Zone-branch reliability methodology applied to Gold Book standard network

There is a need recognized in the power industry to identify and utilize a standard tool or a set of tools to analyze the reliability of industrial and commercial power systems. Historically, the reliability results of different reliability methodologies varied significantly and comparisons were extremely difficult. The Reliability Analysis Technique Working Group of the Gold Book (i.e., IEEE Std. 493) developed a standard network to enable comparison of analytical techniques. This paper identifies the different analysis techniques currently available. This paper is the second of a series of papers applying the zone-branch methodology to the Gold Book standard network configuration. Two case studies are presented for different network operating practices. Future papers applying these different techniques to the same Gold Book standard network configuration will be presented and the results compared to determine accuracy of these analytical techniques.     

Synthesis and Characterization of Silicone-Based Surfactants as Anti-Foaming Agents

Silicone-based amphiphilic surfactants were synthesized as anti-foaming agents through a polycondensation reaction between chlorine-terminated polysiloxane and polyethers. Poly(ethylene glycol) (PEG) and poly(propylene glycol) of different molecular weights were used. The structures of these tri-block co-polymers were characterized by FTIR, ¹H NMR and ESI–MS analysis. Surface tension, foam height and foam destruction properties of these co-polymers were determined. Spectroscopic analysis confirmed that bonding of polyether to polysiloxane was successful and two types of different tri-block co-polymers were obtained. The anti-foaming efficiency of these co-polymers tended to increase with an increase in the hydrophilic character of the co-polymer chains. The synthesized tri-block co-polymers, which can be used as anti-foaming agents in paper-coating applications of poly(vinyl acetate-co-butyl acrylate) latexes, showed low surface tension values, fast liquid drainage and efficient foam destruction. PEG 200-b-PDMS-b-PEG 200 was determined to be the most efficient anti-foaming agent among all co-polymers synthesized.     

Plasma-induced adhesion improvement of cotton/polypropylene-laminated fabrics

In this study, improvement in the adhesion strength of plasma-pretreated and laminated cotton/polypropylene (PP) fabrics using acrylic-based adhesive was investigated. Low-temperature, low-pressure oxygen plasma was utilized for surface modification of cotton/PP-laminated fabrics. Water absorption time was measured on plasma-treated cotton fabrics at different plasma power and treatment time conditions. The plasma conditions providing the fastest liquid absorption on the surface were selected and applied during plasma pretreatments. Surface wettability increased with increasing plasma power and plasma exposure time. Plasma-induced surface morphology changes were observed via Scanning Electron Microscope (SEM) images. X-ray Photoelectron Spectroscopy (XPS) analysis showed that oxygen content on the surface increased with plasma treatment, which contributed to the surface polarity and hydrophilicity. Peel bond strength results of untreated and plasma-treated samples were analyzed to determine the effect of plasma pretreatment process. Adhesion strength values of laminated samples, before washing and after 40 wash cycles, were determined by peel bond strength tests. Before washing, adhesion strength of plasma pre-treated, laminated samples was 28–60% higher than that of untreated laminated fabrics. After 40 wash cycles, adhesion strength of plasma pre-treated and laminated samples was about 40–69% higher than the untreated laminated fabrics. Peel bond strength values decreased with the increased number of wash cycles. Plasma pretreatment enhanced both the adhesion strength and washing resistance of laminated samples.     

APPLICATION OF MULTIVARIABLE NONLINEAR ADAPTIVE GENERIC MODEL CONTROL TO A PACKED DISTILLATION COLUMN

Nonlinear adaptive generic model control and self-tuning PID control systems were applied to control the top and bottom product temperature of a packed distillation column separating methanol-water mixture. In the first control algorithm, an adaptive generic model control (AGMC) structure was proposed for dual temperature control of the system. In the second control algorithm, nonlinear self tuning PID (NLSTPID) control based on pole-placement technique was used to control the same system. For NLSTPID control purposes pseudo random binary sequence (PRBS) signal and recursive identification algorithm were used to estimate the relevant parameters of a polynomial NARMAX model. In this work, real-time application has been carried out. In both dynamic and control studies, perturbations in feed composition were utilized as the disturbance, and the reboiler heat duty and the reflux ratio were selected as the manipulated variables. The control performances have been obtained by using ISE and, in general, AGMC results were better than those of the STPID control algorithm.     

Measuring the frequency response of gigabit chip photodiodes

We describe a calibration and measurement procedure for determining the intrinsic frequency response of gigabit chip photodiodes embedded in simple test fixtures. The procedure is unique because we make the measurements in the time domain using a calibrated oscilloscope, and we then apply frequency-domain mismatch corrections to remove the effects of the fixture, bias T, and cables from the measurements. We demonstrate the procedure on photodiodes with an active region of approximately 150-μm diameter excited by short 800-nm wavelength optical pulses     

The VB5 interface

The VB5 interface is an ATM-based broadband interface at the V reference point, the interface between a user access and a service node (SN), also known as the SNI (service node interface) within the ITU-T. The B-ISDN architectural model allows for a number of different user accesses, such as straightforward digital sections and simple multiplexers, but it is anticipated that the most frequent implementation, particularly for mass deployment, will be via a broadband access network (AN) with VB5 interfaces.The VB5 interface is specified in a similar way to its narrowband cousin V5, in two variants – VB5.1, which supports allocation of resources via the management system, and VB5.2, which adds a mechanism for allocating AN resources under the control of the SN, enabling call-by-call concentration in the AN. This paper describes the background to the development of VB5 and explains the two variants VB5.1 and VB5.2.     

Hot water decontamination of beef carcasses for reduction of initial bacterial numbers

Areas on freshly slaughtered beef carcasses were sprayed with hot (95°C), sterilized, distilled water in order to elevate carcass surface temperature to 82°C. A significant (P < 0·05) reduction in bacterial numbers was observed between control (prespray) and hot water treated carcass surfaces. These results indicate that microbial decontamination of beef carcasses with hot water will be effective if an approprite spraying apparatus is used.     

Parallel distributed seismic migration

We report significant speed-up for seismic migration running in parallel on networkconnected IBM RISC/6000 workstations, A sustained performance of 15 MFLOP is obtained on a single-entry-level model 320, and speed-ups as high as 5 are obtained for six workstations connected by Ethernet or token ring. Our parallel software uses remote procedure calls provided by NCS (Network Computing System). We have run over a dozen workstations in parallel, but speed-ups become limited by network data rate. Fiber-optic communication should allow much greater speed-ups, and we describe our preliminary results with the fiberoptic serial link adapter of the RISC/6000. We also present a simple theoretical model that agrees well with our measurements and allows speed-up to be predicted from a knowledge of the ratio of computation to communication, which can be determined empirically before the program is parallellzed. We conclude with a brief discussion of alternative software approaches and programming models for network-connected parallel systems. In particular, our program was recently ported to PVM and Linda, and preliminary measurements yield speed-ups very close to those described here.