An iterative approach to design a SAW filter having desired response

Present work proposes an iterative technique to estimate reflection weighting function and transduction weighting function simultaneously to achieve a desired single-phase unidirectional transducer (SPUDT) response. The technique uses the p-matrix formulation in order to describe characteristics of a SPUDT. Simulation results are presented to show the validity of the approach.     

Fatty acid composition and organoleptic quality of four clones of durian (Durio zibethinus,murr.)

This study was undertaken to determine and relate the lipid content and fatty acid composition of four different durian (Durio zibethinus, Murr.) clones, i.e., D₂₄, D₂, D₆₆ and D₈, with their respective organoleptic scores. Both lipid content and the fatty acid composition were found to vary among these clones. Clones D₂₄ and D₂, which contained a higher proportion of lipids but lower unsaturated fatty acid contents, received high organoleptic scores when compared to clones D₆₆ and D₈. It was found that the lower the palmitic: palmitoleic acid ratio in the lipid of a durian clone, the higher its organoleptic quality.     

Bulk heterojunction formation with induced concentration gradient from a bilayer structure of P3HT:CdSe/ZnS quantum dots using inter-diffusion process for developing high efficiency solar cell

Bulk heterojunction (BHJ) solar cells consisting of poly(3-hexylthiophene) (P3HT) as donor and cadmium selenide/zinc sulphide (CdSe/ZnS) core shell quantum dots (QDs) as acceptor have been developed. Starting from the bilayer of P3HT/QD structure a BHJ is induced using the process of thermal inter-diffusion. The absorption measurements on the bilayer structure show that the absorption coefficient increases and the absorption spectrum becomes broader in the annealed device. Also, the photoluminescence of the annealed device is found to decrease by an order of magnitude showing a significant transfer of electrons to the QDs. With this approach and under broadband white light with an irradiance of 8.19 mW/cm², we have been able to achieve a power conversion efficiency of 5.1% and fill factor 0.45 for this solar cell.     

Application of Hyperspectral Technique for Color Classification Avocados Subjected to Different Treatments

In this study, the applicability of hyperspectral technique, a fast and non-destructive, novel method was investigated for the color discrimination of avocados subjected to different treatments. Fruits like avocados are coated with edible films to extend their shelf life. Using different formulations of coating with varying pectin, beeswax, and sorbitol contents, nine different coating preparations with potential to influence the ripening behavior of avocados were developed. Avocados were coated with these formulations, air-dried, and stored at room temperature. Concurrently, the reflectance responses of the avocado fruits were measured in 2,151 wavebands (350 to 2500 nm) with a field spectroradiometer. To tackle the co-linearity that exists between the spectral observations, aggregated 10- and 20-nm data sets were used. Using a stepwise procedure, the most effective wavebands capable of discriminating treatment effects were selected. By applying a discrimination procedure with a well-chosen subset of the selected wavebands, treatments were correctly classified with more than 92% accuracy.     

Polarization Independent Dual-band Metamaterial Based Radar Absorbing Structure (RAS) for MillimeterWave Applications

The EM analysis of multi-layered metamaterial based radar absorbing structure (RAS) with dual-band characteristics in millimeter wave frequency regime has been carried out in this paper using transmission line transfer matrix (TLTM) method for TE and TM polarizations. The proposed metamaterial-based RAS exhibits dual-band characteristics at centre frequencies 120 GHz and 175 GHz with very low power reflection. It absorbs more than 90% power of incidence wave over the frequency range from 111-131 GHz at first resonance and from 164.5-185 GHz at second resonance without metal backing plate, which is desirable for stealth applications. It also showed very low (< 1.6%) transmission over the frequency of interest for both TE and TM polarizations. The proposed metamaterial-RAS has potential applications in the design of multi-band sensor systems and RCS reduction in millimeter wave frequency regime.     

Electromagnetic Performance Analysis of Novel Multi-band Metamaterial FSS for Millimeter Wave Radome Applications

The electromagnetic design and performance analysis of dual/ multi-band metamaterial frequency selective surface (FSS) structures have been carried out for radome applications in microwave and millimeter wave frequency regimes. The proposed metamaterial FSS structure, consisting of cascaded MNG (mu-nega -tive) and DPS (double positive) layers, exhibits dual-band transmission responses at V-band and W-band. Excellent transmission efficiency (more than 95%) has been obtained over the frequency range 45.8-53.1 GHz at first resonance, and from 93.0-97.1 GHz at second resonance. The incorporation of additional DPS layer to the proposed metamaterial-FSS structure facilitates multiband bandpass characteristics at 30 GHz (in Ka-band), 64 GHz (in V-band), and 93.6 GHz (in W-band). The reflection and insertion phase delay characteristics are also analyzed at high incidence angles in view of streamlined airborne nosecone radome applications.     

Thermal modelling of a few novel solar collector-cum-storage units for passive heating

Analytical models have been put forward to predict the thermal performance of passive heating systems, which have previously been suggested. The systems consist of a water vessel for heat storage and a structure positioned on its outside wall, which act as a solar collector and a thermal insulation for the storage, respectively. Four different variations of structures have been considered and numerical calculations performed corresponding to the physical parameters of an earlier reported experimental study. The analysis is able to predict the experimental results fairly satisfactorily.     

Modeling of turning process cutting forces for grooved tools

A mechanistic modeling approach to predicting cutting forces for grooved tools in turning has been developed. The model assumes the existence of an equivalent orthogonal cutting operation for any oblique operation. The effects of tool nose radius and chip flow have been incorporated by defining a set of equivalent groove parameters. Two calibration methods have been presented for the model. A variety of commercial grooved inserts were chosen to validate the model. The workpiece material used was AISI 1018 steel. The force predictions from the model were found in good agreement with the measured forces. The effects of cutting conditions and groove parameters on the cutting forces and their implication in designing grooved tools were also determined.     

A multicriteria intuitionistic fuzzy group decision making for plant location selection with ELECTRE method

Plant location selection, the process of finding a suitable location for plant of a project has a strong influence on the success of industrial venture with the goal to minimize cost and maximize the use of resources. Thus, plant location selection problem is a multicriteria decision-making problem involving several conflicting criteria on which decision makers' knowledge is vague and imprecise. Therefore, in this study, the elimination and choice translating reality (ELECTRE) method is proposed with intuitionistic fuzzy sets for selection of appropriate plant location in group decision-making environment to tackle uncertainty of the information provided by decision makers and a plant location selection problem is considered to illustrate the proposed intuitionistic fuzzy-ELECTRE method. The ratings of alternatives with respect to each criterion and the weights of each criterion are taken as linguistic terms further characterized by triangular intuitionistic fuzzy sets.