Development of integrated database management and expert system for selection of materials to meet durability and damage tolerance requirements(completion Report)

This is the completion report of the project taken under the Grants-in-Aid scheme of the Aeronautics Research and Development Board. This report enunciates in detail the methodology adopted for arriving at the durability and damage tolerance values of materials for spectrum loading conditions. The document also lists the screen print of the demonstration package developed. The framework chosen for the material database is indicated together with a listing of the database structures, database files and format files

Flow Visualisation Studies On Wall Mounted Pitot Type Intake With Splitter Plate

Flow Visualisation Studies Employing Schlieren/Shadowgraph Technique And -Simple Oil Flow Technique Were Carried Out On A Simple Pitot Type Of 1-Btake With Splitter Plate Mounted On Base Plate In The NAL 0 .3m Tunnel . Between The Splitter Plate And The Base Plate, A Heat Exchanger Duct With Wedge Diverters Was Also Simulated . From These Studies, The Effect Of Closure Of The Intake Duct And The Heat Exchanger Duct On The Flow Behaviour Was Qualitatively Determined . It Was Found That Flow Constraint In The Heat Exchanger Duct And Diverter Passages Had Considerable Effect On The Flow Through The Intake

Terminal substituent effects on the reactivity, thermodynamics, and stereoselectivity of the 8π-6π electrocyclization cascades of 1,3,5,7-tetraenes.

M06-2X/6-31+G(d,p) computations are reported for the 8π-6π electrocyclization cascades of 1,3,5,7-tetraenes. The rate-determining step for these cascades is typically the second (6π) ring closure. According to experiment and theory, un- and monosubstituted tetraenes readily undergo 8π electrocyclic ring closure to form 1,3,5-cyclooctatrienes; however, the 6π electrocyclizations of these cyclooctatriene intermediates are slow and reversible, and mixtures of monocyclic and bicyclic products are formed. Computations indicate that di- and trisubstituted tetraenes undergo facile but less exergonic 8π electrocyclization due to a steric clash that destabilizes the 1,3,5-cyclooctatriene intermediates. Relief of this steric clash ensures the subsequent 6π ring closures of these intermediates are both kinetically facile and thermodynamically favorable, and only the bicyclic products are observed for the cascade reactions of naturally occurring tri- and tetrasubstituted tetraenes (in agreement with computations). The 6π electrocyclization step of these cascade electrocyclizations is also potentially diastereoselective, and di- and trisubstituted tetraenes often undergo cascade reactions with high diastereoselectivities. The exo mode of ring closure is favored for these 6π electrocyclizations due to a steric interaction that destabilizes the endo transition state. Thus, theory explains both the recalcitrance of the unsubstituted 1,3,5,7-octatetraene and 1-substituted tetraenes toward formation of the bicyclo[4.2.0]octa-2,4-diene products, as well as the ease and the stereoselectivity with which terminal di- and trisubstituted tetraenes are known to react biosynthetically

How cinchona alkaloid-derived primary amines control asymmetric electrophilic fluorination of cyclic ketones.

The origin of selectivity in the α-fluorination of cyclic ketones catalyzed by cinchona alkaloid-derived primary amines is determined with density functional calculations. The chair preference of a seven-membered ring at the fluorine transfer transition state is key in determining the sense and level of enantiofacial selectivity

Too hot to handle? Analytic solutions for massive neutrino or warm dark matter cosmologies

We obtain novel closed form solutions to the Friedmann equation for cosmological models containing a component whose equation of state is that of radiation $(w=1/3)$ at early times and that of cold pressureless matter $(w=0)$ at late times. The equation of state smoothly transitions from the early to late-time behavior and exactly describes the evolution of a species with a Dirac Delta function distribution in momentum magnitudes $|\vec{p}_0|$ (i.e. all particles have the same $|\vec{p}_0|$). Such a component, here termed "hot matter", is an approximate model for both neutrinos and warm dark matter. We consider it alone and in combination with cold matter and with radiation, also obtaining closed-form solutions for the growth of super-horizon perturbations in each case. The idealized model recovers $t(a)$ to better than $1.5\%$ accuracy for all $a$ relative to a Fermi-Dirac distribution (as describes neutrinos). We conclude by adding the second moment of the distribution to our exact solution and then generalizing to include all moments of an arbitrary momentum distribution in a closed form solution.Comment: 13 pages, 7 figures, MNRAS submitte

Airworthiness Requirements for Type Certification of NALLA (Report No.5-Aircraft Materials and Fabrication Aspects)

This report is Fifth in the series of the TEN Report prepared by NALLA Airworthiness Group to assist the NALLA design team in providing ready information on airworthiness requirements to be met while selecting/ using materials as well as adapting fabrication methods for a light aircraft

A time-series study of percutaneous closure of patent foramen ovale: premature adoption?

To evaluate the impact of National Institute for Health and Care Excellence (NICE) guidance in January 2005 and subsequent trial evidence on the adoption of percutaneous closure of patent foramen ovale (PCPFO).A retrospective time series study was conducted using the Inpatient Hospital Episode Statistics (HES) England. A total of 3801 patients, aged ≥18 and ≤60 years, who had PCPFO from 1 April 2006 to 31 March 2012 in England. Percentage change annualised (PCA) in PCPFO procedure rates between initial NICE guidance and publication of trial results was analysed.Between Quarter 2, 2006 and Quarter 4, 2009, 2163 PCPFO procedures were performed, with an increasing PCA of 48.4%. The procedure rate peaked before the presentation of equivocal results from the first randomised controlled trial (RCT) in late 2010, and declined between Quarter 4, 2009 and Quarter 4, 2011 (PCA=-15.3%). Of more than 2300 patients recruited to three RCTs, only 71 were recruited in English hospitals.PCPFO was rapidly adopted after the publication of initial NICE guidance despite the absence of RCT evidence of efficacy. Very few English patients participated in international RCTs of PCPFO, suggesting that NICE recommendations also failed to encourage the generation of RCT evidence

Airworthiness Requirements for Type Certification of NALLA Report No. 3- Dynamic Tests and Analysis)

This Report is Third in the series of the TEN Reports prepared by NALLA Airworthiness Group to assist the NALLA design team in providing ready information on airworthiness requirements to be met while considering Dynamic Tests and Analysis aspects in the aircraft design

Pre-term pre-labour rupture of membranes and the role of amniocentesis

Pre-labour premature rupture of membranes (PPROM) is defined as rupture of membranes more than 1 hour prior to the onset of labour at <37 weeks gestation. PPROM occurs in approximately 3% of pregnancies and is responsible for a third of all preterm births. Once membranes are ruptured prolonging the pregnancy has no maternal physical advantage but fetal morbidity and mortality are improved daily at early gestations: 19% of those infants born <25 weeks develop cerebral palsy (CP) and 28% have severe motor disability. Those infants born extremely pre term (<28 weeks) cost the public sector £75835 (95% CI £27906–145508) per live birth not to mention the emotional cost to the family. To prolong gestation is therefore the suggested goal: however how and why might we delay birth in those at risk