Ethnobotanical Survey of Medicinal Plants Used in the Treatment of Dermatogenic Diseases in Chittoor District, Andhra Pradesh, India

An ethno-medicobotanical survey of plants used in the treatment of dermatogenic diseases in Chittoor District, Andhra Pradesh was conducted. The information was collected on the basis of personal interviews with traditional healers, tribal doctors and old women of the society. The investigation revealed that 24 plant species belonging to 18 families and 21 genera are commonly used in the treatment of skin ailments

Intergranular precipitation and chemical fluctuations in an additively manufactured 2205 duplex stainless steel

Fluctuations in energy distribution during additive manufacturing (AM) can result in spatial and temporal thermal transients. These transients can lead to complexities, most significantly when alloys with multi phases are subjected to AM. Here we unveil such complexities in a duplex stainless steel, where we report an unanticipated formation of a Ni-Mn-Si rich phase at grain boundaries and a local fluctuation in Cr and Fe concentrations in regions close to grain boundaries, providing Cr-rich precursors for Cr2N formation after laser powder bed fusion (LPBF). The formation of these phases is believed to be due to severe thermal gyrations and thermal stresses associated with LPBF resulting in a high-volume fraction of ferrite supersaturated with N and Ni, and a high density of dislocations accelerating diffusion and phase transformations

Acicular Ferrite and Bainite in Fe-Cr-C Weld Deposits

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Effects of Heat Affected Zone Softening Extent on the strength of Advanced High Strength Steels Resistance Spot Weld

Resistance spot welds made from Advanced High Strength Steels (AHSS) exhibit Heat Affected Zone (HAZ) softening due to the tempering of pre-existing martensite phase and the consequent decomposition into a mixture of ferrite and cementite. Despite the high strength level for the base metal, the occurrence of HAZ softening may lead to inferior joint strength during Tension-Shear (TS) and Cross-Tension (CT) testing. In this work, we investigated the effects of the HAZ softening on the global loading response for AHSS steels with three different volume fractions of martensite. Microhardness mapping was used as a measure of martensite tempering and extent of softening. Based on the data, the softening was identified in the sub-critical heat affected zone. Hardness drop with the magnitude of 6%, 18%, and 42% was observed in steels with 16%, 52% and 100% of martensite volume fraction (MVF), respectively. In order to model the welded joint loading response using finite element methods (FEM), there is a need to represent the softening in terms of stress-strain relationships. In this work, local stress-strain curves for different weld zones were obtained by scaling the base metal constitutive properties with local hardness ratio. Finite element (FE) simulations of Tension-Shear tests showed that HAZ softening can affect the Tension-Shear load capacity of specimens more significantly when the base metal tensile strength is above 1000 MPa. The paper will discuss the validity of the above finite element approach for describing experimental results and future directions

Catalytic conversion of acrolein and acrylic acid drop-ins for added-value chemicals

Increasing energy demand and global warming are the most pressing challenges for humankind in the 21st century that alerted the scientific community to search for renewable energy sources to replace fossil fuels for energy and chemical production. Valorizing biomass and its derivatives into commodity chemicals and biofuels are considered a sustainable and promising approach for reducing the use of fossil fuels and for the carbon-neutral society as well. Acrolein and acrylic acid, produced from the waste products (i.e., glycerol) of biodiesel industry, are important precursors for a variety of value-added chemicals and biopolymers. Several processes and technologies, especially based on heterogeneous solid catalysts, have been developed for the efficient conversion of acrolein and acrylic acid into desired products. This chapter provides a concise account on the catalytic conversion of acrolein and acrylic acid to useful chemicals, while highlighting key properties of the solid catalysts for achieving high product selectivity. The synthesis and the properties of acrolein and acrylic acid are briefly discussed in this chapter. More efforts must be directed towards developing economically and ecologically viable routes for the efficient conversion of acrolein and acrylic acid under mild processing conditions that could eventually boost the bioplastic industry. © 2022 Elsevier Inc. All rights reserved

Estimation of spatio-temporal temperature evolution during laser spot melting using in-situ dynamic x-ray radiography

Understanding the spatio-temporal evolution of thermal gradient (G) at and velocity (R) of the solid-liquid and liquid-vapor interfaces is critical for the control of site-specific microstructures in additive manufacturing. In-situ dynamic x-ray radiography (DXR) has been used in recent years to probe the evolution of R with high spatial and temporal resolutions. However, the current methods used to measure the temperature (and therefore, G) are inadequate for sub-melt-pool surface measurement (e.g. thermography) or have lower resolution or limited field-of-view (e.g. x-ray diffraction). In this study, we demonstrate a novel approach to estimate the sub-surface temperature distribution and its time evolution with significantly higher resolutions using DXR data. This methodology uses the Beer-Lambert's law as a physical basis and is demonstrated using an in-situ laser spot-melting experiment on Ti-6Al-4V alloy