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The non-Fourier heat transfer model has gained significant attention in practical engineering applications, particularly under extreme conditions. However, solving the three-dimensional non-Fourier hyperbolic heat conduction equation remains a challenge. A method for solving the three-dimensional Maxwell-Cattaneo-Vernotte hyperbolic heat conduction equation on unstructured grids is proposed, where the total diffusion term is divided into normal diffusion term and cross diffusion term, and the temperature gradient is solved by reconstruction gradient. The convergence and accuracy of this method are verified by calculating the heat transfer process of a three-dimensional hollow cylinder, and the numerical solutions are found to be consistent with existing analytical solutions. Furthermore, the effects of relaxation time on the non-Fourier heat transfer process in three-dimensional hollow cylinder and complex ceramic part are discussed. Importantly, the method presented in this paper is not influenced by the coordinate system or the shape of the calculated region, providing a theoretical reference for solving complex three-dimensional non-Fourier heat transfer problems. [ABSTRACT FROM AUTHOR]

In special launch scenarios such as armament and aerospace, the scale of the launch system is severely restricted, which causes unstable combustion of propellant. An embedded structure for the small propulsion system driven by solid propellant is proposed to overcome this problem. This study aims to demonstrate the two-phase flow behaviors and launch safety of the combustion chamber with an embedded structure. A two-dimensional two-phase flow model based on the modified two-fluid theory is developed to describe the detailed two-phase flow behaviors in the combustion chamber during launching. Different from most of the existing studies, the constitutive equations determined from actual physical conditions are used to close the system of continuity equations. The numerical results are compared with that of the experiment to verify the accuracy of the numerical model. On this basis, the launch performance of the embedded structure is investigated. The numerical results indicate that the embedded structure facilitates the ignition process and reduces the risk of excessive pressure, but decreases the muzzle velocity at the same time. In addition, the effect of design parameters on launch safety is further investigated. Design parameters directly affect the launch safety, and the selection of reasonable parameters is a useful method for enhancing the launch performance. [ABSTRACT FROM AUTHOR]

In order to simultaneously maintain the ship magnetic field modeling accuracy, reduce the number of coefficient matrix conditions and the model computational complexity, an improved composite model is designed by introducing the magnetic dipole array model with a single-axis magnetic moment on the basis of the hybrid ellipsoid and magnetic dipole array model. First, the improved composite model of the ship's magnetic field is established based on the magnetic dipole array model with 3-axis magnetic moment, the magnetic dipole array model with only x-axis magnetic moment, and the ellipsoid model. Secondly, the set of equations for calculating the magnetic moments of the composite model is established, and for the problem of solving the pathological set of equations, the least-squares estimation, stepwise regression method, Tikhonov, and truncated singular value decomposition regularization methods are introduced in terms of the magnetic field, and generalized cross-validation is used to solve the optimal regularization parameters. Finally, a ship model test is designed to compare and analyze the effectiveness of the composite and hybrid models in four aspects: the number of coefficient matrix conditions of the model equation set, the relative error of magnetic field fitting, the relative error of magnetic field extrapolation, and the computational time complexity. The modeling results based on the ship model test data show that the composite model can be used for modeling the magnetic field of ships, and compared with the hybrid model, it reduces the number of coefficient matrix conditions and improves the computational efficiency on the basis of retaining a higher modeling accuracy, and it can be effectively applied in related scientific research and engineering. [ABSTRACT FROM AUTHOR]

In order to solve the problem of magnetic targets magnetic field modeling, a magnetic dipole array model was established, a modeling inversion equation system was constructed, and the degree of sickness of the solved equation system under different numbers of magnetic dipoles was quantitatively analyzed based on the coefficient matrix condition number. In order to solve the problem of the pathological system of magnetic field modeling equations, a regularization method based on the conjugate gradient least squares method was designed to invert the magnetic moment parameters of the magnetic dipole. In order to analyze the applicability of the regularization method in magnetic field modeling inversion, the magnetic moment solving accuracy, the magnetic moment solving robustness, calculation time, and other metrics are defined. A detailed test of the ship model was designed, and the magnetic field passing characteristics of the two types of ship models at different positive and horizontal conditions at two depths were measured. Under the condition of no interference and interference, the conjugate gradient least squares method is used to invert the magnetic field model, and the numerical test analysis shows that the conjugate gradient least squares method has higher applicability than the generalized inverse solution method and the stepwise regression method. Under the condition of interference, the relative error of magnetic field fitting of the array model with 15 magnetic dipoles is 0.1537, and the relative error of magnetic field extrapolation is 0.0868. The method proposed has the advantages of high accuracy and strong robustness in solving the magnetic moment of the magnetic dipole array model. [ABSTRACT FROM AUTHOR]

In order to study the simulation ability of a solenoid on a ship magnetic field, a new composite model based on a double row magnetic dipole array model with an ellipsoid was designed. The time-domain characteristics, such as magnetic field characteristics, magnetic inclination cosine, magnetic field scalar gradient, and magnetic field spatial distribution characteristics, were extracted. It was verified that the model can accurately simulate the magnetic field characteristics of ships through ship model experiments and simulation analysis. To further quantitatively and accurately analyze the simulation ability of the composite model for ship magnetic fields, a dynamic time wrapping measurement method based on one-dimensional time series was adopted to calculate the similarity of four characteristic quantities: magnetic field vector, magnetic field modulus, magnetic inclination cosine, and magnetic field scalar gradient. The results showed that the composite model has high simulation ability for ship magnetic fields. [ABSTRACT FROM AUTHOR]

Herein, for the continuous casting of round blooms with strand electromagnetic stirring, the effects of rotating magnetic field (RMF) and spiral magnetic field (SMF) on the electromagnetic, fluid flow, heat transfer, solidification, and macrostructure are investigated by numerical simulation and industrial experiments, respectively. The results show that the molten steel flows in a spiral shape along the casting direction with the RMF and SMF. Due to the influence of secondary flow caused by electromagnetic stirring (EMS), and the zone of high velocity of molten steel accounts for 13.7% of the whole stirring range with the RMF. The SMF has a strong stirring effect in the whole range of secondary flow, the zone of high velocity of molten steel accounts for 49.1% of the whole stirring range, and the liquid fraction of the SMF at the liquid core is also lower. The results of the industrial experiments prove that the SMF has a wider stirring depth than the RMF, and the center crack range is significantly reduced. [ABSTRACT FROM AUTHOR]

Summary: An analysis and design method of the equalization circuit based on switched‐capacitor (SC) units and graph networks is proposed in this paper. In the analysis method, the SC equalization circuit is decomposed into multiple SC units and one or more graph networks, which can simplify the analysis process. The effects of circuit parameters and structure on the equalization performance are analyzed in detail. And the average resistance distance among cells is proposed to mathematically analyze and compare the equalization path of the SC equalization circuits. Based on four types of SC units and graph networks of the equalization circuit, a design method of the SC equalization circuit and two SC equalization circuits are proposed. The proposed SC equalization circuit based on cell equalization units has the optimal equalization speed. The proposed SC equalization circuit based on cell equalization units and substring equalization units implements the trade‐off between equalization speed and device number. Simulation and experimental results are provided to verify the validity of the proposed analysis method and SC equalization circuits. [ABSTRACT FROM AUTHOR]

One of the essential issues for spacecraft is maintaining the combustion chamber wall from exceeding acceptable temperatures. The cooling channels' thermal resistance and flow topology can be augmented by adding ribs to the heated surface. The present work proposed a Novel X-shape rib to enhance the thermal efficiency of hydrogen regenerative-cooling channels. The numerical investigation was carried out for the cooling system with rectangular and trapezoidal X-shape ribs at various attack angles (30 ° , 45 ° , and 60 °). The investigation findings demonstrated that both X-shape rib constructions optimized the cooling system's thermal efficiency. Since the trapezoidal X-shape ribs' chamfering angle reduces the resistance to coolant flow, the pressure loss of these ribs is less than rectangular ribs. Additionally, the heat transfer rate is maximum for 30 ° X-shape ribs, decreasing gradually with the increase of the X-shape rib's attack angle. Furthermore, compared to a smooth channel, the rectangular 30 ° X-shape ribs enhance the thermal efficiency by 44 % while reducing the wall temperature by 24 %. • The thermal efficiency of the channel with X-shape rib was numerically calculated. • Six X-shape ribs' performance was evaluated and compared to the smooth channel. • Heat transfer rate is maximum for 30 ° X ribs, inversely proportional to attack angle. • The rectangular 30 ° X ribs enhance thermal efficiency by 44 % relative to the flat channel. [ABSTRACT FROM AUTHOR]

