Materials Development for Indian Nuclear Power Programme: an Industry Perspective

AbstractMaterials play very crucial role for a safe, reliable and economic operation of nuclear power plants. Materials used in nuclear reactors encounter hostile environment and aggressive media during service, and are expected to retain their structural and metallurgical integrity over a long period of use. The major challenges are the effect of radiation on embrittlement, creep, erosion, corrosion, radiation induced growth, swelling, stress corrosion cracking, hydrogen embrittlement and radioactivity build up. In order to realize a high degree of reliabilit y and at the same time meet the imposing challenges, material specification and acceptance criteria are extremely stringent and the products have to undergo a detailed testing and characterization prior to their use. To ensure the conformance to the specification, processes need to be developed which involves melting the alloy with stringent chemistry control, optimizing thermo-mechanical treatment and modifying heat treatment schedule suitably to achieve mechanical properties.A typical nuclear power plant makes use of nuclear fuel materials such as uranium, structural materials such as zirconium alloys, stainless steels, nickel base alloys as well as low alloy and carbon steels. The paper outlines processing methodologies and gives an overview of some of the structural materials

Frontal plane tibio-femoral alignment and its association with knee pain among patients with early osteoarthritis of the knee in a population presenting to a tertiary hospital in South India

Background: Frontal plane knee malalignment may increase the progression of knee osteoarthritis (OA) and worsen functional capacity.Methods: In our study, the aim was to find the correlation of frontal plane tibiofemoral alignment with knee pain in early OA knee patients. After meeting the inclusion and exclusion criteria, 195 patients with 314 knees (104 females, 91 males) were studied. Clinical and radiological measurements of frontal plane tibiofemoral alignment, using landmark of hip, knee, and ankle, compared with knee pain.Results: The accepted Statistical significance was p<0.05. Patients with 130 knees (41%) were normal alignment, and 184 knees (59%) were abnormal alignment. The mean±SD age in our study was 54.6±8.9 years. The mean±SD BMI in our study to be 25.86±1.96. Mean±SD Q-angle in patients with normal and abnormal alignment was 14.76±1.54 and 14.63±1.9 respectively. There is statistically no significant correlation between BMI and VAS score (r=0.054, p=0.344). Means±SD of mLDFA, mMPTA, mTFA, aTFA, and JOA were 88.86±2.73, 84.96±3.00, 5.96±4.01, 4.55±3.67, and 2.37±1.88 respectively. JOA and mTFA had statistically significant weak positive correlation with VAS (knee pain) score, (r=0.281) (p=0.000) and (r=0.236) (p=0.000) respectively. The rest of the angles were not had statistically significant correlation with VAS score. The mTFA had statistically significant weak positive correlation with all the angles. We found that Frontal plane tibiofemoral alignment correlates with knee pain in patients with early OA. Conclusions: The mTFA may be considered one important criterion in designing treatment and planning surgery for patients with primary osteoarthritis. The Q angle acts as a good alternative clinical tool in assessing frontal plane alignment. BMI was not correlating with knee pain (VAS score)

Application of Taguchi approach and Utility Concept in solving the Multi-objective Problem when

The traditional Taguchi method is widely used for optimizing the process parameters of a single response problem. Optimizationof a single response results the non-optimum values for remaining. But, the performance of the manufactured products isoften evaluated by several quality characteristics/responses. Under such circumstances, multi-characteristics response optimizationmay be the solution to optimize multi-responses simultaneously. In the present work, a multi-characteristics responseoptimization model based on Taguchi and Utility concept is used to optimize process parameters, such as speed, feed, depthof cut, and nose radius on multiple performance characteristics, namely, surface roughness (Ra) and material removal rate(MRR) during turning of AISI 202 austenitic stainless steel using a CVD coated cemented carbide tool. Taguchi’s L8 orthogonalarray (OA) is selected for experimental planning. The experimental result analysis showed that the combination of higherlevels of cutting speed, depth of cut, and nose radius and lower level of feed is essential to achieve simultaneous maximizationof material removal rate and minimization of surface roughness. The ANOVA and F-tests are used to analyze the results.Further, the confirmation tests are conducted and the results are found to be within the confidence interval

