sur la médiatisation des élections Il s'est ouverte le 16 septembre 2011 à Matadi dans le Bas-Congo une formation sur la médiatisation des questions électorales,...
L'invention concerne un procede de triage de cristaux irradies. Ce procede non destructeur comporte l'irradiation des cristaux par un rayonnement ionisant pendant une duree et avec une intensite telles qu'il se forme des centres colores distinctifs dans les matieres contenant des ions aluminium. Les cristaux colores qui correspondent en teinte et en profondeur de couleur a des teneurs en aluminium en dehors de la teneur desiree peuvent etre separes. On peut isoler ainsi des matieres de quartz, de verre, de silicates exemptes d'aluminium dans un melange, ou bien on peut choisir des fractions de ces matieres, chacune contenant une teneur uniforme en aluminium.
RESUME: Cet article propose une tude du r le croissant que joue l valuation dans la gouvernance des services domicile en Europe. L introduction de quasi march s dans plusieurs pays europ ens va de pair avec un processus d autonomisation de la fonction d valuation qui devient un v ritable outil de r gulation de la concurrence. Une analyse compar e des situations en Belgique, France et Royaume Uni, tant de la demande que de l offre de services, met en vidence les tensions r currentes dans les objectifs de l valuation (qualit des services, ma trise des budgets sociaux, cr ation d emploi), la faible prise en compte de la qualit de l emploi ainsi que les limites des dispositifs standardis s d valuation au regard de la rh torique du libre choix de l usager (consommateur).
After a presentation of methods and tools for the basic and extensive characterization of polluted sites and the study of evolution and transfer of current organic pollutants in the ground, the example of the rehabilitation of an old Rhone-Poulenc site (at Chauny, France) polluted with metals and arsenic, is described: soil and aquifer diagnosis, risk analysis and determination of migration schemes
The results make appear that the cesium 137 would be eliminated less quick than what the ICRP considered for its models. Pectin would accelerate the cesium elimination but less quick than what is announced by its promotors. Politically speaking, the pectin is ignored by the officials of medicine and radiation protection at the pretext that its efficiency is not proved but no study is made. (N.C.)
This work gives a global view of legislations in which are included metals chemical states, briefly recalls the conditions to be respected for the CRM (Certified Reference Materials), and describes the results of some current plans for the Norms, Measures and Tests program. (O.M.) 23 refs.
... Producers and their Impacts on Women in Central Java, IndonesiaActions basées sur des scénarios visant à élever ... impact sur les femmes dans le centre de Java, en IndonésieInvestigación-acción basada en...
The in-situ observation of dendritic growth in lithium/polymer electrolyte-LiTFSI/lithium battery cells shows that dendrites grow up with about the same rate as anion migration. Memory effects have been evidenced in cycling experiments and limit the dendrites length. An overall movement of the electrolyte due to variations of electrolyte concentration in the vicinity of the electrodes has been observed too. (J.S.) 13 refs.
CYRANO3 is the new EDF thermomechanical code developed to evaluate the overall fuel rod behavior under irradiation. In that context, this paper presents the phenomena to be simulated and the correlations adopted for modelling purposes. The empirical models presented are taken from the CYRANO2 code and a compilation of the relevant literature. The present revision corrects and supplements version B on the basis of its use during the software coding phase from January 1991 to May 1993. (authors). figs., tabs., 120 refs.
The European gas market is continuing to expand due to increased industrial, domestic and power generation demand. As a result of this demand, and the trend toward liberalization of the market, the need for storage of gas is also increasing. One key segment of the large scale storage of gas is underground storage, either in partially depleted gas or oil fields, naturally occurring caverns, aquifers and salt cavities. In most cases the gas produced after storage requires conditioning to meet the water of hydrocarbon dew point specification of the gas transmission system. For that reason export gas from storage will require gas conditioning in order to meet pipeline specifications. Adsorption as a feasible and reliable process will be presented in detail and especially in regards to hydrocarbon dew-pointing compared with other process options. (author)
We have studied freshly prepared lysozyme solutions in heavy water for two NaCl concentrations as a function of temperature. Lysozyme solubilities in this solvent are determined by static light scattering. By small angle neutron scattering, we evidence that interactions between lysozyme molecules are characterized by a second virial coefficient A{sub 2} whether the solution is under-saturated or supersaturated. From the variation of A{sub 2} as a function of temperature we have evaluated the enthalpy corresponding to the interaction between lysozyme molecules. We show that the interactions between protein molecules are higher in heavy water than in light water. (authors). 13 refs., 3 figs.
Radon ({sup 222}Rn) is a naturally occurring radioactive gas and can be used as a tracer in hydrogeologic studies. Radon concentration measurements have been achieved in ground-air and in groundwater by means of nuclear track detectors to estimate long-term variations. Continuous measurements have been conducted using an electronic automatic probe, to evaluate short-term variations. The results obtained from bore-holes show a good correlation between the aquifer`s structural characteristics and the radon concentrations. The continuous measurements specify rainfall influence. (author). 10 refs., 7 figs., 2 tabs.
ResumeLa convergence des solutions faibles du systeme de Navier-Stokes-Fourier-Poisson compressible avec un terme de frottement est etudiee dans la limite dun frottement infini, la loi de pression incluant, comme cas particulier, celle correspondant aux particules de Fermi-Dirac. La limite se trouve etre une solution faible dun systeme de Smoluchowski-Poisson non isotherme, la temperature ne dependant que de la variable temporelle et etant determinee par la conservation de lenergie totale.
More and more reforms in public administrations are being conducted that are based on the principles and instruments of ''new public management''. They have set off protest and collective actions by several professional groups in various sectors (health, education, justice, social work, research...), whence questions about the future of professional groups in public services, in particular about their autonomy, which these reforms threaten. The opposition between this new public management and certain professional groups, is not the final explanation to draw from an analysis of this situation. Should these changes be seen as the decline of professional groups and of their autonomy, as a mutation of professional models, an overhaul of professionalism, etc.? These questions, which current ev...
The aim of this economic study is the wording of a synthetic document for the public information in the framework of the 98/30/CE european directive transposition to the gas internal market. It is writing in four main chapters, one for each country concerned: the Germany, the Spain, the Netherlands and the United Kingdom. Each one presents the historical context, the actors of the natural gas industry and the main provisions. (A.L.B.)
Passive films, formed on annealed and cold worked AISI 304 stainless steel in hot chloride media, were examined using polarization resistance and impedance measurements. The obtained results show the influence of cold work on film conductivity, which can be correlated to conditions of susceptibility to stress corrosion cracking. Capacitance measurements, using the Mott-Schottky approach, revealed that a change from n to p type semi-conductivity is associated to susceptible conditions with an increase in the doping density estimated for cold worked samples in the presence of chloride. It is assumed that p-type semi-conductivity of the passive film together with the position of the flat band potential has a strong influence on the dissolution processes at the corrosion potential. Based on this analysis the influence of plastic deformation, at the dislocation scale, is discussed. (authors)
Freezing and thaw have an effect on soils, and the effect of the freeze-thaw cycle on soil covers used in the control of acid mine drainage was discussed in this poster presentation. The purpose of soil covers in cases involving acid mine drainage (AMD) is to reduce the exposure of tailings to oxygen which cause AMD. The effect of this freezing-thaw cycle on soft materials used in soil covers with capillary effect was studied. Some laboratory experiments were conducted to evaluate the properties of the moisture retention layer. The preliminary results were presented. The results indicated that the freeze-thaw cycle might affect the performance of soil covers in the long term, depending on the type of materials selected. Further research is undergoing. 26 figs.
Steam generator tubes in nuclear power plants are periodically checked by means of eddy current probes. The output of a probe is composed of three types of signals: known events (rolling zone, support plates, U-bend part), noise (mainly metallurgical noise) and possible flaws. The latter are random transients, both in arrival time and in shape: they have to be detected and then estimated, before to be fed to the high level stages of a diagnostics system. The objective of the study presented is to develop a semi-automatic system, which could manage and process more than 1 M-bytes of data per tube and provide an operator with reliable diagnostics proposals within a few minutes. This can be achieved only by cooperation of several digital signal processing techniques: detection, segmentation, estimation, noise subtraction, adaptive filtering, modelization, pattern recognition. The paper describes some of these items.
Steam generator tubes in nuclear power plants are periodically checked by means of eddy current probes. The output of a probe is composed of three types of signals: known events (rolling zone, support plates, U-bend part), noise (mainly metallurgical noise) and possible flaws. The latter are random transients, both in arrival time and in shape: they have to be detected and then estimated, before to be fed to the high level stages of a diagnostic system. The objective of the study presented is to develop a semi-automatic system, which could manage and process more than 1 M-bytes of data per tube and provide an operator with reliable diagnostics proposals within a few minutes. This can be achieved only by cooperation of several digital signal processing techniques: detection, segmentation, estimation, noise subtraction, adaptive filtering, modelization, pattern recognition. The paper describes some of these items.
The sedimentary geometry is determined by several types of stratigraphic surfaces: transgressive surfaces (TS), maximum flooding surfaces (MFS) and downward shift surfaces (DS). They are organized hierarchically into major and minor surfaces from the facies stacking-pattern. These surfaces which are observable on well logs and cores structure the sedimentary architecture and are, therefore, the best candidates to form major seismic reflectors. The well (logs and cores) to seismic (surface seismic) passage involves inherently a change of observation scale. That is from a high resolution sequence stratigraphy (metric to pluri-metric) to a sequence stratigraphy s.l. (decametric to pluri-decametric). This passage is composed of two phases. The first phase consists of the validation of density and sonic logs whose product corresponds to the acoustic impedance. The second phase allows for the modelling of the geological cross section of a field in a synthetic seismic ...
Lithium ion batteries use an oxide as a positive electrode and a carbon material as a negative electrode. The performances of carbon electrodes have rapidly evolved during the last years thanks to the substitution of soft carbons of Conoco or MCMB-2510 type by graphites (F-399, MCMB-2528) and then by hard carbons. These high capacity carbons (700 mAh/g) have higher service life and volume capacity than graphites but their irreversible losses are greater (>20%). In this work, materials with similar electrochemical performances are prepared by mechanical crushing. Mechanical crushing allows to obtain a wide range of carbon materials with various morphologies, specific surfaces and levels of disorder. The formation of the passivation film is directly linked with the surface of materials. A reaction scheme of the reversible and irreversible capacities has been defined and has permitted to obtain compounds with reversible capacities of 720 mAh/g (2 lithium for 6 carbon). (J.S.)
This work presents the development of a streak camera 'jitter free' sweep unit synchronized on a femtosecond laser. This application of high voltage photoconductive switches ('High voltage Auston switch') yields subpicosecond resolution for accumulated images on streak camera on a few hundreds micro joule femtosecond laser. Two others applications of these photoconductive switches are studied: - ultrafast optical commutation by a Pockels cell directly driven by a photoconductive switch (rising edge < 100 ps and jitter < 2 ps), - laser pulse energy self-stabilization experimentally proving that driving a Pockels cell by a photoconductive switch can increase the stability of the laser pulse energy from 7 % to 0.7 % rms. Additionally, the application of the acoustic-optical programmable dispersive filter (Dazzler) to the self referenced spectral phase measurement is presented. As these measurements require a linear filter combined with a ...
The aim of this thesis is to study the coherent transport in semiconducting-superconducting junctions. The SnPb-GaAs system has been studied. It has been shown that the behaviour of this junction is controlled by the disordered area induced by the annealing of the connection near the interface. For a few resistant junction, a conductance anomaly under the gap has been observed and has been explained by a mesoscopic effect in the limit of the very high disorders. The conductance of more resistant junctions has only been bound to the properties of the very disordered area of the semiconductor. The part of the electron-electron interactions on the phase coherence length and on the conductance has been studied. The evolving of the correction of the conductance due to interactions in magnetic field has been followed. The effect of the spin degeneration suppression in CdTe and the GaAs sign inversion in Shubnikov de Haas oscillations rate has been observed. At last has been studied the ...
The control of nitrogen oxides (NO{sub x}) emissions will become a major challenge in the forthcoming years, in the domain of automotive industry or industrial burners. Pulsed combustion offers an imaginative solution which does not affect the combustion efficiency. In this paper, the efficiency of this method is demonstrated using the burner of a 20 kW domestic boiler. The actuator is simply installed on the air intake. Two types of actuators have been tested successfully: a loudspeaker and a rotative valve. Both can produce 100 to 1000 Hz frequencies and can lead to a reduction of 20% of NO{sub x} emissions. The feasibility of the concept is also demonstrated on a 840 kW liquid fuel-oil burner. The mechanisms involved during an excitation are explained using the CH{sup *} radical imaging. Results show an important reorganization of the flow and of the flame structure. During each excitation cycle, an annular swirl occurs at the leading edge of the flame catching and develops during ...
Simplifying hypotheses are required when combustion and aerodynamic phenomena are considered simultaneously. In this paper, a turbulent combustion model is proposed, in which the combustion chemistry is reduced to a single reaction. In this way, only two variables are needed to describe the problem and combustion can be characterized by the consumption of one of the two reactive species. In a first step, the instantaneous consumption rate is obtained using the Lagrangian form of the mass fraction equation of the species under consideration, and by considering the equilibrium state only. This state is determined in order to preserve the consistency with results that should be obtained using a complete kinetics scheme. In a second step, the average rate is determined using the instantaneous consumption term and a probabilistic density function. This model was tested on various configurations and in particular on an experimental main chamber and on a reheating chamber. Results indicate ...
The suitability of the turbulent combustion flamelets model in order to predict the index of NO{sub x} production in turbulent flames of hydrogen diffusion is analyzed. In the flamelet approach, the turbulent flame is equivalent to a group of laminar flames submitted to a mechanical stretching which generates a chemical disequilibrium. This effect can be described by the stretching or by the scalar dissipation ratio. A numerical modeling is performed in order to evaluate the advantages of both approaches and to compare the behaviour of the NO{sub x} emission index with the experiments of Chen and Driscoll. This study shows that predictions of NO{sub x} emission indexes have a correct behaviour with respect to the Damkoehler number only when the scalar dissipation ratio is used as a parameter to describe the chemical state outside equilibrium. Predictions of the flamelet models are improving when the Damkoehler number increases. On the other hand, the absolute NO{sub x} concentrations ...
ResumeObjectif determiner dans une etude randomisee l'impact d'un enregistrement continu du glucose sous-cutane pendant 48 heures sur le controle glycemique trois mois plus tard chez des patients presentant un diabete de type 1 (DT1) ou de type 2 (DT2). Methodes Quarante-huit patients avec un mauvais equilibre glycemique (HbA1c : 8-10,5 %) ont beneficie d'un enregistrement continu du glucose sous-cutane pendant 48 heures avec le systeme GlucoDay (A. Menarini Diagnostics) et ont ete randomises en deux groupes : ajustement de traitement en fonction de l'autosurveillance glycemique capillaire (groupe ASG) ou du profil d'enregistrement continu du glucose sous-cutane (groupe CGM). Le dosage d'HbA1c et le port du GlucoDay ont ete renouveles trois mois plus tard. Resultats Trente-quatre patients ...
This study examines some radiation accidents occurred in the past. This information has been systematically assessed to get global lessons. The experience feedback shows that the most of accidents happened in certain conditions. These conditions can be distributed in four categories: 1- perception and vigilance in occupation: accidental exposure happened by lack of vigilance in details and lack of vigilance and perception; 2- procedures: accidental exposure happened following a lack of procedures or control that were not enough complete, not enough documented or not completely implemented; 3- training and understanding: accidental exposures happened because the personnel was not enough qualified and educated, did not get the general training nor the the necessary specialized training; 4- liabilities: accidental exposures happened following lacks and ambiguity in the definition of functions of the personnel and in the hierarchy liabilities. In these precise cases the safety tasks have ...
A model-base expert system is presented for the processing of alarm messages in power networks' control centers. This alarm processor, called GESTAL, generates concise diagnoses identifying the causes(s) of network disturbances and describing the operation of the protection and alarm systems which operate to isolate faulty components. Essentially, the alarm processor is an agenda driven expert system which is composed of a model of the power network's alarm and protection systems as well as several sets of rules. Based on the nextwork model, graph structures are constructed which represent relationships between alarms as they are received. These graph structures are then analysed in order to diagnose the disturbances(s). The alarm processor has been developed using the ART 3.0 programming language in a Symbolics Lisp-machine environment. Background material on expert systems, electric power networks, and alarm processing software is included, as well as a description ...
The study had three objectives: to collect information that explain the impact of the Aube storage center (C.S.A.) on environment and allow to evaluate the consequences for man, secondly, to build a referential for any future inquiry or follow-up, thirdly, to allow to the local commission of information to elaborate an information towards the side residents and local actors that take into account their questions. Trees, waters, sediments, soils, grass, products of gardens and vineyards were the object of sampling, their dosimetry is given in this report. Other dosimetry measures were made along the nuclear site and the results are equally in this report. (N.C.)
When liquids are confined in nano-scopic dimensions, their properties differ from the corresponding bulk liquid, due to their reduced dimensionality and surface effects. Phase transition temperatures and pressures are often shifted from the bulk values and new phases can appear due to the strong interactions of the molecules with the confining walls. We have studied the structural and dynamical properties of aromatic liquids such as benzene, toluene, and ortho-terphenyl confined in nano-porous materials, MCM-41 and SBA-15, synthesized and characterized in our laboratory. A non-trivial dependence of the glass transition temperature, T{sub g}, on the pore size and surface treatment of nano-porous materials is confirmed and interpreted as resulting from a competition between the fluid-wall and fluid-fluid intermolecular interactions. An increase of T{sub g} is observed for small pore sizes and attractive surface while T{sub g} decreases for non attractive surface, whatever the pore size. ...
In front of the risks linked with the increase of the greenhouse gas emissions in the atmosphere, the decision makers must take into consideration first, the scientific advice of climatic change experts, and second, the considerable inertia of the climatic system. Thus, any action implemented so far will have an impact all along the 21. century and later whatever the future human activities. The aim of this memento is to sensibilize the decision makers about the possible consequences of their choice in terms of volume of greenhouse gases and of medium- and long-term evolution: 1 - stakes, role of local decision-makers (greenhouse effect and climatic change, France's international commitment, stakes, liabilities of local decision makers, decentralization laws, local plans of fight against greenhouse effect, public information and dialogue); 2 - urbanism and transports (urban displacements, alternatives to individual cars, collective transportation systems, parking, inter-region ...
Qualitative interpretation of data of different nature and sources, based on segmentation techniques such as discriminant analysis, is useful to characterize and monitor hydrocarbon reservoirs. In order to make this interpretation more reliable, it is necessary to characterize uncertainties attached to data and then, to propagate them in the interpretation work-flow. In this thesis, uncertainties are represented by intervals, because usually, little is known about input data errors. The uncertainty characterization issue is dealt with specifically for each case study. The uncertainty propagation issue is treated by a new technique, based on interval analysis, which consists in extending to intervals various popular approaches (non parametric, quadratic and linear) to discriminant analysis: Firstly, a learning phase allows calibrating an imprecise classifying model on the basis of pre-interpreted data. If the quality of this model is good enough, it is used to interpret the whole set of ...
The growing concern of the population with regards to the problem of atmospheric pollution has induced a change in the role of air quality monitoring networks, especially those monitoring air pollution in large cities which suffer from summer smog. The population is no longer satisfied with real-time measurements but wants to be warmed of high pollutants concentrations in advance. Some countries have been forecasting air pollution, and especially ozone, for a large number of years. Although most of them use statistical models based on the analyses of past conditions which induced high pollution episodes, some predict ozone levels using only their knowledge of the meteorological situation. Nowadays two trends appear regarding ozone forecasting: either very basic statistical methods, such as regression, or more sophisticated ones, such as neural networks. The paper then reviews several behaviours common to most forecasting models: the uncertainly due to the great dependence upon the ...
This study resumes the discovery of an excess of actinium 227 found around by EL4 nuclear reactor actually in dismantling. The search for the origin of this excess revealed a real inquiry of investigation during three years. Because a nuclear reactor existed in this area a particular attention will have concerned this region. The doubt became the line of conduct to find the answer to the human or natural origin of this excess. Finally and against any evidence, it appears that the origin of this phenomenon was natural, consequence of the particular local geology. The detail of the different investigations is given: search of a possible correlation with the composition of elevations constituent of lanes, search (and underlining) of new sites in the surroundings of the Rusquec pond and the Plouenez station, study of the atmospheric deposits under winds of the nuclear power plant and in the east direction, search of a possible relationship with the gaseous effluents of the nuclear power ...
This thesis presents the work achieved to instrument the ATLAS software framework, ATHENA, with a library of tools and utensils for the physics analysis as well as the extraction of the jet energy scale using physics events (in-situ calibration). The software part presents the various components of the ATHENA framework which handles the simulated and reconstructed data flow as well as the different stages of this process, before and during the data taking. The building of a library of tools easing the reconstruction of physics objects, their association with Monte-Carlo particles and their API is then explained. The need for common language and collaboration-wide utensils is emphasised as it allows to share the workload of validating these tools and to get reproducible physics results. The analysis part deals with the implementation of a light jet energy scale calibration algorithm within the C++ framework. This calibration algorithm makes use of W bosons decaying into light jets ...
The 24 papers presented at the conference on Neutralisation des eaux de drainage dans l'environnement minier (NEDEM) (Mine Environment Neutral Drainage (MEND)) 2000 symposium on research on innovative methods to control acid mine drainage, covered eight sessions with both technical and general interest papers. The technical papers covered the topics of acid mine drainage and remediation measures, such as flooding, soil cover with various materials, encapsulation, and others. Other topics discussed included the freeze-thaw cycle and its effect on the performance of soil covers. The environmental impacts of acid mine drainage were also described. Some case studies were included to further illustrate the environmental impacts of acid mine drainage and to demonstrate the effectiveness of remedial actions in specific situations. Most of the cases studied were mines located in Quebec and Northern Ontario, with some in British Columbia. The ...
This document deals with the couplings between the W boson and Z and gamma particles. WWZ and WW{gamma} vertex are predicted by the electroweak theory based on the symmetry group SU(2){sub L}*U(1){sub Y}, their existence is confirmed by the measurement of the production cross-section of W pairs at LEP. The effective values of the couplings are modified by the introduction of standard model particle loops at the vertex level, the impact on the coupling value is assessed to reach 10{sup -3}. These loops can also include beyond-the-standard-model particles, their impact is in the magnitude order of 10{sup -3} for most models. The fully description of these loops requires the values of 14 complex parameters whose measurement will give information about the existence of new particles. Nevertheless the number of events at LEP is not sufficient to measure all the parameters simultaneously. As a consequence the analysis is limited to the 3 most promising parameters: g{sub 1}{sup Z}, ...
The central topic of this work is the study of the properties and the implementation of a Paul trap used for the measurement of the beta-neutrino angular correlation parameter in the decay of {sup 6}He. This coefficient provides a signature of the nature of the interactions involved in the weak interaction. The value of this coefficient can be deduced from the kinematical distribution of the decay events. An electromagnetic trap is used for the trapping of {sup 6}He{sup +} ions in a small volume. This trap has an open geometry that enables the detection in coincidence of the electron and the recoil ion emitted in the beta decay. A dedicated detection set up is used for the measurement of the electron energy, the ion time of flight and the position of the two particles for each event. A general description of the LPCTrap facility and of its performances is presented and shows that this set up is able to fulfill the proposed measurement. Especially, a comparison is ...
Tribological performance of alumina and silicon carbide ceramics as well as of the hardened steel 100Cr6 for reference was studied during reciprocating sliding and cavitation erosion in isooctane as substitute of gasoline and in distilled water. It was the aim to characterize effects of surface finish of the specimens and the liquid media on friction, resistance to sliding wear and cavitation erosion. Sliding wear tests were run on the self-mated ceramics and ceramic/steel pairs under conditions of boundary lubrication using a laboratory tribometer with cylinder-on-plate geometry. Vibratory cavitation erosion tests were conducted according to ASTM G 32-92. High initial surface roughness of coarse ground specimens led to a distinct running-in period during sliding contact with a transition from high to low values of friction coefficient and wear intensity. Incubation time was reduced with increasing surface roughness in the cavitation tests. Depending on the ...
The study presented in this thesis is a contribution toward improving the reliability of Metallized Polypropylene Film (MPPF) capacitors achieved by a better design. A temperature distribution in the roll is assumed with the aim of optimizing its thermal performance. It appears that the heating of long capacitor is higher than that of equivalent flat capacitor subjected to the same electric stresses. Standard accelerated aging tests (temperature and voltage) of MPPF capacitors have been performed with the aim to evaluate the dielectric performance and thus the capacitor lifetime. The statistical approach showed that the failure mode may be represented by two parameter Weibull distribution and the experimental approach proved that long capacitor deteriorates faster than a plate-shaped having the same features. Although capacitors with long geometry seem to have a poor pulse handling performance, we found that the quality of the, end-edge contact is strongly ...
Sprayforming offers the possibility to produce a variety of preforms in a single step directly from the melt. Numerous processing parameters ensure high flexibility but require detailed knowledge concerning the microstructure of sprayformed material depending on chemical composition and processing parameters. Within the current study fundamental investigations using unalloyed and low alloy steel grades (C15, C105, 100Cr6) for sprayforming of plates and billets have been performed concerning the influence of chromium and carbon content and selected processing parameters. Sprayformed preforms revealed austenite grain sizes up to 500 {mu}m depending on the development of porosity. Different types of porosity have been detected which can be associated with incomplete densification due to high cooling rates, solidification shrinkage and entrapped nitrogen. Atomisation gas pressure and carbon content are parameters of primary importance. (Abstract Copyright [2003], Wiley Periodicals, Inc.) ...
In coke-oven operations flue-gas valves are used to switch the regenerator function from rich gas firing to lean gas firing. Compared with the simple geometry of the other parts of the flow path, which comprise flues and regenerators, the narrow and winding passages of the flue-gas valves give rise to relatively high losses in pressure. Without the construction of high (and therefore expensive) chimneys, this means that operating problems may well arise due the inadequate suction capacity. The project focused on the theoretical and experimental analysis of a coke-oven flue-gas valve. The primary aim was to reduce the pressure drop through the valve without modifying its external geomerty. The internal flow characteristics created by different valve geometries under a variety of operating conditions were simulated using the commercial CFD code Fluent/UNS, which provided velocity and pressure distributions. A half-scale model valve was ...
Purpose: To evaluate MR artifacts of carotid artery stents and to optimize stent properties and sequence parameters. Material and Methods: Four carotid artery stents - Wallstent (mediloy), Precise (nitinol), ACCULINK (nitinol) and a stent prototype (nitinol) - were investigated in a flow model of the cervical vessels. The model was made of silicon tubing and a flow pump that produces realistic flow curves of the carotid artery. To investigate the effects of magnetic susceptibility and radiofrequency induced shielding artifacts, turbo spin echo and gradient echo sequences as well as CE-MRAs were measured. To improve the visualization of the stent lumen in a CE-MRA, flip angle as well as geometry and covering of the stent prototype were altered. Results: Susceptibility artifacts in stents of the carotid artery only influence the lumen visualization at the proximal and distal end of the braided mediloy stent. A change of stent coverings has no significant influence on ...
Ethnopharmacological relevanceHLXL is a traditional Chinese medicine that has long been used in folk medicine for the treatment of chronic inflammatory diseases....Full Text Available
isotherme, dans un courant d'azote ou sous vide entretenu. I t. Comptes Rendus Scientific Academy, Paris, Vol. 265 pyrolyse du carbonate de calcium, ...
In order to practice a design-by-analysis of thermohydraulics design of BWR fuel rod bundles, the subchannel analysis would play a major role. There, the immediate concern is improvement in its predictive capability of CHF due in particular to the film dryout (boiling transition phenomena: BT) on the fuel rod surface. Constitutive equations in the subchannel analysis formulation are responsible for the quality of calculated results. The constitutive equations are a result of integration of the local and instantaneous description of two-phase flows over the subchannel control volume. In general, they are expressed in terms of subchannel-control-volume- as well as area-averaged two-phase flow state variables. In principle the information on local and instantaneous physical phenomena taking place inside subchannels must be counted for in the algebraic form of the equations on the basis of a more mechanistic modeling approach. They should include also influences of the multi-dimensional ...
The aim of this work is to account for the effects of the high temperature oxidation of metals on their microstructure and their mechanical properties. 'Model' materials like pure nickel, pure iron and the Ni-20Cr alloy are studied. Nickel foils have been oxidised at 1000 C on one side only in laboratory air, the other side being protected from oxidation by a reducing atmosphere. After the oxidation treatment, the unoxidized face was carefully examined by using an Atomic Force Microscope (AFM). Grain boundaries grooves were characterised and their depth were compared to the ones obtained on the same sample heat treated in the reducing atmosphere during the same time. They are found to be much deeper in the case of the single side oxidised samples. It is shown that this additional grooving is directly linked to the growth of the oxide scale on the opposite side and that it can be explained by the diffusion of the vacancies produced at the oxide scale - metal interface, ...
As the jump from 2D to 3D, seismic exploration lives a new revolution with the use of converted PS waves. Indeed PS converted waves are proving their potential as a tool for imaging through gas; lithology discrimination; structural confirmation; and more. Nevertheless, processing converted shear data and in particular determining accurate P and S velocity models for depth imaging of these data is still a challenging problem, especially when the subsurface is anisotropic. To solve this velocity model determination problem we propose to use reflection travel time tomography. In a first step, we derive a new approximation of the exact phase velocity equation of the SV wave in anisotropic (TI) media. This new approximation is valid for non-weak anisotropy and is mathematically simpler to handle than the exact equation. Then, starting from an isotropic reflection tomography tool developed at Lt-'P, we extend the isotropic bending ray tracing method to the anisotropic case and we ...
Experiments for lifetime prediction of the first wall are being carried out within the framework of the European fusion reactor programme. Defects such as notches and cavities may develop in the first wall and may initiate under cyclic thermal stress cracking processes which may reduce the service life of the material. For examination of crack growth, specimens with defined initial notches were prepared and subjected to cyclic thermal loads. The paper shows that the eddy current method is suitable for detecting and revealing the crack growth processes even under conditions of complex geometry, as e.g. cracks in inner bores. The experiments indicated particularly susceptible, critical spots in the first wall and yielded crack growth rates of use for lifetime calculations. (orig./CB) [Deutsch] Im Rahmen des europaeischen Fusionsreaktorprogramms werden Untersuchungen zur Lebensdauervorhersage der Ersten-Wand durchgefuehrt. Die Erste-Wand kann ...
The TTT diagrams describing the beta to alpha isothermal transformation have been made by isothermal dilatometry for pure uranium and 21 alloys based on chromium, silicon, molybdenum, iron, aluminium, zirconium. The thermal cycle preceeding the isothermal...
In addition to their use in high-speed ovens, microwaves are also finding applications in industrial manufacture, quality control and storage - anywhere where the high-frequency transmission or reflection properties of a material can be exploited. Microwaves are also being used in medical applications for the characterization of certain type of tumours. They are also being used in research into ultrasonic cavitation. (authors) 5 refs.
In order to conserve vaccines in hot countries a solar refrigerator has been made by a French university. It is a photothermal refrigerator without batteries. It uses two gases: ammonia and calcium chloride. The refrigerator is autonomous and can work eleven days without sun. (N.C.)
The resulting emissions of the firing of ceramic products of all type are described, the factors are enumerated to diminish the emissions in the kilns and the technologies applied in the kilns to reduce these emissions while carrying out energy saving are described briefly. (author)
The high-speed direct-injection diesel engine for passenger cars has been a resounding success in the marketplace in the last few years. This was due to an intensive development process as a result of which the direct-injection diesel engine for passenger cars is currently setting new standards with regard to performance and fuel consumption in spite of the constant tightening of emission regulations. Of particular importance in this context is exhaust gas recirculation (EGR). This technology permits a considerable reduction in nitrogen oxide emissions, which are especially critical in the case of the direct-injection diesel engine. In addition, continuing development of supercharging technology, in particular the turbocharger with variable turbine geometry, have allowed further improvement of the full-load behaviour and the engine response and a considerable reduction in the fuel consumption of direct-injection diesel engines. This FVV paper deals with the ...
Objective: To compare the efficiency of dual energy subtraction and conventional direct digital radiography in signal detecting ability. Methods: 200 plastic balls which were 4 mm in diameter were taken as signals and were placed on a 10 cm thick plastic board and the right upper thorax of a healthy volunteer. The signals were examined by DES and CDR separately and were estimated by 3 radiologists with 5-value-differentiation method. ROC curve analysis was made by ROC kit software. Results: when signals on plastic board were detected by CDR and DES, ROC curve analysis indicated that there was no significant difference (P=0.4851 > 0.05, two-tailed) between the area under the ROC curves of the two methods (Az=0.9931 for CDR and Az=0.9879 for DES). The difference was significant (P=0.0002 <0.01, two-tailed) between the area under the ROC curves of CDR and DES (Az=0.7276 for CDR and Az=0.8561 for ...
For a simplicial manifold we construct the differential geometry structure and use it to investigate linear connections, metric and gravity. We discuss and compare three main approaches and calculate the resulting gravity action functionals. (author)
We show how one can associate to a given class of finite type G-structures a classifying Lie algebroid. The corresponding Lie groupoid gives models for the different geometries that one can find in the class, and encodes also the different types of symmetry groups.
The influence of geometry and operating conditions of the centrifugal compressor stage on the radial gas force is determined on the basis of the theoretical method and calculation program using experimental boundary conditions.
An explicite PN solution of the multi-dimensional homogeneous neutron transport equation is given by expanding the angular flux into a series of geometry-independent spherical harmonics operators. An algorithm is developed for representing the spherical harmonic operators in orthogonal curvilinear coordinates. The general formulae are applied to two-dimensional spherical geometry; detailed P3 formulae are given. (orig.).
Tensor network states are used to approximate ground states of local Hamiltonians on a lattice in D spatial dimensions. Different types of tensor network states can be seen to generate different geometries. Matrix product states (MPS) in D=1 dimensions, as well as projected entangled pair states (PEPS) in D>1 dimensions, reproduce the D-dimensional physical geometry of the lattice model; in contrast, the multi-scale entanglement renormalization ansatz (MERA) generates a (D+1)-dimensional holographic geometry. Here we focus on homogeneous tensor networks, where all the tensors in the network are copies of the same tensor, and argue that certain structural properties of the resulting many-body states are preconditioned by the geometry of the tensor network and are therefore largely independent of the choice of variational parameters. Indeed, the asymptotic decay of correlations in homogeneous MPS and ...