Intrinsic or acquired chemoresistance represents a major obstacle in cancer treatment. Multiple mechanisms can contribute to cancer cells' resistance to chemotherapy. Among them, an aberrantly strengthened DNA repair mechanism is responsible for a large proportion of drug resistance to alkylating agents and radiation therapy. In cancer cells, damping overactivated DNA repair system can overcome survival advantages conferred by chromosomal translocations or mutations and lead to cytostatic effects or cytotoxic. Therefore, selectively targeting DNA repair system in cancer cells holds promise for overcoming chemoresistance. In this study, we revealed that the endonuclease Flap Endonuclease 1 (FEN1), essential for DNA replication and repair, directly interacts with phosphatidylinositol 3-phosphate [PI(3)P], and FEN1-R378 is the primary PI(3)P-binding site. PI(3)P-binding deficient FEN1 mutant (FEN1-R378A) cells exhibited abnormal chromosomal structures and were hypersensitized to DNA damage. The PI(3)P-mediated FEN1 functionality was essential for repairing DNA damages caused by multiple mechanisms. Furthermore, VPS34, the major PI(3)P synthesizing enzyme, was negatively associated with patients' survival in various cancer types, and VPS34 inhibitors significantly sensitized chemoresistant cancer cells to genotoxic agents. These findings open up an avenue for counteracting chemoresistance by targeting VPS34-PI(3)P-mediated DNA repair pathway, and call for assessing the efficacy of this strategy in patients suffering from chemoresistance-mediated cancer recurrence in clinical trials. [Display omitted] •.With R378 as its primary PI(3)P-binding site, FEN1 functions as a new PI(3)P-binding protein. • PI(3)P-FEN1 interaction contributes to FEN1-mediated DNA repair. • VPS34 can be an effective drug target in enhancing sensitivity to genotoxic agents and combating chemoresistance. [ABSTRACT FROM AUTHOR]

Background: Breast cancer is a typically diagnosed and life‐threatening cancer in women. Thus, dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) is increasingly used for breast lesion detection and diagnosis because of the high resolution of soft tissues. Moreover, supervised detection methods have been implemented for breast lesion detection. However, these methods require substantial time and specialized staff to develop the labeled training samples. Purpose: To investigate the potential of weakly supervised deep learning models for breast lesion detection. Methods: A total of 1003 breast DCE‐MRI studies were collected, including 603 abnormal cases with 770 breast lesions and 400 normal subjects. The proposed model was trained using breast DCE‐MRI considering only the image‐level labels (normal and abnormal) and optimized for classification and detection sub‐tasks simultaneously. Ablation experiments were performed to evaluate different convolutional neural network (CNN) backbones (VGG19 and ResNet50) as shared convolutional layers, as well as to evaluate the effect of the preprocessing methods. Results: Our weakly supervised model performed better with VGG19 than with ResNet50 (p < 0.05). The average precision (AP) of the classification sub‐task was 91.7% for abnormal cases and 88.0% for normal samples. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.939 (95% confidence interval [CI]: 0.920–0.941). The weakly supervised detection task AP was 85.7%, and the correct location (CorLoc) was 90.2%. A sensitivity of 84.0% at two‐false positives per image was assessed based on free‐response ROC (FROC) curve. Conclusions: The results confirm that a weakly supervised CNN based on self‐transfer learning is an effective and promising auxiliary tool for detecting breast lesions. [ABSTRACT FROM AUTHOR]

In this paper, we study the influence of different regularization schemes on the critical endpoint (CEP) of chiral phase transition within a cubic box with volume V ∼ L 3 . A two-flavor Nambu–Jona-Lasinio model at finite temperature T and chemical potential μ is adopted as the effective model of the strong interacting matter. Due to the finite volume of the box, the momentum integral in gap equation is replaced by discrete summation, and an anti-periodic boundary condition for quark field is applied. We employ the Schwinger's proper time and the Pauli–Villars regularization (PVR) schemes, respectively. It is found that the first-order phase transition line displays an intriguing "staircase" behavior, and eventually disappears as T increases. In particular, there is no existence of the CEP for both regularization schemes in infinite volume limit V → ∞. However, for the finite volume, the locations of the CEPs with proper time and PVR are determined, respectively. [ABSTRACT FROM AUTHOR]

Electron kinetics plays an essential role in CO2 splitting in non-equilibrium plasmas. Indigenous resources, particularly CO2 rich in the Martian atmosphere, are utilized as the feedstock for the technology of in situ propellant production (ISPP) in Mars missions. To obtain electron kinetics including electron energy distribution function (EEDF) and transport coefficients, a Boltzmann analysis is adopted. In view of ISPP in the upper Martian atmosphere, the complicated variation of the gas composition with the altitude in both dayside and nightside is considered. The composition of gas mixture is derived from the previous measurement data through site survey and numerical models. According to the results of calculation, altitude affects the behavior of EEDFs and transport coefficients in both dayside and nightside. The rapid drop in CO2 content and the rise in O content with altitude lead to a broader EEDF. The reduction of the critical breakdown electric field strength with the increasing altitude is ascribed to the combined effects of the decline of the attachment coefficient and enhancement of the ionization coefficient. The electron energy loss mechanism is presented for the analysis of energy efficiency. At low mean electron energy, electron energy is mostly transferred to vibrational levels of CO2. With the increasing electron energy, more energy-demanding processes, like ionization and electronic excitation, become essential pathways of energy loss. [ABSTRACT FROM AUTHOR]

The experiments of underwater discharges in an anechoic pool were carried out and analysis of the time-frequency characteristics of the acoustic signals was conducted based on Variational Mode Decomposition and Hilbert–Huang Transform (VMD-HHT). We propose a relative center frequency difference method to determine the decomposition numbers K which has to be given before the application of VMD and the result is satisfying. The HHT spectrum and marginal spectrum are obtained, then, some valuable conclusions are drawn. The high-frequency components of the acoustic signal are mainly attributed to the shock wave, and the low-frequency components mostly result from the bubble pulse. The frequency range of the acoustic signal is basically from 0 to 90kHz, and the ratio of energy in the low-frequency band(0–4kHz) to that of the total acoustic signal is up to 55.56%. Furthermore, this ratio versus gaps is also explored and it has the minimum at the gap of 1.5 mm which is the optimal gap for the peak pressure and radiated energy of the acoustic signal. Therefore, we can not obtain the maximum energy of the acoustic signal and the maximum ratio in the low-frequency band simultaneously. [ABSTRACT FROM AUTHOR]

