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,...
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.
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 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 ...
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 ...
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 ...
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...
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 ...
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.
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?.
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.
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.)
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.)
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.)
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.
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 ...
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 ...
Anatomical specimens and normal persons were studied by gradient echo MR imaging to determine the influence of different echo times (TE) on bone marrow contrast. First of all, six normal persons were studied to determine specific echo times for in-phase and opposed-phase states. Using different sequences bone marrow contrast in isolated femoral bones was determined and compared to results of pathological exams. Red bone marrow had no signal on opposed-phase images; contrast between red and yellow marrow was higher on opposed-phase than on in-phase images. Bone marrow lesions can be expected to be visualised with high signal on opposed-phase images; this technique should be especially suited for MR imaging of bone marrow. (orig.).
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 ...
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 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 ...
MRT is able to demonstrate arteries while MR angiography can quantify blood flow by a non-invasive method. In the present paper blood flow measurements were carried out in four selected cases on the basis of phase mapping. In 3 patients with lesions in the pelvis or thigh, angiography was performed in order to localise the stenosis or occlusion and this was followed by qantitative blood flow measurements. The results showed that angiography may not always provide all necessary information concerning a haemodynamically significant stenosis. The method may also be used for quantifying blood flow in the renal arteries and that it has significant advantages over the colour Doppler method. (orig.).
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.)
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 ...
The electrochemical performances of orthorhombic LiMnO{sub 2} compounds are analyzed in order to find a structural and/or morphological origin to the differences of electrochemical behaviours observed in compounds with different size of crystallites and different amounts of lattice defects. Energy capacity performances of 200 Ah/kg are reached for materials with crystallites of about 10{sup 7} Angstrom{sup 3} and with about 7% of defects, while energy capacities of only 80 Ah/kg are obtained for materials with ten times bigger crystallites. (J.S.) 3 refs.
Two isothermal sections were prepared at 1000 and 1150 C showing the low-Zr phases of the system Fe-Al-Zr. The phase equilibria were determined by means of X-ray powder diffractometry and electron beam microanalysis. For initial characterisation of mechanical properties, hardness values are determined and added to the tabulated data. (orig./MM) [German] Es werden am Fe-Al-Zr-System zwei isotherme Schnitte durch den zirkoniumarmen Teil des Systems bei 1000 und 1150 C erstellt. Die auftretenden Phasengleichgewichte werden mit Hilfe der Roentgenpulverdiffraktometrie und Elektronenstrahlmikroanalyse aufgeklaert. Zusaetzlich werden zur ersten Charakterisierung der mechanischen Eigenschaften Haertewerte bestimmt.
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 ...
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 ...
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. ...
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 ...
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 ...
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 ...
{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. ...
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, ...
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 ...
The spent fuel management concept of direct ultimate disposal is compatible in its fundamental features with the law of the European Community. This applies to a national law prohibiting spent fuel reprocessing and the handling of plutonium in Germany, imposing restrictions on exporting spent fuel assemblies and importing plutonium and reprocessing remnants, and on power plant operators to employ reprocessing services abroad. Also, a nuclear power phase-out decided by the German government would in principle not mean a breach of the EURATOM treaty. (orig./HP) [Deutsch] Als Alternative zur geltenden Rechtslage werden im Deutschen Rundestag Aenderungen vorgeschlagen, die das Entsorgungskonzept der direkten Endlagerung - d.h. ein Verbot der Wiederaufarbeitung von Brennelementen aus deutschen Kernkraftwerken auch im europaeischen Ausland - vorschreiben und einen ``Ausstieg`` aus der Kernenergienutzung anordnen. Vor dem Hintergrund einer Analyse der tatsaechlichen ...
Universal Oil Products, Inc. (UOP) of Des Plaines, Illinois has contracted A.E. Roberts & Associates, Inc. (AERA) of Atlanta, Georgia to prepare a sensitivity analysis for the development of the Fluidized-bed Copper Oxide (FBCO) process. As proposed by AERA in September 1991, development of the FBCO process design for a 500 mega-watt (MW) unit was divided into three tasks: (1) Establishment of a Conceptual Design, (2) Conceptual Design, (3) Cost Analysis Task 1 determined the basis for a conceptual design for the 500 megawatt (MW) FBCO process. It was completed by AERA in September of 1992, and a report was submitted at that time {open_quotes}Establishment of the Design Basis for Application to a 500 MW Coal-fired Facility.{close_quotes} Task 2 gathered all pertinent data available to date and reviewed its applicability to the 500 MW FBCO process. Work on this task was carried out on a joint basis by the AERA team members: Roberts & Schaefers worked on the ...
This paper provides some results of the research works at low pressure components of steam turbines and some construction solutions resulting in a modernisation. The problems of turbine phases for the transonic flow are analysed with respect to reducing profile and margin losses. The origin and flow of wet steam and its influence on corrosion and erosion is investigated. Inlet and outlet casing of the flow channels and transfer diffuser between second last and last phase are mentioned. (orig.) [Deutsch] Im Beitrag werden einige Ergebnisse der Forschung der Teile von ND-Teilen der Dampfturbinen angegeben, und werden irgendeine Konstruktionsloesungen, die fuer ihre Modernisierung guenstig sind, beschrieben. Kurz wird die Problematik der Turbinenstufen fuer die transsonische Stroemung analysiert, mit Hinsicht auf die Erniederung der Profil- und Randverluste. Weiter ist die Aufmerksamkeit der Entstehung und Stroemung des ...
TRITEX was a pumped loop with Pb-15.8Li, fabricated from steel 1.4922. In contact with the molten eutectic were also molybdenum, vanadium and armco-iron. The loop was originally designed to investigate tritium extraction using solid getter metals. Over the years the goal changed to the study of metals, corrosion products and purification of the eutectic mixture. Therefore many modifications were done. The first part of this report describes TRITEX. All parts were enclosed in thermoboxes for a homogeneous temperature. One test section was in an argon glove box and could be opened during operation. Other special equipment`s were: permeation membranes and liquid-metal-covergas-interfaces to study the transport of H{sub 2}, D{sub 2} and {sup 3}H, different purification devices, a quartz observation window to see the liquid metal surface, 4 different kinds of flow measurements, level indicators, freeze valves. The second part describes loop operation. Between 1989 and 1996, the eutectic ...
In the case of a serious accident and as a precautionary measure, several protection actions can be implemented by the prefect during the emergency phase. In France the levels of intervention are given by a ministerial decree of the 13. october 2003, resuming recommendations of the International Atomic Energy Agency. The selected values are: an efficient dose of 10 mSv for the stake under cover and in the listening: the concerned persons have to put under cover in a building, any openings carefully closed and stay in the listening of the orders of the prefect; an efficient dose of 50 mSv for evacuation; an efficient dose to the thyroid of 100 mSv for the taking of stable iodine tablets. In order to help the authorities to choose between the keeping of populations at their place or immediate evacuation the decision criteria are: if the forecasted efficient dose of the first month is under 1 mSv, the populations stay in place; if the forecasted efficient dose is ...
The AVR experimental nuclear reactor was Professor Dr. Rudolf Schulten's brainchild. Visionary ideas led to the success of this technology: - Helium coolant because of the particularly high heat transfer coefficients; - an integrated primary system reactor concept as the basis of all safety considerations in the interest of maximum safety; - uranium-235 and thorium-232 fuel allowing new fuel to be bred; - high temperatures for electricity generation at maximum thermodynamic efficiencies, i.e. optimum fuel utilization; - the possibility to run chemical processes economically at high temperatures by means of nuclear fuels; - the inherent safety of the reactor, for a major accident accompanied by a complete loss of cooling cannot occur for nuclear physics reasons, as was tested twice in the AVR. The AVR attained its first criticality on August 28, 1968. It was operated for more than 20 years, until December 31, 1988, at approximately 67% time utilization, which is an excellent ...
About 25 years after the last edification of a new large high voltage institute at Technical University of Karlsruhe and about 10 years afte the edification of the test lab at Kaiserslautern University, the Brandenburg Technical University of Cottbus had the opportunity to design new high voltage test facilities from the very beginning on and to realize it in a very short time. To review the project from the first ideas followed by the planning and realization phase and the final commissioning of the technical equipment, this book should be a contribution to spred the experiences made among interested people and to demonstrate the actual technical possibilities. To ensure an international exchange of these experiences, all co-authors to the trouble to translate their participation's also to the English language. (orig.) [German] Etwa 25 Jahre nach dem letzten grossen hochspannungstechnischen Institutsneubau in der deutschen Hochschullandschaft an der TH ...
The quantitative measurement of carbon concentration-distance curves serves as fundamental prerequisite for the evaluation of rim zone properties connected with decarburisation processes in material science. This was shown in part 1 of the present work with two samples from through-hardenable rolling bearing steel 100Cr6 (SAE 52100) austenitised in different oxidising atmospheres by position dependent determination of hardness, residual stresses, and X-ray line broadening ({l_brace}211{r_brace} {alpha}'-Fe diffraction line). In practice, it is important to predict carbon concentration-distance curves under prevailing heat treatment conditions or to conclude conversely from profile measurements. Based on a refined kinetics model of a diffusion-controlled process, part 2 therefore presents a simulation tool developed by means of the finite element method (FEM). Apart from the concentration dependence of the diffusion coefficient, it also considers the decarburisation induced ...
By retrofitting the existing steam turbine dual purpose power plant with a gas turbine plant and a secondary waste heat boiler the Technische Werke Ludwigshafen AG have considerably improved the energy generation in energetic, economic and ecological terms. The extension of the existing system to a combined cycle process has lead to this positive effect. The erection of a boiler plant during the first two construction phases has fully met the optimistic expectations. (orig.) [Deutsch] Mit der Nachruestung eines vorhandenen Dampfturbinen-HKW um eine Gasturbinenanlage mit nachgeschaltetem Abhitzekessel haben die Technischen Werke Ludwigshafen AG ihre Energieerzeugung entscheidend in energetischer, oekonomischer und oekologischer Sicht optimiert. Insbesondere die Erweiterung des vorhandenen Systems zu einem GuD-Prozess fuehrt zu dieser positiven Bilanz. Die Errichtung der Kesselanlage in den ersten beiden Bauabschnitten hat die optimistischen ...
The first equipment installed at KfK-HDB was a system with a thin-film evaporator. This was later replaced by two vapor compression evaporating units with forced circulation, for evaporation of liquid LAW, and a steam-heated natural circulation evaporator, for evaporation of liquid MAW. Nuclear activities of the Karlsruhe Nuclear Research Center phasing out, the liquid radwaste quantities to be treated have been shrinking accordingly, so that the current system is planned to be replaced by a smaller system with a thin-film evaporator. (orig./HP) [Deutsch] Im Laufe der Jahre wurde die Anlage mit Duennschichtverdampfer durch zwei Bruedenkompressionsverdampfer mit Zwangsumwaelzung fuer die Eindampfung leicht aktiver waessriger Abfaelle und einem dampfbeheizten Naturumlaufverdampfer fuer die Eindampfung mittelaktiver waessriger Abfaelle ersetzt. Mittlerweile sinkt der Abwasseranfall seit Jahren stetig aufgrund der sinkenden Aktivitaeten des ...
The contribution is concerned from a legal point of view with the systematic recording, classification and assessment of specific problems concerning the post-operational phase of a nuclear power plant. As an introduction, present experience with decommissioning in the Federal Republic of Germany is dealt with. The first part treats the factual side of section 7 III AtG, explains the terms mentioned, the concrete extent of licensing and priority relations. In part 2 the preconditions for licensing pursuant to section 7 III AtG are dealt with, the stipulations of which are made difficult in particular on account of the reference in section 7 III sentence 2 AtG. The third part is concerned with the legal consequence of section III AtG, i.e. the extent of official discretionary powers, whereby aspects of radioactive waste management carry great weight. In part four administrative and procedural particularities in the legal sense relating to licensing according to ...
The aim of this work is to combine the MCFC cathode Li{sub x}Ni{sub 1-x}O properties to those of the protective coatings of LiCoO{sub 2}, Li{sub 2}TiO{sub 3} or of CeO{sub 2}, less soluble in the molten carbonates. In the cases of LiCoO{sub 2}, have been carried out by controlled potential coulometry in aqueous solution, a deposition of Co{sub 3}O{sub 4} on dense Ni. The cobalt oxide reacts rapidly in the Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3} medium at 650 C to give LiCoO{sub 2}, a spinel cubic phase revealed by Raman spectroscopy. (O.M.)
