Hyperon-nucleon interactions in effective field theory

We have constructed the leading order hyperon-nucleon potential in a chiral Effective Field Theory approach. The chiral potential consists of one-pseudoscalar-meson exchanges and non-derivative four-baryon contact terms. The hyperon-nucleon interactions are derived using SU(3) symmetry, the nucleon-nucleon interaction is not considered explicitly since it can not be described well with a leading order chiral Effective Field Theory. We solve a regularized Lippmann-Schwinger equation and show that a good description of the available hyperon-nucleon scattering data is possible with five free parameters. The chiral potential can be used as further input for hypernucleus and hypernuclear matter calculations. Preliminary hypertriton calculations yielded the correct hypertriton binding energy.Comment: 6 pages, 6 PostScript figures, invited talk to appear in the proceedings of the "IX International Conference on Hypernuclear and Strange Particle Physics

S=-1,-2 baryon-baryon interactions in chiral effective field theory

We have constructed the leading order strangeness S=-1,-2 baryon-baryon potential in a chiral effective field theory approach. The chiral potential consists of one-pseudoscalar-meson exchanges and non-derivative four-baryon contact terms. The potential, derived using SU(3) symmetry constraints, contains six independent low-energy coefficients. We have solved a regularized Lippmann-Schwinger equation and achieved a good description of the available scattering data. Furthermore a correctly bound hypertriton has been obtained.Comment: 3 pages, 2 PostScript figures, talk to appear in the proceedings of the "International Nuclear Physics Conference (INPC2007), Tokyo, Japan, 3-8 June 2007

Strange two-baryon interactions using chiral effective field theory

We have constructed the leading order strangeness S=-1,-2 baryon-baryon potential in a chiral effective field theory approach. The chiral potential consists of one-pseudoscalar-meson exchanges and non-derivative four-baryon contact terms. The potential, derived using SU(3)_f symmetry constraints, contains six independent low-energy coefficients. We have solved a regularized Lippmann-Schwinger equation and achieved a good description of the available scattering data. Furthermore a correctly bound hypertriton has been obtained.Comment: 3 pages, 2 PostScript figures, talk to appear in the proceedings of the "20th European Conference on Few-Body Problems in Physics (EFB20), Pisa, Italy, 10-14 September 2007

Investigation of the Coupling Paths of a Galvanically Isolated AC/AC Converter

A galvanically isolated three-phase AC/AC converter with a high-frequency AC-link has been analyzed from an EMC point of view. This is a special configuration because of a large number of switches, a high frequency transformer, and a fourwire output. The essential coupling paths are identified.\ud Corresponding suppression remedies are given. The results, before and after measures, have been presented to demonstrate the improvement in EMC.\ud Keywords: AC/AC converter; electromagnetic interference; galvanically isolated\u

Using transfer ratio to evaluate EMC design of adjustable speed drive systems

This paper proposes a way to evaluate the conducted electromagnetic compatibility performance of variable speed drive systems. It is considered that the measured noise level is determined by two factors, the level of the noise source and the conversion efficiency of the propagation path from the source to the measurement equipments. They are corresponding to the two roles played by the converter. On the one hand, a converter provides the noise source and generates the noise current and voltage on the motor side with the cable and the motor. On the other hand, it acts as the propagation path with the DC bus and the rectifier to spread the noise generated on the motor side to the line side. The transfer ratio is defined as the ratio between the CM current on the motor side and the CM current on the line side. It can be used to evaluate the EMC design of a converter because it is independent of the cable and the motor. A simplified model is used to explain this characteristic. It can be measured when the converter is powered off. Verification is carried out by experimental results obtained from a 12-kVA laboratory system.\u

Economic and Health impact of injuries in the Netherlands and Europe

Acute lichamelijke letsels, veroorzaakt door ongevallen vormen een altijd aanwezig en dynamisch volksgezondheidsprobleem. Elk jaar raken alleen al in Nederland ca 1 miljoen mensen zodanig gewond dat zij onderzocht en behandeld moeten worden op de Spoed Eisende Hulp van een ziekenhuis. In dit proefschrift worden de medische kosten en de ziektelast van ongevallen voor Nederland en Europa bestudeerd. Hiermee kunnen ziekten, risicofactoren, en bevolkingsgroepen geïdentificeerd worden met de grootste behoefte aan zorginterventies. In een Europese studie worden de kosten van acht Europese landen vergeleken met elkaar, waarbij grote internationale verschillen zijn waargenomen. Belangrijke veroorzakers van hoge kosten zijn het veel voorkomen van ernstige letsels (Oostenrijk en Griekenland), verschillen in gezondheidszorgsystemen en traumazorg (hoge opnamekans en opnameduur voor Oostenrijk en Noorwegen), en hoge kostprijzen voor de gezondheidszorg (Noorwegen en Denemarken). Mensen ouder dan 65 jaar, in het bijzonder vrouwen, nemen een groot deel (meer dan een derde) van de totale zorgkosten voor hun rekening, met name veroorzaakt door botbreuken (heup- en knie/onderbeen). Jonge kinderen en mannen van middelbare leeftijd zijn ook groepen met relatief hoge medische kosten. Functionele gevolgen zijn gemeten bij een brede populatie ongevalspatiënten die zijn behandeld op de spoedeisende hulp in Nederland, 2½, 5, 9 en 24 maanden na het ongeval. Ongevalspatiënten die voor langere tijd opgenomen zijn geweest (> 7 dagen), ervaren twee jaar na het ongeval nog steeds aanzienlijke gezondheidsbeperkingen. Leeftijd (65+), Geslacht (vrouwen), specifieke letsels (heupfractuur, ruggenmergletsel, schedel-hersenletsel), en de aanwezigheid van andere ziekten (comorbiditeit) geven een verhoogd risico op langdurige gevolgen van een ongeval

