Globally, rice is one of the most important staple food crops. The most significant metric for evaluating the rice growth and productivity is the Leaf Area Index (LAI), which can be effectively ...monitored using remote sensing data. Hyperspectral remote sensing provides contiguous bands at narrow wavelengths for mapping LAI at various rice phenological stages, and it is functionally related to canopy spectral reflectance. Hyperspectral signatures for different phases of rice crop growth was recorded using Airborne Visible Near-Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG) along with corresponding ground based observations. Ground-based hyperspectral canopy spectral reflectance measurements were recorded with FieldSpec 3 Hi-Res spectroradiometer (ASD Inc., Forsyth County, GA, USA; spectral range: 350–2500 nm) and LAI data from 132 farmer’s fields in Southern India. Among 29 hyperspectral vegetation indices tested, 8 were found promising for mapping rice LAI at various phenological stages. Among all the growth stages, the elongation stage was the most accurately estimated using vegetation indices that exhibited a significant correlation with the airborne hyperspectral reflectance. The validation of hyperspectral vegetation indices revealed that the best fit model for estimating rice LAI was mND705 (red-edge, blue, and NIR bands) at seedling and elongation, SAVI (red and NIR bands) at tillering and WDRVI (red and NIR bands) at booting stage.
Finger millet (
Eluesine coracana
L.) is gaining importance as a food crop with the increasing emphasis on nutritional aspects and drought resilience. However, the average productivity of the crop ...has stagnated at around 2,000 kg ha
−1
in India. Recently released nutrient responsive high yielding varieties are reported to respond better to application of fertilizers/manures. Further, substitution of chemical fertilizers with organic manures to maintain sustainable yields and improve soil health is gaining attention in recent years. Therefore, identifying the appropriate rate and source of nutrition is important to enhance the productivity of finger millet while improving the soil health. A field experiment was conducted during two rainy seasons (July–November, 2018 and 2019) to study the response of finger millet varieties to chemical fertilizers and farmyard manure (FYM) on growth, yields, N use efficiency, N uptake and on soil properties. Two varieties MR-1 and MR-6 were tested with four nutrient management practices
viz.
, unamended control, 100% recommended dose of fertilizers (RDF; 40–20-20 kg NPK ha
−1
), 50% RDF + 50% recommended dose of nitrogen (RDN) as FYM and 100% RDN as FYM. Among the varieties, MR-6 outperformed MR-1 in terms of growth, yield, N use efficiency and N uptake. The yield enhancement was up to 22.6% in MR-6 compared to MR-1 across the nutrient management practices. Substituting FYM completely or half of the fertilizer dose increased the growth and yield of finger millet compared to application of chemical fertilizers alone. Similarly, the average biomass yield, ears m
−2
, grain yield, total N uptake and N use efficiency in response to nutrient management practices followed the order of 100% RDN as FYM > 50% RDF + 50% RDN as FYM > 100% RDF. The soil organic carbon, available N, P, K, and S improved by 25.0, 12.9, 5.7, 6.1, and 22.6%, respectively in the plots under higher rate of FYM application (8 Mg ha
−1
) compared to plots under chemical fertilizers alone. We conclude that substituting chemical fertilizers either completely or by up to 50% with organic manures supplies adequate amounts of nutrients, improves the yield of finger millet, economic returns, and soil properties.
Inconel weldments are widely used in automobile and structural industries. In this study, the joints of Inconel625 are made with CO2 Laser beam welding process. The experimentation is carried out ...with two sets of process parameters varying the laser power and estimating the response of the welded component. Radiography analysis and distortion in the weldments are carried out. Distortion is measured using the Vernier height gauge. The lower the better-quality characteristics are chosen for distortion. The welds are free from flaws and the lower heat input results in the lower distortion.
In this paper forced vibration characteristics of a graphene reinforced polymer composite face sheet sandwich panel with a homogeneous core exposed to non-uniform temperature variation is studied. ...Carbon based materials are highly used in aerospace applications. Further these materials are exposed to different environmental conditions which alters it dynamic characteristics. So, in this paper thermal buckling and forced vibration behavior are studied for different grading patterns, temperature dependent properties and non uniform temperature variation. Here, uniform temperature profile, decreasing temperature profile - heating at one edge, decreasing and increasing temperature profile - heating at two edges, increasing and decreasing temperature profile - heating at middle and camel hump temperature - heating at Centre location of the panels are considered. From the results, it is observed that the temperature distribution at 95% of buckling temperature has reduced the natural frequencies significantly and in the forced vibration response, the sandwich panel in this condition shifts its response curve to the left irrespective of the grading pattern. Further, it is noticed that the velocity response curve of FG-X grading pattern has shifted more compare to UD and FG-O grading pattern.
The present work shows the numerical analysis to study the free vibration characteristics of a sandwich panel in which graphene reinforced polymer composite is used as the face sheet and titanium as ...a homogeneous core exposed to non-uniform temperature variation. As these sandwich panels are exposed to different environmental conditions during their service, the vibration resposne of sandwich panel under thermal environment is studied. The finite element approach is utilized to study the influence of different graphene grading patterns, temperature-dependent properties, and non-uniform temperature variation on the buckling and dynamic behavior of the sandwich panel. The temperature-dependent material property of the non-linear type is considered. The temperature distribution at 95 % of buckling temperature affects the dynamic behavior significantly regardless of the graphene grading patterns. The uniform temperature field and the model heated in the middle of the panel influences vibrational behavior efficiently compared to the camel hump temperature field and heated at an edge of the plate. Further FG-X has higher natural frequencies compared to FG-UD and FG-O grading patterns. Several other obtained responses are discussed in this paper.
