Optimizing chlorophyll meter (SPAD) reading to allow efficient nitrogen use in rice and wheat under rice-wheat cropping system in eastern India

Conventional agricultural practices that rely heavily on blanket fertilizer recommendation, eventually leading to deteriorated partial factor productivity and N use efficiency. We investigated the effect of SPAD-based N-management on productivity and N use efficiency of rice and wheat in eastern India. Here, in the experiment three SPAD thresholds (34, 36 and 38 in rice and 38, 40 and 42 in wheat) using three N levels (15, 25 and 35 kg N ha−1) in split were incorporated as real-time N management (RTNM), one fixed-time N management (FTNM), farmers’ fertilizer practice (FFP) and control (No fertilizer) were introduced in wet and dry seasons for rice and wheat, respectively, during the years 2010 to 2012. Topdressing with 25 kg N ha−1 at medium SPAD (S36 in rice and S40 in wheat) increased soil N availability, leaf N content and grain yield of rice (5215 kg ha−1) and wheat (4483 kg ha−1) over the grain yield recorded under a low rate of N topdressing at low SPAD. While saving 33.3% N in rice and 18.8% N in wheat, the agronomic N use efficiency (58.5% in both rice and wheat) and nitrogen recovery efficiency (32.2% in rice and 15.1% in wheat) can be increased when compared with conventional FTNM. The SPAD-based management strategy showed great promise in efficient management of N fertilizer, and we estimated the optimal SPAD threshold for rice and wheat as 37.5 and 41.8, respectively

Copper Alloy-Impregnated Carbon-Carbon Hybrid Composites for Electronic Packaging Applications

Porous carbon-carbon preforms, based on three-dimensional networks of PAN (Polyacrylonitrile)-based carbon fibers and various volume fractions of chemical vapor-deposited (CVD) carbon, were impregnated by oxygen-free, high-conductivity (OFHC) Cu, Cu-6Si-0.9Cr, and Cu-0.3Si-0.3Cr (wt pct) alloys by pressure infiltration casting. The obtained composites were characterized for their coefficient of thermal expansion (CTE) and thermal conductivity (K) along the through-thickness and two in-plane directions. One composite, with a 28 vol pct Cu-0.3Si-0.3Cr alloy, showed outstanding potential for thermal management applications in electronic applications. This composite exhibited approximately isotropic thermal expansion properties (CTE = 4 to 6.5 ppm/K) and thermal conductivities (k greater than or equal to 260 W/m K)

Microstructure and interfacial reactions during active metal brazing of stainless steel to titanium

Microstructural evolution and interfacial reactions during active metal vacuum brazing of Ti (grade-2) and stainless steel (SS 304L) using a Ag-based alloy containing Cu, Ti, and Al was investigated. A Ni-depleted solid solution layer and a discontinuous layer of (Ni,Fe)2TiAl intermetallic compound formed on the SS surface and adjacent to the SS-braze alloy interface, respectively. Three parallel contiguous layers of intermetallic compounds, CuTi, AgTi, and (Ag,Cu)Ti2, formed at the Ti-braze alloy interface. The diffusion path for the reaction at this interface was established. Transmission electron microscopy revealed formation of nanocrystals of Ag-Cu alloy of size ranging between 20 and 30 nm in the unreacted braze alloy layer. The interdiffusion zone of β-Ti(Ag,Cu) solid solution, formed on the Ti side of the joint, showed eutectoid decomposition to lamellar colonies of α-Ti and internally twinned (Cu,Ag)Ti2 inter- metallic phase, with an orientation relationship between the two. Bend tests indicated that the failure in the joints occurred by formation and propagation of the crack mostly along the Ti- braze alloy interface, through the (Ag,Cu)Ti2 phase layer

