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The importance of the energy transition and the role of green hydrogen in facilitating this transition cannot be denied. Therefore, it is crucial to pay close attention to and thoroughly understand hydrogen storage, which is a critical aspect of the hydrogen supply chain. In this comprehensive review paper, we have undertaken the task of categorising and evaluating various hydrogen storage technologies across three different scales. These scales include small-scale and laboratory-based methods such as metal-based hydrides, physical adsorbents, and liquid organic hydrogen carriers. Also, we explore medium and large-scale approaches like compressed gaseous hydrogen, liquid cryogenic hydrogen, and cryocompressed hydrogen. Lastly, we delve into very large-scale options such as salt caverns, aquifers, depleted gas/oil reservoirs, abandoned mines, and hard rock caverns. We have thoroughly examined each storage technology from technical and maturity perspectives, as well as considering its techno-economic viability. It is worth noting that development has been ongoing for each storage mechanism; however, numerous technical and economic challenges persist in most areas. Particularly, the cost per kilogramme of hydrogen for most current technologies demands careful consideration. It is recommended that small-scale hydrogen storage technologies such as metal hydrides (e.g., MgH 2 , LiBH 4) need ongoing research to enhance their performance. Physical adsorbents have limited capacity except for activated carbon. Some liquid organic hydrogen carriers (LCOHs) are suitable for medium-scale storage in the near term. Ammonia-borane (AB), with its high gravimetric and volumetric properties, is a promising choice for medium-scale storage, pending effective dehydrogenation. It shows potential as a hydrogen carrier due to its high storage capacity, stability, and solubility, surpassing DOE targets for storage capabilities. Medium-scale storage, utilising compressed gas cylinders and advancements in liquefied and cryocompressed hydrogen storage, requires cost reduction measures, and a strategic supply chain. Large-scale storage options include salt caverns, aquifers, and depleted gas/oil reservoirs, with salt caverns offering pure hydrogen, need further techno-economic analysis and deployment projects to mature, but storage costs are reasonable, ranging mostly from €0.25/kg to €1.5/kg for location specific large-scale options. • Comprehensive review of hydrogen storage technologies from small to very large scale. • Metal hydride MgH 2 shown to be economically viable with storage at €2.8 per kg. • Ammonia-borane (AB) offers promising medium-scale hydrogen storage potential. • Technological advancements are enhancing compressed gas hydrogen storage systems. • Large-scale hydrogen storage costs vary between €0.25 and €1.58 per kg. [ABSTRACT FROM AUTHOR]

After production and before the use in different applications, hydrogen may need to be purified, transported, compressed and stored. Hydrogen is conventionally stored in high pressure gas cylinders and, as a liquid phase at low temperatures, in opened tanks. These methods present several economic and security problems. So, hydrogen storage in liquid or solid carriers is a suitable method for future applications. Hydrogen absorption and desorption in metal and complex hydrides will be discussed. Examples are provided, including the role of additives in promoting hydrogen sorption reactions. Some case studies using metal hydrides as hydrogen carrier are presented. The HyCARE project, focussed on the development of an efficient metal hydride-based system for the storage of renewables energies is presented, giving evidence of about 50 kg of hydrogen stored in metal hydrides. A small-scale hydrogen refuelling station developed to provide hydrogen for a fuel cell driven drone will be described. The Life Cycle Assessment (LCA) methodology to evaluate the environmental impacts associated with developed systems is also shortly described. Finally, main open challenges will be outlined, suggesting possible approaches for their overcoming. [ABSTRACT FROM AUTHOR]

The hydrogen tube skid container is designed to protect the hydrogen gas cylinder group from insolation, rain, and other environmental factors. However, in the event of a leakage accident, the container becomes a confined space. Therefore, it is essential to assess the risks associated with high-pressure hydrogen leakage in this confined space and determine the effectiveness of various risk mitigation methods under conditions of natural ventilation and forced ventilation, taking into consideration factors such as inlet velocity and vent position. The results showed forced ventilation was more effective than natural ventilation in reducing potential risks associated with hydrogen leakage. Furthermore, the magnitude of inlet velocity and the positioning of the vent were found to play crucial roles in reducing hydrogen concentration within the confined space. The vents on the horizontally symmetrical top (R–UP cases) were the most effective for ventilation. With the inlet air velocity set to 15 m/s, forced ventilation could reduce the average hydrogen molar fraction to the theoretical lower flammability limit (LFL) in approximately 17 s. [Display omitted] • The inlet air velocity and vent positions affect the discharge capability of leaked hydrogen. • Multi-perspective analysis of the distribution of leaked hydrogen at different time periods. • Placing vents on both sides at the top proves to be the most effective ventilation method. [ABSTRACT FROM AUTHOR]

The use of Type IV cylinders for gas storage is becoming more widespread in various sectors, especially in transportation, owing to the lightweight nature of this type of cylinder, which is composed of a polymeric liner that exerts a barrier effect and an outer composite material shell that primarily imparts mechanical strength. In this work, the failure analysis of an HDPE liner in a Type IV cylinder for high-pressure storage was carried out. The breakdown occurred during a cyclic pressure test at room temperature and manifested in the hemispherical head area, as cracks perpendicular to the liner pinch-off line. The failed sample was thoroughly investigated and its characteristics were compared with those of other liners at different stages of production of a Type IV cylinder (blow molding, curing of the composite material). An examination of the liner showed that no significant chemical and morphological changes occurred during the production cycle of a Type IV cylinder that could justify the liner rupture, and that the most likely cause of failure was a design-related fatigue phenomenon. [ABSTRACT FROM AUTHOR]

Due to its better energy storage density and lower costs for storage, cryo-compressed hydrogen (CcH2) storage provides a wide range of research potential. Based on the grid theory, The type III CcH2 storage cylinder's layup scheme is created using the working environment for on-board hydrogen storage. The failure of the composite layer of gas cylinders was determined using the maximum stress criterion, and hydrodynamic bursting tests on small-volume gas cylinders were utilized to confirm that the design method was appropriate. The innermost layer of the ring winding is where the largest fiber stress is found, according to simulation studies. The load-bearing capacity of the cylinder is improved and can reach 115.1 MPa with layers in the order of [ 90 / ± 11.8 / 90 ]. The equivalent stress and fiber stress ratio of the cylinder continuously drop as the autofrettage pressure rises, while the cylinder's fatigue life gradually lengthens. • A program for designing hydrogen storage cylinders under cryo-compressed situation. • Stress analysis of each component of the cryogenic hydrogen storage cylinder. B • Urst failure of hydrogen storage cylinders and experimental validation. • Layup order's impact on the durability of cryogenic hydrogen storage cylinders. • Autofrettage pressure's impact on hydrogen storage cylinder fatigue performance. [ABSTRACT FROM AUTHOR]

Based on the classical grid theory and related regulations, a structure model of a fiber-wound composite gas cylinder was designed in this paper. Based on the design results, a finite element model of a fully wound composite cylinder of an aluminum alloy inner liner with a working pressure of 35 MPa was established based on the ABAQUS software, and its stress distribution under working pressure and minimum burst pressure was analyzed. According to engineering experience, the pressure tolerance of composite cylinders can be improved by proper autofrettage pressure before working pressure, so the influence of autofrettage pressure was analyzed in this paper. The optimum autofrettage pressure was selected by setting the autofrettage gradient, and damage analysis was carried out on the cylinder with nominal working pressure of 35 MPa based on the Hashin failure criterion. The results show the initial damage sequence: matrix stretching occurs before the fiber stretching, and the damage generally starts from the spiral-wound layer. The tensile damage first appears in the transition section between the head and the barrel body, and the damage of the spiral-wound layer develops from the inner layer of the wound layer to the outer layer, while the damage of the circumferentially wound layer develops from the outer layer to the inner layer. [ABSTRACT FROM AUTHOR]

