Thermohydraulics in a high temperature gas-cooled reactor prestressed concrete reactor vessel during unrestricted core heatup accidents

The long term core and primary loop heatup of an HTGR subsequent to loss of all forced circulation has been analyzed using a modified version of the CORCON code. The results indicate that if the liner cooling system is operating, or can be restarted within about 60 h, safe cooldown can be achieved, but significant core damage will occur. Without functioning liner cooling system the core heatup will lead to PCRV concrete degradation and the resulting concrete gas releases will ultimately cause containment building failure after 6 to 10 days.     

Pseudoelastic deformation and size effects during in situ transmission electron microscopy tensile testing of NiTi

The stress-induced B2–B19′ transformation in aged 51 at.% NiTi was investigated using in situ straining transmission electron microscopy (TEM). Increased applied strain along [1 1 0]_B2 transforms B2 into plates containing B19′ variants that are related by a (1 1 0)_B2 compound twin plane. This atypical twin plane is explained by relaxing the invariant plane constraint in the crystallographic theory of martensite (CTM) to an invariant line constraint. The relaxation is rationalized from the thin foil geometry. The relaxed CTM approach, coupled with conditions to maximize transformation strain along the loading axis and minimize elastic energy, predicts the observed twin interface, diffraction patterns, and interface with the B2 austenite. These results demonstrate subtleties in interpreting thin foil TEM results regarding martensitic transformations, and translating those results to bulk response.     

Prognostic Impact of Membranous/Nuclear Epidermal Growth Factor Receptor Localization in Clear Cell Renal Cell Carcinoma

EGFR is overexpressed in the majority of clear cell renal cell carcinomas (CCRCCs). Although EGFR deregulation was found to be of great significance in CCRCC biology, the EGFR overexpression is not associated with EGFR-targeted therapy responsiveness. Moreover, the prognostic role of EGFR expression remains controversial. In the present study, we evaluated the role played by EGFR overexpression in CCRCC and its prognostic significance associated with different immunohistochemical localization patterns. In our study, the Total Score (TS) related to membranous-cytoplasmic EGFR expression showed a significant correlation with grade, pathologic stage (pT), and Stage, Size, Grade, and Necrosis (SSIGN) score, and a negative correlation with nuclear EGFR expression. No significant correlations were shown between nuclear EGFR and clinic-pathological features. Additionally, a correlation between SGLT1 expression levels and pT was described. Multivariate analysis identifies pT and SSIGN score as independent prognostic factors for CCRCC. A significantly increased survival rate was found in the case of positive expression of nuclear EGFR and SGLT1. Based on our findings, SGLT1 and nuclear EGFR overexpression defines a subgroup of CCRCC patients with good prognosis. Membranous-cytoplasmic EGFR expression was shown to be a poor prognostic factor and could define a CCRCC subgroup with poor prognosis that should be responsive to anti-EGFR therapies.     

Energy sector assistance in developing countries: Current trends and policy recommendations

An estimated 2.5 billion people remain without access to modern energy supplies. This shortfall is expected to grow as the population in developing countries continues to grow rapidly and the existing infrastructure ages. The United Nations’ goal of lowering poverty by half by 2015 will not be attained unless the poor in developing countries gain greater access to basic infrastructure and services, including energy services. The key objective of this paper is to analyze trends in overseas development assistance (ODA) to the energy sector in developing countries during the period 1990–2003, relative to realized private sector investments. This analysis then forms the basis for policy recommendations for consideration by decision makers within countries that are major contributors to ODA.     

Bending of flux lines by transport currents in type II superconductors measured by neutron diffraction

Neutron diffraction experiments have been performed on three Nb-13% Ta specimens in order to obtain information about the distribution of transport currents in type II superconductors. For sample one, which had the lowest pinning strength, it was concluded that most of the transport current was carried in a region near the surface. However, in sample two, in which the flux pinning was homogeneous, as indicated by ac flux penetration measurements, and in sample three, in which the pinning strength was highest, it was clearly demonstrated that a transport current was carried in the bulk and the experimental results could be explained by specific predictions of the critical state model.Guest scientist from Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, operated by the Energy Research and Development Administration under contract with Union Carbide Corporation.     

Depletion voltage and charge collection for highly irradiatedsilicon microstrip detectors with various initial resistivities

We have irradiated p-on-n silicon microstrip detectors of initial bulk resistivity between 0.2 and 2.7 kΩ-cm with 55 MeV protons to fluences of 0.7, 2 and 11×10¹³ p/cm² (equivalent to twice the fluence in high energy protons), and have measured the depletion voltage before and after irradiation using C-V methods. In addition, we have measured the charge collection of minimum ionization on a single strip with a fast amplifier as a function of bias voltage. We compare the depletion voltage deduced from both methods for samples with different initial resistivities     

A new process with a potential to rapidly texture bulk YBa2Cu3Ox superconductor

A new process has been developed to texture bulk YBa₂Cu₃O_x superconductors at temperatures about 100°C below the peritectic temperature. The texture is achieved in this process by directional recrystallization of compacts fabricated from quenched YBCO powders. Isothermal recrystallization of quenched precursors at 890°C for 3 min is found to result in the formation of more than 75% of YBa₂Cu₃O_x phase without any Y₂BaCuO₅. Recrystallization at higher temperatures leads to rapid formation of fine Y₂BaCuO₅ precipitates in addition to YBa₂Cu₃O_x. The formation of YBa₂Cu₃O_x increases with increasing heating rates. Directional recrystallization at 10 mm/h results in a well-textured microstructure with the YBa₂Cu₃Ox grains oriented parallel to the sample length. The magnetic field dependence of the critical current density at 77K of the directionally recrystallized material compares well with that of melt-textured YBCO and is superior to that of magnetically aligned and sintered YBCO.