Thermal comfort in outdoor urban spaces: understanding the human parameter

The research being undertaken seeks to achieve a better understanding of the richness of microclimatic characteristics in outdoor urban spaces, and the comfort implications for the people using them. The underlying hypothesis is that these conditions influence people’s behaviour and usage of outdoor spaces. The initial results demonstrate that a purely physiological approach is inadequate in characterising comfort conditions outdoors, and an understanding of the dynamic human parameter is necessary in designing spaces for public use. The thermal environment is indeed of prime importance influencing people’s use of these spaces, but psychological adaptation (available choice, environmental stimulation, thermal history, memory effect, expectations) is also of great importance in such spaces that present few constraints.     

Understanding the need for pre-injection from permeability measurements: What is the connection?

Pre-grouting ahead of tunnels has three main functions: to control water inflow into the tunnel, to limit groundwater drawdown above the tunnel, and to make tunnelling progress more predictable since rock mass quality is effectively improved. It helps to avoid settlement damage caused by consolidation of clay deposits beneath built-up areas, since towns tend to be built where terrain is more flat, due to the clay deposits. There are so many instances of settlement damage that the profession needs to take note of the need for high-pressure pre-grouting, to use micro-cements and micro-silica additives. The use of highpressure injection may cause joint jacking, but this is local in extent when the rapid pressure decay away from an injection hole is understood. This effect is variable and depends on the geometrical parameters of the joints. This pressure-decay advantage must not be violated by maintaining high pressure when grout flow from the injection hole has ceased. The latter can cause damage to the grouting already achieved. Simplified methods of estimating mean hydraulic apertures(e) from Lugeon testing are described, and from more sophisticated three-dimensional(3 D) permeability measurement. The estimation of the larger mean physical joint apertures(E) is based on the joint roughness coefficient(JRC).Comparison is then made with the empirical aperture-particle size criterion E 4 d95, where d95 represents almost the largest cement particle size. Depending on joint set orientations and on the available micro-cements, the decision must be made of which range of pre-injection pressure should be aimed for,using successive reductions of the water-cement ratio w/c. More simple estimation of permeability, also with depth dependence, can be made with the empirical link between a modified rock mass quality Q and permeability, which is termed QH2 O. The value of this parameter can be based on core-logging or intunnel face logging. The 3 D before-and-after-grouting permeability measurements have been used to justify the quantification of rock mass quality Q-parameter improvement, and the consequent increases in expected P-wave velocity and deformation modulus, for application in dam foundation treatment and its monitoring.     

Atom Probe Tomography of Zinc Oxide Nanowires

Wide-bandgap zinc oxide (ZnO) semiconductors and nanowires have become important materials for electronic and photonic device applications. In this work, we report the growth of well-aligned single-crystal ZnO nanowire arrays on sapphire substrates by chemical vapor deposition and the development of atom probe tomography, an emerging nanoscale characterization method capable of providing deeper insight into the three-dimensional distribution of atoms and impurities within its structure. Using a metal-catalyst-free approach, the influence of the growth parameters on the orientation and density of the nanowires were studied. The resulting ZnO nanowires were determined to be single crystalline, with diameter on the order of 50 nm to 150 nm and length that could be controlled between 0.5 μm to 20 μm. Their density was on the order of high 10⁸ cm⁻² to low 10⁹ cm⁻². In addition to routine characterizations using scanning and transmission electron microscopy, x-ray diffraction, photoluminescence, and Raman spectroscopy, we developed the atom probe tomography technique for ZnO nanowires, comparing the voltage pulse and laser pulse modes. In-depth analysis of the data was carried out to determine the accurate chemical composition of the nanowires and reveal the incorporation of nitrogen impurities. The current–voltage characteristics of individual nanowires were measured to determine their electrical properties.     

An international quality assurance scheme for the quantitation of daidzein and genistein in food,urine and plasma

This quality assurance (proficiency testing) scheme was commissioned to enable the Food Standards Agency (FSA) to determine the quality of analytical results submitted by researchers measuring the concentrations of phytoestrogens in foods and biological fluids in FSA-funded research projects, and also, to demonstrate that FSA-funded laboratories are producing consistent and precise results. Non-FSA-funded laboratories from around the world were also invited to join in the scheme to increase the number participants. A secondary objective was to highlight the most successful methodologies used to analyse phytoestrogens.     

Transfer in artificial grammar learning: A reevaluation.

