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To provide some heat transfer and friction factor results for fin‐and‐tube heat transfer surfaces which may be used in air conditioning industry.

Numerical simulation approach was adopted to compare the plain plate fin and three types of radial slotted fin surfaces.

It is found that at the same frontal velocity (1.0‐3 m/s) the plain plate fin has the lowest heat transfer rate with the smallest pressure drop. The full slotted fin surface has the highest heat transfer rate with the largest pressure drop penalty. The partially slotted fin (where the strips are mainly located in the rear part of the fin) and the back slotted fin are some what in between. Under the identical pumping power constraint, the partially slotted fin surface behaves the best.

The results are only valid the two‐row fin surface.

The results are very useful for the design of two‐row tube fin surfaces with high efficiency.

This paper provides original information of slotted fin surface with radial strips from the field synergy principle.

Pressure-based methods have been demonstrated to be powerful for solving many practical problems in engineering. In many pressure-based methods, inner iterative processes are proposed to get efficient solutions. However, the number of inner iterations is set empirically and kept fixed during the whole computation for different problems, which is overestimated in some computations but underestimated in other computations. This paper aims to develop an algorithm with adaptive inner iteration processes for steady and unsteady incompressible flows.

In this work, with the use of two different criteria in two inner iterative processes, a mechanism is proposed to control inner iteration processes to make the number of inner iterations vary during computing according to different problems. By doing so, adaptive inner iteration processes can be achieved.

The adaptive inner iterative algorithm is verified to be valid by solving classic steady and unsteady incompressible problems. Results show that the adaptive inner iteration algorithm works more efficient than the fixed inner iteration one.

The algorithm with adaptive inner iteration processes is first proposed in this paper. As the mechanism for controlling inner iteration processes is based on physical meaning and the feature of iterative calculations, it can be used in any methods where there exist inner iteration processes. It is not limited for incompressible flows. The performance of the adaptive inner iteration processes in compressible flows is conducted in a further study.

To present a custom design and fabrication method for a novel hemi‐knee joint substitute composed of titanium alloy and porous bioceramics based on rapid prototyping (RP) and rapid tooling (RT) techniques.

The three‐dimensional (3D) freeform model of a femur bone was reconstructed based on computerized tomography images via reverse engineering and the 3D reconstruction accuracy was evaluated. The negative image of artificial bone was designed with interconnected microstructures (250‐300 μm). The epoxy resin mould of a hemi‐knee joint and the negative pattern of an artificial bone were fabricated on Stereolithography apparatus. Based on these moulds, a titanium‐alloy hemi‐knee joint and a porous‐bioceramic artificial bone were created by quick casting and powder sintering (known as RT) techniques, respectively. After assembling, a composite hemi‐knee joint substitute was obtained.

The 3D reconstructed freeform model of the femur bone conformed to the original anatomy within a maximum deviation 0.206 mm. The sintered artificial bone had interconnected micropores (250 μm) and microchannels (300 μm). After implanting in vivo, the composite hemi‐knee joint substitute matched well with the surrounding tissues and bones with sufficient mechanical strength.

Further in‐vivo research is needed to provide the evidence for tissue growth into the ceramic structures and long‐term viability and stability of the implant.

This method enhances the versatility of using RP in the fabrication of tissue‐engineered substitutes, especially when individual matching is considered. Although this paper took a customized hemi‐knee joint substitute as an example, it is capable of fabricating other artificial substitutes with a variety of biomaterials.

The purpose of this paper is to provide a systematic method to perform analysis and test for vibration‐thermal strain behavior of plastic ball grid array (PBGA) assembly by considering thermal and vibration loading mode. Also to investigate the dynamic behavior of PBGA assembly by considering loading modes for design and reliability evaluation of PBGA packaging.

A PBGA assembly prototype with different structure and material parameters is designed and manufactured. Based on investigation of the structural and physical parameters of PBGA sample, the vibration‐thermal strain test is developed to measure the strain distribution at the surface of the BT (bismaleimide triazine) substrates and PCB (printed circuit board) surface under vibration‐thermal cycling loading such as random vibration and the temperature is changed from 0°C to 100°C.

