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[en] Radioactive tracers are of considerable importance in investigations for gaining information on the essential features of the flow in industrial process vessels. The technique, in which tracer is added momentarily to the inlet of the system and the resulting concentration-vs. -time relationship is recorded at the outlet, has been experimentally well established and yields information in terms of mean residence time, dispersion, etc. In systems with recirculation, where some of the tracer after having been recorded at the outlet is again fed back to the inlet, a simple evaluation of the concentration-vs- -time curve is not possible since the contributions from the recycling tracer cannot, as a rule, be separated from the curve representing the first passage of tracer. Assuming that only part of the tracer is fed back on each return and that the system is in steady-stale operation, a simple set of relationships have been derived which permit calculation of the recirculating fraction of the flow as well as of the mean and variance of the residence-time distribution corresponding to a momentary addition of tracer at the inlet (i.e. the transfer function of the system) from parameters taken from the composite concentration curve recorded at the exit. The methods developed have been applied in the evaluation of a number of tracer investigations on liquor flow through the chip bed in a continuous digester for pulp making. A complete analysis of the experimental data could be made to give consistent results. (author)
[en] The problem that still arises in lung scintigraphy as a result of the discrepancies between scan interpretations and clinical observations are described. On the basis of data obtained from 500 cases of common and rare lung diseases it was found that different groups of diseases can produce similar or identical scintigrams. However, because of the wide range of variation it was not possible to work out a typical distribution pattern. After discussing significant examples, reference is made to the special case of scintigrams which represent two or more diseases. It is suggested that patho-physiological factors may provide a possible explanation of the similar scans from cases with a different clinical origin. In addition, as a more positive feature, a comparison is made with the results of other lung examinations or scintigraphic checks carried out during the course of a disease; this made it possible to introduce differential-diagnostic considerations in discussion with the clinicians and to derive more information from the scans. (author)
[en] Elements present as impurity in uranium matrix were analysed using spectrophotometric technique. The elements chosen represent the following group: I-Cu; II-Cd; VI-Cr; Mo and Mn; VII-Fe, Co and Ni, Boron, although a member of group III, does not really represent this group because of its properties closer to group II. Due to the difficulties it causes in analysis, it is considered to belong to group III. Therefore, the analytical results of boron were found to be more scattered than any other element. 1 ref., 11 tabs
[en] Following comparisons of oven-dried, air-dried and freeze-dried plant material used for autoradiography, a freeze-drying method is described. A review is made of the equipment used and a detailed description of a freeze drier is given. A simple process from frozen dry plant material to autoradiogram with a high resolution, even in the case of high-energy elements, is considered. (author)
[en] A theoretical basis for radioimmunoassay as a special case of competitive radioassay is presented. Special consideration is given to practical problems including methods for separation of free and bound hormone, production and selection of antisera, preparation and protection against damage of suitable labelled antigens and evaluation of the specificity of the assay. (author)
[en] Methods to determine molybdenum in uranium-molybdenum alloys are developed by various technic: molecular absorption spectrophotometry, emission spectroscopy, X ray fluorescence, atomic absorption spectrophotometry. After a comparison on samples in which molybdenum content lies between 1 and 10 per cent by weight, one concludes in the interest of some of the exposed methods for routine analysis. (author)
[fr]On expose plusieurs methodes de dosage du molybdene dans les alliages uranium-molybdene par des techniques aussi diverses que: spectrophotometrie d'absorption moleculaire, spectrographie d'emission, fluorescence de rayons X, spectrophotometrie d'absorption atomique. Apres une comparaison portant sur des echantillons dont les teneurs en molybdene sont comprises entre 1 et 10 pour cent en poids, on conclut a l'interet de l'emploi de certaines des methodes exposees pour des analyses de serie. (auteur)
[en] The papers of this session are very heterogeneous, so it is difficult to group them in any logical order. In general, they treat MHD generators or channels using simplifying models to reduce the complexity of the general problem. They cannot easily be compared, since the simplifying assumptions made for the models are different. Therefore, I shall treat each of the papers I am considering (SM-74/1, 13, 49, 52, 55, 98, 99, 110, 139, and 254) separately.
[en] Repeated measurement of cardiac output in the same 11 normal individuals were done with 131I-Hippuran and RIHSA. Following results were obtained. 1) The cardiac output measured with RIHSA was 6750±866 ml/min. 2) The cardiac output measured with 131I-Hippuran was 5940±764 ml/min. 3) The relative value of cardiac output measured with 131I-Hippuran to that measured with RIHSA was 88 percent, and a statistical significance was found present in the difference.
[en] For the application of physicochemical values to practical and theoretical problems, it becomes increasingly important that the published experimental data should continuously be sifted and critically assessed by experts. This type of work is actually a relatively new field in chemistry, and some of the principles and methods involved in assessing the thermodynamic and transport properties of metallic substances will be discussed. The centres dealing with this evaluation work, their distribution and their accepted responsibilities will be outlined. (author)
[fr]Pour pouvoir appliquer les valeurs physico-chimiques à l'étude de problèmes théoriques et pratiques, il importe de plus en plus que les valeurs expérimentales publiées soient continuellement passées au crible par les spécialistes. Ce genre de travail constitue en fait un domaine relativement nouveau de la chimie. L'auteur examine certains des principes et méthodes qui interviennent dans l'évaluation des propriétés thermodynamiques et des propriétés de transport de diverses substances métalliques. Il indique les centres chargés de ces évaluations, leur répartition et leurs responsabilités respectives. (author)
[es]Para poder aplicar los valores fisicoqufmicos a problemas teóricos y prácticos, es indispensable que los expertos procedan a evaluaciones continuas y críticas de los datos experimentales publicados. Este tipo de trabajo constituye un campo relativamente nuevo de la química; el autor analiza en la memoria algunos de los principios y métodos aplicados en la evaluación de las propiedades termodinámicas y de transporte de las sustancias metálicas. La memoria describe los centros dedicados a este trabajo de evaluación, su distribución y las responsabilidades pertinentes. (author)
[ru]Vse bol'shee znachenie dlja ispol'zovanija fiziko-himicheskih svojstv veshhestv dlja reshenija prakticheskih i teoreticheskih problem priobretaet analiz i kriticheskaja ocenka jekspertami publikuemyh jeksperimental'nyh dannyh. Jetot vid raboty javljaetsja po sushhestvu novoj oblast'ju v himii, i nekotorye principy i metody ocenki termodinamicheskih svojstv metallicheskih veshhestv i ih svojstv po perenosu budut obsuzhdeny. Daetsja kratkoe opisanie centrov, zanimajushhihsja jetoj rabotoj, ih mestonahozhdenija i vypolnjaemyh zadach. (author)