Three-dimensional Structural Model Research Articles

Thermal storage performance of a horizontal eccentric distance spiral shell-tube heat storage tank

Considering the delayed thermal response rate exhibited by a horizontal spiral shell-tube heat storage tank during the heat storage process, we introduce an eccentric distance spiral shell-tube heat storage tank model to address the above-mentioned limitation and enhance overall performance. The numerical simulation is used to simulate the thermal loading behavior of the three-dimensional model structure with different eccentric distances throughout the melting process. The results demonstrate that an eccentric distance can effectively expedite the melting process of the PCM. When the eccentricity of the tank is raised from 0 mm to 20 mm, the amount of heat storage remains relatively constant throughout this range. However, the melting time experiences a notable reduction of 47.19 %. Additionally, the average heat storage rate significantly increases by 83.85 %. It is worth noting that further increasing the eccentricity to 30 mm doesn’t lead to significant optimization in the melting process. Subsequently, the influence of inlet temperature and flow rate on the thermal storage performance is investigated using a tank with an eccentricity of 20 mm as a reference unit. The results show that when the inlet temperature is increased from 343 K to 358 K and the flow rate is increased from 0.034 kg/s to 0.136 kg/s, the heat storage capacity is increased by 11.02 % and 2.21 %, the melting time is shortened by 46.21 % and 25.44 %, and the average heat storage rate is increased by 106.41 % and 37.07 %, respectively. However, it is essential to note that at an inlet temperature of 363 K, the thermal storage performance of the tank experiences a notable decline. The results of this research provide useful guidelines for enhancing the thermal storage efficiency of the horizontal spiral shell-tube heat storage tank.

Computational and experimental analysis of foxtail millet under salt stress and selenium supplementation.

Salinity stress is a major threat to crop growth and productivity. Millets are stress-tolerant crops that can withstand the environmental constraints. Foxtail millet is widely recognized as a drought and salinity-tolerant crop owing to its efficient ROS scavenging mechanism. Ascorbate peroxidase (APX) is one of the reactive oxygen species (ROS) scavenging enzymes that leads to hydrogen peroxide (H2O2) detoxification and stabilization of the internal biochemical state of the cell under stress. This inherent capacity of the APX enzyme can further be enhanced by the application of an external mitigant. This study focuses on the impact of salt (NaCl) and selenium (Se) application on the APX enzyme activity of foxtail millet using in silico and in-vitro techniques and mRNA expression studies. The NaCl was applied in the concentrations, i.e., 150mM and 200mM, while the Se was applied in 1μM, 5μM, and 10μM concentrations. The in silico studies involved three-dimensional structure modeling and molecular docking. The in vitro studies comprised the morphological and biochemical parameters, alongside mRNA expression studies in foxtail millet under NaCl stress and Se applications. The in silico studies revealed that the APX enzyme showed better interaction with Se as compared to NaCl, thus suggesting the enzyme-modulating role of Se. The morphological and biochemical analysis indicated that Se alleviated the NaCl (150mM and 200mM) and induced symptoms at 1µM as compared to 5 and 10µM by enhancing the morphological parameters, upregulating the gene expression and enzyme activity of APX, and ultimately reducing the H2O2 content significantly. The transcriptomic studies confirmed the upregulation of chloroplastic APX in response to salt stress and selenium supplementation. Hence, it can be concluded that Se as a mitigant at lower concentrations can alleviate NaCl stress in foxtail millet.

Numerical Study on the Flow and Structural Characteristics of a Large High Head Prototype Pump-Turbine under Different Operating Conditions

During the operation of pumped storage power stations, complex operating conditions can lead to different internal flow characteristics, which can cause different vibration characteristics or even damage to the structural components of the pump-turbine units. The time–frequency characteristics of the structural components’ response are of great significance for the safe operation of the unit. In this study, a three-dimensional flow field and structural field model of a large high head prototype pump-turbine is built in order to study the flow and the flow-induced dynamic response characteristics in different turbine operating conditions. The analyzed results show that the maximum deformation occurs at the inner head cover, and the maximum value of stress is located at the fillets on the outlet side of the stay vanes. Under the 50% load condition, the vortices in the runner caused by changes in the opening of the guide vanes result in the main response frequency of 4 fn of the stationary components. The research results can provide references for the structural optimization design of other pump-turbine units.

