Design and analysis of effective graded microwave absorbing material for low observable technology

629-634Compositional designing of effective graded radar absorbing material for low observable technology is always a challengeable task in material science. The micro scale or quantum scale interaction of electromagnetic radiation is depends on the characteristic property of each atom or their assembly in a material composition. The filler and matrix in a composite structure plays a vital role between the advantages in electromagnetic absorption capability and the disadvantage due to difficulties in practical homogenous dispersion with weight concentration. The present work describes synthesis of biomaterial based effective graded radar absorbing material (RAM) for application in stealth technology. Ultrasonic treated rice husk raw material shows a significant increase of dielectric property of the composite material blended with epoxy resin. The significant modification in surface of the biomaterials with ultrasonic wave provides the enhanced mechanical strength as well as hardness of the material. Bio ceramic material composed of china clay and carbon rich waste rice husk ash possesses good dielectric loss for frequency 10 GHz and reflection loss -24.5 dB which is quite significant for stealth technology. Scanning electron microscopy (SEM) study shows good dispersion of rice husk ash in the epoxy matrix. Frequency dependence of both dielectric constant and dielectric loss are measured in the X band frequency range (8.2-12.4GHz). This low cost laboratory scale synthesized RAM find its application in designing of stealth aircraft and jet fighter for military purposes

Design and analysis of effective graded microwave absorbing material for low observable technology

Compositional designing of effective graded radar absorbing material for low observable technology is always a challengeable task in material science. The micro scale or quantum scale interaction of electromagnetic radiation is depends on the characteristic property of each atom or their assembly in a material composition. The filler and matrix in a composite structure plays a vital role between the advantages in electromagnetic absorption capability and the disadvantage due to difficulties in practical homogenous dispersion with weight concentration. The present work describes synthesis of biomaterial based effective graded radar absorbing material (RAM) for application in stealth technology. Ultrasonic treated rice husk raw material shows a significant increase of dielectric property of the composite material blended with epoxy resin. The significant modification in surface of the biomaterials with ultrasonic wave provides the enhanced mechanical strength as well as hardness of the material. Bio ceramic material composed of china clay and carbon rich waste rice husk ash possesses good dielectric loss for frequency 10 GHz and reflection loss -24.5 dB which is quite significant for stealth technology. Scanning electron microscopy (SEM) study shows good dispersion of rice husk ash in the epoxy matrix. Frequency dependence of both dielectric constant and dielectric loss are measured in the X band frequency range (8.2-12.4GHz). This low cost laboratory scale synthesized RAM find its application in designing of stealth aircraft and jet fighter for military purposes

Integrated nutrient management module to improve productivity and economics of short grain aromatic rice (Oryza sativa)- greengram (Vigna radiata) sequence

The present field study was carried out during 2017–18 and 2018–19 rainy (kharif) and winter (rabi) seasons in order to examine the impact caused by integrated nutrient management (INM) on the yield and quality of the short grain aromatic rice (Oryza sativa L.)-greengram (Vigna radiata L.) combination. Two years experimental data concluded that integration of 50% recommended dose (RD) as fertilizer + 50% RD of nitrogen via farm yield manure (FYM) resulted in considerably higher economic yield (3837.1 and 3917.7 kg/ha) of short grain aromatic rice cv. Nua Acharamati which were at par with 75% RD as fertilizer + green manuring of dhaincha (3438.5 and 3539.1 kg/ha). Pooled data revealed that, residual effect of 50% RD as fertilizer + 50% RD of nitrogen (FYM) and 75% RD as fertilizer + Rhizobium + PSB in greengram recorded the highest number of pods/plant (18.2), seeds/pod (11.3), pod length (9.3 cm), test weight (32.7 g), seed yield (925.7 kg/ha) and stover yield (2240.7 kg/ha) in greengram cv. IPM-02-03. Application of 50% RD as fertilizer + 50% RD of nitrogen (FYM) to aromatic rice recorded the highest hulling recovery (75.8 and 75.5%), milling recovery (68.0 and 68.3%), head rice recovery (60.0, 59.7%) and crude protein content (8.75 and 9.11%) during both of the years experiment being at par with application of 75% RD as fertilizer + green manuring. Economics of the system revealed the highest gross return, net return and B:C ratio by application of 50% RD as chemical fertilizer + 50% RD of nitrogen (FYM) in rice followed by 75% RD as chemical fertilizer + Rhizobium + PSB in greengram

Heat Transfer Enhancement from a Heated Plate with Hemispherical Convex Dimples by Forced Convection Along with a Cross Flow Jet Impingement

In the present study, heat transfer from a small three dimensional rectangular channel due to turbulent jet impinging from a nozzle normal to the main flow at the inlet has been investigated. Hemispherical convex dimples are attached to the bottom plate from where heat transfer calculations are to be performed. Numerical simulations were performed using the finite volume method with […] turbulence model. The duct and nozzle Reynolds number are varied in the range of […], respectively. Different nozzle positions (X/D = 10.57, 12.88, 15.19) along the axial direction of the rectangular duct have been considered. It has been found that higher heat transfer is observed at X/D = 10.57 as compared to the other positions. The heat transfer enhancements with and without cross-flow effects have also been compared. It has been shown that the heat transfer rate with cross-flow is found to be much higher than that without crossflow. Also, the effect of dimples on the heated surface on heat transfer was investigated. The heat transfer is found to be greater in the presence of a dimpled surface than a plane surface

Heat Transfer Enhancement from a Heated Plate with Hemispherical Convex Dimples by Forced Convection Along with a Cross Flow Jet Impingement

In the present study, heat transfer from a small three dimensional rectangular channel due to turbulent jet impinging from a nozzle normal to the main flow at the inlet has been investigated. Hemispherical convex dimples are attached to the bottom plate from where heat transfer calculations are to be performed. Numerical simulations were performed using the finite volume method with SST k– ω turbulence model. The duct and nozzle Reynolds number are varied in the range of 10000 ≤ ReD ≤ 50000 and 6000 ≤ Red ≤ 12000, respectively. Different nozzle positions (X/D = 10.57, 12.88, 15.19) along the axial direction of the rectangular duct have been considered. It has been found that higher heat transfer is observed at X/D = 10.57 as compared to the other positions. The heat transfer enhancements with and without cross-flow effects have also been compared. It has been shown that the heat transfer rate with cross-flow is found to be much higher than that without cross-flow. Also, the effect of dimples on the heated surface on heat transfer was investigated. The heat transfer is found to be greater in the presence of a dimpled surface than a plane surface

Not Available

Not AvailableNot AvailableNot Availabl

Not Available

Not AvailableNot AvailableNot Availabl

Not Available

Not AvailableNot AvailableNot Availabl

Not Available

Not AvailableNot AvailableNot Availabl