On-line partial discharge detection in cables

This paper describes an on-line PD (partial discharge) detection technique applicable to power cables. The method can be applied to both wire screen and solid shielded cables. In wire screen shielded cables, PD components with frequencies <100 MHz can be detected at distances over 150 m from the source, PD activity with levels as low as 20 pC can be detected within 100 m. However, in the case of solid shielded cables, PD levels of ⩾50 pC can be measured within 60 m in the frequency range <50 MHz. This method also can be utilized to check cable accessories such as splices and terminations. PD pulses with frequencies to ~300 MHz can be measured near the joints and terminations. The suitability and the sensitivity of the VHF technique were checked against two other alternative PD detecting techniques (pulse phase analyzer and high speed digital oscilloscope) by performing PD measurements in standard air gap and defects induced in EPR-insulated cable under laboratory-controlled conditions. The suitability and sensitivity of the VHF method were as good as the two alternative PD detection techniques     

Synthesis and characterization of novel 2,5-diphenyl-1,3,4-oxadiazole derivatives of anthracene and its application as electron transporting blue emitters in OLEDs

With a general aim to make anthracene derivatives multifunctional (n-type emitter) and also study their suitability as electron transport layers for organic light emitting diodes (OLED), we report the synthesis and characterization of five novel molecules in which the 9 and 10 positions of anthracene have been directly substituted by 2,5-diphenyl-1,3,4-oxadiazole groups. We have carried out detailed characterization of these molecules which include photophysical, electrochemical, thermal, electroluminescent and computational studies. The electron affinity is very high, around 3.7 eV, and the ionization potential is around 6.7–6.8 eV, which is relatively higher than the most commonly used electron transport electroluminescent layer Alq₃. The studies reveal that the new molecules being reported by us, in addition to the high thermal stability, are quite efficient in a two layer unoptimized nondoped device with the device structure ITO/α-NPD/10a–11b/LiF/Al and have an emission in pure blue. They also show very high efficiency as electron transport layer in device structure ITO(120 nm)/α-NPD(30 nm)/Ir(ppy)₃ doped CBP(35 nm)/BCP(6 nm)/10a(28 nm)/LiF(1 nm)/Al(150 nm). From these studies we conclude that these anthracene derivatives also have considerable potential as multifunctional layers and as electron transport layers in OLED.     

On Prediction of Amorphous Phase Forming Compositions in the Iron-Rich Fe-Zr-B Ternary System and Their Synthesis

A thermodynamic model parameter P _H-S , which is a product of enthalpy of chemical mixing and mismatch entropy normalized by Boltzmann’s constant, was used as a guiding tool to predict amorphous phase forming compositions in Fe-rich alloys of the Fe-Zr-B system. Attempts were made to evaluate the effect of Zr addition on the P _H-S parameter and phase formation by mechanical alloying (MA) and rapid solidification processing (RSP). A systematic evaluation of the P _H-S parameter of various binary compounds in the Fe-Zr-B system and ternary alloys indicated ~–7 kJ/mol as a lower bound for the formation of amorphous phase. Model predictions were verified with phase formation in two random compositions in the Fe-rich end of the Fe-Zr-B system synthesized by MA and RSP.     

Development of Ni–Cu Materials Library by Using Combinatorial Pulsed Electrodeposition

Combinatorial materials fabrication and high-throughput characterization methods offer a new experimental paradigm to accelerate the enhancement of known and the discovery of new materials in materials science and engineering. In this study, the composition spread library of binary Ni–Cu alloy system is synthesized combinatorially onto a copper substrate using pulsed electrodeposition (PED) from a single sulfate bath with a complexing agent trisodium citrate in a modified Hull cell. Different current densities are expected on the tilted cathode which varied the composition along lateral direction and generated Ni–Cu binary spread. Crystallographic structure as well as atomic concentration of the constituent elements of the deposited binary Ni–Cu alloy film along the lateral direction is determined as a function of fabrication parameters. The presented results indicate the successful development of Ni–Cu binary spread (10–90 at.%) via PED.     

Development of upgradation schemes for gravity load designed beam–column sub-assemblage under cyclic loading

In this paper, it is attempted to upgrade the poor gravity load designed (‘GLD’) exterior beam–column sub-assemblage for improving the seismic performance. Three different upgradation schemes have been proposed for ‘GLD’ sub-assemblage under seismic loading. In all three schemes, shear upgradation was carried out by using GFRP wrapping, and joint region was upgraded by using steel plate jacketing with through–through steel bolts. For flexural upgradation, CFRP fiber and laminates were respectively used in first two schemes. Third upgradation scheme was similar to that proposed in the first scheme but limited to the D-region (disturbed region) only. Before implementing the upgradation schemes, proper surface treatment on original specimens were carried out. First, the original ‘GLD’ and target ‘ductile’ sub-assemblages were experimentally investigated under reserve cyclic loading. Thereafter, the upgraded sub-assemblages were investigated under same cyclic load history as that was opted for ‘GLD’ one. Specimen details considered, materials used, execution procedure for upgradation adopted and experimental investigation carried out are discussed in step by step. It was observed from the investigation that the ‘GLD’ specimen seized to function under reserve loading and the lack in proper anchorage of beam bottom reinforcement formed a huge crack at the joint face. Under reverse cyclic loading, it was found that the upgraded specimens showed a considerable improvement in seismic performance. Further, the CFRP laminate based upgraded specimen showed better performance over the CFRP fiber based one and the plastic hinge could be successfully shifted from the joint zone to a predefined location.     

