Wafer-level MOCVD growth of AlGaN/GaN-on-Si HEMT structures with ultra-high room temperature 2DEG mobility

Directory of Open Access Journals (Sweden)

Xiaoqing Xu

2016-11-01

Full Text Available In this work, we investigate the influence of growth temperature, impurity concentration, and metal contact structure on the uniformity and two-dimensional electron gas (2DEG properties of AlGaN/GaN high electron mobility transistor (HEMT structure grown by metal-organic chemical vapor deposition (MOCVD on 4-inch Si substrate. High uniformity of 2DEG mobility (standard deviation down to 0.72% across the radius of the 4-inch wafer has been achieved, and 2DEG mobility up to 1740.3 cm2/V⋅s at room temperature has been realized at low C and O impurity concentrations due to reduced ionized impurity scattering. The 2DEG mobility is further enhanced to 2161.4 cm2/V⋅s which is comparable to the highest value reported to date when the contact structure is switched from a square to a cross pattern due to reduced piezoelectric scattering at lower residual strain. This work provides constructive insights and promising results to the field of wafer-scale fabrication of AlGaN/GaN HEMT on Si.

Fisica degli atomi e dei nuclei

CERN Document Server

Bernardini, Carlo

1965-01-01

Evidenza della struttura atomica della materia ; le proprietà degli atomi e la meccanica atomica ; gli atomi e le radiazioni elettromagnetiche ; struttura microscopica dello stato gassoso ; struttura microscopica dello stato liquido ; struttura microscopica della stato solido ; proprietà elettriche e magnetiche delle sostanze ; proprietà dei nuclei degli atomi ; le particelle elementari.

Behavior of ferritic/martensitic steels after n-irradiation at 200 and 300 deg. C

International Nuclear Information System (INIS)

Matijasevic, M.; Lucon, E.; Almazouzi, A.

2008-01-01

High chromium ferritic/martensitic (F/M) steels are considered as the most promising structural materials for accelerator driven systems (ADS). One drawback that needs to be quantified is the significant hardening and embrittlement caused by neutron irradiation at low temperatures with production of spallation elements. In this paper irradiation effects on the mechanical properties of F/M steels have been studied and comparisons are provided between two ferritic/martensitic steels, namely T91 and EUROFER97. Both materials have been irradiated in the BR2 reactor of SCK-CEN/Mol at 300 deg. C up to doses ranging from 0.06 to 1.5 dpa. Tensile tests results obtained between -160 deg. C and 300 deg. C clearly show irradiation hardening (increase of yield and ultimate tensile strengths), as well as reduction of uniform and total elongation. Irradiation effects for EUROFER97 starting from 0.6 dpa are more pronounced compared to T91, showing a significant decrease in work hardening. The results are compared to our latest data that were obtained within a previous program (SPIRE), where T91 had also been irradiated in BR2 at 200 deg. C (up to 2.6 dpa), and tested between -170 deg. C and 300 deg. C. Irradiation effects at lower irradiation temperatures are more significant

Nitrogen implantation into silicon at 700-1100 deg C

International Nuclear Information System (INIS)

Kachurin, G.A.; Tyschenko, I.E.; Popov, V.P.; Tijs, S.A.; Plotnikov, A.E.

1989-01-01

Nitrogen ions 130-140 kW potential accelerated were implanted in silicon heated up to Ti=700-1100 deg C. Densities of ion current were 1-5 mcA/cm 2 , doses did not exceed 5x10 17 cm -2 . Initial stages of nitride formation in buried layers are investigated by means of Rutherford backscattering, layer-by-layer Augerspctroscopy and electron microscopy. It is determind, that Ti growth from 700 up to 900 deg C is accompanied by essential reduction of defectiveness of silicon near-the-surface layer at nitrogen retention within the limits of the calculation profile of ion ranges. At Ti=900 deg C nitrogen is rather mobile and at ∼5x10 16 cm -2 dose it is drown to α-Si 3 N 4 crystalling extraction in R p range. Beginning from Ti ≅1000 deg C nitrogen is not retained in the furied layer and diffuses to the surface. No essenstial losses of nitrogen due to evaporation or inside diffusion are observed. It is noted, that critical Ti, when nitrogen is accumulated in the buried layer, correspond to critical temperatures, when light ions introduce essential structure distortions. Conclusion is made, that irradition-introduced distortions of structure represent centres of initiation and growth of nitride phase. At 1150 deg C additional annaling during 3 hs nitrogen, occurring outside the stable extraction, is redistributed between th surface and furied layers, sintering in narrow concentration peaks

Experimental alteration of R7T7 glass in salt brines at 90 deg C and 150 deg C

International Nuclear Information System (INIS)

Godon, N.; Vernaz, E.; Gin, S.; Beaufort, D.; Thomassin, J.H.

1991-01-01

Static experiments have been developed to investigate the R7T7 glass corrosion in four natural salt brines (brines 1 and 3: pure halite, brines 2 and 4: high Mg, K fluid inclusions rich halite), at 90 deg C and 150 deg C with 0.7 cm -1 S/V ratio and at 11 different running times. Analysis of brines after alteration (pHmeter and ICP) added to a detailed study of the crystalline phases developed at the interface glass-brine (XRD,SEM and Microprobe), showed that the influence of the compositional difference is more important on the nature of the secondary phases formed than on the corrosion rate of the glass. After 91 days of alteration at 150 deg C stady states to be reached (after 40 days at 90 deg C). A long term experiment (1 year) is necessary to confirm this hypothesis. 7 refs., 7 figs., 2 tabs

A new method to determine the 2DEG density distribution for passivated AlGaN/AlN/GaN heterostructure field-effect transistors

Science.gov (United States)

Fu, Chen; Lin, Zhaojun; Cui, Peng; Lv, Yuanjie; Zhou, Yang; Dai, Gang; Luan, Chongbiao; Liu, Huan; Cheng, Aijie

2018-01-01

A new method to determine the two-dimensional electron gas (2DEG) density distribution of the AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) after the Si3N4 passivation process has been presented. Detailed device characteristics were investigated and better transport properties have been observed for the passivated devices. The strain variation and the influence of the surface trapping states were analyzed. By using the polarization Coulomb field (PCF) scattering theory, the 2DEG density after passivation was both quantitively and qualitatively determined, which has been increased by 45% under the access regions and decreased by 2% under the gate region.

Global map of lithosphere thermal thickness on a 1 deg x 1 deg grid - digitally available

Science.gov (United States)

Artemieva, Irina

2014-05-01

This presentation reports a 1 deg ×1 deg global thermal model for the continental lithosphere (TC1). The model is digitally available from the author's web-site: www.lithosphere.info. Geotherms for continental terranes of different ages (early Archean to present) are constrained by reliable data on borehole heat flow measurements (Artemieva and Mooney, 2001), checked with the original publications for data quality, and corrected for paleo-temperature effects where needed. These data are supplemented by cratonic geotherms based on xenolith data. Since heat flow measurements cover not more than half of the continents, the remaining areas (ca. 60% of the continents) are filled by the statistical numbers derived from the thermal model constrained by borehole data. Continental geotherms are statistically analyzed as a function of age and are used to estimate lithospheric temperatures in continental regions with no or low quality heat flow data. This analysis requires knowledge of lithosphere age globally. A compilation of tectono-thermal ages of lithospheric terranes on a 1 deg × 1 deg grid forms the basis for the statistical analysis. It shows that, statistically, lithospheric thermal thickness z (in km) depends on tectono-thermal age t (in Ma) as: z=0.04t+93.6. This relationship formed the basis for a global thermal model of the continental lithosphere (TC1). Statistical analysis of continental geotherms also reveals that this relationship holds for the Archean cratons in general, but not in detail. Particularly, thick (more than 250 km) lithosphere is restricted solely to young Archean terranes (3.0-2.6 Ga), while in old Archean cratons (3.6-3.0 Ga) lithospheric roots do not extend deeper than 200-220 km. The TC1 model is presented by a set of maps, which show significant thermal heterogeneity within continental upper mantle. The strongest lateral temperature variations (as large as 800 deg C) are typical of the shallow mantle (depth less than 100 km). A map of the

Neutron damage of silicon detectors at 20 deg C

International Nuclear Information System (INIS)

Bardos, R.; Gorfine, G.; Guy, L.; Moorhead, G.; Taylor, G.; Tovey, S.

1992-01-01

This contribution reports new data on the damage of silicon detectors by low energy (1 MeV) neutrons. The data were taken at the end of 1991. Three exposures of UA2 Inner Silicon detectors were made: at +20 deg C, -15 deg C and -95 deg C. A high neutron flux enabled the required fluences to be achieved in relatively short times. This increases the sensitivity of the experiment to damage types with shorter self-annealing time constants. This note discusses the new data taken at +20 deg C. Analysis of the low temperature exposures is in progress. 5 refs., 15 figs

Microcalorimetric studies on lithium thionyl chloride cells: temperature effects between 25deg C and -40deg C

Energy Technology Data Exchange (ETDEWEB)

Hill, I.R.; Sibbald, A.M.; Donepudi, V.S.; Adams, W.A. (Ottawa Univ., ON (Canada). Electrochemical Science and Technology Centre); Donaldson, G.J. (Dept. of National Defence, Ottawa, ON (Canada))

1992-06-01

Microcalorimetry studies were performed on commercial lithium/thionyl chloride cells to investigate whether there was a change in reaction mechanisms in the temperature range between 25deg C and -40deg C. The entropy change associated with cell discharge was calculated from the calorimetry data and was also determined from the temperature dependence of the open-circuit potential. The entropy changes determined by the two methods are compared and discussed in terms of the electrolyte composition variable. (orig.).

Creep constitutive equations for a 0.5Cr 0.5 Mo 0.25V ferritic steel in the temperature range 565 deg. C-675 deg. C

International Nuclear Information System (INIS)

Mustata, R.; Hayhurst, D.R.

2005-01-01

A two damage state variable model is used to describe the softening mechanisms, damage initiation and growth for a low alloy ferritic steel 1/2Cr-1/2Mo-1/4V at 565 and 590 deg. C within the Continuum Damage Mechanics framework. The level of complexity of the constitutive equations and the degree of coupling through damage is high and it is difficult to calibrate values of the constitutive constants without recourse to optimisation techniques. A methodology for the analysis of uni-axial experimental data, coupled with a traditional gradient-based optimisation technique, is presented for the unique determination of the constitutive constants. Two sets of experimental data on parent material are used for inversion purposes: at 565 deg. C, c.f. Cane [Cane BJ. Collaborative programme on the corelation of test data for high temperature design of welded steam pipes. Presentation and analysis of the material data. Note No. RD/L/2101N81, March, CEGB Laboratory; 1981]; and, at 590 deg. C, c.f. Miller [Miller DA. Private communication: 'Creep rupture testing of Cr M V pipe steel. ERA Project 63-01-040320009'. Barnwood, Gloucs, UK: British Energy; 2000]. The variation of the constitutive parameters with temperature in the range 565-590 deg. C has been deduced by considering the values of constitutive parameters for the same alloy deduced by Perrin and Hayhurst [Perrin IJ, Hayhurst DR. Creep constitutive equations for a 0.5Cr-0.5Mo-0.25V ferritic steel in the temperature range 600-675 deg. C. J Strain Anal 1996;31:299-314] in the temperature range 620-675 deg. C

Low Temperature (320 deg C and 340 deg C) Creep Crack Growth in Low Alloy Reactor Pressure Vessel Steel

International Nuclear Information System (INIS)

Rui Wu; Sandstroem, Rolf; Seitisleam, Facredin

2004-02-01

Uni-axial creep and creep crack growth (CCG) tests at 320 deg C and 340 deg C as well as post test metallography have been carried out in a low alloy reactor pressure vessel steel (ASTM A508 class 2) having simulated coarse grained heat affected zone microstructure. The CCG behaviour is studied in terms of steady crack growth rate, creep fracture parameter C*, stress intensity factor and reference stress at given testing conditions. It has been found that CCG does occur at both tested temperatures. The lifetimes for the CCG tests are considerably shorter than those for the uni-axial creep tests. This is more pronounced at longer lifetimes or lower stresses. Increasing temperature from 320 deg C to 340 deg C causes a reduction of lifetime by approximately a factor of five and a corresponding increase of steady crack growth rate. For the CCG tests, there are three regions when the crack length is plotted against time. After incubation, the crack grows steadily until it accelerates when rupture is approached. Notable crack growth takes place at later stage of the tests. No creep cavitation is observed and transgranular fracture is dominant for the uni-axial creep specimens. In the CT specimens the cracks propagate intergranularly, independent of temperature and time. Some relations between time to failure, reference stress and steady crack growth rate are found for the CCG tests. A linear extrapolation based on the stress-time results indicates that the reference stress causing failure due to CCG at a given lifetime of 350,000 hours at 320 deg C is clearly lower than both yield and tensile strengths, on which the design stress may have based. Therefore, caution must be taken to prevent premature failure due to low temperature CCG. Both uni-axial and CCG tests on real welded joint at 320 deg C, study of creep damage zone at crack tip as well as numerical simulation are recommended for future work

Modeling on oxide dependent 2DEG sheet charge density and threshold voltage in AlGaN/GaN MOSHEMT

Science.gov (United States)

Panda, J.; Jena, K.; Swain, R.; Lenka, T. R.

2016-04-01

We have developed a physics based analytical model for the calculation of threshold voltage, two dimensional electron gas (2DEG) density and surface potential for AlGaN/GaN metal oxide semiconductor high electron mobility transistors (MOSHEMT). The developed model includes important parameters like polarization charge density at oxide/AlGaN and AlGaN/GaN interfaces, interfacial defect oxide charges and donor charges at the surface of the AlGaN barrier. The effects of two different gate oxides (Al2O3 and HfO2) are compared for the performance evaluation of the proposed MOSHEMT. The MOSHEMTs with Al2O3 dielectric have an advantage of significant increase in 2DEG up to 1.2 × 1013 cm-2 with an increase in oxide thickness up to 10 nm as compared to HfO2 dielectric MOSHEMT. The surface potential for HfO2 based device decreases from 2 to -1.6 eV within 10 nm of oxide thickness whereas for the Al2O3 based device a sharp transition of surface potential occurs from 2.8 to -8.3 eV. The variation in oxide thickness and gate metal work function of the proposed MOSHEMT shifts the threshold voltage from negative to positive realizing the enhanced mode operation. Further to validate the model, the device is simulated in Silvaco Technology Computer Aided Design (TCAD) showing good agreement with the proposed model results. The accuracy of the developed calculations of the proposed model can be used to develop a complete physics based 2DEG sheet charge density and threshold voltage model for GaN MOSHEMT devices for performance analysis.

Temperature dependent dynamics of DegP-trimer: A molecular dynamics study

Directory of Open Access Journals (Sweden)

Nivedita Rai

2015-01-01

Full Text Available DegP is a heat shock protein from high temperature requirement protease A family, which reacts to the environmental stress conditions in an ATP independent way. The objective of the present analysis emerged from the temperature dependent functional diversity of DegP between chaperonic and protease activities at temperatures below and above 28 °C, respectively. DegP is a multimeric protein and the minimal functional unit, DegP-trimer, is of great importance in understanding the DegP pathway. The structural aspects of DegP-trimer with respect to temperature variation have been studied using molecular dynamics simulations (for 100 ns and principal component analysis to highlight the temperature dependent dynamics facilitating its functional diversity. The DegP-trimer revealed a pronounced dynamics at both 280 and 320 K, when compared to the dynamics observed at 300 K. The LA loop is identified as the highly flexible region during dynamics and at extreme temperatures, the residues 46–80 of LA loop express a flip towards right (at 280 and left ( at 320 K with respect to the fixed β-sheet connecting the LA loop of protease for which Phe46 acts as one of the key residues. Such dynamics of LA loop facilitates inter-monomeric interaction with the PDZ1 domain of the neighbouring monomer and explains its active participation when DegP exists as trimer. Hence, the LA loop mediated dynamics of DegP-trimer is expected to provide further insight into the temperature dependent dynamics of DegP towards the understanding of its assembly and functional diversity in the presence of substrate.

A baseline for upper crustal velocity variations along the East Pacific Rise at 13 deg N

Science.gov (United States)

Kappus, Mary E.; Harding, Alistair J.; Orcutt, John A.

1995-04-01

A wide aperture profile of the East Pacific Rise at 13 deg N provides data necessary to make a high-resolution seismic velocity profile of the uppermost crust along a 52-km segment of ridge crest. Automated and objective processing steps, including r-p analysis and waveform inversion, allow the construction of models in a consistent way so that comparisons are meaningful. A continuous profile is synthesized from 70 independent one-dimensional models spaced at 750-km intervals along the ridge. The resulting seismic velocity structure of the top 500 m of crust is remarkable in its lack of variability. The main features are a thin low-velocity layer 2A at the top with a steep gradient to layer 2B. The seafloor velocity is nearly constant at 2.45 km/s +/- 3% along the entire ridge. The velocity at the top of layer 2B is 5.0 km/s +/- 10%. The depth to the 4 km/s isovelocity contour within layer 2A is 130 +/- 20 m from 13 deg to 13 deg 20 min N, north of which it increases to 180 m. The increase in thickness is coincident with a deviation from axial linearity (DEVAL) noted by both a slight change in axis depth and orientation and in geochemistry. The waveform inversion, providing more details plus velocity gradient information, shows a layer 2A with about 80 m of constant-velocity material underlain by 150 m of high velocity gradient material, putting the base of layer 2A at approximately 230 m depth south of 13 deg 20 min N and about 50 m thicker north of the DEVAL. The overall lack of variability, combined with other recent measurements of layer 2A thickness along and near the axis, indicates that the thickness of volcanic extrusives is controlled not by levels of volcanic productivity, but the dynamics of emplacement. The homogeneity along axis also provides a baseline of inherent variability in crustal structure of about 10% against which other observed variations in similar regimes can be compared.

Oxidation of Alloy 82 in nominal PWR primary water at 340 deg. C and in hydrogenated steam at 400 deg. C

International Nuclear Information System (INIS)

Chaumun, Elizabeth; Guerre Catherine; Duhamel, Cecilie; Sennour, Mohamed; Curieres, Ian-de

2012-09-01

Nickel-base weld metals are susceptible to stress corrosion cracking (SCC) in Pressurized Water Reactor (PWR) primary water. As tests in laboratory need to last, in some cases, at least several thousand hours to get stress corrosion crack initiation or propagation in simulated primary water, pure hydrogenated steam at 400 deg. C was used to perform accelerated tests. To confirm that these conditions are still representative of primary water conditions, results of oxidation tests of coupons in hydrogenated steam at 400 deg. C and in primary water at 340 deg. C have been compared. Surface oxide layers have been characterized in order to discuss the influence of the temperature and of the media (water or steam). (authors)

Il teatro degli spiriti.

Directory of Open Access Journals (Sweden)

Chiara Pussetti

2013-07-01

Full Text Available Questo saggio è dedicato a un culto di possessione, in cui tutte ledonne, investite dagli spiriti degli uomini morti prima dell’iniziazione, compiono un percorso iniziatico parallelo a quello maschile, consentendo a queste anime, potenzialmente pericolose, di completare il cammino che non hanno potuto percorrere da vivi e quindi di raggiungere serenamente il mondo dei morti, come antenati protettori del villaggio

Phosphorylation of DegU is essential for activation of amyE ...

Indian Academy of Sciences (India)

Gel filtration chromatography of DegU on Sephacryl. S100 (Methods). The native molecular weight of DegU was determined on a pre-calibrated Sephacryl S-100 ... Transferrin (80kDa), Alcohol Dehydrogenase (150 kDa). All the above markers were loaded individually. Purified DegU. (~1 mg), in a total volume of 1 mL was ...

Molecular transformers in the cell: lessons learned from the DegP protease-chaperone.

Science.gov (United States)

Sawa, Justyna; Heuck, Alexander; Ehrmann, Michael; Clausen, Tim

2010-04-01

Structure-function analysis of DegP revealed a novel mechanism for protease and chaperone regulation. Binding of unfolded proteins induces the oligomer reassembly from the resting hexamer (DegP6) into the functional protease-chaperone DegP12/24. The newly formed cage exhibits the characteristics of a proteolytic folding chamber, shredding those proteins that are severely misfolded while stabilizing and protecting proteins present in their native state. Isolation of native DegP complexes with folded outer membrane proteins (OMPs) highlights the importance of DegP in OMP biogenesis. The encapsulated OMP beta-barrel is significantly stabilized in the hydrophobic chamber of DegP12/24 and thus DegP seems to employ a reciprocal mechanism to those chaperones assisting the folding of water soluble proteins via polar interactions. In addition, we discuss in this review similarities to other complex proteolytic machines that, like DegP, are under control of a substrate-induced or stress-induced oligomer conversion.

Simulated cosmic microwave background maps at 0.5 deg resolution: Unresolved features

Science.gov (United States)

Kogut, A.; Hinshaw, G.; Bennett, C. L.

1995-01-01

High-contrast peaks in the cosmic microwave background (CMB) anisotropy can appear as unresolved sources to observers. We fit simluated CMB maps generated with a cold dark matter model to a set of unresolved features at instrumental resolution 0.5 deg-1.5 deg to derive the integral number density per steradian n (greater than absolute value of T) of features brighter than threshold temperature absolute value of T and compare the results to recent experiments. A typical medium-scale experiment observing 0.001 sr at 0.5 deg resolution would expect to observe one feature brighter than 85 micro-K after convolution with the beam profile, with less than 5% probability to observe a source brighter than 150 micro-K. Increasing the power-law index of primordial density perturbations n from 1 to 1.5 raises these temperature limits absolute value of T by a factor of 2. The MSAM features are in agreement with standard cold dark matter models and are not necessarily evidence for processes beyond the standard model.

Analytical models for the 2DEG concentration and gate leakage current in AlGaN/GaN HEMTs

Science.gov (United States)

Ahmed, Nadim; Dutta, Aloke K.

2017-06-01

In this paper, we present a completely analytical model for the 2DEG concentration in AlGaN/GaN HEMTs as a function of gate bias, considering the donor-like trap states present at the metal/AlGaN interface to be the primary source of 2DEG carriers. To the best of our knowledge, this is a completely new contribution of this work. The electric field in the AlGaN layer is calculated using this model, which is further used to model the gate leakage current under reverse bias. We have modified the existing TTT (Thermionic Trap-Assisted Tunneling) current model, taking into account the effect of both metal/AlGaN interface traps as well as AlGaN bulk traps. The gate current under forward bias is also modeled using the existing thermionic emission model, approximating it by its Taylor series expansion. To take into account the effect of non-zero drain-source bias (VDS), an empirical fitting parameter is introduced in order to model the channel voltage in terms of VDS. The results of our models have been compared with the experimental data reported in the literature for three different devices, and the match is found to be excellent for both forward and reverse bias as well as for zero and non-zero VDS.

Study of elementary mechanisms of creep in uranium as a function of temperature (150 deg. to 760 deg. C) by activation energy measurements

International Nuclear Information System (INIS)

Grenier, P.

1966-06-01

Creep tests were carried out on single crystals and polycrystalline specimens of uranium in both the α and β phases over the temperature range 150 - 760 deg. C. The determination of the activation energy for creep and the study of its variation with temperature made it possible to distinguish various temperature ranges in which one or more elementary mechanisms govern deformation. Micrographic observations after creep and the study of the variation of creep-rate with load support the conclusions. The creep behavior of single crystals is identical with that of polycrystalline material below 325 deg. C. From 325 deg. C to one upper limiting temperature whose value depends on the purity and previous history of the metal, the creep deformation of uranium is controlled by cross-slip. From this limiting temperature up to 520 deg. C, the creep of uranium involves two independent mechanisms operating simultaneously, the movement of screw dislocation by cross-slip and the climbing of edge dislocations out of their slip plane. Between 520 deg. C and the α - β transformation temperature creep in polycrystals is governed by the climb of edge dislocations out of their slip planes, by a pile up mechanism in the case of primary creep and by dipole annihilation in the case of secondary creep. In single crystals creep is dependent on the climb of edge dislocations into pre-existent sub-boundaries and their subsequent rearrangement within these boundaries. In the β phase the creep of polycrystals is governed by the diffusional climb of edge dislocations. Between 450 and 630 deg. C small alloy additions of molybdenum modify the creep characteristics of uranium although the deformation mechanisms involved are analogous to those in the pure metal. (author) [fr

Field-induced strain memory with non-180 .deg. domain-reorientation control

International Nuclear Information System (INIS)

Kadota, Yoichi; Hosaka, Hiroshi; Morita, Takeshi

2010-01-01

Using non-180 .deg. domain-reorientation control, we propose the strain memory effect in ferroelectric ceramics. Electric fields with asymmetric amplitudes were applied to soft-type lead zirconate titanate (PZT) ceramics, and the strain hysteresis and the polarization loop were measured. The butterfly curve became asymmetric under an electric field with a particular asymmetric amplitude. The asymmetric butterfly curve had two stable strain states at zero electric field. Thus, the strain memory effect was realized as the difference between the two stable strain states. An XRD analysis was carried out to verify the contribution of the non-180 .deg. domain reorientation to the strain memory effect. The non-180 .deg. domain reorientation was determined as the intensity ratio of the (002) to the (200) peak. The strain memory determined from macroscopic strain measurements had a linear relationship to the non-180 .deg. domain volume fraction. This result indicated the origin of the strain memory to be the non-180 .deg. domain reorientation.

Study of elementary mechanisms of creep in uranium as a function of temperature (150 deg. to 760 deg. C) by activation energy measurements; Etude des mecanismes elementaires de deformation par fluage de l'uranium en fonction de la temperature (de 150 deg. a 760 deg. C) par la mesure des energies d'activation

Energy Technology Data Exchange (ETDEWEB)

Grenier, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-07-01

Creep tests were carried out on single crystals and polycrystalline specimens of uranium in both the {alpha} and {beta} phases over the temperature range 150 - 760 deg. C. The determination of the activation energy for creep and the study of its variation with temperature made it possible to distinguish various temperature ranges in which one or more elementary mechanisms govern deformation. Micrographic observations after creep and the study of the variation of creep-rate with load support the conclusions. The creep behavior of single crystals is identical with that of polycrystalline material below 325 deg. C. From 325 deg. C to one upper limiting temperature whose value depends on the purity and previous history of the metal, the creep deformation of uranium is controlled by cross-slip. From this limiting temperature up to 520 deg. C, the creep of uranium involves two independent mechanisms operating simultaneously, the movement of screw dislocation by cross-slip and the climbing of edge dislocations out of their slip plane. Between 520 deg. C and the {alpha} - {beta} transformation temperature creep in polycrystals is governed by the climb of edge dislocations out of their slip planes, by a pile up mechanism in the case of primary creep and by dipole annihilation in the case of secondary creep. In single crystals creep is dependent on the climb of edge dislocations into pre-existent sub-boundaries and their subsequent rearrangement within these boundaries. In the {beta} phase the creep of polycrystals is governed by the diffusional climb of edge dislocations. Between 450 and 630 deg. C small alloy additions of molybdenum modify the creep characteristics of uranium although the deformation mechanisms involved are analogous to those in the pure metal. (author) [French] Des essais de fluage a diverses temperatures comprises entre 150 et 760 deg. C ont ete effectues sur des polycristaux et des monocristaux d'uranium, en phase {alpha} et en phase {beta}. La

Precipitate evolution in underaged Al-Mg-Si alloy during thermal cycling between 25 deg. C and 65 deg. C

International Nuclear Information System (INIS)

Uan, J.-Y.; Cho, C.-Y.; Chen, Z.-M.; Lin, J.-K.

2006-01-01

The evolution of metastable precipitates and the aging response in underaged Al-Mg-Si alloy during environmental temperature cycling was investigated using transmission electron microscopy (TEM) and hardness tests. After the alloy underwent thermal cycling between 25 deg. C and 65 deg. C, the hardness tests revealed that hardness decreased slightly, rather than following a concave downward curve, with the cycle times. Needle-shaped G.P. zones transformed during the environmental thermal cycling. The fraction of the zones declined sharply from almost 100% to only approximately 10% after 90 cycles, accompanied by an increase in the fraction of lath-shaped precipitates and the formation of β'' precipitates in the matrix. The precipitate developed with the 25-65 deg. C cycling time as follows: needle-shaped G.P. zones → lath-shaped ppt + β'' ppt + needle-shaped G.P. zones → lath-shaped ppt + β'' ppt + rod-shaped ppt + needle-shaped G.P. zones. Therefore, three or four precipitates coexisted in the underaged alloy following prolonged cycling. The formation of a limited number of β'' precipitates and the presence of a rod-shaped phase in the alloy during environmental temperature cycling reduced the hardness as the cycle time increases

The hydrolysis of iron(III) and iron(ll) ions between 25 deg C and 375 deg C

Energy Technology Data Exchange (ETDEWEB)

Lewis, Derek

1971-11-15

Some data on the stabilities of the known iron (III) and iron (II) ions are presented, that have been obtained in a theoretical study of the iron-water system at temperatures up to the critical temperature. In this study, estimates of the stability constants of the various ions in dilute solution have been made by a method based on the equations of classical thermodynamics and empirical equations for the change with temperature of ionic heat capacity. The data indicate that hydrolysis increases so rapidly with temperature that the Fe+3 - ion is practically non-existent above about 150 deg C and, except in very acid solutions, the Fe+2 - ion is a relatively minor constituent above about 250 deg C. The most stable of the ions over a wide range of conditions are probably Fe(OH){sub 2}+ , Fe(OH)+ and HFeO{sub 2}-

Cold resistance and metabolic activity of lichens below 0 degC

Science.gov (United States)

Kappen, L.; Schroeter, B.; Scheidegger, C.; Sommerkorn, M.; Hestmark, G.

Laboratory measurements show that lichens are extremely tolerant of freezing stress and of low-temperature exposure. Metabolic activity recovered quickly after severe and extended cold treatment. Experimental results demonstrate also that CO_2 exchange is already active at around -20 degC. The psychrophilic character of polar lichen species is demonstrated by optimum temperatures for net photosynthesis between 0 and 15 degC. In situ measurements show that lichens begin photosynthesizing below 0 degC if the dry thalli receive fresh snow. The lowest temperature measured in active lichens was -17 degC at a continental Antarctic site. The fine structure and the hydration state of photobiont and mycobiont cells were studied by low-temperature scanning electron microscopy (LTSEM) of frozen hydrated specimens. Water potentials of the frozen system are in the range of or even higher than those allowing dry lichens to start photosynthesis by water vapor uptake at +10 degC. The great success of lichens in polar and high alpine regions gives evidence of their physiological adaptation to low temperatures. In general lichens are able to persist through glacial periods, but extended snow cover and glaciation are limiting factors.

Measurement of Doppler effect up to 2000degC at FCA. 1

International Nuclear Information System (INIS)

Oigawa, Hiroyuki; Okajima, Shigeaki; Mukaiyama, Takehiko; Satoh, Kunio; Hishida, Makoto; Hayano, Mutsuhiko; Kudogh, Fumio; Kasahara, Yoshiyuki.

1994-03-01

A new experimental device for the measurement of 238 U Doppler effect up to 2000degC was developed for the Fast Critical Assembly (FCA) of Japan Atomic Energy Research Institute with the intention to improve the Doppler effect analysis at high temperature in fast reactors. The measurement method consists of two different techniques; one is the reactivity worth measurement with using a small sample heated up to 1500degC, the other is the reaction rate measurement with using a foil heated up to 2000degC. In the present work, the development and measurement for the former technique is described. The technique itself had been used in critical assemblies around the world, including FCA, for the measurement up to 800degC. The present new device was developed by improving the old device throughouly to extend the sample temperature up to 1500degC which is hot enough for us to evaluate the Doppler effect in the MOX-fuel fast reactor. (author)

Degradation of 2DEG transport properties in GaN-capped AlGaN/GaN heterostructures at 600 °C in oxidizing and inert environments

Science.gov (United States)

Hou, Minmin; Jain, Sambhav R.; So, Hongyun; Heuser, Thomas A.; Xu, Xiaoqing; Suria, Ateeq J.; Senesky, Debbie G.

2017-11-01

In this paper, the electron mobility and sheet density of the two-dimensional electron gas (2DEG) in both air and argon environments at 600 °C were measured intermittently over a 5 h duration using unpassivated and Al2O3-passivated AlGaN/GaN (with 3 nm GaN cap) van der Pauw test structures. The unpassivated AlGaN/GaN heterostructures annealed in air showed the smallest decrease (˜8%) in 2DEG electron mobility while Al2O3-passivated samples annealed in argon displayed the largest drop (˜70%) based on the Hall measurements. Photoluminescence and atomic force microscopy showed that minimal strain relaxation and surface roughness changes have occurred in the unpassivated samples annealed in air, while those with Al2O3 passivation annealed in argon showed significant microstructural degradations. This suggests that cracks developed in the samples annealed in air were healed by oxidation reactions. To further confirm this, Auger electron spectroscopy was conducted on the unpassivated samples after the anneal in air and results showed that extra surface oxides have been generated, which could act as a dislocation pinning layer to suppress the strain relaxation in AlGaN. On the other hand, similar 2DEG sheet densities were observed in passivated and unpassivated AlGaN/GaN samples at the end of the 5-h anneal in air or argon due to the combined impact of strain relaxation and changes in the ionized electronic states. The results support the use of unpassivated GaN-capped AlGaN/GaN heterostructures as the material platform for high-temperature electronics and sensors used in oxidizing environmental conditions.

Proteolytic activity of recombinant DegP from Chromohalobacter salexigens BKL5

Directory of Open Access Journals (Sweden)

Dewi Fitriani

2017-09-01

Conclusions: Recombinant DegP from C. salexigens BKL5 showed proteolytic activity when β-casein was used as a substrate. In silico analysis indicated that recombinant DegP had characteristics similar to those of halophilic proteins depending on its amino acid composition.

Restrained shrinkage experiments on coated particle fuel compacts in the temperature range 600-1200 deg C

International Nuclear Information System (INIS)

Blackstone, R.; Veringa, H.J.; Loelgen, R.

1976-05-01

Information on irradiation induced creep in reactor graphite and in fuel compact material is an essential ingredient in the design of any reactor core layout, because the creep plasticity of these materials diminishes the stresses which are built up in the fuel element during reactor operation. The restrained shrinkage method in which the shrinkage of a dumbbell shaped creep specimen is restrained by a graphite material which shows less irradiation shrinkage, offers a good possibility of performing a large series of tensile creep experiments in a limited irradiation volume. The irradiations, evaluations and the results of a series of restrained shrinkage experiments in which six different materials were tested, of which five were dummy coated particle compacts and one pure matrix material are described and discussed. These materials were irradiated in the High Flux Reactor of the Euratom Joint Research Centre in Petten/Netherlands. The irradiations were performed in three successive capsules at irradiation temperatures of 600 deg C, 900 deg C, 1050 deg C and 1200 deg C up to a neutron fluence of maximum 3x10 21 n.cm 2 (DNE). The post-irradiation examinations yielded plastic strains up to 2,3%, and values for the radiation creep coefficient were calculated, ranging from 4 to 8.10 -12 at 600 deg C and 8 to 30.10 -12 at 1200 deg C always given per dyn.cm -2 tensile stresses and per 10 20 n.cm -2 fluence units. Generally it was found that the creep behavior of these materials and the temperature dependence of the creep process could be compared with those for normal reactor graphites

Book review. La forma degli animali. Adolf Portmann

Directory of Open Access Journals (Sweden)

Manuel Graziani

2013-09-01

Full Text Available Nel 1931 il biologo Adolf Portmann era già talmente noto a livello internazionale per le sue ricerche da guadagnarsi la cattedra in zoologia nell'università della sua città natale, Basilea, all'età di appena 34 anni. All'attività di docente universitario ha sempre affiancato un'originale riflessione sul significato delle scienze della vita, imponendosi come una delle figure chiave nel dibattito tra biologia teoretica, estetica e antropologia filosofica. La forma degli animali, la sua opera più celebre, si pone al confine tra varie discipline e conserva un grande interesse ancora oggi che il dialogo tra estetica e biologia si è fatto nuovamente intenso. Pubblicata nel 1948 e in forma ampliata nel 1960 (da cui deriva questa prima edizione italiana a cura di Pietro Conte l'opera rappresenta il frutto più maturo delle sue ricerche "interdisciplinari".Un saggio che nasce dall'insoddisfazione nei confronti dei paradigmi scientifici consolidati e che ripropone l'idea morfologica in biologia sulla scorta del pensiero di J. W. Goethe il quale affermava che "tutto ciò che è deve anche dar cenno di sé e mostrarsi". Adolf Portmann è un convinto sostenitore che dalla forma si possano dedurne le complessive caratteristiche interne ed esterne degli animali. Secondo questa prospettiva la peculiare fisionomia dell'organismo dipende dalla congiunzione delle sue parti e dalle loro reciproche funzioni. Tuttavia l'autore non vede nello studio della forma l'alternativa al funzionalismo quanto, piuttosto, il suo necessario bilanciamento come dichiara nell'introduzione: "… per giungere alla conoscenza della vita animale di strade ce ne sono molte, e tutte possono contribuire ad arricchire la nostra esperienza. Questo lavoro si occupa della forma degli animali e si propone di mettere in luce la peculiare natura dell'aspetto visibile. Ci sono persone che si dedicano allo studio degli animali, conoscono moltissime specie, hanno imparato centinaia di nomi e

Using Paraffin with -10 deg C to 10 deg C Melting Point for Payload Thermal Energy Storage in SpaceX Dragon Trunk

Science.gov (United States)

Choi, Michael K.

2013-01-01

A concept of using paraffin wax phase change material (PCM) with a melting point between -10 deg C and 10 deg C for payload thermal energy storage in a Space Exploration Technologies (SpaceX) Dragon trunk is presented. It overcomes the problem of limited heater power available to a payload with significant radiators when the Dragon is berthed to the International Space Station (ISS). It stores adequate thermal energy to keep a payload warm without power for 6 hours during the transfer from the Dragon to an ExPRESS logistics carrier (ELC) on the ISS.

Rotary balance data for a single-engine agricultural airplane configuration for an angle-of-attack range of 8 deg to 90 deg

Science.gov (United States)

Mulcay, W. J.; Chu, J.

1980-01-01

Aerodynamic characteristics obtained in a helical flow environment utilizing a rotary balance located in the Langley spin tunnel are presented in plotted form for a 1/10 scale single engine agricultural airplane model. The configurations tested include the basic airplane, various wing leading edge and wing tip devices, elevator, aileron, and rudder control settings, and other modifications. Data are presented without analysis for an angle of attack range of 8 deg to 90 deg, and clockwise and counter-clockwise rotations covering a spin coefficient range from 0 to .9.

Keeping warming within the 2 deg. C limit after Copenhagen

International Nuclear Information System (INIS)

Macintosh, Andrew

2010-01-01

The object of the United Nations Climate Change Conference in Copenhagen in December 2009 was to reach an agreement on a new international legal architecture for addressing anthropogenic climate change post-2012. It failed in this endeavour, producing a political agreement in the form of the Copenhagen Accord. The Accord sets an ambitious goal of holding the increase in the global average surface temperature to below 2 deg. C. This paper describes 45 CO 2 -only mitigation scenarios that provide an indication of what would need to be done to stay within the 2 deg. C limit if the international climate negotiations stay on their current path. The results suggest that if developed countries adopt a combined target for 2020 of ≤20% below 1990 levels, global CO 2 emissions would probably have to be reduced by ≥5%/yr, and possibly ≥10%/yr, post-2030 (after a decade transitional period) in order to keep warming to 2 deg. C. If aggressive abatement commitments for 2020 are not forthcoming from all the major emitting countries, the likelihood of warming being kept within the 2 deg. C limit is diminutive.

Observation of the transition from diffusive regime to ballistic regime of the 2DEG transport property in Al xGa1-xN/GaN heterostructures

International Nuclear Information System (INIS)

Han, K.; Shen, B.; Tang, N.; Tang, Y.Q.; He, X.W.; Qin, Z.X.; Yang, Z.J.; Zhang, G.Y.; Lin, T.; Zhu, B.; Zhou, W.Z.; Chu, J.H.

2007-01-01

Electron-electron interaction effect of the two-dimensional electron gas (2DEG) in Al x Ga 1-x N/GaN heterostructures has been investigated by means of magnetotransport measurements at low temperatures. From the temperature dependence of the longitudinal conductivity of the heterostructures, a clear transition region has been observed. Based on the theoretical analysis, we conclude that this region corresponds to the transition from the diffusive regime to the ballistic regime of the 2DEG transport property. The interaction constant is determined to be -0.423, which is consistent with the theoretical prediction. However, the critical temperature for the transition, which is 8 K in Al x Ga 1-x N/GaN heterostructures, is much higher than the theoretical prediction

Comment on: "Current-voltage characteristics and zero-resistance state in 2DEG"

OpenAIRE

Cheremisin, M. V.

2003-01-01

We demonstrate that N(S)-shape current-voltage characteristics proposed to explain zero-resistance state in Corbino(Hall bar) geometry 2DEG (cond-mat/0302063, cond-mat/0303530) cannot account essential features of radiation-induced magnetoresistance oscillations experiments.

A DegU-P and DegQ-Dependent Regulatory Pathway for the K-state in Bacillus subtilis

Directory of Open Access Journals (Sweden)

Mathieu Miras

2016-11-01

Full Text Available The K-state in the model bacterium Bacillus subtilis is associated with transformability (competence as well as with growth arrest and tolerance for antibiotics. Entry into the K-state is determined by the stochastic activation of the transcription factor ComK and occurs in about ~15% of the population in domesticated strains. Although the upstream mechanisms that regulate the K-state have been intensively studied and are well understood, it has remained unexplained why undomesticated isolates of B. subtilis are poorly transformable compared to their domesticated counterparts. We show here that this is because fewer cells enter the K-state, suggesting that a regulatory pathway limiting entry to the K-state is missing in domesticated strains. We find that loss of this limitation is largely due to an inactivating point mutation in the promoter of degQ. The resulting low level of DegQ decreases the concentration of phosphorylated DegU, which leads to the de-repression of the srfA operon and ultimately to the stabilization of ComK. As a result, more cells reach the threshold concentration of ComK needed to activate the auto-regulatory loop at the comK promoter. In addition, we demonstrate that the activation of srfA transcription in undomesticated strains is transient, turning off abruptly as cells enter the stationary phase. Thus, the K-state and transformability are more transient and less frequently expressed in the undomesticated strains. This limitation is more extreme than appreciated from studies of domesticated strains. Selection has apparently limited both the frequency and the duration of the bistably expressed K-state in wild strains, likely because of the high cost of growth arrest associated with the K-state. Future modeling of K-state regulation and of the fitness advantages and costs of the K-state must take these features into account.