Simple Summary: We aim to discover the ideal biomarkers for diagnosing HCC, by detecting the small RNAs (sRNAs) from serum exosomes. After analyzing the proportion and distribution of sRNAs species from serum exosomes, we found that miRNAs were the most important components in serum exosomes. Three serum-exosome-derived miRNAs (miR-122-5p, let-7d-5p, and miR-425-5p) had significant values for diagnosing HCC, both in the training set and validation set. Our results concluded that serum-exosome-derived miRNAs could be the promising biomarkers in HCC diagnosis Background: Serum exosomes are emerging as key liquid biopsy biomarkers for the early diagnosis of cancer. However, the proportion and distribution of small RNA (sRNA) species from serum exosomes of hepatocellular carcinoma (HCC) patients remain unclear. Effective and reliable biomarkers for HCC diagnosis should be explored. Methods: In this study, we aimed to use sRNA sequencing to profile the sRNAs of serum exosomes in HCC and non-tumor donors. The serum exosomes of 124 HCC patients and 46 non-tumor donors were enrolled for detecting the values of the potential biomarkers for the diagnosis of HCC. Results: We found that miRNAs accounted for the maximal percentage of all types of sRNAs both in the serum exosomes of HCC patients and non-tumor donors. This indicated that the serum-exosome-derived microRNAs (miRNAs) were the most valuable as potential biomarkers in HCC diagnosis. Then, miRNAs were set as research candidates. In our Chinese cohorts, three serum-exosome-derived miRNAs (miR-122-5p, let-7d-5p, and miR-425-5p) could be promising biomarkers for distinguishing HCC patients from non-tumor donors. In addition, they were preferred for the early diagnosis of HCC. We also presented the base distribution of some novel serum-exosome-derived miRNAs and described the potential values as biomarkers. Conclusions: The results suggested that the serum-exosome-derived miRNAs were the most crucial sRNA species and they highlighted the potential of serum-exosome-derived miRNAs as promising biomarkers for HCC diagnosis. [ABSTRACT FROM AUTHOR]

Simple Summary: Colorectal cancer (CRC) is generally diagnosed at an advanced stage, when chemo- and targeted therapies can only achieve a limited increase in overall survival for these patients. The activation of insulin/IGF-dependent pathways has been established as a key step that contributes to several mechanisms of CRC resistance to conventional and targeted therapeutic drugs. In this study, we tested the combinatory effect of the novel IGF-1R inhibitor PB-020 and MBZ or anti-PD-1 against CRC, respectively. The PB-020/MBZ combination significantly reduced the pAKT1-S473 level, dampened the viability of CRC cells and blocked CRC progression in a xenograft model. More importantly, the PB-020/anti-PD-1 combination synergistically blocked CRC propagation in the MC38 murine colon carcinoma model. RNA-seq analysis indicated that PB-020 and the anti-PD-1 antibody synergistically suppressed the transcription of the PI3K/AKT pathway genes. These findings establish a preclinical proof-of-concept for tackling CRC using a combination of PB-020 and clinically approved anticancer drugs. CRC is one of the leading causes of cancer mortality worldwide. Chemotherapy is widely used for the treatment of CRC, but its efficacy remains unsatisfactory, mainly due to drug resistance. Therefore, it is urgent to develop new strategies to overcome drug resistance. Combination therapy that aims to achieve additive or synergistic therapeutic effects is an effective approach to tackle the development of drug resistance. Given its established roles in tumor development, progression and metastasis, IGF-1R is a promising drug target for combination therapy against CRC. In this study, we revealed that the novel IGF-1R inhibitor PB-020 can act synergistically with mebendazole (MBZ) to reduce the viability of CRC cells and block xenograft CRC progression. Moreover, the PB-020/anti-PD-1 combination synergistically blocked CRC propagation in the MC38 murine colon carcinoma model. Both combination therapies potently suppressed the PI3K/AKT signaling pathway genes in CRC that may be associated with the development of drug resistance. Our findings establish a preclinical proof-of-concept for combating CRC using combined multi-target treatment with PB-020 and clinical anticancer drugs, which may provide useful clues for clinical trials to evaluate the efficacy and safety of these drug combinations in CRC patients. [ABSTRACT FROM AUTHOR]

Deposition on heat exchange surfaces is an urgent problem to be solved to achieve efficient utilization of energy in thermal equipment. To mitigate deposition and the resultant heat attenuation, this work proposes a mixed tube bundle strategy of inserting attached cylinders behind the tube bundle, which can effectively meet the design requirements of high anti-deposition performance, high heat transfer efficiency, and low flow resistance. An integrated dynamic model for deposition is developed to elucidate the effect of ash particles on deposition, flow, and heat transfer characteristics. Based on the inverse distance weighting interpolation, a dynamic mesh smoothing technique is employed to simulate the evolving deposition layer on the heat transfer surface. In addition, the L 16 (43) orthogonal experimental design method is adopted to study the influence of the arrangement angle, diameter, and distance to the primary bundle of the attached cylinder on the overall performance, and determine the optimal scheme. The results show that deposition in the cases using the mixed tube bundle strategy has significantly decreased. The weakening effects of the attached cylinder on the deposition of small-medium particles and large-sized particles are due to the inhibition of vortex development in the gap of tube bundle and the deviation of the motion trajectory, respectively. The novel design exhibits the lowest deposition mass M dep = 1.12 g and the best comprehensive performance PEC = 1.14 under the condition of the arrangement angle of 50°, the diameter of 10 mm, and the distance between the primary bundle of 5 mm. The obtained results can provide reference schemes and guidance for the optimization of the design of heat exchange equipment and accessory devices. [Display omitted] • A mixed tube bundle strategy is proposed to improve anti-deposition. • An integrated dynamic deposition model is developed. • Orthogonal experimental design method is adopted to determine the optimization scheme. • Influencing factors of multiple optimization indicators are analyzed. [ABSTRACT FROM AUTHOR]

The ejector can create a vacuum environment without electricity and produce no pollutants, making it widely used in various fields. However, during the working process, a large amount of high-pressure air needs to be continuously supplied to maintain the vacuum level. Given the current energy shortages, it is essential to enhance the entrainment capacity and reduce the energy requirements of the vacuum ejector. To achieve this goal, a two-stage vacuum ejector (TSVE) and structure optimization are adopted. While achieving the same vacuum level (80 kPa or 90 kPa), the air consumption ( m ˙ p) and entrainment ratio (Er) of vacuum ejectors with various shapes are compared. Through structural optimization, five high-performance vacuum ejectors (P p < 0.6 MPa, Er > 0.65) are selected. Computational Fluid Dynamics (CFD) is applied to observe the mixing processes in the vacuum ejector. In addition, the optimized vacuum ejector and TSVE are compared to the original one. An experimental system is designed for this purpose. The findings indicate that both methods can enhance the performance of the vacuum ejector. However, the benefits of TSVE are more pronounced at lower vacuum levels, while the advantages of the optimized vacuum ejector become more obvious as the vacuum level increases. • Two methods are proposed to improve the performance of vacuum ejectors. • The advantages of TSVE are more pronounced at lower vacuum degrees. • As the vacuum increases, the optimized vacuum ejector is more effective. • Provide a reference for the design of vacuum ejectors to suit various occasions. [ABSTRACT FROM AUTHOR]

Ash deposition is a key issue that limits the energy utilization and safety operation of high-energy-consuming equipment in industrial applications, and the clarification of the heat and mass transfer process under ash deposition is vital. To improve the anti-deposition performance of tube bundles and mitigate heat transfer deterioration, a mixed strategy with attached small cylinders arranged behind the tube has been proposed, which overcomes the difficulties faced by irregular and extended surface tube bundles in manufacturing, cleaning, maintenance, and energy consumption. A CFD model incorporating multiple deposition mechanisms is established to investigate the dynamic deposition behavior, heat transfer characteristics, and comprehensive performance of the tube bundles. In particular, the dynamic growth process of the deposition layer on heat transfer surface in this work is achieved through a dynamic mesh smoothing method based on inverse distance weighting interpolation. Parametric studies are conducted on different arrangements and angles (α = 15° - 65°) of the attached cylinders to obtain the optimal comprehensive performance design. The results show that the attached cylinders suppress the formation and development of the wake vortex caused by the primary tube bundle, significantly enhancing the anti-deposition performance of the tube bundles. The length of vortex evolution increases and the separation point of the boundary layer extends with the angles, leading to a transition of the vortex shedding regime between tube bundles. Compared to the benchmark case, Case 1 exhibits a higher anti-deposition and heat transfer performance, where the deposition mass decreases by 43.98% and the PEC reaches the maximum value of 1.11 at α = 45°, which delivers the best comprehensive performance. The results can provide more realistic predictions for the practical design, operation, and maintenance of thermal equipment. [ABSTRACT FROM AUTHOR]

