An Energy Efficient Clustered Gravitational and Fuzzy Based Routing Algorithm in WSNs

Wireless Personal Communications - Wireless sensor networks consist of many tiny sensor nodes which are deployed in various geographical locations for sensing the normal spectacles and also to...     

Compact Meandered Folded-Dipole RFID Tag Antenna for Dual Band Operation in UHF Range

Wireless Personal Communications - A meandered tag antenna is proposed for dual band operation in UHF (Ultra High Frequency) range at f1?=?866 MHz and...     

Internet of Things (IoT), Applications and Challenges: A Comprehensive Review

Wireless Personal Communications - During recent years, one of the most familiar names scaling new heights and creating a benchmark in the world is the Internet of Things (IoT). It is indeed the...     

A new single-component low-cost emitter etch-back process for silicon wafer solar cells

A way of achieving lightly doped emitter is a combination of a heavy emitter diffusion and emitter etch back, which has an added advantage of phosphorous diffusion gettering. However, this chemical emitter etch-back process must fulfil some critical requirements, e.g. cost-effectiveness, near-conformal Si etching even after deep emitter etch back, controlled Si etch rate, post-etch clean Si surface and lowest safety issues in chemical handling and drainage. In this work, we report a new low-cost (less than 1 US Cents/wafer), single-chemical, non-acidic, high-throughput emitter etch-back process for tube-diffused emitters for crystalline Si wafers. This process uses only sodium hypochlorite solution at 80 °C as the Si etchant. This process is versatile with its applications on phosphorous and boron tube-diffused monocrystalline Si and phosphorous tube-diffused multicrystalline Si wafers. The preparation, usage and drainage of this highly diluted solution are easy and safe. The Si etching process leads to excellent spatial uniformity over large-area Si wafers (243 cm²). With deep etch back resulting in a change of sheet resistance by ~60 Ω/sq, the standard deviation value changes by only 2.7%. High surface conformity in the etch-back surface is evident from reflectance studies. Quasi-steady-state photoconductance and photoluminescence imaging are used to demonstrate improved electrical parameters of the etch-back wafers.     

PolyCodes: generating cancelable biometric features using polynomial transformation

Multimedia Tools and Applications - Cancelable biometrics is a template protection technique proposed to bridge the growing gap between ‘biometrics for security’ and ‘security for...     

Multi-Resonating Structures for Broadband Impedance Matching in Ultrawideband Antenna

Wireless Personal Communications - The feature of Dynamic topology configuration of MANET reciprocates the security constraints and bring in many security threats that hamper the routing and time...     

Cancelable features using log-Gabor filters for biometric authentication

Wide spread use of biometric based authentication requires security of biometric data against identity thefts. Cancelable biometrics is a recent approach to address the concerns regarding privacy of biometric data, public confidence, and acceptance of biometric systems. This work proposes a template protection approach which generates revocable binary features from phase and magnitude patterns of log-Gabor filters. Multi-level transformations are applied at signal and feature level to distort the biometric data using user specific tokenized variables which are observed to provide better performance and security against information leakage under correlation attacks. A thorough analysis is performed to study the performance, non-invertibility, and changeability of the proposed approach under stolen token scenario on multiple biometric modalities. It is revealed that generated templates are non-invertible, easy to revoke, and also deliver good performance.     

Mathematical analysis of transport properties of polymer films for food packaging. II. Generalized water vapor models

Deterioration or spoilage of dehydrated food products stored in flexible packaging materials depends on the partial pressure of water vapor in the environment of the stored food. Mathematical analysis of the diffusion of water vapor through semipermeable polymer films using Nernst-Planck equations is combined with non-liner water sorption isotherms on food to establish criteria and optimum conditions for storage stability of dehydrated food. Langmuir, Brunauer-Emmet-Teller (BET), Halsey, Oswin and Freundlich isotherms are used for various ranges of water activity. It is shown that a single parameter, the permeability-sorption constant, based on the physical properties of the polymer and the sorptive properties of the food, accounts for both diffusion and adostption and can be used to accurately determine maximum storage times and can be used to accurately determine maximum storage times and to optimize the selection of packaging films. The theory is extended to thermodynamically compatible solute-polymer systems, where the polymer film is swollen appreciably by the diffusing species.     

Dynamic mechanical analysis of fibers. I. Effect of experimental variables and material type

Depending upon the fiber material, some of the experimental variables can have a profound effect on the dynamic tensile modulus vs. temperature data. With the use of an experimental fiber (25°C < T_g < 75°C; T_m > 220°C; hot stretched), the effect of several variables, e.g., moisture/volatiles, annealing/relaxation, frequency (strain rate), pretension, and % strain on the modulus retention term [(E_100°C/E_25°C) × 100] have been studied. Of these variables, pretension and especially % strain dramatically increase the modulus retention and this effect is attributed to the elastic orientation under force (EOF), i.e., it exists only in the presence of tensile forces and is reversible. Such an effect was insignificant for Kevlar (T_g ? 375°C) and absent for steel wire. Dynamic modulus measurements at 25°C using sonic techniques also support the EOF phenomenon in polyethylene yarns (T_g ～ ?30°C) but not in Kevlar polymide yarns (T_g ～ 375°C).     

Dynamic mechanical analysis of fibers. II. Estimation of fiber orientation and characterization of heat set PET yarns

A drawn PET yarn was heat set (annealed) at temperatures between 110°C and 245°C in an unconstrained mode and the samples characterized by dynamic mechanical analysis (DMA). A method for estimating the fiber orientation factor (α) is proposed using DMA and shown to be more sensitive than the crystalline orientation (x-ray diffraction) or total orientation (birefringence) measurements of the heat set yarns. The extension/shrinkage behavior of the heat set yarns has been discussed in the light of morphological changes, e.g., degree of orientation and the micro-crystallite formation. Unlike in the unconstrained mode, heat setting under constraint does not lead to the formation of micro-crystallites as revealed by differential scanning calorimetry. As a consequence, although the modulus and degree of orientation increase upon constrained annealing, the thermal stability, i.e., loss of orientation (reflected by shrinkage) could not be improved.