Search Results (1,736)

Heated tobacco products (HTPs) frequently induce user discomfort due to high mainstream smoke temperatures. To address this challenge and improve the inhalation experience, this experiment designed and prepared a cage-shaped braided tube as the cooling section of the filter for HTPs. The thermal, cooling, suction resistance, and smoke composition properties of the filter were tested and analyzed. Thermal analysis (DSC/TG) revealed a 116.53 J/g increase in endothermic enthalpy for PEG-impregnated samples, accompanied by maintained thermal stability (decomposition temperature ≈ approximately 350 °C). The 0.8 wt% Carbon Nanotube (CNT) composite achieved exceptional thermal conductivity (0.597 W/m·K), representing a 521% improvement over untreated controls. The braided tube optimal performance (3 mm inner diameter, 30% PEG/0.8% CNT) reduced the highest smoke temperature to 47.8 °C while maintaining acceptable suction resistance (68.5 Pa, 56.4% reduction vs. commercial IQOS filters). GC-MS analysis confirmed negligible alterations in smoke composition (p > 0.05). This innovation offers an effective thermal management solution that does not compromise sensory experiences. Full article

In the light of increasing research into amorphous composites and their applications, as-cast specimens of multicomponent Ti₄₈Zr₁₈V₁₂Cu₅Be₁₇ amorphous composites were prepared via water-cooled copper mold suction casting. Subsequently, the as-cast specimens were subjected to semi-solid isothermal treatment to obtain semi-solid specimens. Taking the semi-solid specimens as the research object, room temperature compressive deformation behavior was investigated by analyzing the shear band characteristics on the side surfaces of the compressed specimens. The evolution of shear bands at various stages of plastic deformation was investigated via scanning electron microscopy (SEM). Additionally, significant work hardening was observed after yielding. Surface deformation morphologies indicate that the work-hardening behavior is associated with plastic deformation, interactions between shear bands, and interactions between shear bands and β-Ti crystals. Experiments have demonstrated that at a specific deformation extent, shear bands preferentially initiate at the crystal–amorphous matrix interface. In the final stage of plastic deformation, shear bands propagate through work-hardened β-Ti crystals into the amorphous matrix, with their propagation retarded by the β-Ti crystals. When shear bands in the amorphous matrix are obstructed by β-Ti crystals and can no longer propagate, some evolve into cracks. These cracks then propagate exponentially, leading to eventual fracturing of the specimens and termination of plastic deformation. The research findings provide a theoretical basis for analyzing the deformation capacities of various amorphous composites. Full article

To investigate the effects of clearance variations induced by back wear ring wear on internal flow and noise within centrifugal pumps at the design flow rate (Q_o = 25 m³/h), a combined Computational Fluid Dynamics (CFD) and Acoustic Finite Element Method (FEM) approach was employed. The SST-SAS turbulence model and Lighthill’s acoustic analogy, were applied to simulate the internal flow and acoustic fields, respectively, across four different clearance values. The impact laws of various back wear-ring clearances on flow-induced noise were analyzed. The results indicate that the head and efficiency of the centrifugal pump gradually decrease with the increase in the back wear-ring clearance. When the clearance reaches 1.05 mm, the head drops by 4.35% and the efficiency decreases by 14.86%. The radial force on the impeller decreases, while the axial force increases and its direction reverses by 180 degrees. The acoustic source strength at the rotor–stator interface, near the volute tongue, and at the outlet of the back wear ring increases with larger clearance; furthermore, high-sound-source regions expand around the balance holes and near the impeller suction side. The dominant SPL frequency for all clearance cases was the blade passing frequency (BPF). As clearance increases, the overall SPL curve shifts upwards; however, the variation gradient decreases noticeably when the clearance exceeds 0.75 mm. The overall internal SPL increases, with the total SPL under 1.05 mm being 1.8% higher than that under 0.15 mm. In total, the optimal back ring clearance is 0.45 mm, which achieves a 38% noise reduction while maintaining a 97.9% head capacity. Full article

