Neck pain associated with helmet-wear is an occupational health problem often observed in helicopter pilots and aircrew. Whether aircrew helmet wearing is associated with physiological and biomechanical differences between sexes is currently unknown. This study investigated neuromuscular activation patterns during different helmet-wearing conditions. The helmet load was manipulated through a novel Helmet Balancing System (HBS) in healthy, non-pilot male and female participants (n=10 each, age 19-45years) in two phases. Phase A assessed the acute effects of helmet-wear on neck muscles activation during head movements. Phase B examined changes in muscle activity and cervical disc height after wearing a helmet for 45 min. In Phase A, muscle activity was similar between sexes in many movements, but it was higher in female participants when wearing a helmet than in males. The HBS reduced muscle activity in both sexes. In Phase B, female participants exhibited a greater level of muscular fatigue, and male participants' cervical disc height was significantly decreased [5.7 (1.4) vs. 4.4 (1.5)mm, P<0.001] after continuous wearing. Both sexes showed no significant change in muscle fatigue and disc height [male: 5.0 (1.3) vs. 5.2 (1.4)mm, P=0.604] after applying HBS. These findings demonstrate sex-specific physiological and biomechanical responses to wearing a helmet. They may indicate different postural and motor control strategies, associated with different neck pain aetiologies in male and female aircrew, the knowledge of which is important to reduce or prevent musculoskeletal injuries associated with helmet wearing.

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.

Результаты двухлетнего применения очков с высокоасферичными микролинзами для контроля миопии у детей

Purpose. To study the efficacy of spectacle lenses with highly aspherical lenslets (Stellest™) on refraction, axial length (AL) and accommodation in children with progressive myopia. Methods. The study included 259 children (518 eyes) aged 7 to 16 years (10.0±1.7 years) with progressive myopia from –0.5 D to –7.0 D (mean cycloplegic spherical equivalent refraction –2.6±1.6 D), astigmatism was present in 31 % of cases. Spectacles with Stellest™ lenses were always prescribed for continuous wear (at least 12 hours per day). Follow-up period was 6 months in 129 children (258 eyes), 12 months in 110 children (220 eyes) and 24 months in 47 children (94 eyes) from the beginning of Stellest™ wearing. Results In the first 6 months, stabilization of refraction was achieved in 82 % of patients (212 eyes), and in 14 % of patients (36 eyes) a hyperopic shift of refraction within +0.5 D was revealed. During 12 months of follow-up, stable cycloplegic refraction was detected in 80 % of cases (178 eyes). A hyperopic shift of refraction within +0.5 D and myopia progression up to –0.75 D were equally common: in 10 % of patients (21 eye in each group). During 2 years of follow-up, stable cycloplegic refraction was detected in 53 % of cases (50 eyes). A hyperopic shift of refraction within +0.5–0,75 D was noted in 17 % of patients. In some children myopia progressed, but the rate of progression decreased by 2 times or more. Thus, myopia progression by 0.25 D over 2 years of follow-up was detected in 14 % of patients (14 eyes), by 0.5 D – in 6 % (6 eyes) and by 1.25–1.5 D – in 10 % of patients (10 eyes). Mean initial axial length (AL) of the eyes was 24.5±0.1 mm. For the first 6 months, AL increase did not exceed 0.02±0.01 mm, for 12 and 24 months – 0.1±0.02 mm. Conclusions. Spectacle lenses with highly aspherical lenslets (HAL) effectively slow down myopia progression and axial elongation of the eyeball. Stabilization of refraction within 24 months was achieved in 70 % of patients. Accommodation has improved in all patients. Key words: myopia progression in children; peripheral myopic defocus; lenses with highly aspherical lenslets; Stellest™.

