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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 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.)

Pineapple is one of the four major tropical fruits with important profits. China has been the fifth-largest producer of pineapple in the world, particularly with a large number of planting areas. Manual harvesting cannot fully meet the large-scale production of pineapples at present. Mechanical harvesting can be expected to improve the efficiency of pineapple production with labor cost savings. It is of great significance to develop mechanized equipment for pineapple production. Among them, the lever-feeding pineapple harvester has been developed for the batch harvesting of pineapples. Compared with robotic picking, it is no necessary to adjust the working parameters during harvesting plants with different heights. Therefore, the harvest speed is much higher than that of the manual and robot. However, the low success rate has been confined to collecting and conveying the harvested pineapple fruit. Many pineapple fruits are prone to damage during transport. In this study, a double-row alternating toothed sieve was designed for pineapple collecting and conveying. The device served as the intermediate or transitional conveying mechanism between the fruit receiving plate and the baffle conveyor chain. The motion equation was then established for the tip of each of the tooth-shaped sieve plates in the double-row alternating tooth-shaped sieve. A systematic analysis was made on the motion trajectory of each tooth tip in the conveying mechanism. The structural parameters of the conveying mechanism were determined, such as the length and angle of the rods, and the spacing distance between the toothed sieve plates. After that, the mechanics model was established to express the contact between pineapple fruit and the tooth-shaped sieve plates. The pineapple fruit damage-free and bounce-free boundary conditions of the conveying speeds were obtained for the conveying mechanism using the mechanic model. Furthermore, the key influencing factors were determined as the experimental parameters, including the inclination angle of the receiving plate, the rotational speed of the picking device, and the rotational speed of the conveying mechanism. A three-factor three-level frame experiment was conducted using the BoxBehnken, with the success rate of pineapple fruit conveying and the number of retained fruits as the evaluation indicators. The combination of optimal parameters was then obtained using the regression model. The field test also showed that the average fruit conveying success rate was 94.87%, and the average number of retained fruits was 2 when the inclination angle of the receiving plate was 14°, the rotational speed of the picking device was 27 r/min. and the rotational speed of the conveying device was 70 r/min. Besides, there was no damaged fruit during conveying. The device can fully meet the needs of pineapple fruit conveying. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

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.)

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants 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.)

Unsaturated soil desiccation cracking is a coupled hydro-mechanical problem. It seriously weakens the hydraulic and mechanical characteristics of soil, causing various natural disasters potentially. For the unsaturated soil, the mechanism of moisture diffusion and deformation is more complicated compared with saturated soil, attracting wide attention. Thus, a coupled hydro-mechanical bond-based peridynamic (BB PD) model was proposed to explore the moisture diffusion and crack propagation in unsaturated soil. Specifically, the moisture diffusion equation for unsaturated soil was recast with the peridynamic differential operator, and an improved micro-modulus was adopted to revise the bond force density in the BB PD. In addition, a hybrid algorithm combining the explicit difference scheme for solving the diffusion equation and the implicit scheme for solving the motion equation was adopted, to avoid the incongruity of time steps for two types equations under the same explicit scheme. The validity of the proposed model and algorithm was verified by the examples on the desiccation of an unsaturated soil block and the desiccation cracking of a 3D unsaturated soil plate. The results show the potential of peridynamics in capturing desiccation cracks of unsaturated soil. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

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.)

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics 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.)

A two degree of freedom translational decoupling parallel micropositioning stage based on parallel flexure mechanism was proposed. A compound double parallel four-bar flexure mechanism module was adopted in the stage, and structural symmetry constraints were introduced to eliminate the coupling between shafts and parasitic displacement, and translations in X and Y directions were achieved. The stiffness matrix method was used to analyze the parallel flexure mechanism in theory. According to the observation method, the overall stiffness matrix of the micropositioning stage was established, and the differential equations of motion of the system were obtained, and the natural frequencies of each order of the system were deduced. The modal analysis of the micropositioning stage was carried out by using the finite element method, and the natural frequency and mode shape of the micropositioning stage were obtained. Through theoretical analysis, finite element calculation and experimental test, the consistency of the results shows the correctness of theoretical analysis and the effectiveness of stiffness matrix analysis. [ABSTRACT FROM AUTHOR]