We present first worldline numerical results for the nontrivial interplay between geometry and temperature dependencies of the Casimir effect. We show that the temperature dependence of the Casimir force can be significantly larger for open geometries (e.g., perpendicular plates) than for closed geometries (e.g., parallel plates). For surface separations in the experimentally relevant range, the thermal correction for the perpendicular-plates configuration exhibits a stronger parameter dependence and exceeds that for parallel plates by more than an order of magnitude at room temperature. This effect can be attributed to the fact that the fluctuation spectrum for closed geometries is gapped, inhibiting the thermal excitation of modes at low temperatures. By contrast, open geometries support a thermal excitation of the low-lying modes in the gapless spectrum already at low ...
A "hemispheres-in-cell" geometry is provided for prediction of colloid retention during transport in porous media. This new geometry preserves the utilities provided in the Happel sphere-in-cell geometry; namely, the ability to predict deposition for a range of porosities, and representation of the influence of neighboring collectors on the fluid flow field. The new geometry, which includes grain to grain contact, is justified by the eventual goal of predicting colloid deposition in the presence of energy barriers, which has been shown in previous literature to involve deposition within grain to grain contacts for colloid:collector ratios greater than approximately 0.005. In order to serve as a platform for predicting deposition in the presence of energy barriers, the model must be shown capable of quantitatively predicting deposition in the absence of energy barriers, which is a requirement that was ...
Since several years, several manufacturers of circuit breakers from various countries (South Africa, UK, The Netherlands, USA..) try to impose in accommodations a highly sensitive electronic-type of differential circuit-breaker initially devoted to industrial installations where qualified and experienced professionals are present. This technical paper presents first the principles of the classical electromechanical circuit breakers and of the electronic circuit breaker, and then compares their relative efficiency and level of safety in residential use conditions (grounding schemes, voltage drops, rupture of the neutral conductor, rupture of the phase conductor, overvoltages). (J.S.)
In order to promote the use of natural gas air-conditioning systems in the tertiary sector, Gaz de France (the French gas utility) in association with Electricite de France (EdF) and the French chamber of council engineers (CICF) have created the Acerclim organization which aims at certifying the quality of the design, realization and exploitation of air processing and air-conditioning installations according to the ISO 9001 criteria. This article describes this quality procedure named 'CHSB Air'. (J.S.)
The Purex process and the fluorescence spectrometry are first recalled, then uranyl fluorescence is studied in a pure nitric medium without other elements to establish a theoretical model, allowing the description of uranium fluorescence signal with a general equation. The influence of different parameters (temperature, inhibitors, dynamic quenching of iron and cerium) is investigated to develop the model. A quantitative analysis method without addition of reagents is proposed to validate the model.
The UFIP (French Petroleum Industry Association) studies concerning polluted sites and soils and their rehabilitation are presented: characterization of the admissible maximum fuel or gas oil content in the ground, the issue of time effects, and the risks it may induce for public health; study on the various pollutant impacts on the environment (underground waters, biotope...); approach to the development of a dynamical model describing these phenomena and their influence on man, in order to derive consistent and reasonable decontamination objectives
The fundamental product of tetracycline hydrochlorine gamma radiolysis was separated in its solid state. From the results of spectroscopic studies it has been established that it is des-N,N-dimethylaminotetracycline.
This document is the safety analysis made by the national association of the local commissions of information about nuclear activities (ANCLI), about the safety of graphite storage silos of Saint Laurent des Eaux nuclear facility. The analysis covers: the operation safety and the accident hypothesis, the monitoring of indoor and outdoor contamination in routine situation, the geotechnical characteristics of the site environment, the isotopic inventory and the estimation of radioactivity in routine and accidental situation, the estimation of doses received by the population in accidental situation and the internal emergency plan. After examination of these different points, the scientific committee of the ANCLI considers that a new global evaluation of risks, which integrates more recent exposure data, has to be carried out. (J.S.)
An optimization of fuel bundle geometry using the subchannel code ASSERT is performed in support of Candu fuel design to enhance the thermohydraulics performance. The new bundle design is based on a reference CANFLEX bundle with changes to the centre and inner-ring element diameters and pitch-circle diameters (PCDs) of various element rings. Different methods of varying the PCDs for reaching the optimized geometry are considered in an attempt to minimize the optimization effort. The optimized geometry in the present analysis is the one that maximizes the dryout power and that has simultaneous CHF (critical heat flux) initiation involving more than one subchannel rings. (authors)
Average emittance data for ion beams extracted from cesium-sputter negative ion sources equipped with spherical, ellipsoidal, and cylindrical geometry cesium-surface ionizers are presented. The attributes of the respective source geometries are described in terms of their cesium ion optical properties. The results of recent measurement of the emittances of momentum-analyzed beams extracted from the ellipsoidal geometry source are also presented. These measurements indicate the presence of a species-dependent effect. The effect is believed to be attributable to differences in the energy spreads of the respective negative ion beams introduced by the sputter generation process.
Average emittance data for ion beams extracted from cesium-sputter negative ion sources equipped with spherical, ellipsoidal, and cylindrical geometry cesium-surface ionizers are presented. The attributes of the respective source geometries are described in terms of their cesium ion optical properties. The results of recent measurement of the emittances of momentum-analyzed beams extracted from the ellipsoidal geometry source are also presented. These measurements indicate the presence of a species-dependent effect. The effect is believed to be attributable to differences in the energy spreads of the respective negative ion beams introduced by the sputter generation process. 11 refs., 8 figs.
In a prospective study 102 patients with malignant tumors of the tongue, oropharynx, hypopharynx, and larynx were staged by means of MRI. Special attention was directed at those tumour extensions that could influence the treatment strategy. The MR findings were correlated with the results of palpation, endoscopy, ultrasound, computerised tomography and histopathological findings. MRI showed a good delineation of pT{sub 2} to pT{sub 4} tumours. However, visualisation of small tumours in the soft palate, the tonsils, the pyriform sinuses and vocal cords was difficult. In conclusion our results suggest that in addition to endoscopy MRI is a valuable tool for the examination of tumours of tongue, oropharynx, hypopharynx and larynx. (orig.) [Deutsch] In einer prospektiven Studie wurden 102 Patienten mit malignen Tumoren der Mundhoehle, des Oro- und Hypopharynx sowie des Larynx mit der Mgnetresonanztomographie (MRT) untersucht, wobei besonders Wert ...
Background. New-generation drug-eluting stents (DES) may solve several problems encountered with first-generation DES, but there is a lack of prospective head-to-head comparisons between...Full Text Available
The IWA and ISWA congresses organized in Paris in july showed the latest research developments in the field of water and wastes management. The water sector is more mature than the waste sector but for both a closer association of the public and private is increasing. A summary of the presentations in successively the water and the wastes management is proposed bringing an analysis of the international situation and regulations. (A.L.B.)
This text presents the annotations of all different articles of the law text concerning the sustainable development of radioactive materials and wastes. (A.L.B.)
General relativity postulates the Minkowski space-time to be the standard flat geometry against which we compare all curved space-times and the gravitational ground state where particles, quantum fields and their vacuum states are primarily conceived. On the other hand, experimental evidences show that there exists a non-zero cosmological constant, which implies in a deSitter space-time, not compatible with the assumed Minkowski structure. Such inconsistency is shown to be a consequence of the lack of a application independent curvature standard in Riemann's geometry, leading eventually to the cosmological constant problem in general relativity. We show how the curvature standard in Riemann's geometry can be fixed by Nash's theorem on locally embedded Riemannian geometries, which imply in the existence of extra dimensions. The resulting gravitational theory is more general than general relativity, ...
... turbine blade heat-transfer and study the heat-transfer augmentation in idealized geometry and its ... responsible for heat transfer augmentation. ...
Geometra'. Scrape Geom- ett_,. Used By: Theoretical. FEM Weight. Apply Linear Delta ...... that the FEM is geometri- cally linear, the differences between ...
The invention of non-Euclidean geometries is often seen through the optics of Hilbertian formal axiomatic method developed later in the 19th century. However such an anachronistic approach fails to provide a sound reading of Lobachevsky's geometrical works. Although the modern notion of model of a given theory has a counterpart in Lobachevsky's writings its role in Lobachevsky's geometrical theory turns to be very unusual. Lobachevsky doesn't consider various models of Hyperbolic geometry, as the modern reader would expect, but uses a non-standard model of Euclidean plane (as a particular surface in the Hyperbolic 3-space). In this paper I consider this Lobachevsky's construction, and show how it can be better analyzed within an alternative non-Hilbertian foundational framework, which relates the history of geometry of the 19th century to some recent developments in the ?eld.
Many solutions of General Relativity appear to allow the possibility of time travel. This was initially a fascinating discovery, but geometries of this type violate causality, a basic physical law which is believed to be fundamental. Although string theory is a proposed fundamental theory of quantum gravity, geometries with closed timelike curves have resurfaced as solutions to its low energy equations of motion. In this paper, we will study the class of solutions to low energy effective supergravity theories related to the BMPV black hole and the rotating wave-D1-D5-brane system. Time travel appears to be possible in these geometries. We will attempt to build the causality violating regions and propose that stringy effects prohibit their construction. The proposed chronology protection agent for these geometries mirrors a mechanism string theory employs to resolve a class of naked singularities. ...
Bone integrity and mineral status were studied with a noninvasive method in uremic patients with severe secondary hyperparathyroidism undergoing maintenance hemodialysis.
The presented paper describes the formulation of the fractional mass balances which are used to calculate the concentration and size distribution of char in the balance cells of a circulating fluidized bed boiler. In case of using the shrinking core model additionally the distribution of conversion of the char particles is calculated. Basically two reaction models (a shrinking particle and a shrinking core model) are available to describe the combustion process. The model considers all essential physico/chemical phenomena (primary fragmentation, attrition, mass transfer to gas phase) which have to be taken into account for the description of the combustion process. The model is part of an overall simulation program for circulating fluidized bed boilers. This engineering simulator has been developed to return the main performance parameters of such systems like temperature along the furnace height, size distribution of balanced solid components, heat flows at the different heat ...
Two-wave mixing in sillenite crystals such as bismuth silicon oxide (Bi12SiO20) and bismuth titanium oxide (Bi12TiO20) of (001)- and (221)-cuts for counterpropagating geometry was studied within the frame of slowly varying amplitude approximation. Electrooptic, photoelastic, piezoelectric, self-diffraction effects and optical activity were taken into account.
The motion of a test particle moving in an interior static spherically symmetric geometry is investigated. The author concludes that an oscillatory motion with the test particle changing its motion from a free fall towards the center to an outward radial motion can not exist for any static interior spherically symmetric model.
Two sets of experiments have been performed in sodium with two seven pin electrically heated bundles: the first with a nominal arrangement, the second with one dummy pin enlarged 20% in diameter in peripheral position. In this paper a rapid review of experimental results and theoretical works, related to the temperature distribution in these geometries, is presented together with a short description of the developed test section technology.
Log Gromov-Witten invariants have recently been defined separately by Gross and Siebert and Abramovich and Chen. This paper provides a dictionary between log geometry and holomorphic exploded manifolds in order to compare Gromov-Witten invariants defined using exploded manifolds or log schemes. The gluing formula for Gromov-Witten invariants of exploded manifolds suggests an approach to proving analogous gluing formulas for log Gromov-Witten invariants.
We discuss three distinct topics of independent interest; one in enumerative combinatorics, one in symmetric function theory, and one in algebraic geometry. The topic in enumerative combinatorics concerns a q-analog of a generalization of the Eulerian polynomials, the one in symmetric function theory deals with a refinement of the chromatic symmetric functions of Stanley, and the one in algebraic geometry deals with Tymoczko's representation of the symmetric group on the cohomology of the regular semisimple Hessenberg variety of type A. Our purpose is to explore some remarkable connections between these topics.
Ionization counters employing Bragg curve spectroscopy have been constructed for use in a 4? geometry. These detectors compare very favorably in terms of both energy and charge resolution with small solid angle devices. These detectors have a large dynamic range because they are backed by scintillation detectors, and are thus capable of detecting and identifying particles with energies from 1 MeV/nucleon up to 200 MeV/nucleon.
Ionization counters employing Bragg curve spectroscopy have been constructed for use in a 4{pi} geometry. These detectors compare very favorably in terms of both energy and charge resolution with small solid angle devices. These detectors have a large dynamic range because they are backed by scintillation detectors, and are thus capable of detecting and identifying particles with energies from 1 MeV/nucleon up to 200 MeV/nucleon. (orig.).
Ionization counters employing Bragg curve spectroscopy have been constructed for use in a 4#pi# geometry. These detectors compare very favorably in terms of both energy and charge resolution with small solid angle devices. These detectors have a large dynamic range because they are backed by scintillation detectors, and are thus capable of detecting and identifying particles with energies from 1 MeV/nucleon up to 200 MeV/nucleon. (orig.).
We consider a simple model of d families of scalar field interacting with geometry in two dimensions. The geometry is locally flat and has only global degrees of freedom. When d0 it collapses to a one dimensional manifold. The model has some, but not all, of the characteristics believed to be features of the full theory of conformal matter interacting with quantum gravity which has local geometric degrees of freedom.
The neutron transport equation in Cartesian geometry possesses straight line characteristics along which the streaming operator can be written as a full differential in terms of the characteristic length. This idea was used by Lathrop to develop the step characteristic method, which he showed to be positive definite but less accurate than conventional Diamond-Difference schemes. Several authors since then have developed new methods utilizing the characteristic curves (including non-Cartesian geometry). A Linear Characteristic Method, based on a more consistent linear representation of the incoming-surface and within-cell angular flux, has been developed and tested in two-dimensional geometry producing highly accurate and computationally efficient results. A similar linear method, with several modifications, was developed for three-dimensional Cartesian geometry, and implemented in ORNL`s production code ...
In order to avoid the use of catalysts in the process of auto-thermal reforming, it is possible to adopt a running at high temperature. In this study are presented the results of simulations of an auto-thermal/recuperator hybrid reforming system; these results are obtained with the oxidation model of alkanes developed by Ranzi and Faravelli. An isothermal configuration at high temperature improves the hydrogen yield and avoids the formation of soots. The analysis of the powers to be furnished to assure such an experimental mode, and the global approach of the fuel cell system show that the management of the heat exchanges is a key parameter in this process. (O.M.)
Similar to many other countries, an educational reform anchored in a managerial discourse was proposed in Israel in 2004 by the Dovrat Committee, encouraged by the 'inter-state education gap' social problem that economist Dan Ben-David formulated on the basis of international examinations, such as PISA and TIMMS. Through a neo-Weberian approach this study follows the construction of a managerial discourse from the 1970s onwards that led to the Dovrat report. In the first period, managerial discourse was constructed around decentralization, parent choice and school autonomy 'social objects' by an expanding reformist network of educational scholars and figures from the Ministry of Education and local authorities. The pervasion of managerial discourse paved the way for the nomination of Shlom...
The new generation of performing rechargeable lithium-ion batteries (``rocking-chair``-type) are penalized by important self-output phenomena linked with the use of highly oxidizing positive electrodes. In order to limit this problem in LiMn{sub 2}O{sub 4}/C batteries, two different passivation techniques were used in order to limit the surface contact between the positive electrode and the electrolyte. Thanks to these treatments, a significant reduction of the percentage of irreversible capacity losses is effectively observed. (J.S.) 3 refs.
This poster presentation gave an overview of the subaqueous deposition of reactive mine tailings in the open trench Don Rouyn, located near Rouyn-Noranda, Quebec. The author began by providing a brief background of subaqueous mine tailing storage, and discussed the interest of the Don Rouyn trench. The site was described according to geomorphological and geological aspects. The hydrology conditions existing at the site were mentioned, and the results of the hydrology analysis performed were indicated. Close monitoring of the situation was maintained, and the chemical and physical stability of the tailings were evaluated. The conditions that prevailed both before and after the flooding of the site were explained. Water quality is being monitored, and the results obtained at this site might be used at other locations. 40 figs.
The elastic behaviour of YBaCuO specimens has been studied by very low-frequency isothermal internal-friction measurements. A relaxation peak is observed which is attributed to oxygen atom jumps, between A(1/2 0 0) and B(0 1/2 0) sites, in the CuO planes of the orthorhombic phase. A limit relaxation time {tau}{sub 0}, 2.6 {center dot} 10{sup -15}s, and an activation energy, 1.3eV, have been obtained from the shift of the maximum damping frequency observed when the measurement temperature is changed. The proposed values for the limit relaxation time and the activation energy are in good agreement with those previously proposed in the literature.
Today, component oriented middlewares are used to design, develop and deploy easily distributed applications, by ensuring the heterogeneity, interoperability, and reuse of the software modules, and the separation between the business code encapsulated in the components and the system code managed by the containers. Several standards answer this definition such as: CCM (CORBA Component Model), EJB (Enterprise Java Beans) and .Net. However these standards offer a limited and fixed number of system services, removing any possibility to add system services or to reconfigure dynamically the middleware. Our works propose mechanisms to add and to adapt dynamically the system services, based on a reconfiguration language which is dynamically adaptable to the need of the reconfiguration, and on a tool of dynamic reconfiguration, a prototype was achieved for the OpenCCM platform, that is an implementation of the CCM specification. This work was partially financed by the european project ...
At the 7th Healthy Buildings Conference, which was held in Singapore, 7-11 December 2003, more than 500 articles to improve public health and productivity of workers in buildings and the performance of installations. Special attention is paid to indoor air quality and thermal comfort in relation to energy efficiency. [Dutch] Op de laatste Healthy Buildings conferentie, december 2003 in Singapore, werden meer dan 500 artikelen gepresenteerd over het creeren van gezonde, productiviteit verhogende gebouwen en installaties. Deze keer lag de nadruk op binnenluchtkwaliteit en thermisch binnenklimaat, onder andere op het aspect energiezuinigheid. Opvallend was ook de aandacht die de problemen met binnenluchtkwaliteit in ontwikkelingslanden kreeg.
The last developments in lithium batteries design have demonstrated the advantages of graphite: competitive cost, flat output curve, high capacity thanks to the obtention of a final compound close to LiC{sub 6}, good behaviour during cycling and a high mass energy. However, these advantages are slightly tarnished by parasite secondary reactions during the evolution of the element. Two different cases are encountered: the formation of a passivation layer (loss of Li ions and formation of irreversible bounds) and the formation of a passivation layer with a reaction between graphite and the solvent (partial destruction of the graphite crystal lattice). In the first case, the theoretical graphite insertion capacity remains at 372 mAh/g while in the second case the insertion capacity is greatly reduced. Abstract only. (J.S.)
Industrial premises bear more and more important thermal constraints which can commonly reach 150 W/m{sup 2} and more. The reason is the general development of automation and automatic devices and the better thermal insulation of buildings. Production quality requires also more and more strict ambient conditions (temperature, humidity, air quality, air flow etc..). Thus, the air-conditioning market in the industrial sector is more linked to economic factors such as productivity and profit than to thermal comfort of workers. However, the air-conditioning potentialities in the industrial sector remains under-exploited in France. This paper analyzes the reasons of this situation in terms of investments and equipments. (J.S.)
This book brings together the 103 presentations given at the 2. conference of the international institute of refrigeration (IIF/IIR) about air conditioning in high rise office buildings. The main themes are: design of air conditioning equipment for high buildings; air quality and thermal comfort inside these buildings; constraints and possible improvements of the refrigeration equipment used; energy conservation; fire protection and smokes detection. All themes are presented both on the technical and economical points of view and concern more particularly the buildings of Chinese cities. This publication is available both on the book and CD-Rom forms. (J.S.)
This two-tomes book brings together the 108 presentations given at the first conference of the international institute of refrigeration (IIF/IIR) about air conditioning in high rise office buildings. The main themes are: general design and control systems, including split systems, radiant panels, fluctuating and gravity ventilation etc..; energy consumption, optimization and heat recovery; cold storage for peak shaving, including ice slurry circulation; indoor air quality; fire and smokes protection, protection against chimney effects and lighting spots; use of fuzzy logic and of neural networks. It includes also a description of the high rise building situation and works in progress in China, Japan and in some other countries. (J.S.)
MPA research activities focus on fracture prevention and on the development of a generally applicable method of component integrity testing which, independent of the safety relevance of the components involved, is also part of ageing management. (orig.) [German] Die Forschungsaktivitaeten an der MPA im Hinblick auf die Erhoehung der Sicherheit und Zuverlaessigkeit komplex beanspruchter Bauteile orientieren sich an den Grundgedanken des Basissicherheitskonzepts (Prinzip des Bruchausschlusses). Zielsetzung war dabei die Entwicklung eines allgemein anwendbaren Nachweisverfahrens zur Komponentenintegritaet, das, abhaengig von der sicherheitstechnischen Relevanz der zu betrachtenden Komponenten, auch Bestandteil des Alterungsmanagements ist. (orig.)
The report published in 2003 by the European committee on the risk of irradiation (C.E.R.I.) criticizes a part of the ICRP recommendations relative to the internal contaminations.Consequently, I.R.S.N. wishes to supply its own analysis. The present report points the questions linked to the internal contamination and to the difficulties inherent to the risk incurred after chronic exposure.Consequently it does not treat all the problems of the workers and populations radiation protection. (N.C.)
This issue of Barrages newsletter comprises three articles. The first article treats of the quality approach relative to the organization of the inspections of big and medium size dams. It summarizes the improvements of this approach added in 2003 after analysis of the experience feedback. The second article presents the conclusions of the decennial and annual inspections of dams in exploitation. Only the observations requiring a special follow-up are reported. The last article summarizes the activities of the control services for the third quarter of 2003: decennial and annual visits, important facts, administrative instructions, studies, projects and works, organization of services, technical studies etc.. (J.S.)
French ... Orig. Title Scintigraphie osseuse quantifiee chez l'enfant et l'adolescent - repartition selon l'age des taux de fixation de diverses pieces osseuses normales.
The authors introduce the above electric car. They deal particularly with the vehicle concept, the energy consumption and the emission balance. (orig.).
French English ... Orig. Title Imagerie IRM des lesions focales hepatiques avec les antennes de surface en reseau phase (phased array): apnee ou imagerie haute resolution?.
Field campaigns were conducted in 1981 and 1982/83 on the Dutch coast near Egmond. Measurements were made of surface elevations, water velocities and sediment concentrations in 3 to 8 surf zone locations and 2 to 5 offshore locations simultaneously. A des...
Neonatal exposure to diethylstilbestrol (DES) can alter the structure of the testicular excurrent ducts in rats. We characterized these changes according to dose and time posttreatment and established...Full Text Available
ObjectivesWe undertook a meta-analysis to assess outcomes for drug-eluting (DES) and bare metal stents (BMS) in percutaneous coronary intervention (PCI) for unprotected...Full Text Available
Coasts are exposed to chronic or accidental pollutions by hydrocarbons. The aim of this study is to show the importance of the microbial layers (stratified sedimentary systems) in the biodegradation of the hydrocarbons. (A.L.B.)
This conference is composed of 21 communications and 21 posters in the domain of building ventilation and indoor air quality; the main themes are: indoor air quality assessment and optimization; performance enhancement and optimization of ventilation systems and equipment; ventilation systems for renovated and rehabilitated buildings; French and European regulations, standardizations and certifications; experimental and numerical simulation studies concerning ventilation systems, air flow, temperature distribution, air quality, thermal comfort and ventilation-induced acoustic levels
Two of the working sessions of the meeting were devoted to aspects of international atomic energy law; the international character of the meeting was also reflected by the home countries of the members of the panel discussion concluding the working sessions. There was substantial reason to put emphasis on the international dimension of the topics discussed. In June 1994, the Nuclear Safety Convention had been signed in Vienna by diplomatic representatives of the signatory countries, and this Convention marks a signpost in the history of international atomic energy law. At the time the meeting was held, negotiations for improving the international nuclear lability law, which had been dragging on since 1989, had come to a stalemate. The meeting offered a suitable forum for taking a scientific approach to tackle the complex problems involved in reshaping the law on nuclear safety and nuclear liability. The third working session of the meeting has been discussing topics relating to the ...
CNG vehicles suffer from an uncontrolled temperature rise of the gas inside the tank during the filling process and heat exchange with the environment leads to variable filling levels. A partly filled tank reduces the range of CNG vehicles and works as a impediment to the spreading of environmentaly more friendly CNG vehicles. The increase of the pressure inside the tank combined with a prolongation of the filling time beyond three minutes can reduce the deficit of the filling process. For economic reasons the time required for refuelling should be as short as possible without the need to operate the filling station with a critical pressure. To meet this target the current technique requires further improvement. (orig.) [Deutsch] Die betriebliche Praxis bei Tankvorgaengen von Erdgasfahrzeugen zeigt, dass waehrend des Tankvorganges die Temperatur des getankten Erdgases im Fahrzeugtank ansteigt. Waehrend und nach Beendigung ...
Diseases of the mandible affect the soft tissues aside from the osseous manifestation. This can be shown clearly and in great detail by magnetic resonance imaging (MRI). MRI is the gold standard in the diagnostic evaluation of any internal derangement of the temporomandibular joint. Dental MRI requires high resolution techniques and in some cases also intravenous administration of contrast material. These techniques allow delineation of the neurovascular bundle. In the past few years new indications were formulated, for example, the evaluation of the integrity of the inferior alveolar nerve in trauma and in radicular cysts. New quantitative methods now enable insights into the pathophysiology. The objective of this review is to communicate accepted indications for MRI of the mandible and to present innovative applications. (orig.) [German] Mandibulaere Erkrankungen beteiligen neben dem Knochen Weichteilstrukturen, die sich mit der MRT klar und detailreich darstellen lassen. In der ...
In this study, the effects of channel surface wettability, cross-sectional geometry and orientation on the two-phase flow in parallel gas channels of proton exchange membrane fuel cells (PEMFCs) are investigated. Ex situ experiments were conducted in flow channels with three different surface wettability (hydrophilically coated, uncoated, and hydrophobically coated), three cross-sectional geometries (rectangular, sinusoidal and trapezoidal), and two orientations (vertical and horizontal). Flow pattern map, individual channel flow variation due to maldistribution, pressure drop and flow visualization images were used to analyze the two-phase flow characteristics. It is found that hydrophilically coated gas channels are advantageous over uncoated or slightly hydrophobic channels regarding un...
Fugitive dust emissions from stockpiles in the open storage yards of industrial zones and the subsequent atmospheric dust dispersion have brought about many ecological and economical problems. This paper introduces a new approach to reduce pollutant emissions by simply changing pile configuration and without affecting the operational activity on these parks. Flow around piles of different geometries and for various wind conditions was studied using previously validated Computational Fluid Dynamic (CFD) simulations. Different pile height scenarios were investigated corresponding to a constant material volume and a fixed angle of repose under various wind magnitudes. The results obtained were integrated in order to evaluate the rate of dust emissions for the various configurations considered. It was found that, for the range of wind conditions and pile dimensions tested, an optimal geometry exists which corresponds to the lower emissions rate. 13 ...
A numerical package called RESID has been assembled to calculate the residual stresses in VAWT blades induced during cold forming. Using a strength of materials - elementary beam theory approach, RESID models the material response with a bilinear stress-strain curve, and the cross-sectional geometry with an array of area increments. Through an iterative solution procedure residual stresses are predicted for a specified final radius of curvature or applied bending moment. RESID results are compared to theoretical solutions for simple geometries and with MARC Finite element results for VAWT blade geometries. Calculating residual stress levels, determining acceptable residual stress levels, and a method of reducing residual stresses are discussed. A complete listing and sample run are included in the appendicies.
There is an ever increasing demand to perform flow simulations that incorporate the complete details of geometry as well as sophisticated flow physics. This has led to the development of numerical algorithms that can simulate the actual flow phenomena with greater fidelity. However, the success of these algorithms hinges on the grid that models the geometry. Grid generation methods for 2-D models have long existed and the general lack of complexity of the simpler 2-D models has not quite challenged the efforts in this area. However, demands for generating better 3-D geometric models for flow simulations involving complex geometries have completely changed the perspective of grid generation strategies. As a consequence, grid generation efforts have earned equal significance as that of numerical solver efforts.
{The determination of cluster masses is a complex problem that would be aided by information about the cluster shape and orientation (along the line-of-sight).} {It is in this context, that we have developed a scheme for identifying the intrinsic morphology and inclination of a cluster, by looking for the signature of the true cluster characteristics in the inter-comparison of the different deprojected emissivity profiles (that all project to the same X-ray brightness distribution) and by using SZe data when available.} {We deproject the cluster X-ray surface brightness profile under the assumptions of four different geometry and inclination configurations for the observed system; these 4 configurations correspond to four extreme geometry+inclination scenarios. The deprojection in question is performed by the non-parametric algorithm DOPING. The formalism is tested with model systems and then is applied to a sample of 24 clusters. While the ...
Using a quasi-static approach valid for Stefan numbers less than one, we derive approximate equations governing the movement of a phase change front for materials which generate internal heat. These models are applied for both constant surface temperature and constant surface heat flux boundary conditions, in cylindrical, spherical, plane wall and semi-infinite geometries. Exact solutions with the constant surface temperature condition are obtained for the steady-state solidification thickness using the cylinder, sphere, and plane wall geometries which show that the thickness depends on the inverse square root of the internal heat generation. Under constant surface heat flux conditions, closed form equations can be obtained for the three geometries. In the case of the semi-infinite wall, we show that for constant temperature and constant heat flux out of the wall conditions, the solidification layer grows then remelts. ...
Purpose: To assess the new method of 3-dimensional echocardiography in comparison to the 'gold standard' MRI as to its ability to calculate left ventricular volumes in patients with congenital heart disease. Materials and methods: Eighteen patients between the ages of 3.9 to 37.3 years (mean: 12.8{+-}9.7) with a geometrically abnormal left ventricle were examined using a 1.5 T scanner with a fast gradient-echo sequence (TR=14 ms, TE=2.6-2.9 ms, FOV=300-400 mm, flip angle=20 , matrix=128:256, slice thickness=5 mm, retrospective gating) in multislice-multiphase technique. Transthoracic 3D-echocardiography was performed with a 3.5 MHz transducer and a Tomtec {sup trademark} (Munich, Germany) system for 3D reconstruction. Results: Volume calculation was possible in all patients with 3D-echocardiography, but the muscle mass calculation only succeeded in 11 to 18 patients (61%) due to inadequate visualization of the entire myocardium. Comparing MRI and 3D-echocardiography, ...
Three new classes of finite, homogeneous and nonsingular solutions of Einstein's equations which have time-dependent expansion, shear and rotation are presented. The t-constant sections are of Bianchi type IX. The source of these geometries is a fluid which has not been thermalized. (Author).
An exact cosmological solution of Einstein's equations which has time-dependent rotation is presented. The t-constant sections are of Bianchi type II. The source of this geometry is a fluid which has not been thermalized. (Author).
Numerical calculations of static, switched, and radiofrequency (RF) electromagnetic (EM) fields considering the geometry and EM properties of the human body are used increasingly in MRI to explain...Full Text Available
The two-phase heat-transfer and pressure-drop characteristics of offset-strip-fin heat-exchanger geometries are examined using both experimental and analytical modeling techniques. Newly-obtained boiling-flow heat-transfer data are presented for two large-scale offset fin geometries at low-to-moderate wall-superheat conditions. Data for which nucleate boiling appeared to be completely suppressed were analyzed together with similar results for other offset fin surfaces to study the effects of channel dimensions on the convective evaporation component of the local heat transfer coefficient. Although these data were found to be well correlated in terms of modified forms of the F and Martinelli parameters used in previous studies of round-tube flows, a single F-factor correlation valid for all combinations of fin and channel dimensions did not appear to exist. The two-phase pressure-drop characteristics of offset-fin surfaces were found to be much ...
The aim of the present study focuses on experimentally demonstrating the efficacy of using angularly-variable fiber geometry to achieve the desired tissue-layer selection and probing depths with the further objective of enhancing the sensitivity and specificity of spectral diagnosis in stratified architectures that resemble human cervical epithelia. The morphological and biochemical features of epithelial tissue vary in accordance with tissue depths; consequently, the accuracy of spectroscopic diagnosis of epithelial dysplasia may be enhanced by probing the optical properties of this tissue. When correlated to cellular dysplasia, layer-specific changes in tissue optical properties may be deciphered by reflectance spectroscopy coupled with angularly-variable fiber geometry. This study addresses the utility of using such angularly-variable fiber geometry for resolving spatially-specific spectral signatures of tissue ...
BackgroundMolecular docking methods are commonly used for predicting binding modes and energies of ligands to proteins. For accurate complex geometry and binding energy estimation,...Full Text Available
BackgroundA relevant problem in drug design is the comparison and recognition of protein binding sites. Binding sites recognition is generally based on geometry often combined with...Full Text Available
The comprehensive survey explains the indications and the specific value of the modern tomographic modalities with respect to the various diagnostic issues. Numerous reproductions of CT, MRI, US scans illustrate the aspects discussed. (orig./CB) [German] Bildgebende Verfahren kommen bei der Abklaerung von Erkrankungen des weiblichen Urogenitaltrakts ergaenzend zu der klinischen Untersuchung zur Anwendung. Kongenitale Uterusanomalien werden primaer mit der HSG oder der Laparoskopie diagnostiziert. Zusaetzlich koennen der transvaginale US und in unklaren Faellen die MRT eingesetzt werden. Die Diagnose entzuendlicher Erkrankungen des weiblichen Genitaltrakts erfolgt in der Regel klinisch. Schnittbildverfahren werden bei therapieresistenten, komplizierten Faellen angewendet. Initial werden benigne Neoplasien des Uterus mit dem transvaginalen US abgeklaert. Eine Verdickung des Endometriums ist dabei ein ...
The relationship between short term relative sea-level oscillations and the reef, off-reef deposits geometry of an Upper Devonian third order sequence highstand of the Nisku Formation in west central Alberta was studied through the analysis of high resolution sequence stratigraphy. Hydrocarbon generation was reconstructed by total organic carbon values and migration patterns that were dependent on the geometry of three fourth order sequences. This stratigraphic reconstruction provided the key to recent hydrocarbon discoveries such as in the Brazeau southern reef margin.
An experimental technique is described which allows for parametric investigations of transient behavior of mobile core materials in a fuel bundle geometry. For the out-of-pile simulation of energy releases resulting from mild TOP- or LOF-accidents the exothermic reaction of an aluminium-oxide-thermite is used. Transient material relocation inside the test section is recorded by X-ray-cinematography. Results of some experiments recently performed close to conditions expected to be achieved during mild TOP-accidents are described in detail.