An Enhanced Modeling Framework for Bearing Fault Simulation and Machine Learning-based Identification with Bayesian-optimized Hyperparameter Tuning

Abstract Condition monitoring of rotating machinery offers a salient tool for predictive maintenance on rolling elements, subjected to continuous working loads, wear, fatigue, and degradation. In this study, an enhanced computational tool for bearing fault simulation and feature extraction is proposed. A subsequent identification scheme is realized, through Bayesian optimization of hyperparameters, including support vector classifier (SVC), gradient boosting (GBoost), random forest (RF), extreme gradient boosting (XBoost), light gradient boosting machine (LightGBM), and categorical boosting (CatBoost). The proposed hyperparameter optimization technique stands out from traditional methods by offering a more informed and efficient pathway to optimal performance in predictive maintenance. Utilizing Bayesian optimization for hyperparameter tuning of machine learning models, which has not been extensively explored in this field, our approach demonstrates significant advancements. Typical instances of bearing faults, like inner race, outer race, and ball faults are considered. The analysis relies on extraction of statistical and engineering features form collected response signals, including kurtosis, root mean square, peak, and ridge factor. Highly influential variables are highlighted based on feature selection and importance algorithms, allowing bearing fault classification. We demonstrate that SVC and LightGBM produce over 97% of accuracy at low computational cost. This approach constitutes a scalable and robust framework for similar applications in engineering diagnostics.

Assessing the Acceptability and Effectiveness of a Novel Therapeutic Footwear in Reducing Foot Pain and Improving Function among Older Adults: A Crossover Randomized Controlled Trial

Introduction: Nearly, a quarter of older adults suffer from frequent foot pain, impacting their quality of life. While proper footwear can alleviate this, design issues often hinder regular use. This study evaluated novel therapeutic footwear, designed for aesthetics and custom fit, to reduce foot pain. We hypothesized that older adults would experience less foot pain and favor the new footwear over their own. Methods: This 12-week crossover randomized controlled trial evaluated the effectiveness of OrthoFeet therapeutic footwear on reducing foot pain in older adults (n = 50, age = 65 ± 5, 18% male) with moderate to severe pain. Participants were assigned to either the AB or BA sequence. In AB, they wore OrthoFeet shoes for 6 weeks and then their own shoes for another 6 weeks; BA followed the reverse order. Pain and function were measured using the Foot Function Index. Acceptability was assessed through a technology acceptance model (TAM) questionnaire. Data collected at baseline, six, and 12 weeks were analyzed using t tests, χ2 tests, and generalized linear model. Results: Compared to participants’ own shoes, OrthoFeet shoes significantly reduced foot pain and disability. Notable improvements were observed in “foot pain at its worst,” “foot pain at the end of the day,” “overall pain score,” and “overall Foot Function Index score,” all showing statistically significant reductions (p < 0.050). Participants reported high adherence to wearing the OrthoFeet shoes, averaging 8 h per day and 5.8 days per week. TAM scores favored OrthoFeet shoes over participants’ own shoes in terms of ease of use, perceived benefit, and intention to recommend. Significant differences were noted in components representing perceived joint pain relief (p < 0.001, χ2 = 21.228) and the intention of use as determined by the likelihood of recommending the shoes to a friend with a similar condition (p < 0.001, χ2 = 29.465). Additionally, a majority of participants valued the appearance of the shoes, with 66% prioritizing shoe appearance and 96% finding the study shoes more stylish than their previous ones. Conclusion: This study underscores the significance of design and custom fit in promoting continuous wear for effective foot pain reduction in older adults. More research is needed on the intervention’s long-term impacts.

Metabolomics in Osteoarthritis Knee: A Systematic Review of Literature.

