Application of Ultrasonic Pod Models

The ability to quantify the reliability of nondestructive evaluation (NDE) inspection techniques is required to integrate inspectability into the component design process. Inspectability is typically evaluated on the basis of the design engineer’s experience and knowledge of NDE. While this approach can yield adequate designs with regard to inspection reliability, the potential for uninspectability remains. There is also the possibility that the designer’s knowledge of the reliability of NDE techniques may be limited to “standard” approaches which may be be inadequate for new component geometries or materials. This could lead the design engineer to imagine that a given component is inadequately inspectable and to redesign the part when the correct solution is either to modify the inspection protocol or to select a different technique. Alternatively, models which predict inspection reliability could be used to weigh the trade-offs and risks associated with selection among candidate NDE techniques to be applied to inspection of a given component design and to identify NDE system configurations for optimal reliability. This approach is, in fact, a key feature of the Unified Life Cycle Engineering concept currently being developed by the Air Force[l]

Absolute Magnitude of Front Surface Reflections in Ultrasonic Measurements

It has been shown in other papers in this volume (1,2) that the application of deconvolution, diffraction, and attenuation corrections to received ultrasonic signals is sufficient to extract the absolute value of the flaw scattering amplitude from the signal. This capability provides a new opportunity to obtain additional flaw characterization information from the ultrasonic signal. More specifically, it is postulated upon reasonable grounds that the absolute magnitude of the front surface ultrasonic echo from a flaw can be related to both the flaw dimensions and its acoustic impedance. Assuming that the size can be obtained by other means, the front surface echo can then be utilized to help identify the flaw. The purpose of this paper is thus twofold: 1) to utilize the diffraction and attenuation corrections developed by Thompson and Gray (3) to obtain absolute values of flaw impulse responses, and 2) to investigate the feasibility of using absolute values of front surface echoes to determine a flaw’s identity

Dopamine receptor genetic polymorphisms and body composition in undernourished pastoralists: An exploration of nutrition indices among nomadic and recently settled Ariaal men of northern Kenya

<p>Abstract</p> <p>Background</p> <p>Minor alleles of the human dopamine receptor polymorphisms, DRD2/TaqI A and DRD4/48 bp, are related to decreased functioning and/or numbers of their respective receptors and have been shown to be correlated with body mass, height and food craving. In addition, the 7R minor allele of the DRD4 gene is at a higher frequency in nomadic compared to sedentary populations. Here we examine polymorphisms in the DRD2 and DRD4 genes with respect to body mass index (BMI) and height among men in two populations of Ariaal pastoralists, one recently settled (n = 87) and the other still nomadic (n = 65). The Ariaal live in northern Kenya, are chronically undernourished and are divided socially among age-sets.</p> <p>Results</p> <p>Frequencies of the DRD4/7R and DRD2/A1 alleles were 19.4% and 28.2%, respectively and did not differ between the nomadic and settled populations. BMI was higher in those with one or two DRD4/7R alleles in the nomadic population, but lower among the settled. Post-hoc analysis suggests that the DRD4 differences in BMI were due primarily to differences in fat free body mass. Height was unrelated to either DRD2/TaqI A or DRD4/48 bp genotypes.</p> <p>Conclusion</p> <p>Our results indicate that the DRD4/7R allele may be more advantageous among nomadic than settled Ariaal men. This result suggests that a selective advantage mediated through behaviour may be responsible for the higher frequency of the 7R alleles in nomadic relative to sedentary populations around the world. In contrast to previous work, we did not find an association between DRD2 genotypes and height. Our results support the idea that human phenotypic expression of genotypes should be rigorously evaluated in diverse environments and genetic backgrounds.</p

The Value of Participating in British Exploring Society Expeditions: A Three Year Multi Cohort Study