Self-magnetically insulated, high-voltage transmission lines are used in inertial confinement fusion particle accelerators in order to transmit power from the vacuum insulator to the diode. This paper describes a time-dependent 2-D code (MITL) for calculating (for planar or triplate geometries) the motion of test electrons through the tapered input or output convolutes of such lines. MITL results show that the electron canonical momentum in the direction of the flow changes as the electron passes through the convoluted geometry; it is suggested that these electrons lead to losses observed in long self-magnetically insulated lines.
We give a general local central limit theorem for the sum of two independent random variables, one of which satisfies a central limit theorem while the other satisfies a local central limit theorem with the same order variance. We apply this result to various quantities arising in stochastic geometry, including: size of the largest component for percolation on a box; number of components, number of edges, or number of isolated points, for random geometric graphs; covered volume for germ-grain coverage models; number of accepted points for finite-input random sequential adsorption; sum of nearest-neighbour distances for a random sample from a continuous multidimensional distribution.
This monograph gives a detailed and pedagogical account of the geometry of rigid superspace and supersymmetric Yang-Mills theories. While the core of the text is concerned with the classical theory, the quantization and anomaly problem are briefly discussed following a comprehensive introduction to BRS differential algebras and their field theoretical applications. Among the treated topics are invariant forms and vector fields on superspace, the matrix-representation of the super-Poincare group, invariant connections on reductive homogeneous spaces and the supermetric approach. Various aspects of the subject are discussed for the first time in textbook and are consistently presented in a unified geometric formalism.
The concentric circular annular duct is a common geometry in many fluid flow and heat transfer devices. For the purpose of heat transfer augmentation, fins are often employed in the annular region, and such finned ducts find wide application in compact heat exchangers (5, 6). The analysis of flow and heat transfer in this geometry is, therefore, quite important from an engineering standpoint. For fully developed conditions, the problem has already been analyzed (7-10). However, no results are available for the developing flow in the entrance region. It is with this latter problem that the present paper is concerned.
The 3-D neutronics code COREDAX has been developed based on AFEN (Analytic Function Expansion Nodal) method for x-y-z geometry and for hex-z geometry. In this study, the COREDAX code, as a regulatory review tool independent of the designer's, was applied to the SMART reactor core that was designed by KAERI (Korea Atomic Energy Research Institute). For nuclear cross section generation, the HELIOS lattice code was used in this study. The preliminary results for steady state in various conditions are presented in this paper
From autumn this year, the FRJ-2 of the Research Center Juelich will be supplying molybdenum targets to the Institut National des Radioelements in Fleurus, Belgium - which deals in medical radio-isotopes worldwide - thus helping to meet the need for technetium-99, which is used in the medical profession for diagnostic purposes because of its favourable radiological characteristics. Technetium-99 is formed as a result of the radioactive decay of molybdenum-99. For many years now, molybdenum has been produced by the irradiation of uranium in research reactors, so that the initiation of molybdenum production in the FRJ-2 is not especially new. What is unusual, however, are the particular peripheral conditions which result from the combination of the irradiation requirements, a predetermined target design and the technical characteristics of the reactor and which necessitated special solutions. This applies especially to the handling of the targets after irradiation, ...
The objective of the project was to develop an infiltration material based on SiC that should have improved corrosion resistance and should permit higher operating temperatures. From a variety of tested doping agents, zirconium silicide and molybdenum proved to be the most appropriate agents. The respective infiltration materials permit a combination of advantages of the SSiC with those of the SiSiC. Silicide SiC, analogous to the SiSiC, is almost nonshrinking, and above all is more corrosion-resistant than SiSiC in the alkaline regime, due to the replacement of free silicon by silicide phases. The operating temperature of the molybdenum-base variant is 1600 C. (orig./CB) [Deutsch] Ziel des Vorhabens war die Entwicklung eines Infiltrationswerkstoffes auf SiC-Basis mit verbesserter Korrosionsbestaendigkeit und hoeherer Einsatztemperatur. Aus einer Vielzahl von getesteten Dotierungsmoeglichkeiten kristallisierten sich Zirkondisilicid und Molybdaen als geeingete ...
Clinical information is indispensable for swift and cost-effective clarification of diseases of the larynx. While quality clarification of neurological changes in the area of the posterior cranial fossa and in the course of the vagus nerve as a cause of glottis malfunction is possible with MRI, localized disease of the larynx can more effectively be assessed with low-artifact CT. In the particularly difficult assessment of the post-operative larynx, a recurrence can be diagnosed only after a baseline study has been carried out after the end of therapy. With knowledge of the pretherapeutic findings, the findings immediately post-therapy, and the operation technique used, the optimal CT examination, which can be carried out quickly, will be able to provide more information about recurrence. (orig.) [Deutsch] Zur schnellen und kostenguenstigen Abklaerung von Erkrankungen des Larynx ist die klinische Information unabdingbar: Wenn neurologische Veraenderungen im Bereich ...
Objective: To discuss the clinical application value of dual energy subtraction (DES) in direct digital radiography of chest. Methods: 83 cases of chest digital radiography(DR) using double-energy subtraction (DES) were randomly selected, and three posterior-anterior (PA) chest films (standard image, bone image and soft tissue image) were obtained in each case, which is so called 'bone and soft tissue separated' technology. Results: With the aid of double energy subtraction (DES), the bony chest was subtracted, the sensitivity and specificity of pulmonary calcification were improved, and sensitivity of pulmonary nodes was also improved, enhancing the distinction between pulmonary benign or malignant lesions, enlightening the diagnosis of chest cage lesions, and showing a clear superiority in the detection of pulmonary nodes comparing to common chest films. The double energy subtraction (DES) films ...
Acid mine drainage represents one of the most important environmental problem facing the mining industry. If the tailings contain sulphur, acid mine drainage will be generated as soon as the tailings are exposed to oxygen. In this paper, the authors discussed a technique for the storage of acid mine drainage generating tailings that delays and even eliminates the occurrence. It was suggested that tailings should be piled by incorporating, at regular intervals, compacted waste rock. Thermal convection and diffusion will prevent oxygen from reaching the tailings, and limit water circulation. The modelling of transfer processes (heat, water, oxygen) in a well known tailings dump, the Doyon Mine, was performed, and the results compared to the modelling where compacted waste rock had been incorporated at regular intervals. The results indicated that by remaining saturated, the layers acted as capillary barriers preventing oxygen from reaching the tailings, therefore reducing significantly ...
Dual-fuel engines are modified diesel engines burning simultaneously two fuels inside the cylinder: a gaseous one, called the primary fuel and a liquid one, called the pilot fuel. The thermal efficiency of the dual-fuel engine and of the diesel engine are comparable; the level of emissions is lower compared to the diesel one. This article presents a new procedure for the combustion modeling in a LPG-diesel dual-fuel engine. The procedures deals with the ignition delay period and with the rate of heat release inside the cylinder. This procedure is validated using experimental data issued front a collaboration with the Indian Institute of Technology from Madras, India. The used engine is a single-cylinder one, air-cooled. The pilot fuel is direct injected inside the cylinder The engine was run at constant load and with different diesel substitutions, i.e. for different air to fuel ratios of the primary fuel-air mixture. The general error of the procedure is below 10%. (authors)
This document gathers the presentations given at the first French national meetings of solar energy for the development of solar systems in buildings. The meeting was organized over two days. The first day comprises 4 workshops about: urbanism and planning, cultural acceptability of solar energy in buildings (the OPAC 38 housing association, point of view on an energy information point, the Freiburg (Germany) solar region and marketing examples), technical integration to the structure (Clipsol solutions), and economical criteria (compared impacts of R and D public photovoltaic programs (USA, Japan, Germany, France, Italy), financing of rehabilitation projects, global approach of solar photovoltaic energy, technical solutions and strategy of products development, why and how to make an economical analysis of solar energy applications in the building industry). The second day comprises a plenary session and a round table: global status of solar energy development in Europe, status of ...
The preliminary study of the {sup 129}I distribution has allowed to underline the limits of use of a Homalotecium sericeum type terrestrial moss as biological indicator. However, this preliminary study allowed all the same to give a spatial distribution of this radioelement around La Hague reprocessing plant (source term) that underlines the existence of four geographic areas in function of collected activities. The levels are generally under 99 Bq/kg dry. It is recommended to improve the knowledge that we can have of transfers and quantity of iodine 129 from the marine environment to the terrestrial environment, but also, the one that we can have of factors able to modify the spatial distribution of this radionuclide. (N.C.)
The European demonstration project Hip Hip (house integrated photovoltaic high-tech in public) led the French photovoltaic market to reach a level comparable to those of the other European countries in terms of relevance of implemented solutions and costs. This document presents the best realizations and the experience gained through the Hip Hip project. Its aim is to convince the designers and managers of building projects of the advantages of photovoltaic installations integrated to the structure and connected to the power distribution grid: 1 - presentation of the technology; 2 - status of the Hip Hip demonstration project (goals, results: main innovations and impact on the French market); 3 - different possibilities of integration to the building structure; 4 - examples of projects realized in France in the framework of the Hip Hip project: integration in glass roof, frontage, added elements, fitting on roofs. (J.S.)
The deposition of platinum on various carbon blacks was carried out by forming active functional groups on the surface of the carbon support, and exchanging these active groups with different platinum complexes. Using H{sub 2}PtCl{sub 6} solution, an impregnation rather than an exchange takes place. However, using divalent platinum complexes [Pt(NH{sub 3}){sub 4}]{sup 2+}, a fast exchange takes place which leads to extremely small platinum particles highly dispersed on the surface of carbon black. A comparison of the catalytic activities of platinum supported on various carbon blacks was also carried out. The performances of PEFC (Polymer Electrolyte Fuel Cell) based on the process of the ion exchange are reported. (authors) 3 refs.
Various pollution abatement measures available to combat oil spills were reviewed with emphasis on biodegradation. Microorganisms naturally found in soils and groundwater can efficiently degrade a variety of organic contaminants. For certain sites, local temperature allows the microorganisms to reduce the contaminant concentrations without human intervention. In April 1994, a diesel fuel leak was found at a telecommunication station located in a park. The leak had already contaminated the surrounding soil. The first step of the clean-up procedure was to excavate the contaminated soil, followed by an evaluation to determine the extent of the remaining contamination. It was concluded that by using natural attenuation the deforestation of the remaining affected area could be prevented. In this instance, the natural attenuation process is expected to take five years for completion. 4 refs., 1 tab., 1 fig.
The progress made in particle detection, particularly the design of multi-detectors, like INDRA, that cover a solid angle of almost 4{pi}, have given a new impetus to heavy ion collisions. These detectors are demanding for an efficient way of selecting events that have a common history or similar features, for instance the events representing the de-excitation of a unique emitter. The problem is to find the adequate variable on which the discrimination can be based. Different methods are proposed in this work, the common point is that they require efficient models to reproduce and analyse experimental data in order to apprehend the equation of state of nuclear matter. Most of these models are based on the numerically solving of the nuclear Boltzmann equation. The application to the Ni + Ni reaction with an energy ranging from a few A.MeV to more than 50 A.MeV illustrates this work. (A.C.)
ABO{sub 3} perovskite-type oxides having vacancies in the A-sites of their structure are interesting candidates for solid electrolytes when their A-sites are occupied by Li{sup +} ions having a high mobility. This is the case with the [Li{sub 3x}La{sub 2/3-x}]TiO{sub 3} solid solution compound which has a 10{sup -3} S cm{sup -1} ionic conductivity at ambient temperature. Electrochemical intercalation in this material is possible thanks to the presence of Ti{sup 4+} but the small amount of vacancies (0.33 maximum) leads to a low intercalation rate. In order to solve this problem, the LiLaNb{sub 2}O{sub 7} material which has a greater amount of vacancies has been studied and the results relative to the electrochemical intercalation of lithium in this perovskite are presented. The thermodynamical and kinetics properties of the lithium intercalation reaction have been studied by intermittent galvano-static discharges and impedance spectroscopy in LiClO{sub 4}-propylene carbonate medium. ...
Lithium hexa-fluoro-phosphate LiPF{sub 6} is recommended for the replacement of the toxic LiAsF{sub 6} and the explosive perchlorates (like LiClO{sub 4}) in rechargeable lithium electrochemical generators. The aim of this work is to develop a new method of synthesis of this salt and to check its stability with respect to carbonated solvents: ethylene carbonate (EC), propylene carbonate (PC) and dimethyl-carbonate (DMC) in already optimized EC/DMC and PC/DMC binary mixtures. Two methods using HPF{sub 6} are proposed: the first one uses the direct neutralization of this commercial acid by LiOH in aqueous, alcoholic or acetonitrile environment, while in the second one LiPF{sub 6} is obtained from pyridinium hexa-fluoro-phosphate synthesized from HPF{sub 6} using a new and simple protocol. (J.S.) 24 refs.
The detection limit of Instrumental Neutron Activation Analysis (INAA), about a few microgram per kg, is not sufficient to determine iridium concentrations in most geological samples. Use of the coincidence counting of the 316 and 468 keV gamma-rays emitted during the decay of {sup 192}Ir, improved the sensitivity (0.01 microgram per kg). The high iridium content of the clay layers from the Cretaceous-Tertiary transition (KTB) has been considered as an evidence of the extra-terrestrial origin of the KTB mass extinction. However some results indicate that a significant part of the iridium content in sediments has a volcanic origin. Radiochemical Neutron Activation Analysis (RNAA) in some KTB samples and in basic and ultra-basic rocks show that, unlike in volcanic products, no PGE (platinoids) fractionation appears in KTB samples. The nearby chondritic PGE pattern supports an extra-terrestrial origin for the KTB iridium anomaly. 2 figs., 2 tabs., 37 refs.
Individual monitoring of personal exposure to inhalation of uranium oxides throughout the manufacture of fuel for pressurized water reactor (PWR) includes lung gamma-spectrometry, fecal analysis and urine analysis. Examination of the results shows the following: internal exposure is the consequence of repeated intake incidents as revealed by early peaks of urinary and particularly fecal elimination; a shift is often observed with the results of aerosol concentration measured through air collectors; the measured variations of uranium lung incorporations are relatively fast (apparent mean period 165 d). Correct evaluation of the effective dose equivalent from inhalation requires further information concerning the aerosol size distribution at work stations, the physico-chemical characteristics of the product leading to an estimate of its actual biological solubility, and the measurement of the fraction of aerosol liable to intake with an individual portable collector.
the development of lithium metal batteries is hindered by the bad reversibility of the Li{sup +}/Li pair, due to dendrites formation which limits the amount of active matter and can generate short-circuits. The chemical and electrochemical phenomena which take place at the electrode/organic electrolyte interface lead to the formation of a complex passivation film which is of prime importance for the functioning of this type of batteries. The in-situ infrared reflection spectroscopy is well adapted to the chemical study of the passivation layer. Two different techniques were used: the substraction normalized interfacial transform infrared spectroscopy (SNIFTIRS) and the electro-chemically modulated infrared reflectance spectroscopy. These methods have shown that the passivation layer that develops on the surface of the lithium electrode in contact with organic solutions (propylene carbonate, ethylene carbonate and dimethoxyethane) is mainly made of lithium alkyl carbonates (ROCO{sub ...
Cooperation for low carbon and energy efficient development is a high priority for France, in line with the United Nations Framework Convention on Climate Change. France contributes to tackling climate change by working with its partners on all continents to implement projects both to mitigate greenhouse gas emissions and to adapt to climate change. Within the framework of the Marrakech Accords, France also encourages the implementation of the Kyoto Protocol Clean Development Mechanism, in particular between French business and non-Annex I countries; this mechanism will facilitate the financing of mitigation projects and contribute to the sustainable development of host countries in the South. At multilateral level, France is a major donor. At a bilateral level, an initial analysis of cooperation projects which are strongly linked to tackling climate change identified public support of 136 millions euros per year, as an average over the past few years. Some project examples, mostly ...
ACRO, a NGO equipped with a laboratory to measure radioactivity, runs the Citizen Watchdog of Radioactivity in the Environment. Involving many volunteers, it monitors regularly the French coast of the Channel and many rivers of the North half of France. It also makes investigations in other places. Such an action is aimed to supplement the official monitoring, not to replace it, in order to answer to the worries of the population. This monitoring shows that some radioelements, such as iodine 129, cobalt 60, tritium, etc. released in the environment by nuclear facilities can be detected on very large areas. Carbon 14 was detected up to almost 4 times the background in vegetables around the reprocessing plant of La Hague. ACRO also sits in many official committees to transmit the point of view of the populations exposed to the radioactive pollution. It is lobbying for a decrease of the release authorization, especially for the elements that are discharged in large quantity in the ...
This article, published in issue 80 of 'l'ACROnique du nucleaire', aims to retrace the early steps in the consideration of the possibility of a nuclear accident in France, with the inclusion of 'non-institutional' participants and applying the lessons learned in Belarus in the contaminated territories around the Chernobyl nuclear power plant. After a review of the origin of the involvement of the Association pour le Controle de la Radioactivite dans l'Ouest (ACRO) in addressing post-accident issues alongside the populations living in an environment polluted by radioactivity, it discusses, from the critical viewpoint of an NGO, the context and the working method adopted for this examination. This is followed by some key elements of the programme and unresolved questions about the available body of knowledge which motivates research and about the method adopted for the work. The conclusion, moderately optimistic, ...
In the first part of the nineties many office buildings were equipped with indoor climate installations which do not meet present standards. Several options are available to improve such installations for ventilation capacity, cooling capacity, thermal comfort and air quality. One of the options concern the installation of an air conditioner in combination with heat recovery. In this article attention is paid to the renovation of the air conditioning system in the Printer house, an office building in Zwolle, Netherlands. [Dutch] Begin jaren negentig zijn veel kantoorpanden gebouwd waarvan de klimaatinstallatie tegenwoordig niet meer voldoet. De ventilatiecapaciteit is ontoereikend en koeling is mondjesmaat aanwezig, of slechts als topkoeling. Het comfort en de luchtkwaliteit zijn dan ook onder de maat. Er zijn verschillende mogelijkheden om dit te verbeteren. Plaatsing van een nieuwe luchtbehandelingskast met warmteterugwinning is daar een van. In dit artikel wordt ...
Abuzakuk T, Coward P, Shenava Y, Kumar VS, Skinner JA. The management of wounds following primary lower limb arthroplasty: a prospective, randomised study comparing hydrofibre and central pad dressings. Pris en charge des plaies apres arthroplastie primaire du member inferieur: une etude randomisee prospective comparant hydrofibre et pansements central pad La prise en charge des plaies apres arthroplastie du member inferieur n'a pas fait l'objet de recherches approfondies, essentiellement car ces plaies cicatrisent habituellement sans complications. Cependant, lorsque des implants prothetiques sont utilizes, les serieux problemes de plaies peuvent devenir desastreux. Nous rapportons les resultants d'une etude prospective, randomisee, controlee comparant un hydrofibre et un pasnement centra...
The contribution outlines the current status of the building construction projects for the German Bundestag in Berlin. The following subjects are discussed: Energetic quality of the building, energy supply concept, integrated energy supply system, electric CHP systems, cogeneration (vegetable oil), aquifer storage (heat storage, cold storage), solar energy (photovoltaic energy conversion, thermal solar energy use), economic and ecological aspects. (HW) [Deutsch] Der vorliegende Beitrag gibt einen Ueberblick ueber den aktuellen Stand des Bauvorhabens des Deutschen Bundestages in Berlin. In diesem Zusammenhang wird auf folgende Themen eingegangen: Energetische Gebaeudequalitaet, Energieversorgungskonzept, Energieverbund, stromgefuehrte BHKWs, Kraft-Waerme-Kopplung (Pflanzenoel), Aquiferspeicher (Waermespeicher, Kaeltespeicher), Sonnenergienutzung (Photovoltaik, thermische Solarenergienutzung), Wirtschaftlichkeit und Oekologie. (HW)
In the first part of the symposium, experts reviewed the state of the art of decentralized waste water treatment in Europe. In the second part, exemplary solutions in Poland and the Czech Republic were presented. The final part was dedicated to future concepts and strategies. [German] Im Herbst letzten Jahres hat die Kommunale Umwelt-AktioN U.A.N. in einer Abfolge von drei Abwasserfachsymposien Expertenrunden zum Austausch ueber den aktuellen Stand des Wissens zum Thema dezentrale Abwasserbehandlung veranstaltet. Mit dem Internationalen Symposium 'Konzepte zur Abwasserbehandlung im laendlichen Raum Europas' in Celle hat das Projekt der U.A.N. seinen Abschluss gefunden. Der Konzeption des Projektes entsprechend haben im 1. Teil des Symposiums Experten ueber den Stand der Entwicklung auf dem Sektor der dezentralen Abwasserbehandlung in Deutschland berichtet. Im 2. Teil unserer Fachtagung wurden europaeische ...
The goal of this project was to develop a new technology for preparing samples for transmission electron microscopy (TEM) on the basis of ion fine beam processing. For this purpose processes of ion-beam-assisted removal (sputtering), separation, sample handling and ion-beam-assisted chemical etching as well of system-inherent components were examined. As an alternative to a Ga-source a liquid-metal ion source based on a AuGeSi alloy was developed, characterised and used in the FIB 4400. [German] Aufgabe des Projektes war die Entwicklung einer neuen Technologie zur Probenpraeparation fuer die Transmissions-Elektronenmikroskopie (TEM) auf der Basis der Ionenfeinstrahlbearbeitung. Dazu wurden Prozesse der ionenstrahlgestuetzten Abtragung (Sputtern), der Abscheidung, des Probenhandling, des ionenstrahlgestuetzten chemischen Aetzens sowie systemeigener Komponenten untersucht. Als Alternative zur Ga-Quelle wurde eine ...
Some crops of important nutritive requirements have been collected from farmlands located in Bitsichi an old tin mining town in north central region of Nigeria. The food crops were analyzed in order to determine trace element concentrations level using Neutron Activation Analysis (NAA). The activity concentrations due to natural radionuclides in the food samples and soil samples collected within the root zone of the crops were also determined using gamma-ray spectrometry (GRS). The NAA results obtained showed higher concentration of Potassium among the essential elements in all the crops. Calcium concentration in both maize and Guinea corn was below detection limit and also Zn in Green beans, sweet potato and cassava. The trace elements; Sc, Hf, Sm, and Th, were below detection limit in all the crops except in Green beans. Rubidium (Rb) and lanthanum (La) were below detection limits only in Cabbage. The activity concentrations of the natural radionuclides in the food samples were found ...
The first working meeting of the SAPIERR project about regional final storage of radioactive waste in the European Union was held in Piestany, Slovak Republic, on February 19 and 20, 2004. SAPIERR stands for Support Action: Pilot Initiative for European Regional Repositories. This is an independent study supported financially by the European Union within the 6th Research Framework Program. The background to the project is the debate about the feasibility of regional repositories for radioactive waste in the European Union, which has come up again especially with a view to the new accession countries and the draft of a waste management directive within the framework of the Nuclear Package. The results of the SAPIERR Project will be presented in Brussels at a concluding international seminar, most probably in October 2005. The seminar will be open not only to the participating countries but also to other interested European and non-European states. (orig.) [German] Am 19. und 20. Februar ...
On account of a raised appearing of plastic waste and shreddered light fraction (SLF) from old car utilization as well as legal handicaps experiments were carried out at the Institute of Ferrous Metallurgy (RWTH Aachen) on a laboratory rig to inject DSD (Duales System Deutschland)-plastic waste and SLF with the destination of a subsequent raw material utilization in the blast furnace and cupola furnace. The experiments on the laboratory rig with DSD plastics could verify that by injection of specific coal/plastic mixtures into the blast furnace the injection rate could be raised by an improvement in the conversion degree and therefore the amount of the inserted reducing agent can be lowered. The injection of SLF without reduction of the inert materials and of the contents on alloying elements and/or tramp elements by extensive preparation has no advantages according to the experiments for the blast furnace process. Pilot experiments on the cupola furnace showed that, assuming a certain ...
The situation of natural gas in the Federal Republic of Germany is described, with particular emphasis on the advantages and consequences of natural gas supply. The brochure discusses the role of natural gas on the energy market, the reliability of natural gas supply, the environmental impacts, the energy-saving effect of natural gas, natural gas prices, the competitive strength of the German gas industry, and the long-term reliability of natural gas supply. (orig.) [German] Die Situation des Erdgases in der Bundesrepublik Deutschland wird beschrieben, wobei die wichtigsten Vorteile und Auswirkungen der Erdgasversorgung besonders hervorgehoben werden. Es geht um die Stellung des Erdgases im Energiemarkt, die Sicherheit der Energieversorgung, Umweltschutz, Energieeinsparung durch Erdgaseinsatz, Erdgaspreise, Leistungsfaehigkeit der deutschen Gaswirtschaft und um die langfristig gesicherte Erdgasversorgung. (orig.)
High energy physics is a basic research domain with a well established European and international cooperation. Cooperation can be of different type depending on the size of the facilities involved (accelerators), on their financing, and on the type of experiments that use these facilities. The CERN, the European center for nuclear research, created in October 1954, is the best example of such a cooperation. This article examines first the juridical and scientifical structure of the CERN and the mode of organization of big experiments. Then, it presents the role of international committees in the establishment of a common scientific policy in Europe and in the rest of the world. Finally, the possible future evolution of the CERN towards a worldwide project is evoked. (J.S.)
Sur l'origine des chiffres arabes A. Boucenna 1 From the pagination of an Algerian Arabic manuscript of the beginning of the 19th century,we rediscover the original shape that the Arabic numerals had before passing in Europe and underwent the transformation that gave the modern Arabic numerals. This original shape,whose use disappeared completely, proves that these numerals have their origin in the Arabic letters. Contrary to what some hypotheses pretend, particularly those that present them as drifting of Indian characters, the 10 Arabic numerals that we use are, nothing else, 10 Arabic letters more or less modified and taken in the "Abjadi" order. The hypothesis of the Indian origin of the Arabic numerals is revealed a mistake denied by the shape of the Arabic numerals and by the logic of the right to left representation of the numbers and the algorithm of the elementary operations. The Arabic numerals that simplified the writing of the numbers and the algorithms ...
In the first part of this contribution, the definition of reference values is given and the theoretical and practical problems in the application of this concept are discussed. In this connection, the present resources on instrumentation and the technical requirements for dose assessment are described. In the second part, some consequences are taken and proposals for further actions are made. (orig.) [German] Im ersten Teil des Aufsatzes werden Definitionen von Referenzwerten in der radiologischen Diagnostik untersucht und die theoretischen und praktischen Probleme der Umsetzung des gesamten Konzepts eroertert. In diesem Zusammenhang werden auch der gegenwaertige Geraetebestand und die technischen Voraussetzungen zur Dosisermittlung beschrieben. Im zweiten Teil werden daraus Schlussfolgerungen gezogen und Vorschlaege zum weiteren Vorgehen gemacht. (orig.)
In the first part of this contribution, the definition of reference values is given and the theoretical and practical problems in the application of this concept are discussed. In this connection, the present resources on instrumentation and the technical requirements for dose assessment are described. In the second part, some consequences are taken and proposals for further actions are made. (orig.) [German] Im ersten Teil des Aufsatzes werden die Definition von Referenzwerten in der radiologischen Diagnostik untersucht und die theoretischen und praktischen Probleme der Umsetzung des gesamten Konzepts eroertert. In diesem Zusammenhang werden auch der gegenwaertige Geraetebestand und die technischen Voraussetzungen zur Dosisermittlung beschrieben. Im zweiten Teil werden daraus Schlussfolgerungen gezogen und Vorschlaege zum weiteren Vorgehen gemacht. (orig.)
Apart from condensing the off-air condensers have a number of additional functions, which have been added more or less incidentally as development progressed. Advanced development of certain types of turbine condensers justifies the hope that these additional functions can be improved as power plants become cheaper and simpler.(orig.) [German] Kondensatoren haben neben ihrer Hauptaufgabe, der Kondensation des Turbinenabdampfes eine Reihe zusaetzlicher Funktionen, die sich z.T. im Laufe der Entwicklung eher beilaeufig ergeben haben. Der hohe Entwicklungsstand bei bestimmten Bauarten von Turbinenkondensatoren laesst die Erwartung zu, dass im Zuge der Vereinfachung und Verbilligung von Kraftwerksanlagen 'Nebenfunktionen' verbessert werden koennen. (orig.)
The paper describes the latest developments in STRASSY (Strategy Assistance System), the strategy assistance system for the inspection of nuclear materials. The user can now select the fuel cycle he wishes to investigate from an initial range of 19 facilities. An inspection interface has been developed to enable the details and dates of inspections to be modified. One of the special features of the application of STRASSY in international safeguards is the taking into account of timeliness of detection; certain aspects of the time manager algorithms are presented and analysed, including the guaranteed existence of a solution. The results of a study of diversion paths in a simplified cycle consisting of our facilities are presented. Finally, the modifications necessary to enable STRASSY to be used for a posterior analysis of inspection results are discussed. (authors). 7 refs., 3 figs.
Utilisation of geothermal energy may soon become an important factor in power supply in Germany. The contribution discusses the utilisation of hydrothermal low-pressure systems, the geological boundary conditions, the technical design of the thermal water cycle, and the current status of the hot dry rock technology. [German] Die Nutzung der Energie ausd Erdwaerme kann in naher Zukunft eine wichtige Rolle in der Energieversorgung Deutschlands spielen. Der vorliegende Artikel gibt einen Ueberblick ueber die Nutzung hydrothermaler Niederdrucksysteme, die geologischen Rahmenbedingungen, den technischen Aufbau des Thermalwasserkreislaufes sowie zum aktuellen Stand des Hot Dry Rock Verfahrens.
This evaluation has for object to inform about the levels in carbon 14 in the environment of the factories of La Hague. Two sectors were differentiated on one hand the terrestrial environment, and on the other hand the marine environment. The investigations concerned first and foremost food products stemming as the vegetable culture (vegetables) or individual breeding (milk, eggs) but also foodstuffs stemming from the local agriculture (cereal). In touch with the second sector, the marine environment, the sampling concerned the accessible products of the sea by all and those locally marketed (fishes, molluscs, shellfishes). The different results are presented in tables. (N.C.)
The early diagnosis of such disorders is of major importance because, in most cases, severe consequences can only be averted by early treatment. The value of magnetic resonance imaging (MRI) in many orthopaedic and traumatological conditions is generally accepted. The value of MRI in this particular field is illustrated by typical case reports on common clinical problems [Deutsch] Der Fruehdiagnose von Erkrankungen des Kindes- und Jugendalters kommt grosse Bedeutung zu, da oftmals nur durch eine daraus resultierende Fruehbehandlung schwerwiegende Folgen vermieden werden koennen. Die Kernspintomographie (Magnetresonanztomographie=MRT) ist in zahlreichen orthopaedischen-traumatologischen Fragestellungen bereits etabliert. An ausgewaehlten Fallbeispielen haeufiger klinischer Problemstellungen soll in der vorliegenden Arbeit der Stellenwert der MRT dargestellt werden. (orig.)
The aim of this work is the study of the heat transfer and of thermal behaviour of the HF (high frequency) components (in fact capacitors) of the ITER-proto-2005-FCI antenna. Preliminary results carried out with the Castem software show that it is possible to cool the hottest part of the antenna efficiently. A water flow (1 bar, 25 Celsius degrees) or an helium flow (10 bars, 50 Celsius degrees) permit to limit the maximal value of the temperature to 270 Celsius degrees. A second software Ansys has allowed the author to simulate capacitors with more complicated shapes. (A.C.)
Fur die Trennung binarer Gemische wird zunehmend das Simulated Moving Bed (SMB)-Verfahren verwendet. Fur einen storungsfreien Betrieb mussen die Volumenstrome sowie die Umschaltzeit exakt eingestellt werden. In diesem Beitrag wird mit Hilfe des Coherence-Konzepts eine Methode aufgezeigt, mit der sich die Stellgroen fur einen dispersionsfreien SMB-Prozess bestimmen lassen. Fur Langmuir- und Anti-Langmuir-Isotherme konnen einfache explizite Gleichungen bei vollstandiger Trennung angegeben werden. Das Grundprinzip dieser Methode lasst sich auch auf andere Isotherme sowie fur die unvollstandige Trennung ubertragen.
Japanese companies have developed suitable cleansing technologies and export their know-how. Some original technologies are developed today, like: in-situ chemical oxidation, iron confinement, hot-soil process, low-temperature catalytic decomposition or dechlorination of dioxins. However, some pollutions are still poorly considered (nitrates) or badly mastered (dioxins). This situation is partly due to late legal decisions and to limited pollution abatement measures. Japan is also very active in bio-cleansing research, and this, despite the lack of dialogue and directives at the national level. Several research programs with important funds have started since 1995. However, Japan is still at the preliminary stage in open-field applications of cleansing methods. (J.S.)
Trapezblechstege im Bruckenbau kommen trotz der groen Vorteile, die diese Bauweise bietet, in Deutschland bisher nur an einem Pilotprojekt zur Anwendung. Durch die charakteristischen Eigenschaften des Trapezbleches entstehen konstruktive und wirtschaftliche Vorteile gegenuber herkommlichen Bruckenbauweisen. Allerdings lassen die aktuell gultigen Regelwerke aufgrund fehlender Kenntnis zum Tragverhalten und mangelnder Erfahrung keine wirtschaftliche Ausbildung zu. Dies zeigt sich am Beispiel des Pilotprojekts. Die Ausbildung der Verbundfuge wurde hier nur sehr unbefriedigend gelost und verdeutlicht somit die Notwendigkeit einfacher und praktikabler Verbindungsmoglichkeiten. Am Institut fur Leichtbau Entwerfen und Konstruieren der Universitat Stuttgart wurde in Zusammenarbeit mit dem Institut...
A calculation program (URA 6.F4) was elaborated on FORTRAN IV language, that through finite differences solves the unidimensional scalar Helmholtz equation, assuming only one energy group, in spherical cylindrical or plane geometry. The purpose is the determination of the flow distribution in a reactor of spherical cylindrical or plane geometry and the critical dimensions. Feeding as entrance datas to the program the geometry, diffusion coefficients and macroscopic transversals cross sections of absorption and fission for each region. The differential diffusion equation is converted with its boundary conditions, to one system of homogeneous algebraic linear equations using the box integration technique. The investigation on criticality is converted then in a succession of eigenvalue problems for the critical eigenvalue. In general, only is necessary to solve the first eigenvalue and its corresponding eigenvector, employing ...
