Development of a Highly Selective,Sensitive, and Fast Response Upconversion Luminescent Platform for Hydrogen Sulfide Detection

Hydrogen sulfide (H₂S) has been recognized as one of most important gaseous signaling molecules mediated by a variety of physiological and pathological processes. Yet, its functions remain largely elusive due to the lack of potent monitoring methods. Hereby this issue is addressed with a powerful new platform—dye‐assembled upconversion nanoparticles (UCNPs). A series of chromophores with different absorption bands and fast responses towards H₂S is combined with UCNPs and results in a library of H₂S sensors with responsive emission signals ranging from the visible to the near‐infrared (NIR) region. These nanoprobes demonstrate highly selective and rapid responses to H₂S in vitro and in cells. Furthermore, H₂S levels in blood can be detected using the developed nanoprobes. Hence the reported H₂S sensing platform can serve as a powerful diagnostic tool to research H₂S functions and to investigate H₂S‐related diseases.     

Microstructural investigation on mechanical behavior of soil-geosynthetic interface in direct shear test

Interface shear strength between soil and geosynthetics mainly depends on the mechanical and physical properties of soil, geosynthetics and the normal stress acting at the interface. This paper presents results of an extensive experimental investigation carried out on sand-geosynthetic interface using modified large direct shear box. The study focusses on the shearing mechanism at the sand-geosynthetic interface and the effect of different parameters on the shearing mechanism. Smooth HDPE geomembrane, nonwoven needle punched geotextile and two types of sand having different mean particle size, have been used in the present study. Microstructural investigation of deformed specimen through Field Emission Scanning Electron Microscope (FESEM) reveals the shearing mechanism which includes interlocking and fiber stretching for sand-geotextile while sliding, indentation and plowing for sand-geomembrane interface. The shearing mechanism for sand-geomembrane interface highly depends on the normal stress and degree of saturation of sand. The critical normal stress that demarcates the sliding and plowing mechanism for sand-geomembrane interface is different for dry and wet sand. The amount of scouring (or plowing) of the geomembrane surface reduces with increase in the mean particle size of sand. FESEM images revealed that the sand particles get adhered to the geotextile fibers for tests involving wet sands. The present microstructural study aided in understanding the shearing mechanism at sand-geosynthetic interface to a large extent.     

Analysis of the “Wavelet Tree Quantization” watermarking strategy and a modified robust scheme

Here we study a recently proposed watermarking scheme based on the paper “Wavelet Tree Quantization” (WTQ) by Wang and Lin (IEEE Trans Image Process 13(2):154–165, 2004). In given scheme, wavelet coefficients corresponding to the same spatial locations are grouped together. Two such groups, selected at random, constitute a supertree. Some of these supertrees are quantized to embed the watermark information in the image. In the process of cryptanalysis we first identify the groups which are quantized during the watermark insertion process. Then we select the non-quantized groups and quantize them too, to remove the watermark. Experimental results show that the watermark is completely removed by this attack. The cryptanalysis falls under the cipher text only jamming attack which requires only a single watermarked copy. Further, we suitably modify the WTQ scheme to make it robust against such cryptanalytic attacks.This is an extended and revised version of the paper Cryptanalysis of “Wavelet Tree Quantization” Watermarking Scheme presented at the International Workshop on Distributed Computing, IWDC 2004, Kolkata, 27–30 December 2004, Lecture Notes in Computer Science, vol. 3326, pp. 219–230. Springer, Berlin Heidelberg New York (2004). Section 4 of this paper introduces a modified scheme which is an addition over the conference version. Part of this work has been done while the author T. K. Das was visiting Indian Statistical Institute, Kolkata during 2004.     

Artificial neural networks and genetic algorithm for bearing fault detection

A study is presented to compare the performance of three types of artificial neural network (ANN), namely, multi layer perceptron (MLP), radial basis function (RBF) network and probabilistic neural network (PNN), for bearing fault detection. Features are extracted from time domain vibration signals, without and with preprocessing, of a rotating machine with normal and defective bearings. The extracted features are used as inputs to all three ANN classifiers: MLP, RBF and PNN for two- class (normal or fault) recognition. Genetic algorithms (GAs) have been used to select the characteristic parameters of the classifiers and the input features. For each trial, the ANNs are trained with a subset of the experimental data for known machine conditions. The ANNs are tested using the remaining set of data. The procedure is illustrated using the experimental vibration data of a rotating machine. The roles of different vibration signals and preprocessing techniques are investigated. The results show the effectiveness of the features and the classifiers in detection of machine condition.     

Relationship between Growth, Structure and Superconductivity of Single Crystal YBa2Cu3O7-δ

We study the crystal growth of YBa ₂ Cu ₃ O _7- with additives, using ac susceptibility, X-ray diffraction and STM. One specific additive, BaF ₂ , dramatically improves both the crystal growth and the superconducting properties. A cluster growth model is proposed to describe the function of the additive. F _– reduces the Al contamination of Cu-O chains, and the orthorhombicity increases. On a nanometer scale, the roughness of the chains decreases markedly. Superconductivity is further enhanced using non-contaminating crucibles. Large single crystals with T _C = 93.7 K and T _C = 0.1K were grown in Y ₂ O ₃ or BaZrO ₃ crucibles using the BaF ₂ additive.     

Inventory model with two rates of production for deteriorating items with permissible delay in payments

Some decentralized smoothing problems are solved by applying a forward-pass fixed-interval smoother formula in discrete-time systems. It is assumed that a simple estimation structure consists of a global processor and of two local processors. Two cases are considered for the problems of decentralized smoothing and smoothing update: when the local backward-pass information filtered estimates are available, and when the local-smoothed estimates are available. Some features of present algorithms are discussed from the point of view of data transmissions and numerical computations, etc.     

Efficient processing of oil–water emulsions confined within 2D cylinders with various microwave irradiations: Role of metallic annulus

Extensive studies have been carried out to investigate the role of metallic annulus on efficient microwave processing of oil–water emulsions confined within 2D cylinders in the presence of lateral/radial irradiations. A preliminary study has been carried out via average power within a sample vs. sample diameter to estimate microwave power absorptions for various o/w and w/o emulsions with specific fractions of the dispersed phase (?) in the absence of metallic annulus. Based on those studies, various regimes (sample dimension) have been identified for each emulsion (o/w or w/o) based on appropriate length scales. Two types of metallic annular configurations have been considered such as circular and square annuli for further analysis via average power vs. aspect ratio (a) distribution for each regime. Based on that study, suitable aspect ratios have been chosen to carry out detailed analysis on spatial power and temperature distributions for each regime with metallic annuli. Finally, optimal heating strategies have been recommended based on two significant factors such as ‘large heating rate’ with ‘minimal thermal runaway’ for various regimes of o/w and w/o emulsions. It is observed that average power absorptions show greater intensification due to metallic annulus for most of the regimes of o/w emulsions than that for corresponding regimes of w/o emulsions due to lateral and/or radial irradiations. However, in general, for regimes with smaller diameters (for both o/w and w/o samples) radial irradiation is favored, whereas for large regimes, lateral irradiation is favored as the optimal heating strategies.     

Generalised fuzzy soft sets

In this paper, we define generalised fuzzy soft sets and study some of their properties. Application of generalised fuzzy soft sets in decision making problem and medical diagnosis problem has been shown.