The evolution of a double-layer gas cylinder under various Mach numbers (M = 1.27, 1.5, 1.7, and 2.1) and Atwood numbers (A = 0.504, 0.392, 0.194, and −0.202 for the first layer) are studied numerically. At M ≥ 1.5 and A = 0.504, a bulge is generated near the upstream pole of the outer cylinder due to the impingement of a reflected shock wave, which promotes the formation of an upstream jet. At a higher Mach number, the evolution of the jet is suppressed under the influence of a higher pressure upstream of the jet head. The compressibility effects are quantified by the widths and heights of the gas cylinders. The Atwood number is associated with nonlinear acoustic effects, and the sign of A results in a significant variation in the wave patterns. The development of vortex pairs slows down with the decreasing Atwood numbers in the scenario of A > 0 for the first layer gas cylinder, while vortex pairs emerge and propagate in both upstream and downstream directions from the outer interface in the scenario of A < 0 for the first layer. As the Mach numbers and the magnitude of the Atwood numbers are increased, the mixing of various gases is promoted by detecting the circulation and mixed mass. The net circulation can be predicted by the linear summation of the Picone and Boris model and the Samtaney and Zabusky model under various Mach and Atwood numbers. [ABSTRACT FROM AUTHOR]

An effective numerical analysis process was carried out to simulate an impact event based on the Hashin failure criterion and the Camanho degradation rule. The middle and shoulder of a cylinder were impacted by the edge of square-shaped impactors, and the remaining burst pressure was predicted. The accuracy of the numerical analysis was verified by results of two experiments that proved that the numerical analysis was reliable. The impact damage at different impact energies (20-200 J) was evaluated. According to the analysis carried out, the impact damage of gas cylinders intensified with increasing impact energy, and there existed a critical value of this energy. The damaged area of gas cylinders under the same impact energy first decreases and then increases from the inner to outer layer, and the maximum increase in the residual bursting pressure could reach 9.6%. [ABSTRACT FROM AUTHOR]

There is a considerable difference in wall thickness between the mouth and the cavity of thin-walled and thick-mouthed seamless gas cylinders, and the existing manufacturing processes are unable to effectively meet product requirements. To overcome such issue, a step-by-step boring-necking-spinning solution for gas cylinders was proposed, in which sufficient wall thickness is reserved for the mouth area of the cylinder blank, followed by necking-spinning to realize the overall forming of thin-walled, thick-mouthed seamless gas cylinders. The stress–strain distribution and geometric dimensional changes of gas cylinders during the spinning process were investigated by means of finite element simulation, and the effects of different process parameters on the stress and wall thickness of the bottle mouth were analyzed. Further, multi-objective optimization of the response surface model was performed using the NSGA-II algorithm to derive a set of optimal process parameters. Finally, the correctness of the simulation and optimization results was verified experimentally, and the expected geometry and optimal strain state of the gas cylinder were obtained. The newly developed processing solution represents a groundbreaking advancement in the manufacturing of thin-walled and thick-mouthed gas cylinders. [ABSTRACT FROM AUTHOR]

There is a considerable difference in wall thickness between the mouth and the cavity of thin-walled and thick-mouthed seamless gas cylinders, and the existing manufacturing processes are unable to effectively meet product requirements. To overcome such issue, a step-by-step boring-necking-spinning solution for gas cylinders was proposed, in which sufficient wall thickness is reserved for the mouth area of the cylinder blank, followed by necking-spinning to realize the overall forming of thin-walled, thick-mouthed seamless gas cylinders. The stress–strain distribution and geometric dimensional changes of gas cylinders during the spinning process were investigated by means of finite element simulation, and the effects of different process parameters on the stress and wall thickness of the bottle mouth were analyzed. Further, multi-objective optimization of the response surface model was performed using the NSGA-II algorithm to derive a set of optimal process parameters. Finally, the correctness of the simulation and optimization results was verified experimentally, and the expected geometry and optimal strain state of the gas cylinder were obtained. The newly developed processing solution represents a groundbreaking advancement in the manufacturing of thin-walled and thick-mouthed gas cylinders. [ABSTRACT FROM AUTHOR]

In conditions of constant growth in the cost of traditional oil products and their shortage, the issue of using alternative fuels becomes urgent. The purpose of the article is to identify ways of using alternative types of fuel for the operation of diesel engines. Research methods - analysis and verification of data obtained from scientific publications, which are part of the world-famous scient metric databases, for the relevance of the subject of research. The research results reveal the advantages and disadvantages of dual-fuel engines operating on gaseous fuel with diesel fuel additive, the impact of this type of engine on emissions and toxicity of exhaust gases, in particular nitrogen oxides NOx. The application of the so-called gas nozzle and the cross-section of the holes of its nozzles are substantiated. It was analysed and established that the most economically expedient is the use of liquefied petroleum gas for the operation of diesel engines by implementing the gas-liquid cycle; it was found that the most promising for this is gas cylinder equipment of the so-called 4th generation. A retrospective analysis of studies of internal combustion engines with gas cylinder equipment showed an increase in motor resource when using gaseous fuels, as well as the negative side of using gaseous fuels, which consists in reduced power when converting carburettor engines, however, the use of these fuels for the operation of diesel engines completely eliminates this disadvantage. Based on the research analysis, the influence of the ignition dose, when the engine is operating on the gas-diesel cycle, on the performance at different loads was also established, and a recommendation was found to switch to the diesel cycle from the gas-diesel cycle at loads less than 30% of the nominal one. The optimal scheme for the implementation of the gas-diesel cycle, which is relevant and promising for more widespread energy and transport vehicles, has been substantiated and selected. Based on the analysed schemes, it was established that the scheme that can be taken as a basis for further research in this direction is the scheme of the DG-Flex BOSCH gas-diesel system. The practical value of the work lies in the justification of complex conversion with partial replacement of diesel fuel with liquefied petroleum gas as the most rational way of converting serial diesel engines into dual-fuel engines. [ABSTRACT FROM AUTHOR]

Laser shadowgrams of exploding metal wires in a vacuum show the anomalous transparency of a completely evaporated wire core for a probe beam with a wavelength of 1064 nm. Simultaneous shadowgrams at 532 nm show significant light attenuation. The anomalous transparency for laser radiation at a wavelength of 1064 nm is highly likely due to the Rayleigh scattering of the probing beam by metal atoms. Our experimental results can be explained under the assumption of a strongly non-equilibrium state of an expanding gas cylinder with a non-uniform density. [ABSTRACT FROM AUTHOR]

