Search Results (1,926)

This paper proposes a new accelerated fixed-point algorithm based on a double-inertial extrapolation technique for solving structured variational inclusion and convex bilevel optimization problems. The underlying framework leverages fixed-point theory and operator splitting methods to address inclusion problems of the form $0\in (A+B)\left(x\right)$, where A is a cocoercive operator and B is a maximally monotone operator defined on a real Hilbert space. The algorithm incorporates two inertial terms and a relaxation step via a contractive mapping, resulting in improved convergence properties and numerical stability. Under mild conditions of step sizes and inertial parameters, we establish strong convergence of the proposed algorithm to a point in the solution set that satisfies a variational inequality with respect to a contractive mapping. Beyond theoretical development, we demonstrate the practical effectiveness of the proposed algorithm by applying it to data classification tasks using Deep Extreme Learning Machines (DELMs). In particular, the training processes of Two-Hidden-Layer ELM (TELM) models is reformulated as convex regularized optimization problems, enabling robust learning without requiring direct matrix inversions. Experimental results on benchmark and real-world medical datasets, including breast cancer and hypertension prediction, confirm the superior performance of our approach in terms of evaluation metrics and convergence. This work unifies and extends existing inertial-type forward–backward schemes, offering a versatile and theoretically grounded optimization tool for both fundamental research and practical applications in machine learning and data science. Full article

During the annealing, recrystallization processes in ceramics can occur, manifested in the formation of new grains, grain-boundary migration, and grain coarsening. It was expected that recrystallization in mechanically deformed zones, which contain residual stresses and high defect densities, will proceed in a different way compared to the surrounding, relaxed material. Characterizing these spatial variations in defect evolution, phase transformations, and microstructural recovery is essential for predicting performance and avoiding critical structural changes when designing zirconia-based ceramics for high-temperature, load-bearing applications. To study these effects, we used partially stabilized Ce-doped ZrO₂ ceramics, fabricated by solid-state synthesis. Phase composition, structural features, and morphology of these ceramics were studied using Raman spectroscopy, XRD and SEM before and after annealing in the mechanically stressed and relaxed regions. In mechanically deformed regions a more pronounced phase transformation from monoclinic to tetragonal was observed compared to relaxed zones. This result indicates that strain can facilitate tetragonal phase formation in zirconia ceramics when the material is subjected to elevated temperatures. Mechanical stresses should be taken into account when fabricating ceramic components, as they can induce phase transformation during heat treatments and change the properties of ceramics significantly. Full article

To address the issue of missing constraints on control variables in the trajectory optimization problem of the differential dynamic programming (DDP) method, the adaptive projection differential dynamic programming (AP-DDP) method is proposed. The core of the AP-DDP method is to introduce adaptive relaxation coefficients to dynamically adjust the smoothness of the projection function and to effectively solve the gradient disappearance problem that may occur when the control variable is close to the constraint boundary. Additionally, the iterative strategy of the relaxation coefficient accelerates the search for a feasible solution in the initial stage, thereby improving the algorithm’s efficiency. When applied to three trajectory optimization problems, compared with similar truncated DDP, projected DDP, and Box-DDP methods, the AP-DDP method found the optimal solution in the shortest computation time, thereby proving the efficiency of the proposed algorithm. While ensuring the iterative process reaches the global optimum, the computing time of the AP-DDP method was reduced by 32.8%, 13.3%, and 18.5%, respectively, in the three examples. Full article

Conductive composites are a flexible class of engineered materials that combine conductive fillers with an insulating matrix—usually made of ceramic, polymeric, or a hybrid material—to customize a system’s electrical performance. By providing tunable electrical properties in addition to benefits like low density, mechanical flexibility, and processability, these materials are intended to fill the gap between conventional insulators and conductors. The increasing need for advanced technologies, such as energy storage devices, sensors, flexible electronics, and biomedical interfaces, has significantly accelerated their development. The electrical characteristics of composite materials, including metallic, ceramic, polymeric, and nanostructured systems, are thoroughly examined in this review. The impact of various reinforcement phases—such as ceramic fillers, carbon-based nanomaterials, and metallic nanoparticles—on the electrical conductivity and dielectric behavior of composites is highlighted. In addition to conduction models like correlated barrier hopping and Debye relaxation, the study investigates mechanisms like percolation thresholds, interfacial polarization, and electron/hole mobility. Because of the creation of conductive pathways and improved charge transport, developments in nanocomposite engineering, especially with regard to graphene derivatives and silver nanoparticles, have shown notable improvements in electrical performance. This work covers the theoretical underpinnings and physical principles of conductivity and permittivity in composites, as well as experimental approaches, characterization methods (such as SEM, AFM, and impedance spectroscopy), and real-world applications in fields like biomedical devices, sensors, energy storage, and electronics. This review provides important insights for researchers who want to create and modify multifunctional composite materials with improved electrical properties by bridging basic theory with technological applications. Full article

