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Nanolubricants have attracted great interest due to the promise of friction and wear reduction by introducing nanoparticles. To date, the foremost challenge for developing a new nanolubricant is particle suspension. To understand the mechanisms of nanoparticle dispersion and identify bottlenecks, we conducted a comprehensive review of published literature and carried out an analysis of dispersion based on available data from the past 20 years. This research has led to three findings. First, there are two primary methods in dispersion: formulation with dispersant and surface modification. Second, surfactant and alkoxysilanes are primary chemical groups used for surface modification. Third, functionalization using surfactant is found to be suitable for nanoparticles smaller than 50 nm. For larger particles (>50 nm), alkoxysilanes are the best. The existence of a critical size has not been previously known. To better understand these three findings, we conducted an analysis using a numerical calculation based on colloidal theory. It revealed that a minimal thickness of the grafted layer in surfactant-modified nanoparticles was responsible for suspending small nanoparticles. For larger nanoparticles (>50 nm), they were suitable for silanization of alkoxysilane due to increased grafting density. This research provides new understanding and guidelines to disperse nanoparticle in a lubricating oil.

Lubricants have played important roles in friction and wear reduction and increasing efficiency of mechanical systems. To optimize tribological performance, chemical reactions between a lubricant and a substrate must be designed strategically. Tribochemical reactions are chemical reactions enabled or accelerated by mechanical stimuli. Tribochemically activated lubricant additives play important roles in these reactions. In this review, current understanding in mechanisms of chemical reactions under shear has been discussed. Additives such as oil-soluble organics, ionic liquids (ILs), and nanoparticles (NPs) were analyzed in relation to the tribochemical reaction routes with elements in metallic substrates. The results indicated that phosphorus, sulfur, fluorine, and nitrogen are key elements for tribochemical reactions. The resulting tribofilms from zinc dithiophosphates (ZDDP) and molybdenum dithiocarbamate (MoDTC) have been widely reported, yet that from ILs and NPs need to investigate further. This review serves as a reference for researchers to design and optimize new lubricants.

This study aimed to validate a handheld capillary blood lactate analyzer (Lactate Express) against a reference (EKF Biosen C-Line) and assess its impact on lactate thresholds. Thirty-five participants completed incremental running or cycling tests with capillary sampling. Lactate was measured with the Lactate Express and an EKF Biosen C-Line analyzer, yielding 231 paired samples (0.5-14.2 mmol l-1). Agreement was evaluated using intraclass correlation, Lin's concordance correlation, mean absolute error, and Bland-Altman analyses overall and within <1, 1-4, and >4 mmol l-1. Thresholds at 2 and 4 mmol l-1 were compared between devices for 18 participants in both exercise modes. Overall agreement was high (intraclass correlation coefficient 0.98), but Bland-Altman analysis showed a bias of -0.29 mmol l-1 with concentration dependent behavior. Bias was negligible within the 1-4 mmol l-1 range (-0.05 mmol l-1), positive at concentrations <1 mmol l-1 (0.29 mmol l-1) with pronounced underestimation at concentrations >4 mmol l-1 (-1.03 mmol l-1). Differences in 2 and 4 mmol l-1 thresholds were small and non-systematic. The Lactate Express demonstrates good relative and absolute agreement within the 1-4 mmol l-1 range relevant for threshold-based training prescription, but exhibits substantial and systematic bias at both low and high lactate concentrations. The device may provide broadly comparable threshold estimates in some cases but should not be considered interchangeable with the laboratory reference device across the full lactate concentration spectrum.

In this research, a novel flash heating coating application technique was utilized to create Ni-SiC coatings on carbon steel substrates with SiC contents much higher than is achievable using certain conventional coating techniques. Hardness profiles showed that the coatings improved the substrate by as much as 121%, without affecting the substrate. Tribotests showed that the wear performance was improved by as much as 4.7× in terms of the wear rate (mm3/N·m) for the same coating when using an Al2O3 counterpart. Pure SiC coatings as a reference were also fabricated. However, the SiC coatings experienced elemental diffusion of Fe from the carbon steel substrate into the coating during fabrication. This occurred due to the increased heat input required for pure SiC to fuse to the substrate compared to the Ni-SiC coatings and resulted in decreased tribological performance. Diffusion of Fe into the coating weakened the coating’s hardness and reduced the resistance to wear. It was concluded that ceramic–metallic composite coatings can successfully be fabricated utilizing this novel flash heating technique to improve the wear resistance of ceramic counterparts.

Due to its accelerated, uncontrollable, and unpredictable nature, pitting is one of the most common failure modes in pipelines used for oil and gas exploration. A comprehensive understanding of the mechanisms of pitting under conditions involving both abrasion and corrosion is currently lacking. This research investigated the effects of mechanical rubbing on the development of pitting of a widely used Type 2205 duplex stainless steel. Tribocorrosion experiments were conducted under mildly abrasive conditions where there is pitting but no significant material loss. Results showed that passivation was accelerated by rubbing, even though pitting was simultaneously formed. The length-to-width aspect ratio of the pits increased exponentially when the normal load during corrosive wear tests was increased. This phenomenon could lead to catastrophic failure in industrial applications such as underground and deep ocean pipes in the oil and gas industry.

