Analytical and Numerical Predictions of Short Pulsed Elastic Waves on a Half-Space

The numerical modeling of ultrasonic wave propagation in elastic solids is particularly attractive for NDT applications because of the relative ease with which the boundaries of realistic defect shapes and testing geometries can be handled. A two-dimensional explicit finite element code [1] has been developed for this purpose

Modelling survival and connectivity of Mnemiopsis leidyi in the south-western North Sea and Scheldt estuaries

Three different models were applied to study the reproduction, survival and dispersal of Mnemiopsis leidyi in the Scheldt estuaries and the southern North Sea: a high-resolution particle tracking model with passive particles, a low-resolution particle tracking model with a reproduction model coupled to a biogeochemical model, and a dynamic energy budget (DEB) model. The results of the models, each with its strengths and weaknesses, suggest the following conceptual situation: (i) the estuaries possess enough retention capability to keep an overwintering population, and enough exchange with coastal waters of the North Sea to seed offshore populations; (ii) M. leidyi can survive in the North Sea, and be transported over considerable distances, thus facilitating connectivity between coastal embayments; (iii) under current climatic conditions, M. leidyi may not be able to reproduce in large numbers in coastal and offshore waters of the North Sea, but this may change with global warming; however, this result is subject to substantial uncertainty. Further quantitative observational work is needed on the effects of temperature, salinity and food availability on reproduction and on mortality at different life stages to improve models such as used here

Surface Wave Modes on Spherical Cavities Excited by Incident Ultrasound

It has been shown both experimentally and theoretically1 that ultrasonic waves propagate circumferentially around the surface of cavities in an elastic medium, besides being reflected from its “flash points”. Surface wave returns were seen to decisively influence the time structure of the echo return from incident ultrasonic pulses. Nagase2 has solved a characteristic equation applicable to the spherical cavity problem, from which it could be shown3 that the surface of a spherical cavity supports a Rayleigh-type and two (P and S) Franz-type surface waves, of known speeds and dispersions. On the other hand, the complex eigenfrequencies of cavities were recently obtained numerically4. We have used these numerical results in order to satisfy Nagase’s solutions, presented in the form of propagation constants of the surface waves as series of fractional powers of the frequency, and have obtained in this way a mode number assignment for all the complex eigenfrequencies. Using this, we calculate dispersion curves for the Rayleigh, P and S- type surface wave phase velocities; their knowledge will permit an accurate interpretation of ultrasonic scattering experiments1, which previously could be analyzed in a qualitative way only

The main features of issue and circulation of exchange bonds in the Russian Federation

The main features of stock exchange bonds were considered in the article, as well as the difference between stock exchange bonds and classical bonds. Two new types which appeared in the Russian federation in 2015-2016, such as single-day stock exchange bonds, and bonds issued within programs of exchange bonds. As the result, a conclusion was drawn on the future development of stock exchange bonds in Russian financial markets

Commentary and Worked Examples to EN 1993-1-10 "Material Toughness and Through Thickness Properties" and Other Toughness Oriented Rules in EN 1993

This commentary gives explanations and worked examples to the design rules in Eurocode 3 that are influenced by the strength and toughness properties of the structural steels used. It is a commentary and background document to EN 1993-1-10 "Material toughness and through thickness properties" and its extension in EN 1993-1-12 "Design rules for high-strength steels", where toughness properties are explicitly addressed. It however provides also background to other parts of EN 1993, e.g. to EN 1993-1-1 "Design of steel structures - Basic rules and rules for buildings", where the design rules are related only to strength properties as the yield strength and the tensile strength without explicitly mentioning the role of toughness that is hidden behind the resistance formulae. Finally it gives some comments to chapter 6 of EN 1998-1: "Design of structures for earthquake resistance - Part 1: General rules, seismic actions and rules for buildings".JRC.G.5-European laboratory for structural assessmen

Epinephrine auto-injector prescriptions to food-allergic patients in primary care in The Netherlands

BACKGROUND: The knowledge of general practitioner(s) (GPs) regarding food allergy and anaphylaxis and practices in the prescription of epinephrine auto-injector(s) (EAIs) among GPs has previously only been studied using questionnaires and hypothetical cases. Therefore, there are currently no data as to whether or not GPs prescribe EAIs to high risk food-allergic patients presenting to primary care practices. The aim of this study was therefore to describe and evaluate practice in EAI prescription by GPs to food-allergic patients in The Netherlands. METHODS: Patients aged 12–23 years who consulted their GP for allergic symptoms were identified in a primary care database. Patients were classified as probably or unlikely to be food-allergic. A risk factor assessment was done to identify probably food-allergic patients at high risk for anaphylaxis to assess the need for an EAI. RESULTS: One hundred forty-eight out of 1015 patients consulted their GP for allergic symptoms due to food. Eighty patients were excluded from analysis because of incomplete records. Thirty-four patients were classified as probably food-allergic. Twenty-seven of them were considered high risk patients and candidates for an EAI. Importantly, only 10 of them had actually been prescribed an EAI by their GP. CONCLUSIONS: This study shows that high risk food-allergic patients that visit their GPs are often not prescribed an EAI. Thus, previously identified low rates of EAI ownership may be partly due to GPs not prescribing this medication to patients for whom it would be appropriate to do so. These data suggest that there is a need for improvement of the quality of care for high risk food-allergic patients in primary care

Workgroup Report: Biomonitoring Study Design, Interpretation, and Communication—Lessons Learned and Path Forward

Human biomonitoring investigations have provided data on a wide array of chemicals in blood and urine and in other tissues and fluids such as hair and human milk. These data have prompted questions such as a) What is the relationship between levels of environmental chemicals in humans and external exposures? b) What is the baseline or “background” level against which individual levels should be compared? and c) How can internal levels be used to draw conclusions about individual and/or population health? An interdisciplinary panel was convened for a 1-day workshop in November 2004 with the charge of focusing on three specific aspects of biomonitoring: characteristics of scientifically robust biomonitoring studies, interpretation of human biomonitoring data for potential risks to human health, and communication of results, uncertainties, and limitations of biomonitoring studies. In this report we describe the recommendations of the panel