This paper addresses the critical challenge of insufficient solid-phase suction capacity in jet pumps during vacuum sand cleanout operations for low-pressure oil and gas wells. Through integrated numerical simulations validated by experimental measurements with under 15% error, a kind of nonlinear interaction mechanism among key operational and solid-phase parameters is revealed in this paper. The results demonstrate that due to intensified turbulent dissipation, particle diameters exceeding 0.5 mm will lead to a significant decrease in pump efficiency, while an increase in solid volume fraction can improve the solid transport rate but will reduce the energy conversion efficiency. Working pressure optimization shows that the pump efficiency will reach its maximum when the work pressure is 5 MPa, while if it is 8 MPa, the solid transport capacity will be increased by 116%. A discharge pressure exceeding 2.5 MPa will reduce the suction pressure difference and disrupt solid phase transport. A novel dual-metric framework considering the solid transport rate and pump efficiency is put forward in this paper, which includes limiting the particle diameter to 0.5 mm or less, maintaining a solid volume fraction below 30%, and keeping the working pressure between 5 and 8 MPa and the discharge pressure at 2.5 MPa or lower. This method can increase the sand removal efficiency to over 30% while minimizing energy loss, providing a validated theoretical basis for sustainable wellbore repair in depleted oil reservoirs. Full article

The inclusion of an inducer is an effective approach to improve the cavitation performance of centrifugal pumps, significantly influencing both the internal flow characteristics and the external performance of the pumps. This study examines a miniature high-speed centrifugal pump (MHCP) using numerical simulations based on the k-ε turbulence model, comparing the cases with an inducer and without one. Experimental tests on the pump’s external performance are conducted and flow visualization images are presented to validate the findings. The effects of the inducer on the tip leakage backflow, cavitation performance, and external pump performance are analyzed. The results show that the inducer provides pre-pressurization of the fluid, leading to a higher circumferential velocity at the impeller inlet and a reduced inlet flow angle. This allows for a reduction in the impeller blade inlet angle, resulting in smoother flow streamlines inside the impeller. Moreover, the inducer helps to suppress local low-pressure regions caused by the vortex and cavities generated by the interaction between the tip clearance backflow and the main flow, thereby mitigating cavitation in the non-blade zone. Within the investigated operating range, the pump with an inducer exhibits a significantly improved external hydraulic performance, including an increased head and efficiency, a reduced required net positive suction head (NPSHr), and a broader stable operating range. Full article

Polyp retrieval following colorectal polypectomy remains a critical step for histopathological analysis and determining appropriate surveillance intervals. Despite reported retrieval rates exceeding 90% in the literature, significant heterogeneity persists in clinical practice, particularly for polyps < 10 mm, due to the lack of standardized retrieval methods. This review synthesizes current evidence on polyp retrieval techniques, the impact of lesion size, and device-specific considerations, including suction-based methods, retrieval nets, and other approaches such as the water-bolus and water-slider techniques. We also examine the clinical utility and limitations of the “resect and discard” and “diagnose and leave in situ” strategies, highlighting barriers to widespread implementation such as medico-legal risks, variability in optical diagnosis, and discrepancies across international guidelines. The integration of advanced imaging technologies, including high-definition endoscopy, virtual chromoendoscopy, and artificial intelligence-driven computer-aided diagnosis (CADx), represent promising tools to help in increasing the diagnostic accuracy of diminutive polyps. As post-polypectomy surveillance recommendations remain tethered to histological findings, this review underlines the need for updated, evidence-based frameworks that take into account technological advancements while ensuring diagnostic precision, cost-effectiveness, and patient safety in colorectal cancer prevention. Full article

Loess, a typical unsaturated soil, is a Quaternary sedimentary deposit widely distributed across arid and semi-arid regions worldwide. In recent years, global climate change has led to significant temperature fluctuations in Northwest China, impacting loess properties and soil–water characteristic curves (SWCCs). This study investigated typical loess deposits in Mizhi County, Shaanxi Province, systematically analyzing their basic physical properties and microstructure. The SWCCs of the loess were measured at three temperature gradients (15 °C, 20 °C, and 25 °C) using the dynamic dew-point isotherm method to investigate the impact of temperature on SWCC hysteresis. The results showed that with increasing temperature, the SWCC exhibited increasing divergence. The magnitude of the water content change and the corresponding suction forces along the wetting and drying paths increased, leading to an enlargement of the hysteresis loop area. These findings indicate that temperature significantly affects the hysteresis behavior of loess, providing a certain basis and ideas for the study of the soil–water characteristic curves of unsaturated soils such as loess under the influence of temperature. Full article

