Search Results (12,378)

The high energy consumption of conventional mixers equipped with active mixing elements necessitates the development of more efficient technologies for mixing bulk materials and feed mixtures. This study presents a gravity-driven mixing approach based on the rotation of an inclined cylindrical chamber, eliminating the need for active mixing elements. During chamber rotation, the mixture components move toward both end walls while simultaneously undergoing a circular motion along the inner cylindrical surface. This movement intensifies the mixing process and reduces energy consumption, thereby providing an energy-efficient gravity-based mixing approach that operates without active mixing elements. Laboratory experiments were conducted to determine the key physical and mechanical properties of the sapropel, organic fertilizer, and compound feed (formulation K-60-1). The measured values were as follows: velocity on an inclined steel surface, 0.65–1.21 m/s; coefficient of friction, 0.40–0.91; bulk density, 453–1166 kg/m³; and angle of repose, 36–39°. The experimental results confirmed the validity and adequacy of the developed analytical relationships. A structural and technological design of the gravity mixer was developed, and an experimental prototype was manufactured. Analytical relationships were obtained to determine the critical rotational speed of the chamber, particle movement velocity, and the power required for the mixing process. Under optimal operating conditions, the mixture uniformity reached 95.7% after 4 min of mixing. The mixer productivity was 0.95 t/h, while the specific energy consumption was 0.5 kWh/t, which is 2.5 times lower than that of conventional mixers equipped with active mixing elements. The obtained results confirm the feasibility and effectiveness of the proposed gravity-based mixing method for the preparation of feed and organomineral mixtures under the operating conditions of small-scale farms. Full article

Background: Critically ill patients experience rapid muscle wasting during their ICU stay. Ultrasound (US) and bioelectrical impedance analysis (BIA) are widely used to assess muscle mass; however, their accuracy may be affected by fluid balance alterations. This study aimed to compare the reliability of US and BIA in detecting muscle loss under varying fluid balance conditions in ICU patients. Methods: In this prospective observational study, adult ICU patients with an ICU stay of ≥7 days were evaluated on Days 1, 5, and 7. Muscle thickness was measured using US, and phase angle (PhA) using BIA. Cumulative fluid balance, C-reactive protein (CRP), and lactate levels were recorded. Patients were stratified according to cumulative fluid balance. Results: A total of 143 ICU patients were included in the final analysis. US demonstrated a progressive decrease in muscle thickness (−3.54% ± 10.90% from Day 1 to Day 5 and −7.56% ± 11.82% from Day 1 to Day 7 (both p < 0.0001)), whereas BIA showed no significant change in PhA. Positive fluid balance significantly reduced PhA compared with the negative balance group, p < 0.001, whereas no statistically significant effect on US measurements was detected. CRP > 200 mg/L was associated with greater US-detected muscle loss on Day 5, while lactate > 2.5 mmol/L was associated with lower PhA. Conclusions: Ultrasound reliably identified structural muscle wasting in critically ill patients, with no statistically significant effect of fluid balance detected in this cohort. Furthermore, ultrasound measurements were associated with inflammation-related muscle loss. In contrast, BIA was strongly influenced by hydration and perfusion status, limiting its ability to assess true muscle mass loss in the ICU setting. Full article

Wireless power transfer (WPT) is increasingly used in smart manufacturing, unmanned platforms, and contactless power-supply applications. However, weak coupling, load-dependent impedance drift, and spatial misalignment can shift the resonant condition, leading to unstable output voltage and reduced transfer efficiency. This paper proposes a constant-voltage WPT method that combines a non-uniform winding coupler, parasitic coils, and dynamic capacitor compensation. A composite magnetic coupler with dense outer windings, loose inner windings, and parasitic coils is first developed, and a region-based electromagnetic model is established to characterise self-inductance, mutual inductance, and coupling coefficients. An improved LCC-S compensation network with a dynamic capacitor compensation matrix is then derived to keep the system close to resonant operation at the nominal 85 kHz operating point under load variation and coil-displacement-induced coupling changes. A zero-voltage-switching-angle tracking method with mutual-inductance correction is further introduced to compensate for phase deviation and maintain soft-switching operation through limited switching-frequency adjustment. Experimental validation demonstrates that the system maintains a stable constant-voltage output across a load range of 20–50 Ω and under 5 cm lateral and longitudinal offsets. The measured efficiency remains above 89% and reaches 93.7% under the optimal coupling and load-matching condition. Full article