Engine researchers focused on alcohol fuels since the invention of diesel engines in the 1900s, and the rise in petrochemical costs in the 1970s triggered this concern. This study investigates the impacts of the injection start timing, pilot injection application, and boost air pressure increase, on combustion and exhaust emissions in a common rail diesel engine fueled with ethanol/butan-2-ol/diesel blends. The lowest combustion noise was obtained in the pilot injection application as 83.8 dB in E15B3. The results indicated that the peak point of cylinder gas pressure rose by more than 5 % in the application of pilot fuel injection and advanced injection timing, compared to conventional engine operating conditions. However, maximum CO 2 and NO x were seen in the pilot injection application using FBDF as 5.7 % and 670 ppm, respectively. As alcohol rate increases in fuel blends, the average 1.3 °CA in the ignition delay period was increased, while the total combustion period was shortened more than 6 °CA. This result shows that the combustion reactions of alcohol/diesel fuels occur faster than pure diesel. However, the variation in the ignition delay and total combustion periods of the test fuels considerably reduced with pilot fuel injection application. These results indicates that pilot fuel injection may be applied very controlled according to changing engine conditions. It was calculated in statistical analysis that except for the coefficient variation of the maximum pressure increase rate, the other coefficient variation values were relatively stable and below 3 %. In addition, it was determined that the results of the finite element analysis are proportional to the pressure values obtained experimentally. [Display omitted] [ABSTRACT FROM AUTHOR]

Simple Summary: Mealybugs (Hemiptera: Pseucoccidae) are frequently detected pests when importing fresh commodities. Ethyl formate, a methyl bromide alternative fumigant, has been applied to imported bananas in Korea to eliminate mealybugs, but it represents a considerable cost for production and management. A liquid ethyl formate treatment technology was newly developed to reduce the cost, and the efficacy of this technology against Planococcus citri, a highly important species of mealybug in Korea, was evaluated in this study. In addition, the effect of enhancing the control against P. citri was evaluated through the simultaneous treatment of ethyl formate and phosphine. The results show that, for the treatment with ethyl formate + nitrogen, the control effect did not decrease with the addition, and fruit damage did not occur as the nitrogen concentration increased. In the case of the combined treatment with phosphine, the control effect was greatly increased even when a small amount (0.1 g/m3) was applied. The results indicate that the new technology can be used to control mealybugs on banana fruits, and a combined treatment of ethyl formate and phosphine can also enhance the efficacy against mealybugs. Currently, the fumigant ethyl formate (EF) is stored as a liquified gas in metal cylinders mixed with carbon dioxide (CO2), but this product type is expensive to manufacture, transport, and maintain in cylinders. To address these problems, we developed a new EF fumigation technique with a nitrogen (N2) carrier. In this report, the susceptibility of citrus mealybugs, one of the most resistant mealybugs to fumigants, to EF was assessed; the phytotoxicity of an EF + N2 concurrent treatment applied to banana fruit was examined to evaluate the efficacy compared to the current EF + CO2 product; and the increased efficacy with a phosphine (PH3) addition to EF + N2 was also assessed. Concurrent treatment of EF and N2 was performed at an LC50 concentration of EF. N2 was applied in seven doses from concentrations of 79% to 95%. The phytotoxicity of EF to bananas was assessed by applying EF at 35 mg/L with N2 at 79%, and the color, sugar content, and weight loss of bananas were measured for 14 days after treatment. The EF with N2 treatment resulted in more than 50% mortality at all growth stages of the mealybug, and there was no significant difference between the untreated and treated banana fruits. EF mixed with PH3 showed a higher efficacy than treatment with EF alone, but only a slight increase in efficacy was observed when the PH3 concentration increased. These results indicate that concurrent treatment with EF and N2 can be used to control mealybugs on banana fruits, and combined treatment with EF and PH3 can also enhance the efficacy against mealybugs. [ABSTRACT FROM AUTHOR]

Natural gas hydrate (GH) is a significant potential energy source due to its large reserves, wide distribution, high energy density and low pollution. However, the gas production rate of past gas hydrate production tests is much lower than the requirement of commercial gas production. Reservoir stimulation technologies like hydraulic fracture provide one potential approach to enhance gas production from GH. The reservoir reformation behaviour of the hydrate-bearing sediments (HBS), particularly sediments with a high clay content, is a complex process during a hydraulic fracturing operation, which has been poorly understood and thus hardly predictable. This paper presents an experimental facility that was developed to analyze the hydraulic fracture mechanism in synthesized HBS. This facility can be used to form GH in sediments, conduct visual observation of hydraulic fracturing experiments, and measure the permeability of HBS under high pressure (up to 30 MPa) and low-temperature conditions (from 253.15 K to 323.15K). It is mainly composed of a pressure control and injection unit, a low temperature and cooling unit, a cavitation unit, a visual sapphire reactor, and a data acquisition and measurement unit. The hydraulic fracture module is consisting of a gas cylinder, fracturing pump, hopper, proppants warehouse and valves. The sapphire reservoir chamber is applied to observe and measure the fracture of HBS during hydraulic fracturing. The permeability test module is composed of a constant-flux pump and pressure sensors, which can evaluate the permeability performance before and after hydraulic fracture in HBS. The fundamental principles of this apparatus are discussed. Some tests were performed to verify hydraulic fracture tests and permeability tests could be practically applied in the HBS exploitation. [ABSTRACT FROM AUTHOR]

The high-pressure gas cylinder is the pressure source for liquid propellant engine valve control. Leakage is a significant cause of pressure loss in gas cylinders, leading to engine control failure and serious flight accidents. In this paper, a model-based approach to estimate the leakage area and remaining useful life (RUL) of gas cylinders is proposed. To estimate the leakage area, a state space representation of the cylinder system is developed based on the nonlinear model derived from momentum, energy, and continuity equations. Leakage is defined as a system state, and an extended Kalman filter (EKF) as a state observer is implemented to estimate the leakage area. Internal pressure measurements of the gas cylinder are required as output parameters in the estimation process. Then, the estimated states are fed into the nonlinear model to iteratively calculate the RUL of the cylinder. To evaluate the effectiveness of the proposed method, scaling leakage test data, computational fluid dynamics (CFD) simulation results, and liquid rocket engine (LREs) hot test data are used. Calibration results have proved the validity and universality of the method, with the mean absolute error (MAE) for the remaining 80% useful life prediction results being less than 0.02, 0.04, and 1.10. This study can provide technical support for fault tolerance control and orbital replanning in case of control gas cylinder leaks. [ABSTRACT FROM AUTHOR]

The ongoing COVID‐19 pandemic has been a daunting challenge for healthcare systems worldwide. The World Health Organization has recommended various measures to reduce or limit the spread of the virus, one of which includes the use of face masks. This increase in their demand has provided a unique opportunity to improve the technology by offering, in addition to their inherent protection, therapeutic benefits. One such benefit involves inhaled nitric oxide (iNO) therapy. iNO has proven to be a beneficial therapeutic in patients with acute, hypoxemic respiratory failure and lung injury. Specifically, its potential application stems from its ability to rapidly increase oxygen partial pressure in arterial blood. However, iNO treatments generally require pressurized gas cylinders which are coupled with high costs and lack of portability. A face mask which can deliver therapeutic NO is developed using humidity‐triggered NO‐releasing nanoparticles. This platform can deliver a low dose of 2.1–2.5 ppm NO for 90 min in a sustained manner. Moreover, it can be stored for extended periods of time and can be easily transported due to its light weight. This NO mask has the potential to alleviate the strain that affects financially limited healthcare systems in developing regions. [ABSTRACT FROM AUTHOR]