Characterization of Toxoplasma DegP, a rhoptry serine protease crucial for lethal infection in mice.

Directory of Open Access Journals (Sweden)

Gaelle Lentini

Full Text Available During the infection process, Apicomplexa discharge their secretory organelles called micronemes, rhoptries and dense granules to sustain host cell invasion, intracellular replication and to modulate host cell pathways and immune responses. Herein, we describe the Toxoplasma gondii Deg-like serine protein (TgDegP, a rhoptry protein homologous to High temperature requirement A (HtrA or Deg-like family of serine proteases. TgDegP undergoes processing in both types I and II strains as most of the rhoptries proteins. We show that genetic disruption of the degP gene does not impact the parasite lytic cycle in vitro but affects virulence in mice. While in a type I strain DegPI appears dispensable for the establishment of an infection, removal of DegPII in a type II strain dramatically impairs the virulence. Finally, we show that KO-DegPII parasites kill immunodeficient mice as efficiently as the wild-type strain indicating that the protease might be involved in the complex crosstalk that the parasite engaged with the host immune response. Thus, this study unravels a novel rhoptry protein in T. gondii important for the establishment of lethal infection.

Experimental formation of cronstedtite from Cox argillite-iron interaction at decreasing temperature in the 90 deg. C-40 deg. C range

International Nuclear Information System (INIS)

Pignatelli, Isabella; Mosser-Ruck, Regine; Rozsypal, Christophe; Truche, Laurent; Randi, Aurelien; Bartier, Daniele; Cathelineau, Michel; Ghanbaja, Jaafar; Mouton, Ludovic; Michau, Nicolas

2012-01-01

Document available in extended abstract form only. Cronstedtite crystals experimentally formed during a cooling experiment (90 deg.C-40 deg. C) simulating the time-temperature evolution of the iron-clay system around the steel overpacks in nuclear waste disposal, were characterized by XRD, SEM and TEM study. Cronstedtite is a T-O phyllosilicate with general formula (Fe 2+ 3-x Fe 3+ x )(Si 2-x Fe 3+ x )O 5 (OH) 4 , with 0 2 ), Callovo-Oxfordian argillite (COx) of the Paris Basin (with a solution/COx mass ratio of 10) and metal iron (powder and plates, with an iron powder/COx mass ratio of 0.5). This system was put in Teflon-line autoclaves heated at (90±2) deg. C for 6 months; then the temperature was decreased every month by step of 10 deg. C until 40 deg. C. The XRD results on run products clearly show that the T-O phyllosilicates crystallize and replace the predominant clay in the starting argillite, e.g. illite-smectite mixed-layer clays when the experimental temperature decreases. The reflections at 7.1 Angstrom, 4.76 Angstrom, 3.55 Angstrom and 2.73 Angstrom indicate that the T-O phyllosilicate formed is cronstedtite, but this technique is not efficient to determine its polytype. The SEM analyses confirm the presence of cronstedtite and show the morphological evolution of crystals with the temperature. At 90 deg. C three morphologies are recognized: trigonal pyramids and cones with hexagonal or rounded cross-section (Fig. 1), these crystals coexist with hairy berthierine-like minerals, as described by [10] and [12] The three cronstedtite shapes are observed until 70 deg. C and at lower temperatures the pyramidal morphology is dominant. From the energy dispersive X-ray analyses, structural formula of cronstedtite were calculated. The Fe II / Fe III ratio was adjusted to fix the octahedron to 3 in the calculation of the structural formula. Slight differences in the chemical compositions of cronstedtites are noticed: the pyramidal crystals have more Fe 2+ in the

First Ground-Based Infrared Solar Absorption Measurements of Free Tropospheric Methanol (CH3OH): Multidecade Infrared Time Series from Kitt Peak (31.9 deg N 111.6 deg W): Trend, Seasonal Cycle, and Comparison with Previous Measurements

Science.gov (United States)

Rinsland, Curtis P.; Mahieu, Emmanuel; Chiou, Linda; Herbin, Herve

2009-01-01

Atmospheric CH3OH (methanol) free tropospheric (2.09-14-km altitude) time series spanning 22 years has been analyzed on the basis of high-spectral resolution infrared solar absorption spectra of the strong vs band recorded from the U.S. National Solar Observatory on Kitt Peak (latitude 31.9degN, 111.6degW, 2.09-km altitude) with a 1-m Fourier transform spectrometer (FTS). The measurements span October 1981 to December 2003 and are the first long time series of CH3OH measurements obtained from the ground. The results were analyzed with SFIT2 version 3.93 and show a factor of three variations with season, a maximum at the beginning of July, a winter minimum, and no statistically significant long-term trend over the measurement time span.

Experimental transonic flutter characteristics of two 72 deg-sweep delta-wing models

Science.gov (United States)

Doggett, Robert V., Jr.; Soistmann, David L.; Spain, Charles V.; Parker, Ellen C.; Silva, Walter A.

1989-01-01

Transonic flutter boundaries are presented for two simple, 72 deg. sweep, low-aspect-ratio wing models. One model was an aspect-ratio 0.65 delta wing; the other model was an aspect-ratio 0.54 clipped-delta wing. Flutter boundaries for the delta wing are presented for the Mach number range of 0.56 to 1.22. Flutter boundaries for the clipped-delta wing are presented for the Mach number range of 0.72 to 0.95. Selected vibration characteristics of the models are also presented.

The LCF behaviour of SS AISI 304 in the temperature range between 450 deg. C and 850 deg. C in connection with life time predictions

International Nuclear Information System (INIS)

Bocek, M.; Petersen, C.; Schmitt, R.

The lifetime in high amplitude strain cycling with tensional hold periods is analysed presuming that creep failure damage is life determining. The life fraction rule (LFR) is used to calculate the lifetime consumpted during the dwell period in strain controlled tests as well as during tensional hold time stress cycles. It follows from the present investigation that stress relaxation occurring during the strain hold periods has a dominant influence upon the lifetime. The damage in stress relaxation is calculated by means of the LFR and the results are compared to experiments conducted on Zircaloy-4 (T=600 deg. C) and the austenitic stainless steel Type AISI 304 (T=650 deg. C). From the very good agreement between both it is concluded that under the loading conditions considered, creep failure damage is the main life determining damage contribution. To investigate the contributions of creep and fatigue to failure damage stress controlled experiments were conducted on AISI 304 at 550 deg. C and 850 deg. C. Whereas at the lower temperature (T 0.6 Tsub(s)) the lifetime increased with decreasing R. Therefrom it is concluded that in the case considered for T>0.6 Tsub(s) fatigue damage is not lifetime determining. (author)

Thermal conductivity of fully dense unirradiated UO2: A new formulation from experimental results between 100 deg. C and 2500 deg. C, and associated fundamental properties

International Nuclear Information System (INIS)

Delette, G.; Charles, M.

1997-01-01

The various contributions to the thermal conductivity of UO 2 are first reviewed: contribution from phonons is preponderant up to 1600 deg. C; radiative contribution is negligible in the case of a polycrystalline sample, and is unable to account for the increase in conductivity observed above 1600 deg. C; electronic contribution, which seems patently to be responsible for this increase, is efficient from 1400 deg. C (electron-hole pairs treated as small polarons). Given the lack of decisive arguments on their actual efficiency, it was decided that, for temperatures above 2400 deg. C, neither a possible decrease in the electronic contribution due to vacancies, nor an additional possible contribution from Frenkel pairs would be described. We do not go therefore beyond the above-mentioned electronic contribution. In the light of these considerations, the law established by CEA for the thermal conductivity of unirradiated UO 2 , on the basis of a homogeneous set of measurements between 100 deg. C and 2500 deg. C, has been revised. A least-square method applied to the above measurements was used to derive simultaneously the four adjustable constants of the law which is henceforth proposed: λ = 1/A + BT+C/T 2 exp(-W/kT). The values of A, B, C, and W obtained, have the advantage of giving a better account of the high temperature results compared to the Martin recommendations (which has, by the way, the same physical form as above). Furthermore, this new law allows an extrapolation towards the melting point which is better founded than the earlier CEA law, while still respecting the value of the integrated thermal conductivity up to melting. Finally, various burnup effects (impurities, stoichiometry, etc.) can be formulated in physical terms. Moreover, the values of various fundamental properties connected with the derived constants have been determined: Debye temperature, Grueneisen parameter, Mott-Hubbard energy, electrical conductivity. These values are discussed and

Breast compression and radiation dose in two different mammographic oblique projections: 45 and 60 deg

International Nuclear Information System (INIS)

Brnic, Zoran; Hebrang, Andrija

2001-01-01

Introduction: Standard mammography includes two views, craniocaudal and medio-lateral oblique. Depending on patient's body constitution, central beam angle in mediolateral oblique projection may vary, with 45 deg. being suitable for the majority of patients in routine daily practice. With continuous improvement in X-ray technology and radiographers' training, the risk of radiation induced cancerogenesis is considerably reduced and acceptable when compared to benefit. However, the risk still exists, being cumulative and directly related to absorbed glandular dose. There is no minimal dose of radiation which is absolutely harmless, and every effort to reduce the dose is welcome. In this retrospective study two different angles (45 vs. 60 deg.) of mediolateral oblique view were compared according to radiation dose and efficacy of breast compression. Patients and methods: In 52 women, additional 60 deg. oblique films were done after craniocaudal and mediolateral oblique 45 deg.-films, with the same kVp and positioning technique. Breast thickness, time-current products (mA s) and absorbed doses were compared between 45 deg. - and 60 deg.-films. Subgroups of women with large, small, prominent and pendulous breasts were analyzed separately, following the same methodology as for the whole group. Results: mA s were 11.5% lower and compression 7% better with an angle of 60 deg. than with 45 deg. In the subgroup of women with small breasts, mA s values were 13% lower and compression 9% better with 60 deg. than with 45 deg., while in the subgroup with large breasts, mA s were 9% lower and compression 5% better. In the subgroup of patients with pendulous breasts, mA s values were 12% lower and compression 10% better with 60 deg. than with 45 deg., while in the subgroup with prominent breasts, mA s values were 4% lower and compression 3% better. Absorbed glandular dose was estimated to be approximately 20% lower when an oblique mammogram was done with 60 deg. instead of 45 deg

Ingegneria degli acquiferi

CERN Document Server

Molfetta, Antonio

2012-01-01

Il testo fornisce le conoscenze necessarie per affrontare, con un approccio quantitativo, i molteplici aspetti connessi al flusso delle risorse idriche sotterranee (acque di falda) e alla propagazione e bonifica di contaminanti nei sistemi acquiferi. Vengono illustrate le proprietà fondamentali che definiscono la capacità di immagazzinamento, trasporto e rilascio dell’acqua negli acquiferi, e successivamente, descritte le metodiche per la determinazione di tali parametri tramite l’esecuzione e l’interpretazione di prove di falda, di pozzo e di laboratorio. A partire dalla classificazione chimico fisica-tossicologica dei contaminanti vengono, quindi, analizzati i meccanismi di propagazione e illustrate le soluzioni analitiche dell’equazione del trasporto di massa nei mezzi porosi. L’ultima parte del testo è dedicata alla caratterizzazione e bonifica degli acquiferi contaminati. Il testo è rivolto sia agli studenti universitari, sia ai professionisti che debbano affrontare con un approccio quantit...

Testimonianze di vittime degli anni di piombo

DEFF Research Database (Denmark)

Cecchini, Leonardo

Testimonianze di vittime degli anni di piombo In un articolo pubblicato nel 2008 sulla webzine Nazione indiana Christian Raimo criticava quello che poi Giovanni De Luna qualche anno dopo nel suo libro La Repubblica del dolore (2011) ha chiamato “paradigma vittimario”; cioè la presenza predominante...

Creep properties of EB welded copper overpack at 125-175 deg C

International Nuclear Information System (INIS)

Holmstroem, S.; Salonen, J.; Kinnunen, T.

2012-01-01

Electron Beam welds (EBW) chosen as primary sealing method by Posiva welding the over-pack canister lids of oxygen-free phosphorus micro-alloyed copper (OFP) have been tested for material properties relevant to long term creep life prediction. Creep rupture results are presented for the ruptured 175 deg C tests and for the ongoing long term tests at 150 deg C and 125 deg C. The current status (test time, creep strain and strain rate) of the ongoing tests are reported. The initial (175 deg C) results indicate that the EB welds are weaker than the parent material and that both round bar and spark eroded square test specimens produce weld strengths of about 0.75 at tests durations of 5000 h. The downward trend is however expected to continue for the longer test durations. The creep ductility shows decrease for the longer tests. Life estimates for the EB weld have been calculated at 100 deg C for both 50 and 80 MPa with the so far lowest measured EB weld strength factor (WSF=0.77). The state-of-the-art model on the available data give estimated lives of 21000 and 3000 years correspondingly. However, simulated to the expected temperature profile of the repository service the life fraction reached after 10000 years of service is 1 % and 7 % for the same stress levels. It is though important to remembered that the 80 MPa assumption is very conservative in nature and that the predictions do not take into account relaxation of stresses, further decline of the WSF or anisotropy of the weld and are therefore still to be considered indicative only. It is also to be remembered that there is only limited data in the long term regime for the weldments and that the estimates are based on the few EB data available in the public domain added with the Posiva data of this project. Improvement of the models and predictions are expected from the ongoing 125 deg C and 150 deg C long term tests. (orig.)

Influence of stress change on the fatigue behavior and fatigue life of aluminum oxide-dispersion-strengthening copper alloy at room temperature and 350degC

International Nuclear Information System (INIS)

Kawagoishi, Norio; Kondo, Eiji; Nisitani, Hironobu; Shimamoto, Atsunori; Tashiro, Rieko

2004-01-01

In order to investigate the influence of stress change on the fatigue behavior and fatigue life of an aluminum oxide-dispersion-strengthening copper alloy at elevated temperature, rotating bending fatigue tests were carried out under two-step loading at room temperature and 350degC. Both of static strength and fatigue strength decreased at 350degC. However, at the same relative stress σ a /σ B , fatigue life was longer at 350degC than at room temperature. Although the cumulative ratios Σ(N/N f ) were nearly unity for both the low to high and the high to low block loadings at room temperature, Miner's rule did not hold at 350degC. These results were related to the stress dependence on the log l-N/N f relation. That is, the crack length initiated at the same N/N f was larger in higher stress level at 350degC, whereas there was no stress dependence in the relation at room temperature. The stress dependence on the relation at 350degC was caused by the suppression of crack initiation due to the surface oxidation. (author)

Isothermal cross-sections of Hf-Sc-Ga(800 deg C) and Hf-Ti-Ga (750 deg C) phase diagrams

International Nuclear Information System (INIS)

Markiv, V.Ya.; Belyavina, N.N.

1981-01-01

Isothermal cross sections of Hf-Sc-Ga (800 deg C) and Hf-Ti-Ga (750 deg C) state diagrams are plotted. The existence of two ternary Hfsub(0.1-0.8)Scsub(0.9)-sub(0.2)Ga and Hfsub(0.8)Scsub(0.2)Gasub(3) phases is stated in the Hf-Sc-Ga system. The crystal structure of these compounds investigated by the powder method belongs to the structural α-MoB and ZrAl 3 types respectively. Continuous rows of (Hf, Sc 5 Ga 5 , (Hf, Ti)Ga 3 and (Hf, Ti)Ga 2 solid solutions are formed in the investigated systems. Essential quantity of the third component dissolve binary Sc 5 Ga 4 , Sc 2 Ga 3 (15 and 30 at % Hf respectively), Hf 5 Ga 4 , HfGa 2 (20, 10 at. % Sc), Hf 5 Ga 4 , HfGa, Hf 5 Ga 3 , Hf 2 Ga 3 (48, 30, 46, 20 at. % Ti) gallides [ru

Characterization of DegQVh, a serine protease and a protective immunogen from a pathogenic Vibrio harveyi strain.

Science.gov (United States)

Zhang, Wei-wei; Sun, Kun; Cheng, Shuang; Sun, Li

2008-10-01

Vibrio harveyi is an important marine pathogen that can infect a number of aquaculture species. V. harveyi degQ (degQ(Vh)), the gene encoding a DegQ homologue, was cloned from T4, a pathogenic V. harveyi strain isolated from diseased fish. DegQ(Vh) was closely related to the HtrA family members identified in other Vibrio species and could complement the temperature-sensitive phenotype of an Escherichia coli strain defective in degP. Expression of degQ(Vh) in T4 was modulated by temperature, possibly through the sigma(E)-like factor. Enzymatic analyses demonstrated that the recombinant DegQ(Vh) protein expressed in and purified from E. coli was an active serine protease whose activity required the integrity of the catalytic site and the PDZ domains. The optimal temperature and pH of the recombinant DegQ(Vh) protein were 50 degrees C and pH 8.0. A vaccination study indicated that the purified recombinant DegQ(Vh) was a protective immunogen that could confer protection upon fish against infection by V. harveyi. In order to improve the efficiency of DegQ(Vh) as a vaccine, a genetic construct in the form of the plasmid pAQ1 was built, in which the DNA encoding the processed DegQ(Vh) protein was fused with the DNA encoding the secretion region of AgaV, an extracellular beta-agarase. The E. coli strain harboring pAQ1 could express and secrete the chimeric DegQ(Vh) protein into the culture supernatant. Vaccination of fish with viable E. coli expressing chimeric degQ(Vh) significantly (P < 0.001) enhanced the survival of fish against V. harveyi challenge, which was possibly due to the relatively prolonged exposure of the immune system to the recombinant antigen produced constitutively, albeit at a gradually decreasing level, by the carrier strain.

Thermal conductivity of fully dense unirradiated UO{sub 2}: A new formulation from experimental results between 100 deg. C and 2500 deg. C, and associated fundamental properties

Energy Technology Data Exchange (ETDEWEB)

Delette, G; Charles, M [Commissariat a l` Energie Atomique, Grenoble (France)

1997-08-01

The various contributions to the thermal conductivity of UO{sub 2} are first reviewed: contribution from phonons is preponderant up to 1600 deg. C; radiative contribution is negligible in the case of a polycrystalline sample, and is unable to account for the increase in conductivity observed above 1600 deg. C; electronic contribution, which seems patently to be responsible for this increase, is efficient from 1400 deg. C (electron-hole pairs treated as small polarons). Given the lack of decisive arguments on their actual efficiency, it was decided that, for temperatures above 2400 deg. C, neither a possible decrease in the electronic contribution due to vacancies, nor an additional possible contribution from Frenkel pairs would be described. We do not go therefore beyond the above-mentioned electronic contribution. In the light of these considerations, the law established by CEA for the thermal conductivity of unirradiated UO{sub 2}, on the basis of a homogeneous set of measurements between 100 deg. C and 2500 deg. C, has been revised. A least-square method applied to the above measurements was used to derive simultaneously the four adjustable constants of the law which is henceforth proposed: {lambda} = 1/A + BT+C/T{sup 2}exp(-W/kT). The values of A, B, C, and W obtained, have the advantage of giving a better account of the high temperature results compared to the Martin recommendations (which has, by the way, the same physical form as above). Furthermore, this new law allows an extrapolation towards the melting point which is better founded than the earlier CEA law, while still respecting the value of the integrated thermal conductivity up to melting. Finally, various burnup effects (impurities, stoichiometry, etc.) can be formulated in physical terms. Moreover, the values of various fundamental properties connected with the derived constants have been determined: Debye temperature, Grueneisen parameter, Mott-Hubbard energy, electrical conductivity. These values

Phosphorylated DegU Manipulates Cell Fate Differentiation in the Bacillus subtilis Biofilm

Science.gov (United States)

Marlow, Victoria L.; Porter, Michael; Hobley, Laura; Kiley, Taryn B.; Swedlow, Jason R.; Davidson, Fordyce A.

2014-01-01

Cell differentiation is ubiquitous and facilitates division of labor and development. Bacteria are capable of multicellular behaviors that benefit the bacterial community as a whole. A striking example of bacterial differentiation occurs throughout the formation of a biofilm. During Bacillus subtilis biofilm formation, a subpopulation of cells differentiates into a specialized population that synthesizes the exopolysaccharide and the TasA amyloid components of the extracellular matrix. The differentiation process is indirectly controlled by the transcription factor Spo0A that facilitates transcription of the eps and tapA (tasA) operons. DegU is a transcription factor involved in regulating biofilm formation. Here, using a combination of genetics and live single-cell cytological techniques, we define the mechanism of biofilm inhibition at high levels of phosphorylated DegU (DegU∼P) by showing that transcription from the eps and tapA promoter regions is inhibited. Data demonstrating that this is not a direct regulatory event are presented. We demonstrate that DegU∼P controls the frequency with which cells activate transcription from the operons needed for matrix biosynthesis in favor of an off state. Subsequent experimental analysis led us to conclude that DegU∼P functions to increase the level of Spo0A∼P, driving cell fate differentiation toward the terminal developmental process of sporulation. PMID:24123822

Insight into DEG/ENaC channel gating from genetics and structure.

Science.gov (United States)

Eastwood, Amy L; Goodman, Miriam B

2012-10-01

The founding members of the superfamily of DEG/ENaC ion channel proteins are C. elegans proteins that form mechanosensitive channels in touch and pain receptors. For more than a decade, the research community has used mutagenesis to identify motifs that regulate gating. This review integrates insight derived from unbiased in vivo mutagenesis screens with recent crystal structures to develop new models for activation of mechanically gated DEGs.

Patologie sociali, resistenze e difese degli insegnanti nell’istituzione scolastica: Considerazioni cliniche e pedagogiche

Directory of Open Access Journals (Sweden)

Tommaso Fratini

2014-12-01

Full Text Available L’articolo prende in esame il tema di alcune resistenze e difese degli insegnanti all’interno dell’istituzione scolastica. Partendo dall’attuale condizione di emergenza della scuola italiana e rifacendosi al concetto di patologia sociale di Giuseppe Di Chiara, viene argomentato come tali resistenze coprano le angosce persecutorie degli insegnanti nel loro lavoro scolastico quotidiano nel rapporto con gli allievi. L’articolo, tra le varie forme di patologia istituzionale, affronta principalmente il tema di quelle che presiedono alle resistenze degli insegnanti al lavoro introspettivo con il proprio mondo interno, conseguenza e ulteriore cagione di sensi di colpa nel rapporto con gli allievi e di fenomeni di burnout lavorativo degli stessi insegnanti. Tali fenomeni vanno nella direzione del rinforzo sia di un atteggiamento di chiusura verso la collaborazione con professionisti esterni all’istituzione scolastica, sia di un atteggiamento di minore empatia e vicinanza emotiva con la realtà interna degli allievi.

Control of growth mode in SrTiO3 homoepitaxy under 500 deg. C

International Nuclear Information System (INIS)

Li Yanrong; Li Jinlong; Zhang Ying; Wei Xianhua; Deng Xinwu; Liu Xingzhao

2004-01-01

Homoepitaxial SrTiO 3 thin films were grown by laser molecular beam epitaxy. The growth mode was determined by in-situ reflective high energy electron diffraction, and the surface of the films was studied by ex-situ atomic force microscopy. At the deposition rate of 0.16A ring /sec and the laser energy density of 6J/cm 2 , layer-by-layer growth was observed above 460 deg. C substrate temperature, while the Stranski-Krastanov growth mode, that is layer-by-layer growth plus island growth mode, prevailed between 460 deg. C and 410 deg. C. On further decreasing the substrate temperature, the island growth was determined under 410 deg. C. With the optimization of deposition process in terms of laser energy density and deposition rate, the lowest crystallization temperatures of SrTiO 3 films grown in layer-by-layer growth mode were obtained as low as 280 deg. C. The effects of laser energy density on growth temperature were studied

Phase relationship in AL-Cu-Sc alloys at 450-500 deg C

International Nuclear Information System (INIS)

Kharakterova, M.L.

1991-01-01

Al-Cu-Sc alloys containing up to 40% Cu and up to 6% Sc at 450 deg C and 500 deg C are studied using light microscopy, X-ray-spectral microanalysis, X-ray diffraction analysis, scanning electron microscopy, measurement of microhardness and electric resistance. It is determined, that in equilibrium with aluminium solid solution under the given temperature ther are Al 3 Sc, CuAl 2 phases of the respective binary systems and W (ScCu 6.6-4 Al 5.4-8 ) ternary phase. Isothermal cross sections of Al-Cu-Sc system at 450 and 500 deg C are plotted. Microhardness of equilibrium phases is measured. Combined solubility of copper and scandium in aluminium is determined

Radiolysis of cesium iodide solutions at 35 and 85 deg C

International Nuclear Information System (INIS)

Lucas, M.

1981-09-01

An aqueous solution of cesium iodide was irradiated by the gamma rays from a cobalt 60 source with a dose rate of 0.4 Mrad/hr. At 35 deg C the iodide I - is oxidized in molecular iodine I 2 but at 85 deg C the iodate IO 3 - is obtained. The aim of this work is the study of aerosols behaviour released in accidental situation of a PWR in presence of steam [fr

Tirocinio e videomentoring: il punto di vista degli studenti

Directory of Open Access Journals (Sweden)

Carla Maltinti

2015-12-01

Full Text Available Il presente contributo analizza i commenti espressi dagli studenti del Corso di Studi in Scienze della Formazione Primaria dell’Università di Firenze dopo aver partecipato al primo anno di un nuovo percorso di tirocinio integrato da videomentoring.I feedback forniti dai tirocinanti sono stati esaminati con un duplice scopo: (i acquisire i giudizi, le percezioni, le emozioni degli studenti in rapporto all’esperienza effettuata; (ii ricavarne indicazioni per migliorare la proposta formativa.I dati raccolti, analizzati attraverso una content analysis, toccano aspetti fondamentali della formazione iniziale degli insegnanti, quali il modellamento, l’importanza del rapporto con il tutor, la riflessività, l’imbarazzo dei tirocinanti nel vedersi in azione.

submitter Technical Note: Using DEG-CPCs at upper tropospheric temperatures

CERN Document Server

Wimmer, D; Nieminen, T; Duplissy, J; Ehrhart, S; Almeida, J; Rondo, L; Franchin, A; Kreissl, F; Bianchi, F; Manninen, H E; Kulmala, M; Curtius, J; Petäjä, T

2015-01-01

Over the last few years, several condensation particle counters (CPCs) capable of measuring in the sub-3 nm size range have been developed. Here we study the performance of CPCs based on diethylene glycol (DEG) at different temperatures during Cosmics Leaving OUtdoor Droplets (CLOUD) measurements at CERN. The data shown here are the first set of verification measurements for sub-3 nm CPCs under upper tropospheric temperatures using atmospherically relevant aerosol particles. To put the results in perspective we calibrated the DEG-CPC at room temperature, resulting in a cut-off diameter of 1.4 nm. All diameters refer to mobility equivalent diameters in this paper. At upper tropospheric temperatures ranging from 246.15 K to 207.15 K, we found cut-off sizes relative to a particle size magnifier in the range of 2.5 to 2.8 nm. Due to low number concentration after size classification, the cut-off diameters have a high uncertainty (±0.3 nm) associated with them. Operating two laminar flow DEG-CPCs with different c...

La valutazione degli investimenti finanziati tramite equity crowdfunding

OpenAIRE

Zanetti, Laura

2015-01-01

Evoluzione e dimensione del crowdfunding, La valutazione e strutturazione dell’investimento tramite equity crowdfunding, Valutazioni implicite nelle raccolte fondi in equity crowdfunding, Peculiarità specifiche dell’equity crowdfunding, Un confronto con la bolla valutativa delle aziende internet degli anni 2000

Distance and total column density to the periodic radio star LSI + 61 deg 303

International Nuclear Information System (INIS)

Frail, D.A.; Hjellming, R.M.

1991-01-01

New observations toward the periodic radio star LSI + 61 deg 303 in the lines of H I at 21 cm and CO-18 at 2.7 mm are reported. Using the kinematic method, H I observations are interpreted in terms of the two-armed spiral shock model of Roberts (1972) to derive a distance to LSI + 61 deg 303 of 2.0 + or - 0.2 kpc. The results clearly show the presence of the Perseus arm shock and locate LSI + 61 deg 303 between this shock and the more distant postshock gas. In addition, by using the H I and CO-18 data, the total neutral and molecular gas column density is derived along the line of sight toward LSI + 61 deg 303. 32 refs

Wind-tunnel investigation of the flow correction for a model-mounted angle of attack sensor at angles of attack from -10 deg to 110 deg. [Langley 12-foot low speed wind tunnel test

Science.gov (United States)

Moul, T. M.

1979-01-01

A preliminary wind tunnel investigation was undertaken to determine the flow correction for a vane angle of attack sensor over an angle of attack range from -10 deg to 110 deg. The sensor was mounted ahead of the wing on a 1/5 scale model of a general aviation airplane. It was shown that the flow correction was substantial, reaching about 15 deg at an angle of attack of 90 deg. The flow correction was found to increase as the sensor was moved closer to the wing or closer to the fuselage. The experimentally determined slope of the flow correction versus the measured angle of attack below the stall angle of attack agreed closely with the slope of flight data from a similar full scale airplane.

Pourbaix diagrams for the system copper-chlorine at 5-100 deg C

International Nuclear Information System (INIS)

Beverskog, B.; Puigdomenech, I.

1998-04-01

Pourbaix diagrams for the copper-chlorine system in the temperature interval 5-100 deg C have been revised. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of each dissolved element, 10 -4 and 10 -6 molal for copper and 0.2 and 1.5 molal for chlorine have been used in the calculations. Chloride is the predominating chlorine species in aqueous solutions. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. CuCl 2 · 3Cu(OH) 2 is the only copper-chloride solid phase that forms at the concentrations of chlorine studied. However, its stability area decreases with increasing temperature. The ion CuCl 2 - predominates at all temperatures at [Cl(aq)] tot =0.2 molal and this reduces the immunity and passivity areas. A corrosion region exists between the immunity and passivity regions at 100 deg C at [Cu(aq)] tot =10 -6 and [Cl(aq)] tot =0.2 molal. At the chlorine concentration of 1.5 molal the corrosion region exists in the whole temperature range investigated. The ion CuCl 3 2- predominates at 5-25 and 100 deg C, while CuCl 2 - predominates at 50-80 deg C at [Cl(aq)] tot= 1-5 molal. A copper concentration of 10 -4 molal reduces the corrosion areas due to expansion of the immunity and passivity areas. However, a corrosion region still exists between the immunity and passivity regions at all investigated temperatures at pH Τ -6 molal and the chloride concentration of 0.2 molal. However, at 80-100 deg C the equilibrium potentials postulated for the Swedish nuclear repository are dangerously close to a corrosion situation. According to our calculations the copper canisters in the Swedish repository corrode at 80-100 deg C at the chloride concentration of 1.5 molal

Frictional property of glass-like carbon heat-treated at 1000-3000 deg. C

International Nuclear Information System (INIS)

Nakamura, Kazumasa; Sano, Takanori; Shindo, Hitoshi

2008-01-01

Frictional coefficient 'f' was measured in the air and in water at glass-like carbon (GLC) surfaces heat-treated between 1000 and 3000 deg. C. GLCs heat-treated at higher temperature had smoother and more hydrophobic faces, and lower f. The f was smaller than 0.10 for GLCs heat-treated at and above 2000 deg. C, which indicates their applicability as a solid lubricant or a self-lubricating material. The f = 0.06 observed for GLC heat-treated at 3000 deg. C was nearly the same as that of pyrolytic graphite (PG). Slightly lower f's were obtained in water than in the air

U-Th isotopic systematics at 13deg N east Pacific Ridge segment

International Nuclear Information System (INIS)

Ben Othman, D.; Allegre, C.J.

1990-01-01

Fresh basaltic glasses have been analyzed for U-Th disequilibrium systematics as part of an extensive study on the East Pacific Rise (EPR) at 12deg 45'N. These samples are well described in terms of major and trace elements as well as in Nd, Pb and Sr isotopes. Our results show significant heterogeneities in the mantle source at a small scale, and show heterogeneities at larger scales also when compared to other EPR data. U and Th concentration and isotopic data rule out fractional crystallization as a main process and support a mixing model in agreement with the marble cake model developed by Allegre and Turcotte and constrained by trace elements and Nd, Sr and Pb isotopes on the same samples by Prinzhofer et al. Based on the high ( 230 Th/ 232 Th) isotopic ratios on recent tholeiites especially the Th/U values inferred for their sources clearly show that the upper mantle Th/U has decreased with time. (orig.)

DEG/ENaC ion channels involved in sensory transduction are modulated by cold temperature

Science.gov (United States)

Askwith, Candice C.; Benson, Christopher J.; Welsh, Michael J.; Snyder, Peter M.

2001-01-01

Several DEG/ENaC cation channel subunits are expressed in the tongue and in cutaneous sensory neurons, where they are postulated to function as receptors for salt and sour taste and for touch. Because these tissues are exposed to large temperature variations, we examined how temperature affects DEG/ENaC channel function. We found that cold temperature markedly increased the constitutively active Na+ currents generated by epithelial Na+ channels (ENaC). Half-maximal stimulation occurred at 25°C. Cold temperature did not induce current from other DEG/ENaC family members (BNC1, ASIC, and DRASIC). However, when these channels were activated by acid, cold temperature potentiated the currents by slowing the rate of desensitization. Potentiation was abolished by a “Deg” mutation that alters channel gating. Temperature changes in the physiologic range had prominent effects on current in cells heterologously expressing acid-gated DEG/ENaC channels, as well as in dorsal root ganglion sensory neurons. The finding that cold temperature modulates DEG/ENaC channel function may provide a molecular explanation for the widely recognized ability of temperature to modify taste sensation and mechanosensation. PMID:11353858

The air oxidation behavior of lanthanum ion implanted zirconium at 500 deg. C

CERN Document Server

Peng, D Q; Chen, X W; Zhou, Q G

2003-01-01

The beneficial effect of lanthanum ion implantation on the oxidation behavior of zirconium at 500 deg. C has been studied. Zirconium specimens were implanted by lanthanum ions using a MEVVA source at energy of 40 keV with a fluence range from 1x10 sup 1 sup 6 to 1x10 sup 1 sup 7 ions/cm sup 2 at maximum temperature of 130 deg. C, The weight gain curves were measured after being oxidized in air at 500 deg. C for 100 min, which showed that a significant improvement was achieved in the oxidation behavior of zirconium ion implanted with lanthanum compared with that of the as-received zirconium. The valence of the oxides in the scale was analyzed by X-ray photoemission spectroscopy; and then the depth distributions of the elements in the surface of the samples were obtained by Auger electron spectroscopy. Glancing angle X-ray diffraction at 0.3 deg. incident angles was employed to examine the modification of its phase transformation because of the lanthanum ion implantation in the oxide films. It was obviously fou...

Quantitative cine-left ventriculography - Superiority of 45 .deg. RAO view to straight AB view -

International Nuclear Information System (INIS)

Lim, Tae Hwan; Han, Man Chung

1981-01-01

The volumetry by cineangiocardiography is known to have the most diagnostic and prognostic value in the evaluation of various valvular heart diseases and ischemic heart diseases. Although many authors favor the area-length method for the volumetry of left ventricle, 45 .deg. RAO projection seems to be more simple, inexpensive and accurate technique, considering the positional relationship of cardiac valves and obliquity of the long axis of left ventricle within the chest cage. Authors present the anatomical, geometrical and radiological basis for the superiority of 45 .deg. RAO protection by analyzing 20 normal heart specimen and 115 cineangiocardiograms of valvular heart diseases, and the results as follows: 1. Blood flow and motility of the mitral and aortic valves can be more clearly demonstrated by 45 .deg. RAO projection than by AP view. 2. The long diameter of left ventricular silhouette made 45 .deg. RAO projection reflects 90% or more of real diameter. 3. In RAO 45 .deg. position, patient's left nipple is optimal and convenient level for the ruler offering accurate magnification coefficient of left ventricle. 4. Ejection fraction after the extrasystole is exaggerated regardless of the left ventricular function, so it is desirable to exclude the 2 or 3 beats after extrasystole

Physical properties of concrete under 3-years exposure to high temperatures up to 110degC

International Nuclear Information System (INIS)

Nishiuchi, T.; Kanazu, T.; Ishida, H.

1990-01-01

Concrete structural members in a storehouse of high level radioactive wastes are designed assuming that they may be subjected to elevated temperature for a long term. So, in this study, concrete properties under temperature conditions (between 65degC-temperature limitation specified in design and 110degC-vaporing temperature of gel water in concrete) and possibility of raising this temperature limitation has been investigated from the view point of long term concrete properties. In this experiment, many properties of concrete were examined, such as compressive strength, tensile strength. Young's modulus, weight loss, pore size distribution under combined conditions (temperature conditions, mix proportions of concrete, moisture conditions). Followings are the main conclusions obtained within the limit of the experiment. 1. Compressive strength of concrete becomes smaller according as temperature becomes high, but there is little difference between the compressive strength at 65degC and 85degC. 2. Young's modulus of concrete decreases linearly according as temperature becomes higher. 3. Weight loss of concrete increases according as temperature becomes higher. 4. Judging from the decreasing rate of physical properties of concrete, it seems possible to raise temperature limitation from 65degC to 85degC. (author)

Ce2O3-SO3-H2O system at 150 and 200 deg C

International Nuclear Information System (INIS)

Belokoskov, V.I.; Trofimov, G.V.; Govorukhina, O.A.

1978-01-01

The solubility, solid phase composition and crystal characteristics in the Ce 2 O 3 -SO 3 -H 2 O system have been studied in a broad range of sulfuric acid concentrations (25 to 80% SO 3 ) at temperatures from 150 to 200 deg C. It has been established that in the system the equilibrium had been reached after 15 to 20 days. At 150 deg C, Ce 2 (SO 4 ) 3 x2H 2 O, Ce 2 (SO 4 ) 3 xH 2 O sulfates and Ce 2 (SO 4 ) 3 x3H 2 SO 4 acid salt crystallize in the system. At 200 deg C, the same sulfates crystallize in the system, except that the bisaturation points of the system are shifted, with respect to 150 deg C, into the region of higher SO 3 concentration and correspond to solutions with a SO 3 concentration of 57.8 and 65%. The solubility of cerium(3) at 150 deg C is about 0.5% Ce 2 O 3 . An increase in temperature up to 200 deg C leads to a slightly higher solubility of cerium sulfates

Pourbaix diagrams for the system copper-chlorine at 5-100 deg C

Energy Technology Data Exchange (ETDEWEB)

Beverskog, B. [Studsvik Material AB, Nykoeping (Sweden); Puigdomenech, I. [Studsvik Eco and Safety AB, Nykoeping (Sweden)

1998-04-01

Pourbaix diagrams for the copper-chlorine system in the temperature interval 5-100 deg C have been revised. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of each dissolved element, 10{sup -4} and 10{sup -6} molal for copper and 0.2 and 1.5 molal for chlorine have been used in the calculations. Chloride is the predominating chlorine species in aqueous solutions. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. CuCl{sub 2} {center_dot} 3Cu(OH){sub 2} is the only copper-chloride solid phase that forms at the concentrations of chlorine studied. However, its stability area decreases with increasing temperature. The ion CuCl{sub 2}{sup -} predominates at all temperatures at [Cl(aq)]{sub tot}=0.2 molal and this reduces the immunity and passivity areas. A corrosion region exists between the immunity and passivity regions at 100 deg C at [Cu(aq)]{sub tot}=10{sup -6} and [Cl(aq)]{sub tot}=0.2 molal. At the chlorine concentration of 1.5 molal the corrosion region exists in the whole temperature range investigated. The ion CuCl{sub 3}{sup 2-} predominates at 5-25 and 100 deg C, while CuCl{sub 2}{sup -} predominates at 50-80 deg C at [Cl(aq)]{sub tot=}1-5 molal. A copper concentration of 10{sup -4} molal reduces the corrosion areas due to expansion of the immunity and passivity areas. However, a corrosion region still exists between the immunity and passivity regions at all investigated temperatures at pH{sub {Tau}}<9.5 and 1.5 molal chloride concentration. According to our calculations the copper canisters in the deep nuclear waste repository should not corrode at the copper concentration of 10{sup -6} molal and the chloride concentration of 0.2 molal. However, at 80-100 deg C the equilibrium potentials postulated for the Swedish nuclear repository are dangerously close to a corrosion situation. According to

Irradiation Effects at 160-240 deg C in Some Swedish Pressure Vessel Steels

Energy Technology Data Exchange (ETDEWEB)

Grounes, M [AB Atomenergi, Nykoeping (Sweden); Myers, H P [Chalmers Institute of Technology, Goeteborg (Sweden); Hannerz, N E [Motala Verkstads AB, Motala (Sweden)

1967-09-15

Tensile specimens, Charpy impact specimens and miniature impact specimens of six steels in different conditions were irradiated to 2.8 x 10{sup 18} and 5.6 x 10{sup 18} n/cm{sup 2} (> 1 MeV) at 160-240 deg C. The steels investigated were SIS 142103, 2103/R3, NO 345, Fortiweld, Fortiweld HS and OK 54 P. There is no correlation between the increase in transition temperature and initial transition temperature. However, changes in strength and ductility can be correlated to the initial yield strength. The increases in transition temperature due to strain aging and irradiation are approximately additive. The irradiation-induced changes in 2103/R3 and Fortiweld HS steels do not vary with position in the thickness of the plate. Different tempering treatments in Fortiweld HS steel do not change the extent of irradiation effects. Normal Charpy V-notch impact specimens and miniature specimens give the same irradiation-induced increase in transition temperature.

Irradiation Effects at 160-240 deg C in Some Swedish Pressure Vessel Steels

International Nuclear Information System (INIS)

Grounes, M.; Myers, H.P.; Hannerz, N.E.

1967-09-01

Tensile specimens, Charpy impact specimens and miniature impact specimens of six steels in different conditions were irradiated to 2.8 x 10 18 and 5.6 x 10 18 n/cm 2 (> 1 MeV) at 160-240 deg C. The steels investigated were SIS 142103, 2103/R3, NO 345, Fortiweld, Fortiweld HS and OK 54 P. There is no correlation between the increase in transition temperature and initial transition temperature. However, changes in strength and ductility can be correlated to the initial yield strength. The increases in transition temperature due to strain aging and irradiation are approximately additive. The irradiation-induced changes in 2103/R3 and Fortiweld HS steels do not vary with position in the thickness of the plate. Different tempering treatments in Fortiweld HS steel do not change the extent of irradiation effects. Normal Charpy V-notch impact specimens and miniature specimens give the same irradiation-induced increase in transition temperature

Tensile properties of Zr-2.5 Nb pressure tube alloy between 25 and 800 degC

International Nuclear Information System (INIS)

Singh, R.N.; Kishore, R.; Sinha, T.K.; Banerjee, S.

