Thermal and acoustic performance of cement fibreboard and bamboo buildings

462-471The present study evaluates the thermal and acoustic performance of building constructed from aerated concrete-cement fibreboards and bamboo composite. The thermal, humidity, ambient, and indoor temperature parameters are analyzed for a 24-hours cycle from April to May and December to January. The average temperature plot shows the maximum indoor temperature does not exceed 28-32 ºC for April to May and 12-16 ºC for December to January for both the buildings. Thermal admittance is observed as 7.3 W/m2K and 12 W/m2K for cement fibreboard and bamboo composite buildings respectively. Outdoor to indoor noise reduction (OINR) values at frequencies ranging from 80 Hz to 4000 Hz are noted and analysed. The maximum noise isolation provided by cement fibreboard and bamboo composite walls are found to be ~40 dBA and 35 dBA at 500 Hz. With proper ventilation and avoidance of direct sunlight in the room, a comfortable atmosphere can be achieved for these building

Diffused metal-insulator transition in NdNiO3 film grown on BaTiO3: Likely evidence of electronic Griffiths phase

This paper reports diffused metal-insulator transitions (MITs) in an oxide with disorder that undergoes a Mott transition. The investigation was carried out in the multilayer film NdNiO3/BaTiO3/SrTiO3 (NNO/BTO/STO), where a large mismatch of lattice constants of NNO with those of BTO leads to strain relaxation and creation of quenched disorder in the NNO film. NNO film in the NNO/BTO/STO multilayer structure shows a broad Mott-type MIT at a temperature T-MI = 160 K from a high-temperature bad metallic phase (1/rho DC d rho DC/dT < 0) with dT a high value of resistivity rho DC approximate to 70 m Omega cm at 300 K to a low temperature insulating phase. Using noise spectroscopy and impedance spectroscopy which can probe the dynamics of the coexisting phases near the MIT, it was observed that in addition to the MIT at T-MI = 160 K, there exists a characteristic temperature T-G %:Z, 230 K well above the T-MI, where large low-frequency correlated fluctuations appear, signifying the appearance of a phase with slow dynamics. T-G signals the onset of a temperature region T-MI < T < T-G with coexisting phases that have been corroborated by the impedance spectroscopy and AC conductivity measurements. It is suggested that the temperature T-G may signify the onset of an electronic Griffiths phase that has been theoretically proposed for Mott transitions with disorder

Archaeoparasitological Strategy Based on the Microscopic Examinations of Prehistoric Samples and the Recent Report on the Difference in the Prevalence of Soil Transmitted Helminthic Infections in the Indian Subcontinent

Archaeoparasitology is a study to acquire data concerning the parasite infection of ancient people through the examination of the specimens obtained in the excavation sites. Although this research has achieved many successes worldwide, there has been few noteworthy reports from South Asia countries. In 2011 to 2016, we thus conducted parasite examinations on Indian archaeological specimens (n = 247) collected at excavation sites of Mature Harappan period (4600–3900 BP) and their contemporary rural Chalcolithic sites. To derive effective strategy of archaeoparasitological works in Indian Subcontinent, our data were analyzed together with previous clinical report on the soil transmitted helminth infection in the Indian Subcontinent. We propose that future paleoparasitological studies in India should be conducted more intensely on ancient specimens from the states of Assam, Bihar, Jammu and Kashmir, Tamil Nadu, Andhra Pradesh and West Bengal etc

Jewels and jewellery in early Indian Archaeology and literature

by Ravindra Singh Bish

Thermal and acoustic performance of aerated concrete- cement fibreboard and bamboo buildings

The present study evaluates the thermal and acoustic performance of ground plus one storey of 1100 sq. ft. building constructed from aerated cement concrete sandwiched between cement fibreboards and composite bamboo building. The thermal, humidity, ambient, and indoor temperature parameters are analysed for a 24-hours cycle from April to May and December to January month. The average temperature plot for the summer season shows the maximum temperature inside both the buildings does not exceed 32 ºC.  Parameters viz. thermal admittance, thermal damping, and daylight illumination have also been evaluated in the current study. Outdoor to indoor noise reduction (OINR) values at frequencies ranging from 100 Hz to 4000 Hz are noted and analysed. The maximum noise reduction provided by cement fibreboard wall and bamboo walls are these walls is found to be ~ 40 dBA and 35 dBA. With proper ventilation and avoidance of direct sunlight in the room, a comfortable atmosphere can be achieved for these buildings, which will help in the reduction in energy consumption of the buildings

Archaeological studies at Dholavira using GPR

A new area at an existing archaeological site of Harappan civilization at Dholavira, Gujarat, India has been studied using ground penetrating radar (GPR). An area of 12,276 m2 was surveyed using 200 MHz antenna at grid spacing of 2–3 m. The soil strata was found to extend mainly up to 3.5–4 m. The survey was conducted during the dry season to collect good signals. Post-processing was carried out to map the bedrock as well as archaeological features. A number of linear features were observed from the 3D image of the subsurface created from the acquired GPR profiles. Unlike residential structures, the large dimensions of these features indicate the likely existence of a series of water structures that may have partly collapsed due to floods at some point. There were some areas full of rubble next to the damaged walls that appeared to be orthogonal to the direction of possible flood from Manhar River.by Silky Agrawal, Mantu Majumder, Ravindra Singh Bisht and Amit Prashan