Production methods for practical sources are reported for 161Dy, 166Er, and 169Tm Mössbauer spectroscopy. Dy0.5Gd0.5F3 can be a useful source material by neutron irradiation for 161Dy Mössbauer spectroscopy. The fluoride was synthesized from rare-earth oxides by the "wet" method. HoAl2 is a useful source material above 40 K for 166Er Mössbauer spectroscopy by neutron irradiation. Ho0.4Y0.6H2 is an alternative source material usable for lower temperatures, although Ho0.4Y0.6H2 is not appropriate for repetitive use. A safer method for hydrogenation using TiH2 instead of a H2 gas cylinder will help the source production. Er-Al alloy including about 10-wt% of Er can be used as 169Tm Mössbauer source by neutron irradiation. Alternative source production method by high-energy X-rays using electron linear accelerator is discussed for 161Dy Mössbauer source. These production methods will be used complementarily for many other sources and absorbers. This report reconsiders the existing approaches and a revision of practical methods for the preparation of the sources for 161Dy-, 166Er- and 169Tm-Mössbauer spectroscopy [ABSTRACT FROM AUTHOR]

The features and performance of a hydrogen energy storage system included in the microgrid powering a plant for advanced green technologies is presented. The microgrid is powered by a 730–kW photovoltaic source and four energy storage systems. The hydrogen storage system consists of a water demineralizer, a 22.3–kW alkaline electrolyzer generating hydrogen, its AC–DC power supply, 99.9998% hydrogen purifier, 200-bar compressor, 200–L gas storage cylinders, a 31.5–kW proton–exchange–membrane fuel cell running on hydrogen, its DC–AC power conditioning system. The whole system is housed in three containers provided with anti–salt filters to remove brine. The whole system is controlled by the microgrid system supervisor. Operative tests at nominal power show that the round-trip efficiency of the hydrogen energy storage system at full power is ca. 10% in a pure electric operation and ca. 24% in a heat cogeneration operation. At half power these values reduce to 9.5% and 18%, respectively. [Display omitted] • A hydrogen energy storage system operating within a microgrid is described. • The system consists of three sub-systems: H 2 production, storage and conversion. • A detailed description of the technical devices in each sub-system is presented. • The nominal data and performance of each sub-system are evaluated. • The experimental performance of each sub-system is reported and discussed. [ABSTRACT FROM AUTHOR]

For vehicle-mounted high-pressure hydrogen storage cylinders, impact resistance is an important indicator. This work aims at building a model of 70 MPa composite fully wound Ⅳ cylinder around T800 carbon fiber material, investigating the law of transient changes in the body of the bottle under different velocity impacts and the source of risk of bursting. Through millisecond impact analysis, the energy transfer path and transformation trend inside the cylinder are obtained. Meanwhile, it was found that there was a clear pattern of positive correlation between the tensile and compressive stresses generated by the difference between the internal pressure of the bottle and the impact pressure. The final results show that after the impact, the failure occurred firstly at the inner wall of the fiber corresponding to the impact point, and the fiber damage spreads in all directions. The thickness of the failure pavement increases from the inside to the outside. • Exploration of the pressure change law when the hydrogen storage cylinder is subjected to high-speed impact. • Demonstrate the trend of energy transfer during gas cylinder impact using millisecond impact analysis. • Effect of hydrogen pressure inside the cylinder on impact. • The impact is more damaging to the fibers on the inner wall of the cylinder, and the fiber layer fails from the inside out. [ABSTRACT FROM AUTHOR]

The largest inorganic, gas-phase reservoir of chlorine atoms in the atmosphere is hydrogen chloride (HCl), but challenges in quantitative sampling of this compound cause difficulties for obtaining high-quality, high-frequency measurements. In this work, tunable infrared laser direct absorption spectroscopy (TILDAS) was demonstrated to be a superior optical method for sensitive, in situ detection of HCl at the 2925.89645 cm -1 absorption line using a 3 µ m inter-band cascade laser. The instrument has an effective path length of 204 m, 1 Hz precision of 7–8 pptv, and 3 σ limit of detection ranging from 21 to 24 pptv. For longer averaging times, the highest precision obtained was 0.5 pptv with a 3 σ limit of detection of 1.6 pptv at 2.4 min. HCl-TILDAS was also shown to have high accuracy when compared with a certified gas cylinder, yielding a linear slope within the expected 5 % tolerance of the reported cylinder concentration (slope = 0.964 ± 0.008). The use of heated inlet lines and active chemical passivation greatly improve the instrument response times to changes in HCl mixing ratios, with minimum 90 % response times ranging from 1.2 to 4.4 s depending on inlet flow rate. However, these response times lengthened at relative humidities >50 %, conditions under which HCl concentration standards were found to elicit a significantly lower response (-5.8 %). The addition of high concentrations of gas-phase nitric acid (>3.0 ppbv) were found to increase HCl signal (<10 %), likely due to acid displacement with HCl or particulate chloride adsorbed to inlet surfaces. The equilibrium model ISORROPIA suggested a potential of particulate chloride partitioning into HCl gas within the heated inlet system if allowed to thermally equilibrate, but field results did not demonstrate a clear relationship between particulate chloride and HCl signal obtained with a denuder installed on the inlet. [ABSTRACT FROM AUTHOR]

The multi-scheme chemical ionisation inlet 1 (MION1) allows fast switching between measuring atmospheric ions without chemical ionisation and neutral molecules by multiple chemical ionisation methods. In this study, the upgraded multischeme chemical ionisation inlet 2 (MION2) is presented. The new design features improved ion optics that increase the reagent ion concentration, a generally more robust operation and the possibility to run multiple chemical ionisation methods with the same ionisation time. To simplify the regular calibration of MION2, we developed an open-source flow reactor chemistry model (MARFORCE) to quantify the chemical production of sulfuric acid (H2SO4), hypoiodous acid (HOI) and hydroperoxyl radical (HO2). MARFORCE simulates convection-diffusion-reaction processes inside typical cylindrical flow reactors with uniform inner diameters. The model also provides options to simulate the chemical processes 1) when two flow reactors with different inner diameters are connected together and 2) when two flows are merged into one (connected by a Y-shape tee), but with reduced accuracy. Additionally, the chemical mechanism files in the model are compatible with the widely-used Master Chemical Mechanism, thus allowing future adaptation to simulate other chemical processes in flow reactors. We further carried out detailed characterisation of the bromide (Br-) and nitrate (NO3-) chemical ionisation methods with different ionisation times. We calibrated H2SO4, HOI and HO2 by combining gas kinetic experiments with the MARFORCE model. Sulfur dioxide (SO2), water (H2O) and molecular iodine (I2) were evaluated using dilution experiments from a gas cylinder (SO2), dew point mirror measurements (H2O), and a derivatization approach in combination with high-performance liquid chromatography quantification (I2), respectively. We find that the detection limit is negatively correlated with the fragmentation enthalpy of the analyte-reagent ion (Br-) cluster, i.e., a stronger binding (larger fragmentation enthalpy) leads to a lower detection limit. Additionally, a moderately longer reaction time enhances the detection sensitivity thus decreasing the detection limit. For example, the detection limit for H2SO4 is estimated to be 2.9x104 molec. cm-3 with a 300 ms ionisation time. A direct comparison suggests that this is even better than the widely-used Eisele-type chemical ionisation inlet. While the NO3- chemical ionisation method is generally more robust, we find that the Br- chemical ionisation method (Br--MION2) is significantly affected by air water content. Higher air water content results in lower sensitivity for HO2 and SO2 within the examined conditions. On the other hand, a steep sensitivity drop of H2SO4, HOI and I2 is only observed when the dew point is greater than 0.5-10.5 °C (equivalent to 20-40 % RH; calculated at 25 °C hereafter). Future studies utilising atmospheric pressure Br- chemical ionisation method, including Br--MION2, should carefully address the humidity effect on a molecular basis. By combining methods such as water-insensitive NO3--MION2 with Br--MION2, MION2 should be able to provide greater details of air composition than either of these methods alone. Combining instrument voltage-scanning, chemical kinetic experiments and quantum chemical calculations, we find that the HIO3 detection is not interfered with by iodine oxides under atmospherically relevant conditions. The IO3-, HIO3NO3- and HIO3Br- ions measured using the Br- and NO3- chemical ionisation methods are primarily, if not exclusively, produced from gaseous HIO3 molecules. [ABSTRACT FROM AUTHOR]

