Establishing a suitable classification and evaluation scheme is crucial for sweet spot prediction and efficient development of shale oil in the Chang 71-2 sub-member of the Longdong area. In this paper, a series of experiments, such as casting thin sections (CTS), scanning electron microscopy (SEM), low-temperature nitrogen adsorption (LTNA), high-pressure mercury intrusion porosimetry (HMIP), and nuclear magnetic resonance (NMR), were integrated to classify the pore throats and shale oil reservoirs in the study area. Moreover, the pore structure characteristics of different types of reservoirs and their contributions to productivity were revealed. The results show that the pore-throat system can be divided into four parts: large pore throats (>0.2 μm), medium pore throats (0.08~0.2 μm), small pore throats (0.03~0.08 μm), and micropore throats ( 0.1 mD), type II (Φ ≥ 8%, 0.05 mD < K < 0.1 mD), type III (Φ ≥ 5%, 0.02 mD < K < 0.05 mD) and type IV (Φ < 5% or K < 0.02 mD... [more]

Channel wing is a propeller-coupling layout that has good low-speed performance and S/VTOL potential. Focused on the application of this layout at the S/VTOL stage, this paper attempts to find the interaction mechanism for the distributed propeller channel wing. Firstly, the computation method based on RANS equations for propeller−wing integration was established with Momentum Source Method, which was compared with the unsteady Sliding Mesh method and validated by a ducted propeller. Secondly, the performances and aerodynamic characteristics of the single-propeller channel wings with two different airfoils were analyzed, and a ground test for the scaled model was conducted. Finally, a four-propeller channel wing was analyzed and compared with single-propeller channel wing, then the flow field characteristics were discussed in depth. The study shows that the airfoil shape will strongly affect the lift of channel wing at S/VTOL stage. Multi-propeller channel wing analysis indicates that... [more]

Recognizing the challenges that today’s hydroponics industry and tomorrow’s plant factories are and will be dealing with requires some strategic thinking [...]

Natural disasters have great destructive power and can potentially wipe out great lengths of power lines. A resilient grid can recover from adverse conditions and restore service quickly. Therefore, the present work proposes a novel methodology to reconfigure power grids through graph theory after an extreme event. The least-cost solution through a minimum spanning tree (MST) with a radial topology that connects all grid users is identified. To this end, the authors have developed an iterative minimum-path heuristic algorithm. The optimal location of transformers and maintenance holes in the grid is obtained with the modified Prim algorithm, and the Greedy algorithm complements the process. The span distance and capacity restrictions define the transformer’s number, where larger spans and capacities reduce the number of components in the grid. The performance of the procedure has been tested in the urban zone Quito Tenis of Ecuador, and the algorithm proved to be scalable. Grid reconfi... [more]

To improve the detection speed for wide-frequency dense signals (WFDSs), a fast minimization algorithm (FMA) was proposed in this study. Firstly, this study modeled the WFDSs and performed a Taylor-series expansion of the sampled model. Secondly, we simplified the sampling model based on the augmented Lagrange multiplier (ALM) method and then calculated the augmented Lagrange function of the sampling model. Finally, according to the alternating minimization strategy, the Lagrange multiplier vector and the sparse block phasor in the function were iterated individually to realize the measurement of the original signal components. The results show that the algorithm improved the analysis accuracy of the WFDS by 35% to 46% on the IEEE C37.118.1a-2014 standard for the wide-frequency noise test, harmonic modulation test, and step-change test, providing a theoretical basis for the development of the P-class phasor measurement unit (PMU).