The low thermodynamic cycle efficiency of the plasma synthetic jet actuator (PSJA) limits its application in flow control of supersonic aircraft. To improve the thermodynamic cycle efficiency of the PSJA, the energy conversion process of the PSJA under single discharge has been investigated by thermodynamic theory analysis and numerical simulation. The relations between thermodynamic cycle efficiency, specific heat ratio of gas medium, non-dimensional energy deposition and heating efficiency are established by theoretical deduction. Employing the three-dimensional nonconstant electrode center energy deposition model, energy conversion processes in the PSJA with six different gas mediums have been investigated. The simulation results show that the thermodynamic cycle efficiency of the PSJA with noble gas medium can exceed 3.2 %, which is 1.92 times of the PSJA with air medium due to their low volume specific heat. The maximum jet x-velocity of helium can reach 493.11 m/s, which is 3.3 times higher than that of air. Consequently, noble gases prove to be effective in improving the thermodynamic cycle efficiency of the PSJA and enhancing the strength of the synthetic jet. The advancement in the performance of the PSJA contributes to their enhanced capabilities in the field of active flow control. [ABSTRACT FROM AUTHOR]

Keeping the combustion chamber walls at a sufficiently low temperature ensures liquid rocket engines' safe and reliable operation. The most promising method to achieve that is the heat transfer enhancement techniques which optimize the heat transfer coefficient and increase the thermo-hydraulic performance. The present work is concerned with numerical studies on the effect of the pentagonal V-shape ribs to enhance the heat transfer coefficient of the rocket engine's cooling channels. Numerical simulations for various chamfering angels of the pentagonal V-shape rib are performed by the (S S T , k − ω) turbulent model. The simulation findings show that the overall performance of the ribbed channel improved inversely with the pentagonal chamfering angle. Compared with a conventional channel, the average Nusselt Number and thermal-hydraulic performance of the ribbed channel enhanced up to 66.6 % and 52 % respectively, and the 5 ° pentagonal V-shape rib has higher thermal-hydraulic performance with a slight high the pressure loss penalty. • The influence of pentagonal V-shape ribs in thermal performance was numerically studied. • Four pentagonal V-shape ribs are investigated and compared with the smooth cooling channel. • The ribbed channels' thermal performance improved inversely with the chamfering angle. • 5 ° pentagonal V-shape has higher thermal performance compared with the smooth channel. [ABSTRACT FROM AUTHOR]

We constructed an underwater discharge system to conduct a number of experiments. Considering the constant resistance of the plasma channel, we got an analytic expression for the current containing unknown parameters on the basis of the Kirchhoff voltage law. Therefore, we are required to determine the total circuit resistance R with the measured current data in hand. Three methods are employed to get this job done, namely, nonlinear least squares with three variables (NLS-TV), nonlinear least squares with a single variable (NLS-SV), and waveform calculation method (WCM). The Levenberg–Marquardt (L-M) algorithm and particle swarm optimization (PSO) algorithm are employed in NLS-TV and NLS-SV, and the root mean square error (RMSE), as well as an improved cosine similarity (ICS), was selected to evaluate the performance of algorithms. The results show that NLS-TV gives an optimal solution with the combination of the PSO algorithm and L-M algorithm. Then, by calculation, R = 1.3195 Ω , C = 0.56865 μF, and L = 17.172 μH. RMSE and ICS between fitted current data and measured one are 43.9689 and 0.9947, respectively. NLS-SV gives a satisfying solution either by PSO or by L-M, yet it needs information of angular frequency from the measured current waveform and the total inductance C. In this case, we get R = 1.3115 Ω , L = 16.969 μH, RMSE = 48.0883, and ICS = 0.9967. As for WCM, it is completely dependent on the measured current waveform and the total inductance C. The corresponding values of R and L are 1.2463 Ω and 16.993 μH. Also, we get RMSE = 52.1902 and ICS = 0.9728. For NLS-SV and WCM, the needed total capacitance during calculation is determined using the computed capacitance by NLS-TV. If the energy storage capacitance is used as the total capacitance, the obtained solution is frustrating. Therefore, independent use of NLS-SV or WCM demands a precise capacitance of the total circuit measured by an RLC meter. We also draw a conclusion that ignoring the capacitance of other parts of the circuit is incorrect and will lead to an enormous error during calculation. [ABSTRACT FROM AUTHOR]

One of the most critical issues in supersonic flight is the thermal protection of the rocket engine combustion chamber. The ribs' construction can improve heat transfer and coolant flow characteristics significantly. Ansys fluent was used to investigate the supercritical hydrogen fuel flow and heat transfer characteristics. Ribs spacing of 10 mm, 5 mm, and 2.5 mm were compared to determine the optimal spacing required to achieve maximum cooling influence and lower pressure drop to safeguard the overheated structure and lower the temperature of the walls. Compared to the smooth channel, the thermal performance factor and pressure drop of the 5 mm spacing increased by 32.5% and 16.64%, respectively, while the maximum temperature reduced by 12.07%. Therefore, the cylindrical rib construction with a 5 mm spacing is perfect for improving heat transfer, has acceptable pressure drops, and reduces thermal stratification inside the channel. • Cylindrical ribs improved transmission and turbulent flow qualities. • The maximum heated wall temperature decreased by 12.07%. • The thermal performance factor is considerably enhanced by a maximum of 32.5%. • Cylindrical ribs decreased non-uniform temperature distribution behaviour. • Cooling capacity achieved the best value at 5 mm rib's spacing. [ABSTRACT FROM AUTHOR]

This article proposes a two-mode active balancing circuit for series-connected cell strings. The proposed balancing circuit has two operation modes: any cell to any cell (AC2AC) and direct cell to cell (DC2C) modes. In AC2AC mode, the balancing circuit can be equivalent to an improved switched-capacitor (SC) balancing circuit, and the energy is transferred among all imbalanced cells, implementing the higher balancing speed when the voltage gap between cells and the number of imbalanced cells are large. In DC2C mode, the proposed balancing circuit can be equivalent to a balancing circuit based on three-resonant-state LC unit, and the energy is transferred from the highest voltage cell to the lowest voltage one, achieving the higher balancing efficiency and speed as well as accuracy when the voltage gap between cells is small. The operation state, balancing power, and balancing efficiency of each mode are analyzed in detail. The control strategy and design considerations of the balancing circuit are introduced to obtain the optimal balancing performance. Experimental results are provided to verify the validity of the proposed balancing circuit. The results show that the proposed balancing circuit achieves high balancing accuracy and efficiency as well as balancing speed. [ABSTRACT FROM AUTHOR]

This numerical study investigates the dynamics around a single Taylor bubble rising with small-dispersed bubbles in a vertical pipeline. The Volume-of-fluid (VOF) method in Ansys Fluent 18.1 is used to track the Taylor bubble, and the Discrete Particle Method (DPM) is used to track the small-dispersed bubbles, for the following parameter range; 812 ⩽ Re ⩽ 5684 , E o = 94 and log (M o) = - 10.6 . The coupling strategies for both the continuous gas–liquid phase as well as the discrete bubble phase are all accounted for in the numerical calculations. The dispersed bubbles significantly affect the behaviour of the rising Taylor bubble in numerous ways. The terminal velocity increases with an increase in the number of dispersed bubbles. The rise velocity is, however directly correlated with the deformation of the nose of the bubble. The flow dynamics around the nose of the Taylor bubble are stronger for low velocities due to lower inertia. The computations also demonstrated that there are both acceleration and deceleration effects on the Taylor bubble. Our predictions are in quantitative agreement with published experimental results by Cerqueira and Paladino (Int. J. Multiph. Flow, vol. 133, p. 103,450, Dec. 2020). [ABSTRACT FROM AUTHOR]