Ammonia, as an alternative fuel for internal combustion engines, can achieve nearly zero carbon emissions. Although the development of the pure ammonia engine is limited by its poor combustion characteristics, ammonia–hydrocarbon mixed combustion can effectively improve the combustion of ammonia fuel. With the increase in the ammonia fuel proportion in the fuel mixture, a large number of nitrogen oxides (NOX) and unburned ammonia may be discharged, which have a poor impact on the environment. In this study, the performance of selective catalytic reduction (SCR) aftertreatment technology in reducing NOX and ammonia emissions from ammonia–diesel dual-fuel engines was investigated using simulation. A good cross-dimensional model was established under the coupling effect, though the effect of a single-dimensional model could not be presented. The results show that when the exhaust gas in the engine cylinder is directly introduced into the SCR without additional reducing agents such as urea, unburned ammonia flowing into SCR model is in excess, and there will be only ammonia at the outlet; however, if the unburned ammonia fed into the SCR model is insufficient to reduce NO, the ammonia concentration at the outlet will be 0. NOX can be 100% effectively reduced to N2 under most engine conditions; thus, unburned ammonia in exhaust plays a role in reducing NOX emissions from ammonia–diesel dual-fuel engines. However, when the concentration of unburned ammonia in the exhaust gas of an ammonia–diesel dual-fuel engine is large, its ammonia emissions are still high even after the SCR. In addition, the concentrations of N2O after SCR do not decrease, but increase by 50.64 in some conditions, the main reason for which is that by the action of the SCR catalyst, NO2 is partially converted into N2O, resulting in an increase in its concentration at the SCR outlet. Adding excessive air or oxygen into the SCR aftertreatment model can not only significantly reduce the ammonia concentration at the outlet of the model without affecting the NOX conversion efficiency of SCR, but inhibit N2O production to some extent at the outlet, thus reducing the unburned ammonia and NOX emissions in the tail gas of ammonia–diesel dual-fuel engines at the same time without the urea injection. Therefore, this study can provide theoretical guidance for the design of ammonia and its mixed-fuel engine aftertreatment device, and provide technical support for reducing NOX emissions of ammonia and its mixed fuel engines. [ABSTRACT FROM AUTHOR]

Fluxes of oxygen (O 2) and carbon dioxide (CO 2) in and out of the atmosphere are strongly coupled for terrestrial biospheric exchange processes and fossil fuel combustion but are uncoupled for oceanic air–sea gas exchange. High-precision measurements of both species can therefore provide constraints on the carbon cycle and can be used to quantify fossil fuel CO 2 (ffCO 2) emission estimates. In the case of O 2 , however, due to its large atmospheric mole fraction (∼20.9 %) it is very challenging to measure small variations to the degree of precision and accuracy required for these applications. We have tested an atmospheric O 2 analyser based on the principle of cavity ring-down spectroscopy (Picarro Inc., model G2207- i), both in the laboratory and at the Weybourne Atmospheric Observatory (WAO) field station in the UK, in comparison to well-established, pre-existing atmospheric O 2 and CO 2 measurement systems. In laboratory tests analysing dry air in high-pressure cylinders, we found that the best precision was achieved with 30 min averaging and was ±0.5 ppm (∼±2.4 per meg). Also from continuous measurements from a cylinder of dry air, we found the 24 h peak-to-peak range of hourly averaged values to be 1.2 ppm (∼5.8 per meg). These results are close to atmospheric O 2 compatibility goals as set by the UN World Meteorological Organization. However, from measurements of ambient air conducted at WAO we found that the built-in water correction of the G2207- i does not sufficiently correct for the influence of water vapour on the O 2 mole fraction. When sample air was dried and a 5-hourly baseline correction with a reference gas cylinder was employed, the G2207- i 's results showed an average difference from the established O 2 analyser of 13.6±7.5 per meg (over 2 weeks of continuous measurements). Over the same period, based on measurements of a so-called "target tank", analysed for 12 min every 7 h, we calculated a repeatability of ±5.7±5.6 per meg and a compatibility of ±10.0±6.7 per meg for the G2207- i. To further examine the G2207- i 's performance in real-world applications we used ambient air measurements of O 2 together with concurrent CO 2 measurements to calculate ffCO 2. Due to the imprecision of the G2207- i , the ffCO 2 calculated showed large differences from that calculated from the established measurement system and had a large uncertainty of ±13.0 ppm, which was roughly double that from the established system (±5.8 ppm). [ABSTRACT FROM AUTHOR]

The investigation deals with the study of the effect of the purity level of carbon dioxide shielding gas on the metal active gas weld quality. Studied 99.78 %, 99.95 %, and 99.97 % purity levels of carbon dioxide shielding gas. Factors considered were related to shielding gas purity, moisture, Sulphur, and oxygen content. Welded samples were subjected to ultrasonic testing to assess weld quality. With the reduction in purity level below 99.9 %, it was observed that the weld defect percentage increased in both lab trials and mass manufacturing jobs. The defects recorded were 5% higher when jobs were welded using carbon dioxide supplied from a gas cylinder than that supplied from liquid cryogenic bullets; this established that a higher purity level could be maintained in cryogenic storage and transport of shielding gases. This states helpful references to manufacturing industries for selecting the purity level of shielding gas, with the objective of rework reduction. [ABSTRACT FROM AUTHOR]

This paper presents the numerical and experimental results of the mechanical and microstructural properties of liquefied petroleum gas cylinders from local sources. The tensile strength, burst and fracture toughness of the materials were also investigated. The results show that the carbon content for all samples averaged ~0.22 wt% and manganese ~0.76 wt% and the microstructure was largely pearlitic. The tensile strength showed that LPG-C3 recorded high tensile strength of ~ 611 MPa and hardness of ~ 200 HV while LPG-C5 recorded low tensile strength of ~ 450 MPa. The finite element analysis (FEA) showed fracture toughness of ~5 × 105 MPa.mm0.5 for LPG-C2 and the energy release rate of ~2 × 106J/m² for LPG-C5. All samples exhibited high resilience to crack propagation which showed ductile fracture after tensile test. The implications of the results are discussed to elaborate on the influence of carefully controlling the alloying elements of LPG cylinder materials on their mechanical and microstructures during fabrication. [ABSTRACT FROM AUTHOR]