The test results show that the loading modes have different impact on PCB, EMC and substrate, respectively. In the meantime, it is shown that the characteristics of the compound mode is not the linear accumulative result by single vibration mode and single thermal loading mode as forecasted. The nonlinear mechanism for these modes application is the future work for progress.

It is very difficult to set up a numerical approach to illustrate the validity of the testing approach because the complex loading modes and the complex structure of PBGA assembly. The research on an accurate mathematical model of the PBGA assembly prototype is a future work.

It implies a potential design characteristic for future application of PBGA assembly. It also builds a basis for future work for design and reliability evaluation of BGA package.

This paper fulfils useful information about the thermal‐vibration coupling dynamic behavior of PBGA assembly with different structure characteristics, materials parameters.

The purpose of this paper is to deal with the problem of integration of production and maintenance policies. In this context, the authors consider production systems made of parallel machines producing a single product over a finite horizon made of equal periods for which a forecasted demand is known. The authors investigate the impact of switching production in case of failure of any given machine.

A mathematical model is first developed to find an optimal production plan which minimizes the average total storage, shortage and production costs. Then, using this optimal production plan and taking into account the influence of the production rate on the degradation of each machine, optimal preventive maintenance (PM) policies are proposed for the situations with and without switching.

Optimal production rates are determined for each production period and for each machine. Optimal PM periods are also computed for each machine.

Usually, in manufacturing systems, the production rate of a machine influences its failure rate. In case a machine fails, it takes a random time to repair it during which production is lost. The paper attempts to propose a switching policy (SP) according to which the lost production is compensated by all the other machines. The effects of the SP coupled with the PM strategy are shown through a numerical example.

Contrarily to previous works, the authors consider more realistic settings with a non-negligible random time for repairing failed machines. In order to compensate the lost production during the repair of a failed machine, a SP is proposed to transfer the load uniformly to all the other machines. As a result, those machines will produce at a higher production rate and will consequently have their failure rate increased. It will therefore be essential to determine an optimal PM schedule knowing that durations of these activities are not negligible. It is shown that the simultaneous implementation of periodic PM and load transfer in case of failure is the most economical integrated strategy.

In this paper three‐dimensional numerical simulations were conducted for the periodically developed laminar flow in the sinusoid wavy fin‐and‐tube heat exchanger.

A novel CLEARER algorithm is adopted to guarantee the fully coupling between the pressure and velocity, and it can not only speed up the convergence rate, but also overcome the severe grid non‐orthogonality in the wavy fin‐and‐tube heat exchanger. The influence of wave amplitude, fin pitch, tube diameter and wave density on fluid flow and heat transfer characteristics is analyzed under different Reynolds numbers.

The numerical results show that with the increase of wave amplitude, tube diameter or wave density, both the friction factor and Nusselt number will increase, and the increase rate of friction factor is higher than that of Nusselt number. It is interesting to note that, at low Reynolds numbers the Nusselt number increases with the decrease of fin pitch, while at high Reynolds numbers, the Nusselt number increases with the increase of fin pitch.

The numerical results presented in this paper may provide some useful guidance in the design of the wavy fin‐and‐tube heat exchanger with large number of rows of tubes.

As the saying goes, “food is heaven of people” the development of agriculture is not only related to the quality of human life but also profoundly affects the efficiency of economic operation. However, under the background of rapid economic and technological development, China’s agricultural modernization process is very slow and incompatible with the development trend of economic modernization. Therefore, it is particularly necessary to innovate the traditional agricultural development model to break through the bottlenecks encountered in the transformation process of agricultural modernization. The proposal of the agricultural logistics ecosphere is to solve the problems of poor industrial linkage, low technical level and backward operation mode in the development process of traditional agriculture, and it is an important starting point for agricultural supply-side structural reform. This study aims to answer three questions in three aspects, namely, what is the agricultural logistics ecosphere, analyzes the general composition of the agricultural logistics ecosphere and how the subjects of the agricultural logistics ecosphere cooperate. It also puts forward suggestions for the coordinated development of the agricultural logistics ecosphere under the leadership of Taoxin. Also, it inspires the transformation of the agricultural development model in other regions and countries.