Wound healing with honey - a randomised controlled trial

Objectives. To compare honey and IntraSite Gel as woundhealing agents, to record side-effects, gauge patient satisfaction and calculate the  cost-effectiveness of the honey used.Design and setting. A prospective, randomised, double-blind controlled trial was carried out among goldmine workers.Outcome measures. Outcome measures were healing times of shallow  wounds and abrasions; side-effects; patient satisfaction with treatment; and amount of honey and IntraSite Gel used.Results. The mean healing times of shallow wounds treated with honey or  with IntraSite Gel did not differ significantly (p = 0.75, 95% confidence  interval (CI): -5.41; 7.49 days). When adjusted for wound size, the 2.8-day difference in favour of honey was not significant (p == 0.21, 95% CI: -2.41; 8.09). In the case of abrasions there was also no significant  difference (p = 0.83, 95% CI: -4.98; 6.19 days). When adjusted for woundsize, the difference of 0.22 days in favour of IntraSite Gel was not    significant (p = 0.94, 95% CI: -5.72; 6.15.4). Of patients treated with honey, 27% and 10% respectively experienced itching and pain, and 2  experienced burning for a short time after application. Of patients treated with IntraSite Gel, 31% experienced itching. All patients in both treatment groups were either satisfied or extremely satisfied with treatment. The average cost of treatment per patient was R0.49 with honey and R12.03 with with IntraSite Gel.Conclusions. A distinction should be made between shallow wounds and  abrasions when wound healing is being measured. There was no evidence of a real difference between honey and IntraSite Gel as healing agents. Honey is a safe, satisfying and effective healing agent. Natural honey is extremely costeffective

Wound healing with honey - a randomised controlled trial

Objectives. To compare honey and IntraSite Gel as woundhealing agents, to record side-effects, gauge patient satisfaction and calculate the cost-effectiveness of the honey used. Design and setting. A prospective, randomised, double-blind controlled trial was carried out among goldmine workers. Outcome measures. Outcome measures were healing times of shallow wounds and abrasions; side-effects; patient satisfaction with treatment; and amount of honey and IntraSite Gel used. Results. The mean healing times of shallow wounds treated with honey or with IntraSite Gel did not differ significantly (p = 0.75, 95% confidence interval (CI): -5.41; 7.49 days). When adjusted for wound size, the 2.8-day difference in favour of honey was not significant (p = 0.21, 95% CI: -2.41; 8.09). In the case of abrasions there was also no significant difference (p = 0.83, 95% CI: -4.98; 6.19 days). When adjusted for wound size, the difference of 0.22 days in favour of IntraSite Gel was not significant (p = 0.94, 95% CI: -5.72; 6.15.4). Of patients treated with honey, 27% and 10% respectively experienced itching and pain, and 2 experienced burning for a short time after application. Of patients treated with IntraSite Gel, 31% experienced itching. All patients in both treatment groups were either satisfied or extremely satisfied with treatment. The average cost of treatment per patient was R0.49 with honey and R12.03 with with IntraSite Gel. Conclusions. A distinction should be made between shallow wounds and abrasions when wound healing is being measured. There was no evidence of a real difference between honey and IntraSite Gel as healing agents. Honey is a safe, satisfying and effective healing agent. Natural honey is extremely costeffective. South African Medical Journal Vol. 96(9) 2006: 831-83

Chapter Tidal Turbine Generators

Recently, tidal stream turbines have become a preferable mode of harvesting tidal energy. The main issue for low utilization of tidal energy is the high levelized cost of energy (LCoE) from tidal stream turbines. A major reason for this is the high operation and maintenance costs for submerged installations. A possible way of minimizing the LCoE and improving the availability is to use a flooded (or a wetgap) generator rather than a conventional airgap generator. Inside flooded generators, the gap between the stator and rotor is filled with the seawater. This architecture has the potential to improve cooling and reduce reliance on ancillary systems (e.g., bilge system), thereby improving reliability. The chapter begins with a brief description of the generator systems used in current tidal stream turbines. The focus of the chapter is, however, to give a basic insight into the design aspects of the flooded generators, and compares it with the currently used sealed airgap generators in tidal turbine systems