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Rapeseed harvest cutting tools have been confined to large vibrations, entanglement, wear, and low efficiency. In this study, gas jet cutting was proposed for rapeseed stems using abrasive particles. This technique aimed to achieve the noncontact cutting between the machinery and the rapeseed, thereby ensuring efficient and low-consumption harvesting of rapeseed. The dynamic jet cutting of rapeseed stems was simulated using the smooth particle hydrodynamics-finite element method (SPH-FEM). The energy transfer between gas and solid phases was obtained for the dynamic behavior of the jet cutting. A test system was constructed to experimentally verify the jet cutting. The research results indicate that the maximum speeds of the airflow and abrasive particles were 741 and 411 m/s, respectively, when using a high-speed nozzle with a 4 mm diameter at a jet pressure of 20 MPa. Approximately 95% of the acceleration occurred in the throat and expansion sections. The external flow field of the nozzle exhibited a fluctuating pattern with the first decreasing and then increasing. The greater the jet pressure was, the more pronounced the velocity contraction and expansion fluctuations were. The jet beam primarily accelerated during gas expansion-contraction-expansion, thus converting the pressure into the kinetic energy of the jet beam. Once the inlet pressure increased from 3-10 MPa, the acceleration efficiency of the abrasive particles decreased from 31% to 11%. When the pressure exceeded 3 MPa, there was a further increase in the jet pressure, leading to a significant reduction in the efficiency of converting jet beam pressure energy to kinetic energy. At the same time, the maximum speed of abrasive particles with a diameter of 0.1 mm was 19% higher than that with a diameter of 0.3 mm. The larger the diameter of the abrasive particles were, the greater the cutting kinetic energy they obtained. Among them, 0.3 mm diameter abrasive particles exhibited the highest cutting kinetic energy, followed by 0.2 mm, and then 0.1 mm diameter. The minimum jet pressure of 0.4 MPa was required for the cutting rapeseed stems, with a lateral movement speed of 5 mm/s. Therefore, the stem was cut through in a single pass at a target distance of 10 mm. Once the lateral movement speed exceeded 5 mm/s, there was no cutting through in a single pass. When the jet nozzle was positioned 5 mm away from the target and the lateral movement speed was 5 mm/s, the minimum volume of cutting erosion was achieved in the incision widths ranging from 1 to 6 mm. The findings can also be applied to the cutting of similar crop stems. Theoretical and technical support can also be offered for the non-contact high-efficiency cutting equipment in modern agriculture. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to further improve the drilling performance of polycrystalline diamond composite (PDC) bit in deep hard formation and restrain the occurrence of the viscous sliding phenomenon, a circular saw-shaped imitation tooth based on the bionic similarity principle and saw-shaped tooth structure was proposed based on the mole claw toe as the prototype. Based on elastic-plastic mechanics and finite element nonlinear dynamics theory, a simulation model of rock breaking of cutter and bit was established. The rock-breaking process of the serrated tooth and circular serrated tooth was compared, and the whole drilling process of the two kinds of serrated bit was compared. The results show that the circular arc sawing teeth are mainly used to break rock by plow and shovel, which can concentrate the load, reach the yield limit of rock more easily, and make the rock more easily broken by tensile stress. The cutting force is reduced by 15.8% compared with the sawing teeth, and the efficiency is higher. The bit with a circular saw bionic PDC teeth can break more rock, improve the footage significantly, and suffer less torque, which can effectively solve the viscous sliding of the bit. The research results have important reference values for the design of high-performance drill bits in China. [ABSTRACT FROM AUTHOR]