Sludge dewatering is a key step in the overall process of sludge treatment and disposal. In this study, ferric tannate was synthesized by chemically complexing tannic acid with Fe₂(SO₄)₃ under various conditions and then was innovatively employed to enhance electrochemical conditioning (ECC) for municipal sludge dewatering. The optimal preparation conditions of ferric tannate were determined as a tannic acid to iron ion molar ratio of 0.8:10, pH of 10, and reaction time of 2 h. Subsequently, ferric tannate-enhanced ECC was investigated under different dosages and operating parameters. The optimal conditions were identified as ferric tannate dosage of 20% total solid, voltage of 50 V, and reaction time of 30 min, under which capillary suction time, specific resistance to filtration, and water content of dewatered sludge cake decreased by 84.3%, 84.2%, and 17.6%, respectively. Results of the mechanism analysis indicated that ferric tannate effectively reduced sludge viscosity, increased zeta potential, and neutralized the negative surface charges via charge neutralization, hydrophobic interactions, and hydrogen bonding. Meanwhile, adsorption bridging promoted floc aggregation and particle growth. Compared with the ECC process alone, the addition of ferric tannate in the ferric tannate-enhanced ECC process generated more ^•OH, promoting the extracellular polymeric substance degradation and protein removal, thereby improving sludge hydrophobicity. Furthermore, the floc structure was reconstructed into a more compact and smooth morphology, facilitating the release of bound water during filtration. These findings provide new technical and theoretical support for the development of eco-friendly and efficient sludge conditioning and dewatering processes. Full article

Although cyclic adenosine monophosphate (cAMP) is not a major secondary messenger in the visual transduction cascade in vertebrates, it may modulate photoreceptor functions. The effects of cAMP have been extensively studied in rods; however, its role in cones remains less understood. The aim of this study was to investigate the effects of increased levels of cAMP on the photoresponses of isolated blue- and green-sensitive cones in adult zebrafish (Danio rerio). To examine the effects of elevated cAMP on individual cone spectral types, photoreceptor currents were recorded using a suction pipette method. The adenylate cyclase activator forskolin was used to increase intracellular cAMP levels. Sensitivity and photoresponse parameters were compared before and after forskolin application. An increase in cAMP levels has similar effects on photoresponses of blue- and green-sensitive cones. Forskolin application to both types of cones resulted in a slight increase in sensitivity, with significant slowing of the phototransduction cascade shutdown processes and a marked increase in the integration time of photoresponses. These findings suggest that intracellular cAMP levels, which fluctuate in the retina during the diurnal cycle, can modulate cone function. The observed effects of cAMP are consistent with its action on one of its main putative targets, opsin kinases. Full article

Background: In 2016, the neonatal resuscitation program (NRP) changed its recommendation to perform endotracheal suctioning in non-vigorous neonates born through meconium-stained amniotic fluid (MSAF). The objective of this study is to compare outcomes in non-vigorous neonates born through MSAF before and after the change in the NRP’s recommendations. Methods: This is a retrospective cohort study in a single center assessing all neonates ≥34 weeks of gestation with MSAF in 2010–2015 (pre-implementation of new guidelines) and 2017–2022 (post-implementation of new guidelines). Results: Neonates receiving tracheal suctioning were more likely to be diagnosed with MAS (29.3% vs. 19.7%; p = 0.03) and PPHN (8.9% vs. 2.5%; p = 0.003) and more likely to receive surfactant (7.6% vs. 3.2%; p = 0.03). Conclusions: In our institution, non-vigorous neonates born via MSAF after the change in NRP guidelines were less likely to be diagnosed with MAS and PPHN and were less likely to receive surfactant. Our study supports current NRP guidelines. Full article

Background: Eximia is a non-invasive body-contouring technology combining ultrasound cavitation, radiofrequency, and vacuum suction to reduce adiposity. EMS Pro Bodytech delivers biphasic electrical impulses to stimulate muscular contractions and improve muscle performance. Methods: A 6-week observational study included 77 participants (58 women aged 28–55 and 19 men aged 20–49), who received twice-weekly sessions combining Eximia and EMS training. Anthropometric and body composition measurements were recorded before and after the intervention. Results: Participants showed reductions in fat mass (mean from 19.21 kg to 18.19 kg; SD from 8.23 to 8.42), BMI (mean from 26.03 to 25.68; SD from 4.26 to 4.16), and visceral fat index (mean from 4.97 to 4.74; SD from 2.88 to 2.99), alongside an increase in skeletal muscle percentage (mean from 37.34% to 38.3%, SD from 5.09 to 5.94). Statistical analysis revealed no significant differences in treatment response between genders (e.g., BMI: p = 0.080; fat-free mass: p = 0.089) or age groups (all p > 0.6), suggesting that the intervention was effective across demographics. Conclusions: The combined approach of Eximia body remodeling and EMS muscle stimulation led to measurable improvements in body composition, independent of age or gender. These findings support its potential as a non-invasive, inclusive strategy for body reshaping alongside peri-procedural dietary standardization. Full article

