Search Results (207)

The use of herbal medicines has gained popularity, both in science and among the public, as a natural alternative for the treatment of numerous diseases, including type 2 diabetes. Objective: The objective of this study was to evaluate peri-implant and long bone biomechanics in type 2 diabetic animals, treated or not with Bauhinia forficata. Methods: Thirty-two rats were allocated into four groups: normoglycemic (NG), normoglycemic + Bauhinia forficata (NGBf), type 2 diabetes (T2D), and T2D + Bauhinia forficata (T2DBf). Diabetes was induced using a cafeteria diet and streptozotocin (35 mg/kg). Bauhinia forficata tea (50 g/L) was administered to the NGBf and T2DBf groups. After 14 days, titanium implants were installed in the tibial metaphysis of all animals. Biomechanical analysis (removal torque), computerized microtomography, three-point bending test, confocal microscopy, and real-time PCR were performed. The results were tabulated, and a statistical test was conducted with a significance level of 5%. Results: Bauhinia forficata significantly improved the weight and blood glucose levels of the animals. In terms of biomechanics and the microarchitecture of long bones, T2D did not impair bone metabolism, and the use of the therapy did not cause significant changes in the parameters evaluated. However, T2D promoted significant impairment in the structural, biomechanical, and molecular characteristics of the peri-implant repair process, and the use of Bauhinia forficata increased the parameters evaluated in T2DBf. Conclusions: Type 2 diabetes mellitus significantly compromises peri-implant bone repair, with no influence on the metabolism of long bones, and Bauhinia forficata acts positively on both the etiopathogenesis of the disease and the tissue response to bone repair. Full article

Induction motors require effective speed controllers to handle challenging conditions such as indirect vector control, nonlinear dynamics, load-disturbances, and changes in rotor resistance. Although proportional–integral (PI) controllers and type-1 fuzzy logic controllers (T1-FLC) are relatively straightforward to implement, they can produce significant overshoot and slow recovery; type-2 fuzzy logic controllers (T2-FLC), on the other hand, improve uncertainty management at the cost of higher computational complexity. This study proposes a type-3 fuzzy logic controller (T3-FLC) that balances robustness with a single $\alpha$-slice using two inputs and seven membership functions per input (49 rules). In six comparison scenarios, the type-3 FLC (T3-FLC) consistently offers a lower overshoot percentage and shorter recovery/settling times than the PI controller and type-1 FLC (T1-FLC). Overshoot drops to $0.13\%$ with T3-FLC during a high-speed positive step, while this value for the PI controller is $4.43\%$. During a low-amplitude positive step, T3-FLC reaches $1.37\%$, while the PI controller reaches $11.12\%$ and T1-FLC reaches $4.13\%$. After load torque is removed, the recovery time $t_{\mathrm{rec}}$ under T3-FLC is $0.064$ s at high speed and $0.158$ s at low speed, while for PI, these values are $0.400$ s and $1.975$ s, respectively. Under variations in rotor resistance, T3-FLC maintains a significantly smaller overshoot value: with a $-20\%$ change (3–6 s window), the values are $1.45\%$ (T3-FLC) versus $9.59\%$ (PI) and $4.51\%$ (T1-FLC); with a $+20\%$ change (3–6 s), the values are $0.14\%$ (T3-FLC) versus $4.36\%$ (PI) and $0.15\%$ (T1-FLC). Although there are isolated cases in which PI or T1-FLC shows a marginal advantage in a single metric (e.g., slightly smaller overshoot during transition or lower peak error during disturbance), T3-FLC generally provides the best balance, combining low overshoot with short settling/recovery time while keeping steady-state error at zero in all scenarios. Full article