Living and health conditions of selected cities in India: Setting priorities for the National Urban Health Mission

The concept of “healthy city” promotes the physical, mental, social, and environmental well-being of people who live and work in urban areas. Fostering sustainably healthy cities is the prime objective of the National Urban Health Mission (NUHM) in India. However, attaining this goal requires establishing priorities, key concerns, strategies and guidelines for action. This paper aims to assist policymakers by providing critical insights into the health and living conditions in selected major cities in India, with special emphasis on slums. This paper presents evidence that many of India’s major cities face significant deficits in the provision of basic amenities, including shelter, safe drinking water, improved sanitation and electricity. Demographic and health conditions in these cities lag far behind the goals set forth in national policies almost a decade ago. Despite the apparent proximity of city dwellers to urban health facilities, less than one third of the urbanites in India utilize government health facilities.     

Recognizing objects seen from novel viewpoints: Effects of view similarity and time.

View combination refers to a process that allows generalization to novel views of an object by the combination of object views represented in memory. The present experiments examined whether the perceived similarity between views or the temporal separation of views poses constraints on the view combination process. The results indicated that, although similar views are mapped onto the same object more easily than dissimilar views, dissimilar views, when experienced contiguously in time, produce greater generalization after view combination than similar views. These findings suggest that although the mapping of dissimilar views to the same object is difficult, exposure to temporally contiguous dissimilar views produces better generalization than does exposure to similar views, presumably because they provide more structural information about the object. However, view combination appears to be constrained to views experienced contiguously in time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oximetry of retinal vessels by dual-wavelength imaging: calibration and influence of pigmentation

A method for noninvasive measurement of Hb O2 saturation (SO2) in retinal blood vessels by digital imaging was developed and tested. Images of vessels were recorded at O2-sensitive and O2-insensitive wavelengths (600 and 569 nm, respectively) by using a modified fundus camera with an image splitter coupled to an 18-bit digital camera. Retinal arterial SO2 was varied experimentally by having subjects breathe mixtures of O2 and N2 while systemic arterial SO2 was monitored with a pulse oximeter. Optical densities (ODs) of vascular segments were determined using a computer algorithm to track the path of reflected light intensity along vessels. During graded hypoxia the OD ratio (ODR = OD600/OD569) bore an inverse linear relationship to systemic SO2. Compensation for the influence of choroidal pigmentation significantly reduced variation in the arterial SO2 measurements among subjects. An O2 sensitivity of 0.00504 +/- 0.00029 (SE) ODR units/%SO2 was determined. Retinal venous SO2 at normoxia was 55 +/- 3.38% (SE). Breathing 100% O2 increased venous SO2 by 19.2 +/- 2.9%. This technique, when combined with blood flow studies in human subjects, will enable the study of retinal O2 utilization under experimental and various disease conditions.     

Use of Banded Hematite Quartzite (BHQ) in Blast Furnace for Partial Replacement of Quartzite

Hot metal produced through blast furnace (BF) route is still the most preferred route in majority of the steel industries. In the blast furnace operation, quartzite is used as flux to adjust the desired slag chemistry and basicity (B2 of 1–1.08) to achieve optimum slag properties such as low liquidus temperature, high Sulphur carrying capacity and low viscosity. This paper describes the investigations carried out at JSW Steel Ltd to identify alternate sources of silica other than quartzite for use as flux in BF to maintain the desired slag chemistry for smooth operation and cost reduction. Banded hematite quartzite (BHQ) ore available in Karnataka region contains 28–33% Fe, 45–46% silica, 1.3–1.5% alumina and is found suitable for use as partial replacement for quartzite in blast furnaces. Mineralogy and phase analysis of BHQ reveals alternate bands of hematite and silica whereas in lump ore, hematite and silica are uniformly distributed. This phase distribution and reducibility index of BHQ (~66%) affect the softening start temperature by forming fayalite (2FeO·SiO₂) as primary slag. Fines generations are found to be comparatively higher (from 6.3 to 6.4%) but in acceptable range. The Fe content in the BHQ also contributes to the overall Fe input to the furnace favoring an option to reduce the equivalent amount of iron bearing materials in the charge. Plant trials at JSW steel blast furnace #4, indicate an improvement in overall operational performance resulting in increased Fe input per charge, reduction in slag rate by 8 kg/thm due to low alumina input and easier achievement of final slag chemistry.