EasyModel: a user-friendly web-based interface based on MODELLER

Three-dimensional protein structures are invaluable sources of information for the functional annotation of protein molecules. Describing the function of a protein sequence is one of the most common problems in biology. Generally, this problem can be facilitated by studying the tertiary structure of proteins. In the lack of protein structures, comparative modeling often provides a useful three-dimensional model of the protein associated with at least one known protein structure. Comparative modeling predicts the tertiary structure of a certain protein sequence (target) mainly based on its homological sequence to the sequence of one or more proteins with known structures (templates). MODELLER is one of the most widely used tools for homology or comparative modeling of three-dimensional protein structures. However, most users find it challenging to start with MODELLER as it is a command line based and requires knowledge of basic Python scripting to use it efficiently. In this study, a web-based interface has been designed to predict the tertiary structure of proteins based on Modeller, which does the comparative modeling automatically, and uses PHP and Python programming languages. This tool is called “EasyModel” and is available at http://bioinf.modares.ac.ir/software/easymodel/. EasyModel provides a straightforward graphical interface for Modeller that can be used in only one browser.

Erosion Life Prediction of Metal Mesh Screen Pipes in Oil Wells Based on Numerical Simulation of Discrete Particle Flow.

High-speed fluid-carried sand particles pose a significant challenge to oil well screen pipes, leading to sand control failure and adversely affecting the well's production and recovery rates. This research targets the commonly used metal mesh screen pipe in oil well sand production and establishes a full-sized three-dimensional structure model. A fluid-solid coupling of discrete particle flow numerical simulation algorithm is incorporated to formulate a novel method for predicting the screen pipe's erosion life. This method provides a solution to the complex task of predicting the pipe's lifespan under oil sand fluid erosion. The analysis elucidates the impact of sand particles on the velocity distribution and erosion rate of the metal mesh at varying velocities, facilitating the prediction of the mesh screen pipe's erosion life. Key findings reveal that the velocity and erosion rate vary across the different layers. The first layer screen experiences velocity and erosion rates that are 3.6-3.76 times and 2.45-2.50 times, respectively, higher than those at the inlet. The second layer screen undergoes velocity and erosion rates 2.32-2.43 times and 1.04-1.06 times, respectively, higher than those at the inlet. Erosion failure primarily occurs in the first layer screen due to velocity expansion instigated by the screen tube's structure. The discrete flow numerical simulation method proves valuable in predicting the mesh screen's erosion life at different flow rates, with a maximum error of 6.38% when compared with field monitoring life values. This method introduces a new technical approach to predicting the life span of metal mesh screens in oil wells. The study concludes by suggesting measures to extend the screen pipe's lifespan, thereby enhancing oil recovery.

Identification of a functional peptide of a probiotic bacterium-derived protein for the sustained effect on preventing colitis

ABSTRACT Several probiotic-derived factors have been identified as effectors of probiotics for exerting beneficial effects on the host. However, there is a paucity of studies to elucidate mechanisms of their functions. p40, a secretory protein, is originally isolated from a probiotic bacterium, Lactobacillus rhamnosus GG. Thus, this study aimed to apply structure-functional analysis to define the functional peptide of p40 that modulates the epigenetic program in intestinal epithelial cells for sustained prevention of colitis. In silico analysis revealed that p40 is composed of a signal peptide (1–28 residues) followed by a coiled-coil domain with uncharacterized function on the N-terminus, a linker region, and a β-sheet domain with high homology to CHAP on the C-terminus. Based on the p40 three-dimensional structure model, two recombinant p40 peptides were generated, p40N120 (28–120 residues) and p40N180 (28–180 residues) that contain first two and first three coiled coils, respectively. Compared to full-length p40 (p40F) and p40N180, p40N120 showed similar or higher effects on up-regulating expression of Setd1b (encoding a methyltransferase), promoting mono- and trimethylation of histone 3 on lysine 4 (H3K4me1/3), and enhancing Tgfb gene expression and protein production that leads to SMAD2 phosphorylation in human colonoids and a mouse colonic epithelial cell line. Furthermore, supplementation with p40F and p40N120 in early life increased H3K4me1, Tgfb expression and differentiation of regulatory T cells (Tregs) in the colon, and mitigated disruption of epithelial barrier and inflammation induced by DSS in adult mice. This study reveals the structural feature of p40 and identifies a functional peptide of p40 that could maintain intestinal homeostasis.

