Development of 0.2C-CrMnMoV Ultra High Strength Steel

A study was carried out to develop a low alloy ultra high strength steel by induction melting and thermomechanical treatment (TMT) containing alloying elements like carbon, manganese, molybdenum, chromium and vanadium. A base alloy was prepared with 0.24%C, 1.16% Mn, 0.23% Si, 5.61% Cr, 0.42%V, 1.01% Mo, 0.026%S and 0.032%P. It showed tensile strength of 1467 MPa, yield strength of about 1180 MPa, impact strength of 6.3J and elongation of 5.9% in as-tempered condition. Other alloy was prepared by addition of 0.054% titanium with the base composition. It displayed tensile strength, yield strength, impact toughness and % elongation of 1615 MPa, 1240 MPa, 8.2J and 6.15%, respectively. The optical, SEM and TEM microstructures confirmed that the base alloy and the titanium alloy consisted with tempered lath martensites. The remaining part of the ingot was further processed by the thermomechanical treatment. The ingots were rolled in two passes, initially at 950 C and subsequently at 850 C followed by immediate cooling in oil. The TMT plates of the base alloy confirmed the tensile strength of 1755 MPa, yield strength in excess of 1460 MPa and impact strength of 9.1J. The titanium added TMT plate displayed tensile strength of 1860 MPa, yield strength of 1580 MPa and impact strength of 10.1J. Microstructures of titanium added alloy consisted finer lath martensite and precipitates of titanium carbides/carbonitrides. It was observed that the addition of titanium significantly improved the mechanical properties of 0.2C-Cr Mn Mo V alloys and the mechanical properties were also improved significantly by thermomechanical treatment

Sensitivity in Nanomechanical Pedestal MEMS Cantilever

Nanomechanical resonator-based sensing devices are used in medical diagnostics based on their high-frequency dynamic behavior. Cantilevers fall into the category of Nanomechanical resonators. It also resembles a resonator whose shape is like that of a nanowire clamped at one end. As the surface-to-volume ratio of a nanowire resonator increases due to scaling down, surface stress plays a crucial role in the mechanical behavior of a resonator. Piezoresistive MEMS cantilevers are used for vapor phase analysis of volatile compounds and gas. Studies were done to address the mass sensitivity issues and fractures associated with bioceramic and nanocomposite coatings-based cantilever resonators. The studies show how the sensing performance can be determined or tuned. Nanomechanical studies of thin films of SiCN on silicon were performed. The sharpness of the tip was found to have an influence on the tip-sample conduction mechanism useful for MEMS applicationsComment: 16 pages, 6 Figure

Dynamics of acid phosphatase production of the ectomycorrhizal mushroom Cantharellus tropicalis

Isolates of the ectomycorrhizal fungus Cantharellus tropicalis were grown in axenic culture to study the effect of pH, temperature, nitrogen source, carbon source, phosphorus source and heavy metals on the production of acid phosphatase and mycelial growth. The results of present study showed optimum mycelial growth with pH 4 at 15 and 35±2 o C. The ectomycorrhizal mushroom mycelia utilized lactose and yeast extract as best carbon and nitrogen source for biomass production. Ferrous sulphate supported the maximum mycelial growth when different trace and heavy metal were tested. Among the phosphorus sources, di-Sodium hydrogen phosphate supported maximum growth. The acid phosphatase production did not follow a uniform pattern as inferred from the observations in this study. High biomass did not mean high acid phosphatase production. However, pH 5 at 15 and 35±2 o C supported high enzyme production. Fries Das medium supplemented with Inositol and yeast extract produced maximum acid phosphatase in in vitro studies. Ferric chloride produced considerably higher acid phosphatase among different trace elements tested. The present study demonstrates various factors of acid phosphatase production, an important feature for selecting ectomycorrhizal mushrooms for field inoculations

Exploration of anticancer potential of hydroxamate derivatives as selective HDAC8 inhibitors using integrated structure and ligand based molecular modeling approach

Recently, histone deacetylase inhibitors are evolving as an exhilarating new class of promising antitumor agents for the treatment of multiple malignancies. It may play a pivotal role as a therapeutic target for challenging the globally wide spread disease, cancer. At the same time, the prediction of biological activity of novel compounds, which was once a major challenge in drug design, is also pacing up its speed. This computational study has been performed in Schrodinger suite packages such as sitemap generation, grid formation, Glide for docking, Quikprop for ADME analysis, e-pharmacophore post docking script and Phase for 3D QSAR models designing, that all are available in Maestro version 9.3. Docking not only helps in predicting the preferred orientation of ligand with its target receptor, but also the binding affinity between the ligand and receptor. The application of Phase and e-pharmacophore script predicts some computational models of the provided ligands using 3D QSAR method. This decreases the cost and time of biological experiments. Glide XP reveals that compound 21 with the highest score value as the best compound from the dataset. Also, it shows good R2=0.9834, Q2= 0.7753, stability = 0.5407 and low standard of deviation SD=0.1085 for hypothesis ADDRR.1601, for the PLS factor 5. The outcome of these studies suggests compound 21 as a potential drug molecule for HDAC targets

Study of eco-processed pozzolan characterization as partial replacement of cement

