Hydrogen liquefaction is an essential section for efficient storage and transportation of hydrogen energy. Both the Claude cycle and Brayton refrigeration cycle are available for large-scale hydrogen liquefaction systems. Two large-scale hydrogen liquefiers with the liquefaction capacity of 120 t/d based on the Brayton refrigeration cycle and the Claude cycle, respectively, are analyzed and compared in this study. Sensitivity analysis is used to optimize the parameters of two liquefaction systems in HYSYS. According to the results, the exergy loss and specific energy consumption of the Claude liquefier are 18.98 MW and 5.62 kWh/kgLH, which are 6.6% and 4.4% less than those of the Brayton liquefier, respectively. Exergy analysis reveals the exergy loss of compression and expansion systems in the Claude liquefier is less than that of the Brayton liquefier, while the exergy loss of the throttle valve in the Claude liquefier is more notable. In addition, the molar flow rate of hydrogen use... [more]

This study proposed a novel continuous roll-forming process of elastomer molds, which can control the deformation of the mold using the rolling belt stack combination method. This study analyzed various rolling belt combinations, assembled the system based on simulation and experimental data according to the deformation requirement design, and obtained a controllable microstructure mold rolling belt with tensile deformation. Mold thickness and microstructure size are key microstructure mold deformation parameters. This study designed and assembled a controllable microstructure mold rolling belt-type imprint molding system and conducted a series of experiments. The impact and application of different experimental system operation procedures and fabrication methods of the auxetic structure rolling belt on replication molding were analyzed. The innovative controllable microstructure mold rolling belt-type imprint replication molding technique proposed in this study had a stable and contro... [more]

Vitamin D (VitD) is essential for health and preventing diseases. This study aimed to investigate the possible association between VitD status and health status in 306 Libyan male and female young adults (18−25 Y) and adults (26−65 Y). There were 89.54% of subjects that had VitD levels below normal (<30 ng/mL), of which 45.42% were VitD deficient (<10 ng/mL) and 44.12% were VitD insufficient (10−29.9 ng/mL). VitD deficiency was associated with higher fasting blood sugar (FBS), low-density lipoprotein (LDL), and triacylglycerol (TAG) levels. Young adults had lower VitD levels than adults, which was associated with some health conditions. VitD insufficiency was associated with higher body mass index (BMI) values in adults, especially females, with higher FBS levels in adult males and higher hemoglobin A1c (HbA1c) levels in adult females. VitD deficiency in young adults was associated with higher TAG levels (more likely in adults) and lower high-density lipoprotein (HDL) values. Fur... [more]

The solid heat carrier moving bed with internals is an advanced oil shale retorting technology. However, the retorting gas produced by pyrolysis is generally used as fuel gas. The content of CO, H2, and CH4 in the retorting gas is high, and direct combustion leads to resource waste and environmental pollution. In addition, heteroatomic sulfur and nitrogen, as well as unsaturated hydrocarbons, reduce the quality of shale oil. To solve these problems, this paper proposed a chemical looping enhanced oil shale-to-liquid fuels (CLeSTL) process. The chemical looping hydrogen production technology is applied to convert retorting gas to hydrogen, and the hydrogen produced is used for shale oil hydrogenation to improve the oil quality. In this paper, the new process is modeled and simulated; then technoeconomic analysis is carried out. Technical analysis shows that shale oil yield is increased from 65% to 95.7% and the yield of light fraction is increased from 20% to 64%−83%. Economic analysis... [more]

One important application of polymer/graphene nanocomposites is in membrane technology. In this context, promising polymer/graphene nanocomposites have been developed and applied in the production of high-performance membranes. This review basically highlights the designs, properties, and use of polymer/graphene nanocomposite membranes in the field of gas separation and purification. Various polymer matrices (polysulfone, poly(dimethylsiloxane), poly(methyl methacrylate), polyimide, etc.), have been reinforced with graphene to develop nanocomposite membranes. Various facile strategies, such as solution casting, phase separation, infiltration, self-assembly, etc., have been employed in the design of gas separation polymer/graphene nanocomposite membranes. The inclusion of graphene in polymeric membranes affects their morphology, physical properties, gas permeability, selectivity, and separation processes. Furthermore, the final membrane properties are affected by the nanofiller content,... [more]

