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Cryo-adsorption is an attractive method for hydrogen storage. However, the non-uniformity of temperature during the charging process affects its performance. To improve the uniformity of the temperature field inside the hydrogen storage tank, and thus improve the hydrogen storage performance and hydrogen storage efficiency of the tank, this paper proposed a thermal management method that combines the central and spiral cooling tubes with vacuum adiabatic heat management. Accordingly, a numerical model was built to investigate the hydrogen adsorption performance of the installation. The results reveal that satisfactory temperature-uniformity was shown in charging and dormant stages. Suitable operating conditions also can improve hydrogen storage performance by reducing the impact of thermal effects. Moreover, the hydrogen storage capacity of activated-carbon cryo-adsorption is roughly 2.5 times that of cryo-compressed storage and 10 times that of ambient-compressed storage. [Display omitted] • A new cooling structure enhancing temperature uniformity was proposed. • The charge cycle of cryogenic activated carbon hydrogen storage is simulated. • Hydrogen storage capacity is significantly improved with new cooling structure. • Proper operating condition leads to satisfactory hydrogen storage amount. [ABSTRACT FROM AUTHOR]

This paper developed a method for more accurate permittivity extraction of high-loss materials using the waveguide method to reduce the effect of the air gap. This method improves the Baker-Jarvis algorithm. It makes the errors of S-parameters caused by the air gap compensated by a correction factor β of the form: (S21 + S12) + β(S11 + S22). In our study, the correction results of β for materials on different frequencies and air gap sizes are quantitatively investigated. Furthermore, we propose a method to obtain an optimal frequency-independent β for different materials. A typical high-loss BeO-SiC ceramic commonly used in vacuum electron tubes is analyzed and discussed in detail. It shows that compared to traditionally utilizing only S21 (β = 0), adopting an optimal β can reduce the average errors of the complex permittivity from 17.7% to 7.9% with a 0.10 mm air gap. The proposed method is verified by measurements of unshaved and shaved samples. [ABSTRACT FROM AUTHOR]

The global impact of climate changes due to greenhouse gas emissions cannot be overemphasized. To combat this, engineers are striving to develop innovative enhancements for heat transfer and fouling reduction in process equipment as a pathway to reduce CO2 emissions. A novel surface application of Minimox® treatment, a water-based suspension of rare-earth oxides, is a promising solution. The self-protective alloy treatment, unlike a traditional continuous coating, has no measurable thickness, does not impose any operating temperature limits, protects from high temperature oxidation, and decreases surface energy and polarity that leads to low fouling and coking rates. Minimox can be applied by dipping or spraying to both external and internal surfaces, including non-conventional tubing shapes. A post-application curing at 400 °C for 1 h is needed to ensure maximum fouling mitigation efficacy. Laboratory tests conducted to simulate operating conditions in a Coker furnace show that the Minimox-treated tubes reduce coke formation by about 80% as compared to untreated tubes. In addition, adhesion of coke to the Minimox treated tubes was significantly lower than for the untreated tubes. Field data collected in refinery applications involving Coker furnace tubes and a vacuum column wash bed are promising, lending support the laboratory results. [ABSTRACT FROM AUTHOR]

This paper presents an analytical method for the dimensioning and selection of the four glass tube collector types: single-glazed with an air layer, single-glazed with a vacuum layer, double-glazed with an air layer, and double-glazed with a vacuum layer. In the first part of the paper (dimensioning phase), the iterative thermal resistance calculation algorithms were developed for all glass tube collector types, whereby the iterative thermal resistance calculation algorithm of the single-glazed tube collector with an air layer was experimentally tested and validated. The second part of the paper (selection phase) uses a multi-criteria decision-making method to determine the optimal glass tube collector design. Unlike other papers, three indicator groups are taken into account in this case: geometric (mass, surface occupation, total surface occupation, volume occupation), economic (manufacturing and exploitation costs), and ecological (embodied energy and greenhouse gas emission). The proposed method is characterized by simple and fast calculations with satisfactory accuracy, which avoids high investment costs (experimental research), approximation and discretization of physical models (numerical research), and a large number of input parameters with boundary conditions (theoretical research). It should be noted that, with certain additions and changes, it can also be applied to other solar thermal collectors, so the authors believe such tools are handy for the global scientific public. [ABSTRACT FROM AUTHOR]

Electrical and electronic components, the silent orchestrators of our technological symphony, have been crucial for enabling societal advances. From the simple beginnings of vacuum tubes to the complex circuitry in today's smartphones, the role and type of electronic components have continued to evolve. The components of electrical and electronic equipment once it has reached the end of its useful life as a product are called electronic waste (e-waste). The exponential growth of electronic devices has made e-waste management an important environmental issue. Improper disposal of e-waste to landfills has serious environmental consequences for the global ecosystem. The majority of discarded e-waste such as computers, mobile phones, televisions, printers, and so on, are embedded with printed circuit boards (PCBs), which are an essential and basic component. PCBs of e-waste contain many different metals including precious metals (Ag, Au, Pd, Pt, etc.), critical elements (Li, Ni, Ga, graphite, rare earth elements, etc.) and non-critical metals (Al and Fe) in varying percentages depending on the electronics. In the emerging era of circular economy recycling, waste printed circuit boards (wPCBs) of any e-waste are seen as an alternative to processing mining ores to meet future metals demand. Different recycling methods such as mechanical separation, pyrometallurgy, hydrometallurgy, biohydrometallurgy, pyrolysis, electrolysis and supercritical fluid technologies have been explored to extract the valuable metals from e-waste. This article aims to provide a critical review of the different recycling routes for e-waste, with a focus on the emerging supercritical fluid technologies (SFT), and their opportunities and challenges. This review will compare the emerging SFTs for existing processes used in industry and other alternative treatment methods. The specific areas of comparison include technical complexity and environmental impacts. [ABSTRACT FROM AUTHOR]

