Practical application of three beam diffraction experiments

The experimental setup for the measurement of triplet phases by means of three beam interference experiments is discussed. Attention is drawn to the influence of crystal quality, size of the unit cell, different radiation sources and diffractomcter design. Further on, the application of the three beam method to determine the absolute structure of non-centrosymmetric organic light atom structures is discussed. Also first experiments to exploit experimental phase information in a structure solution process are presented

Multi-electron-recombination rates estimated within dense plasmas

We investigate the rates for multielectron recombination within a dense plasma environment in local thermodynamic equilibrium (LTE). We find that these multielectron recombination rates can be high within dense plasmas, and they should be treated in the simulations of the plasmas created by intense radiation, in particular for plasmas created by intense VUV radiation from free-electron-laser (FEL) or for modelling the inertial confinement fusion (ICF) plasmas

Impulse Evaluation by a Force Transmitting Device in a Blast Environment

An alternative to traditional momentum pendulum and pressure gauges is considered to resolve an improved temporal response to blast and fragmentation, with a protected gauge design. An alternative design based on the use of strain gauges is suggested. A gas gun fitted with a diverging nozzle has been used to validate a version of the system. Numerical analysis has been performed to explore and assess the accuracy of the experimental validation process and indicates an appropriate time range for the validation data. The test and simulation results demonstrate the potential of this device for measurement of blast and fragmentation effects

Professionalism in the Information and Communication Technology Industry

Professionalism is arguably more important in some occupations than in others. It is vital in some because of the life and death decisions that must be made, for example in medicine. In others the rapidly changing nature of the occupation makes efficient regulation difficult and so the professional behaviour of the practitioners is central to the good functioning of that occupation. The core idea behind this book is that Information and Communication Technology (ICT) is changing so quickly that professional behaviour of its practitioners is vital because regulation will always lag behind

Online Communities in Saudi Arabia: an ethnographic study

This paper presents part of a research project about online communities in Saudi Arabia. The paper will address one of the research sub-questions, that is: What are the key features of participation in online communities in Saudi Arabia? The results presented in this paper are drawn from one of the techniques of data collection used in this research, that is, silent observation, which was conducted over a one-year period. In addition, the paper will discuss briefly the research design, including the research procedures. In its final section, some of the findings from this part of the project are presented

Impact of ultrafast electronic damage in single particle x-ray imaging experiments

In single particle coherent x-ray diffraction imaging experiments, performed at x-ray free-electron lasers (XFELs), samples are exposed to intense x-ray pulses to obtain single-shot diffraction patterns. The high intensity induces electronic dynamics on the femtosecond time scale in the system, which can reduce the contrast of the obtained diffraction patterns and adds an isotropic background. We quantify the degradation of the diffraction pattern from ultrafast electronic damage by performing simulations on a biological sample exposed to x-ray pulses with different parameters. We find that the contrast is substantially reduced and the background is considerably strong only if almost all electrons are removed from their parent atoms. This happens at fluences of at least one order of magnitude larger than provided at currently available XFEL sources.Comment: 15 pages, 3 figures submitted to PR