A vacuum exterior to Maitra’s cylindrical dust solution

Maitra’s shearing, rotating cylindrical dust solution is fitted to a vacuum exterior. There are no closed timelike curves in the interior or exterior.     

Measurements ofE4 matrix elements in152Sm and154Sm

TheE4 transition matrix element from the ground state to the 4⁺ state has been measured in¹⁵²Sm and¹⁵⁴Sm, by comparing relative thick targetγ-ray intensities following Coulomb excitation with 12 MeV⁴He, 24–30 MeV¹⁶O, and 35–40 MeV³²S projectiles. Values for 〈0⁺∥?(E4)∥4⁺〉 of (+0.31 _?0.20 ^+0.12 ) barn in¹⁵²Sm and (+0.50 _?0.12 ^+0.09 ) barn in¹⁵⁴Sm are found.     

On the feasibility of using thermal gradients for active control of interlaminar stresses in laminated composites

In this paper, a method is proposed to actively control interlaminar stresses near the free edges of laminated composites by though-thickness thermal gradients. Theoretical solutions are given for optimal steady-state through-thickness temperature distributions under uniaxial loading that are required to eliminate or reduce the interlaminar stresses below a prescribed level. The optimal solutions are obtained by minimizing appropriate performance indices that are functions of the far-field properties, with respect to the through-thickness temperature differences. In the second part, an experimental investigation is conducted on a glass/epoxy cross-ply laminate with embedded piezoelectric sensors and a thermal heater. Through the experiment, the feasibility of the thermal control of interlaminar stresses is demonstrated.     

Investigating the reaction mechanism and organocatalytic synthesis of α,α'-dihydroxy ketones

A biomimetic TK one-pot reaction using hydroxypyruvate and aldehydes to generate α,α'-dihydroxy ketones in water has recently been described. To investigate this tertiary-amine mediated reaction mechanism two approaches were used. Firstly, (13)C labelled lithium hydroxypyruvate was synthesised and used to establish where hydroxypyruvate is incorporated in the product. In separate experiments reaction intermediates were also successfully intercepted and structurally identified using ESI-MS with tandem mass spectrometry ESI-MS/MS. These studies indicated that two mechanisms appear to be operating, one involving the addition of the tertiary amine catalyst to hydroxypyruvate, the other an aldol-based mechanism. Since the first mechanism may enable facial stereodifferentiation in the addition of intermediates to the aldehyde, a preliminary study on the use of chiral catalysts was performed and the first asymmetric organocatalytic synthesis of α,α'-dihydroxy ketones in aqueous media achieved, in up to 50% ee, using a quinine ether catalyst.     

Preparation and structure of mixed tungsten bronzes containing tin and europium

An isothermal section has been established for the system Eu_xWO₃Sn_yWO₃ at 1000°C from X-ray powder and single-crystal data and Mössbauer spectroscopy and chemical analyses. A single-phase region with the (12 × 3) tetragonal structure has been established. Single-crystal X-ray analysis shows that the Sn and Eu occupy pentagonal tunnel sites. Mössbauer spectroscopy shows that both Sn(II) and Eu(II) are present. The extent of the single-phase field is controlled by two factors: First, the ratio $\text{Eu}\text{Sn}$ must be <1, and second, the supernumerary electron concentration per WO₃ must be <0.6.     

Gel-state NMR investigation of crosslinked poly(methy1 methacrylate) incorporating 13C labeled ethylene glycol dimethacrylate

¹³C labeled ethylene glycol dimethacrylate (EGDMA) was used to form labeled crosslinked PMMA and model ¹³C labeled pendant double bond copolymers. Solution NMR was possible on solvent-swollen samples containing less than 0.5% by weight EGDMA. Spectra confirm significant amounts of singly reacted EGDMA in fully polymerized networks. Peaks arising from the two most likely stereochemical triads (syndi- and heterotactic) were identified but no evidence of cyclic species was observed. Labeled EGDMA allowed observation of the crosslink site at concentrations as low as 0.02 wt-% EGDMA.     

Colour and lighting in hospital design

Little information or guidance has been available to assist the development of a hospital's visual environment. A report on lighting and colour design schemes, accessible to non professionals with responsibility for refurbishment strategies, was required by NHS Estates. Firstly, 20 hospitals were audited to establish a picture of current practice and to identify key issues where colour design could broadly enhance the environment for patients, staff and visitors. Critical areas were outlined in this report, where colour design can be utilised and applied, for the benefit of all users, from ambience to essential legal requirements such as colour contrast for the visually impaired.Provision of staff relaxation rooms that are different in terms of colour and lux levels from immediate work spaces, or thoughtfully designed areas for patients awaiting intensive treatment, have been shown to have some beneficial effects on a sense of well being. Colour and design have not been established as a definite cure for sickness and ill health, but certainly monotony and poor conditions in premises that have not been refurbished with any care, have had a detrimental affect on recovery rates and staff morale. The realisation that a well balanced and attractive environment is of major importance to patients’ health is, in no way new; Florence Nightingale observed that ‘a variety of form and brilliance of colour in the objects presented to patients are an actual means of recovery’.