2000-10-01

Tensile properties of zirconium-2.5 wt. % niobium pressure tube material were evaluated by uniaxial tension tests at temperatures between 25 and 800 degC and under strain-rates varying from 3.3 x 10 -5 to 3.3 x 10 -3 /s. Tests were carried out on specimens fabricated from the sections of finished (autoclaved) tubes as well as on those machined from the sections of cold worked (2 nd pilgered) tubes. Moreover, specimens fabricated from finished tubes belonging to twenty different heats were tested at 300 degC to study the heat to heat variation in tensile properties of this alloy. In order to study the effect of the crystallographic texture on the tensile properties, specimens oriented in longitudinal as well as, in transverse directions of the tubes were also tested. Results showed that both yield and ultimate tensile strengths of this alloy decreased monotonically with increasing test temperatures, with a rapid fall in strengths above a temperature of 350 degC (623 K). The tensile ductility did not change appreciably up to 400 degC (673K) but increased rapidly above this temperature. The observed results on the temperature dependence of the strength and ductility indicated the possible occurrence of dynamic strain-ageing in this alloy in the temperature range of 200-300 degC (473 to 573 K). The transverse specimens showed higher strengths and lower ductility as compared to those of the longitudinal specimens up to a temperature of 350 degC (623 K). Above 350 degC, the difference in the strengths and the ductility of the two types of the specimens, became negligibly small indicating that the texture did not appreciably influence the tensile properties of this alloy at temperatures exceeding 350 degC. The alloy developed extensive superplasticity (ductility exceeding 100 %), when tested in the temperature range of 650-800 degC. Maximum ductility values of 650 % for longitudinal and 900 % for the transverse orientation with strain-rate sensitivity (m) exceeding 0

The tensile properties of alloys 800H and 617 in the range 20 to 950deg C

International Nuclear Information System (INIS)

Abd El-Azim, M.E.; Ennis, P.J.; Schuster, H.; Nickel, H.

1990-01-01

The tensile properties of Alloy 800H and Alloy 617 in the solution treated condition and after ageing or carburization have been determined for the temperature range 20 to 950deg C. It was found that ageing at 900deg C prior to testing led to an increase in strength and a decrease in ductility at test temperatures up to 700deg C. Above 700deg C, there was no significant difference between the tensile properties of solution treated and aged material. Carburization caused a severe loss of ductility in both alloys at temperatures of 20 to around 800deg C, but the ductility increased sharply at test temperatures above 800deg C, accompanied by a change in the fracture mode from fracture of the carbide particles themselves to void formation and separation at the carbide/matrix interface. The correlation between tensile properties and creep data was investigated in tests carried out at different strain rates. Reasonable agreement was found at 800 to 950deg C for Alloy 617 and at 800 to 900deg C for Alloy 800H. Strain ageing effects were observed in both alloys at some temperatures and strain rates; these effects were serrated flow, negative strain rate sensitivity, peaks in the normalized UTS-temperature curves and plateaus in the elongation-temperature curves. The experimental results were interpreted in the light of two current models for strain ageing, the dislocation-dislocation interaction model and the dislocation-solute interaction model. (orig.) [de

Dynamic Longitudinal and Directional Stability Derivatives for a 45 deg. Sweptback-Wing Airplane Model at Transonic Speeds

Science.gov (United States)

Bielat, Ralph P.; Wiley, Harleth G.

1959-01-01

An investigation was made at transonic speeds to determine some of the dynamic stability derivatives of a 45 deg. sweptback-wing airplane model. The model was sting mounted and was rigidly forced to perform a single-degree-of-freedom angular oscillation in pitch or yaw of +/- 2 deg. The investigation was made for angles of attack alpha, from -4 deg. to 14 deg. throughout most of the transonic speed range for values of reduced-frequency parameter from 0.015 to 0.040 based on wing mean aerodynamic chord and from 0.04 to 0.14 based on wing span. The results show that reduced frequency had only a small effect on the damping-in-pitch derivative and the oscillatory longitudinal stability derivative for all Mach numbers M and angles of attack with the exception of the values of damping coefficient near M = 1.03 and alpha = 8 deg. to 14 deg. In this region, the damping coefficient changed rapidly with reduced frequency and negative values of damping coefficient were measured at low values of reduced frequency. This abrupt variation of pitch damping with reduced frequency was a characteristic of the complete model or wing-body-vertical-tail combination. The damping-in-pitch derivative varied considerably with alpha and M for the horizontal-tail-on and horizontal-tail-off configurations, and the damping was relatively high at angles of attack corresponding to the onset of pitch-up for both configurations. The damping-in-yaw derivative was generally independent of reduced frequency and M at alpha = -4 deg. to 4 deg. At alpha = 8 deg. to 14 deg., the damping derivative increased with an increase in reduced frequency and alpha for the configurations having the wing, whereas the damping derivative was either independent of or decreased with increase in reduced frequency for the configuration without the wing. The oscillatory directional stability derivative for all configurations generally decreased with an increase in the reduced-frequency parameter, and, in some instances

Reclutamento e formazione dei poliziotti: il caso degli ufficiali della gendarmeria francese

Directory of Open Access Journals (Sweden)

François Dieu

2007-04-01

Full Text Available Partendo dal caso degli ufficiali della gendarmeria francese, questo articolo illustra il modo in cui il reclutamento e la formazione possono contribuire, informalmente, alla ripartizione del potere nelle organizzazioni di polizia. Tramite la diversità delle vie di reclutamento si costituisce, di fatto, un vero e proprio sistema di "caste", con una stratificazione degli ufficiali in tre livelli gerarchici, che produce, al di là dei principi meritocratici, delle ineguaglianze manifeste nella ripartizione del potere nell'organizzazione della gendarmeria.

Post-deposition thermal annealing studies of hydrogenated microcrystalline silicon deposited at 40 deg. C

International Nuclear Information System (INIS)

Bronsveld, P.C.P.; Wagt, H.J. van der; Rath, J.K.; Schropp, R.E.I.; Beyer, W.

2007-01-01

Post-deposition thermal annealing studies, including gas effusion measurements, measurements of infrared absorption versus annealing state, cross-sectional transmission electron microscopy (X-TEM) and atomic force microscopy (AFM), are used for structural characterization of hydrogenated amorphous and microcrystalline silicon films, prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) at low substrate temperature (T S ). Such films are of interest for application in thin semiconductor devices deposited on cheap plastics. For T S ∼ 40 deg. C, H-evolution shows rather complicated spectra for (near-) microcrystalline material, with hydrogen effusion maxima seen at ∼ 200-250 deg. C, 380 deg. C and ∼ 450-500 deg. C, while for the amorphous material typical spectra for good-quality dense material are found. Effusion experiments of implanted He demonstrate for the microcrystalline material the presence of a rather open (void-rich) structure. A similar tendency can be concluded from Ne effusion experiments. Fourier Transform infrared (FTIR) spectra of stepwise annealed samples show Si-H bond rupture already at annealing temperatures of 150 deg. C. Combined AFM/X-TEM studies reveal a columnar microstructure for all of these (near-) microcrystalline materials, of which the open structure is the most probable explanation of the shift of the H-effusion maximum in (near-) microcrystalline material to lower temperature

Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 8 deg to 90 deg. 2: High-wing model C

Science.gov (United States)

Hultberg, R. S.; Chu, J.

1980-01-01

Aerodynamic characteristics obtained in a helical flow environment utilizing a rotary balance located in the Langley spin g tunnel are presented in plotted form for a 1/6 scale, single engine, high wing, general aviation model. The configurations tested included the basic airplane and control deflections, wing leading edge devices, tail designs, and airplane components. Data are presented without analysis for an angle of attack range of 8 deg to 90 deg and clockwise and counter clockwise rotations covering a spin coefficient range from 0 to 0.9.

Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 8 deg to 90 deg. 2: Low-wing model B

Science.gov (United States)

Bihrle, W., Jr.; Hultberg, R. S.

1979-01-01

Aerodynamic characteristics obtained in a rotational flow environment utilizing a rotary balance located in the spin tunnel are presented in plotted form for a 1/6.5 scale, single engine, low wing, general aviation airplane model. The configurations tested included the basic airplane, various wing leading-edge devices, tail designs, and rudder control settings as well as airplane components. Data are presented without analysis for an angle-of-attack range of 8 deg to 90 deg and clockwise and counter-clockwise rotations covering an (omega)(b)/2V range from 0 to 0.85.

Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 8 deg to 90 deg. 1: High-wing model B

Science.gov (United States)

Bihrle, W., Jr.; Hultberg, R. S.

1979-01-01

Aerodynamic characteristics obtained in a rotational flow environment utilizing a rotary balance located in a spin tunnel are presented in plotted form for a 1/6.5 scale, single engine, high wing, general aviation airplane model. The configurations tested included the basic airplane, various wing leading-edge devices, tail designs, and rudder control settings as well as airplane components. Data are presented without analysis for an angle of attack range of 8 deg to 90 deg and clockwise and counter-clockwise rotations covering an omega b/2V range from 0 to 0.85.

Vortex lift augmentation by suction on a 60 deg swept Gothic wing

Science.gov (United States)

Taylor, A. H.; Jackson, L. R.; Huffman, J. K.

1982-01-01

An experimental investigation was conducted in the Langley high-speed 7- by 10-foot wind tunnel to determine the aerodynamic performance of suction applied near the wing tips above the trailing edge of a 60 deg swept Gothic wing. Moveable suction inlets were symmetrically mounted in the proximity of the trailing edge, and the amount of suction was varied to maximize wing lift. Tests were conducted at Mach 0.15, 0.30, and 0.45, and the angle of attack was varied from -4 to 50 deg. The suction augmentation increases the lift coefficient over the entire range of angle of attack. The lift improvement exceeds the unaugmented wing lift by over 20%. Moreover, the augmented lift exceeds the lift predicted by vortex lattice theory to 30 deg angle of attack. Suction augmentation is postulated to strengthen the vortex system by increasing its velocity and making it more concentrated. This causes the vortex breakdown to be delayed to a higher angle of attack

Determination of the spiral Galaxy structure parameters based on neutral hydrogen radiowave radiation in 21 cm line. 2. Nonlinear theory. 30 deg <= |l| <= 60 deg

International Nuclear Information System (INIS)

Berman, V.G.; Mishurov, Yu.N.

1980-01-01

Gas flow and its density distribution in the Galaxy spiral arm gravitational potential is calculated by means of the nonlinear theory. Line profile of H I emission in 21 cm based on the Galaxy spiral structure models proposed by Lin and Marochnik are constructed for the galactic coordinates 30 deg < or approximately |l| < or approximately 60 deg. It is shown that the conclusion about the possibility of agreement of the Marochnik model with observations made by means of the linear theory is confirmed in the nonlinear theory. In the Marochnik model distributions with R H II regions, CO-clouds, γ-radiation, supernova remnants and so on may also be understood connecting them with variation of gas compression in galactic shock with H radius

Apparent and partial molar volumes of long-chain alkyldimethylbenzylammonium chlorides and bromides in aqueous solutions at T=15 deg. C and T=25 deg. C

International Nuclear Information System (INIS)

Gonzalez-Perez, A.; Ruso, J.M.; Nimo, J.; Rodriguez, J.R.

2003-01-01

Density measurements of dodecyl- (C 12 DBACl), tetradecyl- (C 14 DBACl), hexadecyldimethylbenzylammonium chloride (C 16 DBACl) and of decyl- (C 10 DBABr) and dodecyldimethylbenzylammonium bromide (C 12 DBABr) in aqueous solutions at T=15 deg. C and T=25 deg. C have been carried out. From these results, apparent and partial molar volumes were calculated. Positive deviations from the Debye-Hueckel limiting law provide evidence for limited association at concentrations below the critical micelle concentration. The change of the apparent molar volume upon micellization was calculated. The relevant parameters have been presented in function of the alkyl chain length. Apparent molar volumes of the present compounds in the micellar phase, V phi m , and the change upon micellization, ΔV phi m , have been discussed in terms of temperature and type of counterion

Strain ageing of the 15Kh2MFA steel at 500 and 550 deg C

International Nuclear Information System (INIS)

Maksimovich, G.G.; Azbukin, V.G.; Krylova, R.P.; Tretyak, I.Yu.; Bardachevskaya, T.V.

1978-01-01

The effect of ageing at high temperatures and under high stresses on strength and plasticity of the 15Kh2MFA steel has been studied. The steel was kept at 500 and at 550 deg C for 100, 1000 and 2500 hours without stress and under stress of 0.5 and 0.9 of the long-term strength limit (sigmasub(ls)). Ageing at 500 deg C without stress and under 0.5 sigmasub(ls) changed neither strength nor plasticity of the steel; under 0.9 sigmasub(ls) the strength somewhat decreased. Ageing at 550 deg C for 1000 hours resulted in an appreciable stress drop

Irradiation creep of the martensitic steel no. 1.4914 between 400 deg C and 600 deg C (Mol 5B)

International Nuclear Information System (INIS)

Herschbach, K.; Doser, W.

1983-01-01

The irradiation induced creep of the martensitic steel DIN No. 1.4914 was investigated in the temperature range from 400 to 600 deg C for stresses up to 200 Mpa using the Mol 5B irradiation rig. The results point to a behavior quite different from that observed in the austenitic steels as will be discussed in detail. The creep is thermally activated and non-linearly dependent upon the applied stress. (author)

Low cycle fatigue behaviour of neutron irradiated copper alloys at 250 and 350 deg. C

DEFF Research Database (Denmark)

Singh, B.N.; Stubbins, J.F.; Toft, P.

2000-01-01

V) to influence levels of 1.0 - 1.5 x 1024 n/m2 (E> 1 MeV) at 250 and 350 deg. C. These irradiations were carried out in temperature controlled rigs where the irradiation temperature was monitored and controlledcontinuously throughout the whole irradiation experiment. Both unirradiated and irradiated speciments...

Off-nadir antenna bias correction using Amazon rain forest sigma deg data. [Brazil

Science.gov (United States)

Birrer, I. J.; Bracalente, E. M.; Dome, G. J.; Sweet, J.; Berthold, G.; Moore, R. K. (Principal Investigator)

1981-01-01

The radar response from the Amazon rain forest was studied to determine the suitability of this region for use as a standard target to calibrate a scatterometer like that proposed for the National Ocean Satellite System (NOSS). Backscattering observations made by the SEASAT-1 scatterometer system show the Amazon rain forest to be a homogeneous, azimuthally-isotropic, radar target which is insensitive to polarization. The variation with angle of incidence may be adequately modeled as sigma deg (dB) = alpha theta + beta with typical values for the incidence-angle coefficient from 0.07 dB deg to 0.15 dB/deg. A small diurnal effect occurs, with measurements at sunrise being 0.5 dB to 1 dB higher than the rest of the day. Maximum likelihood estimation algorithms are presented which permit determination of relative bias and true pointing angle for each beam. Specific implementation of these algorithms for the proposed NOSS scatterometer system is also discussed.

Models for Surface Roughness Scattering of Electrons in a 2DEG

International Nuclear Information System (INIS)

Yarar, Z.

2004-01-01

In this work surface roughness scattering of electrons in a two dimensional electron gas (2DEG) formed at heterojunction interfaces is investigated for different auto-correlation tions and potential forms. Gaussian, exponentiaI and lorentsian auto-correlation tions are used to represent surface roughness. Both an infinitely deep triangular potential model and the potential that is found from the numerical solution of Poisson Shrodinger equations self consistently are used as the potential that holds 2DEG at the hetero Interface. Using the wave functions appropriate for the potentials just mentioned and the auto-correlation functions indicated above, the scattering rates due to surface roughness are calculated. The calculations were repeated when the effect of screening is also included for the case of triangular potential

Retrieving SW fluxes from geostationary narrowband radiances for the NASA-CERES SYN1deg product

Science.gov (United States)

Wrenn, F. J., IV; Doelling, D. R.; Liang, L.

2017-12-01

The CERES mission was designed to measure the natural variability of the net TOA flux over long time scales relevant to climate monitoring. To achieve this goal, CERES provides the level-3 SSF1deg, SYN1deg, and EBAF monthly 1° by 1° regional TOA flux. The single satellite (Terra or Aqua) SSF1deg 24-hour shortwave flux is based on one daytime measurements and assumes constant meteorology to model the diurnal change in albedo. To accurately describe regions with a prominent diurnal signal, the SYN1deg Edition4 dataset employs hourly geostationary (GEO) measurements. This improves upon Edition3, which used 3-hourly GEO measurements and with temporal interpolation. The EBAF product combines the temporal stability of the SSF1deg product with the diurnal information from SYN1deg and removes the CERES instrument calibration bias by constraining the net flux balance to the ocean heat storage term. The SYN-1deg product retrieves hourly SW fluxes from GEO measurements. Over regions with large diurnal cycles, such as maritime stratus and land afternoon convective locations, the GEO derived SW fluxes will capture the diurnal flux not observed with Terra or Aqua sun-synchronous satellites. Obtaining fluxes from geostationary satellite radiance is a multistep process. First, most GEO visible imagers lack calibration and must be calibrated to MODIS and VIIRS. Second, the GEO imager visible channel radiances are converted to broadband radiances using empirical and theoretical models. The lack of coincident, collocated, and co-angled GEO and CERES measurements makes building an empirical model difficult. The narrowband to broadband models are a function of surface and cloud conditions, which are difficult to identify due to the inconsistent cloud retrievals between the 16 GEO imagers used in the CERES record. Third, the GEO derived broadband radiances are passed through the CERES angular distribution model (ADM) to convert the radiances to fluxes. Lastly, the GEO derived

A preliminary design and structural analysis on the central column for supporting the full 40 .deg. Sectors at tokamak in pit

International Nuclear Information System (INIS)

Nam, Kyoungo; Park, Hyun Ki; Kim, Dong Jin; Moon, Jaeh Wan; Kim, Byung Seok; Watson, Emma; Shaw, Robert

2012-01-01

The ITER Tokamak machine is composed of nine 40 .deg. sectors shaped of torus. Each 40.deg. sector is made up of one 40 .deg. vacuum vessel (VV), two 20 .deg. toroidal filed coils and associated vacuum vessel thermal shield (VVTS) segments which consist of one inboard and two outboard VVTS. The VV/TFC/VVTS 40 .deg. sectors are sub assembled at assembly building respectively at sector sub assembly tool and then nine sub assembled 40 .deg. sectors are finally assembled at in-pit of Tokamak building. ITER sector assembly tools are the purpose built assembly tools to assemble nine 40 .deg. sectors into the complete ITER Tokamak machine at Tokamak in pit. Based on the design description document, final report prepared by the ITER organization (IO) and tooling requirements, Korea has carried out the conceptual and preliminary design of these assembly tools. Especially, the central column is the main tool, which is composed of some hollow cylinders, to support full nine 40 .deg. sectors at Tokamak in pit. Configuration and structural analysis of the central column are presented

The isothermal section at 500 deg. C of the Gd-Tb-Ga ternary system

International Nuclear Information System (INIS)

Li, J.Q.; Jian, Y.X.; Ao, W.Q.; Zhuang, Y.H.; He, W.

2006-01-01

Phase equilibria in the Gd-Tb-Ga ternary system at 500 deg. C were investigated by X-ray powder diffraction and differential scanning calorimetry. The binary compounds, Gd 5 Ga 3 , Gd 3 Ga 2 , GdGa, GdGa 2 , Tb 5 Ga 3 , TbGa, TbGa 2 and TbGa 3 have been confirmed at 500 deg. C. No ternary compound was found in this system. The isothermal section of this system at 500 deg. C was constructed. It is composed of 7 single-phase regions, 8 two-phase regions and 2 three-phase regions. Four ternary continuous solid solutions (Gd, Tb), (Gd, Tb) 5 Ga 3 , (Gd, Tb)Ga, (Gd, Tb)Ga 2 were formed in this isothermal section. The maximum solid solubilities of Ga in (Gd, Tb) at 500 deg. C is 5.0 at.%. The homogeneity range of (Gd, Tb)Ga 2 is from 20 to 33.3 at.% Ga in Gd-Ga side but limited in Tb-Ga side. The solid solubilities of Ga in the other phases cannot be detected. The Curie temperatures of the Gd 0.6 Tb 0.4-x Ga x alloys increase from 270 to 298 K as x increases from 0 to 0.03

Ge films grown on Si substrates by molecular-beam epitaxy below 450 deg. C

International Nuclear Information System (INIS)

Liu, J.; Kim, H.J.; Hul'ko, O.; Xie, Y.H.; Sahni, S.; Bandaru, P.; Yablonovitch, E.

2004-01-01

Ge thin films are grown on Si(001) substrates by molecular-beam epitaxy at 370 deg. C. The low-temperature epitaxial growth is compatible with the back-end thermal budget of current generation complementary metal-oxide-semiconductor technology, which is restricted to less than 450 deg. C. Reflection high-energy electron diffraction shows that single-crystal Ge thin films with smooth surfaces could be achieved below 450 deg. C. Double-axis x-ray θ/2θ scans also show that the epitaxial Ge films are almost fully strain-relaxed. As expected, cross-sectional transmission electron microscopy shows a network of dislocations at the interface. Hydrogen and oxide desorption techniques are proved to be necessary for improving the quality of the Ge films, which is reflected in improved minority carrier diffusion lengths and exceptionally low leakage currents

Effect of temperatures up to 130 deg C on the responses of TLD 700

Energy Technology Data Exchange (ETDEWEB)

Douglas, J A; Binns, P J [UKAEA Atomic Energy Research Establishment, Harwell. Environmental and Medical Sciences Div.

1984-01-01

The need to measure doses at temperatures up to 130 deg C led to an investigation into the effect of exposure and storage at these temperatures on the response of TLD 700 before and after UV phototransfer. As a preliminary, the delays required during the UV re-estimation process were optimised. The effects of storage and exposure were compared. This was followed by a detailed examination of the effects of storage at temperatures up to 130 deg C. Glow curves were analysed to investigate the rates of growth and decay of the different peaks. The findings for peaks 6 and 7 are compatible with previously reported effects at lower temperatures on peaks 3, 4 and 5. Storage at temperatures of 130 deg C or below for periods up to 28 days does not affect the UV photo-transfer response.

Degradation of PsbO by the Deg Protease HhoA Is Thioredoxin Dependent

OpenAIRE

Roberts, Irma N.; Lam, Xuan Tam; Miranda, Helder; Kieselbach, Thomas; Funk, Christiane

2012-01-01

The widely distributed members of the Deg/HtrA protease family play an important role in the proteolysis of misfolded and damaged proteins. Here we show that the Deg protease rHhoA is able to degrade PsbO, the extrinsic protein of the Photosystem II (PSII) oxygen-evolving complex in Synechocystis sp. PCC 6803 and in spinach. PsbO is known to be stable in its oxidized form, but after reduction by thioredoxin it became a substrate for recombinant HhoA (rHhoA). rHhoA cleaved reduced eukaryotic (...

Exploring a possible origin of a 14 deg y-normal spin tilt at RHIC polarimeter

Energy Technology Data Exchange (ETDEWEB)

Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-06-15

A possible origin of a 14 deg y-normal spin n^→₀ tilt at the polarimeter is in snake angle defects. This possible cause is investigated by scanning the snake axis angle µ, and the spin rotation angle at the snake, φ, in the vicinity of their nominal values.

Giovanni Degli Alessandri: i primi anni del direttorato agli Uffizi fra nuovi e vecchi ruoli

Directory of Open Access Journals (Sweden)

Chiara Pasquinelli

2011-11-01

Full Text Available La figura di Giovanni Degli Alessandri (1765-1830, presidente dell’Accademia di Belle Arti di Firenze e direttore degli Uffizi tra gli anni napoleonici e la Restaurazione di Ferdinando III d’Asburgo-Lorena, è quella di un personaggio chiave nella politica artistica fiorentina, e toscana più in generale. Nel saggio si esaminano i primi anni del suo direttorato alla Galleria, i rapporti con Antonio Canova, il suo ruolo all’interno dell’entourage di Elisa Baciocchi Bonaparte, oltre a considerare alcuni spunti legati al rinnovamento degli Uffizi, nonché la delicata vicenda del passaggio in città di Dominique-Vivant Denon, direttore del Louvre. L’obbiettivo è quello di introdurre elementi di approfondimento relativamente a una figura molto nota ma poco studiata.

Rotary balance data for a typical single-engine general aviation design for an angle of attack range of 8 deg to 90 deg. 1: Low wing model C. [wind tunnel tests

Science.gov (United States)

Mulcay, W. J.; Rose, R. A.

1980-01-01

Aerodynamic characteristics obtained in a helical flow environment utilizing a rotary balance located in the Langley spin tunnel are presented in plotted form for a 1/6 scale, single engine, low wing, general aviation model (model C). The configurations tested included the basic airplane and control deflections, wing leading edge and fuselage modification devices, tail designs and airplane components. Data are presented without analysis for an angle of attack range of 8 deg to 90 deg and clockwise and counter clockwise rotations covering an omega b/2v range from 0 to .9.

An investigation of the aerodynamic characteristics of a 0.00548 scale model (model no. 486) of the space shuttle 146-inch diameter solid rocket booster at angels of attack from 113 deg to 180 deg in the AEDC PWT 4-foot transonic wind tunnel (SA16F)

Science.gov (United States)

Ramsey, P. E.

1976-01-01

An experimental investigation (SA16F) was conducted in the AEDC PWT 4T to determine the entry static stability of a 0.00548 scale space shuttle solid rocket booster (SRB). The primary objective was to improve the definition of the aerodynamic characteristics in the angle of attack range beyond 90 deg in the vicinity of the entry trim point. The SRB scale model consisted of the reentry configuration with all major protuberances. A simulated heat shield around the engine nozzle was also included. Data were obtained for a 60 deg side mounted sting and a straight nose mounted sting. The angle of attack range for the side mounted sting was 113 deg to 147 deg and for the nose mounted sting 152 deg to 187 deg. The Mach number range consisted of 0.4 to 1.2 at roll angles of 0 and 90 deg. The resulting 6-component aerodynamic force data was presented as the variation of coefficients with angle of attack for each Mach number and roll angle.

Solubility of ammonium metavanadate in ammonium carbonate and sodium bicarbonate solutions at 25 deg C

International Nuclear Information System (INIS)

Fedorov, P.I.; Andreev, V.K.; Slotvinskij-Sidak, N.P.

1978-01-01

Solubility at 25 deg C has been studied in the system ammonium metavanadate - sodium bicarbonate - water which is a stable section of the corresponding quaternary mutual system. In the eutonic point the content of ammonium metavanadate is 4.95% and of sodium bicarbonate 12.1%. The crystallization branch of ammonium metavanadate has been studied in the system ammonium metavanadate - ammonium carbonate - water at 25 deg C. Metavanadate solubility attains minimum (0.14%) at ammonium carbonate concentration 2.6%. Three sections have been studied of the quaternary system ammonium - metavanadate - ammonium carbonate - sodium bicarbonate-water at 25 deg C in the crystallization region of ammonium metavanadate at a ratio of sodium bicarbonate to ammonium carbonate 3:1, 1:1, and 1:3. A region of minimum solubility of ammonium metavanadate has been detected (0.1%)

Oxidation-induced embrittlement and structural changes of Zircaloy-4 tubing in steam at 700-1000 deg. C

Energy Technology Data Exchange (ETDEWEB)

Ali, A E; Huessein, A G; El-Sayed, A A; El Banna, O A [Atomic Energy Authority, Cairo (Egypt); El Raghy, S M [Cairo Univ. (Egypt). Faculty of Engineering

1997-02-01

The oxidation-induced embrittlement and structural changes of Zircaloy-4 (KWU-Type) tubing was investigated under light water reactors (LWR) Loss-of-Coolant. Accident conditions (LOCA) in temperature range 700-1000 deg. C. The effect of hydrogen addition to steam was also investigated in the temperature range 800-1000 deg. C. The oxidation-induced embrittlement was found to be a function of both temperature and time. Fractography investigation of oxidized tubing showed a typical brittle fracture in the stabilized-alpha zone. The microhardness measurements revealed that the alpha-Zr is harder than that near the mid-wall position. The oxidation-induced embrittlement at 900 deg. C was found to be higher than at 1000 deg. C. The results also indicated that the addition of 5% by volume hydrogen to steam resulted in an increase in the degree of embrittlement. (author). 22 refs, 9 figs, 3 tabs.

Surface protection of a chromia forming alloy at 1300deg C

International Nuclear Information System (INIS)

Lobb, R.C.; Bennett, M.J.

1990-01-01

Under postulated abnormal (fault) reactor conditions, a rapid temperature transient could occur such that for a short time ( 2 /1-2% CO/300 vpm H 2 O/300 vpm CH 4 , at 1.300deg C has been studied. (orig./MM)

Excimer laser recrystallization of nanocrystalline-Si films deposited by inductively coupled plasma chemical vapour deposition at 150 deg. C

International Nuclear Information System (INIS)

Park, Joong-Hyun; Han, Sang-Myeon; Park, Sang-Geun; Han, Min-Koo; Shin, Moon-Young

2006-01-01

Polycrystalline silicon thin film transistors (poly-Si TFTs) fabricated at low temperature (under 200 deg. C) have been widely investigated for flexible substrate applications such as a transparent plastic substrate. Unlike the conventional TFT process using glass substrate, the maximum process temperature should be kept less than 200 deg. C in order to avoid thermal damage on flexible substrates. We report the characteristics of nanocrystalline silicon (nc-Si) irradiated by an excimer laser. Nc-Si precursors were deposited on various buffer layers by inductively coupled plasma chemical vapour deposition (ICP-CVD) at 150 deg. C. We employed various buffer layers, such as silicon nitride (SiN X ) and silicon dioxide (SiO 2 ), in order to report recrystallization characteristics in connection with a buffer layer of a different thermal conductivity. The dehydrogenation and recrystallization was performed by step-by-step excimer laser annealing (ELA) (XeCl,λ=308 nm) in order to prevent the explosive release of hydrogen atoms. The grain size of the poly-Si film, which was recrystallized on the various buffer layers, was measured by scanning electron microscopy (SEM) at each laser energy density. The process margin of step-by-step ELA employing the SiN X buffer layer is wider than SiO 2 and the maximum grain size slightly increased

Turn down the heat: why a 4 deg. C warmer world must be avoided

International Nuclear Information System (INIS)

Schellnhuber, Hans Joachim; Hare, William; Serdeczny, Olivia; Adams, Sophie; Coumou, Dim; Frieler, Katja; Martin, Maria; Otto, Ilona M.; Perrette, Mahe; Robinson, Alexander; Rocha, Marcia; Schaeffer, Michiel; Schewe, Jacob; Wang, Xiaoxi; Warszawski, Lila; Durand, Francis

2012-11-01

This paper summarizes in French the content of a Report for the World Bank made by the Potsdam Institute for Climate Impact Research and Climate Analytics. This report provides a snapshot of recent scientific literature (about 190 papers) and new analyses of likely impacts and risks that would be associated with a 4 deg. Celsius warming within this century. It is a rigorous attempt to outline a range of risks, focusing on developing countries and especially the poor. A 4 deg. C world would be one of unprecedented heat waves, severe drought, and major floods in many regions, with serious impacts on ecosystems and associated services. But with action, a 4 deg. C world can be avoided and we can likely hold warming below 2 deg. C. This report is not a comprehensive scientific assessment, as will be forthcoming from the Intergovernmental Panel on Climate Change (IPCC) in 2013-14 in its fifth assessment report. It is focused on developing countries, while recognizing that developed countries are also vulnerable and at serious risk of major damages from climate change. A series of recent extreme events worldwide continue to highlight the vulnerability of not only the developing world but even wealthy industrialized countries. No nation will be immune to the impacts of climate change. However, the distribution of impacts is likely to be inherently unequal and tilted against many of the world's poorest regions, which have the least economic, institutional, scientific, and technical capacity to cope and adapt

Sexy DEG/ENaC channels involved in gustatory detection of fruit fly pheromones.

Science.gov (United States)

Pikielny, Claudio W

2012-11-06

Hydrocarbon pheromones on the cuticle of Drosophila melanogaster modulate the complex courtship behavior of males. Recently, three members of the degenerin/epithelial Na+ channel (DEG/ENaC) family of sodium channel subunits, Ppk25, Ppk23, and Ppk29 (also known as Nope), have been shown to function in gustatory perception of courtship-modulating contact pheromones. All three proteins are required for the activation of male courtship by female pheromones. Specific interactions between two of them have been demonstrated in cultured cells, suggesting that, in a subset of cells where they are coexpressed, these three subunits function within a common heterotrimeric DEG/ENaC channel. Such a DEG/ENaC channel may be gated by pheromones, either directly or indirectly, or alternatively may control the excitability of pheromone-sensing cells. In addition, these studies identify taste neurons that respond specifically to courtship-modulating pheromones and mediate their effects on male behavior. Two types of pheromone-sensing taste neurons, F and M cells, have been defined on the basis of their specific response to either female or male pheromones. These reports set the stage for the dissection of the molecular and cellular mechanisms that mediate gustatory detection of contact pheromones.

Elucidating of the microstructure of ZrO2 ceramics with additions of 1200 deg. C heat treated ultrafine MgO powders: Aging at 1420 deg. C

International Nuclear Information System (INIS)

Brito-Chaparro, J.A.; Reyes-Rojas, A.; Bocanegra-Bernal, M.H.; Aguilar-Elguezabal, A.; Echeberria, J.

2007-01-01

The microstructure and phase transformations in the pressureless sintered composite ZrO 2 with additions of 3.11 wt% high purity and ultrafine MgO powder (9.25 mol% Mg-PSZ) heat treated at 1200 deg. C were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction, before and after of eutectoid aging treatment at 1420 deg. C during 4 h. The phases in the as-sintered ceramics were t, c, and m, and was not evident under the experimental conditions of this work, the formation of typical disk-like shape tetragonal precipitates aligned at right angles, meanwhile the microstructure resulting in aged samples was majority monoclinic stable phase showing a banded structure which appear to be twin related. When is used MgO previously heat treated as stabilizer of ZrO 2 , strong differences in SEM microstructures compared to the shown by other investigators in very similar compositions have been found

Mechanical properties of steel fiber reinforced reactive powder concrete following exposure to high temperature reaching 800 deg. C

Energy Technology Data Exchange (ETDEWEB)

Tai, Yuh-Shiou, E-mail: ystai@cc.cma.edu.tw [Department of Civil Engineering, ROC Military Academy, Kaohsiung, Taiwan (China); Pan, Huang-Hsing; Kung, Ying-Nien [Department of Civil Engineering, Kaohsiung University of Applied Sciences, Kaohsiung, Taiwan (China)

2011-07-15

Highlights: > The stress-strain relation of reactive powder concrete after exposure to high temperatures are tested by using displacement control. > Develops regression formulae to estimate the mechanical properties of RPC. > Valuable experimental data have been obtained about RPC with various fiber contents. These data include compressive strength, peak strain and modulus of elasticity. - Abstract: This study investigates the stress-strain relation of RPC in quasi-static loading after an elevated temperature. The cylinder specimens of RPC with {phi} 50 mm x 100 mm are examined at the room temperature and after 200-800 deg. C. Experimental results indicate that the residual compressive strength of RPC after heating from 200-300 deg. C increases more than that at room temperature, but, significantly decreases when the temperature exceeds 300 deg. C. The residual peak strains of RPC also initially increase up to 400-500 deg. C, then decrease gradually beyond 500 deg. C. Meanwhile, Young's modulus diminishes with an increasing temperature. Based on the regression analysis results, this study also develops regression formulae to estimate the mechanical properties of RPC after an elevated temperature, thus providing a valuable reference for industrial applications and design.

Book review, Igiene e Tecnologie degli Alimenti di Origine Animale Giampaolo Colavita (a cura di

Directory of Open Access Journals (Sweden)

Manuel Graziani

2008-09-01

Full Text Available Igiene e Tecnologie degli Alimenti di Origine Animale si avvale del contributo di 33 autori, tutti soci dell’Associazione Italiana Veterinari Igienisti (AIVI, che garantiscono l’appropriata trattazione di una materia estremamente vasta e dinamica. Il manuale nasce da un’iniziativa finalizzata alla realizzazione di un testo che rifletta e possa soddisfare le esigenze didattiche degli insegnamenti di un’ampia serie di materie universitarie: Igiene e Tecnologie degli Alimenti di Origine Animale della Facoltà di Medicina Veterinaria, di Agraria, nei corsi di Scienze e Tecnologie Alimentari, di Scienze e Tecnologie delle Produzioni Animali, nel corso di laurea in Tecniche della Prevenzione nell’ambiente e nei Luoghi di Lavoro, nonché in altri corsi di studio dove si insegnano le discipline relative all’igiene e alla sicurezza degli alimenti.Sono stati trattati gran parte degli alimenti di origine animale, i prodotti a base di carne, il latte e i prodotti derivati, i prodotti della pesca freschi e trasformati, i prodotti dell’alveare, le uova e gli ovoprodotti. Di particolare interesse appare il capitolo riguardante la diagnostica analitica degli alimenti, considerato che le moderne metodologie analitiche risultano fondamentali per affrontare le tematiche legate all’igiene e alla sicurezza alimentare.Il volume ha una finalità prevalentemente didattica ma è comunque rivolto a tutti coloro che operano nel campo dell’Igiene e delle Tecnologie Alimentari. Infatti, visti gli argomenti trattati come le tossinfezioni e le intossicazioni alimentari, la conservazione, il confezionamento e l’etichettatura dei prodotti alimentari, anche i professionisti del settore possono trarre dal testo elementi utili per la loro attività. Per esempio argomenti quali l’analisi del rischio, le attività di audit ed i sistemi di accreditamento e di certificazione sono particolarmente utili per chi opera nelle Aziende Sanitarie Locali e negli Istituti

Solubility of nickel ferrite (NiFe2O4) from 100 to 200 deg. C

International Nuclear Information System (INIS)

Bellefleur, Alexandre; Bachet, Martin; Benezeth, Pascale; Schott, Jacques

2012-09-01

The solubility of nickel ferrite was measured in a Hydrogen-Electrode Concentration Cell (HECC) at temperatures of 100 deg. C, 150 deg. C and 200 deg. C and pH between 4 and 5.25. The experimental solution was composed of HCl and NaCl (0.1 mol.L -1 ). Based on other studies ([1,2]), pure nickel ferrite was experimentally synthesized by calcination of a mixture of hematite Fe 2 O 3 and bunsenite NiO in molten salts at 1000 deg. C for 15 hours in air. The so obtained powder was fully characterized. The Hydrogen-Electrode Concentration cell has been described in [3]. It allowed us to run solubility experiments up to 250 deg. C with an in-situ pH measurement. To avoid reduction of the solid phase to metallic nickel, a hydrogen/argon mixture was used instead of pure hydrogen. Consequently, the equilibration time for the electrodes was longer than with pure hydrogen. Eight samples were taken on a 70 days period. After the experiments, the powder showed no significant XRD evidence of Ni (II) reduction. Nickel concentration was measured by atomic absorption spectroscopy and iron concentration was measured by UV spectroscopy. The protocol has been designed to be able to measure both dissolved Fe (II) and total iron. The nickel solubility of nickel ferrite was slightly lower than the solubility of nickel oxide in close experimental conditions [3]. Dissolved iron was mainly ferrous and the solution was under-saturated relative to both hematite and magnetite. The nickel/iron ratio indicated a non-stoichiometric dissolution. The solubility measurements were compared with equilibrium calculations using the MULTEQ database. [1] Hayashi et al (1980) J. Materials Sci. 15, 1491-1497. [2] Ziemniak et al (2007) J. Physics and Chem. of Solids. 68,10-21. [3] EPRI Report 1003155 (2002). (authors)

Reversal of the ΔdegP Phenotypes by a Novel rpoE Allele of Escherichia coli

Science.gov (United States)

Leiser, Owen P.; Charlson, Emily S.; Gerken, Henri; Misra, Rajeev

2012-01-01

RseA sequesters RpoE (σE) to the inner membrane of Escherichia coli when envelope stress is low. Elevated envelope stress triggers RseA cleavage by the sequential action of two membrane proteases, DegS and RseP, releasing σE to activate an envelope stress reducing pathway. Revertants of a ΔdegP ΔbamB strain, which fails to grow at 37°C due to high envelope stress, harbored mutations in the rseA and rpoE genes. Null and missense rseA mutations constitutively hyper-activated the σE regulon and significantly reduced the major outer membrane protein (OMP) levels. In contrast, a novel rpoE allele, rpoE3, resulting from the partial duplication of the rpoE gene, increased σE levels greater than that seen in the rseA mutant background but did not reduce OMP levels. A σE-dependent RybB::LacZ construct showed only a weak activation of the σE pathway by rpoE3. Despite this, rpoE3 fully reversed the growth and envelope vesiculation phenotypes of ΔdegP. Interestingly, rpoE3 also brought down the modestly activated Cpx envelope stress pathway in the ΔdegP strain to the wild type level, showing the complementary nature of the σE and Cpx pathways. Through employing a labile mutant periplasmic protein, AcrAL222Q, it was determined that the rpoE3 mutation overcomes the ΔdegP phenotypes, in part, by activating a σE-dependent proteolytic pathway. Our data suggest that a reduction in the OMP levels is not intrinsic to the σE-mediated mechanism of lowering envelope stress. They also suggest that under extreme envelope stress, a tight homeostasis loop between RseA and σE may partly be responsible for cell death, and this loop can be broken by mutations that either lower RseA activity or increase σE levels. PMID:22439016

Simulated cosmic microwave background maps at 0.5 deg resolution: Basic results

Science.gov (United States)

Hinshaw, G.; Bennett, C. L.; Kogut, A.

1995-01-01

We have simulated full-sky maps of the cosmic microwave background (CMB) anisotropy expected from cold dark matter (CDM) models at 0.5 deg and 1.0 deg angular resolution. Statistical properties of the maps are presented as a function of sky coverage, angular resolution, and instrument noise, and the implications of these results for observability of the Doppler peak are discussed. The rms fluctuations in a map are not a particularly robust probe of the existence of a Doppler peak; however, a full correlation analysis can provide reasonable sensitivity. We find that sensitivity to the Doppler peak depends primarily on the fraction of sky covered, and only secondarily on the angular resolution and noise level. Color plates of the simulated maps are presented to illustrate the anisotropies.