Grapevine picking-up machinery is a high demand in the open-field grape-producing regions of northern China during spring. In this study, the grapevine picking-up mechanism was proposed for the lifting operation using a crank-rocker mechanism. The mechanism was mainly consisting of a frame, crank rocker structure, pushing bar, picking bar, spring, and vine fender. Grapevines were lifted from the ground to the given angle with a simple and reliable structure. The structure of crank rocker was used to constrain the movement trajectory of the picking bar. The pushing bar was used to gather the grapevines, and then the picking bar was lifted them. MATLAB software was also utilized to optimize the parameters of the trajectory curve. An optimal set of structural parameters was achieved for the picking bar. The length of the crank was 160 mm, the length of the link-rod was 480 mm, the length of the rocker was 340 mm, and the length of the base frame was 600 mm. The endpoint coordinates of picking bar were relative to the uBv coordinate system as (1 070 mm, -250 mm). According to multi-flexible-body dynamics (MFBD) simulation, the finite element (FE) flexible body model was established for the grapevines and picking-up operation. A Box-Behnken simulation experiment was designed to analyze the impact of three parameters (forward speed, spring preload force, and crank rotational speed) on the grapevine picking-up through the software RecurDyn. Regression significance analysis of the experimental data was conducted using Design-Expert software, with the average angle and the coefficient of angle variation as the evaluation indices. The results showed that all three test factors shared a significant effect on the average angle, while the forward speed posed a significant effect on the coefficient of angle variation. Among the interaction factors, the spring preload force and the crank rotation speed had a significant impact on the average angle, while the spring preload force and the crank rotational speed had a significant impact on the coefficient of angle variation. Among the quadratic factors, only the square of the forward speed and the crank rotational speed had a significant effect on the coefficient of angle variation, while the rest factors had no significant effect. The maximum average angle and the minimum coefficient of angle variation were obtained after optimization. Consequently, the best combination of working parameter was determined for the machine: the forward speed was 0.2 m/s, spring preload force was 128 N, and crank rotation speed was 67 r/min. As such, the average angle of grapevines was 40.6° in RecurDyn, and the coefficient of angle variation was 6.0%. Finally, the prototype was manufactured to conduct the soil bin tests. There was the essentially consistent data with the optimization. The relative error between soil bin tests and simulation was 6.4%, and the mean of the coefficient of angle variation was 14.8%, fully meeting the operational requirements for picking up grapevines. This finding can be expected to serve as a strong reference in the integrated machines for grapevine lifting and tying. [ABSTRACT FROM AUTHOR]

Aiming at the problems of high charging voltage of the shock chip detonator in the in-line safety detonation system and it is difficult to meet the requirements of conventional weapons, a multi-functional electric explosion detonation and testing instrument was designed, an explosion foil model was established for simulation, and a low-voltage ignition environment was carried out. The explosion voltage and explosion current test experiments of three explosion foils with the same shape and different materials were used to observe the electric explosion process by using a high-speed camera and an electron microscope. Higher at 1 000 V, it can reach 28. 6%, the peak power is larger, and the electric explosion performance is better. Taking low-voltage ignition as the test condition, the detonating instrument verified the electric explosion characteristics of the explosion foils of different materials, which provided a certain reference value for the research on the electric explosion performance of the shock sheet detonator with low energy. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective Analyzing the applicability of pipeline simulation technology in energy measurement, and examine the deviation between simulation calculation results and actual pipeline measurement values. Methods Using a closed natural gas pipeline network with multiple gas sources will be as an example, a simulation model with functions for natural gas heat generation, pressure, and flow calculation was established. This model is based on the theoretical foundation of pipeline network simulation for energy measurement. Results The deviation between the simulation results of heat generation and the calculated values of the on-site chromatographic analyzer is within 0.3%, which meets the requirements of the maximum allowable error of assigned heat generation in GB/T 18603—2023 Technical requirement of measuring systems for natural gas. The deviation between the pressure simulation calculation result and the recorded value of the on-site pressure transmitter is within 1.0%, and the deviation between the flow simulation calculation result and the measured value of the on-site flow meter is within 2.0%. Conclusions The energy measurement technology based on pipeline simulation is a feasible method for assigning heat generation values to complex multi-gas source pipelines. This method can also be used for real-time tracking or verification of pipeline pressure, flow rate, and natural gas pipeline inventory. [ABSTRACT FROM AUTHOR]

The aeroengine control system is a safety critical system for aeroengine, crucial for generating reliable thrust or power within the entire flight envelope of the engine. This paper presents the evolution of the aeroengine control system, summarizes and analyzes the development of three key system-level technologies. including architecture design, control law design, and fault diagnosis and condition monitoring design, as well as simulation enabling technologies. The discussion on the applicability of these technologies in engineering is then conducted. The prospects for future development directions and key research areas are finally explored, providing a valuable reference for the design of next generation aeroengine control systems. [ABSTRACT FROM AUTHOR]