Functional Characterization of 29 Cytochrome P450 4F2 Variants Identified in a Population of 8,380 Japanese Subjects and Assessment of Arachidonic Acid ω-Hydroxylation.

Cytochrome P450 4F2 (CYP4F2) is an enzyme that is involved in the metabolism of arachidonic acid (AA), vitamin E and K (VK), and xenobiotics including drugs. CYP4F2*3 polymorphism (rs2108622; c.1297G>A; p.Val433Met) has been associated with hypertension, ischemic stroke, and variation in the effectiveness of the anticoagulant drug warfarin. In this study, we characterized wild-type CYP4F2 and 28 CYP4F2 variants, including a Val433Met substitution, detected in 8,380 Japanese subjects. The CYP4F2 variants were heterologously expressed in 293FT cells to measure the concentrations of CYP4F2 variant holoenzymes using carbon monoxide-reduced difference spectroscopy, where the wild type and 18 holoenzyme variants showed a peak at 450 nm. Kinetic parameters (Vmax , S50 , and CL int as Vmax /S50 ) of AA ω-hydroxylation were determined for the wild type and 21 variants with enzyme activity. Compared to the wild type, two variants showed significantly decreased CL int values for AA ω-hydroxylation. The values for seven variants could not be determined because no enzymatic activity was detected at the highest substrate concentration used. Three-dimensional structural modeling was performed to determine the reason for reduced enzymatic activity of the CYP4F2 variants. Our findings contribute to a better understanding of CYP4F2 variant-associated diseases and possible future therapeutic strategies. Significance Statement CYP4F2 is involved in the metabolism of AA and VK, and CYP4F2*3 polymorphisms have been associated with hypertension and variation in the effectiveness of the anticoagulant drug warfarin. In this study, we present a functional analysis of 28 CYP4F2 variants identified in Japanese subjects, demonstrating that seven gene polymorphisms cause loss of CYP4F2 function, and propose structural changes that lead to altered function.

Effects of Aftershocks on the Seismic Performances of Reinforced Concrete Eccentric Frame Structures

Strong aftershocks have the potential to cause accumulated damage in structures, a feature which has been reported in post-earthquake reconnaissance studies, particularly for eccentric or irregular structures. This study aims to investigate the seismic behaviors of eccentric RC structural models under mainshock–aftershock (MSAS) sequences. In this study, three-dimensional structural models with eccentricities of 5%, 10%, 15%, 20%, 25%, and 30%, and an eccentricity of 0 (symmetric structural model) are developed by changing the positions of the centers of the structural mass. A static pushover analysis and a nonlinear time history analysis are conducted on the structural models with different eccentricities considering unidirectional and bidirectional earthquake loading (including mainshock ground motion and MSAS sequences). The amplitude of the aftershock ground motion is scaled according to the structural damage levels calibrated with the inter-story drift ratio (IDR). Furthermore, the differences in seismic responses between the unidirectional and bidirectional eccentric structures are discussed. The results show that the peak displacements of the unidirectional eccentric structures under MSAS sequences are nearly 1.4 times higher than those under mainshock ground motions. The structural seismic responses under unidirectional earthquake loading are more sensitive to the intensity of aftershock ground motions than those under bidirectional earthquake loading. Compared with unidirectional eccentric structures, bidirectional eccentric structures are more sensitive to the intensity of aftershock ground motions and have larger torsional angles and more complex displacement trends. The maximum displacement and the maximum IDR of bidirectional eccentric structures under MSAS sequences can reach 1.5 times and 1.4 times of those under mainshock ground motions, respectively.