Comportment of various magnesium alloys in carbon dioxide under pressure, between 400 and 600 deg; Compatibilite de divers alliages de magnesium avec le gaz carbonique sous pression entre 400 et 600 deg

Energy Technology Data Exchange (ETDEWEB)

Darras, R; Baque, P; Chevilliard, C [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

The following materials were studied: nuclear magnesium, two Mg-Zr alloys, a 'Magnox' type alloy, a Mg-Mn alloy and a 'sintered magnesium oxide'. The samples, taken from drawn metals, are suitably polished and given two reproducible surface conditions for purposes of comparison. The tests were carried out in purified carbon dioxide, at pressures of 25 to 60 atmospheres and temperatures from 400 to 600, using special, externally heated stainless steel autoclaves. The duration of the tests is generally more than 1000 hours. The equations of the weight increase curves obtained are of the type: ({delta}p){sup n} = k.t (({delta}p in mg/cm{sup 2} and t in hours), the index n being around 2, at least up to 500 deg. C. Referring to results obtained previously in the case of certain of these materials exposed to carbon dioxide at atmospheric pressure and at 15 atmospheres, it appears that: 1) for given material: - at a given pressure, oxidation increases with temperature, - at a given temperature oxidation increases with pressure, - under the same temperature and pressure conditions, the results vary little according to the two surface states studied; 2) Mg-Zr alloys show better oxidation resistance than non-alloyed magnesium; 3) The alloy magnox shows up much less favourably in carbon dioxide than in air, compared with the other alloys. Generally speaking, the oxidation curves tending towards a threshold after a certain exposure time, all the alloys considered appear to show a satisfactory compatibility with carbon dioxide up to a temperature around 500 deg. C, under the working conditions defined here; above 500, under differences appear between various alloys, but the sublimation phenomena interfere with those of oxidation, with the result that a classification of the various materials can only be based on their resultant. (author) [French] Les materiaux etudies comprennent: le magnesium nucleaire, deux alliages Mg-Zr, un alliage du type 'Magnox', un alliage Mg-Mn et un

Oxidation in air of two refractory alloys (Nicral D and Hastelloy X) at 900 and 1100 deg. C

International Nuclear Information System (INIS)

Sannier, J.; Dominget, R.; Darras, R.

1960-01-01

The oxidation in air of two refractory alloys (Nicral D and Hastelloy X) has been studied at 900 and 1100 deg. C, by means of recording thermo-balances and microscopic cross section examination. At 900 deg. C, the surface oxidation rates of the two alloys are quite similar, but at 1100 deg. C the alloy Nicral D oxidizes faster than the alloy Hastelloy X. On the other hand, after heating at 1100 deg. C for 150 hours, Nicral D shows both intergranular oxidation and a small amount of internal oxidation, whereas Hastelloy X is especially subject to internal oxidation. In addition, two descaling methods were compared: an electrolytic method, in a sodium hydroxide-sodium carbonate bath, and a chemical method using a sodium nitrate-sodium peroxide bath; the latter appears suitable only for Hastelloy X. Reprint of a paper published in Journal of nuclear materials, 3, p. 213-225, 1959 [fr

Aging between 300 and 450 deg C of wrought martensitic 13-17 wt-%Cr stainless steels

International Nuclear Information System (INIS)

Yrieix, B.; Guttmann, M.

1993-06-01

Martensitic stainless steels containing 13-17 wt-% Cr, some also containing nickel and some having precipitation hardening additions, have been aged between 300 and 450 deg C for times up to 30 000 h. For all the steels examined, the aging response takes the form of an increase of strength and hardness, correlated with embrittlement. The rate and intensity of aging increase with increasing chromium and molybdenum concentrations. In addition, two steels exhibit some temper embrittlement on long term aging at 400 deg C; such embrittlement of these materials is not expected in service at temperatures up to 300 deg C. A general method of prediction of the mechanical properties of these steels as a function of aging conditions is proposed. (authors). 11 refs., 17 figs., 7 tabs

BD-22deg3467, a DAO-type Star Exciting the Nebula Abell 35

Science.gov (United States)

Ziegler, M.; Rauch, T.; Werner, K.; Koppen, J.; Kruk, J. W.

2013-01-01

Spectral analyses of hot, compact stars with non-local thermodynamical equilibrium (NLTE) model-atmosphere techniques allow the precise determination of photospheric parameters such as the effective temperature (T(sub eff)), the surface gravity (log g), and the chemical composition. The derived photospheric metal abundances are crucial constraints for stellar evolutionary theory. Aims. Previous spectral analyses of the exciting star of the nebula A35, BD-22deg3467, were based on He+C+N+O+Si+Fe models only. For our analysis, we use state-of-the-art fully metal-line blanketed NLTE model atmospheres that consider opacities of 23 elements from hydrogen to nickel. We aim to identify all observed lines in the ultraviolet (UV) spectrum of BD-22deg3467 and to determine the abundances of the respective species precisely. Methods. For the analysis of high-resolution and high signal-to-noise ratio (S/N) far-ultraviolet (FUSE) and UV (HST/STIS) observations, we combined stellar-atmosphere models and interstellar line-absorption models to fully reproduce the entire observed UV spectrum. Results. The best agreement with the UV observation of BD-22deg3467 is achieved at T(sub eff) = 80 +/- 10 kK and log g = 7.2 +/- 0.3. While T(sub eff) of previous analyses is verified, log g is significantly lower. We re-analyzed lines of silicon and iron (1/100 and about solar abundances, respectively) and for the first time in this star identified argon, chromium, manganese, cobalt, and nickel and determined abundances of 12, 70, 35, 150, and 5 times solar, respectively. Our results partially agree with predictions of diffusion models for DA-type white dwarfs. A combination of photospheric and interstellar line-absorption models reproduces more than 90% of the observed absorption features. The stellar mass is M approx. 0.48 Solar Mass. Conclusions. BD.22.3467 may not have been massive enough to ascend the asymptotic giant branch and may have evolved directly from the extended horizontal branch

Comparison of the corrosion behavior of austenitic and ferritic/martensitic steels exposed to static liquid Pb-Bi at 450 and 550 deg. C

International Nuclear Information System (INIS)

Kurata, Y.; Futakawa, M.; Saito, S.

2005-01-01

Static corrosion tests of various steels were conducted in oxygen-saturated liquid Pb-Bi eutectic at 450 deg. C and 550 deg. C for 3000 h to study the effects of temperature and alloying elements on corrosion behavior in liquid Pb-Bi. Corrosion depth decreases at 450 deg. C with increasing Cr content in steels regardless of ferritic/martensitic steels or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450 deg. C. Corrosion depth of ferritic/martensitic steels also decreases at 550 deg. C with increasing Cr content in steels whereas corrosion depth of austenitic steels, JPCA and 316SS becomes larger due to ferritization caused by dissolution of Ni at 550 deg. C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550 deg. C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr

Crystal structure of Na3Sc2(PO4)3 at 60 deg C

International Nuclear Information System (INIS)

Lazoryak, B.I.; Kalinin, V.B.; Stefanovich, S.Yu.; Efremov, V.A.

1980-01-01

The structure of the ferroelectric phase of Na 3 Sc 2 (PO 4 ) 3 compound was studied. Na 3 Sc 2 (PO 4 ) 3 monocrystal heated by a jet of warm N 2 was investigated at 60 deg C. The rhombohedron modification was determined: a=8.927(3), c=22.34(4) A, Z=6, space group R anti 3c. Interatomic distances and inner angles of polyhedrons in Na 3 Sc 2 (PO 4 ) 3 structure were determined

Modification of strain and 2DEG density induced by wafer bending of AlGaN/GaN heterostructure: Influence of edges caused by processing

Directory of Open Access Journals (Sweden)

Ashu Wang

2018-03-01

Full Text Available Due to the piezoelectricity, the density of 2DEG (NS formed in the AlGaN/GaN heterostructure can be altered when it is deformed externally, which may be exploited to develop pressure sensors and to enhance the performance of power devices by stress engineering based on the heterostructure. In this paper, a 3D electro-mechanical simulation is presented to study how the induced strains and NS for the AlGaN/GaN wafer under bending exerted uniaxial stress are influenced by the edges caused by processing: the fabrication of the mesa used for isolation, the ohmic contact metal, the gate metal, and the passivation. Results show that the influences are dependent on distance between the edges, depth of the edges, and direction of the exerted uniaxial stress.

Temperature dependence of the surface energy of mercury from 0 to 250 deg. C

CERN Document Server

Halas, S

2002-01-01

The surface energy (SE) for mercury was calculated on the basis of the free electron model in which the electron density parameter, r sub s , for bulk electrons was calculated from the density of mercury while the electron density parameter for surface electrons, r sub s sub s , was assumed to be higher by a factor that is linearly dependent on temperature. Ideal agreement of calculated SE values with experimental data was attained for the temperatures 0-250 deg. C assuming that r sub s sub s = r sub s x 1.0021 sup T sup / sup 1 sup 0 sup 0 deg. C. (letter to the editor)

Measurements of anisotropy in the cosmic microwave background radiation at 0.5 deg angular scales near the star gamma ursae minoris

Science.gov (United States)

Devlin, M. J.; Clapp, A. C.; Gundersen, J. O.; Hagmann, C. A.; Hristov, V. V.; Lange, A. E.; Lim, M. A.; Lubin, P. M.; Mauskopf, P. D.; Meinhold, P. R.

1994-01-01

We present results from a four-frequency observation of a 6 deg x 0.6 deg strip of the sky centered near the star Gamma Ursae Minoris (GUM) during the fourth flight of the Millimeter-wave Anistropy experiment(MAX). The observation was made with a 1.4 deg peak-to-peak sinusoidal chop in all bands. The FWHM beam sizes were 0.55 deg +/- 0.05 deg at 3.5 per cm and 0.75 deg +/- 0.05 deg at 6, 9, and 14 per cm. During this observation significant correlated structure was observed at 3.5, 6 and 9 per cm with amplitudes similar to those observed in the GUM region during the second and third fligts of MAX. The frequency spectrum is consistent with cosmic microwave background (CMB) and inconsistent with thermal emission from interstellar dust. The extrapolated amplitudes of synchrotron and free-free emission are too small to account for the amplitude of the observed structure, If all of the structure is attributed to CMB anisotropy with a Gaussian autocorrelation function and a coherence angle of 25 min, then the most probable values of delta T/T(sub CMB) in the 3.5, 6 and 9 per cm bads are (4.3 +2.7/-1.6) x 10(exp -5), 2.8 (+4.3/-1/1) x 10(exp -5), and 3.5 (+3.0/-1.6) x 10(exp -5) (95% confidence upper and lower limits), respectively.

Crystallography of [0 1 1]/54.7 deg. lath boundary and cementite in tempered 0.2C steel

International Nuclear Information System (INIS)

Wei Fugao; Tsuzaki, Kaneaki

2005-01-01

The crystallographic structures of the [0 1 1]/54.7 deg. lath boundary and the intralath and interlath cementite precipitates in a 0.2C steel tempered at 400 deg C have been observed by high resolution transmission electron microscopy and discussed in terms of the O-lattice model. The [0 1 1]/54.7 deg lath boundary which is composed of one Kurdjumov-Sachs variant (α1) and one Nishiyama-Wasserman variant (α2) is likely to facet on the (0 12 7) α1 //(5 19 14) α2 irrational plane. The O-lattice analysis indicated that the facet coincides with a plane with a high density of O-points. Intralath cementite obeys the Isaichev orientation relationship (OR) with ferrite and has a habit plane of (1 0 1) θ //(1 2 1) α . Interlath cementite precipitating on the [0 1 1]/54.7 deg boundary maintains a strict Bagaryatskii OR with the ferrite on one side of the boundary and has a (1 0 0) θ habit plane

Interdiffusion between U-Mo alloys and Al or Al alloys at 340 deg. C. Irradiation plan

International Nuclear Information System (INIS)

Fortis, A.M.; Mirandou, M.; Ortiz, M.; Balart, S.; Denis, A.; Moglioni, A.; Cabot, P.

2005-01-01

Out of reactor interdiffusion experiments between U-Mo alloys and Al alloys made close to fuel operation temperature are needed to validate the results obtained above 500 deg. C. A study of interdiffusion between U-Mo and Al or Al alloys, out and in reactor, has been initiated. The objective is to characterize the interdiffusion layer around 250 deg. C and study the influence of neutron irradiation. Irradiation experiments will be performed in the Argentine RA3 reactor and chemical diffusion couples will be fabricated by Friction Stir Welding (FSW) technique. In this work out-of-pile diffusion experiments performed at 340 deg. C are presented. Friction Stir Welding (FSW) was used to fabricate some of the samples. One of the results is the presence of Si, in the interaction layer, coming from the Al alloy. This is promising in the sense that the absence of Al rich phases may also be expected at low temperature. (author)

Theoretical Studies of Aqueous Systems above 25 deg C. 2. The Iron - Water System

Energy Technology Data Exchange (ETDEWEB)

Lewis, Derek

1971-09-15

A theoretical study of the iron-water system at elevated temperatures is reported. Values for the equilibrium constants for the principle reactions in the system up to 374 deg C, obtained by a method described previously, are given and equilibrium diagrams are presented that illustrate the results for 50, 150, 250 and 350 deg C. The results indicate that, among other things, the most important metal-bearing ions in the iron-water system at elevated temperatures are Fe(OH){sub 2}+, Fe(OH)+ and HFeO{sub 2}- The conditions for the stability of solid iron oxides are also examined. Finally, some limitations of the thermodynamic approach to corrosion problems are discussed briefly

Design of UHECR telescope with 1 arcmin resolution and 50 deg. field of view

CERN Document Server

Sasaki, M; Asaoka, Y

2002-01-01

A new telescope design based on Baker-Nunn optics is proposed for observation of ultra-high-energy cosmic rays (UHECRs). The optical system has an image resolution better than 0.02 deg. within a wide field of view of 50 deg. angular diameter. When combined with a high-quality imaging device, the proposed design enables the directions of UHECRs and high-energy neutrinos to be determined with an accuracy better than 1 arcmin. The outstanding resolution of this telescope allows charge-separated cosmic-rays to be resolved and the source to be determined accurately. This marked improvement in angular resolution will allow the multi-wavelength and 'multi-particle' observations of astronomical objects through collaboration with established astronomical observations.

Investigation on structural integrity of graphite component during high temperature 950degC continuous operation of HTTR

International Nuclear Information System (INIS)

Sumita, Junya; Shimazaki, Yosuke; Shibata, Taiju

2014-01-01

Graphite material is used for internal structures in high temperature gas-cooled reactor. The core components and graphite core support structures are so designed as to maintain the structural integrity to keep core cooling capability. To confirm that the core components and graphite core support structures satisfy the design requirements, the temperatures of the reactor internals are measured during the reactor operation. Surveillance test of graphite specimens and in-service inspection using TV camera are planned in conjunction with the refueling. This paper describes the evaluation results of the integrity of the core components and graphite core support structures during the high temperature 950degC continuous operation, a high temperature continuous operation with reactor outlet temperature of 950degC for 50 days, in high temperature engineering test reactor. The design requirements of the core components and graphite core support structures were satisfied during the high temperature 950degC continuous operation. The dimensional change of graphite which directly influences the temperature of coolant was estimated considering the temperature profiles of fuel block. The magnitude of irradiation-induced dimensional change considering temperature profiles was about 1.2 times larger than that under constant irradiation temperature of 1000degC. In addition, the programs of surveillance test and ISI using TV camera were introduced. (author)

3.55 GeV/c Kp elastic scattering near 180 deg; Diffusion elastique des K de 3.55 GeV/C par les protons, au voisinage de 180 deg

Energy Technology Data Exchange (ETDEWEB)

Duflo, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Backward elastic K{sup +}p and K{sup -}p scattering has been measured in the angular interval 168 deg. < {theta}.c.m. < 177 deg. The experimental apparatus included optical spark chambers to measure the three prongs of the event scattering, a set of scintillation counters and Cerenkov counters to select events ant trigger chambers, and a magnet to determine the moment of the recoil proton. 106000 photographs was taken. Of these, 22 satisfied all requirements as elastic K{sup +}p scattering events. No event was found satisfy the kinematical criteria for K{sup -}p elastic scattering. The correspondent values of differential cross sections are: (d{sigma}/d{omega})K{sup +}p {yields} pK{sup +} = 17 {+-} 4 {mu}b/ster. (d{sigma}/d{omega})K{sup -}p {yields} pK{sup -} {<=} 0.6 {mu}b/ster. Contaminations by {pi}p backward scattering, and inelastic scattering were estimated. Elastic scattering K{sup +}p exhibits a backward peak. A reasonably satisfactory interpretation of our results is obtained by exchange models. There is, in fact, no definitely established particles which could intermediate the Kp{sup -} {yields} pK{sup -} process in exchange cannel. That is in good agreement with our small value of K{sup -}p backward elastic scattering cross section. Our results lend support to the conclusions of the interference model developed by Barger and Cline for the {pi}p backward scattering, and to qualitative previsions of the Quark models. (author) [French] La diffusion elastique en arriere des K{sup +} et K{sup -} par les protons a ete mesuree dans l'intervalle angulaire 168 deg. < {theta}cm < 177 deg. Le dispositif experimental comprenait des chambres a etincelles 'optiques' pour mesurer les trois trajectoires de l'evenement diffuse, un ensemble de compteurs a scintillations et de compteurs Cerenkov pour selectionner les evenements et declencher les chambres, et un aimant pour determiner le moment du proton de recul. 106000 photographies ont ete prises, dont 22 ont satisfait a

3.55 GeV/c Kp elastic scattering near 180 deg; Diffusion elastique des K de 3.55 GeV/C par les protons, au voisinage de 180 deg

Energy Technology Data Exchange (ETDEWEB)

Duflo, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Backward elastic K{sup +}p and K{sup -}p scattering has been measured in the angular interval 168 deg. < {theta}.c.m. < 177 deg. The experimental apparatus included optical spark chambers to measure the three prongs of the event scattering, a set of scintillation counters and Cerenkov counters to select events ant trigger chambers, and a magnet to determine the moment of the recoil proton. 106000 photographs was taken. Of these, 22 satisfied all requirements as elastic K{sup +}p scattering events. No event was found satisfy the kinematical criteria for K{sup -}p elastic scattering. The correspondent values of differential cross sections are: (d{sigma}/d{omega})K{sup +}p {yields} pK{sup +} = 17 {+-} 4 {mu}b/ster. (d{sigma}/d{omega})K{sup -}p {yields} pK{sup -} {<=} 0.6 {mu}b/ster. Contaminations by {pi}p backward scattering, and inelastic scattering were estimated. Elastic scattering K{sup +}p exhibits a backward peak. A reasonably satisfactory interpretation of our results is obtained by exchange models. There is, in fact, no definitely established particles which could intermediate the Kp{sup -} {yields} pK{sup -} process in exchange cannel. That is in good agreement with our small value of K{sup -}p backward elastic scattering cross section. Our results lend support to the conclusions of the interference model developed by Barger and Cline for the {pi}p backward scattering, and to qualitative previsions of the Quark models. (author) [French] La diffusion elastique en arriere des K{sup +} et K{sup -} par les protons a ete mesuree dans l'intervalle angulaire 168 deg. < {theta}cm < 177 deg. Le dispositif experimental comprenait des chambres a etincelles 'optiques' pour mesurer les trois trajectoires de l'evenement diffuse, un ensemble de compteurs a scintillations et de compteurs Cerenkov pour selectionner les evenements et declencher les chambres, et un aimant pour determiner le moment du proton de recul. 106000 photographies ont ete prises

Forced Rolling Oscillation of a 65 deg-Delta Wing in Transonic Vortex-Breakdown Flow

Science.gov (United States)

Menzies, Margaret A.; Kandil, Osama A.; Kandil, Hamdy A.

1996-01-01

Unsteady, transonic, vortex dominated flow over a 65 deg. sharp-edged, cropped-delta wing of zero thickness undergoing forced rolling oscillations is investigated computationally. The wing angle of attack is 20 deg. and the free stream Mach number and Reynolds number are 0.85 and 3.23 x 10(exp 6), respectively. The initial condition of the flow is characterized by a transverse terminating shock which induces vortex breakdown of the leading edge vortex cores. The computational investigation uses the time accurate solution of the laminar, unsteady, compressible, full Navier-Stokes equations with the implicit, upwind, Roe flux difference splitting, finite-volume scheme. While the maximum roll amplitude is kept constant at 4.0 deg., both Reynolds number and roll frequency are varied covering three cases of forced sinusoidal rolling. First, the Reynolds number is held at 3.23 x 10(exp 6) and the wing is forced to oscillate in roll around the axis of geometric symmetry at a reduced frequency of 2(pi). Second, the Reynolds number is reduced to 0.5 x 10(exp 6) to observe the effects of added viscosity on the vortex breakdown. Third, with the Reynolds number held at 0.5 x 10(exp 6), the roll frequency is reduced to 1(pi) to complete the study.

Study of plastic deformation peculiarities in CdS single crystals within the temperature range of 25 to 300 deg C

International Nuclear Information System (INIS)

Bulatova, T.M.

1990-01-01

By the method of stress relaxation dependences of platic deformation rate on effective strain in CdS monocrystals for the temperatures of 25-300 deg C both in the darkness and in the light are obtained. In the range of the temperatures up to 150 deg C deformation activation energy is determined, which correlates with the value of point defect diffusion activation energy in the crystal. Anomalous temperature dependence of plastic deformation rate, i.e. its decrease with the temperature increase in the range of 150-300 deg C is detected

Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 8 deg to 90 deg. 1: Influence of airplane components for model D. [Langley spin tunnel tests

Science.gov (United States)

Ralston, J.

1983-01-01

The influence of airplane components, as well as wing location and tail length, on the rotational flow aerodynamics is discussed for a 1/6 scale general aviation airplane model. The airplane was tested in a built-up fashion (i.e., body, body-wing, body-wing-vertical, etc.) in the presence of two wing locations and two body lengths. Data were measured, using a rotary balance, over an angle-of-attack range of 8 deg to 90 deg, and for clockwise and counter-clockwise rotations covering an omega b/2V range of 0 to 0.9.

Islam, rappresentanza degli interessi religiosi e diritto comune europeo *

Directory of Open Access Journals (Sweden)

Gianfranco Macrì

2011-03-01

Full Text Available Contributo destinato alla pubblicazione negli Atti del Convegno: Europa e Islam. Ridiscutere i fondamenti per la disciplina delle libertà religiose, svoltosi a Salerno il 3 dicembre 2007. SOMMARIO: Premessa - 1. La società «reticolare» europea: sistema di governance e valori unificanti - 2. Europa e fenomeno religioso - 3. La sostanza del Trattato di Lisbona e il ruolo delle organizzazioni religiose - 4. Il dibattito interno all’Islam europeo - 5. La Carta dei musulmani d’Europa - 6. La rappresentanza degli interessi religiosi dell’Islam in Europa - Conclusioni.

Boric acid - trilon B (glycine, acetylurea) - water systems at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Rodionov, N.S.; Molodkin, A.K.; Fedorov, Yu.A.; Tsekhanskij, R.S.

1985-01-01

Boric acid-trilon B (glycine, acetylurea)-water systems are studied at 25 deg C by the methods of isothermal solubility densi- and refractometry. It is ascertained that all of them are of a simple eutonic type with a small salting-out effect of organic components on boric acid

Boric acid - trilon B (glycine, acetylurea) - water systems at 25 deg C

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Rodionov, N S; Molodkin, A K; Fedorov, Yu A; Tsekhanskij, R S

1985-07-01

Boric acid-trilon B (glycine, acetylurea)-water systems are studied at 25 deg C by the methods of isothermal solubility densi- and refractometry. It is ascertained that all of them are of a simple eutonic type with a small salting-out effect of organic components on boric acid.

Systems of amonium polyborates - monoammonium phosphate -water at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Sadetdinov, Sh.V.; Polenov, A.D.; Mikhajlov, V.I.

1992-01-01

It is established by solubility and refractometry methods at 25 deg C that systems of ammonium tetraborate (pentaborate) monoammonium phosphate-water refer to sumple eutonic type. The ammonium borates and monoammoniumphosphate exert salting effect over each other. It is found that phosphate borate compositions on the basis of ammonium salts are characterized by lower inhibitor properties as compared to sodium salts

Sodium nitrate-cerium nitrate-water ternary system at 25 deg C

International Nuclear Information System (INIS)

Fedorenko, T.P.; Onishchenko, M.K.

1978-01-01

Solubility isotherm of sodium nitrate-cerium nitrate-water system at 25 deg C consists of three crystallization branches of initial salts and double compound of the composition 2NaNO 3 xCe(NO 3 ) 3 x2H 2 O. Sodium nitrate introduced in the solution strengthens complexing. Physico-chemical characteristics are in a good agreement with solubility curve

A Deg-protease family protein in marine Synechococcus is involved in outer membrane protein organization

Directory of Open Access Journals (Sweden)

Rhona Kayra Stuart

2014-06-01

Full Text Available Deg-family proteases are a periplasm-associated group of proteins that are known to be involved in envelope stress responses and are found in most microorganisms. Orthologous genes SYNW2176 (in strain WH8102 and sync_2523 (strain CC9311 are predicted members of the Deg-protease family and are among the few genes induced by copper stress in both open ocean and coastal marine Synechococcus strains. In contrast to the lack of a phenotype in a similar knockout in Synechocystis PCC6803, a SYNW2176 knockout mutant in strain WH8102 was much more resistant to copper than the wild-type. The mutant also exhibited a significantly altered outer membrane protein composition which may contribute to copper resistance, longer lag phase after transfer, low-level consistent alkaline phosphatase activity, and an inability to induce high alkaline phosphatase activity in response to phosphate stress. This phenotype suggests a protein-quality-control role for SYNW2176, the absence of which leads to a constitutively activated stress response. Deg-protease family proteins in this ecologically important cyanobacterial group thus help to determine outer membrane responses to both nutrients and toxins.

Charge transport in 2DEG/s-wave superconductor junction with Dresselhaus-type spin-orbit coupling

International Nuclear Information System (INIS)

Sawa, Y.; Yokoyama, T.; Tanaka, Y.

2007-01-01

We study spin-dependent charge transport in superconducting junctions. We consider ballistic two-dimensional electron gas (2DEG)/s-wave superconductor junctions with Dresselhaus-type spin-orbit coupling (DSOC). We calculate the conductance normalized by that in the normal state of superconductor in order to study the effect of DSOC in 2DEG on conductance, changing the height of insulating barrier. We find the DSOC suppresses the conductance for low insulating barrier, while it can slightly enhance the conductance for high insulating barrier. It has a reentrant dependence on DSOC for middle strength insulating barrier. The effect of DSOC is weaken as the insulating barrier becomes high

Solar process for cold production at low temperature (-28 deg) by solid-gas sorption; Procede solaire de production de froid basse temperature (-28 deg) par sorption solide-gaz

Energy Technology Data Exchange (ETDEWEB)

Le Pierres, N.

2005-09-15

The aim of this work is the design and experimentation of a thermochemical process for cold production purpose at -28 deg. C using low grade heat (70 deg. C) supplied by flat plate solar collectors. An exergetic analysis of the thermo-chemical dipole and of ideal thermodynamic cycles led to the definition of an original solar process. This process involves two cascaded cycles functioning in parallel. The cycle is discontinuous and presents a day phase of heating and regeneration and a night phase of cold production. A dynamic simulation allowed the study of its functioning depending on the weather conditions and on the dimensions of the process. A prototype covering the needs of a cold chamber loosing 40 W of cold continuously was built and tested in real conditions in Perpignan. It demonstrated the feasibility of this innovative concept and validated the hypothesis used to develop the model. A study of the process functioning was lead by simulation in different meteorological conditions and for different heat sources (solar, geothermal or industrial waste). It showed the potentialities of the concept. (author)

Behavior of steels in flowing liquid PbBi eutectic alloy at 420-600 deg. C after 4000-7200 h

International Nuclear Information System (INIS)

Mueller, G.; Heinzel, A.; Konys, J.; Schumacher, G.; Weisenburger, A.; Zimmermann, F.; Engelko, V.; Rusanov, A.; Markov, V.

2004-01-01

This paper presents the results of steel exposure up to 7200 h in flowing LBE at elevated temperatures and is a follow-up paper of that with results of an exposure of up to 2000 h. The examined AISI 316 L, 1.4970 austenitic and MANET 10Cr martensitic steels are suitable as a structural material in LBE (liquid eutectic Pb 45 Bi 55 ) up to 550 deg. C, if 10 -6 wt% of oxygen is dissolved in the LBE. The martensitic steel develops a thick magnetite and spinel layer while the austenites have thin spinel surface layers at 420 deg. C and thick oxide scales like the martensitic steel at 550 deg. C. The oxide scales protect the steels from dissolution attack by LBE during the whole test period of 7200 h. Oxide scales that spall off are replaced by new protective ones. At 600 deg. C severe attack occurs already after 2000 and 4000 h of exposure. Steels with 8-15 wt% Al alloyed into the surface suffer no corrosion attack at all experimental temperatures and exposure times

Neutron capture in the 1.15-keV resonance of /sup 56/Fe using Moxon-Rae detectors

International Nuclear Information System (INIS)

Corvi, F.; Bastian, C.; Wisshak, K.

1986-01-01

The capture area in the 1.15-keV neutron resonance of /sup 56/Fe was measured with Moxon-Rae detectors with converters of bismuth, bismuth-graphite, and graphite. The data were normalized to gold capture at 4.91 eV using the saturated resonance method. Two separate measurements were performed: the first with the detector axis at 120 deg with respect to the neutron beam direction and the second with the axis at 90 deg. The average of the results over the three detectors is gΓ/sub n/Γγ/sub / Γ=(64.9 + .2.4) MeV for the 120-deg run and gΓn/Γγ/Γ=(63.5 + .2.1) MeV for the 90-deg run. These values are 14 to 16% larger than the corresponding one from transmission data. No reason is found for such a discrepancy

Performance of MHD coatings in flowing Li at 700 deg

International Nuclear Information System (INIS)

Pint, B.; Pawel, S.J.; Howell, M.; Moser, J.L.; Garner, G.W.; Santella, M.L.; Tortorelli, P.F.; Di Stefano, J.R.

2007-01-01

Full text of publication follows: A thermal convection loop was constructed from V-4Cr-4Ti tubing and operated in vacuum at a maximum Li temperature of 700 deg. C for ∼1000 h.. Due to slow Li flow (∼1 cm/s) in the loop, the temperature gradient was ∼340 deg. C. Specimens in the hot and cold legs of the loop included V-4Cr-4Ti spacers, tensile specimens (SS-3 type) and coupons coated by physical vapor deposition with yttria and over coated with unalloyed vanadium. Based on prior work, the multi-layer electrically-insulating coatings were developed to reduce the magneto hydrodynamic (MHD) force expected in the first wall of a lithium cooled blanket in a magnetic confinement fusion reactor. Characterization of the specimens after exposure will include: (1) mass change and chemistry change as a function of location in the temperature gradient, (2) the effect of Li exposure on the tensile properties of V-4Cr-4Ti and (3) characterization of the properties and microstructure of the coatings after exposure. Of particular interest will be the coating resistivity after exposure and any degradation of the thin (∼10 μm) vanadium overlayer. Chemistry of the Li before and after the experiment will be compared in order to assess any mass transfer effects. (authors)

Top-gate microcrystalline silicon TFTs processed at low temperature (<200 deg. C)

International Nuclear Information System (INIS)

Saboundji, A.; Coulon, N.; Gorin, A.; Lhermite, H.; Mohammed-Brahim, T.; Fonrodona, M.; Bertomeu, J.; Andreu, J.

2005-01-01

N-type as well P-type top-gate microcrystalline silicon thin film transistors (TFTs) are fabricated on glass substrates at a maximum temperature of 200 deg. C. The active layer is an undoped μc-Si film, 200 nm thick, deposited by Hot-Wire Chemical Vapor. The drain and source regions are highly phosphorus (N-type TFTs) or boron (P-type TFTs)-doped μc-films deposited by HW-CVD. The gate insulator is a silicon dioxide film deposited by RF sputtering. Al-SiO 2 -N type c-Si structures using this insulator present low flat-band voltage,-0.2 V, and low density of states at the interface D it =6.4x10 10 eV -1 cm -2 . High field effect mobility, 25 cm 2 /V s for electrons and 1.1 cm 2 /V s for holes, is obtained. These values are very high, particularly the hole mobility that was never reached previously

Creep crack growth in a reactor pressure vessel steel at 360 deg C

Energy Technology Data Exchange (ETDEWEB)

Wu, Rui; Seitisleam, F; Sandstroem, R [Swedish Institute for Metals Research, Stockholm (Sweden)

1999-12-31

Plain creep (PC) and creep crack growth (CCG) tests at 360 deg C and post metallography were carried out on a low alloy reactor pressure vessel steel (ASTM A508 class 2) with different microstructures. Lives for the CCG tests were shorter than those for the PC tests and this is more pronounced for simulated heat affected zone microstructure than for the parent metal at longer lives. For the CCG tests, after initiation, the cracks grew constantly and intergranularly before they accelerated to approach rupture. The creep crack growth rate is well described by C*. The relations between reference stress, failure time and steady crack growth rate are presented for the CCG tests. It is demonstrated that the failure stress due to CCG is considerably lower than the yield stress at 360 deg C. Consequently, the CCG will control the static strength of a reactor vessel. (orig.) 17 refs.

Creep crack growth in a reactor pressure vessel steel at 360 deg C

Energy Technology Data Exchange (ETDEWEB)

Rui Wu; Seitisleam, F.; Sandstroem, R. [Swedish Institute for Metals Research, Stockholm (Sweden)

1998-12-31

Plain creep (PC) and creep crack growth (CCG) tests at 360 deg C and post metallography were carried out on a low alloy reactor pressure vessel steel (ASTM A508 class 2) with different microstructures. Lives for the CCG tests were shorter than those for the PC tests and this is more pronounced for simulated heat affected zone microstructure than for the parent metal at longer lives. For the CCG tests, after initiation, the cracks grew constantly and intergranularly before they accelerated to approach rupture. The creep crack growth rate is well described by C*. The relations between reference stress, failure time and steady crack growth rate are presented for the CCG tests. It is demonstrated that the failure stress due to CCG is considerably lower than the yield stress at 360 deg C. Consequently, the CCG will control the static strength of a reactor vessel. (orig.) 17 refs.

The Codice digitale degli archivi veronesi. A research instrument

Directory of Open Access Journals (Sweden)

Andrea Brugnoli

2014-04-01

Full Text Available The Codice digitale degli archivi veronesi (Verona’s archives digital code ‹http://cdavr.dtesis.univr.it› makes available online the digital reproductions of the documents produced by corporate bodies and family of Verona between the eighth and twelfth century. The framework of the site reflects the current organisation of the archives. A brief description of the circumstances around the creation of each archive, the corporate body or individual responsible for it and its structure is provided. Each archival unit is identified by its key elements: chronological date, name and qualification of the notary, original/copy, main editions.

Spectrophotometric study of holmium complexation in KOH solutions at 25 Deg C

International Nuclear Information System (INIS)

Stepanchikova, S.A.; Bitejkina, R.P.

2006-01-01

Complexation of Ho 3+ in solutions of HoCl 3 and KOH at 25 Deg C is studied by indicator spectrophotometric method. Within the range of pH 9.25-10.10 and μ≤4 x 10 -4 stability constants of Ho 3+ hydroxocomplexes are measured and are extrapolated on zero ion strength [ru

Increase of thermal conductivity of uranium dioxide nuclear fuel pellets with beryllium oxide addition; Condutividade termica de pastilhas de combustivel nuclear de UO{sub 2}-BeO nas temperaturas de 25 deg C e 100 deg C

Energy Technology Data Exchange (ETDEWEB)

Camarano, D.M.; Mansur, F.A.; Santos, A.M.M. dos; Ferraz, W.B., E-mail: dmc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTM/CNEN-MG), Belo Horizonte, MG (Brazil)

2016-07-01

The UO{sub 2} fuel is one of the most used nuclear fuel in thermal reactors and has many advantages such as high melting point, chemical compatibility with cladding, etc. However, its thermal conductivity is relatively low, which leads to a premature degradation of the fuel pellets due to a high radial temperature gradient during reactor operation. An alternative to avoid this problem is to increase the thermal conductivity of the fuel pellets, by adding beryllium oxide (BeO). Pellets of UO{sub 2} and UO{sub 2}-BeO were obtained from a homogenized mixture of powders of UO{sub 2} and BeO, containing 2% and 3% by weight of BeO and sintering at 1750 °C for 3 h under H{sub 2} atmosphere after uniaxial pressing at 400 MPa. The pellet densities were obtained by xylol penetration-immersion method and the thermal diffusivity, specific heat and thermal conductivity were determined according to ASTM E-1461 at room temperature (25 deg C) and 100 deg C. The thermal diffusivity measurements were carried out employing the laser flash method. The thermal conductivity obtained at 25 deg C showed an increase with the addition of 2% and 3% of BeO corresponding to 19% and 28%, respectively. As for the measurements carried out at 100 deg C, there was an increase in the thermal conductivity for the same BeO contents of 20% and 31%. These values as a percentage of increased conductivity were obtained in relation to the UO{sub 2} pellets. (author)

The Drosophila gene CheB42a is a novel modifier of Deg/ENaC channel function.

Directory of Open Access Journals (Sweden)

Yehuda Ben-Shahar

2010-02-01

Full Text Available Degenerin/epithelial Na(+ channels (DEG/ENaC represent a diverse family of voltage-insensitive cation channels whose functions include Na(+ transport across epithelia, mechanosensation, nociception, salt sensing, modification of neurotransmission, and detecting the neurotransmitter FMRFamide. We previously showed that the Drosophila melanogaster Deg/ENaC gene lounge lizard (llz is co-transcribed in an operon-like locus with another gene of unknown function, CheB42a. Because operons often encode proteins in the same biochemical or physiological pathway, we hypothesized that CHEB42A and LLZ might function together. Consistent with this hypothesis, we found both genes expressed in cells previously implicated in sensory functions during male courtship. Furthermore, when coexpressed, LLZ coprecipitated with CHEB42A, suggesting that the two proteins form a complex. Although LLZ expressed either alone or with CHEB42A did not generate ion channel currents, CHEB42A increased current amplitude of another DEG/ENaC protein whose ligand (protons is known, acid-sensing ion channel 1a (ASIC1a. We also found that CHEB42A was cleaved to generate a secreted protein, suggesting that CHEB42A may play an important role in the extracellular space. These data suggest that CHEB42A is a modulatory subunit for sensory-related Deg/ENaC signaling. These results are consistent with operon-like transcription of CheB42a and llz and explain the similar contributions of these genes to courtship behavior.

Release of fission products during and after oxidation of trace-irradiated uranium dioxide at 300-900 deg. C

Energy Technology Data Exchange (ETDEWEB)

Wood, P; Bannister, G H [Central Electricity Generating Board, Berkeley Nuclear Laboratories (United Kingdom)

1985-07-01

Should defected UO{sub 2} fuel pins come into contact with air then oxidation of the fuel may occur, the rate and consequences of which are dependent upon temperature and oxygen partial pressure. At CEGB-BNL an experimental programme is underway investigating the kinetics, and extent, of release of fission products during and after oxidation of trace-irradiated UO{sub 2} to U{sub 3}O{sub 8}, and reduction of U{sub 3}O{sub 8} to UO{sub 2}. This paper presents preliminary results and analysis of experiments performed at 300-900 deg. C. Dense sintered UO{sub 2} has been oxidised at 300-500 deg. C using a thermo balance with simultaneous counting of released {sup 85}Kr. The kinetics of the {sup 85}Kr release are shown to correlate with the kinetics of oxidation, and the extent of release has been determined as 3-8% of that in the UO{sub 2} converted to U{sub 3}O{sub 8}. The release of {sup 106}Ru and {sup 137}Cs during this oxidation has been estimated by {gamma}-counting of the fuel sample, before and after oxidation, and of glassware in the vicinity of the sample. This indicates slight release of ruthenium and caesium. Greater fission product release is caused by oxidation at higher temperatures or by heating of the oxidation product. U{sub 3}O{sub 8} produced at 400 deg. C has been heated at 800 and 900 deg. C in air for 20 hours. This results in near total release of {sup 85}Kr and {sup 106}Ru, but still only slight release of {sup 137}Cs. The kinetics of the {sup 85}Kr release have been analysed and found to follow the Booth diffusion equation at 900 deg. C, but not at 800 deg. C. The fuel burn-up level may also have an effect. Some results of fission product release during reduction of the oxidation product U{sub 3}O{sub 8} are presented, and the influence of chemical effects upon the release of individual fission products is discussed. The future programme is outlined. (author)

Inhibition between 350 and 500 deg. C of the corrosion of magnesium by damp air; Inhibition entre 350 et 500 deg. C de la corrosion du magnesium par l'air humide

Energy Technology Data Exchange (ETDEWEB)

Darras, Raymond; Caillat, Roger [Commissariat a l' energie atomique et aux energies alternatives - CEA (France)

1960-07-01

It has been demonstrated that the formation of a fluoride layer on the surface of magnesium by either dry or wet methods raises the temperature to which it resists corrosion in damp air from 350 to 490 deg. C. This protection effect could lead to a revision of the Pilling and Bedworth rule. Reprint of a paper published in 'Comptes Rendus des Seances de l'Academie des Sciences', tome 249, p. 1517-1519, sitting of 19 October 1959 [French] Il a ete montre que la formation d'une couche fluoree a la surface du magnesium, soit par voie seche, soit par voie humide, permet d'elever de 350 a 490 deg. C la temperature jusqu'a laquelle il resiste a la corrosion dans l'air humide. Cet effet protecteur pourrait conduire a revoir la regle de Pilling et Bedworth. Reproduction d'un article publie dans les 'Comptes Rendus des Seances de l'Academie des Sciences', tome 249, p. 1517-1519, seance du 19 octobre 1959.

A constitutional investigation of the Mo-Pd-Rh ternary system at 1100deg C

International Nuclear Information System (INIS)

Guerler, R.; Pratt, J.N.

1991-01-01

Phase relations in the system Mo-Pd-Rh were studied at 1100deg C using conventionally melted and ultrarapidly solidified samples. Optical microscopy, X-ray diffraction, scanning electron microscopy and electron probe microanalysis were used for phase characterisation. The complete isothermal section at 1100deg C was established. The Mo bcc phase was found to have a very limited solid solution range whereas the ternary fcc solid solution originating on the Pd-Rh binary is the dominant phase in the system at this temperature. The centre of the isothermal is dominated by the ternary extension of the Mo-Rh hcp intermediate phase. The three phase (bcc+fcc+hcp) equilibrium region is located very near to the Mo-Pd binary system. No additional ternary intermediate phases were observed. The results are consistent with an isothermal section reported at higher temperatures. (orig.)