Deepwater oil and gas wells have complex well body structure, and the multi-layer closed annulus structure formed by free section and sealed section tubing column is easy to absorb heat and generate expansion pressure. In deepwater drilling operation, the rise in temperature of the closed casing annulus is easy to produce the phenomenon of rising annulus pressure, and due to the special characteristics of the underwater wellhead device, it is not possible to release the annulus pressure between the casing, and the high annulus pressure will lead to casing extrusion and deformation, which will seriously threaten the safety and integrity of the wellbore. In order to ensure the smooth progress of deepwater drilling operations and reduce operational risks, corresponding methods and strategies are proposed for the management of annulus pressure in deepwater oil and gas wells. A variety of measures and products have been developed worldwide for engineering measures of annulus pressure management, including optimization of well structure and cementing design, use of rupture discs, foam casing and vacuum tubing, and other measures. This paper analyzes five major categories of prevention methods and control techniques for deepwater oil and gas wells well annulus confinement pressure, which are increasing casing strength (stiffness level, wall thickness), eliminating expanding fluid, blocking heat transfer, balancing fluid thermal expansion and releasing annulus confinement pressure management strategies. Measures to control annulus pressure by increasing casing strength (stiffness level, wall thickness), fully sealing the annulus, vacuum insulated tubing, foam casing, nitrogen foam isolation fluid, non-circumferential pipe shoes and rupture disc casing tools and analyzing their engineering advantages and disadvantages. According to the engineering application experience, the use of rupture disk casing tool to alleviate the annular pressure is currently the most widely used and stable and reliable means in the world. And according to the theoretical knowledge and engineering practice of annular pressure management, the basic strategy of annular pressure management is summarized when rupture disk is adopted as the main means of annular pressure management. [ABSTRACT FROM AUTHOR]

The geotechnical tube technology has been widely used in the dewatering treatment of high-water-content slurries, such as engineering waste muds, mine water sludges, and dredging slurries. However, the existing engineering practice adopting the traditional geotextile tubes is characterized by low efficiency and difficult quality control. To address these issues, a new approach was developed by combining the geotextile tubes and vacuum preloading technology. In this method, several plastic drain boards were embedded in a geotextile tube as prefabricated horizontal drains (PHDs), and a vacuum was applied to promote drainage. The effectiveness of the proposed method was verified by a comparison test. A two-dimensional plane-strain analytical consolidation problem with a distributed drainage boundary was then formulated and solved to predict the consolidation process of soil in a vacuum preloaded geotextile tube. The analytical solution was validated against the results of a pilot field test, and then the influence of PHD spacing on the consolidation process was also discussed. Compared to the traditional geotextile tubes, the approach proposed in this paper promises good applicability and can effectively shorten the treatment time by 73.3% and reduce the water content of treated soils by 51.9%. [ABSTRACT FROM AUTHOR]

A novel test setup called the asymmetric shock tube for experiments on nonideal rarefaction waves (ASTER) has been commissioned at Delft University of Technology. The ASTER, which works according to the principle of Ludwieg tubes, is designed to generate and measure the speed of small and finite amplitude waves propagating in the dense vapors of fluids formed by complex organic molecules, therefore in the nonideal compressible fluid dynamics regime. The ultimate goal of the associated research is to prove the existence of nonclassical gasdynamics. The setup consists of a high-pressure charge tube and a vacuum tank separated by a glass disk equipped with a breaking mechanism for rarefaction waves experiments. When the glass disk is broken, an expansion wave propagates into the tube in the direction opposite to the fluid flow. The propagation speed of this wave is measured using a time-of-flight method with the help of four fast-response pressure sensors placed equidistantly in the middle of the tube. The charge tube can withstand pressures and temperatures of up to 15 bar and 400 ∘ C . Preliminary rarefaction experiments were successfully conducted using dodecamethylcyclohexasiloxane, D 6 , as the working fluid and at pressures and temperatures of up to 9.4 bar and 372 ∘ C , respectively. The results of an experiment featuring the initial state for which a theoretical model predicts the nonclassical acceleration of rarefaction waves show that the propagation is qualitatively different from that put into evidence by experiments for which the propagation is classic. Upcoming setup improvements and experimental campaigns are planned with the objective of experimentally verifying the existence of nonclassical gasdynamics. [ABSTRACT FROM AUTHOR]

GeSn has attracted increasing attention due to its tunable bandgap from indirect to direct resulting in unique electronic and optoelectronic capabilities. Chemical vapor deposition (CVD) is well acknowledged as an advanced growth method for GeSn, demonstrating its capability with grown materials for infrared lasers and detector development. As an in situ diagnostics of the CVD process, a residual gas analyzer (RGA) could enable the detection of all gaseous species during growth, thus probing the growth dynamics and mechanism. Therefore, it is highly desirable but is lacking in the (Si)GeSn research community. This work utilized an RGA equipped with a specialized differential vacuum pumping system to analyze the mass spectra of the GeSn CVD precursors of SnCl4, GeH4, and their combination. The spectra of SnCl4 collected from gas samples at a standard base pressure of 0.3 Torr display consistent fragments with central mass-to-charge ratios (m/z) of 78, 120, 155, 225, and 260, corresponding to Sn+, SnCl2+, SnCl+, SnCl2+, SnCl3+, and SnCl4+, respectively. These profiles closely resemble those observed in the National Institute of Standards and Technology and Wiley and Matsumoto et al. The simultaneous introduction of SnCl4 and GeH4 at a combined pressure of several tens of Torr yields spectra, indicating a chemical reaction that produces GeCl4 at room temperature in the vacuum chamber and tubing. Utilizing Gaussian16 and ORCA codes, the ab initio and density functional thermochemistry computations were employed to predict potential essential reactions and validate the experimental findings. [ABSTRACT FROM AUTHOR]

Advancing the development of point‐of‐care testing (POCT) sensors that utilize interstitial fluid (ISF) presents considerable obstacles in terms of rapid sampling and analysis. Herein, an innovative strategy is introduced that involves the use of a 3D‐printed, hollow microneedle array patch (MAP), in tandem with a vacuum tube (VT) connected through a hose, to improve ISF extraction efficiency and facilitate expedited analysis. The employment of negative pressure by the VT allows the MAP device to effectively gather ≈18 µL of ISF from the dermis of a live rabbit ear within a concise period of 5 min. This methodology enables the immediate and minimally invasive measurement of glucose levels within the body, employing personal healthcare meters for quantification. The fusion of the VT and MAP technologies provides for their effortless integration into a comprehensive and mobile system for ISF analysis, accomplished by preloading the hose with custom sensing papers designed to detect specific analytes. Moreover, the design and functionality of this integrated VT‐MAP system are intuitively user‐friendly, eliminating the requirement for specialized medical expertise. This feature enhances its potential to make a significant impact on the field of decentralized personal healthcare. [ABSTRACT FROM AUTHOR]

