Search Results (367)

Based on experimental data regarding the local distribution of metallic impurities in raw selenium and the composition of its vapor phase, the potential composition of the vapor–droplet suspension that leads to reduced condensate quality due to impurities with low partial vapor pressures relative to selenium, as well as metals with vapor pressures comparable to selenium, has been hypothesized. Due to selenium’s high aggressiveness towards structural materials and based on economic feasibility, the use of low-alloy steel of ordinary quality for the technical design of the distillation process, instead of alloyed steel, has been thermodynamically justified. A method has been developed, and a device to refine selenium has been manufactured, which differs from existing ones by the inertial purification of the vapor phase from droplet suspension. The development is protected by a security document (patent KZ No. 37275). Based on the completed developments, an industrial prototype of such equipment has been designed and implemented in production. Full article

Thermal sensors are widely used in medical, industrial and other fields, where the requirements for high sensitivity and portability continues to increase. Here we propose a suspended bridge structure fabricated using MEMS, which effectively shrinks the size and reduces heat loss. This study reviews current sensor-related theories of heat conduction, convective heat transfer and thermal radiation. Heat loss models for suspended and non-suspended bridge structures are established, and finite element analysis is conducted to evaluate their thermal performance. The thermal performance of the suspended bridge structure is further validated through infrared temperature measurements on the manufactured sensor device. Theoretical calculations demonstrate that the proposed suspension bridge structure reduces heat loss by 88.64% compared with traditional designs. Benefiting from this improved heat retention, which was also confirmed by infrared thermography, the thermal sensor fabricated based on the suspension bridge structure achieves an ultra-high sensitivity of 0.38 V/W and a fast response time of less than 200 ms, indicating a high accuracy in thermal characterization. The correlation coefficient obtained for the sensor output voltage and input power of the sensor is approximately 1.0. Based on this design, multiple microfluidic channels with suspended bridge structures can be integrated to realize multi-component detection, which is important for the development of multifunctional biomedical detection. Full article

The study of the effects of 2.45 GHz electromagnetic fields on the health and safety of people and organisms as a whole is essential due to their widespread use in everyday life. It is known that they can cause thermal and non-thermal effects—at the molecular, cellular and organismal level. Yeast suspensions were treated with 2.45 GHz microwave radiation in the near-field of antenna at two distances (2 and 4 cm) and two time periods (20 and 60 min)—setups resembling the use of mobile devices. The release of UV-absorbing substances from the cells was studied as an indicator of membrane permeabilization, total intracellular antioxidant activity and reduced glutathione were determined, and a comet assay for damage to the DNA was performed. A correlation between reduced antioxidants and increased membrane permeability during EMF treatment was observed at a distance of 2 cm for 20 min, suggesting the presence of oxidative stress, while a similar effect was not observed with conventional heating. Slightly increased membrane permeability was observed after irradiation for 60 min at a distance of 4 cm, but this was not related to the antioxidant status of the cells. A trend towards increased DNA damage was observed under both conditions. Full article

Transparent conductive electrodes (TCEs) are essential components in modern optoelectronic devices, including organic light-emitting diodes and solar cells, sensors, and flexible displays. Indium tin oxide has been the dominant material for TCEs due to its high transparency and conductivity. However, its brittleness, high cost, and increasingly limited availability pose significant challenges for electronics. Crack-template (CT)-assisted fabrication has emerged as a promising technique to develop metal mesh-based TCEs with superior mechanical flexibility, high conductivity, and excellent optical transmittance. This technique leverages the spontaneous formation of random and continuous microcrack networks in sacrificial templates, followed by metal deposition (e.g., Cu, Ag, Al, etc.), to produce highly conductive, scalable, and low-cost electrodes. Various crack formation strategies, including controlled drying of polymer suspensions, mechanical strain engineering, and thermal processing, have been explored to tailor electrode properties. Recent studies have demonstrated that crack-templated TCEs can achieve transmittance values exceeding 85% and sheet resistances below 10 Ω/sq, with mesh line widths as low as ~40 nm. Moreover, these electrodes exhibit enhanced stretchability and robustness under mechanical deformation, outperforming ITO in bend and fatigue tests. This review aims to explore recent advancements in CT engineering, highlighting key fabrication methods, performance metrics across different metals and substrates, and presenting examples of its applications in optoelectronic devices. Additionally, it will examine current challenges and future prospects for the widespread adoption of this emerging technology. Full article

