654 research outputs found
Sort by
Fiber Optic Technique for Sensing Temperature, Contamination and Layer Thickness of Immiscible Liquids
No full textIn accordance with the principle of the technique based on Fresnel reflection, reflectivity of a dielectric surface depends on the difference of refractive indices of the surface and the surrounding medium, and the reflection coefficient is defined as the ratio of the reflected light power to the incident light power. In the investigations reported, the amount of back reflected light at one of the output ports of a 2 × 2 single-mode optical-fiber coupler due to Fresnel reflection was monitored by means of a high sensitivity
Design, fabrication and performance of a fiber optic flowmeter for transparent fluids.
No full textThe concept, design, fabrication and experimental implementation of a fiber optic flowmeter for transparent fluids is reported. The device operates on the principle of light intensity modulation due to angular misalignment of multimode optical fibers caused by drag of a streamline flow. The working laboratory model of the flowmeter was tested in a water flow line and the performance studied was found to be satisfactory. It offers the possibility for remote monitoring of flow of non-corrosive and transparent fluids in various scientific and industrial applications
Training needs assessment of engineering students: A Case Study
No full textTraining of engineering students in an industrial environment is an alternative to projects undertaken within the institute. The approach becomes more challenging as it puts them in a new environment with the generally accepted goal of improving their application skills. To implement such a scheme requires a coherent effort from students, faculty members and industry supervisors. In this case study, we propose a model for making formal need assessment of engineering students' training which [then] forms the basis of [the training's] evaluation and effectiveness. The [need] assessment is [outlined in terms of] inherent attributes, generic attributes, technical skills and students' basic needs of training. Finally, the students' reaction evaluation and relevance [of training] to job prospects are presented
Plasma etch models based on different plasma chemistry for micro-electro-mechanical-systems application.
No full textThe suitability of different plasma etch models based on various plasma chemistry has been evaluated for the fabrication of micro-mechanical structures and micro-electro-mechanical systems. Different etch models have been described for silicon etching based on fluorine and chlorine chemistry and the mechanisms involved in SiO2 etching. Conventional planar reactive ion etching systems have been utilized for the etching of SiO2 and silicon based on fluorine and chlorine etch models. Fluorine containing gases such as CHF3 in combination with Ar have been used for SiO2 etching and achieved nearly vertical sidewalls with smooth bottom surface. Gas mixtures such as SF6/O2 at low substrate temperatures and Cl2/BCl3 have been used for silicon etching and sidewall passivation techniques have been employed to achieve vertical sidewalls. The usefulness of chlorine chemistry using BCl3 gas chopping technique for the fabrication of high aspect ratio structures has been demonstrated
An experimental approach for mould preparation and moulding technique of fresnel lenses
No full textAn experimental fabrication technique of Fresnel lens master mould and the method adopted for moulding plastic Fresnel lenses is described. Fresnel lenses have concentric prismatic grooves of varying depths and angles. Itis a difficult process to obtain turned metallic moulds for moulding such type of bigger size lenses. Fabrication of Fresnel lens master mould by replication technique is an attractive alternative. This paper describe how the master mould has been fabricated by copper deposition process. The selection of plastic material for lenses based on optical properties has also been enumerated
Development of a Microprocessor based Biochemical Sampler
No full textModern medicine requires patients to be treated on the basis of precise data, which are often obtained from electronic equipment. An inexpensive and portable microprocessor-based sampler developed by the authors is described. It is comprised of the following units: sample plate assembly, probe-drive linkage system, wash fluid receptacle, timing system and 8085A microprocessor
Implementation of hop field neural network model in the area of associative memory
No full textThe human memory has its ability to learn about many new things without necessarily forgetting them, learnt in the past. Exactly the same can be thought about the Artificial
Neural Networks system, How can its learning system remain responsive in response to significant input, yet remain stable in response to irrelevant input? How does the system
retain previously learnt information while continuing to learn about new information. This paper attempts to address the theory and implementation of Hopfield Neural Network in
the area of Associative Memory(AM). There are three types of Associative Memory: Hetero-associative Memory, Interpolative Memory and Auto-associative Memory. Human
memory works on the basis of partial knowledge of its contents and or association with other information. This may be called as “Content-Addressible Memory”. We provide a
small part of input pattern to the system, the net or by self excitation the whole pattern will be regenerated. Neural network simulations have allowed researchers to study how and under what conditions such studies are that associative memory can do better in the presence of a certain level of internal noise or with certain level of forgetfulness, The system, distributed as one memory is distributed over many synapses, superimposed because one synapse can be involved in several memories and robust because altering a few synapses degrade the performance by very little
Design of a patterned substrate for gas sensor applications
No full textGas sensors based on semiconducting oxides can be used for the detection of combustible and noxious gases in air. Their advantages are high sensitivity, simple design, low weight and cost. The basic design of a gas sensorconsists of two essential parts, viz. active layer and a contact array through which the active material can be interrogated. There has been a lot of progress and work was done in the deposition of sensitive active layer by several researchers. However the design of a substrate is equally important and will continue to play an important role on the performance of the sensor .The substrate design, design of the mask, and proposed in-house work are described
Software Development for Measurement of Detonating Explosive Temperature using two Colour Pyrometry
No full textThis paper reports on the development of software for the measurement of detonating explosive temperature using two color ratio pyrometry. Planck’s law for black body radiation has been used for predicting the spectral radiance at different absolute temperatures and wavelength. Vandermonde’s algorithm is used for interpolating the emissivity values at different wavelengths. This value is further refined using least square’s approximation method. The main objective of our studies is to plot graphs for some input values of the parameters such as emissivity, spectral radiance, absolute temperature and wavelength and to establish the relation and behaviour of these parameters when value of one of them is changed. The unknown values of emissivity and radiance at known values of wavelength and temperature have been calculated by using these graphs. The software has been developed for these studies in C, C++ language and tested for two wavelengths (0.450 μm and 0.650 μm) to measure the temperature for polished tungsten
Design of a Heating Control System for Rheometer
No full textThis paper describes the heating system of rheometer and a method to ascertain the settling down of temperature of a closed volume under PID control. When the temperature stays within the desired band about the SET POINT for a predetermined time, a temperature OK signal is obtained which is used to allow further plant processes to be carried out. The developed system consists of RTD sensor, Its signal conditioning, PID controller, solid-state relay and a circuit around digital IC'