In dissipative ordinary differential equation systems different time scales cause anisotropic phase volume contraction along solution trajectories. Model reduction methods exploit this for simplifying chemical kinetics via a time scale separation into fast and slow modes. The aim is to approximate the system dynamics with a dimension-reduced model after eliminating the fast modes by enslaving them to the slow ones via computation of a slow attracting manifold. We present a novel method for computing approximations of such manifolds using trajectory-based optimization. We discuss Riemannian geometry concepts as a basis for suitable optimization criteria characterizing trajectories near slow attracting manifolds and thus provide insight into fundamental geometric properties of multiple time scale chemical kinetics. The optimization criteria correspond to a suitable mathematical formulation of "minimal relaxation" of chemical forces along reaction trajectories under ...
The design of a gaging head for a portable radionuclide X-ray fluorescence analyzer is described. The gaging head is designed as a construction unit system which enables the application of lateral reflexion geometry as well as of coaxial geometry. It is designed so that adjustment from one geometry to the other is labour and time saving. The selection of characteristic radiation is performed by a couple of Ross' differential filters. These filters are prepared by a novel technique developed by our laboratory. The filter exchange is effected by the longitudinal move of the couple of filters encapsulated in a holder. The shift of the filters is controlled by means of a triggering mechanism situated in the body of the gaging head handle. This design makes is possible to handle the gaging head during measurements with one hand. A simple interchange of the absorption filter for the transmissive filter allows the operator to ...
It is very well known that the CANDU reactor has positive Coolant Void Reactivity (CVR), which is most important criticisms about CANDU. The most recent innovations based on using a thin absorbent Hafnium shell in the central bundle element were successfully been applied to the Advanced CANDU Reactor (ACR) project. The paper's objective is to analyze elementary lattice cell effects in applying such methods to reduce the CVR. Three basic fuel designs in their corresponding geometries were chosen to be compared: the ACR-1000TM, the RU-43 (developed in INR Pitesti) and the standard CANDU fuel. The bundle geometry influence on void effect was also evaluated. The WIMS calculations proved the Hafnium absorber suitability (in the latest 'shell design') to achieve the negative CVR target with great accuracy for the ACR-1000 fuel bundle design than for the other two projects. (authors)
The calculation of nominal choke valve size determines the effective capacity for an oil and gas production system. The degree of restriction for the controlling area in the valve is a function of the surrounding geometry. In an orifice plate this is known as the 'velocity of approach' and can be used to determine the meter coefficient (C_m). This paper presents a technique for choke valves, based on the meter velocity of approach parameter, which can be used to predict the Valve Coefficient (C_v) for new trim designs. The prediction method uses a data trend based on a number of flow tests conducted on various trim characteristics. The resultant parametric equation is used to predict the C_v of a new trim geometry. The method relies on experimental data determined per IEC 60534-2-3, with calculations per IEC 60534-2-1. This paper further investigates the effect of varying upstream geometry on C_v for a 4'' nominal valve.
As a three-year joint university-industry effort, development of a generalized boiling transition analysis method has been started in 2002 aiming at enhanced capabilities of subchannel analysis for a wide variety of BWR-type fuel bundle geometry from ordinary BWR to tight lattice fuel bundles. For this purpose, five dominant factors affecting boiling transition phenomena have been identified on which our efforts of experimentation and numerical analyses are focused. In this report, as the first-year achievement, we will describe a master plan of the development and contents for experimental approaches to construct thermal-hydraulic databases. The databases will be utilized for the developments of constitutive equations to describe the basic characteristics of the elementary processes. The planned experiments are divided into two groups. One is air-water experiments at atmospheric pressure, and the other is steam-water experiments up to 1 MPa. The former group of ...
As a three-year joint university-industry effort, development of a generalized boiling transition analysis method has been started in 2002 aiming at enhanced capabilities of subchannel analysis for a wide variety of BWR-type fuel bundle geometry from ordinary BWR to tight lattice fuel bundles. For this purpose, five dominant factors affecting boiling transition phenomena have been identified on which our efforts of experimentation and numerical analyses are focused. In this report, as the first-year achievement, we will describe a master plan of the development and contents for experimental approaches to construct thermal-hydraulic databases. The databases will be utilized for the developments of constitutive equations to describe the basic characteristics of the elementary processes. The planned experiments are divided into two groups. One is air-water experiments at atmospheric pressure, and the other is steam-water experiments up to 1 MPa. The former group of ...
A whole sequence of the parameters of the combined heat and power system (KWK) is described which enables a comparison between the electricity and heat demand of a consumer and the energy availability through a combined heat and power system. Proceeding from this, a thermodynamic model of a steam and gas process with combined heat and power is introduced which is based on an exergetic balancing of the subsystems of the process. In this way, the varying thermodynamic quality of the energy flows occuring in the process will be taken into consideration so that the results of the model correspond in any case with the second law of thermodynamics. (orig.) [Deutsch] Es wird ein vollstaendiger Satz von Kenngroessen der Kraft-Waerme-Kopplung (KWK) beschrieben, mit dessen Hilfe der Strom- und Waermebedarf eines Verbrauchers mit der Energiebereitstellung durch eine KWK-Anlage verglichen werden kann. Darauf aufbauend wird ein thermodynamisches Modell des GuD-Prozesses mit ...
'Within 15 years the energy consumption bottleneck has shifted from the supply side to emissions, i.e. to the waste side.' Reflecting this statement one may realize the importance of lending more weight to energy conservation but may also be induced to critically analyze the corresponding measures. First results of such reflections are given with regard to the payback periods of air pollution abatement measures relative to the additional emissions they cause. (orig.).
The design changes of the improved 2,5 l direct injection Diesel engine with the nominal power output of 52 kW and a maximum torque of 143 Nm are described. This engine which is installed in the Ford Transit meets all relevant exhaust emission standards that are presently in effect. (orig.).
This publication of the Areva Group, a world nuclear industry leader, provides information on the energy in many domains. This issue deals with the nuclear fuel cycle, the biofuels, the everyday geothermal power, the Unites States energy supply and types, the Bertrand Picard solar aircraft, the kyoto protocol and the wind power leaders. A special chapter is devoted to the renaissance of solar homes. (A.L.B.)
The petroleum and petroleum products increase offer a real development opportunity to the alternative fuels. In the context of the french energy accounting increase, the energy independence notion incites the government to promote these new fuels. If the LPG seems declining because of the accident risks fear, the fuel cell is not for today. Near these two sectors what is the future of the biofuels and the natural gas vehicle or the electric cars? (A.L.B.)
Background and ObjectivesClopidogrel resistance or low-responsiveness may be associated with recurrent atherothrombotic events after drug-eluting stent (DES) implantation. We prospectively...Full Text Available
The preliminary results of a feasibility study of nighttime and/or daytime accelerated ventilation for reducing or even avoiding air conditioning energy consumption in commercial buildings, is presented. The first part of the study is based on computerized simulations and in-situ experimentations which are described. The second part is aimed at determining technological limitations to the various components and optimizing building environmental quality in terms of energy conservation, acoustics and air quality
This paper deals with the control of an electromechanical valves engine. The control uses neural networks in order to build a non-linear model of engine filing which depends on the driven inlets. The aim is to build this real-time model and to integrate this model to a control system which performs an iterative inversion. (J.S.)
This study was aimed to test and select hydrophobic activated charcoal, manufactured in Romania, used as adsorbents of solvents which partly compose diluters employed in car industry. With regard to the diluters, three of the seven types of activated charcoal studied (Sorbent 1, R - Cafs and AD3) showed the greatest capacity of adsorption, when determined under dynamic and static conditions. (authors) 8 refs.
This paper reviews the mill flowsheet applied at the SOMAIR (Societe des Mines de l'Air) uranium mill in Niger. It focuses on the yellow cake quality improvements achieved by molybdenum and zirconium elimination through double yellow cake precipitation in tanks at first stage and through size/density control in a fluidized bed precipitator at second stage. Water saving aspects in the plant are also presented. (author)
An important opportunity for solving future traffic problems lies in a change of the connection existing between traffic growth and economic development. It could help bring about a cut in traffic intensity. This can be achieved by rationalizing transport processes, i.e. by enhancing the efficiency of traffic via improved organization and infrastructure. Rationalization means that a given traffic effort (distance in kilometres, time, route, energy) can yield a higher transport effect, or a certain transport effect can be attained with less traffic effort. Enhanced productivity permits more transport without more traffic-related and environmental nuisances. (orig.) [Deutsch] Ein wichtiger Weg zur Loesung der kuenftigen Verkehrsprobleme liegt in der Veraenderung des Zusammenhangs der zwischen Verkehrswachstum und Wirtschaftsentwicklung besteht. Damit koennte eine Senkung der Transportintensitaet erreicht werden. Ein Ansatz hierzu bietet die Rationalisierung der ...
The work of the study group for coal conversion by hydrogenation (G.E.C.H.) is an example of well concerted association between research laboratories (CNRS, Ecole des Mines...) and directly interested industrial research centers, (CERCHAR, G d F, IFP). This paper presents the activities of G.E.C.H. in the field of coal conversion by hydroliquefaction.
The position paper will provide the basis for further strategies on offshore wind power development in consideration of ecological and conservation aspects. [German] Das Positionspapier des Bundesministeriums fuer Umwelt, Naturschutz und Reaktorsicherheit (BMU) einschliesslich des Umweltbundesamtes (UBA) und des Bundesamtes fuer Naturschutz (BfN) ist Ergebnis der Arbeiten der BMU-Projektgruppe 'Windenergienutzung im Offshore-Bereich im Hinblick auf die BMU-Anliegen'. Es beschreibt den derzeitigen Stand einer Strategie zur umwelt- und naturvertraeglichen Erschliessung der Windenergienutzung auf See (Offshore). Es bildet die Grundlage fuer die Weiterentwicklung dieser Strategie und dabei insbesondere zur Abstimmung mit den Anliegen anderer Bundesressorts und den Kuestenlaendern, sowie zur intensiveren Einbeziehung beteiligter Verbaende und Fachkreise. Vor dem Hintergrund der zur Genehmigung eingereichten ...
The neutron detector is cased in a metal envelop and has one detector with a very sensitive fission chamber and a second detector with a fission chamber less sensitive that the first one and a boron coated ionisation chamber for reducing gamma radiation detection.
French ... Title Synthese d'agregats metalliques par radiolyse de solutions aqueuses de sels simples ou complexes. Etude par M. E. du greffage des agregats sur membranes de carbone.
Zusammenfassung Der vom Bundesamt f?r Sicherheit in der Informationstechnik (BSI) entwickelte Ansatz des IT-Grundschutzes war bereits Gegenstand von Beitr?gen in der DuD. Inzwischen hat das ?Grundschutzhandbuch? Eingang in die internationale Standard-Familie ISO 2700x gefunden. Der Autor berichtet ?ber die Erfahrungen mit den ersten durchgef?hrten Zertifizierungen nach dem neuen ISO-Standard auf der Basis von IT-Grundschutz.
Some 43 papers were presented in 4 sections: Organ and bud culture of tree species (24 papers); Cell suspension and callus culture of tree species (11); Culture of haploid tissue of tree species and production of wood homozygotes (3); and Isolation, culture and somatic fusion of protoplasts as a means of somatic hybridization and genetic engineering (5).
The Conference on Building Design and Architecture organized by Swedish Council for Building Research Contents included articles on building physics, thermal-climate technology, and building location and planning.
Climate change is not only dangerous but also expensive. On the other hand, air pollution abatement measures are costly as well. Scientists of the Microeconomics Department investigated how air pollution abatement and cost efficiency can best be combined. (orig.)
The device is made by a tool at the end of a flexible cable, a motor for the rotation of the flexible, a linear drive with a guide for it between the winder and the tube.
The results of the creep performance studies at temperatures from 700-1000 C with welds of alloy 800 HT, the manual shielded metal arc welds made with Githerm 85 and Grini 209 filler metals, as well as the MIG pulsed arc welds made with the Nicrofer S 206 and Nicrofer S 5520 filler metals, proved to be in very good agreement with the calculated characteristic values published on VdTUeV sheet 434 in comparative assessments based on creep values valid for a service period of 10 000 hours. The MIG pulsed arc weld made with the Nicrofer S 5520 filler metal achieved by far the best results and strength values comparable to those of the base material, whereas the values of the other welds were corresponding to calculated strength values of the base material reduced by 20%. (orig./CB) [Deutsch] Die im Temperaturbereich von 700-1000 C an Alloy 800 HT und den Elektrodenhandschweissverbindungen mit den Schweisszusaetzen Gritherm 85 und Grini 209, sowie den MIG-Pulsed-Arc-Schweissungen mit den ...
In the last issue of 'L'Industrie ceramique et verriere', we presented the first part of this study. We describe in this issue the experimental procedure, the results and the conclusions of this work. (authors)
The author cites the example of Gelsenkirchen in order to illustrate the measures taken in the field of power supply with regard to air pollution abatement. (orig.) [Deutsch] Der Verfasser gibt am Beispiel der Stadt Gelsenkirchen einen Ueberblick darueber, was hinsichtlich des Klimaschutzes - und zwar bezogen auf die Energieversorgung - in den letzten Jahren in Gelsenkirchen getan wurde. (orig.)
Austenitic stainless steel (18% Cr, 12% Ni, Mo gradation between 0,06 to 3,6%) had been solution nitrided. By step-by-step removing, the samples could be prepared with various surface contents of nitrogen from 0.04 to 0.42%. In two test series the influence of nitrogen had been determined. The susceptibility against pitting corrosion of these samples had been tested by the chronopotentiostatical method. For the investigated steel composition and the used corrosion system there is no influence of molybdenum on the effectiveness of nitrogen. The effectiveness of nitrogen can be described by the factor 25 in the PRE. By the investigation of the surfaces with the XPS analysis, it could be shown that the passivation and the pit nucleation is influenced by nitrogen. In these ranges NO{sub x}, NH{sub x}, and NH{sub z}-spectra have been detected. Bound Mo was found in steels containing molybdenum. It is assumed that the repassivation mechanisms of N and Mo work independently of each other. ...
Based on the CFD-code FLUENT trademark, theoretical studies were conducted of the influences of incineration chamber geometry (direct, countercurrent and center flow) on the combustion process. The boundary conditions, e.g., the thermal input and the waste grate, were kept constant. Close attention was paid to the distribution of flow, spe-cies, and temperatures. In addition, the influence of a dis-placement body at the end of the combustion chamber was tested. The variation of different wall materials and the prediction of problem areas concerning corrosion, slagging, and contamination completed the studies. Close to the chamber walls, high CO-concentrations may indi-cate corrosion; particle flow may indicate where contami-nation, slagging or erosion could occur. (orig.)
The influence of bowl offset on motored mean flow and turbulence in a direct injection diesel engine has been examined with the aid of a multi-dimensional flow code. Results are presented for three piston geometries. The bowl geometry of each piston was the same, while the offset between the bowl and the cylinder axis was varied from 0.0 to 9.6% of the bore. The swirl ratio at intake valve closing was also varied from 2.60 to 4.27. It was found that the angular momentum of the air at TDC was decreased by less than 8% when the bowl was offset. Nevertheless, the mean (squish and swirl) flows were strongly affected by the offset. In addition, the distribution of turbulent kinetic energy (predicted by the /delta/-e model) was modified. Moderate increases (10% or less) in mass averaged turbulence intensity at TDC with offset were observed.
For the determination of the thermal-hydraulic performances of rough surfaces, the method of evaluation is particularly important. In order to increase confidence in the results, a new evaluation procedure was introduced. This procedure is based on the transformation of simple channel experimental results to equal boundary conditions, and on the suitable application and confirmation of these transformed values in more complicated flow channel geometries. Existing methods, applied to the results obtained in an annular channel, do not fulfil all the transformation requirements. Thus a new, more complete transformation method, which uses the turbulent eddy diffusivity model, was developed. To check the quality of this transformation, within the scope of the new evaluation procedure, the results of experimental investigation in annular channels and in a bundle of hexagonal geometry were used together with the predictions of benchmark calculations. ...
Results of ongoing research project at the McMaster Nuclear Reactor Facility on real-time neutron radiography for the visualization of interfacial geometry, movements and phase distributions in gas-liquid and gas-liquid-metal multi-phase flows are presented. Experiments were conducted with bubble column tubes with boiling liquid nitrogen, air-water and air-mercury mixtures. Discussions are also focused on air-water flowing within a tube containing a CANDU type 37 rod fuel bundle assembly positioned both horizontally and vertically. Computer processing using a digital image format to enhance the real-time images was used. Imaging techniques include frame averaging, background substraction, edge enhancement (spatial filtering), contrast enhancement and video densitometry. (orig.).
A cold-leg small-break loss-of-coolant accident (SBLOCA) experiment was performed on the PACTEL facility to study the behavior of natural circulation in a VVER-440 reactor geometry. The facility is a volumetrically scaled (1:305) integral test loop simulating the VVER-440 reactors used in Finland. The test results were used to assess the computer codes RELAP5/MOD3.1 and APROS 3.0 for VVER reactors. The behavior of the horizontal steam generator and the effect of the hot-leg loop seal were of particular interest. The specific parameters to be compared included the primary pressure and the downcomer mass flow rate.
A cold-leg small-break loss-of-coolant accident (SBLOCA) experiment was performed on the PACTEL facility to study the behavior of natural circulation in a VVER-440 reactor geometry. The facility is a volumetrically scaled (1:305) integral test loop simulating the VVER-440 reactors used in Finland. The test results were used to assess the computer codes RELAP5/MOD3.1 and APROS 3.0 for VVER reactors. The behavior of the horizontal steam generator and the effect of the hot-leg loop seal were of particular interest. The specific parameters to be compared included the primary pressure and the downcomer mass flow rate.
Abstract In this paper, a new predictive model that can forecast the performance of a vertical axis wind turbine (VAWT) is presented. The new model includes four primary variables (rotor velocity, wind velocity, air density, and turbine power output) as well as five geometrical variables (rotor radius, turbine height, turbine width, stator spacing, and stator angle). These variables are reduced to include the power coefficient (Cp) and tip speed ratio (TSR). A power coefficient correlation for a novel VAWT (called a Zephyr Vertical axis Wind Turbine (ZVWT)) is developed. The turbine is an adaptation of the Savonius design. The new correlation can predict the turbine's performance for altered stator geometry and varying operating conditions. Numerical simulations with a rotating reference f...
The authors consider the dynamics of interacting elastic disks in the plane. This is an experimentally realizable two-dimensional model of dry granular flow where the stresses can be visualized using the photoelastic effect. As the elastic disks move in a vacuum, they interact through collisions with each other and with the surrounding geometry. Because of the finite propagation speed of deformations inside each grain it can be difficult to capture computationally even simple experiments involving just a few interacting grains. The goal of this project is to improve our ability to simulate dense granular flow in complex geometry. They begin this process by reviewing some past work, how they can improve upon previous work. the focus of this project is on capturing the elastic dynamics of each grain in an approximate, computationally tractable, model that can be coupled to a molecular dynamics scheme.
Details of the interaction of photons with tissue phantoms are elucidated using Monte Carlo simulations. In particular, photon sampling volumes and photon pathlengths are determined for a variety of scattering and absorption parameters. The Monte Carlo simulations are specifically designed to model light delivery and collection geometries relevant to clinical applications of optical biopsy techniques. The Monte Carlo simulations assume that light is delivered and collected by two, nearly-adjacent optical fibers and take into account the numerical aperture of the fibers as well as reflectance and refraction at interfaces between different media. To determine the validity of the Monte Carlo simulations for modeling the interactions between the photons and the tissue phantom in these geometries, the simulations were compared to measurements of aqueous suspensions of polystyrene microspheres in the wavelength range 450-750 nm.
In the frame of the Primary Wall Module prototype manufacturing for ITER, a consistent R and D phase was conducted in order to identify the industrial allowable tolerances and manufacturing problems which would occur when joining pieces by HIPping process during the PW module manufacturing. The purpose of this development was to give as industrial as possible manufacturing routes for joining together large Stainless Steel or DS-Copper pieces with Stainless Steel tubes and for bonding Beryllium tiles onto a curved component surface. The study concerned surface preparations, allowable gaps and joint geometry, Beryllium tile geometry, Titanium interlayer thickness, etc. This R and D phase also allowed the development and validation of different ultrasonic inspection tools needed for plate-plate, tube-plate, edge to edge plate bonding.
Data are presented on the continuous-wave (cw), room-temperature (300 K) operation of stripe-geometry In{sub 0.5}(Al{sub {ital x}}Ga{sub 1{minus}{ital x}}){sub 0.5}P quantum-well heterostructure lasers defined via hydrogenation. Passivation of the Zn acceptors in the cap and upper confining layer provides gain guiding, and elimination of the current-blocking oxide reduces the thermal impedance. The resultant device is capable of better performance than conventional oxide-stripe diodes fabricated on the same material.
Data are presented on the continuous-wave (cw), room-temperature (300 K) operation of stripe-geometry In{sub 0.5}(Al{sub {ital x}}Ga{sub 1{minus}{ital x}}){sub 0.5}P quantum-well heterostructure lasers defined via hydrogenation. Passivation of the Zn acceptors in the cap and upper confining layer provides gain guiding, and elimination of the current-blocking oxide reduces the thermal impedance. The resultant device is capable of better performance than conventional oxide-stripe diodes fabricated on the same material.
The effects of group structures and weighting functions on neutron penetration through a thick Na-Fe geometry are studied. The recommended broad-group (61-neutron/23-gamma-ray) and few-group (22-neutron/10-gamma-ray) structures are tailored to the sodium and iron resonances, windows, and capture gamma-ray spectra. The best weighting functions are shown to be fine-group fluxes selected from a few key locations in the geometry. These group structures and weighting functions, relative to existing group structures and conventional weighting functions, improve the accuracy of the computed 61-neutron-group Bonner ball responses by up to one hundred percent and of the computed 22-neutron-group results by up to six hundred percent.
One of the salient features of human perception is its invariance under dilatation in addition to the Euclidean group, but its non-invariance under special conformal transformation. We investigate a holographic approach to the information processing in image discrimination with this feature. We claim that a strongly coupled analogue of the statistical model proposed by Bialek and Zee can be holographically realized in scale invariant but non-conformal Euclidean geometries. We identify the Bayesian probability distribution of our generalized Bialek-Zee model with the GKPW partition function of the dual gravitational system. We provide a concrete example of the geometric configuration based on a vector condensation model coupled with the Euclidean Einstein-Hilbert action. From the proposed geometry, we study sample correlation functions to compute the Bayesian probability distribution.
The nucleation and propagation of hydrofractures by injection of over pressured fluids in an elastic and isotropic medium are studied experimentally. Non-Newtonian fluids are injected inside a gelatine whose mechanical properties are assumed isotropic at the experimental strain rates. Linear elastic theory predicts that plastic deformation associated to breakage of gelatin bonds is limited to a small zone ahead of the tip of the propagating fracture and that propagation will be maintained while the fluid pressure exceeds the normal stress to the fracture walls (Ch\\'avez-\\'Alvarez,2008) (i.e., the minimum compressive stress), resulting in a single mode I fracture geometry. However, we observed the propagation of fractures type II and III as well as nucleation of secondary fractures, with oblique to perpendicular trajectories with respect to the initial fracture. In the Video (http://hdl.handle.net/1813/14122) experimental evidence shows that the fracture shape ...
The dynamic response of cylindrical and ring-shaped YBaCuO bulk parts to pulsed magnetic fields is calculated by using small sets of finite elements. Some comparisons with experimental results are provided, and they give confidence in the modelling of the superconducting properties. Transient magnetizations as a function of time and space as well as shapes and absolute values of trapped magnetic flux profiles are presented. The influence of the sample geometry is investigated for different millisecond pulsed magnetization processes. Results are reported for different radial thicknesses and heights, different pulse durations, peak magnetic fields and pulse sequences with and without stepwise cooling. Comparisons concerning the achievable trapped magnetic field and flux are made, and implications for the use of high-temperature superconductor bulk parts as cryo-permanent magnets in potential applications like electric machinery are discussed.
The so-called spectral dimension is a scale-dependent number associated with both geometries and field theories that has recently attracted much attention, driven largely though not exclusively by investigations of causal dynamical triangulations (CDT) and Horava gravity as possible candidates for quantum gravity. We advocate the use of the spectral dimension as a probe for the kinematics of these (and other) systems in the region where spacetime curvature is small, and the manifold is flat to a good approximation. In particular, we show how to assign a spectral dimension (as a function of so-called diffusion time) to any arbitrarily specified dispersion relation. We also analyze the fundamental properties of spectral dimension using extensions of the usual Seeley-DeWitt and Feynman expansions, and by saddle point techniques. The spectral dimension turns out to be a useful, robust and powerful probe, not only of geometry, but also of ...
Reduction of the metallic impurity concentration in the TCA plasma has enabled us to correlate the observed heating with the calculated position where the rf energy is deposited. In modelling the measured antenna loading due to the presence of Alfven resonance surfaces, and hence inferring the energy deposition profile, both ion cyclotron effects and the toroidal geometry must be considered. In particular, toroidicity couples energy to resonance surfaces that would not be excited in cylindrical geometry. The increase in electron density during a rf pulse changes the positions of these surfaces so that spectrum-related effects may be observed. The appearance of a new surface at the centre of the plasma is seen as a sharp discontinuity on many of the macroscopic parameters, accompanied by evidence of changes in the current density profile. These results, and the predictions of numerical codes, have imposed new constraints on the optimisation of ...
Off-axis electron holography is used to characterize a linear array of transistors, which was prepared for examination in cross-sectional geometry in the transmission electron microscope (TEM) using focused ion beam (FIB) milling from the substrate side of the semiconductor device. The measured electrostatic potential is compared with results obtained from TEM specimens prepared using the more conventional 'trench' FIB geometry. The use of carbon coating to remove specimen charging effects, which result in electrostatic fringing fields outside 'trench' specimens, is demonstrated. Such fringing fields are not observed after milling from the substrate side of the device. Analysis of the measured holographic phase images suggests that the electrically inactive layer on the surface of each FIB-milled specimen typically has a thickness of 100 nm.
A conformational analysis of ethyl azidoformate (EAF) has been carried out by the MINDO/3 quantum-chemical method. It has been shown that EAF exists in the form of two conformers differing with respect to rotation around the C-N bond. Complete optimization of the geometry has been carried out for both conformers. It has been found that the transoid conformation is planar and that the cisoid conformation is nonplanar. The height of the rotation barrier is 15.4 kcal/mole. The optimal geometry of the transition state has been calculated. It has been noted that a significant role in the mechanism of the conformational transition is played by the inversion of a nitrogen, which facilitates the transition. The results of the calculation have been confirmed by IR-spectroscopic data.
This paper deals with surface defects of automobile outer panels, which alter significantly the vehicle quality. Such defects occur during springback, after forming or flanging steps, and are characterized by concave depression of small amplitude over the convex shape of the part. The aim of this work is to reproduce at the laboratory scale a surface defect that occurs after flanging on a geometry similar to a door upper corner. A dedicated device has been designed in order to generate small size surface defects during flanging of metallic thin sheets. The outer surface of the sample was digitalized and the spatial geometry of the defect was evaluated from curvature change along 2D profiles. This study shows that the flanging height does not influence significantly the surface defect geome...
We extend a previous result [Phys. Rev. Lett. 105, 090403 (2010)] on Casimir repulsion between a plate with a hole and a cylinder centered above it to geometries in which the central object can no longer be treated as a point dipole. We show through numerical calculations that as the distance between the plate and central object decreases, there is an intermediate regime in which the repulsive force increases dramatically. Beyond this, the force rapidly switches over to attraction as the separation decreases further to zero, in line with the proximity force approximation. We demonstrate that this effect can be understood as a competition between an increased repulsion due to a larger polarizability of the central object interacting with increased fringing fields near the edge of the plate, and attractive forces due primarily to the nonzero thickness of the plate. In comparison with our previous work, we find that using the same plate geometry ...
A nodal integral method is derived for the monoenergetic, steady-state, fixed source neutron diffusion equation in hexagonal geometry based on a coordinate transformation that maps a parallelogram into a rectangle. The new hexagonal nodal diffusion method is implemented in the computer code HND where the discrete-variable equations are solved via an iterative scheme. Because the new method's equations are derived for a rhombus, they can be solved on a sequence of embedded meshes to study the method's error order. Indeed a preliminary numerical error analysis reveals a second-order error in the mesh size, and comparison with finite difference results obtained with the finite difference based BOLD-VENTURE code indicate the superior accuracy of our new nodal method.
In order to study nuclear criticality safety related to the development of fast breeder technology, /sup 252/Cf-source-driven neutron noise analysis measurements were performed with a Pu-U nitrate solution in a slab tank of various heights and thickness varying 11.43 cm to 19.05 cm. The results and conclusions of these experiments are (1) a capability to measure the subcriticality of a multiplying system of slab geometry to a k/sub eff/ as low as 0.7 was demonstrated, (2) calculated neutron multiplication factors agreed with those from the experiments within approx.0.02, and (3) the applicability of the method for plutonium solution systems was demonstrated. This paper describes measurements in which the height of the slab was varied for a fixed thickness and the thickness varied for a fixed height, which are the first applications of this measurement method to slab geometry.
Purpose: For planning the therapeutic strategies and estimating the prognosis in esophageal cancer, N-staging is very important. To date, MRI still is of minor importance as imaging modality of the mediastinum despite promising developments in the past, like ECG-gating or 'averaging' sequences, e.g. LOTA (Long-term averaging), which facilitate mediastinal and thoracic MR-imaging. In a prospective approach, the value of MRI based N-staging was examined with respect to LOTA-sequences. Material and Methods: Within from weeks prior to esophagectomy, standardized MRI of the esophagus was performed in 15 patients (10 squamous-cell-carcinomas and 5 adenocarcinomas) using a 1.5 T whole body scanner. Imaging quality was classified based on depiction of aortic wall or tracheal wall layers. Criteria for malignant infiltration were a diameter of more than 15 mm or a round appearance of a lymph node together with GD-DTPA enhancement. All data were blinded and separately read by ...
Tumours lesions of the temporal bone and of the cerebello-pontine angle are rare.This tumours can be separated into benign and malignant lesions. In this paper the CT and MRI characteristica of tumours of the temporal bone and the cerebello-pontane angle will be demonstrated. High resolution CT (HRCT) as usually performed in the axial plane are using a high resolution bone window level setting, coronal planes are the reconstructed from the axial data set or will be obtained directly. With the MRI FLAIR sequence in the axial plane the whole brain will be scanned either to depict or exclude a tumour invasion into the brain. After this,T2-weighted fast spin echo sequences or fatsuppressed inversion recovery sequences in high resolution technique in the axial plane will be obtained from the temporal bone and axial T1-weighted spinecho sequences before and after the intravenous application of contrast material will be obtained of this region. Finally T1-weighted spinecho sequences in high ...
The K alpha / K beta ratio of Mn KX-rays scattered by metallic samples changed remarkably with the geometry between the sample and the (55)Fe source-Si(Li) detector system. On the contrary, this intensity ratio changed little in the cases of non-metallic scatterer samples such as lucite or mylar. This difference is interpreted as due to the occurrence of strong or weak interference in the coherent scattering photons. PMID:7280291
An irradiation head with sample holders is described and measurement geometry is reported. Measurements were made for optimizing the distance between the source and the sample and for optimizing the sample diameter. The optimal distance between the source and the sample does not depend on the collimator diameter. The sample diameter should not exceed 30 - 35 mm. Sensitivity and detection limits were determined for Zn, Pb and Br and calibration curves were plotted. (M.D.) 6 figs., 2 tabs., 4 refs.
Simulation of the skim-off method for radon measurement by activated charcoal has been carried out by the finite elements method. The variation of radon concentration with peak appearance has been simulated. The thickness of the layer of charcoal removed after exposure and the time of peak appearance have been varied. For the charcoal and canister geometry used, the best results were found when the thickness of the layer removed was 1.72 mm.
We demonstrate the existence of shear-free cosmological models with rotation and expansion which support inflationary scenarios. The corresponding metrics belong to the family of spatially homogeneous models with the geometry of the closed universe (Bianchi type IX). We show that the global vorticity does not prevent inflation and can even accelerate it.
We attempt to reformulate eleven dimensional supergravity in terms of an object that unifies the three-form and the metric and makes the M-theory duality group manifest. This short note deals with the case of where the U-duality group SO(5,5) acts in five spatial dimensions.
The feasibility was studied of the application of radionuclide X-ray fluorescence analysis to the identification and determination of chemical elements in the air. A description of the method is presented, the main stages of the analysis are discussed (sample preparation and standards, selection of radioactive radiation sources, geometry of measurement and evaluation of results). The method is illustrated on the determination of elements Fe, Cu, Zn, Br, and Pb in air samples taken in the city of Prague. (author) 2 tabs., 2 figs., 14 refs.
Any transport of nuclear material is associated with the risk of contamination after release into working areas or environment. stationary installed safe geometry vessels with pneumatic transfer between them offer unique safety features and reduce operating costs. The article describes the case of HTR fuel spheres, where a specially designed conveying system has been developed and the prototype conveyor has been tested.
The seawater in the intake structure flows into the large pump to with draw excess heat from the turbine steam condenser. In the intake structure of a nuclear power plant, undesirable pump operating characteristics such as vortices, impeller damages and non-uniform pump-approach flow around the pump bells take place frequently due to poorly-arranged intake geometry. In this study, physical modeling test was performed to predict the hydraulic phenomenon, and proposed flow control devices.
The success of the Randall-Sundrum scenario relies on stabilization of the modulus field or the radion, which is the scalar field about the background geometry. The stabilization mechanism proposed by Goldberger and Wise has the consequence that this radion is lighter than the graviton Kaluza-Klein states so that the first particle to be discovered is the radion. In this work, we study in detail the decay, production, and detection of the radion at hadronic, e{sup +}e{sup -}, and {gamma}{gamma} colliders.
A large Bragg-curve spectrometer has been constructed and tested. The detector has a cylindrical geometry and operates with a homogeneous electric field. Energy resolutions of <0.8% and Z resolutions of Z/..delta..Z=80 have been achieved for eleastically scattered /sup 58/Ni ions. These results demonstrate the suitability of this large solid-angle detector for use in a wide variety of heavy-ion scattering experiments.
