Finite element modeling of crack detection in aircraft structures using electrical current

Various non-destructive test methods have been developed for the detection of cracks in metallic structures. Electromagnetic non-destructive testing (NDT) is one of the widely used non-destructive methods used for the detection and characterization of cracks. Utilizing the principle of electromagnetic induction, this technique is used in the areas of nuclear, aerospace, power, transport, petroleum and other industries to inspect defects in metallic sheets, plates and tubes that have good electrical conductivity.;Aircraft structures and wings are made of aluminum sheets riveted together. Cracks are often found emanating from the edge of the rivet holes which are covered by the rivets and are difficult to be detected. Electromagnetic NDT, which involves flow of electrical current and a resultant magnetic field, can be applied to detect these cracks.;In this research, a finite element model was developed which utilizes the principle of electromagnetic NDT. Electrical current density analyses were carried out on aluminum plate with cracks of various shapes and sizes, and demonstrated how electromagnetic NDT can help detect cracks emanating from edge of rivet holes

Record of the Trident cuttlefish from Maharashtra coast

Cuttlefish are important fishery resources landed mostly by mechanized trawlers operating along Maharashtra coast. Many new records of cuttlefishes have been reported from Maharashtra over the years

A comparative study of daytime mesopause temperatures obtained using unique ground based optical and meteor wind radar techniques over the magnetic equator

This paper presents the first ever comparison of daytime Mesopause OH rotational temperatures as determined using Meinel (8-3) dayglow emissions with those obtained using the recently established and collocated, meteor radar (SKiYMET) over the magnetic equator in India. The measurements were made over Thiruvananthapuram (8.5° N, 76.5° E, 0.5° N diplat.) for January-May 2005 period. Overall agreement had been good (± 20 K) with all the gross features coming out fairly well. Further, the temperatures estimated using these two techniques, exhibit significant wavelike modulations with periods spanning ~3-65 days with varying phase differences, presumably due to their interaction with the longer period waves like the semiannual oscillation (SAO). The consistency of the temperature variabilities at two different altitudes viz. 87 and 94 km enables investigation of the mesosphere lower thermosphere dynamic coupling

Biochemical and molecular analysis of Camellia sinensis (L.) O. Kuntze tea from the selected P/11/15 clone

Green tea is one of the most important beverages consumed across the world and it possesses various phytotherapeutics. Polyphenol oxidase (PPO) activity, total polyphenols, catechins, amino acid content and enzymatic antioxidants are considered to be potential parameters in tea characterization. P/11/15 clone (Camellia sinensis (L) O. Kuntze) was chosen to analyze the biochemical characterization and to analyze the gene expression pattern. The selected P/11/15 clone (C. sinensis (L) O. Kuntze) possess potent Polyphenol oxidase (49.62 U/mg of protein), sufficient catechin (20.75%), Polyphenol (20.01%), Peroxidase (450.08 μM of O2 formed min−1 g−1 dry weight), Catalase (1.20 μM H2O2 reduced min−1 mg−1 protein) and Super Oxide Dismutase (45.11 U/mg proteins). Flavonoid gene expression reveals ANR (1.66%) and F3H (1.02%) were up regulated in the selected P/11/15 clone. The results obtained suggest that P/11/15 clone showed adequate enzyme levels, thus an increased antioxidant activity

Long-term variability of the low latitude mesospheric SAO and QBO and their relation with stratospheric QBO

Long term variations of low-latitude mesospheric semi-annual oscillation (MSAO) and quasi-biennial oscillation (MQBO) in the zonal wind are studied using observations available from 1977 to 2006. The MQBO showed large inter-annual variability in the phase difference between 77.5 km and 72.5 km indicating such variability in eddy viscosity. Association of these oscillations with stratospheric quasi-biennial oscillation (SQBO) is investigated. In general, the MQBO at 77.5 km is out-of-phase with SQBO and this relation fails during strong and long SQBO. The MSAO at 72.5 km and 77.5 km generally shows strong westward phase during strong eastward phase of SQBO. The most striking feature observed in the present study is the strong modulation of the MSAO by MQBO revealing a non-linear type of interaction with presence of sidebands of the MSAO