The mass analyzer based on quadrupole field theory, including quadrupole and ion trap, control and screen ions by a non-magnetic, alternating electric field, which was the first proposed by Professor Paul in 1953. Since the birth of quadrupole, ion trap and other related mass spectrometry technologies have been developed relatively maturely, which have made a significant impact and contribution to mass spectrometry. This paper deduced and interpretd the complete physical and mathematical formulae of the design and generation process of the quadrupole field. The process of obtaining the potential distribution of the quadrupole field, the obtaining process of boundary conditions such as electrode shape and voltage on the electrode, and the process of deducing the quadrupole structure and ion trap structure according to the potential distribution of the quadrupole field were discussed. In the above processes, for the purpose of binding ions, a general potential (Prof. Paul called it “allgemeinste potential” in German) distribution equation was obtained by introducing a simple harmonic motion model. And then, according to the basic laws of electromagnetic field and Maxwell’s equation, the condition of zero electric field divergence was introduced. Based on this, through the discussion of the two simplest solutions and boundary conditions, the structure and field distribution equations of the quadrupole and the ion trap were obtained, respectively. This content was an important supplement to the elaboration on the theory of quadrupole field mass spectrometry, which was helpful for a deeper understanding of basic principles of quadrupole field. At the same time, this paper provided a potential mass analyzer design method. Firstly, the design began with the conception of the state of ion motion, and then a force that could control the movement of ions according to the idea was found. Secondly, combined with the basic laws of electromagnetic fields, the general equation and its limiting conditions for the potential distribution that could form this force were obtained. Thirdly, according to the easy-to-operate settings in practice, the boundary conditions of the field (such as electrode shape, electrode voltage, etc.) were obtained, and the intermediate variables in the general equation were replaced with these operable physical parameters. At last, according to the potential distribution equation, the ion motion equation was calculated, and the mathematical relationship between the masstocharge ratio and the controllable physical parameters was found. And finally, a mass analysis method for controlling and separating ions was obtained. This kind of design method has important reference significance for theoretical research and original innovation research related to mass spectrometry. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) 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.)

Based on the Davenport wind speed spectrum, the responses of 6-parameter practical viscoelastic damping energy dissipation structures were studied systematically. Firstly, the differential constitutive relation of the 6-parameter viscoelastic damper was used to establish the motion equation of the energy dissipation structure under the Davenport wind spectrum excitation. Then, the motion equation was transformed from the 2nd-order differential equation to the 1st-order one by means of the complex mode method, and the frequency-domain solution and the power spectral density function expression of the energy dissipation structure system under wind excitation were obtained. Finally, based on the random vibration theory, the analytical solutions of the response of the energy dissipation structure system under the Davenport wind spectrum excitation and the force response of the damper, were obtained with the mathematical identity. This method not only contains the results of the all-vibration-mode expansion of the structure system under wind excitation, but also has more simple and efficient expressions than existing methods, and applies to nonclassical structures. [ABSTRACT FROM AUTHOR]

A closed-form solution of responses of SDOF structures with SPIS-Ⅱ dampers under seismic excitation modeled with the Clough-Pezien spectrum was proposed, and the shock absorption performance and influential factors of this system were studied based on the proposed method. Firstly, the motion equation for the SPIS-Ⅱ damper was established, and the unified expressions of frequency domain solutions of structural responses, such as the structural displacement and the inerter force, were obtained. Secondly, based on the rational expression decomposition and the residue theorem, the quadratic orthogonal equations of the frequency response eigenvalue function and the Clough-Pezien spectrum were obtained respectively, and in turn the quadratic orthogonal equation of the structural response power spectrum was deduced. Thirdly, the concise closed-form solutions of the 0~2nd-order spectral moments of the structural responses were acquired. The proposed method and the virtual excitation method were used to analyze a case respectively, which verifies the correctness of the proposed method. Finally, the proposed method was used to analyze the effects of the inerter parameters on the seismic performances of the structure. The research shows that, the proposed method gives closed-form solutions better than those given by the virtual excitation method in terms of computation efficiency and accuracy. The damping performance will improve with the increase of μm and μξ for a constant μω and the damping performance will reach the optimum for μω=1. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

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 Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic 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.)