The advancements in intelligent systems have contributed tremendously to the fields of bioinformatics, health, and medicine. Intelligent classification and prediction techniques have been used in studying microarray datasets, which store information about the ways used to express the genes, to assist greatly in diagnosing chronic diseases, such as cancer in its earlier stage, which is important and challenging. However, the high-dimensionality and noisy nature of the microarray data lead to slow performance and low cancer classification accuracy while using machine learning techniques. In this paper, a hybrid filter-genetic feature selection approach has been proposed to solve the high-dimensional microarray datasets problem which ultimately enhances the performance of cancer classification precision. First, the filter feature selection methods including information gain, information gain ratio, and Chi-squared are applied in this study to select the most significant features of cancer... [more]

The transmission in automobiles is the core component to ensure operational stability. Heat accumulation in the meshing process will reduce the transmission efficiency and affect the service life. Here, the essential physical process to improve transmission heat dissipation is the dynamic evolution process and the thermal transfer characteristics of lubricating oil fields during gear meshing. This paper presents a modeling and solving method for gear meshing lubrication and thermal transfer features based on the volume of the fluid model and piecewise linear interface construction (VOF-PLIC). The dynamic mesh technique combines spring smoothing and reconstruction to optimize the numerical solution process. The dynamic evolution law of gear meshing lubrication and thermal transfer is obtained by analyzing the lubrication evolution process under different speed/steering conditions. The results show that the proposed modeling and solving method could well reveal the lubrication and therma... [more]

In the process of metal cutting, a large amount of chips that are difficult to reuse will be produced, resulting in resource waste. As a novel metal forming process, cryogenic-temperature extrusion machining (CT-EM) can directly process chips into usable fins with a surface micro-groove structure, which has the advantage of high efficiency, energy saving and flexibility. In this study, the effects of four parameters (compression ratio λ, rake angle of the tool α, friction coefficient μ and the constraining tool corner radius R) on the effective stress, temperature and formability of micro-groove fins produced by CT-EM and room-temperature extrusion machining (RT-EM) are investigated. The results show that the maximum effective stress and formability of CT-EM are larger than that of RT-EM, which indicates that CT-EM has greater advantages in the preparation of micro-groove fins. At a λ of 0.7, the formability of CT-EM is the best. Reducing the λ and α, or increasing the μ, can improve t... [more]

Conventionally, fused deposition modeling (FDM) 3D printing allows for multiple color printing, but it is limited to only various monochromatic colors. Consequently, the effect of progressive color transition cannot be reflected. To produce the progressive 3-D color printing effect, the only solution is to implement stereolithography technology, which is particularly expensive. Therefore, the aim of this paper is to develop a color mixing mechanism to be incorporated into an FDM 3D printer, which is relatively inexpensive. The underlying idea is to pre-mix the color so that the FDM 3D printer can produce a progressive color printing effect. Three conceptual color mixing mechanisms are designed, i.e., a triangular stirring shaft, a rectangular spoiler stirring shaft, and a spiral blade stirring shaft. The mixing process is modeled based on the non-Newtonian fluid theory, in which the Carreau model is used to simulate the motion of pseudoplastic fluids in FDM 3D printing under forced mix... [more]

The entire industry is changing as a result of new developments in digital technology, and maintenance management is a crucial procedure that may take advantage of the opportunities brought about by industrial digitalization. To support digital innovation in maintenance management, this study intends to meet the cutting-edge necessity of addressing a transformation strategy in industrial contexts. Setting up a customized pathway with adequate methodologies, digitalization tools, and collaboration between the several stakeholders involved in the maintenance environment is the first step in this process. The results of a previous conference contribution, which revealed important digitalization variables in maintenance management, served as the foundation for the research approach herein suggested. We lead a thorough assessment of the literature to categorize the potential benefits and challenges in maintenance digitalization to be assessed in conjunction with the important digitalization... [more]