The cooling capacity of regenerative cooling channels is still insufficient for the liquid rocket engine due to the high temperature of the combustion chamber and the little refrigerant mass flow. To improve the thermo-hydraulic performance of the combustion chamber wall, a V-shape rib is proposed, and its effect on heat transfer and pressure drop is investigated. Numerical models are built of a regenerative cooling channel with V-shape rib using CFD commercial software. Simulation results showed that V-shape ribs enhance convection heat transfer and improve thermo-hydraulic performance by 23 % compared to smooth cooling channels. Although the maximum temperature was reduced by 20.9 % , the flow resistance increased slightly. The overall heat transfer coefficient of the cooling channel with 30 ∘ V-shape rib is superior to that of the 60 ∘ and 45 ∘ V-shape ribs, and 30 ∘ V-shape rib with 10 m m pitch has the best cooling capacity. • A low temperature of the rocket engine chamber wall is essential to ensure safe operation. • Three V-shape ribs are investigated and compared with the smooth regenerative cooling channel. • 30° V-shape rib has a better thermo-hydraulic performance than the 60° and 45° V-shape ribs. [ABSTRACT FROM AUTHOR]

Summary: This study provides an overview of green supply chain management (GSCM) in the context of renewable energy sources. Thus, it establishes a green management standard with GSCM that companies can adopt. The environmental, economic, and social components determine the concept of GSCM. However, the development and commercialization of renewable energy and sustainable manufacturing practices play a fundamental role in shaping the traditional supply chain management (SCM) and business models. GSCM means that firms and organizations must balance economic and environmental performance to stay competitive, and conform with regulatory and community pressures. This has forced enterprises to design and implement strategies such as eco‐efficiency, greener production, and cleaner environmental practices, for green management practices, which aim at reducing the environmental impacts of their operations. This study further highlights insights needed to significantly improve performance and overcome barriers to the development of renewable energy green supply chain management (REGSCM). It also presents useful techniques by outlining better control chain costs to make renewable energy more affordable and efficient, and a new conceptual model that is mainly grounded within the network of distributed energy systems in the context of GSCM. This concept allows renewable energy producers to sell their surplus electricity based on a peer‐to‐peer (P2P) network or sell directly via the general market. Specifically, this model brings to bear the linkages to the creation of value by firms. [ABSTRACT FROM AUTHOR]

Ash deposition is a critical issue concerning the energy utilization and safety operation of heat exchangers. Efficient dynamic evaluation of deposition morphology and reasonable structural parameters contribute to the deposition prediction and the improvement of deposition resistance. In this work, a transient deposition model is established to investigate the dynamic deposition behavior and comprehensive performance. To realize the real-time update of deposition layer morphology, a simple and easy-to-implement dynamic mesh smoothing method based on inverse distance weighted (IDW) interpolation is proposed and then validated by experiments. The effect of the deposition layer dynamic evolution on the particle impact characteristics and the thermal-hydraulic performance of tube bundles is highlighted. In addition, parametric studies are performed on the tube arrangement to obtain the optimal comprehensive performance design. The results show that the angles and velocities of particles impacting the first tube and downstream tubes present a triangular distribution and a butterfly-shaped spatial distribution, respectively. Due to the guidance of the deposition layer on the trajectory of gas and ash particles, the particle impact region on the windward side is more concentrated when using the dynamic mesh model, and the entrainment of small-sized particles is intensified. Besides, the rise in longitudinal spacing significantly exacerbates the deposition and heat transfer deterioration. According to the comprehensive evaluation, the case at S L / D = 2.5 exhibits a higher deposition resistance and heat transfer performance. These results can provide more realistic predictions and indications in practical thermos-equipment design. [Display omitted] • Novel IDW dynamic mesh method can realize morphology evolution of deposition. • Angles and velocities of particles impacting the tube show triangular and butterfly-shaped spatial distribution. • Growth of deposition layers changes the motion trajectory of particles. • Development of flow patterns and vortices affects particle impact and deposition behavior. [ABSTRACT FROM AUTHOR]

Extreme drag and aerodynamic heat are the main penalties for blunt forebody of supersonic vehicles. This results in shorter flight range and higher fuel consumption, and aerodynamic heat seriously affects the performance of internal electronics. In the current study, the flow field mechanism of a blunt body model with a supersonic opposing jet in a supersonic flow field is numerically study. The physical model is a two-dimensional axisymmetric blunt forebody model with a convergent nozzle structure, and the numerical calculation model is a coupling of the two-dimensional axisymmetric Reynolds average method and the shear stress transport(SST) turbulence model. The calculation results in this paper are compared with the experimental data in the literature, which verifies the accuracy, and the calculation verifies the grid independence. An active flow control method that controls a single pressure parameter is proposed, and the formation process of the opposing jet in the convergent nozzle is considered, and the flow field structure of the opposing jet formed by the convergent nozzle with different nozzle sizes is studied. The results show that a single pressure parameter can control the formation of a supersonic opposing jet to form a long penetration mode and a short penetration mode. The ratio of the ambient pressure to the jet pressure at the stagnation point of the blunt body can directly affect the flow field structure of the opposing jet, and reasonable control of opposing jet parameters is an effective way for thermal protection and drag reduction of blunt body structures. • The internal flow field of the opposing jet convergent nozzle is considered. • Verify the analytical and numerical solutions of the isentropic flow in the nozzle. • Verify the reliability of the code through experimental data. • Analyze the influence of a single pressure parameter on the external flow field. [ABSTRACT FROM AUTHOR]

Acoustic signals generated by underwater spark discharge (UWSD) can be used in a wide range of applications. The characteristics with different electrode configurations need further study for more practical application. The generation mechanism and the main characteristic indices of UWSD acoustic signals were analyzed. The acoustic signal time-frequency characteristics with different electrode gap distances and materials were calculated and compared. The results show that there is an electrode gap distance that maximizes the energy of the acoustic signal, and this gap distance is related to the impedance matching between the discharge channel and the external circuit. The proportion of low-frequency components in the acoustic signal decreases with the increase in the electrode gap distance. [ABSTRACT FROM AUTHOR]

The control of discharge mode and the optimization of energy efficiency are of particular concern as the significant impact on the application of the underwater plasma discharge system. In this paper, the RLC parameters of each part of the underwater discharge system are investigated, and the equivalent circuit is obtained. Typical waveforms of current and voltage for different underwater discharge modes are displayed. The correlation between the equivalent RLC parameters of the discharge system and the discharge modes and energy is illustrated. The equivalent circuit of the underwater plasma discharge system is utilized to analyze the effects of the power source, electrode, and liquid dielectric parameters. The influences of these parameters can be identical to the impacts on the RLC parameters of the underwater discharge system equivalent circuit simultaneously, and then, the effects on the discharge modes and energy can be better understood. It can be concluded that the relative relationship of system equivalent RLC parameters determines the discharge mode, and the impedance matching between the discharge channel and the external circuit determines the discharge energy. [ABSTRACT FROM AUTHOR]

Paraventricular thalamus (PVT) is a midline thalamic area that receives dense GABA projections from zona incerta (ZI) for the regulation of feeding behaviours. Activation of central serotonin (5‐HT) signalling is known to inhibit food intake. Although previous studies have reported both 5‐HT fibres and receptors in the PVT, it remains unknown how 5‐HT regulates PVT neurons and whether PVT 5‐HT signalling is involved in the control of food intake. Using slice patch‐clamp recordings in combination with optogenetics, we found that 5‐HT not only directly excited PVT neurons by activating 5‐HT7 receptors to modulate hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels but also disinhibited these neurons by acting on presynaptic 5‐HT1A receptors to reduce GABA inhibition. Specifically, 5‐HT depressed photostimulation‐evoked inhibitory postsynaptic currents (eIPSCs) in PVT neurons innervated by channelrhodopsin‐2‐positive GABA axons from ZI. Using paired‐pulse photostimulation, we found 5‐HT increased paired‐pulse ratios of eIPSCs, suggesting 5‐HT decreases ZI–PVT GABA release. Furthermore, we found that exposure to a high‐fat–high‐sucrose diet for 2 weeks impaired both 5‐HT inhibition of ZI–PVT GABA transmission and 5‐HT excitation of PVT neurons. Using retrograde tracer in combination with immunocytochemistry and slice electrophysiology, we found that PVT‐projecting dorsal raphe neurons expressed 5‐HT and were inhibited by food deprivation. Together, our study reveals the mechanism by which 5‐HT activates PVT neurons through both direct excitation and indirect disinhibition from the ZI. The downregulation in 5‐HT excitation and disinhibition of PVT neurons may contribute to the development of overeating and obesity after chronic high‐fat diet. Key points: Serotonin (5‐HT) depolarizes and excites paraventricular thalamus (PVT) neurons. 5‐HT7 receptors are responsible for 5‐HT excitation of PVT neurons and the coupling of hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels to 5‐HT receptors in part mediates the excitatory effect of 5‐HT.5‐HT depresses the frequency of spontaneous inhibitory but not excitatory postsynaptic currents in PVT neurons. 5‐HT1A receptors contribute to the depressive effect of 5‐HT on inhibitory transmissions.5‐HT inhibits GABA release from zona incerta (ZI) GABA terminals in PVT.Chronic high‐fat diet not only impairs 5‐HT inhibition of the ZI–PVT GABA transmission but also downregulates 5‐HT excitation of PVT neurons.PVT‐projecting dorsal raphe neurons express 5‐HT and are inhibited by food deprivation. [ABSTRACT FROM AUTHOR]