The prevention and control of the disaster of water-sand mixture inrush caused by mining is becoming one of important bottlenecks, which restricts mining safety. The state-of-the-art and trend of water-sand mixture inrush from seam roof were reviewed, including the catastrophic mechanism, movement law and risk evaluation. The engineering geological models of disaster formation are divided into four categories, including water-sand mixture inrush by direct or indirect exposure of unconsolidated aquifers, by seepage failure due to water-conducting fractured zone connecting, by man-made borehole drilling through unconsolidated aquifers, and by softened overburden with deterioration of water and inrush under the combined action of water pressure and mining pressure. In view of the seepage failure of water-sand mixture inrush, combined with the model test and theoretical derivation results, the basic movement law of the water-sand mixture flow through the orifice, single fracture, fracture network and caving zone was obtained, which lays the foundation for the establishment of a unified equation of the movement of water-sand mixture flow. An expression of critical hydraulic gradient from top to bottom seepage was derived, and the concept and calculation method of safe water head against water-sand mixture inrush were proposed. A qualitative and quantitative evaluation method for water-sand mixture was established, and a dynamically quantitative evaluation method for water-sand mixture inrush was realized. The successful application of active prevention and control measures was introduced by grouting to transform the properties of unconsolidated aquifers and backfill mining, in order to reduce overburden failure and prevent water-sand mixture inrush failure. Finally, the scientific problems of the mechanism of water-sand mixture inrush from seam roof and key technical issues, which should be solved in the next step of prevention and control, were proposed. The main scientific issues include that establishment of a digital twin model of the geological geology of water-sand mixture inrush from seam roof, revealing the formation mechanism of the water-sand mixture inrush pathway, the interaction between the water-sand mixture and the surrounding rocks, constructing the motion equation reflecting the whole process of water-sand mixture inrush, obtaining the grout propagation and solidification characteristics in the advanced area of preventing water-sand mixture inrush, etc. Research and development of key technologies include monitoring and early warning technology, actual environment modeling technology, and equipment for high-efficiency grouting. [ABSTRACT FROM AUTHOR]

Aimed at the internal short circuit problem due to large deformation of the prismatic lithium-ion battery cell under impact loadings, a simplified battery model was first established. Then the motion equations of velocity and displacement based on the membrane factor method were proposed. With the effects of the face-sheet thickness and the densification region on the normalized final deflection, impact response characteristics of prismatic battery cells were investigated in detail. The results show that, the improved motion equations involving the membrane factor can reflect the dynamic response mechanisms of the prismatic battery cell under impact loadings, and the large deflection under high-speed impact can be predicted. With the increase of the face-sheet thickness, the deflection of the battery cell ’s lower part decreases obviously. However, the densification region expands with the face-sheet thickness. The deflection and the [ABSTRACT FROM AUTHOR]

The lubrication characteristics of oil film of valve-plate pairs were of great significance for reliable operations of axial piston pumps. A simulation model was developed for oil film lubrication characteristics of spherical valve-plate pairs with conical cylinder block, and the effectiveness of the model was validated using experimental tests. First, the forces acting on conical cylinder blocks were analyzed, and the forces acting on cylinder blocks generated by piston-slipper assemblies were obtained by analyzing the kinematics and dynamics of piston-slipper assemblies. Second, the oil film carrying forces were obtained by analyzing the thickness and pressure distributions of oil films in spherical valve-plate pairs. Third, the oil films were discretized using finite volume method, and the oil film lubrication characteristics of spherical valve-plate pairs and the equation of motion of conical cylinder blocks were numerically solved using Newton iterative method. Last, the high-pressure steady-state tests and the surface profile scanning tests were performed, the morphologies of spherical valve plates with different steady-state test durations were obtained, the spherical valve-plate wear profile and the simulated oil film thickness and pressure distributions were compared. Results show that the simulated thick oil film area is in consistence with spherical valve-plate main wear areas, indicating that the oil film lubrication model of spherical valve-plate pairs with conical cylinder block is effective. [ABSTRACT FROM AUTHOR]