A primary aim of many expeditions is to facilitate personal development of young people and 15 while there is much anecdotal evidence to support this aim, there is limited empirical work of 16 varied quality that explores the specific nature of such benefits. This research examined nine 17 summer BES expeditions (Norway, Namibia & Amazon in 2012; Finnmark, Ladakh and 18 Namibia in 2013 and 2014) involving 58 young people (aged between 15 and 22) who completed 19 three on-line questionnaires to collect qualitative (open ended questions) and quantitative (likert 20 scale) data. Measurement of four psychological attributes associated with effective character 21 development were used: mental toughness, coping skills, GRIT and leadership skills. Surveys 22 were completed at three stages; 1) pre expedition, 2) immediately post expedition and 3) three 23 months post expedition. Results indicated that the expeditions impacted positively on the 24 psychological attributes of young people, with short term effects (three months). 25 For the 58 participants, there were statistically significant improvements and small positive 26 effect sizes in mental toughness (P=.006; ηp 2 .167), leadership skills (P=.004; ηp 2 .18), and 27 GRIT (P=.001; ηp 2 .218). There was no significant difference (P>0.05) or effect size for the 28 application of coping strategies. Qualitative data provided insights into how the learning took 29 place and individual perspectives on the overall value of the expedition in relation to narrative 30 understandin

Type discrimination of Various Welding Defects Created During Production and In-Service Use

Verification of the quality of welded structures, both post-production and in-service, has long been a concern of the engineering, materials and nondestructive communities. Nondestructive techniques have been developed and refined to address this verification problem. Each technique has inherent limitations, however, that in certain situations preclude its use or severely restrict the type of information that may be obtained particularly concerning the flaw type. Of these techniques, x-ray investigation is probably the most versatile in determining flaw type and size at present. The equipment required for x-ray examination, however, place constraints on its use, particularly for in-service structures, from the standpoint of accessibility and personnel safety.</p

ψ(3770)\psi(3770) and BB meson exclusive decay B→ψ(3770)KB \to \psi(3770) K in QCD factorization

Belle has observed surprisingly copious production of $\psi(3770)$ in $B$ meson decay $B\to \psi(3770)K$, of which the rate is comparable to that of $B\to \psi(3686)K$. We study this puzzling process in the QCD factorization approach with the effect of S-D mixing considered. We find that the soft scattering effects in the spectator interactions play an essential role. With a proper parametrization for the higher twist soft end-point singularities associated with kaon, and with the S-D mixing angle $\theta=-12^{\circ}$, the calculated decay rates can be close to the data. Implications of these soft spectator effects to other charmonium production in $B$ exclusive decays are also emphasized.Comment: journal versio

Sexually transmitted infections in Saudi Arabia

BACKGROUND: Data on sexually transmitted infections (STIs) in Saudi Arabia (SA) and other Islamic countries are limited. This study describes the results of a five-year surveillance for STIs in SA. METHODS: This is a case series descriptive study of all confirmed STIs diagnosed in SA from January, 1995 through December, 1999. RESULTS: A total of 39049 STIs were reported to the Ministry of Health. Reported STIs included nongonococcal urethritis (14557 infections, 37.3%), trichomoniasis (10967 infections, 28.1%), gonococcal urethritis (5547 infections, 14.2%), syphilis (3385 infections, 8.7%), human immunodeficiency virus (2917 infections, 7.5%), genital warts (1382, 3.5%), genital herpes (216 infections, 0.6%), and chancroid (78 infections, 0.2%). The average annual incidence of STIs per 100,000 population for Saudis and non-Saudis, respectively, was as follows: 14.8 and 7.5 for nongonococcal urethritis, 9.4 and 10.4 for trichomoniasis, 5.2 and 4.2 for gonorrhea, 1.7 and 6.4 for syphilis, 0.6 and 8.0 for HIV, 1.4 and 0.7 for genital warts, 0.1 and 0.4 for genital herpes, and 0.1 and 0.1 for chancroid. The incidence of STIs was somewhat steady over the surveillance period except for nongonococcal urethritis which gradually increased. CONCLUSION: Nongonococcal urethritis, trichomoniasis, and gonococcal urethritis were the most commonly reported STIs in SA. Even though the incidence of STIs in SA is limited, appropriate preventive strategies that conform to the Islamic rules and values are essential and should be of highest priority for policymakers because of the potential of such infections to spread particularly among the youth