Analysis of Properties of the Multilayer Meander Structures for Wireless Communications

Multilayer meander structures for wireless communications are presented in this paper. The miniaturization of meander structures is solved by positioning the meander conductor in multiple layers. The influence of the increasing number of layers and connecting vias on the operational parameters of the meander structures is investigated. Three-dimensional models of the meander structures are designed and analyzed in the CST Microwave Studio© software package. The general mathematical model of the meander structure is presented. The computer-based simulation is verified by a physical experiment and analytical calculations. The investigation shows that it is possible to miniaturize the meander structure by placing it into different layers and connecting the meander conductors with vias. The overall length of the meander structure is decreased by 48% from 16.24 mm to 8.4 mm, while the delay time td is changed only by less than 3.2% and increased till 1.145 ns, which is 35 ps. The overall dimensions of the miniaturized meander structure are 8.4 × 17.35 × 0.76 mm. The designed structure is suitable for operation at a 2.4–2.5 GHz ISM frequency band.

Structural analysis of cylindrical composite structures for high velocity applications: A parametric optimization study

This research explores the significance of structural modifications on the energy absorption and ballistic response of a cylindrical composite structure exposed to high velocity impact. The composite structure comprises an aramid honeycomb core supported by cylindrically shaped aluminum facesheets on both sides. Ballistic impact tests were performed by firing cylindrical projectiles, namely conical and hemispherical, using a pneumatic gun. Three-dimensional models of the composite structure with aluminum facesheets and an aramid honeycomb core were created using ABAQUS/Explicit. By utilizing numerical models, impact phenomena such as facesheet failure, core crushing, facesheet debonding, etc. were analyzed, which showed a high degree of similarity with a real impact scenario, thus validating the model. Furthermore, a parametric analysis was carried out using this model on different parameters affecting the composite structure. The study also examined the effect of these parameters on the ballistic responses of the cylindrical composite structure against both projectiles using a grey-based Taguchi analysis method. The investigation focused on multi-response optimization of the cylindrical composite structure's characteristics using Minitab software. The proposed grey-based Taguchi method proved effective in solving multi-response problems.

Mexican argemone (Argemone mexicana L.) CYP719A14 protein bioinformatic analysis

CYP719A14 structure analysis and its interaction with ligands via bioinformatic methods. Methods. Homologous modeling of three-dimensional structure of enzyme. Molecular docking. Results. CYP719A14 enzyme, which shows cheilanthifoline synthase activity, model was build based on results of homologous modeling. Interaction of built model with possible substrates – benzylisoquinoline compounds: (S)-Scoulerine, (S)-Cheilanthifoline, (S)-Tetrahydrocolumbamine, (S)-Reticuline was investigated using molecular docking method, thermodynamic characteristics of interaction were calculated. Potential Ligand Access Chanel – potential active center was identified. Conclusions. Potential Ligand Access Chanel CYP719A14 enzyme, which is formed by aminoacids residues PHE57-GLY69, ALA285-ARG310, THR369-HSD390 researched, allowing to use discovered data in alkaloid engineering research with aim to improve Mexican argemone alkaloid profile.