In this article, an experiment has been carried out with heat pipe vacuum or evacuated tube collector to produce water from atmospheric air. In this experiment, the regeneration and adsorption method has been adopted, that is, water has been produced through the adsorption and regeneration of desiccants. The desiccant is heated through a hot surface to facilitate its regeneration. Limited experiments have been conducted to obtain water through the regeneration of desiccant using a hot surface. For the condensation of water vapor, a novel box has been designed, named the "novel‐designed acrylic box." The water is collected in a measuring flask or beaker to determine its quantity. Silica gel desiccant has been used for the adsorption and regeneration of water vapors. In this experiment, the adsorption process for silica gel was carried out in two different ways. In the first method, 1 kg of silica gel was scattered on the copper tray, that is, inside the system, while in the second method, 1 kg of silica gel was scattered on the paper, that is, outside of the system. In the first case silica gel adsorbed 137 g water vapor, and in the second case, it adsorbed 232 g water vapor. In the first case of adsorption, 70 mL water was produced while in the second case of adsorption, 175 mL water was produced from ambient air. The system's maximum efficiency was found to be 4.9%. Effects of various parameters, such as solar intensity, ambient temperature, wind speed, and so forth, have been studied. [ABSTRACT FROM AUTHOR]

Solar distillation has gained more importance as a practical and environmentally friendly solution for converting non-potable water into clean water using solar energy, in response to the increasing concern about the scarcity of clean water. In the city of Kirkuk, Iraq, located at 35.4666° N, 44.3799° E, we conducted an experiment to enhance the efficiency of a conventional solar distiller with a surface area of 1 m². To enhance evaporation, we incorporated 8 vacuum tubes. For improved condensation, we conducted experiments using two different cooling methods to cool the glass cover: pulse cooling (1min/15min), (1min/10min) and continuous cooling. Based on the trial findings, the productivity reached 2653 ml/day, representing a 237.5% increase in production. When vacuum tubes were attached to the solar still, the productivity increased compared to a conventional distiller. With a cooling time of (1min/15min), the productivity reached 3510 ml/day. With a cooling(1min/10min), the productivity reached 3587ml/day. When constantly cooling, the productivity reached 4980 ml/day. The productivity experienced respective increases of 332%, 386%, and 656.8% in comparison to the conventional distiller. The modified still's thermal efficiency was 21.6%, 24.6%, and 37.7%, compared to 17% for the conventional system and 18.8% for the improved system without glass cover cooling. [ABSTRACT FROM AUTHOR]

Thin films of cobalt (about 20 nm) were deposited on a silicon ⟨ 100 ⟩ substrate. The deposition was carried out using the e-beam technique. The films were oxidized under two different conditions: in vacuum and in a quartz tube furnace. The elemental cobalt and the two oxidized samples were characterized by the technique of x-ray photoelectron spectroscopy. Magnesium Kα radiation (1253.6 eV) was used as the source of the x-ray excitation. The spectral data in the cobalt 2p, 2s, 3s, 3p, Auger LMM regions, oxygen 1s region, and carbon 1s regions were recorded under a high resolution mode. The sample oxidized in vacuum showed features distinct from that oxidized in the quartz tube furnace. The data will serve as a comparison for the cobalt oxides formed under different processing conditions. [ABSTRACT FROM AUTHOR]

Glass-to-metal seals are a very important element in the construction of vacuum tubes, electric discharge tubes, pressure-tight glass windows in metal cases, and metal or ceramic packages of electronic components. This paper presents the influence of different pretreatment methods on the high-temperature wettability of 304 stainless steel by high-alumina glass sealing. The pretreatment of the steel included laser surface melting and pre-oxidizing. The bonding characteristics of glass and stainless steel directly depend on the wettability in terms of the measured wetting angle, the type of oxide formed at the stainless steel surface, and the microstructural changes during the manufacturing process. The oxide film thickness on the stainless steel surface was evaluated to determine the optimal parameters. The film was wetted with high-alumina glass powder at different temperatures. The results showed that pre-oxidation decreased the wetting angle from 56.2° to 33.6°, while for the laser-melted surface, the wetting angle decreased from 49.8° to 31.5°. Scanning electron microscopy (SEM) revealed that the oxide film on the laser-melted surface was thicker and denser than that formed on the pre-oxidized surface. The present work shows that laser surface melting has a greater beneficial influence on the wetting and diffusion characteristics of 304 stainless steel sealed by high-alumina glass. [ABSTRACT FROM AUTHOR]

In this study, a novel system which integrates solar thermal energy with membrane gas absorption technology is proposed to capture CO2 from a 580 MWe pulverized coal power plant. Technical feasibility and economic evaluation are carried out on the proposed system in three cities with different solar resources in China. Research results show that the output capacity and net efficiency of the SOL-HFMC power plant are significantly higher than those of the reference power plant regardless of whether a TES system is applied or not. In addition, the CEI of the SOL-HFMC power plant with the TES system is 4.36 kg CO2/MWh, 4.45 kg CO2/MWh and 4.66 kg CO2/MWh lower than that of the reference power plant. The prices of the membrane, vacuum tube collector and phase change material should be reduced to achieve lower LCOE and COR values. Specifically for the SOL-HFMC power plant with the TES system, the corresponding vacuum tube collector price shall be lower than 25.70 $/m2 for Jinan, 95.20 $/m2 for Xining, and 128.70 $/m2 for Lhasa, respectively. To be more competitive than a solar-assisted ammonia-based post-combustion CO2 capture power plant, the membrane price in Jinan, Xining and Lhasa shall be reduced to 0.012 $/m, 0.015 $/m and 0.016 $/m for the sake of LCOE, and 0.03 $/m, 0.033 $/m and 0.034 $/m for the sake of COR, respectively. [ABSTRACT FROM AUTHOR]