Silicon semiconductors with excellent thermoelectric characteristics have been widely used in integrated electronic systems. Thermal rectification has important potential applications in semiconductor devices such as thermal management improvement of electronics and energy saving. The thermal conductivities and thermal rectifications of silicon devices with sets of triangular holes are investigated by nonequilibrium molecular dynamic (NEMD) simulations. The influences of the dimension and angle of the distributed triangular-shaped holes are investigated. The results indicate that the phonon scattering on the side and base of the right-angled triangular holes are quite different, which causes the thermal rectification. The thermal rectification effect is strengthened with the increase of the triangle dimension. However, the variations of the triangular angle have little effect on the thermal conductivities of the silicon device. Besides, the phonon spectral energy density along the frequency axis of the silicon system is given to explain the mechanism behind the rectification phenomenon. Based on the present simulation results, a possible design strategy is proposed for developing highly efficient thermoelectric devices. [ABSTRACT FROM AUTHOR]

Different from both finite‐time control (where the settling time depends on the initial condition) and fixed‐time control (whose settling time is subject to an upper bound but varies due to uncertainties and nonlinearities), the prescribed‐time control achieves regulation in prescribed finite time, even under uncertain nonlinearities. This article investigates the prescribed‐time regulation problem for a class of cascaded systems with integral form and control input constraints. The establishment of prescribed‐time property consists of the prescribed‐time regulation controller and prescribed‐time explicit reference governor (PT‐ERG), both of which satisfy the prespecified time requirement. For an elegant implementation, the feasibility for the separate design of controller and governor is guaranteed through a developed prescribed‐time cascaded stable theory. For the prescribed‐time controller, the proposed smooth time‐varying controller provides the prescribed‐time convergence based on a residual‐time‐dependent scaling transformation. For the PT‐ERG dealing with the control input constraints, a reference trajectory with a fixed minimum convergence rate provides an elegant compromise between performance and constraints which keeps the constraint satisfied and tracking errors in an invariant set. Both theoretical analysis and numerical simulations verify the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

Underwater discharge sound sources are widely utilized. The acoustic signals generated by underwater discharge consist of shock waves and bubble pulsations. The shock wave is a major component of underwater discharge sound sources and is worthy of further study. The minimum-phase cepstrum method is selected to separate the shock wave, and a customized experiment is designed to determine the optimal parameters of this method. The mixed shock wave bubble signal and single shock wave signal are simulated and fitted and are transmitted and received in the anechoic pool, respectively. Different parameters are used to process the signals, and the optimal parameters are selected by comparing the separation results. To verify the validity of the method, the shock waves generated with the same electrode and circuit parameters in the anechoic pool and non-anechoic pool are separated and compared. Experimental results show that this shock wave separation method exhibits significant performance. This method of shock wave separation is of service to the research of underwater discharge acoustic sources. [ABSTRACT FROM AUTHOR]

We present a comprehensive photometric and spectroscopic analysis of the short-period (∼5.32 h) and low-mass eclipsing binary TMTSJ0803 discovered by Tsinghua-Ma Huateng Telescope for Survey (TMTS). By fitting the light curves and radial velocity data with the Wilson–Devinney code, we find that the binary is composed of two late spotted active M dwarfs below the fully convective boundary. This is supported by the discovery of a significant Balmer emission lines in the LAMOST spectrum and prominent coronal X-ray emission. In comparison with the typical luminosity of rapidly rotating fully convective stars, the much brighter X-ray luminosity (L X/ L bol = 0.0159 ± 0.0059) suggests the stellar magnetic activity of fully convective stars could be enhanced in such a close binary system. Given the metallicity of [M/H] = − 0.35 dex as inferred from the LAMOST spectrum, we measure the masses and radii of both stars to be M 1 = 0.169 ± 0.010 M⊙, M 2 = 0.162 ± 0.016 M⊙, R 1 = 0.170 ± 0.006 R⊙, and R 2 = 0.156 ± 0.006 R⊙, respectively. Based on the luminosity ratio from the light-curve modelling, the effective temperatures of two components are also estimated. In comparison with the stellar evolution models, the radii, and effective temperatures of two components are all below the isochrones. The radius deflation might be mainly biased by a small radial velocity (RV) data or (and) a simple correction on RVs, while the discrepancy in effective temperature might be due to the enhanced magnetic activity in this binary. [ABSTRACT FROM AUTHOR]

Paraventricular thalamus (PVT) plays important roles in the regulation of emotion and motivation through connecting many brain structures including the midbrain and the limbic system. Although acetylcholine (ACh) neurons of the midbrain were reported to send projections to PVT, little is known about how cholinergic signaling regulates PVT neurons. Here, we used both RNAscope and slice patch‐clamp recordings to characterize cholinergic receptor expression and ACh modulation of PVT neurons in mice. We found ACh excited a majority of anterior PVT (aPVT) neurons but predominantly inhibited posterior PVT (pPVT) neurons. Compared to pPVT with more inhibitory M2 receptors, aPVT expressed higher levels of all excitatory receptor subtypes including nicotinic α4, α7, and muscarinic M1 and M3. The ACh‐induced excitation was mimicked by nicotine and antagonized by selective blockers for α4β2 and α7 nicotinic ACh receptor (nAChR) subtypes as well as selective antagonists for M1 and M3 muscarinic ACh receptors (mAChR). The ACh‐induced inhibition was attenuated by selective M2 and M4 mAChR receptor antagonists. Furthermore, we found ACh increased the frequency of excitatory postsynaptic currents (EPSCs) on a majority of aPVT neurons but decreased EPSC frequency on a larger number of pPVT neurons. In addition, ACh caused an acute increase followed by a lasting reduction in inhibitory postsynaptic currents (IPSCs) on PVT neurons of both subregions. Together, these data suggest that multiple AChR subtypes coordinate a differential modulation of ACh on aPVT and pPVT neurons. [ABSTRACT FROM AUTHOR]

Background: Nonspecific liver uptake of nanomaterials after intravenous injection has hindered nanomedicine for clinical translation. However, nanomaterials' propensity for liver distribution might enable their use in hepatic ischemia–reperfusion injury (IRI) repair. During hepatic IRI, reactive oxygen species (ROS) are generated and the fifth component of complement (C5a) is activated. In addition, C5a is confirmed to exacerbate the vicious cycle of oxidative stress and inflammatory damage. For these reasons, we have investigated the development of nanomaterials with liver uptake to scavenge ROS and block C5a for hepatic IRI repair. Results: To achieve this goal, a traditional nanoantioxidant of nanoceria was surface conjugated with the anti-C5a aptamers (Ceria@Apt) to scavenge the ROS and reduce C5a-mediated inflammation. High uptake of Ceria@Apt in the liver was confirmed by preclinical positron emission tomography (PET) imaging. The clinical symptoms of hepatic IRI were effectively alleviated by Ceria@Apt with ROS scavenging and C5a blocking in mice model. The released pro-inflammatory cytokines were significantly reduced, and subsequent inflammatory reaction involved in the liver was inhibited. Conclusions: The synthesized Ceria@Apt has great potential of medical application in hepatic IRI repair, which could also be applied for other ischemic-related diseases. [ABSTRACT FROM AUTHOR]