Osteoarthritis (OA) is a common degenerative disorder of the synovial joints and is usually an age-related disease that occurs due to continuous wear and tear of the cartilage in the joints. Presently, there is no proven medical management to halt the progression of the disease in the early stages. The purpose of our systematic review is to analyze the possible metabolites and metabolic pathways that are specifically involved in OA pathogenesis and early treatment of the disease. The articles were collected from PubMed, Cochrane, Google Scholar, Embase, and Scopus databases. "Knee", "Osteoarthritis", "Proteomics", "Lipidomics", "Metabolomics", "Metabolic Methods", and metabolic* were employed for finding the articles. Only original articles with human or animal OA models with healthy controls were included. From the initial screening, a total of 458 articles were identified from the 5 research databases. From these, 297 articles were selected in the end for screening, of which 53 papers were selected for full-text screening. Finally, 50 articles were taken for the review based on body fluid: 6 urine studies, 15 plasma studies, 16 synovial fluid studies, 11 serum studies, 4 joint tissue studies, and 1 fecal study. Many metabolites were found to be elevated in OA. Some of these metabolites can be used to stage the OA Three pathways that were found to be commonly involved are the TCA cycle, the glycolytic pathway, and the lipid metabolism. All these studies showed a vast array of metabolites and metabolic pathways associated with OA. Metabolites like lysophospholipids, phospholipids, arginine, BCCA, and histidine were identified as potential biomarkers of OA but a definite association was not identified, Three pathways (glycolytic pathway, TCA cycle, and lipid metabolic pathways) have been found as highly significant in OA pathogenesis. These metabolic pathways could provide novel therapeutic targets for the prevention and progression of the disease. The online version contains supplementary material available at 10.1007/s43465-024-01169-5.

High-Temperature and High-Pressure Tribological Properties of Siliconized Graphite for Water-Lubricated Thrust Bearing Application in Main Coolant Pump

The effect of the microstructure of siliconized graphite on tribological properties is investigated by using a high-temperature and high-pressure water-lubricated tribometer on a self-mated ring-on-ring configuration under an applied load of 500–1500 N with a spindle speed of 100–5000 rpm in both 90 °C (5 MPa) and 25 °C (1 MPa) water environments, respectively. The Stribeck curves measurement and continuous wear tests are performed and analyzed in both water environments. The wear behaviors of the graphite, SiC, and free-silicon phases in siliconized graphite are demonstrated to explore the wear mechanism. The larger wear depths of a low-worn surface roughness on the three phases contribute to the boundary lubrication. The shallower wear depths are observed on the SiC and Si phases under the mixed lubrication, corresponding to partial contact wear of surface asperities. The wavy surface of the SiC phase and uniform flow-oriented striae of the Si phase are attributed to hydrodynamic lubrication, caused by full water film scouring the worn surface. Finally, an integrated evaluation method of G duty parameters is successfully used to identify the lubrication regimes of siliconized graphite from the boundary, mixed, to hydrodynamic lubrications for a water-lubricated thrust bearing application in the main coolant pump of a nuclear power plant.

Understanding DLC system failure influenced by progressed wear

Diamond-like carbon (DLC) coatings are among the toughest and most effective measures for preventing wear on critical surfaces. Due to its high wear resistance, the deterioration of the protective coating only occurs upon failure. Understanding the events leading to failure and identifying a mild-abrasive wear process is crucial for sustainable application. We implemented a ‘Wöhler-like’ test matrix on a tribometer with oscillating tribocontact, employing radioactive isotopes for continuous wear measurements. This method allows to analyse the relationship between load and cycling or test time. When combined with friction coefficient changes, it enables the distinction between mild and severe wear, ultimately pinpointing the point of DLC deterioration. This approach was employed to compare different diesel lubricants, and its effectiveness was demonstrated. The relationship between loading condition and remaining DLC thickness illustrates that mild-abrasive wear is the critical factor for DLC lifetime, ultimately leading to coating system failure.

A Systematic Review of Denture Stomatitis: Predisposing Factors, Clinical Features, Etiology, and Global Candida spp. Distribution.