The interfacial area transport equation dynamically models the two-phase flow regime transitions and predicts continuous change of the interfacial area concentration along the flow field. Hence, when employed in the numerical thermal-hydraulic system analysis codes, it eliminates artificial bifurcations stemming from the use of the static flow regime transition criteria. Accounting for the substantial differences in the transport phenomena of various sizes of bubbles, the two-group interfacial area transport equations have been developed. The group 1 equation describes the transport of small-dispersed bubbles that are either distorted or spherical in shapes, and the group 2 equation describes the transport of large cap, slug or churn-turbulent bubbles. The source and sink terms in the right-hand-side of the transport equations have been established by mechanistically modeling the creation and destruction of bubbles due to major bubble interaction mechanisms. In the ...
Customized reference tubes reduced sensitivity discrepancies able to be observed from one probe to the other, due to the gain setting adjustment required for a pre-definite level in amplitude response of the artificial notch. The use of a reference circuit in place of a reference part, makes characterization of the probe matched to its generator more accurate: - the material dependence is cancelled during the compensation process, - the reference signal can be adjusted more accurately in amplitude and phase response, - the manufacturing cost is reduced compared to the one necessary for machining the reference part, - the amplitude and phase response of the reference circuit can be simply modelled by using the transformer relations, such as one can appreciate the variations of the probe definition parameters and its connexion to the generator, and makes them optimal for use. The method proposed by ALSTOM for the characterization of the condenser ...
The ODS superalloys MA 6000 and MA 760 were investigated with regard to their behaviour under non-isothermal fatigue stress. For this purpose, strain-controlled thermomechanical and bithermal experiments with different phase relationships between strain and temperature were carried out on the one hand; on the other hand, the deformation behaviour under thermomechanical stress was modelled on the basis of isothermal cyclic creep data. The fatigue experiments show that a diamond-shaped cycle derived from the stress pattern of a turbine blade is clearly less critical than in-phase and out-of-phase cycles. The life of the diamond-shaped cycle is determined by oxidation-induced crack initiation and propagation and can be predicted easily with a suitable damage model. Important damage parameters required by the model can be obtained by the less complicated bithermal fatigue tests. Modelling of the TMF hystereses suggests that ...
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)
Purpose: To determine the diagnostic value of high resolution MR imaging with a circularly polarised (c.p.) body phased-array coil for the staging of pelvic lymph nodes in cervical carcinoma. Material and methods: 42 patients with histologically proven carcinoma of the cervix were studied on a 1.5 T scanner by using a c.p. body phased-array coil. The imaging protocol included T{sub 2}-weighted turbo-spin-echo (TSE) and T{sub 1}-weighted spin-echo sequences pre and post IV application of Gd-DTPA; slice thickness was 5-7 mm and pixel size 0.53 mm{sup 2}. Lymph nodes with a diameter of {>=}8 mm were considered to have metastatic involvement. MR imaging results were compared with histopathologic findings. Results: MR imaging showed enlarged lymph nodes ({>=} 8 mm) in 16 of 18 patients with histologic proof of lymph node metastases (sensitivity 89%). In 22 of 24 cases MR findings were true negative (specificity 92%). Diagnostic accuracy was ...
Sulfate attack of cement-based materials remains an important problem for the durability assessment of containers and disposal engineering barriers dedicated to the long-term storage of radioactive wastes since underground water which may reach these elements contains small quantities of sulfates (7-31 mmol/1). This work contributes to the study of sulfate-induced damage mechanisms, to their understanding and modelling. The experimental phases of this study aimed at the understanding of the different physico-chemical phenomena involved during an external sulfate attack at following their evolution and their impact on the transport and mechanical properties of the material. Leaching experiments in pure water and in a solution of sodium sulfate (with a sulfate content of 15 mmol/1), have been performed simultaneously on OPC paste (w/c 0,4)in order to allow a comparison of test results. The frequent analysis of the leachant has shown a consumption of sulfate ions by ...
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 ...
The two-phase flows involve interfacial interactions which modify significantly the structure of the mean and fluctuating flow fields. The design of the two-fluid models adapted to industrial flows requires the taking into account of the effect of these interactions in the closure relations adopted. The work developed in this thesis concerns the development of first order two-fluid models deduced by reduction of second order closures. The adopted reasoning, based on the principle of decomposition of the Reynolds stress tensor into two statistically independent contributions turbulent and pseudo-turbulent parts, allows to preserve the physical contents of the second order relations closure. Analysis of the turbulence structure in two basic flows: homogeneous bubbly flows uniform and with a constant shear allows to deduce a formulation of the two-phase turbulent viscosity involving the characteristic scales of bubbly turbulence, as well as an ...
In the present work the effect of different surface conditions on plasma nitriding response of AISI M2 high speed steel was investigated. The plasma nitriding of ground and sandblasted samples and drills was performed at temperatures of 400 C and 500 C for two gas mixtures: 5 vol.% N{sub 2} and 76 vol.% N{sub 2} in hydrogen. Surface layers were characterized before and after plasma nitriding concerning the microstructure, roughness, microhardness, chemical composition, phase composition and residual stress states. Machining tests were carried out with drills during which drilling forces and flank wear have been measured. A significant effect of the surface state prior to nitriding on residual stress states and the properties of the nitrided layer and untreated core has been observed. Thinner nitrided layers on ground and sandblasted samples were attributed to high compressive residual stress states and a stress affected diffusion of nitrogen and carbon. In the ...
The further optimisation and improvement of the efficiency of internal combustion engines require the realisation of new technologies leading to a distinctively faster warm-up behaviour of the coolant and lubricants as well as of the engine components after a cold start. In order to achieve reduced fuel consumption and exhaust gas emissions with the help of heat management, the design criteria of innovative cooling systems need to be reflected and adapted to future requirements. The use of intelligent components within the cooling system, such as the 'Stand Alone Rotary Valve' as a thermostat's substitute or the use of coolant pumps with a rotary valve integrated into the pump's inlet chamber, offer new ways to realise in a decisively quicker and more flexible way the appropriate heating up and cooling down procedures at varying driving conditions. A description of both of the intelligent components for the cooling system is given in this paper. The ...
1. Cyanide degradation: Of the cyanide- and thiocyanate-degrading bacteria, Burkholderia cepacia and Pseudomonas spec. were the most effective. 2. Biosorption: Of the isolates suited for biosorption of heavy metals, 597-A (non-identifiable) and 597-A2 (Aspergillus fumigatis) had the biggest potential. The sorption capacity of the fungi for metals varied with the C source used for their growth: apple juice > molasses > glucose. The fungi are not cyanide-sensitive and can even degrade cyanide. Living biomass had better metal sorption efficiencies than dead mycelium. The biosorption rates in waste water were usually higher than in broth. Depending on the metal composition and concentrations and on the exposure time and volume of the mycelia, up to 85 % of the initial concentration was removed from the liquid phase. The capacity of different biomasses for the sorption of metal mixtures was between 65 and 80 mg/g of dry matter depending on the experimental ...
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.)
In cooperation with NRPB, the specifications of the mainframe COSYMA version 95/1 and the PC COSYMA version 2.0 were prepared and the corresponding modifications implemented. Important improvements are dose-rate dependent models for deterministic health effects, the time dependent efficiency of stable iodine tablets, the extension of data bases for the inclusion of activation products, and supplementary evaluation programs. PC COSYMA has been completed by an economics module, further options in the ingestion pathways, and a graphics package for presenting assessment results. COSYMA has been applied for probabilistic dose assessments within paramter studies and special investigations of EPR concepts. RODOS, the real-time on-line decision support system for nuclear emergency management, has been further developed with the aim of the first pilot version 2.0 for pre-operational application in the second half of 1995. At present, some 20 institutes in the EU, 8 institutes in Russia, Belarus ...
Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle fatigue, crack initiation was most likely caused by inclusions like Titanium Carbonnitrides or Aluminium Oxides. A micro mechanical model for the crack initiation by inclusions was developed. Another model was developed to describe the influence of these inclusions on the lifetime. A weakest-link model, using the statistical distribution of inclusions and surface flaws, was used to describe the endurance limit. (orig.) [German] Es wurden Woehlerlinien unter Zug-Druck-, Torsions- sowie kombinierter phasengleicher und phasenverschobener Zug-Druck- und Torsionsbelastung fuer glatte und gekerbte Proben des Stahls 100Cr6 (SAE 52100) im bainitischen Zustand erstellt. Im Bereich der Langzeitermuedung gingen die Risse meistens von ...
In addition to dependable starting - even at extreme sub-zero temperatures - the starting behaviour of modern commercial vehicle diesel engines is increasingly being evaluated on the basis of HC emissions in the starting and warm-up phases. To improve their performance in this respect, most small and medium-sized diesel engines (with a capacity of 3 to 12 litres) are therefore equipped with intake air heating systems. As an alternative to high-performance, fuel-burning flame start systems, the automotive industry supplier Beru has now developed a new type of self-regulating electric heating element which not only ensures dependable starting with short heating times but also allows drastic reductions in HC emissions. (orig.) [Deutsch] Das Startverhalten moderner Nutzfahrzeug-Dieselmotoren wird, ergaenzend zum Hauptmerkmal des sicheren Starts auch bei extremen Minustemperaturen, zunehmend anhand der HC-Emission in der Start- und Warmlaufphase ...
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 ...
A model for combined mass and heat transfer during nonisothermal gas absorption in a two-phase gas- liquid bubbly medium with a high gas content and/or large times of gas-liquid contact is suggested. Diffusion and thermal interactions between bubbles is taken into account in the approximation of a cellular model of a bubbly medium whereby a bubbly medium is viewed as a periodic structure consisting of identical spherical cells with periodic boundary conditions at a cell boundary. Distribution of concentration of dissolved gas, temperature distribution in liquid and coefficients of mass and heat transfer during nonisothermal absorption of a soluble pure gas from a bubble by liquid are determined. In the limiting case of absorption without heat release the derived formulas recover the expressions for isothermal absorption. (orig.). With 1 fig., 1 tab. [Deutsch] Es wird ein Modell vorgestellt, das den kombinierten Waerme- und Stoffaustausch waehrend der ...
This thesis deals with the analysis of dominant loss mechanisms in direct methanol fuel cells (DMFC) and hydrogen fed polymer electrolyte membrane fuel cells (PEFC) by means of experimental characterization and modeling work. Due to different fuels used in these two fuel cell types, the dominant loss mechanisms are different in their nature. All in-situ characterization techniques that are used in this work are based on a novel test fuel cell with embedded reference electrodes. The first part of this work presents a new concept for realizing a reference electrode configuration in a polymer electrolyte membrane fuel cell by means of laser ablation. The laser beam is used to evaporate a small gap into the electrode surface of a catalyst coated membrane (CCM) to isolate the reference electrode from the working/counter electrode (WE/CE). This method enables the simultaneous ablation of the electrodes on both sides of the CCM because the membrane is transparent for the laser beam. ...
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.)
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.
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.)
Purpose: To visualise the vessel wall of the descending thoracic aorta using magnetic resonance imaging. To evaluate the diagnostic potential of tailored T{sub 1}-weighted sequences with contrast enhancement to assess systemic atherosclerotic disease. Methods: This study was performed on a clinical 1.5 Tesla scanner using a gradient strength of 30 mT/m and the phased array spine coil. A cadaver was examined to optimise a magnetic resonance imaging (MRI) protocol to evaluate atherosclerotic aortic wall disease. The acquired MR images were compared to gross specimens and histology. Subsequently seven patients who had undergone transesophageal ultrasound (TEU) with detailed assessment of the descending thoracic aorta were examined with MRI. The optimised protocol included untriggered and fat suppressed T{sub 2}-weighted turbo spin echo sequences and ECG-triggered and fat suppressed T{sub 1}-weighted spin echo sequences before and after iv administration of Gd-DTPA. ...
For purposes of assessing the dumpability of wastes, Article 1 - Ordinance on the Environmentally Responsible Landfilling of Household Wastes (AbfAblV) - of the Ordinance on the Environmentally Responsible Landfilling of Household Wastes and Biological Waste Treatment Plants defines classificaton criteria for biologically and mechanically treated wastes destined for landfilling. The practical experiences that have been gathered with these classification criteria and values were evaluated in a questionnaire-based survey. This was done in particular for the purpose of verifying and validating proposals on the methodology of respiration and fermentation tests. A general finding has been that the application and implementation of the regulations of the AbfAblV is fraught with difficulties. This is evident for one thing in the frequency of analyses and for another in the difficulty of complying with the limit values of the classification criteria. The authors are in support of demands that ...
Minimally invasive thermotherapies for focal tissue destruction on the basis of laser-, microwave-, focused ultrasound-, or cryogeninduced changes of tissue temperature represent an alternative to surgical tissue ablation, particularly in the treatment of tumors. The thermotherapy modalities listed necessitate indirect guidance and monitoring, since they often do not lend themselves to immediate visual control. In the brain, in head and neck tumors, in the liver, and in the prostate, MRI reliably and accurately delineates both the positions of interstitial thermotherapy applicators and - in contrast-enhanced, T1-weighted images - the perfusion defects in tissue necrosis induced by thermotherapy. The transfer of results of in-vitro and in-vivo model studies to assess interstitial temperature and lesion development during thermotherapy to the actual treatment of patients, however, is still in an initial phase. Further development of both rapid MRI sequences and MRI ...