This study introduces a sensorless fault diagnosis method for efficiently detecting bearing faults in induction motors. The proposed method eliminates the need for torque sensors, frequency sensors, thermal cameras, or real-time Fast Fourier Transform (FFT) tools. Induction motors are commonly utilized in a variety of industrial applications, including fans, pumps, and home appliances, due to their straightforward construction, affordability, and robust reliability. Traditional bearing fault diagnosis methods often rely on additional hardware such as vibration or thermal sensors. Additionally, approaches employing Artificial Intelligence (AI) and real-time FFT processing require advanced and expensive hardware capabilities. However, many V/f control systems are primarily intended for cost-effective and simple implementations, making resource-intensive approaches undesirable. Therefore, such methods present limitations for these use cases. To address these challenges, this paper presents a sensorless detection technique that estimates torque via a flux observer, removing the dependence on external sensors. The estimated torque is processed using an offline FFT to identify amplitude changes within bearing fault frequency bands. Here, the FFT-based frequency analysis is performed offline and is used to design a targeted band-pass filter (BPF). The torque signal, after passing through the BPF, undergoes a straightforward threshold-based logic to assess the existence of faults. Compared to AI- or data-driven approaches, the proposed method provides a lightweight, interpretable, and sensorless solution without the need for additional training or high-end processors. Despite its straightforward approach, the technique achieves effective detection of bearing faults across various components and speeds, making it ideal for embedded and economically constrained motor applications. Full article

A state-of-the-art tunnel magnetoresistance (TMR) sensor architecture, which is based on the perpendicularly magnetized magnetic tunnel junction (pMTJ), is introduced and engineered for ultrafast, high thermal stability, and linearity for magnetic field detection. Limitations in high-frequency environments, stemming from insufficient thermal stability and slow recovery times in conventional TMR sensors, are overcome by this approach. The standard MRAM structure is modified, and the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction is employed to give a strong, internal restoring torque to the storage layer magnetization. Sensor linearity is also ensured by this RKKY mechanism, and rapid relaxation to the initial spin state is observed when an external field is removed. The structural and magnetic properties of the multilayer stack are experimentally demonstrated. Robust synthetic antiferromagnetic (SAF) coupling is confirmed by using polar MOKE spectroscopy with an optimal Ru insertion layer thickness (0.6 nm), which is essential for high thermal stability. Subsequently, an ultrafast response of this TMR sensor architecture is probed by micromagnetic simulations. The storage layer magnetization rapidly recovers to the SAF state within an ultrashort time of 5.78 to 5.99 ns. This sub-6 ns recovery time scale suggests potential operation into the hundreds of MHz range. Full article

The consequent-pole interior permanent-magnet (CPM) motor is a promising alternative for minimizing rare-earth magnet usage while supporting high-speed operation. However, rotor flux asymmetry often leads to distorted back-electromotive force waveforms and increased torque ripple. This study investigated a flared-type CPM motor that employs ferrite magnets arranged in a flared configuration to enhance flux concentration within a compact rotor. To address waveform distortion, structural modifications such as bridge removal and an asymmetric air-gap design were implemented. Three rotor parameters—polar angle, asymmetric air-gap length, and rotor opening length—were optimized using Latin hypercube sampling combined with an evolutionary algorithm. Finite element method analyses conducted under no-load and rated-load conditions showed that the optimized model achieved a 77.8% reduction in torque ripple, a 43.4% decrease in cogging torque, and a 0.5% improvement in efficiency compared with the basic model. Stress analyses were performed to examine the structural bonding strength and rotor deformation of the optimized model under high-speed operation. The results revealed a 5.5× safety margin at four times the rated speed. The proposed approach offers a cost-effective and sustainable alternative to rare-earth magnet machines for high-efficiency household appliances, where vibration reduction, cost stability, and energy efficiency are critical. Full article

Robot manipulators are suitable for many industrial tasks, such as assembly and pick-and-place operations. However, high-acceleration motions result in shaking forces and moments to the base, which can cause vibration of the manipulator and instability in the case of a mobile base. Furthermore, gravity compensation of the manipulator links requires additional motor torque, which can increase energy consumption. Balanced manipulators address these problems by employing a mechanical design that results in the balancing of gravity and other static forces, or the removal of shaking forces and/or moments. This review paper provides an overview of mechanical design approaches for balanced robotic manipulation, with an emphasis on experimentally prototyped designs. We first define the types of balancing according to the literature. We then provide an overview of different approaches to the mechanical design of balanced manipulators, along with simple examples of their implementation. Experimental prototypes in this field are then comprehensively presented and summarized to allow readers to compare their development maturity. At the end of the paper, we outline challenges and future directions of research. Full article

