Design Margins: Impact on Building Energy Performance

This paper examines the addition of design margins for building services energy infrastructure during the design process. It argues that care must be taken when applying margins; ensuring cumulative effects do not undermine the ability of systems to be energy efficient. An example of a hospital Trust is provided showing the addition of design margins impacting the energy efficiency of services provided. Tensions are found between delivery of flexibility, adaptability and other change parameters and the need for the system to be bounded, so as to encourage effectiveness

Review of methods for deriving areal reduction factors

The design of hydraulic structures requires knowledge of how much rain is likely to fall within a certain amount of time, and over a specific area. Point rainfalls are only representative for a very limited area, and for larger areas the areal average rainfall depth is likely to be much smaller than at the point of maximum observed depth. The estimation of areal reduction factors is concerned with the relationship between the point and areal rainfalls. This relationship has been found to vary with, for example, predominant weather type, season and return period. Methods for estimation of areal reduction factors include empirical and analytical methods. The current design guidelines in the United Kingdom are based on an empirical method, but since they were issued in 1975, several new analytical methods have been proposed. These methods are discussed, and recommendations for an update suitable for United Kingdom conditions are made

A critique of avian CHD-based molecular sexing protocols illustrated by a Z-chromosome polymorphism detected in auklets

The sexes of non-ratite birds can be determined routinely by PCR amplification of the CHD-Z and CHD-W genes. CHD -based molecular sexing of four species of auklets revealed the presence of a polymorphism in the Z chromosome. No deviation from a 1:1 sex ratio was observed among the chicks, though the analyses were of limited power. Polymorphism in the CHD-Z gene has not been reported previously in any bird, but if undetected it could lead to the incorrect assignment of sex. We discuss the potential difficulties caused by a polymorphism such as that identified in auklets and the merits of alternative CHD -based sexing protocols and primers

Efficient and automatic methods for flexible regression on spatiotemporal data, with applications to groundwater monitoring

Fitting statistical models to spatiotemporal data requires finding the right balance between imposing smoothness and following the data. In the context of P-splines, we propose a Bayesian framework for choosing the smoothing parameter which allows the construction of fully-automatic data-driven methods for fitting flexible models to spatiotemporal data. An implementation, which is highly computationally efficient and which exploits the sparsity of the design and penalty matrices, is proposed. The findings are illustrated using a simulation study and two examples, all concerned with the modelling of contaminants in groundwater. This suggests that the proposed strategy is more stable that competing methods based on the use of criteria such as GCV and AIC

Role of microalgae in conditioning water in penaeid larval culture

Microalgae play an important role in conditioning water quality for penaeid larval culture. Recently it has been demonstrated that a modification of the green water larval culture system (Ling, 1969) for Macrobrachium allows the production of post larvae without any water change, despite extensive use of artificial feeds (Ang and Cheah, 1986). Increase of toxic metabolites such as ammonia and nitride are also common in penaeid larval culture, especially where excessive amounts of artifial feeds are employed. Present work examines the use of six marine microalgae at four cell concentrations as a "biological filter" system, to control and detoxify levels of ammonia and nitrite in P. monodon larval culture water whilst using artificial diet. Preliminary results indicate that amongst the six algal species tested, C. japonica at 1000 cell μlˉ¹ was most effective in reducing accumulated toxic metabolites from an unchanged culture water environment

An Experimental Survey of the Cathodic Activation of Metals Including Mg, Sc, Gd, La, Al, Sn, Pb, and Ge in Dilute Chloride Solutions of Varying pH

The kinetics of the hydrogen evolution reaction (HER) have been reported to increase upon pure magnesium (Mg) surfaces, following prior anodic polarisation or corrosion. This phenomenon is termed anodically induced âÂÂcathodic activationâÂÂ, which is not necessarily an elementary concept. The tendencies of other metals to exhibit cathodic activation has not been systematically explored in the past. In this study, an experimental survey of cathodic activation was conducted for different metals on the basis of understanding the origin of the cathodic activation phenomenon on Mg; including the metals Sc, Gd, La, Al, Sn, Pb and Ge, in 0.1 M NaCl with pH ranging from 3-11. Sc, Gd, La and Mg showed cathodic activation in solutions of various pH, whereas Al showed cathodic activation only in an acidic solution. Sn, Pb and Ge did not show significant cathodic activation across the pH range tested. It is proposed on the basis of the results herein, metals that tend to directly react with water to form hydroxides in aqueous electrolytes have a higher tendency to demonstrate cathodic activation

Anderson transition and thermal effects on electron states in amorphous silicon

I discuss the properties of electron states in amorphous Si based on large scale calculations with realistic several thousand atom models. A relatively simple model for the localized to extended (Anderson) transition is reviewed. Then, the effect of thermal disorder on localized electron states is considered. It is found that under readily accessible conditions, localized (midgap or band tail) states and their conjugate energies may fluctuate dramatically. The possible importance of non-adiabatic atomic dynamics to doped or photo-excited systems is briefly discussed.Comment: Was presented at ICAMS18, Snowbird UT, August 1999. Submitted to J. of Non-Cryst. Solid

Towards large scale microwave treatment of ores: Part 1 – Basis of design, construction and commissioning

Despite over thirty years of work, microwave pre-treatment processes for beneficiation of ores have not progressed much further than laboratory testing. In this paper we present a scaleable pilot-scale system for the microwave treatment of ores capable of operating at throughputs of up to 150tph. This has been achieved by confining the electric field produced from two 100kW generators operating at 896MHz in a gravity fed vertical flow system using circular choking structures yielding power densities of at least 6x108 W/m3 in the heated mineral phases. Measured S11 scattering parameters for a quartzite ore (-3.69±0.4dB) in the as-built applicator correlated well with the simulation (-3.25dB), thereby validating our design approach. We then show that by fully integrating the applicator with a materials handling system based on the concept of mass flow, we achieve a reliable, continuous process. The system was used to treat a range of porphyry copper ores

Probing e-e interactions in a periodic array of GaAs quantum wires

We present the results of non-linear tunnelling spectroscopy between an array of independent quantum wires and an adjacent two-dimensional electron gas (2DEG) in a double-quantum-well structure. The two layers are separately contacted using a surface-gate scheme, and the wires are all very regular, with dimensions chosen carefully so that there is minimal modulation of the 2DEG by the gates defining the wires. We have mapped the dispersion spectrum of the 1D wires down to the depletion of the last 1D subband by measuring the conductance \emph{G} as a function of the in-plane magnetic field \emph{B}, the interlayer bias $V_{\rm dc}$ and the wire gate voltage. There is a strong suppression of tunnelling at zero bias, with temperature and dc-bias dependences consistent with power laws, as expected for a Tomonaga-Luttinger Liquid caused by electron-electron interactions in the wires. In addition, the current peaks fit the free-electron model quite well, but with just one 1D subband there is extra structure that may indicate interactions.Comment: 3 pages, 3 figures; formatting correcte