Machine Tool Crack Detection using Operational Modal Characteristics

Machine tool crack detection is to detect any damages in the tool during machining and to predict the breakage of the tool by identifying the appearance of small cracks in the tool during machining. Machine tool state monitoring is critical for controlling the work piece quality and production continuity in the case of mass production. For assessing tool breakage, machine tool vibration monitoring is a suitable means. The results obtained in FE analysis are validated with experimental data. This work gives a methodology for online crack detection in machine tools. This work presents an experimental technique for measuring modal parameters of a rectangular aluminium plate with cantilever boundary condition using only the output data, with the intention to apply the technique to machine tools. Operational modal analysis is be used for damage detection by determining the depth as well as the position of tool cracks. The results obtained are validated with finite element analysis. To locate the crack, 3D graphs of the normalized frequency in terms of the crack depth and location are plotted. The intersection of these contours gives crack location and crack depth. Out of several case studies conducted the results of one of the case study is presented to demonstrate the applicability and efficiency of the method suggested

Chemical characteristics of aerosols in MABL of bay of Bengal and Arabian sea during spring inter-monsoon: a comparative study

The chemical composition of aerosols in the Marine Atmospheric Boundary Layer (MABL) of Bay of Bengal (BoB) and Arabian Sea (AS) has been studied during the spring and inter-monsoon (March-May 2006) based on the analysis of water soluble constituents (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3- and SO42-), crustal elements (Al, Fe, and Ca) and carbonaceous species (EC, OC). The total suspended particulates (TSP) ranged from 5.2 to 46.6 μg m-3 and 8.2 to 46.9 μg m-3 during the sampling transects in the BoB and AS respectively. The water-soluble species, on average, accounted for 44% and 33% of TSP over BoB and AS respectively, with dominant contribution of SO42- over both the oceanic regions. However, distinct differences with respect to elevated abundances of NH4+ in the MABL of BoB and that of Na+ and Ca2+ in AS are clearly evident. The non-sea-salt component of SO42- ranging from 82 to 98% over BoB and 35 to 98% over AS; together with nss-Ca2+/nss-SO42- equivalent ratios 0.12 to 0.5 and 0.2 to 1.16, respectively, provide evidence for the predominance of anthropogenic constituents and chemical transformation processes occurring within MABL. The concentrations of OC and EC average around 1.9 and 0.4 μg m-3 in BoB and exhibit a decreasing trend from north to south; however, abundance of these carbonaceous species are not significantly pronounced over AS. The abundance of Al, used as a proxy for mineral aerosols, varied from 0.2 to 1.9 μg m-3 over BoB and AS, with a distinctly different spatial pattern - decreasing north to south in BoB in contrast to an increasing pattern in the Arabian Sea

Character association and path coefficient analysis for grain yield of parents and hybrids in rice (Oryza sativa L.)

An experiment was conducted to study the inter-relationships, direct and indirect effects of various yield attributing characters towards grain yield per plant, at Rice Research Centre, Rajendranagar. Grain yield per plant had significant positive correlation with productivity per day (0.97), panicle weight (0.71), number of filled grains per panicle (0.57), panicle length (0.46), number of productive tillers per plant (0.34), days to 50 per cent flowering (0.23) and plant height (0.16).Path analysis revealed that productivity/ day (0.91) was the major contributor for grain yield followed by, days to 50 per cent flowering (0.19), grain length (0.05), number of productive tillers per plant (0.04), panicle weight (0.04) and number of filled grains per panicle (0.04). It can be concluded from the study that, the above characters can be used as the selection criteria in any rice yield improvement breeding programmes

A short review of use of nanotechnology in periodontics

Nanoscience or nanotechnology refers to the development and research of an applied science at the atomic or molecular level. Nanotechnology is developing fast in recent years and like other medical fields it is also set to transform dentistry in a huge way. It is now considered as a multidisciplinary field of scientific research. Different types of nanomaterials, nanoparticles, nanodivices and its applications are of human interest. Nanodentistry can make maintenance of oral health by employing the nanodivices which will allow precise control on various techniques in oral care like oral analgesia, dentine replacement therapy, permanent hypersensitivity cure, periodontal cure and complete orthodontic realignment etc. Nanotechnology and its application in periodontics have improved the diagnosis, treatment, prognosis and prevention of the periodontal diseases. It utilizes nanomaterials, nanobiotechnology and nanorobots for the treatment and maintenance of periodontal health. The purpose of this paper is to review the phenomenon of nonotechnology as applied to periodontics

A Quantitative Approach to Prioritize Sustainable Concrete

Cement industry consumes high energy and produces major emissions to the environment. In order to reduce the effects (environmental impact, energy, and resources) caused by conventional materials, various by-products and pozzolonic material are used to achieve sustainable concrete. Assessing the concrete performance based on multiple conflicting attributes is decisive and compelling. It is difficult to choose an alternative among the Supplementary Cementitious Materials (SCM) considering a set of quantitative performance attributes. Hence, the present study utilizes the theories of decision making to prioritize an alternative environmentally and technologically. The purpose of the present study is to observe the sustainable performance of five different concretes made of OPC, Fly ash, GGBS, Metakaolin and Composite Cement for a particular grade of concrete. The study has considered workability, strength attribute (compressive strength, split tensile and flexural strength) and durability attribute (Sorptivity and RCPT) at their respective optimum replacements. To prioritize an alternative material considering quantitative attributes, Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is utilized. From the results, it is observed that considering all attributes, flyash based concrete has higher performance and is prioritized among others. The developed approach facilitates the decision-makers in the selection of a sustainable alternative

Heterosis studies in rice for the identification of better hybrids for Telangana, India

In the present study, 23 elite rice genotypes were test crossed with IR 58025A and based on which, 12 restorer lines viz., Rajendra, MTU 1010, IR 64, KNM 118, NLR 33358, Satya, Varalu, RNR 15048, RNR 15038, Tel- lahamsa, RNR(RK) 28 and RNR(RK) 53 were identified during Kharif- Rabi 2013-14. Then, three CMS lines viz., IR 58025A, IR 68902A and IR 72081A were crossed with these identified 12 restorer lines to produce 36 hybrids in line × tester mating design and were evaluated along with standard hybrid check, PA 6129 at Rice Research Centre, Rajendranagar, during Kharif 2014 to find out the best heterotic combinations in terms of grain yield and yield component characters. The degree of heterosis varied from trait to trait. Out of 36 hybrids studied, the significant standard heterosis for grain yield is observed in 3 hybrids, over best check PA 6129, viz., IR 58025A × MTU 1010 (18.25), IR 68902A × RNR 15038 (14.59) and IR 72081A × RNR 15038 (9.57). The best experimental hybrid IR58025A × MTU 1010 recorded average heterosis (78.26) and heterobeltiosis (64.37). These three experimental hybrids can be further evaluated over locations for large scale commercialization in Telangana