An x ray photoelectron spectroscopy study of Au(x)In(y) alloys

Four gold-indium alloys were studied by x ray photoelectron spectroscopy. The binding energies and intensity ratios of the Au 4f7/2 and In 3d5/2 core levels were determined for the bulk alloy compositions of Au(10 percent In), Au3In, AuIn, and AuIn2. These values were determined for the native oxides on the materials, for the surfaces prepared by ion bombardment to remove the oxide and for surfaces scraped in-situ with a ceramic tool to expose the bulk composition. These results furnish calibration values that allow determination of the composition of thin films of this alloy system. In addition the binding energies add to the data base for understanding the effect of alloying on core level binding energies. As an illustration, these results are used to determine the composition of a series of alloy films formed by incongruent evaporation of an alloy charge

Providing adhesion for a miniture mobile intra-abdominal device based on biomimetic principles

This paper investigates the surface adhesion characteristics required for a miniature mobile device to move around the abdominal cavity. Such a device must be capable of adhering to the tissue lining and move freely across the upper surface of the insufflated abdomen. Accordingly, the potential of utilising bioinspired solutions to facilitate wet adhesion is assessed

Swimming in Granular Media

We study a simple model of periodic contraction and extension of large intruders in a granular bed to understand the mechanism for swimming in an otherwise solid media. Using an event-driven simulation, we find optimal conditions that idealized swimmers must use to critically fluidize a sand bed so that it is rigid enough to support a load when needed, but fluid enough to permit motion with minimal resistance. Swimmers - or other intruders - that agitate the bed too rapidly produce large voids that prevent traction from being achieved, while swimmers that move too slowly cannot travel before the bed re-solidifies around them i.e., the swimmers locally probe the fundamental time-scale in a granular packing

Football 4 Peace versus (v) Homophobia: A critical exploration of the links between theory, practice and intervention

In this chapter, we draw on our different past trajectories to explore the links between theories of sexualities and genders, and anti-homophobic, anti-transphobic and anti-biphobic intervention within UK University footballing contexts. Our critical reflections include over a decade of involvement with scholarship and campaigning surrounding gender and sexuality in football (Caudwell) and significant project development of the Football 4 Peace International reconciliation initiative (Spacey). We seek to plot the ways scholarship, especially theories of gender and sexualities, informs grassroots praxis. More specifically, we focus on the idea of making a difference when it comes to social divisions and inequalities vis-à-vis sexual orientation and gender identity (SOGI). During our discussions we draw from a range of research materials, including the voices of young people and students to demonstrate the ways participation in football can help, as well as hinder, anti-discriminatory policy and practice at the level of the locale

BPS solitons in Lifshitz field theories

Lorentz-invariant scalar field theories in d+1 dimensions with second-order derivative terms are unable to support static soliton solutions that are both finite in energy and stable for d>2, a result known as Derrick's theorem. Lifshitz theories, which introduce higher-order spatial derivatives, need not obey Derrick's theorem. We construct stable, finite-energy, static soliton solutions in Lifshitz scalar field theories in 3+1 dimensions with dynamical critical exponent z=2. We exhibit three generic types: non-topological point defects, topological point defects, and topological strings. We focus mainly on Lifshitz theories that are defined through a superpotential and admit BPS solutions. These kinds of theories are the bosonic sectors of supersymmetric theories derived from the stochastic dynamics of a scalar field theory in one higher dimension. If nature obeys a Lifshitz field theory in the ultraviolet, then the novel topological defects discussed here may exist as relics from the early universe. Their discovery would prove that standard field theory breaks down at short distance scales.Comment: 14 pages, 4 figures; v2: references added and the x-axis scale of each figure has been change

How Can Micro-Level Household Information Make a Difference for Agricultural Policy Making: Selected Examples from the KAMPAP Survey of Smallholder Agriculture and Non Farm Activities for Selected Districts in Kenya

Agriculture forms the foundation of Kenya’s economy. However, the information base on agriculture % including basic indicators on farmers’ input, production, and marketing behavior, household food consumption patterns, etc. % is weak and largely outdated. Agricultural policy is largely made on the basis of conventional wisdom about the way things work. In a dynamic, evolving economy, long-standing perceptions may become increasingly inconsistent with current reality, particularly when the system has been exposed to dramatic changes such as structural adjustment, market liberalization, and the advent of new technology. In such a setting, entrenched perceptions about the way farmers, traders and consumers actually behave may lead to unintended and even counterproductive government policy. This paper aims to demonstrate how monitoring the rural economy through timely, periodic and reasonably representative household surveys can inform debate on existing and emerging policy issues.kenya, agricultural policy, food security, household, Agricultural and Food Policy, Food Security and Poverty, q12,

Detection of carbon monoxide in the high-resolution day-side spectrum of the exoplanet HD 189733b

[Abridged] After many attempts over more than a decade, high-resolution spectroscopy has recently delivered its first detections of molecular absorption in exoplanet atmospheres, both in transmission and thermal emission spectra. Targeting the combined signal from individual lines in molecular bands, these measurements use variations in the planet radial velocity to disentangle the planet signal from telluric and stellar contaminants. In this paper we apply high resolution spectroscopy to probe molecular absorption in the day-side spectrum of the bright transiting hot Jupiter HD 189733b. We observed HD 189733b with the CRIRES high-resolution near-infrared spectograph on the Very Large Telescope during three nights. We detect a 5-sigma absorption signal from CO at a contrast level of ~4.5e-4 with respect to the stellar continuum, revealing the planet orbital radial velocity at 154+4/-3 km s-1. This allows us to solve for the planet and stellar mass in a similar way as for stellar eclipsing binaries, resulting in Ms= 0.846+0.068/-0.049 Msun and Mp= 1.162+0.058/-0.039 MJup. No significant absorption is detected from H2O, CO2 or CH4 and we determined upper limits on their line contrasts here. The detection of CO in the day-side spectrum of HD 189733b can be made consistent with the haze layer proposed to explain the optical to near-infrared transmission spectrum if the layer is optically thin at the normal incidence angles probed by our observations, or if the CO abundance is high enough for the CO absorption to originate from above the haze. Our non-detection of CO2 at 2.0 micron is not inconsistent with the deep CO2 absorption from low resolution NICMOS secondary eclipse data in the same wavelength range. If genuine, the absorption would be so strong that it blanks out any planet light completely in this wavelength range, leaving no high-resolution signal to be measured.Comment: A&A, accepted for publication. Fig.1 reduced in qualit

Library

This history for the Library was collected to commemorate DMACC\u27s 50th anniversary celebration during the 2015-16 academic year