This article covers methodological and theoretical issues in artificial grammar learning. Arguments that such tasks are mediated by abstract knowledge (e.g., A. S. Reber, see record 1991-00330-001) are based primarily on evidence from transfer experiments, where the surface vocabulary is changed between learning and test items. Because of a number of methodological concerns, the small magnitudes of artificial grammar learning effects generally are difficult to interpret. Possible solutions are offered here. Furthermore, even reliable transfer effects imply neither that subjects have acquired abstract knowledge of the underlying grammar nor that they are performing a process of abstract analogy from memorized whole exemplars. Models that learn only surface fragments of the training stimuli and perform abstraction at test rather than during learning are wholly consistent with transfer phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A single active site mutation inverts stereoselectivity of 16-hydroxylation of testosterone catalyzed by engineered cytochrome P450 BM3

Inversion of stereoselectivity: screening of a minimal mutant library revealed a cytochrome P450?BM3 variant M01?A82W?S72I capable of producing 16?α-OH-testosterone. Remarkably, a single active site mutation S72I in M01?A82W inverted the stereoselectivity of hydroxylation from 16?β to 16?α. Introduction of S72I mutation in another 16?β-OH-selective variant M11?V87I, also resulted in similar inversion of stereoselectivity.     

Role of the alpha-glucanase Agn2p in ascus-wall endolysis following sporulation in fission yeast

During sporulation in the ascomyceteous fungus Schizosaccharomyces pombe, diploid cells undergo differentiation into asci containing four haploid ascospores, which are highly resistant to environmental stresses. Although the morphogenetic processes involved in ascospore formation have been studied extensively, little is known about the molecular mechanism that ensures the release of mature ascospores from the ascus, allowing their dispersal into the environment. Recently, we identified Agn2p as the paralogue of the characterized endo-(1,3)-alpha-glucanase Agn1p, and observed that asci deleted for agn2 are defective in ascospore dispersal. Here, we focus on the cellular and biochemical functions of Agn2p. By placing agn2 under the control of an inducible promoter, we show that expression of agn2 is required for the efficient release of ascospores from their asci. Furthermore, we characterize the enzyme activity of purified recombinant Agn2p and show that Agn2p, like Agn1p, is an endo-(1,3)-alpha-glucanase that produces predominantly (1,3)-alpha-glucan pentasaccharides. Finally, we demonstrate that exogenous addition of purified Agn2p liberated the ascospores from asci deleted for agn2. We propose that Agn2p participates in the endolysis of the ascus wall by hydrolysing its (1,3)-alpha-glucan, thereby assisting in the release of ascospores.     

Photodegradation of tetrahalobisphenol-A (X = Cl, Br) flame retardants and delineation of factors affecting the process

The photoassisted degradation (HPLC-UV absorption), dehalogenation (HPLC-IC) and mineralization (TOC decay) of the flame retardants tetrabromobisphenol-A (TBBPA) and tetrachlorobisphenol-A (TCBPA) were examined in UV-irradiated alkaline aqueous TiO₂ dispersions (pH 12), and for comparison the parent bisphenol-A (BPA, an endocrine disruptor) in pH 4–12 aqueous media to assess which factor impact most on the photodegradative process. Complete degradation (2.7–2.8 × 10⁻² min⁻¹) and dehalogenation (1.8 × 10⁻² min⁻¹) of TBBPA and TCBPA occurred within 2 h of UV irradiation, whereas only 45–60% mineralization (2.3–2.7 × 10⁻³ min⁻¹) was complete within 5 h for the flame retardants at pH 12 and ca. 80% for the parent BPA. Factors examined in the pH range 4–12 that impact the degradation of BPA were the point of zero charge of TiO₂ particles (pH_pzc; electrophoretic method), particle or aggregate sizes of TiO₂ (light scattering), and the relative number of OH radicals (as DMPO–OH adducts; ESR spectroscopy) produced in the UV-irradiated dispersion. Dynamics of BPA degradation (2.0–2.4 × 10⁻² min⁻¹) were pH-independent and independent of particle/aggregate size, but did correlate with the number of OH radicals, at least at pHs 4 to 8–9, after which the rates decreased somewhat at pH > 9 with decreasing adsorption owing to Coulombic repulsive forces between the very negative TiO₂ surface and the anionic forms of BPA (pK_as ca. 9.6–11.3), even though the number of OH radicals continued to increase at the higher pHs.     

De-embedding parasitic components from propagation constant calculations

We present a novel technique for extracting transition structure circuit elements from microwave transmission lines. Using a full-wave Maxwell Equation simulator and microwave circuit software tools, data were generated from a prototype 2.5-dimensional coaxial line-like structure and used as a test vehicle to ascertain the effectiveness of this method. Our results confirm the method's value as a new tool for the design of microwave components.     

The regular polygon detector

This paper describes a robust regular polygon detector. Given image edges, we derive the a posteriori probability for a mixture of regular polygons, and thus the probability density function for the appearance of a set of regular polygons. Likely regular polygons can be isolated quickly by discretising and collapsing the search space into three dimensions. We derive a complete formulation for efficiently recovering the remaining dimensions using maximum likelihood at the locations of the most likely polygons. Results show robustness to noise, the ability to find and differentiate different shape types, and to perform real-time sign detection for driver assistance.