Purpose: In vitro evaluation of possible deflection and heating of present-day prosthetic heart valves, 12 technical and 5 biological, were investigated using a 1.5 Tesla Siemens Vision system. Deflection was measured at the edge of a 1.5 Tesla superconducting magnet. Each valve was then submerged in a vial of a 1/1 electrolyte solution and temperature was measured before and after imaging with a turbo-spin-echo sequence (TR 5200 ms, TE 138 ms, Flip angle 180 C, acquisition time 10.5 minutes, length of echo train 29). MR imaging was performed with phase encoding parallel and perpendicular to the plane of the valves. Results: None of the investigated prosthetic heart valves was deflected. The maximal observed temperature rise was 0.5 C. During MR investigation of the prostheses, artifacts caused by metallic parts were less evident using a spin-echo sequence than a gradient-echo sequence. Conclusions: Patients with the tested present-day prosthetic heart valves can ...
Physico-chemical characterizations performed on samples of 100Cr6 steel implanted both with boron and nitrogen revealed the formation of boron nitride along with the following new phases: Fe{sub 1-x}(B, N), Fe{sub 2-x}(B, N) and Fe{sub 3-x}(B, N). A thorough analysis of boron NITRIDE (5BN) indicates that a low ion current density (3 {mu}A.cm{sup -2}) in the case of the boron plus nitrogen sequence favours the formation of sp{sup 2} bonds (hexagonal-BN) while a higher ion current density (6{mu}A.cm{sup -2}) promotes sp{sup 3} bonds (cubic-BN) in the opposite sequence. Tribological tests carried out on these samples revealed that nitrogen and boron implantations do not lead to any significant improvement of friction and wear at variance with the results obtained by others authors. However, on a set samples accidentally contaminated with carbon during implantation, we noticed a considerable improvement of these tribological parameters. As this pollution is commonly ...
Materials and methods: 12 patients with 22 coronary bypass grafts underwent intraoperative flow quantification using the transit time ultrasound method. These values were compared to postoperative MR phase shift measurements. Flow measurements were performed preoperatively in 28 coronary arteries of 20 patients. For flow measurement, we used a velocity-encoded k-space segmented gradient echo sequence with a temporal resolution of 110 or 125 ms, respectively. 6-8 pase shift images could be acquired during one cardiac cycle. Results: There was a significant correlation between intraoperative and flow measurements using velocity-encoded MR imaging (r=0.76, p<0.0001, t-test). Flow volumes determined by MR imaging were systematically larger than those determined by the transit time ultrasound method. Mean flow in coronary arteries was reduced in severely stenosed vessels (>70%) compared to normal vessels. Intra- and interobserver variability were 10.5 and ...
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.).
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
1. In order to carry out isothermic crystal growth experiments of YBCO the 123 primary crystallization field was determined by means of phase diagram investigations and crystal growth experiments at different oxygen partial pressure. 2. YBCO single crystals of high crystallographic perfection were grown and conclusions on the flux pinning mechanism were drawn. 3. By means of Liquid Phase Epitaxy (LPE) single crystalline (Tc{approx}90 K; {Delta}T{<=}0.5 K) c- and a,b- YBCO fils have been prepared on NdGaO{sub 3} and LaGaO{sub 3} substrates. The films were characterized structurally and magnetically. 4. Our fist melt textured YBCO ``single crystals`` possess intracrystalline critical current densities >10{sup 4} A/cm{sup 2} at B{<=}2T. The irreversibility inductions are {<=}6 T at 77 K. A simple demonstrator was constructed together with the IFW Dresden and a growth model was developed. 5. Using above all torque magnetometer ...
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 ...
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 ...
Top quark is extremely sensitive to non-standard CP violating phases. General strategies for exposing different types of phases at the NLC are outlined. SUSY phase(s) cause PRA in $t\\to Wb$. The transverse polarization of the $\\tau$ in the reaction $t\\to b\\tau\
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, ...
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 ...
The purpose of this work was to establish a new binary data base by compiling the activity coefficients of plutonium and uranium at oxidation state +IV to better account for media effects in the liquid-liquid extraction operations implemented to reprocess spent nuclear fuel. Chapter 1: first reviews the basic thermodynamic concepts before describing the issues involved in acquiring binary data for the tetravalent actinides. The difficulties arise from two characteristics of this type of electrolyte: its radioactive properties (high specific activity requiring nuclearization of the experimental instrumentation) and its physicochemical properties (strong hydrolysis). After defining the notion of fictive binary data, an approach based on the thermodynamic concept of simple solutions is described in which the activity coefficient of an aqueous phase constituent is dependent on two parameters: the water activity of the system and the total concentration of dissolved ...
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 ...
Purpose: Measurement of the oscillating CSF flow in the spinal canal (SC) of healthy volunteers and in patients with post-traumatic syringomyelia (PTS) using an optimized MRI protocol as well as to determine whether stenosis induced velocity changes are detectable using MRI. Methods: In 68 healthy volunteers quantitative studies of CSF flow in the cervical, thoracic, and lumbar regions were performed. First, an optimized sequence was developed and tested in 19 volunteers using four different flow-encoding velocities (4, 8, 12, 16 cm/s). Secondly, the optimized sequence was employed in 49 volunteers to measure the different CSF patterns in the cervical, thoracic, and lumbar spinal canals (CSC, TSC, LSC). Part three of the study, in which patients with PTS are being examined is still underway. We measured the maximum velocity (cm/s), the pixel area (mm{sup 2}), and the stroke volume (ml/s). Using a flow model the velocities prior to and after compression with 5 different power levels ...
Despite their simplicity, diatomic molecules of first row elements can exhibit very complex phase diagrams. Determination of the phase diagrams can be further complicated by the existence of hysteretic molecular phases that can be observed over large regions of coexistence. Here we present evidence for a previously unreported molecular phase of nitrogen existing at room temperature at least over the range of 33-74 GPa. Our measurements show that sample history may have a significant impact on the thermodynamic states accessed by the molecular nitrogen solid and, by extension, also on the established phase diagram.
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...
In connection with the different cyclical strengths of the two-phase (#alpha# + #beta#) titanium alloy in the case of the acicular and rounded formations of the #alpha#-phase, we have studied, employing the X-ray diffraction method, the phase composition of the alloy and the influence of heat treatment upon it. Using the method of electronic fractography, we examined the fractures in samples destroyed by the asymmetric twisting, in order to find out why the durability of the alloy is dependent upon the #alpha# - phase structure. It has been found that in the BT22 alloy, the decay the #beta#-phase may proceed in two ways; either with the formation of the martensite #alpha#'-phase of the acicular shape or with the separation of the non-martensite round-shaped #alpha#-phase. The character of the phase transformations #beta# ...
The Fourier transform of cosmological density perturbations can be represented in terms of amplitudes and phases for each Fourier mode. We investigate the phase evolution of these modes using a mixture of analytical and numerical techniques. Using a toy model of one-dimensional perturbations evolving under the Zel'dovich approximation as an initial motivation, we develop a statistic that quantifies the information content of the distribution of phases. Using numerical simulations beginning with more realistic Gaussian random-phase initial conditions, we show that the information content of the phases grows from zero in the initial conditions, first slowly and then rapidly when structures become non-linear. This growth of phase information can be expressed in terms of an effective entropy: Gaussian initial conditions are a maximum entropy realisation of the ...
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.)
The phase space of quantized systems that contain tachyons has been investigated. Interpretation difficulties and unexpected divergences are found when it is considered the volume of Lorentz-invariant phase space. These problems can be overcome, however, at the expense of Lorentz invariance.
The phase space of quantized systems that contain tachyons has been investigated. Interpretation difficulties and unexpected divergences are found when we consider the volume of Lorentz-invariant phase space. These problems can be overcome, however, at the expense of Lorentz invariance.
cdc18+ of Schizosaccharomyces pombe is a periodically expressed gene that is required for entry into S phase and for the coordination of S phase with mitosis. cdc18+ is related to the Saccharomyces...Full Text Available
Phase 2 of the four phase NASA/DoD Aerospace Knowledge Diffusion Research Project was undertaken to study the transfer of scientific and technical information (STI) from government to the aerospace industry and the role of librarians and technical informa...
Various measurement tools that are used in chaos theory were applied to analyze two-phase pressure signals with the objective of identifying and interpreting flow pattern transitions for two-phase flows in a small, horizontal rectangular channel. These me...
The authors present differential scanning calorimetry (DSC) and in situ Moessbauer spectroscopy results for Metglas ribbons, to which different heat treatments were made. The Curie temperature of the amorphous phase is determined and the evolution of the magnetic field of this phase is studied as a function of temperature
Previous studies have shown that iterative in-line x-ray phase retrieval algorithms may have higher precision than direct retrieval algorithms. This communication compares three iterative phase...Full Text Available
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 ...
The heating history of a droplet during its flight can be divided into two phases: (a) the initial phase when evaporation, although it occurs, does not change the heat balance of the droplet much (the case considered in our previous paper and (b) the final phase when the cooling due to evaporation balances the heat flux from the plasma. The later phase is considered in Chen's comment. In our reply, a very straightforward consideration demonstrates that even in the final phase of the droplet flight, the 'rocket' effect can be significant. (reply)
The phase transition is a performance measure of the sparsity-undersampling tradeoff in compressed sensing (CS). This letter reports, for the first time, the existence of an exact phase transition for the $\\ell_1$ minimization approach to the complex valued CS problem. This discovery is not only a complementary result to the known phase transition of the real valued CS but also shows considerable superiority of the phase transition of complex valued CS over that of the real valued CS. The results are obtained by extending the recently developed ONE-L1 algorithms to complex valued CS and applying their optimal and iterative solutions to empirically evaluate the phase transition.
Recessive mutations of the early phase change (epc) gene in maize affect several aspects of plant development. These mutations were identified initially because of...Full Text Available
We investigated phase transition of ilmenite-type AgSbO3 to pyrochlore by post-heat treatment and the synergy effect of the mixed phases of AgSbO3 on the photocatalytic activities to enhance the activities. The AgSbO3 with an ilmenite structure was prepared by a cation-exchange method. Phase transition from the ilmenite to pyrochlore occurred by proper control of post-heat treatment. The sample that was obtained by post-heat treatment of ilmenite-type AgSbO3 at 660^oC for 3h consisted of both of the ilmenite and pyrochlore phases, and the sample at 685^oC for 4h mainly consisted of the pyrochlore phase. Together with an increase in the ratio of the pyrochlore phase, the optical absorption spectra blue-shifted. The band gaps of single phases of the ilmenite and the pyrochlore were 2.4 and 2...
... of a secondary standard (VCO) locally available. ... phase of the local secondary standards to the 10-min average of the phase of ... I3a - - \\.-e-~--. ...
... and high-quality photospheric-phase Type II SN spectra to constrain core- collapse SN explosions, massive star evolution, and distances in the Universe ...
The aim of this paper is to present the phase-space properties of the systems that contain bradyons, luxons and tachyons. It is shown that particularly at low energy, these properties are quite different from the well-known properties of bradyons.
The morphological aspects of ternary phase formation during the Pd-GaAs reaction have been studied by application of transmission electron microscopy (TEM) and Rutherford backscattering (RBS) techniques. The TEM images show that the first product phase, ''phase I'', forms during deposition of Pd onto (100) GaAs and exhibits the preferred orientation (0001)/sub I/ approx. // (01 anti 1)/sub GaAs/. In the presence of unreacted Pd, the second phase, ''phase II'', nucleates at large-angle grain boundaries in the phase I film as the annealing temperature increases above approx.250C. Energy dispersive analysis of x-rays and RBS suggest the nominal compositions Pd3GaAs and Pd4GaAs for phases I and II, respectively.
Halothane, chloroform, and carbon tetrachloride, in the vapor and liquid phases, stimulate the water receptor of the blowfly Phormia regina. There are three successive phases of response to long-lasting...Full Text Available
This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low ...
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 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 ...
In order to understand the detail transient two-phase flow structure, more advanced two-phase flow instrumentation is required. One advanced technique for flow visualization is real-time neutron radiography. Reconstruction method of visualized radiographic image of liquid metal two-phase flow generated by the real-time neutron radiography system is proposed in this paper. Image processing techniques for noise reduction and image enhancement are discussed in detail. (author).
In order to understand the detail transient two-phase flow structure, more advanced two-phase flow instrumentation is required. One advanced technique for flow visualization is real-time neutron radiography. Reconstruction method of visualized radiographic image of liquid metal two-phase flow generated by the real-time neutron radiography system is proposed in this paper. Image processing techniques for noise reduction and image enhancement are discussed in detail. (author).