Multi-phase flow, characterised by the presence of both liquid and gas phases, often occurs in riser pipes during oil extraction. These flows can be problematic because they can cause oscillations due to the formation of bubbles within the pipes, which can negatively impact the safety and efficiency of offshore production operations. One solution to this problem is to use a gravitational oil separator, which is designed to dampen these oscillations. The separator is equipped with a control system that uses liquid level and gas pressure sensors to stabilise the flow by adjusting the positions of its valves. This paper presents the use of a specific type of model-based predictive controller to control the level and pressure of a biphasic oil separator, particularly in the presence of slug disturbances. The designs of the separator model and controller are discussed in detail, with a focus on the advantages of using an unrestricted horizon predictive controller, such as its ability to mak... [more]

In this study, modified granular activated carbon (GAC) and immobilized cells were used to improve the biological efficiency of high-ammonia-nitrogen wastewater treatment using microorganisms. The results showed that using sodium-hydroxide-modified activated carbon (NaOH-GAC) greatly increased the immobilized numbers of the ammonia-oxidizing bacteria Alcaligenes sp. TD-94 and Paracoccus sp. TD-10. Using NaOH-GAC increased the number of immobilized cells by 63.27% over GAC. Compared with free cells, those immobilized on modified activated carbon were more effective in the removal of high ammonia nitrogen levels from wastewater. In wastewater with an ammonia nitrogen concentration of 100 mg·L−1, the ammonia nitrogen removal efficiencies of NaOH-GAC-immobilized cells and free cells within 24 h were 100% and 4.17%, respectively. After 45 cycles, NaOH-GAC-immobilized cells maintained an ammonia nitrogen removal efficiency of 79.24%. After 70 days of storage at 4 °C, the ammonia nitrogen rem... [more]

In view of the problems of heavy work, long cycle, high cost and low efficiency in the process of indirect determination of coal seam gas content, the basic gas parameters and coal quality indexes of 24 coal samples from 5 coal mines in the Hancheng area of Shanxi Province are measured by the laboratory measurement method. The raw coal gas content−gas desorption index of drilling cuttings (W−K1) relationship model is characterized by logarithmic function. Using SPSS data analysis software, a stepwise multiple linear regression method is used for statistical analysis. The results show that the factors that have a significant impact on the regression slope C in the W−K1 relationship model are gas adsorption constant (a), apparent density (ARD), initial velocity of gas diffusion (Δp) and consistent coefficient (f). The factors that have a significant impact on the regression constant D are Δp and atmospheric adsorption (Q). Then, the mathematical model of rapid prediction of coal seam gas... [more]

Clarifying the water invasion rule of edge and bottom water reservoirs can adjust the reservoir development mode and improve the recovery factor of edge and bottom water reservoirs in a timely manner. Influenced by the size of a reservoir water body, energy intensity and reservoir seepage capacity, the change model of reservoir water influx basically belongs to the exponential growth model of the GM (1,1) model or the self-constraint growth model of the logistic model. The above two models are used to predict and analyze the water inflow of edge and bottom water reservoirs, respectively, and it is found that the change in water inflow of the reservoir with sufficient edge and bottom water energy is more consistent with the prediction results of the GM (1,1) model, but it has a large error compared to the prediction results of the logistic model. The change in water influx in the reservoir with insufficient edge and bottom water energy is consistent with the prediction results of the lo... [more]

Pinch analysis is vital in optimizing heat exchanger networks (HENs). Targeting methods are used when determining cost effectiveness with pinch analysis. However, the existing targeting methods for the capital cost of HEN are not suitable for wide application scenarios. Therefore, we developed a high-accuracy general capital-cost-targeting method. It is built on a final structure that was evolved from the spaghetti structure of HEN through four loop elimination stages. This structure helps to reduce the prediction deviation of the method. To achieve high adaptability while establishing this method, we considered the different heat exchanger cost categories, different cost laws for one stream pair, and area limitations of heat exchangers that may be encountered in practice. In addition, allowing streams to use individual temperature difference contributions enhances the method’s predictive capacity. The potential defects of the method found in numerical experiments and case studies were... [more]