Molecular dynamics simulations of the interaction between 60 deg. dislocation and self-interstitial cluster in silicon

International Nuclear Information System (INIS)

Jing Yuhang; Meng Qingyuan; Zhao Wei

2009-01-01

Molecular dynamics simulations are performed to investigate the interaction between 60 deg. shuffle dislocation and tetrainterstitial (I 4 ) cluster in silicon, using Stillinger-Weber (SW) potential to calculate the interatomic forces. Based on Parrinello-Rahman method, shear stress is exerted on the model to move the dislocation. Simulation results show that the I 4 cluster can bend the dislocation line and delay the dislocation movement. During the course of intersection the dislocation line sections relatively far away from the I 4 cluster accelerate first, and then decelerate. The critical shear stress unpinning the 60 deg. dislocation from the I 4 cluster decreases as the temperature increases in the models.

Deformation behaviour of type 316 steel at 400 deg. C

International Nuclear Information System (INIS)

Wood, D.S.; Williamson, K.

A variety of type 316 steel deformation tests at 400 deg. C involving a study of strain rate, stress increment, stress cycling and strain cycling effects are reported. It is concluded that very small ratchet strains may occur, but these are unlikely to be of engineering significance. It is also shown that in the absence of reversed plasticity the upper stress bound is represented by the monotonic stress-strain curve. Under reversed plasticity, significant cyclic hardening can occur and in this case the upper bound may be represented by the cyclic stress-strain curve

High-resolution 8-13 micron imaging of the planetary nebulae BD + 30 deg 3639 and NGC 6572

International Nuclear Information System (INIS)

Hora, J.L.; Hoffmann, W.F.; Deutsch, L.K.; Fazio, G.G.

1990-01-01

High-resolution midinfrared images of the planetary nebulae BD + 30 deg 3639 and NGC 6572 are presented at 8.3, 8.7, 9.8, 11.2, and 12.4 microns. Analysis of the maps of BD + 30 deg 3639 supports a model in which the infrared emission originates from two spatially distinct components, one which is responsible for the continuum radiation at 8-12 microns and the other which produces the emission-line features. The NGC 6572 images provides evidence for a previously undetected 11.2 micron UIR emission feature. Comparison with radio continuum maps indicates that the distribution of dust is similar to the distribution of ionized gas in each nebula. Various models of source morphology are also investigated. The planetary nebulae DB + 30 deg 3639 and NGC 6572 can be modeled by an optically thin cylinder or a prolate ellipsoid with enhanced equatorial emission. These models reproduce well the general features of the nebula, such as the bipolar lobes of emission and the ring structure. 67 refs

Crustal structure of the Churchill-Superior boundary zone between 80 and 98 deg W longitude from Magsat anomaly maps and stacked passes

Science.gov (United States)

Hall, D. H.; Millar, T. W.; Noble, I. A.

1985-01-01

A modeling technique using spherical shell elements and equivalent dipole sources has been applied to Magsat signatures at the Churchill-Superior boundary in Manitoba, Ontario, and Ungava. A large satellite magnetic anomaly (12 nT amplitude) on POGO and Magsat maps near the Churchill-Superior boundary was found to be related to the Richmond Gulf aulacogen. The averaged crustal magnetization in the source region is 5.2 A/m. Stacking of the magnetic traces from Magsat passes reveals a magnetic signature (10 nT amplitude) at the Churchill-Superior boundary in an area studied between 80 deg W and 98 deg W. Modeling suggests a steplike thickening of the crust on the Churchill side of the boundary in a layer with a magnetization of 5 A/m. Signatures on aeromagnetic maps are also found in the source areas for both of these satellite anomalies.

An evaluation of the +/-45 deg tensile test for the determination of the in-plane shear strength of composite materials

Science.gov (United States)

Kellas, S.; Morton, J.; Jackson, K. E.

1991-01-01

The applicability of the +/-45 deg tensile test for the determination of the in-plane shear strength of advanced composite laminates is studied. The assumptions used for the development of the shear strength formulas were examined, and factors such as the specimen geometry and stacking sequence were assessed experimentally. It was found that the strength of symmetric and balanced +/-45 deg laminates depends primarily upon the specimen thickness rather than the specimen width. These findings have important implications for the +/-45 deg tensile test which is recommended by several organizations for the determination of the in-plane shear stress/strain response and the shear strength of continuous fiber reinforced composites. Modifications to the recommended practices for specimen selection and shear strength determination are suggested.

In-situ pH measurements and sample analyses in glass-iron-clay systems at 90 deg. C and 150 deg. C

International Nuclear Information System (INIS)

Rozsypal, Christophe; Mosser-Ruck, Regine; Truche, Laurent; Pignatelli, Isabella; Randi, Aurelien; Bartier, Daniele; Cathelineau, Michel; Michau, Nicolas

2012-01-01

Document available in extended abstract form only. The long term repository of long life and high activity radioactive waste consists in the burial of steel overpacks of vitrified waste in a clay-stone. As the natural interstitial fluid of the clay-stone is a potential corrosion enhancer for the containers, the viability of the repository requires previous data acquisition on the interactions between clays, water, metallic iron, and glass. A set of experiments have been performed in autoclaves at 90 deg. C (thermal peak of the site) in order to follow the pH evolution and to characterize fluids with time and solids at the end of the experiments. Another set of experiments at 150 deg. C have also been carried out in order to increase the rates of the involved chemical reactions and mineralogical transformations. The objectives of those two sets of experiments were to measure the in-situ pH, to study how it was influenced by various parameters, such as the presence of glass and/or iron, to estimate the increase of the CO 2 and H 2 pressures, and to analyze gas and liquids taken in the course or at the end of experiments and solids recovered at the end of the experiments. The initial aqueous solution simulating the natural interstitial fluid was made of 22 mM of sodium, 4 mM of calcium, 29.75 mM of chloride, and 0.25 mM of bromide as a tracer. The initial solution/clay mass ratio was 10 for all the experiments, the metallic iron/clay or glass/clay mass ratios were 0.1 or 0. The list of the experiments and their characteristics is given in Table (1). The first results concern the evolution of the in-situ pH during the A90pH experiment and are reported on Figure (1). The measurements started after a 48 hours stabilization time of the pH probe. The pH seemed to tend reaching a plateau after several weeks. (authors)

Corrosion behavior of silicon nitride in sodium hydroxide solutions at 175 deg C

International Nuclear Information System (INIS)

Strecker, Kurt; Robin, Alain; Vernilli, Fernando; Ribeirao, Sebastiao

1996-01-01

This paper presents results of the corrosion of Si 3 N 4 in aqueous solutions of NaOH (37,5%) at 15 deg C.The corrosive attack was evaluated from the weight loss of the samples.A constant rate was observed, signifying that the corrosion rate depends only on the velocity of the dissolution by the NaOH solution. The corrosion rates of Si 3 N 4 doped with Y 2 O 3 / Si O 2 and a rare earth concentrate/Si O 2 yielded 1,19 x 10 -3 g cm -2 h -1 and 0,78 x 10 -3 g cm -2 h -1 , respectively. Analysis of the corroded samples by electronic microscopy revealed that the glassy intergranular phase is dissolved by the alkaline solution, leaving a skeleton of inter linked β - Si 3 N 4 grains. The mechanical resistance of the corroded samples was determined and demonstrated mechanical degradation of the material. (author)

Investigation of the thermal stability of 210 deg. C TL peak of quartz and dating the components of terrazzo from the monastery church of Tegernsee

International Nuclear Information System (INIS)

Goeksu, H.Y.; Schwenk, P.; Semiochkina, N.

2001-01-01

The lifetime of the thermoluminescence (TL) peak of quartz observed at 210 deg. C using 5 deg. C/s heating rate is assessed using well-dated thermally isolated bricks from a monastery and exposed bricks from warmer climatic zones by comparing the absorbed dose obtained using the 210 deg. C TL peak with those obtained from 310 deg. C TL peak. The lifetimes of the 210 deg. C TL peak calculated for samples collected from thermally isolated excavations and exposed buildings are found to be clustered around 8000-10000 and 600-800 years, respectively. The results proved that 210 deg. C TL peak could be used for dating of samples younger than 1000 years without thermal correction if the samples are thermally isolated from their environment. TL ages are obtained using quartz, polyminerals from brick pieces as well as flint splinters, and other quartz inclusions extracted from the mortar of the terrazzo floor of the monastery church. The measured TL ages and the consistency of the results are discussed. The fine grains in the mortar, which contained calcite/aragonite, could not be dated using thermoluminescence due to presence of a very strong non-radiation induced TL glow

Educazione linguistica e bisogni degli alunni (stranieri.

Directory of Open Access Journals (Sweden)

Marina Chini

2009-12-01

Full Text Available Normal 0 14 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabella normale"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} L’articolo focalizza l’attenzione sui bisogni linguistici e comunicativi specifici degli allievi nativi e immigrati, al fine di evidenziare alcuni suggerimenti che è possibile trarne sul piano dell’educazione linguistica, intesa nel senso dell’insegnamento rivolto allo sviluppo e al potenziamento delle abilità linguistico-comunicative, ma anche metalinguistiche, svolto trasversalmente dai docenti di discipline linguistiche e non.  Tenendo conto di principi e suggerimenti emersi dalla riflessione glottodidattica e linguistica degli ultimi decenni si forniscono criteri in base ai quali i docenti possono rilevare i bisogni linguistici dei loro allievi, bisogni che si correlano a valenze di carattere comunicativo, pragmatico, espressivo e culturale-matetico, ma che sono anche di natura sociale, relazionale e affettiva, identitaria e psicologica oltre che cognitiva.  Normal 0 14 MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabella normale"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} The article focuses on the specific linguistic and communicative needs of native and immigrant pupils, in order to draw attention to inspiration  that can be gained for general linguistic education, seen as teaching that aims to develop and strengthen linguistic-communicative abilities but also meta-linguistic ones – teaching that is carried

High levels of DegU-P activate an Esat-6-like secretion system in Bacillus subtilis.

Directory of Open Access Journals (Sweden)

Catarina Baptista

Full Text Available The recently discovered Type VII/Esat-6 secretion systems seem to be widespread among bacteria of the phyla Actinobacteria and Firmicutes. In some species they play an important role in pathogenic interactions with eukaryotic hosts. Several studies have predicted that the locus yukEDCByueBC of the non-pathogenic, Gram-positive bacterium Bacillus subtilis would encode an Esat-6-like secretion system (Ess. We provide here for the first time evidences for the functioning of this secretion pathway in an undomesticated B. subtilis strain. We show that YukE, a small protein with the typical features of the secretion substrates from the WXG100 superfamily is actively secreted to culture media. YukE secretion depends on intact yukDCByueBC genes, whose products share sequence or structural homology with known components of the S. aureus Ess. Biochemical characterization of YukE indicates that it exists as a dimer both in vitro and in vivo. We also show that the B. subtilis Ess essentially operates in late stationary growth phase in absolute dependence of phosphorylated DegU, the response regulator of the two-component system DegS-DegU. We present possible reasons that eventually have precluded the study of this secretion system in the B. subtilis laboratory strain 168.

Experimental determination of cesium saturated vapor pressure in the 483/642 deg K temperature

Energy Technology Data Exchange (ETDEWEB)

Gushchin, G I; Subbotin, V A; Khachaturov, Eh Kh [Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Obninsk. Fiziko-Ehnergeticheskij Inst.

1975-07-01

Test results of saturated cesium vapour pressure in the temperature range of 483.13-642 deg K and pressure range of 15.77-1.389 N/m/sup 2/ by direct static method are presented. The testing system comprises a differential bellows-type pressure sensor, a thermostatic unit and a gas system with V-shaped oil manometer used for argon-assisted sensor calibration. The static sensor characteristic approaches linearity in the pressure range of 10-600 N/m/sup 2/. The greatest non-linearity is observed at low pressures (10-40 N/m/sup 2/) and does not exceed 3-4%. Sensor sensitivity is 0.39 mV/N/m/sup 2/ in this pressure range. The characteristic hysteresis is 0.5% and below. With pressures greater than 600 N/m/sup 2/, the sensor sensitivity gradually decreases by 12% while the characteristic hysteresis increases to 2-3%. A brief description of the experimental procedure is offered. The present results are compared with other authors' data.

Corrosion of stainless steels in lead-bismuth eutectic up to 600 deg. C

International Nuclear Information System (INIS)

Soler, L.; Martin, F.J.; Hernandez, F.; Gomez-Briceno, D.

2004-01-01

An experimental program has been carried out to understand the differences in the corrosion behaviour between different stainless steels: the austenitic steels 304L and 316L, the martensitic steels F82Hmod, T91 and EM10, and the low alloy steel P22. The influence of oxygen level in Pb-Bi, temperature and exposure time is studied. At 600 deg. C, the martensitic steels and the P22 steel exhibit thick oxide scales that grow with time, following a linear law for the wet environment and a parabolic law for the dry one. The austenitic stainless steels show a better corrosion behaviour, especially AISI 304L. Under reducing conditions, the steels exhibit dissolution, more severe for the austenitic stainless steels. At 450 deg. C, all the materials show an acceptable behaviour provided a sufficient oxygen level in the Pb-Bi. At reducing conditions, the martensitic steels and the P22 steel have a good corrosion resistance, while the austenitic steels exhibit already dissolution at the longer exposures

Effects of heat treatments and neutron irradiation on the physical and mechanical properties of copper alloys at 100 deg. C

International Nuclear Information System (INIS)

Singh, B.N.; Eldrup, M.; Toft, P.; Edwards, D.J.

1998-05-01

The final irradiation experiment in a series of screening experiments aimed at investigating the effects of bonding and bakeout thermal cycles on irradiated copper alloys is described herein. Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime-ageing and bonding thermal treatment. Additional specimens were reaged and given a reactor bakeout treatment at 350 deg. C for 100 h. GlidCop TM CuAl-15 (previously referred to as CuAl-25) was given a heat treatment corresponding to a bonding thermal cycle only. Specimens were neutron irradiated at 100 deg. C to a dose level of ∼0.3 dpa. Post-irradiation tensile tests at (100 deg. C), electrical resistivity measurements (at 23 deg. C), and microstructural examinations were performed. The post-irradiation tests at 100 deg. C revealed that the greatest loss of ductility occurred in the CuCrZr alloys irradiated at 100 deg. C, irrespective of the pre-irradiation heat treatment, with the uniform elongation dropping to levels of less than 1.5%. The yield and ultimate strengths for all of the individual heat treated samples increased substantially after irradiation. The same trend was observed for the CuNiBe alloys, which exhibited much higher uniform elongation and strength after irradiation than that observed in the case of CuCrZr alloys. In both alloys irradiation-induced precipitation lead to a large increase in the strength of the solution annealed specimens with a noticeable decrease in uniform elongation. The CuAl-25 alloy also experienced an increase in the overall strength of the alloy after irradiation, accompanied by approximately a 50% decrease in the uniform and total elongation. The additional bakeout treatments given to the CuCrZr and CuNiBe before irradiation served to increase the strength, but in terms of the ductility no improvement or degradation resulted from the additional thermal exposure

AN XMM-NEWTON SURVEY OF THE SOFT X-RAY BACKGROUND. I. THE O VII AND O VIII LINES BETWEEN l = 120 DEG. AND l = 240 DEG

International Nuclear Information System (INIS)

Henley, David B.; Shelton, Robin L.

2010-01-01

We present measurements of the soft X-ray background (SXRB) O VII and O VIII intensity between l = 120 deg. and l = 240 deg., the first results of a survey of the SXRB using archival XMM-Newton observations. We do not restrict ourselves to blank-sky observations, but instead use as many observations as possible, removing bright or extended sources by hand if necessary. In an attempt to minimize contamination from near-Earth solar wind charge exchange (SWCX) emission, we remove times of high solar wind proton flux from the data. Without this filtering we are able to extract measurements from 586 XMM-Newton observations. With this filtering, ∼1/2 of the observations are rendered unusable, and we are able to extract measurements from 303 observations. The oxygen intensities are typically ∼0.5-10 photons cm -2 s -1 sr -1 (line units, L.U.) for O VII and ∼0-5 L.U. for O VIII. The proton flux filtering does not systematically reduce the oxygen intensities measured from a given observation. However, the filtering does preferentially remove the observations with higher oxygen intensities. Our data set includes 69 directions with multiple observations, whose oxygen intensity variations can be used to constrain SWCX models. One observation exhibits an O VII enhancement of ∼25 L.U. over two other observations of the same direction, although most SWCX enhancements are ∼ 6 K, in good agreement with previous studies.

Biological effects of diethylene glycol (DEG) and produced waters (PWs) released from offshore activities: A multi-biomarker approach with the sea bass Dicentrarchus labrax

Energy Technology Data Exchange (ETDEWEB)

Stefania, Gorbi; Maura, Benedetti [Dipartimento di Biochimica, Biologia e Genetica, Universita Politecnica delle Marche, Via Ranieri, Monte d' Ago, 60121 Ancona (Italy); Claudia, Virno Lamberti [Istituto Superiore per la Ricerca e la Protezione Ambientale (ISPRA), Via di Casalotti 300 Roma (Italy); Barbara, Pisanelli [Dipartimento di Biochimica, Biologia e Genetica, Universita Politecnica delle Marche, Via Ranieri, Monte d' Ago, 60121 Ancona (Italy); Ginevra, Moltedo [Istituto Superiore per la Ricerca e la Protezione Ambientale (ISPRA), Via di Casalotti 300 Roma (Italy); Francesco, Regoli, E-mail: f.regoli@univpm.i [Dipartimento di Biochimica, Biologia e Genetica, Universita Politecnica delle Marche, Via Ranieri, Monte d' Ago, 60121 Ancona (Italy)

2009-11-15

Diethylene glycol (DEG) is largely used during oil and gas exploitation by offshore platforms. The aim of this work was to investigate if this compound induces direct molecular/cellular effects in marine organisms, or indirectly modulate those of produced waters (PWs). Sea bass (Dicentrarchus labrax) were exposed to DEG dosed alone or in combination with PWs from an Adriatic platform. A wide array of analysed biomarkers included cytochrome P450-dependent enzymatic activity, bile metabolites, glutathione S-transferases, acetylcholinesterase, peroxisomal proliferation, antioxidant defences (catalase, glutathione reductase, glutathione peroxidases, glutathione), total oxyradical scavenging capacity, malondialdehyde and DNA integrity (single strand breaks and frequency of micronuclei). Results did not reveal marked effects of DEG, while PWs influenced the biotransformation system, the oxidative status and the onset of genotoxic damages. Co-exposures caused only limited differences of biomarker responses at some experimental conditions, overall suggesting a limited biological impact of DEG at levels normally deriving from offshore activities. - A biological risk for marine organisms can be excluded for DEG concentrations as those normally associated to produced waters discharged in the Adriatic Sea.

Biological effects of diethylene glycol (DEG) and produced waters (PWs) released from offshore activities: A multi-biomarker approach with the sea bass Dicentrarchus labrax

International Nuclear Information System (INIS)

Stefania, Gorbi; Maura, Benedetti; Claudia, Virno Lamberti; Barbara, Pisanelli; Ginevra, Moltedo; Francesco, Regoli

2009-01-01

Diethylene glycol (DEG) is largely used during oil and gas exploitation by offshore platforms. The aim of this work was to investigate if this compound induces direct molecular/cellular effects in marine organisms, or indirectly modulate those of produced waters (PWs). Sea bass (Dicentrarchus labrax) were exposed to DEG dosed alone or in combination with PWs from an Adriatic platform. A wide array of analysed biomarkers included cytochrome P450-dependent enzymatic activity, bile metabolites, glutathione S-transferases, acetylcholinesterase, peroxisomal proliferation, antioxidant defences (catalase, glutathione reductase, glutathione peroxidases, glutathione), total oxyradical scavenging capacity, malondialdehyde and DNA integrity (single strand breaks and frequency of micronuclei). Results did not reveal marked effects of DEG, while PWs influenced the biotransformation system, the oxidative status and the onset of genotoxic damages. Co-exposures caused only limited differences of biomarker responses at some experimental conditions, overall suggesting a limited biological impact of DEG at levels normally deriving from offshore activities. - A biological risk for marine organisms can be excluded for DEG concentrations as those normally associated to produced waters discharged in the Adriatic Sea.

“Intonazioni degli Ebrei” from Benedetto Marcello’s Estro poetico-armonico in Prague in 1729

Czech Academy of Sciences Publication Activity Database

Jonášová, Milada

2015-01-01

Roč. 52, č. 1 (2015), s. 5-54 ISSN 0018-7003 R&D Projects: GA ČR(CZ) GAP409/12/2563 Keywords : Benedetto Marcello * Intonazioni degli Ebrei * Prague Subject RIV: AL - Art, Architecture, Cultural Heritage

Thermocouple calibration facility for 2900 deg C high temperature and its applications

International Nuclear Information System (INIS)

Chen Daolong

1991-01-01

The construction and the performance characteristic of a 2900 deg C high temperature thermocouple calibration facility are described. The calibration error analysis is made. The test results of the calibration characteristics of high temperature thermocouples Mo/Nb, W-3Re/W-25Re, and W-1Mo/W-25Mo are given. The test result of temperature dependent resistivity of BeO made by this facility is given

On the formation of the L-centre in silicon during heat treatment in the temperature range 205-285 deg. C

International Nuclear Information System (INIS)

Mikelsen, M; Monakhov, E V; Avset, B S; Svensson, B G

2006-01-01

Annealing kinetics of electron-irradiation induced defects in n-type diffusion oxygenated float-zone silicon has been studied in the temperature-range 205-285 deg. C. Previous deep level transient spectroscopy (DLTS) reports have established that an observed shift in the positions of two peaks related to the divacancy (V 2 ), is due to the annealing of the divacancy and the formation of the divacancy-oxygen complex (V 2 O). In parallel to this transformation from V 2 to V 2 O, a new defect of unknown identity, the so-called L-centre, forms with a level located at 0.36 eV below the conduction band edge. The L-level has a first order formation-kinetics in the temperature region studied; at 245-285 deg. C the formation rate is very similar to the annealing rate of V 2 , while at lower temperatures the formation rate becomes lower with a relative difference by a factor two at 205 deg. C. The Arrhenius plot for the L-level formation rate is not a straight line, indicating that the formation is controlled by at least two different processes. Kinetic modelling shows that the experimental data can be reproduced by a sequence of defect dissociation and migration, where the former limits at low temperatures (activation energy ∼1.75 eV) and the latter at high temperatures (E a ∼1.0 eV). Based on these results and other findings, the identity of the L-centre is discussed

Rehydration and microstructure of cement paste after heating at temperatures up to 300 deg. C

International Nuclear Information System (INIS)

Farage, M.C.R.; Sercombe, J.; Galle, C.

2003-01-01

This paper is concerned with the evolution of the microstructure of cementitious materials subjected to high temperatures and subsequent resaturation in the particular context of long-term storage of radioactive wastes, where diffusive and convective properties are of primary importance. Experimental results obtained by mercury intrusion porosimetry (MIP) are presented concerning the evolution of the pore network of ordinary portland cement (OPC) paste heated at temperatures varying between 80 and 300 deg. C. The consequences of heating on the macroscopic properties of cement paste are evaluated by measures of the residual gas permeabilities, elastic moduli and Poisson's ratio, obtained by nondestructive methods. Resaturation by direct water absorption and water vapour sorption are used to estimate the reversibility of dehydration. The results provide some evidence of the self-healing capacity of resaturated cement paste after heating at temperatures up to 300 deg. C

Oxidation kinetics of simulated metallic spent fuel in air at 200∼300 .deg. C

International Nuclear Information System (INIS)

Joo, J. S.; Yoo, K. S.; Jo, I. J.; Kook, D. H.; Lee, E. P.; Lee, J. C.; Bang, K. S.; Kim, H. D.

2003-01-01

In order to evaluate the long term storage safety study of the metallic spent fuel, U-5Zr, U-5Ti, U-5Ni, U-5Nb, and U-5Hf simulated metallic uranium alloys, known as corrosion resistant alloys, were fabricated and oxidized in oxygen gas at 200 .deg. C ∼ 300 .deg. C. All simulated metallic uranium alloys were more corrosion resistant than pure uranium metal, and corrosion resistance increases Nb, Ni, Ti, Zr, Hf in that order. The oxidation rates of uranium alloys determined and activation energy was calculated for each alloy. The matrix microstructure of the test specimens were analyzed using OM, SEM, and EPMA. It was concluded that Nb was the best acceptable alloying elements for reducing corrosion of uranium metal, and Ni, Ti were also considered to suitable as candidate

Spin-orbit coupling in InGaSb/InAlSb and InGaAs/InP 2DEGs

International Nuclear Information System (INIS)

Guzenko, Vitaliy A.; Schaepers, Thomas; Estevez, Sergio; Hardtdegen, Hilde; Akabori, Masashi; Sato, Taku; Suzuki, Toshi-kazu; Yamada, Syoji

2008-01-01

Spin-orbit interaction in high-mobility two-dimensional electron gases (2DEGs) formed in high indium content InGaAs-based and InGaSb-based quantum wells was studied. Magnetotransort measurements were performed at low temperatures in a wide range of magnetic field. Characteristic beating pattern in the Shubnikov-de Haas oscillations as well as the enhancement of magnetoconductance at B=0 T due to weak antilocalization (WAL) effect were observed. A comparison of the values of the Rashba spin-orbit coupling parameters estimated from analysis of the beatings with the ones obtained from the fit of the WAL curves showed a good agreement. A control over the strength of the Rashba coupling parameter in the InGaAs 2DEG was achieved by applying a gate voltage. We found that in particular range of the negative gate voltages no beatings can be observed anymore, whereas the weak antilocalization becomes more pronounced. Under such conditions analysis of the WAL is a reliable method to determine the strength of the spin-orbit interaction in 2DEGs

Changes in the microflora of Vienna sausages after irradiation with gamma-rays and storage at 10 deg C

International Nuclear Information System (INIS)

Ito, Hitoshi; Sato, Tomotaro

1973-01-01

The species of microorganisms which can grow on commercial viennas on the storage at 10 deg C were Lactobacillus, Streptococcus and yeasts. When the viennas specially made which did not contain preservatives in it were used for this investigation, growth of microorganisms such as Lactobacillus, Streptococcus, Micrococcus, Bacillus and yeasts were predominant on the storage at 10 deg C, and Pseudomonas and molds some time propagated. When smoked-viennas specially made for the National Project were used for preservation, growth of microorganisms consisted mainly of the species of Lactobacillus, Micrococcus, Acinetobacter, Flavobacterium, Streptococcus, Serratia, Corynebacterium and yeasts. Irradiation of viennas at 300 and 500 krad reduced the aforementioned flora to the Lactobacillus, Streptococcus, Acinetobacter and yeasts. The number of microorganisms on the viennas packed with nitrogen gas was not increased for 3 to 7 days by means of 300 krad irradiation, and extended the storage-life 2 to 3 times. When irradiated with a dose of 500 krad, the number of microorganisms was not increased for 9 to 14 days on the storage at 10 deg C. (author)

A study of non-ideal focus properties of 30deg parallel plate energy analyzers

International Nuclear Information System (INIS)

Fujisawa, A.; Iguchi, H.; Hamada, Y.

1993-12-01

A succinct model is proposed to describe non-ideal characteristics owing to electric field penetration into the drift region in actual parallel plate energy analyzers. A good agreement has been obtained between the theoretically expected and experimentally observed focus properties of the 30deg parallel plate analyzer. (author)

Phase equilibria in Dy-Cu-Al system at 500 deg C

International Nuclear Information System (INIS)

Kuz'ma, Yu.B.; Milyan, V.V.

1989-01-01

Using the methods of X-ray diffraction analysis a diagram of phase equilibria in Dy-Cu-Al system at 500 deg C is plotted. Boundaries of solid solutions on the basis of DyCu 2 , DyCu and DyAl 2 compounds are determined and homogeneity regions of ternary compounds Dy 2 (Cu, Al) 7 and Dy(CuAl) 5 are ascertained. Compounds DyCuAl 3 , Dy 4 Cu 4 Al 11 and Dy 5 Cu 6 Al 9 have been detected for the first time

Fluctuations in the cosmic microwave background on a 2.3 deg angular scale

International Nuclear Information System (INIS)

Calzolari, P.; Cortiglioni, S.; Mandolesi, N.

1982-01-01

The study of fluctuations in the temperature of the cosmic microwave background may provide important information on the origin of the large scale structures in the Universe. An experiment is in operation at Medicina (Bologna) for studying such temperature fluctuations on a 2 deg 3 angular scale at lambda=2.8 cm. Preliminary results seem to indicate ΔT/T -4

Effects of 42 deg. C hyperthermia on intracellular pH in ovarian carcinoma cells during acute or chronic exposure to low extracellular pH

International Nuclear Information System (INIS)

Wahl, Miriam L.; Bobyock, Suzanne B.; Leeper, Dennis B.; Owen, Charles S.

1997-01-01

Purpose: To determine whether intracellular pH (pH i ) is affected during hyperthermia in substrate-attached cells and whether acute extracellular acidification potentiates the cytotoxicity of hyperthermia via an effect on pH i . Methods and Materials: The pH i was determined in cells attached to extracellular matrix proteins loaded with the fluorescent indicator dye BCECF at 37 deg. C and during 42 deg. C hyperthermia at an extracellular pH (pH e ) of 6.7 or 7.3 in cells. Effects on pH i during hyperthermia are compared to effects on clonogenic survival after hyperthermia at pH e 7.3 and 6.7 of cells grown at pH e 7.3, or of cells grown and monitored at pH e 6.7. Results: The results show that pH i values are affected by substrate attachments. Cells attached to extracellular matrix proteins had better signal stability, low dye leakage and evidence of homeostatic regulation of pH i during heating. The net decrease in pH i in cells grown and assayed at pH e = 7.3 during 42 deg. C hyperthermia was 0.28 units and the decrease in low pH adapted cells heated at pH e = 6.7 was 0.14 units. Acute acidification from pH e = 7.3 to pH e = 6.7 at 37 deg. C caused an initial reduction of 0.5-0.8 unit in pH i , but a partial recovery followed during the next 60-90 min. Concurrent 42 deg. C hyperthermia caused the same initial reduction in pH i in acutely acidified cells, but inhibited the partial recovery that occurred during the next 60-90 min at 37 deg. C. After 4 h at 37 deg. C, the net change in pH i in acutely acidified cells was 0.30 pH unit, but at 42 deg. C is 0.63 pH units. The net change in pH i correlated inversely with clonogenic survival. Conclusions: Hyperthermia causes a pH i reduction in cells which was smaller in magnitude by 50% in low pH adapted cells. Hyperthermia inhibited the partial recovery from acute acidification that was observed at 37 deg. C in substrate attached cells, in parallel with a lower subsequent clonogenic survival

Superconducting transition and low-field magnetoresistance of a niobium single crystal at 4.2 deg. K; Transition supraconductrice et magnetoresistance en champ faible d'un echantillon monocristallin de niobium a 4.2 deg. K

Energy Technology Data Exchange (ETDEWEB)

Perriot, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Service de physique du solide et de resonnance magnetique

1967-01-01

We report the study of the electrical resistance of a niobium single crystal, at 4.2 deg. K, from the beginning of the superconductive transition to 80 kilo oersteds. Critical fieldsH{sub c2} and H{sub c3} have been determined. Influences on superconductive transition of current density, field-current angle, crystal orientation and magnetoresistance have been studied. Variation laws of low-field transverse and longitudinal magneto-resistances have been determined. (author) [French] La variation de la resistance electrique d'un monocristal cylindrique de niobium a ete etudiee, a 4,2 deg. K, depuis le debut de la transition supraconductrice jusqu'a 80 kilooersteds. Les champs critiques H{sub c2} et H{sub c3} ont ete determines. On a etudie l'influence de la densite de courant, de l'angle champ-courant, de l'anisotropie cristalline et de la magnetoresistance sur la transition supraconductrice. Les lois de variation des magnetoresistances transversale et longitudinale ont ete determinees dans le domaine des champs faibles. (auteur)

OMI/Aura Surface Reflectance Climatology Level 3 Global 0.5deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI Earth Surface Reflectance Climatology product, OMLER (Global 0.5deg Lat/Lon grid) which is based on Version 003 Level-1B top of atmosphere upwelling radiance...

L’esperienza MoULe dell’Università degli Studi di Milano-Bicocca

Directory of Open Access Journals (Sweden)

Michelle Pieri

2013-03-01

Full Text Available Questo contributo si focalizza sull’esperienza di mobile learning, con l’ambiente per l’apprendimento cooperativo MoULe, realizzata dall’Università degli studi di Milano- Bicocca in collaborazione con il Consiglio Nazionale delle Ricerche di Palermo. Un questionario1 sulle tecnologie e l’uso delle tecnologie è stato somministrato ai partecipanti prima dell’inizio dell’esperienza e alla fine dell’esperienza è stato realizzato un focus group con i partecipanti per valutare l’esperienza.

The system HoCl3-YCl3-H2O (25 deg C)

International Nuclear Information System (INIS)

Sorokina, A.A.; Yudina, N.G.

1981-01-01

By solubility method the system HoCl 3 -YCl 3 -H 2 O at 25 deg C has been studied. It is shown that in this system the continuous serie of solid solutions is formed. The liquid solutions of this system have been investigated by the isopiestic method. The values of activity coefficients, activity, free energy formation and excess free energy of solid solutions are calculated [ru

Complete dipole response in 208Pb from high-resolution polarized proton scattering at 0 deg

International Nuclear Information System (INIS)

Neumann-Cosel, P. von; Kalmykov, Y.; Poltoratska, I.; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Adachi, T.; Fujita, Y.; Matsubara, H.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Yosoi, M.; Bertulani, C. A.; Carter, J.; Fujita, H.; Dozono, M.; Fujita, K.; Hashimoto, H.; Hatanaka, K.

2009-01-01

The structure of electric and magnetic dipole modes in 208 Pb is investigated in a high-resolution measurement of the (p-vector,p-vector') reaction under 0 deg. First results on the E1 strength in the region of the pygmy dipole resonance are reported.

'Candidatus Phytoplasma sudamericanum' a novel taxon from diseased passion fruit (Passiflora edulis f. flavicarpa Deg.)

Science.gov (United States)

Symptoms of abnormal proliferation of shoots resulting in formation of witches’ broom growths were observed in diseased plants of passion fruit (Passiflora edulis f. flavicarpa Deg.) in Brazil. RFLP analysis of 16S rRNA gene sequences amplified in polymerase chain reactions containing template DNAs...

Relation between chemical properties in molten acetamide and water at 98 deg. C

International Nuclear Information System (INIS)

Petit, Nicole

1972-01-01

An attempt was made to establish the relation between the chemical properties of various cations in water and in molten acetamide at 98 deg. C. A solvent always possesses properties which have some effect on the reactivity of the solute. Various types of interactions (polar, electrostatic, Van der Waals forces, and hydrogen bonds) bind the solvent molecules to the dissolved molecules and ions. Interactions between the solute species and the solvent species are designated: solvation phenomena. In addition to solvation phenomena, another but less direct type of interaction occurs: the solvated ions find themselves in a sensibly continuous medium having a dielectric constant ε which can vary considerably. As the value of the dielectric constant decreases, the electrostatic interactions between the ions increase. The variation is such that these ions can only be considered free for values of ε > 40. This is the case for acetamide and water at 98 deg. C. The solvation of a chemical species belonging to an oxido-reducing system can only be effected by comparing the behavior of such a system with a reference system relatively insensitive to changes in the solvent. The reference system used was a ferrocene-ion/ferricinium couple. The solvation of a chemical species is characterized by a variable designated: the solvation activity coefficient. The chemical and electrochemical properties of various elements (alkali elements, alkaline earths, Cu, Zn, Cd, Hg, Pb, U, Al, Ce, and Eu) in neutral or acid media in acetamide were studied using various electrochemical techniques (principally polarography). These studies led to the establishment of a table of oxido-reducing potentials for molten acetamide. Comparisons with water at 98 deg. C indicate that the metallic cations are more solvated in acetamide than in water. The evaluation of solvation activity coefficients from polarographic measurements (E 1/2 , D M ) led to an approximate estimation of the differences in behavior

Per un'etica degli scambi economici. La funzione civile del mercato in Eiximenis e nella pedagogia politica francescana (1273-1493

Directory of Open Access Journals (Sweden)

Paolo Evangelisti

2014-03-01

dell’esercizio del potere, degli scambi nel mercato. Quest’ultimo identificato qual estruttura comunitaria, ovvero una vera e propria agorà civica all’interno della quale la dinamica delle negoziazioni non riguarda solo le merci ma implica anche una riflessione sui pre-requisiti che legittimano l’esistenza del mercato. I francescani, e segnatamente i testi eiximeniani, rivelano una spiccata capacità di interrogarsi sulle ragioni fondative del mercato e del denaro, sulle funzioni civili degli scambi economici e del credito.

Increasing seismic activity at 9deg50'N on the East Pacific Rise RIDGE 2000 Integrated Studies Site from October 2003 through April 2004

Science.gov (United States)

Weekly, R. T.; Tolstoy, M.; Waldhauser, F.; Bohnenstiehl, D. R.; Kim, W.

2005-12-01

Monitoring of micro-seismicity within the bull's-eye region of the R2K ISS at 9deg49'N - 9deg51'N on the East Pacific Rise has been ongoing since October 2003. Results from the first deployment (October 2003 - April 2004) will be presented with hypocenters determined using relative-relocation techniques. Analysis shows that there is a gradual and ongoing increase in the rate of activity over the 7 months of the deployment. Mean event rates increase from 31 events/day for the first quarter of the deployment period, to 55, 105, and 131 events per day for the 2nd, 3rd and 4th quarters, respectively. This gradual increase in activity suggests long-term changes in the magma body or changes in the hydrothermal cracking front. Preliminary analysis and event counts for the 2004-2005 deployment will be presented to assess whether or not the build up in activity seen in 2003-2004 continued. Numerous brief swarms are observed throughout the deployment and their locations will be studied relative to temporal changes in the vent temperature monitoring as well as variations in the fluid chemistry (see Von Damm et al., same session). Early analysis suggests two dominant areas of recurrent activity, between M-vent and Bio-9 and between Bio-9 and Tube-worm pillar. The exceptionally well-characterized and monitored seafloor at this site allows for unprecedented correlation of observed seismic activity with local biology, geology, geochemical and hydrothermal monitoring. As results from different monitoring activities continue to come in, a detailed understanding of the linkages should emerge.

Dopant disorder-free 2DEG GaAs/AlGaAs heterostructure FET devices for quantum hall and nanostructure studies

International Nuclear Information System (INIS)

Facer, G.R.; Kane, B.E.

1996-01-01

Full text: Two-dimensional electron gas (2DEG) GaAs/AIGaAs heterostructures have been grown by molecular beam epitaxy (MBE) in which gate-induced accumulation of carriers replaces the more usual modulation doping. These novel devices have the advantages of reduced disorder and a high degree of tunability in the carrier density. Because modulation doping is not used, disorder effects in the 2DEG due to nearby dopants are eliminated. Mean free paths for electrons exceed 30 μm at low temperatures. Electron densities are accurately tunable over nearly two orders of magnitude, from 9 x 10 9 cm -2 to 4 x 10 11 cm -2 . Very high electron mobilities, exceeding 3 x10 6 cm 2 /Vs at 4.2 K, are obtained. With such a combination of density tunability and low disorder, these layers provide unique opportunities for studying low dimensional systems following further lithography. Nanolithography with feature sizes under 50 nm will be possible at UNSW in early 1996. In preparation for 1-dimensional and 0-dimensional structure fabrication, the 2DEG samples have been characterised in steady fields at temperatures ∼ 50 mK. Recent theory has explained the fractional quantum Hall effect at electron filling factor ν=1/2 in terms of composite fermions (made up of interacting electrons) behaving as if they are a non-interacting system at B=0. The question of the mobility μ c of composite fermions in the new devices, and how it varies as the electron density varies, has been studied. Preliminary measurements at ν=1/2 yield μ c ∼ 10 4 cm 2 /Vs. The composite fermion mobility is nearly independent of electron density beyond an apparent threshold N = 0.5 x 10 11 cm -2 , and independent of temperature in the range 50 to 200 mK. The electron N threshold coincides with the crossover of the carrier Fermi wavelength and the mean free path

Acetanilide interaction with hydriodic acid in aqueous solutions at 20 and 40 deg C

International Nuclear Information System (INIS)

Erkasov, R.Sh.; Nurakhmetov, N.I.

1990-01-01

Isothermal method was used to study acetanilide solubility in aqueous solutions of hydriodic acid at 20 and 40 deg C. formation of two new anhydrous compounds of 2:1 and 1:1 compositions (anilide: acid molar ratio) was established. Temperature and concentration boundaries of solid phase formation were established for these compounds. Their IR spectroscopic investigation was conducted

Environmental Fatigue Behaviors of CF8M Stainless Steel in 310 .deg. C Deoxygenated Water - Effects of Hydrogen and Microstructure

Energy Technology Data Exchange (ETDEWEB)

Jang, Hun; Cho, Pyungyeon; Jang, Changheui [KAIST, Daejeon (Korea, Republic of); Kim, Tae Soon [Korea Hydro and Nuclear Power Corporation, Seoul (Korea, Republic of)

2014-01-15

The effects of environment and microstructure on low cycle fatigue (LCF) behaviors of CF8M stainless steels containing 11% of ferrites were investigated in a 310 .deg. C deoxygenated water environment. The reduction of LCF life of CF8M in a 310 .deg. C deoxygenated water was smaller than 316LN stainless steels. Based on the microstructure and fatigue surface analyses, it was confirmed that the hydrogen induced cracking contributed to the reduction in LCF life for CF8M as well as for 316LN. However, many secondary cracks were found on the boundaries of ferrite phases in CF8M, which effectively reduced the stress concentration at the crack tip. Because of the reduced stress concentration, the accelerated fatigue crack growth by hydrogen induced cracking was less significant, which resulted in the smaller environmental effects for CF8M than 316LN in a 310 .deg. C deoxygenated water.

MODIS/Terra Aerosol Cloud Water Vapor Ozone Monthly L3 Global 1Deg CMG V006

Data.gov (United States)

National Aeronautics and Space Administration — MODIS/Terra Aerosol Cloud Water Vapor Ozone Monthly L3 Global 1Deg CMG (MOD08_M3). MODIS was launched aboard the Terra satellite on December 18, 1999 (10:30 am...

