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Concrete being an important material for construction of various structures has severe demand in the present trend of construction industry. Aggregate occupies the major quantity (70% approx.) of concrete based on which characteristics like compressive strength and porosity are controlled. The present usage of aggregate for construction is resulting in the depletion of the natural resources as well as it is showing a great impact on the environment. The work is to focus on the strength characteristics of concrete using coconut shell as an alternative material obtained from coconut processing units. Based on earlier studies a nominal amount of 30% replacement of natural coarse aggregate with coconut shell has been fixed. 'Alccofine' is used as a mineral admixture by replacing cement at various proportions in order to supplement the loss of strength. Tests have been carried out to find out the dry density, wet density and compressive strength. Comparison of the results show that the 30CS A8 (M4) achieving less density without compromising the strength.

This paper presents a robust, low power MEMS igniter built using low pressure chemical vapor deposited (LPCVD) polycrystalline Silicon Carbide films. The MEMS igniter design is based on a 5 µm thick, low stress membrane composed of doped and undoped SiC layers making up the resistive heaters and passivation layer respectively. Experimental tests using an optical pyrometer to measure temperature indicate that this igniter can achieve temperatures beyond 1400°C, with less than 10 W power input, and a time response of less than 0.1 sec. Reliability tests were performed to characterize the igniter behavior as a function of time and determine the lifetime of the devices. Lifetime of the igniter at temperatures greater than 1300°C was limited due to the growth of unstable crystobalite oxide layers resulting in membrane fracture. Reliability significantly improved when operation of the igniter was limited to temperatures below 1100°C.

We present a design, process flow and packaging scheme for a novel 3-Dimensional capacitive MEMS pressure sensor [1]. These sensors present a paradigm shift in pressure sensor technology. They contain an array of vertical diaphragms perpendicular to the wafer plane where each pair of diaphragms requires orders of magnitude lower footprint than traditional in-plane sensors. The sensor can be arrayed or scaled up for increased sensitivity and can be absolute, gage or differential. Fabrication requires 2-4 masks depending on process flow and has been greatly simplified, without reduction in performance, for high yield and low cost. Multiple geometries have been modeled with sensitivities reaching several fF/kPa and temperature characteristics better than conventional devices. Pressure and electrical ports are individually interchangeable between front and back sides. This allows for a simple design that has only Si facing the sensing environment and the electrical connections on the backside.