Outline: Discuss far-side weld problem and phased array techniques applied. Describe laboratory work on flawed piping specimens using L- and S-wave arrays and provide synopsis of results. Discuss conclusions ofr capability of phased array as applied to austenitic welds. Research Approach: Evaluate phased arrays on unifornly-welded piping specimens. Apply best methods to non-uniform welds. Correlate acoustic responses as function of weld microstructures.
In a three-phase tri-axial cable, the magnetic interaction between the phases makes the loss measurement by an electromagnetic method very complex. We developed the theoretical background showing that three-phase AC loss measurements by the electromagnetic method are, in principle, possible. We then implemented this theory in practical measurements on a 3 m long, tri-axial cable fabricated from RABiTS (rolling-assisted biaxially textured substrate) coated conductor. Initially, the proposed measurement technique was implemented in the simpler cases when the three cable phases are 180"0 out of phase, i.e. (0"0, 180"0, 360"0) or (0"0, 360"0, 180"0) rather than (0"0, 120"0, 240"0) as in a traditional three-phase system. For these cases, the currents in the phases are either in phase (360"0 phase ...
This paper describes phase-retrieval approaches in music by focusing on the particular case of the cyclic groups (beltway problem). After presenting some old and new results on phase retrieval, we introduce the extended phase retrieval for a generalized musical Z-relation. This concept is accompanied by mathematical definitions and motivations from computer-aided composition. We assume from the reader basic knowledge of groups, topological groups, group algebras, group actions, Lebesgue integration, convolution products, and Fourier transform.
The results of real-time neutron diffraction measurements during the superconducting phase formation process in the Bi(Pb)-Sr-Ca-Cu-O system are reported. A Sr-Ca-Cu-O type precursor, with the same stoichiometry as the 2223 phase, was used as starting material, and the temperature range favorable to the formation of the 2223 phase was investigated. The diffraction patterns were processed by a multiphase Rietveld refinement. The formation and decomposition of the 2201 and 2212 phases were directly observed. Experimental evidence on the existence of a partially melted phase in the range 855-860[degrees]C, involved in the formation of the 2223 phase, is discussed. 14 refs., 9 figs., 1 tab.
The results of real-time neutron diffraction measurements during the superconducting phase formation process in the Bi(Pb)-Sr-Ca-Cu-O system are reported. A Sr-Ca-Cu-O type precursor, with the same stoichiometry as the 2223 phase, was used as starting material, and the temperature range favorable to the formation of the 2223 phase was investigated. The diffraction patterns were processed by a multiphase Rietveld refinement. The formation and decomposition of the 2201 and 2212 phases were directly observed. Experimental evidence on the existence of a partially melted phase in the range 855-860 degrees C, involved in the formation of the 2223 phase, is discussed. 14 refs., 9 figs., 1 tab.
Apart from conventional phase transitions driven by the thermal effects, quantum phase transitions generated by quantum fluctuations have their own mechanisms that are reflected in critical phenomena. Quantum phase transitions have an origin from spontaneous symmetry breaking commonly to thermal phase transitions. Even in this case, inherent quantum fluctuations substantially modify and yield new aspects. Quantum phase transitions have, however, another mechanism caused by topology changes, which gives completely new characters. Recently, a mechanism which connects these two has been found. Proimities from first-order transitions and phase separatins as well as from multiphase coexistence also generate characteristic and unconventional quantum criticalities. Understanding novel quantum criticalities offers a firm basis of recent active researches on fields such ...
Here we reported a two-step procedure for preparing a novel polymeric based solid-solid phase change heat storage material. Firstly, a copolymer monomer containing a polyethylene glycol monomethyl ether (MPEG) phase change unit and a vinyl unit was synthesized via the modification of hydrogen group of MPEG. Secondly, by copolymerization of the copolymer monomer and phenyl ethylene, a novel polymeric based solid-solid phase change heat storage material was prepared. The composition, structure and properties of the novel polymeric based solid-solid phase change material were characterized by IR, "1H NMR, DSC, WAXD, and POM, respectively. The results show that the novel polymeric based solid-solid phase change material possesses of excellent crystal properties and high phase change enthalpy.
A new technique has been developed for the measurement of steam mass flowrate, water mass flowrate and total enthalpy of two-phase fluids produced from geothermal wells. The method involves precisely metered injection of liquid and vapor phase tracers into the two-phase production pipeline and concurrent sampling of each phase downstream of the injection point. Subsequent chemical analysis of the steam and water samples for tracer content enables the calculation of mass flowrate for each phase given the known mass injection rates of tracer. This technique has now been used extensively at the Coso geothermal project, owned and operated by California Energy Company. Initial validation of the method was performed at the Roosevelt Hot Springs geothermal project on wells producing to individual production separators equipped with orificeplate flowmeters for each ...
Lithium ammonium sulfate (LAS) undergoes a phase transition at Tsub(c1) = 459.5deg K from a paraelectric phase (phase 1) to a ferroelectric phase (phase II) and again at Tsub(c2) = 283deg K to a polar ferroelastic phase (phase III). Proton spin lattice relaxation investigations in the temperature range 480-77deg K at 10 MHz show discontinuous changes in Tsub(1) at the transition temperatures, indicating first order phase transitions. The absence of the slow motion region (#omega#sub(not)tausub(not)>>1) shows that the ammonium ions are reorienting fast enough to keep the resonance absorption line narrow down to liquid nitrogen temperatures. The possibility of a second minimum and a low activation energy, Esub(a) = 2.659 kcal/mole, in phase III suggest the possibility of tunnelling of the protons ...
Phase transformations occuring during cold deformation in hardened #alpha#+#beta# titanium alloy of the Ti-Al-Mo-Zr-Sn-Si system with 10% summary content of alloying elements are studied by X-ray diffraction analysis. Two stages of trapsformation of metastable #alpha#''-phase are found. A conclusiop is made that ability of the alloy containing #alpha#''-phase to cold deformation is determined by the presence of favourable texture, by high degree of metastability and by volume portion of #alpha#''-phase in the alloy structure.
In FY 1984 three specific tasks which are all related to not-well-understood two-phase phenomena of importance to LWR accidents have been identified under the program. These three tasks are: (1) inverted annular flow experiments and modeling; (2) hot leg U-bend two-phase flow simulation study; and (3) development and evaluation of two-phase flow scaling criteria. Some of the important results obtained under Tasks (1) and (2) are reported in this paper.
The author shows in this paper an interesting relation between elementary and topological excitations in the antiferromagnetic and d-wave superconducting phases of the t-J model at two dimensions. The topological spin and charge excitations in one phase have the same dynamics as elementary excitations in the other phase, except the appearance of energy gaps. Moreover, the transition from one phase to another can be described as a quantum disordering transition associated with the topological excitations. Based on the above picture, a plausible phase diagram of t-J model is constructed.
Crystal structure of monoclinic telluric acid ammonium phosphate (TAAP) has been studied by an X-ray diffraction method in the paraelectric phase at 333 K and in the ferroelectric phase at room temperature. It is confirmed that the space group in the paraelectric phase is P2/n. Comparison of the results between the two temperatures suggests that the plane which is made by the PO{sub 4} tetrahedron linked by hydrogen bonds has an important role for the ferroelectric phase transition. This plane is almost parallel to the direction of spontaneous polarization.
CIRNAT, a one-dimensional code for natural circulation analysis, was described. The homogeneous approach was adopted for the two-phase flow regime and different heat transfer regimes were considered. The code was exhaustively tested for one-phase flow systems. For two phase flows a boiling/condensing system was simulated. The results are qualitatively correct but the oscillations observed at the system were not captured by the model. Other two-phase flow tests must be done to show the limits of the homogeneous approach before the introduction of a more complex model. (author)
CIRNAT, a one-dimensional code for natural circulation analysis, was described. The homogeneous approach was adopted for the two-phase flow regime and different heat transfer regimes were considered. The code was exhaustively tested for one-phase flow systems. For two phase flows a boiling/condensing system was simulated. The results are qualitatively correct but the oscillations observed at the system were not captured by the model. Other two-phase flow tests must be done to show the limits of the homogeneous approach before the introduction of a more complex model. (author)
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.)
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)
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 ...
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 made between the ...
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 ...
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 ...
The Utility PhotoVoltaic Group (UPVG), supported by member dues and a grant from the US Department of Energy, has as its mission the acceleration of the use of cost-effective small-scale and emerging large-scale applications of photovoltaics for the benefit of electric utilities and their customers. Formed in October, 1992, with the support of the American Public Power Association, Edison Electric Institute, and the National Rural Electric Cooperative Association, the UPVG currently has 90 members from all sectors of the electric utility industry. The UPVG's efforts as conceived were divided into four phases: Phase 0--program plan; Phase 1--organization and strategy development; Phase 2--creating market assurance; and Phase 3--higher volume purchases. The Phase 0 effort developed the program plan and was completed early in 1993. The Phase 1 ...
The two-phase flow program is directed at understanding the hydrodynamics of two-phase flows. The two-phase flow regime is characterized by a series of flow patterns that are designated as bubble, slug, churn, and annular flow. Churn flow has received very little scientific attention. This lack of attention cannot be justified because calculations predict that the churn flow pattern will exist over a substantial portion of the two-phase flow zone in producing geothermal wells. The University of Houston is experimentally investigating the dynamics of churn flow and is measuring the holdup over the full range of flow space for which churn flow exists. These experiments are being conducted in an air/water vertical two-phase flow loop. Brown University has constructed and is operating a unique two-phase flow research facility specifically designed to address flow ...
Commissioning of a Pressurized heavy water reactor (PHWR) plant of NPCIL involves three phases viz phase-A which consist of pre-criticality activities such as hydro test, air hold test, no load test of motors etc., phase-B consist of criticality and post criticality physics experiments. The phase-C, which is considered the major phase, consist of initial power raise to about 10 % , TG rolling, synchronization, going to significant power in steps and performance tests such as load rejection tests from various power levels. In order to have smooth commissioning for the Phase-C, an integrated team consisting of engineers from various design and analysis groups of NPCIL headquarters was formed to participate along with site O and M engineers, closely observe and coordinate phase-C commissioning activities. During this commissioning some major ...
In order to study the two-phase natural circulation and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using two different thermal-hydraulic loops. The main focus of the experiment was the two-phase flow behavior in the hot-leg U-bend typical of BandW LWR systems. The first group of experiments was carried out in the nitrogen gas-water adiabatic simulation loop and the second in the Freon 113 boiling and condensation loop. Both of the loops have been designed as a flow visualization facility and built according to the two-phase flow scaling criteria developed under this program. The nitrogen gas-water system has been used to isolate key hydrodynamic phenomena such as the phase distribution, relative velocity between phases, two-phase flow regimes and flow termination mechanisms, whereas the Freon ...
We consider two-dimensional large N gauge theory with D adjoint scalars on a torus, which is obtained from a D+2 dimensional pure Yang-Mills theory on T^{D+2} with D small radii. The two dimensional model has various phases characterized by the holonomy of the gauge field around non-contractible cycles of the 2-torus. We determine the phase boundaries and derive the order of the phase transitions using a method developed in an earlier work (hep-th/0910.4526), which is nonperturbative in the 'tHooft coupling and uses a 1/D expansion. We embed our phase diagram in the more extensive phase structure of the D+2 dimensional Yang-Mills theory and match with the picture of a cascade of phase transitions found earlier in lattice calculations (hep-lat/0710.0098). We also propose a dual gravity system based on a Scherk-Schwarz compactification of a D2 brane wrapped on a ...
Based on a recently introduced phase X-ray imaging approach, a dual-detector prototype was developed for in-line X-ray phase imaging and phase retrieval utilizing a micro-focus X-ray source and two computed radiography (CR) cassette detectors. The system was built on a horizontal optical rail to facilitate manual adjustment of the positions of the X-ray source, the sample and the detectors. The novel design of the detector-1 is essential, it detects a portion of radiation to form an attenuation image; allows the rest of radiation to reach the detector-2 to form a phase contrast image, and the two images are used to retrieve a phase map. The two detectors are balanced for optimal phase-retrieval with reasonable radiation dose to the object to be imaged. The system was examined in terms of the linearity, the fractions of the X-ray photons detected by the two ...
We report on a hard X-ray phase imaging microscopy (a phase-difference microscopy) that consists of an objective and a transmission grating. The simple optical system provides a quantitative phase image, and does not need a wave field mostly coherent on the objective. Our method has a spatial resolution almost same as that of the absorption contrast microscope image obtained by removing the grating. We demonstrate how our approach provides a phase image from experimentally obtained images. Our approach is attractive for easily appending a quantitative phase-sensitive mode to normal X-ray microscopes, and has potentially broad applications in biology and material sciences.
