THERMAL STRESSES OF ROTATING ROLLS IN ROLLING PROCESSING

In a modern rolling mill, proper roll cooling has been identified as a critical factor in the problems of excessive roll wear and poor surface finish of rolled product. In this paper, an analytical solution to determine the cyclic stresses produced in the roll is developed. An understanding of the cyclic stresses can be utilized to evaluate roll wear and leads to proper cooling practices for increasing roll life and better product surface quality. In the present analysis, a rotating roll subjected to surface heat fluxes and convective cooling is considered under the assumption that it rotates at high speeds. The methods of the thermoelastic displacement potential and the general stress function are used to solve the governing partial differential equations in order to calculate the thermal stresses. Examples of typical rolling conditions are given to demonstrate the feasibility and applicability of the model developed     

In vitro antimicrobial and anti-inflammatory effects of herbs against Propionibacterium acnes

Propionibacterium acnes play an important role in the pathogenesis of acne by inducing certain inflammatory mediators and comedogenesis. The objective of this study was to evaluate the antimicrobial and anti-inflammatory effects of herbal extracts against P. acnes. Among the ten tested herbs, methanolic extracts of rose (Rosa damascene), duzhong (Eucommia ulmoides Oliv.), and yerba mate (Ilex paraguariensis) were found to inhibit the growth of P. acnes with respective minimum inhibitory concentrations of 2, 0.5, and 1 mg/ml. In addition, duzhong and yerba mate extracts reduced the secretion of pro-inflammatory cytokines such as tumour necrosis factor-α, interleukin (IL)-8, and IL-1β by human monocytic THP-1 cells pretreated with heat-killed P. acnes at a concentration of 0.1 mg/ml. Our results suggested that duzhong and yerba mate extracts possess both antimicrobial and anti-inflammatory effects against P. acnes and can possibly be used as therapeutic agents for acne.     

Effect of field-annealing on magnetostriction and tunneling magnetoresistance of Co/AlOx/Co/IrMn junctions

The magnetostriction (λ_s) and tunneling magnetoresistance (TMR) of two Co/AlO_x/Co/IrMn MTJ systems that were deposited on Si(1 0 0) and glass substrate were examined at RT and field-annealing with various thicknesses of AlO_x. One structure was a Si(1 0 0)/Ta/Co/AlO_x/Co/IrMn/Ta system, and the other was a glass/Co/AlO_x/Co/IrMn system. The experimental results reveal that, in the Si(1 0 0)/Ta/Co/AlO_x/Co/IrMn/Ta system, the ratio of TMR is maximal under the field-annealing condition, and is optimal at an AlO_x thickness of 26 Å as well as in the RT condition. EDS analysis demonstrates that, these results are related to the distribution of Co and O atoms, because the oxidation of AlO_x is most extensive at a thickness of 26 Å. In the glass/Co/AlO_x/Co/IrMn system, λ_s does not significantly vary under the RT condition; however, λ_s is maximized (?20 ppm) by field-annealing at an AlO_x thickness of 17 Å. The abundance of Co and O in the system dominates the behavior of λ_s, according to EDS analysis. Finally, the minimum value of λ_s and the maximum ratio of TMR are ?8 ppm and 60%, respectively, at an AlO_x thickness of 26 Å under the field-annealing condition.     

Group-Based Authentication and Key Agreement

This paper presents an authentication and key agreement protocol to streamline communication activities for a group of mobile stations (MSs) roaming from the same home network (HN) to a serving network (SN). In such a roaming scenario, conventional schemes require the SN to interact with the HN for authenticating respective MSs, at the cost of repeated message exchanges and communication delay. Instead, in our design, when the first MS of a group visits, the SN performs full authentication with the concerned HN and thereby obtains authentication information for the MS and other members. Thus when any other MS of the same group visits, the SN can authenticate locally without subsequent involvement of the HN, so as to simplify protocol operations. We will show that our scheme does not trade performance for security and robustness to the extent that security requirements are unduly weakened. Both qualitative and quantitative discussions indicate that our proposed scheme lends itself to pragmatic settings.     

Simpler Throughput Analysis of CDMA/Unslotted ALOHA Radio Networks with Variable Message Length Based on M/M/inf Queueing Model

We propose a new and exact method to analyze the throughput of the DS CDMA unslotted ALOHA system with variable number of fixed-length packets. The proposed scheme requires two-dimensional summation while the previous requires four. Thus the proposed analysis scheme is of less computational complexity. The proposed analysis result is also slightly closer to the simulation result than the previous analysis result is, especially in heavier offered load.     

Numerical Stability Verification of a Two-Dimensional Time-Dependent Nonlinear Shallow Water System Using Multidimensional Wave Digital Filtering Network

This paper aims to study the stability effects of a two-dimensional time-dependent nonlinear shallow water (NLSW) system based on the concordance analysis of necessary and sufficient conditions derived from a multidimensional wave digital filtering (MDWDF) network. Approximating the differential equations used to describe elements of a MD passive electrical circuit by grid-based difference equations, the satisfactory Courant–Friedrichs–Levy condition usually known to be necessary are derived with various initial conditions to provide theoretical support for the existence of a MD passive dynamical system and thus stability of the discrete equivalent. Together with the evaluation of the system’s energy and hence solution error propagation that both arise directly and sufficiently to the stability of MDWDF networks, the numerical convergence of the network can be fully established. As a consequence, all instability related aspects in relation to computational errors and overflow corrections are fully excluded leading to uniquely a high degree of robustness of MDWDF architecture. Feasible comparisons are made with a finite element method implemented in the COMSOL Multiphysics to confirm the verification process.     

Diffusiophoresis of a soft spherical particle along the axis of a cylindrical microchannel

The diffusiophoresis of a soft particle is modeled theoretically by considering a soft sphere moving along the axis of a cylindrical microchannel. This geometry allows us to examine simultaneously the boundary effect and the nature of a particle on its diffusiophoretic behavior. The soft particle, which comprises a rigid core and an ion-penetrable layer, is capable of simulating biocolloids such as cells and particles covered by an artificial membrane layer. The results of numerical simulation reveal that due to its specific structure, the diffusiophoretic behavior of a soft particle is quite different from that of a rigid particle. The influence of the cylindrical microchannel on the diffusiophoretic behavior of the particle is also very different from that of other geometries considered in the literature. We show that, in addition to the effect of double-layer polarization, the effect of electrophoresis, and the electrical interaction between the coions outside the double layer and the particle, the nature of the soft particle can also influence both quantitatively and qualitatively its diffusiophoretic behavior. Several interesting results are observed, providing valuable reference for both the design of a diffusiophoresis device and the interpretation of the relevant experimental data.     

FACE: Fine-tuned Architecture Codesign Environment for ASIP Development

High-performance, reliable, and robust products with a short development schedule are general design aims. FACE was developed to achieve these goals, including the organization of a design flow, a frequency-driven information analyzer, compiler techniques (code generator and instruction optimization), and a hierarchical object design library. This paper explores the design space of a retargetable compiler and a reconfigurable hardware, which combine both software and hardware reprogrammability. The environment, FACE, we have developed allows us to quickly move the functions between software and hardware in a state of flux. Finally, it generates the application specific integrated processor (ASIP) and a compiler for the new ASIP architecture. The case study is considered which demonstrates the efficiency in ASIP design of FACE.     

New structure transcutaneous transformer for totally implantableartificial heart system

A new structure transcutaneous transformer for a totally implantable artificial heart is presented which has a high coupling coefficient and transmission efficiency. Experimental results indicate that it is possible to transmit an electrical energy of 20 W transcutaneously with a maximum efficiency of more than 90%