[en] The limiting conditions relating to successful combined injection cooling of reactor coolant channels are investigated. These conditions relate to the use in Emergency-Core-Cooling Systems of simultaneous top and bottom injected cooling water. Use is made of a 9-rod, full-length, electrically heated assembly for the experimental studies. Limiting combined injection conditions for this assembly have been determined for an equivalent rod linear heating rate of 0.4 Kw per ft with an initial temperature of about 900⁰F. A slug flow analytical model is derived to describe the pressure drop experienced for the observed flooding type of phenomena. The model is used to predict the observed pressure drop response with partial success, however, improvement is indicated by incorporating condensation effects

[en] This thesis presents experiments for the production of ultracold rubidium cesium mixture in a magnetic trap. The long-termed aim of the experiment is the study of the interaction of few cesium atoms with a Bose-Einstein condensate of rubidium atoms. Especially by controlled variation of the cesium atom number the transition in the description of the interaction by concepts of the one-particle physics to the description by concepts of the many-particle physics shall be studied. The rubidium atoms are trapped in a magneto-optical trap (MOT) and from there reloaded into a magnetic trap. In this the rubidium atoms are stored in the state vertical stroke f=2,m_f=2 right angle of the electronic ground state and evaporatively cooled by means of microwave-induced transitions into the state vertical stroke f=1,m_f=1] (microwave cooling). The cesium atoms are also trppaed in a MOT and into the same magnetic trap reloaded, in which they are stored in the state vertical stroke f=4,m_f=4 right angle of the electronic ground state together with rubidium. Because of the different hyperfine splitting only rubidium is evaporatively cooled, while cesium is cooled jointly sympathetically - i.e. by theramal contact via elastic collisions with rubidium atoms. The first two chapters contain a description of interatomic interactions in ultracold gases as well as a short summary of theoretical concepts in the description of Bose-Einstein condensates. The chapters 3 and 4 contain a short presentation of the methods applied in the experiment for the production of ultracold gases as well as the experimental arrangement; especially in the framework of this thesis a new coil system has been designed, which offers in view of future experiments additionally optical access for an optical trap. Additionally the fourth chapter contains an extensive description of the experimental cycle, which is applied in order to store rubidium and cesium atoms together into the magnetic trap. The last chapter finally contains the experimental results as well as the analysis of which. In experiments, which involve only rubidium, rubidium is coolde by means of microwave cooling; thereby an unwanted population of the state vertical stroke f=2,m_f=1 right angle is observed, which hinders the condensation. The population of the state vertical stroke f=2,m_f=1 right angle is systematically studied. The continuous depopulation of the state vertical stroke 2,1 right angle by means of a second microwave frequency radiated upon allows the production of rubidium condensates of 10⁵ atoms after 23 s evaporative cooling. By selective microwave cooling of the rubidium atoms the rubidium cesium mixtures are cooled until 700 mK. By means of a simple model the sympathetic cooling of cesium is analyzed, which allows a first characterization of the rubidium-cesium interaction

[en] Recent dramatic changes in natural gas markets have significant implications for the scope and direction of DOE's upstream as well as downstream natural gas R ampersand D. Open access transportation changes the way gas is bought and sold. The end of the gas deliverability surplus requires increased reserve development above recent levels. Increased gas demand for power generation and other new uses changes the overall demand picture in terms of volumes, locations and seasonality. DOE's Natural Gas Strategic Plan requires that its R ampersand D activities be evaluated for their ability to provide adequate supplies of reasonably priced gas. Potential R ampersand D projects are to be evaluated using a full fuel cycle, benefit-cost approach to estimate likely market impact as well as technical success. To assure R ampersand D projects are evaluated on a comparable basis, METC has undertaken the development of a comprehensive natural gas technology evaluation framework. Existing energy systems models lack the level of detail required to estimate the impact of specific upstream natural gas technologies across the known range of geological settings and likely market conditions. Gas Systems Analysis Model (GSAM) research during FY 1993 developed and implemented this comprehensive, consistent natural gas system evaluation framework. Rather than a isolated research activity, however, GSAM represents the integration of many prior and ongoing natural gas research efforts. When complete, it will incorporate the most current resource base description, reservoir modeling, technology characterization and other geologic and engineering aspects developed through recent METC and industry gas R ampersand D programs

[en] Most x-irradiation-induced thymomas in C57BL/6 mice are virus-free when assayed by immunofluorescence for the gs antigen (gsa) of murine leukemia virus (MuLV). Virus was induced transiently in bone marrow cells and later appeared in thymus cells. Six to 7 weeks post irradiation, thymocytes and bone marrow cells were MuLV gsa-negative and remained negative for the lifetime of most animals, whether or not they contracted overt leukemia. During the period when MuLV gsa-positive bone marrow cells were found, XC-positive syncytia-producing bone marrow cells were also found. Virus information was expressed, therefore, for a limited duration, long before any signs of leukemia in the animal were evident. MuLV gsa-positive thymocytes taken from mice 4 weeks after x-irradiation were cocultivated with a series of indicator cells. B-tropic virus, in addition to a xenotropic virus, was isolated from these cells. Ecotropic virus was not found in normal mouse thymocytes, in irradiated thymocytes a few days after termination of the X-irradiation sequence, or in most primary thymomas. All thymocytes produced only xenotropic virus in the cocultivation assays. Expression of the ecotropic virus was, therefore, transient, as assayed by immunofluorescence, XC syncytia formation, and virus isolation from MuLV gsa-positive thymus cells