A large Bragg-curve spectrometer has been constructed and tested. The detector has a cylindrical geometry and operates with a homogeneous electric field. Energy resolutions of <0.8% and Z resolutions of Z/#DELTA#Z=80 have been achieved for eleastically scattered "5"8Ni ions. These results demonstrate the suitability of this large solid-angle detector for use in a wide variety of heavy-ion scattering experiments. (orig.).
One-velocity angular flux of a neutron field generated by a polarly anisotropic point source in an infinite homogeneous region is calculated in P3 approximation, using the spherical harmonics operator formalism adapted to two-dimensional spherical geometry. The problem is reduced to simple algebraic equations. For weak absorption and linearly anisotropic scattering, the solution is given in closed form. (orig.).
As a part of a phenomenological model, a method for simulating the wall/jet interaction in a direct injection diesel engine is proposed. The method is based on the application of the momentum conservation equation in the different directions in which the wall jet is spread, and takes into account both the interaction with the combustion chamber geometry and with swirl. It takes as initial conditions the results of calculating the free jet, which is divided into packages. The predictions provide good agreement with those by other researchers. (author).
The numerical modelling of gravity changes resulting from the simultaneous effects of mass relocation and rock deformation is described. The method is supported by FEMMA (Finite Element Method for Multipurpose Applications) software, and has been used for modelling expected gravity changes in a large open pit coal mine in Poland. The results are in good agreement with conventional calculations of gravity changes for a simple geometry of relocated mass. 10 refs., 6 figs., 2 tabs.
The loop quantum cosmology 'improved dynamics' of the Bianchi type IX model are studied. The action of the Hamiltonian constraint operator is obtained via techniques developed for the Bianchi type I and type II models, no new input is required. It is shown that the big bang and big crunch singularities are resolved by quantum gravity effects. We also present effective equations which provide quantum geometry corrections to the classical equations of motion.
During four years of operation at the Central Receiver Test Facility (CRTF) ceramics have performed well in cyclic solar flux densities of less than 30 W/cm/sup 2/. Above 100 W/cm/sup 2/, serious limitations exist. Important application considerations include: the geometry, cyclic and long time exposures, flux density gradients, thermal shock, weathering, and soiling.
A correlation was developed for laminar film condensation on vertical fluted surfaces. The theoretical analysis of Panchal and Bell was used for defining important physical property groups. The experimental data of Combs et al. were used to validate the proposed correlation. The experimental database used in the present study included four flute geometries that could be approximated to cosine-type flutes and seven fluids. The resulting correlation can predict the average condensate heat transfer coefficient within {+-}20%.
Natural radioactive materials were used for detector calibration. We found that KCl is a very suitable material for this purpose. The efficiency curve shape was derived by using {gamma} ray lines of {sup 214}Bi normalised using a known quantity of KCl in the same geometry. The best fit was found by the least squares method. The summing correction coefficients for {sup 214}Bi are determined. (orig.).
Natural radioactive materials were used for detector calibration. We found that KCl is a very suitable material for this purpose. The efficiency curve shape was derived by using #gamma# ray lines of "2"1"4Bi normalised using a known quantity of KCl in the same geometry. The best fit was found by the least squares method. The summing correction coefficients for "2"1"4Bi are determined. (orig.).
We have investigated the detection performance of GaAs detectors made with different thickness and contact geometries. A comparison is made between these detection capabilities and the imaging requirements for the following medical applications: digital mammography, digital chest radiography and nuclear medicine. Experimental results and preliminary images are presented and discussed. (author)
This paper examines the seismic signatures of discrete, finite-length fractures, and outlines an approach for elastic, prestack reverse-time imaging of discrete fractures. The results of this study highlight the importance of incorporating fracture-generated P-S converted waves into the imaging method, and presents an alternate imaging condition that can be used in elastic reverse-time imaging when a direct wave is recorded (e.g., for crosswell and VSP acquisition geometries).
The effect of measurement geometry on the determination of the activity of solutions containing "1"2"5I for use in brachytherapy applications has been investigated for 5 mL plastic syringes and 2 mL conical glass dose vials as a function of filling mass. New dial settings for the syringes over a filling mass range of 1 to 3 g have been determined to be 497#+-#8 and 469#+-#8 (expanded, k=2, uncertainties) for the NIST Capintec CRC-12 and Capintec CRC-35R, respectively, with any effect due to the filling mass lying within the uncertainty in the activity calibration. A filling mass effect was observed in the dose vials, causing a 10.5% reduction in the chamber response from a 2 g filling mass to 1 g. Dial settings at 2 g were experimentally found to be 143#+-#2 and 135#+-#2 (expanded uncertainties) for the NIST Capintec CRC-12 and Capintec CRC-35R, respectively. The appropriate dial settings for the same vials with a 1 g filling mass were found to be 120#+-#2 and ...
Efficiency calibration curves for different densities and geometries are necessary for activity determination of various environmental samples. Commercially available standards or natural radioactive materials are used for calibration. Potassium compounds are especially suitable, since they can be mixed with unknown samples. It is possible to determine efficiency curve and unknown activity of sample knowing "4"0 K activity. (author).
We have used the unique spatial sensitivity of polarized neutron and soft x-ray beams in reflection geometry to measure the depth dependence of magnetization across the interface between a ferromagnet and antiferromagnet. The new uncompensated magnetization near the interface responds to applied field, while the uncompensated spins in the antiferromagnetic bulk are pinned, thus providing a means to establish exchange bias.
A multiwire cylindrical drift chamber is the main detector of the AMPIR 4#pi#-spectrometer for studying pion-nucleon reactions. The chamber has possibility to measure three coordinates by the electron drift time and by the charge division method. Chamber design and geometry, test bench, readout electronics and also results of calculations, simulation and tests are described.
The crabbing of an incident photon beam from a laser, and the electron beam with which it interacts at the conversion point, is shown to have the same efficiency as in head-on Compton scattering, but with the advantages of a crossing geometry. The resulting #gamma#-ray beam is also crabbed, which allows for a crossing collision point, while maintaining the luminosity at the same value it would have in a head-on collision.
The crabbing of an incident photon beam from a laser, and the electron beam with which it interacts at the conversion point, is shown to have the same efficiency as in head-on Compton scattering, but with the advantages of a crossing geometry. The resulting {gamma}-ray beam is also crabbed, which allows for a crossing collision point, while maintaining the luminosity at the same value it would have in a head-on collision. ((orig.)).
The crabbing of an incident photon beam from a laser, and the electron beam with which it interacts at the conversion point, is shown to have the same efficiency as in head-on Compton scattering, but with the advantages of a crossing geometry. The resulting #gamma#-ray beam is also crabbed, which allows for a crossing collision point, while maintaining the luminosity at the same value it would have in a head-on collision. ((orig.)).
A consistent combination of quantum geometry effects rules out a large class of models of loop quantum cosmology and their critical densities as they have been used in the recent literature. In particular, the critical density at which an isotropic universe filled with a free, massless scalar field would bounce must be well below the Planck density. In the presence of anisotropy, no model of the Schwarzschild black hole interior analyzed so far is consistent.
Here, we consider a recent paper concerned with magnetic braking by induced currents (Ireson and Twidle 2008 Eur. J. Phys. 29 745-51). Our objective is to elucidate why measurement of speed in which a magnet is dropped through a non-ferromagnetic conductive tube depends on its geometry in a non-monotonic way, which was not clearly explained by the authors. (letters and comments)
Critical power characteristics of tight lattice rod assembly was investigated using a simple-shaped experimental apparatus. An electrically heated rod with four spacers was placed in a circular tube, and boiling transition condition for a rod in an annular geometry was clarified varing annulus clearance. It was found that critical heat flux depends strongly on the clearance accoding as the gap becomes smaller. This results was compared with KfK correlation and the trends were well correlated. (author).
Henry constants for the adsorption of o- and p-phenylenediamines on the surface of graphitized thermal carbon black within the temperature range 433?479 K were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the nitrogen atom in aniline and isomeric phenylenediamines and the carbon atom of the basal face of graphite were determined. It was shown that an intramolecular H bond influenced the geometry and adsorption properties of o-phenylenediamine.
Henry constants for the adsorption of o- and p-phenylenediamines on the surface of graphitized thermal carbon black within the temperature range 433-479 K were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the nitrogen atom in aniline and isomeric phenylenediamines and the carbon atom of the basal face of graphite were determined. It was shown that an intramolecular H bond influenced the geometry and adsorption properties of o-phenylenediamine.
It is formulated Witten's proposal of a covariant open-string theory in terms of oscillator modes and shown that some basic axioms for the noncommutative geometry are obeyed as algebraic operations, which were defined previously from a geometrical point of view. Our strategy is based on the proper bosonization of the conformal ghost fields.
The dimensionally reduced effective action of the bosonic sector of the heterotic string in critical dimensions is employed to derive a Wheeler-DeWitt equation for the Bianchi type-IX cosmology. An exact solution is found that becomes strongly peaked around the isotropic limit as the volume of the three-geometry increases. In principle the global O(6,6) symmetry of the effective action can be employed to generate new solutions from the one presented here.
The dimensionally reduced effective action of the bosonic sector of the heterotic string in critical dimensions is employed to derive a Wheeler-DeWitt equation for the Bianchi type-IX cosmology. An exact solution is found that becomes strongly peaked around the isotropic limit as the volume of the three-geometry increases. In principle the global O(6,6) symmetry of the effective action can be employed to generate new solutions from the one presented here.
A numerical method for the calculation of unsteady, inviscid turbomachine flow in the transonic velocity range is described. The calculation of complete stages is possible. If the flow layer geometry is given, the flow field can be determined by independe...
Benchmark calculations for radiation transport coupled to a material temperature equation in a 1-D slab and 1-D spherical geometry binary random media are presented. The mixing statistics are taken to be homogeneous Markov statistics in the 1-D slab but only approximately Markov statistics in the 1-D sphere. The material chunk sizes are described by Poisson distribution functions. The material opacities are first taken to be constant and then allowed to vary as a strong function of material temperature. Benchmark values and variances for time evolution of the ensemble average of material temperature energy density and radiation transmission are computed via a Monte Carlo type method. These benchmarks are used as a basis for comparison with three other approximate methods of solution. One of these approximate methods is simple atomic mix. The second approximate model is an adaptation of what is commonly called the Levermore-Pomraning model and which is referred to ...
A spherical-geometry, self-extraction negative ion source has been designed and fabricated. The source utilizes direct surface ionization to form negative ion beams resulting from interactions between high electron affinity gaseous elemental or molecular materials and a negatively biased, spherical-sector LaB{sub 6} surface ionizer maintained at {similar to}1300 K. The design features of this source and principles upon which the source is based are discussed in this report.
A new nonlinear S{sub n} transport differencing scheme for slab geometry is presented that is fourth order accurate for small meshes and is strictly positive. The new scheme has been coded into the existing ONELD code and tested. Numerical results to demonstrate the accuracy and positivity of this new scheme are presented.
During the last several years, audible noise produced by high voltage transmission lines in corona has emerged as an important design consideration. In this same time frame a number of different methods for calculating audible noise levels have been proposed. The methods currently available, for both ac and dc lines, are described in this paper and are compared through application to practical line geometries for which data from long-term measurements are available.
{sup 60}Co is produced as an activation product and is present in the low-level aqueous radioactive waste released from the La Hague plant. At present, the concentration in the sea (non filtered at 0.45 {mu}m) at the Goury site are close to or even below, the detection limit: 0.2 mBq.l{sup -1}. The {sup 60}Co speciation depends on the type of effluent considered: in the effluent A ('active'), the cobalt is in the form of a stable trivalent complex; in the effluent V (to be checked), the cobalt is in majority (50% of the activity release) in the form of particles (>0.45 {mu}m), and then in the form of two soluble species: ionic divalent (Co{sup 2+}) and some stable complexes. The evolution of the reprocessing techniques used does not affect the speciation. So, since the nuclear reprocessing plant started at the La Hague plant in 1966, the chemical species discharged in the sea shows time variation related to the evolution of the type of effluent discharged. ...
The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas will be described in this paper. The pre- and postoperative imaging of the temporal bone was performed with HRCT and MRI. HRCT and MRI were performed in the axial and coronal plane. MRI was done with T2 weighted and T1 weighted sequences both before and after the intravenous application of contrast material. All imaging findings were confirmed clinically or surgically. The preoperative cholesteatoma-caused complications depicted by HRCT included bony erosions of the ossicles, scutum, facial canal in the middle ear, tympanic walls including the tegmen tympani, and of the labyrinth. The preoperative cholesteatoma-caused complications depicted by MRI included signs indicative for labyrinthitis, and brain abscess. Postoperative HRCT depicted bony erosions caused by recurrent cholesteatoma, bony defects ...
The staging of patients with multiple myeloma demands sensitive imaging methods for the assessment of the skeletal system. MRI allows for direct visualization of the bone marrow which exhibits five different infiltration patterns in multiple myeloma: 1. normal appearance of the bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltration, 5. ''salt and pepper'' pattern with inhomogeneous bone marrow signals due to multiple fat islands. The combination of T1w-SE and STIR sequences is best suited for detecting all infiltration patterns and for the differential diagnoses e. g. hemangiomas. With parallel imaging in MRI, acquisition times can be markedly reduced and whole-body screening of the bone marrow can be achieved within 30 min. MRI is superior to radiography for the detection of focal as well as diffuse infiltration. Multidetector computed tomography and especially 16- and 64-detector row ...
This final report for the Swiss Federal Office of Energy looks at the possibilities for improved waste water utilization in the Lavey-les-Bains thermal spa, Switzerland. According to the regulations in force, the temperature of the waste water rejected into the Rhone river shall not exceed 30 {sup o}C, what is currently not the case. Also the operational cost shall be reduced and the waste water quality improved. The installations are presented. From the two geothermal wells, mineral water comes out at an average flow rate of 940 l/min and a temperature of 63 {sup o}C. Actual waste water data are reported. The measured thermal water consumption data, including seasonal variations, are analysed by computerized simulation and measures to reduce the consumed volume by the optimization of internal procedures are evaluated. Measures to reduce the quantity of the rejected free chlorine are discussed. Several possible adaptations of the existing space heating, domestic water heating and ...
The Ministere des Ressources naturelles du Quebec (Quebec Natural Resources Department) implemented a remedial program to treat the waste rock pile at Wood Cadillac, located near Cadillac, in Abitibi, Quebec. The solutions proposed by INRS-Georessources and ENVIROCONSEIL are aimed at eliminating erosion and stabilizing the geochemical processes. Part of the proposed solution also included the use of a reducing trickling filter for the treatment of acid leachates, which also contain arsenic when exiting the waste rock pile. The trickling filter is composed of forest tailings in which the bacteria reduce the sulphates and stimulate the precipitation of arsenic into arsenic sulphates. This is a new treatment that was developed following laboratory experiments which demonstrated the feasibility of the process and quantified the parameters. A demonstration unit was constructed by ENVIROCONSEIL and installed at the Wood Cadillac waste rock pile under the supervision of ...
The project is intended to yield information on the transfer factors describing the transfer of ingested radionuclides to breast milk for the following elements: antimony, cerium, chromium, cobalt, gallium, lanthanum, molybdenum, niobium, radium, ruthenium, silver, thorium, titanium, and uranium. Those yet unknown or poorly known transfer factors are required in order to be able to develop a reliable model for description and assessment of the transfer of the radionuclides and the possibly resulting hazardous doses to infants, and for subsequent formulation of recommendations for radiological protection of the population. (orig./CB) [German] Ziel des Projektes ist die Ermittlung von Transferfaktoren fuer den Uebergang von Radionukliden aus der Nahrung der Muetter in die Muttermilch fuer die Elemente Antimon, Cer, Chrom, Cobalt, Gallium, Lanthan, Molybdaen, Niob, Radium, Ruthenium, Silber, Thorium, Titan und Uran. Um die Exposition und damit die moegliche Gefaehrung ...
R?sum? La rate baladeuse est une anomalie rare chez l?enfant. Elle est souvent d?crite chez l?adulte, particuli?rement la femme enceinte. Elle est due ? un d?faut de fixit? anatomique de la rate avec les organes de voisinage. Ses manifestations cliniques sont variables, mais la complication la plus redoutable est la survenue d?une torsion du p?dicule spl?nique. Nous rapportons le cas d?une fille de 11 ans qui s?est pr?sent?e avec des douleurs abdominales aigu?s et des vomissements. Les examens radiologiques ont montr? une absence de la vascularisation spl?nique. ? l?exploration chirurgicale, on a d?couvert une torsion du p?dicule spl?nique avec une isch?mie tissulaire avanc?e. La rate ?tait d?pourvue d?attaches ligamentaires. La d?torsion n?a pas permis de sauvegarder la rate, et une spl?n...
A single exposure energy subtraction technique with a metal filter and an imaging plate for the Fuji Computed Radiography (FCR) system was developed for dual-energy subtraction radiography (DES) of the chest. By the use of this technique, 206 patients with suspected lung cancer were scanned in the clinical settings. The subtracted images in 200 patients, excluding six with poor image quality, were examined. Soft-tissue images (bone cancelled images) were useful in visualizing abnormality of the airway and nodules lying under the ribs; and bone images (soft-tissue cancelled images) in detecting rib metastases and the presence or absence of calcification in nodules. Additional information was acquired in 21 % (42/200). A single exposure is capable of neglecting motion artifacts. In addition, this technique may be of value in DES, which is considered to be one of the routine examinations, in view of low exposure doses. The need of conventional ...
A single exposure energy subtraction technique with a metal filter and an imaging plate for the Fuji Computed Radiography (FCR) system was developed for dual-energy subtraction radiography (DES) of the chest. By the use of this technique, 206 patients with suspected lung cancer were scanned in the clinical settings. The subtracted images in 200 patients, excluding six with poor image quality, were examined. Soft-tissue images (bone cancelled images) were useful in visualizing abnormality of the airway and nodules lying under the ribs; and bone images (soft-tissue cancelled images) in detecting rib metastases and the presence or absence of calcification in nodules. Additional information was acquired in 21 % (42/200). A single exposure is capable of neglecting motion artifacts. In addition, this technique may be of value in DES, which is considered to be one of the routine examinations, in view of low exposure doses. The need of conventional ...
For the laying of natural gas transport pipelines severe soil protection guidelines are in force in Switzerland. These guidelines influence, above all, the course of the construction in a substantial way. The Federal Office of Energy promulgated these guidelines in May 1993. They have provisional character and shall be reviewed based on the experiences with the in 1994 executed pipeline constructions. The protection of the soil from mechanical-physical loads, specially from soil erosion and compaction, is also a part of the modification of the federal legislation concerning environmental protection which is being dealt with at present by the federal parliament. (orig.) [Deutsch] Fuer die Verlegung von Erdgas-Transportleitungen gelten in der Schweiz strenge Bodenschutzrichtlinien, die vor allem den Bauablauf nachhaltig beeinflussen. Die Richtlinien wurden im Mai 1993 durch das Bundesamt fuer Energiewirtschaft erlassen. Sie haben provisorischen Charkater und sollen aufgrund der ...
On February 20th 1998 Auckland, the biggest city of New Zealand, was nearly paralyzed by an extended power failure. On this day the last of four cables supplying the central business district failed and caused a five weeks lasting blackout. This failure has caused costs of 128.3 Mio NZ Dollar for the affected utility Mercury Energy Ltd. The official ministerial inquiry was published on July 21st 1998 and reproaches the utility in an unusual clear manner. (orig.) [Deutsch] Am 20. Februar 1998 wurde Auckland, die groesste Stadt Neuseelands, von einer folgenschweren Unterbrechung der Stromversorgung nahezu lahmgelegt. An diesem Tag fiel das letzte von vier 110-kV-Kabeln zur Versorgung des Innenstadtbereiches aus und verursachte damit einen 5 Wochen dauernden Stromausfall. Diese Versorgungsunterbrechung hat bisher Kosten in Hoehe von 128,3 Mio NZ Dollar (rd. 115,5 Mio DM) fuer den oertlichen Stromversorger Mercury Energy Limited verursacht. Der am 21. Juli 1998 ...
Proactive qualification is today an integral part of the development process for steam turbines used in steam and combined cycle power plants. By providing experimentally based `random` variables, such as the steam path efficiency and blading reliability, it makes a valuable contribution to the economic `random` variables of the power plant, e.g. the rate of return, as viewed by the customer. One of the areas in which proactive product and process qualification plays an important role is the development of LP steam paths. (orig.) [Deutsch] Die proaktive Qualifikation ist heute fester Bestandteil des Entwicklungsprozesses bei Dampfturbinen, die fuer den Einsatz in Dampf- und Kombikraftwerken bestimmt sind. Sie leistet mit Hilfe experimentell ermittelter `Zufalls`-Variablen, wie z.B. Wirkungsgrad der Fluten und Zuverlaessigkeit der Beschaufelungen, einen wertvollen Beitrag zu den fuer die Kunden wichtigen wirtschaftlichen `Zufalls`-Variablen des ...
Controls of welds by radiographies are an efficient non destructive technique but it can be dangerous if not managed following a strict set of rules. EDF acts to avoid risks via several ways (adapted tools, best practices) and seeks for an integration of the radiographies with respect to the other maintenance operations, in order to raise the ratio of availability of the electricity production unit. This study explores an original analysis of industrial radiography: the influence of the representations of the workplace and its utilizations. This document supports the utilization of some space constraints as explanations of difficulties in the industrial radiography activity. The document proposes innovative points of view coming for on-site observations and from a theoretical background 'cognitive sciences' completed by technical propositions. (author)
LP steam turbine retrofits are generally undertaken as a result of mechanical problems, for example due to stress corrosion cracking, torsional vibration or erosion. They present plant operators with an opportunity to introduce advanced aerodynamic technology, and at the same time improve efficiency and availability. Standard components, the majority proven in long-term service, can be used to obtain a permanent solution to the problems. In several European countries, retrofits have been carried out on intact LP steam turbines owned by utilities whose primary motivation is efficiency improvement. (orig.) [Deutsch] Niederdruck-Dampfturbinen werden in der Regel nur dann nachgeruestet, wenn waehrend des Betriebes Probleme durch Spannungsrisskorrosion, Torsionsschwingungen oder Erosion auftreten. In solchen Faellen bietet sich die Gelegenheit, eine moderne aerodynamische Loesung zu waehlen, die gleichzeitig Wirkungsgrad und Verfuegbarkeit verbessert. Es wird gezeigt, ...
For the inventory of water tritium concentration in the Manche department, it is the complementarity that animated the work opened during year 2001. To answer to a commune sensitivity such water quality, particularly drinking water at tap, the A.C.R.O. laboratory brought its know how to make and its technical means in the area of tritium analysis and the general council brought its know how to make and its logistics means in matter of sanitary control. This collaboration has allowed to supply an indication on the tritium content of the distribution waters of thirty of the most important cities of the department. Then, it allowed to inform on the radiological situation (in relation with the tritium presence) of coast waters and principal rivers waters. More than 160 controls have been realised between the months of march 2001 and february 2002. Only the tritium under the shape of tritiated water has been measured. The measures have been made by liquid scintillation according to the ...
In this paper, we present the work carried out within the framework of the FEVER project (Fuel cell Electric Vehicle for Efficiency and Range), an European project coordinated by Renault, joining Ecole des Mines de Paris, Ansaldo, De Nora, Air Liquide and Volvo. For the FEVER project, where an electrical air compressor is used for oxidant supply, there is no need for hydrogen spill over, meaning that the hydrogen stoichiometry has to be as close to one as possible. To determine the optimum hydrogen utilization efficiency for a 10 kW Proton Exchange Membrane Fuel Cell (PEMFC) fed with pure hydrogen, a 4 kW prototype fuel cell was tested with and without a hydrogen recirculator at the test facility of Ecole des Mines de Paris. Nitrogen cross over from the cathodic compartment to the anodic compartment limits the hydrogen utilization of the fuel cell without recirculator to 97.4 % whereas 100% is feasible when a recirculator is used. 5 refs.
The second volume contains a comprehensive presentation of inflammatory bone diseases, including seldom primary chronic osteomyelitis and morbus Paget. Substantial chapters on bone tumors and tumor-like lesions of bone joints are covering the state-of-the-art of diagnostic techniques of these seldom but important diseases. Besides the importance of projection radiography the contribution of MRI within differential diagnosis und staging of these diseases is emphasized. [German] Der zweite Band des Muskuloskelettalen Systems befasst sich mit der umfassenden Darstellung zur Diagnostik entzuendlicher Knochenerkrankungen und beinhaltet neben den klassischen infektioesen auch die seltenen, primaer chronischen Osteomyelitiden und den Morbus Paget. Umfangreiche Kapitel ueber die Knochentumoren und tumoraehnlichen Laesionen der Gelenke stellen in modernster Weise den aktuellen Stand des Wissens und der Diagnostik dieser seltenen, aber aus ...
In the course of the research project 'Investigations of trace element concentrations in coal seams with different mineral groups', 31 seam coals of the Ruhr Carboniferous were analysed in order to determine the bending of 14 coal-relevant trace elements to the mineral groups and/or minerals of the coals. Products with different ash content were produced by fluctuation of the seam coals in a laboratory cell. The raw coals and fluctuation component products were analyzed chemically and mineralogically in order to get a quantitative raw material characterisation of the sampled material. Particular interest is taken in the chemical and non-ecological composition of the mineral as ash carrier in the coal and the fluctuation component products, as well as in trace element control. (orig./EF).
The examples quoted show that damage is mostly due to faults of design and construction or faulty operation. The ever shorter development cycles, the further development of existing constructions and cost pressure owing to price slumps are very important in this context. Careful endoscopic inspections and monitoring and early identification of beginning damage helps to prevent major damage and follow-up damage. The causes of changing operational performance must be established as early as possible to prevent larger damages from being caused by continued operations.(orig.) [German] Die vorgestellten Schadenbeispiele zeigen, dass die Schaeden vorwiegend durch Auslegungsfehler und Konstruktionsfehler aber auch durch Bedienungsfehler verursacht wurden. Die immer kuerzeren Entwicklungszeiten fuer Neukonstruktionen und die Weiterentwicklung vorhandener Konstruktionen sowie der Kostendruck infolge des Preisverfalles sind hierbei von grosser Bedeutung. Weitherhin ist die ...
Developments in the past 10 -15 years in the fiels of `steel`, `boilers`, `steam turbines` and `environmental protection` show that the advanced coal dust furnace technology is another option of clean coal technology. The contribution discusses some of the current problems facing the main partners of the coal sector, e.g. coal producers, public utilities and suppliers of steel, boilers and turbines. (orig./GL) [Deutsch] Die Entwicklung der vergangenen 10-15 Jahre in den Bereichen `Stahl`, `Kessel`, `Dampfturbinen` und `umweltschutztechnische Anlagen` verdeutlicht, dass die fortgeschrittene Kohlestaubfeuerungstechnologie ebenfalls eine Option der `Clean Coal Technologies` ist. Im Rahmen dieses kurzen Aufsatzes wird nun versucht, einige zeitgemaesse Problemkreise der Hauptakteure des Strommarktes, wie z.B. des Kohlefoerderers, der Stromproduzenten und der Stahl-, Kessel- sowie Turbinenhersteller anzudeuten. (orig./GL)
The analyses were carried out using real climate data for the years 1987 and 1989. The course of the indoor climate for year-round free ventilation with a constant flow volume is discussed. Numerous diagrams inform on ambient temperature, water vapour content, the condition of space air, and temperature drops below dew point. For the event of heating of the central part of the church, space air condition, the annual air humidification requirement, and the temperature field in this part of the building are described. (MSK) [Deutsch] Die Untersuchungen wurden mit aktuellen Klimadaten fuer die Jahre 1987 und 1989 durchgefuehrt. Der Verlauf des Raumklimas bei ganzjaehrig freier Klimatisierung mit konstantem Foerderstrom wird erlaeutert. Dabei wird die Raumlufttemperatur, der Wasserdampfgehalt, der Raumluftzustand sowie die Taupunktunterschreitung in zahlreichen Diagrammen aufgezeigt. Weiter werden fuer den Fall der Beheizung des Hauptraums der ...
The wastes management policy takes into account more and more often the environmental impacts mastership. This evolution is particularly appreciable when the wastes directly interact with the environment: storage, utilization for roads construction and so on. In this context the ADEME organized the 8 june 2000 a colloquium to present the new evaluation methods and tools, to describe the regulations and to identify the research programs needed for this environmental policy. Eleven papers are presented. (A.L.B.)
Although the oil price is still far from its historical maximum, the oil market is today in crisis. To explain this situation the author discusses the nature of the supply constraints. The reserves are today better known and so more plentiful than at a previous period of the oil history and the russian production since 2004 is stagnating. The main factor seems to be the OPEC policy and in particular the will of limiting the oil production to defend upper prices. (A.L.B.)
The European Court of Justice has defined a clear means by which waste utilisation methods can be distinguished from waste disposal methods in a logical, well-understandable manner. With its stringent definition of ''utilisation'' this judgement points the way to quality-oriented waste management practices. We do not share the often voiced fear that this decision will lead to an increased incineration of compound wastes in industrial plants such as cement works. From the fact that, according to the decision by the European Court of Justice, wastes destined for utilisation fulfil a certain purpose and therefore, if not available in sufficient quantity must be replaced by primary raw materials, it follows that these wastes are required to fulfil specific quality criteria. This is rarely the case, if at all, with compound wastes. From the viewpoint of Luxembourg the decision by the European Court of Justice can be regarded as a positive impulse towards ...
The survey of radiation protection programmes for transport has been jointly performed by three scientific organisations I.P.S.N. (France), G.R.S. ( Germany), and N.R.P.B. (United kingdom) on behalf of the European Commission and the pertaining documentation summarises the findings and conclusions of the work that was undertaken with the principal objectives to provide guidance on the establishment, implementation and application of radiation protection programmes for the transport of radioactive materials by operators and the assessment and evaluation of such programmes by the competent authority and to review currently existing radiation protection programmes for the transport of radioactive materials. (N.C.)
The French office for technical studies and control of big dams (BETCGB), has recently reedited the `guidebook for the control of dams in exploitation`. The aim of this document is to provide to the regional directions of industry, research and environment (DRIRE) a methodological help for their control actions of hydroelectric dams granted for exploitation. It comprises 6 chapters dealing with: the different type of dams, the inspection, the surveillance, the floods evacuation, the flood instructions, and the particular emergency plans. (J.S.)
This report is published in the framework of the 1991 French law for the nuclear waste management. The state of the art reported here concerns the long term evolution of spent fuel in the various environmental conditions corresponding to dry storage and geological disposal: closed system, air and water saturated medium. This review is based on the results of the french PRECCI project (Research Program on Long term Evolution of Spent Nuclear Fuel) and on literature data. (authors)
The study required by the West German Ministry of Research and Technology (RS 605) for the Committee on 'Future Nuclear Energy Policy' of the 9th German Parliament is concerned with the following main points: 1) Assessment of technical risks from the social aspect; 2) Discussion of terms and quantification of risks; 3) 'Engineering judgment' and 'questionable' methods in the Fast Breeder analysis of the Society for Reactor Safety (GRS); 4) Assessment criteria of potential damage.
The accuracy of the carbon 14 dating method is dependent on the fluctuations of carbon 14 in the atmosphere over long periods of time. Fossil corals that are dated by both carbon 14 and uranium-thorium methods allows the setting of calibration curves for the carbon 14 method for the last 50.000 years. The uranium-thorium method is based on the measurement of the ratio of 2 isotopes: thorium 230 and uranium 234 that are both present in the decay chain of uranium 238. (A.C.)
The work opened by the A.C.R.O. is in line with in an initiative of evaluation of the radiological quality of marine and continental waters of the Normandy coast. In this perspective, measures of radioactivity were made, not near an emissary (already very watched environment) but in more large scale because in marine environment, more than 640 km of coast are concerned. It was a question of supplying a representative assessment of the radioecological situation, for one year,of the marine environment (along the Normandy coast) and main streams which supplies it. (N.C.)
Court decisions available so far do not primarily consider the problems linked to the commissioning of an expert and his mandate, as well as the legal status of the commissioning of an expert as an administrative act which might be legally contestable. Thus there are at present no court decisions that would create legal certainty in matters of the act of commissioning a nuclear expert opinion. The current legal situation is such that an independent order for commissioning of an expert opinion in compliance with section 19 III AtG (Atomic Energy Act), which in general is given in response to the refusal of the facility operator to do so, can be independently contested on the basis of section 44 a, sentence 2 VwGO (Rules of Administrative Courts). The current practice of conflict-oriented, or nuclear power phase-out-oriented, implementation of the nuclear law poses a threat to our constitutional state and to our democracy. The supply of energy as a common good is of essential importance ...
A major component of the 1990 recommendations of ICRP (ICRP, 1991a) was the revision of the dose limits. But other changes were introduced which necessitated a review of earlier guidance. In particular, ICRP set up a Task Group in 1993 to prepare a report on the principles for the protection of workers. The report was adopted in 1997 and has now been published as ICRP Publication 75 (ICRP, 1997). It is for others to judge the real significance of the guidance provided; what follows are some of the main points. (author)
The defects localization in power cables follows several steps: identification, pre-localization and precise localization. Pre-localization methods, other than echo-metry, are presented first: bridge methods, particular case of low voltage networks, future perspectives. Then, the precise localization methods are described: magneto-acoustic method, audible frequencies method. The particular case of underwater and high-voltage cables is considered too (oil and gas leaks detection). (J.S.)
This paper presents fundamental researches based on the electronic structure calculations and X absorption spectroscopy, allowing the knowledge on nuclear fuels at an atomic scale. They bring a better understanding of these material behavior to accurate the macroscopic simulation. The calculation methods, the experimental techniques of validation and the ab initio calculations results are detailed. (A.L.B.)
Lung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification are measurable with MRI. Pulmonary nodules can be detected at the clinically relevant size of 4-5 mm in diameter. The extent of mediastinal, hilar and supraclavicular lymph node affection can be assessed at the same time. The predominant metastatic spread to the adrenal glands and spine can be detected in coronal orientation during dedicated MRI of the lungs. Search focused whole body MRI completes the staging. Various additional MR imaging techniques provide further functional and clinically relevant information during a single examination. In the oncological context the most important techniques are imaging of perfusion and tumor motion. Functional MRI of the lungs complements the pure staging and improves surgical approaches and radiotherapy planning. (orig.) [German] Das Staging ...