The application of multi-objective genetic algorithms for green building design in two phases were presented in order to better help designers in the decision-making process. The purpose is to minimize two conflicting criteria: the life-cycle cost and the life-cycle environmental impact. Environmental impact criteria examined include energy and non-energy natural resources, global warming, and acidification. Variables focus on building envelope-related parameters. The application of multi-objective genetic algorithms is divided into two phases. The first phase intends to help designers in understanding the trade-off relationship between the two conflicting criteria. The second phase intends to refine the performance region that is of the designer's interest. The results after the two-phase application of the multi objective genetic algorithm were then presented. 13 refs., 4 ...
A series of #alpha#-sialon (#alpha#') compositions containing mixed stabilising cations were prepared, by introducing additional CaO to a basic Sm #alpha#-sialon compositions. The thermal stability of these Sm-Ca-containing #alpha#-sialon phases was investigated using XRD, SEM and EDXS techniques. It was found that the addition of calcium into the Sm #alpha#-sialon systems greatly improved the stability of the #alpha#-sialon phases. Calcium was found to be incorporated into the #alpha#-sialon structure, coexistent with the samarium, and partitioning of the calcium and samarium was observed between the #alpha#' phase and grain boundary phases. This indicates a technique which may be used to improve the thermal stability of the #alpha#' phase while maintaining good refractory phases at the sialon grain boundaries.
A simple tube-in-tube heat exchanger system for thermal energy storage employing stearic acid as PCM has been investigated. The performance and heat transfer characteristics of such a system were studied. Phase transition temperature range and times were measured and the speed of the phase transition front was computed. The melting front was found to move in the radial direction inward as well as in the axial direction from the top toward the bottom of the phase change material PCM tube. The speed of the melting front is enhanced by a convection heat transfer mechanism in the melted PCM. The heat transfer rate and, consequently, phase transition time can be altered by changing the water inlet temperature to the heat exchanger. In addition, a faster phase transition is realized by placing the heat exchanger in a horizontal position rather than a vertical one. (Author)
The advent, in the near future, of compact X-ray sources like Thomson Back-Scattering (TBS) will allow the clinical application of advanced X-ray imaging techniques, such as phase contrast, with higher sensitivity and lower impact in terms of dose delivery. In this work, we theoretically investigated the possibility of using such sources for phase contrast imaging of micro-calcifications included in a breast tissue. In our study we analyzed the phase and amplitude distribution of the TBS source and we showed that this source can be used for phase contrast imaging since the source coherence at the sample position is sufficiently high for achieving good contrast and micrometer spatial resolution. Indeed the spatial coherence of a TBS source is closer to that of a synchrotron radiation source, and much better than that of a laboratory source. Moreover, we showed the advantages of phase ...
Ternary diagrams are commonly used to provide a graphic representation of equilibrium fluid phase behavior for systems as diverse as distillation columns and miscible gas floods of oil reservoirs. The phase envelope, and the position of the critical point on it, are important to enhanced oil recovery engineers who are involved with miscible gas flood design. In the past, phase equilibrium data were laboriously plotted on the ternary diagram and special graphic techniques were utilized to locate the critical point on the phase envelope. This work presents a computerized curve fitting method to generate the phase envelope from a given set of phase equilibrium data and then use the tie-line slopes to position the critical point. Experimental data are included and show excellent agreement with this new method.
Ternary diagrams or pseudo ternary diagrams are commonly used to provide a graphical representation of equilibrium fluid phase behavior for systems as diverse as distillation columns and miscible gas floods of oil reservoirs. The phase envelope and the position of the critical point on it are important to enhanced oil recovery engineers who are involved with miscible gas flood design. In the past, phase equilibrium data were laboriously plotted on the pseudo ternary diagram and special graphical techniques were utilized to locate the critical point on the phase envelope. Presented in this article is a computerized curve fitting method to, firstly, generate the phase envelope from a given set of phase equilibrium data and then use the 'tie-line slopes' to position the critical point. Experimental data are included and show excellent agreement ...
Recently the authors showed that tetrazolium salts can be obtained during the oxidation of substituted 1,3,5-triarylformazans with potassium permanganate in a two-phase organic solvent-water system. The role of phase-transfer catalyst in this reaction is played by the tetrazolium salt, which is formed in a small amount as the result of oxidation of the formazan at the phase boundary. The method is distinguished by its extreme simplicity. However, the yield of the tetrazolium salts fluctuates within wide limits and does not exceed 62%. This is due to the fact that as the reaction proceeds the pH of the aqueous phase increases from 6 to 12. At the same time it is known that tetrazolium salts are unstable in aqueous alkaline solutions. They found that if the aqueous phase is replaced by aqueous hydrochloric acid (5 wt. %) the yields of the tetrazolium salts (Ia-g) are increased to ...
The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.
The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.
A localization criterion for the crystal-liquid phase transition (PT) is suggested, according to which the PT starts when the ratio E d/k B T reaches a boundary value E d(s)/k B T m, above which a solid phase, and below which, a liquid phase is located in the phase diagram. Here, E d is the energy of the delocalization of an atom, k B is the Boltzmann constant, T is the temperature, and E d(s) is the energy of delocalization for the solid phase at the melting point T m. It is shown that this criterion extends the Lindemann criterion of melting to the case of crystallization, and the L?ven criterion of crystallization to the case of melting. It is shown that the localization criterion suggested is applicable both for the normally melting substances and for the substances melting with a decr...
A localization criterion is proposed for the crystal-liquid phase transition (PT). According to this criterion, the PT begins when the E d/k b T ratio reaches a boundary value E d(s)/k b T m such that a solid phase is present above it and a liquid phase is present below it in a phase diagram. Here, E d is the energy of atom delocalization, k b is the Boltzmann constant, T is the temperature, and E d(s) is the delocalization energy for a solid phase at melting point T m. This criterion is shown to generalize the Lindemann criterion of melting to the case of crystallization and the L?ven criterion of crystallization to the case of melting. This localization criterion is found to be applicable for both normally melting substances and substances that melt with a decrease in the specific volume...
Adjustment of the rf phase in a linear accelerator is crucial for maintaining optimal performance. If phasing is incorrect, the beam will in general have an energy error and increased energy spread. While an energy error can be readily detected and corrected using position readings from beam position monitors at dispersion locations, this is not helpful for correcting energy spread in a system with many possible phase errors. Uncorrected energy spread results in poor capture efficiency in downstream accelerators, such as the Advanced Photon Source's (APS's) particle accumulator ring (PAR) or booster synchrotron. To address this issue, APS has implemented beam-to-rf phase detectors in the linac, along with software for automatic correction of phase errors. We discuss the design, implementation, and performance of these detectors and how they improved APS top-up ...
An iterative phase retrieval algorithm was previously investigated for in-line x-ray phase imaging. Through detailed theoretical analysis and computer simulations, we now discuss the limitations, robustness, and efficiency of the algorithm. The iterative algorithm was proved robust against imaging noise but sensitive to the variations of several system parameters. It is also efficient in terms of calculation time. It was shown that the algorithm can be applied to phase retrieval based on one phase-contrast image and one attenuation image, or two phase-contrast images; in both cases, the two images can be obtained either by one detector in two exposures, or by two detectors in only one exposure as in the dual-detector scheme.
The transformation mechanism of hexagonal delta phase from the disordered bcc gamma phase has not been reported before in the Zr-rich U-Zr alloy system. With the help of X-ray diffraction, transmission electron microscopy (TEM) and high-resolution TEM analyses it was shown that the gamma to delta conversion takes place by the lattice collapse mechanism of omega transformation. It was also ascertained that a higher aging temperature or time promotes the growth of all four variants of the delta phase within a parent gamma grain. In addition, ab initio electronic structure calculations showed that the bcc to hexagonal transformation, involving partial ordering of the parent bcc phase followed by (111) plane collapse, is energetically favorable.
A survey is presented of the principles and practice of tailoring sintering liquid composition and processing cycle to enable crystallisation of intergranular phases in silicon nitride and sialon ceramics. Critical features in sialon ceramics are the O/N balance in residual glasses and post-sintering heat-treatment temperatures to enable nucleation of either intermediate phases at constant composition or oxide phases with re-partitioning of non stoichiometric components in #beta#' or #alpha#' solid solutions. Crystallisation of disilicate phases in non-sialon compositions exemplifies a problem in control of polymorphs with differing atomic volumes. Crystallisation of intergranular phases has an influence mainly on high-temperature mechanical and environmental behaviour of these ceramics. (orig.).
Various measurement tools that are used in chaos theory were applied to analyze two-phase pressure signals with the objective of identifying and interpreting flow pattern transitions for two-phase flows in a small, horizontal rectangular channel. These measurement tools included power spectral density function, autocorrelation function, pseudo-phase-plane trajectory, Lyapunov exponent,s and fractal dimensions. It was demonstrated that the randomlike pressure fluctuations characteristic of two-phase flow in small rectangular channels are chaotic, and governed by a high-order deterministic system. The correlation dimension is potentially a new approach for identifying certain two-phase flow patterns and transitions.
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) ...
Phase contrast X-ray imaging has been studied intensively using X-rays from synchrotron radiation and micro-focus X-ray tubes. However, these studies have revealed the difficulty of this technique's application to practical medical imaging. We have created a phase contrast imaging technique using a molybdenum X-ray tube with a small focal spot size for mammography. We identified the radiographic conditions in phase contrast magnification mammography with a screen-film system, where edge effect due to phase contrast overcomes geometrical unsharpness caused by the 0.1 mm-focal spot of a molybdenum X-ray tube. The edge enhancement due to phase imaging was observed in an image of a plastic tube, and then geometrical configuration of the X-ray tube, the object and the screen-film system was determined for phase imaging of mammography. In order to investigate a ...
This paper describes a long term course of research into the fundamentals of two phase flow regime dynamics that had lead to a differential description of regime properties. The development has included experiment, microscale simulation, and mathematical averaging to produce a dynamic equation for interfacial area.
Staphylococcus aureus preferentially catabolizes glucose, generating pyruvate, which is subsequently oxidized to acetate under aerobic growth conditions. Catabolite repression of the...Full Text Available
The amorphization of a quenched sample of the GaSb-II high-pressure phase was studied at ambient pressure by real-time neutron diffraction in the course of the sample heating from 100 K to room temperature at a rate of 0.4 K min{sup -1}. The transformation to the amorphous state begins at 140 K and is completed near room temperature. The {beta}-Sn type structure was shown to represent only the mean lattice of the high-pressure GaSb-II phase. The superstructure of this phase widely varied with temperature and is caused by the ordered displacement of atoms. The temperature range of the metastable crystalline phase relaxation is divided into three intervals according to the temperature dependence of the tetragonality ratio (c/a). At the boundaries of these temperature intervals, i.e. temperatures T = 170 and 230 K, two second-order phase transitions are observed. Anomalous heat and ...
The amorphization of a quenched sample of the GaSb-II high-pressure phase was studied at ambient pressure by real-time neutron diffraction in the course of the sample heating from 100 K to room temperature at a rate of 0.4 K min-1. The transformation to the amorphous state begins at 140 K and is completed near room temperature. The ?-Sn type structure was shown to represent only the mean lattice of the high-pressure GaSb-II phase. The superstructure of this phase widely varied with temperature and is caused by the ordered displacement of atoms. The temperature range of the metastable crystalline phase relaxation is divided into three intervals according to the temperature dependence of the tetragonality ratio (c/a). At the boundaries of these temperature intervals, i.e. temperatures T = 170 and 230 K, two second-order phase transitions are observed. Anomalous heat and volumetric ...
The flow of water through a dam of fairly arbitrary shape is examined in the limit of large frictional drag on the flow. The relation of the problem to the one-phase Stefan problem and a problem of anodic smoothing is explored. Monotonicity and uniqueness...
Phosphoramidite reagents can phosphitylate guanine bases at the O6-position during solid phase synthesis and serious chain cleavage occurs if the base phosphitylation is not eliminated before the iodine/water...Full Text Available
It is shown that calculation of the anomalous expectation values for the massless Gross-Neveu model in the Hartree-Fock approximation indicates the presence of an ordinary chiral phase transition if the coupling constant has the normal sign (g > 0) and of a different transition of the superconductivity type if g < 0.