Key message Transcervical radiofrequency ablation is a low-risk, uterus-preserving option for symptomatic fibroids in women with obesity with significant improvement of bleeding disorder, including ≥ 40 kg/m 2 . Obesity should not preclude offering TFA. Objective To evaluate the safety and effectiveness of transcervical radiofrequency ablation (TFA) for uterine fibroids in women with obesity. Methods Retrospective multicenter cohort at two German Fibroid Centers. From 574 consecutive TFA cases, we included patients with BMI ≥ 30 kg/m 2 and ≥ 6-month follow-up; those with incomplete data were excluded. Fibroids were characterized by ultrasound. TFA (Sonata®) was performed per instructions for use. Outcomes were perioperative complications and patient-reported improvement in abnormal uterine bleeding (AUB). Results Sixty patients were analyzed (age 43.59 ± 6.52 years; BMI 35.72 ± 6.72 kg/m 2 ). Mean operative and ablation times were 33.65 and 9.91 min, respectively. One intraoperative bleeding event (1.7%) was controlled with a balloon catheter; no postoperative complications occurred. Mean follow-up was 17.08 months (6–54). Overall, 42/60 (70.0%) reported AUB improvement. By BMI category: 30–34.9 kg/m 2 25/39 (64.1%), 35–39.9 kg/m 2 5/7 (71.4%), ≥ 40 kg/m 2 12/14 (85.7%) (p = 0.3168). Considering the initial assessment, 48/60 (80.0%) improved; six later recurred, yielding 42/60 (70.0%) at last follow-up. Conclusion TFA showed a very low complication rate and clinically meaningful bleeding improvement in women with obesity, with comparable outcomes across BMI strata, including ≥ 40 kg/m 2 . Obesity is not a barrier to safe, effective TFA. Prospective, BMI-stratified studies with validated bleeding measures and objective endpoints are warranted.

Deposition of a coating on rough surfaces faces unique challenges due to the complexity of substrate morphology. In the present research, electroless deposition of a Ni-P coating was successfully deposited on diamond particles. Microtomography was conducted to study the deposition mechanisms. It revealed that the coating coverage rate on diamond particles was affected by the synergistic action of the deposition time, substrate morphology, and hypophosphite concentration. The best coverage was achieved in a solution with 0.2 mol/L hypophosphite. Two major morphological features of the coating: nodular and smooth, were influenced by the deposition parameters, coating integrity, and substrate morphology. The failure was seen in fractured and peeled off coatings. It was due to residual stress produced by the coalescing of crystallites during the deposition. This failure mechanism explains the tendency of coating fracture at three morphological features of the substrate. This work is beneficial to semiconductor manufacturing where effective cutting in chip fabrication is essential.

Designing modern antenna structures is a challenging endeavor. It is laborious and heavily reliant on engineering insight and experience, especially at the initial stages oriented towards the development of a suitable antenna architecture. Due to its interactive nature and hands-on procedures (mainly parametric studies) for validating the suitability of particular geometric setups, typical antenna development requires many weeks and significant involvement of a human expert. The same reasons only allow the designer to try out a very limited number of options in terms of antenna geometry arrangements. Automated topology development and dimension sizing is therefore of high interest, especially from an industry perspective where time-to-market and expert-related expenses are of paramount importance. This paper discusses a novel approach to unsupervised specification-driven design of planar antennas. The presented methodology capitalizes on a flexible and scalable antenna parameterization, which enables the realization of complex geometries while maintaining reasonably small parameter space dimensionality. A customized nature-inspired algorithm is employed to carry out space exploration and identification of a quasi-optimum antenna topology in a global sense. A fast gradient-based procedure is then incorporated to fine-tune antenna dimensions. The design framework works entirely in a black-box fashion with the only input being design specifications, and optional constraints, e.g., concerning the structure size. Numerous illustration case studies demonstrate the capability of the presented technique to generate unconventional antenna topologies of satisfactory performance using reasonable computational budgets, and with no human expert interaction necessary whatsoever.

Internet of things (IoT) devices are exponentially growing in adoption across multiple industries. While IoT devices control critical components of daily life, many still lack basic security protections. This research paper surveys the scientific and trade literature on the regulatory and security considerations for IoT device implementors that broker personal data. The General Data Protection Regulation (GDPR), Health Insurance Portability and Accountability Act (HIPAA), and California Consumer Privacy Act (CCPA) provide regulatory mandates for personal data. IoT device implementors that interact with personal data must safeguard the data or face the consequences, including fines and potential jail time. IoT devices remain a tempting target for adversaries due to weaknesses in their architecture and design. IoT implementors must reconsider traditional methods to protect IoT devices, including network segmentation and virtual private networks, as identity is the new perimeter. Innovation is outpacing regulatory mandates as global position system (GPS) sensors add location into IoT data streams and big data to reconstruct anonymized data back to a person. IoT implementers are challenged by inconsistency across economic areas about the definition of personal data. This paper proposed basic IoT security architecture guidelines that help IoT implementors broker personal data to remain compliant with regulatory mandates and keep the device secure.

High-performance anti-friction coatings are applicable for various applications. The main complications in fabricating such coatings are acquiring desired properties such as low coefficient of friction and high wear resistance while maintaining structural integrity and cohesion. Most state-of-the-art commercial coatings cannot endure severe conditions for extended periods resulting in stunted efficiency and an unsafe environment. In this work, we designed high-performance anti-friction coatings which incorporate ingredients that display robustness and high structural cohesion. An effective and economical method was established that could synthesize the coating consisting of high-temperature ceramics such as BN and SiC; friction modifiers were hybridizing graphite and α-zirconium phosphate. The analysis showed that the coatings exhibited exceptional lubrication performance at room temperature. The coating was annealed at 300 °C and was stable under a wide temperature range of 37-300 °C. The lowest average coefficients of friction for our coated steel sample were 0.107 and 0.169 in air and seawater, respectively. Compared to the coefficient of friction values of a blank non-coated steel sample, reductions of 76.22% in air and 45.48% in seawater percentages were achieved. This work will advance future coating designs with enhanced properties for a wide range of tribological applications including anti-friction coating applications.