There is much interest worldwide in low-emission, low-noise electric cars. Modern vehicles with advanced technology are an interesting alternative to conventional cars. (orig.) [Deutsch] Das Interesse an den emissionsfreien und leisen Elektroautos ist weltweit ungebrochen. Die heute verfuegbaren Fahrzeuge zeigen die betraechtlichen, in den letzten Jahren erzielten Fortschritte, die sie fuer immer mehr Anwender zu einer beliebten Alternative zur Benutzung des konventionellen Autos machen. (orig.)
The nuclear structure of A {proportional_to} 100 nuclei has been studied in the frame of this thesis with a recently developed {beta} - {gamma} - {gamma} triple coincidence fast timing technique and different models such as shell model, hydrodynamic model, Nilsson and particle-rotor models. This technique which allows the measurement of the level lifetimes in the ps range has been applied at JOSEF at the research reactor DIDO of KFA Juelich in studes of the short-lived neutron-rich nuclei in the A {approx_equal} 100 region. Lifetimes of level in {sup 96},{sup 98},{sup 100} ZR, {sup 99},{sup 101}-{sup 104} Nb, {sup 100}-{sup 105} Mo have been measured, which are in many cases completely new, and otherwise more precise than previously published data. From the lifetimes of the members of rotational bands, the size of the nuclear deformations has been deduced. (orig./HSI). [Deutsch] Im Rahmen dieser Doktorarbeit wurde die Kernstruktur der A {proportional_to} 100 Kerne untersucht. Dazu ...
The transversus perinei profundus muscle is a well known structure in found anatomical textbook. Fibres of this muscle are believed to form the so-called external urethral sphincter (musculus sphincter urethrae). Recently histomorphologic investigations have shown that there is no muscular connection between the musculus sphincter urethrae (external sphincter) and the muscle system of the pelvic floor. Furthermore, the external sphincter was found to be divided into parts: The transversely striated part (musculus sphincter urethrae transversostriatus) and the smooth part (musculus sphincter urethrae glaber). Similar to histomorphologic investigations, contrast-enhanced MR imaging has shown the musculus sphincter urethrae to be surrounded by fatty and connective tissue only. Neither in MRI nor in anatomical slices can any connection between the urethral sphincter and the muscle system of the pelvic floor be found. Thus, on the basis of the results presented in this work it is concluded ...
The report discusses: Combustion characteristics of various commercial cokes for cupola furnace operation; quality level of modern cokes; foundry coke, blast furnace coke, MB coke; characteristic data, e.g. grain size distribution, drum resistance, concentrations of water, carbon, sulphur, ash, and volatiles, reactivity; changes in coke quality during transport. (HS)
An investigation of the solidification behavior was carried out on the directionally solidified single crystal superalloy CMSX 6. The relationship between structure morphology and the process parameters has been experimentally determined and illustrated in a solidification diagram. The metallographic analyses of transverse sections within the solidification interval yield the sequence of phase formation and the evolution of solid fraction. The solidification process and the corresponding structure have been discussed in detail. (orig.)
A 2D matrix allows a fairly rapid verification of irradiation parameters transferred on computer processing equipment without expanding the dosimetry means to implement. Associated to 'Multicheck and Verisoft' software it will handle some of the regulatory recommendations of the A.F.S.S.A.P.S. for quality control of accelerators and ensure the traceability of testing carried out. (N.C.)
Two hypotheses are in the centre of this investigation, on the one hand the question, whether microwaves as exogenous fields alone are able to stimulate human muscle cells above-threshold, and on the other hand, whether microwaves as conditioning to cathodical electrical pulses can modify the excitation threshold and form. No excitation through the application of microwaves alone can be introduced at any subject. The conditioning of above-threshold cathodical electrical pulses with UMTS-microwaves leads not to a transgression of the threshold or the electrical muscle response (EMG) depending on the amplitude, the duration or the dose rate. (orig.)
In the framework of the carbon storage two forestry methods are analyzed by the author: the standing capitalization (slowing of the crops) and the spices substitution (slow growing species by fast growing species). The construction of a model taking into account the all stage of the carbon implication (biomass, soil, forest products) offers simulation and quantitative results on these methods. (A.L.B.)
Progress reports on the European Research Centre for Air Pollution Control Measures project are presented. Topics covered were: assessment and analysis of the impacts of airborne pollutants on forest trees, and distinction from other potential causes of recent forest dieback; research into atmospheric dispersion, conversion and deposition of airborne pollutants; development and optimization of industrial technical processes to reduce or avoid emissions; and providing instruments and making recommendations to the industrial and political sectors.
High-voltage transmission lines can pose an environmental problem, especially in countries where the electricity production is at a distance from the demand location. Planning, construction, and operation of high voltage transmission lines should be conducted within a comprehensive environmental policy, which may include assessment of visual impact, landscape and wildlife protection, and reduction of health risks. This paper reviews the environmental policies and action in planning, construction, and operation as developed by the utilities members of the Union Internationale des Producteurs et Distributeurs d`Energie Electrique (UNIPEDE). The paper also presents a brief outline of the health issues associated with the effects of electromagnetic fields to humans.
High-voltage transmission lines can pose an environmental problem, especially in countries where the electricity production is at a distance from the demand location. Planning, construction, and operation of high voltage transmission lines should be conducted within a comprehensive environmental policy, which may include assessment of visual impact, landscape and wildlife protection, and reduction of health risks. This paper reviews the environmental policies and action in planning, construction, and operation as developed by the utilities members of the Union Internationale des Producteurs et Distributeurs d'Energie Electrique (UNIPEDE). The paper also presents a brief outline of the health issues associated with the effects of electromagnetic fields to humans.
In order to improve the capacity and service life of cathodes, the effect of carboxy-methyl cellulose, soot, silica gel and fibres was examined. Structural tests and electrical and electro-chemical measurements are used for this. The additives can affect crystallization in the manufacturing stage of the electrodes and can increase the storage capacity for water and the electronic conductivity. They act to stabilize the mass in cyclic operation. Soot additive has little effect on the properties of the electrode, but the other substances increase the service life or the use of the mass. (LU).
Vol. 4 of the DKV Conference Proceedings 2000 contains 19 papers on air quality, thermal comfort, space HVAC engineering and alternative cooling concepts. [German] Der Band 4 des DKV-Tagungsberichts 2000 enthaelt 19 Beitraege. Sie befassen sich mit speziellen Themen der Heiztechnik; Luftqualitaet und Behaglichkeit; Raumlufttechnik und Alternativen Kuehlkonzepten.
This book of proceedings reports on 7 papers on combustion chemistry and formation of pollutants presented during the workshop organized by the `Combustion and Flames` section of the French society of thermal engineers. The chemistry of combustion is analyzed in various situations such as: turbojet engines, spark ignition engines, industrial burners, gas turbines etc... Numerical simulation is used to understand the physico-chemical processes involved in combustion, to describe the kinetics of oxidation, combustion and flame propagation, and to predict the formation of pollutants. (J.S.)
We studied 129 AIDS patients with suspected or proved intracranial manifestations of the disease. The purpose of this study was to compare the diagnostic sensitivity of unenhanced and contrast enhanced CT and unenhanced T{sub 2}-weighted MR. Thus, in 20% of our patients MR but not CT was diagnostic. In another 20% MR provided additional diagnostic information. In conclusion, MR is recommended as the imaging modality of choice in AIDS patients with non-conclusive cranial CT. (orig./GDG).
This report completes the documentation for the research project 'High Pressure Compressor - Preliminary Design as Basis for the Development of an Efficient and Environmentally Friendly Core Engine' which was funded by the Ministry of Economics of State Brandenburg. The objective of the project is to deliver a preliminary compressor aerodynamic design as well as design studies for an efficient, weight and cost improved compressor. The increase of stage pressure ratio and improved efficiency, whilst stage and blade count is reduced, has been achieved by advanced 3D methods. Compressor stability also at off-design conditions will be retained. The mechanical design focusses on a cost and weight optimised rotor not only for a conventional bladed discs but also for Blish stages. Various options for split casings have been developed and assessed. Alternative vortex reducers based on different design options have been carried out. The results from this project will be ...
In cooling systems, an improved control of scale deposit and corrosion processes is a major challenge and an realistic evaluation tool for water treatments is of the utmost economic importance. In this study, a channel flow cell was used to allow in-situ electrochemical measurements in well defined electrolyte tube flowing conditions. An expression of the mass transfer towards the electrode was established where the diffusion-limited current is a function of Re{sup 1/3} in the laminar regime and was verified experimentally using the redox couples Fe[CN]{sub 6}{sup 4-}/ Fe[CN]{sub 6}{sup 3-} and O{sub 2}/OH{sup -}. This hydrodynamically controlled experimental device was developed to investigate scale deposit processes and to evaluate scale inhibitor efficiency using a electrochemical quartz crystal microbalance. Experiments were performed on three different waters, at various flow rates and temperatures. The efficiency of a well known phosphonate (HEDP) was tested at different ...
The mass generation in the Standard Model of Particles Physics relies on a spontaneous symmetry breaking mechanism. Its implementation is recalled, along with its constraints, both theoretical (Naturalness, Stability, Triviality, Unitarity) and experimental (limits of direct and indirect searches, prospects). Calculation techniques for observables evaluation in Perturbative Field Theory are described, particularly Helicity Amplitude method, which is given in details: fermions and vector bosons, massless and massive. Monte-Carlo integration, and structure functions approximations (which allows non-perturbative calculations) are also detailed. With these tools, a process giving to Physics beyond the Standard Model is studied: it leads to an experimental prediction for the LEP collision ring, taking the classical background into account. Technical aspects of a future photon linear collider are reviewed. The production of heavy vector bosons, either the classical Z for the hypothetical ...
The present thesis presents two different aspects of my work in the L3 experiment, which are on one side the search for supersymmetric particles, the scalar leptons, in two different topologies 'electron + X + E' and '2 leptons + 2 photons + E', each of them being related to two theoretical SUSY models, m-SUGRA and GMSB. On the other side my work has been completed by the study of the BGO crystal electromagnetic calorimeter of L3, and the calibration of the electromagnetic calorimeter EGAP. After the essential motivations being reviewed, the production and disintegration modes are detailed concerning the scalar lepton sector at LEP. Then one presents the analysis techniques which I used to perform my selection, and also the results obtained from the data collected by L3 for center of mass energies between {radical} S =183 GeV and 202 GeV. The selection criteria that allow to isolate the events I looked for, including efficiencies but also the ...
Although the standard model of particle physics agrees perfectly with experimental data, it is unlikely the final theory describing particles and their interactions. New phenomena has been searched in the jets and missing transverse energy topology. Such phenomena may be due to the pair production of leptoquarks decaying into a quark and a neutrino or the pair production of stops decaying into a charm and a neutralino which is assumed to be the lightest supersymmetric particle. These searches have been performed with the Ddiamter detector at hadronic collider TeVatron with a center of mass energy of 1.96 TeV. This kind of searches needs a good understanding of the jet energy calibration. The determination of the relative jet energy scale has allowed us to reduce the systematic uncertainties on the jet energy measurement when comparing the data and the simulation. Moreover a new method has been developed in order to correct simulated jets for the differences observed in the jet energy ...
The aim of this study concerns the use of numerical methods for the resolution of the Reynolds Averaged Navier Stokes equations adapted to the simulation of the cooling of the trailing edge of a stator in a high pressure turbine. These methods, based on the elsA solver developed at ONERA, use a four steps Runge Kutta time discretization scheme and a Jameson centered space discretization scheme. The scheme is applied through a finite volume approach on control volume centered on the cells of a multi-block structured mesh. Turbulence is simulated either through the algebraic Michel model, or through the one-transport-equation Spalart-Allmaras model, or through the two-transport-equations k 1, k {omega} and k {epsilon} models, and through ASM model. A simulation of the flow in a bidimensional stator, without cooling, is carried out. The cooling, which is realized with trailing edge slots, is then simulated on a bidimensional stator. Because the slot is represented by meshes overlapping ...
Samples of Parmelia sulcata and Xanthoria parietina from different biotopes have been analysed for elements of the series of uranium 238 and thorium 232. These species have been used as bio-monitors in different cases : urban areas, coal fired power plant, tip for uranium-mining residues. The concentration of most of these elements in lichens is decreasing as follows: radium waste-disposal site > area with uranium-rich soil > urban area > rural area. Road traffic was not found to increase notably the presence of radioactive lead in the environment. The two foliose lichens seem to have a comparable concentration ability, but Parmelia sulcata appeared to be more reliable. Some of the elements under investigation could be particularly problematic from a sanitary point of view: the intake limits in case of inhalation are very low and the atmospheric deposition is not negligible; this is particularly so for lead 210 and thorium 228. These elements should not only be monitored on a ...
V{sub 2}O{sub 5} based compounds are interesting low potential materials for rechargeable cathodes of lithium electrochemical generators. However, the ionic conductivity and the reversibility of electrochemical cycling of V{sub 2}O{sub 5} are limited by the possibilities of lithium insertion. This work shows that the doping of vanadium pentoxide by a M{sup 3+} trivalent transition element (M Fe, Al, Cr or La) allows to intercalate a more important amount of lithium and to improve the behaviour of the material during cycling. These materials of M{sub 0.11}V{sub 2}O{sub 5.16} formula are obtained by sol-gel synthesis. the electrochemical study of the Fe compound has shown that it is a mixed oxide with a behaviour similar to V{sub 2}O{sub 5}. The maximum capacity is of about 2 F/mole in the case of Fe, Al and Cr compounds and of about 1.7 F/mole in the case of La. The structural evolution of the Fe compound has been followed during the chemical insertion of Li and the same succession of ...
The school building complex Waterland in The Hague, Netherlands, was built with a hybrid ventilation system. The indoor environment and energy consumption were monitored for one year. Air quality and thermal comfort are of a high quality and the consumption of energy for heating is circa 35% lower than normal. The Waterland project was one of eight demonstration projects, carried out within the framework of the ECBS-Annex 35: Hybrid ventilation in New and retrofitted Office Buildings. ECBS stands for the IEA-program Energy Conservation in Buildings and Community Systems. [Dutch] In ECBCs-annex 35 (ECBS staat voor het IEA-programma Energy Conservation in Buildings and Community Systems) is uitgebreid onderzoek gedaan naar hybride ventilatiesystemen in kantoren en scholen. Dit project heeft geleid tot acht internationale voorbeeldprojecten, waarvan scholencomplex Waterland te Den Haag er een van is. Het scholencomplex is in 2003 opgeleverd met een hybride ventilatiesysteem. Het ...
This research has two main goals. First, we wanted to introduce optimization tools in the diffusion code DONJON, mostly for fuel management. The second objective is more practical. The optimization capabilities are applied to the fuel management problem for different CANDU reactors at refueling equilibrium state. Two kinds of approaches are considered and implemented in this study to solve optimization problems in the code DONJON. The first methods are based on gradients and on the quasi-linear mathematical programming. The method initially developed in the code OPTEX is implemented as a reference approach for the gradient based methods. However, this approach has a major drawback. Indeed, the starting point has to be a feasible point. Then, several approaches have been developed to be more general and not limited by the initial point choice. Among the different methods we developed, two were found to be very efficient: the multi-step method and the mixte method. The second kind of ...
The development of rechargeable lithium batteries with a high mass capacity, made with non-toxic and low cost materials is an important industrial challenge. Morphological and structural modifications occurring in the electrode materials during charge-output cycles should not lower the electrochemical characteristics and the cycling properties of the battery. Thus the structure of electrode materials must be sufficiently deformable and stable to support the constraints linked with lithium intercalation and de-intercalation (ions and electrons absorption/extraction). The aim of this work is to explain some characteristics (mass capacity, ions and electrons mobility, cycling) using the relation between some mechanisms of lithium insertion (sites occupation, lattice reduction mods) and the nature of atoms and chemical bonds (covalence, ionicity). This approach is developed on 2-D models of crystallized and vitreous sulfur compounds (CdI{sub 2} type) with a large inter-sheet distance, and ...
On the 28{sup th} of May in 1998, the regulation of the ''Application of roof bolt support in coal mines'' came into force. Afterwards, the new roof bolt permission guidelines have been worked out by the Landesoberbergamt (Inspectorate of mines) in co-operation with the Deutsche Montan Technologie GmbH, with the Deutsche Steinkohle AG and with bolt manufacturers. These guidelines have been put into force on the 31{sup st} of August in 2000. Topics of this paper are the new regulation and first experiences. (orig.) [German] Nach der Erarbeitung der ''Richtlinien ueber die Verwendung von Ankerausbau im Steinkohlenbergbau (Anker-Richtlinien)'' vom 28. Mai 1998 wurden unverzueglich auch die ''Richtlinien ueber die Genehmigung von Ankerausbau (Ankergenehmigungs-Richtlinien)'' in Angriff genommen. Diese Richtlinien, die das Landesoberbergamt NRW gemeinsam mit Fachleuten der Deutschen ...
The ECOTEC combustion system and the architecture of the new Opel 2.2 l aluminum engine have been configured to achieve low noise and exhaust emissions. This power unit, employed in Germany for the first time in the Astra Coupe, already complies with the Euro IV emissions standard. It features minimum maintenance requirements and a long operating life. The DOHC spark-ignition engine with four valves per cylinder has two chain-driven camshafts, valve gear with roller cam followers and hydraulic lash adjusters. Two chain driven balancer shafts have been integrated into the engine block. The cylinder head and block, lower crankcase, oil pan, and cylinder head cover are all made of aluminum. A modular concept makes it possible to adapt the engine effectively to different vehicle concepts and markets. (orig.) [German] Das ECOTEC-Verbrennungssystem und die Motorarchitektur des neuen 2,2-l-Aluminium-Triebwerks von Opel sind auf niedrige Geraeusch- und Abgasemissionen ...
The ERICAM model (Environmental Risk Internalization through Capital Markets) includes the capital markets as a source contributing to the coverage of risks due to nuclear activites, thus enhancing the effectiveness and functions of the nuclear liability law. The model proposed will allow higher amounts for compensation and will increase financial security, flow of information, and efficient use of resources. The implementation of the model can be achieved on the financing side by issuing Nuke bonds, linking accident-specific options to government bonds. This will essentially increase the risk coverage compared to present means, and will be a pin-pointed addition to the existing layer system. There are three institutions proposed to act as mediators in the implementation of the model: A government authority to supervise the trade in Nuke bonds. Risk-bearing associations in oder to enhance the model`s efficiency, and to reduce transaction costs. Rating agencies that will reduce the ...
The study presented in this thesis is a contribution about the analysis of failures modes of electrolytic capacitors and thyristors. The studied components are main elements of the protection system of the superconductive magnets of the LHC. The study of the ageing of the electrolytic capacitors has shown that their reliability is strongly related to their technological characteristic. Evolution of their principal indicator of ageing (ESR) can be modeled according to different laws chosen according to their running mode. It appears that the prediction of failure of these components other than that due to wear can be only statistical taking into account the many causes of failure involving various modes of failure. In order to be able to evaluate influence of the ageing of the electrolytic capacitors on a system, simple models taking into account this parameters as well as the effective temperature of the component are proposed. An acceptable precision taking into account the simplicity ...
It is demonstrated that highly dispersed molybdenum sulfide catalysts are prepared by using Mo(CO){sub 6} adsorbed on the support. The structure of ultradispersed molybdenum sulfide is suggested by EXAFS techniques to be different from that of MoS{sub 2}. The TOF of the thiophene HDS is almost invariant with the dispersion of molybdenum sulfide at a high molybdenum dispersion, whereas the TOF of the hydrogenation greatly increases with increasing dispersion. On the basis of the HDS activity and optimum Co/Mo ratio of Co-Mo/Al{sub 2}O{sub 3} catalysts having a variety of molybdenum dispersion fabricated by using carbonyl complexes, it is demonstrated that highly active HDS catalysts are prepared by highly dispersing molybdenum sulfide phases. Edge decorations of molybdenum sulfides by cobalt are suggested for the synergy generation between cobalt and molybdenum sulfides. (orig.) [Deutsch] Unter Verwendung von auf dem Traeger adsorbierten Mo(CO){sub 6} lassen sich hochdispergierte ...
Policy strategies for the promotion of electricity from renewable energy sources differ significantly among the Member States of the European Union with respect to the amount of additional installed capacity as well as concerning the country-specific support costs. The present report aims to assess the effectiveness and the economic efficiency of the support policies in the EU based on both historical experiences and prospective model-based analysis. The main message of the investigation is that the most effective policy instruments tend to be cost-efficient at the same time. In particular, feed-in tariff systems were identified as a successful instrument for supporting renewable energies in terms of effectiveness and efficiency, whereas quota systems still have to prove themselves in practice. (orig.) [German] Bezueglich des Erfolges bei der Foerderung erneuerbarer Energietraeger im Stromsektor bestehen deutliche Unterschiede zwischen den Mitgliedsstaaten der ...
It is necessary to measure strength and creep behavior to guarantee the safe and reliable usage of refractory alloys at extremely high temperatures. In the literature there is very little information available about the properties of Mo-Re alloys at temperatures higher than 1000 C. A special test facility has been designed and built for stress-rupture testing at very high temperatures (up to 3000 C) of refractory metals and alloys in inert atmospheres. - The stress-rupture strength as well as the creep behavior of molybdenum-rhenium alloys with rhenium contents between 41 and 51 wt.% have been determined at temperatures ranging from 1200 to 2000 C, and rupture times of up to 10 hours using this facility. Previous measurements of stress-rupture strength and creep behavior of pure rhenium have been compared with the measurement results of Mo-Re alloys. - The discussion of the values measured is based on metallographic test results and scanning electron microscopy (SEM) images of Mo-Re ...
The typical MRI features of the most common pancreatic diseases, such as pancreatitis and adenocarcinoma of the pancreas, have been established. However, even in these common pancreatic disorders, MRI correlation with the underlying pathology is limited for clinical reasons. We emphasize MR-pathological correlation of inflammatory and neoplastic pancreatic changes, including pancreatitis, adenocarcinoma, acinar cell carcinoma, rare cystic and solid pancreatic neoplasms, and islet cell tumors. By highlighting the correlation of key pathological features with MR findings, a better understanding of the MR appearance of pancreatic pathology can be provided. In addition, MRI may prove a powerful tool in detection and characterization of pancreatic tumors. (orig.) [Deutsch] Das MR-tomographische Erscheinungsbild von Pankreatitiden und Adenokarzinomen des Pankreas, als den haeufigsten Pankreaserkrankungen, ist zwar ausreichend bekannt; allerdings ist selbst bei diesen ...
A process model is presented and used for identifying options for controlling the cupola furnace process and for investigating natural gas substitutes. Fuel substitution will affect temperature curves (i.e. tapping temperatures and melting capacity), outlet temperatures and gas mass flow out of the preheating zone. The contribution presents several process variations to overcome these problems and compares them with the natural gas process. [German] Mit dem Prozessmodell werden zunaechst Moeglichkeiten der Steuerung von Abstichtemperatur und Schmelzleistung, insbesondere unter Beruecksichtigung der Schrottqualitaet (spezifische Oberflaeche a{sub G}), untersucht. Es wird gezeigt, dass das Prozessmodell die Ergebnisse aus der Praxis wiedergibt. Daran anschliessend wird mit dem Prozessmodell die Substitution von Erdgas durch minderwertige Gase untersucht (Brennstoffsubstitution, Ressourcenschonung). Durch die Brennstoffsubstitution veraendern sich die Temperaturverlaeufe und damit auch ...
56 patients with the clinical diagnosis of sprained ankles were investigated. Evaluation of the anterior (AFTL) and posterior fibulotalar ligament (PFTL) was performed with the foot in dorsiflexion (20 ) and of the fibulo calcanear ligament (FCL) in plantarflexion (45 ). Axial T{sub 1}w-SE and T{sub 2}w-TSE images were obtained. Full-length visualisation of ligmaments in one slice and the extent of injury were evaluated. 12 ankle injuries were confirmed by operation. With MRI full-length visualisation of lateral ankle ligaments was possible in 86%. A partial/complete rupture of the AFTL was noticed in 33/64% and of the FCI in 29/39%, and of the PFTL in 27/5%. Sensitivity/specificity of MRI when compared to surgery was 100/100% for injuries of the AFTL, 64/100% for the FCL, and 33/78% for the PFTL. (orig./MG) [Deutsch] 56 Patienten wurden mit der klinischen Diagnose einer frischen Supinationsverletzung des oberen Sprunggelenkes untersucht. Das Lig. talofibulare ...
Water power plants mean the design, configuration, execution and operation of buildings and of hydraulic and electrical machines. Their many types are due to the stages of development and the technical alternatives of the use of waterpower and the associated energy economy aspects. The main points of this work are the use of water power, different hydro-electric powerstations, water collection, machines and electrotechnical equipment. In the 2nd revised edition parts on electrical engineering, environment, minimum water run-off pumped storage plants, small scole plants, economical aspects and finite elements were broadened. It is a comprehensive textbook and technical book for students of civil engineering and particularly suitable for engineers active in the theory and practice of waterpower construction. (orig./GL) [Deutsch] Wasserkraftanlagen bedeuten Planung, Gestaltung, Ausfuehrung und Betrieb von Bauwerken und hydraulischen sowie elektrischen Maschinen. Ihre Typenvielfalt ...
In 1986, following comprehensive preliminary studies, a 17 MW battery energy storage plant was set up in the insular power supply system of Berlin (West) for the purpose of frequency and output control and provision of immediate reserve capacities. The present paper reports on the initial task, and the dimensioning and construction of this large-scale demonstration as well as the costs entailed in this. It also relates the experiences gained with the operation of the battery energy storage plant in its function as a fast-responding control unit and gives an account of its economic efficiency. Recent studies on the economic efficiency of the plant in conditions as they exist in the present interconnected power supply system are presented. Finally the author reports on the experiences gained with individual plant components, i.e., battery, battery periphery, and power converter and quantifies the cost of plant operation, maintenance, and servicing. (orig./HW) [Deutsch] Im Inselnetz von ...
The precipitation of heavy metals as hydroxides is the standard technique for the decontamination of waste water streams polluted by these elements. On the other side, progress in research has been made concerning the biosorption onto dead biomass and bioprecipitation supported by physiologically active bacteria. As the aim of this study, a flexible strategy has been envisaged cleaning a waste water with definite heavy metal load underlying the process mentioned above. Suitable bacteria were enriched and the process was tested in a technical plant. As result, a very high efficiency of heavy metal elimination has been found. The field of application covered by the acquired process is identical with the whole range of the waste water streams polluted by heavy metals. In addition, a second stage may be necessary if there are any further contaminants to be removed. (orig.) [Deutsch] Bei der Reinigung von schwermetallhaltigen Abwaessern ist der derzeitige Stand der Technik gegeben durch die ...
This report presents the results of the BMBF-sponsored project Fundamentals and models for assessing the effect of climate changes on soil, plant development and the crops of an economically significant range of farm products. Its aim was to study, by means of the results obtained for winter wheat, the dependence of plant growth on temperature, radiation and water as well as nutrient supply for other economically important crop types. Building on this, process-oriented, climate-sensitive agricultural ecosystem models for winter rye, winter barley, sugar-beet and winter intercrops were developed, verified and, in some sites, validated. First scenario calculations served to demonstrate the climate sensitivity of these models. (orig./KW) [Deutsch] Im vorliegenden Bericht werden die Ergebnisse des BMBF - Vorhabens `Grundlagen und Modelle zur Abschaetzung von Klimaaenderungen auf den Boden, die Pflanzenentwicklung sowie den verwertbaren Ernteertrag einer wirtschaftlich ...
Background. In multiple myeloma 5 different infiltration patterns can be differentiated: 1. Normal appearance of bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltration, 5. 'salt-and pepper' pattern with inhomogeneous bone marrow with interposition of fat islands. Methods. For the fast and total acquisition of all patterns a combination of a T1-weighted spin echo sequence and a fat suppression technique is superior. The focal involvement is clearly demonstrated as areas of high signal intensity on e.g. STIR images. Diffuse involvement can be quantified objectively by calculation of the percentage of signal intensity increase after contrast material injection. MRI is superior to X-ray in focal and diffuse involvement. With ultrafast sequences a 'screening' of the whole red bone marrow as for myeloma infiltration is possible. Prognosis. In prognosis studies diffuse infiltration is inferior to ...
Purpose: {sup 31}P-MRS is used to assess the influence of sex and age on quadriceps muscle metabolism before and after exercise. Materials and Methods: 32 healthy volunteers (15 women, 17 men; mean age: 38{+-}17 yrs.) were examined by dynamic phosphorus-31 ({sup 31}P) magnetic resonance spectroscopy (MRS). In the magnet, the quadriceps muscle was stressed by an isometric and an isotonic form of exercise until exhaustion, respectively. Results: Resting conditions: With increasing subjects` age, the ratio {beta}-adenosine triphosphate/total phosphate decreased (r=-0.37; p=0.02). With increasing subjects` age, the ratios inorganic phosphate/phosphocreatine (r=0.79; p=5x10{sup -8}), phosphomonoester/{beta}-adenosine triphosphate (r=0.74; p=10{sup -6}) and phosphodiester/{beta}-adenosine triphosphate (r=0.62; p=10{sup -4}) increased. The pH was the only one of the evaluated spectroscopic parameters which showed a sex-dependence: Female subjects had a significantly lower pH (7.03{+-}0.02) ...
Let $C$ be a curve of genus two. We denote by $SU_C(3)$ the moduli space of semi-stable vector bundles of rank 3 and trivial determinant over $C$, and by $J^d$ the variety of line bundles of degree $d$ on $C$. In particular, $J^1$ has a canonical theta divisor $\\Theta$. The space $SU_C(3)$ is a double cover of $P^8=|3\\Theta|$ branched along a sextic hypersurface, the Coble sextic. In the dual $\\check{P}^8=|3\\Theta|^*$, where $J^1$ is embedded, there is a unique cubic hypersurface singular along $J^1$, the Coble cubic. We prove that these two hypersurfaces are dual, inducing a non-abelian Torelli result. Moreover, by looking at some special linear sections of these hypersurfaces, we can observe and reinterpret some classical results of algebraic geometry in a context of vector bundles: the duality of the Segre-Igusa quartic with the Segre cubic, the symmetric configuration of 15 lines and 15 points, the Weddle quartic surface and the Kummer surface.
The contents of this report covers: (1) development of optimal geometries for crowned helical gears; (2) a method for their generation; (3) tooth contact analysis (TCA) computer programs for the analysis of meshing and bearing contact of the crowned helical gears; and (4) modelling and simulation of gear shaft deflection. The developed method for synthesis was used to determine the optimal geometry for a crowned helical pinion surface and was directed to localize the bearing contact and guarantee favorable shape and a low level of transmission errors. Two new methods for generation of the crowned helical pinion surface are proposed. One is based on the application of a tool with a surface of revolution that slightly deviates from a regular cone surface. The tool can be used as a grinding wheel or as a shaver. The other is based on a crowning pinion tooth surface with predesigned transmission errors. The pinion tooth surface can be generated by ...
In the heat exchangers of power plants, scale deposition may occur, especially at the leading edge of contraction. The growth of scale can lead to an increase in pressure and cause oscillation of the water level. In our previous study, the dependence of flow on contraction geometry was analyzed numerically and empirically. It was shown that the contraction ratio of hydraulic diameter of the flow path contributed greatly to the difference in pressure drop and turbulent kinetic energy at the leading edge of the flow path. In this study, the effect of contraction geometry and flow rate on scale adhesion was studied in AVT chemistry at 270degC using a high-velocity scale-adhesion test loop. The differential pressure and the amount of scale deposited due to scale adhesion at the leading edge of the flow path increased more in a quatrefoil-type flow path than in drill-type flow path. The differential pressure and the amount of scale deposited also ...
TART97 is a coupled neutron-photon, 3 dimensional, combinatorial geometry, time dependent Monte Carlo transport code. This code can run on any modern computer. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART97 is also incredibly fast: if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART 97 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART97 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART97 and ist data files.
The investigation of interfaces between thin organic films and metal surfaces is a field of highest interest because it represents the basis for future applications of organic electronic devices. In this context, phtalocyanines are of particular interest since repulsive intermolecular interaction was found recently for this group of organic molecules. Tin(II)-phtalocyanine (SnPc) is non-planar and can adsorb in two different geometries: with the Sn atom pointing downwards (Sn down) or upwards (Sn up). In our group different Pc molecules have previously been studied using several experimental techniques like SPA-LEED or XSW. Here we present STM studies of SnPc on Ag(111), taken at different coverages and temperatures, and discuss the results in the context of our previous findings. At low coverages the formation of chains can be observed for Sn down molecules while Sn up molecules tend to stay separated. This originates from a strong interaction with the substrate ...
To resolve the central thermal safety issue for spent fuel dry storage concrete canister design or Wolsung (CANDU) nuclear power plant unit 1, a thermal analysis method has been developed for the complicated geometry of rod bundles and the multi-dimensional and multi-mode heat transfer phenomena. The canister geometry is simplified and combined heat transfer by conduction, convection, and radiation is considered through effective heat transfer coefficients. Mean temperature distributions of the fuel bundles within the fuel basket are obtained by solving the heat transfer problem using an existing computer code HEATING5. The measured steady state temperature distribution within a mock-up of a storage basket is compared to the calculated result. Steady state and/or transient fuel temperature distributions have been calculated for various ambient conditions at the canister exterior surface.
To resolve the central thermal safety issue for spent fuel dry storage concrete canister design or Wolsung (CANDU) nuclear power plant unit 1, a thermal analysis method has been developed for the complicated geometry of rod bundles and the multi-dimensional and multi-mode heat transfer phenomena. The canister geometry is simplified and combined heat transfer by conduction, convection, and radiation is considered through effective heat transfer coefficients. Mean temperature distributions of the fuel bundles within the fuel basket are obtained by solving the heat transfer problem using an existing computer code HEATING5. The measured steady state temperature distribution within a mock-up of a storage basket is compared to the calculated result. Steady state and/or transient fuel temperature distributions have been calculated for various ambient conditions at the canister exterior surface.
Several configurations of moderating and shielding materials have been designed and measured on the LVR-15 reactor for boron neutron capture therapy (BNCT) purposes. To determine the neutron and gamma ray space-energy distributions in the cylindrical geometry, the two-dimensional code DOT with the coupled neutron-gamma data library DLC-36 was used. The experimental verification of the beam parameters was performed in the LVR-15 reactor thermal column empty space with layers of graphite, aluminium, alumina, lead and bismuth. Attention was paid to establishing techniques and instrumentation for monitoring the neutron and gamma ray dose and beam quality. The thermal and epithermal flux densities were measured by activation foils, the neutron spectrum was determined with a Bonner spectrometer and gamma ray background with a scintillation spectrometer. The distribution of thermal neutrons in the human head phantom was mapped with a small semiconductor detector (Si[sup ...