Objectives: This study aimed to evaluate the utility of MRI-based morphometric and qualitative parameters in identifying patients with suspected normal pressure hydrocephalus (NPH) associated with shunt surgery selection following clinical and lumbar puncture evaluation. Methods: We retrospectively analyzed 134 participants: 84 symptomatic patients evaluated for suspected NPH and 50 age-matched controls with normal brain MRI findings. Symptomatic patients were categorized according to subsequent clinical management following lumbar puncture evaluation into those who underwent shunt surgery (Shunt group) and those who received conservative management (Conservative group). The Evans index, fronto-occipital horn ratio (FOHR), bicaudate index, callosal angle, ventricular measurements, and disproportionately enlarged subarachnoid space hydrocephalus (DESH) components were analyzed. The discriminatory performance of MRI parameters for shunt surgery selection was assessed using ROC analysis; independent predictors of shunt surgery selection were determined using logistic regression. Results: Although conventional ventricular indices and ventricular dimensions were significantly greater in symptomatic patients than in the control group (p < 0.001), baseline continuous MRI measurements did not significantly differ between the Shunt and Conservative groups (p > 0.05). Callosal angle demonstrated no discriminatory value for shunt surgery selection. In univariate analyses, an Evans Index > 0.36, a bicaudate index > 0.23, and a DESH score > 2 were associated with shunt surgery selection. High-convexity tightness and an Evans Index > 0.36 differed significantly between groups and remained independently associated with shunt surgery selection in multivariable analysis. Conclusions: Ventricular width-based indices alone appear insufficient for identifying patients selected for shunt surgery among individuals evaluated for suspected NPH. Both qualitative and quantitative MRI features, particularly high-convexity tightness and an Evans Index > 0.36, were independently associated with shunt surgery selection following routine clinical assessment. Integrating multimodal imaging parameters with clinical evaluation may provide a more reliable approach for identifying patients who are ultimately selected for shunt surgery following lumbar puncture assessment. Full article

This paper investigates the feasibility of 3D self-localization and tracking using chipless radio frequency identification (RFID) tags operating in the terahertz (THz) frequency band. The primary objective is to achieve sub-millimeter (sub-mm) localization and tracking accuracy while minimizing reliance on external infrastructure. To this end, a hybrid localization framework is proposed that jointly exploits round-trip time-of-flight (RToF) and angle-of-arrival (AoA) measurements to enhance localization performance. Although near-field propagation effects are inherently significant in the considered THz operating regime, a simplified far-field approximation is adopted to facilitate tractable system modeling and analytical development. The proposed framework is further extended to dynamic scenarios through an extended Kalman filter (EKF)-based tracking algorithm, which incorporates temporal state evolution to improve estimation robustness under noisy measurements. Furthermore, the Cramér–Rao lower bound (CRLB) for the hybrid RToF-AoA system is derived to establish the fundamental limits of localization accuracy under varying system configurations and measurement conditions. Simulation results demonstrate that the proposed approach is capable of achieving sub-mm localization and tracking accuracy with a highly constrained anchor infrastructure, including operation with a single anchor in the considered scenario. These findings highlight the potential of THz chipless RFID technology as a promising enabling solution for next-generation high-accuracy localization and tracking applications. Full article

The absence of discrete element contact parameters for suitable harvest rapeseed pods hinders accurate DEM simulations. This study presents the first systematic calibration of discrete element contact parameters for “Ningza 158” rapeseed pods using physical and simulation experiments. Experimentally determined properties included external dimensions, density, pod–steel coefficients (restitution, static friction, rolling friction), and pod–pod restitution. Using the measured angle of repose as the objective, significant parameters were screened, optimized, and modeled via Plackett–Burman, steepest climbing, and central composite response surface tests. The optimal parameter combination was then validated against the angle of repose, completing the calibration. The results showed that the density, Poisson’s ratio, and shear modulus of rapeseed pods at the suitable harvest period were 346.63 kg·m⁻³, 0.35, and 10.5 MPa, respectively. The coefficients of restitution, static friction, and rolling friction for pod–steel and pod–pod were 0.2994, 0.4206, 0.0435, 0.1024, 0.3110, and 0.0380, respectively. Under this simulation parameter combination, the angle of repose obtained from the simulation was 71.23°, yielding a relative error of 2.12% compared with the actual value of 69.75°. Note that this validation is limited to static accumulation behavior. The calibrated parameters can be a basis for future dynamic validation studies on harvest loss mechanisms, provided additional dynamic validation is performed. Full article