The improvement of computing power provides a support for finite element simulation analysis, which can solve more complex structures and nonlinear problems more efficiently. In this study, based on the finite element simulation analysis technology, the complex mechanical properties of Mn-Cu alloy are simulated. Prony series constitutive model and parallel rheological constitutive model are respectively adopted to simulate the stress relaxation test of Mn-Cu alloy under different deformation conditions. The stress relaxation experimental data are extracted and converted into the corresponding model parameters and the finite element simulation calculation is carried out. The simulation model parameters which can accurately describe the nonlinear mechanical properties of Mn-Cu alloy are obtained. By comparing the simulation and experimental results, it is concluded that the parallel rheological framework can more accurately characterize the stress relaxation behavior of Mn-Cu alloy. Under different initial strain conditions, the relative error of the simulation results and the test results under corresponding working conditions is less than 1%. Compared with Prony series constitutive model, parallel rheological framework is more suitable for the simulation of Mn-Cu alloy under complex working conditions. [ABSTRACT FROM AUTHOR]

Copyright of Technology of Water Treatment is the property of Technology of Water Treatment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Taking into account the stability of spinal fixation, the preferred approach for lateral lumbar interbody fusion is commonly the utilization of posterior bilateral pedicle screws, typically performed in two stages. An alternative method involving the posterior approach of unilateral fixation using lateral vertebral nail rods in the lateral decubitus position has shown potential for enhanced mechanical stability. This technique also offers additional advantages such as reduced operation time, lowered risks, and decreased costs, making it a promising area for further investigation. OBJECTIVE: To compare the biomechanical effect of lateral lumbar interbody fusion with four different types of posterior instruments. METHODS: A validated L3-5 finite element model was modified to simulate four different types of lateral lumbar interbody fusion: Model A: posterior bilateral pedicle screw fixation; Model B: posterior unilateral pedicle screw fixation; Model C: lateral bilateral screw fixation; Model D: lateral unilateral screw fixation. The stability in the range of physiological motion, and the stress difference of screw fixation and interbody fusion apparatus were compared among the models. RESULTS AND CONCLUSION: (1) When compared with the intact model, all reconstructive models displayed decreased motion range at L4-5. Model A had a more obvious range of motion decline. (2) In the flexion, lateral flexion and axial rotation, the differences between the peak stress of the lateral screw fixation and the peak stress of the posterior screw fixation were more than 67.74 MPa, 80.10 MPa and 43.95 MPa, respectively. (3) In terms of internal fixed stress distribution in different reconstructed models, the stress distribution of Model A and Model B screws was mainly concentrated in the body of the pedicle screw, while the peak stress of Model C and Model D screws was mainly concentrated in the tail of the screw. (4) It is suggested that Model A could obtain the best stability and reduce the risk of cage sinking and displacement. Model B could also provide better stability, and could be a choice for lateral fusion on the premise of ensuring stability and fixation. (5) Besides, Model C could achieve the same effect as Model D when the lateral road screw was selected. However, patients with lumbar instability should be cautious to choose unilateral lateral internal fixation, and excessive extension should be avoided to reduce the possibility of screw loosening and fixation fatigue. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To improve the existing temperature field control technology for mass concrete and to apply temperature control measures more effectively using inhibitors while reducing construction cost, a regulating model was proposed. This model was based on an adiabatic temperature rise equation for concrete mixed with inhibitors of different delayed heat release times. The distribution of temperature fields for mass concrete subjected to different temperature control measures involving inhibition was investigated using the model. Specifically, under the working conditions of delayed heat release of 0 ~ 3 d, the internal temperature peak and temperature difference between the inner and outer surfaces of the mass concrete decrease continuously as the delayed heat release time increases. However, under the working conditions of delayed heat release of 5 ~ 10 d, heat accumulation in multi-layer poured concrete occurs due to the prolonged delayed heat release time. A three-day inhibition of heat release meets the temperature control objectives, For a oneday inhibition of heat release, the temperature control objectives are achieved by reducing the initial temperature of the concrete in the mold by 1 ~ 2 ℃ . In conclusion, this research introduces a new concept and method for regulating the temperature field of mass concrete. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