Several configurations of moderating and shielding materials have been designed and measured on the LVR-15 reactor for boron neutron capture therapy (BNCT) purposes. To determine the neutron and gamma ray space-energy distributions in the cylindrical geometry, the two-dimensional code DOT with the coupled neutron-gamma data library DLC-36 was used. The experimental verification of the beam parameters was performed in the LVR-15 reactor thermal column empty space with layers of graphite, aluminium, alumina, lead and bismuth. Attention was paid to establishing techniques and instrumentation for monitoring the neutron and gamma ray dose and beam quality. The thermal and epithermal flux densities were measured by activation foils, the neutron spectrum was determined with a Bonner spectrometer and gamma ray background with a scintillation spectrometer. The distribution of thermal neutrons in the human head phantom was mapped with a small semiconductor detector (Si"6Li). ...
We investigate some aspects of the radiation damage mechanisms in biomolecules, focusing on the modelling of resonant fragmentation caused by the attachment of low-energy electrons (LEEs) initially ejected by biological tissues when exposed to ionizing radiation. Scattering equations are formulated within a symmetry-adapted, single-center expansion of both continuum and bound electrons, and the interaction forces are obtained from a combination of ab initio calculations and a nonempirical model of exchange and correlation effects developed in our group. We present total elastic scattering cross-sections and resonance features obtained for the equilibrium geometries of glycine, alanine, proline and valine. Our results at those geometries of the target molecules are briefly shown to qualitatively explain some of the fragmentation patterns obtained in experiments. We further carry out a one-dimensional (1D) modeling for the dynamics of ...
Understanding the influence of interfacial structures on the nanoarchitecture mechanical properties is of particular importance for its mechanical applications. Due to a small size of constituting nanostructural units and a consequently high volume ratio of such interfacial regions, this question becomes crucial for the overall mechanical performance. Boron nitride bamboo-like nanotubes, called hereafter boron nitride nanobamboos (BNNBs), are composed of short BN nanotubular segments with specific interfaces at the bamboo-shaped joints. In this work, the mechanical properties of such structures are investigated by using direct in situ transmission electron microscopy tensile tests and molecular dynamics simulations. The mechanical properties and deformation behaviors are correlated with the interfacial structure under atomic resolution, and a geometry strengthening effect is clearly demonstrated. Due to the interlocked joint interfacial structures and compressive ...
Swirling speed in a direct injection diesel engine was measured by a laser doppler velocimeter. Intake port geometry and engine speed were changed as factors affecting the swirling flow to study the distribution of swirling flow speed. The distribution of swirling flow speed changes complicatedly owing to axial nonsymmetry during intake process but becomes simple shape of axial symmetry during compression process after closing intake valve. But if this is assumed as the rigid swirl shape, the difference due to each intake port cannot be expressed but also large error may be possible to appear close to the cylinder wall. The distribution of swirling flow speed during compression process changes similarly, nearly proportinal to engine speed. But the similarity is higher at the middle period in compression process than at the end period in compression period. Axial distribution of local swirling ratio during compression process is nearly uniform. 8 refs., 10 figs., 1 ...
Context. The I(15.01 A)/I(16.78 A) emission line intensity ratio in Fe XVII has been reported to deviate from its theoretical value in solar and stellar X-ray spectra. This is attributed to opacity in the 15.01 A line, leading to a reduction in its intensity, and was interpreted in terms of a geometry in which the emitters and absorbers are spatially distinct. Aims. We study the I(15.01 A)/I(16.78 A) intensity ratio for the active cool dwarf EV Lac, in both flare and quiescent spectra. Methods. The observations were obtained with the Reflection Grating Spectrometer on the XMM-Newton satellite. The emission measure distribution versus temperature reconstruction technique is used for our analysis. Results. We find that the 15.01 A line exhibits a significant enhancement in intensity over the optically thin value. To our knowledge, this is the first time that such an enhancement has been detected on such a sound statistical basis. We interpret this enhancement in ...
Large area, single-element Si(Li) detectors have been fabricated using a novel geometry which yields detectors with reduced capacitance and hence reduced noise at short amplifier pulse-processing times. A typical device employing the new geometry with a thickness of 6 mm and an active area of 175 mm 2 has a capacitance of only 0.5 pf, compared to 2.9 pf for a conventional planar device with equivalent dimensions. These new low capacitance detectors, used in conjunction with low capacitance field effect transistors, will result in x-ray spectrometers capable of operating at very high count rates while still maintaining excellent energy resolution. The spectral response of the low capacitance detectors to a wide range of x-ray energies at 80 K is comparable to typical state-of-the-art conventional Si(Li) devices. In addition to their low capacitance, the new devices offer other advantages over conventional detectors. Detector fabrication ...
In a holomorphic family $(X_b)_{b\\in B}$ of non-K\\"ahlerian compact manifolds, the holomorphic curves representing a fixed 2-homology class do not form a proper family in general. The deep source of this fundamental difficulty in non-K\\"ahler geometry is the {\\it explosion of the area} phenomenon: the area of a curve $C_b\\subset X_b$ in a fixed 2-homology class can diverge as $b\\to b_0$. This phenomenon occurs frequently in the deformation theory of class VII surfaces. For instance it is well known that any minimal GSS surface $X_0$ is a degeneration of a 1-parameter family of simply blown up primary Hopf surfaces $(X_z)_{z\\in D\\setminus\\{0\\}}$, so one obtains non-proper families of exceptional divisors $E_z\\subset X_z$ whose area diverge as $z\\to 0$. Our main goal is to study in detail this non-properness phenomenon in the case of class VII surfaces. We will prove that, under certain technical assumptions, a lift $\\widetilde E_z$ of $E_z$ in the ...
A brief description of a method for producing relatively intense molecular negative ion beams for the difficult Group IIA elements is given which offers considerable improvement in terms of source operation and beam intensity stability over other methods conventionally utilized. It is particularly suited for use in cesium plasma sources such as the Aarhus geometry and axial geometry versions of the source. The method utilizes H/sub 2/ source feed gas for the production of a hydrogen-rich plasma discharge which sputters a negatively biased probe made of elemental or copper alloy material. Negative ion beams of MgH/sub 3//sup -/>=12 ..mu.. A have been realized during routine operation of the 25 MV tandem accelerator. Negative ion beam intensity data, typical source operational parameters, and examples of mass spectra associated with their production are given. Interesting intermetallic molecular negative ion beams consisting of the particular ...
A numerical investigation of the mixing of gaseous uranium and hydrogen inside an open-cycle gas core nuclear rocket engine (spherical geometry) is presented. The gaseous uranium fuel is injected near the centerline of the spherical engine cavity at a constant mass flow rate, and the hydrogen propellant is injected around the periphery of the engine at a five degree angle to the wall, at a constant mass flow rate. The main objective is to seek ways to minimize the mixing of uranium and hydrogen by choosing a suitable injector geometry for the mixing of light and heavy gas streams. Three different uranium inlet areas are presented, and also three different turbulent models (k-var-epsilon model, RNG k-var-epsilon model, and RSM model) are investigated. The commercial CFD code, FLUENT, is used to model the flow field. Uranium mole fraction, axial mass flux, and radial mass flux contours are obtained. copyright 1997 American Institute of Physics.
A new double-null, slotted divertor configuration will be installed for the DIII-D Radiative Divertor Program at General Atomics in late 1996. Four cryocondensation pumps, three new and one existing, will be part of this new divertor. The purpose of the pumps is to provide plasma density control and to limit the impurities entering the plasma core by providing pumping at each divertor strike point. The three new pumps are based on the design of the existing pump, installed in 1992 as part of the Advanced Divertor Program. The pump continues to operate successfully. The new pumps require geometry modifications to the original design. Therefore, extensive modal and dynamic analyses were performed to determine the behavior of these pumps and their helium and nitrogen feed lines during disruption events. Thermal and fluid analyses were also performed to characterize the helium two-phase flow regime in the pumps and their feedlines. A flow testing program was completed ...
A new double-null, slotted divertor configuration will be installed for the DIII-D Radiative Divertor Program at General Atomics in late 1996. Four cryocondensation pumps, three new and one existing, will be part of this new divertor. The purpose of the pumps is to provide plasma density control and to limit the impurities entering the plasma core by providing pumping at each divertor strike point. The three new pumps are based on the design of the existing pump, installed in 1992 as part of the Advanced Divertor Program. The new pumps require geometry modifications to the original design. Therefore, extensive modal and dynamic analyses were performed to determine the behavior of these pumps and their helium and nitrogen feed lines during disruption events. Thermal and fluid analyses were also performed to characterize the helium two-phase flow regime in the pumps and their feedlines. A flow testing program was completed to test the change in ...
A new double-null, slotted divertor configuration will be installed for the DIII-D Radiative Divertor Program at General Atomics in late 1996. Four cryocondensation pumps, three new and one existing, will be part of this new divertor. The purpose of the pumps is to provide plasma density control and to limit the impurities entering the plasma core by providing pumping at each divertor strike point. The three new pumps are based on the design of the existing pump, installed in 1992 as part of the Advanced Divertor Program. The pump continues to operate successfully. The new pumps require geometry modifications to the original design. Therefore, extensive modal and dynamic analyses were performed to determine the behavior of these pumps and their helium and nitrogen feed lines during disruption events. Thermal and fluid analyses were also performed to characterize the helium two-phase flow regime in the pumps and their feedlines. A flow testing program was completed ...
The authors have designed and constructed four types of electron-beam diodes for the new 4-MV RLA injector: a non-immersed foilless diode, a magnetically immersed foilless diode, a foil diode and an ion-focused foilless diode, They are tailored to fit the new injector cavity. The design goals were to produce high quality 10-kA to 20-kA electron beams with a #beta# perpendicular smaller than 0.2 and a beam radius of the order of 2 cm. These beams will be matched to the RLA IFR channel so #beta# perpendicular must be equal to or smaller than the square root of the ratio of the beam current versus Alfven current for f_e = 1. A reentrant anode geometry was selected for the injector cavity design, because it offers substantial savings on the required amount of feromagnetic cores. The inner radius of the outside shell, now only 30 cm, would have been twice as large (60 cm) if a coaxial non-reentrant geometry had been adopted. The shape of the anode ...
As part of a larger elastic numerical modeling project, we have been investigating how energy reflected from steeply dipping interfaces is recorded using typical multicomponent acquisition geometries. Specifically, we have been interpreting how rcflection events from the flanks of salt dome structures are distributed on 3C and 4C phones for vertical seismic profiles (VSPs) and ocean bottom seismic (OBS) or land surface surveys. The ultimate goal of this investigation is to improve the structural imaging of steeply dipping interfaces and eventually to evaluate the usc of the recorded elastic wavefield for fluid description near these interfaces. In the current work, we focus on a common assumption used when processing converted wave reflection seismic data that most PP energy is recorded on the vertical geophone and/or the hydrophone and that most PS energy is recorded on the horizontal geophones. This is a useful assumption when it is valid, because it eliminates ...
A study has been performed of the initial corrosion of support structure alloys in crevices of various geometries, when galvanically coupled to alloy 600. Corrosion rates were monitored continuously by measuring the galvanic current flowing in each couple, transduced by a zero impedance ammeter. Experiments were performed in a single-pass flowing electrolyte system, with AVT water pumped through alloy 600 tubing past the orifice of each crevice. Fourteen crevices were studied simultaneously in two parallel flow arms containing seven specimens each. The steady state AVT water pH/hydrazine/oxygen concentrations were controlled by microcomputer, allowing the effect of secondary water chemistry on the corrosion rate to be studied easily. Control of the crevice electrolyte composition was achieved by separately pumping electrolyte, at a low rate, directly into the crevices of the seven specimens in the lower flow arm. In addition, a high pressure syringe was used to ...
The University of Georgia, in collaboration with GE Global Research, has investigated the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs. The final goal of the project was the design and fabrication of a high-efficacy white light UV-LED device through improved geometry and optimized phosphor coatings. At the end of the research period, which was extended to seamlessly carry over the research to a follow-up program, we have demonstrated a two-fold improvement in the conversion efficiency of a white light LED device, where the increase efficacy is due to both improved phosphor quantum efficiency and lamp geometry. Working prototypes have been displayed at DOE sponsored meetings and during the final presentation at the DOE Headquarters in Washington, DC. During the first phase of the project, a fundamental understanding of quenching processes in UV-LEDs was obtained, and the relationships that ...
The University of Georgia, in collaboration with GE Global Research, has investigated the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs. The final goal of the project was the design and fabrication of a high-efficacy white light UV-LED device through improved geometry and optimized phosphor coatings. At the end of the research period, which was extended to seamlessly carry over the research to a follow-up program, we have demonstrated a two-fold improvement in the conversion efficiency of a white light LED device, where the increase efficacy is due to both improved phosphor quantum efficiency and lamp geometry. Working prototypes have been displayed at DOE sponsored meetings and during the final presentation at the DOE Headquarters in Washington, DC. During the first phase of the project, a fundamental understanding of quenching processes in UV-LEDs was obtained, and the relationships that ...
We compared experimental wave aberrations in pseudophakic eyes with aspheric intraocular lenses (IOLs) to simulate aberrations from numerical ray tracing on customized computer eye models using corneal topography, angle ?, ocular biometry, IOL geometry, and IOL tilt and decentration measured on the same eyes. We found high correlations between real and simulated aberrations even for the eye with only the cornea, and these increased on average when the IOL geometry and position were included. Relevant individual aberrations were well predicted by the complete eye model. Corneal spherical aberration and horizontal coma were compensated by the IOL, and in 58.3% of the cases IOL tilt and decentration contributed to compensation of horizontal coma. We conclude that customized computer eye models are a good representation of real eyes with IOLs and allow understanding of the relative contribution of optical, geometrical and surgically-related factors ...
The piston bowl design is one of the most important factors that affect the air-fuel mixing and the subsequent combustion and pollutant formation processes in a direct-injection diesel engine. The bowl geometry and dimensions, such as the pip region, bowl lip area, and toroidal radius, are all known to have an effect on the in-cylinder mixing and combustion process. In order to understand better the effect of re-entrant geometry, three piston bowls with different toroidal radii and lip shapes were investigated using computational fluid dynamics engine modelling. KIVA3V with improved submodels was used to model the in-cylinder flows and combustion process, and it was validated on a high-speed direct-injection engine with a second-generation common-rail fuel injection system. The engine's performance, in-cylinder flow, and combustion, and emission characteristics were analysed at maximum power and maximum torque conditions and at ...
This report surveys the possibilities and restrictions of different construction materials for the purpose of the blades of a small stall regulated turbine. For example scaling up, material saving at decreasing of static or dynamic loads, comparisons of global costs based on prices per unit of weight, etc. For the mutual comparison of construction materials for turbine blades the starting point is a stall regulated horizontal axis turbine with a rotor diameter of 16 m and a tipvane speed of about 64 m/s. Short descriptions are given of the materials and of the applied production methods with the resulting blade geometry. The blade skins are dimensionized for storm loads after the optimalization of the blade geometry, needed for the design wind speed, is recorded. The resulting blade skins are mutually compared as for weight, mass inertia and bending stiffness. Also a comparison took place of the resulting reserve factors against load variations ...
The results of experimental measurements and theoretical simulations of circular dichroism in the angular distribution (CDAD) of photoemission from atomic core levels of each of the enantiomers of a chiral molecule, alanine, adsorbed on Cu(1 1 0) are presented. Measurements in, and out of, substrate mirror planes allow one to distinguish the CDAD due to the chirality of the sample from that due to a chiral experimental geometry. For these studies of oriented chiral molecules, the CDAD is seen not only in photoemission from the molecular chiral centre, but also from other atoms which have chiral geometries as a result of the adsorption. The magnitude of the CDAD due to the sample chirality differs for different adsorption phases of alanine, and for different emission angles and energies, but is generally small compared with CDAD out of the substrate mirror planes which is largely unrelated to the molecular chirality. While similar measurements ...
The stability of a solid ice cover subjected to rapidly varying water levels and discharge was investigated. The support from the bank limits the stress in the ice cover and consequently bank contact must be maintained to ensure ice cover stability. An analysis was required of the stability of ice hinges, a flexible connection between a solid ice cover and the riverbank. Phase II and phase III of the research involved a field study of the Peace River, investigating the evolution of ice hinges with water level variation, from initial ice cover cracking parallel to the banks, to a fully developed hinge. A test program of midwinter discharge variations was undertaken to gather specific data and measurements of ice hinge link length, ice thickness, hinge joint behavior, riverbank geometry, and response of ice hinging to water level variation. As a result of the program, concepts developed throughout the study were confirmed, preliminary guidelines for hydroelectric ...
The goal of assembly sequencing is to plan a feasible series of operations to construct a product from its individual parts. Previous research has thoroughly investigated assembly sequencing under the assumption that parts have nominal geometry. This paper considers the case where parts have toleranced geometry. Its main contribution is an efficient procedure that decides if a product admits an assembly sequence with infinite translations that is feasible for all possible instances of the components within the specified tolerances. If the product admits one such sequence, the procedure can also generate it. For the cases where there exists no such assembly sequence, another procedure is proposed which generates assembly sequences that are feasible only for some values of the toleranced dimensions. If this procedure produces no such sequence, then no instance of the product is assemblable. Finally, this paper analyzes the relation between ...
The present paper is concerned with development and application of a so-called Effective Convection Model (ECM), which aims to provide a detailed, mechanistic description of heat transfer processes in a BWR lower plenum. The ECM is a Computational Fluid Dynamics (CFD)-like tool which employs a simpler and more effective approach to compute heat transfer by solving only energy conservation equation instead of solving the full set of Navier-Stokes and energy equations by a CFD code. We implement the ECM in a CFD code (Fluent), with detailed description of the ECM development, implementation and validation. A dual approach is used to validate the ECM, namely validation against experimental data and against heat transfer results obtained by CFD predictions in the same geometries and conditions. Insights gained from CFD simulations are also used to improve ECM. The ECM capability as an effective tool to simulate heat transfer of an internally heated volume in ...
The present paper is concerned with development and application of a so-called Effective Convection Model (ECM), which aims to provide a detailed, mechanistic description of heat transfer processes in a BWR lower plenum. The ECM is a Computational Fluid Dynamics (CFD)-like tool which employs a simpler and more effective approach to compute heat transfer by solving only energy conservation equation instead of solving the full set of Navier-Stokes and energy equations by a CFD code. We implement the ECM in a CFD code (Fluent), with detailed description of the ECM development, implementation and validation. A dual approach is used to validate the ECM, namely validation against experimental data and against heat transfer results obtained by CFD predictions in the same geometries and conditions. Insights gained from CFD simulations are also used to improve ECM. The ECM capability as an effective tool to simulate heat transfer of an internally heated volume in ...
Analyzed are methods for optimizing productivity of coal surface mining systems which consist of bucket wheel excavators, belt conveyors, and dumping conveyors. System productivity depends on adjustment of belt conveyor capacity to productivity of bucket wheel excavators. Factors which influence productivity of bucket wheel excavators are analyzed: dimensions and geometry of bucket wheels, rated power of drive systems for bucket wheels and properties of mined materials (coal or overburden). Indices used in Czechoslovakia for assessing productivity of bucket wheel excavators are compared. Factors which influence capacity of belt conveyors are also analysed: belt dimensions, belt geometry, angle of repose of hauled coal or overburden, and haulage speed of a belt conveyor. Investigations carried out in brown coal surface mines in Czechoslovakia show that conveyor capacity should exceed productivity of bucket wheel excavators. In the majority of ...
In studying the dynamics of large N_c SU(N_c) gauge theory with fundamental quark flavours in the quenched approximation, we observe a novel phase transition at finite temperature. A quark condensate forms at finite quark mass, and the value of the condensate varies smoothly with the quark mass for generic region in parameter space. At a particular value of the quark mass, there is a finite discontinuity in the condensate's vacuum expectation value, corresponding to a first order phase transition. We study this using holography, the string dual being the geometry of N_c D3--branes at finite temperature, AdS_5-Schwarzschild times S^5, probed by a D7-brane. The D7-brane has topology R^4 times S^3 times S^1, and allowed solutions correspond to either the S^3 or the S^1 shrinking away in the interior of the geometry. The phase transition represents a jump between branches of solutions having these two distinct D-brane topologies and the transition ...
A vortex diode has been developed as a reverse flow limiter in the primary circuit of an advanced gas cooled reactor. In addition to the development work on a prototype diode to optimise performance and geometry, measurements were also made on an available experimental diode of similar size with pressure differences up to 4 MPa and temperatures up to 600 K using nitrogen, argon and carbon dioxide as the test fluids. Correlation of data from all tests was satisfactorily obtained using isentropic one-dimensional nozzle flow equations. (author).
The thesis gives an overview of the validation process for thermal-hydraulic system codes and it presents in more detail the assessment and validation of the French code CATHARE for VVER calculations. Three assessment cases are presented: loop seal clearing, core reflooding and flow in a horizontal steam generator. The experience gained during these assessment and validation calculations has been used to analyze the behavior of the horizontal steam generator and the natural circulation in the geometry of the Loviisa nuclear power plant. Large part of the work has been performed in cooperation with the CATHARE-team in Grenoble, France. (41 refs., 11 figs., 8 tabs.).
Natural convection of vaporizing Deuterium at 25 K transports the heat generated in the moderator cell of the cold neutron source to a He cooled condenser. The thermohydraulics of this thermosiphon were precalculated and the results verified by experiments in a 1:1 model using D_2 as fluid. The experimental results show that the thermosiphon operates stable. The demanded liquid content of the cell as well as wall temperatures below 50 K can be ensured by a proper design of the cell outlet flow geometry. A 7 min. loss of cryogenic power results in transient temperatures of the cell wall of not more than 300 K.
The pH of the solution is shown to significantly effect the reflection anisotropy spectroscopy (RAS) profiles of adenine adsorbed at Au(110)/electrolyte interfaces. At pH 12.8 the net adsorption is very weak due the formation of negative adenine ions in solution. The sensitivity of the RAS profiles to the pH of the solution is probably due to a change in the geometry of the adsorbed molecules caused by a disruption of the base stacking configuration that is adopted when adenine is adsorbed from solutions at pH 7.1. (Abstract Copyright [2010], Wiley Periodicals, Inc.)
Stable quotient spaces provide an alternative to stable maps for compactifying spaces of maps. When the target is projective space and the domain curve has genus 1, these are smooth proper Deligne-Mumford stacks. In this paper we study the associated coarse moduli schemes. We show these schemes are projective, rationally connected and have Picard number 2. Then we give generators for the Picard group, compute the canonical divisor, and the cones of ample and effective divisors. In certain cases, we also give a closed formula for the Poincar\\'{e} polynomial.
A car-borne NaI(Tl) spectrometric system was used together with a {sup 137}Cs source to obtain realistic data in the search for unshielded and semi-shielded orphan sources. The potassium-stripped counts (PSC) method was used to estimate the influence by the shielding on the detection ability. A reduction of about 5% in the critical distance was obtained for the semi-shielded source. A curve fitting method was also developed and evaluated. Results from the curve fitting method showed inferior ability to find the source compared to the PSC method. However, it can be a useful complementary tool, for characterisation of the source shielding, and estimation of the distance from the road.
A car-borne NaI(Tl) spectrometric system was used together with a "1"3"7Cs source to obtain realistic data in the search for unshielded and semi-shielded orphan sources. The potassium-stripped counts (PSC) method was used to estimate the influence by the shielding on the detection ability. A reduction of about 5% in the critical distance was obtained for the semi-shielded source. A curve fitting method was also developed and evaluated. Results from the curve fitting method showed inferior ability to find the source compared to the PSC method. However, it can be a useful complementary tool, for characterisation of the source shielding, and estimation of the distance from the road.
The applications of neutron reflectometry to study dynamic phenomena at surface and interfaces have been restricted so far. This was mainly due to the low intensity of neutron sources, but now high-intensity spallation neutron sources are under construction in Japan (J-PARC) and US (SNS). We are planning to install a spin-echo option on the J-PARC neutron reflectometer with horizontal sample geometry for studies of dynamics of surfaces and interfaces. This option is based on the resonance spin-echo method and aimed at dynamics up to hundreds of nanoseconds. In this contribution, the plan and status of development are introduced together with the principle and characteristics of this option.
This paper reports progress in the fabrication and characterization of an array of 1nm-scale colloidal particles (i.e., quantum-dot array) that can be operated to execute nontrivial and innovative computations, possibly including quantum logic. We discuss the actual fabrication of 2-nm metal clusters as an example of possible quantum dot implementation. Innovative and unconventional paradigms underlie the different stages of this work. For example, regular array geometry is achieved by directing appropriately derivatized metal clusters to preselected locations along a stretched strand of an engineered DNA sequence.
CANDU 600 nuclear reactors are usually fuelled with STANDARD (STD), 37 rods fuel bundles. Natural uranium (NU) dioxide (UO_2), is used as fuel composition. A new fuel bundle geometry called CANFLEX (CFX) with 43 rods is proposed and some new fuel composition are considered. Flexibility is the key word for the attempt to use some different fuel geometries and compositions for CANDU 600 nuclear reactors as well as for innovative ACR-700/1000 nuclear reactors. The fuel bundle considered in this paper is CFX-RU-0.90 that encodes the CANFLEX geometry, recycled dioxide uranium (RU) with 0.90% enrichment. The goal of this proposal is ambitious: a higher average discharge burn-up up to 14000 MWd/tU and, for the same amount of generated electric power, reduction in nuclear fuel fabrication, reduction of spent nuclear fuel radioactive waste and reduction of refueling operational work by using fewer bundles. An improved sub-channel ...
Extensive experimental and analytical investigations of fluid flow and heat transfer in gas-cooled rod bundles have been carried out. Different bundle geometries with partially or fully roughened rod surfaces were tested in a carbon dioxide loop. An advanced and comprehensive measuring control and instrumentation are important design features of this experiment. Comprehensive thermal hydraulic subchannel analysis computer codes have been developed in order to assist fuel element design calculation for gas-cooled reactors. The experiments, codes and their verification procedure are described and the results of comparisons between measured and calculated pressure and temperature distributions are given. (orig.).
A pre-stack migration algorithm for elastic waves in two-dimensional variable-velocity media is developed, implemented, and tested. The algorithm operates in the time-space domain and is based on reverse-time finite-difference extrapolation of elastic waves. The algorithm is explained and demonstrated in the context of imaging of elastic vertical seismic profile data, but is applicable to any source-recorder geometry. Synthetic test examples include a point diffractor, laterally homogeneous layers, and the flank of a salt dome.
In the present work the geometry of annular ducts with asymmetrical longitudinal fins is optimized in order to enhance the heat transfer under laminar coolant flow conditions. The heat transferred is also maximized for a given amount of material or hydraulic resistance. Polynomial profiles are assigned to the two lateral fin surfaces. Velocity and temperature distributions on the annular duct cross section are determined with the help of a finite-element model. A global heat transfer coefficient and an equivalent Nusselt number are then calculated. Lastly, optimum asymmetrical fins obtained by means of a genetic algorithm are shown for different situations and their performance is compared with those of optimum symmetrical fins.
Three-dimensional magnetohydrodynamic simulations are executed in a full toroidal geometry to clarify the physical mechanisms of the Internal Reconnection Event (IRE), which is observed in the spherical tokamak experiments. The simulation results reproduce several main properties of IRE. Comparison between the numerical results and experimental observation indicates fairly good agreements regarding nonlinear behavior, such as appearance of localized helical distortion, appearance of characteristic conical shape in the pressure profile during thermal quench, and subsequent appearance of the m=2/n=1 type helical distortion of the torus. (author)
The Monte Carlo ray-tracing method is applied and coupled with optical properties to predict the radiation performance of solar concentrator/cavity receiver systems. Several different cavity geometries are compared on the radiation performance. A flux density distribution measurement system for dish parabolic concentrators is developed. The contours of the flux distribution for target placements at different distances from the dish vertex of a solar concentrator are taken by using an indirect method with a Lambert and a charge coupled device (CCD) camera. Further, the measured flux distributions are compared with a Monte Carlo-predicted distribution. The results can be a valuable reference for the design and assemblage of the solar collector system.
We present a numerical method for computing diffusive transport on a surface derived from image data. Our underlying discretization method uses a Cartesian grid embedded boundary method for computing the volume transport in region consisting of all points a small distance from the surface. We obtain a representation of this region from image data using a front propagation computation based on level set methods for solving the Hamilton-Jacobi and eikonal equations. We demonstrate that the method is second-order accurate in space and time, and is capable of computing solutions on complex surface geometries obtained from image data of cells.
Noncommutative tori are among historically the oldest and by now the most developed examples of noncommutative spaces. Noncommutative Yang-Mills theory can be obtained from string theory. This connection led to a cross-fertilization of research in physics and mathematics on Yang-Mills theory on noncommutative tori. One important result stemming from that work is the link between T-duality in string theory and Morita equivalence of associative algebras. In this article we give an overview of the basic results in differential geometry of noncommutative tori. Yang-Mills theory on noncommutative tori, the duality induced by Morita equivalence and its link with the T-duality are discussed. Noncommutative Nahm transform for instantons is introduced.
The authors have measured the noise of MOS transistors of the United Technology Microelectronics Center (UTMC) 1.2 [mu]m radiation hardened CMOS P-well process from the weak to moderate inversion region. The noise power spectral densities of both NMOS and PMOS devices were measured from 1 KHz to 50 MHz. The bandwidth was chosen such that the important components of the spectral densities such as the white thermal noise and the 1/f noise could be easily resolved and analyzed in detail. In this paper the effects of different device terminal DC biases and channel geometries on the noise are described.
Current multi-scale computational models of ventricular electromechanics describe the full process of cardiac contraction on both the micro- and macro- scales including: the depolarization of cardiac cells, the release of calcium from intracellular stores, tension generation by cardiac myofilaments, and mechanical contraction of the whole heart. Such models are used to reveal basic mechanisms of cardiac contraction as well as the mechanisms of cardiac dysfunction in disease conditions. In this paper, we present a methodology to construct finite element electromechanical models of ventricular contraction with anatomically accurate ventricular geometry based on magnetic resonance and diffusion tensor magnetic resonance imaging of the heart. The electromechanical model couples detailed repres...
Generalized dynamic motion of balls and cage in a ball bearing are simulated by solving the differential equations of motion under prescribed operating conditions and bearing geometry. The general cage motion is parametrically evaluated as a function of clearances both in the ball pockets and at the guide lands. The design significance of the modeling approach is demonstrated by the prediction of critical clearances which trigger certain instabilities in the cage motion. In more practical terms, the correlation between cage clearances and instability defines a wear life for the bearing under the prescribed operating conditions. 10 refs.
The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. One of the most critical diagnostic devices is the bunch length monitor (BLM), which is to be installed right after each compressor utilizing coherent radiation from the last bending magnet. We describe the components and the optical layout of such a BLM. Based on the setup geometry, we discuss some issues about the coherent radiation signal.
We discuss various superstring effective actions and, in particular, their common sector which leads to the so-called pre-big-bang cosmology (cosmology in a weak coupling limit of heterotic superstring theory). Using the conformal relationship between these two theories we present Kasner asymptotic solutions of Bianchi type IX geometries within these theories and make predictions about possible emergence of chaos. Finally, we present a possible method of generating Horava-Witten cosmological solutions out of the well-known general relativistic or pre-big-bang solutions.
We discuss various superstring effective actions and, in particular, their common sector which leads to the so-called pre-big-bang cosmology (cosmology in a weak coupling limit of heterotic superstring theory. Using the conformal relationship between these two theories we present Kasner asymptotic solutions of Bianchi type IX geometries within these theories and make predictions about possible emergence of chaos. Finally, we present a possible method of generating Horava-Witten cosmological solutions out of the well-known general relativistic or pre-big-bang solutions.
This paper describes the results obtained from two large experimental facilities built at Sandia National Laboratories in Albuquerque, NM. FLAME (Flame Acceleration Measurements and Experiments) is a large horizontal rectangular channel designed to study flame acceleration, transition to detonation, simulation of combustion in containment geometries, component heating, and other problems in hydrogen combustion relevant to reactor safety. The Heated Detonation Tube has been designed to study detonations in hydrogen-air-steam mixtures. Both facilities have been in operation for just over a year. 12 figures.
This paper describes the results obtained from two large experimental facilities built at Sandia National Laboratories in Albuquerque, NM. FLAME (Flame Acceleration Measurements and Experiments) is a large horizontal rectangular channel designed to study flame acceleration, transition to detonation, simulation of combustion in containment geometries, component heating, and other problems in hydrogen combustion relevant to reactor safety. The Heated Detonation Tube has been designed to study detonations in hydrogen-air-steam mixtures. Both facilities have been in operation for just over a year. 12 figures.
The ability to control the flow of water around the body dictates the performance of marine mammals in the aquatic environment. Morphological specializations of marine mammals afford mechanisms for passive flow control. Aside from the design of the body, which minimizes drag, the morphology of the appendages provides hydrodynamic advantages with respect to drag, lift, thrust, and stall. The flukes of cetaceans and sirenians and flippers of pinnipeds possess geometries with flexibility, which enhance thrust production for high efficiency swimming. The pectoral flippers provide hydrodynamic lift for maneuvering. The design of the flippers is constrained by performance associated with stall. Delay of stall can be accomplished passively by modification of the flipper leading edge. Such a desig...
The refractory nature and high ductility of body centered cubic (bcc) phase tantalum makes it a suitable material for corrosion- and wear-resistant coatings on surfaces that are subjected to high stresses and harsh chemical and erosive environments. Sputter deposition can produce thick tantalum films but is prone to forming the brittle tetragonal beta phase of this material. Efforts aimed at forming thick bcc phase tantalum coatings in both flat plate and cylindrical geometries by high-rate triode sputtering methods are discussed. In addition to substrate temperature, the bcc-to-beta phase ratio in sputtered tantalum coatings is shown to be sensitive to other substrate surface effects.
The design of High-Voltage, Direct-Current transmission cables insulated with oil-impregnated cellulose paper is constrained by the maximum temperature and the maximum steady-state and transient stresses (voltage gradients) that the cable insulation can reliably withstand over the desired operating lifetime. Because the electrical stresses in the insulation are related in a very complex fashion to temperature, applied voltage and cable geometry, iterative techniques are required to compute the values of these stresses. Digital computers are ideally suited for these iterative techniques. This paper presents the principal equations and logic needed to develop suitable computer programs.