Pipeline is one of the safest and most cost-effective means of transportation for hydrocarbons. However, hydrocarbon releases and the subsequent fires and explosions, are presented as persistent events. Quantitative Risk Assessment (QRA) enables one to address the risk and to prevent these events. In this regard, different approaches have been proposed for pipelines, but few studies are focused on oil transportation. This paper presents a methodology for performing QRA for onshore oil pipelines, which is based on the calculation of individual and societal risk indicators. This methodology is illustrated using an authentic case study of a segment of 17.53 km of the length of an onshore oil pipeline located in the southwest of Colombia, considering jet and pool fire scenarios. The results show that the Individual Risk Per Annum (IRPA) for operation (and maintenance) and administrative workers are 6.14 × 10−4 and 8.52 × 10−5 yr−1, respectively. The IRPA for people close to the pipeline is... [more]

The data distribution of the vibration signal under different speed conditions of the gearbox is different, which leads to reduced accuracy of fault diagnosis. In this regard, this paper proposes a deep transfer fault diagnosis algorithm combining adaptive multi-threshold segmentation and subdomain adaptation. First of all, in the data acquisition stage, a non-contact, easy-to-arrange, and low-cost sound pressure sensor is used to collect equipment signals, which effectively solves the problems of contact installation limitations and increasingly strict layout requirements faced by traditional vibration signal-based methods. The continuous wavelet transform (CWT) is then used to convert the original vibration signal of the device into time−frequency image samples. Further, to highlight the target fault characteristics of the samples, the gray wolf optimization algorithm (GWO) is combined with symmetric cross entropy (SCE) to perform adaptive multi-threshold segmentation on the image sa... [more]

In this paper, by analyzing the heat and mass transfer characteristics of the dehumidification runner microelement channel of a drinking water emergency extraction vehicle, a mathematical model of heat and mass transfer in the water intake process is established, and the influence of the runner parameters (adsorbent thickness, regeneration angle, rotation speed) and air parameters (treatment air temperature/humidity, regenerated air temperature/humidity) on the water intake characteristics is mainly studied. Water extraction experiments are carried out in arid desert areas and humid island environments. The test results showed that compared with the calculated data, the deviations in the temperature and humidity of the treated air outlet were 3.03% and 4.14%, respectively, and the deviation value of the water intake was 8.23% when the moisture content of the inlet air was 2 g/kg.

Even in the context of smart mines, unsafe human acts are still an important cause of coal mine gas explosion accidents, but there are few models to analyze unsafe human acts in coal mine gas explosion accidents. This study tries to solve this problem through a risk assessment method of unsafe acts in coal mine gas explosion accidents based on Human Factor Analysis and Classification system (HFACS-GE) and Bayesian networks (BN). After verifying the reliability of HFACS-GE framework, a BN model of risk factors of unsafe acts was established with the Chi-square test and odds ratios analysis. After reasoning analysis, risk paths and key risk factors of unsafe acts were obtained, and preventive measures were granted. Based on the analysis of 100 coal mine gas explosion cases, the maximum probability of five kinds of unsafe acts of employees is 38%. Among the 22 risk factors, the mental state of employees has the greatest influence on the habitual violation of regulations, and the sensitivi... [more]

Liquid−liquid extraction has proven to be an aid in biologics manufacturing for cell and component separation. Because distribution coefficients and separation factors can be appropriately adjusted via phase screening, especially in aqueous two-phase systems, one stage is frequently feasible. For biologics separation, aqueous two-phase systems have proven to be feasible and efficient. The simple mixer−settler equipment type is still not standard in biologics manufacturing operations. Therefore, a scalable digital twin would be of aid for operator training, process design under the regulatory demanded quality by design approach for risk analysis, design and control space definition, and predictive maintenance. Autonomous operation is achieved with the aid of process analytical technology to update the digital twin to real time events and to allow process control near any optimal operation point. Autonomous operation is first demonstrated with an experimental feasibility study based on a... [more]

