Peak Load Management in Electrolytic Process Industries

Electrolytic process, employed for manufacturing basic chemicals like caustic soda and chlorine, is highly energy intensive. Due to escalating costs of fossil fuels and capacity addition, the electricity cost has been increasing for the last few decades. Electricity intensive industries find it very difficult to cope up with higher electricity charges particularly with time-of-use (TOU) tariffs implemented by the utilities with the objective of flattening the load curve. Load management programs focusing on reduced electricity use at the time of utility's peak demand, by strategic load shifting, is a viable option for industries to reduce their electricity cost. This paper presents an optimization model and formulation for load management for electrolytic process industries. The formulation utilizes mixed integer nonlinear programming (MINLP) technique for minimizing the electricity cost and reducing the peak demand, by rescheduling the loads, satisfying the industry constraints. The case study of a typical caustic-chlorine plant shows that a reduction of about 19% in the peak demand with a corresponding saving of about 3.9% in the electricity cost is possible with the optimal load scheduling under TOU tariff.     

Intelligent Interactive Tutoring Systemfor Engineering Mechanics

Engineering education has traditionally been imparted through the lecture-tutorial-laboratory paradigm. Education technology in the last few years has tried to make teaching more effective by supplementing the chalkboard teaching with audiovisual aids like overhead∕slide projectors and videos. These are, however, passive teaching tools. Recent advancement in computer multimedia has brought in a new teaching medium. Multimedia education has several advantages; most noticeably, the instructions can be interactive and self-paced to meet the needs of each individual student. The writers have developed an Intelligent Interactive Tutoring System for engineering mechanics for the first-year engineering students at the Nanyang Technological University, Singapore. The main objective of this system was to supplement classroom teaching via intelligent interaction with the computer-based tutoring system. This system is designed to be a self-paced virtual tutor with intelligent, user-friendly interactions. It is intended to be different from the many commercially available computerized textbooks. The prototype system was tried out with about 200 students who had earlier failed the course in the first semester and repeated it in the second semester of academic year 1997–1998. The system received good response from the students. The full version was implemented on the Nanyang Technological University Intranet and the Internet for use by the regular class of more than 1,600 students in both academic years 1998–1999 and 1999–2000.     

Ultra‐selective epoxidation of styrene on pure Cu{111} and the effects of Cs promotion

Styrene undergoes efficient epoxidation to styrene epoxide on the Cu{111} surface. At the optimum condition (Θ_o = 0.03 ML) ∼20% of the styrene is converted to the epoxide with almost 100% selectivity. Comparison with Ag{111} shows that the epoxidation activity and selectivity of Cu greatly exceed those of Ag. Incipient oxidation of the Cu{111} surface does not suppress the adsorption of styrene, but the oxidised metal is catalytically inert. Submonolayer amounts of Cs enhance styrene uptake and increase conversion to the epoxide without adversely affecting epoxidation selectivity. This effect is due to inhibition of Cu oxidation by Cs. Our findings are discussed in the light of current understanding of Ag‐catalysed alkene epoxidation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Proposed high speed packet switch for broadband integrated networks

The design of a high speed, broadband packet switch with two priority levels for application in integrated voice/data networks is presented. The packet switch can efficiently cope with 128 byte packets converging on it from eight 140 Mbit/s dynamic time division multiplexed fibre optic links. The packet switch throughput varies with the load and traffic composition, and the delay experienced by voice and data packets is within 300 μs and 3 ms, respectively. The design is implemented by task-sharing in a multi-processor configuration. The design of the packet switch, including its subsystems, is detailed here.     

Surface structural investigations on (100) and (110) faces of flux-grown lanthanum borate crystals

Results of topographical studies carried out on (100) and (110) faces of lanthanum borate crystals grown from the PbO-B₂O₃ flux system are illustrated and discussed. The habit faces display the formation of cavities, microcrystals, elliptical etch pits, elliptical hillocks, circular hillocks and irregular structures. Also described are a various number of elevated structures identified as impurity phases. Energy dispersive X-ray (EDAX) studies have confirmed that these impurity phases in the growth of lanthanum borate (LaBO₃) crystals are enriched by lead (Pb). The habit faces also exhibit some elevated regions which are reported to be more imperfect in comparison with others. It is inferred that independent growth on the habit faces has taken place during the last stage of crystal growth by a two-dimensional nucleation mechanism.     

Stochastic behaviour of man-machine systems operating under different weather conditions

This paper presents two mathematical models to predict the performance of the man—machine systems under different weather conditions. The operator may be in good or poor physical condition which also affects the performance of the system. Failure rate of the system, rate of change of weather conditions as well as rate of change of physical conditions of the operator are assumed to be constant while the repair time distributions are general. Regenerative technique in MRP is applied to obtain several reliability characteristics of interest.     

Integrated Front-End Radar Receivers at Ka-Band

This paper describes the Integrated Finline Front-end Radar Receivers at Ka-Band. The Front-receivers developed for Radar applications include combining of finline components on a single MIC substrate with various planar transmission lines. The integrated systems so developed have better noise figure and control over phase and gain imbalances as compared to discrete component systems. Two types of Integrated Front-ends Radar receivers are described here. The developed systems are highly compact and reliable.