The central buckle is essential for maintaining longitudinal stability in suspension bridges. However, conventional steel buckles are often excessively stiff, leading to stress concentration and insufficient durability. Moreover, they tend to perform poorly under fatigue loading conditions. This study proposes a novel flexible central buckle system based on a Carbon Fiber-Reinforced Polymer (CFRP) to address these limitations. This study proposes a novel flexible central buckle system based on Carbon Fiber-Reinforced Polymer (CFRP) to address these limitations. Taking the long-span Shiziyang Suspension Bridge as a case study, a finite element model is developed to investigate the effects of CFRP central buckles with eight different stiffness levels on the static and dynamic responses of the bridge. The results indicate that a CFRP central buckle with a low elastic modulus achieves comparable displacement control performance to that of traditional steel buckles, while inducing significantly lower internal forces, demonstrating strong potential as a substitute. Based on this finding, a coordinated control strategy combining the CFRP central buckle with end-span restraining devices is proposed. This integrated system reduces midspan displacement and central buckle internal force by 61.1% and 49.8%, respectively. Considering both performance and cost-efficiency, a low-modulus CFRP material such as T300 is recommended. The proposed approach offers a new and effective solution for longitudinal control in ultra-long-span suspension bridges. Full article

Ammonia (NH₃) detection in liquids and biological fluids is essential for monitoring environmental contamination and industrial processes, ensuring food safety, and diagnosing health conditions. Existing detection techniques are often unsuitable for point-of-care (POC) use due to limitations including complex sample handling, lack of portability, and poor compatibility with miniaturized systems. This study introduces a proof-of-concept for a compact, portable device tailored for POC detection of gaseous ammonia released from liquid samples. The device combines a polyaniline (PANI)-based chemoresistive sensor with interdigitated electrodes and a resistance readout circuit, enclosed in a gas-permeable hydrophobic membrane that permits ammonia in the vapor phase only to reach the sensing layer, ensuring selectivity and protection from liquid interference. The ink formulation was optimized. PANI nanoparticle suspension exhibited a monomodal, narrow particle size distribution with an average size of 120 nm and no evidence of larger aggregates. A key advancement of this device is its ability to limit the impact of water vapor, a known source of interference in PANI-based sensors, while maintaining a simple sensor design. A tailored signal processing strategy was implemented, extracting the slope of resistance variation over time as a robust metric for ammonia quantification. The sensor demonstrated reliable performance across a concentration range of 1.7 to 170 ppm with strong logarithmic correlation (R² = 0.99), and very good linear correlations in low (R² = 0.96) and high (R² = 0.97) subranges. These findings validate the feasibility of this POC platform for sensitive, selective, and practical ammonia detection in clinical and environmental applications. Full article

Flexographic printing, traditionally used in the packaging industry, has emerged as a promising technology for microfluidic device fabrication due to enabling high resolution and being commercially available at a low cost compared to conventional techniques. This review explores the adaptation of a photopolymer flexographic printing plate mold (FMold) for microfluidics, examining its advantages, challenges, and applications. It offers a state-of-the-art view of the application of FMold for microfluidic systems, which offers a unique opportunity in terms of cost-effectiveness, scalability, and rapid prototyping. Applications are diverse: FMold has enabled the fabrication of microfluidic devices used in enhanced oil recovery to prepare rock-on-a-chip models, droplet generation and storage, suspension cell culture, monoclonal antibody production, complex cell differentiation pattern creation, phage screening, drug screening, cell detection, and cancer stem cell culture. Since its first appearance in 2018, FMold has been utilized in 50 publications in different laboratories around the world. Key advancements, current research trends, and future prospects are discussed to provide a comprehensive overview of this evolving tool. Full article

This study developed a novel pulsation-fluidized bed system, and the device was integrated into a reflux classifier to enhance the preconcentration of antimony oxide ore. The diaphragm-based pulsation device converts a stable upward water flow into a vertically alternating pulsation flow. By precisely controlling the pulsation parameters and optimizing operational conditions, the density-based stratification of particles can be significantly enhanced, thereby improving bed layering and effectively reducing entrainment. An antimony oxide ore from flotation tailings with an Sb grade of 0.8% was used as the feed material to evaluate the performance of the pulsation reflux classifier (PRC). Under optimized conditions, the PRC produced a concentrate with an Sb grade of 5.48% and a recovery of 81.68%, corresponding to a high separation efficiency of 70.97%. The response surface statistical model revealed that the interaction between the fluidization rate and pulsation frequency significantly enhanced the Sb grade of the concentrate, while pulsation stroke was identified as the key factor influencing separation efficiency. Furthermore, the variation in bed profile parameters with changing pulsation characteristics elucidates the interplay between particle suspension, stratification, and fluid disturbances. This study demonstrates that pulsation fluidization significantly enhances the separation performance of the reflux classifier, offering a new approach for the efficient preconcentration of complex fine-grained minerals. Full article