At present, there has been no mechanized equipment designed for the separation of the leaves from the stems of wakame in China, and the stem−leaf separation is mainly completed by manual work, which suffers from problems such as low efficiency, high cost, and poor quality. To develop mechanized stem−leaf separation equipment of wakame, it is necessary to have a preliminary understanding of the biomechanical characteristics of wakame. In this study, we adopted an electronic universal testing machine, a texture tester, and a friction tester to investigate the mechanical characteristics of the stems and leaves of salted wakame. Analysis was performed to clarify the effects of salted wakame thickness and loading speed on the tension, compression, shear, and separation mechanical properties as well as the effects of the loading speed, normal force, and contact material on the friction characteristics. As shown in the results, the average tensile strength, shear strength, and resilience of s... [more]

The intelligent development of coal mines is a crucial way to achieve the safe, efficient, green, and low-carbon transformation of the coal industry and to reach the “double carbon” target, which is related to the life and health of miners, the stable development of enterprises and the national energy reform. As directly affected subjects, the cooperative attitudes of miners in different emotional states have a significant impact on the smooth implementation of intelligent coal mine renovation projects. Hence, we combined the RDEU theory and game theory, constructed a three-party evolutionary game model of the small and medium-sized energy enterprises (SMEE), the government, and the miner, considered the influence of the strategies made by the miner on the equilibrium strategy choices of other game subjects in the intelligent coal mine construction under the rational and irrational emotional states of the miner, and finally used MATLAB 2021 to simulate and analyze the impact of the evo... [more]

This research is motivated by the practical pre-steelmaking stage in large iron and steel companies, which have steady and heavy demands for the steelmaking production process. Our problem studied the pre-steelmaking stage, which consists of two steps that are needed in each convertor before the steelmaking process. During each step, a necessary transportation must be operated by a crane. In contrast to the classical two-machine flowshop problem during which both machines are fixed, these transporting operations are performed by two mounted, removeable cranes. Our problem is scheduling two-crane operations for the sake of minimizing the last convertors’ completion time (makespan); that is, the last finish time among the total operation of the two cranes is minimized. This study was concerned with resolving the interference between two cranes by determining the sequence of loading operations and how each crane avoids the other in order to let it complete its next operation first. A mixe... [more]

For a wind energy system, main speed-increasing gearboxes, pitch drives and yaw drives are composed of a multistage planetary gear system. However, inevitable errors in the manufacturing and assembling of the gears lead to uneven load of distribution in the planetary gear system; thus, its service life and reliability decrease greatly, which would eventually affect the normal operation of the whole wind power system. In this study, a dynamic load sharing model of pitch drive is established with a lumped-parameter method. Given the manufacturing and assembly errors and central floating gear, the dynamic equations for each component, the stiffness matrix and damping matrix, the dynamic load sharing coefficient and the floating displacement of the sun gear are obtained according to the dynamic meshing force and damping load. Furthermore, the load sharing coefficient for external and internal meshing of the pitch drive for a 2 MW wind turbine with a three-stage planetary gear are achieved.... [more]

Inflammation is a complex response of the human organism and relates to the onset of various disorders including diabetes. The current research work aimed at investigating the anti-inflammatory and anti-diabetic effects of ferruginan, a compound isolated from Olea ferruginea. Its in vitro anti-inflammatory activity was determined by using the heat-induced hemolysis assay, while the anti-diabetic effect of the compound was studied by the yeast cell glucose uptake assay. Ferruginan exhibited a maximum of 71.82% inhibition of inflammation and also increased the uptake of glucose by yeast cells by up to 74.96% at the highest tested concentration (100 µM). Moreover, ferruginan inhibited α-amylase dose-dependently, by up to 75.45% at the same concentration. These results indicated that ferruginan possesses promising anti-inflammatory and anti-diabetic properties in vitro, even if at high concentrations. To provide preliminary hypotheses on the potentially multi-target mechanisms underlying s... [more]

The sulfide stress cracking (SSC) behavior of three micro-alloying 110 ksi grade Cr-Mo casing steels were evaluated according to the A-Method tensile test specified in the NACE TM0177 standard (NACE A-method). The fractures of SSC specimens and the micro-structures of the casing steels were characterized by scanning electron microscopy (SEM) with electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM) in the BF and STEM mode. The results show that on the premise of 110 ksi, the yield strength of Co-Mo steel was satisfactory, finer spherical carbides increased the number of irreversible traps; widened polygonised martensitic laths, lowered dislocation density, and lowered the proportion of high-angle grain boundaries and the Σ3 boundaries decreased hydrogen permeability and diffusivity. The SSC resistance of Co-Mo steel with above micro structure characteristics was enhanced.