Despite the large variety of high-voltage semiconductor components for medium and high voltage switching and pulse-forming applications as well as for high-power high-frequency generation, the use of vacuum electron tubes still prevails to a considerable degree. Due to the common design incorporating a high energy electron beam which finally is dumped into an anode or a resonator cavity, these tubes are also considered as sources of X rays produced as bremsstrahlung and characteristic radiation, which are referred to as parasitic X rays. Here three types of vacuum-electron tubes, diode, tetrode, and thyratron, with glass housings are investigated. They are predominantly operated in the high voltage range below 30 kV and are not subject to licensing laws. The measurements of the dose rate and X-ray-spectra were performed in the laboratory without complex electrical circuitry usually used in making practical measurements for occupational radiation protection. For the diode tube, where a parasitic X-ray emission is observed only in the reverse operation as a blocking diode, a broad distribution of dose rates of electrically equivalent specimens was observed. This is attributed to field emission from the electrodes. For the tetrode and the thyratron tubes, field emission from the electrodes is identified as the dominant mechanism for the generation of parasitic X rays. Thus, technical radiation protection must focus on shielding of the glass tube rather than optimization of the electrical circuitry. [ABSTRACT FROM AUTHOR]

Treating the high water-content sludge with vacuum-assisted prefabricated horizontal drains (PHDs) placed inside, geotextile tubes have the advantage of multiple drainage paths, and geomembrane tubes have the superiority of high vacuum maintenance. Therefore, converting the geotextile tube into a geomembrane tube during slurry dewatering is an effective measure for greater dewatering efficiency and better dehydration effect. In this study, a profound plane-strain consolidation model considering two-dimensional seepage is developed for explaining the dewatering mechanism of sludge in the geo-tubes. Analytical solutions are given and validated by the experiment. The impact of major variables on tube efficiency is further discussed to reference the practice design. Parametric analyses reveal the critical time corresponding to the optimal efficiency of the geotextile tube, after which its consolidation efficiency decreases significantly. However, the consolidation efficiency of a geomembrane tube increases throughout the duration. Consequently, a switching point corresponding to the iso-efficiency state of the geotextile tube and geomembrane tube can be determined for the tube conversion. [ABSTRACT FROM AUTHOR]

A novel design methodology based on a current-tunable magnetic focusing system that can flexibly switch between Brillouin and immersive flow focusing modes is presented in this paper. Such a magnetic system, which comprises cascaded solenoid coils and pole pieces, could be used in beam optics systems of vacuum tubes, particle accelerators, and free-electron lasers. Although the profile of this magnetic system is not brand new, the novel way proposed in this paper to establish and manipulate such a system to fit versatile purposes has never been reported in the literature to the best of the authors' knowledge. The specific structure of the magnetic system should be optimized, starting from the immersive flow focusing mode together with the electron gun design, which will be determined on successful optimization. According to our analysis, such systems could be transformed into the Brillouin bunching mode by simply adjusting the coil currents without modifying the hardware. To verify such an approach, single-beam and multi-beam optical systems are demonstrated in this paper. Moreover, the beam radius in such systems could also be conveniently adjusted via a similar technique. [ABSTRACT FROM AUTHOR]

A recovery system for an automatic spraying robot to conduct the spraying operation outdoors for ships is designed in this paper, which addresses the pollution problem of volatile organic compounds (VOCs) by employing the vacuum recovery method. The recovery system consists of the recovery hood, nozzle, and vacuum tubes. The recovery hood is the critical part of the recovery system and is designed with internal and external cavities, as well as four vacuum tubes for recycling VOCs. Based on the computational fluid dynamics (CFD) method, simulation in the time domain of the gas–liquid interaction, droplet evaporation, and wall impingement is conducted. To identify the better recovery performance, three vacuum recovery-hood schemes are designed, and their performance is compared. The numerical results show that the distance between the vacuum tubes and the intake gap has a significant impact on the VOCs' recovery effect. One of the main reasons for the escape of VOCs is that the swirling airflows in the baffle plane act as vortices which may capture VOCs, causing the accumulation of VOCs beyond the capacity of the external cavity. Dividing the external cavity into four chambers with deflectors (with each chamber equipped with one vacuum tube only) can significantly reduce the leakage rate of the recovery system. The recovery system provides a theoretical solution for implementing the prevention and control of VOCs in shipyards as soon as possible. [ABSTRACT FROM AUTHOR]

In this paper we consider a generalization of the coupon collector problem where we assume that the set of available coupons consists of standard coupons and an additional penalty coupon, which does not belong to the collection and interferes with collecting standard coupons. Applying Markov chain approach the following problem is solved: how many coupons (on average) one has to purchase in order to complete a collection without interference or to collect n more penalty coupons than standard coupons. Also, we obtain additional results related to the distribution of the waiting time until the collection is sampled without interference or until n more penalty coupons than standard coupons is sampled. [ABSTRACT FROM AUTHOR]

Splashing of impacting drops produces a myriad of secondary spray droplets, which generate aerosols during rain on the ocean and can cause health hazards during the spraying of pesticides or enhance the droplet transmission of disease. Determining the size and number of the finest splashed droplets is therefore of practical interest. Herein, we use a novel experimental facility with a 26m tall vacuum tube, to study well-controlled drop impacts at velocities as high as 22ms-1, where we reach parameter regimes not studied before using freely falling drops. Using extreme video frame rates, we pinpoint the primary source of the finest spray, coming from the catastrophic bending and rupture of the sub-micron-thick ejecta sheet, which emerges at a high speed from the neck connecting the drop and pool. The axisymmetric bending and convoluted ejecta shapes are driven primarily by resistance from the surrounding air, but also depend on the viscosity difference between drop and pool, which influences the initial ejection angle of the sheet. These extreme impact conditions provide new insights into general spray formation, through a sequence of bucklings of the rising ejecta, which dances next to the drop surface and can also form an enclosed air torus. [ABSTRACT FROM AUTHOR]