Patchy layered structure of tropical troposphere as seen by Indian MST radar

The MST radar observations at Gadanki (13.47° N, 79.18° E) show, almost every day throughout the year, stratified layers of intense reflectivity near the tropopause level (17 km) and also at a couple of levels between 4 km and 10 km. Highest individual reflectivity values occur near 17 km, but they occur for a short while. The region between 11 km and 15 km shows the lowest values of reflectivity alongwith vertical downward motion almost on all days of the year. High values of reflectivity are attributed to the existence of visible or sub-visible clouds; the layered structure of clouds is attributed to inertio-gravity waves with vertical wavelength of 2-3 km. It is suggested that each high reflectivity layer consists mainly of thin sheets and patches of visible and sub-visible cloud material. Hydrometeors inside the cloud material go up and down due to gravity, precipitation-loading, Brunt-Vaisala oscillations, and Kelvin-Helmholtz waves. In these small-scale motions, thin air sheets and patches get formed with sharp temperature and humidity discontinuities through contact cooling, melting, evaporation, condensation and freezing. Also, melting and freezing at low temperatures generate electrical charges in these thin sheets and patches. These thin sheets and patches have vertical dimensions ranging from a few centimetres to several metres and horizontal dimensions of the order of 1km. These thin sheets and patches have corresponding vertical and horizontal discontinuities and sharp gradients in refractive index for the MST radar beam. These show up as regions of high values of reflectivity

Resources of Ribbon Fish and Cat Fish off the South West Coast of lndia

The acoustic surveys and fishing experiments conducted by the research vessels RASTRELLIGER and SARDINELLA of the Pelagic Fishery Project from Ratnagiri to the Gulf of Mannar for the past four years have considerably enhanced our knowledge of the pelagic fishery resources, their abundance and seasonal distribution and possible methods of exploitation (Anonymous 1974, 1975 & 1976). The average annual landings of ribbon fish and cat fish for the past ten years with 78,000tonnes form only 7.7% of the total marine fish production in India

Prawn (Penaeus monodon) seed exploited along the coast of Visakhapatnam and Vizianagaram districts of east coast of Andhra Pradesh

The prawn business proved the best among all the businesses because of its profit earned on investment and high value in export trade. The demand for prawns is increasing day by day. Many prawn and acquaculture farms have come up in Visakhapatnam and Vizianagaram districts of Andhra Pradesh. To meet the demand the fishermen folk started exploitation of prawn seed from the surf zone

Techniques Used in Biometric Authentication - Applicability and Future Scope

In recent past, biometrics has emerged rapidly with its worldwide applications for daily living. Novel trends and new developments have been proposed to obtain and pursue many diverse biometric traits. The ignored challenge in the precedent and potential issues need to be addressed together and intensely integrated. The main objective of the paper is to keep up with the innovative technologies on some current theoretical development as well as fresh trends of biometric applications. The topics covered in this paper reflect well both aspects of development. This paper deals with the techniques used for biometric authentication and their future possibilities. This paper also focus on the applicability, strengths and weaknesses of several biometric recognition systems with a comprehensive review of the developments in this field

Dynamic response of exchange bias in graphene nanoribbons

The dynamics of magnetic hysteresis, including the training effect and the field sweep rate dependence of the exchange bias, is experimentally investigated in exchange-coupled potassium split graphene nanoribbons (GNRs). We find that, at low field sweep rate, the pronounced absolute training effect is present over a large number of cycles. This is reflected in a gradual decrease of the exchange bias with the sequential field cycling. However, at high field sweep rate above 0.5 T/min, the training effect is not prominent. With the increase in field sweep rate, the average value of exchange bias field grows and is found to follow power law behavior. The response of the exchange bias field to the field sweep rate variation is linked to the difference in the time it takes to perform a hysteresis loop measurement compared with the relaxation time of the anti-ferromagnetically aligned spins. The present results may broaden our current understanding of magnetism of GNRs and would be helpful in establishing the GNRs based spintronic devices.Comment: Accepted Applied Physics Letters (In press