The input layer, hidden layer, and output layer are three models of the neural processors that make up feedforward neural networks (FNNs). Evolutionary algorithms have been extensively employed in training FNNs, which can correctly actualize any finite training sample set. In this paper, an enhanced marine predators algorithm (MPA) based on the ranking-based mutation operator (EMPA) was presented to train FNNs, and the objective was to attain the minimum classification, prediction, and approximation errors by modifying the connection weight and deviation value. The ranking-based mutation operator not only determines the best search agent and elevates the exploitation ability, but it also delays premature convergence and accelerates the optimization process. The EMPA integrates exploration and exploitation to mitigate search stagnation, and it has sufficient stability and flexibility to acquire the finest solution. To assess the significance and stability of the EMPA, a series of experi... [more]

Annually, 221 million tons of agro-food by-products are generated worldwide, causing diverse environmental issues due to incorrect discharge. Hot trub, spent hops, brewer’s spent grains, and brewer’s spent yeast are the by-products produced in the beer manufacturing chain. These by-products contain fibers, proteins, polyphenols, essential oils, and taste compounds, presenting high possibilities of use as alternative raw materials. In this review, we compiled the knowledge gaps of brewing by-product reuse, from phytochemical compound extractions to concentration approaches, mainly concerning bitter acids and polyphenols. Moreover, we assessed and discussed the emerging technologies and alternative solvents that have allowed for higher extraction yields. We illustrated the importance of purification and concentration steps of non-destructive methods for added value in products from reuse approaches. Finally, we showed the relevance of scale-up and economic feasibility studies in order to... [more]

Sludge pyrolysis is a promising method for treating excess sludge as a by-product of municipal sewage plants, allowing for energy self-sufficiency and resource recovery. Before sludge pyrolysis begins, a few conditioning agents are added to the sludge that promote sludge dewatering. Potassium ferrate (K2FeO4) is applied as a conditioning agent with both cracking and flocculation effects, but the effects of K2FeO4 on the release characteristics of nitrogen, sulfur, and chlorine during sludge pyrolysis have not been elucidated. In this study, we analyzed the sludge pyrolysis characteristics and chemical state changes of N, S, and Cl contaminants in the dewatered sludge after K2FeO4 conditioning before and after pyrolysis. Further, the release characteristics of condensable/noncondensable gases during pyrolysis were assessed using thermogravimetric mass spectrometry (TG-MS) and pyrolysis−gas chromatography/mass spectrometry (Py-GC/MS) analyses before and after conditioning. We found that... [more]

(1) Background: Photodynamic therapy (PDT) involves the selective killing of tumor cells by the generation of reactive oxygen species using a photosensitizer (PS) activated by irradiation. In melanoma, PDT efficiency is altered by several mechanisms, such as the presence of melanin and melanosomes and pro-survival pathways mediated by transcription factors such as: AP-1 (activator protein), MITF (microphthalmia inducible transcription factor), HIF1α (hypoxia inducible factor), and NF-kB (nuclear factor kappa B). The study aimed to investigate the anti-melanoma effects of PDT mediated by meso-5,10,15,20-tetrakis-(4-hydroxyphenyl)-porphyrin (THPP) as a photosensitizer. (2) Methods: Cocultures of melanoma, two human, WM35 and M1−15, and murine B16-F10, with endothelial cells, were used. Cytotoxicity, oxidative damage, angiogenesis markers, and melanogenesis were assessed using colorimetry, flowcytometry, confocal microscopy, spectrophotometry, ELISA, and Western blotting. (3) Results: The... [more]

Programmable Logic Controllers (PLCs), as specialized task-oriented embedded field devices, play a vital role in current industrial control systems (ICSs), which are composed of critical infrastructure. In order to meet increasing demands on cost-effectiveness while improving production efficiency, commercial-off-the-shelf software and hardware, and external networks such as the Internet, are integrated into the PLC-based control systems. However, it also provides opportunities for adversaries to launch malicious, targeted, and sophisticated cyberattacks. To that end, there is an urgent need to summarize ongoing work in PLC-based control systems on vulnerabilities, attacks, and security detection schemes for researchers and practitioners. Although surveys on similar topics exist, they are less involved in three key aspects, as follows: First and foremost, previous work focused more on system-level vulnerability analysis than PLC itself. Subsequently, it was not clear whether their work... [more]