Net enclosure aquaculture is one of the most important ways for farming fish and economic animals. Among them, nets, piles, ropes and iron chains can be used to delineate a certain water column in the shallow seas. More than 10 net enclosure facilities have been built across the country from the Shandong to Guangdong Province in China in recent years. However, only a few studies have been focused on the hydrodynamic performance of net enclosure aquaculture and emerging marine aquaculture facilities. The net enclosure facilities are still in the early stages. It is also lacking under the extreme ocean load resistance of aquaculture engineering structures. In addition, there is no such structural design theory or standard specifications for the net enclosure design and installation, particularly on the safety assessment. In this study, a net enclosure aquaculture facility was numerically investigated using the lumped mass model. A Newton’s second-law-based motion equation was then solved using Euler’s method. Finally, the MATLAB platform was used to visualize the calculations. The results showed that the maximum force of ropes was found in the second horizontal rope and the third horizontal rope under the still water level. Furthermore, the maximum forces of ropes and net twine were get the wave-current directions of 0°, 10°, 40°, 60°, and 80°, respectively, when the wave and current were 4 m, and 1.0 m/s, respectively. The force on the netting was tilted to the right (incident direction), as the incident angle was changed gradually. As such, the force on the right side of the rope was much greater than that left side. The maximum force on the right side of the horizontal rope was 27.04% higher than that on the left side at the wave-current incident direction of 10°. Moreover, the maximum forces on the right side were 42.44%, 86.01% and 92.15% higher than that on the left side in the wave-current incident direction of 40°, 60˚ and 80°, respectively. The maximum displacement of the net decreased greatly, as the incident angles increased and the maximum positions of the net moved to the left. The force of the net significantly increased with the waves. The load of the entire net was mainly from the top half of the net. The main force of the net twines was distributed in the six areas that were divided by the first three horizontal ropes and the two vertical ropes. The maximum force on the net twines occurs at the position on both sides above the second horizontal rope under the water surface. The force of net twines on the right side of the rope was greater than that on the left side, with the change of the incident direction. The maximum force decreased rapidly at the incident angle of 40°-80° under the combined wave-current conditions. The maximum force of joint points appeared at positions 1, 2, 3, and 4. The numerical simulation was then performed on the net of the seam-edge type net enclosure aquaculture facility in use. The force distribution and deformation were achieved in the seam-edge type net enclosure. The finding can provide the theoretical basis for the design, installation, and reinforcement of aquaculture facilities. In addition, it was necessary to focus on the inspection and reinforcement after the event of extremely bad weather. [ABSTRACT FROM AUTHOR]

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.)

Given the requirement of more targets, lower track rate, higher track precision of radar, an extended Kalman filter (EKF) algorithm based on ballistic equation is proposed. Centroid motion equation of ballistic missile in midcourse and reentry is established, and EKF algorithm is improved. Through comparing to conventional EKF algorithm based on constant acceleration model and unscented Kalman filter (UKF) algorithm based on ballistic motion equation, EKF algorithm based on ballistic equation has higher filter precision, faster computation speed, which solves the practical problems in radar. [ABSTRACT FROM AUTHOR]

Many slender rods in engineering can be modeled as Euler-Bernoulli beams. For the analysis of their dynamic behaviors, it is necessary to establish the dynamic models for the flexible multi-body systems. Geometric nonlinear elements with absolute nodal coordinates help solve a large number of dynamic problems of flexible beams, but they still face such problems as shear locking, nodal stress discontinuity and low computation efficiency. Based on the theory of large deformation beams’ virtual power equations, the functional formulas between displacements and rotation angles at the nodes were established, which can satisfy the deformation coupling relationships. The generalized strains to describe geometric nonlinear effects in this case were derived. Some parameters of boundary nodes were replaced by axial strains and sectional curvatures to obtain a more accurate and concise constraint method for applying external forces. To improve the numerical efficiency and stability of the system’s motion equations, a model-smoothing method was used to filter high frequencies out of the model. The numerical examples verify the rationality and effectiveness of the proposed element. [ABSTRACT FROM AUTHOR]

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 Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe 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.)