Objective This study aims to investigate the influences of aluminum alloy lining structure parameters on the overall fatigue performance of type Ⅲ hydrogen cylinder, and obtain the optimal design scheme of lining which can improve the long-term performance of gas cylinder. Methods Based on orthogonal test and numerical simulation, the fatigue life of composite material gas cylinder is calculated by Brown-Miller algorithm. Through correlation analysis, the influences of cylinder wall thickness, length-diameter ratio and head ellipsoid ratio on fatigue performance are comprehensively evaluated, and the main factor is confirmed to be cylinder wall thickness. Based on Goodman average stress correction equation, the variation of lining stress amplitude with the increase of wall thickness is analyzed. The optimal design is verified by the normal temperature pressure cycle test. Results The actual fatigue life of cylinders is in good agreement with the simulation results, and the final cycle times are 5.7%, which is different from the simulation results. The fatigue failure position of gas cylinder appears in the lining cylinder body, and the fatigue failure of aluminum alloy lining is earlier than that of fiber winding layer. Conclusions The fatigue life of the optimized composite material gas cylinder is 44.7% longer than that of the standard. It is feasible to optimize the lining structure parameters of type III hydrogen cylinder by orthogonal test. [ABSTRACT FROM AUTHOR]

The flow characteristics of propellant gases inside the gas cylinder of the weapon gasoperated mechanism, applied to the UK-59 machine gun, are studied. Computational Fluid Dynamics (CFD) in ANSYS Fluent is used for the simulation of flow through the gas port from the barrel bore to the gas cylinder and back. The study's findings are presented along with the piston law of motion and thermodynamic quantities of gases inside the cylinder, specifically the pressure, temperature, and velocity distribution of gases in the cylinder for various piston displacements. The experiment was carried out to specify the pressure of the gases in the cylinder, as well as the displacement of the piston. The experimentally obtained values are compared to the simulation results with a very good agreement. [ABSTRACT FROM AUTHOR]

Background: Our understanding of the physiological responses of rice inflorescence (panicle) to environmental stresses is limited by the challenge of accurately determining panicle photosynthetic parameters and their impact on grain yield. This is primarily due to the lack of a suitable gas exchange methodology for panicles and non-destructive methods to accurately determine panicle surface area. Results: To address these challenges, we have developed a custom panicle gas exchange cylinder compatible with the LiCor 6800 Infra-red Gas Analyzer. Accurate surface area measurements were determined using 3D panicle imaging to normalize the panicle-level photosynthetic measurements. We observed differential responses in both panicle and flag leaf for two temperate Japonica rice genotypes (accessions TEJ-1 and TEJ-2) exposed to heat stress during early grain filling. There was a notable divergence in the relative photosynthetic contribution of flag leaf and panicles for the heat-tolerant genotype (TEJ-2) compared to the sensitive genotype (TEJ-1). Conclusion: The novelty of this method is the non-destructive and accurate determination of panicle area and photosynthetic parameters, enabling researchers to monitor temporal changes in panicle physiology during the reproductive development. The method is useful for panicle-level measurements under diverse environmental stresses and is sensitive enough to evaluate genotypic variation for panicle physiology and architecture in cereals with compact inflorescences. [ABSTRACT FROM AUTHOR]

The largest inorganic, gas phase reservoir of chlorine atoms in the atmosphere is hydrogen chloride (HCl), but the challenges in quantitative sampling of this compound cause difficulties for obtaining high-quality, high-frequency measurements. In this work, tunable infrared laser direct absorption spectroscopy (TILDAS) was demonstrated to be a superior optical method for sensitive, in situ detection of HCl at the 2925.89645 cm-1 absorption line using a 3 μm interband cascade laser. The instrument has an effective path length of 204 m, 1 Hz precision of 7-8 pptv, and 3σ limit of detection ranging from 21-24 pptv. For longer averaging times, the highest precision obtained was 0.5 pptv and 3σ limit of detection of 1.6 pptv at 2.4 minutes. HCl TILDAS was also shown to have high accuracy when compared with a certified gas cylinder, yielding a linear slope within the expected 5% tolerance of the reported cylinder concentration (slope = 0.964 ± 0.008). The use of heated inlet lines and active chemical passivation greatly improve the instrument response times to changes in HCl mixing ratios, with minimum 90% response times ranging from 1.2 - 4.4 s, depending on inlet flow rate. However, these response times lengthened at relative humidities > 50%, conditions under which HCl concentration standards were found to elicit a significantly lower response (-5.8%). The addition of high concentrations of gas phase nitric acid (> 4.0 ppbv) were found to increase HCl signal (< 10%), likely due to acid displacement with HCl or particulate chloride adsorbed to inlet surfaces. The equilibrium model ISORROPIA suggested a potential of particulate chloride partitioning into HCl gas within the heated inlet system if allowed to thermally equilibrate, but field results did not demonstrate a clear relationship between particulate chloride and HCl signal obtained with a denuder installed on the inlet. [ABSTRACT FROM AUTHOR]

This study optimized the laminate structure of a composite cylinder under the constraint of minimum layup thickness. Based on the progressive damage theory, a finite element model of the cylinder was established, and the NOL ring tensile test was used to verify the accuracy of the damage theory. The winding angle, the number of layers, and the helical/hoop ratio (the stacking sequence) were selected as the optimization factors, and the burst pressure value was used to evaluate the quality of the laminate structure. Then the orthogonal experiments were designed by RSM. Combined with FEA, the function model of the burst pressure of the gas cylinder and each optimization factor was established to obtain the optimal layering scheme, satisfying the minimum burst pressure. In addition, finite element analysis was used to verify the optimal scheme, demonstrating that the error of the burst pressure predicted by the quadratic model established by the response surface design was not more than 5%. This study provides a faster and more efficient optimization method for the optimization design of composite gas cylinder layers. [ABSTRACT FROM AUTHOR]

In the semiconductor industry, hydrogen is used with many other hazardous and dangerous substances with flammable, toxic, and corrosive properties. In order to safely handle them, convenient-to-use gas cabinets are often required. As known well, hydrogen is highly flammable and explosive, and risk analysis needs to safely use the gas in the cabinets. In this study, overpressure and impact according to various gas cabinet conditions were measured when hydrogen leaks in the gas cabinet, and the effect of overpressure on the protective wall was simulated. For the research, a demonstration experiment was conducted by custom manufacturing a gas cylinder cabinet identical to the standard used in the field, and the protection performance analysis was performed by reverse-engineering it through 3D scanning. As a result of the demonstration experiment, the maximum pressure at the time of hydrogen gas explosion in the gas cylinder cabinet was measured at 0.3 bar. After calculating the detonation pressure propagation profile using the TNT equivalence method, the protective performance of the protective wall was confirmed using AUTODYN. The maximum stress of the concrete and the maximum stress of the reinforcing bar due to the explosion in the gas cylinder cabinet were calculated to be 30.211 MPa and 112.88 MPa, respectively, which do not exceed the tensile strength of concrete and the yield strength of the reinforcing bar. This result is expected to be of great help to the development of the semiconductor industry by suggesting the rationale for mitigating the firewall when changing the semiconductor layout. [ABSTRACT FROM AUTHOR]

