Determination of Thermal Parameters of Vanadium Oxide Uncooled Microbolometer Infrared Detector

Vanadium oxide thin films are the potential candidates for uncooled microbolometers due to their high temperature coefficient of resistance (TCR) at room temperature. A 2D array of 10-element test microbolometer without air-gap thermal isolation structure was fabricated with pulsed laser deposited vanadium oxide as IR sensing layer for the first time. Infrared responsivity of the uncooled microbolometer was evaluated in the spectral region 8-15 μm. The device exhibits responsivity of about 12 V/W at 30 Hz chopper frequency for 20 μA bias current. Thermal time constant (τ), Thermal conductance (G) and thermal capacitance (C) are the thermal parameters characterize the performance of the uncooled microbolometer infrared detectors are determined as 15 ms, ～10^-3 W/K and ～3.5 × 10^-5 J/K respectively. The influence of the thermal parameters on the performance of the microbolometer is discussed.     

Surface Tension Profiles under Various Microwave Radiation Modes

Surface tension of fluids is crucial for multiphase systems and is often controlled during industrial processes by introducing surfactants. In this study, effect of various microwave radiation modes on surface tension of water was investigated as an alternative physical method to manipulate the surface tension without using chemicals. It is found that surface tension decreased quickly while temperature increased during microwave. Once the radiation was turned off, the temperature returned rapidly as expected. However, surface tension did not recover so much. The minimum surface tension after microwave radiation depended on the power. Moreover, a second radiation can have additional reduction on surface tension.     

Clustering and selection of multiple criteria alternatives using unsupervised and supervised neural networks

There are decision-making problems that involve grouping and selecting a set of alternatives. Traditional decision-making approaches treat different sets of alternatives with the same method of analysis and selection. In this paper, we propose clustering alternatives into different sets so that different methods of analysis, selection, and implementation for each set can be applied. We consider multiple criteria decision-making alternatives where the decision-maker is faced with several conflicting and non-commensurate objectives (or criteria). For example, consider buying a set of computers for a company that vary in terms of their functions, prices, and computing powers. In this paper, we develop theories and procedures for clustering and selecting discrete multiple criteria alternatives. The sets of alternatives clustered are mutually exclusive and are based on (1) similar features among alternatives, and (2) preferential structure of the decision-maker. The decision-making process can be broken down into three steps: (1) generating alternatives; (2) grouping or clustering alternatives based on similarity of their features; and (3) choosing one or more alternatives from each cluster of alternatives. We utilize unsupervised learning clustering artificial neural networks (ANN) with variable weights for clustering of alternatives, and we use feedforward ANN for the selection of the best alternatives for each cluster of alternatives. The decision-maker is interactively involved by comparing and contrasting alternatives within each group so that the best alternative can be selected from each group. For the learning mechanism of ANN, we proposed using a generalized Euclidean distance where by changing its coefficients new formation of clusters of alternatives can be achieved. The algorithm is interactive and the results are independent of the initial set-up information. Some examples and computational results are presented.     

Federated identity management

Most confidential, valuable resources on the World Wide Web are protected by some form of authentication technology. To access these resources, either via the public Internet or private intranets, users must verify their digital identity. This can range from a simple user-name-password combination to biometric data such as fingerprints to physical objects like hardware tokens and smart cards. Federated identity management would enable individuals to interact with various service providers or Web sites with trust relationships by signing in just once.     

A liquid chromatography mass spectrometry-based method to measure organophosphorous insecticide, herbicide and non-organophosphorous pesticide in grape and apple samples

The LC-MS/MS with Quick, Easy, Cheap, Effective, Rugged and safe method was used for analysis of eighteen pesticides in fruit samples. This method was found to be accurate (≥99%), as it possessed limits of detection in the 0.002-0.087 ranges respectively. The coefficients of variations (≥0.9999) were less than 2% at the low ng g⁻¹ concentration. Mean recoveries ranged between 97 and 101%, and % RSD were below 5%. The imidacloprid mean concentrations of red grapes (125.124 ng g⁻¹) and green grapes (702.030 ng g⁻¹) differed significantly (p < 0.05) between the grapes. Similarly, the fenitrothion mean concentration of red grapes (143.66 ng g⁻¹) and green grapes (51.554 ng g⁻¹) differed significantly (p < 0.001) between the fruits. The average concentration of quinalphos was 4.317 and 1.389 ng g⁻¹ differed significantly (p < 0.01) between the grapes. In apples imidacloprid, quinalphos, triazophos, ethion and acephate were also present. This study may be helpful in developing a regional exposure database and in the facilitation of health risk assessment due to pesticide exposure.     

Green, Blue and Grey Water Footprints of Primary Crops Production in Nepal

This study aims to estimate the green, blue and grey water footprints (WFs) of nine primary crops production in 75 districts, 5 developmental regions and 3 physiographic divisions of Nepal using local meteorological, agronomical and irrigation data at high spatial resolution. The estimates are based on the framework prescribed by the guideline of the Water Footprint Network. The green and blue WFs are calculated using a water balance model whereas the grey WF is estimated as the volume of freshwater needed to dilute nitrate pollution to an acceptable level. WF varies across different crops considered, different districts, development regions and physiographic divisions. WF of potato and wheat in Nepal is comparable to the world average; but paddy, barley and pulses have higher while sugarcane and maize have lower values compared to the world average. WFs of paddy, maize, potato and wheat are lower in Terai than the Hills and Mountains due to the accessibility of irrigation system and higher crop yield. Millet, pulses, oilseeds and barley have lower WFs and are suitable for Mountains. Similarly, sugarcane is suitable for both Terai and Mountain divisions because of its lower WF. Crops in Far Western Development Region generally have higher WFs due to the low crop productivity, and higher fertilizer use.     

Thermal decomposition of Co-Al layered double hydroxide: Identification of precursor to oxide with spinel structure

The layered double hydroxide (LDH) of Co with Al decomposes to yield an oxide residue with the spinel structure below 250°C. The decomposition reaction is preceded by the formation of an intermediate hydroxide in which the metal hydroxide layers are regularly stacked about the c-crystallographic axis, but the layers themselves are aperiodic. Aperiodicity is modeled by locating randomly chosen Co²⁺ ions in tetrahedral sites in the interlayer region. This phase is characterized by a single strong basal reflection in its powder diffraction pattern. All other reflections are extinguished on account of (i) turbostratic disorder which destroys all hkl reflections and (ii) layer aperiodicity, which destroys all two dimensional hk reflections. Given its topochemical relationship with the spinel structure, such an intermediate is a necessary precursor to spinel formation.     

Electrochemical synthesis of perovskite oxides

Hydroxide precursors to perovskite oxides of the formula, LnMO₃ (Ln = La, Pr, Nd; M = Al, Mn, Fe) and LaMO₃ (M = Co and Ni) were synthesized by electrogeneration of base by cathodic reduction of the appropriate mixed-metal nitrate solution. The precursors were heat treated at different temperatures to obtain the perovskite oxides. The bath composition for various systems was optimized to get a single-phase oxide product. This method can be adapted as a simple route to the synthesis of perovskite oxide coatings on conducting substrates.