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Actively and passively aspirated temperature sensors in a windless environment like greenhouses
No full textWindless environments are prevalent in greenhouses, where precise temperature control is critical to the health of plants and errors in temperature measurement must be avoided. A mathematical model based on heat balance is used to estimate the error in temperature sensors under different conditions and sensor geometries. The model is then applied to two geometries and solved numerically. The sensors used are a T-type thermocouple and a Sensirion SHT 75. Experiments are carried out in a greenhouse prototype to replicate conditions in a greenhouse and validate the error model. Active ventilation of the sensors is provided by a fan and passive ventilation is provided using a model built on the concept of a �solar chimney�. It is shown that even small flow rates can decrease the error shown by unventilated sensors by as much as 10°C. © 2019, Indian Academy of Sciences
Multi-model assessment of trends, variability and drivers of terrestrial carbon uptake in India
No full textA multi- model- based assessment is made to assess the trends and variability in the land carbon uptake in India during the period 1901- 2010. Data from nine models, used in a recent land surface model inter- comparison project called TRENDY, are used for this purpose. Our analysis is focused on the trends and variability in the net primary productivity ( NPP), net ecosystem productivity ( NEP) and net ecosystem exchange ( NEE). The multi- model mean NPP shows a positive trend of 2.03% per decade during this period. The NEP, which is the difference between NPP and heterotrophic respiration, has a mean value of - 0.138 +/- 0.086 PgCyr - 1 over this region. According to our analysis of TRENDY multimodels, the inter- annual variation in NPP and NEP is strongly driven by precipitation, but remote drivers such as El Ni no Southern Oscillation ( ENSO) and Indian Ocean Dipole ( IOD) do not have a strong influence. The water use efficiency ( WUE) shows an increase of about 25% over the 110- yr period. Our multi- model- based estimate of the cumulative NEE is 0.613 +/- 0.1PgC during 1901- 2010, indicating that the Indian terrestrial ecosystem was neither a strong source nor a significant sink during this period. However, we caution that our conclusion is based on a limited set of offline land models, and the results presented here have large uncertainties due to model resolution and parameterisation of various land surface processes, the inadequate validation procedures and the use of limited number of models and land use change data sets. Further investigations using more observational data, rigorous validation using extensive observational data sets and a set of comprehensive coupled models that include several feedbacks between land, atmosphere, ocean and the cryosphere are needed to assess the robustness of our results
Evidence of crustal reworking in the Mesoarchean: Insights from geochemical, U-Pb zircon and Nd isotopic study of a 3.08-3.12 Ga ferro-potassic granite-gneiss from north-eastern margin of Singhbhum Craton, India
No full textEvidences of Mesoarchean crustal reworking are not very common in geological records, being only found from Precambrian terrains like Kaapvaal and Pilbara Cratons where it is preserved as anorogenic/post-collisional granitic activity of 3-3.2 Ga age. The present study focuses on a granitoid unit of similar age, found near the eastern margin of the Precambrian Singhbhum Craton of eastern India. This ellipsoidal, N-S trending, well-foliated granite-gneiss body is found within the polydeformed, metasedimenatry rocks of Singhbhum Group, belonging to the North Singhbhum Mobile Belt. LA-ICP MS U-Pb analysis of zircon grains from one sample give crystallization ages ranging from 3079.4 +/- 6.8 Ma to 3115 +/- 10 Ma. These rocks hereby dubbed as ``Bangriposi Granite Gneiss'', are composed of quartz, alkali feldspar, ferroan biotite (Fe/Fe + Mg: 0.7-0.9), titanite, illmenite, hastingsite, apatite, and numerous U-Th-REE- bearing accessory phases. They have high SiO2 (67-77 wt%) and Na2O + K2O (8.19-9.01 wt%), low CaO (0.35-1.5 wt%), MgO (0.05-036 wt%) and shows enrichment of Nb, Rb, Zr, Y, Th, and REEs, and depletion of Cr, Ni, U, with high FeOt/FeOt, + MgO(similar to 0.9), Ga/Al (2.04-3.51), (La/Yb)(N) (6.5-13), and low Eu/Eu* (0.11-0.47). Geochemically and mineralogically they are categorized as metaluminous to weakly peraluminous (A/CNK: 0.9-1.1) ferro-potassic alkali feldspar granites. These rocks show unequivocal affinities towards `A-type'' granites and from geochemical evidences it is suggested that the parent magma was produced in response to crustal anatexis under low foe with P-T estimates of -900 degrees C and 7-8 kbar. Geochemical modelling has revealed that the probable source was lower crustal amphibolites belonging to the Paleoarchean Older Metamorphic Group, which suffered low degrees (5-15%) of melting. Negative CNd values ( -0.5 to -1.5) are also in favour of reworking of older crust and their Nd isotopic signature bears similarities with other coeval anatectic granites. Bangriposi Granite-Gneiss, along with Mayurbhanj Granite and Bonai Granite, represent a major phase of Mesoarchean anorogenic/post-collisional granitic activity in Singhbhum Craton, indicating the onset of its stabilization. Similar Mesoarchean crustally reworked felsic units are encountered in Pilbara and Kaapvaal cratons suggesting a possibility of correlation with the hypothesized ``Vaalbara'' supercontinent. (C) 2019 Elsevier B.V. All rights reserved
Model of GaSb-InAs p-i-n Gate All Around BioTunnel FET
No full textThis paper investigates the role of a hetero-junction p-i-n gate all around tunnel FET architecture for biosensing applications. The device offers a better sensitivity and has been modeled in terms of various parameters such as surface potential, threshold voltage, and drain current. Analytical modeling scheme relates to the exact resultant solution of the two-dimensional Poisson equation. The shift in the threshold voltage has been considered as the sensing parameter to detect the sensitivity when the biomolecules are immobilized in the cavity region