A portable propane container with a name-plate soldered onto it exploded in service. When the vessel was inspected afterwards, it was found to have developed a crack in the top end plate. A portion of the end plate cut out to include the midlength and one termination of the crack was examined microscopically. This revealed that the crack was associated with intergranular penetration by molten metal. The microstructure in general was indicative of a good-quality mild steel. It was evident from that solder that was responsible for the penetration and that fused brass from the hand wheel had not played any part. Tensile stress was present at the time of the failure sufficiently high to enable solder penetration to take place. The use of soft solder as a medium for attaching name-plates directly on to stressed steel parts is not recommended. It would be preferable to use a welded-on patch plate or to employ one of the high-strength, non-metallic adhesives. [ABSTRACT FROM AUTHOR]

Current methods of controlling gas in the headspace involve constant speed aeration and proportional-integral-differential (PID) controlled aeration using improved monitoring devices or gas cylinders. However, these approaches are restricted and inconvenient to use. In this study, we propose a method to control the CO 2 concentration in the headspace while maintaining the convenience of shake-flask culture. A combination of a non-electric bellows pump for shake-flask (NeBP-sf) and a CO 2 incubator was used to control the flask gas phase by shaking without additional external power. The CO 2 half-life, as an indicator of the ventilation ability of the system, was measured using a circulation direct monitoring and sampling system, and the NeBP-sf was optimised. The ventilation capacity varied depending on the shaking speed, and under optimal conditions, was 10 min compared with 45 min when only a breathable culture plug was used. In conventional microbial shaking culture, the CO 2 concentration in the flask gas phase remained higher than the 5% set-value with a maximum of 9%, resulting in a large concentration difference with the set point. Therefore, the ventilation capacity of the conventional shake-flask culture was insufficient for aerobic culture. Cultivation of Escherichia coli and Lactiplantibacillus plantarum using the system showed no significant difference between the set point and real point values. Thus, the system combined an NeBP-sf and a gas incubator built-in shaking table to achieve the reproducibility of gas control while maintaining a high level of convenience. [Display omitted] • Gas-phase control in flask headspaces required complicated monitoring device. • We developed NeBP-sf with a shaking CO 2 incubator to control the flask gas phase. • The system maintains reproducible gas-control and is convenient to use. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tracer-inverse calculation method for parameters of air-immobile regions in piles. • Higher β or ω slows breakthrough and lessens peak concentration of tracer in BTCs. • 39%/46% of gas pores are air-immobile regions in composting piles during two phases. • New protocol predicts temporal change of O 2 concentration in exhaust or matrix well. Air-immobile regions in composting piles obstruct O 2 mass transport and exacerbate the formation and emission of harmful off-gases. However, effective methods for measuring the parameters of these air-immobile regions are lacking. With quartz sand piles, this study first adjusted the circumstances of a gas tracer test (gas tracer, its injection volume, and chamber type) using the two-region model (TRM). The effects of β (proportional coefficient of gas in the air-mobile region) and ω (mass exchange coefficient) on the breakthrough curves (BTCs) of the gases were then explored. Finally, an inverse calculation method was used to measure the feature parameters of air-immobile regions in two composting piles (temperature-increasing and thermophilic phases) and estimate the O 2 concentrations in different composting piles (50, 100, 200 cm whole height; layers of 50, 100, 200 cm height in a 200-cm high pile). The results showed that the optimal conditions were achieved when 100 mL helium (He) as the gas tracer and a cylinder with a height/diameter ratio of 3 as the chamber were used. With the simulating composting piles, increasing β or ω slowed breakthrough and decreased peak concentration in BTCs of a gas tracer. Tracer-inverse calculation protocol can be used to efficiently estimate the volume ratios of air-immobile regions (φ) and first-order mass transfer coefficient (α), with the values of 39%/46% and 0.001/0.006 min−1 in the composting piles during temperature-increasing /thermophilic phase. The TRM also predicted the O 2 concentration in the off-gas or air-mobile/immobile regions of the temperature-increasing-phase composting piles. [ABSTRACT FROM AUTHOR]

Fluxes of oxygen (O2) and carbon dioxide (CO2) in and out of the atmosphere are strongly coupled for terrestrial biospheric exchange processes and fossil fuel combustion but are uncoupled for oceanic air-sea gas exchange. High-precision measurements of both species can therefore provide constraints on the carbon cycle and can be used to quantify fossil fuel CO2 (ffCO2) emission estimates. In the case of O2, however, due to its large atmospheric mole fraction of O2 (~20.9 %) it is very challenging to measure small variations to the degree of precision and accuracy required for these applications. We have tested an atmospheric O2 analyser based on the principle of cavity ring-down spectroscopy (Picarro Inc., model G2207- i), both in the laboratory and at the Weybourne Atmospheric Observatory (WAO) field station in the UK, in comparisons to well-established, pre-existing atmospheric O2 and CO2 measurement systems. In laboratory tests analysing air in high-pressure cylinders, from the Allan deviation we calculated a precision of ± 1 ppm (1σ standard deviation of 300 seconds mean), and a 24-hour peak-to-peak range of hourly averaged values of 1.2 ppm. These results are close to atmospheric O2 compatibility goals as set by the UN World Meteorological Organization. From measurements of ambient air conducted at WAO we found that the built-in water correction of the G2207-i does not sufficiently correct for the influence of water vapour on the O2 mole fraction. When sample air was pre-dried and employing a 5-hourly baseline correction with a reference gas cylinder, the G2207-i’s results showed an average difference from the established O2 analyser of 13.6 ± 7.5 per meg (over two weeks of continuous measurements). Over the same period, based on measurements of a so-called “target tank” (sometimes known as a “surveillance tank”), analysed for 12 minutes every 7 hours, we calculated a repeatability of ± 5.7 ± 5.6 per meg and a compatibility of ± 10.0 ± 6.7 per meg for the G2207-i . To further examine the G2207-i’s performance in real-world applications we used ambient air measurements of O2 together with concurrent CO2 measurements to calculate ffCO2. Due to the imprecision of the G2207-i, the ffCO2 calculated showed large differences from that calculated from the established system, and had a large uncertainty of ± 13.0 ppm, which was roughly double that from the established system (± 5.8 ppm). [ABSTRACT FROM AUTHOR]

Carbon monoxide‐releasing molecules (CORMs) can offer a safer alternative to CO delivery than the use of CO gas cylinders. Upon treatment with an amine base, S‐aryl thioformates ("thioCORMates") release CO nearly quantitatively at room temperature, a gas which can then be harnessed for carbonylative cross‐coupling, biological study, or inorganic synthesis. These bench‐stable molecules are easily synthesized from the corresponding thiophenol and can be electronically tuned to release CO at different rates‐from less than 1 min to greater than 1 h‐offering a practical alternative to existing CORM technology. Finally, isotopically labeled 13CO can be conveniently generated and used, with the thioCORMate synthesized from 13C‐formic acid. [ABSTRACT FROM AUTHOR]

The fast charging process of high-pressure gas storage cylinders is accompanied by high temperature rise, which potentially induces the failure of solid materials inside the cylinders and the underfilling of the cylinders. A two-dimensional (2D) axisymmetric model simulated the charging process of hydrogen storage cylinders with a rated working pressure of 35 MPa and a volume of 150 L. During filling, the highest temperature rise inside the cylinder occurs at the bottom part of the cylinder, and the state of charge (SOC) is 46.4% after filling. This temperature rise can be reduced by precooling the injected hydrogen, and the highest SOC can reach 95.7% after injection. The SOC in the cylinder gradually increases with a decrease in the temperature of the hydrogen injection. The maximum SOC increase is 49.3%. For safety and the SOC exceeding 90%, the hydrogen gas should be precooled to below −10 °C, and the SOC could achieve more than 90.3%. The internal structure of the hydrogen cylinder was further optimized without a precooling condition. The selected length ratios were 25%, 50%, and 75%. Compared with the initial scheme, the SOC in the optimization scheme increased by 16%, 38.7%, and 40.1%. [ABSTRACT FROM AUTHOR]

