This paper reports on a simple approach of determining the ability of a transparent material, such as cellophane to rotate the direction of polarization of a light beam. In order to determine the birefringence of such a material, a Mach-Zehnder interferometer is used to generate interference patterns when the cellophane sheet is mounted on one arm such as to intercept a portion of the laser beam. The recorded interferograms show a phase shift which is calculated to be 0.98π radians. By rotating the cellophane sheet on the object beam, the fringe separation is measured for different angles and the values used to calculate the ordinary and extraordinary refractive indices as 1.4721 ± 0.0002 and 1.4680 ± 0.0002 respectively at 632.8 nm wavelength. A surface error of approximately λ/16 (peak to valley) is measured from the recorded interferograms. Because of its sufficient birefringence and small thickness of 24 µm, cellophane can be used to fabricate special polarization pupil masks by cutting and aligning different cellophane structures appropriately.

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In this work the impact of backscattered energetic atoms on film growth in reactive sputtering of CrN x (x 1) is manifested. We use film and plasma characterization techniques, as well as simulations in order to study the dynamics of the target-discharge-film interactions. The results show that the primary bombarding species of the growing film are N + 2 plasma ions, which are neutralized and backscattered by the target in the form of atomic N. It is shown that the backscattered N atoms have energies which are significantly higher than those of other bombarding species, i.e. the backscattered Ar atoms, the sputtered atoms and the plasma ions. Moreover, it is found that CrN films exhibit compressive stresses of 2.6 GPa and a density close to the bulk value. We attribute these properties to the bombardment by backscattered energetic atoms, in particular N. Pure Cr films are also studied for reference.

The accurate reading of a customer water-meter is important as it is the main revenue base for the water authorities. The traditional data collection process is still common in developing countries despite the inherent inefficiency, inaccuracy and labour intensity. A solution to improvement could be based on sensor and communication technology. In this research an automatic water meter reading system has been designed, fabricated and tested. It consists of G1/2 flow sensor, PIC18F4550 microcontroller, LCD, GSM module and solenoid control valve. When water flows through flow sensor, pulses are generated which are converted to volumetric flow using PIC18F550.The LCD displays the readings which are sent automatically to the Water Company as an SMS for billing purposes after a specified period. The proposed system is cost effective and gives automated water meter reading at high accuracy.

A phase change alloy has been synthesized and characterized. The reversible phase transitions between amorphous and crystalline states of SnSe 4 films have been studied using variable electrical pulses and X-ray diffraction. Temperature dependent sheet resistance measurements have shown two distinct resistivity states of more than two orders of magnitude. This high electrical contrast makes the alloy suitable for nonvolatile phase change memory applications. Xray diffraction has attributed the large electrical contrast to an amorphous-crystalline phase transition. The nonvolatile memory cells have been fabricated using a simple sandwich structure (metal/chalcogenide thin film/metal). A threshold voltage of 3.71 V has been determined for this phase change random access memory cell. Memory switching was initiated using the voltage pulses of 3.71 V, 90 ns, 1.3 V and 26 μs, for the crystallization and amorphization process, respectively.