MOX (mixed oxide) fuel plays a positive role in promoting sustainable development in nuclear energy. The quantitative determination of plutonium in mixed MOX fuel is also essential to nuclear security and safeguards. In this regard，neutron multiplicity measurement methods serve as crucial non-destructive testing techniques and play a vital role in quantitatively detecting plutonium in MOX fuel. In order to study the factors that influence the quantification process of plutonium，enhance measurement accuracy，and streamline the process，this study develops a comprehensive and specific simulation system for the multiplicity-based plutonium quantification method in MOX fuel. Based on the AWCC device as the basic model (simulation model with a detection efficiency of 23.89% and a die-away time of 45.42 μs)，the combination of MCNP and MATLAB software is utilized to recombine the detector capture times of fission neutrons and (α，n) neutrons obtained from MCNP software with the particle emission time series obtained by MATLAB sampling，forming a complete pulse time series. After receiving the multiplicity moments of fission neutrons in MOX fuel (vs1=2.157，vs2=3.808，vs3=5.283，vi1=2.855，vi2=6.953，vi3=13.899)，simulated pulse sequence acquisition，multiplicity analysis，and quantitative calculation are performed on four samples with different shapes and sizes. Each sample is measured for 300 s with a pre-delay time of 3 μs，a gate width of 54 μs，a long delay of 2 ms，and repeated three time’s measurements. Additionally，the simulated quantitative calculation results 240Pu are compared with the set values. The results indicate that the mass of 240Pu and the α-value obtained through simulated pulse analysis meet the requirement of less than 5% relative error compared to the actual input values. This work provides technical support for data interpretation in the quantitative measurement of plutonium in MOX fuel.

[Introduction] The inertial electrostatic confinement (IEC) fusion facility is a small fusion device. This paper aims to solve the problems of IEC fusion devices, such as the cathode melting, the very low Q value, and so on. [Method] This paper first analyzed the reasons for these problems, and then a new type of inner ion source IEC fusion was proposed to decrease the ion loss during the confinement process, solve the cathode melting, and increase the vacuum in the device and the Q value. [Result] At last, the improvement of neutron yield is qualitatively analyzed through the estimation, the very complex ion motion inside the fusion device is simulated through numerical simulation calculation, and anisotropic ion motion trajectories are obtained. [Conclusion] Based on estimation and numerical simulation results, the feasibility of the IEC with an inner ion source is confirmed, which can solve the problems of cathode melting and low Q value.

[Objective] Simulating the change of runoff and sediment changes in the watershed under the influence of land use and climate in the future is conducive to making suitable management plans. [Methods] Based on land use and meteorological data, combined with CMIP6 climate model data, PLUS model and SWAT model, the temporal and spatial changes of land use and runoff and sediment under different climate scenarios in 2030 were quantitatively simulated. [Results] (1) The SWAT model exhibited good accuracy in monthly scale in simulation of Minjiang River Basin, in which the R2 and NSE (Nash-Sutcliffe Efficiency) ranged from 0.80 to 0.95 and 0.75 to 0.91, respectively. The R2 and NSE ranged from 0.75 to 0.98 and 0.64 to 0.94 respectively. (2) Using the land use data of 2020 to evaluate the accuracy of the PLUS model, the Kappa coefficient was 0.77, and the simulated construction land and cultivated land in the Minjiang River Basin in 2030 would increase by 325.64 km2 and 1 157.51 km2, respectively. (3) Under the SSP2-4.5 and SSP5-8.5 scenarios, the average precipitation in 2025—2035 would increase by 0.15% and 2.18%, and the average annual temperature would increase by 0.23 and 0.62 ℃, respectively. (4) In the low carbon and high carbon scenarios, only land use change led to an increase of 0.08% and 0.07% in annual mean runoff, and an increase of 0.24% and decreased of 0.05% in annual mean sediment transport, respectively, compared with the baseline period. Compared with the baseline period, the mean annual runoff decreased by 4.76% and 4.11%, and the mean annual sediment transport increased by 18.12% and 0.13%, respectively. The combined effects of land use and climate resulted in a decrease of 4.57% and 3.93% in annual average runoff and an increase of 18.28% and 0.33% in annual average sediment transport compared with the base period, respectively. (5) Under the scenario of future climate and land use comprehensive change, the areas with higher and larger increase in surface runoff and sediment yield were concentrated in the northwestern of the basin centered on Shaowu City in Nanping and the southwest of the basin centered on Jiangle County in Sanming. [Conclusion] These research results provide some reference for the reasonable development and construction of Minjiang River basin in the future.