On a worldwide basis, freshwater is becoming increasingly limited, particularly in dry and distant regions. This presents a complex problem for regions such as islands, where the transportation of water that is suitable for drinking is expensive. In order to address this dilemma, the primary focus of the 21st century ought to be on boosting water purification through the use of renewable energy technology in the desalination industry. To be more specific, the incorporation of solar energy into the business has the potential to extend the lifespan of units, reduce expenses, and reduce the positive impact on the environment. The article contains a sufficient number of studies on a variety of passive and active stills, and it offers an understanding of the effectiveness of each form of still. Vacuum tube solar stills are more efficient than others. In addition to this, it investigates several approaches to cooling the glass cover and the elements that influence the productivity of solar stills, among which are environmental and design considerations. Resolving the problem of diminishing freshwater resources and integrating solar energy for water purification. [ABSTRACT FROM AUTHOR]

This paper shows the development of a numerical analysis model, which enables the calculation of the cargo transport capacity of a vehicle that circulates through a vacuum tube at high speed, whose effectiveness in transport is analyzed. The simulated transportation system is based on vehicles moving in vacuum tubes at high speed, a concept commonly known as Hyperloop, but assuming the vehicles for cargo containers. For the specific vehicle proposed, which does not include a compressor and levitates on magnets, the system formed by the vehicle and the vacuum tube has been conceptually developed, establishing the corresponding mathematical relationships that define its behavior. To properly model the performance of this transport system, it has been necessary to establish the relationships between the design variables and the associated constraints, such as the Kantrowitz limit, aerodynamics, transport, energy consumption, etc. Once the model was built and validated, it was used to analyze the effects of the variation of the number of containers, the operating speed and the tube length, considering the total and specific consumption of energy. After finding the most efficient configuration regarding energy consumption and transport effectiveness, the complete system was calculated. The results obtained constitute a first approximation for the predesign of this transport system and the built model allows different alternatives to be compared according to the design variables. [ABSTRACT FROM AUTHOR]

Hot water production using solar collectors is the utmost comprehensive application of solar energy. Solar water heaters are still incapable of operating in night/off-weather conditions and lacking in thermal performance. Researchers can see heat storage (thermal battery backup) as a potential solution. The novelty of this study is the fabrication and testing of newly designed U-pipe-based vacuum tube collectors (VTCs) integrated with thermal energy storage. Furthermore, Stearic acid and PEG6000 were selected as phase change materials in this study, and collectors were operated in closed mode for specially designed cases. Also, a cost analysis was evaluated for these collectors to show their economic viability. The thermal performance and economic outcomes of storage-based collectors were compared with conventional collector. Measured experimental data encompassed instantaneous inlet and outlet water temperatures, solar radiation and ambient temperature. The empirical findings showed that the maximum daily thermal performances were 69.81, 68.34%, and 61.33% obtained by stearic acid-filled collector-2, followed by PEG-filled collector-3 and conventional collector-1 at .334 LPM for case-III, respectively. Moreover, the maximum energy enhancement ratio was 6.28% for collector-2 and 6.21% for collector-3 at .5 LPM for case-II, respectively. From the economic analysis results, it was observed that the modified solar water heaters (collector-2 and collector-3) have an average levelized water heating cost of .06885 $/kWh and .06818 $/kWh, respectively, with a payback time of 5.37 and 5.15 years, which makes the modified collectors economically viable. Finally, the results indicate that the storage-based collectors can be used for applications with specific temperatures of hot water. [ABSTRACT FROM AUTHOR]

Low temperature superconducting vacuum tube maglev is one of the ultra-high-speed transportation methods that a lot of countries are competing to develop. At present, the research is in its infancy, and it is necessary to evaluate the dynamic performance of its route lines. In this paper, taking the maglev test line from Changsha to Hengyang as an example, a vehicle-route coupling model of the low-temperature superconducting electric levitation system was established, the dynamic performances of the maglev vehicle were determined. Firstly, the vertical and lateral acceleration of the carbody, levitation and guidance force were calculated. Secondly, the frequency histograms of the dynamic performance indicators were drawn, and the distributions of these indicators in different intervals was analyzed. Thirdly, the influence of the different curve radius on the dynamic performance index was obtained. The research shows that when the maglev vehicle travels across the Changsha-Hengyang line, the calculated vertical and lateral accelerations of the carbody are lower than the comfort threshold, and the dynamic performance meets the requirements. From the perspective of vehicle dynamic performance, the transition curve length of 1 400 m is reasonable. When the curve radius is 20 000 m, the vehicle speed 1 000 km/h and the cross slope of 16° match the best dynamic performances. The results in the article can provide references for the design of ultra high speed maglev lines. [ABSTRACT FROM AUTHOR]

This paper explores the operation mechanism of the superjunction structure in RC-IGBTs based on carrier distribution and analyzes the advantages and challenges associated with its application in RC-IGBTs for the first time. A Partial Schottky Collector Superjunction Reverse Conduction IGBT (PSC-SJ-RC-IGBT) is proposed to address these issues. The new structure eliminates the snapback phenomenon. Furthermore, by leveraging the unipolar conduction of the Schottky diode and its fast turn-off characteristics, the proposed device significantly reduces the turn-off power consumption and reverse recovery charge. With medium pillar doping concentration, the turn-off loss of the PSC-SJ-RC-IGBT decreases by 54.1% compared to conventional superjunction RC-IGBT, while the reverse recovery charge is reduced by 52.6%. [ABSTRACT FROM AUTHOR]

In this study, a solar-Organic Rankine Cycle (ORC) assisted hydrogen production system was experimentally investigated. An evacuated tube heat pipe solar collector (ETHPSC) was used for thermal energy generation. The tubes used in this study were produced differently from the tubes of the conventional heat pipe. The condenser area of the vacuum tubes used was made of glass instead of copper. Moreover, acetone was used as the fluid in the tube. The thermal energy obtained from the collector was used as a heat source for electrical energy in the ORC system. A uniquely designed ORC system is modeled and manufactured. The electrical energy obtained from the ORC unit was used for hydrogen production by means of the proton exchange membrane electrolyzer (PEMe). As a result of the study, two different efficiency analyses were made. If all of the electricity produced in the S-1 scenario was spend on hydrogen production, the energy and exergy efficiency were calculated as 3.45% and 2.15%, respectively. In the S-2 scenario, if some of the electricity produced was spend on hydrogen production, the energy and exergy efficiency of the whole system were found to be 0.01446% and 0.002146% respectively. In addition, 0.000004433 kg/s hydrogen production was obtained from the presented system. • Novelty solar-ORC based hydrogen production system is performed. • The energy efficiency of the S-1 integrated system was determined as 3.45%. • The energy efficiency of the S-2 integrated system was determined as 0.01446%. • Hydrogen production was calculated as 0.000004433 kg/s. [ABSTRACT FROM AUTHOR]