The nonlinear vibration responses of functionally graded materials (FGMs) shells with different cone angles under external loads were studied. Firstly, the Voigt model was employed to describe the physical properties along the thickness direction of FGMs conical shells. Then, the motion equations were derived based on the 1st-order shear deformation theory, the von Kármán geometric nonlinearity and Hamilton ’s principle. Next, the Galerkin method was applied to discretize the motion equations and the governing equations were simplified into a 1DOF nonlinear vibration differential equation under Volmir ’s assumption. Finally, the nonlinear motion equations were solved with the harmonic balance method and the Runge-Kutta method, and the amplitude frequency response characteristic curves of the FGMs conical shells were obtained. The effects of different material distribution functions and different ceramic volume fraction exponents on the amplitude frequency response curves of conical shells were discussed. The bifurcation diagrams of conical shells with different cone angles, as well as time process diagrams and phase diagrams for different excitation amplitudes, were described. The motion characteristics were characterized by Poincaré maps. The results show that, the FGMs conical shells present the nonlinear characteristics of hardening springs. The chaotic motions of the FGMs conical shells are restrained and not prone to motion instability with the increase of the cone angle. The FGMs conical shell present a process from the periodic motion to the multi-periodic motion and then to chaos with the increase of the excitation amplitude. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & 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.)

Copyright of Journal of Central China Normal University is the property of Huazhong Normal University 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 Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics 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.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & 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 Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

Large blocks of drift ice have posed a strong impact on the open channels in the long-distance water delivery projects in the alpine regions. The drift ice is easy to form with the different speeds and compression strength in the high latitudes of northwestern China, especially the north of 35°N latitude. Particularly, the ice period lasts for 4 to 5 months in the cold and dry winter, covering from the freezing in November to the open in the following spring. The long-term collision of drift ice can cause some serious damage to the concrete lining of an open channel, such as cracking or peeling of the surface. The lining structure can result in different degrees of damage and deformation, even a threat to the long-term stability of water supply, including the safe operation of the open channel, irrigation of farmland, and water use for humans and animals. Therefore, this study aims to clarify the impact of the drift ice on the open delivery channels in the long-distance water delivery projects in the alpine regions. A collision model of the drift ice and open channels was also established as a water-air coupling medium using the ANSYS/LS-DYNA platform. Specifically, the collision motion equation of drift ice in the open channel was obtained, according to the display of time integration. The contact-collision process was assumed as a symmetric penalty function. The fluid-structure coupling calculation was then implemented considering the coupling effect between water-air-flow ice-open channels. After that, LS-DYNA SOLVER software was used to simulate the collision and extrusion of drift ice and open channel under different working conditions. As such, the degree of the collision was classified to evaluate the damage caused by the drift ice to the lining of the open channel. An indoor model test was carried out to verify the model. A damage law of drift ice was thus found in the water-air coupling medium when colliding with the open channel. The results showed that there was an approximate Pseudo-Voigt function peak curve relationship for the maximum equivalent stress and the maximum displacement in the X direction of the impact of the ice velocity on the open channel lining. Besides, there was an approximately linear relationship for the maximum equivalent stress and the maximum displacement in the X direction of the impact of drift ice compression strength on the lining of open channels. Furthermore, a combination interval posed a significant impact on the open channel lining, where the compressive strength of the flowing ice was 1.825-3.199 MPa, and the speed of the flowing ice was 3.5-4.5 m/s. This equivalent stress value of impact was 4.3-16.8 MPa, and the maximum displacement value in the X direction was 2.59×10-5-5.52×10-5 m. More importantly, a two-factor combination was posed the greatest impact on the open channel lining impact, where the flow ice compression strength of 3.059 MPa, and the flow ice velocity of 4.0 m/s. This equivalent stress value of impact was 16.8 MPa, and the maximum displacement value in the X direction was 5.52×10-5 m. By contrast, the combination interval presented a fewer outstanding impact on the open channel lining, where the drift ice velocity of 0.5-1.0 m/s, and the compressive strength was 1.825-2.375 MPa. This equivalent stress of impact was 0.7-2.8 MPa, and the maximum displacement in the X direction was 0.24×10-5-0.52×10-5 m. Therefore, there was a significant correlation between the temperature and the compressive strength of drift ice, while the flow velocity and the speed of drift ice. Correspondingly, the influence of the ice load needed to be considered in the design stage of the open channel lining structure. The findings can also provide sound theoretical and technical support to the safe operation of long-distance water transportation projects for the alpine regions in winter. [ABSTRACT FROM AUTHOR]

