Preliminary design of the Shuttle-C avionics recovery system

The analysis done in developing a recovery system for the Shuttle-C cargo vehicle is presented. This recovery system is comprised of a reentry capsule which houses the vehicles avionics. The avionics are contained in a single package which is extracted from the capsule by the parachute recovery system. The Shuttle-C will be able to satisfy NASA's design and mission requirements. Included, is an analysis of the structural, thermal protection, and parachute recovery systems. A discussion of the merits of the proposed system is also included

Sport Satellite Account for the UK 2010

The value of sport to the UK economy has grown since 2008 in terms of output. In current (non-adjusted) prices, sport GVA is worth £33.8bn, or 2.7% of economy wide GVA. Sport-related consumer spending is now worth £26.6bn or 3.0% of UK spending but this proportion has remained static since 2008. And employment is 639,000 in the sport economy which, notwithstanding the 1% increase between 2008 and 2010, has fallen as a proportion of total employment to 2.2% from 2.5% in 2008

Homo- and heterodehydrocoupling of phosphines mediated by alkali metal catalysts

Catalytic chemistry that involves the activation and transformation of main group substrates is relatively undeveloped and current examples are generally mediated by expensive transition metal species. Herein, we describe the use of inexpensive and readily available tBuOK as a catalyst for P–P and P–E (E = O, S, or N) bond formation. Catalytic quantities of tBuOK in the presence of imine, azobenzene hydrogen acceptors, or a stoichiometric amount of tBuOK with hydrazobenzene, allow efficient homodehydrocoupling of phosphines under mild conditions (e.g. 25 °C and < 5 min). Further studies demonstrate that the hydrogen acceptors play an intimate mechanistic role. We also show that our tBuOK catalysed methodology is general for the heterodehydrocoupling of phosphines with alcohols, thiols and amines to generate a range of potentially useful products containing P–O, P–S, or P–N bonds

Synthesis, structure, and cytotoxicity studies of oxidovanadium(IV and V) complexes bearing chelating phenolates

The interaction of [VO(acac)2] with 2,6-bis(hydroxymethyl)-4-methylphenol (L1H3) or 6,6/-methylenebis(4-tert-butyl-2-(hydroxymethyl)phenol) (L2H4) in refluxing toluene afforded, following work-up in ethanol, the complexes [VOL1]2 (1) and {[VO(acac)(HOEt)](VO)L2]}2 (2), respectively. Use of 4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]benzoic acid (L3H2) or 4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]benzosulfonic acid (L4H2) with [VOCl3] in refluxing acetonitrile, followed by methanol and THF work-up, afforded the complexes [Et3NH][VO(OMe)L3]2 (3) and [Et3NH][VO(OMe)L4]2 (4), respectively. The interaction of [VOSO4] and L3H2 in refluxing acetonitrile afforded, with extraction into methanol, the complex [VO(OMe)L3]2 (5). The molecular structures of 2, 3 and 5 have been determined; the structure of 1 has been reported previously. The complexes in this study have been determined to be of low toxicity using in vitro cell assays with 50% cytotoxicity values (CC50) values in the range 56 – 126 µM

High optode-density wearable diffuse optical probe for monitoring paced breathing hemodynamics in breast tissue

Significance: Diffuse optical imaging (DOI) provides in vivo quantification of tissue chromophores such as oxy- and deoxyhemoglobin ([Formula: see text] and HHb, respectively). These parameters have been shown to be useful for predicting neoadjuvant treatment response in breast cancer patients. However, most DOI devices designed for the breast are nonportable, making frequent longitudinal monitoring during treatment a challenge. Furthermore, hemodynamics related to the respiratory cycle are currently unexplored in the breast and may have prognostic value. Aim: To design, fabricate, and validate a high optode-density wearable continuous wave diffuse optical probe for the monitoring of breathing hemodynamics in breast tissue. Approach: The probe has a rigid-flex design with 16 dual-wavelength sources and 16 detectors. Performance was characterized on tissue-simulating phantoms, and validation was performed through flow phantom and cuff occlusion measurements. The breasts of [Formula: see text] healthy volunteers were measured while performing a breathing protocol. Results: The probe has 512 unique source–detector (S-D) pairs that span S-D separations of 10 to 54 mm. It exhibited good performance characteristics: [Formula: see text] drift of 0.34%/h, [Formula: see text] precision of 0.063%, and mean [Formula: see text] up to 41 mm S-D separation. Absorption contrast was detected in flow phantoms at depths exceeding 28 mm. A cuff occlusion measurement confirmed the ability of the probe to track expected hemodynamics in vivo. Breast measurements on healthy volunteers during paced breathing revealed median signal-to-motion artifact ratios ranging from 8.1 to 8.7 dB. Median [Formula: see text] and [Formula: see text] amplitudes ranged from 0.39 to [Formula: see text] and 0.08 to [Formula: see text] , respectively. Median oxygen saturations at the respiratory rate ranged from 82% to 87%. Conclusions: A wearable diffuse optical probe has been designed and fabricated for the measurement of breast tissue hemodynamics. This device is capable of quantifying breathing-related hemodynamics in healthy breast tissue

