A structured procedure for analysis and design of order pick systems

We present a structured procedure for order pick system (OPS) analysis and design that has been established on literature review and interviews with and presentations to OPS experts. In particular, we attempt to include the thinking processes that occur between OPS designers and owners. The design procedure and related issues are discussed in the order of input, selection, and evaluation stages.     

Precipitation behavior of σ phase in fusion zone of dissimilar stainless steel welds during multi-pass GTAW process

The purpose of this study is to investigate the precipitation characteristics of σ phase in the fusion zone of stainless steel welds at various welding passes during a tungsten are welding (GTAW) process. The morphology, quantity, and chemical composition of the δ-ferrite and σ phase were analyzed using optical microscopy (OM), a ferritscope (FS), a X-ray diffractometer (XRD), scanning electron microscopy (SEM), an electron probe micro-analyzer (EPMA), and a wavelength dispersive spectrometer (WDS), respectively. Massive δ-ferrite was observed in the fusion zone of the first pass welds during welding of dissimilar stainless steels. The σ phase precipitated at the inner δ-ferrite particles and decreased δ-ferrite content during the third pass welding. The σ and δ phases can be stabilized by Si element, which promoted the phase transformation of σ→ϱ+λ₂ in the fusion zone of the third pass welds. It was found that the σ phase was a Fe−Cr−Si intermetallic compound found in the fusion zone of the third pass welds during multi-pass welding.     

Anomalous variations of OFF-State leakage current in poly-Si TFTunder static stress

Studies the anomalous variations of the OFF-state leakage current (I_OFF) in n-channel poly-Si thin-film transistors (TFTs) under static stress. The dominant mechanisms for the anomalous I_OFF can be attributed to (1) I_OFF increases due to channel hot electrons trapping at the gate oxide/channel interface and silicon grain boundaries and (2) I_OFF decreases due to hot holes accumulated/trapped near the channel/bottom oxide interface near the source region. Under the stress of high drain bias, serious impact ionization effect will occur to generate hot electrons and hot holes near the drain region. Some of holes will be injected into the gate oxide due to the vertical field (~(V_Gstress V_Dstress)/T _OX) near the drain and the others will be migrated from drain to source along the channel due to lateral electric field (~V_Dstress/L_CH)     

A new method for calculating loss coefficients [of power systems]

A method is proposed which avoids many limitations associated with traditional B-coefficient loss coefficient calculation. The proposed method, unlike the traditional B-coefficient method, is very fast and can handle line outages. The method utilizes network sensitivity factors which are established from DC load flow solutions, Line outage distribution factors (ODFs) are formulated using changes in network power generations to simulate the outaged line from the network. The method avoids the use of complicated reference frame transformations based upon Kron's tenser analysis. The necessity of data normalization used in least squares and the evaluation of the slope of &thetas;_j versus PG_n is not necessary with the proposed method. Using IEEE standard 14-bus and 30-bus systems, the method's results are compared against results obtained from an AC load flow program (LFED). The method's solution speed is compared to that of the LFED method, the base case database method and the conventional B-coefficient method based on A_jn-factor. The proposed method is easy to implement and, when compared to other methods, has exhibited good accuracy and rapid execution times. The method is well suited to online dispatch applications     

Optimization of a schottky barrier mixer diode in the submillimeter wave region

We have designed a mixer Schottky barrier diode (SBD) for use in the submillimeter wave region with a structure optimized for minimum noise temperature. The dependence of mixer noise temperature upon thickness and doping density of the epitaxial layer and diode diameter of SBDs was simulated within the framework of existing theories. Special care was taken to formulate the SBD current-voltage and capacitance-voltage relations in a way that correctly describes the behavior of real SBDs.     

Comparison of protein adsorption isotherms and uptake rates in preparative cation-exchange materials

Adsorption isotherms and effective diffusivities of lysozyme in a set of six preparative cation-exchange stationary phases were determined from batch uptake data in a stirred vessel. Both a pore diffusion and a homogeneous diffusion model were used in estimating diffusivities, with the isotherms fitted to a non-Langmuirian analytical isotherm equation. The capacities inferred from the isotherms are found to be correlated with the surface area accessible to lysozyme, the effective surface concentrations obtained being in agreement with values measured by different methods in various non-chromatographic systems. The pore diffusivities show systematic trends with protein and salt concentration, and effects of pore size and connectivity are also evident. Some trends in the homogeneous diffusivities are quite different to those in the pore diffusivities, but these differences largely disappear when the homogeneous diffusivities are rescaled to account for adsorption equilibrium behavior. Additional information is required to elucidate further the mechanisms of coupled diffusion and adsorption in stationary phases.     

GaInP/GaAs HBTs for high-speed integrated circuit applications

The use of GaInP/GaAs heterojunction bipolar transistors (HBTs) for integrated circuit applications is demonstrated. The discrete devices fabricated showed excellent DC characteristics with low V_ce offset voltage and very low temperature sensitivity of the current gain. For a non-self-aligned device with a 3-μm×1.4-μm emitter area, f_T was extrapolated to 45 GHz and f_max was extrapolated to 70 GHz. The measured 1/f noise level was 20 dB better than that of AlGaAs HBTs and comparable to that of low-noise silicon bipolar junction transistors, and the noise bump (Lorentzian component) was not observed. The fabricated gain block circuits showed 8.5 dB gain with a 3-dB bandwidth of 12 GHz, and static frequency dividers (divide by 4) were operable up to 8 GHz     

HAR-sEMG: A Dataset for Human Activity Recognition on Lower-Limb sEMG

Knowledge and Information Systems - In the past decade, human activity recognition (HAR) has grown in popularity due to its applications in security and entertainment. As recent years have...