The transient phase-frequency characteristics of stay cables with different cable forces were studied in view of the cable sag and geometric nonlinearity. The method of multiple scales was used to solve the ordinary differential equations of motion for cables subjected to in-plane distributed excitations, and the approximate analytical expressions of in-plane and out-of-plane primary resonance responses were obtained respectively. Then, the transient phase difference and its amplitude between the response and the excitation were obtained through the Hilbert transform. The rule and reason for the transient phase difference between the response and the excitation under different cable forces were studied. The results show that, the phase difference between the out-of-plane response and the excitation is constant, while for the in-plane one it is related to the elastic parameters and the sag of the cable. A small change in cable tension may result in a significant change in the transient phase-frequency characteristics. The main reason is that there are a twice-frequency term and a drift term in the approximate solution of the in-plane response, the former makes the transient phase of response appear twice positive-negative alternations in a single cycle, and the latter determines the maximum value and the variation law of the transient phase difference between the in-plane response and excitation. [ABSTRACT FROM AUTHOR]

Collective cell migration occurs in various physiological and pathological processes such as embryonic development, wound healing and tumor invasion. Studies on collective cell dynamics are crucial for understanding the mechanism underlying collective cell migration and its related biological processes. Here, a 3D multicellular model was proposed based on elastically deformable shells. The equations of motion on the vertices of the cell were established. A 3D collective cell dynamics theory involving cell deformations and intercellular contact with adhesion was established, and the corresponding numerical algorithm was developed. Based on the developed dynamic model, the rotation of collective cells confined in a spherical lumen was simulated. The simulation reproduced some experimental observations. Further, the effects of cell polarity, cell deformations and intercellular interactions on the 3D dynamics of collective cells were analyzed. [ABSTRACT FROM AUTHOR]

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A size?dependent quasi-3D functionally graded (FG) microbeam model was presented within the combined framework of the modified couple stress theory and a 4-unknown higher-order shear and normal de? formation theory. Then the model was applied to analyze the static bending and free vibration of FG mi-crobeams. With the 2nd Lagrange equation, the corresponding motion equations and the appropriate boundary conditions were obtained. A 2-node 16DOF differential quadrature finite element combining the Gauss?Lobatto quadrature rule with the differential quadrature rule was constructed to handle the general static / dynamic boundary value problems of FG microbeams. A comparison study was performed to show the efficacy of the proposed theoretical model and solution method. Finally, the effects of the gradient index, the intrinsic length scale parameter, the geometrical parameters and the boundary conditions on the static and dynamic characteris-tics of FG microbeams were examined. Numerical results reveal that the developed beam model and element are applicable to the analysis of mechanical behaviors of FG microbeams with various slenderness ratios. Besides, introduction of the couple stress effect can significantly change the static and dynamic characteristics of FG microbeams. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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.)

Copyright of Journal of Central China Normal University is the property of Huazhong Normal University 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 Natural Gas Geoscience is the property of Natural Gas Geoscience 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.)