Alumina ceramics are widely used to fabricate the insulating tubes of vacuum electronic devices. The long-term stress borne by ceramics during service may lead to failure, so it is of great significance to investigate the mechanical reliability of ceramics. Annealing is a commonly used step in the processing of an alumina ceramic, which may affect its mechanical performance. Herein, the effects of inter-granular crystalline phase induced by annealing on the service reliability of a 95% alumina ceramic are studied, and the mechanisms are analyzed by material characterizations. Moreover, the service life of annealed ceramics is predicted through theoretical calculation. The crystallization of inter-granular glassy phase results in the decreased fracture strength of the alumina ceramic, but increases its long-time service reliability. The existence of inter-granular crystalline phases is responsible for the increase of flaw tolerance and corrosion-resistance of the alumina ceramic, and therefore the alleviated static fatigue can be obtained after annealing. Furthermore, the reliability of the annealed ceramic-Kovar alloy composite joints is analyzed, in which the stresses induced by brazing may lead to cracks in the alumina ceramic. In summary, this work discusses the influence of the crystallization of inter-granular glassy phase on the mechanical performance of alumina ceramics, which is of great value for developing ceramics with excellent mechanical reliability. [ABSTRACT FROM AUTHOR]

Two new selenites, K2Zn3Se4O12 (compound 1) and K4Zn3V4Se2O19 (compound 2), have been successfully synthesized by solid-state reactions in vacuum tubes. Compound 1 consists of a three-dimensional (3D) framework with [SeO3] triangular pyramids and [ZnO4] tetrahedra in the monoclinic space group P21/c (No. 14). Compound 1′s cut-off edge is below 344 nm, based on its UV-Vis-NIR diffuse reflectance studies, and theoretical calculations indicate a birefringence of around 0.043 at 1064 nm. The two-dimensional layer of compound 2, in contrast, is made up of [SeO3] triangular pyramids, [ZnO4] tetrahedra, and [V4O13] tetrahedra. It crystallizes in the monoclinic space group C2/c (No. 15). Its UV-Vis-NIR diffuse reflectance studies demonstrate that the compound's cut-off edge is lower than 330 nm. [ABSTRACT FROM AUTHOR]

Two new selenites, K2Zn3Se4O12 (compound 1) and K4Zn3V4Se2O19 (compound 2), have been successfully synthesized by solid-state reactions in vacuum tubes. Compound 1 consists of a three-dimensional (3D) framework with [SeO3] triangular pyramids and [ZnO4] tetrahedra in the monoclinic space group P21/c (No. 14). Compound 1′s cut-off edge is below 344 nm, based on its UV-Vis-NIR diffuse reflectance studies, and theoretical calculations indicate a birefringence of around 0.043 at 1064 nm. The two-dimensional layer of compound 2, in contrast, is made up of [SeO3] triangular pyramids, [ZnO4] tetrahedra, and [V4O13] tetrahedra. It crystallizes in the monoclinic space group C2/c (No. 15). Its UV-Vis-NIR diffuse reflectance studies demonstrate that the compound's cut-off edge is lower than 330 nm. [ABSTRACT FROM AUTHOR]

In order to break through the speed bottleneck, researchers envision using tubes to cover high-speed maglev trains and extract some of the air inside the tubes, creating a low-density environment on the ground, greatly reducing the aerodynamic drag of the trains, and in a relatively economical and feasible way, making high subsonic (600 km/h and above) and even supersonic ground transportation possible. The faster the running speed of high-speed trains, the greater the impact of aerodynamic drag on their energy consumption. Studying the aerodynamic characteristics of trains with a speed of 600 km/h can help optimize the aerodynamic shape of the train, reduce aerodynamic drag, and reduce energy consumption. This has positive implications for improving train energy efficiency, reducing energy consumption, and environmental impact. This paper adopts the numerical simulation method to study the drag reduction effect of the plasma arrangement and different excitation speeds on the train set in four positions when the incoming wind speed is 600 km/h, to analyze the mechanism of drag reduction, and then to analyze the combination of working conditions in order to investigate the drag reduction effect of plasma on the vacuum tube train set with an ambient pressure of 10,000 Pa. The findings demonstrate that the plasma induces the directional flow of the gas close to the wall to move the flow separation point backward and delay the separation of the flow, thereby reducing the front and rear differential pressure drag of the train set and lowering the aerodynamic drag coefficient of the entire train. The plasma arrangement is located at the rear of the flow separation point and in close proximity to the flow separation point. The pneumatic drag reduction effect peaks when the excitation speed reaches 0.2 times the train speed and the pneumatic drag reduction ratio is around 0.88%; the pneumatic drag reduction ratio of the rear car peaks when the excitation speed reaches 0.25 times the train speed and the pneumatic drag reduction ratio is 1.62%. The SDBD (Surface Dielectric Barrier Discharge) device is installed at the flow separation point around the nose tip of the rear car. [ABSTRACT FROM AUTHOR]

In this paper, we express Thévenin equivalent circuits seen looking into the terminals of the small-signal model of the vacuum tube triode in terms of the Thévenin equivalent circuits seen looking out of the other terminals and apply them to the analysis of the common-cathode, common-plate, and common-grid single-tube amplifier configurations, as well as a differential pair amplifier. This is an adaptation of equivalent circuit techniques for transistor circuits pioneered by Marshall Leach. The use of equivalent circuits can yield intuitive solutions that avoid solving sets of equations. [ABSTRACT FROM AUTHOR]

The article presents the results of the study on the amplitude-time characteristics of pulsed discharges and ion flux formation processes in spark-arc ion sources used in small vacuum neutron tubes. The obtained data show that the initial phase of the discharge ignition is accompanied by the development of instabilities that affect the formation of ion fluxes. An interruption of the vacuum arc at the moment of a change in the discharge current polarity results in a sharp change in the energy characteristics of the discharge and the neutron yield of the tube. Based on the results of the study, options are proposed for constructing pulsed power supply systems based on ion sources that increase the operational stability of neutron generators. [ABSTRACT FROM AUTHOR]