Design of a Multi-epitope Vaccine against Covid-19: An In silico Approach

Background: The control of the Covid-19 epidemic depends on designing a novel, effec-tive vaccine against it. Currently, available vaccines cannot provide complete protection against various mutants of Covid-19. Objective: The present investigation aimed to design a new multi-epitope vaccine by using in silico tools. Methods: In the present study, the spike-glycoprotein was targeted, desirably stimulating both B and T-cell lymphocytes, providing effective and safe responses in the host immune system. The de-sired vaccine has been found to possess 448 amino acids of spike glycoprotein. The prognosticated epitopes included 10 CTL, 4 linear B-cells, and 14 HTL, including the 128 amino acid sequence of 50S ribosomal protein adjuvant joined by GPGPG and AAY linkers on the N terminus of linear B-cell, HTL, and CTL epitopes, and the C-terminal joined with HHHHHH (6HIS) linker, indicating stability for vaccine structure. Results: The molecular docking has revealed the protein-protein restricting communication between the immunization construct and the TLR-3-resistant receptor. The vaccine has been developed through selected epitopes, an adjuvant, and an additional epitope. Docking assays with toll-like re-ceptor 3 have been run on a three-dimensional structural model of the vaccine to gauge its immuno-logical potency. Our findings support the hypothesis that our vaccination will activate TLR-mediated downstream immune pathways by aggressively interacting with the innate receptor. Conclusion: The results suggest that the proposed chimeric peptide could initiate an efficient and safe immune response against Covid-19. The proposed vaccine has been proven safe in all critical parameters.

Modeling Side Chains in the Three-Dimensional Structure of Proteins for Post-Translational Modifications.

Amino acid substitutions and post-translational modifications (PTMs) play a crucial role in many cellular processes by directly affecting the structural and dynamic features of protein interaction. Despite their importance, the understanding of protein PTMs at the structural level is still largely incomplete. The Protein Data Bank contains a relatively small number of 3D structures having post-translational modifications. Although recent years have witnessed significant progress in three-dimensional modeling (3D) of proteins using neural networks, the problem related to predicting accurate PTMs in proteins has been largely ignored. Predicting accurate 3D PTM models in proteins is closely related to another fundamental problem: predicting the correct side-chain conformations of amino acid residues in proteins. An analysis of publications as well as the paid and free software packages for modeling three-dimensional structures showed that most of them focus on working with unmodified proteins and canonical amino acid residues; the number of articles and software packages placing emphasis on modeling three-dimensional PTM structures is an order of magnitude smaller. This paper focuses on modeling the side-chain conformations of proteins containing PTMs (nonstandard amino acid residues). We collected our own libraries comprising the most frequently observed PTMs from the PDB and implemented a number of algorithms for predicting the side-chain conformation at modification points and in the immediate environment of the protein. A comprehensive analysis of both the algorithms per se and compared to the common Rosetta and FoldX structure modeling packages was also carried out. The proposed algorithmic solutions are comparable in their characteristics to the well-known Rosetta and FoldX packages for the modeling of three-dimensional structures and have great potential for further development and optimization. The source code of algorithmic solutions has been deposited to and is available at the GitHub source.

Quality evaluation index development for nutritional management in patients with nasopharyngeal carcinoma during peri-radiotherapy

ObjectivesIt is necessary to construct an evaluation index for patients with nasopharyngeal carcinoma during peri-radiotherapy to provide a reference for the evaluation of the quality of nutritional management of patients with nasopharyngeal carcinoma during peri-radiotherapy. The aim of this study was to construct a set of scientific, comprehensive, and feasible indicators for evaluating the quality of nutrition management in patients with nasopharyngeal carcinoma during peri-radiotherapy to provide a unified reference basis for objective nutritional evaluation of these patients during the peri-radiotherapy period and to provide insights to the clinical treatment and care of these patients. MethodsA multidisciplinary research team was set up from December 2021 to April 2022. We took the three-dimensional quality structure model as the theoretical framework; based on the literature review, the first draft of the nutrition management quality evaluation index for patients with nasopharyngeal carcinoma during peri-radiotherapy was formed by a semi-structured interview. The Delphi correspondence method was used to survey 18 experts from 12 cities in China. The multidimensional analytical hierarchy process was used to determine the evaluation index and weight of nutrition management quality of patients with nasopharyngeal carcinoma during peri-radiotherapy. ResultsThe effective questionnaire recovery rates of the two rounds of letters were 90.005% and 100%, respectively, and the expert authority coefficients were 0.906 and 0.918, respectively. The Kendall harmony coefficients of the two rounds of letters were 0.271 to 0.313 and 0.309 to 0.349, respectively. The nutrition management quality evaluation index of patients with nasopharyngeal carcinoma during peri-radiotherapy was constructed and included 3 first-level indexes, 10 second-level indexes, and 71 third-level indexes. ConclusionThe evaluation index of the nutrition management quality of patients with nasopharyngeal carcinoma during peri-radiotherapy is scientific and reliable, and it may have a certain guiding significance for nurses to evaluate the quality of nutrition management of these patients during this period.