Accurate solar irradiance forecasting is important for efficient planning of solar energy systems, renewable energy integration, and data-driven energy management in smart cities. This becomes more essential in regions with limited measured data availability and varying climatic conditions, where reliable forecasting can support urban energy planning and smart grid operation. Pakistan faces a scarcity of available solar data and has varying climatic conditions, which makes it ideal for such a study. This study utilizes nine geographically diverse stations to develop a benchmark framework for direct one-step-ahead hourly solar irradiance forecasting. The dataset was subjected to data preprocessing, feature engineering, and multi-model evaluation. A staged approach was adopted for feature selection, starting from a base model comprising three input variables: extraterrestrial radiation, solar zenith angle, and relative humidity. Features were added in an incremental order, which resulted in an optimized four-variable input set through the addition of a lagged clearness index to the base model. The forecasting models evaluated in this study, using these input variables, were ANN, NAR, NARX, LSTM, GRU, SARIMA, and Prophet. Deep learning models outperformed the other considered approaches, with LSTM showing the best overall benchmark performance with an average RMSE of 92.93 W/m², MAE of 66.56 W/m², and R-Squared of 0.872. The performance trends were broadly consistent across the evaluated stations, indicating stable behaviour within the adopted dataset and experimental setup. The study shows that a compact and physically interpretable input feature set, used with recurrent deep learning models, provides an effective solution for hourly solar irradiance forecasting, especially in locations with varying climatic conditions. The proposed benchmark can support smart city applications related to distributed solar generation, energy-aware urban planning, and intelligent operation of renewable-rich power systems. Full article

To enhance the fidelity of the DEM representation of sugar beet roots, the root geometry was reconstructed from three-dimensional scanning data and represented in EDEM2024 as a multi-sphere clump. The Hertz–Mindlin (no slip) model was used to describe particle contact behavior. The root–Q235 steel contact parameters were determined by drop-rebound, inclined-plane sliding, and inclined-plane rolling experiments. For root–root interactions, the parameters were further refined through cylinder-lifting repose-angle simulations combined with the steepest-ascent method and a three-factor quadratic orthogonal rotatable regression scheme. The optimized inter-root restitution coefficient, static friction coefficient, and rolling friction coefficient were 0.534, 0.728, and 0.080, respectively. With this parameter set, the deviation between the simulated and measured angles of repose was 0.86%, and the error obtained in the independent validation test was 1.5%. These results demonstrate that the proposed DEM model and calibrated parameter set can accurately represent the motion and contact behavior of sugar beet roots. Full article

Determining the 3D position of a vehicle from a 2D image plays a key role in video surveillance, autonomous driving, and spatial localization. However, localization accuracy can significantly degrade in conditions of incomplete or synthetic measurement noise and keypoint jitter. In this paper, we propose a new iterative 3D position estimation algorithm (KGA). This algorithm includes geometric correction and calibration steps for converting from 2D to 3D coordinates; trajectory prediction and correction using a Kalman filter; and adaptive tuning of the filter parameters using the Goldschmidt algorithm. Experiments confirm that KGA outperforms the standard (FK) and modified (MFK) Kalman filters in accuracy and convergence speed, demonstrating robustness to various camera angles and noise levels. The novelty of this approach lies in the integration of the Goldschmidt algorithm into the Kalman filter to create an adaptation mechanism that dynamically adjusts the measurement noise covariance based on instantaneous innovation magnitude. Unlike end-to-end deep learning trackers or nonlinear filters (EKF/UKF), KGA is designed as a lightweight post-processing stage that can be seamlessly integrated into existing detection pipelines while maintaining the low computational footprint required for UAV-based edge deployment. The algorithm is of practical value for computer vision systems requiring accurate and robust tracking under varying observational conditions, with current implementation suitable for offline or buffered processing, and clear pathways to real-time deployment through code optimization. The algorithm is of practical value for computer vision systems requiring accurate and robust tracking under varying observational conditions. Full article