The terrain in hilly and mountainous areas is complex, and the level of agricultural mechanization is low. This article systematically reviews the research progress of key technologies for agricultural machinery power chassis in hilly and mountainous areas, and conducts an analysis of five aspects: the power system, walking system, steering system, leveling system, and automatic navigation and path tracking control system. In this manuscript, (1) in terms of the power system, the technical characteristics and application scenarios of mechanical, hydraulic, and electric drive systems were compared. (2) In terms of the walking system, the performance differences between wheeled, crawler, legged, and composite walking devices and the application of suspension systems in agricultural machinery chassis were discussed. (3) In terms of the steering system, the steering characteristics of wheeled chassis and crawler chassis were analyzed, respectively. (4) In terms of the leveling system, the research progress on hydraulic and electric leveling mechanisms, as well as intelligent leveling control algorithms, was summarized. (5) The technology of automatic navigation and path tracking for agricultural machinery chassis was discussed, focusing on multi-sensor fusion and advanced control algorithms. In the future, agricultural machinery chassis will develop towards the directions of intelligence, automation, greening, being lightweight, and being multi-functionality. Full article

Background: Vibrating mesh nebulizers (VMNs) are not only used to deliver typical pulmonary drugs but are also a promising platform for novel formulations and therapeutic applications. Typically, these devices operate continuously or on demand and are directly connected to the outflow interface (mouthpiece or mask) without valving systems that could spare the drug during exhalation. This paper examines the possibility of increasing the delivery of inhaled budesonide aerosol by attaching a valved holding chamber (VHC) to selected VMNs. Methods: A laboratory in vitro study was conducted for seven budesonide (BUD) nebulization products (0.25 mg/mL). The rates of aerosol delivery from VMNs alone or VMN + VHC systems were determined gravimetrically for a simulated breathing cycle, while droplet size distributions in mists were measured by laser diffraction. Results: The VMN + VHC systems increased the amount of aerosol available for inhalation and the fraction of fine particles that could penetrate the pulmonary region. Depending on the VMN and BUD product, a relative increase of 30–300% in the total drug delivery (T) and 50–350% in the pulmonary drug availability (P) was obtained. The results are explained by the reduction in aerosol losses during exhalation (the fugitive emission) by the VHC and the simultaneous elimination of the largest droplets due to coalescence and deposition in the chamber. Both VMN and BUD affected the aerosol’s properties and discharge mass and thus the actual benefits of the VHC. Conclusions: While the results confirm the superiority of VMN + VHC over VMNs alone in nebulizing BUD suspensions, they also show that it is difficult to predict the effects quantitatively without testing the individual nebulizer–chamber–drug combination. Full article

Inertial microfluidics has gained significant attention for cell counting applications due to its simplicity, high throughput, and precision. This study utilized an inertial flow microfluidic device to count blood cell-sized microparticles, simulating normal and diseased conditions. The device could focus on and count cells sized between 7 µm and 16 µm while being observed under optical microscopes, with controlled flow rates from 1 to 15 µL/min. Suspensions of cells with ratios of 600:1 for normal conditions and 400:1 for diseased conditions were studied in microchannels at different flow rates. The methodology for counting involved using a syringe pump for precise flow actuation and employing an image-based particle counting technique through optical microscopy, utilizing the passive technique of inertial microfluidics. Results were compared using two optical microscopes across both suspension types. The key findings showed that at a 600:1 ratio of 8 µm and 15 µm cells, counts of 6.45 × 10⁷ cells/mL and 1.10 × 10⁷ cells/mL, respectively, while in the 400:1 ratio of both cells, counts of 4.5 × 10⁷ cells/mL and 2.16 × 10⁷ cells/mL, respectively, were achieved at optimal parameters. This study employed an inertial flow microfluidic device to count microparticles the size of blood cells. We assessed the counting performance using optical microscopy at two different cell ratios and validated our results against hemocytometer counts. Our findings demonstrate that the channel size 150 µm and the flow rate at 1 µL/min provided the optimal counting accuracy for both particle sizes. This device offers an efficient and adaptable solution for accurate multi-cell counting under optimized conditions and supporting applications in resource-limited medical diagnostics. Full article