Intubated critically ill patients are susceptible to secretion accumulation because of compromised airway clearance. Various airway clearance interventions are employed to prevent complications arising from mucus retention. This Delphi study aims to collect global opinions in an international expert panel of ICU professionals on the usefulness of these various airway clearance interventions. A steering committee performed a literature search informing the formulation of statements. Statements are grouped into two distinct parts: (1) Humidification and Nebulization, and (2) Suctioning and Mucus mobilization techniques. For each part, a diverse panel of 30–40 experts will be selected, with concerted effort to involve experts from various medical specialties involved in airway clearance methods. Multiple choice questions (MCQs) or 7-point Likert-scale statements will be used in the iterative Delphi rounds to reach consensus on various airway clearance interventions. Rounds will continue until stability is achieved for all statements. Consensus will be deemed achieved when a choice in MCQs or a Likert-scale statement achieves ≥75% agreement or disagreement. Starting from the second round of the Delphi process, stability will be assessed using non-parametric χ² tests or Kruskal–Wallis tests. Stability will be defined by a p-value of ≥0.05. Full article

The supercritical carbon dioxide (S-CO₂) Brayton cycle has become one of the most promising power generation systems in recent years. Owing to the high density of S-CO₂, the turbine operates with a lower flow coefficient and a reduced blade height compared to conventional gas turbines, leading to relatively higher tip leakage and secondary flow losses. A properly designed partial admission scheme can increase blade height and improve turbine efficiency. In this study, the effects of partial admission ratio on the performance and flow characteristics of a partial admission S-CO₂ turbine were investigated using numerical methods. The results indicate that the decline in turbine efficiency accelerates when the partial admission rate falls below 0.3. Furthermore, the maximum blade torque begins to decrease once the partial admission ratio drops below 0.1. Stronger tip passage vortices and a large-scale leakage vortex were identified in the passage located at the sector interface. Blade loading analysis revealed a reduction in pressure on the pressure surface of blades just entering the active sector, and a significant increase in suction surface pressure for blades about to exit the active sector. These pressure variations result in reduced blade torque near the boundaries of the active sector. Full article

Microneedle (MN)–tissue interactions play a critical role in the efficiency and reliability of transdermal drug delivery and biosensing, yet their mechanistic understanding remains limited. This study systematically investigates the effects of biological (tissue type and temperature) and mechanical (needle design, material, and insertion velocity) parameters on the performance of microneedle insertion and extraction. Experiments were performed on porcine skin, chicken breast, and agarose gel to represent varying tissue properties. Additionally, the effect of tissue temperature on replicating physiological conditions, such as hypo- and hyperthermia, was evaluated using porcine skin as the sample. A novel conical MN design integrated with surface suction-cup structures was developed to improve tissue adhesion. Mechanical responses were analyzed through force–displacement measurements, evaluating insertion force, extraction force, and relaxation time. Results show that elevated tissue temperature reduces insertion and extraction forces while shortening relaxation times, indicating increased tissue compliance. The suction-cup MNs significantly enhanced needle–tissue adhesion, with the most pronounced effect observed in chicken breast tissue, achieving more than a four-fold increase in extraction force compared to conventional conical needles. These findings provide valuable insights into optimizing the design of MNs for advanced biomedical applications. Full article

To address the issue in high-throughput longitudinal axial-flow grain combine harvester cleaning systems, in which the extended length of the cleaning chamber results in airflow velocity attenuation and makes it difficult to efficiently and rapidly remove light impurities, a front-blowing and rear-suction enhanced cleaning technology and device was developed. Based on the investigation of the movement characteristics of the cleaning airflow within the cleaning chamber, a theoretical model was established to describe the velocity variation of the front-blowing and rear-suction enhanced cleaning airflow. CFD simulation software was employed to conduct a comparative analysis of the airflow field structure before and after improvement, aiming to identify the influence patterns of key structural parameters on the airflow field distribution. An orthogonal experiment with three factors and three levels was conducted on the improved cleaning system, focusing on the suction fan speed, vertical installation height of the suction fan, and horizontal distance between the suction fan and the sieve surface. The influence of each factor on the airflow field was analyzed, and the optimal parameter combination was obtained. When the suction fan speed was 2275 r/min, the vertical installation height was 72.5 mm, the horizontal distance to the sieve surface was 385 mm, and the airflow non-uniformity coefficient at the rear part of the screen surface was 11.17%, with a relative error of 4.39% compared to the optimization result. Finally, bench tests were conducted to verify the accuracy of the simulation results. Compared to that before improvement, the airflow non-uniformity coefficient at the rear part of the screen surface in the cleaning chamber was reduced by 59.43%, significantly improving the uniformity of airflow distribution. These findings provide both theoretical and technical support for improving the cleaning efficiency and operational performance of high-throughput grain combine harvesters. Full article