Advanced Materials Research Vols. 268-270

Abstract: This paper presents the results of a numerical study on the mixed convection in a lid-driven enclosure filled with a copper-water nanofluid and induced by two mutually orthogonal heated thin plates. Two different boundary conditions (isothermal boundary condition and isoflux boundary condition) are considered. The coupled gonverning equations are solved numerically by a fully fourth-order accurate compact finite difference method. A parametric study is conducted and a set of graphical results is presented and discussed to elucidate that significant heat transfer enhancement can be obtained due to the presence of nanoparticles.

Abstract: The basic idea of H₂-C mixture reduction reflexes using hydrogen as main reductor and carbon as main heat generator in iron bath smelt reduction reactors on purpose to cut down total energy consumption and CO₂ emission. The author applied the methods of modeling for separating regions and [1]complex integration to research the kinetics behavior of the reactor. Changes of temperature and concentration field in each region were calculated after modeling from theories for solid-liquid, solid-gas and gas-liquid reactions combining theories of shrinking core, combustion and deoxidization etc. Besides some boundary- and initial conditions were got from inlet variables, other conditions included substance and energy exchanges on boundaries between different reaction regions were determined from the translation of all boundary coordination. After dispersion treatment with Control-Volume-Method, the whole model was programmed into special software for digital simulation. Corresponding author: HONG Xin, Shanghai University, Phone/Fax: 021-56331176, E-mail: xhong@online.sh.cn

Abstract: The thermodynamic properties of AlNi are investigated by the full-potential linearized muffin-tin orbital (FP-LMTO) scheme within the generalized gradient approximation correction (GGA) in the frame of density functional theory. The calculated lattice parameter and bulk modulus are in excellent agreement with the experimental and other calculated results. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the dependences of relative volume V/V₀ on pressure P, cell volume V on temperature T, linear thermal expansion α and specific heat C_V on temperature and pressure are successfully obtained.

Abstract: Damage and failure of the fiber reinforced composites remain as a challenging research subject in the area of material science and engineering. In this study a novel particle assembly model is developed using two dimensional Discrete Element Method (DEM) for the purpose of simulating the damage and failure process of the single-fiber composite (SFC) under axial tension. Fiber (SiC) and matrix (Epoxy) are represented by particles bonded together through elastic parallel bonds which are calibrated by a series of numerical tests. The contacts between the fiber particles and matrix particles are directly accounted for the fiber/matrix interface which is represented by the contact softening model similar to the cohesive zone model (CZM) in the continuum mechanics. The single-fiber composite tensile test is carried out using the developed DEM model in order to evaluate the interactions between fiber breakage, interfacial debonding and matrix cracking. The numerical results have demonstrated the capability of the developed DEM model in simulating the entire failure process of each individual constituent of the single fiber composite. This study has also confirmed that the DEM model has unique advantages over the conventionally numerical models in terms of dealing with the evolution of microscopic damages in composite materials.

Abstract: A new method of NC machining simulation based optimization of cutting parameters is proposed. For the case of NC turning process, the method of extracting cutting parameters from NC programs is given. Based on the cutting theories, using linear weighted method, the multi-objective optimization function is constructed, and it is solved by complex method. The modification and storage strategy of parameters is also given. The application shows that the proposed method cannot only ensure the accuracy of NC code, but also provide the optimized cutting parameters under the constraints of appointed machine tools. It will be helpful for the optimization and intelligence of NC machining.

Abstract: In the practical application of push-pull based production planning and scheduling architecture, the manufacturing system was found lacking of collaborative mechanism, especially for a networked-manufacturing environment, which requires each individual manufacturer interact and cooperate with each other for a collaborative manufacturing. This paper presents a production planning and scheduling architecture for networked-manufacturing system based on available-to-promise, which can effectively merge forecast-driven production activity with order-driven production activity, thus ensures the steady and prompt supply of material, and also cooperation and mutual benefit of individual manufacturer. This architecture consists of 1) an ATP-based order management and decision-making system, 2) a push-pull based multi-plant master production schedule collaboration model, 3) a pre-reactive collaborative replenishment model, 4) a production scheduling model of unrelated parallel machine and 5) the corresponding production planning and scheduling methods for each model. By combining the concept of ATP, this architecture can not only provide resource planning for networked-manufacturing system, but also offer quick response and promise to customer requests.

Abstract: This Paper Addresses an Unrelated Parallel Machine Scheduling Problem with Job Sequence-Dependent Setup Times. Jobs Have Precedence Constraints. the Objective Is to Minimize the Makespan. the Problem Has Applications in Industries such as TFT-LCD, Textile Manufactures. the Problem Is NP-Hard in Strong Sense. Therefore, an Ant Colony Optimization (ACO) Algorithm Is Introduced to Solve this NP-Hard Problem. the Proposed ACO Tackles the Special Structure of the Problem. its Performance Is Evaluated by Comparing its Solutions with Cplex Method. the Results Show that ACO Outperformed the Cplex Method.

Abstract: This Paper Presents Development of an Available-to-Promise (ATP) System for Network-Manufacturing in a Global Environment where Multi-Plants Are Manufacturing Products Collaboratively and Are Globally Networked. within the Multi-Plant Mode, the ATP Process Is Challenged to Give Not only Quick Response but Also Precise Order Promising by Considering the Coordination of Production Planning and Scheduling among Plants. in this Paper, an Order Decision and Production Planning Integrated ATP Model Was Developed and a Series of Performance Analysis Experiment Was Conducted to Reveal the Impact of some Key Factors such as Planning Horizon, Batch Interval Etc. on Overall Profit.

Abstract: The Samples of Polycrystalline Diamond (PCD) Cutting Tool Were Machined by Adjusting the Main Parameters of Electrical Discharge Machining (EDM). after the Machining, the Phases Were Analyzed by X-Ray Diffraction Analyzer and the Surface Layer Microstructure Were Observed by Scanning Electronic Microscope. the Fundamental Component of Machined PCD Cutting Tool Affected Layer Was Obtained and the Reason of Bring Affected Layer Was Analyzed. the Relationship Curves between Pulse Width, Working Electric Current and Depth Affected Layer, Surface Roughness Were Summarized. the Relationship between PCD Cutting Tools that Was Machined by EDM and Cutting Tool Flank Width, Workpiece Surface Roughness Were Analyed.The Results Showed that to Adjust Electical Discharge Machining Parameter, such as Pulse Width and Machining Electric Currents, Can Reduce the Depth of Affect Layer and Extend the Service Life of PCD Cutting Tool.These Researches Provide Valuable Test Reference for Drawing up Electrical Discharge Machining Technics of PCD Cutting Tool and Cutting Tool’s Life.

Abstract: Maneuverability is an important part of the vehicle’s general abilities.This paper uses sofware Fluent to simulate the planar movement mechanism(PMM) experiment while turbulence modle is adoped.The results of steady-state tests and unsteady-state tests could be analyzed to the hydrodunamic coefficients of a Mini Automatic Underwater Vehicle(AUV)and the dymatic mesh is adoped to simulate the motion of heave,sway,pitch,yaw.Finally, the motion simulation platform was built with the hydrodunamic coefficients and the motion performance of the vehicle was analyzed.