Role of ballooning effect in toroidal plasmas on the transient transport problems is investigated. Due to the mode localization along the magnetic field line, a meso scale appears in a radial correlation length of fluctuating fields. This scale length introduces the interference of the gradient and flux in different radial locations. For the fluctuation which gives the gyro-Bohm-like diffusion in a stationary state, this long radial correlation of the fluctuating field causes a fast propagation of response against a rapid transient perturbation. Upper bound of transient thermal diffusivity is derived. (author)
The paper reports extensive analyses of the fractal geometry of cellular dislocation structures observed in Cu deformed in multiple-slip orientation. Several methods presented for the determination of fractal dimensions are shown to give consistent results. Criteria are formulated which allow the distinguishing of fractal from non-fractal patterns, and implications of fractal dislocation patterning for quantitative metallography are discussed in detail. For an interpretation of the findings a theoretical model is outlined according to which dislocation cell formation is associated to a noise-induced structural transition far from equilibrium. This allows relating the observed fractal dimensions to the stochastic properties of deformation by collective dislocation glide.
The method of an effective potential is used to investigate the possible types of evolution of vacuum shells in the Friedmann-Schwarzschild world. Such shells are assumed to emerge during phase transitions in the early Universe. The possible global geometries are constructed for the Friedmann-Schwarzschild worlds. Approximate solutions to the equation of motion of a vacuum shell have been found. The conditions under which the end result of the evolution of the vacuum shells under consideration is the formation of black holes and wormholes with baby universes inside have been found. The interior of this world can be a closed, flat, or open Friedmann universe.
This paper will track the design and results of an injection molding tool developed to manufacture microfluidic chips. The mold design and injection molding process was complicated by the presence of integrated capillary fluidic interconnects. We determined that design of the runner and gate system responsible for delivering molten plastic to the cavity had a significant impact on the quality of parts produced by the mold and the size of the process window. Numerical results confirm our findings that reducing gate lengths and increasing part thickness dramatically improved the filling profile and lowered injection pressures by 37%. Finally, the influence of gate location on part shrinkage is analyzed and discussed.
The K sub(#alpha#)/K sub(#beta#) intensity ratio of Mn KX-rays scattered by metallic samples changed remarkably with the geometry between the sample and the "5"5Fe source-Si(Li) detector system. On the contrary, this intensity ratio changed little in the cases of non-metallic scatterer samples such as lucite or mylar. This difference is interpreted as due to the occurrence of strong or weak interference in the coherent scattering photons. (author).
The problem of denting in steam generators leads to change in the conception of the tube support plates. A new material is now used for this component, a 13% Cr steel, which composition has been adjusted for weldability and mechanical resistance criteria. The geometry of trefoil support plate (TSP) has also been improved, using a broached TSP (quadrifoiled holes) instead of a drilled TSP. Tests have been performed on 13% Cr and C-steel broached TSP, and drilled TSP, to confirm the better resistance to denting of this new configuration.
Differentiating characteristics of magnetic confinement systems having externally generated magnetic fields that are open'' are listed and discussed in the light of their several potential advantages for fusion power systems. It is pointed out that at this stage of fusion research high-Q'' (as deduced from long energy confinement times) is not necessarily the most relevant criterion by which to judge the potential of alternate fusion approaches for the economic generation of fusion power. An example is given of a hypothetical open-geometry fusion power system where low-Q operation is essential to meeting one of its main objectives (low neutron power flux).
Purpose/Objective: With the advent of computed tomography and magnetic resonance imaging, the three dimensional representation of the patient anatomy has become an invaluable resource for better diagnosis and delineation of the target volume and sensitive structures in radiation therapy. Although the therapeutic linear accelerator industry has made available highly sophisticated equipment, the aggressiveness in dose prescription and delivery has to be complimented by accurate dose computation methods. We have adopted a convolution/superposition algorithm for the calculation of absolute dose that fully accounts for the external shape and internal structure of the patient for photon treatment radiotherapy. In this paper, we will discuss the principles of the convolution algorithm and we will show how the computed dose compares to clinically relevant treatment techniques. Materials and Methods: A computer controlled data acquisition system and a water tank where used to measure depth ...
Formulae are derived for estimation of the effect of gamma beam divergence on the value of systematic and statistical components of the errors of density measurement in production of structural materials and products also in the process of exploitation of building structures and constructions. Engineering technique for choice of the distance between radiation source and object under test is developed for absorption radioisotope densimeter operating by the scheme of geometry of divergent beam with amplitude compensation of backscattered radiation effect. The assessment of radioisotope densimeter efficiency providing the error of density measurement prescribed at design stage
Burnout data with low pressure Freon-113 for even- and odd- numbered peripheral rod clusters with relatively large spacings were used to derive equations in terms of dimensionless parameters suggested by Barnett. The equations which are for three different flow regimes for each rod geometry (even or odd) were found to predict burnout data with maximum RMS deviation being 3.8%. (author). 11 figs., 3 tabs., 15 refs.
Bone integrity and mineral status were studied with a noninvasive method in uremic patients with severe secondary hyperparathyroidism undergoing maintenance hemodialysis. [Italian] Gli autori propongono un metodo non invasivo per studiare la densita' minerale e le caratteristiche geometriche e biomeccaniche dell'osso nei pazienti uremici affetti da iperparatiroidismo secondario grave.
In this paper we report on multi-physics, multi-billion macroparticle simulation of beam transport in a free electron laser (FEL) linac for future light source applications. The simulation includes a self-consistent calculation of 3D space-charge effects, short-range geometry wakefields, longitudinal coherent synchrotron radiation (CSR) wakefields, and detailed modeling of RF acceleration and focusing. We discuss the need for and the challenges associated with such large-scale simulation. Applications to the study of the microbunching instability in an FEL linac are also presented.
Abstract in english In the last decade it has been experimentally found a periodic domain pattern arising in smectic C* liquid crystals in surface stabilized bookshelf geometry. Such a periodic texture appears after switching-off an external electric field, even in strong anchoring conditions. It has a static character and can be bidimensional, being dependent on both directions normal to the smectic planes and normal to the cell plates. In the present work an explanation to this phenomenon (more) is proposed. According to our model in the antiferroelectric phase the biperiodic texture is a threshold phenomenon, appearing for values of the spontaneous polarization greater than a critical value, whereas in the ferroelectric phase this type of bidimensional instability is hindered.
The Tomographic Gamma Scanning (TGS) technique is a relatively new method in the field of non-destructive assay (NDA) of radioactive waste. The TGS technique combines High Resolution Gamma Spectrometry (HRGS) with Three-Dimensional (3-D) low spatial resolution transmission and emission image reconstruction techniques to achieve assay goals. When compared to the traditional methods such as Segmented Gamma Scanning (SGS), the TGS technique can yield better accuracies for cases where the radionuclide is distributed non-uniformly in a heterogeneous matrix. The TGS technique is ideally suited for low-to-moderate density waste matrices, say 1.0 g cm{sup -3} or below for 55 US gal. drums, although it can be extended to higher densities by using alternative approaches to the design or analyses. Recently Canberra Industries designed, built and characterized four such TGS systems for nuclear power plant applications. Many of the design features and the end application itself set these TGS ...
The Tomographic Gamma Scanning (TGS) technique is a relatively new method in the field of non-destructive assay (NDA) of radioactive waste. The TGS technique combines High Resolution Gamma Spectrometry (HRGS) with Three-Dimensional (3-D) low spatial resolution transmission and emission image reconstruction techniques to achieve assay goals. When compared to the traditional methods such as Segmented Gamma Scanning (SGS), the TGS technique can yield better accuracies for cases where the radionuclide is distributed non-uniformly in a heterogeneous matrix. The TGS technique is ideally suited for low-to-moderate density waste matrices, say 1.0 g cm"-"3 or below for 55 US gal. drums, although it can be extended to higher densities by using alternative approaches to the design or analyses. Recently Canberra Industries designed, built and characterized four such TGS systems for nuclear power plant applications. Many of the design features and the end application itself set these TGS systems ...
The adsorption of benzyl alcohol and 1-phenylethanol on graphitized thermal carbon black at 300 K is investigated. Thermodynamic characteristics of the adsorption of conformers stable in the gas phase and in the adsorbed state are determined by a molecular statistics method. The geometry of the molecules is optimized using the MP2 and B3LYP methods with a 6-311++G(d,p) basis set. Using the PBE0/6-31G(d) method, it is established that, in the adsorption of benzyl alcohol, two types of interactions, CH?O and OH??GTCB, occur. It is shown that, in 1-phenylethanol, intramolecular interactions are maintained.
Computational fluid dynamics(CFD) code FLUENT was used to simulate the thermal hydraulic processes occurring in conceptual design of the accelerator-driven subcritical reactor(ADSR) liquid lead target. The purpose of the analysis is to investigate the thermal hydraulic characteristics of liquid lead as ADSR target material with various target geometries and injection locations of proton beam. In the calculation analysis, the local temperature of the liquid lead target rises to the boiling temperature very rapidly. When the proton beam is injected from the bottom of the target system, the duration time to reach the boiling temperature is longer and the temperature distribution is flatter than other cases.
The single specimen unloading compliance technique has become the preferred method for evaluating J-integrals. It involves data acquisition and analysis using a computer. This paper describes in detail the development of a simple experimental system and related software that can be used in a laboratory equipped with a microcomputer and with access to a minicomputer. The effects of loading rate, test temperature, specimen geometry and material composition can be readily evaluated using this system. The results on a pressure vessel steel and an #alpha#-#beta# titanium alloy are discussed in Part II. (author).
Electrostatic plasma simulation code for 2D rectangular geometry is presented. Main distinguishing feature of the code is its orientation on the beam-plasma interaction. The code and its graphical interface were developed using MATLAB programming language. Simulation results of inhomogeneous plasma interaction with modulated electron beams of different width are compared. In case of wide beam the front of Langmuir waves generated in point of local plasma resonance is planar and in case of thin beam (or ribbon beam) the front has approximately half-circular form.
Precise measurements of alpha particle counting efficiencies have been made using isotropic, infinitely thin alpha emitting sources placed in direct contact with a thin, end-window, gas flow proportional detector. Except for alpha particle absorption in the window material, this geometry approaches 2#pi#, such that the only other variation in the response of the counter is from the random decay of the source. The data are fitted to the expected linear function of count rate versus window thickness and the resulting fitting parameters are used to calculate the counting efficiencies for a given thickness of window material. Counting efficiencies for 5.31, 6.06, and 8,78 MeV alpha particles have been determined from sources of "2"1"0Po and the progeny of "2"1"2Pb. For the particular counter used, the counting efficiencies in counts per alpha and their respective relative standard deviations were 0.401 #+-# 0.12%, 0.418 #+-# 0.41%, and 0.455 #+-# 0.10%. The isotropic, ...
This report is composed of the following two parts and appendix. (I) Improvement of the Method for Evaluating Reactivity Based on Monte Carlo Perturbation Theory: Theoretical formulation in Monte Carlo perturbation method had been checked, and then introduced into a calculation code. There are some cases that the results of the change of eigenvalues becomes positive or negative by changing the estimator, and there is no reasonable difference in the results between the conventional method, which does not consider the change of neutron source distribution caused by a perturbation, and the new method, which consider that change. Thus it is still necessary to check the Monte Carlo perturbation code. (II) Improvement of Nodal Transport Method for 3-D Hexagonal Geometry: We can accurately evaluate hexagonal geometry FBR core by nodal transport calculation code for hexagonal-Z geometry named `NSHEX`. However it is also found that ...
A general space- and energy-dependent formalism is developed in order to analyze zero-power neutron noise experiments in fast reactor systems. A generalized dispersion equation is combined with theoretical expressions for the experimentally measured power spectral density and variance-to-mean ratio which makes it possible to express these quantities in terms of a double moment of the Laplace and Fourier transformed Green's function of a slowing-down operator rather than those of the full Boltzmann operator. Several spatial approximations are analyzed in the context of the general formalism. In each case, the power spectral density and variance-to-mean ratio are written in terms of an appropriate fast reactor dispersion law for the medium which can be calculated from the solution to a simple slowing-down equation. The resultant expression for the power spectral density are analyzed for various combinations of neutron migration descriptions, slowing-down kernels, fission ...
A massively-parallel ab initio computer code, which uses Gaussian bases, pseudopotentials, and the local density approximation, permits the study of transition-metal systems with literally hundreds of atoms. We present total energies and relaxed geometries for Ru, Pd, and Ag clusters with N = 55, 135, and 140 atoms; we also used the DMOL code to study 13-atom Pd and Cu clusters, with and without hydrogen. The N = 55 and 135 clusters were chosen because of simultaneous cubo-octahedral (fcc) and icosahedral (icos) sub-shell closings, and we find icos geometries are preferred. Remarkably large compressions of the central atoms are observed for the icos structures (up to 6% compared with bulk interatomic spacings), while small core compressions ({approx} 1 %) are found for the fcc geometry. In contrast, large surface compressive relaxations are found for the fcc clusters ({approx} 2-3% in average nearest neighbor spacing), ...
A conventional PET scanner has a 15-25 cm axial field-of-view (FOV) and images a whole body using about six bed positions. An OpenPET geometry can extend the axial FOV with a limited number of detectors. The entire whole-body PET scanner must be able to process a large amount of data effectively. In this work, we study feasibility of the fully 3D entire whole-body PET scanner using the GATE simulation. The OpenPET has 12 block detector rings with the ring diameter of 840 mm and each block detector ring consists of 48 depth-of-interaction (DOI) detectors. The OpenPET has the axial length of 895.95 mm with five parts of 58.95 mm open gaps. The OpenPET has higher single data loss than a conventional PET scanner at grouping circuits. NECR of the OpenPET decreases by single data loss. But single data loss is mitigated by separating the axially arranged detector into two parts. Also, multiple coincidences are found to be important for the entire whole-body PET scanner. ...
The linear/supralinear behaviour of the TL dose response in LiF:Mg,Ti (TLD-100) and its dependence on ionisation density is a fairly unique phenomenon which cannot be explained by conventional atomic 'conduction band/valence band' kinetic models. The Track Interaction Model (TIM) provides the microscopic framework which, when coupled with other appropriate physical mechanisms (spatial localisation of traps and recombination centres, competing centres, variations in the capture cross sections with temperature, etc.) can be used to describe all the dominant features of the TL supralinearity of LiF:Mg,Ti and similar TL systems. The unique feature of the TIM applied to alpha particles is that it is an integral approach with only one free parameter, the average charge carrier migration distance in the luminescence recombination stage. Although the TIM provides a comprehensive description of the mechanisms underlying supralinearity in TLD-100, definitive unambiguous proof ...
The operation and safety of both fossil-fuel and nuclear power stations depend on adequate cooling of the thermal source involved. This is usually accomplished using liquid coolants that are forced through the high temperature regions by a pumping system; this fluid then transports the thermal energy to another section of the power station. However, fluids that undergo boiling during this process create vapor that can be detrimental, and influence safe operation of other system components. The behavior of this vapor, or void, as it is generated and transported through the system is critical in predicting the operational and safety performance. This study uses two advanced penetrating radiation techniques, Real Time Neutron Radiography (RTNR), and High Speed X-Ray Tomography (HS-XCT), to examine void generation and transport behavior in a flow boiling system. The geometries studied were tube side flow boiling in a cylindrical configuration, and a similar flow ...
The aim of the present study was to describe the distribution and remobilization of plutonium (Pu) in the sediments off the Rhone river mouth. Most of the {sup 238}Pu and {sup 239,240}Pu isotopes introduced into the Rhone River were discharged by the liquid effluents released from the Marcoule reprocessing plant, located 120 km upstream the river mouth. Due to its high affinity for particles and its long half life, {sup 238}Pu is a promising tracer to follow the dispersion of particulate matter from the Rhone River to the Mediterranean Sea. During the 3 REMORA cruises, sediment samples were specifically collected in the Rhone pro-delta area and more offshore on the whole continental shelf of the Gulf of Lions. The measurements of alpha emitters gave a first detailed spatial distribution of Pu isotope concentrations in surface sediments off the Rhone mouth. Using {sup 137}Cs concentrations and their correlations with Pu isotopes, we were able to give a first estimate of Pu inventories ...
A.C.R.O. (Association pour le Controle de la Radioactivite dans l'Ouest) is a French non governmental organisation that operates a laboratory for radioactivity analysis. It was created in 1986 as a response to people demands for information and reliable, independent testing. The organisation mainly carries out missions of information and training for its correspondents and more generally for a wide audience, particularly for people who worry about problems of environment, health, management of radioactive waste and emissions. Thanks to its structure, it enables citizens to involve themselves together with scientists so as to gain access to information that was hither to reserved to specialists. The organisation can vouchsafe its independence from the diversity of its members and volunteers, as well as from the diversity of its money resources. Besides its headquarters situated on the city of Caen area (Normandy), three branches situated in North Normandy, ...
Normally, the alloy NiMo28 is used in the solution annealed and quenched condition in which it has a face centred cubic matrix structure. The matrix of the material is supersaturated with molybdenum and, at temperatures above 800 C, has a tendency to form intermetallic precipitates such as the Ni{sub 4}Mo-ordered phase leading to the embrittlement of the NiMo28-ordered phase leading to the embrittlement of the NiMo28 alloy during hot working. For this reason, the aim of these investigations was to optimise the alloy by reducing its tendency to embrittle. The TEM-analyses carried out served to investigate the precipitation of the material as a function of its iron content after ageing at 700 C. The change in hardness and in the lattice constants of the NiMo28-specimens with iron content were also determined. To improve the hot working properties of this material it is recommended that the iron content be kept to about 3.2 mass % in order to reduce the tendency of the alloy to ...
DMT has developed what is called the stepped reforming process. This is an allothermal gasification process which uses hydrogen for a gasification medium. First the biomass is pyrolised by means of a heat transfer material. The escaping gaseous and condensable constituents are hydrogenated, heated in a reforming stage and are made to react to a hydrogen-rich product gas by means of homogeneous gasification. The heat required for this is provided by burning the pyrolysis coke. This makes it possible to dispense with process stages that would involve gasification of solid material and hence require higher pressure levels. The present process also works at ambient pressure. Moreover, stepped reforming promises a number of additional advantages: low-tar product gas containing 60% hydrogen, high cold gas efficiency, no wastewater arisings, robust operating behaviour. This paper outlines the basic ideas that led to the development of stepped reforming process and describes its diverse ...
In the year 1996 the spheres of competence of several DLR-Institutes working in the areas of fluid dynamics, reaction kinetics, combustion, numerical methods and laser measuring techniques have been brought together while contributing to the internal DLR project 'combustion chamber modelling (BKM)', in order to proceed with the computational simulation of combustion processes in combustion chambers of gas turbines. The main issue was the development of a research code for numerical simulation of fluid flow in real combustion chambers. Here the development of computational models of physical and chemical processes was emphasized, among other processes the formation of soot was treated. Moreover, a worldwide outstanding database of measured data for the purpose of code validation has been created within the framework of the BKM project using the laboratory facilities of the DLR, which are in Germany unique for the experimental investigation of the various processes in ...
During their life, intervertebral discs undergo degenerative changes which need not necessarily become lesions. Conventional X-rays do not provide information on the condition of the intervertebral discs, so MRT or CT are recommended as primary techniques as they are non-invasive. Invasive methods like myelography and especially discography should not be used unless a case is highly problematic. In infants with pains in the back, MRT should be carried out as early as possible as there is nearly always an organic cause. (orig.) [German] Die Bandscheibe ist im Laufe des Lebens degenerativen Veraenderungen unterworfen, die klinisch zu Beschwerden fuehren koennen, aber nicht fuehren muessen. Konventionlle Roentgenaufnahmen lassen zwar die Hoehenminderung des Bandscheibenfachs und begleitende knoecherne Veraenderungen erkennen, nicht aber den Zustand der Bandscheibe selbst. Die Beurteilung der Bandscheibe und des Knochens ...
Preserving customers` investments in capital goods is one of the strategic market services offered by ABB, and to this end the company has developed project-specific retrofit concepts especially for older power generation plant. A prime example of such a modernization is the Umm Al Nar East (UANE) combined cycle power station in Abu Dhabi, UAE. UANE has two gas turbines of type GT13D, which together generate 140 MW of electrical energy, and heat-recovery boilers which supply steam to a seawater desalination plant with a capacity of 80 million liters of drinking water per day. After almost 20 years in operation, UANE is being modernized. To address the owner`s concerns and minimize plant downtime, ABB has introduced Service, Operation and Rehabilitation (SOR) Key Account Management for Abu Dhabi. In the first phase of the modernization project, the static starting equipment was upgraded and the mechanical turbine governor replaced by the EGATROL electro-hydraulic control system. Also, ...
In comparison to deterministic criteria, probabilistic reliability indices like interruption frequency and unavailability give a more differentiated insight into reliability in an electrical energy network. One possibility for network planning based on these indices is the definition of limits for customer nodes, another is the monetarisation of reliability in terms of interruption costs. Because of numerous disadvantages, interruption cost methods could not up to now win broad recognition in network planning in Western Europe. A more recent method for the monetarisation of reliability circumventing most of these disadvantages is the insurance system. In this system the customer selects a tariff class in an insurance system, and the utility reimburses its customers in the case of an interruption. In its first section, the paper describes a method for the flexible and realistic optimisation of MV networks. This method based on Genetic optimisation is able to integrate probabilistic ...
Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. Especially for follow-up examinations in ...
The influences of temperature and duration of tempering on hardness and microstructure were investigated at high-temperature martensitic and low-carbon steels with 9% chrome and the further alloying elements molybdenium, vanadium, niobium and partially tungsten. After austenitizing and subsequent air cooling the steels were tempered at temperatures below, at and above Ac{sub 1b} for different times and finally a hardness test was performed. Making use of the temperature dependence of the hardness tempering diagrams were constructed and the Hollomon-Jaffe-Parameter on the three steels was determined within its application limits. Micrographs of the structure shows the formation of the carbides and the martensite. At tempering temperatures below Ac{sub 1b} a decrease of hardness occurs, above Ac{sub 1b}, a hardness rise due to the partial austenitizing was obtained. While hardening below Ac{sub 1b}, the tempering quality increases from P 91, NF 616 to E 911. (orig.) [Deutsch] An ...
FLUTAN is a highly vectorized computer code for 3D fluiddynamic and thermal-hydraulic analyses in Cartesian or cylinder coordinates. It is related to the family of COMMIX codes originally developed at Argonne National Laboratory, USA, and particularly to COMMIX-1A and COMMIX-1B, which were made available to FZK in the frame of cooperation contracts within the fast reactor safety field. FLUTAN 2.0 is an improved version of the FLUTAN code released in 1992. It offers some additional innovations, e.g. the QUICK-LECUSSO-FRAM techniques for reducing numerical diffusion in the k-{epsilon} turbulence model equations; a higher sophisticated wall model for specifying a mass flow outside the surface walls together with its flow path and its associated inlet and outlet flow temperatures; and a revised and upgraded pressure boundary condition to fully include the outlet cells in the solution process of the conservation equations. Last but not least, a so-called visualization option based on VISART ...
Already in 1998, the city of Hanover, the Stadtwerke Hannover and six further cities of the region initiated the funding programme 'Hannover proKlim' for promoting energy-relevant modernization measures in domestic buildings. One year later, the social marketing campaign 'Haus-Partner Hannover / Der (H)Eissbaer'' was started, which addresses building owners in Hanover with the intention to induce them to action. The 'Energiepass Hannover' is another important instrument of the campaign. This report takes stock of the results achieved so far. [German] Beim Klimaschutz im Gebaeudebestand lassen sich in Hannover drei Ansaetze hervorheben, die parallel zueinander entwickelt wurden und die in besonderer Weise dazu beitragen, die CO{sub 2}-Emissionen im Gebaeudebestand zu reduzieren: Bereits 1998 hat die Landeshauptstadt Hannover gemeinsam mit den Stadtwerken Hannover und sechs weiteren Staedten der Region den Klimaschutz-Fonds ...
We performed a comparative study of digitally and conventionally acquired images in gastrointestinal examinations. Radiation dose and spatial resolution were determined in a water phantom. In 676 examinations with either conventional or digital imaging (system: Diagnost 76, DSI) the number of images and the duration of the fluoroscopy time were compared. 101 examinations with digital as well as conventional documentation were evaluated by using 5 criteria describing the diagnostic performance. The entrance dose of the DSI is 12% to 36% of the film/screen system and the spatial resolution of the DSI may be better than that of a film/screen system with a speed of 200. The fluoroscopy time shows no significant difference between DSI and the film/screen technique. In 2 of 4 examination modes significantly more images were produced by the DSI. With exception of the criterion of edge sharpness, DSI yields a significantly inferior assessment compared with the film/screen technique. (orig./MG) ...
Purpose: Budd-Chiari syndrome is a fairly uncommon disease in Europe. This often leads to its late diagnosis. The syndrome is characterised by portal hypertension and splanchnic congestion due to obstruction of hepatic venous outflow. This paper describes the treatment of three patients with Budd-Chiari syndrome by interventional therapeutic techniques and discusses alternative treatment modalities. Patients and Methods: The first patient presented with veno-occlusive disease and was treated by the placement of a transjugular intrahepatic portosystemic stentshunt. The second patient showed an occlusion of the major hepatic veins. After percutaneous recanalisation, a stent was placed in the right hepatic vein which remained patent. The third patient had a membranous obstruction of the right hepatic vein which was treated by percutaneous balloon dilatation. Results: In all patients the clinical symptoms resolved completely after treatment and no complications were encountered. ...
The influence of a decarburisation process during austenitising of the through-hardenable rolling bearing steel 100Cr6 (SAE 52100) on the rim zone properties of the martensitic through-hardened material was investigated by means of material analysis and diffusion calculations. For this purpose, two specimens were prepared under defined heat treatment conditions, and the near-surface carbon distribution was determined micro-chemically by using secondary ion mass spectrometry (SIMS). In part 1 of the present work, these concentration profiles are compared with the depth variation of the micro-hardness and with the distance curves of the residual stresses and the line broadening ({l_brace}211{r_brace} {alpha}'-Fe diffraction line) both measured by X-ray diffraction (XRD). In addition, microstructure investigations were performed. In part 2, a refined kinetics model of a diffusion-controlled reaction based on the finite element method (FEM) will be applied to the decarburisation ...
The German National Group of the International Nuclear Law Association, AIDN/INLA, held its 10{sup th} regional conference in Celle on September 2 and 3, 2004. The event was attended by approx. 120 participants from twenty countries discussing 'the Internationalization of Nuclear Law'. Four sessions were devoted to in-depth studies of these topics: - Legal problems associated with the management of radioactive waste. - Regional nuclear safety vs. global nuclear safety. Do the Europeans need a supplementary EU regime of nuclear safety? - Liability and insurance in cases of nuclear damage. - Topical issues of German nuclear law. (orig.)
Different cooling speeds after previous solution annealing at 1130deg C for 0.5 hour were simulated in laboratory experiments. The following conditions were examined: (1) Direct water quenching, (2) cooling in air for 0.5 min to 950deg C/water quenching, (3) cooling in air for 1.5 min to 750deg C/water quenching, (4) cooling in furnace for 5 min to 750deg C/water quenching. The results of the investigations have shown that a variation of the cooling conditions causes considerable changes in the creep behaviour. (orig.).
Calcium sulfate dihydrate which is co-produced in the scrubbing of waste gases from bituminous coal power plants is employed in the underground road securing after recrystallization. Beta-sulfate semi hydrate is obtained from the dihydrate by recrystallisation and it is used as such or as a stiff mixture with additives as a stowing material. Particularly fly ash from coal combustion units, washery refuses and development rocks from coal mining or slags from the metallurgical industry can be used as additives. The compressive and the bending tensile strength of the stowing material can be adjusted by the water content in case beta sulfate semihydrate is used as such.
The author investigates whether the international law regime so far has developed any legal principles dealing with the problem of the dumping of radioactive waste in the sub-seabed, and whether any of such provisions available adequately tackle the problem in the light of the gravity of danger emanating from radioactive waste. The study covers over 30 different texts of international treaties and protocols. Points of main interest are the London Dumping Convention and the Montego Bay Convention on the Law of the Sea. The author concludes that the disposal of radioactive waste into the seabed belongs to the permissible, although not specially allowed activities within the framework of the freedom of the high seas, and therefore urgently calls for establishing an international regulatory system pertaining to the planning and accomplishment of such activities. An outline legal concept of a regulatory system is explained. (orig./HSCH).
Because power requirements in induction heating applications are largely dependent on the physical properties of the product to be heated, inducting, heating is mainly used in steelwork applications, for the manufacture of finished or semi-finished parts. Applications here cover five main types of steelworks operation: smelting, heating prior to forming, heat treatment, surface treatment, and assembly process. At the same time, technological progress has opened up innovative applications in sectors such as chemical and agro-food industries. Other emerging applications for induction include direct forming of liquid metal, wholly or partially replacing mechanical transformations on solid metal. Techniques include electromagnetic forming, continuous cold-crucible casting, electromagnetic mixing, flow control by continuous magnetic field, and production of intense sliding fields (pumps, flow regulation). (author)
The dogmatic and constitutional basis as well as points of definition concerning the Technical Code Clean Air (TA Luft) are explained at first, followed by an assessment of the air pollution concentrations within the overall complex of the air pollution abatement measures, and an analyses of air pollution concentrations as a concretization of the state-of-the-art. In connection with the differentiation of the various applicability levels of TA Luft, the inhouse validy for authorities, the importance for law courts and, finally, the external binding effect for plant operators and possible third parties are discussed. At the center of attention are questions concerning validity claims and validity possibilities. (HSCH).
Over the decades, basic research in life sciences has profited greatly from the study of the small unicellular fungal species Saccharomyces cerevisiae. This yeast turned out to be key for the identification and understanding of molecular mechanisms that underlay the basic functions of all eukaryotic cells. These include, but are not limited to, the regulatory mechanisms behind cellular reproduction (cell cycle control), cellular morphogenesis (cell polarity, cytoskeleton and membrane trafficking) and the management of cellular information (chromosome biology, transcription and translation). Rapid access to genomic information of many yeast species, combined with bioinformatics analyses, provide information on the evolutionary history of yeasts and the molecular ancestry of their constituen...
Technical education in the preparatory classes for the technology-based 'baccalaureat' prioritize experimental teaching activities. With the option 'Genie Electrotechnique', the subjects always deal with systems or processes connected with the use of electrical energy. Among the different topics, a lighting system brings to many prospects which cover various points of the teaching syllabus. After defining and studying the technical object, it is necessary to consider the educational adaptation by a model whose reduction scale must take into account the dimensions, cost and security constraints. Thanks a concrete example this paper describes a tool that brings to test and confirm the small scale model. Some teaching activities can be then considered but never losing touch with the actual application. (author)
Zusammenfassung Eine genauere Untersuchung der bekannten Modelle isotropen Materialverhaltens (z.B. von Mises, Tresca, Mohr-Coulomb, Drucker-Prager usw.) zeigt, dass sie selten mit Versuchsergebnissen ?bereinstimmen. Modelle mit inkompressiblen Eigenschaften sch?tzen oft das Materialverhalten bei mehraxialen Zugbelastungen falsch ein. Beim Flie?en unter Druck liefern die Modelle mit kompressiblen Eigenschaften unzul?ssige Werte der Querkontraktionszahl. Erfahrungen zeigen, dass es schwierig ist, mehrdimensionales Materialverhalten bei h?ufig fehlenden Informationen werkstoffgerecht abzubilden. Viele Modelle liefern akzeptable Ergebnisse nur f?r bestimmte Bereiche des Spannungsraumes. Diese Beobachtung hat auf die Idee gef?hrt, ,,bew?hrte?? Modelle miteinander zu verbinden. In diesem Artike...
The program introduced here for determining and describing the multi-axial creep of pipes is based, on the one hand, on the results of the nuclear process heat prototype plant material program and, on the other hand, on the possible load conditions which arise for evaluating accidents or extreme working situations. The basis of a theoretical description of multi-axial creep is the invariant theory in which both the von Mises configuration change hypothesis and the Norton creep law are included. Combined tension and torsion are also considered in detail, the superimposition of cyclic stresses in the tensile threshold area is discussed and cases of partial relaxation are explained. Experimental results for the discussed loads are introduced, which have led to satisfactory agreement between theory and experiment. (orig./MM).
With the exception of the 1945 Hiroshima and Nagasaki nuclear weapon explosions and the 1986 Tchernobyl reactor accident, most of the radiation accidents concerns the medical and the traditional industrial sectors. The seriousness of the accident is directly function of the absorbed dose. The paper, first, gives the definition of a radiologic accident with its specific criteria and pathological manifestations. Then, some famous historical accidents are reviewed from the discovery of X-rays to recent acute irradiations due to the careless manipulation of radiation sources. From this analysis, three main causes are put forward: the dysfunction of nuclear medicine apparatuses, the victims` lack of training and knowledge of the risks, and the non-identification or the loss of radiation sources. (J.S.). 1 photo.
Zusammenfassung Das Konzept der ?quivalenten Spannung (Vergleichsspannung) wird seit langem angewendet und hat sich bew?hrt. Ein wesentlicher Grund daf?r liegt darin, dass es u.?a. bei der Formulierung ph?nomenologischer Werkstoffmodelle weiterhilft. Von Nachteil ist, dass es weder mit physikalischen Prinzipien in Verbindung steht, noch Informationen ?ber die Mikrostruktur des Werkstoffs enth?lt. Trotzdem wurden zahlreiche Hypothesen zur Formulierung von ?quivalenten Spannungen in der Vergangenheit aufgestellt und in der Praxis mit unterschiedlichem Erfolg angewendet. Als Basis f?r die Systematisierung der zahlreichen Modelle hat Yu die Unified Strength Theory (UST) vorgeschlagen. Diese eignet sich, u.?a. inkompressibles inelastisches Materialverhalten sowie kompressible Werkstoffe mit unt...
The study abstracted aims at analyzing the economic effects of energy policies using simulations. Emphasis is on assessing the effects of decisions in favour of an expanding electric power industry based on nuclear energy and hard coal. The study discusses alternative assumptions concerning the cost involved, pollution abatement measures, shutdown and dismantling costs etc. Input-output analyses make the simulation model a consistent vehicle. Besides, the model in question is characterized by its explaining the investment demand of the different sectors by referring to the continuous annual development of innovative technologies.