Vacuum dewatering methods are widely used to treat high-moisture dredged sludge; however, significant particle migration problems exist during treatment, particularly for sand–clay mixture slurries. A dewatering technology called a vacuum tube filter (VTF) system is proposed herein to alleviate the particle migration problem of sand–clay mixture slurries. First, four sets of model tests were performed using the VTF system and conventional vacuum (dewatering) method (CVM, i.e., a prefabricated strip-shaped drain assisted by vacuum) with two types of sand–clay mixed slurries. The water content distribution, settlement, and discharged water from the VTF system were compared with those from the CVM. The VTF system was superior to the CVM in terms of the dewatering rate and effect. Moreover, the particle migration problem was theoretically analyzed using a consolidation solution. With both slurries, the VTF system exhibited a lower particle-migration-problem-induced clogging effect. Thus, the VTF system can effectively alleviate the particle migration problem and enhance the dewatering of high-moisture sand–clay slurries. [ABSTRACT FROM AUTHOR]

Well-standardized procedures in the pre-analytical phase of urine diagnostics is of utmost importance to obtain reliable results. We investigated the effect of different urine collection methods and the associated urine transfer tubes on urine test strip and particle results. In total, 146 selected urine samples were subdivided into three different collection containers and subsequently transferred into its accompanying transfer tube (BD, Greiner, Sarstedt vacuum and Sarstedt aspiration). As reference, the original urine sample was directly measured on the analyser. Both chemical test strip analysis (Sysmex UC-3500) and fluorescence flow cytometry particle analysis (Sysmex UF-5000) were performed on all samples. No statistically significant differences in test strip results were found between the studied transfer methods. On the contrary, transfer of urine samples to the secondary tubes affected their particle counts. Clinically significant reductions in counts of renal tubular epithelial cells and hyaline casts were observed using the BD and Greiner transfer tubes and in counts of pathological casts using the BD, Greiner and Sarstedt vacuum tubes. The results of this study indicate that the use of urine transfer tubes may impact counts of fragile urine particles. Clinical laboratories need to be aware about the variation that urine collection methods can induce on urine particle counts. [ABSTRACT FROM AUTHOR]

The study intends to analyze the thermal performance of a novel solar air heater based on heat pipe vacuum tube solar collector and finned-tube heat exchanger. The solar collector has been introduced with a new header where heat transfer fluid (Therminol-55) gains heat directly in contact with the condenser section of the heat pipe. This eliminates thermal paste application between the condenser and manifold in the existing systems. The system's thermal performance has been experimentally evaluated using two different (four-row and eight-row) finned-tube heat exchangers at four varied air flow rates, viz. 100 kg h–1, 400 kg h–1, 700 kg h–1 and 1000 kg h–1. The system with eight-row heat exchanger performed better than the four-row heat exchanger at each air flow rate. 100 kg h–1 resulted in a maximum rise in temperature of air (55.4 °C) and maximum outlet temperature of air (89.4 °C). Meanwhile, the maximum energy and exergy efficiency of 95.7% and 2.17% were observed at 1000 kg h–1. The maximum effectiveness of the four and eight-row heat exchangers was found as 70.7% and 79.4%, respectively, at 100 kg h–1. The monthly cost saving by utilization of the proposed system is 65.65 $, and the payback period is 12.4 months. The amount of CO2 averted from releasing into the atmosphere is 787.7 kg per month. The results suggest the utility of the proposed solar air heater as an environment-friendly replacement for conventional air heaters for consistent operation in the daytime. The experimental study was performed at the campus of NIT Kurukshetra, India (29.9476°N, 76.8155°E). [ABSTRACT FROM AUTHOR]

Background: As previously reported, the measurement of ethanol can also be affected by interference from hemolysis. This is a matter of concern since ethanol is widely regarded as the most commonly abused substance globally. When sample re-collection is ordered to eliminate hemolysis effects for ethanol testing, this can have unfavourable consequences for these patients. Rapid detection of hemolysed specimens would alleviate some issues associated with forensic samples. This study aimed to assess the qualitative analytical performance of a novel point-of-care testing device per the guidelines specified in CLSI-EP-12A document. HemCheck™ is a novel POCT device that qualitatively detects free-hemoglobin levels on the specimen shortly after drawing the sample. Methods: The system consists of two components. One is a cartridge with a needle that is used to transfer a small volume of whole blood from a vacuum tube to vertical and lateral flow filtration. The second component is the reader. The consumable cartridges are designed to be inserted into the reader without requiring the syringe or blood collection tube removal. A red indicator led illuminates, indicating that the sample has been hemolysed. To assess the imprecision of the method, we determined the C5-C95 interval and C50, using the Roche Cobas clinical chemistry analyser as the comparator. For this study, we utilised residual samples. Results: Our C50 concentrations were 45 mg/dL, the C5- C95 30 mg/dL and 60 mg/dL, respectively. Two methods reveal an overall agreement of 89.2%. The diagnostic sensitivity and specificity of the study showed a positive agreement of 95.7% and a negative agreement of 80. C%. The calculated Cohen's Kappa value was 77.3%. Conclusionn: According to current literature, a bias in ethanol levels can be noticed even with small free hemoglobin concentrations. When it came to forensic samples, this bias was crucial. Our study confirmed that the HemCheck devce has acceptable analytical performance, as outlined in the CLSI-EP-12A document. Although the possible beneficial impacts of the innovative POCT hemolysis detection device on the preanalytical phase are proposed, we have not studied them in this study. Uvod: Kao što je ranije objavljeno, na merenje etanola može uticati i interferencija hemolize. Ovo je zabrinjavajuće jer se etanol smatra supstancom koja se najčešće zloupotrebljava u svetu. Kada se naloži ponovno uzimanje uzorka da bi se eliminisali efekti hemolize na testiranje etanola, to može imati nepovoljne posledice za pacijente. Brzo otkrivanje hemolizovanih uzoraka bi dalo odgovore na neke probleme povezane sa forenzičkim uzorcima. Ova studija je imala za cilj da proceni kvalitativne analitičke performanse novog uređaja za testiranje na licu mesta, u skladu sa smernicama navedenim u dokumentu CLSI-EP- 12A. HemCheck'" je novi POCT uređaj koji kvalitativno detektuje nivoe slobodnog hemoglobina na uzorku ubrzo nakon uzorkovanja. Metode: Sistem se sastoji od dve komponente. Jedan je kertridž sa iglom koji se koristi za prenošenje male zapre- mine pune krvi iz vakuumske cevi do filtracije vertikalnog i bočnog protoka. Druga komponenta je čitač. Potrošni ker- tridži su dizajnirani da se umetnu u čitač bez potrebe za uklanjanjem šprica ili epruvete za prikupljanje krvi. Crvena indikatorska lampica svetli, što ukazuje da je uzorak hemo- lizovan. Da bismo proceniii nepreciznost metode, odredili smo interval C5-C95 i C50, koristeći klinički Roche Cobas analizator kao komparator. U ovoj studiji smo koristili rezidualne uzorke. Rezultati: Naše koncentracije C50 su bile 45 mg/dL, C5- C95 30 mg/dL i 60 mg/dL, respektivno. Dve metode otkrivaju ukupno slaganje od 89,2%. Dijagnostička osetljivost i specifičnost studije pokazala je pozitivno slaganje od95,7% i negativno slaganje cd 80,0%. Izračunata Koenova Kapa vrednost je bila 77,3%. ZeWjL>5aL FYema trenutnoj literaturi, pristrasrost nivoa etanola se može primetiti čak i sa malim koncentracijama slobodnog hemoglobina. Kada su u pitanju forenzički uzorci, ova pri st rasno st je bila ključna. Naša studija je potvrdila da HemCheck uređaj ima prihvatljive analitičke performanse, kao što je navedeno u dokumentu CLSI-EP-12A. lako su predloženi mogući korisni uticaji inovativnog POCT uređaja za detekciju hemolize na preanalitičku fazu, mi ih nismo proučavali u ovoj studiji. [ABSTRACT FROM AUTHOR]