Eco-processed pozzolan (EPP) is a sustainable product recycled from spent bleaching earth (SBE). It is recently used as a blended cement. The pretreatment method of palm oil generates SBE as waste material in the refinery plant. Despite sending the SBE to the landfill, which can lead to environmental pollution, it is extracted to produce sustainable products. The physical, chemical, mineralogical, and microstructural characteristics of EPP were analysed. Furthermore, the conventional cement was substituted with 20% of EPP by cement mass in mortar. The compressive strength of mortar containing EPP was determined for the assessment of strength activity index (SAI) of EPP. EPP consists mainly of silica (SiO2), and the value of SiO2, aluminium oxide (Al2O3), and iron oxide (Fe2O3) combination was 68.98% which is more than 50%. According to the ASTM C618 standard, EPP could be categorised in the Class C pozzolan. The major crystalline phase of EPP was αquartz. Based on the micrograph image, EPP possesses some relatively spherical, irregular shaped, and agglomeration of its particles. At an early curing age, the compressive strength of the mortar was increased with the inclusion of 20% of EPP. A high value of SAI can be reached by mortar specimen with 20% of EPP

Influence of firing temperature on the physical, thermal and microstructural properties of kankara kaolin clay: a preliminary investigation

In this study, natural deposits of Kankara kaolin clay were collected and investigated in order to determine physical, microstructural, thermal, and firing properties and assess clay's suitability as starting material for various ceramic applications. Chemical analysis of the clay was performed using XRF. Mineralogical analysis and thermal analysis of the clay were conducted using XRD and thermogravimetric thermal analysis (TGA)/differential thermal analysis (DTA), respectively. In order to assess its ceramic behavior, the clay was fired at 900-1200 °C. Maturation characteristics of fired ceramics were assessed by measuring bulk density, apparent porosity, and shrinkage. It was found that main oxides in the clay are alumina, silica, and potassium oxide, while other oxides are present in trace quantities. Kaolinite, quartz, and illite are the phases found from the XRD results, while mullite ceramic phase formed at firing temperature above 1100 °C. Maturation tests showed that ceramic properties such as bulk density and shrinkage increase with temperature, while apparent porosity decreases with temperature. The results presented in this study prove that the clay is an appropriate material for producing traditional ceramics

Remaking Africa's informal economies: youth, entrepreneurship and the promise of inclusion at the bottom of the pyramid

In recent years, the quest for 'inclusive markets' that incorporate Africa's youth has become a key focus of national and international development efforts, with so-called bottom of the pyramid (BoP) initiatives increasingly seen as a way to draw the continent's poor into new networks of global capitalism. SSA has become a fertile frontier for such systems, as capital sets its sights on the continents vast 'under-served' informal economies, harnessing the entrepreneurial mettle of youth to create new markets for a range of products, from solar lanterns and shampoo to cook stoves and sanitary pads. Drawing on ethnographic research with youth entrepreneurs, we trace the prcesses of individual and collective 'transformation' that the mission of (self-) empowerment through entrepreneurship seeks to bring about. We argue that, while such systems are meant to bring those below the poverty line above it, the 'line' is reified and reinforced through a range of discursive and strategic practices that actively construct and embed distinctions between the past and the future, valuable and valueless, and the idle and productive in Africa's informal economies

Morphometric evaluation of seminiferous tubule and proportionate numerical analysis of Sertoli and spermatogenic cells indicate differences between crossbred and purebred bulls

Aim: The present study compared the testicular cytology and histology between crossbred (Holstein–Friesian [HF] × Tharparkar) and purebred (HF and Tharparkar) bulls to find out differences if any. Materials and Methods: Four peripubertal bulls from each breed were utilized for the study. Through percutaneous needle aspiration biopsy, Sertoli and spermatogenic cells were extracted, and morphometry was studied. For histological studies, testicular tissues obtained through unilateral castration were utilized. Sertoli cells specific GATA4 antibody was used to study the population of Sertoli cells in the seminiferous tubule through immunofluorescence. Results: The testicular weight, volume, and scrotal circumference differed significantly among the breeds. The diameter and area of the seminiferous tubule was high in HF, followed by Karan Fries (KF), and Tharparkar bulls. However, the degree of compactness, based on qualitative evaluation, was high in Tharparkar followed by KF and HF bulls. The intensity of Leydig cells was higher in Tharparkar bulls followed by KF and HF. The proportion of Sertoli cells was higher (p<0.05) in HF and Tharparkar bulls compared to KF bulls. Conclusion: It may be concluded that variations exist in testicular components of the breeds studied and the proportion of Sertoli cells in relation to spermatogenic cells was significantly lower in crossbred bulls compared to purebred bulls

Eureka and beyond: mining's impact on African urbanisation

This collection brings separate literatures on mining and urbanisation together at a time when both artisanal and large-scale mining are expanding in many African economies. While much has been written about contestation over land and mineral rights, the impact of mining on settlement, notably its catalytic and fluctuating effects on migration and urban growth, has been largely ignored. African nation-states’ urbanisation trends have shown considerable variation over the past half century. The current surge in ‘new’ mining countries and the slow-down in ‘old’ mining countries are generating some remarkable settlement patterns and welfare outcomes. Presently, the African continent is a laboratory of national mining experiences. This special issue on African mining and urbanisation encompasses a wide cross-section of country case studies: beginning with the historical experiences of mining in Southern Africa (South Africa, Zambia, Zimbabwe), followed by more recent mineralizing trends in comparatively new mineral-producing countries (Tanzania) and an established West African gold producer (Ghana), before turning to the influence of conflict minerals (Angola, the Democratic Republic of Congo and Sierra Leone)