This is an incompressible numerical study of the hydrodynamics and heat transfer characteristics of Taylor flow in vertical oil and gas pipelines under constant heat flux using the Volume-of-fluid (VOF) method in ANSYS Fluent, covering a wide range of Re(0.22 ≤ Re ≤ 800) and Ca(0.0075 ≤ Ca ≤ 0.35). Nusselt number (Nu) correlations were used to examine the heat transfer characteristics based on a set of flow parameters. A comparison of the predictions of the void fraction, average velocity, pressure drop and the mean Nusselt number was made with available experimental observations, with most of the experimental data falling within 15.540% of the current study. The bubble increases in length with increasing capillary number and the wall of the tube at the confines of the gas phase leads to asymmetric and axisymmetric bubbles at low and high capillary numbers respectively. The transition region between the edge of the bubble and the film thickness increases with an equivalent increase in Ca and more evident at high Re. The study revealed that, Taylor flow plays a more significant role on the pressure drop increase and, provided the mechanisms and theoretical guidance for heat transfer characteristics in oil and gas pipelines. [ABSTRACT FROM AUTHOR]

The transition pattern and the initiation length are the core features of the oblique detonation wave. Two transition patterns have been widely studied. A new transition pattern is observed recently. However, the relationship between the new pattern and the former two patterns is not clear, which prevent the oblique detonation wave from the realistic application. Besides, what causes the new pattern is still unknown. In the current research, the new transition pattern is defined as 'local detachment' due to its unique features. Different nitrogen dilutions are utilized to obtain different detonation velocities. The effects of the nitrogen dilution on the Chapman-Jouguet velocity and the overdriven detonation velocity are discussed in detail. The features of different transition patterns are compared. The local detachment is featured by an upstream propagation of the wave front and a jump of the initiation location. Although the local detachment can bring forward the initiation location significantly, it is suggested to avoid it during designing the engine because the local high pressure can erode the combustor and leave the initiation location uncontrollable. The formation mechanism of the local detachment is discussed in detail. The local detachment is dominated by the ratio of detonation velocity to free stream velocity. When the ratio increases, the transition pattern changes as Smooth → Abrupt → Local detachment. This relationship is vital for predicting the local detachment of the oblique detonation wave. • It is suggested to avoid local detachment during designing the engine. • The relationship between the new pattern and the former two patterns is revealed. • The detonation velocity dominates D / V in when the nitrogen dilution changes. [ABSTRACT FROM AUTHOR]

State-based peridynamics for elasticity paves the way to bridge the local theory with the inherent capabilities of general elasticity with non-local effects. However, the original non-ordinary state-based peridynamics with correspondence materiel models suffers from high-frequency oscillations due to zero-energy mode instability. To address this issue, we start from the fundamental Lagrangian with the introduction of a constraint potential energy that minimizes the numerical error and suppresses the zero-energy mode oscillations. A stabilized non-ordinary state-based peridynamics is then derived from this constrained Lagrangian that forms an integral–differential–algebraic system. In specifics, the equation of motion for particles is described by integral-differential equations while the constraint suppressing the zero-energy mode instability is expressed as algebraic equations (zero-error constraint). An energy–momentum conserving implicit time-stepping scheme for this integral–differential–algebraic system is then derived. End-to-end 2D and 3D simulations, including scalar wave propagation, crack path, and large deformation problems, are presented to show that the proposed method is promising for these applications in terms of accurately capturing the crack path and large deformation, efficiently eliminating the numeral oscillations, conserving the total energy for long duration simulations, and preserving the zero-error constraint. • A TL-Peridynamics with stabilization that suppresses the zero-energy mode instability. • An energy–momentum conserving implicit time-stepping algorithm that allows long duration simulations. • Zero-error constraint preservation in the machine error (10−16). [ABSTRACT FROM AUTHOR]

• The effects of cracks on ignition delay time of energetic material are studied. • Peridynamic non-Fourier heat conduction numerical scheme is applied to the laser ignition model. • The effects of cracks are related to their own distribution and the energy absorbed by the material. The actual ignition process in the artillery barrel is complex, cracks in the energetic materials will inevitably appear due to the influence of various factors, but they are rarely considered in previous experiments and simulations. A laser ignition model of energetic materials considering insulating cracks is constructed. Peridynamic non-Fourier heat conduction numerical scheme is utilized to simulate the laser ignition process of energetic materials with cracks. The applicability of the peridynamic formulation is first verified by comparing the ignition delay time of crack-free energetic material with experimental results. The effects of cracks on ignition delay time in various cases are then investigated mechanistically via simulation results. The results show that cracks affect heat transfer leading to heat accumulation near the crack, which accelerates the temperature rise and shortens the ignition delay time. Moreover, laser power and crack distribution change the influence of cracks on heat transfer. This serves as a numerical reference for the research of the actual launch process in the barrel. [ABSTRACT FROM AUTHOR]

The heat transfer and hydrogen fuel flow characteristics in the novel fin structure for the branched-wavy cooling channel of the rocket engine combustion chamber where three different gap widths (wz = 0.4, 0.6, and 0.8 mm) and three different amplitudes were examined numerically. Nusselt number, heat wall temperature, pressure drop, and thermal stratification were studied using Ansys fluent to investigate how configuration, wavy amplitude, and transfer gap width influenced these variables. The findings show that the heat wall temperatures and the average Nusselt number for the original symmetric configuration are better than the parallel one. The modified symmetric wavy design results show that the secondary branch flow considerably enhances Nusselt numbers due to the promoted fluid mixing between neighboring channels; the average Nusselt number of the modified symmetric configuration channel (A = 0.3 mm) enhanced up to 28.23% compared to the original straight configuration when adopting transverse gaps of 0.8 mm. The modified configuration (amplitude of 0.1 mm with a 0.8 mm transfer gap) achieved the highest thermal performance factor, which was enhanced by 21% compared to the original wavy design. Modified symmetric designs can slightly reduce the pressure drop penalty by creating a transverse gap. • The Nusselt number of the modified symmetric configuration enhanced by 28.23%. • Adding the transverse gaps increased heat transfer and flow characteristics. • The proportional pressure drop decreases with an increasing transverse gap. [ABSTRACT FROM AUTHOR]

• A non-local heat transport model is developed based on Lagrangian particle method. • The formulation is consistent with the corresponding peridynamics in solid mechanics. • Good performance is shown in the case with sharp corners. • Thermal diffusion in the case with cracks is easily handled. A new Lagrangian non-local diffusion model, designed as a meshless particle simulation method, is proposed to predict the thermal response of solids involving discontinuous. The main idea is to understand the heat transfer process of solids via a Lagrangian treatment of a particle-discretized system, which provides a more general physical representation of the heat transfer process of solids. In contrast to the traditional differential model, the proposed mathematical model is expressed via an integral form, which can easily handle the case involving discontinuities. The spatial convergence studies show that the proposed model converges to its associated non-local solution while increasing the number of particles in a fixed cut-off radius; and it can reach the local exact solution when the cut-off radius is close to zero. The numerical examples not only verify that the proposed diffusion model converges to the continuum heat conduction model, but also show the capability of its application to heat transfer problems involving discontinuities. In particular, the computational performance of the proposed non-local thermal model is also demonstrated its computational performance in the case with practical crack propagation in a two-dimensional plate. In addition, the specific comparison between the proposed method and the well-developed peridynamics approach for heat conduction problems is carefully described with rigor via mathematical proofs and numerical results. Specifically, the proposed model is shown to be a variation of the corresponding peridynamic-type thermal diffusion model. This model not only has a formulation consistent with that of peridynamics in solid mechanics but also shows a better performance in the case with sharp corners than that of the peridynamic diffusion in [1]. [ABSTRACT FROM AUTHOR]