Free radicals in G-361 human melanoma malignum control cells and the cells cultured with simvastatin were examined by EPR spectroscopy. The proliferation of the cells was determined. The aim of this work was to examine the influence of simvastatin used at different concentrations in the G-361 cell culture on its free radicals. The concentrations of simvastatin—0.1 μM, 1 μM, 3 μM, and 5 μM—were tested. EPR spectra of free radicals were measured by an X-band (9.3 GHz) spectrometer. Amplitudes, integral intensities, linewidths, and g factors were determined. Melanin biopolymers are the main source of o-semiquinone free radicals in G-361 human melanoma malignum cells, for which the EPR lines show characteristic g values of 2.0046–2.0059, but also, free radicals occurring in other cellular structures may contribute to these signals. The amount of free radicals decreases after interactions of simvastatin with the G-361 cells, and this effect depends on the concentration of simvastatin. The highest amounts of free radicals exist in G-361 cells cultured with simvastatin at concentrations of 3 μM and 5 μM. The relatively lower amounts of free radicals occur in G-361 cells cultured with simvastatin at concentrations of 0.1 μM and 1 μM. The fast spin–lattice relaxation processes exist in the control G-361 cells and in the cells cultured with simvastatin, regardless of simvastatin concentration. Full article

Background: Anxiety and stress are common mental health issues that affect both psychological and physiological well-being as well as quality of life. The Tibetan Singing Bowl, which combines sound and vibration, is often used in meditation and relaxation and may offer therapeutic benefits. However, current research findings are scattered and lack systematic integration and quantitative validation. Methods: This study is a systematic review that included 14 quantitative studies from the past 16 years investigating the effects of Tibetan Singing Bowl interventions on adult psychological and physiological health. Data were sourced from six major databases and supplemented through citation tracking. Inclusion criteria were adults aged 18 and over, with interventions primarily involving Tibetan Singing Bowls, and reporting quantitative outcomes related to psychological indicators (e.g., anxiety and depressive symptoms) and physiological indicators (e.g., Heart Rate Variability and brainwave activity). Study quality was assessed using Joanna Briggs Institute (JBI) criteria, and findings were synthesized narratively to identify patterns and trends. Results: Study populations included general adults, individuals with emotional distress, and patients with cancer or chronic illnesses. Interventions ranged from single sessions to multiple courses, with some incorporating breathing or other practices. Most studies reported significant reductions in anxiety and depressive symptoms, improvements in well-being and quality of life, increases in Heart Rate Variability, and decreases in heart rate. Some studies also found increased Delta and Theta brainwave activity. Due to heterogeneity in study design and limited articles, no meta-analysis was conducted. Conclusions: Tibetan Singing Bowl interventions demonstrate potential for stress reduction and psychological well-being, offering a non-invasive, low-risk, and widely accepted complementary method supporting therapeutic processes, which can be suitable for clinical and community settings. Future research should focus on rigorously designed controlled trials and consider follow-up assessments to more accurately evaluate the effectiveness of TSB interventions. Full article

The interaction between carbon nanoparticles (CNs) and Langmuir monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) as a model pulmonary surfactant (PS) film was studied to shed light on the physicochemical bases underlying the potential adverse effects associated with pollutant inhalation. The results indicated that the surface pressure–area isotherms of the DPPC monolayers shifted toward lower molecular areas, and the compression modulus was reduced in the presence of CNs, hindering the ability of the DPPC monolayers to reduce the surface tension. The relaxation process of the DPPC monolayers were influenced, and the surface morphology and the continuity of the monolayers were destroyed by the penetration of CNs into the DPPC monolayers. The molecular dynamics simulation revealed that particle incorporation into the DPPC monolayers reduced the packing density of the DPPC molecules, worsening the mechanical performance of the monolayers. This effect was attributed to the strong binding trend between the CNs and the DPPC molecules. These results demonstrated that CNs could alter the relaxation mechanisms of the PS film, and this may cause a modification of the inhaled particle transport at the PS film and contribute to adverse health effects in the respiratory system of workers involved in the CN production process. Full article