As one of the basic industries in the manufacturing industry, the modeling and evaluation of resource utilization efficiency in the machining process is the premise of energy conservation and consumption reduction in the manufacturing industry. Mechanical processing is the process of using resources to change the shape and performance of the blank to form the workpiece and generate emissions. However, the current research on the utilization of machining process resources, whether focusing on energy efficiency or emissions, cannot provide a comprehensive solution to this problem. Therefore, this paper proposes a Data Envelopment Analysis (DEA) model with a slacks-based measure (SBM) to evaluate the resource utilization efficiency of a machining process with non-expected output. Through the relative effectiveness of DEA, the resource utilization efficiency of each processing process can be compared, which can provide a feasible and specific method for enterprises to evaluate their existi... [more]

The iron and steel industry is a high-energy consumption and high-pollution industry. Energy recovery in its process is of great significance. Converter gas is an important by-product in the process of iron and steel production. It is difficult to take effective measures to recover waste heat from converter gas due to its flammability. In this paper, a new technology is proposed based on waste heat recovery by a filled bulb regenerator. The mathematical model of heat transfer and flow in the compound regenerator for converter gas containing dust is established. The effects of the diameter and concentration of dust to heat transfer and flow are discussed. The results show that the temperature of converter gas declined to 132 °C, and recovery efficiency was above 90% using this technology system. Resistance loss increased by 25% due to the dust; with the increase in the diameter and initial concentration of dust, the heat transfer rate in the regenerator was reinforced. At the entrance o... [more]

Employees work long hours in an environment where the ambient air quality is poor, directly affecting their work efficiency. The concentration of particulate matters (PM) produced by the interior renovation of shopping malls has not received particular attention in Macao. Therefore, this study will investigate the indoor air quality (IAQ), in particular of PM2.5, in large-scale shopping mall renovation projects. This study collected on-site PM data with low-cost portable monitoring equipment placed temporarily at specific locations to examine whether the current control measures are appropriate and propose some improvements. Prior to this study, there were no measures being implemented, and on-site monitoring to assess the levels of PM2.5 concentrations was non-existent. The results show the highest level of PM2.5 recorded in this study was 559.00 μg/m3. Moreover, this study may provide a reference for decision-makers, management, construction teams, design consultant teams, and renova... [more]

The receding globalization has reshaped the logistics industry, while the additional pressure of the COVID-19 pandemic has posed new difficulties and challenges as has the pressure towards sustainable development. Achieving the synergistic development of economic, social, and environmental benefits in the logistics industry is essential to achieving its high-quality development. Therefore, we propose a data-driven calculation, evaluation, and enhancement method for the synergistic development of the composite system of economic, social, and environmental benefits (ESE-B) of the logistics industry. Based on relevant data, the logistics industry ESE-B composite system sequential parametric index system is then constructed. The Z-score is applied to standardize the original index data without dimension, and a collaborative degree model of logistics industry ESE-B composite system is constructed to estimate the coordinated development among the subsystems of the logistics industry’s ESE-B... [more]

With the development of society, users have increasing requirements for the high-quality experience of products. The pursuit of a high profit conversion rate also gradually puts forward higher requirements for product details in the competition. Product providers need to iterate products fast and with a high quality to enhance user viscosity and activity to improve the profit conversion rate efficiently. A/B testing is a technical method to conduct experiments on target users who use different iterative strategies, and observe which strategy is better through log embedding and statistical analysis. Usually, different businesses of the same company are supported by different business systems, and the A/B tests of different business systems need to be operated in a unified manner. At present, most A/B testing systems cannot provide services for more than one business system at the same time, and there are problems such as high concurrency, scalability, reusability, and flexibility. In th... [more]