Computationally-driven epitope identification of PEDV N-protein and its application in development of immunoassay for PEDV detection

The nucleocapsid (N) protein is a suitable candidate for early diagnosis of porcine epidemic diarrhea virus (PEDV). Here, we identified the linear B-cell epitopes of the PEDV N-protein by integrating a computational-experimental framework and constructed three-dimensional (3D) structure model of the N protein using the ColabFold program in Google Colaboratory. Furthermore, we prepared the monoclonal antibodies against the predicted epitopes and recombinant N protein, respectively, and selected pairing mAbs (named 9C4 and 3C5) to develop a double-antibody sandwich immunochromatographic test strip using CdSe/ZnS quantum dots (QDs)-labelled 9C4 and 3C5 as capture and detection antibodies, respectively. This strip can specifically detect PEDV within 10 min with a detection limit of less than 6.25 × 103 TCID50/mL. In comparison with RT-PCR for testing 90 clinical samples, the relative sensitivity and specificity of the strip were found to be 98.0% and 100%, respectively, with a concordance rate of 98.9% and a kappa value of 0.978, indicating that QDs-ICTS is a reliable method for the application of PEDV detection in clinical samples.

Crystallization-driven evolution of water occurrence states with implications on dewaterability improvement of waste-activated sludge

This study proposed to improve the dewaterability of waste-activated sludge (WAS) through crystallization-driven evolution of water occurrence states. Primarily, the feasibility of clathrate hydrate (i.e., CO2 hydrate) formation in WAS was examined. The thermodynamic analysis indicated that the CO2 hydrate formation with the excessive water in WAS followed pseudo-first-order kinetics, and fit of the data yielded a kobs value of 3.905 × 10−5 L∙mol−1∙s−1 for 274.15 K. With the water conversion efficiency of 100%, the crystallization-dissociation process of CO2 hydrate significantly improved the dewaterability of WAS in term of capillary suction time (CST) decreasing from 251.5 s to 57.4 s. Also, the relief of gas pressure can induce the hydrate dissociation, which creates a novel way to recycle CO2 gas and save the consumption of chemicals required by sludge dewatering process. Regarding the mechanism of hydrates-based sludge dewatering, the evolution of water occurrence state was investigated. The in-situ synchrotron X-ray computed microtomography visually analyzed the micro-scale porosity and interstitial water of WAS flocs. The model of three-dimensional pore structure was established and the porosity parameters of solid aggregates were determined. It was found that the volume of connected pores and the total pore volume fraction of solid compositions increased. But the mean volume and mean area of isolated pores simultaneously decreased by 14.6% and 12.4%, respectively, which meant that the steric hindrance caused by isolated pores was weakened due to the reduced solid-water contact area. In addition, the crystallization of water caused the reformation of conformation arrangement of vicinal water and solid molecules, which highly organized the water molecules into the crystal structure. Accordingly, an estimation method for vicinal water layer thickness was developed based on atom force microscope. The thickness of vicinal water layer was found to be reduced by 77.4% and the hydration repulsion among solid compositions was correspondingly weakened, which facilitated the aggregation of solid compositions, and the relatively separated hydrate phase and solid phase could be formed. All the above results open up a novel strategy for enhanced water-solid separation of WAS through the crystallization-driven evolution of water occurrence states. As distinguished from the conventional approaches, the hydrates-based sludge dewatering enhances the water-solid separation only with regulating the spatial arrangement of water-solid molecules, but without altering the chemical compositions. Thus, more chances can be created to increase the environmentally friendly attributes related to WAS dewatering.