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

On the progenitor of binary neutron star merger GW170817

On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the time of the second supernova (SN). We generate simulated progenitor populations and follow the three-dimensional kinematic evolution from binary neutron star (BNS) birth to the merger time, accounting for pre-SN galactic motion, for considerably different input distributions of the progenitor mass, pre-SN semimajor axis, and SN-kick velocity. Though not considerably tight, we find these constraints to be comparable to those for Galactic BNS progenitors. The derived constraints are very strongly influenced by the requirement of keeping the binary bound after the second SN and having the merger occur relatively close to the center of the galaxy. These constraints are insensitive to the galaxy's star formation history, provided the stellar populations are older than 1 Gyr

Not Available

Not AvailableProsopis juliflora (Swartz) DC., an invasive alien plant species, is known as a threat to biodiversity and ecosystem services world over. It has heavily invaded community grazing lands (CGLs) in the Indian Thar Desert. The present study reports effects of four canopy sizes, (i.e. small, medium, large and no-canopy/open plot), of P. julflora shrub on native vegetation and soil fertility (0–20 cm depth) in the CGLs distributed in Jodhpur, Pali, and Sirohi districts in the Desert. In addition, economic profitability of P. juliflora based three enterprises, (i.e. charcoal making, pod-flour making, and sheep rearing in the grasslands if developed in the CGLs), was evaluated to find out invasion control measures of the shrub through utilization. Soil organic carbon (SOC), total N, available P and K, and mineral N (NO3⁻–N, NH4⁺–N) and soil-moisture contents were higher under the shrub canopy than in open plot; and they were the highest under the large and lowest under the small canopy sizes. But, light intensity (Lux) declined under the canopy. The decline, however, was the highest under the large and lowest under the small canopy sizes. Composition of native plant species changed and their richness and diversity declined under the canopy, but was higher under the larger canopy size. Economic analyses revealed that investment was the highest (5476US$ha⁻¹) in the charcoal and lowest (486US$ ha⁻¹) in pod-flour enterprise, but gross profit and net present value (NPV) were the highest (10740US$ha⁻¹ and 5264US$ ha⁻¹, respectively) in the charcoal and lowest (895US$ha⁻¹ and 409US$ ha⁻¹, respectively) in pod-flour enterprise. Other economic parameters, like the annuity and internal rate of return (IRR), were also the highest in the charcoal and lowest in pod-flour enterprise suggesting that the charcoal enterprise is economically the most profitable enterprise; and it may control the invasion of the P. juliflora in the Desert.Not Availabl

Not Available

Not AvailableProsopis juliflora (Swartz) DC., an invasive alien plant species, is known as a threat to biodiversity and ecosystem services world over. It has heavily invaded community grazing lands (CGLs) in the Indian Thar Desert. The present study reports effects of four canopy sizes, (i.e. small, medium, large and no-canopy/open plot), of P. julflora shrub on native vegetation and soil fertility (0–20 cm depth) in the CGLs distributed in Jodhpur, Pali, and Sirohi districts in the Desert. In addition, economic profitability of P. juliflora based three enterprises, (i.e. charcoal making, pod-flour making, and sheep rearing in the grasslands if developed in the CGLs), was evaluated to find out invasion control measures of the shrub through utilization. Soil organic carbon (SOC), total N, available P and K, and mineral N (NO3⁻–N, NH4⁺–N) and soil-moisture contents were higher under the shrub canopy than in open plot; and they were the highest under the large and lowest under the small canopy sizes. But, light intensity (Lux) declined under the canopy. The decline, however, was the highest under the large and lowest under the small canopy sizes. Composition of native plant species changed and their richness and diversity declined under the canopy, but was higher under the larger canopy size. Economic analyses revealed that investment was the highest (5476US$ha⁻¹) in the charcoal and lowest (486US$ ha⁻¹) in pod-flour enterprise, but gross profit and net present value (NPV) were the highest (10740US$ha⁻¹ and 5264US$ ha⁻¹, respectively) in the charcoal and lowest (895US$ha⁻¹ and 409US$ ha⁻¹, respectively) in pod-flour enterprise. Other economic parameters, like the annuity and internal rate of return (IRR), were also the highest in the charcoal and lowest in pod-flour enterprise suggesting that the charcoal enterprise is economically the most profitable enterprise; and it may control the invasion of the P. juliflora in the Desert.Not Availabl