A detailed comparative assessment was made of the use of solid-phase-coupled antibodies in radioimmunoassay, by using an assay for human placental lactogen as a model system. The major advantages of...Full Text Available
[Leu]- and [Met]enkephalin from thoracic ganglia of the shore crab Carcinus maenas have been purified to homogeneity by a reversed-phase HPLC procedure. Automated gas-phase sequencing revealed a primary...Full Text Available
The three-dimensional (3-D), multiphase, computational fluid dynamic (CFD) code FLUENT is used to simulated two-phase flow behaviour in a CANDU header manifold under low (natural circulation) flow conditions. This behaviour was previously inferred from experimental data. The CFD simulations reported here are being used to support these inferences and to obtain a better understanding of phase distribution in the header manifold. The simulations seem to show that the vapor-water mixture models in the FLUENT code do not capture properly phase separation in the header and proper phase branching at the header-feeder connections that have been observed in experiments at low flows. The simulations using discrete-phase model in FLUENT, which tracks the pathlines of the individual vapor bubbles in the water continuum phase, show interesting, complicated and, in some ...
During Phase II multi-junction solar cell will be grown on the large grain thin film produced during Phase I on flexible/low cost metal foil substrate. ...
The effect of growth phase on expression of virulence-associated factors was studied by Northern hybridization in an M1T1 clinical isolate of Streptococcus pyogenes. Expression of M...Full Text Available
This cost-effectiveness analysis supports the proposed effluent limitations guidelines and standards for the Metal Products and Machinery Industry (MP and M) Phase I Industry. The report assesses the cost-effectiveness of five regulatory options for indir...
To attain reproducible and stable contacts to compound semiconductor devices, it is necessary to achieve thermodynamically stable phases after the reaction of metals with the compound semiconductor. In this study, the final phases produced by the reactions between GaAs and thin metal films of Co, Rh, Ir, Ni, Pd, and Pt have been investigated. They are identified as MGa for M = Co, Rh, Ni, Pd, and Pt, monoarsenides of Co and Ni, diarsenides of Rh, Ir, Pd, and Pt, and Ir/sub 3/Ga/sub 5/. These phases, if deposited directly onto GaAs, will produce thermally stable contacts. In addition to the identification of these stable phases, analyses of the products of thin-film M/GaAs reactions by transmission electron microscopy, x-ray diffraction, and Rutherford backscattering spectrometry reveal the distribution, grain size, and crystallographic texture of these end phases. Trends in these ...
A solid-phase radioimmunoassay employing 125I-labeled enterotoxins and polystyrene tubes coated with specific antibody has been developed for assaying the relative concentrations of antibodies...Full Text Available
The polymorphic phase behavior of a homologous series of n-saturated 1,2-diacyl phosphatidylethanolamines was investigated by differential scanning calorimetry, 31P-nuclear magnetic resonance, and Fourier...Full Text Available
The Δ- and Λ-isomerism of octahedral metal complexes is employed as a source of chirality for inducing chiral nematic phases. By applying a wide range of chiral metal complexes as a...Full Text Available
The main objective of Phase I of this SBIR project was to demonstrate the feasibility for successful development of an antimicrobial wound dressing based on a hydrogel sustained release matrix. This goal has been achieved. In vitro studies of drug diffusi...
A safety analysis code to design a pressurized water reactor and to obtain the licenses including entire proprietary rights is under development in domestic R and D project. The tasks of KAERI is to develop the constitutive relations including models for defining flow regimes and flow regime related models for inter-phase friction, wall frictions, wall heat transfer, and interphase heat and mass transfer in the two-phase three-field equations. In this paper, the process will be presented for choosing the best flow regime maps which occur in gas-liquid two-phase flow in horizontal and vertical tubes.
A safety analysis code to design a pressurized water reactor and to obtain the licenses including entire proprietary rights is under development in domestic R and D project. The tasks of KAERI is to develop the constitutive relations including models for defining flow regimes and flow regime related models for inter-phase friction, wall frictions, wall heat transfer, and interphase heat and mass transfer in the two-phase three-field equations. In this paper, the process will be presented for choosing the best flow regime maps which occur in gas-liquid two-phase flow in horizontal and vertical tubes.
The phase space beam analyzer is a measurement instrument that is applied in laser technology to perform analyses of the spatial and angular distribution of rays. We are interested in this instrument as a means to characterize non-coherent light sources. In this context, a closer look at the tolerances of this optical instrument was considered useful. Having a so-called quadrupole lens as a key element, the phase space beam analyzer is a device that features anamorphic optical properties. To describe these anamorphic properties, recurrence was made to a description by extended ray-transfer matrices. This formalism allows for an analysis of the alignment tolerances of the phase space beam analyzer and facilitates a study of the sensitivities of the instrument. The analysis is complemented using numerical ray tracing.
Heat transfer and flow characteristics of water boiling flow were experimentally investigated in narrow horizontal rectangular channels with the gaps of 0.6mm-2.03mm. The heat transfer of two-phase boiling flow was weakend in smaller gap. The two-phase friction pressure drop decreased with the gap size and the two-phase friction multipliers were smaller compared with those in normal channels. Correlations to predict te boiling heat transfer coefficients were obtained. (author)
The GERDA experiment is located in the underground Gran Sasso laboratory. The experiment aims at studying the neutrinoless ?? decay of 76Ge. The implementation of the experiment is divided in two consecutive phases. Phase I will allow within one year of data taking to reach a sensitivity limit for the half life of the process of the order of Formula Not Shown years. Phase II, with an increased amount of active material and a background index lower by one order of magnitude than in Phase I, will allow to reach a half life limit of about Formula Not Shown years. In the present paper a brief review of the status of the experiment and its perspectives is given.
... as time delay shifters for large-area phased arrays in military (MILSTAR) as well as commercial (Sky phone and other satellite communication) systems, ...
The authors attemps to confirm a modification of the phase-absprotion method applicable to the study of the decay rate of energy stored in the upper level in the active medium of a CO/sub 2/-laser. The essence of the method is described. Relationships are determined which allow one to obtain the unknown parameters of the experimentally measured phase shift. The work exeprimentally shows the possibility of studying vibratioanl relaxation in the active medium of a CO/sub 2/-laser by the phase-absorption method using both ordinary and isotope-substitued molecules.
In reservoir fluid flow, the situation described by an increase in nonwetting phase saturation followed by an increase in wetting phase saturation causes a relative permeability hysteresis effect that is well known. This paper presents a method which allows the calculation of imbibition relative permeability starting at any saturation. The data required are the drainage curve, the historical maximum non wetting saturation, and a minimum of one additional point on some corresponding experimental imbibition curve. In this development, all imbibition curves are shown to be parallel. Also significant is the fact that the residual nonwetting phase saturation can be calculated without a complete experimental specification of the imbibition curve. 5 refs.
The wide-angle neutron diffractometer recently installed at the HFIR has the capability of performing time-resolved or time-slicing measurements. One of the interesting problem areas the authors have explored using this time-slicing function of the diffractometer is the kinetics of structural changes occurring after a temperature jump across a value at which a first-order phase transition occurs. Two measurements of this sort have been carried out: the phase III to II transition in RbNO_3 and the transition between the alpha and beta phases in Sn.
A model of a solid disordered ortho-parahydrogen mixture with infinite long-range interaction J/sub ij/ between orthomolecules distributed in accordance with a normal law with first moment J/sub 0/ is investigated. It is shown that the introduction of an external electric field gradient ..gamma.. can give rise to a phase transition to an orientational phase. The possible existence of an orientational glass phase is established. The influence of the degeneracy of the hydrogen orthomolecules on the low-temperature thermal properties of these systems is demonstrated, and a condition of stability of the replica-symmetric solution is established. At low temperatures, this solution is stable for a large value of ..gamma.. or J/sub 0/.nctio
A possible novel application of hard x-ray emitted during laser-plasma interaction was discussed. The authors established an Optical Transform Function to study the joint effect of the spectral distribution and temporal profile of the laser-produced x-ray on x-ray phase imaging. Though the laser-produced x-ray pulse duration is short and incoherent, the analysis confirms that the current x-ray phase imaging theory still holds for laser-produced x-ray phase imaging
... Progress: For a one-dimensional two-phase degenerate Stefan problem, it was proved that the boundary and the solutions up to the boundary are C ...
A method of preparing a high temperature superconductor from an amorphous phase. The method involves preparing a starting material of a composition of Bi.sub.2 Sr.sub.2 Ca.sub.3 Cu.sub.4 Ox or Bi.sub.2 Sr.sub.2 Ca.sub.4 Cu.sub.5 Ox, forming an amorphous phase of the composition and heat treating the amorphous phase for particular time and temperature ranges to achieve a single phase high temperature superconductor.
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.
Weakly absorbing materials, such as biological, soft tissues, can be imaged by generating contrast due to the phase shift of X-rays. In the past decade, several methods for X-ray phase imaging were proposed and demonstrated. The performance of X-ray phase imaging is attractive in the field of medical imaging technology, and its development for practical use is expected. Many methods, however, have been developed under the assumption of the use of synchrotron radiation, which is an obstacle to practical use. The method based on Talbot (-Lau) interferometry enables us to use a compact X-ray source, and its development is expected as a breakthrough for medical applications. (author)
A theory of nonunitary-invertible as well as unitary canonical transformations is formulated in the context of Weyl's phase space representations. Exact solutions of the transformation kernels and the phase space propagators are given for the three fundamental canonical maps as fractional-linear, gauge and contact (point) transformations. Under the nonlinear maps a phase space representation is mapped to another phase space representation thereby extending the standard concept of covariance. This extended covariance allows Dirac-Jordan transformation theory to naturally emerge from the Hilbert space representations in the Weyl quantization.
We present results from ab-initio electronic-structure calculations of mechanical properties of the rhombohedral phase of vanadium reported in recent experiments (R Ia), and other predicted high-pressure phases (R Ib and bcc), focusing on properties relevant to dynamic experiments. We find that of the three transitions the largest volume collapse (1.3%) is for the R Ia to R Ib transition. Calculations of the single crystal and polycrystal elastic constants reveal a remarkably small discontinuity across the phase transitions even at zero temperature where the transitions are first order.
Corrosion testings of model alloys, corresponding by chemical composition to simple and complex-alloyed #gamma#- and #gamma#'-phases of nickel heat-resistant alloys are conducted in sodium sulfate and chloride melts. It is ascertained that heat resistant nickel alloys containing over 50 % of hardening #gamma#'-phase, are subject to disastrous sulfide corrosion (SC). Resistance against SC alloys containing below 50 % of #gamma#'-phase is determined by the resistance of #gamma#-solid solution. 10 refs., 3 figs., 2 tabs.
A method of using gamma radiation to determine the density and phase distribution in two-phase flows in pipes is described. Three collimated beams of radiation that pass through a pipe cross-section at different radial positions are used. A theory and computer program used to relate the measured attenuation of these beams to a three-parameter model of the phase distribution and to the average density and void fraction are discussed. Data obtained during both static and dynamic verification experiments using Lucite inserts are presented, as well as the results of several tests done in high pressure, steam-water flows.
A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, ...
We present both the theory and an experimental method to accurately set up a Guoy phase telescope, where both the output spot size and orthogonality condition are invariant to distance from the cavity beam waist. We demonstrate that Gaussian spot size measurements can be used as a diagnostic to determine the desired locations of split area photodetectors. The Guoy phase invariance is verified using the tilt-locking technique.
Purpose of the Phase I effort was to demonstrate feasibility of the fuel cell/battery system for powering a small bus (under 30 ft or 9 m) on an urban bus route. A brassboard powerplant was specified, designed, fabricated, and tested to demonstrate feasibility in the laboratory. The proof-of-concept bus, with a powerplant scaled up from the brassboard, will be demonstrated under Phase II.
The quantitative imaging of a phase object using 16 keV x-rays is reported. The theoretical basis of the techniques is presented along with its implementation using a synchrotron x-ray source. It is found that the phase image is in quantitative agreement with independent measurements of the object. 13 refs., 5 figs.
A method for the quantitative determination of atmospheric hydroperoxyl radical comprising: (a) contacting a liquid phase atmospheric sample with a chemiluminescent compound which luminesces on contact with hydroperoxyl radical; (b) determining luminescence intensity from the liquid phase atmospheric sample; and (c) comparing said luminescence intensity from the liquid phase atmospheric sample to a standard luminescence intensity for hydroperoxyl radical. An apparatus for automating the method is also included.
X-ray imaging is a very useful plasma diagnostic method. A theoretical analysis of the x-ray phase imaging in the method based on Fresnel diffraction is given. The authors show it is a linear band pass filter, a property suit for Rayleigh-Taylor (R-T) instability measurement. The evaluation permits the possibility of R-T instability measurement in x-ray phase imaging
After slow progress in the efforts to develop phase plates for electron microscopes, functional phase plate using thin carbon film has been reported recently. It permits collecting high-contrast images...Full Text Available
A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field.
A mathematical model is proposed for three-phase filtering which is a particular case of a more general model of filtering multiple component mixtures and makes it possible to describe three-phase filtering flows under conditions where the pressure of saturation is variable in time and in space. In the proposed model, the system of unknown functions is selected so that it makes it possible to trace fairly simply the pressure of saturation and to compute the corresponding equation coefficients.