[en] (Na + K + Cl) cotransport is the major mechanism of salt transport across the apical membrane of the epithelial cells of the thick ascending limb of Henle's loop of mammalian kidney and the site of action of loop diuretics such as furosemide and bumetanide. We have identified a 150-kDa protein in membranes from dog kidney cortex that is photolabeled by a radiolabeled, benzophenone analogue of bumetanide, [³H]4-benzoyl-5-sulfamoyl-3-(3-thenyloxy)benzoic acid ([³H]BSTBA). Several pieces of evidence strongly suggest that this 150-kDa protein is at least part of the (Na + K + Cl) cotransport system. 1) Photoincorporation of [³H]BSTBA into this protein is completely blocked by inclusion of 10 microM unlabeled bumetanide in the photolysis medium. 2) Photoincorporation of [³H]BSTBA into this protein shows a saturable dependence on [³H]BSTBA concentration, with a K 1/2 (approximately 0.1 microM) very similar to that for reversible [³H]BSTBA binding to kidney membranes. 3) Photolabeling of this protein by [³H]BSTBA requires the simultaneous presence of Na, K, and Cl in the photolysis medium. 4) When crude membranes from dog kidney cortex are centrifuged on sucrose density gradients, saturable [³H]bumetanide binding and photoincorporation of [³H]BSTBA in the 150-kDa region show a very similar distribution among the 15 gradient fractions collected. [³H]BSTBA is also photoincorporated into at least two lower molecular mass proteins, the largest of which is approximately 50 kDa

[en] Unique type-specific antigens were detected on cells infected with dualtropic and thymotropic viruses and x-ray-induced T cell- and B cell-malignant lymphomas of C57BL/6 mice. These findings support the contention that T cell lymphoma (TCL)-inducing and B cell lymphoma (BCL)-indcing viruses isolated from x-irradiated C57BL/6 mice are env gene recombinants in which ecotropic gene sequences have been substituted by xenotropic sequences. We found that unique antigenicities are associated with each TCL-inducing and BCL-inducing dualtropic virus, and that the thymotropic TCL-inducing virus isolates represent a separate serologic group. These virus mapping experiments indicated that many serologically different recombinant viruses can be isolated from C57BL/6 mice. It is suggested that many distinct recombinant viruses may exist in lymphomagenic C57BL/6 mice, some of which are associated with specific lyphoma induction

[en] An expression for the amplitude of a pulse of synchrotron radiation coherently scattered in the forward direction by a Moessbauer absorber consisting of randomly oriented paramagnetic iron-containing molecules (for example, a frozen solution of a ⁵⁷Fe protein) in an applied magnetic field is derived from the theory of γ optics. It is assumed that the hyperfine splittings present in the Moessbauer nuclei can be described in the framework of the spin-Hamiltonian formalism. In the general case of a thick Moessbauer sample of this kind the response on an incident monochromatic and fully polarized beam cannot be given analytically because of the integrations involved. How nuclear forward-scattering for this general case is evaluated in the program package called SYNFOS is outlined

[en] Polariton effects are considered in the case of one-phonon scattering of Moessbauer radiation in a resonant medium. It is shown that the polariton renormalization of group velocity of the initial and the scattered beam causes a gap in the spectrum of coherently scattered radiation. Such gap is centered at the resonant frequency ω_r, and its width and shape depend on the acoustical properties of the scatterer. The properties of the vibrational modes, active in one-phonon coherent processes, and some aspects of the experimental investigation of the gap are also discussed. (author)

No abstract available

[en] 4-benzoyl-5-sulfamoyl-3-(3-thenyloxy) benzoic acid (BSTBA) is an effective loop diuretic, and a potential photoaffinity reagent for the Na,K,Cl co-transport system because of its benzophonone structure. The authors find that BSTBA blocks ³H bumetanide binding to membranes from dog kidney outer medulla with affinity < 100 nM. When kidney membranes are incubated with ³H-BSTBA (prepared by catalytic exchange, purified by HPLC) and exposed to long wave ultraviolet light, radiolabel is incorporated into a ∼170K dalton protein. The labeled SDS gel band corresponds to a band which, on reexamination of unpublished gels, is seen to be enriched by sucrose gradient centrifugation in parallel with ³H-bumetanide binding. Both binding and covalent incorporation of ³H-BSTBA require the simultaneous presence of Na,K, and CL, are half maximal below 100 nM ³H-BSTBA, and are completely blocked by 10 μM bumetanide. In contrast, the authors find that photolabeling of a 35K dalton band by ³H-bumetanide is not completely prevented by 50 μM unlabeled bumentanide, suggesting that this low molecular weight protein may not be part of a transport system with high bumetanide affinity. These results provide strong evidence that the 170K dalton protein is at least part of the bumetanide sensitive Na,K,Cl-cotransport system