Angular Distribution of Bremsstrahlung Produced by 10-keV and 20-keV Electrons Incident on a Thick Au Target

The relative intensities of the thick-target bremsstrahlung produced by 10-keV and 20-keV electrons incident on Au at forward angles ranging from 0 degrees to 25 degrees are compared. Following corrections for photon absorption within the target, the detected radiation appears to be distributed anisotropically only for photon energies, k, that are approximately equal to the initial energy of the incident electrons, E. The results are compared to the theoretical angular distributions of Kissel et al. [At. Data Nucl. Data Tables 28, 381 (1983)]. The comparison suggests that when k/E is approximately equal to 1, the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the theoretical angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets.Comment: The following article has been accepted by AIP Conference Proceedings (Vol. 1525). After it is published, it will be found at http://proceedings.aip.org

International development in transition

This is the pre-peer reviewed version of the following article: HARMAN, S. and WILLIAMS, D. (2014), International development in transition. International Affairs, 90: 925–941. doi: 10.1111/1468-2346.12148, which has been published in final form at http://dx.doi.org/10.1111/1468-2346.12148International development is in a period of transition. While the outcome of this is still unclear, this article argues that there are at least four areas in which the project of international development is changing. First, there is a debate, especially within the World Bank, about development strategy and how we think about development, particularly in terms of the balance between states and markets. This is evident in the debate over state failure and the new structural economics. Second, there is increasing evidence of a shift in lending, away from projects of 'small' human development, perhaps best encapsulated by the United Nations Millennium Development Goals, towards more transformative 'big' development projects such as infrastructure. Third, 'non-traditional' aid donors and new forms of private philanthropy are playing a more significant role in development financing and this, in turn, offers developing countries a new range of choices about what kinds of development assistance they receive. Fourth, aid relations are changing as a result of the renewed agency of developing states, particularly in sub-Saharan Africa, and shifts towards increased South-South cooperation are growing as evidenced by increased funding from regional development banks and increased trade flows. The article reviews these changes and suggests a series of questions and challenges that arise from them for analysts of international development, developing countries and traditional aid donors. © 2014 The Royal Institute of International Affairs

The ‘Lost’ Church of Bix Gibwyn: The Human Bone

Recent research for the Victoria County History (VCH) highlighted the presence of a ‘lost’ medieval church in Bix, a Chilterns parish north-west of Henley-on-Thames. The building, formerly the parish church of Bix Gibwyn, was abandoned in the late sixteenth or seventeenth century and has left no standing remains. Archaeological investigation by the South Oxfordshire Archaeological Group (SOAG) and Reading University has confirmed its location in a close called ‘Old Chapel’ in Bix Bottom, in the north of the parish. The rediscovery of the site – which contains the foundations of a hitherto unknown Romano-British stone building – sheds new light on long-term changes in local communications, settlement, and economic conditions. In the Middle Ages Bix Gibwyn church was a focus of religious and social life for a small rural community in the south Oxfordshire Chilterns. After the Reformation it was neglected, demolished, and finally all but forgotten. Its location has been a matter of speculation for over a hundred years,1 but in 2007–10 its churchyard was identified through a combination of historical research and archaeological fieldwork. Confirmation of the church’s location in the remote Bix Bottom valley provides important evidence about the medieval settlement pattern in Bix, which was very different from the modern one, and offers an opportunity to reassess the development of settlement in the southern Chilterns more generally. The archaeological findings also supply new evidence about Roman activity in the area

Surface heat flux determination: An analytical and experimental study using a single embedded thermocouple

A numerical method by which data from a single embedded thermocouple can be used to predict the transient thermal environment for both high- and low-conductivity materials is described. The results of an investigation performed to verify the method clearly demonstrate that accurate, transient, surface heating conditions can be obtained from a thermocouple l.016 centimeters from the heating surface in a low-conductivity material. Space shuttle orbiter thermal protection system materials having temperature- and pressure-dependent properties, and typical orbiter entry heating conditions were used to verify the accuracy of the analytical procedure. Analytically generated, as well as experimental, data were used to compare predicted and measured surface temperatures

An efficiency study on obtaining the minimum weight of a thermal protection system

Three minimizing techniques are evaluated to determine the most efficient method for minimizing the weight of a thermal protection system and for reducing computer usage time. The methods used (numerical optimization and nonlinear least squares) for solving the minimum-weight problem involving more than one material and more than one constraint are discussed. In addition, the one material and one constraint problem is discussed

An evaluation of errors observed in the measurement of low wind velocities

Measurements of low wind velocities (the absolute value of V sub H is approx. equal to 6 m/s) with a VHF wind profiler can be difficult if ground clutter or other biases in the system dominate in altering the position of the perceived peak in the calculated power spectrum. A variety of methods for ground clutter suppression are used in profiler systems today (Cornish, 1983). An editing method called zero suppression takes the spectral value of selectable number of points (N) on each side of 0 velocity (one point on either side, in this study) and sets them equal to the mean value of the points exterior to the specified N points on either side of 0. Analysis done with the PSU VHF(1) radar, shows that this zero-suppression method can systematically bias horizontal wings V sub H below 6 m/s. With the zero suppression, an artificial increase in absolute wind velocities occurs when the spectral peaks fall within the plus or minus N points of the FFT (personal communication, Strauch, 1985). It was also established that the method artificially decreases the absolute wind velocities inferred from spectral peaks that are outside but near the suppressed region. Comparisons of wind profiles observed with and without zero suppression are given. The range of the biased velocities extends to about plus or minus 6 m/s. Biases have been deduced to be as much as 2 m/s, but more commonly they are on the order of 1.0 m/s

Atomic final-state interactions in tritium decay

We calculate the effect of the Coulomb interaction of the ejected β ray with the bound atomic electron in the β decay of a tritium atom. The excited state probabilities of the residual helium ion are changed by at most 0.17% from the usual sudden approximation

User's guide for CCT2WA (converting CCT's to work-addressable file)

The CCT2WA program, developed to convert the shuttle post-flight computer compatible tape data to a word addressable mass storage file, is described. The use of utility processors that can be used to copy word addressable files from mass storage to mass storage is also described

Effective thermal conductivity determination for low-density insulating materials

That nonlinear least squares can be used to determine effective thermal conductivity was demonstrated, and a method for assessing the relative error associated with these predicted values was provided. The differences between dynamic and static determination of effective thermal conductivity of low-density materials that transfer heat by a combination of conduction, convection, and radiation were discussed