We report a new design and operation of a microelectromechanical systems (MEMS) differential scanning calorimeter (DSC) for heat-capacity measurements. The sensor consists of a 500-nm silicon nitride membrane supported by four bridges on a silicon wafer. On one side of the membrane, a serpentineshaped platinum layer is deposited and used as both a resistive heater and a thermometer during the DSC measurement. This MEMS design can provide a self-alignment between the DSC cell and the material to be analyzed in order to prevent its deposition on the sloping side walls of the silicon frame. According to FEM calculations, the system exhibits good thermal isolation and high uniformities in the temperature field in the sensing area of the device. To evaluate the use of this calorimetric device for liquid samples, we measure the heat of vaporization of nanoliter-scale water droplets with high preciseness using the calorimeter in both scanning and heat conduction modes.[ 2008-0288]Index Terms-Calorimetry, heat capacity, microelectromechanical systems (MEMS).

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The wire rod mill of the Ajaokuta Steel Company Limited produces coils, wire rods and re-bars of different sizes. Without the furnace hangers, it will be difficult for the mill to continue to operate. This paper describes the production of furnace roof hangers that are required for re-heating furnace using the spheroidal graphite iron (SGI), highlighting the sand-casting process, charge calculation, and the chemical compositions. The facilities within the foundry shop of the steel company are used to produce furnace roof hangers. The available materials used for the casting of the hangers are the pig iron, scrap ends, foundry returns and magnesium. The process of production was performed through the reheating furnace for the heating of 120 m x 120 m x 120 m billets. One ton induction furnace of low frequency was used as the melting vessel. Also, 6 kg of magnesium was introduced in the ladle before the liquid metal was teemed into it. A Spectro analytical instrument was used to determine the chemical compositions of the materials before and after the casting processes. The analysis of the chemical compositions of produced sample of SGI are presented and discussed.

Statistical Quality Control (SQC) analysis deals with quantitative data; it is also a scientific method of analyzing masses of numerical data so as to summarize the essential features and relationship of data in order to generalize from the analysis pattern behaviour, particular outcome or future tendencies. This research work focused on the use of statistical quality control to determine the behaviours of the determined chemical compositions of rolled products from the Light Section Mill of the Rolling Mills of the Ajaokuta Steel Company Limited with a view to detecting and eliminating non-random (sporadic) variations in production process. The process monitored the performance of the chemical compositions of rolled products of medium carbon steel on a daily basis during the period of production from 29/04/06 to 29/05/06 for the production of rods from the Light Section Mill (LSM). The analyzed samples and data collected for critical characteristics were determined to ascertain if they shifted away from the purely random pattern (specified compositions). Ten samples were collected from the rolled products from the mill and were analyzed with a SPECTRO Analytical Instrument in the Quality Control and Materials Analysis in the Foundry Shop of the company, where the chemical compositions were determined as shown on the tables and they were also used to plot graphs for better understanding. Two control charts ( x and R ) were used to determine the performance and to indicate if the process remained in control and whether there are variations, these will serve as early warning system for information to the production engineers, the quality control officers and management of the mill that something odd has probably happened to the production process.

Heavy metals pollution potential in National Iron Ore Mining Company, Itakpe was investigated. Two mining sites located at the east mining pits such as M3O, which is 370 m above sea level and M2O, which is 350 m above sea level were studied.  Sequential extraction techniques was utilised to examine the distribution effect of the heavy metals pollution potential on the environment. Twelve representative (six-soil, two-sediment, two-plant and two-water) samples were collected, pre-treated and prepared for this study. The atomic absorption spectrometer was used to analyse the concentration of the metals after the sequential and single-stage extractions were determined. Results showed that Chromium, Arsenic, Cadmium and Copper are more bioavailable in the study area than Lead and Iron. This findings indicate that human, animals and plants are exposed to toxic elements (metals and metalloids).