The Oblique Detonation Wave Engine is expected to propel the aircraft to hypersonic speeds. Currently available studies are mainly focused on the initiation characteristics of the oblique detonation wave on a straight wedge. The control method is of great importance for a better thrust performance. However, there lacks the trigger location control method of the oblique detonation wave. In the current research, a co-flow hot jet is utilized to initiate the oblique detonation wave with an initiation length shorter than that on a straight wedge. The performance of the co-flow hot jet under different inflow pressures is discussed in detail. The mechanism for the initiation of the oblique detonation wave by the co-flow hot jet is revealed. It is found that the key for the initiation by the co-flow hot jet is an underexpanded jet, which is featured by a first jet shock wave, a second jet shock wave, an expansion fan, and an intercepting shock wave. The first and second jet shock waves are observed for the first time in the research of the oblique detonation wave. The strength of the first and second jet shock waves is higher than that of the leading shock wave, reducing the initiation length of the oblique detonation wave greatly. This investigation reveals the initiation mechanism of the oblique detonation wave by the co-flow hot jet, which is of great importance for its application in the Oblique Detonation Wave Engine. • A co-flow hot jet is utilized to initiate the oblique detonation wave. • The key to the initiation by the co-flow hot jet is an underexpanded jet. • The performance of the co-flow hot jet under different inflow pressures is discussed in detail. [ABSTRACT FROM AUTHOR]

A nondestructive and rapid method has been put forward to grade tobacco leaves in the paper. The method is based on a combination of a hand-held near-infrared spectrometer and a particle swarm optimization-extreme learning machine algorithm. Firstly, the spectral data of the training samples are collected directly from the tobacco leaves nondestructively by using a hand-held near infrared spectrometer without any pretreatment. Secondly, the training models of different classes are built using particle swarm optimization-extreme learning machine algorithm. Finally, the classes of test samples can be predicted by using the developed models. Besides, the classification results of particle swarm optimization-extreme learning machine algorithm are also compared with that of the traditional linear discriminant analysis, support vector machine, and extreme learning machine algorithms, respectively. The experimental results show the classification accuracy of the particle swarm optimization-extreme learning machine algorithm is comparable after the parameter optimization. It indicates that the interplay between the hand-held near-infrared spectroscopy technology and particle swarm optimization-extreme learning machine algorithm will provide a novel classification method for grading tobacco leaves in the purchasing process on the spot. [ABSTRACT FROM AUTHOR]

Higher-silane related reactive species (HSRS) is considered as a key factor in increasing the degree of photo-induced degradation, which is a serious problem for hydrogenated amorphous silicon (a-Si:H) film. Dilution gases (H2, He, Ar) are used to control the generation of HSRS. A global model for SiH4-containing discharge is developed to investigate the concentration of HSRS. The model calculations are compared with the available measurements, presenting a reasonable agreement. Increasing pressure contributes to more power loss via volumetric processes, which brings about the decline in the electron density and temperature with the same absorbed power. The average electronegativity rises with the silane content or pressure log-linearly, but decreases with the power log-linearly. As the main precursor of the anion formation, is the starting point for the formation of large silyl anions (). The HSRS density rises first and then falls with the increase of the absorbed power, which can be explained by the decomposition of SiH4. The dilution of H2 promotes the generation of H atomics, enhancing the production of SiH2 with abstraction reaction (H + SiH3 ⇒ H2 + SiH2). However, due to the declined content of SiH4, the insertion reaction (SiH2 + SiH4 ⇒ Si2H6) is inhibited. A higher Ar fraction results in more total ionization and a larger ion density. Due to the high threshold energies of He for both excitation and ionization, the dilution of He does not contribute much to the variation of the neutral radical density. [ABSTRACT FROM AUTHOR]

Due to the single-side heating on the rectangular channel, the coolant faces a serious thermal stratification problem, and thus the heat transfer performance is reduced. To effectively improve flow and heat transfer characteristics, and weaken nonuniform distribution problem, a new cooling structure with combining fin and spherical convexity is built in this paper. The study results indicate that the new structure effectively reduced the maximum heat wall temperature, and weakened the fluid nonuniform distribution problem. Comparing with smooth channel and spherical convexity structure, the maximum temperature is decreased by 18.4% and 10.3%, and temperature nonuniform index is decreased by 25.1% and 20.8%. In addition, as the higher fluid temperature means the higher specific heat capacity, the new structure made full use of the heat sink of hydrogen, making the more heat can be quickly taken away from the heat wall. The thermal stratification phenomenon can be obviously weakened. [ABSTRACT FROM AUTHOR]

The mechanism affecting the saturation frequency of plasma synthetic jet actuators is still unclear, which has led to the great hindrance of the application of plasma synthetic jet actuators on supersonic aircraft. Discharge parameters affecting the saturation frequency of plasma synthetic jet actuator and the average Helmholtz frequency are analyzed based on a novel coupling model in this paper. The model couples the phenomenological energy source term model with the mechano-acoustical analogy model. The Helmholtz frequency at each moment during the formation of the synthetic jet can be calculated. The effects of the electrical energy, the discharge duration and the instantaneous discharge power on the formation of the synthetic jet in a single discharge are investigated. The results show that the average Helmholtz frequency could not be used to evaluate the saturation frequency of the plasma synthetic jet actuator because they have different trends as electrical energy increases. The average Helmholtz frequency increases linearly with the increase of electrical energy, while the saturation frequency decreases in power function. The discharge duration on the microsecond scale and the instantaneous discharge power have little effect on the saturation frequency. [ABSTRACT FROM AUTHOR]

We conducted in situ geochemical (major-, trace-element and Nd isotope compositions) analyses on apatite, together with whole-rock geochemistry from gabbro, granodiorite and granite in the Cretaceous Pingtan intrusive complex (SE China), aiming to investigate the roles of magmatic evolution and post-crystallization hydrothermal activity during its formation. Regardless of limited range in initial Nd isotopes ranges in both bulk rock [ɛNd(t) = − 2.0 to − 0.4] and associated apatite [ɛNd(t) = − 3.8 to − 0.4] from the Pingtan igneous complex, the apatite shows wide compositional and textural variations from gabbro to granite. Apatite from the gabbro (Group 1) displays a zoning structure characterized by increasing F and Sr but decreasing Cl and LREE from the core to rim. The increase of Sr from the core to rim is attributed to plagioclase accumulation, and the decreases of LREE and Cl from the core to rim is caused by post-crystallization hydrothermal activity. The high Cl content in the primitive Group 1 apatite further suggests derivation of the mafic magma from a mantle wedge metasomatized by Cl-rich sediment. In contrast, apatite from the granite (Group 2) has the lowest Cl and Sr but the highest F and Yb contents, which can be further divided into two subgroups of Group 2A and 2B based on texture and composition. Group 2A apatite shows homogenous composition with trace elements similar to apatite from I-type granite. The positive correlation between Sr and Eu/Eu* indicates that crystallization of Group 2A apatite is co-precipitated with a feldspar-dominated fractionation. However, Group 2B apatite contains mineral inclusion of monazite and has the highest U content and F/Cl ratio, resembling apatite from S-type or highly fractionated I-type granite. These features are consistent with the influence of post-crystallization hydrothermal activity. Apatite from the granodiorite (Group 3) has an intermediate composition between Group 1 and 2A apatite and shows a homogenous texture with trace element features similar to that from I-type granite. Group 3 apatite defined a negative correlation of Sr with La/Yb, which is attributed to fractional crystallization of hornblende and plagioclase. The geochemistry of apatite indicates that the gabbro and granitic rocks of the Pingtan intrusive complex were, respectively, derived from the mantle and crustal sources with similar ɛNd(t) values. Our study, therefore, demonstrates that apatite geochemistry has a potential to monitor the magma source, magmatic evolution and post-crystallization fluid activity of an igneous complex. [ABSTRACT FROM AUTHOR]