This article investigates the formation of solidification cracks in steel forgings used for bearing rings in gear reducers of robotic arms. The forging and heat treatment processes, conducted under consistent technological conditions, revealed the occurrence of high-temperature annealing cracks caused by plasticity depletion during stress relaxation. Additionally, solidification cracks were analyzed, with chemical compositions and hardness measurements indicating susceptibility due to elevated carbon and chromium content, as well as a high cracking parameter. Die tool wear and damage during forging were identified as key contributors to crack formation, transferring surface defects, inclusions, and creating cracks that propagate during subsequent processing. The findings underscore the influence of the tooling conditions, material properties, and process parameters on the quality and reliability of steel forgings. Full article

This study examines the mediating role of recovery experiences in the relationship between work–family conflict (WFC) and employee well-being. While WFC has been consistently linked to negative outcomes such as psychological distress and reduced life satisfaction, the mechanisms that may buffer its effects remain underexplored. Drawing on the Conservation of Resources Theory and the Effort-Recovery Model, we investigated whether four types of recovery experiences—psychological detachment, relaxation, mastery, and control—mediate the WFC–well-being relationship. A cross-sectional survey was conducted with 240 employees using validated self-report instruments. Data were analysed through correlation, regression, and mediation techniques, including bootstrapping procedures via PROCESS. The results confirmed a significant negative association between WFC and well-being. All four recovery experiences were positively related to well-being, with relaxation emerging as the strongest predictor. Mediation analyses showed that each of the recovery experiences partially mediated the relationship between WFC and well-being. These findings highlight the importance of recovery as a psychological buffer in the context of elevated work–family interference. Organizational practices that foster recovery—such as encouraging psychological detachment, offering flexible schedules, and promoting restorative activities—may contribute to sustaining employee mental health and resilience. Full article

This study aims to explore the influence mechanism of wet fermented soybean dregs on corn stover formation, improve the forming quality of straws and reduce the power demand and specific energy consumption of forming equipment. This study takes 2 mm and 4 mm corn stover sizes as the objects and explores the influence of different amounts of fermented soybean dregs on the volume relaxation ratio, maximum compressive force and specific energy consumption of straw forming pellets under compression displacements of 90 mm and 92 mm. Different amounts of water are selected according to the total moisture content of the mixed feed, and the effects of adding water and fermented wet soybean dregs on feed forming are compared and studied. The results indicate that, under certain conditions, adding water or wet fermented soybean dregs to straw is beneficial for shaping. Adding wet fermented soybean dregs to straw can improve the nutritional value of feed and promote the utilization of agricultural waste. Therefore, adding wet fermented soybean dregs is an effective method for processing high-quality feed pellets. Taking into account the quality and specific energy consumption of mixed feed processing, the optimal pelleting process for corn stover and wet fermented soybean dregs in a mixed feed is as follows: straw particle size of 4 mm, added mass ratio of wet fermented soybean dregs of 5% and compression displacement of 92 mm. These results support the research and development of technology and devices for high-quality and low-energy mixed formation using fermented soybean dregs and straw, and they offer a new route for the utilization of other high-moisture feeds. Full article

In this study, a series of copolymers was synthesized using the promising biodegradable polymers Poly(L-lactic acid) (PLLA), Poly(lactic-co-glycolic acid) (PLGA), and Poly(ethylene adipate) (PEAd), known for their high potential. PEAd was synthesized through a two-step melt polycondensation process and then used to prepare copolymers with PLLA (PLLA-co-PEAd) and PLGA (PLGA-co-PEAd) at weight ratios of 90/10 and 75/25, respectively. The synthesized materials, along with the starting polymers, were extensively characterized for their structure, molecular weight, crystallinity, and thermal behavior. These novel systems exhibit single thermal transitions, e.g., glass transition. The incorporation of PEAd into the copolymers induced a plasticizing effect, evidenced by a consistent decrease in the glass transition temperature. Due to the latter effect in combination with the M_w drop, the facilitation of crystal nucleation was observed. Finally, the results by dielectric spectroscopy on the local and segmental molecular mobility provided additional proof for the homogeneity of the systems, as manifested, e.g., by the recording of single segmental relaxation processes. Overall, the findings indicate that the PLLA-co-PEAd and PLGA-co-PEAd copolymers hold significant potential, and the use of complementary experimental techniques offers valuable insights and indirect indications of their properties. Full article