MODIS/Terra Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG V006

Data.gov (United States)

National Aeronautics and Space Administration — MODIS/Terra Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG (MOD08_D3). MODIS was launched aboard the Terra satellite on December 18, 1999 (10:30 am equator...

MODIS/Aqua Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG V006

Data.gov (United States)

National Aeronautics and Space Administration — MODIS/Aqua Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG (MYD08_D3). MODIS was launched aboard the Aqua satellite on May 04, 2002 (1:30 pm equator...

Biological effects of diethylene glycol (DEG) and produced waters (PWs) released from offshore activities: a multi-biomarker approach with the sea bass Dicentrarchus labrax.

Science.gov (United States)

Stefania, Gorbi; Maura, Benedetti; Claudia, Virno Lamberti; Barbara, Pisanelli; Ginevra, Moltedo; Francesco, Regoli

2009-11-01

Diethylene glycol (DEG) is largely used during oil and gas exploitation by offshore platforms. The aim of this work was to investigate if this compound induces direct molecular/cellular effects in marine organisms, or indirectly modulate those of produced waters (PWs). Sea bass (Dicentrarchus labrax) were exposed to DEG dosed alone or in combination with PWs from an Adriatic platform. A wide array of analysed biomarkers included cytochrome P450-dependent enzymatic activity, bile metabolites, glutathione S-transferases, acetylcholinesterase, peroxisomal proliferation, antioxidant defences (catalase, glutathione reductase, glutathione peroxidases, glutathione), total oxyradical scavenging capacity, malondialdehyde and DNA integrity (single strand breaks and frequency of micronuclei). Results did not reveal marked effects of DEG, while PWs influenced the biotransformation system, the oxidative status and the onset of genotoxic damages. Co-exposures caused only limited differences of biomarker responses at some experimental conditions, overall suggesting a limited biological impact of DEG at levels normally deriving from offshore activities.

A Byzantine chant collection from Sicily: a collaboration between Copenhagen and Piana degli Albanesi (Palermo)

DEFF Research Database (Denmark)

Sanfratello, Giuseppe

2016-01-01

The aim of this paper is to give an account of the collaboration between a collector of the Byzantine chant tradition of Piana degli Albanesi (Palermo) in Sicily, namely fr. Bartolomeo Di Salvo, and the editorial board of the Monumenta Musicae Byzantinae, i.e. an institution under the aegis...

Identification of ultra-fine Ti-rich precipitates in V-Cr-Ti alloys irradiated below 300 deg. C by using positron CDB technique

International Nuclear Information System (INIS)

Fukumoto, Ken-ichi; Matsui, Hideki; Ohkubo, Hideaki; Tang, Zheng; Nagai, Yasuyoshi; Hasegawa, Masayuki

2008-01-01

Irradiation-induced Ti-rich precipitates in V-Ti and V-4Cr-4Ti alloys are studied by TEM and positron annihilation methods (positron lifetime, and coincidence Doppler broadening (CDB)). The characteristics of small defect clusters formed in V alloys containing Ti at irradiation temperatures below 300 deg. C have not been identified by TEM techniques. Strong interaction between vacancy and Ti solute atoms for irradiated V alloys containing Ti at irradiation temperatures from 220 to 350 deg. C are observed by positron lifetime measurement. The vacancy-multi Ti solute complexes in V-alloys containing Ti are definitely identified by using CDB measurement. It is suggested that ultra-fine Ti-rich precipitates or Ti segregation at periphery of dislocation loops are formed in V alloys containing Ti at irradiation temperatures below 300 deg. C

Irradiations under magnetic field. Measurement of resistivity sample irradiations between 100 and 500 deg C in a swimming-pool reactor

International Nuclear Information System (INIS)

Pauleve, J.; Marchand, A.; Blaise, A.

1964-01-01

An oven is described which enables the irradiation of small samples in the maximum neutron flux of a swimming-pool reactor of 15 MW (Siloe), at temperatures of between 100 and 500 deg.C defined to ± 0,5 deg.C, The oven is very simple from the technological point of view, and has a diameter of only 27 mm, This permits resistivity measurements to be carried out under irradiation in the reactor, or as another example, it enables irradiations in a magnetic field of 5000 oersteds, created by an immersed solenoid. (authors) [fr

La ballata E5 e le sue varianti nel codice degli abbozzi

Directory of Open Access Journals (Sweden)

Giulia Ravera

2016-07-01

Full Text Available La ballata petrarchesca Amor, che ’n cielo e ’n cor gentile alberghi (E5, composta per il musico Confortino e destinata alla definitiva esclusione dal Canzoniere, è un componimento profondamente complesso, oltre che caratterizzato da un’intrigante vicenda redazionale. E5 appare infatti imperniata sull’ambiguità tra due poli opposti, amoroso e religioso, in un gioco di contrapposizioni che rende difficile scegliere in via definitiva tra un’interpretazione sentimentale ed una lettura morale o addirittura penitenziale. La ballata è inoltre caratterizzata dall’evidente ed esteso riuso della tradizione lirica ed in particolare dei modelli stilnovistici, non solo e non tanto sul piano degli stilemi e delle immagini, quanto in termini di concezione amorosa. Il rapporto con queste fonti risulta problematico, tra ripresa e negazione, e rappresenta un ulteriore nodo significativo rispetto all’interpretazione del componimento. La graduale evoluzione della ballata, di cui possono essere identificate per lo meno tre versioni distinte, sembra accentuare gli elementi di complessità e le sovrapposizioni semantiche. Infine, l’analisi formale e contenutistica di E5 favorisce la formulazione, pur senza pretesa di certezza, di ipotesi sulle ragioni della sua sorte extravagante

Research into zirconium alloys resistant to carbon dioxide under pressure at temperatures of up to 600 deg C (1963); Recherche d'alliages de zirconium compatibles avec le gaz carbonique sous pression jusqu'a 500 ou 600 deg C (1063)

Energy Technology Data Exchange (ETDEWEB)

Baque, P; Dominget, R; Bossard, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-07-01

Zirconium is a metal having a relatively low neutron capture cross-section and a high melting point; it is thus possible to consider its use in particular as a canning material for fuel elements in CO{sub 2}-cooled nuclear reactors. A preliminary study of several types of zirconium showed that the metal is already strongly oxidised in this gas at 500 deg C. The 'breakaway' phenomenon is generalised; the oxidation rate is then linear and depends on the carbon dioxide pressure. An attempt was therefore made to find binary and tertiary alloys in order to improve the metal behaviour. Several interesting compositions were found: 1, 1.6 and 2.5 per cent of copper, 2 per cent of vanadium, and 0.05 and 0.5 per cent of calcium. Tertiary copper-molybdenum and copper-phosphorus alloys are also less liable to oxidation and in particular do not exhibit the 'breakaway' phenomenon even after a prolonged treatment at 600 deg C. (authors) [French] Le zirconium se trouve parmi les metaux a section de capture neutronique relativement faible et possede une temperature de fusion elevee; aussi peut on songer a l'employer notamment comme materiau de gainage d'elements combustibles pour reacteurs nucleaires refroidis au gaz carbonique. Une etude prealable de plusieurs qualites de zirconium a montre que le metal est deja assez fortement oxyde dans ce gaz des 500 deg C. En effet, le phenomene de ''breakaway'' est general; la vitesse d'oxydation devient alors lineaire et depend de la pression du gaz carbonique. La recherche d'alliages binaires et ternaires a donc ete entreprise afin de tenter d'ameliorer le comportement du metal. Elle a permis d'aboutir a quelques compositions interessantes: cuivre 1, 1,6 et 2,5 pour cent, vanadium 2 pour cent, et calcium 0,05 et 0,5 pour cent. Des alliages ternaires au cuivre-molybdene et cuivre-phosphore sont egalement moins oxydables, et en particulier ne presentent pas le phenomene de ''breakaway'', meme apres une longue exposition a 600 deg C. (auteurs)

Experimental determination of the phase relationships in Zr/2.5-8.0 at% Nb/0-6.7 at% Al alloys with 750 at ppm O and 250 at ppm N between 730-900deg C

International Nuclear Information System (INIS)

Peruzzi, A.; Bolcich, J.

1990-01-01

Zr alloys with 2.5 to 8.0 at% Nb and 0 to 6.7 at% Al were subjected to dynamic and static treatments between 730-900deg C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zn-Nb-Al alloys with 750 atppm O and 250 atppm N are the following: (i) Equilibrium relationships are established between the α (hcp), β (bcc) and Zr 3 Al (Cu 3 Au) phases along isothermal sections at 730, 771 and 800deg C. (ii) The β/α+β boundaries are determined along iso-aluminum vertical sections at 6.7, 3.3 and 0 at% Al. (iii) The addition of Al to Zr-Nb alloys increases the solubility of Nb in the α phase, its maximum value at 730deg C being about 0.7-0.8 at% for 4 at% Al.(iv) Solubility values for Al in the α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy in the Zr-Al system. (orig.)

Selecting Eco-Friendly Thermal Systems for the “Vittoriale Degli Italiani” Historic Museum Building

Directory of Open Access Journals (Sweden)

Davide Astiaso Garcia

2015-09-01

Full Text Available Thermal systems installed in museums should guarantee the maintenance of the optimal hygrothermal parameters ranges for the conservation of their collection materials. Considering the preservation of historic buildings, according to their historical and landscaping constraints, not all the thermal system typologies could be installed in these buildings’ typologies. Therefore, the main aim of this paper is to present some indications for the choice of the best thermal system solutions for a considered historic museum building, called Vittoriale degli Italiani, in the north of Italy, taking into account their installation feasibility and their related environmental impacts. The methodology includes a monitoring of the current hygrothermal parameters as well as the assessment of design heat and cooling loads related to the maintenance of the optimal hygrothermal parameters ranges for the conservation of collection materials. In addition, a Life Cycle Assessment (LCA of each selected system typology is considered for highlighting the most eco-friendly solution among the suitable ones. The obtained results highlights the feasible thermal system solutions able to maintain the hygrothermal parameters between the optimal ranges with a lower environmental impact in the Vittoriale degli Italiani historic museum building.

Giant magnetic quadrupole resonance studied with 180 deg. electron scattering

CERN Document Server

Neumann-Cosel, P V

1999-01-01

The nuclei sup 4 sup 8 Ca and sup 9 sup 0 Zr were investigated in 180 deg. high-resolution inelastic electron scattering for momentum transfers q approx =0.35-0.8 fm sup - sup 1. Complete M2 strength distributions could be extracted in both nuclei up to excitation energies of about 15 MeV utilizing a fluctuation analysis technique. Second-RPA calculations successfully describe the experimentally observed strong fragmentation of the M2 mode. The quenching of the spin part is found to be comparable to the M1 case, contrary to previous claims suggesting a stronger reduction. A quantitative reproduction of the data requires the presence of appreciable orbital strength which can be interpreted as a torsional elastic vibration (the so-called twist mode).

Investigation of effect of air flow rate on Zircaloy-4 oxidation kinetics and breakaway phenomenon in air at 850 .deg. C

International Nuclear Information System (INIS)

Maeng, Yunhwan; Lee, Jaeyoung; Park, Sanggil

2016-01-01

This paper analyzed an effect of flow rate on oxidation kinetics of Zircaloy-4 in air at 850 .deg. C. In case of the oxidation of Zircaloy-4 in air at 850 .deg. C, acceleration of oxidation kinetics from parabolic to linear (breakaway phenomenon) occurs. Oxidation and breakaway kinetics of the Zircaloy-4 in air was experimentally studied by changing a flow rate of argon/air mixture. Tests were conducted at 850 .deg. C under constant ratio of argon and air. The effects of flow rate on the oxidation and breakaway kinetics was observed. This paper is based on a revised and considerably extended presentation given at the 21 st International Quench Workshop. The effects of flow conditions on the oxidation kinetics of Zircaloy-4 samples were explained with residence time and percent flow efficiency. In addition, several issues were observed from this study, interdiffusion at breakaway and deformation of oxide structure by breakaway phenomenon

The Solar Neighborhood. XXV. Discovery of New Proper Motion Stars with 0.40 sec/yr > mu > or = 0.18 sec/yr Between Declinations -47 deg and 00 deg

Science.gov (United States)

Boyd, Mark R.; Winters, Jennifer G.; Henry, Todd J.; Jao, Wei-Chun; Finch, Charlie T.; Subasavage, John P.; Hambly, Nigel C.

2011-01-01

We present 2817 new southern proper motion systems with 0.40 sec/yr > mu > or = 0.18 sec/yr and declination between 47 deg and 00 deg. This is a continuation of the SuperCOSMOS-RECONS (SCR) proper motion searches of the southern sky. We use the same photometric relations as previous searches to provide distance estimates based on the assumption that the objects are single main-sequence stars. We find 79 new red dwarf systems predicted to be within 25 pc, including a few new components of previously known systems. Two systems--SCR 1731-2452 at 9.5 pc and SCR 1746-3214 at 9.9 pc--are anticipated to be within 10 pc. We also find 23 new white dwarf (WD) candidates with distance estimates of 15-66 pc, as well as 360 new red subdwarf candidates. With this search, we complete the SCR sweep of the southern sky for stars with mu > or = 0.18 sec/yr and R(sub 59F) < or = 16.5, resulting in a total of 5042 objects in 4724 previously unreported proper motion systems. Here we provide selected comprehensive lists from our SCR proper motion search to date, including 152 red dwarf systems estimated to be within 25 pc (9 within 10 pc), 46 WDs (10 within 25 pc), and 598 subdwarf candidates. The results of this search suggest that there are more nearby systems to be found at fainter magnitudes and lower proper motion limits than those probed so far.

Characterizing concentrations of diethylene glycol and suspected metabolites in human serum, urine, and cerebrospinal fluid samples from the Panama DEG mass poisoning.

Science.gov (United States)

Schier, J G; Hunt, D R; Perala, A; McMartin, K E; Bartels, M J; Lewis, L S; McGeehin, M A; Flanders, W D

2013-12-01

Diethylene glycol (DEG) mass poisoning is a persistent public health problem. Unfortunately, there are no human biological data on DEG and its suspected metabolites in poisoning. If present and associated with poisoning, the evidence for use of traditional therapies such as fomepizole and/or hemodialysis would be much stronger. To characterize DEG and its metabolites in stored serum, urine, and cerebrospinal fluid (CSF) specimens obtained from human DEG poisoning victims enrolled in a 2006 case-control study. In the 2006 study, biological samples from persons enrolled in a case-control study (42 cases with new-onset, unexplained AKI and 140 age-, sex-, and admission date-matched controls without AKI) were collected and shipped to the Centers for Disease Control and Prevention (CDC) in Atlanta for various analyses and were then frozen in storage. For this study, when sufficient volume of the original specimen remained, the following analytes were quantitatively measured in serum, urine, and CSF: DEG, 2-hydroxyethoxyacetic acid (HEAA), diglycolic acid, ethylene glycol, glycolic acid, and oxalic acid. Analytes were measured using low resolution GC/MS, descriptive statistics calculated and case results compared with controls when appropriate. Specimens were de-identified so previously collected demographic, exposure, and health data were not available. The Wilcoxon Rank Sum test (with exact p-values) and bivariable exact logistic regression were used in SAS v9.2 for data analysis. The following samples were analyzed: serum, 20 case, and 20 controls; urine, 11 case and 22 controls; and CSF, 11 samples from 10 cases and no controls. Diglycolic acid was detected in all case serum samples (median, 40.7 mcg/mL; range, 22.6-75.2) and no controls, and in all case urine samples (median, 28.7 mcg/mL; range, 14-118.4) and only five (23%) controls (median, urine diglycolic acid (both OR > 999; exact p sample results were excluded and two from the same case were averaged, yielding

Il movimento degli scioperi nel XX secolo

Directory of Open Access Journals (Sweden)

Maria Theresa Schorer Petrone

1983-06-01

Full Text Available Cella, Gian Primo (organizador. Il movimento degli scioperi nel XX secolo. Bologna, Società Editrice Mulino, 1979. (primeiro parágrado do texto "O movimento das greves no século XX" constitui o resultado de laboriosa pesquisa realizada por um grupo de sociólogos— Guido 13oglioni, Lorenzo Bordogna, Gian Primo Cella, Pietro Kemeny, Giancarlo Provasi, Guido Romagnoli e Gian Enrico Rusconi — ligados às universidades de Turim, Parma, Trento e Cagliari.  Analisando com técnicas de quantificação, os mais variados aspectos das greves ocorridas desde o início deste século até 1970 na Grã Bretanha, Alemanha, Itália, França e nos Estados Unidos, e considerando esses niovimentos' os indicadores mais significativos da ação operária enquanto Manifestação sindical e reinvindicativa, acreditavam que poderiam de-teCtar as relações entre ação operária e as 'mudanças sociais.  O livro em questão é o resultado da primeira fase desta pesquisa em que se procurou reconstruir os movimentos grevistas e suas formas, chegando-se a construir modelos explicativos .

Superconducting transition and low-field magnetoresistance of a niobium single crystal at 4.2 deg. K; Transition supraconductrice et magnetoresistance en champ faible d'un echantillon monocristallin de niobium a 4.2 deg. K

Energy Technology Data Exchange (ETDEWEB)

Perriot, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Service de physique du solide et de resonnance magnetique

1967-01-01

We report the study of the electrical resistance of a niobium single crystal, at 4.2 deg. K, from the beginning of the superconductive transition to 80 kilo oersteds. Critical fieldsH{sub c2} and H{sub c3} have been determined. Influences on superconductive transition of current density, field-current angle, crystal orientation and magnetoresistance have been studied. Variation laws of low-field transverse and longitudinal magneto-resistances have been determined. (author) [French] La variation de la resistance electrique d'un monocristal cylindrique de niobium a ete etudiee, a 4,2 deg. K, depuis le debut de la transition supraconductrice jusqu'a 80 kilooersteds. Les champs critiques H{sub c2} et H{sub c3} ont ete determines. On a etudie l'influence de la densite de courant, de l'angle champ-courant, de l'anisotropie cristalline et de la magnetoresistance sur la transition supraconductrice. Les lois de variation des magnetoresistances transversale et longitudinale ont ete determinees dans le domaine des champs faibles. (auteur)

Isothermal section of the Y-Co-V ternary system at 500 deg. C

International Nuclear Information System (INIS)

Wei, X.X.; Yan, J.L.; Du, H.W.; Wu, C.L.; Zhou, K.W.; Zhuang, Y.H.; Li, J.Q.

2011-01-01

Research highlights: → The isothermal section of the Y-Co-V system at 500 deg. C has been established. → Only one ternary compound YV x Co 12-x was found in this system and it exhibits a linear homogeneity range for 1.30 ≤ x ≤ 3.64. → The maximum solid solubilities of V in the compounds Y 2 Co 17 , Y 2 Co 7 , YCo 3 , YCo 2 and Y 3 Co are about 10, 1.0, 3.0, 4.0 and 4.0 at.%, respectively. - Abstract: The isothermal section of the Y-Co-V system at 500 deg. C has been investigated by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Only one ternary compound YV x Co 12-x with a homogeneity range of 1.30 ≤ x ≤3.64 was found in this system. The maximum solid solubilities of V in Y 2 Co 17 , Y 2 Co 7 , YCo 3 , YCo 2 and Y 3 Co are about 10.0, 1.0, 3.0, 4.0 and 4.0 at.% V, respectively. The compounds VCo and VCo 3 have a homogeneity range of 46-66 at.% V and 22-30 at.% V, respectively. The maximum solid solubility of Y in VCo is about 2.0 at.% Y.

LA FORMAZIONE DEGLI INSEGNANTI PER UNA EDUCAZIONE PLURILINGUE E INTERCULTURALE

Directory of Open Access Journals (Sweden)

Edoardo Lugarini

2012-07-01

Full Text Available Dalla la Guida per lo sviluppo e l’attuazione di curricoli per una educazione plurilingue e interculturale del Consiglio d’Europa è possibile trarre una serie di indicazioni per disegnare un profilo professionale e, di conseguenza, una serie di indicazioni per la formazione iniziale e in servizio dell’insegnate di lingua (L1, L2, LS. In questo intervento si suggeriscono, senza alcuna pretesa di esaustività, degli indicatori relativi alle competenze professionali che l’insegnante dovrebbe possedere per poter svolgere la sua attività nella scuola italiana di oggi in considerazione dei bisogni linguistici delle nuove generazioni e degli obiettivi linguistici proposti dal Consiglio d’Europa nell’ambito delle politiche educative orientate a favorire la mobilità, una più efficace comunicazione internazionale, il rispetto dell’identità e della diversità delle culture, a sviluppare l’educazione alla cittadinanza democratica ed europea. Dalle riflessioni condotte emerge la necessità di una formazione disciplinare e didattica articolata e complessa che renda l’insegnante “professionista riflessivo” e “ricercatore sperimentale”TRAINING TEACHERS FOR MULTILINGUISTIC, INTERCULTURAL EDUCATIONFrom the Council of Europe’s Guide for the development and implementation of curricula for multilingual and intercultural education, it is possible to draw a series of explicit or implicit characteristics for teachers, and consequently, a series of indications for initial and in-service language (L1, L2, FL teacher training. This paper offers a brief view of the professional competences teachers should possess in order to carry out their roles in Italian schools considering the linguistic needs of the young generations and the language objectives set out by the Council of Europe regarding education policies that promote mobility, more effective International communication and respect for cultural identity and diversity, in an effort to

Effect of bonding and bakeout thermal cycles on the properties of copper alloys irradiated at 350 deg. C

International Nuclear Information System (INIS)

Singh, B.N.; Eldrup, M.; Toft, P.; Edwards, D.J.

1997-02-01

Screening experiments were carried out to investigate the effect of bonding and bakeout thermal cycles on microstructure, mechanical properties and electrical resistivity of the oxide dispersion strengthened (GlidCop, CuAl-25) and the precipitation hardened (CuCrZr, CuNiBe) cooper alloys. Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime-ageing, and bonding thermal treatment followed by re-ageing and the reactor bakeout treatment at 350 deg. C for 100 h. Tensile specimens of CuAl-25 were given the heat treatment corresponding to the bonding thermal cycle. A number of heat treated specimens were neutron irradiated at 350 deg. C to a dose level of ∼ 0.3 dpa in the DR-3 reactor at Risoe. Both unirradiated and irradiated specimens with various heat treatments were tensile tested at 350 deg. C. The microstructure and electrical resistivity of these specimens were determined in the unirradiated as well as irradiated conditions. The post-deformation microstructure of the irradiated specimens was also investigated. The fracture surfaces of both unirradiated and irradiated specimens were examined. Results of these investigations are reported in the present report. The results are briefly discussed in terms of thermal and irradiation stability of precipitates and particles and irradiation-induced segregation, precipitation and recovery of dislocation microstructure. (au) 6 tabs., 24 ills., 9 refs

MODIS/Aqua Aerosol Cloud Water Vapor Ozone 8-Day L3 Global 1Deg CMG V006

Data.gov (United States)

National Aeronautics and Space Administration — MODIS/Aqua Aerosol Cloud Water Vapor Ozone 8-Day L3 Global 1Deg CMG (MYD08_E3). MODIS was launched aboard the Aqua satellite on May 04, 2002 (1:30 pm equator...

Pre- and post-irradiation properties of copper alloys at 250 deg. C following bonding and bakeout thermal cycles

International Nuclear Information System (INIS)

Singh, B.N.; Edwards, D.J.; Eldrup, M.; Toft, P.

1997-01-01

Screening experiments were carried out to investigate the effect of bonding and bakeout thermal cycles on microstructure, mechanical properties and electrical resistivity of the oxide dispersion strengthened (GlidCop, CuAl-25) and the precipitation hardened (CuCrZr, CuNiBe) copper alloys. Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime-ageing, and bonding thermal treatment followed by re-ageing and the reactor bakeout treatment at 350 deg. C for 100 h. Tensile specimens of CuAl-25 were given the heat treatment corresponding to the bonding thermal cycle. A number of heat treated specimens were neuron irradiated at 250 deg. C to a dose level of ∼ 0.3 dpa in the DR-3 reactor at Risoe. Both unirradiated and irradiated specimens with various heat treatments were tensile tested at 250 deg. C. The microstructure and electrical resistivity of these specimens were determined in the unirradiated as well as irradiated conditions. The post-deformation microstructure of the irradiated specimens was also investigated. The fracture surfaces of both unirradiated and irradiated specimens were examined. Results of these investigations are reported in the present report. The main effect of the bonding thermal cycle heat treatment was a slight decrease in strength of CuCrZr and CuNiBe alloys. The strength of CuAl-25, on the other hand, remained almost unaltered. The post irradiation tests at 250 deg. C showed a severe loss of ductility in the case of CuNiBe alloy. The irradiated CuAl-25 and CuCrZr specimens, on the other hand, exhibited a reasonable amount of uniform elongation. The results are briefly discussed in terms of thermal and irradiation stability of precipitates and particles and irradiation-induced segregation, precipitation and recovery of dislocation microstructure. (au) 7 tabs., 28 ills., 15 refs

The system Ba(H2PO4)2-Sr(H2PO4)2-H3PO4(30%)-H2O at 25, 40 and 60 deg C

International Nuclear Information System (INIS)

Taranenko, N.P.; Serebrennikova, G.M.; Stepin, B.D.; Oboznenko, Yu.V.

1982-01-01

The system Ba(H 2 PO 4 ) 2 -Sr(H 2 PO 4 ) 2 -H 3 PO 4 (30%)-H 2 O (25 deg C) belongs to eutonic type systems. Solubility isotherms of salt components at 40 and 60 deg C are calculated. Polytherms (25-60 deg C) of solubility of monosubstituted barium and strontium phosphates in 30-60% H 3 PO 4 are obtained. The value of cocrystallization coefficient of Sr 2 + and Ba(H 2 PO 4 ) 2 Dsub(Sr)=0.042+-0.005 remains stable in the temperature range of 25-60 deg C and concentrations 30-60% phosphoric acid at initial content [Sr 2 + ]=1x10 - 2 mass%

Phase equilibrium in the AgI-RbI-H2O system at 25 deg C

International Nuclear Information System (INIS)

Stepin, B.D.; Serebrennikova, G.M.; Sazikova, L.A.; Starikova, Z.A.

1977-01-01

The triple system of AgI-RbI-H 2 O at 25 deg C was studied by the isothermal method. The formation of the Rb 2 AgI 3 complex compound, which dissolves in water with decomposition, was established. A powder pattern of Rb 2 AgI 3 was indexed

Investigation of flow condition on the oxidation of Zircaloy-4 in air at 850 and 1100 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Maeng, Yun Hwan; Lee, Jae Young [Hangdong Global University, Pohang (Korea, Republic of); Park, Sang Gil [ACT Co. Ltd, Daejeon (Korea, Republic of)

2016-05-15

An oxidation behavior of the Zircaloy-4 was experimentally studied by varying a flow rate and partial pressure of air. Tests were conducted at two distinct temperatures in which a kinetic transition was occurred, or not: 850 .deg. C and 1100 .deg. C. The effects of flow rate and partial pressure of air was studied by a measurement of mass gain using thermogravimetric analyzer (TGA). After experiments, samples were observed with macrophotography and metallography using optical microscopy. The effect of flow rate and partial pressure of air were qualitatively analyzed with those methods. The effects of flow conditions on the oxidation kinetics of Zircaloy-4 samples were qualitatively studied. The flow rate and the partial pressure of air were changed and their effects was different when the temperature was changed.

Investigation of phase transformations of U2.5Zr7.5Nb and U3Zr9Nb alloys aging at 600 deg C

International Nuclear Information System (INIS)

Cantagalli, Natalia Mattar; Tanure, Leandro Paulo de Almeida Reis; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa

2009-01-01

Investigation has been made of the effects of high-temperature aging (600 deg C) on the phase transformations in the U2.5Zr7.5Nb and U3Zr9Nb alloys. These alloys have been produced with vacuum induction melting (VIM) furnace in cast ingots. The ingots were homogenized at 1000 deg C for 24 hours in vacuum of -4 torr, and cooled to room temperature at a rate of 3 deg C/min. Specimens from these homogeneous materials, cut in 3 mm high and 10 mm diameter, were reheated to γ phase at 850 deg C, for 1 hour, and aging at 600 deg C at different times from 0.5 to 24 hours. The phases decomposition were characterized by X-ray diffraction (XRD), metallographic, micro-probe analyze by energy dispersive spectrometry (EDS) and microhardness methods. It was verified that the decomposition of the δ phase proceeds in two steps. The first is a discontinuous precipitation of a lamellar two-phase aggregate composed of alpha solid solution and a metastable gamma phase. The metastable gamma phase has a constant composition at given temperature. After longer annealing, it decomposes eutectoidally into the equilibrium (α + δ 2 ) phases mixture. During this process a modification of the original lamellar microstructure takes place. The obtained metastable phases of these alloys of different compositions were analyzed in relation to their constitution, heat treatability and micrographic features and the results confronted with available distinct uranium alloys data from literature. (author)

Fatigue limit of Zircaloy-2 under variable one-directional tension and temperature 300 deg C; Granica zamora zircaloy-2, pri cisto jednosmerno promenljivom opterecenju (A=1) na zatezanje i temperaturi 300 deg C

Energy Technology Data Exchange (ETDEWEB)

Spasic, Z; Simic, G [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

1968-11-15

A vacuum chamber wad designed and constructed. It was suitable for study of materials at higher temperatures in vacuum or controlled atmospheres. Zircaloy-2 fatigue at 300 deg C in argon atmosphere was measured. Character of strain is variable one directional (A=1) tension. Obtained results are presented in tables and in the form of Veler's curve. The obtained fatigue limit was {sigma} - 15 kp/mm{sup 2}. The Locati method was allied as well and fatigue limit value obtained was 15,75 kp/mm{sup 2}. Error calculated in reference to the previous value obtained by classical methods was 5%. Konstruisana je i izvedena vakuum-komora koja se pokazala prikladna za izucavanje osobina materijala na povisenim temperaturama u vakuumu ili kontrolisanim atmosferama. Izvrseno je ispitivanje zamaranja Zircaloy-2 na temperaturi 300 deg C u atmosferi preciscenog argona. Karakter opterecenja je bio cisto jednosmerno promenljivo opterecenje (A=1) na zatezanje. Dobiveni rezultati su dati tabelarno i u obliku Velerove krive. Dobijena je granica zamora {sigma} = 15 kp/mm{sup 2}. Primenjen je i metod Locati-a za priblizno odredjivanje granice zamora i dobijena je vrednost 15,75 kp/mm{sup 2}. Greska u odnosu na prethodnu granicu zamora dobijenu klasicnim metodom iznosi 5% (author)

Studies of Redox Equilibria at Elevated Temperatures I. The Estimation of Equilibrium Constants and Standard Potentials for Aqueous Systems up to 374 deg C

Energy Technology Data Exchange (ETDEWEB)

Lewis, Derek

1969-07-01

A method is described for the estimation of equilibrium constants for aqueous systems at temperatures up to 374 deg C from entropy and free energy data for 25 deg C and data on the variation of heat capacity with temperature. Partial molal heat capacities of aqueous ions are estimated on the basis of the principle that, with suitably chosen standard states, the partial molal entropies of ions of a particular class at any given temperature are linearly related to the corresponding entropies at some reference temperature. The method suggested is compared with other methods, based on the Van't Hoff isobar and on an extension of the conventional scale of ionic free energy at 25 deg C, and the general dependence of aqueous equilibria on ionic heat capacity is considered.

Noble gases in basalt glasses from a Mid-Atlantic Ridge topographic high at 14deg N - geodynamic consequences

International Nuclear Information System (INIS)

Staudacher, T.; Sarda, P.; Richardson, S.H.; Allegre, C.J.; Sagna, I.; Dmitriev, L.V.

1989-01-01

We present a complete noble gas study of mid-oceanic ridge basalt glasses (MORB) from a small ridge segment, centered on an along-strike topographic elevation of the Mid-Atlantic Ridge at about 14deg N. We have found the highest 40 Ar/ 36 Ar ratio ever observed for a MORB glass, i.e. 28,150±330 for sample 2ΠD40, correlated with high 129 Xe/ 130 Xe ratios and the highest noble gas concentrations in a so-called popping-rock, labeled 2ΠD43. The latter sample displays a 4 He/ 40 Ar * ratio of 2.0-2.7, which is close to the production ratio in the mantle due to the radioactive decay of U, Th and K. Hence, this sample probably best represents the elemental noble gas ratios in the mantle, from which we have computed the 4 He concentration in the mantle source of MORB to be 1.5x10 -5 cm 3 STP g -1 . High 4 He/ 3 He ratios in two of the samples from the summit of the topographic high indicate the presence of a U, Th-rich component in the mantle source, possibly old subducted oceanic crust and/or sediments, which could originate in the so-called mesosphere boundary layer. (orig.)

Nuclear transparency in 90 deg.c.m. quasielastic A(p,2p) reactions

International Nuclear Information System (INIS)

Aclander, J.; Alster, J.; Kosonovsky, I.; Malki, A.; Mardor, I.; Mardor, Y.; Navon, I.; Piasetzky, E.; Asryan, G.; Barton, D.S.; Buktoyarova, N.; Bunce, G.; Carroll, A.S.; Gushue, S.; Makdisi, Y.I.; Roser, T.; Tanaka, M.; Averiche, Y.; Panebratsev, Y.; Shimanskiy, S.

2004-01-01

We summarize the results of two experimental programs at the Alternating Gradient Synchrotron of BNL to measure the nuclear transparency of nuclei measured in the A(p,2p) quasielastic scattering process near 90 deg. in the pp center of mass. The incident momenta varied from 5.9 to 14.4 GeV/c, corresponding to 4.8 2 2 . Taking into account the motion of the target proton in the nucleus, the effective incident momenta extended from 5.0 to 15.8 GeV/c. First, we describe the measurements with the newer experiment, E850, which had more complete kinematic definition of quasielastic events. E850 covered a larger range of incident momenta, and thus provided more information regarding the nature of the energy dependence of the nuclear transparency. In E850 the angular dependence of the nuclear transparency near 90 deg. and the nuclear transparency deuterons were studied. Second, we review the techniques used in an earlier experiment, E834, and show that the two experiments are consistent for the carbon data. E834 also determines the nuclear transparencies for lithium, aluminum, copper, and lead nuclei as well as for carbon. A determination of the (π + ,π + p) transparencies is also reported. We find for both E850 and E834 that the A(p,2p) nuclear transparency, unlike that for A(e,e ' p) nuclear transparency, is incompatible with a constant value versus energy as predicted by Glauber calculations. The A(p,2p) nuclear transparency for carbon and aluminum increases by a factor of two between 5.9 and 9.5 GeV/c incident proton momentum. At its peak the A(p,2p) nuclear transparency is ∼80% of the constant A(e,e ' p) nuclear transparency. Then the nuclear transparency falls back to a value at least as small as that at 5.9 GeV/c, and is compatible with the Glauber level again. This oscillating behavior is generally interpreted as an interplay between two components of the pN scattering amplitude; one short ranged and perturbative, and the other long ranged and strongly absorbed

Creep curve formularization at 950degC for Hastelloy XR

International Nuclear Information System (INIS)

Kaji, Yoshiyuki; Muto, Yasushi

1991-03-01

Creep tests under constant stress were conducted on a nickel-base heat-resistant alloy, Hastelloy XR, in air at 950degC. Minimum creep strain rate, time to the onset of tertiary creep and time to rupture were obtained as a function of applied stress. Then, a creep constitutive equation was made based on the Garofalo formula for primary and secondary creep and based on the Kachanov-Rabotnov formula for tertiary creep, which could represent fairly well the experimental creep deformation curves under the constant stress conditions. The creep deformation under the constant load condition corresponding to the stress increment was analysed using the creep constitutive equation and strain hardening law. Then the calculated creep strain showed slightly higher value than the experimental creep strain, and the calculated life was shorter than the experimental one. (author)

The accelerated oxidation of zircaloy-4 at 700∼900 .deg. C in high pressure steam

International Nuclear Information System (INIS)

Kim, K. P.; Park, K. H.

1999-01-01

To find the effect of pressure on the high temperature oxidation of zircaloy-4, an autoclave capable of measuring the degree of oxidation at high temperatures and high pressure was manufactured. The specimens used in experiments are commercially available Zircaloy-4 used in Kori nuclear power plants. All the measurements were done at 700∼900 .deg. C in steam. Pressure effects were noticed. The oxide thickness was much thicker in high pressure steam, comparing to that in the 1 atm steam. And, the higher is the steam pressure, the thicker becomes the oxide. The enhancement of oxide growth rate at 700∼900 .deg. C in high pressure steam is approximately propotion to the power of 1.0∼1.6 of the ratio of experimental steam pressure to critical steam pressure. There is a critical steam pressure above that the oxidation rate enhances. The critical steam pressure was measured as 30∼40 bar. The enhanced oxidation seems from the oxide cracking due to the tetragonal to monoclinic phase transformation at high pressure steam

Corrosion of titanium alloys in concentrated chloride solutions at temperature up to 160 deg C

International Nuclear Information System (INIS)

Ruskol, Yu.S.; Viter, L.I.; Balakin, A.I.; Fokin, M.N.

1982-01-01

Resistance of VT1-0 titanium and 4200, 4207 titanium alloys to pitting and total corrosion in chlorides of cadmium, potassium, nickel, ammonium, barium, calcium, lithium, magnesium in respect to pH value and temperature (120,140,160 deg C) is determined. The results obtained are presented as nomograms of stability. Possible reasons for corrosion behaviour of titanium in each of the chlorides are discussed

Creep-fatigue propagation of semi-elliptical crack at 650 deg. C in 316L(N) stainless steel plates with or without welded joints; Propagation de fissures semi-elliptiques en fatigue-fluage a 650 deg. C dans des plaques d'acier 316L(N) avec ou sans joints soudes

Energy Technology Data Exchange (ETDEWEB)

Curtit, F

2000-07-01

This study realised in LISN Laboratory of CEA Saclay, deals with the creep fatigue propagation of semi elliptical crack at the temperature of 650 deg C in 316L(N) stainless steel plates with or without welded joints. A vast majority of the studies on creep fatigue propagation models are based on specimen (CT) especially designed for crack propagation study. The PLAQFLU program performed in LISN laboratory deals with the application and adaptation of these models to complex crack shape, which are more representative of the cracks observed in industrial components. In this scope, we use propagation tests realised at the temperature of 650 deg C with wide plates containing semi elliptical defects. For some of them, the initial defect is machined in the middle of a welded joint, which constitute a privileged site for the crack initiation. The approach used in this study is based on global parameters of fracture mechanics. At first, tests on CT specimen are used in order to determine the propagation laws correlating the crack growth rate to the global parameters K or C{sup *}. These laws are then supposed to be intrinsic to our materials and are used to analysed the semi elliptical crack propagation. The analysis of the comportment of the crack during the hold time demonstrates the possibility to establish a correlation between the crack propagation both in the deepest and the surface point and the local value of C{sup *}. These correlations are coherent in the different points of the crack front for the different applied hold times, and they present a reasonably good agreement with the creep propagation law identified on CT specimen. The simulation of test performed on based metal specimen with a model of summation of both creep and pure fatigue crack growth gives acceptable results when the calculus of the simplified expression of C{sup *}{sub s} considers a continuous evolution of creep deformations rate during the all test. (author)

Experimental determination of the constitution and the phase relationships in Zr (2.5-8.0)at.%Nb (0-6.7)at.%Al alloys with 750at.ppm0 and 250at.ppmN, between 730-900 deg C

International Nuclear Information System (INIS)

Peruzzi Bardella, A.; Bolcich, J.C.

1990-01-01

Zr alloys with 2.5 to 8.0 at%Nb and 0 to 6.7 at%Al, were subjected to dynamic and static treatments between 730-900 deg C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zr-Nb-Al alloys with 750 at.ppm0 and 250 at.ppmN are the following: a) Equilibrium relationships are established between α (hcp), β (bcc) and Zr 3 Al (Cu 3 Au) phases along isothermal sections at 730, 771 and 800 deg C. b) β/α+β boundaries are determined along iso-aluminium vertical sections at 6.7, 3.3 and 0 at%Al. As for the first two iso-aluminium sections, the β/α+β equilibrium boundary corresponding to the binary Zr-Nb system is found to have a positive curvature, which is contrary to what has been reported in the literature. The increase in the Al content shifts the T β/α+β at a rate of 5.1 to 8.5 deg C/at.%Al, depending on Nb content. c) The addition of Al to Zr-Nb alloys increases the partial solubility of Nb in the α phase, its maximum value at 730 deg C being about 0.7-0.8 at% for 4 at%Al. d) Solubility values for Al in α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy on the Zr-Al system. (Author)

Anelastic deformation of Pb(Zr,Ti)O3 thin films by non-180 deg. ferroelectric domain wall movements during nanoindentation

International Nuclear Information System (INIS)

Alguero, M.; Bushby, A.J.; Reece, M.J.; Seifert, A.

2002-01-01

Lead zirconate titanate Pb(Zr,Ti)O 3 ferroelectric thin films show significant anelastic deformation when indented with spherical tipped indenters. Experiments on films with different Zr/Ti ratio and a mixed , preferred crystallographic orientation have shown that there is a good agreement between the anelastic deformation and the maximum strain achievable by non-180 deg. domain wall movement. An expected increase of the indentation stiffness of the films also accompanies the anelastic deformation because of the single crystal elastic anisotropy. All these observations seem to indicate that non-180 deg. ferroelectric domain wall movements occur under indentation stresses and cause anelasticity. Stresses for maximum anelastic deformation are compared with those for recently reported stress-induced depolarization

Hydrogen permeability, diffusivity, and solubility of SUS 316L stainless steel in the temperature range 400 to 800 .deg. C for fusion reactor applications

International Nuclear Information System (INIS)

Lee, S. K.; Kim, H. S.; Noh, S. J.; Han, J. H.

2011-01-01

Tritium permeation is one of the critical issues for the economy and safety of fusion power plants. As an initial step in tritium permeation research for fusion reactor applications, experiments were initiated by using hydrogen as a tritium substitute. An experimental system for hydrogen permeation and related behaviors in solid materials was designed and constructed. A continuous flow method was adopted with a capacity for high temperatures up to ∼1,000 .deg. C under ultra-high vacuums of ∼10 -7 Pa. The hydrogen permeation behavior in SUS 316L stainless steel was investigated in the temperature range from 400 .deg. C to 800 .deg. C. As a result, the permeability, diffusivity and solubility of hydrogen were determined. The results were compared with the previously existing reference data. Changes in the sample's surface morphology after the hydrogen permeation experiment are also addressed.

