Energy conservation in wireless sensor networks: a rule-based approach

The research reported in this paper addresses the problem of energy conservation in wireless sensor networks (WSNs). It proposes concepts and techniques to extract environmental information that are useful for controlling sensor operations, in order to enable sensor nodes to conserve their energy, and consequently prolong the network lifetime. These concepts and techniques are consolidated in a generic framework we term CASE: Context Awareness in Sensing Environments framework. CASE targets energy conservation at the network level. A subset framework of CASE, we term CASE Compact, targets energy conservation at the sensor node level. In this paper, we elaborate on these two frameworks, elucidate the requirements for them to operate together within a WSN and evaluate the applications they can be applied to for energy conservation.     

The Geometric Phase

Abstract

The change in the phase of a beam of light produced by a cyclic change in its state of polarization is an example of the geometric phase that can be verified by interferometric measurements. This paper presents a quantum-field theoretical analysis of the geometric phase interferometer in the limit of a small photon number, as well as some experimental results that confirm that the optical effects due to the geometric phase persist down to the single-photon level.     

White-light Phase-stepping Interferometry for Surface Profiling

Abstract

Interferometric profilers suffer from phase ambiguities if the measurement range involves a change in the optical path difference greater than a wavelength. This limitation has been overcome by using white light and scanning the object in height. We show how an achromatic phase shifter operating on the geometric phase can be used to evaluate the fringe contrast directly and to locate the position of the zero-order white-light fringe along the scanning axis.     

Modelling,design and optimization of compact taper and gratings for mode coupling to SOI waveguides at C-band

In this work, the design and optimization of compact taper is presented to enable coupling of infrared light in the C-band with the nano-photonic silicon-on-insulator (SOI) integrated optical waveguide. The proposed compact taper results in ～96% transmission efficiency for the taper length of ～5?µm and ～99.5% transmission efficiency for the taper length of 10?µm. The use of the proposed compact taper significantly reduces the foot print of optical coupler (grating and proposed compact taper) to (10?×?5)?µm² with ～96% transmittance and (10?×?10)?µm² with ～99.5% transmittance. The end-to-end coupling loss is less than 0.01?dB in the C-band. The compact taper along with grating presented in this work can be used as an efficient optical coupler for mode coupling from fibre to SOI single-mode optical waveguide in high density optical integrated circuits operating at 1550?nm.     

Experimental Investigation To Study the Influence of Handle Diameter on Low‐Frequency,Hand–Arm Vertical Vibration

Handle vibration from equipment or machines influences musculoskeletal activity as well as comfort in handling the same. New technology can be worse than no technology if it was not developed correctly as ergonomic research has clearly demonstrated the relationship between injury risk and poorly designed hand tools. Clinical and epidemiological studies have shown that operators of handheld power tools are prone to develop various vibration‐induced disorders of the hand and arm, which are collectively referred to as “hand–arm vibration syndrome.'' The vibration direction has a great influence on the transmitted vibration. The present study focuses the effects of low‐frequency vertical vibration on hand to shoulder from handles of different size. The electrodynamic exciter is used for simulating vibration to a vertical handles of four different diameters. PULSE LabShop software is used for evaluating the magnitude of vibration in different frequency bands. The vibration characteristic data were acquired in the y_h axis at the wrist, elbow, and shoulder for bent arm and extended arm postures with vibration excitation of 4.5 m/s². Transmissibility characteristics are computed to determine the influence of handle diameter in y_h vibration transmitted to the hand–arm system. The magnitude of vibration transmitted within the hand, elbow, and shoulder was observed to be dependent on the handle size; larger handles cause higher vibration transmissibility. The results also show that the human hand–arm system in an extended arm posture amplifies the vibration transmitted than bent arm in a small difference. © 2011 Wiley Periodicals, Inc.     

Development of SQUID-Based System for Nondestructive Evaluation

This article describes the development of a superconducting quantum interference device (SQUID)-based system for nondestructive evaluation. The setup incorporates an in-house developed thin-film-based Nb SQUID with readout flux locked loop electronics and consists of a liquid helium cryostat with adjustable stand-off distance, a precision XY- thetas scanner for studying both flat and cylindrical samples, and a data acquisition system. The system has been used for the detection of artificially engineered subsurface defects in aluminum plates and to track magnetic-to-nonmagnetic phase transformation in stainless steel [grade 316L(N)] weldment specimens subjected to low cycle fatigue deformation.     

Nutritional and toxicological evaluation of wheat grown on soils with or without fly ash treatment

BACKGROUND: Fly ash disposal has recently posed a huge environmental problem due to storage, apart from apprehension about possible contamination of soil, crop produce and ground water with toxic trace and heavy metal and radio nuclides. The purpose of the present study was to evaluate nutritional and toxicological aspects of wheat grown on soils treated with fly ash. Wheat was grown on soils with fly ash (200 t ha^?1) and without fly ash at two different geographical locations in India. One kilogram each of 36 samples randomly collected from three replicates of wheat grown with and without fly ash were subjected to various analytical techniques to determine the nutrient composition, mineral, trace element and heavy metal content. Furthermore, wheat grown on soils treated with fly ash was also incorporated into the diet at 90% level, fed as a feed for 26 weeks to Wistar/NIN rats for protein and toxicological evaluation. RESULTS: Moisture, protein and ash content of wheat samples showed no difference between fly ash treated and controls. Similar observations were also seen with trace and heavy elements. CONCLUSION: Results indicated there is no difference between wheat samples grown in soils with fly ash and without fly ash. Studies also clearly indicated that there are no adverse effects on haematological, biochemical or histopathological parameters when wheat was fed to rats for 6 months. This indicates that wheat grown on fly ash treated soils may be safe for human consumption. Copyright © 2008 Society of Chemical Industry     

Simple dipstick cryostat with versatile temperature controller for high thermal stability

A simple dipstick type vapour cryostat and a versatile electronic temperature controller which uses a proportional, integral and differential type of control are described. They have been used together for the calibration of thermometers in the liquid helium temperature range and for the measurement of the transition temperature of superconductors. Temperature stability of 2 mK (typical) is achieved easily at a working temperature of 7 K for a period exceeding an hour. The use of the system is quite general and can readily cover the temperature range up to 300 K with a suitable choice of temperature sensor and heat input.