Reducing carbon emission and raising efficient production are the important goals of modern enterprise production process. The same product can be produced by a variety of equipment, and the carbon emissions and processing time of different equipment vary greatly. Choosing suitable production equipment is an important method for manufacturing enterprises to achieve the efficient emission reduction of production process. However, the traditional production equipment selection mode only gives qualitative results, and it is difficult to provide effective advice for enterprises to choose suitable equipment under the needs of carbon neutrality. To solve this problem, this paper systematically analyzes carbon emission and the time of the turning production process, and a unified calculation model for carbon emission and efficient production of multi-type processing equipment is established. The important point of the article is to research the diversity among between carbon emissions and eff... [more]

Melanoma is a cancer that threatens life and leads to death. Effective detection of skin lesion types by images is a challenging task. Dermoscopy is an effective technique for detecting skin lesions. Early diagnosis of skin cancer is essential for proper treatment. Skin lesions are similar in their early stages, so manual diagnosis is difficult. Thus, artificial intelligence techniques can analyze images of skin lesions and discover hidden features not seen by the naked eye. This study developed hybrid techniques based on hybrid features to effectively analyse dermoscopic images to classify two datasets, HAM10000 and PH2, of skin lesions. The images have been optimized for all techniques, and the problem of imbalance between the two datasets has been resolved. The HAM10000 and PH2 datasets were classified by pre-trained MobileNet and ResNet101 models. For effective detection of the early stages skin lesions, hybrid techniques SVM-MobileNet, SVM-ResNet101 and SVM-MobileNet-ResNet101 wer... [more]

Improved irradiance forecasting ensures precise solar power generation forecasts, resulting in smoother operation of the distribution grid. Empirical models are used to estimate irradiation using a wide range of data and specific national or regional parameters. In contrast, algorithms based on Artificial Intelligence (AI) are becoming increasingly popular and effective for estimating solar irradiance. Although there has been significant development in this area elsewhere, employing an AI model to investigate irradiance in Bangladesh is limited. This research forecasts solar radiation in Bangladesh using ensemble machine-learning models. The meteorological data collected from 32 stations contain maximum temperature, minimum temperature, total rain, humidity, sunshine, wind speed, cloud coverage, and irradiance. Ensemble machine-learning algorithms including Adaboost regression (ABR), gradient-boosting regression (GBR), random forest regression (RFR), and bagging regression (BR) are dev... [more]

A series of computational fluid dynamics−discrete element method (CFD-DEM) simulations were applied to seed flow in horizontal-vertical 90-degree elbows. The performance of one-way and two-way CFD-DEM coupling methods was compared. Additionally, simulated seed velocities were compared to the current pneumatic conveying theory for each coupling method. Simulated field peas (Pisum sativum) were pneumatically conveyed to study the effect of air velocity (20, 25, and 30 m/s), seed rate (0.07, 0.21, and 0.42 kg/s), elbow diameter, D, (48.3, 60.3, and 72.4 mm), and elbow bend radius (1.5D, 2.5D, 3.5D, and 4.5D) on seed attributes (trajectory, velocity, and force). Results showed that seed velocity was significantly different between one-way and two-way coupling. Both methods resulted in nearly identical seed trajectory and force. Overall, simulated seed velocities had a strong correlation to values calculated through the current pneumatic conveyance theory. Dimensional analysis revealed that... [more]

The engine performance and emission characteristics of burning emulsions of soybean oil biodiesel in a compression-ignition diesel engine prepared through the phase inversion temperature method were compared with those of neat soybean oil biodiesel and the emulsion prepared by the mechanical homogenization method. The engine torque was set constantly at 98 N·m with varying engine speeds. The experimental results show that the emulsion prepared by the method of phase inversion temperature had higher O2 and NOx emissions, a higher excess air ratio, a higher exhaust gas temperature, and a higher brake fuel conversion efficiency than the emulsion prepared by the mechanical homogenization method, which had lower CO and CO2 emissions, a lower equivalence ratio, and lower brake-specific fuel consumption. While the neat soybean oil biodiesel was found to have the lowest fuel consumption rate, brake-specific fuel consumption, and CO and CO2 emissions, it had the highest exhaust gas temperature... [more]