Background: Abutment screw loosening (ASL) is the most frequent mechanical complication in dentistry, leading to prosthetic instability and biological risks. Preload, generated during screw tightening, is critical for maintaining stability but is influenced by torque application, screw geometry, and cyclic loading. Methods: This in vitro study compared torque loss between two implant systems (Osstem TSIII and KSIII) with different abutment screw designs. Fifty implant–abutment assemblies (n = 5 per torque group) were tested under tightening torques of 20, 25, 30, 35, and 40 Ncm. Initial removal torque (T1) was measured 5 min after tightening, followed by cyclic loading (150 N, 14 Hz, 100,000 cycles). Post-fatigue removal torque (T2) was then recorded, and torque loss rate (%) was calculated. Independent t-tests and a one-way ANOVA were used for statistical analysis. Results: KSIII consistently exhibited higher T1 and T2 values than TSIII across all torque levels (p < 0.05). The torque loss rate for TSIII ranged from 36.5% (35 Ncm) to 51.8% (20 Ncm), showing a torque-dependent trend (p < 0.05). In contrast, KSIII maintained torque loss rates below 25% at all levels, with no significant differences between torque groups (p > 0.05). On average, torque loss in TSIII was approximately 2.5–3.0 times higher than in KSIII. Conclusions: The KSIII system demonstrated superior biomechanical stability, with significantly lower torque loss compared with TSIII, independent of torque level. Clinically, these findings suggest that the KSIII system may reduce the incidence of screw loosening and associated complications. A tightening torque of approximately 35 Ncm appeared to provide the most stable preload. Long-term in vivo studies are warranted to confirm these results under clinical conditions. Full article

Background: The morphology of implant threads plays a crucial role in achieving primary stability, which is essential for successful osseointegration and immediate loading of dental implants. This study aimed to evaluate how different implant thread pitches and an under-preparation drilling technique impact primary stability using an in vitro model. Methods: The study was conducted on low-density polyurethane bone models with and without cortical layers. The following three different implant thread profiles were tested: CYROTH 0.40 (0.40 mm), CYROTH 0.45 (0.45 mm), and CYROTH T (0.35 mm). Two different drilling procedures were utilized, with diameters of 3.4 mm and 3.7 mm, at a low rotational speed of 30 rpm. Primary stability was assessed by measuring insertion torque (IT), removal torque (RT), and resonance frequency analysis (RFA). Results: The low rotational speed of 30 rpm was found to be effective for achieving favorable fixation parameters in all scenarios. The 0.45 mm thread consistently exhibited higher implant stability quotient (ISQ) values (from two to six points higher) compared to the 0.40 mm and standard 0.35 mm threads, while also requiring lower IT. The highest ISQ values were recorded in the 20 pounds per cubic foot (PCF) block with a cortical layer using the 0.45 mm thread and a 3.4 mm drill. The under-preparation using the 3.4 mm drill resulted in higher IT and RT values than the 3.7 mm drill. Conclusions: This study demonstrated that implant thread pitch and drilling technique are critical factors influencing primary stability. Utilizing a wider thread pitch (0.45 mm) along with an under-preparation drilling protocol can significantly improve implant stability, even in low-density bone, without the need for excessive IT. These findings suggest that selecting the appropriate implant macrogeometry and surgical technique can optimize the primary stability of dental implants. Full article

The introduction of functional elements is essential for many industrial components which rely on elements such as bolts, screws, nuts, or clips that are integrated into the workpieces. In the field of cold joining technologies, double-sided self-pierce riveting (DS-SPR) presents itself as a proper alternative to produce the mechanical connection of those elements into sheet panels. For the purpose of this investigation, a tubular rivet with a machined thread to replicate a hollow bolt was joined to a sheet panel. Since this application will be subjected to torsion loads when a nut or other elements are fastened, tubular rivets with different numbers of semi-longitudinal rectangular openings at their ends (0, 2, 4, and 8) were investigated to identify the optimal design that ensures proper performance during its service life. The results show that rivets with four openings achieved a torsional resistance of more than 40 N·m, which is over double that of the original rivet without openings, while maintaining comparable shear strength (~10 kN). A functional hollow bolt with an outer thread was successfully produced, achieving a torque capacity of 35 N·m, equivalent to an M8 solid bolt, but with reduced weight. These findings highlight DS-SPR as a viable technology for manufacturing functional riveted elements that combine the permanent joints between sheets and removable connections with secondary components, offering both structural performance and lightweight advantages. Full article