[Objective] This paper seeks to address shortcomings in the conventional structural design of welding torch nozzles, such as prolonged development cycles, high costs, and uncertainty regarding the efficacy of shielding gas fow field protection. [Methods] The fuid dynamics computational software Fluent was utilized for numerical simulations, concentrating on critical parameters like shielding gas fow rates, welding torch nozzle structures, and nozzle-to-bevel spacings. The simulation results were subsequently verified and analyzed through gas dyeing experiments and practical welding operations. [Results] In the gas metal arc welding(GMAW) process context involving narrowgap bevels, a shielding gas fow rate of 20 L/min yielded effective protection to pipes. The conical nozzle and the fat conical nozzle presented ideal results in which the fat conical nozzle structure helped the shielding gas fow field obtain minimal conicity and straighter fow, fostering stable welding conditions by efficiently resisting crosswind disturbances at lower fow rates. Ensuring a nozzle-to-bevel spacing of less than 15 mm produced a shielding gas fow field with enhanced protection. The subsequent gas dyeing experiment and welding operations mirrored the simulation results on the fow field and welding performance of the conical nozzle and fat conical nozzle, affirming the feasibility of simulation methods for optimizing shielding gas fow fields. [Conclusion] The study findings showcase the effectiveness of fuid dynamic computation simulation technology in optimizing the structural design of welding torch nozzles and accelerating the development cycles, significantly improving the utilization efficiency of shielding gas in the GMAW welding process with narrow-gap bevels, and enhancing the stability of welding quality.By emphasizing the important role of simulation in welding process improvement, this paper offers new insights and technical references for the structural design of welding torch nozzles and the regulation of shielding gas fow fields.

Xinjiang is an important area linking China with Central Asia and Europe, and is a vital land pivot point of China's "One Belt, One Road". As the number of flights increases year by year, the control pressure in Xinjiang control area increases year by year, and the problems of uneven load distribution and increasing conflict points in the sector are becoming more and more serious. In this paper, the traffic growth of the Xinjiang control region in 2035is predicted in the light of the development requirements of China's "One Belt, One Road" and "Air Silk Road", and then a capacity assessment of the current sector classification scheme is conducted based on the controllers' workload. Finally, computer simulation technology is used to evaluate the sector designation scheme in 2035. The results show that the new sector division can effectively reduce peak day traffic and peak hour traffic. Through reasonable division of sectors with high controller load, the control pressure has also been significantly alleviated.

Based on the software Fluent, we simulate the mixing process of twin-screw belt agitator. Using the multi-functional stirring experimental platform, the rationality of the simulation model is verified by the test of the power consumption. Combining with examples, the effects of boundary gap, screw belt diameter and pitch on the stirring characteristics are analyzed. For the hard spots of mixing effect and efficiency (economic power consumption), we proposed the values of power consumption factor and axial power factor to characterize the energy utilization effect and overall mixing effect of high-viscosity fluid. Take this as a basis, the key geometric parameters of the screw agitator are optimized. The simulation results of the example show that when the screw belt diameter is 1 200 mm, which reaches 0.8 times of the tank diameter, the maximum of the axial power consumption factor is 0.232 6 s, indicating that the axial fluid macro mixing effect is the best; when the pitch is 1 350 mm, which equals to the diameter of the blade (spiral rising angle is 45°), the maximum of the axial power consumption factor is 0.180 6 s, indicating that the macroscopic mixing effect of axial fluid is the best, with the decrease of boundary gap, the peak value of the total velocity of the tank wall increases, indicating that the anti-adhesion effect is enhanced and the thermal boundary layer on the inside of the tank wall is thinned. [ABSTRACT FROM AUTHOR]