Reduction of CSF flow artifact in fast fluid attenuated inversion recovery MR imaging. Study of excitation width in 180deg inversion pulse

International Nuclear Information System (INIS)

Tsuchihashi, Toshio; Yoshizawa, Satoshi; Maki, Toshio; Kitagawa, Matsuo; Suzuki, Ken; Fujita, Isao

1998-01-01

A technique that increases slice thickness so that it becomes wider than the excitation width of the 180deg inversion pulse and in which TR is partitioned twice has been investigated with regard to fast FLAIR. This is a technique that reduces the flow artifact of CSF. It is thought that, with this technique, the flow artifact is reduced because the CSF that flows onto the slice reaches the null point. The cross talk effect of the 180deg inversion pulse appears as a high CSF signal. As a result, the number of slices needs to be partitioned two or three times before imaging. Thus the imaging time is doubled or tripled. Considering the cross talk effect of the 180deg inversion pulse and the imaging time needed for this technique, the optimal imaging technique would be one that uses an inversion pulse that is four times slice thickness plus slice space and for which the number of slices is partitioned twice. Furthermore, the null point of CSF was dependent on dividing TR in half. (author)

Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 8 deg to 90 deg. 2: Influence of horizontal tail location for Model D

Science.gov (United States)

Barnhart, B.

1982-01-01

The influence of horizontal tail location on the rotational flow aerodynamics is discussed for a 1/6-scale general aviation airplane model. The model was tested using various horizontal tail positions, with both a high and a low-wing location and for each of two body lengths. Data were measured, using a rotary balance, over an angle-of-attack range of 8 to 90 deg, and for clockwise and counter-clockwise rotations covering an Omega b/2V range of 0 to 0.9.

Fattori di crescita e recettori tirosin chinasici nelle neoplasie e displasie degli animali domestici

OpenAIRE

Muscatello, Luisa Vera

2016-01-01

La perdita della comunicazione cellulare può portare ad una crescita deregolata e dunque alla trasformazione neoplastica. Gli scopi dello studio di dottorato sono stati di individuare il rapporto funzionale di alcuni fattori di crescita (FC) e dei loro recettori (RTC) in tipi di neoplasie e displasie degli animali domestici, quali: 1. Amplificazione del proto-oncogene ERBB2 e sovra-espressione del RTC erb-b2. in tumori mammari della gatta. 2. Espressione di erb-b2, di recettori ormonal...

Photocurrent and photovoltage induced in a 2DEG under intense, pulsed THz radiation

International Nuclear Information System (INIS)

Lewis, R.A.; Xu, W.; Pellemans, H.P.M.; Langerak, C.J.G.M.

1999-01-01

Full text: Intense THz radiation emitted by FELIX (Free Electron Laser for Infrared eXperiments) induces both photovoltage and photocurrent signals in a high-mobility (μ = 2 x 10 6 cm 2 /V s), low-density (n e = 2 x 10 11 cm -2 ) GaAs/AlGaAs-based 2DEG. Within the ∼5 μs FELIX macropulse, there is a rapid response in the longitudinal voltage of a Hall-bar sample, reproducible between pulses. A large response continues well after the pulse; this long-time-scale behaviour varies between pulses if the current exceeds a critical value (which decreases with radiation intensity and magnetic field). Within the macropulse, the photovoltage varies with magnetic field, saturating at low field (<100 mT). The photocurrent shows a rapid, non-resonant response, evident at integral filling factors in both longitudinal and transverse data, and a slower, cyclotron resonant response, peaking at ∼390 μs after the FELIX pulse. No anisotropy in the resistivity under polarised radiation was found

Low cycle fatigue behaviour of neutron irradiated copper alloys at 250 and 350 deg. C. (ITER R and D Task no. T213)

International Nuclear Information System (INIS)

Singh, B.N.; Stubbins, J.F.; Toft, P.

2000-03-01

The fatigue behaviour of a dispersion strengthened and a precipitation hardened copper alloys was investigated with and without irradiation exposure. Fatigue specimens of these alloys were irradiated with fission neutrons in the DR-3 reactor at Risoe with a flux of ∼2.5 x 10 17 n/m 2 s (E> 1 MeV) to influence levels of 1.0 - 1.5 x 10 24 n/m 2 (E> 1 MeV) at 250 and 350 deg. C. These irradiations were carried out in temperature controlled rigs where the irradiation temperature was monitored and controlled continuously throughout the whole irradiation experiment. Both unirradiated and irradiated specimens were fatigue tested in vacuum at the irradiation temperatures of 250 and 350 deg. C in a strain controlled mode with a loading frequency of 0.5Hz. Post-fatigue microstructures were examined using transmission electron microscopy and the fracture surfaces were investigated using scanning electron microscope. The present investigations demonstrated that the fatigue life decreases with increasing temperature and that the exposure to neutron irradiation causes further degradation in fatigue life at both temperatures. These results are discussed in terms of the observed post-fatigue microstructures and the fracture surface morphology. Finally, the main conclusions and their implications are summarised. (au)

Structures of glide-set 90 deg. partial dislocation cores in diamond cubic semiconductors

International Nuclear Information System (INIS)

Beckman, S.P.; Chrzan, D.C.

2003-01-01

Two core reconstructions of the 90 deg. partial dislocations in diamond cubic semiconductors, the so-called single- and double-period structures, are often found to be nearly degenerate in energy. This near degeneracy suggests the possibility that both core reconstructions may be present simultaneously along the same dislocation core, with the domain sizes of the competing reconstructions dependent on temperature and the local stress state. To explore this dependence, a simple statistical mechanics-based model of the dislocation core reconstructions is developed and analyzed. Predictions for the temperature-dependent structure of the dislocation core are presented

Blue and red thermoluminescence of natural quartz in the temperature region from -196 to 400deg. C

International Nuclear Information System (INIS)

Hashimoto, Tetsuo; Yanagawa, Yuji; Yawata, Takashi

2007-01-01

Quartz samples of three different origins were γ-irradiated with 20kGy at room temperature or at the temperature of liquid nitrogen (-196 deg. C), and analyzed by on-line TL-emission spectrometry over two temperature ranges: above 200deg. C (high-temperature region) and -196 to 200deg. C (low-temperature region). The emission spectra in the high-temperature region could be separated into intense blue TL (BTL) or red TL (RTL) properties. All quartz samples displayed more or less both properties of BTL and RTL in the low temperature region, shifting the BTL-emission spectra towards violet. Particularly, volcanically originated quartz (RTL, Medeshima) showed highly complex BTL and RTL peaks in the low-temperature region, and a stronger simple RTL peak in the high temperature. These complex glow-curve peaks are considered to reflect the presence of many crystal defects and much content of impurities in the volcanically formed quartz. In the glow-curve measurements, Brazilian quartz (quartz-vein origin) gave weak RTL and intense BTL in the low-temperature range, followed by faint emission of BTL in the high-temperature side. On the other hand, the radiation-induced colored (CC) part of a Madagascan crystal rock slice (hydrothermal origin) showed intense BTL together with slight RTL in the low temperatures, followed by strong BTL and appreciable strength of RTL in the high temperatures. The BTL-emission pattern (TL-color image) of a Madagascan slice showed a complementary relationship between irradiations at liquid-nitrogen temperature and at room temperature. To explain these radiation-induced phenomena from quartz, hydrogen radicals and Li + ions, derived from radiolysis products of OH-related impurities, could operate to eliminate the BTL centers by recombination below the room temperature

MISTURAS VITAMÍNICAS NA REGENERAÇÃO DO MARACUJAZEIRO AMARELO (Passiflora edulis f. flavicarpa Deg.

Directory of Open Access Journals (Sweden)

Ribas Alessandra Ferreira

2002-01-01

Full Text Available Cotilédones obtidos a partir de sementes germinadas in vitro foram usados como explantes com o objetivo de avaliar o efeito de dois complexos vitamínicos e de duas concentrações de 6-benzilaminopurina (BAP na organogênese direta do maracujá amarelo (Passiflora edulis f. flavicarpa Deg.. Empregou-se o meio Murashige & Skoog (1962 suplementado com as vitaminas MS ou B5 (vitaminas de GAMBORG et al., 1968 e 1 ou 2 mg. -1 de BAP. Foram testados quatro tratamentos, sendo cada um constituído de 60 explantes. O experimento foi inteiramente casualizado, com dez repetições. Os dados, analisados pelo teste de Tukey, demonstraram que os meios de cultura suplementados com o complexo vitamínico B5 induziram gemas em mais de 70% dos explantes, obtendo-se até 8 brotos por explante, com um enraizamento superior a 90%. A análise de ploidia das plantas regeneradas indicou um número aparentemente normal de cromossomos típicos dessa espécie (2n=18

TOMS/Earth Probe UV Reflectivity Daily L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Earth Probe UV Reflectivity Daily L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. (The shortname for this Level-3...

Etch pit and γ' precipitate evolution in controlled Waspaloy microstructures aged at 725, 800 and 875 deg. C

International Nuclear Information System (INIS)

Kelekanjeri, V. Siva Kumar G.; Gerhardt, Rosario A.

2009-01-01

In this paper, controlled microstructures of Waspaloy were produced with the objective of studying the kinetic mechanisms that drive microstructural evolution during short-term aging. Three individual sets of controlled microstructures were produced by an initial solution-treatment at 1145 deg. C followed by aging-treatments at 725, 800 and 875 deg. C for times up to 263.5 h. The resulting microstructures varied markedly from one aging set to the next. The three sets of aged specimens were systematically characterized via microscopy (SEM and AFM), DC four-point probe resistivity and X-ray diffraction techniques. The occurrence of perfect polygonal etch-pit shapes in the solution-treated microstructures, which transformed upon aging first into corner-rounded shapes, followed by irregular shapes and eventual dissolution, was evidenced here. This phenomenon of transformation of etch-pit shapes appears to occur concurrently with gamma prime nucleation and growth. The formation mechanism of the etch-pits and subsequent microstructural evolution upon aging are discussed herein

Measurement of 0.8 and 1.5 GeV proton induced neutron production cross sections at 0deg

International Nuclear Information System (INIS)

Shigyo, Nobuhiro; Kunieda, Satoshi; Watanabe, Takehito; Ishibashi, Kenji; Satoh, Daiki; Meigo, Shin-ichiro

2004-01-01

Neutron-production double-differential cross sections at 0deg were measured for proton-induced reactions on Fe and Pb targets at 0.8 and 1.5 GeV. The experiment was performed at the π2 beam line of the 12 GeV proton synchrotron in High Energy Accelerator Research Organization (KEK). Neutrons were measured by time-of-flight technique with two different flight path lengths, i.e. 3.5 and 5.0 m at 0.8 and 1.5 GeV, respectively. NE213 liquid organic scintillators 12.7 cm in diameter and 12.7 cm in thickness were set at 0deg as neutron detector. For the improvement of the energy resolution, the scintillator was connected with three Hamamatsu H2431 photomultipliers 5.1 cm in diameter. The neutron detection efficiencies were obtained by the SCINFUL-QMD code. The experimental data were compared with the calculation results of the intranuclear-cascade-evaporation (INC/E) and the quantum-molecular-dynamics (QMD) models. (author)

Antonio Scarpa y su obra Saggio di osservazioni e d’esperienze sulle principali malattie degli occhi

Directory of Open Access Journals (Sweden)

Rolando Neri-Vela

2015-04-01

Full Text Available Antonio Scarpa fue un gran anatomista y cirujano del siglo xviii y principios del xix. Llamado «padre de la oftalmología italiana», escribió el Saggio di osservazioni e d’esperienze sulle principali malattie degli occhi, libro de gran valor científico y artístico.Scarpa describió varias partes del cuerpo humano, que tienen su nombre.

CTD data from the N. E. Atlantic 31N to 46N, July 1982 Discovery cruise 130

Energy Technology Data Exchange (ETDEWEB)

Saunders, P M

1983-01-01

Lists and graphs of CTD data obtained aboard RRS Discovery during July 1982 are presented. A series of 14 stations were occupied between approximate 31 deg N 24 deg W and 46 deg N 14 deg W in support of sound ranging trials. A further 20 stations were occupied in the vicinity of Discovery Gap, a channel for deep flow between the Madeira and Iberian basins near 37 deg 30 N 15 deg 30 W. All CTD data were reconciled with reversing thermometer measurements, and salinity and oxygen samples. Root mean square differences for pressure, temperature, salinity and oxygen were 7 dB, .012 deg C, .007 PSU and 0.3 ml/l in the depth interval 0 to 2,000 dB and 6 dB, .005 deg C, .003 PSU and .16 ml/l for depths 2,000 to 5,600 dB.

Measurements of Pu239:U235 fission ratio using foils at temperatures up to 400 deg. C

Energy Technology Data Exchange (ETDEWEB)

Carter, D H; Puckett, B J; Richards, A E [General Reactor Physics Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1964-05-15

The paper describes the use of activation foils for the measurement of Pu239:U235 fission ratios in subcritical lattices at temperatures up to 390 deg C. Counting techniques and the method of analysis of the results are described in detail and the results are compared with fission chamber measurements. (author) 4 refs., 6 figs., 7 tabs.

Creep-fatigue propagation of semi-elliptical crack at 650 deg. C in 316L(N) stainless steel plates with or without welded joints

International Nuclear Information System (INIS)

Curtit, F.

2000-01-01

This study realised in LISN Laboratory of CEA Saclay, deals with the creep fatigue propagation of semi elliptical crack at the temperature of 650 deg C in 316L(N) stainless steel plates with or without welded joints. A vast majority of the studies on creep fatigue propagation models are based on specimen (CT) especially designed for crack propagation study. The PLAQFLU program performed in LISN laboratory deals with the application and adaptation of these models to complex crack shape, which are more representative of the cracks observed in industrial components. In this scope, we use propagation tests realised at the temperature of 650 deg C with wide plates containing semi elliptical defects. For some of them, the initial defect is machined in the middle of a welded joint, which constitute a privileged site for the crack initiation. The approach used in this study is based on global parameters of fracture mechanics. At first, tests on CT specimen are used in order to determine the propagation laws correlating the crack growth rate to the global parameters K or C * . These laws are then supposed to be intrinsic to our materials and are used to analysed the semi elliptical crack propagation. The analysis of the comportment of the crack during the hold time demonstrates the possibility to establish a correlation between the crack propagation both in the deepest and the surface point and the local value of C * . These correlations are coherent in the different points of the crack front for the different applied hold times, and they present a reasonably good agreement with the creep propagation law identified on CT specimen. The simulation of test performed on based metal specimen with a model of summation of both creep and pure fatigue crack growth gives acceptable results when the calculus of the simplified expression of C * s considers a continuous evolution of creep deformations rate during the all test. (author)

Annealing studies of Zircaloy-2 cladding at 580-850 deg C

International Nuclear Information System (INIS)

Hindle, E.D.

1983-01-01

For fuel rod cladding it is important to determine if prior metallurgical condition combined with irradiation damage can influence high temperature deformation, because studies of such deformation are required to produce data for the cladding ballooning models which are used in analysing loss-of-coolant (LOCA). If the behaviour of all cladding conditions during a LOCA can be represented by, say, the annealed condition, then a great deal of experimental work on a multiplicity of cladding conditions can be avoided. By examining the metallographic structure and hardness, the present study determines the time required in the range 580 to 850 deg C for returning Zircaloy cladding to the annealed condition, so that for any transient a point can be specified where the material should have annealed. An equation has been derived to give this information. (author)

Delayed detached-eddy simulation of vortex breakdown over a 70 .deg. delta wing

International Nuclear Information System (INIS)

Son, Mi So; Sa, Jeong Hwan; Park, Soo Hyung; Byun, Yung Hwan; Cho, Kum Won

2015-01-01

To investigate the vortex breakdown over the ONERA70 delta wing at an angle-of-attack of 27 .deg., unsteady simulations were performed using Reynolds-averaged Navier-Stokes and Spalart-Allmaras delayed detached-eddy simulations. A low-diffusive preconditioned Roe scheme with third-order MUSCL interpolation scheme was applied, along with second-order dual-time stepping combined with diagonalized alternating direction implicit method for unsteady simulation. Vortex breakdown was investigated through an examination of total pressure loss, axial velocity, and axial vorticity around the primary vortex. Delayed dtached-eddy simulation provided good agreement with experimental data and predicted all physical phenomena related to vortex breakdown well.

Nucleation at the phase transition near 40 deg. C in MnAs nanodisks

International Nuclear Information System (INIS)

Jenichen, B.; Takagaki, Y.; Ploog, K. H.; Darowski, N.; Feyerherm, R.; Zizak, I.

2006-01-01

The phase transition near 40 deg. C of both as-grown thin epitaxial MnAs films prepared by molecular beam epitaxy on GaAs(001) and nanometer-scale disks fabricated from the same films is studied. The disks are found to exhibit a pronounced hysteresis in the temperature curve of the phase composition. In contrast, supercooling and overheating take place far less in the samples of continuous layers. These phenomena are explained in terms of the necessary formation of nuclei of the other phase in each of the disks independent from each other. The influence of the elastic strains in the disks is reduced considerably

Experimental study of the iron - smectite system in the presence of a solution at 80 at 300 deg

International Nuclear Information System (INIS)

Guillaume, D.

2002-04-01

One of the concepts proposed for the storage of nuclear wastes consists in the use of several confining barriers placed between the waste and the biosphere. Vitrified wastes are placed in steel containers surrounded by compacted smectite (engineered barrier). The whole is placed in the geological deep site (geological barrier, granite or argilite). The prediction of the evolution of the performances of the engineered barrier (low permeability, high swelling and sorption capacities) necessitates the study of the long-term stability of its mineral constituents under the conditions of the repository. The aim is to determine the nature and the chemistry of potential newly-formed phases resulting from the temperature increase due to disintegration reactions of the wastes, the presence of fluids coming from the geological barrier, and from the liberation of iron due to the degradation of the containers. Natural systems (in particular geothermal systems and sedimentary basins) give information concerning the possible evolutions of clay minerals. However, the potential availability of metallic iron makes a particular case of the nuclear waste storage. The aim of this experimental study is to put to evidence the chemical and mineralogical transformations of the iron-clay system at 80 deg C and 300 deg C, in the presence of a solution, so as to predict the possible transformations of a bentonite placed in the deep storage conditions of radioactive wastes. Several sets of experiments were carried out to study the reactivity of the MX80 bentonite in the presence of a solution ([CI]=3.10 -2 molal, Na/Ca=5,5 and liquid/rock ratio of 10) in absence or in presence of iron (magnetite + hematite or iron + magnetite) at 80 deg C or 300 deg C, and over periods ranging from 1 day to 9 months. Run products were submitted to multi-technique and multi-scale characterisation: X-ray diffraction, scanning electron microscopy, transmission electron microscopy (HR imaging, EDS and EELS

OMI/Aura Surface UVB Irradiance and Erythemal Dose Daily L2 Global 0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The Version 003 of Aura-OMI Spectral Surface UVB Irradiance and Erythemal Dose Level-2G data product (Daily level-2 data binned into global 0.25 deg Lat/Lon grids)...

Inhibition between 350 and 500 deg. C of the corrosion of magnesium by damp air

International Nuclear Information System (INIS)

Darras, Raymond; Caillat, Roger

1960-01-01

It has been demonstrated that the formation of a fluoride layer on the surface of magnesium by either dry or wet methods raises the temperature to which it resists corrosion in damp air from 350 to 490 deg. C. This protection effect could lead to a revision of the Pilling and Bedworth rule. Reprint of a paper published in 'Comptes Rendus des Seances de l'Academie des Sciences', tome 249, p. 1517-1519, sitting of 19 October 1959 [fr

An in situ synchrotron energy-dispersive diffraction study of the hydration of oilwell cement systems under high temperature/autoclave conditions up to 130 deg. C

International Nuclear Information System (INIS)

Colston, Sally L.; Barnes, Paul; Jupe, Andrew C.; Jacques, Simon D.M.; Hall, Christopher; Livesey, Paul; Dransfield, John; Meller, Nicola; Maitland, Geoffrey C.

2005-01-01

The technique of synchrotron energy dispersive diffraction has been developed for in situ studies of cement hydration under autoclave conditions. This has been applied to oilwell cements hydrating at typical oilwell temperatures up to 130 deg. C. The results show clearly the detailed interplay between 11 detectable phases, from which a phase transformation scheme has been derived; this illustrates the progression of hydration up to 130 deg. C for two extreme cases, with and without conservation of water content and autoclave pressure. The monosulphate hydrate phases are found to exhibit different stability bounds, with a surprising sequence of the 14-water, 10-water then 12-water monosulphate as temperature/time increases; the latter form is particularly associated with conditions of water/pressure loss. The effect of retarders on C 3 S dissolution and CH formation is negligible above 70 deg. C, whereas the effect on the calcium sulphoaluminate hydrates is more complex, and possible reasons for this are discussed

Calcium aluminates hydration in presence of amorphous SiO2 at temperatures below 90 deg. C

International Nuclear Information System (INIS)

Rivas Mercury, J.M.; Turrillas, X.; Aza, A.H. de; Pena, P.

2006-01-01

The hydration behaviour of Ca 3 Al 2 O 6 , Ca 12 Al 14 O 33 and CaAl 2 O 4 with added amorphous silica at 40, 65 and 90 deg. C has been studied for periods ranging from 1 to 31 days. In hydrated samples crystalline phases like katoite (Ca 3 Al 2 (SiO 4 ) 3- x (OH) 4 x ) and gibbsite, Al(OH) 3 , were identified, likewise amorphous phases like Al(OH) x , calcium silicate hydrates, C-S-H, and calcium aluminosilicate hydrates, C-S-A-H, were identified. The stoichiometry of Ca 3 Al 2 (SiO 4 ) 3- x (OH) 4 x (0≤3-x≤0.334), which was the main crystalline product, was established by Rietveld refinement of X-ray and neutron diffraction data and by transmission electron microscopy. - Graphical abstract: Katoite, Ca 3 Al 2 (SiO 4 ) 3- x (OH) 4 x (0≤3-x≤0.334), was identified besides gibbsite, Al(OH) 3 , as a crystalline stable hydration products in Ca 3 Al 2 O 6 , Ca 12 Al 14 O 33 and CaAl 2 O 4 hydrated with added amorphous silica between 40 and 90 deg. C

TOMS/Earth Probe UV Aerosol Index Monthly L3 Global 1x1.25 deg Lat/Lon Grid V008

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National Aeronautics and Space Administration — This data product contains TOMS/Earth Probe UV Aerosol Index Monthly L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. (The shortname for this...

TOMS/Nimbus-7 UV Aerosol Index Monthly L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Nimbus-7 UV Aerosol Index Monthly L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. The Total Ozone Mapping...

TOMS/Earth Probe Total Column Ozone Daily L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Earth Probe Total Column Ozone Daily L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. (The shortname for this...

TOMS/Nimbus-7 Total Column Ozone Monthly L3 Global 1x1.25 deg Lat/Lon Grid V008

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National Aeronautics and Space Administration — This data product contains TOMS/Nimbus-7 Total Column Ozone Monthly L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. The Total Ozone Mapping...

TOMS/Nimbus-7 UV Aerosol Index Daily L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Nimbus-7 UV Aerosol Index Daily L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. The Total Ozone Mapping...

TOMS/Nimbus-7 Total Column Ozone Daily L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Nimbus-7 Total Column Ozone Daily L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. The Total Ozone Mapping...

A thermodynamic data base for Tc to calculate equilibrium solubilities at temperatures up to 300 deg C

Energy Technology Data Exchange (ETDEWEB)

Puigdomenech, I [Studsvik AB, Nykoeping (Sweden); Bruno, J [Intera Information Technologies SL, Cerdanyola (Spain)

1995-04-01

Thermodynamic data has been selected for solids and aqueous species of technetium. Equilibrium constants have been calculated in the temperature range 0 to 300 deg C at a pressure of 1 bar for T<100 deg C and at the steam saturated pressure at higher temperatures. For aqueous species, the revised Helgeson-Kirkham-Flowers model is used for temperature extrapolations. The data base contains a large amount of estimated data, and the methods used for these estimations are described in detail. A new equation is presented that allows the estimation of {Delta}{sub r}Cdeg{sub pm} values for mononuclear hydrolysis reactions. The formation constants for chloro complexes of Tc(V) and Tc(IV), whose existence is well established, have been estimated. The majority of entropy and heat capacity values in the data base have also been estimated, and therefore temperature extrapolations are largely based on estimations. The uncertainties derived from these calculations are described. Using the data base developed in this work, technetium solubilities have been calculated as a function of temperature for different chemical conditions. The implications for the mobility of Tc under nuclear repository conditions are discussed. 70 refs.

The 90deg excitation function for elastic 12C+12C scattering. The importance of Airy elephants

International Nuclear Information System (INIS)

McVoy, K.W.; Brandan, M.E.

1992-01-01

The 90deg excitation function for elastic 12 C+ 12 C scattering, at laboratory energies between the Coulomb barrier and 130 MeV, exhibits a complex structure of peaks and valleys whose nature has remained an unsolved mystery for more than 20 years. The problem has primarily been caused by the difficulty of choosing from a plethora of discretely ambiguous optical potentials. However, data accumulated above 150 MeV over the last decade have determined unique potentials at these higher energies, and the requirement of continuity downward in energy has recently permitted the determination of a unique set of potentials for angular distributions at energies below 130 MeV, where the excitation-function data exist. These new potentials are used to provide a mean-field (i.e., nonresonant) interpretation of the structure in the 12 C+ 12 C 90deg excitation function between 70 and 130 MeV. Its most prominent minima are found to be Airy minima from nuclear rainbows, with the remaining structure arising primarily from more elementary optical phenomena related to Fraunhofer diffraction. These same potentials are also successful in explaining the details of excitation functions measured very recently at other angles by Morsad. (orig.)

Superconducting transition and low-field magnetoresistance of a niobium single crystal at 4.2 deg. K

International Nuclear Information System (INIS)

Perriot, G.

1967-01-01

We report the study of the electrical resistance of a niobium single crystal, at 4.2 deg. K, from the beginning of the superconductive transition to 80 kilo oersteds. Critical fieldsH c2 and H c3 have been determined. Influences on superconductive transition of current density, field-current angle, crystal orientation and magnetoresistance have been studied. Variation laws of low-field transverse and longitudinal magneto-resistances have been determined. (author) [fr

The effect of high curing temperature on the reaction kinetics in MK/lime and MK-blended cement matrices at 60 deg. C

International Nuclear Information System (INIS)

Rojas, Moises Frias; Sanchez de Rojas, M.I.

2003-01-01

It is well known that the pozzolanic reaction between metakaolin (MK) and calcium hydroxide produces CSH, C 2 ASH 8 (stratlingite), C 4 AH 13 and C 3 ASH 6 (hydrogarnet). However, the presence or absence of these hydrated phases depends on different parameters, such as curing temperature, matrix used, etc. This paper shows the results of a study in order to know the effect of high curing temperature (60 deg. C) on the kinetics of the pozzolanic reaction in different matrices. MK/lime (calcium hydroxide) and MK-blended cement matrices were studied in samples stored and cured at 60 deg. C and up to 123 days of hydration. The nature, sequence and crystallinity of the hydrated phases were analysed using differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. Results showed that the sequence and formation of the hydrated phases was different in both matrices cured at 60 deg. C. In an MK/lime matrix, C 2 ASH 8 , C 4 AH 13 and C 3 ASH 6 were the main hydrated phases; while in an MK-blended cement, stratlingite was the sole hydrated phase issued from pozzolanic reaction. The DTA and XRD data also reveal an important fact: there is no evidence of the presence of hydrogarnet in blended cements

Research into zirconium alloys resistant to carbon dioxide under pressure at temperatures of up to 600 deg C (1963)

International Nuclear Information System (INIS)

Baque, P.; Dominget, R.; Bossard, J.

1963-01-01

Zirconium is a metal having a relatively low neutron capture cross-section and a high melting point; it is thus possible to consider its use in particular as a canning material for fuel elements in CO 2 -cooled nuclear reactors. A preliminary study of several types of zirconium showed that the metal is already strongly oxidised in this gas at 500 deg C. The 'breakaway' phenomenon is generalised; the oxidation rate is then linear and depends on the carbon dioxide pressure. An attempt was therefore made to find binary and tertiary alloys in order to improve the metal behaviour. Several interesting compositions were found: 1, 1.6 and 2.5 per cent of copper, 2 per cent of vanadium, and 0.05 and 0.5 per cent of calcium. Tertiary copper-molybdenum and copper-phosphorus alloys are also less liable to oxidation and in particular do not exhibit the 'breakaway' phenomenon even after a prolonged treatment at 600 deg C. (authors) [fr

δ-hydride habit plane determination in α-zirconium by strain energy minimization technique at 25 and 300 deg C

International Nuclear Information System (INIS)

Singh, R.N.; Stahle, P.; Sairam, K.; Ristmana, Matti; Banerjee, S.

2008-01-01

The objective of the present investigation is to predict the habit plane of δ-hydride precipitating in α-Zr at 25 and 300 deg C using strain energy minimization technique. The δ-hydride phase is modeled to undergo isotropic elastic and plastic deformation. The α-Zr phase was modeled to undergo transverse isotropic elastic deformation. Both isotropic plastic and transverse isotropic plastic deformations of α-Zr were considered. Further, both perfect and linear work-hardening plastic behaviors of zirconium and its hydride were considered. Accommodation strain energy of δ-hydrides forming in α-Zr crystal was computed using initial strain method as a function of hydride nuclei orientation. Hydride was modeled as disk with circular edge. The simulation was carried out using materials properties reported at 25 and 300 deg C. Contrary to several habit planes reported in literature for δ-hydrides precipitating in α-Zr crystal the total accommodation energy minima suggests only basal plane i.e. (0001) as the habit plane. (author)

Passing the Remote: Community and Television Viewing in Woobinda and La guerra degli Antò

OpenAIRE

Seger, Monica

2011-01-01

This paper explores television-modeled narratives in Silvia Ballestra’s La guerra degli Antò, of 1992, and Aldo Nove’s Woobinda, of 1996. In so doing, it considers both the role of a text's author and the majority/minority reception practices that lead to its social imprint. For a definition of reception practices it turns to the work of media and reception scholars such as Henry Jenkins and Ien Ang. Employing a soap-operatic narrative and respecting the viewing practices of a mi...

Cs2SeO4-UO2SeO4-H2O system at 25 deg C

International Nuclear Information System (INIS)

Serezhkina, L.B.; Serezhkin, V.N.

1987-01-01

Using the method of isothermal solubility at 25 deg C the interaction of cesium and uranyl selenates in aqueous solution is studied. Formation of congruently soluble Cs 2 UO 2 (SeO 4 ) 2 x2H 2 O and Cs 2 (UO 2 ) 2 x(SeO 4 ) 3 is ascertained, their crystallographic characteristics being determined

Granite - water interactions at 100 deg C, 50 MPa: an experimental study

International Nuclear Information System (INIS)

Savage, D.

1984-01-01

A monzogranite was reacted with water in hydrothermal solution equipment at 100 deg C, 50 MPa for 203 days, during which time six fluid samples were extracted at run temperature and pressure for chemical analysis. Fluid samples were analysed using ICP, INAA and standard wet chemical techniques and data are presented for 18 chemical species. Solids were examined using XRD and SEM. The high temperature speciation of the fluid phase chemistry was investigated using the geochemical software package EQ3/6. The evolution of the fluid phase chemistry is discussed in terms of mineral-fluid equilibria and the kinetics of mineral dissolution and precipitation reactions. The implications of these results to the modelling of the near-field geochemical environment of a high-level radioactive waste repository in granitic rock are discussed. (author)

Tropospheric profiles of nitrogen oxides, ozone, and other related trace species measured over the Atlantic near the west coast of Europe

Energy Technology Data Exchange (ETDEWEB)

Rohrer, F; Bruening, D; Grobler, E S; Koppmann, R; Kraus, A B; Schrimpf, W; Weber, M; Ehhalt, D H [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

1998-12-31

In June and December 1994, the concentrations of the nitrogen oxides NO, NO{sub 2} and NO{sub y} were measured together with ozone, photolysis frequency of NO{sub 2}, methane, CO, CO{sub 2}, PAN, and light hydrocarbons near the west coast of Europe above the Atlantic Ocean. Two vertical profiles for each season were obtained in the altitude range 1.5 to 12 km at four locations: near Prestwick (56 deg N, 9 deg W), Brest (49 deg N, 6 deg W), Faro (37 deg N, 12 deg W) and Tenerife (30 deg N, 18 deg W). The measured vertical profiles of NO are compared to the results of a low resolution 3-D chemical tracer model. (author)

Tropospheric profiles of nitrogen oxides, ozone, and other related trace species measured over the Atlantic near the west coast of Europe

Energy Technology Data Exchange (ETDEWEB)

Rohrer, F.; Bruening, D.; Grobler, E.S.; Koppmann, R.; Kraus, A.B.; Schrimpf, W.; Weber, M.; Ehhalt, D.H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

1997-12-31

In June and December 1994, the concentrations of the nitrogen oxides NO, NO{sub 2} and NO{sub y} were measured together with ozone, photolysis frequency of NO{sub 2}, methane, CO, CO{sub 2}, PAN, and light hydrocarbons near the west coast of Europe above the Atlantic Ocean. Two vertical profiles for each season were obtained in the altitude range 1.5 to 12 km at four locations: near Prestwick (56 deg N, 9 deg W), Brest (49 deg N, 6 deg W), Faro (37 deg N, 12 deg W) and Tenerife (30 deg N, 18 deg W). The measured vertical profiles of NO are compared to the results of a low resolution 3-D chemical tracer model. (author)

Buckling and reaction rate measurements in graphite moderated lattices fuelled with plutonium-uranium oxide clusters at temperatures up to 400 deg. C

International Nuclear Information System (INIS)

Carter, D.H.; Gibson, M.; King, D.C.; Marshall, J.; Puckett, B.J.; Richards, A.E.; Wass, T.; Wilson, D.J.

1965-07-01

The Report describes a series of experiments carried out in SCORPIO I and II on sub-critical graphite moderated lattices fuelled with 21-rod clusters of PuO 2 /UO 2 fuel. Three fuel batches with nominal plutonium: uranium ratios of 0.25%, 0.8% and 1.2% were investigated at temperatures between 20 deg. C and 400 deg. C. Because of the limited amounts of the three fuels, exponential measurements were made in 2-zone stacks, the outer regions of which were loaded with suitably matched 'reference fuel'. Fine structure distributions in the lattice cell were obtained with manganese and indium foils. Pu239/U235 fission ratios were determined both by fission chambers and by fission-product counting techniques. (author)

Systems of erbium chloride- carbamide- water and erbium nitrate- carbamide- water at 30 deg C

International Nuclear Information System (INIS)

Ajtimbetov, K.; Sulajmankulov, K.S.; Batyuk, A.G.; Ismailov, M.

1975-01-01

The systems erbium chloride - carbamide - water and erbium nitrate - carbamide - water were studied by solubility method at 30 deg C. In the system erbium chloride - carbamide - water three compounds were detected: ErClsub(3).6CO(NHsub(2))sub(2), ErClsub(3).4CO(NHsub(2))sub(2), ErClsub(3).2CO(NHsub(2))sub2.6Hsub(2)O. In the system erbium nitrate -carbamide - water two new compounds were found: Er(NOsub(3))sub(3).4CO(NHsub(2))sub2, Er(NOsub(3) )sub(3)

A Venus/Saturn Mission Study: 45deg Sphere-Cone Rigid Aeroshells and Ballistic Entries

Science.gov (United States)

Prabhu, Dinesh K.; Allen, Gary A.; Cappuccio, Gelsomina

2012-01-01

The present study considers ballistic entries into the atmospheres of Saturn and Venus using a 45deg sphere-cone rigid aeroshell (a legacy shape that has been successfully used in the Pioneer Venus and Galileo missions). For a number of entry mass and diameter combinations (i.e., various entries ballistic coefficients), entry velocities, and heading angles, the trajectory space in terms of entry flight path angles between skip out and -30deg is explored with a 3DOF trajectory code, TRAJ. Assuming that the thermal protection material of choice is carbon phenolic of flight heritage, the entry flight path angle space is constrained a posteriori by the mechanical and thermal performance parameters of the material. For mechanical performance, a 200 g limit is place on the peak deceleration load and 10 bar is assumed as the spallation pressure threshold for the legacy material. It is shown that both constraints cannot be active simultaneously. For thermal performance, a minimum margined heat flux threshold of 2.5 kW/sq cm is assumed for the heritage material. Using these constraints, viable entry flight path angle corridors are determined. Analysis of the results also hints at the existence of a "critical" ballistic coefficient beyond which the steepest possible entries are determined by the spallation pressure threshold. The results are verified against known performance of the various probes used in the Galileo and Pioneer Venus missions. It is hoped that the results presented here will serve as a baseline in the development of a new class of ablative materials for Venus and Saturn missions being considered in a future New Frontiers class of NASA missions.

The LiHCOO-Sc(HCOO)3-H2O system at 25 and 50 deg C

International Nuclear Information System (INIS)

Petrova, E.V.; Itkina, L.S.

1980-01-01

Solubility in the LiHCOO-Sc(HCOO) 3 -H 2 O system at 25 and 50 deg C has been investigated using the isothermal method It has been ascertainedy s stem is a simple eutonic one. Solubility isotherms consist of two crystallization branches: lithium formate monohydrate and scandium formate. Scandium formate salts-out lithium formate from the solution. Lithium formate increases the solubility of scandium formate (in the eutonic solution more than 2 times as compared to its solubility in the pure water)

A Transonic Wind-Tunnel Investigation of a Seaplane Configuration having a 40 Deg Sweptback Wing, TED No. NACA DE 387

Science.gov (United States)

Hieser, Gerald; Kudlacik, Louis; Gray, W. H.

1956-01-01

During the course of an aerodynamic loads investigation of a model of the Martin XP6M-1 flying boat in the.Langley 16-foot transonic tunnel, longitudinal-aerodynamic-performance information was obtained. Data were obtained at speeds up to and exceeding those anticipated for the seaplane in level flight and included the Mach number range from 0.84. to 1.09. The angle of attack was varied from -2deg to 6deg and the average Reynolds number, based on wing mean aerodyn&ic chord, was about 3.7 x 10(exp 6). This seaplane, although not designed to maintain level flight at Mach numbers beyond the force break, was found to have a transonic drag-rise coefficient of 0.0728, with an accompanying drag-rise Mach number of about 0.85. A large portion of the.drag rise and the relatively low value of drag-rise Mach number result from the axial coincidence of the maximum areas of the principal airplane components.

Spin Hall effect in a 2DEG in the presence of magnetic couplings

International Nuclear Information System (INIS)

Gorini, C; Schwab, P; Dzierzawa, M; Raimondi, R; Milletari, M

2009-01-01

It is now well established that the peculiar linear-in-momentum dependence of the Rashba (and of the Dresselhaus) spin-orbit coupling leads to the vanishing of the spin Hall conductivity in the bulk of a two-dimensional electron gas (2DEG). In this paper we discuss how generic magnetic couplings change this behaviour providing then a potential handle on the spin Hall effect. In particular we examine the influence of magnetic impurities and an in-plane magnetic field. We find that in both cases there is a finite spin Hall effect and we provide explicit expressions for the spin Hall conductivity. The results can be obtained by means of the quasiclassical Green function approach, that we have recently extended to spin-orbit coupled electron systems.

75 FR 81856 - Security Zone, Michoud Slip Position 30°0′34.2″ N, 89°55′40.7″ W to Position 30°0′29.5″ N, 89°55...

Science.gov (United States)

2010-12-29

...-AA87 Security Zone, Michoud Slip Position 30[deg]0'34.2'' N, 89[deg]55'40.7'' W to Position 30[deg]0'29.5'' N, 89[deg]55'52.6'' W AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The... position 30[deg]0'34.2'' N, 89[deg]55'40.7'' W to position 30[deg]0'29.5'' N, 89[deg]55'52.6'' W across the...

Diffusion and agglomeration of helium in stainless steel in the temperature range from RT to 600 deg. C

International Nuclear Information System (INIS)

Zhang, C.H.; Chen, K.Q.; Zhu, Z.Y.

2000-01-01

Diffusion of helium and formation of helium bubbles in stainless steel in conditions of atomic displacement in the temperature range from RT to 600 deg. C are studied theoretically using standard rate equations. The dissociative mechanism via self-interstitial/He replacement is assumed to control helium diffusion and bubble formation. The numerical analysis shows that the temperature dependence of the effective diffusion coefficient of helium, the number density and the mean radius of bubbles has two distinctly different regimes with the transition occurring around 300 deg. C. The effective diffusion coefficient of helium, the number density and the mean radius of bubbles show weak temperature dependence in the low temperature regime, while they change abruptly with temperature in the high temperature regime. The results are qualitatively in agreement with the results of our experimental study on helium diffusion and bubble formation in helium-implanted 316L stainless steel. However, the discrepancy in the absolute values of number density and mean radius of bubbles between theoretical and experimental studies indicates that helium diffusion and bubble formation may be controlled by some athermal mechanisms in the low temperature regime

Buckling and reaction rate measurements in graphite moderated lattices fuelled with plutonium-uranium oxide clusters at temperatures up to 400 deg. C

Energy Technology Data Exchange (ETDEWEB)

Carter, D H; Gibson, M; King, D C; Marshall, J; Puckett, B J; Richards, A E; Wass, T; Wilson, D J [General Reactor Physics Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1965-07-15

The Report describes a series of experiments carried out in SCORPIO I and II on sub-critical graphite moderated lattices fuelled with 21-rod clusters of PuO{sub 2}/UO{sub 2} fuel. Three fuel batches with nominal plutonium: uranium ratios of 0.25%, 0.8% and 1.2% were investigated at temperatures between 20 deg. C and 400 deg. C. Because of the limited amounts of the three fuels, exponential measurements were made in 2-zone stacks, the outer regions of which were loaded with suitably matched 'reference fuel'. Fine structure distributions in the lattice cell were obtained with manganese and indium foils. Pu239/U235 fission ratios were determined both by fission chambers and by fission-product counting techniques. (author) 14 refs, 30 figs, 18 tabs

Measurements of (n,xp), (n,xd) double differential cross sections of Al and C for neutrons at 75 and 65 MeV

Energy Technology Data Exchange (ETDEWEB)

Nauchi, Yasushi; Baba, Mamoru; Iwasaki, Tomohiko [Tohoku Univ., Sendai (Japan). Faculty of Engineering] [and others

1998-03-01

The (n,xp) and (n,xd) double differential cross sections (DDXs) of Al and C were measured at 6 angles (12deg, 17deg, 25deg, 40deg, 55deg and 70deg) for neutrons En=65 and 75 MeV. These data are compared with theoretical calculations of ISOBAR and GNASH. A new wide range spectrometer under fabrication to down the detection threshold is also described. (author)

Physicochemical properties of the CsNO2-CsOH-H2O ternary system at 25 deg C

International Nuclear Information System (INIS)

Protsenko, P.I.; Medvedev, B.S.; Popova, T.B.