Homo- and heterodehydrocoupling of phosphines mediated by alkali metal catalysts

Catalytic chemistry that involves the activation and transformation of main group substrates is relatively undeveloped and current examples are generally mediated by expensive transition metal species. Herein, we describe the use of inexpensive and readily available tBuOK as a catalyst for P–P and P–E (E = O, S, or N) bond formation. Catalytic quantities of tBuOK in the presence of imine, azobenzene hydrogen acceptors, or a stoichiometric amount of tBuOK with hydrazobenzene, allow efficient homodehydrocoupling of phosphines under mild conditions (e.g. 25 °C and < 5 min). Further studies demonstrate that the hydrogen acceptors play an intimate mechanistic role. We also show that our tBuOK catalysed methodology is general for the heterodehydrocoupling of phosphines with alcohols, thiols and amines to generate a range of potentially useful products containing P–O, P–S, or P–N bonds

Highly selective CO₂ photoreduction to CO on MOF-derived TiO₂

Metal–Organic Framework (MOF)-derived TiO2, synthesised through the calcination of MIL-125-NH2, is investigated for its potential as a CO2 photoreduction catalyst. The effect of the reaction parameters: irradiance, temperature and partial pressure of water was investigated. Using a two-level design of experiments, we were able to evaluate the influence of each parameter and their potential interactions on the reaction products, specifically the production of CO and CH4. It was found that, for the explored range, the only statistically significant parameter is temperature, with an increase in temperature being correlated to enhanced production of both CO and CH4. Over the range of experimental settings explored, the MOF-derived TiO2 displays high selectivity towards CO (98%), with only a small amount of CH4 (2%) being produced. This is notable when compared to other state-of-the-art TiO2 based CO2 photoreduction catalysts, which often showcase lower selectivity. The MOF-derived TiO2 was found to have a peak production rate of 8.9 × 10−4 μmol cm−2 h−1 (2.6 μmol g−1 h−1) and 2.6 × 10−5 μmol cm−2 h−1 (0.10 μmol g−1 h−1) for CO and CH4, respectively. A comparison is made to commercial TiO2, P25 (Degussa), which was shown to have a similar activity towards CO production, 3.4 × 10−3 μmol cm−2 h−1 (5.9 μmol g−1 h−1), but a lower selectivity preference for CO (3 : 1 CH4 : CO) than the MOF-derived TiO2 material developed here. This paper showcases the potential for MIL-125-NH2 derived TiO2 to be further developed as a highly selective CO2 photoreduction catalyst for CO production

The Effect of Gamma Irradiation on the Physiochemical Properties of Caesium-Selective Ammonium Phosphomolybdate–Polyacrylonitrile (AMP–PAN) Composites

Managing certain by-products of the nuclear fuel cycle, such as the radioactive isotopes of caesium: 134Cs, 135Cs and 137Cs is challenging due to their environmental mobility and radioactivity. While a great many materials can isolate Cs+ ions from neutral or basic aqueous solutions via ion exchange, few of these, with the exception of ammonium phosphomolybdate (AMP), function effectively in acidic media. The use of AMP, and its porous composite in polyacrylonitrile (PAN) for management of Cs radioisotopes in various nuclear wastes have been known for decades and are well studied, yet the effects of radiation on the physiochemical properties of such composites have only received limited attention to date. In a previous publication, we demonstrated that a 100 kGy gamma irradiation dose has negligible effect on the ion exchange performance of AMP and AMP−PAN with respect to capacity or kinetics under the Cs+ concentrations and acidity found in spent nuclear fuel (SNF) recycling. As a continuation of this prior study, in this publication we explore the effects of gamma irradiation on the physiochemical properties of AMP and AMP−PAN using a range of characterisation methods. The effects of the same gamma dose on the oxidation state of Mo in AMP and AMP−PAN, the thermal degradation of both AMP and AMP−PAN, combined with a first study into the high-temperature degradation AMP, are reported. The implications of irradiation, its possible mechanism, the conditions present in SNF recycling, and for the end-of-life disposal or recycling of these materials are also discussed

Off-the-Shelf Gd(NO3)(3) as an Efficient High-Spin Metal Ion Polarizing Agent for Magic Angle Spinning Dynamic Nuclear Polarization

[Image: see text] Magic angle spinning nuclear magnetic resonance spectroscopy experiments are widely employed in the characterization of solid media. The approach is incredibly versatile but deleteriously suffers from low sensitivity, which may be alleviated by adopting dynamic nuclear polarization methods, resulting in large signal enhancements. Paramagnetic metal ions such as Gd(3+) have recently shown promising results as polarizing agents for (1)H, (13)C, and (15)N nuclear spins. We demonstrate that the widely available and inexpensive chemical agent Gd(NO(3))(3) achieves significant signal enhancements for the (13)C and (15)N nuclear sites of [2-(13)C,(15)N]glycine at 9.4 T and ∼105 K. Analysis of the signal enhancement profiles at two magnetic fields, in conjunction with electron paramagnetic resonance data, reveals the solid effect to be the dominant signal enhancement mechanism. The signal amplification obtained paves the way for efficient dynamic nuclear polarization without the need for challenging synthesis of Gd(3+) polarizing agents