21,539 research outputs found
The Behaviour of Finely Ground Bottom Ash in Portland Cement
The aim of this project was to assess the effects of finely ground MSWI bottom ash in Portland cement. Mortar mixes were prepared with 10% and 40% replacement of cement by ground IBA and then tested with regards to their material composition and engineering behaviour. IBA was found not to be inert, but showed some degree of reactivity. Replacement of cement with IBA was found to have no detrimental effects at low concentrations. This was not the case for 40% replacement, where cement replacement greatly affected strength, creep and drying shrinkage
The Effect of Co-Combusted Biomass-Coal Fly Ash on the Behaviour Portland Cement
This project has investigated the hydration behaviour of pfa-OPC blended cements, comparing conventional pfa with that obtained from co-firing of coal with biomass (palm kernel expeller). Calorimetry, thermal analysis and electron microscopy have been used to investigate the compositions and microstructures of the hydrated pastes. These have been used to explain the materials’ engineering properties (strength development and workability). The results showed that, in the short term, the behaviour of the co-fired material is comparable with that of conventional pfa, there being no discernable differences between the two systems
BVRI photometry of 53 unusual asteroids
We present the results of BVRI photometry and classification of 53 unusual
asteroids, including 35 near-Earth asteroids (NEAs), 6 high
eccentricity/inclination asteroids, and 12 recently-identified asteroid-pair
candidates. Most of these asteroids were not reportedly classified prior to
this work. For the few asteroids that have been previously studied, the results
are generally in rough agreement. In addition, we merge the results from
several photometric/spectroscopic surveys to create a largest-ever sample with
449 spectrally classified NEAs for statistical analysis. We identify a
"transition point" of the relative number of C/X-like and S-like NEAs at
H~18D~1km with confidence level at ~95% or higher. We find that the
C/X-like:S-like ratio for 18<=H<22 is about two times higher than that of H<18
(0.33+/-0.04 versus 0.17+/-0.02), virtually supporting the hypothesis that
smaller NEAs generally have less weathered surface (therefore, less reddish
appearance) caused by younger collision ages.Comment: 18 pages, 9 table
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A multi-parameter criterion for layer formation in a stratified shear flow using sorted buoyancy coordinates
Here, we examine the conditions for layer formation in a stratified shear flow. We reformulate the conditions for amplification of small perturbations to a uniform stratification first proposed by Phillips (Deep Sea Research and Oceanographic Abstracts, vol. 19, 1972, pp. 79–81, Elsevier) and Posmentier (J. Phys. Oceanogr., vol. 7 (2), 1977, pp. 298–300) using the sorted buoyancy coordinates introduced by Nakamura (J. Atmos. Sci., vol. 53 (11), 1996, pp. 1524–1537) and Winters & D’Asaro (J. Fluid Mech., vol. 317, 1996, pp. 179–193). We consider the possible dependence of the effective diffusivity on three non-dimensional parameters, the gradient Richardson number, the buoyancy Reynolds number and the Prandtl number, and obtain a simple expression for conditions favourable for layer formation. The new framework is applied to direct numerical simulations of stratified shear flow. We then apply a recent multi-parameter parameterization developed by Salehipour et al. (Geophys. Res. Lett., vol. 43 (7), 2016, pp. 3370–3379), which suggests that layer formation is favoured for large Prandtl numbers and moderate to large values of the gradient Richardson and buoyancy Reynolds numbers.EPSRC Programme Grant EP/K034529/
Anecdotes to the life and times of Sir Richard Owen (1804-1892) in Lancaster
Sir Richard Owen, a Lancastrian, was a prominent biologist, comparative anatomist, geologist, palaeontologist and known for coining the term dinosaur. His expertise in anatomical dissection proved to be one of his biggest assets and aided his career progression at the Royal College of Surgeons and the Zoological Society. Owen's apprenticeship in Lancaster helped him to gain expertise in anatomy and anatomical dissection. The authors aim to provide some novel contextual background to his childhood in Lancaster, his affection for his hometown and his contribution to Lancaster's sanitary reform. The latter aspect of his scientific accomplishments is typically overlooked
Grid-enabled SIMAP utility: Motivation, integration technology and performance results
A biological system comprises large numbers of functionally diverse and frequently multifunctional sets of elements that interact selectively and nonlinearly to produce coherent behaviours. Such a system can be anything from an intracellular biological process (such as a biochemical reaction cycle, gene regulatory network or signal transduction pathway) to a cell, tissue, entire organism, or even an ecological web. Biochemical systems are
responsible for processing environmental signals, inducing the appropriate cellular responses and sequence of
internal events. However, such systems are not fully or even poorly understood. Systems biology is a scientific field that is concerned with the systematic study of biological and biochemical systems in terms of complex interactions rather than their individual molecular components. At the core of systems biology is computational
modelling (also called mathematical modelling), which is the process of constructing and simulating an abstract
model of a biological system for subsequent analysis. This methodology can be used to test hypotheses via insilico experiments, providing predictions that can be tested by in-vitro and in-vivo studies. For example, the ERbB1-4 receptor tyrosine kinases (RTKs) and the signalling pathways they activate, govern most core cellular processes such as cell division, motility and survival (Citri and Yarden, 2006) and are strongly linked to cancer when they malfunction due to mutations etc. An ODE (ordinary differential equation)-based mass action ErbB model has been constructed and analysed by Chen et al. (2009) in order to depict what roles of each protein plays and ascertain to how sets of proteins coordinate with each other to perform distinct physiological functions. The
model comprises 499 species (molecules), 201 parameters and 828 reactions. These in silico experiments can often be computationally very expensive, e.g. when multiple biochemical factors are being considered or a variety of complex networks are being simulated simultaneously. Due to the size and complexity of the models
and the requirement to perform comprehensive experiments it is often necessary to use high-performance computing (HPC) to keep the experimental time within tractable bounds. Based on this as part of an EC funded
cancer research project, we have developed the SIMAP Utility that allows the SImulation modeling of the MAP kinase pathway (http://www.simap-project.org). In this paper we present experiences with Grid-enabling SIMAP using Condor
Experiments on Visual Acuity and the Visibility of Markings on the Ground in Long-duration Earth-Orbital Space Flight
Visual acuity and visibility of markings on ground in long duration earth orbital space fligh
“A Woman ‘in the snow among the Clocks and instruments’”: How Adrienne Rich Reimagined the Lives of Women Astronomers
Through the lens of historiography, this research examines how the experiences of women in astronomy relate more profoundly than differing historical periods might suggest given metaphors in Adrienne Rich’s poem “Planetarium.” Rich’s poem reimagines common obstacles that female astronomers faced throughout their vocation, conjuring from their lives a new narrative for women in science. Rich uses astronomy as a metaphor for her and other women scientists’ experiences as they struggle to tune out competing personal and professional responsibilities and strive to locate the signal representing purpose and discovery. This presentation seeks to contribute a new perspective in science communication by mitigating gender exclusivity in STEM fields and research settings
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