Automated crack detection technologies based on deep learning have been extensively used as one of the indicators of performance degradation of concrete structures. However, there are numerous drawbacks of existing methods in crack segmentation due to the fine and microscopic properties of cracks. Aiming to address this issue, a crack segmentation method is proposed. First, a pyramidal residual network based on encoder−decoder using Omni-Dimensional Dynamic Convolution is suggested to explore the network suitable for the task of crack segmentation. Additionally, the proposed method uses the mean intersection over union as the network evaluation index to lessen the impact of background features on the network performance in the evaluation and adopts a multi-loss calculation of positive and negative sample imbalance to weigh the negative impact of sample imbalance. As a final step in performance evaluation, a dataset for concrete cracks is developed. By using our dataset, the proposed me... [more]

In this study, the effects of oven dehydration on chemical and bioactive properties, fatty acids, polyphenolic compounds and minerals of sandal strawberry tree fruit were investigated. While total carotenoid contents of the sandal strawberry tree fruit are determined between 4.20 (120 °C) and 5.43 µg/g (70 °C), tannin amounts of the sandal strawberry tree fruit were recorded between 5.13 (control) and 6.37% (70 and 120 °C). While total phenolic contents of dehydrated sandal strawberry tree fruit were found between 444.16 (120 °C) and 665.13 mgGAE/100 g (control), total flavonoid amounts of dehydrated sandal strawberry tree fruit were recorded between 592.91 (control) and 788.71 mg/100 g (120 °C). Antioxidant activity values of fruit ranged from 4.10 (120 °C) to 7.30 mmol TE/kg (control). Both total phenolic amounts and antioxidant activity values of untreated (control) sandal strawberry tree fruit were found to be higher than dehydrated ones, and a linear relationship was determined be... [more]

There is a significant potential to increase the sustainability of the fishing and aquaculture industries through the maximization of the processing of byproducts. Enzymatic hydrolysis provides an opportunity to valorize downstream fish industry byproducts for the production of protein hydrolysates (FPH) as a source of bioactive peptides (BAP) with health benefits. Deteriorative oxidative reactions may occur during the enzymatic hydrolysis of byproducts, influencing the safety or bioactivities of the end product. Lipid oxidation, autolysis mediated by endogenous enzymes in viscera, protein degradation, and formation of low-molecular-weight metabolites are the main reactions that are expected to occur during hydrolysis and need to be controlled. These depend on the freshness, proper handling, and the type of byproducts used. Viscera, frames, trimmings, and heads are the byproducts most available for enzymatic hydrolysis. They differ in their composition, and, thus, require standardizati... [more]

This paper investigates the risk quantification for Unmanned Aircraft (UA) in urban environments, focusing on the safety of ground people. An assessment methodology is proposed to quantify the flying risk, which indicates the ground fatalities resulted from different potential risk sources. With the knowledge of UA’s specifications and ground environments, the flying risk of the target UA flying in the target area could be evaluated from the combination of results from independent assessment procedures focusing on multiple potential risk sources with specific safety metrics. A study case to assess the flying risk of the Talon and the DJI Inspire 2 flying in one piece of the region in Chengdu is presented. From the assessment result, the airspace management strategies for both Talon and DJI Inspires 2 could be easily developed to guarantee the safety of ground people, therefore, this risk quantification method could be a general tool to support decision-making in safety work.