This paper proposes a method to analyze the effect of the rotor’s harmonic winding design and the output of a brushless wound rotor synchronous machine (WRSM) for optimal excitation power transfer. In particular, the machine analyzed by the finite-element method was a 48-slot eight-pole 2D model. The subharmonic magnetomotive force was additionally created in the air gap flux, which induces voltage in the harmonic winding of the rotor. This voltage is rectified and fed to the field winding through a full bridge rectifier. Eventually, a direct current (DC) flows to the field winding, removing the need for external excitation through brushes and sliprings. The effect of the number of harmonic winding turns is analyzed and the field winding turns were varied with respect to the available rotor slot space. Optimization of the harmonic excitation part of the machine will maximize the rotor excitation for regulation purposes and optimize the torque production at the same time. Two-dimensional finite-element analysis has been performed in ANSYS Maxwell 19 to obtain the basic results for the design of the machine. Full article

Osseodensification (OD) compacts trabecular bone during implant site preparation rather than removing it, potentially enhancing primary stability versus conventional drilling. This review critically appraised clinical and preclinical evidence for OD’s biological and biomechanical efficacy in implant dentistry. We conducted electronic searches in seven databases (PubMed, Scopus, Web of Science, ScienceDirect, SciELO, LILACS, DOAJ) for the period January 2014 to March 2024. Studies comparing osseodensification with conventional drilling in clinical and large-animal models were included. Primary outcomes were insertion torque, implant stability quotient (ISQ), bone-to-implant contact (BIC), bone area fraction occupancy (BAFO), and complications. Of 75 retrieved records, 38 studies (27 clinical, 11 preclinical) provided analysable data. Based on descriptive averages from the narrative synthesis, osseodensification increased mean insertion torque by around 45% (range 32–59%) and initial ISQ by 3–10 units compared with conventional drilling. These gains permitted immediate loading in 78% of cases and shortened operating time (mean reduction 15–20 min). Animal studies demonstrated 12–28% higher BIC and increased peri-implant bone density at 4–12 weeks. No serious adverse events were recorded. Postoperative morbidity was similar between techniques. The collated evidence indicates that osseodensification significantly improves primary stability and may accelerate healing protocols, particularly in low-density (Misch D3–D4) bone. However, the predominance of short-term data and heterogeneity in surgical parameters limit definitive conclusions. Long-term randomised controlled trials with standardised protocols are needed before universal clinical recommendations can be established. Full article

As a pivotal component of the single-gear reducer, the casing of the miniature car reducer not only safeguards the internal transmission system but also interfaces seamlessly with the external structure. Currently, the structural design of domestic single-stage reducers primarily leans on experience and standardized specifications. To guarantee the reliable and stable operation of the casing, a high safety factor is often incorporated, which inevitably results in increased weight and necessitates secure bolting connections. This study presents an innovative scheme to design the flange with the box and realize the lightweight nature of the box by finite element analysis to reduce the manufacturing cost. Based on the working state of maximum torque and maximum speed, this study obtains the stress distribution of each bearing seat under different working conditions and carries out static and dynamic analysis combined with other coupling constraints. The analysis results show that the structure has high stiffness and strength, which is suitable for lightweight design, and that the first ten spontaneous vibration frequencies are far away from the excitation frequency of the inner and outer boundary, avoiding the resonance phenomenon. Moreover, this study proposes a new structure design method, which effectively improves the stiffness of the structure. Through the calculation of volume ratio before and after three optimizations, the optimal volume ratio of 30% is selected, unnecessary materials around the bearing seat are removed, and the layout of ribs is determined. After structural optimization, the weight of the shell is reduced by 10.2%, and both the static and dynamic characteristics meet the design requirements. Full article