Emergence of large thermal noise close to a temperature-driven metal-insulator transition

We report that close to a Mott transition there is an emergence of large thermal noise (Sth) which occurs concomitantly with large correlated flicker noise (1/ noise) with significant non-Gaussian content. This was observed in films of NdNiO3 (thickness 15 nm) grown on crystalline SrTiO3 substrates with different crystallographic orientations that show a hysteretic transition from a high temperature metallic phase to a low temperature insulating phase in the temperature range 160 to 211 K depending on the substrate orientation and the heating and cooling cycle. The thermal noise, which is distinct from the flicker noise, deviates from the canonical Johnson-Nyquist value of 4kBTR as measured through the ratio zeta (T)(= Sth(T)4k(B)TR). The ratio. reaches a maximum value of zeta(M) at a temperature T* that is close to but distinct from the metal-insulator transition (MIT) temperature TMI. In all the films near T*, the scaled thermal noise maxima zeta(M) >> 1. The films were found to be largely strain relaxed with residual in-plane and out-of-plane strain as measured by x-ray reciprocal space mapping. It has been observed that the ratio T*/T-MI as well as zeta(M) have a close dependence on the in-plane-strain in the film. The enhanced thermal noise that occurs along with large correlated flicker noise both arise from slow kinetics of relaxation as established from temperature dependence of the correlation time (tau) that gets significantly larger in the temperature range around T *, reaching a maxima at T = T *. It has been proposed that the existence of large noise (both thermal and flicker noise) owes its origin to electronic phase separation (EPS) that exists near the MIT. A physical model has been suggested that EPS near MIT temperature can give rise to a sparse phase of nanometric small pockets of metallic phases (nanopuddles) that are surrounded by and embedded within the minority insulating phase. The nanopuddles act as a source of charge fluctuations and are coupled weakly to the majority metallic phase by tunneling through the layer of the minority insulating phase. Such isolated metallic nanopuddles can be Coulomb charged if the charging energy E-C >= k(B)T and can have slow relaxation of fluctuations acting as a source of large noise. It has been argued that the size distribution of the nanopuddles, their average size , as well as the temperature dependence of their number density Nd can determine the temperature T *

Continuous transition from weakly localized regime to strong localization regime in Nd0.7La0.3NiO3 films

We report an investigation of metal-insulator transition (MIT) using conductivity and magnetoconductance (MC) measurements down to 0.3 K in Nd0.7La0.3NiO3 films grown on crystalline substrates of LaAlO3 (LAO), SrTiO3 (STO), and NdGaO3 (NGO) by pulsed laser deposition. The film grown on LAO experiences a compressive strain and shows metallic behavior with the onset of a weak resistivity upturn below 2 K which is linked to the onset of weak localization contribution. Films grown on STO and NGO show a cross-over from a positive temperature coefficient (PTC) resistance regime to negative temperature coefficient (NTC) resistance regime at definite temperatures. We establish that a cross-over from PTC to NTC on cooling does not necessarily constitute a MIT because the extrapolated conductivity at zero temperature (lim(T -> 0) sigma - sigma(0)) though small (< 10 S cm(-1)) is finite, signaling the existence of a bad metallic state and absence of an activated transport. The value of sigma(0) for films grown on NGO is reduced by a factor of 40 compared to that for films grown on STO. We show that a combination of certain physical factors makes substituted nickelate (that are known to exhibit first-order Mott type transition), undergo a continuous transition as seen in systems undergoing disorder/composition driven Anderson transition. The MC measurement also supports the above observation and shows that at low temperatures, there exists a positive MC that arises from the quantum interference which co-exists with a spin-related negative MC that becomes progressively stronger as the electrons approach a strongly localized state in the film grown on NGO

Trenchless Mechanized Inspection and Retrofitting Strategy for Buried Sewerage Systems

767-775The conventional retrofitting methods of buried sewer pipes require heavy machinery, intensive manpower, and a longer time for rehabilitation. Such methods may also damage the nearby infrastructures and landscapes. The present study explores an integrated trenchless solution for damage identification and mechanized retrofitting of domestic buried sewerage pipelines of diameter ranging from 75 to 300 mm. A front-mounted camera of the retrofitting system assesses the damage inside the sewer pipes. The retrofitting of the damaged part of buried pipe is achieved by impregnation of Glass Fiber Reinforced Polymer (GFRP) composite sheet with 100:16 epoxy and hardener ratio. The wrapping of the GFRP sheets on damaged part is done by inflation and deflation technique with a cylindrical rubber bladder connected by a flexible shaft. The retrofitted sewer pipe can be resumed after 3–4 hours of applying the impregnated GFRP composite with above retrofitting strategy