Laser-induced surface structuring is a promising method to suppress electron mulitpacting in the vacuum pipes of particle accelerators. Electrons are scattered inside the rough surface structure, resulting in a low Secondary Electron Yield (SEY) of the material. However, laser processing of internal pipe surfaces with a large aspect ratio is technologically challenging in terms of laser beam guidance and focusing. We present a 532 nm ultrashort-pulse laser setup to process the inner parts of 15 m long beam vacuum tubes of the Large Hadron Collider (LHC). Picosecond pulses at a repetition rate of 200 kHz are guided through an optical fiber toward an inchworm robot traveling inside the beam pipe. The system was installed, characterized, and tested for reliability. First surface treatments achieved the required scan precision. Cu2O-dominated nano-features were observed when processing at high average laser power (5 W) and slow scanning speed (5 mm s−1) in nitrogen flow, and the maximum SEY of copper was decreased from 2.1 to 0.7. [ABSTRACT FROM AUTHOR]

An innovative indirect solar dryer, designed for banana dehydration, was developed and assessed, utilizing the Ansys software for simulation. The system comprises a vacuum tube water heater and a drying chamber, the latter of which incorporates phase-change materials (PCMs), thus enhancing the drying performance. A fan positioned within the chamber synergizes with the PCMs, effectively abbreviating the drying time. Computational simulations were executed to refine the system design and operational parameters. A sorption isotherm was constructed to delineate the optimal moisture content and water activity, fundamental parameters for efficient drying. The integrated solar collector facilitates the transformation of solar energy into heat, while the drying chamber, accommodating two baskets of produce, optimizes the heat distribution. Our system demonstrated the capacity to generate high drying temperatures, especially efficient for items exhibiting lower moisture content than bananas. The system achieved a predicted maximum efficiency of 67.40%, operating optimally within a temperature range of 60-65°C. Experimental results were congruent with computational simulations, reinforcing the efficacy of the drying chamber. This study introduces a novel, sustainable method for efficient fruit dehydration, spotlighting its potential applicability beyond bananas to other produce. [ABSTRACT FROM AUTHOR]

By going through a history of electronic visuality, from fluorescence glows in European laboratories in the nineteenth century to the computer screen in the twentieth century, this paper discusses technical image operations in the interaction between media machines and media people. Examining this set of apparatus from the evolution of a neglected technical object – the vacuum tube, it traces the history of the screen and the temporal-spatial composition of electronic graphics in television, radar, and early computer systems. In doing so, it outlines the entangled history of analog and digital displays and demonstrates the impossibility of neglecting the role of the human observer in the technical invention of visuality. [ABSTRACT FROM AUTHOR]

In this paper, an eco-design criterion for a novel solar desaltification setup (SDS) with evacuated annular tube collector (EATC) and a specific set of modified combination of parabolic concentrator has been examined for maximum performance with environmental and economic circumstances. This technique approaches to rectify the irregular utilization of EATC for optimum performance with environ-economic viabilities, which evidently satisfies the eco-design requirements and boosts the solar absorption capabilities uniformly along the periphery of vacuum tubes, and results improved thermo-syphon loom significantly more than in typical applications. The suggested unit is being refined and improved water temperature by 11.4% while keeping the basin lid and annular tubes at the same direction (30°). An incremental improvement in thermo-syphon circulation of 28.1% obtained through the present study. The average solar intensity of the respective clear day has been found as 401.8 kW and the overall energy and exergy efficiency on a daily basis are 50.8%, and 3.8%, correspondingly. At a minimal retail price of 0.07 $/l, and improved daily output by 12.3 kg per day than the typical SDS-EATC system taken for comparison into consideration are determined to be more satisfactory. 131.97 and 67.44 tons alleviates for $1318.36 and $673.77 from environmental generated money based on energy-exergy are there for CO2, respectfully. The setup cost is noticeably reduced by 9.15% to the comparative system, and its productivity is determined to be 940.8% (> 100%), and this indicates that the present system is highly viable and appreciable for the feasible adaptation with the positive environ-economic possibilities. [ABSTRACT FROM AUTHOR]