Background/Objectives: To determine whether ESS provides superior clinical, radiologic, or perioperative outcomes compared with non-ESS surgical strategies in lumbar spondylolisthesis. Methods: We conducted a PRISMA-guided systematic review and meta-analysis comparing ESS with non-ESS strategies specifically for lumbar spondylolisthesis. PubMed, Web of Science, Scopus, and CENTRAL were searched from inception to December 2025, plus reference-list screening. Primary outcomes were mean change in VAS back pain, VAS leg pain, and Oswestry Disability Index (ODI); secondary outcomes included radiologic measures (disc height, lumbar lordosis angle, fusion rate) and perioperative outcomes (blood loss, operative time, length of stay, complications). Results: Eighteen studies (16 retrospective cohorts, 1 RCT, 1 case–control) involving 1200 patients with lumbar spondylolisthesis (2019–2025) were included. ESS showed no significant differences versus non-ESS in mean change in VAS back pain (13 studies; MD −0.07), VAS leg pain (14 studies; MD 0.08), or ODI (12 studies; MD 0.51). No statistically significant differences were detected in radiological outcomes (disc height, lumbar lordosis angle, and fusion rate). ESS was associated with reduced blood loss (MD −132.98) and shorter hospital stay (MD −2.86 days), with no difference in operative time (MD 3.96) or postoperative complications (RR 0.86). Subgroup analyses compared endoscopic fusion with MIS fusion, open fusion, and non-endoscopic decompression. Endoscopic versus MIS fusion showed lower blood loss (MD: −50.9 mL) and shorter hospital stay (MD: −1.4 days) but longer operative time (MD: +17.2 min), with no differences in clinical outcomes. Comparisons involving decompression and open fusion were limited by the small number of studies and should be considered exploratory. Conclusions: For lumbar spondylolisthesis, no statistically significant differences were detected between ESS and non-endoscopic approaches in pain, disability, radiologic outcomes, or complication rates, with potential perioperative advantages in blood loss and length of stay. However, these findings should be interpreted cautiously because the available evidence is predominantly retrospective, procedurally heterogeneous, and affected by substantial variation in follow-up duration. Full article

In underground engineering, the dynamic failure mechanisms of rock masses containing openings under impact loading are of vital importance. This study systematically investigates the effects of opening shape, size, and orientation on the dynamic behavior of red sandstone. Dynamic impact tests are first performed using a split Hopkinson pressure bar together with high-speed photography and digital image correlation for full-field strain and crack monitoring. A two-dimensional combined finite–discrete element (FDEM) model is then developed to reproduce the dynamic failure process. It is found that the opening size significantly affects the dynamic compressive strength, while the opening shape dictates crack initiation and propagation. Circular openings induce symmetric cracking, square openings cause corner-dominated cracks, and horseshoe-shaped openings produce asymmetric failure whose dominant side depends on the rotation angle. The FDEM model established in this study successfully reproduces the main crack paths and failure modes observed in experiments, which provides a powerful tool for the analysis of rock dynamic failure. Moreover, the results in this study also provide practical engineering guidance for the reinforcement and support measures for different opening shapes. Full article

To investigate the non-uniform gas–solid flow and insufficient particle residence time in an Ende pressurized pulverized-coal gasifier (EPCG), a three-dimensional cold-state numerical model of a 45,000 Nm³/h industrial-scale gasifier was established to study the effects of nozzle deflection angles (30–50°) and nozzle inclination angles (15–23°) on gas–solid flow characteristics. (1) Considering the difficulty of directly measuring particle flow behavior inside a pressurized gasifier, industrial-scale cold-state simulations were conducted to analyze particle transport and flow evolution under different nozzle structures; (2) flow uniformity and stability were comprehensively evaluated using axial velocity, particle volume fraction, residence time, and radial symmetry, and the different effects of nozzle deflection angle and nozzle inclination angle were comparatively analyzed. The results show that a typical wall-attached upward flow and central recirculation structure is formed in the bed, with particles exhibiting spiral upward transport. Flow uniformity gradually improves with increasing bed height. Increasing the nozzle deflection angle mainly enhances particle transport, whereas the nozzle inclination angle has a more significant effect on flow symmetry and stability. Nozzle inclination angles of 19–21° and nozzle deflection angles of 40–45° are more favorable for stable flow formation, while the 40°/19° configuration gives the best flow uniformity and stability. Full article

