162 research outputs found

    Experiments in Scattered Light. Angles of First Minimum

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    Studies on Electrolytic preparation of Iron Copper Powders

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    Factors affecting the physical characteristics and chemical composition of iron-cooper powder deposits obtained by electrolysis, have been investigated. Effect of process variables such as current density, pH, temperature, time, concentration of electrolyte and agitation, has been studied over a wide range, for theoretical interest and to obtain powder deposits of a definite composition. Metallographic examination of iron-copper powder thus prepared after compacting and sintering, has revealed uniform and homogeneous dispersion of the two metals. The technique of preparation presented in this paper is a better substitute to the conventional practice of preparing binary metal powders by mixing and tumbling

    High temperature regenerative H.sub.2 S sorbents

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    Efficient, regenerable sorbents for removal of H.sub.2 S from high temperature gas streams comprise porous, high surface area particles. A first class of sorbents comprise a thin film of binary oxides that form a eutectic at the temperature of the gas stream coated onto a porous, high surface area refractory support. The binary oxides are a mixture of a Group VB or VIB metal oxide with a Group IB, IIB or VIII metal oxide such as a film of V-Zn-O, V-Cu-O, Cu-Mo-O, Zn-Mo-O or Fe-Mo-O coated on an alumina support. A second class of sorbents consist of particles of unsupported mixed oxides in the form of highly dispersed solid solutions of solid compounds characterized by small crystallite size, high porosity and relatively high surface area. The mixed oxide sorbents contain one Group IB, IIB or VIIB metal oxide such as copper, zinc or manganese and one or more oxides of Groups IIIA, VIB or VII such as aluminum, iron or molybdenum. The presence of iron or aluminum maintains the Group IB, IIB or VIIB metal in its oxidized state. Presence of molybdenum results in eutectic formation at sulfidation temperature and improves the efficiency of the sorbent

    Performance Driven Reliable Link Design for Networks on Chips

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    With decreasing feature size of transistors, the interconnect wire delay is becoming a major bottleneck in current Systems on Chips (SoCs). Another effect of shrinking feature size is that the wires are becoming unrealable as they are increasingly susceptible to various noise sources such as cross-talk, coupling noise, soft errors etc. Increasing importance of wire delay an reliability has lead to a communication centric design approach, Networks in Chip (NoC), for building complex SoCs. Current NoC communication design methodologies are based on conservative design approaches and consider worst case operating conditions for link design, resulting in lare latency penalty for data transmission. In order to substantially descrease the link delay and therby increase system performance an aggressive design approach is needed. In this work we present Terror, timing error tolerant communication system, for aggressively design the links of NoCs. In our methodology, instead of avoiding timing errors by worst-case design, we do aggressive design by tolerating timing errors. Simulation results show large latency savings (up to 35%) for the Terror based system compared to traditional design methodology

    A novel semi-fragile forensic watermarking scheme for remote sensing images

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    Peer-reviewedA semi-fragile watermarking scheme for multiple band images is presented. We propose to embed a mark into remote sensing images applying a tree structured vector quantization approach to the pixel signatures, instead of processing each band separately. The signature of themmultispectral or hyperspectral image is used to embed the mark in it order to detect any significant modification of the original image. The image is segmented into threedimensional blocks and a tree structured vector quantizer is built for each block. These trees are manipulated using an iterative algorithm until the resulting block satisfies a required criterion which establishes the embedded mark. The method is shown to be able to preserve the mark under lossy compression (above a given threshold) but, at the same time, it detects possibly forged blocks and their position in the whole image.Se presenta un esquema de marcas de agua semi-frágiles para múltiples imágenes de banda. Proponemos incorporar una marca en imágenes de detección remota, aplicando un enfoque de cuantización del vector de árbol estructurado con las definiciones de píxel, en lugar de procesar cada banda por separado. La firma de la imagen hiperespectral se utiliza para insertar la marca en el mismo orden para detectar cualquier modificación significativa de la imagen original. La imagen es segmentada en bloques tridimensionales y un cuantificador de vector de estructura de árbol se construye para cada bloque. Estos árboles son manipulados utilizando un algoritmo iteractivo hasta que el bloque resultante satisface un criterio necesario que establece la marca incrustada. El método se muestra para poder preservar la marca bajo compresión con pérdida (por encima de un umbral establecido) pero, al mismo tiempo, detecta posiblemente bloques forjados y su posición en la imagen entera.Es presenta un esquema de marques d'aigua semi-fràgils per a múltiples imatges de banda. Proposem incorporar una marca en imatges de detecció remota, aplicant un enfocament de quantització del vector d'arbre estructurat amb les definicions de píxel, en lloc de processar cada banda per separat. La signatura de la imatge hiperespectral s'utilitza per inserir la marca en el mateix ordre per detectar qualsevol modificació significativa de la imatge original. La imatge és segmentada en blocs tridimensionals i un quantificador de vector d'estructura d'arbre es construeix per a cada bloc. Aquests arbres són manipulats utilitzant un algoritme iteractiu fins que el bloc resultant satisfà un criteri necessari que estableix la marca incrustada. El mètode es mostra per poder preservar la marca sota compressió amb pèrdua (per sobre d'un llindar establert) però, al mateix temps, detecta possiblement blocs forjats i la seva posició en la imatge sencera

    Effect of third component on separation behavior of water+t-butanol+Na2SO3/Na2SO4 system at 298±2 K

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    The liquid-liquid and liquid-liquid-solid equilibria for the ternary t-butanol-water-Na2SO3/Na2SO4 system is reported at ambient pressure and at 298±2 K. The solubility data of solutions of Na2SO3/Na2SO4 in water, t-butanol and solutions of varying compositions of t-butanol in water are reported. The phase diagrams for the studied systems are developed and salting-out effect of salt anion has been described. The structural properties of aqueous t-butanol solutions and the salting-out effect of SO32- and SO42- ions to cause phase separation have been explained. The salting-out ability of Na2SO3 is higher than that of Na2SO4 since the Gibbs free energy of hydration (ΔGhyd) of SO42- (−1080 kJ mol-1) is lower than that of SO32- (−1295 kJ mol-1) ion

    Mitrofanoff urinary diversion in a patient with cerebral palsy

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    Cerebral palsy is the most common motor disability in childhood which result in huge socioeconomic costs. This children have a significant incidence of lower urinary tract symptoms. Clean intermittent self-catheterization is needed to avoid deterioration of renal function. But significant spasticity and resulting contractures of the adductors can interfere with the caretakers’ ability to provide perineal hygiene. Surgery in cerebral palsy affected child is challenging due to multiple associated comorbidities. The aim of this report is to describe quality of life and renal function for a mentally retarded child with cerebral palsy before and after Mitrofanoff diversion without bladder augmentation
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