This study adopts a case study and a qualitative analysis method to collate the first-hand and secondary data obtained from the interview and form a tertiary coding. It explores the mechanism of coordinated development of the agricultural logistics ecosphere from four levels: goal synergy, resource synergy, ability synergy and benefit synergy.

First, the formation of the agricultural logistics ecosphere will not be achieved overnight, as operational management matures and ecosphere experiences the germination-development-mature evolution process. Second, target synergy is the foundation and premise for the formation of agricultural logistics ecosphere: to attract external resources with Taoxin characteristic core resources, to attract external resources to achieve synergy, to provide a guarantee for the realization of the maximum value of the agricultural logistics ecosphere and then to realize the interest synergy of internal and external subjects. Third, driving agricultural products upward in the “10 + 1” model: it is the core resource of the agricultural logistics ecosphere led by Taoxin and attracts external subjects to gather with core resources to further improve the value of the ecosphere. The improvement of the value of the ecosphere can broaden the ecosphere network. This is both an important construction of the ecosphere, and it is also the path choice of the coordinated development of the agricultural logistics ecosphere.

This study has a very important practical value and theoretical significance. In practical terms, the integration of “primary, secondary and tertiary industries” is helpful to foster new momentum for the development of agriculture and rural areas and promote the general framework of the agricultural logistics economy, the analysis of the general mechanism and extension of the transition of the new economy.

A numerical study of natural convection of air in a vertical annulus has been conducted, where the inner wall is heated with constant heat flux at its inner side, the outer wall of the annulus being maintained at constant temperature, and the top and bottom plates are assumed to be insulated. The cases of radius ratio K = 3, aspect ratio A = 10∼30, and Ra* = 103∼1.7 × 107 have been simulated. Both axial conduction and surface radiation are taken into account to reveal their effects on the distributions of inner wall temperature and local Nusselt number. Emphasis is on the comparison between the numerical results and the relevant experimental data, and the comparison between numerical solutions with and without considering the surface radiation. The numerical results of heat transfer are found to be in good agreement with the corresponding experimental results in the literature. The dependence of average relative conductivity on aspect ratio and the effect of imperfection in top and bottom insulation on the inner wall temperature are also discussed.

To provide an improved version of SIMPLER algorithm which can enhance the convergence rate of the iterative solution procedure in the field of computational fluid dynamics analysis.

The improved version of SIMPLER algorithm is developed by modifying the coefficients of the velocity correction equation and implementing the correction of pressure within an iteration cycle.

The CSIMPLER algorithm (the improved version) can enhance the convergence rate for almost all cases tested, especially for the low under‐relaxation factor situations. The pressure correction term even can be overrelaxed to further enhance the convergence rate.

The CSIMPLER algorithm can enhance the rate of convergence to different degree for different problems. It can only be adopted to solve the incompressible fluid flow and heat transfer.

CSIMPLER is a simple and effectual method to enhance the convergence rate of the iterative process for the computational fluid dynamics analysis. The existing code of SIMPLER can be easily changed to CSIMPLER.

The paper developed an improved version of SIMPLER algorithm with some minor changes in the existing SIMPLER code.

The periodically fully developed laminar heat transfer and fluid flow of an array of non‐uniform plate length, aligned at angles to air flow direction, have been investigated by numerical analysis in the Reynolds number range from 15 to 410. To implement the periodic boundary condition in both streamwise and spanwise directions and to confine the computation exactly within one cycle, proposes a linear interpolation technique, which has been proved successful by comparing the results with those obtained in an extended domain. It has been found that with an increase in the ratio of the long plate length to that of the short plate and with a decrease in the ratio of the transverse pitch to the streamwise cycle length, both the Nusselt number and friction factor decrease. Comparison of the numerical results of Nusselt number and friction factor with relevant experimental results have been performed. The agreement should be judged reasonably good.