Numerical and Experimental Study of the Use of Mineral Pumice in the Core of the Sandwich Panel to Absorb the Shock Wave

Reducing the effects of unwanted shocks and waves is a very common problem in engineering. Some materials, due to their inherent properties, can be used as energy absorbers, such as foams, porous materials, and granular materials. porous granular materials that were considered in this study due to their low density and energy absorption capacity. But to use the granular material as the core of the sandwich panel, you have to think of a way to hold the granules together. In this article, using molding with resin, aluminum and polyurethane foam, an attempt has been made to make cores for sandwich panels from mineral pumice. the use of foam showed better performance than the other two materials. These adsorbents have the property of substrate flexibility and impact absorption and low density of porous materials at the same time. The properties of the core were obtained using a pressure test and used in software. Explosion experiments are free and Abaqus software is used in the simulation. The results show that the panel with a thicker back cover has a better performance in absorbing explosion energy. Increasing the thickness of the core has also increased energy absorption

The Role of Natural Antioxidants in Reducing Oxidative Stress in Cancer

Cancer is considered as one of the main causes of mortality due to disease in the whole world and its prevalence is increasing all over the world. Among the numerous causes of cancer, oxidative stress is one of the typically fundamental events that lead to tumor onset and progression. In this regard, natural antioxidants via regulating oxidative stress functions have indicated the anti-cancer effects in cancers. Although some studies have not only mentioned a direct role for antioxidants in cancer treatment, they have indicated their effects in chemotherapy or radiation therapy of cancer patients. This chapter has partly discussed and summarized the oxidative stress functions in the progression of cancer as well as some natural antioxidant protection mechanisms in this process

Elucidating the warm compression of CoCrCuFeNi high entropy alloy: Modeling and microstructural evolution

The warm compression tests were carried out at various temperatures of 400, 550, and 700 °C and strain rates of 0.01, 0.001, and 0.0001 s−1 to unravel the warm deformation behavior of CoCrCuFeNi high entropy alloy (HEA). The microstructural evolutions were characterized using x-ray diffraction (XRD), differential scanning calorimetry (DSC), a field emission gun scanning electron microscope (FESEM) equipped with energy dispersive spectroscopy (EDS), and electron backscattered diffraction (EBSD) detector. These microstructure studies show a dendritic structure containing a bright phase rich in Cu and a darker phase rich in Fe, Cr, and Co. The solidification and melting points of the bright phase are 1136 °C and 904 °C, respectively and the dark phase nucleates at 1365 °C based on DSC results. A Zener-Hollomon parameter was employed to model and predict the warm compression behavior by calculating the activation energy (∼451 kJ/mol), developing a precise constitutive equation (correlation coefficient: R = 0.99), and constructing a processing map for determining the stable temperature and strain rate (strain rates lower than 10−2.75 s−1 and temperatures between 400 and 700 °C) of the plastic flow behavior of the alloy. The FESEM results confirmed the stability and instability domains predicted by the processing map. Moreover, the EBSD analysis indicated that the continuous dynamic recrystallization (CDRX) grains nucleated in the strain rate of 0.0001 s−1 at temperatures higher than 400 °C. Larger grains were formed at 550 and 700 °C due to lower Z parameters in higher temperatures