Origins and diagnostics of the nonequilibrium character of active systems (vol 2018, 123201, 2018)
No full textRecent Advancements in Study of Effects of Nano/Micro Additives on Solid Propellants Combustion by Means of the Data Science Methods
No full textThe efforts of Russian-Indian research team for application of the data science methods, in particular, artificial neural networks for development of the multi-factor computational models for studying effects of additive's properties on the solid rocket propellants combustion arc presented. The possibilities of the artificial neural networks (ANN) application in the generalisation of the connections between the variables of combustion experiments as well as in forecasting of ``new experimental results'' are demonstrated. The effect of particle size of catalyst, oxidizer surface area and kinetic parameters like activation energy and heat release on the final ballistic property of AP-HTPB based propellant composition has been modelled using ANN methods. The validated ANN models can predict many unexplored regimes, like pressures, particle sizes of oxidiser, for which experimental data are not available. Some of the regularly measured kinetic parameters extracted from non-combustion conditions could be related to properties at combustion conditions. Results predicted are within desirable limits accepted in combustion conditions
Phase stability, hardness and oxidation behaviour of spark plasma sintered ZrB2-SiC-Si3N4 composites
No full textDespite significant efforts to develop ultra-high temperature ceramics, the phase stability together with high hardness and oxidation resistance remains to be addressed in ZrB2-SiC based ceramics. ZrB2-20 vol% SiC (ZS20) ceramics with varying amounts of Si3N4 (2.5, 5 and 10 vol%) were processed by multi stage Spark Plasma Sintering (SPS) over a range of temperature (1800-1900 degrees C) for 3 min under 50 MPa. All the ZS20-Si3N4 composites could be densified to more than 98% theoretical density (rho th) after SPS at 1900 degrees C. The XRD, SEM-EDS analysis of the ZS20-Si3N4 composites revealed the presence of reaction product phases (ZrO2, BN, ZrN) along with SiC and ZrB2 major phases. Sintering reactions were proposed to explain the existence of such new phases and extinction of Si3N4. Thermo-Cale software was also used to further confirm the formation of these new phases in the ZS20-Si3N4 samples. The hardness of ZS20-Si3N4 composites varied between 25.50 and 30.56 GPa, in particular, ZrB2-20 vol% SiC-5 vol% Si(3)N(4 )measured with the maximum hardness. In fact, it is the highest ever reported hardness for the ZrB2 composites. Considering oxidation resistance, the weight gain of ZrB2-20 vol%SiC composites decreased (from 13.84 to 9.84 mg/cm(2)) and oxide layer thickness increased (64-128 mu m) after oxidation at 1500 degrees C for 10 h in air. The cross sectional microstructure of oxidized ZS20-Si3N4 composites consists of thick dense outer layer of SiO2, intermediate (ZrO2-SiO2) layer and unreacted bulk. The formation of dense SiO(2 )layer and absence of SiC depleted layer from the oxidized samples are signatures of improved oxidation resistance of Si3N4 reinforced ZrB2-20 vol% SiC
Cluster Formation through Hydrogen Bond Bridges across Chloride Anions in a Hydroxyl-Functionalized Ionic Liquid
No full textSeveral recent studies of hydroxyl-functionalized ionic liquids (ILs) have shown that cation-cation interactions can be dominating these materials at the molecular level when the anion involved is weakly interacting. The hydrogen bonds between the like ions led to the formation of interesting chain-like, ring-like, or distinct dimeric (i. e. two ion pairs) supermolecular clusters. In the present work, vibrational spectroscopy (ATR-IR and Raman) and density functional theory (DFT) calculations of the hydroxyl-functionalized imidazolium ionic liquid C(2)OHmimCl indicate that anion-cation hydrogen bonding interactions are dominating, leading to the formation of distinct dimeric ion pair clusters. In this arrangement, the Cl- anions function as a bridge between the cations by establishing bifurcated hydrogen bonds with the OH group of one cation and the C(2)-H of another cation. Cation-cation interactions, on the other hand, do not play a significant role in the observed clusters
Effect of feeding high fat diet on reproductive parameters in male mice
No full textThe present study attempts to chronicle the series of changes starting from the consumption of high fat diet till reproductive activity in male mice. A marginal increase in body weight was observed in male mice fed with high fat diet with 3-fold increase in total body fat and 1.4-fold increase in adipose tissue. A significant reduction in number and diameter of seminiferous tubules were observed in high fat diet fed mice compared to control mice. FACS analysis of testicular germ cells revealed very high percentage of apoptotic cells (84%) compared to control animals (2-3 %) indicative of reduced spermatogenic activity. In addition, a significant decrease in litter size (11.6%-Control to 3.66%-HFD) indicates that reproductive efficiency in high fat diet fed mice reduced to a great extent. The present study revealed high fat diet alters the fertility in male mice significantly and the first in this process appears to be apoptosis of testicular cells due to increase in ROS
Chitosan-Glycerol Gel as Barrier Formulation for Metal Allergy
No full textMetal-induced allergic contact dermatitis, particularly nickel, affects over 10 of the general population. Herein, chitosan-glycerol gel as protective barrier formulation was synthesized by neutralization reaction with an aim to reduce metal-ion diffusion into the skin to prevent allergy. Active functional groups in chitosan-glycerol gel were able to capture allergenic metal ions present in artificial sweat solution. The efficacy of the barrier formulation against nickel-ion penetration was evaluated ex vivo using pig skin. We found that the percutaneous absorption of nickel ion reduced by 98 when chitosan-glycerol gel was used as a barrier formulation. © Copyright © 2019 American Chemical Society