Denture stomatitis (DS) is a very common disease in wearers of removable complete and partial dentures with a worldwide prevalence in the range of 20-67%. Both industrially developed and impoverished nations are affected by the illness. DS is often associated with ill-fitting dentures or a fungal infection with Candida spp. Candida is normally found in the oral cavity microbiota, but it can be harmful to the health of elderly people with underlying diseases. Therefore, the purpose of the present study is to offer the most recent information about the epidemiology, etiology, and global distribution of Candida species associated with DS through a systematic review. Several databases, including Medline, Web of Science, and Scopus, were used to conduct an extensive search of the literature published in the previous 20 years. The selection of studies was performed by two authors. The extracted data were as follows: author, year of publication, country, sample, frequency of DS, method of diagnosing stomatitis, species of Candida, risk factors, and etiology of the disease. The JBI Critical appraisal tools were used to assess the quality of the studies. Eventually, twenty-eight studies were included in the systematic review. Twenty-one studies investigated DS, while seven studies examined Candida colonization in patients using removable dentures. The results show that the main causes of DS include the type of dentures, continuous wearing of dentures, and the formation of a Candida biofilm, which is facilitated by poor dental hygiene. Additionally, previous studies have pinpointed the significance of the salivary flow, saliva composition, and salivary pH. The findings of the current review indicate that it is crucial to monitor denture wearers for the appearance of DS, especially the patients whose immunity has been impaired due to a systemic condition. Finally, frequent follow-ups should include a clinical examination and microbial swabs of the palatal mucosa and the mucosal surface of the denture.

Using Discrete Element Method to Analyse the Drop Ball Test

The drop ball test (DBT) is a common quality control procedure used in many grinding media manufacturing units to evaluate the quality of manufactured balls. Whilst DBTs have provided reasonable data over many years, the quantitative comparison of the energy that the balls are subjected to during the DBT and in high-impact loading environments such as semi-autogenous grinding (SAG) mills remains a grey area. To that end, DBT experiments were conducted, and the discrete element method (DEM) was used to assess the grinding media collision behaviour and the extent of ball impact loading to determine the impact energy spectra of the ball collisions. The impact energy spectra data obtained were used to quantify the energy that the grinding balls are exposed to in the DBT environment. The results showed that larger balls were exposed to relatively higher energy levels and had a higher probability of fracture than smaller balls. Furthermore, early ball breakage in a grinding environment is mostly attributed to the existence of imperfections or pre-existing defaults within the ball, whilst continuous wear is a gradual consequence that deplete balls in the mill.

Using a standalone ear-EEG device for focal-onset seizure detection

BackgroundSeizure detection is challenging outside the clinical environment due to the lack of comfortable, reliable, and practical long-term neurophysiological monitoring devices. We developed a novel, discreet, unobstructive in-ear sensing system that enables long-term electroencephalography (EEG) recording. This is the first study we are aware of that systematically compares the seizure detection utility of in-ear EEG with that of simultaneously recorded intracranial EEG. In addition, we present a similar comparison between simultaneously recorded in-ear EEG and scalp EEG.MethodsIn this foundational research, we conducted a clinical feasibility study and validated the ability of the ear-EEG system to capture focal-onset seizures against 1255 hrs of simultaneous ear-EEG data along with scalp or intracranial EEG in 20 patients with refractory focal epilepsy (11 with scalp EEG, 8 with intracranial EEG, and 1 with both).ResultsIn a blinded, independent review of the ear-EEG signals, two epileptologists were able to detect 86.4% of the seizures that were subsequently identified using the clinical gold standard EEG modalities, with a false detection rate of 0.1 per day, well below what has been reported for ambulatory monitoring. The few seizures not detected on the ear-EEG signals emanated from deep within the mesial temporal lobe or extra-temporally and remained very focal, without significant propagation. Following multiple sessions of recording for a median continuous wear time of 13 hrs, patients reported a high degree of tolerance for the device, with only minor adverse events reported by the scalp EEG cohort.ConclusionsThese preliminary results demonstrate the potential of using ear-EEG to enable routine collection of complementary, prolonged, and remote neurophysiological evidence, which may permit real-time detection of paroxysmal events such as seizures and epileptiform discharges. This study suggests that the ear-EEG device may assist clinicians in making an epilepsy diagnosis, assessing treatment efficacy, and optimizing medication titration.