Background/Objectives: Osseointegration of titanium dental implants is essential for the long-term success of prosthetic treatments. Cold atmospheric pressure plasma (CAP) has recently emerged as a promising surface modification technique aimed at enhancing early osseointegration by improving implant surface properties and exerting antimicrobial effects. This systematic review aims to critically evaluate the in vivo preclinical evidence on the effects of CAP or similar cold plasma treatments on titanium dental implant surfaces with regard to osseointegration outcomes. Methods: A systematic literature search was conducted in PubMed and Scopus databases for preclinical in vivo studies published between 2005 and 2025 investigating the effects of cold plasma on titanium dental implant surfaces. The primary outcome assessed was the bone-to-implant contact (BIC), followed by secondary outcomes including implant stability quotient (ISQ), removal torque, bone area fraction occupancy (BAFO), peri-implant bone density (PIBD), interfacial bone density (IBD), bone-implant direct weight (BDWT) and bone loss measurements via histology and micro-CT. Risk of bias was evaluated using the SYRCLE Risk of Bias tool. Results: Nine eligible studies involving 310 titanium implants in 71 animal models (dogs, pigs and mice) were included. CAP-treated implants consistently demonstrated significant improvements in early osseointegration parameters compared to controls, with statistically significant increases in BIC (up to +20%), BAFO and biomechanical fixation metrics (removal torque and ISQ). Micro-CT analyses revealed enhanced peri-implant bone density and architecture. No adverse biological events or implant failures related to plasma treatment were reported. However, heterogeneity in plasma protocols, animal species and short follow-up durations (2–12 weeks) limited comparability and long-term interpretation. Conclusions: Preclinical evidence seems to support CAP as a safe and potentially effective surface treatment for enhancing early osseointegration of titanium dental implants. Further standardized long-term studies involving functional loading and clinical trials in humans are needed to confirm clinical efficacy and optimize treatment protocols. Full article

In large optical mirror processing (LOMP), the robot is required to carry a computer-controlled optical surfacing (CCOS) polishing tool capable of both fully covering the required material removal profile and maintaining sufficient redundancy for process adaptability. The designed LOMP robot is a five-degree-of-freedom (5-DOF) hybrid robot, where the workspace of its parallel mechanism is constrained by dimensional parameters, including the moving platform radius, the fixed/moving platform radius ratio, and link lengths. This paper presents an optimization study of dimensional parameters for robotic systems, aimed at meeting the workspace requirements of 1250 mm-diameter large optical mirrors. First, analytical models of the robot’s effective workspace and driving torque under different dimensional parameters are derived. Subsequently, workspace requirements and driving torque are established as optimization constraints, and a differential evolution algorithm is implemented to determine the optimal dimensional parameters for the LOMP system. To improve computational efficiency, the conventional differential evolution algorithm is enhanced through the integration of adaptive mutation and crossover operators, resulting in a modified adaptive differential evolution algorithm (ADEA) that demonstrates accelerated convergence characteristics while maintaining solution accuracy. Finally, MATLAB simulations demonstrate that the proposed ADEA successfully obtains optimal dimensional parameter combinations while satisfying all specified constraints. Based on the optimal dimensional parameters, an engineering prototype was manufactured. Experimental results verified the accuracy of the optimized design, providing a valuable reference for optimization of dimensional and structural parameters in similar engineering equipment. Full article

Clear aligners (CAs) have emerged as a widely accepted alternative to conventional fixed orthodontic appliances due to their aesthetic appeal, comfort, and removability. Despite their increasing use, the precise biomechanical behavior of CAs—particularly in relation to maxillary arch expansion and torque control—remains incompletely understood. This scoping review aims to synthesize and critically examine the recent body of evidence derived from finite element analysis (FEA) studies investigating the performance of clear aligners in managing transverse discrepancies and controlling tooth movement. It considered studies published up to April 2025. All included FEA studies assumed dental and bone tissues as linearly elastic, homogeneous, and isotropic, unless otherwise specified. Five in silico studies were included, all employing three-dimensional FEA models to assess the influence of various clinical and design parameters, such as aligner thickness, movement sequence, attachment configuration, and torque compensation. The findings consistently show that movement protocols involving alternating activation patterns and specific attachment designs can significantly improve the efficiency of maxillary expansion, while reducing undesired tipping or anchorage loss. Additionally, greater aligner thicknesses were generally associated with increased force delivery and more pronounced tooth displacement. Although FEA provides a powerful tool for visualizing stress distribution and predicting mechanical responses under controlled conditions, the lack of standardized force application and limited clinical validation remain important limitations. These findings underscore the potential of optimized aligner protocols to enhance treatment outcomes, but they also highlight the need for complementary in vivo studies to confirm their clinical relevance and guide evidence-based practice. Full article