According to the present invention, a joined product is at least two ceramic parts, specifically bi-element carbide parts with a bond joint therebetween, wherein the bond joint has a metal silicon phase. The bi-element carbide refers to compounds of MC, M.sub.2 C, M.sub.4 C and combinations thereof, where M is a first element and C is carbon. The metal silicon phase may be a metal silicon carbide ternary phase, or a metal silicide.
Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.
A large inguino-scrotal hernia was detected in the early phase of a radionuclide bone scan performed for evaluation of a femoral neck fracture not visualized on plain x-rays. The patient was administered 1 GBq of Scrotal scintigraphy using "9"9"mTc-MDP and a regional three-phase bone scan of the pelvis, hips and proximal femora was obtained on the gamma camera. Copyright (1999) Blackwell Science Pty Ltd
It if first shown, that the effective field of uniaxial magnetic anisotropy of Fe-Cr-P-C and Fe-Ni-B-Si system amorphous alloys is reduced with an increase of the source melt isothermal exposure time. The behaviour noted is conditioned by microcoherence and relaxation processes in the nonequilibrium liquid phase after crystal-liquid phase transition.
Heat transfer augmentation by straight grid spacers in rod bundles is studied for single phase flow and for post critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single phase flow is also examined. Governing heat transfer mechanisms are analyzed, and predictive formulations are established. For single phase flow, the local heat transfer at a straight spacer and at its upstream or downstream locations are treated separately. 18 refs.
Phased array provides many advantages over conventional ultrasonic testing method, but phased array has also limitations. This paper describes typical results of the experimental sound field analysis generated from the array probe. A photo-elastic ultrasonic visualization technique was applied in this study. The sound fields of shear wave generated from the array probe was equivalent to that from the fixed angle probe. (author)
Previous studies demonstrated that perinatal exposure to polybrominated diphenyl ethers (PBDEs), a major class of brominated flame retardants, may affect thyroid hormone (TH) concentrations by inducing...Full Text Available
The objective of the program is to develop a domestic cooktop with low NOx emissions and higher efficiency. During the first phase of the program, a developmental prototype incorporating four IR-Jet burners was assembled. The report describes the work performed during the second phase of the program and covers optimization, and testing of the developmental prototype and design, fabrication and testing of the field-test prototype.
This report presents the methodologies and results of the field/laboratory experiments and mathematical modeling defined for the phase III of the project. Results from test cases 2-6 are given in separate chapters of the report (which have been indexed separately), and the last chapter discusses the lessons learned from the three phases of the DECOVALEX project.
Several aspects of heat transfer at the annular two phase flow regime are considered. Nucleate boiling is supposed to be absent. Theoretical solutions for cases of laminar and turbulent flow in the liquid film, respectively, are considered, when steam presence does not effect the heat transfer. Heat transfer in annular flows is also considered, where steam phase consists totally or partially of the so-called incondensable gas. In this case steam phase can be a considerable resistance to heat transfer.
The accelerating flow of a lighter continuous phase through a heavier one is considered. Small nonuniformities grow into large ones due to the Rayleigh-Taylor instability. An experiment exemplifying the large bubble formation due to Rayleigh-Taylor instability was performed and simulated using the PHOENICS 84 computer code. The same numerical procedure was applied to the two-phase flow in a gun barrel. It shows that the acceleration provided by the movement of the projectile can cause initial nonuniformities to grow with time.
Cyclin-Dependent Kinase 1 (CDK1) is the major M-phase kinase known also as the M-phase Promoting Factor or MPF. Studies performed during the last decade have shown many details of how CDK1 is regulated...Full Text Available
We present in this paper the computer code BACCHUS, to analyze the thermal-hydraulics in a rod bundle in single or two-phase flow regime. The model is 2-D and uses the porous body approach. The two-phase model is an extension of the classical homogeneous model, and includes a differential non-equilibrium equation. Results are shown for the extension of the boiling region in a 19-pin bundle.
We present in this paper the computer code BACCHUS, to analyze the thermal-hydraulics in a rod bundle in single or two-phase flow regime. The model is 2-D and uses the porous body approach. The two-phase model is an extension of the classical homogeneous model, and includes a differential non-equilibrium equation. Results are shown for the extension of the boiling region in a 19-pin bundle. (orig.).
Phase-contrast imaging with a practical cone-beam X-ray tube has been realized for clinical use in digital mammography using computed radiography (CR). To perform phase-contrast imaging, the X-ray detector must be distanced from an object so that the phase-contrast image achieves magnification; in a mammography unit dedicated to phase-contrast imaging, the magnification ratio is 1.75. When using an X-ray tube with a 0.1-mm focal spot, it appears that the penumbra in magnification blurs both projected images and the phase contrast, which generates an edge effect. However, where the sampling pitch of the CR plate is 43.75 {mu}m, the blur stretches the width of the phase contrast so that unit pixels in the detector can capture it. Note that the width of an ideal phase contrast using an X-ray point source results in a phase ...
Flow-induced vibration is an important concern to the designers of heat exchangers subjected to high flows of gases or liquids. Two-phase cross-flow occurs in industrial heat exchangers, such as nuclear steam generators, condensers, and boilers, etc. Under certain flow regimes and fluid velocities, the fluid forces result in tube vibration and damage due to fretting and fatigue. Prediction of these forces requires an understanding of the flow regimes found in heat exchanger tube bundles. Excessive vibrations under normal operating conditions can lead to tube failure. Relatively little information exists on two-phase vibration. This is not surprising as single-phase flow induced vibration; a simpler topic is not yet fully understood. Vibration in two-phase is much more complex because it depends upon two-phase flow regime, i.e. characteristics of two-phase ...
Nickel-titanium alloys may coexist in more than one crystalline structure. There is a high temperature phase, austenite, and a low temperature phase, martensite. The metallurgical basis for the superelasticity and the shape memory effect relies in the ability of these alloys to transform easily from one phase to another. There are three essential factors for the orthodontist to understand nickel-titanium alloys behaviour: stress; deflection; and temperature. These three factors are related to each other by the stress-deflection, stress-temperature and deflection-temperature diagrams. This work was undertaken with the objective to analyse commercial nickel-titanium alloys for orthodontics application, using the dynamical mechanical analyser - DMA. Four NiTi 0,017 X 0,025'' archwires were studied. The archwires were Copper NiTi 35 deg C (Ormco), Neo Sentalloy F200 (GAC), Nitinol Superelastic (Unitek) and ...
The two-fluid model representation for calculations of two-phase flow characteristics in the FBR fuel pin bundles with liquid metal cooling is presented and analysed. Two conservation equations systems of the mass, momentum and energy have been written for each phase. Components accounted the mass-, momentum- and heat transfer throughout the interface occur in the macro-field equations after the averaging procedure realisation. The pattern map and correlations for two-fluid model in vertical liquid metal flows are presented. The description of processes interphase mass- and heat exchange and interphase friction is determined by the two-phase flow regime. The opportunity of the liquid metal two-phase flow regime definition is analysed. (author)
The constituent phases and associated deformed microstructure of the quenched Ti-xNb-(0.5-1.5) at.% Si alloy consisting of non-cytotoxicity elements, where x = 24-30 at.%, were investigated to provide pseudoelasticity for biomedical and sensor applications. Optical microscopy revealed that stress-induced martensitic transformation takes place during the deformation in the present alloys. It is confirmed from the X-ray diffraction results of the deformed specimens that the crystal structure of the stress-induced martensite phase is the orthorhombic so-called #alpha#'' structure. Within the alloys having #beta#(bcc) phase studied Nb-poor region appeared to exhibit a dominant behavior for stress-induced martensitic transformation than Nb-rich region. This result suggests that metastable #beta# phase is superior to stable #beta# phase for the occurrence of stress-induced martensitic ...
The thermal transformation of Al-base icosahedral phases was studied in-situ by real time neutron powder diffraction. Different compositions have been selected in order to vary the initial phase morphology and change the neutron scattering contrast between species. Alloys with low silicon and large aluminium contents produce first the orthorhombic O-Al_6Mn modification. In alloys with larger silicon content, the #alpha#-AlMnSi cubic phase appears soon after the beginning of the transformation but is still preceeded by O-Al_6Mn. Depending on compositions, the crystallization of the icosahedral phase is controlled either by the diffusion of Al through its interface with the residual fcc aluminium or that of Si within the bulk. The results are discussed in the light of current structural models. (author) 40 refs., 14 figs., 3 tabs.
Equilibrium and energy equations have been developed in describing the solid-fluid transition zone during the melting and solidification of the binary alloys. Due to the existence of the transition region exhibited both solid and fluid phases at the same material point from continuum point of view, mixture theory was utilized to analyze the region. Unlike the Stefan problem, the latent heat due to the phase change appears as a source term in the heat equation. The molten fluid is treated as a thermoviscous and incompressible fluid, whereas the solid is thermoviscoplastic described by the Bodner-Partom/Walker type of constitutive equations. Thermal mechanical behaviors of the solid and the fluid phases are determined separately because of insignificant mechanical interactions between them. Volume fractions of the phases are obtained according to the equilibrium phase diagram. The ...
Raman and infrared spectroscopy of para-H{sub 2} to pressures in excess of 200GPa and to 8K using new ultrapure synthetic diamond anvils reveals numerous new vibrational excitations in the three high-pressure phases. Highly resolved Raman-active librons indicate differences in orientational ordering between phasesII and III, including evidence for changes within phaseII. The librons in phaseIII are strongly pressure dependent and reflect a substantial increase in ordering with pressure. Multiple vibrons in all three phases (I, II, and III) are observed. The results place new bounds on predicted crystal structures and dynamics of the dense molecular solid. {copyright} {ital 1997} {ital The American Physical Society}
Magnetization, specific heat, and electrical resistivity measurements were made on single crystals of the filled skutterudite compound PrOs{sub 4}As{sub 12}. Specific heat measurements indicate an electronic specific heat coefficient {gamma} {approx} 50-200 mJ/mol K{sup 2} at temperatures 10 K {le} T {le} 18 K, and {approx} 1 J/mol K{sup 2} for t {le} 1.6 K. Magnetization, specific heat, and electrical resistivity measurements reveal the presence of two, or possibly three, ordered phases at temperatures below {approx} 2.3 K and in fields below {approx} 3 T. The low temperature phase displays antiferromagnetic characteristics, while the nature of the ordering in the other phase(s) has yet to be determined.
The automotive industry desires to optimize safety and lightweight construction for the production of cars and trucks. The resulting task for steel suppliers is to make steel grades available that can fulfil these requirements. Different projects have shown optimistic outlooks for optimization of safety and reduction of the weight of automobile bodies by using different high strength and ultra high strength steels. In the last group the dual phase steels play the lead. In recent years different steel grades have been developed and optimized for these applications. On one hand developing the mechanical properties as well as joining and forming of dual phase steels is one of the first steps. On the other hand different coated surfaces for various applications of dual phase steels is another step. Starting with characteristic production conditions for cold rolled hot dip galvanised dual phase steels, the ...
Classic and recent results for gauge effects on the properties of the normal-to-superconducting phase transition in bulk and thin film superconductors are reviewed. Similar problems in the description of other natural systems (liquid crystals, quantum field theory, early universe) are also discussed. The relatively strong gauge effects on the fluctuations of the ordering field at low spatial dimensionality D and, in particular, in thin (quasi-2D) films are considered in details. A special attention is paid to the fluctuations of the gauge field. It is shown that the mechanism in which these gauge fluctuations affect on the order of the phase transition and other phase transition properties varies with the variation of the spatial dimensionality D. The problem for the experimental confirmation of the theoretical predictions about the order of the phase transitions in gauge systems is discussed.
Phase transformations from #alpha#- to #beta#-SiAlONs (i.e., from #alpha#' to #beta#') have been recently reported in a number of rare-earth SiAlON systems during postsintering heat treatment. In the present work, this transformation process in a Sm (#alpha# + #beta#)-SiAlON material is studied by using XRD, TEM, and EDS X-ray mapping techniques. It is observed that in addition to the formation of #beta#' and M' phases, the #alpha#'-to-#beta#' transformation is accompanied by a significant increase in the amount of an AlN-polytypoid phase. The results suggest that some #alpha#' phases are thermodynamically unstable at temperatures lower than the material sintering temperature and will decompose when conditions allow. For the composition studied in this work, the #alpha#-SiAlON decomposition can be described in general as #alpha#' #-># #beta#' + M' + AlN polytypoid.