This study aims to accurately predict the distribution of heat and moisture in corn piles during ventilated drying. Taking the corn pile within the silo as the subject, the heat and moisture transfer model was established to simulate the ventilated drying of the corn. A systematic investigation was also implemented to clarify the suitable ventilation conditions. The heat was then released by corn respiration, according to the local thermal non-equilibrium equation. The experiment was carried out on the integrated silo of grain drying and storage using COMSOL Multiphysics. An experiment was conducted on the corn pile in the silo, with specific conditions, including air velocity, air temperature and relative humidity. The simulation was focused on the moisture content, temperature distribution of corn and temperature, humidity distribution of air in the corn pile. The results showed that the heat and moisture transfer model effectively simulated the ventilated drying of corn pile in the silo. The relative errors between the simulated and experimental values of corn temperature and moisture content at four points within the silo ranged from 1.4%-12.1% and 0.3%-14.5%, and the average relative errors were 4.8% and 6.5%, respectively. Similarly, the relative errors between the simulated and experimental values of air temperature and air relative humidity within the silo were 0.7%-15.1% and1.3%-15.4%, respectively, and the average relative errors were 5.5% and 8.9%, respectively. Notably, there was the unevenness of corn in the silo at the initial stage of corn ventilation. The inner layer of corn was experienced the higher rates of heating and drying. The higher air velocity resulted in the increased airflow per unit time. For example, the maximum difference in the moisture content reached 0.03 g/g along the ventilation direction. However, the heating and drying rates of corn were gradually reduced, as the ventilation progressed, leading to a decrease in the unevenness of corn pile. The equilibrium temperature of corn was then reached after 25 h, while the approximate equilibrium moisture content was reached after 60 h. The air temperature rose rapidly within the first hour of ventilation, followed by a slow increase to nearly 25 ℃. The humidity initially increased and then decreased, where the rate of decline was gradually slowed down until equilibrium was reached. The cloud map analysis revealed that there was a significant difference in the area near the silo wall and the overall, indicating the need to optimize the silo and ventilation structure. The air velocity had also enhanced the heating and drying rate. But after reaching 0.16 m/s, there was a further increase in the air velocity without considering the change rate of corn. The relative humidity shared little effect on the trend and value of corn temperature. But the relative humidity decreased the drying rate, whereas increased the equilibrium moisture content of corn. The higher air temperatures resulted in a higher drying and heating rate with a lower content of equilibrium moisture. According to the corn temperature and moisture content under different conditions, the combination of ventilation parameters was achieved in the air relative humidity less than 75%, air velocity of 0.09-0.23 m/s, and air temperature with atmospheric conditions. The relative errors between the simulated and experimental values of the moisture content of corn in the pilot test of ventilated drying ranged from 1.3% to 16.7%, with an average value of 4.4%, indicating the further practicality of the constructed model. Then the moisture contents of the corn in the innermost, middle, and outermost layers approached the safe moisture content around 130, 180, and 250 h, respectively. The unit energy consumption of ventilated drying of corn was 890.2 kJ/kg, which was remarkable for energy saving. The quality indexes also showed the feasibility of ventilated drying and storage of high-moisture corn. Therefore, ventilation and grain circulation were recommended in practical production, in order to improve the unevenness of temperature and humidity of the corn pile. These findings can also provide valuable theoretical support to optimize the corn-ventilated drying. [ABSTRACT FROM AUTHOR]

In order to analyze the impact of water-induced deterioration of soft rocks on the bearing capacity of surrounding rocks and evaluate the safety of water tunnels, this study took the silty sandstone in the water supply tunnel at the Lanzhou Water Source Construction Project as the research object, and carried out uniaxial and triaxial compression tests under different rock soaking times, in which the moisture deterioration process of silty sandstone was equivalent to the reduction of surrounding rock elastic modulus and strength, and conducted a simulation analysis on the safety of the water tunnel during construction and operation, considering the moisture degradation of surrounding rocks. The results indicate that as the soaking time increases, the uniaxial compressive strength of the rock samples gradually decreases, the maximum axial strain gradually increases, and the peak deviatoric stress of the rock samples under triaxial compression conditions gradually decreases. During the construction period, the displacement of surrounding rocks in the silty sandstone tunnel increases with the acceleration of moisture diffusion depth. During the operational period, the deterioration of surrounding rock results in increased displacement and principal stress of the segment lining, as well as the opening between pipe sections, which makes the tunnel easier to leak. The reinforcement of surrounding rocks and the filling of pebble stones effectively reduce the opening between the segments, shift the most unfavorable position of stress on the segments from the arch bottom to the arch top, reduce the possibility of tunnel leakage, and facilitate the safe operation of the water tunnel. [ABSTRACT FROM AUTHOR]

