Preliminary Study for the Establishment of DC Charge Calibration Facility at CSIR-NPL Using Charged Capacitance Source

The present paper reports the details of the preliminary study towards the establishment of DC charge calibration facility at CSIR-NPL down to pico-coulomb ranges using charged capacitance source. The work involves the development of an automated electric charge generation and measurement setup using automation measurement program developed in LabVIEW programming environment. Charge measurements down to 100 pC have been performed with very good measurement accuracy and the expanded uncertainty has been evaluated as per ISO GUM document.     

Determination of filler content in rice husk ash and wood-based composites by thermogravimetric analysis

Three new types of fillers for polypropylene are investigated. The first two were derived from burnt rice husk ash (RHA), whereas the third, a wood-based filler, was processed from oil palm trunk. One important characterization of the composites involves the checking for the actual filler content and filler distribution within the matrix. An analytical technique is described here for computation of the filler content in the composites based on a simple expression derives from thermogravimetric analyses. For filler with volatiles such as the black RHA, the derived expression was p _f = 106 ( r _b / m _c ), and for easily burnt fillers (wood-based), the expression was p _f = 156 ( m _d / m _c ). The technique has shown good agreement and consistency between analyzed and actual filler contents and a uniform filler distribution within the polypropylene matrix. © 1994 John Wiley & Sons, Inc.     

Fungal resistance of densified ammonia-impregnated oil palm stem

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Grafting of methacrylic acid to loomastate viscose fabric using KMnO4/NaClO2 system

Graft polymerization of methacrylic acid (MAA) to loomstate viscose fabric (greige fabric) using KMnO₄/NaClO₂ system was studied. Residual thiocarbonate and/or sizing materials on the fabric as well as presence of NaClO₂ act in favor of primary radical formation which, in turn, accelerate formation of cellulose macroradicals capable of initiating grafting. The polymerization reaction was studied with respect to polymer yield, graft yield, homopolymer, total conversion, and graft efficiency. The magnitude of each of these characteristics was found to depend upon parameters such as concentrations of KMnO₄, NaClO₂, and MAA as well as liquor ratio, reaction time, and temperature of polymerization. By and large all these parameters enhance the polymerization process with the exception of the liquor ratio. A reaction mechanism for the polymerization reaction is also reported. © 1995 John Wiley & Sons, Inc.     

Engineering education in rapidly industrialising Malaysia

Malaysia aspires to be a fully industrialised nation by the year 2020. This has brought about a shift from what was predominantly an agriculturally-based economy to a rapidly expanding manufacturing-based one. This shift has brought to the fore the need for a large pool of people, especially engineers, with a strong base in science and technology. The government has embarked on various programmes to launch the bandwagon. This paper describes some of these programmes and measures that have been implemented or are now being planned, with a focus on engineering and engineering education at the tertiary level. Some recommendations are also made for supplementing the programmes already in place     

On the optimal replenishment schedule for an inventory system with deteriorating items and time-varying demand and production rates

In this paper, we present an exact method for finding the optimal replenishment schedule for an inventory system with deteriorating items, and in which demand and production rates are allowed to vary over a finite planning horizon. A numerical example is presented to illustrate the method.     

Production of a diacylglycerol-enriched palm olein using lipase-catalyzed partial hydrolysis: Optimization using response surface methodology

Partial hydrolysis using Lipozyme RMIM lipase in a solvent-free system was used to produce a diacylglycerol (DAG)-enriched palm olein. Response surface methodology (RSM) was applied to model and optimize the reaction conditions namely water content (30–70 wt% of enzyme mass), enzyme load (5–15 wt% of oil mass), reaction temperature (45–85 °C) and reaction time (6–16 h). Well fitting models were successfully established for both DAG yield (R² = 0.8788) and unhydrolysed triacylglycerol (TAG) (R² = 0.8653) through multiple linear regressions with backward elimination. Chi-square test indicated that there were no significant (P > 0.05) differences between the observed and predicted values for both models. All reaction conditions had positive effects on DAG yield and negative effects on unhydrolysed TAG. Optimal reaction conditions were: 50 wt% water content, 10 wt% enzyme load, 65°C of reaction temperature and 12 h of reaction time. The process was further up-scaled to a 9 kg production in a continuous packed bed bioreactor. Results indicated that upscaling was possible with a similar DAG yield (32 wt%) as in lab scale. Purification of the DAG oil using short path distillation yielded a DAG-enriched palm olein with 60 wt% DAG and 40 wt% TAG which is suitable for margarine, spread or shortening applications.     

Optimization and sensitivity of prestressed concrete beams

This paper is concerned with the optimum design of prestressed concrete beams. Both minimum weight and minimum cost optimization formulations are given for simply supported beams having three different sections. Sensitivity of the optimum designs, with respect to various design parameters, are also discussed. The formulation is programmed for interactive use on micro-computers. An example is given and results are discussed.     

A study of switching overvoltages on composite feeders—Line-cable feeders

This study is concerned with the overvoltages produced as a result of switching operations on composite feeders, this is when a circuit-breaker closes its contacts at the peak values of the applied voltage. Line-cable feeders are considered in the study. The means by which such overvoltages can be reduced are also included. Also, the effects of system parameters and factors on the initial voltage applied and accompanied overvoltages are covered.     

A functional approach to redesign

This paper describes a methodology to assist in the identification of possible conceptual design variants during redesign. The approach is based on functional reasoning and involves: (1) the structural and functional analysis of an existing design; (2) the production of abstract representations of functions and design entities using conceptual graphs; and (3) design interrogation based on a functional tree approach. The research reported in this paper also focuses on the definition and the representation of elementary mechanical functions. Extended Backus-Naur Form (EBNF) notations are used to structure in a computable form, the relevant information (or design knowledge) conceptualised in either the conceptual graphs or the functional trees. EBNF syntax is also used to formulate rules which aid the partial automation of the reasoning process. The EBNF notations can be mapped to any programming language. A diaphragm valve is used as a case study to demonstrate the approach.