This Field Sampling Plan outlines the collection and analysis of samples in support of Phase IV of the Waste Area Group 10, Operable Units 6-05 and 10-04 remedial action. Phase IV addresses the remedial actions to areas with the potential for unexploded ordnance at the Idaho National Laboratory Site. These areas include portions of the Naval Proving Ground, the Arco High-Altitude Bombing Range, and the Twin Buttes Bombing Range. The remedial action consists of removal and disposal of ordnance by high-order detonation, followed by sampling to determine the extent, if any, of soil that might have been contaminated by the detonation activities associated with the disposal of ordnance during the Phase IV activities and explosives during the Phase II activities.
This paper explores the through-/in-plane characteristics of water transport in the cathode gas diffusion layer (GDL) of a polymer electrolyte fuel cell (PEFC). Theoretical analysis is performed on the non-isothermal two-phase flow under flow channels. A dimensionless group Da (Damkohler number for PEFC operation), defined as the ratio of water generation rate to water vapor-phase removal rate, is formulated to characterize the flow regimes in a PEFC. This group, lumping geometrical parameters and physical properties, compares the water vapor-phase removal capability (via water diffusion and holding capacity) with the rate of water production by the oxygen reduction reaction. We find that this dimensionless group can be used to characterize the non-isothermal, two-phase phenomena: when Da&...
The phase transformations and properties of a precipitation-hardened Ni-Cr-based alloy are investigated as a function of C, B, Nb, and Cr contents. It is found that the primary role of Nb consists in the formation of an independent phase, delta-Ni3Nb, a part of a gamma/gamma-prime-delta eutectoid (for high C and B concentrations) and in stimulating the gamma-sigma reaction consecutively with the gamma double prime-delta reaction (for low C and B concentrations). In both cases, the long-term strength characteristics of the Nb-alloyed system are relatively low. The substitution of boron for carbon contributes to a reduction in the number of nucleation sites for topologically close-packed phases and to the formation of more stable (with respect to excess compounds) M3B2 and MB2 borides. The high-boron material exhibits better properties and phase stability under mechanical and thermal loading. 13 ...
Experimental investigations have been conducted to determine two-phase natural circulation interfacial parameters by real-time neutron radiography. The natural circulation loop used in the present experiments consists of a vertical two-phase section, a gas liquid separator, and a gas injection/heating section. Experiments were performed in a neutron beam for visualization using realtime neutron radiography system. The natural circulation was initiated by injection of known gas flow rate in the heated section. Two-phase flow interfacial parameters including interfacial geometry and phase velocities etc. for bubbly flow and slug flow patterns observed in the experiments will be given in detail. The results indicate that while the natural circulation is largely as expected and that steady stable flows are possible, there are some local phenomena that introduce instabilities due to the interfacial phenomena ...
Experimental investigations have been conducted to determine two-phase natural circulation interfacial parameters by real-time neutron radiography. The natural circulation loop used in the present experiments consists of a vertical two-phase section, a gas liquid separator, and a gas injection/heating section. Experiments were performed in a neutron beam for visualization using realtime neutron radiography system. The natural circulation was initiated by injection of known gas flow rate in the heated section. Two-phase flow interfacial parameters including interfacial geometry and phase velocities etc. for bubbly flow and slug flow patterns observed in the experiments will be given in detail. The results indicate that while the natural circulation is largely as expected and that steady stable flows are possible, there are some local phenomena that introduce instabilities due to the interfacial phenomena ...
Analysis of the dynamics of the cavity radiation of a coherently pumped correlated emission laser is presented. The phase fluctuation and dephasing are found to affect the time evolution of the two-mode squeezing and intensity of the cavity radiation significantly. The intensity and degree of the two-mode squeezing increase at early stages of the process with time, but this trend changes rapidly afterwards. It is also shown that they increase with phase fluctuation and dephasing in the strong driving limit, however the situation appears to be opposite in the weak driving limit. This essentially suggests that the phase fluctuation and dephasing weaken the coherence induced by a strong driving mechanism so that the spontaneous emission gets a chance. The other important aspect of the phase fluctuation, in this regard, is the relaxation of the time at which the maximum squeezing is manifested as well as ...
The application of the phased array technique was limited to heavy and thick wall components as present in the nuclear industry. With the improvement of the equipment and probes other application areas are now open for the phased array technique, e.g. the inspection of the turbine blade root, weld inspection in a wall thickness range between 12 and 40 mm, inspection of aircraft components, inspection of spot welds or inspection of concretes. The aim of the use of phased array techniques has not been changed related to the first applications, i.e. the adaptation of the sound beam to the geometry by steering the angel of incidence or the skewing angle as well as the focussing of sound fields. Due to the fact, that the new applications of the phased array techniques in some cases don't leave the laboratories for the time being, the examples of this contribution will focus applications with ...
Experimental data on A-15 binary phases (the lattice parameter dependence on composition, phase diagrams, etc.) have been considered and the so-called ''compounds with A-15 structure'' are shown to be solid solutions of element substitution in the structure of A-15 type. Values of lattice parameter and atomic volume of A-15 modifications for 21 elements have been obtained (for Zr, W, Nb, Mo, V in particular). There has been shown the possibility of calculation of atomic volumes and lattice parameters of A-15 binary phases at the lack of direct experimental data. The essential role of atomic volume relations of different phases has been observed for the estimation of stability conditions of A-15 phase.
Experimental data on A-15 binary phases (the lattice parameter dependence on composition, phase diagrams, etc.) have been considered and the so-called ''compounds with A-15 structure'' are shown to be solid solutions of element substitution in the structure of A-15 type. Values of lattice parameter and atomic volume of A-15 modifications for 21 elements have been obtained (for Zr, W, Nb, Mo, V in particular). There has been shown the possibility of calculation of atomic volumes and lattice parameters of A-15 binary phases at the lack of direct experimental data. The essential role of atomic volume relations of different phases has been observed for the estimation of stability conditions of A-15 phase.
A very simple theoretical scheme is proposed to implement two- and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. In the presented protocol, the quantum information is encoded on the stable ground states of the atoms (as the controlling qubits) and the zero- and one-photon Fock states of cavity-field (as the target qubit). Under the influence of the atomic spontaneous emission, the decay of the cavity-mode, and deviation of the coupling strength, the three-qubit controlled-phase gate may have a comparatively high fidelity. The experimental feasibility of controlled-phase gate and the case that is extended to realize N-qubit controlled-phase gate are also discussed. (general)
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, ...
To compare the accuracy of MR imaging using an endorectal-pelvic and a pelvic phased-array coil for preoperative local staging of rectal carcinoma. To determine preoperative staging, 38 patients with rectal carcinoma underwent MR imaging. All patients were examined with both an endorectal-pelvic and a pelvic phased-array coil. All underwent surgery and staging was pathologically confirmed. Two radiologists blinded to pathologic stage analyzed perirectal invasion and perirectal node metastasis, and scored according to a four-point scale. Radiologic and pathologic findings were correlated. Receiver operating characteristic (ROC) analysis of Wilcoxon statistic (W values) was used to compare diagnostic accuracy between the two different MR methods. Interobserver variation was measured using {kappa} statistics. For perirectal invasion, T1WI endorectal-pelvic phased-array coil images (reader 1:0. 854, reader 2:0.818) showed ...
Characteristics of pressure drop and heat transfer have been investigated for a lithium single-phase flow and a helium-lithium two-phase flow in a horizontal conducting circular channel in the presence of a uniform transverse magnetic field up to 1.4 T as related to the lithium cooling for magnetic-confinement fusion reactors. By the application of the magnetic field to the lithium single-phase flow, remarkable heat transfer enhancement has been observed at the top wall due to the suppression of the mixed convection occurring in the low Peclet number range, while appreciable heat transfer deterioration appeared in the high Peclet number range. It has been confirmed that the helium-lithium two-phase flow can reduce the high magnetohydrodynamic (MHD) pressure drop in a lithium single-phase flow, and it can provide much better heat transfer performance than that in a helium ...
This paper describes the comprehensive modeling method of fluid and heat flows in the hydrological system. Based upon the concept that the hydrological system is composed of the air-water 2-phase fluids, and the rock phase, various natural processes are modeled including surface/subsurface 2-phase mass transfer, heat exchanges between fluid phases, between fluid and solid phases, and sensible/latent heat exchanges on the ground surface. A field-oriented numerical simulator is developed, in which a set of governing equations is solved for different variables on the surface and in subsurface regions, respectively. Results of an experimental study are presented, in which transient formulation of heat exchange between fluid/solid phases is examined through matching of the observation and calculated performances. (author)
This paper describes the comprehensive modeling method of fluid and heat flows in the hydrological system. Based upon the concept that the hydrological system is composed of the air-water 2-phase fluids, and the rock phase, various natural processes are modeled including surface/subsurface 2-phase mass transfer, heat exchanges between fluid phases, between fluid and solid phases, and sensible/latent heat exchanges on the ground surface. A field-oriented numerical simulator is developed, in which a set of governing equations is solved for different variables on the surface and in subsurface regions, respectively. Results of an experimental study are presented, in which transient formulation of heat exchange between fluid/solid phases is examined through matching of the observation and calculated performances. (author)
Iron undergoes a polymorphic phase transformation from alpha phase (bcc) to the epsilon phase (hcp) when compressed to stresses exceeding 13 CPa. Bccause the epsilon phase is denser than the alpha phase, a single shock wave is unstable and breaks up into an elastic wave, a plastic wave, and a phase transition wave. Examination of this structured wave coupled with various phase transformation models has been used to indirectly examine the transition kinetics. Recently, multimillion atom simulations (molecular dynamics) have been used to examine the shock-induced transition in single crystal iron illustrating an orientation dependence of the transition stress, mechanisms, and kinetics. The objective of the current work was to perform plate impact experiments to examine the shock-response of polycrystalline and single crystal iron with ...
This study explores a method to characterize temporal structure of intermittent phase locking in oscillatory systems. When an oscillatory system is in a weakly synchronized regime away from a synchronization threshold, it spends most of the time in parts of its phase space away from synchronization state. Therefore characteristics of dynamics near this state (such as its stability properties/Lyapunov exponents or distributions of the durations of synchronized episodes) do not describe system's dynamics for most of the time. We consider an approach to characterize the system dynamics in this case, by exploring the relationship between the phases on each cycle of oscillations. If some overall level of phase locking is present, one can quantify when and for how long phase locking is lost, and how the system returns back to the phase-locked state. We consider ...
The effect of the nitrogen uptake in {alpha}-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic {alpha}-Fe phase (50%). The 20% of specimen volume form {alpha}'-Fe and {alpha}''-Fe{sub 16}N{sub 2} phases. The last 30% occupy the {gamma}'-Fe{sub 4}N, ferro- and paramagnetic {epsilon} phases, and {gamma}-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into {alpha}-iron particles which results in the formation of paramagnetic {epsilon}({zeta})-Fe{sub 2}N ...
The effect of the nitrogen uptake in #alpha#-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic #alpha#-Fe phase (50%). The 20% of specimen volume form #alpha#'-Fe and #alpha#''-Fe_1_6N_2 phases. The last 30% occupy the #gamma#'-Fe_4N, ferro- and paramagnetic #epsilon# phases, and #gamma#-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into #alpha#-iron particles which results in the formation of paramagnetic #epsilon#(#zeta#)-Fe_2N phase. This ...
Aluminum-containing intergranular phases, forming intergranular films and secondary phase particles at triple-junctions in SiC hot-pressed with aluminum, boron, and carbon additions, were studied by transmission electron microscopy. Statistical high-resolution electron microscopy study of intergranular films indicated that a large fraction of the vitreous intergranular films in the s-hot-pressed SiC crystallized during postannealing in argon above 1000 C. However, brief heating to 1900 C indeed re-melted 25 percent of the crystallized intergranular films. The structural transitions were reflected in the statistical width distributions of the amorphous grain boundary layers. At triple-junctions, Al2O3, Al2OC-SiC solid solution, and mullite phases were newly identified. These phases,together with others reported before are represented in a quaternary phase diagram for 1900 C. It is ...
Triclinic b-BiNbO4 prepared below 750^oC and above 1040^oC (denoted as Low-b and High-b, respectively) and pure orthorhombic a-BiNbO4 at 900^oC were successfully derived from a citrate method and the phase transition from b-BiNbO4 to a-BiNbO4 was first observed in BiNbO4 powders. This phenomenon proves that the abnormal phase transition from b-BiNbO4 to a-BiNbO4 exists in BiNbO4 powder system. The synthesis of Low-b powders can be attributed to the formation of the intermediate phase of Bi5Nb3O15 by the citrate method. With increasing temperature, the Low-b phase gradually turns into a-BiNbO4 due to the thermodynamically metastable state of Low-b. We also identified that the stress in pellet format can accelerate the phase transition from Low-b to a phase of BiNbO4 in comparison with powde...
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 ...
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 ...
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 ...
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 materials investigated, the ...
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.)
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).
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)
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.
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.