The paper analyzes the transport capabilities of energy-efficient resonant conveyors, with a particular emphasis on their dosing capabilities. They are driven by an additional mass—acting as a resonator—using a relatively small vibrator whose forcing power constitutes about 20% of the force that would be needed to drive a similar conveyor of classical construction and the same transport capacity, resulting in lower energy demand. These conveyors have been present since the 1950s, but their widespread use occurred with the proliferation of cheap and easily controllable frequency inverters. In the paper, using a relatively simple model that allowed for the determination of amplitude–frequency characteristics and the dependence of transport speed on the forcing frequency, the impact of the resonator mass value on the device’s operation was shown. It was demonstrated that the value of this mass should be similar to the mass of the transporting trough, which increases the durability of the drive as well as the durability of the suspension between the trough and the resonator. A larger resonator mass also positively affects the dosing capabilities of the device and its energy efficiency during the dosing process with frequent transport stops. Full article

This paper reports several preliminary investigations concerning the relative humidity (RH) detection response of a chemiresistive sensor that uses a novel sensing layer based on pristine carbon nano-onions (CNOs) and polyvinyl alcohol (PVA) at a 1/1 and 2/1 w/w ratio. The sensing device, including a Si/SiO₂ substrate and gold electrodes, is obtained by depositing the CNOs–PVA aqueous suspension on the sensing structure by drop casting. The composition and morphology of the sensing film are explored by means of scanning electron microscopy, Raman spectroscopy, atomic force microscopy, and X-ray diffraction. The manufactured sensor’s room temperature RH detection performance is examined by applying a continuous flow of the electric current between the interdigitated electrodes and measuring the voltage as the RH varies from 5% to 95%. For RH below 82% (sensing layer based on CNOs–PVA at 1/1 w/w ratio) or below 50.5% (sensing layer based on CNOs–PVA at 2/1 w/w ratio), the resistance varies linearly with RH, with a moderate slope. The newly developed sensor, using CNOs–PVA at a 1:1 ratio (w/w), responded as well as or better than the reference sensor. At the same time, the recorded recovery time was about 30 s, which is half the recovery time of the reference sensor. Additionally, the changes in resistance (ΔR/ΔRH) for different humidity levels showed that the CNOs–PVA layer at 1:1 was more sensitive at humidity levels above 80%. The main RH sensing mechanisms considered and discussed are the decrease in the hole concentration in the CNOs during the interaction with an electron donor molecule, such as water, and the swelling of the hydrophilic PVA. The experimental RH detection data are analyzed and compared with the RH sensing results reported in previously published work on RH detectors employing sensing layers based on oxidized carbon nanohorns–polyvinylpirrolidone (PVP), oxidized carbon nanohorns–PVA and CNOs–polyvinylpyrrolidone. Full article

Efficient oil transportation in field-deployed mobile pipelines is critical, but mixed-oil zones at interfaces reduce quality and increase waste, necessitating effective interface detection and cutting. Existing online densitometers, such as vibrating tube or high-accuracy magnetic suspension types, typically require external power, limiting their use in remote or emergency/temporary field operations. A self-powered device is presented that leverages gravitational force variations acting on a float to detect density changes and trigger automatic cutting. Validated with gasoline, diesel, kerosene, and water, it achieves a 10 kg/${\mathrm{m}}^3$ resolution, deemed sufficient for functional batch separation in its target application, with switching times of 61–395 s for density differences (760–835 kg/${\mathrm{m}}^3$). It supports 20–90% blending ratios, with a vent mitigating gas effects. The modular, robust, self-powered design suits emergency operations, offering a practical alternative to powered systems. Future work targets improved resolution and environmental testing. Full article

This study presents the fabrication and characterization of magnetically active textiles using cotton fibers impregnated with suspensions of pumpkin seed oil, carbonyl iron microparticles, and propolis microparticles. The textiles were utilized to manufacture planar capacitors, enabling an investigation of the effects of static magnetic fields and the introduced microparticles on the components of complex dielectric permittivity. The results reveal that the dielectric properties of the fabricated textiles are highly sensitive to the applied magnetic field intensity, the frequency of the alternating electric field, and the composition of the impregnating suspension. The experimental findings suggest that the dielectric loss and permittivity can be finely tuned by adjusting the magnetic flux density and the proportion of propolis microparticles. The multifunctional nature of these magnetically responsive textiles, combined with the bioactive properties of the incorporated natural components, opens promising pathways for applications in smart textiles, biomedical devices, and sensor technologies. Full article