The motion of AC electromagnetic actuators exhibits complex electrical–magneto–mechanical coupling characteristics. A three-phase AC contactor is taken as the typical research object in this paper. Using the finite-element method (FEM) and mesh deformation technique, the commercial software COMSOL Multiphysics is adopted to analyze its static electromagnetic characteristics, together with the operational coil current response and movable core displacement. In addition, the static correlation between the magnetic force, air gap, and time-varying magnetic force curves in the movement process are obtained. An experimental platform is established to measure the magnetic force of electromagnetic actuators. The experiment results demonstrate the feasibility of the proposed simulation method. The normalized root mean square errors between simulated and measured static magnetic forces are below 8% under all tested coil voltages. Furthermore, the effect of coil voltage phase angle on dynamic operational characteristics is thoroughly investigated. Combined with the closing time and final velocity of the movable core, the recommended operating window and its corresponding phase angle are determined. Full article

European catfish, an invasive alien species (IAS) that inhabits the Tagus River in Extremadura, is a threat to freshwater biodiversity and the local economy. As a freshwater mega-predator, it eats all kinds of fish, impacting local ichthyofauna as well as sport-recreational angling, a major economic driver in Extremadura, with 100,000 angling licenses issued by the Extremadura local government and more than 1000 annual bank fishing competitions. The introduction of Silurus glanis into Tagus basin is recent, dating to the 20th century, but it has rapidly spread. Although this expansion is driven by anglers, boat anglers account for only two per thousand anglers in the region, and even among them European catfish anglers are scarce, as fishing for this species is prohibited in the region and local anglers and anglers associations are against European catfish expansion. Efforts to control catfish in Extremadura have been based on studies of selective capture methods, such as trammel nets, gill nets, long lines, fish traps, and electrofishing combined with nets in areas where barbel congregate during their spawning migration. The most effective and selective methods for European catfish, avoiding bycatch, are trammel nets and electrofishing. Therefore, a combination of these methods and collaboration between local government and anglers are proposed for its control in reservoirs. In cases of recent introductions into standing water, rapid actions have been taken, involving complete drainage of the water body, rescue of native fish and removal of European catfish. These measures are feasible in reservoirs up to 10 hectares and can be combined with sediment management to improve water quality. Deterrence and control measures have been implemented in response to the promotion of catfish angling in regional media and on social media. To control European catfish expansion, collaborative actions involving public agencies, local government, angler associations and public awareness are essential. Full article

Background: Cervical extension type is commonly associated with forward head posture and altered cervical and scapular muscle activity. However, the comparative effects of cervical stabilization exercises combined with scapular stabilization exercises or thoracic exercises remain unclear. Objective: In this study, we aimed to compare the effects of cervical stabilization exercises combined with scapular stabilization exercises and cervical stabilization exercises combined with thoracic exercises on head posture and muscle activity in individuals with cervical extension type. Methods: Thirty-two university students with cervical extension deformity were randomly assigned to either a cervical spine stabilization combined with scapular stabilization training group or a cervical spine stabilization combined with thoracic spine training group. Baseline demographic and anthropometric characteristics, including sex, age, height, weight, and body mass index, were comparable between the groups. Both groups received a 4-week intervention consisting of stretching, strengthening, and postural correction exercises, performed three times per week. Head posture was assessed using the craniovertebral angle (CVA) and cranial rotation angle (CRA), and the muscle activity of the sternocleidomastoid (SCM), upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) was measured using surface electromyography. Paired t-tests and two-way repeated measures ANOVA were used for statistical analysis. Results: No significant differences were observed in the general characteristics between the two groups at baseline. After the intervention, both groups showed significant improvements in CVA and CRA compared with baseline. Compared with the CTG, the CSG showed significantly greater reductions in SCM and UT activity and significantly greater increases in LT and SA activity. Significant time effects and group-by-time interaction effects were identified for selected head posture and muscle activity variables. Conclusion: Cervical stabilization exercises combined with scapular stabilization exercises may be more effective than cervical stabilization exercises combined with thoracic exercises in improving head posture and optimizing neck and scapular muscle activity in individuals with cervical extension type. Full article