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Entomopathogenic fungi Metarhizium species are generally employed to manage the soil-dwelling stage of insect pests, and are known for their rhizocompetency property. Since this fungus is typically recommended for use in soil, it could potentially be investigated as a bioinoculant to reduce abiotic stress, such as salinity, along with improved plant growth promotion. Salt stress tolerance potential of native Metarhizium isolates was evaluated based on mycelial fresh weight, dry weight, and spore yield. All the isolates were found to tolerate NaCl concentrations (50 mM, 100 mM, 150 mM, 200 mM, 250 mM, and 300 mM) supplemented in the culture medium. Metarhizium anisopliae (AAUBC-M15) and Metarhizium pinghaense (AAUBC-M26) were found to be effective at tolerating NaCl stress up to 200 mM NaCl. These two isolates were analyzed in vitro for plant growth-promoting traits at elevated salt concentrations (100 and 200 mM NaCl). No significant effect on IAA production was reported with the isolate M. pinghaense (AAUBC-M26) (39.16 µg/mL) or in combination with isolate M. anisopliae (AAUBC-M15) (40.17 µg/mL) at 100 mM NaCl (38.55 µg/mL). The salinity stress of 100 mM and 200 mM NaCl had a significant influence on the phosphate solubilization activity, except in the co-inoculation treatment at 100 mM NaCl. The isolates were positive for ACC deaminase enzyme activity. An increase in salt concentration was accompanied by a steady and significant increase in chitinase enzyme activity. Total phenolics (149.3 µg/mL) and flavonoids (79.20 µg/mL) were significantly higher in the culture filtrate of Metarhizium isolates at 100 mM NaCl, and gradual decline was documented at 200 mM NaCl. M. pinghaense (AAUBC-M26) proved to be promising in reducing the salt stress in tomato seedlings during the nursery stage. In the pot culture experiment, the treatment comprising soil application + seedling root dip + foliar spray resulted in improved growth parameters of the tomato plant under salt stress. This study shows that Metarhizium, a fungus well known for controlling biotic stress brought on by insect pests, can also help plants cope with abiotic stress, such as salinity.

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Creep is an irreversible time-dependent deformation in which a material under constant mechanical stress and elevated temperature for a considerably prolonged period of time, starts to undergo permanent deformation. Creep deformation occurs in three stages namely, primary, secondary and tertiary. Out of these three stages, secondary or steady state creep is particularly an area of engineering interest as it has almost a constant creep rate. Creep deformation plays a significant role in understanding effective service life of an engineering component working under high temperature conditions as such components such as super-heater and re-heater tubes and headers in a boiler, jet engines operating at temperature as high as 1200 ∘C, usually experience a failure or rupture due to creep phenomenon. Design engineers keep a close attention on working stress conditions and elevated temperature under which an engineering component is expected to work as these conditions determine the onset of creep behavior in an engineering component. By recognizing the parameters of material response to creep behavior, engineers can analyse the useful service life and hazardous working conditions for an engineering components. Recognizing the creep phenomenon as high temperature design limitation, ASME Boiler and Pressure Vessel Code have provided guidelines on maximum allowable stresses for materials to be used in creep range. One of the criteria for determination of allowable stresses is 1% creep deformation of material in 100,000 h of service. Thus, the study of creep behavior in engineering components pertaining to high stress and temperature working conditions is very important as it affects the reliability and performance of the engineering components. The aim of our study is to understand the behavior of secondary creep deformation so that an advanced reinforced functionally graded material with better creep resistance, can be designed. In this paper, a secondary creep analysis of functionally graded (FG) thick-walled rotating cylinder under internal and external pressure is conducted. The novelty of the model intends to specify secondary creep stresses and strains by employing exponential, linear and quadratic volume reinforcement for SiCp ceramic in Al metal matrix in radial direction. This will help us to understand the effect of volume reinforcement in FG cylinder under internal/external pressure and rotating centrifugal body force by obtaining secondary creep stresses and strains. The response of the FG cylinder with isotropic material is analyzed and the solution for stress–strain rates in radial and tangential directions are obtained in closed form. Comparison of steady state creep stresses and strains under exponential, linear and quadratic volume reinforcement profiles are discussed and presented graphically.

The study presents thermo-mechanical analysis of functionally graded (FG) rotating disc whose material properties, namely, Young’s modulus, density and coefficient of thermal expansion in radial direction are tailored from inner to outer radius using power law form. The disc is considered to be under the influence of internal pressure, centrifugal body force and thermal loading of the form linear as well as quadratic. Response of FG disc under linear and quadratic temperature profile subjected to internal pressure as well as centrifugal body force is analysed. An exact solution for stress in radial and tangential directions, under mechanical and thermal loading is presented. Numerical solutions for stresses under internal pressure with uniform thermal loading are obtained using finite element method and its comparison with analytical results is presented graphically. Results for radial displacement, radial stress and tangential stress are depicted graphically and their interpretation has been discussed.