Statistical analysis was used to analyze the influences of meteorological factors such as temperature and precipitation on the sugar content of sugarcane. Random forest and forward stepwise selection algorithms were utilized to screen the key meteorological factors. Based on the generalized additivity model and so on, six sugar content simulation models were constructed to simulate the sugar content of sugarcane at the maturity stage with the key meteorological factors as independent variables. Evaluate the simulation effects and quantify the influences of key meteorological factors on the sugar content of sugarcane by comparing and analyzing the simulated and measured values. The results showed that the meteorological factors in different regions and time scales affected the sugar content of sugarcane. The key meteorological factors include diurnal variation of temperature, minimum ground temperature, sunshine hours, maximum temperature, average air pressure, precipitation, and average relative humidity. The influence of diurnal variation of temperature on the sugar content of sugarcane showed a nearly stable linear trend, while the influences of the other key meteorological factors on the sugar content of sugarcane showed a complex fluctuation trend. Based on the key meteorological factors, six models were established to simulate the sugar content of sugarcane. The generalized additive model had the best simulation effect, with the fit R2 up to 0.97, the absolute error was 0.12 percent points, the relative error was 0.86%, and the root mean square error was 0.15 in the model validation. It indicates that the simulated values have good consistency and correlation with the measured values, and the model can realize the prediction of the sugar content of sugarcane in Guangxi. Meanwhile, quantifying the effects of key meteorological factors on the sugar content of sugarcane also provides a basis for regulating the ecosystem. [ABSTRACT FROM AUTHOR]

Hydrogen/natural gas fuel combustion can reduce CO2 emissions, which is conducive to alleviating the greenhouse effect. In this paper, the combustion characteristics of hydrogen/natural gas hybrid fuel are studied based on FLUENT simulation software. The selected research model is a gas-fired boiler. Under the conditions of different hydrogen mixing ratio, different excess air coefficient and different fuel composition, the variation rules of temperature field, velocity field and nitrogen oxide concentration field in the furnace are mainly studied, and the preliminary explanation and analysis are carried out from the mechanism. The results show that the NOx emission will increase with the increase of hydrogen mixing ratio; When hydrogen mixing ratio is 10% and excess air coefficient is 1.05, the average temperature and NOx concentration of furnace outlet section are the largest. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As most anomaly detection methods generally ignore the impact of video quality fluctuations in actual scenarios on their performance. Firstly, public datasets from the field of video anomaly detection were selected, and a distortion dataset for anomaly detection by artificially introducing common distortions found in surveillance videos through simulation methods was constructed. This paper systematically analyzes the impact of video quality fluctuations on the performance of four classic video anomaly detection algorithms. And the experimental results show that the degradation of surveillance data quality have a negative effect on the effectiveness of the video anomaly detection algorithm. Moreover, the impact of different distortion types and different degrees of distortion on the algorithm is different, as well as, Gaussian noise distortion and over brightness distortion have a greater impact on the algorithm. [ABSTRACT FROM AUTHOR]

To solve the parameter tunning problem of PID controllers in master-slave control structure of electro-hydraulic servo system, this paper proposed a solution method based on multi-objective optimization algorithm combined with model simulation. This method modeled the problem as a multi-objective optimization problem whose target space included four dimensions, namely master-slave synchronization error, settling time, overshoot and integral squared error. And it established the simulation model of master-slave PID control structure to obtain the target value of the target space. Additionally, it improved the MOEAD algorithm by strengthenning the diversity of generated offspring through the selection of parents along with the offspring generate operators and readjusting the weight vector through the substitution strategy of invalid ones using external populations and binding mechanism between weight vectors and individuals. Finally, this method got the final Pareto non-dominated solution set and then selected the knee point individual as the optimal parameter of the controller in the solution set, which improves the control quality of the master-slave synchronization structure. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Selective laser sintering technology is not limited by the shape of the parts, and can form parts with complex structures. Selective laser sintering technology is widely used in rapid prototyping manufacturing and new product design and development. It is particularly important to explore the dimensional accuracy of its forming. Aiming at the problem of low dimensional accuracy and shape accuracy of thin-walled shell parts, this paper proposes a method of preprocessing and precompensation based on part features to improve printing accuracy. Taking polystyrene as raw material, under the combination of simulation and experiment, in order to compensate the deformation, the method of adding support and offset margin is used to correct the feature size, which is easy to warp and deform, and the laser parameters are adjusted to improve the heat accumulation in the printing process. By verifying the printing results, the results show that under the same process conditions, the change of the geometric features of the part directly affects the dimensional accuracy of the part. After adding support settings and predeformation compensation to the part features, the printed parts are compared with the 3D model with good detection results, and the actual error can basically be controlled within 0.3 mm. [ABSTRACT FROM AUTHOR]