Since COVID-19 was declared as a pandemic by World Health Organization in March 2020, 169,682,828 cases have been reported worldwide, with 151,416,570 recovered, and 3,526,647 deaths by May 28, 2021. Oxygen gas cylinders demand is booming globally due to its need for COVID-19's for intensive care. Thus, it is critical for hospitals to know exactly the time of receiving oxygen gas cylinders since this will help in minimizing the fatality rate. In this regards, this paper proposes a Multilayer Perceptron Neural Network-based model to predict the delivery time of oxygen gas cylinders for a real-life logistics data from a company that delivers oxygen gas cylinders to all cities around Saudi Arabia. Besides, Multilayer Perceptron Neural Network is benchmarked to supported vector machine and multiple linear regression. Although all the considered models have the ability to provide accurate prediction results, the findings indicate that the proposed supported vector machine and Multilayer Perceptron Neural Network model provide better prediction results. The analysis was achieved through a methodology to identify factors with the highest impact and build a neural network model. The model was further optimized to identify the best order and select the best subset of input variables. The analysis showed that the neural network model can be used effectively to estimate the delivery time of oxygen gas cylinders. The model illustrated high accuracy of prediction by comparing the predicted values to the actual values. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate on the effect of different injection strategies on the combustion and emission characteristics in a diesel engine with fueled ethanol-butan-2-ol-diesel fuel blends. The most critical problem in the use of fossil-based diesel fuel (FBDF) and ethanol mixtures as an alternative fuel is the phase separation that occurs in a very short time. Therefore, there is a need to use a stabilizer to maintain the homogeneity of the mixture for long-term test conditions. In this study, butan-2-ol (2-butanol) was added to the fuel mixtures as a co-solvent to prevent the phase separation in ethanol-FBDF mixtures. It was observed that the homogeneity of the ethanol and FBDF mixtures was ensured for a long time by adding butan-2-ol up to 20% of the ethanol in the mixture. In the experiments, three different states (main, 5% pilot and 10% pilot) were developed by changing the fuel injection rate shapes. Engine tests have been performed by spraying a total of 45 mg fuel for each fuel per cycle and by charging fresh air into the cylinder at constant temperature and pressure conditions. As the results of this study, the highest maximum cylinder gas pressure with FBDF was observed in a 10% pilot injection application. With the use of ethanol-butan-2-ol-FBDF blends, a decrease in CO, CO2 and NH3 emissions were detected, while NOx emission increased. The lowest combustion noise was seen with 15% ethanol + 3% butan-2-ol + 82% FBDF (E15B3) and 20% ethanol + 4% butan-2-ol + 76% FBDF (E20B4) fuels as 84 dB. A sharp increase in heat release rate was observed using E15B3 in 5% pilot injection compared to FBDF. [ABSTRACT FROM AUTHOR]

The rapid electrical explosion of thin metal wires in a vacuum can completely vaporize the wire and form a fast-expanding gas cylinder of metal atoms. Thin metal wires 12.7 μm in diameter made of W, Mo, Pt, Pd, Ni, Cu, Au, and Al completely evaporated during the first ∼10 ns under the action of a fast-rising current of ∼1 kA/ns. Laser interferometry and the integrated phase technique were used to reconstruct the dynamic atomic polarizability for fully vaporized thin metal wires at 532 and 1064 nm wavelength, calculate the static atomic polarizability, the first dipole-allowed electronic transition energy, and transition wavelengths, and compare our reconstructions with available tabulated values. [ABSTRACT FROM AUTHOR]

This paper proposes an innovative hydrogen-fed high-efficiency X-type rotary engine (XRE) hybrid system by combining with recuperative organic Rankine cycle (RORC). The off-design model is established based on optimal thermo-economic parameters. Furthermore, the effects of key operation parameters on system off-design performance are revealed. Two novel ignition advance angle - crankshaft rotational speed (IAA-CRS) and equivalence ratio - crankshaft rotational speed (ER-CRS) control strategies are proposed by adjusting dual-variables. Meanwhile, the modified sliding pressure control strategy is adopted for RORC to obtain constant final XRE exhaust temperature. Finally, the part-load performance superiorities of novel strategies are revealed. The results show that the novel hybrid system thermal efficiency and LCOE could be improved by 24.2% and declined by 22.2% comparing with standalone XRE, respectively. Compared with crankshaft rotational speed and ignition advance angle, XRE peak cylinder gas temperature and pressure are the most sensitive to equivalence ratio. With decreasing XRE load, the optimal ignition advance angle drops firstly and then keeps constant under IAA-CRS strategy, while the optimal equivalence ratio of ER-CRS strategy drops. The novel ER-CRS strategy is the optimal control strategy, which could perform 2.06% and 7.95% higher thermal efficiency than IAA-CRS and traditional CRS strategies at most. • Hydrogen-fed XRE hybrid system by coupling with RORC using dual operation modes. • 0-D off-design model is established based on optimal thermo-economic parameters. • Crankshaft rotational speed, ignition advance angle, equivalence ratio are studied. • Novel IAA-CRS and ER-CRS strategies by adjusting dual variables are proposed. • Part-load performance advantages of novel control strategies are revealed. [ABSTRACT FROM AUTHOR]

The in-cylinder hydrogen fuel injection method (diesel engine) induces air during the intake stroke and injects hydrogen gas directly into the cylinder during the compression stroke. Fundamentally, because hydrogen gas does not exist in the intake pipe, backfire, which is the most significant challenge to increasing the torque of the hydrogen port fuel injection engine, does not occur. In this study, using the gasoline fuel injector of a gasoline direct-injection engine for passenger vehicles, hydrogen fuel was injected at high pressures of 5 MPa and 7 MPa into the cylinder, and the effects of the fuel injection timing, including the injection pressure on the output performance and efficiency of the engine, were investigated. Strategies for maximizing engine output performance were analyzed. The fuel injection timing was retarded from before top dead center (BTDC) 350 crank angle degrees (CAD) toward top dead center (TDC). The minimum increase in the best torque ignition timing improved, and the efficiency and excess air ratio increased, resulting in an increase in torque and decrease in NO x emissions. However, the retardation of the fuel injection timing is limited by an increase in the in-cylinder pressure. By increasing the fuel injection pressure, the torque performance can be improved by further retarding the fuel injection timing or increasing the fuel injection period. The maximum torque of 142.7 Nm is achieved when burning under rich conditions at the stoichiometric air-fuel ratio. • Air-fuel ratio has a greater effect than mixing time in a direct-injection hydrogen engine. • Torque and efficiency increase as the direct fuel injection timing retards. • NO x emissions decrease as the fuel injection timing is retarded. • Retardation of the fuel injection timing is limited by the fuel injection end point. • Further retarded fuel injection with pressure increase triggers a decrease in efficiency. [ABSTRACT FROM AUTHOR]