Deep learning-enabled 3D multimodal fusion of cone-beam CT and intraoral mesh scans for clinically applicable tooth-bone reconstruction

High-fidelity three-dimensional (3D) models of tooth-bone structures are valuable for virtual dental treatment planning; however, they require integrating data from cone-beam computed tomography (CBCT) and intraoral scans (IOS) using methods that are either error-prone or time-consuming. Hence, this study presents Deep Dental Multimodal Fusion (DDMF), an automatic multimodal framework that reconstructs 3D tooth-bone structures using CBCT and IOS. Specifically, the DDMF framework comprises CBCT and IOS segmentation modules as well as a multimodal reconstruction module with novel pixel representation learning architectures, prior knowledge-guided losses, and geometry-based 3D fusion techniques. Experiments on real-world large-scale datasets revealed that DDMF achieved superior segmentation performance on CBCT and IOS, achieving a 0.17mm average symmetric surface distance (ASSD) for 3D fusion with a substantial processing time reduction. Additionally, clinical applicability studies have demonstrated DDMF's potential for accurately simulating tooth-bone structures throughout the orthodontic treatment process.

Lithofacies influence characteristics on typical shale pore structure

Clarifying the three-dimensional pore throat structure characteristics of shale is the foundation for efficient development of shale oil and gas. In this paper, firstly, by using FIB-SEM high-tech characterization technology, three-dimensional quantitative characterization of shale pore-throat structures under different lithological conditions was carried out. Secondly, reconstruct through binary images to establish a three-dimensional pore-throat structure model. Thirdly, the coupling mechanism of “pore distribution, form factor, coordination number, throat diameter” is quantitatively clarified. Results show that: (a). For six shale samples, the volume fraction is mostly concentrated in the range of pore diameter greater than 20 nm and less than 300 nm. When the pore diameter is greater than 300 nm, the proportion of volume fraction is lower. (b). For six shale samples, the pore quantity distribution is mostly concentrated in the range of pore shape factor greater than 0.04 and less than 0.07. When the pore diameter is less than 0.04 or greater than 0.07, the pore quantity distribution is lower. (c). For six shale samples, the pore volume distribution is mostly concentrated in the range of coordination number greater than 1 and less than 4. When the pore diameter is less than 1 or greater than 4, the pore volume distribution is lower. (d). For six shale samples, the throat volume distribution is mostly concentrated in the range of throat diameter greater than 8 nm and less than 120 nm. When the throat diameter is less than 8 nm or greater than 120 nm, the throat volume distribution is lower. The pore structure of shale is very complex, mainly manifested by a variety of pore types.

A new design for thermophotovoltaic cell thermal management under high-flux irradiation

Efficient thermal management plays a significant role in a thermophotovoltaic system, especially in exploring the energy conversion characteristics of thermophotovoltaic cells (TPVC). If the cooling effect is insufficient, it is easy to cause temperature differences along the thickness direction of the cell. Meanwhile, temperature non-uniformity will cause electrical mismatch loss and reduce the reliability of cells. Therefore, a new design of a double-sided asymmetric cooling arrangement for testing the energy conversion performance of the TPVC at high-flux irradiation is proposed. This design consisted of a multi-channel water-cooling structure at the back (lower surface) of the TPVC, and the nitrogen is used to cool the TPVC radiation surface (upper surface). A three-dimensional structural computational model was created to examine the potential of the new design to lower cell temperature. According to the simulation results, compared with the conventional method, when the temperature of the radiation source is 2000 K, 2500 K, and 3000 K, the energy conversion efficiency has been improved by 7.23%, 17.97%, and 24.12%, respectively. Double-side cooling has a 30% higher uniformity at high-flux incident radiation than single-side cooling. Therefore, this new design model not only reduces the temperature difference between the upper and lower surfaces but also increases the temperature uniformity.

Three-dimensional electrical structure model of the Yangbajain geothermal field in Tibet: Evidence obtained from magnetotelluric data

Three-dimensional electrical structure model of the Yangbajain geothermal field in Tibet: Evidence obtained from magnetotelluric data