This paper deals with a standard cell-based analog-in-concept pW-power building block as a comparator and a wake-up oscillator. Both topologies, traditionally conceived as an analog building block made by a custom process and supply voltage-dependent design flow, are designed only by using digital gates, enabling them to be automated and fully synthesizable. This further results in supply voltage scalability and regulator-less operation, allowing direct powering by an energy harvester without additional ancillary circuit blocks (such as current and voltage sources). In particular, the circuit similarities in implementing a rail-to-rail dynamic voltage comparator and a relaxation oscillator using only digital gates are discussed. The building blocks previously reported in the literature by the author will be described, and the common root of their design will be highlighted. Full article

Background/Objectives: Improvements in depression and anxiety, associated with moderate increases in physical activity, might induce reductions in emotional eating, especially in women with obesity, where emotion-driven eating is highly problematic. This pilot, field-based study sought to assess whether physical activity increase, itself, primarily predicts improved mood (biochemical theories) or if psychosocial factors associated with cognitive–behavioral treatment are principal correlates (behavioral theories). An aim was to inform improved treatment processes. Methods: Women with obesity participated in 6-month community-based behavioral obesity treatments emphasizing either: (a) standard education in weight-reduction methods (n = 28), (b) eating-related self-regulation methods (n = 24), or (c) self-regulation + relaxation training (n = 24). They completed a series of behavioral and psychological self-reports at baseline and Months 3 and 6. Results: Findings confirmed no significant difference in 3-month increases in physical activity, by group. There were significantly greater overall improvements in depression, emotional eating, self-regulation, and self-efficacy across the two self-regulation-focused groups (ps < 0.02), with anxiety improvement not reaching significance (p = 0.055). Separate significant paths from 3-month changes in depression and anxiety → self-efficacy change → emotional eating change were found. The same significant path was detected emanating from 6-month anxiety change; however, the hypothesized path of 6-month changes in depression → self-regulation → self-efficacy → emotional eating was, rather, significant. Weight reduction was considerably greater in the two self-regulation-based groups (~6% reduction), with simultaneously entered changes in self-regulation and self-efficacy significant predictors of those weight changes. Conclusions: Findings suggested viability in behavioral theory-driven explanations of the physical activity-mood improvement relationship. Future treatment foci on self-regulatory skills development leading to improvements in eating-related self-efficacy, emotional eating, and weight were suggested to extend the findings of this pilot study. Full article

Relaxation behavior of water confined in reverse micelles under temperature-induced micelle clustering is undertaken using broadband dielectric spectroscopy in frequency range 1 Hz–20 GHz. All microemulsion systems with sufficiently noticeable micelle water pool (water/surfactant molar ratio W > 10) depict three relaxation processes, in low, high and microwave frequencies, anchoring with relaxation of shell (bound) water, orientation of surfactant anions at water-surfactant interface and relaxation of bulk water confined in reverse micelles. The analysis of dielectric relaxation processes in AOT-based w/o microemulsions under temperature induced clustering of reverse micelles were made according to structural information obtained in NMR and conductometry experiments. The “wait and switch” relaxation mechanism was applied for the explanation of results for water in the bound and bulk states under spatial limitation in reverse micelles. It was shown that surfactant layer predominantly influences the bound water. The properties of water close to AOT interface are determined by strong interactions between water and ionic AOT molecules, which perturb water H-bonding network. The decrease in micelle size causes a weakening of hydrogen bonds, deformation of its steric network and reduction in co-operative relaxation effects. Full article

In the process of evaluating the quality of a company’s development, the issues related to production capacity and environmental pollution have emerged as significant concerns. Drawing on the methodologies employed in previous related research, this study utilizes the Data Envelopment Analysis with relaxation variables and the Global Malmquist–Luenberger index to measure the green total factor productivity of Chinese heavy-polluting enterprises. The main findings of this study are as follows: (1) It is clearly demonstrated that higher managerial effectiveness has a substantial positive impact on the improvement of a company’s green total factor productivity; (2) the digitalization progress within enterprises serves as a moderating factor in the relationship between managerial effectiveness and green total factor productivity; (3) the extent of financial constraints acts as a mediating variable, intervening in the relationship between managerial efficiency and green total factor productivity; and (4) a threshold effect is detected between managerial effectiveness and the debt repayment pressure faced by enterprises. When the threshold values of managerial effectiveness or the quick ratio are surpassed, the influence of managerial effectiveness on the green total factor productivity of enterprises will undergo a change. Full article