Simultaneous determination of natural and synthetic steroid estrogens and their conjugates in aqueous matrices by liquid chromatography / mass spectrometry

An analytical method for the simultaneous determination of nine free and conjugated steroid estrogens was developed with application to environmental aqueous matrices. Solid phase extraction (SPE) was employed for isolation and concentration, with detection by liquid chromatography/mass spectrometry (LC/MS) using electrospray ionisation (ESI) in the negative mode. Method recoveries for various aqueous matrices (wastewater, lake and drinking water) were determined, recoveries proving to be sample dependent. When spiked at 50 ng/l concentrations in sewage influent, recoveries ranged from 62-89 % with relative standard deviations (RSD) < 8.1 %. In comparison, drinking water spiked at the same concentrations had recoveries between 82-100 % with an RSD < 5%. Ion suppression is a known phenomenon when using ESI; hence its impact on method recovery was elucidated for raw sewage. Both ion suppression from matrix interferences and the extraction procedure has bearing on the overall method recovery. Analysis of municipal raw sewage identified several of the analytes of interest at ng/l concentrations, estriol (E3) being the most abundant. Only one conjugate, estrone 3-sulphate (E1-3S) was observe

Assessing the Criteria for Definition of Perimembranous Ventricular Septal Defects in Light of the Search for Consensus

Background: Discussions continue as to whether ventricular septal defects are best categorized according to their right ventricular geography or their borders. This is especially true when considering the perimembranous defect. Our aim, therefore, was to establish the phenotypic feature of the perimembranous defect, and to establish the ease of distinguishing its geographical variants. Methods and results: We assessed unrepaired isolated perimembranous ventricular defects from six historic archives, subcategorizing them using the ICD-11 coding system. We identified 365 defects, of which 94 (26%) were deemed to open centrally, 168 (46%) to open to the outlet, and 84 (23%) to the inlet of the right ventricle, with 19 (5%) being confluent. In all hearts, the unifying phenotypic feature was fibrous continuity between the leaflets of the mitral and tricuspid valves. This was often directly between the valves, but in all instances incorporated continuity through the atrioventricular portion of the membranous septum. In contrast, we observed fibrous continuity between the leaflets of the tricuspid and aortic valves in only 298 (82%) of the specimens. When found, discontinuity most commonly was seen in the outlet and central defects. There were no discrepancies between evaluators in distinguishing the borders, but there was occasional disagreement in determining the right ventricular geography of the defect. Conclusions: The unifying feature of perimembranous defects, rather than being aortic-to-tricuspid valvar fibrous continuity, is fibrous continuity between the leaflets of the atrioventricular valves. While right ventricular geography is important in classification, it is the borders which are more objectively defined

Using Rasch analysis to form plausible health states amenable to valuation: the development of CORE-6D from CORE-OM in order to elicit preferences for common mental health problems

Purpose: To describe a new approach for deriving a preference-based index from a condition specific measure that uses Rasch analysis to develop health states. Methods: CORE-OM is a 34-item instrument monitoring clinical outcomes of people with common mental health problems. CORE-OM is characterised by high correlation across its domains. Rasch analysis was used to reduce the number of items and response levels in order to produce a set of unidimensionally-behaving items, and to generate a credible set of health states corresponding to different levels of symptom severity using the Rasch item threshold map. Results: The proposed methodology resulted in the development of CORE-6D, a 2-dimensional health state description system consisting of a unidimensionally-behaving 5-item emotional component and a physical symptom item. Inspection of the Rasch item threshold map of the emotional component helped identify a set of 11 plausible health states, which, combined with the physical symptom item levels, will be used for the valuation of the instrument, resulting in the development of a preference-based index. Conclusions: This is a useful new approach to develop preference-based measures where the domains of a measure are characterised by high correlation. The CORE-6D preference-based index will enable calculation of Quality Adjusted Life Years in people with common mental health problems