Sizing of cracks embedded in sub-cladding using the ultrasonic synthetic aperture focusing technique (SAFT)

This paper deals with the experimental work carried out to demonstrate the feasibility of the ultrasonic Synthetic Aperture Focusing Technique (SAFT) to obtain improved detection and sizing of vertical/inclined (10° and 15° simulated cracks underneath different claddings. Crack heights ranging from 1.68 mm to 19.04 mm underneath stainless steel, Inconel and ferritic steel cladding were sized with an accuracy of ±0.1 to ±0.3 mm. The problems encountered in TOFD with regard to sizing of near-surface cracks was successfully overcome by SAFT. Mis-oriented (inclined) defects embedded below the cladding suffer added disadvantage for ultrasonic detection due to loss of reflected energy due to mis-orientation. Using SAFT even these defects could be sized accurately

Melicodenine I, a new quinolinone alkaloid from <i>Melicope denhamii</i> leaves

<p>A new quinolinone alkaloid, Melicodenine I (<b>1</b>), along with five known compounds, bergapten (<b>2</b>), isoevodionol methyl ether (<b>3</b>), isoevodionol (<b>4</b>), ternatin (<b>5</b>), β-sitosteryl-3-O-β-D-glucopyranoside (<b>6</b>) and a mixture of β-sitosterol and stigmasterol were isolated from <i>Melicope denhamii</i> leaves, and their structures were elucidated using ¹H NMR, ¹³C NMR, 2D NMR and UPLC-qToF-MS.</p

Chemical composition, antibacterial and anticancer activities of volatile oil of <i>Melicope denhamii</i> leaves

<div><p><i>Melicope denhamii</i> leaf volatile oil was isolated by hydrodistillation, and twenty-six constituents comprising 95.95% of the leaf oil were characterised by gas chromatographic techniques. Sesquiterpenes, zierone (22.49%) and α-gurjunene (19.96%), were identified as the major components. <i>M. denhamii</i> leaf oil tested against Gram-positive and Gram-negative bacteria showed significant activity against <i>Bacillus subtilis</i> and <i>Escherichia coli</i>. Anticancer activity of <i>M. denhamii</i> leaf oil against Dalton's lymphoma ascites cells was assessed by trypan blue exclusion and MTT assays, and the oil showed significant cytotoxicity at CD₅₀ of 12.2 μg/mL. Induction of apoptosis on DLA cells by <i>M. denhamii</i> leaf oil was confirmed by morphological observation, nuclear damage and comet assays.</p></div

Time of flight diffraction and synthetic aperture focusing technique for NDT of weldments

The limits of anomaly detection by use of nondestructive testing (NDT) methods are based on the interaction of the material with the applied probing medium. Various methods are employed for detection of anomalies in weldments. Investigations using the radiographic, ultrasonic pulse/echo, time of flight diffraction, and synthetic aperture focusing techniques were carried out on a carbon steel weld pad (thickness 18 mm) with natural anomalies introduced at predetermined locations. The anomalies were first imaged by radiography. The pulse/echo technique, using different parameters, could detect almost all the planar anomalies except a cluster of porosity. Although time of flight diffraction could recognize most of the anomalies, it was not possible to clearly resolve and characterize the cluster of pores and group of cracks. Cracks with cleft edges were almost impossible to identify. The experimental results revealed that time of flight diffraction at a minimum meets code requirements for detection of anomalies. Sizing of length and through-wall extent can be carried out using the initial time of flight diffraction data. Using the synthetic aperture focusing technique, it was possible to resolve and characterize all the anomalies on par with the radiographic information. In addition, two clusters of porosity were distinctly seen, separated by 7 mm. Hence, the reporting criteria of the "ASME Boiler and Pressure Vessel Code" (ASME, 2004) can be satisfied using ultrasonic imaging techniques such as time of flight diffraction and synthetic aperture focusing for detection, sizing and characterization of anomalies in weldments in lieu of radiography. Destructive tests were also employed at a later stage to corroborate and validate the findings of anomalies by NDT methods