Transplanting has become a common practice in tomato cultivation, where seedlings grown in doors are replanting into a final planting location for the growing season. Most tomato planting is distributed in Xinjiang of northwest China, due mainly to high difference in temperature, long sunshine, and less rainfall. Weather factors such as hail and cold in early spring seriously determined the survival of tomato seedlings. However, a combination of semi-automatic machine and manual transplanting was generally adopted in current tomato planting, indicating low transplanting efficiency and high labor intensity. Therefore, it is necessary to develop a high-speed automatic transplanter suitable for large-scale tomato planting. Since the picking speed can reach 120 plants per minute in previous automatic transplanters, the planting speed is not so high, the maximum of only 60 plants per minute. Furthermore, the planting speed also determined the transplanting speed of the automatic transplanting machine. In this study, a double-row seedling cast device was designed with high efficiency, continuity, and damage resistance in transplanting seedlings. The specific procedure was as follows. 1)Two workstations were alternately utilized to implement the continuous casting of seedlings. The assembled cylinder in front of the base was used to push the rotation of the cast around the bearing center that connected to the base.2)A coordinate system was established from the side view of cast movement, considering the influence of air resistance on the motion. 3)Motion equations were set in two dimensions (the horizontal and vertical) to determine the main factors of seedling injection, including the inclination angle of seedling,the height, and speed of the cast. A three-level single factor orthogonal test was carried out to evaluate the influence of each single factor. The experimental procedure was that: 1)Five height levels were taken as test variables, showing that the damage rate was low, whereas, the success rate was high, at the height between 125 mm to 160 mm. 2)Five cast speeds were chosen between 40 to 120 plants per minute, showing that the damage rate was going up as the cast speed increased. The best success rate was achieved, when the cast speed reached 60 plants per minute. 3)The success rate was found higher, as the inclination angle of seedlings was higher. The results showed that the influence of each factor on the success rate was ranked: the inclination angle, cast speed, and height. The order of damage rate was like this: cast height, cast speed, and inclination angle. Then, a Box-Benhken response surface method (RSM) was used to determine the interaction of three factors, indicating that the main factor of success rate was the inclination angle, whereas the damage rate was the cast height. Besides, an optimal combination of three factors was obtained after the working parameters were optimized in the Minitab platform. Finally, a field test was conducted to verify the operating parameters, where the success rate of seedling planting was 96.41%, while the matrix damage rate was 1.65%. Further, the deviations of success and damage rate were 0.34% and 4.27%, respectively, meeting the requirements of the seedling throwing operation. The findings can provide a promising reference to develop high-speed automatic transplanters in tomato cultivation. [ABSTRACT FROM AUTHOR]

Accurate dynamic parameters are essential to more reasonably design grain group silos under earthquake action. In this study, the vibration characteristics of large-scale grain silos were analyzed, considering 15 silos in three rows and five columns in a grain storage project. The specific procedure was as follows. 1) A feasible optimization scheme was proposed for the ambient vibration test of grain group silos using structural vibration and finite element method (FEM), together with the structural and load symmetry in the actual engineering condition. 2) The measuring points were drawn in the corner silo (No. 11) and the side silo (No. 12), and then the point elevation and orientation were all listed in the tables. The acceleration signals of measuring points were obtained after the test. The least square, five-point three-smoothing, and digital filtering were then used to efficiently process the measured data. 3) The mode shapes of grain group silos were derived using control theory and motion equation of vibration via the acceleration data and transformation matrix. The first four mode shapes and frequencies were calculated to draw for the corner silo (No. 11) and the side silo (No. 12). The results demonstrated that the mode shapes were all the same. In the first four mode frequencies, the calculated values were 2.28, 3.45, 6.37 and 8.26 Hz, respectively, and the simulated values were 2.35, 3.56, 6.31 and 8.16 Hz with an error of 3.07%, 3.19%, 0.94%, and 1.21%, respectively. In the vibration responses of the corner silo (No. 11) and the side silo (No. 12), the first mode shapes of the two silos were all along the short axis direction of the whole grain silos with the same shear deformation and the same amplitude, indicating that there was little effect of adjacent silos on the first vibration response. The second mode shapes of two silos were all along the long axis direction of whole grain silos with the same shear deformation but a different amplitude. The constraint effect among the corner silo (No. 11) and the adjacent silos was weaker than that of the side silo (No. 12) and the adjacent silos. Therefore, the vibration amplitude of the former was larger than that of the latter. The third mode shapes of two silos were torsion shapes around the center of grain group silos, while, the rotational amplitude of the measuring point in the short-axis direction was greater than that in the long-axis direction. The fourth mode shapes of the two silos were significantly different, due to different interactions among the corner silo (No. 11) and the adjacent silos and that of the side silo (No. 12) and the adjacent silos. Bending mode shapes of the measuring points of the corner silo (No. 11) near the side silo, and the amplitudes were relatively small, but the other points were mainly shear or flexural shear mode shapes, and the amplitudes were relatively larger. The reason was that three adjacent silos constrained the side silo (No. 12) to the small amplitudes. Bend-shear mode shapes were found in the measuring points near the adjacent silos, but the points of the middle column were mainly shear mode shapes. Each silo in the grain group silos represented different interactions with the adjacent silos at the measuring positions, indicating a significant impact on the second order and above modes. A seismic design of grain group silos can be expected to divide into several parts for better materials cost-saving, according to the shape and amplitude of vibration mode. [ABSTRACT FROM AUTHOR]

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