Banaras Hindu University

About: Banaras Hindu University is a education organization based out in Varanasi, Uttar Pradesh, India. It is known for research contribution in the topics: Population & Catalysis. The organization has 11858 authors who have published 23917 publications receiving 464677 citations. The organization is also known as: Kashi Hindu Vishvavidyalay & Benares Hindu University.

Effect of tempering temperatures on the mechanical properties and microstructures of HSLA-100 type copper-bearing steels

Abstract: Two copper-bearing high-strength low-alloy (HSLA) steels with chemistry similar to HSLA-100, were made on a laboratory scale, one in an air induction (100 kg) furnace and the other in a vacuum induction (50 kg) furnace. The ingots cast were hot-rolled to 25 mm thick plates which were subsequently austenitized and tempered at different temperatures (400–700°C) for 1 h. Evaluation of mechanical properties and microstructure of as-quenched and tempered plates revealed that substantial improvement in strength (YS-1024 and 1025 MPa; UTS-1079 and 1111 MPa for steels 1 and 2) occurred at the expense of impact toughness on tempering at 500°C owing to profuse Cu precipitation in the matrix. With increase in tempering temperature however, the notch toughness improved considerably, reaching peak values of 53 and 123 Joules (J) at −85°C for steels 1 and 2 at 650 and 700°C tempering temperatures, respectively. The partially recovered matrix and the coarsened Cu precipitates in this temperature range presumably enhanced dislocation movement and notch toughness.

Photobiology and Ecophysiology of Rice Field Cyanobacteria

Abstract: Cyanobacteria (blue-green algae) are phylogenetically a primitive group of gram-negative prokaryotes being the only bacteria to possess higher plant-type oxygenic photosynthesis. They also have the capacity to metabolize CO,, O,, N2 and H2 (1). Fossil evidence dates their appearance to the Precambrian era. Stromatolithic mats composed of cyanobacteria are dated at over 2.8 (or possibly 3.5) X lo9 years and appear nearly identical to those found today (2,3). Cyanobacteria are the largest and most widely distributed group of photosynthetic prokaryotes on earth and as a group are thought to have survived from a wide spectrum of environmental stresses such as heat and cold shock, drought, salinity, nitrogen starvation, photooxidation, anaerobiosis, osmotic and UV stress, erc. (4-6). Cyanobacteria are unique in having a cosmopolitan distribution ranging from hot springs to arctic regions. Cyanobacterial colonization of oceans, lakes, rivers, hot springs and soils, and their presence as symbiotic organisms in fungi and plants demand high variability in adapting to diverse environmental factors. Cyanobacterial populations occupy an important place in both aquatic as well as terrestrial ecosystems and achieve net photosynthesis even at temperatures as low as -7°C (7) and as high as 75°C (8). Members of cyanobacteria also possess a central position in the nutrient cycling largely due to their inherent capacity to fix atmospheric N2 with the help of the enzyme nitrogenase, directly into ammonium (MI4+). a form through which nitrogen enters into the food chain (9). Estimates vary as to the contribution of biological nitrogen fixation (BNF)? to the global nitrogen cycle, but according to one assumption cyanobacteria fix over 35 million tons of nitrogen annually, which is thus available for use by higher plants (10). In several instances the availability of

Tuberculosis of spine.

Abstract: (1967). Tuberculosis of Spine. Acta Orthopaedica Scandinavica: Vol. 38, No. 1-4, pp. 445-458.