1977-01-01

Saturated solutions of the CsNO 2 - CsOH- H 2 O system have been studied at 25 deg C by the methods of solubility, viscosity, electric conductivity, refractometry and density. It is stated that no solid phase of a new composition is formed in the system. While adding hydroxide to the saturated solution of cesium nitride, a considerable salting-out of the latter takes place

Fatigue limit of Zircaloy-2 under variable one-directional tension and temperature 300 deg C

International Nuclear Information System (INIS)

Spasic, Z.; Simic, G.

1968-11-01

A vacuum chamber wad designed and constructed. It was suitable for study of materials at higher temperatures in vacuum or controlled atmospheres. Zircaloy-2 fatigue at 300 deg C in argon atmosphere was measured. Character of strain is variable one directional (A=1) tension. Obtained results are presented in tables and in the form of Veler's curve. The obtained fatigue limit was σ - 15 kp/mm 2 . The Locati method was allied as well and fatigue limit value obtained was 15,75 kp/mm 2 . Error calculated in reference to the previous value obtained by classical methods was 5% [sr

75 FR 31677 - Amendment of Class E Airspace; Corpus Christi, TX

Science.gov (United States)

2010-06-04

... Jose Island Airport, TX (Lat. 27[deg]56'40'' N., long. 96[deg]59'06'' W.) Rockport, Aransas County... Meacham Blvd., Fort Worth, TX 76137; telephone (817) 321- 7716. SUPPLEMENTARY INFORMATION: History On... Corpus Christi, TX [Amended] Corpus Christi International Airport, TX (Lat. 27[deg]46'13'' N., long. 97...

Systems Li2B4O7 (Na2B4O7, K2B4O7)-N2H3H4OH-H2O at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Sadetdinov, Sh.V.; Akimov, V.M.; Mitrasov, Yu.N.; Petrova, O.V.; Klopov, Yu.N.

1994-01-01

Phase equilibriums in the Li 2 B 4 O 7 (Na 2 B 4 O 7 , K 2 B 4 O 7 )-N 2 H 3 H 4 OH-H 2 O systems were investigated by methods of isothermal solubility, refractometry and PH-metry at 25 deg C for the first time. Lithium and sodium tetraborates was established to form phases of changed composition mM 2 B 4 O 7 ·nN 2 H 3 C 2 H 4 OH·XH 2 O, where M=Li, Na with hydrazine ethanol. K 2 B 4 O 7 ·4H 2 O precipitates in solid phase in the case of potassium salt. Formation of isomorphous mixtures was supported by X-ray diffraction and IR spectroscopy methods

ELABORAZIONE DI UN QUESTIONARIO PER LA RILEVAZIONE DEI BISOGNI COMUNICATIVI DEGLI ADULTI IMMIGRATI

Directory of Open Access Journals (Sweden)

Annamaria Aquilino

2012-02-01

Full Text Available L’intensità del fenomeno migratorio in Italia suscita una riflessione critica sui bisogni linguistici di un  nuovo pubblico di apprendenti, spinti verso la conoscenza della lingua italiana da una forte esigenza di integrazione sociale. L’articolo presenta l’elaborazione di un questionario come strumento d’indagine essenziale per la rilevazione dei bisogni comunicativi degli immigrati adulti. Progettato nell’ambito di un corso di italiano L2  presso il CTP di Rozzano (Milano e sottoposto a un campione di 24 stranieri, il questionario si  è rivelato molto utile per la definizione del profilo dei singoli apprendenti e dell’intera classe che, caratterizzata da una grande differenziazione, non è sempre facile da gestire. L’interpretazione finale dei dati ha messo in luce non solo gli elementi di diversità ma ha anche permesso di cogliere alcuni tratti omogenei molto interessanti, indispensabili per la programmazione del percorso didattico, che sarà tanto efficace quanto più si adatterà alla realtà psicologica e socio-culturale degli apprendenti.     Questionnaire design to Survey the communicative needs of adult immigrants   Widespread immigration in Italy has brought about critical reflection on the linguistic needs of a new group of learners, highly motivated to learn the Italian language because of their strong need for social integration.  This article presents the designing of a questionnaire as an essential tool for surveying the communicative needs of adult immigrants.  Designed for an Italian L2 course held at the CTP in Rozzano (Milano and administered to 24 foreigners, the questionnaire was very useful for defining the profile of the single learners and the whole class group, which was dissimilar, and thus not the easiest to conduct.  The final interpretation of the data brought to light not only the elements of diversity but they also allowed us to recognize a few interesting common traits, essential for

Flight Investigation of the Low-Speed Characteristics of a 45 deg Swept-Wing Fighter-Type Airplane with Blowing Boundary-Layer Control Applied to the Leading- and Trailing-Edge Flaps

Science.gov (United States)

Quigley, Hervey C.; Anderson, Seth B.; Innis, Robert C.

1960-01-01

A flight investigation has been conducted to study how pilots use the high lift available with blowing-type boundary-layer control applied to the leading- and trailing-edge flaps of a 45 deg. swept-wing airplane. The study includes documentation of the low-speed handling qualities as well as the pilots' evaluations of the landing-approach characteristics. All the pilots who flew the airplane considered it more comfortable to fly at low speeds than any other F-100 configuration they had flown. The major improvements noted were the reduced stall speed, the improved longitudinal stability at high lift, and the reduction in low-speed buffet. The study has shown the minimum comfortable landing-approach speeds are between 120.5 and 126.5 knots compared to 134 for the airplane with a slatted leading edge and the same trailing-edge flap. The limiting factors in the pilots' choices of landing-approach speeds were the limits of ability to control flight-path angle, lack of visibility, trim change with thrust, low static directional stability, and sluggish longitudinal control. Several of these factors were found to be associated with the high angles of attack, between 13 deg. and 15 deg., required for the low approach speeds. The angle of attack for maximum lift coefficient was 28 deg.

Tropospheric mixing ratios of NO and NOy obtained during TROPOZ II in the latitude region 67 deg N-56 deg S

Energy Technology Data Exchange (ETDEWEB)

Rohrer, F.; Bruening, D.; Ehhalt, D.H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

1997-12-31

Tropospheric mixing ratios of NO and NOy were measured along the flight track of the TROPOZ II aircraft campaign. These measurements cover regions along the east coast of North America, the Pacific and Atlantic coast of South America and the Atlantic coast of North Africa and Europe. The meteorological conditions are close to the climatological mean: westerly winds at high and mid latitudes, variable and weak winds at low latitudes. (author) 2 refs.

Tropospheric mixing ratios of NO and NOy obtained during TROPOZ II in the latitude region 67 deg N-56 deg S

Energy Technology Data Exchange (ETDEWEB)

Rohrer, F; Bruening, D; Ehhalt, D H [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

1998-12-31

Tropospheric mixing ratios of NO and NOy were measured along the flight track of the TROPOZ II aircraft campaign. These measurements cover regions along the east coast of North America, the Pacific and Atlantic coast of South America and the Atlantic coast of North Africa and Europe. The meteorological conditions are close to the climatological mean: westerly winds at high and mid latitudes, variable and weak winds at low latitudes. (author) 2 refs.

The MgSeO4-UO2SeO4-H2O system at 25 deg C

International Nuclear Information System (INIS)

Serezhkina, L.B.; Serezhkin, V.N.

1984-01-01

The method of isothermal solubility at 25 deg C has been used to study MgSeO 4 -UO 2 SeO 4 -H 2 O system. Formation of the new compound Mg 2 (UO 2 ) 3 (SeO 4 ) 5 X32H 2 O, congruently soluble in water is stated. Thermographic and X-ray diffraction investigations of the prepared magnesium selenato-uranylate and products of its dehydration are conducted

La nuova disciplina del matrimonio degli stranieri alla luce del pacchetto sicurezza. I suoi riflessi sul matrimonio concordatario

Directory of Open Access Journals (Sweden)

Pierluigi Consorti

2011-02-01

Full Text Available SOMMARIO: 1. La capacità matrimoniale dello straniero prima del pacchetto sicurezza - 2. La novella dell’art. 116 c.c. - 3. Il diritto al matrimonio nel pacchetto sicurezza - 4. Art. 116 c.c. e matrimonio concordatario - 5. Pubblicazioni civili e matrimonio concordatario - 6. Trascrivibilità del matrimonio concordatario di cittadino straniero che non documenta la regolarità del soggiorno - 7. Matrimonio concordatario degli stranieri non cattolici - 8. Conclusione

OMI/Aura NO2 Cloud-Screened Total and Tropospheric Column Daily L3 Global 0.25deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-3 Global Gridded(0.25x0.25 deg) Nitrogen Dioxide Product "OMNO2d" is now released (Jan 10, 2013) to the public from the NASA Goddard Earth...

Silica enhanced formation of hydroxyapatite nanocrystals in simulated body fluid (SBF) at 37 deg. C

Energy Technology Data Exchange (ETDEWEB)

Sadjadi, M.S., E-mail: m.s.sadjad@gmail.com [Department of Chemistry, Sciences and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Ebrahimi, H.R. [Department of Chemistry, Sciences and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Meskinfam, M. [Department of Chemistry, Tonekabon Branch, Islamic Azad University, Tonekabon (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, University of Shahid Beheshti, Eveen Tehran (Iran, Islamic Republic of)

2011-10-17

Highlights: {yields} We report on fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in silica-containing simulated body fluid solution at 37 deg. C. {yields} Bioactivity and biodegradability of TCP precursor have been confirmed by the dissolution of TCP and formation of a bone like layer of new HA nanoparticles outside of the precursor after 24 h soaking in SBF solution. {yields} Successive nucleation and formation of tiny hexagonal HA nanoplates and nanorods have been confirmed by TEM results after 24 h soaking of TCP in silica-containing BSF solution. - Abstract: The chemical modification of implant (prosthesis) surfaces is being investigated worldwide for improving the fixation of orthopaedic and dental implants. The main goal in this surface modification approach is to achieve a faster bone growth and chemical bonding of the implant to the newly generated and/or remodeled bone. In this work, we report fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in simulated body fluid (SBF, inorganic components of human blood plasma) solutions at 37 deg. C, using calcium phosphate (TCP) and sodium silicate as precursors. Characterization and chemical analysis of the synthesized powders were performed by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated enhanced nucleation and formation of bone like layer of HA nanocrystals at the surface of TCP nanoparticles and occurrence of HA nanocrystals during 24 h soaking of TCP in SBF solution containing silica ions. The average size of a nanoparticle, using Scherrer formula, was found to be 18.2 nm.

Silica enhanced formation of hydroxyapatite nanocrystals in simulated body fluid (SBF) at 37 deg. C

International Nuclear Information System (INIS)

Sadjadi, M.S.; Ebrahimi, H.R.; Meskinfam, M.; Zare, K.

2011-01-01

Highlights: → We report on fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in silica-containing simulated body fluid solution at 37 deg. C. → Bioactivity and biodegradability of TCP precursor have been confirmed by the dissolution of TCP and formation of a bone like layer of new HA nanoparticles outside of the precursor after 24 h soaking in SBF solution. → Successive nucleation and formation of tiny hexagonal HA nanoplates and nanorods have been confirmed by TEM results after 24 h soaking of TCP in silica-containing BSF solution. - Abstract: The chemical modification of implant (prosthesis) surfaces is being investigated worldwide for improving the fixation of orthopaedic and dental implants. The main goal in this surface modification approach is to achieve a faster bone growth and chemical bonding of the implant to the newly generated and/or remodeled bone. In this work, we report fast formation of hexagonal nanocrystals of calcium hydroxyapatite (HA) in simulated body fluid (SBF, inorganic components of human blood plasma) solutions at 37 deg. C, using calcium phosphate (TCP) and sodium silicate as precursors. Characterization and chemical analysis of the synthesized powders were performed by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated enhanced nucleation and formation of bone like layer of HA nanocrystals at the surface of TCP nanoparticles and occurrence of HA nanocrystals during 24 h soaking of TCP in SBF solution containing silica ions. The average size of a nanoparticle, using Scherrer formula, was found to be 18.2 nm.

Numerical analysis of three-dimensional turbulent flow in a 90deg bent tube by algebraic Reynolds stress model

International Nuclear Information System (INIS)

Sugiyama, Hitoshi; Akiyama, Mitsunobu; Shinohara, Yasunori; Hitomi, Daisuke

1997-01-01

A numerical analysis has been performed for three dimensional developing turbulent flow in a 90deg bent tube with straight inlet and outlet sections by an algebraic Reynolds stress model. To our knowledge, very little has been reported about detailed comparison between calculated results and experimental data containing Reynolds stresses. In calculation, an algebraic Reynolds stress model together with a boundary-fitted coordinate system is applied to a 90deg bent tube in order to solve anisotropic turbulent flow precisely. The calculated results display comparatively good agreement with the experimental data of time averaged velocity and secondary vectors. In addition, the present method predicts as a characteristic feature that the intensity of secondary flow near the inner wall is increased immediately downstream from the bend outlet by the pressure gradient. With regard to comparison of Reynolds stresses, the present method is able to reproduce well the distributions of streamwise normal stress and shear stress defined streamwise and radial velocity fluctuation except for the shear stress defined streamwise and circumferential velocity fluctuation. The present calculation has been found to simulate many features of the developing flow in bent tube satisfactorily, but it has a tendency to underpredict the Reynolds stresses. (author)

Corrections to the one-pion exchange amplitudes for the reaction np→pΔsub(33)sup(deg)

International Nuclear Information System (INIS)

Ferraz De Camargo, A.; Laville, J.L.

1978-01-01

A simple modified one-pion exchange model is applied to the analysis of the reaction np→pΔsub(33)sup(deg) from 1.39 to 1.90GeV/c. It is shown that important corrections to the evasive amplitudes can account for the turnover observed in the differential cross-section and rather good fits are obtained. Such corrections do not agree with the prescription known as ''poor man's absorption''. The results for the density matrix elements are briefly discussed

Temperature dependence, 0 to 40 deg. C, of the mineralogy of Portland cement paste in the presence of calcium carbonate

International Nuclear Information System (INIS)

Matschei, Thomas; Glasser, Fredrik P.

2010-01-01

Thermodynamic calculations disclose that significant changes of the AFm and AFt phases and amount of Ca(OH) 2 occur between 0 and 40 deg. C; the changes are affected by added calcite. Hydrogarnet, C 3 AH 6 , is destabilised at low carbonate contents and/or low temperatures 3 -ettringite. A nomenclature scheme is proposed and AFm-AFt phase relations are presented in isothermal sections at 5, 25 and 40 deg. C. The AFt and AFm phase relations are depicted in terms of competition between OH, CO 3 and SO 4 for anion sites. Diagrams are presented showing how changing temperatures affect the volume of the solid phases with implications for space filling by the paste. Specimen calculations are related to regimes likely to occur in commercial cements and suggestions are made for testing thermal impacts on cement properties by defining four regimes. It is concluded that calculation provides a rapid and effective tool for exploring the response of cement systems to changing composition and temperature and to optimise cement performance.

The study of 90 deg. gamma ray production cross sections for interactions of 14.9 Mev neutrons with C, Al, V, Fe, Co, Nb samples

International Nuclear Information System (INIS)

Tang Lin; Yan Yiming; Zhou Hongyu; Wen Shenlin; Wang Qi; Sun Shuxu; Ding Xiaoji; Wang Wanhong

1987-04-01

The (n,xr) reactions have been studied for incident neutron energy 14.9 Mev and for the samples C, Al, V, Fe, Co and Nb. The pulsed beam Time-of-Flight technique was adopted to discriminate neutrons and de-excitation r-rays and to improve the background conditions of the experiment. 90 deg. differential gamma production cross sections as the results of experiments are presented. Due to very low background many new r-rays peaks have been obtained. (author). 14 refs, 12 figs, 1 tab

Effect of Alloying Element and Heat Treatment on Mechanical and Corrosion Property of Ni-Cr-Co-Mo Alloy at 950 .deg. C

International Nuclear Information System (INIS)

Kim, Dong Jin; Jung, Su Jin; Moon, Byung Hak; Kim, Sung Woo; Lim, Yun Soo; Kim, Hong Pyo

2013-01-01

Helium is used as a coolant in a VHTR owing to its high thermal conductivity, inertness, and low neutron absorption. However, helium inevitably includes impurities that create an imbalance in the surface reactivity at the interface of the coolant and the exposed materials. The carbon monoxide, methane, hydrogen, and water that are formed by the reaction with the graphite in the core induce various surface reactions that lead to material property changes over time. According to previous reports it was predicted that the outer oxide layer thickness, internal oxide depth, and carbidedepleted zone depth increase to 116 μm, 600 μm, and 1000 μm, respectively, when Alloy 617 is exposed to a plausible impure helium environment at 950 .deg. C for 20 years, based on the reaction rate constant determined from the short time experiment. These values are large enough to pay attention to the material degradation at high temperature, i. e., the life of the IHX. Therefore, finding the range of impurity concentration at which the material is stable, based on the thermodynamics and kinetics determined by a long-term experiment, is very important to the optimum chemistry control for a life extension. Another countermeasure is to improve the material performance through alloy development. Commercial nickel-based wrought alloy is strengthened by a solid solution and precipitation hardening mechanism in a wide temperature range of 500 to 900 .deg. C. The γ' significantly contributes to the strengthening by forming an anti-phase boundary and preventing a dislocation motion at an intermediate temperature range of 700 to 800 .deg. C, but is no longer stable above this temperature range. However, the material for an IHX needs to fulfill the mechanical property requirements in a narrow, very high temperature range of 850 to 950 .deg. C rather than in a wide temperature range. Therefore, it is worth making the effort to find an optimum combination of alloying elements and processing

Effect of Alloying Element and Heat Treatment on Mechanical and Corrosion Property of Ni-Cr-Co-Mo Alloy at 950 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Jin; Jung, Su Jin; Moon, Byung Hak; Kim, Sung Woo; Lim, Yun Soo; Kim, Hong Pyo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

Helium is used as a coolant in a VHTR owing to its high thermal conductivity, inertness, and low neutron absorption. However, helium inevitably includes impurities that create an imbalance in the surface reactivity at the interface of the coolant and the exposed materials. The carbon monoxide, methane, hydrogen, and water that are formed by the reaction with the graphite in the core induce various surface reactions that lead to material property changes over time. According to previous reports it was predicted that the outer oxide layer thickness, internal oxide depth, and carbidedepleted zone depth increase to 116 μm, 600 μm, and 1000 μm, respectively, when Alloy 617 is exposed to a plausible impure helium environment at 950 .deg. C for 20 years, based on the reaction rate constant determined from the short time experiment. These values are large enough to pay attention to the material degradation at high temperature, i. e., the life of the IHX. Therefore, finding the range of impurity concentration at which the material is stable, based on the thermodynamics and kinetics determined by a long-term experiment, is very important to the optimum chemistry control for a life extension. Another countermeasure is to improve the material performance through alloy development. Commercial nickel-based wrought alloy is strengthened by a solid solution and precipitation hardening mechanism in a wide temperature range of 500 to 900 .deg. C. The γ' significantly contributes to the strengthening by forming an anti-phase boundary and preventing a dislocation motion at an intermediate temperature range of 700 to 800 .deg. C, but is no longer stable above this temperature range. However, the material for an IHX needs to fulfill the mechanical property requirements in a narrow, very high temperature range of 850 to 950 .deg. C rather than in a wide temperature range. Therefore, it is worth making the effort to find an optimum combination of alloying elements and processing

The composition of cement hydrating at 60 deg C from synchrotron radiation

International Nuclear Information System (INIS)

Auld, J.; Turner, K.; Thorogood, G.J.; Ball, C.J.; Aldridge, L.P.; Taylor, J.C.

2002-01-01

Full text: Cement consists of 5 phases C3S, C2S, C3A, C4AF (where C denotes CaO, S denotes SiO 2 , A denotes AI 2 O 3 and F denotes Fe 2 O 3 ) and gypsum. When cement hydrates it forms an amorphous calcium silicate hydrate (C-S-H) as well as the crystalline ettringite and calcium hydroxide. The x-ray diffraction pattern of the hydrated cement is difficult to interpret because of its complexity. In addition, the overlapping lines from the remaining cement compounds make it difficult to quantify the amount of the crystalline components present. Using Rietveld analysis we have been able to interpret the patterns obtained from synchrotron x-ray diffraction patterns obtained at the Photon Factory at the Australian National Beamline Facility using BIGDIF. The changes in the composition of the hydrated cement paste were determined as a function of time during hydration at 60 deg C. Copyright (2002) Australian X-ray Analytical Association Inc

Bipolar characteristics of AlGaN/AlN/GaN/AlGaN double heterojunction structure with AlGaN as buffer layer

International Nuclear Information System (INIS)

Peng, Enchao; Wang, Xiaoliang; Xiao, Hongling; Wang, Cuimei; Yin, Haibo; Chen, Hong; Feng, Chun; Jiang, Lijuan; Hou, Xun; Wang, Zhanguo

2013-01-01

Highlights: •2DEG and 2DHG coexist in the AlGaN/AlN/GaN/AlGaN DH-structure. •The sheet densities of 2DEG and 2DHG vary with buffer Al content and GaN thickness. •The conditions for the disappearance of 2DHG are discussed. •Increasing buffer Al content provides better electron confinement. •Dislocation scattering is reduced in the DH-structure. -- Abstract: This is a theoretical study of AlGaN/AlN/GaN/AlGaN double heterojunction (DH) structure with AlGaN as buffer layer. Our calculation shows that as the buffer Al content increases, though two-dimensional electron gas (2DEG) sheet density decreases, the channel back-barrier caused by polarization-induced electric field in GaN provides better electron confinement. And under certain conditions the DH-structure shows bipolar characteristics, with an additional two-dimensional hole gas (2DHG) formed at GaN/AlGaN interface. The influence of the buffer Al content and GaN channel thickness on the 2DEG and 2DHG sheet densities are investigated, and the conditions for the disappearance of 2DHG are discussed. Also, the mobility inhibited by dislocation scattering is enhanced in DH-structure due to the enhancement of screening effect of the 2DEG

Low Cycle Fatigue Behavior of Alloy 617 Base Metal and Welded Joints at Room Temperature and 850 .deg. C for VHTR Applications

Energy Technology Data Exchange (ETDEWEB)

Kim, Seon Jin; Dew, Rando T. [Pukyong National Univ., Busan (Korea, Republic of); Kim, Woo Gon; Kim, Min Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

Low cycle fatigue (LCF) is an important design consideration for high temperature IHX components. Moreover, some of the components are joined by welding techniques and therefore the welded joints are unavoidable in the construction of mechanical structures. Since Alloy 617 was introduced in early 1970s, many attempts have been made in the past two decades to evaluate the LCF and creep-fatigue behavior in Alloy 617 base metal at room temperature and high temperature. However, little research has focused on the evaluation and characterization of the Alloy 617 welded joints. butt-welded joint specimens was performed at room temperature and 850 .deg. C. Fatigue lives of GTAW welded joint specimens were lower than those of base metal specimens. LCF cracking and failure in welded specimens initiated in the weld metal zone and followed transgranluar dendritic paths for both at RT and 850 .deg. C.

Bulk Shielding Calculation for 90 .deg. Bending Section of RISP

Energy Technology Data Exchange (ETDEWEB)

Oh, J. H.; Jung, N. S.; Lee, H. S. [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Oranj, L. Mokhtari [POSTECH, Pohang (Korea, Republic of); Ko, S. K. [Univ. of Ulsan, Ulsan (Korea, Republic of)

2014-10-15

The charge state of {sup 238}U beams with maximum intensity was 79+ among multi-charge states of 70+ to 89+, which were estimated by using LISE++ code. The bending section consists of twenty four quadrupoles, two dipoles, two two-cell type superconducting RF cavities and eleven slits. The complicated radiation environment is caused by the beam losses occurred normally during the stripping process and when the produced {sup 238}U beams are transported along the beam line. Secondary radiations generated by {sup 238}U beams irradiation are very important for predicting the prompt and residual doses and the radiation damage at the component. The production characteristics of neutron and photon from thin carbon and thick iron were studied to set up the shielding strategy. The dose estimation was done to the pre-designed the tunnel structure. In these calculations, major Monte Carlo codes, PHITS and FLUKA, were used. The present study provided information of shielding analysis for the 90 .deg. bending section of RISP facility. The source term was evaluated to determine fundamental parameter of the shielding analysis using PHITS and FLUKA codes. And the distribution of the dose rate at the outside of thick shielding wall was presented.

Misura de Massa e Larghezza degli Stati $x_1$ e $x_2$ del Charmonio Formati in Interazioni $p - \\bar{p}$

Energy Technology Data Exchange (ETDEWEB)

Pallavicini, Marco [Univ. of Genoa (Italy)

1995-01-01

Oggetto di questa tesi è la misura di alcune caratteristiche fisiche ( massa, larghezza, e larghezza parziale in p - p) degli stati 3 Pi e 3 A del charmonio, - overo del sistema legato di un quark "charm" e del suo antiquark-, nell'ambito dell'esperimento E-760, installato nell'accumulatore di antiprotoni del Fermilab (U.S.A).

76 FR 38077 - Special Local Regulations and Safety Zones; Recurring Events in Captain of the Port New York Zone

Science.gov (United States)

2011-06-29

...: All Zone. waters of Long Island Sound in an area bound by the following points: 40[deg]51'43.5'' N 073... Zone. located in approximate position 40[deg]51'52'' N 073[deg]56'24'' W (NAD 1983), approximately 1750...] RIN 1625-AA00; 1625-AA08 Special Local Regulations and Safety Zones; Recurring Events in Captain of...

Geochronology and Composition of the 2005-06 Volcanic Eruptions of the East Pacific Rise, 9deg 46'-56'N

Science.gov (United States)

Rubin, K. H.; Perfit, M. R.; Fornari, D. J.; Soule, S. A.; Tolstoy, M.; Waldhauser, F.

2006-12-01

Following the discovery of a likely eruption during an ocean bottom seismometer (OBS) recovery cruise (4/06, R/V Knorr), two rapid response cruises (5/06, R/V New Horizon and 6/06 R/V Atlantis) confirmed the new eruptions and observed and sampled newly emplaced sea floor to understand eruption conditions and impacts on hydrothermalism and ecology at the East Pacific Rise (EPR) Ridge2000 ISS near 9° 50'N. We report results of an ongoing effort to obtain high resolution 210Po-210Pb radiometric dates and compositions of young lava sampled on those expeditions, to understand when the eruptive activity occurred, its variation in space and time, and the nature of the magma reservoir(s) involved. The 210Po-210Pb method can produce monthly resolution ages from time series measurements of 210Po activity in volcanic glass after initially being degassed during eruption (Rubin et al., Nature, 1994). All analyses are being conducted on samples distributed throughout the flow field, which extends at least 18 km along the ridge axis from 9° 46'N to 9° 56'N, and includes a significant area of lava extrusion from an off-axis fissure ridge located ~~600m east of the ridge axis in the northern portion of the study area. Final 210Po ages must await the completion of multiple repeat analyses on each sample over ca 1 year, but important age constraints can be estimated by comparing measured (210Po/238U) activity ratio in the lavas with the known (limited) range in (210Pb/238U) in other young, but pre-2005 lava in the area. 210Po ranges by more than a factor of two among 10 samples undergoing analysis, which is greater than can be explained by small chemical variations between the lavas. This implies either that the samples are vastly different in U-series nuclide composition or differ in age by up to two 210Po half-lives (T1/2 = 138.4 days ~4 mos.). Preliminary microprobe, ICP-MS and TIMS-ID analyses indicate that the new lavas are slightly more differentiated than 1991

Effect of surface roughness scattering on the transport properties of a 2DEG

International Nuclear Information System (INIS)

Yarar, Z.

2004-01-01

In this work surface roughness scattering of electrons in a two dimensional electron gas (2DEG) formed at heterojunction interfaces is investigated for various auto-correlation functions. Gaussian, exponential and Lorentzian auto-correlation functions are used to represent surface roughness. Poisson and Schrodinger equations are solved self consistently at the hetero interface to find the energy levels, the wave functions corresponding to each level and electron concentrations at each level. Using these wave functions and the auto-correlation functions mentioned above, the scattering rates due to surface roughness are calculated. Scattering rates resulting from acoustic and optical phonons are also calculated. These rates are used to study the transport properties of the two dimensional electrons using ensemble Monte Carlo method at various temperatures. Emphasis is given to the effect of surface roughness scattering on the transport properties of the electrons

The effect of vacuum environment on creep rupture properties of Inconel 617 at 1000 deg C

International Nuclear Information System (INIS)

Ohnami, Masateru; Imamura, Riuzo

1981-01-01

The creep rupture strength of nickel-base superalloy in weakly acidic gas at high temperature above 1000 deg C lowers remarkably as compared with that in the atmosphere, and this problem is one of the important subjects in connection with the research and development of high temperature heat exchangers for multi-purpose high temperature gas-cooled reactor system being developed in Japan. In the case of Inconel 617, abnormal decarbonization phenomenon occurs in weakly acidic gas, and this is regarded as the cause of lowering the creep strength. In this study, the effects of the decarbonization in weak vacuum at 1000 deg C and the oxidation of Inconel 617 on its crack occurrence and propagation were clarified experimentally with notched plate test pieces. The material used was Inconel 617 nickel-base superalloy made by Huntington Alloys Inc. in the U.S. The creep rupture experiment was carried out with a simple tension creep tester. At the nominal stress of 3.5 kg/mm 2 , the creep rupture time in 0.3 Torr was the shortest when the grain size was 78 μm, and the creep rupture time increased as the grain size became larger. The creep rupture time in 0.3 Torr decreased to a half of that in the atmosphere. In 0.3 Torr, cracks occurred early, and propagated fast as compared with in the atmosphere. This is because the local creep velocity at the bottom of notches and in front of creep cracks is fast owing to the lack of protective oxide film. (Kako, I.)

TOMS/Earth Probe UV-B Erythemal Local Noon Irradiance Monthly L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Earth Probe UV-B Erythemal Local Noon Irradiance Monthly L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. (The...

Dielectric and barrier thickness fluctuation scattering in Al2O3/AlGaN/GaN double heterojunction high-electron mobility transistors

International Nuclear Information System (INIS)

Ji, Dong; Lu, Yanwu; Liu, Bing; Liu, Guipeng; Zhu, Qinsheng; Wang, Zhanguo

2013-01-01

The two-dimensional electron gas (2DEG) mobility limited by dielectric and barrier thickness fluctuations (TF) scattering in Al 2 O 3 /AlGaN/GaN double heterojunction high-electron mobility transistors (HEMTs) is calculated. Calculation shows that thickness fluctuation scattering is the main limitation in Al 2 O 3 /AlGaN/GaN double heterojunction HEMTs with thin Al 2 O 3 layer thicknesses. In addition, a study of 2DEG mobility as a function of 2DEG density, n s , shows that TF scattering acts as the main limitation when n s exceeds 2 × 10 12 cm −2 . The results may be used to design HEMTs to obtain higher 2DEG mobilities by modulating the dielectric layer and barrier thicknesses or 2DEG density. - Highlights: • The mobility limited by thickness fluctuation (TF) scattering is studied. • Results show that thickness fluctuation scattering is the main limitation. • Two-dimensional electron gas (2DEG) mobility is a function of 2DEG density. • TF scattering is the main limitation when 2DEG density exceeds 2 × 10 12 cm −2

Investigation of AlGaN/GaN high electron mobility transistor structures on 200-mm silicon (111) substrates employing different buffer layer configurations.

Science.gov (United States)

Lee, H-P; Perozek, J; Rosario, L D; Bayram, C

2016-11-21

AlGaN/GaN high electron mobility transistor (HEMT) structures are grown on 200-mm diameter Si(111) substrates by using three different buffer layer configurations: (a) Thick-GaN/3 × {Al x Ga 1-x N}/AlN, (b) Thin-GaN/3 × {Al x Ga 1-x N}/AlN, and (c) Thin-GaN/AlN, so as to have crack-free and low-bow (GaN HEMT structures. The effects of buffer layer stacks (i.e. thickness and content) on defectivity, stress, and two-dimensional electron gas (2DEG) mobility and 2DEG concentration are reported. It is shown that 2DEG characteristics are heavily affected by the employed buffer layers between AlGaN/GaN HEMT structures and Si(111) substrates. Particularly, we report that in-plane stress in the GaN layer affects the 2DEG mobility and 2DEG carrier concentration significantly. Buffer layer engineering is shown to be essential for achieving high 2DEG mobility (>1800 cm 2 /V∙s) and 2DEG carrier concentration (>1.0 × 10 13  cm -2 ) on Si(111) substrates.

The gadolinium nitrate-carbamide-water and the ytterbium nitrate-carbamide-water systems at 30 deg C

International Nuclear Information System (INIS)

Khudajbergenova, N.; Sulajmankulov, K.

1980-01-01

Gadolinium nitrate-carbamide-water(1) and ytterbium nitrate-carbamide-water(2) systems are studied at 30 deg C by the solubility method. Two new compounds are formed in the system(1). One of them is incongruent Gd(NO 3 ) 3 x3CON 2 H 4 and Gd(NO 3 ) 3 x4CON 2 H 4 is congruently soluble. Incongruent compound of Yb(NO 3 ) 3 xCON 2 H 4 composition and congruently soluble Yb(NO 3 ) 3 x4CON 2 H 4 are also formed in the system(2). Presented are solubility isotherms of the systems [ru

The study of the distribution of Ca{sup 45} with time in the newborn rat by the autoradiography method at - 195 deg; Etude de la distribution du {sup 45}Ca en fonction du temps chez le rat nouveau-ne par la methode d'autoradiographie a -195 deg

Energy Technology Data Exchange (ETDEWEB)

Kellershohn, C; Pellerin, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1961-07-01

Ca{sup 45} metabolism has been studied as a function of time by autoradiography at -195 deg. C in the new-born rat after sub-epidermal dorsal injected of 20 micro-curies per animal. This study confirms: 1) The existence of a rapidly exchangeable calcium bone fraction; 2) A considerable intestinal excretion of radio-calcium, much greater than the urinary elimination; 3) A gradual transfer of the activity for the long bones of the epiphyseal to the diaphyseal regions during growth, together with secondary modifications during ossification. (author) [French] Le metabolisme du {sup 45}Ca est etudie en fonction du temps par autoradiographie a -195 deg. C, chez le rat nouveau-ne apres injection sous-epidermique dorsale de 20 microcuries par animal. Cette etude confirme: 1) l'existence d'une fraction calcique osseuse rapidement echangeable; 2) une excretion intestinale considerable du radiocalcium, tres superieure a l'elimination urinaire; 3) un transfert progressif de l'activite pour les os longs des regions epiphysaires aux regions diaphysaires au cours de la croissance, ainsi que les remaniements secondaires au cours de l'ossification. (auteur)

Two-dimensional electron gas in AlGaN/GaN heterostructures

International Nuclear Information System (INIS)

Li, J.Z.; Lin, J.Y.; Jiang, H.X.; Khan, M.A.; Chen, Q.

1997-01-01

The formation of a two-dimensional electron gas (2DEG) system by an AlGaN/GaN heterostructure has been further confirmed by measuring its electrical properties. The effect of persistent photoconductivity (PPC) has been observed and its unique features have been utilized to study the properties of 2DEG formed by the AlGaN/GaN heterointerface. Sharp electronic transitions from the first to the second subbands in the 2DEG channel have been observed by monitoring the 2DEG carrier mobility as a function of carrier concentration through the use of PPC. These results are expected to have significant implications on field-effect transistor and high electron mobility transistor applications based on the GaN system. copyright 1997 American Vacuum Society

L’esperienza poetica nell’Argentina degli anni Sessanta

Directory of Open Access Journals (Sweden)

S. Lafuente

2012-08-01

Full Text Available ENJuan Gelman, Leónidas Lamborghini, Francisco Urondo, César Ferández Moreno, among the most famous of the poetic generation in Argentina during the Sixties, take up the concept of critical verbal art that the Hispanic-American vanguard had proposed as a priority. They finished the work of their predecessors, especially that of the late Huidobro, who, after Altazor left the more external aspects of the play behind, and of César Vallejo, creating a poetic area where emotion and subjectivity coexist with linguistic experimentation, where the pleasure of construction and the subtleties of linguistic deformations are inexorably tied to sentiment.In obliterating the distance between I and You, their poetry abandons the passage between different textual practices and gives space to an inter-subjectivity that leads the reader to forget his passivity and become active in sensory production.Keywords: avant-garde, Argentine poetry, the Sixties, linguistic experimentationITJuan Gelman, Leónidas Lamborghini, Francisco Urondo, César Ferández Moreno, fra i nomi più noti della generazione poetica argentina degli anni Sessanta, riprendono la concezione di un’arte verbale critica che l’avanguardia ispanoamericana aveva proposto come prioritaria. Completano il lavoro dei suoi predecessori, soprattutto dell’ultimo Huidobro, che dopo Altazor abbandona gli aspetti più esterni del gioco, e di César Vallejo, creando uno spazio poetico dove l’emozione, la soggettività, coesistono con la sperimentazione del linguaggio, dove il piacere della costruzione, delle sottigliezze delle deformazioni linguistiche sono indissolubilmente legate al sentimento.La loro poesia, nell’abolire la distanza fra Io e Tu, lascia aperto il passaggio fra le pratiche testuali differenti e dà spazio a un’intersoggettività che induce il lettore ad abbandonare la sua passività e a diventare attivo nella produzione del senso.Parole chiave: avanguardia, poesia argentina

TOMS/Nimbus-7 UV-B Erythemal Local Noon Irradiance Daily L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Nimbus-7 UV-B Erythemal Local Noon Irradiance Daily L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. The Total Ozone...

Systems of amonium polyborates - monoammonium phosphate -water at 25 deg C. Sistemy poliboraty ammoniya - monoammonijfosfat - voda pri 25 grad S

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Sadetdinov, Sh V; Polenov, A D; Mikhajlov, V I [Chuvashskij Gosudarstvennyj Pedagogicheskij Inst., Cheboksary (Russian Federation)

1992-11-01

It is established by solubility and refractometry methods at 25 deg C that systems of ammonium tetraborate (pentaborate) monoammonium phosphate-water refer to sumple eutonic type. The ammonium borates and monoammoniumphosphate exert salting effect over each other. It is found that phosphate borate compositions on the basis of ammonium salts are characterized by lower inhibitor properties as compared to sodium salts.

Temperature dependent microwave performance of AlGaN/GaN high-electron-mobility transistors on high-resistivity silicon substrate

International Nuclear Information System (INIS)

Arulkumaran, S.; Liu, Z.H.; Ng, G.I.; Cheong, W.C.; Zeng, R.; Bu, J.; Wang, H.; Radhakrishnan, K.; Tan, C.L.

2007-01-01

The influence of temperature (- 50 deg. C to + 200 deg. C) was studied on the DC and microwave characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) on high resistivity Si substrate for the first time. The AlGaN/GaN HEMTs exhibited a current-gain cut-off frequency (f T ) of 11.8 GHz and maximum frequency of oscillation (f max ) of 27.5 GHz. When compared to room temperature values, about 4% and 10% increase in f T and f max and 23% and 39.5% decrease in f T and f max were observed when measured at - 50 deg. C and 200 deg. C, respectively. The improvement of I D , g m f T , and f max at - 50 deg. C is due to the enhancement of 2DEG mobility and effective electron velocity. The anomalous drain current reduction in the I-V curves were observed at low voltage region at the temperature ≤ 10 deg. C but disappeared when the temperature reached ≥ 25 deg. C. A positive threshold voltage (V th ) shift was observed from - 50 deg. C to 200 deg. C. The positive shift of V th is due to the occurrence of trapping effects in the devices. The drain leakage current decreases with activation energies of 0.028 eV and 0.068 eV. This decrease of leakage current with the increase of temperature is due to the shallow acceptor initiated impact ionization

Effect of various lanthanum sol-gel coatings on the 330Cb (Fe-35Ni-18Cr-1Nb-2Si) oxidation at 900 deg. C

Energy Technology Data Exchange (ETDEWEB)

Buscail, H., E-mail: buscail@iut.u-clermont1.fr [Clermont Universite- LVEEM, 8 rue J.B. Fabre, BP 219, 43006 Le Puy en Velay (France); Issartel, C.; Riffard, F.; Rolland, R.; Perrier, S. [Clermont Universite- LVEEM, 8 rue J.B. Fabre, BP 219, 43006 Le Puy en Velay (France); Fleurentin, A. [CETIM, 52 av Felix Louat, BP 80067, 60304 Senlis (France); Josse, C. [L' ICB UMR5209 CNRS, BP 47870, 21078 Dijon (France)

2011-11-01

The influence of a lanthanum sol-gel coating on the oxide scale adherence has been studied during the 330Cb (Fe-35Ni-18Cr-1Nb-2Si) oxidation at 900 deg. C, in air. The alloy oxidation is performed in order to generate a protective chromia scale acting as a good barrier against carburization. Argon annealing of lanthanum sol-gel coatings have been performed at various temperatures in order to find the best conditions to insure the scale adherence. Kinetic results show that lanthanum sol-gel coatings lead to a lower oxidation rate compared to blank specimens. Thermal cycling tests on lanthanum the sol-gel coated specimen show that the oxide scale formed at 900 deg. C, in air, is adherent.

OMI/Aura Near UV Aerosol Optical Depth and Single Scattering Albedo Daily L3 Global 1x1 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI-Aura level-3 daily global gridded (1x1 deg) near-UV Aerosol data product OMAERUVd based on the enhanced algorithm is available from the NASA Goddard Earth...

Retrospective dosimetry assessment using the 380 deg. C thermoluminescence peak of tooth enamel

Energy Technology Data Exchange (ETDEWEB)

Secu, C.E. [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, M. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Secu, M., E-mail: msecu@infim.ro [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, C.; Paraschiva, V. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Barca, C. [Faculty of Physics, University of Bucharest, 77125 Bucharest-Magurele (Romania)

2011-10-15

The thermoluminescence (TL) response to gamma-ray irradiation of tooth enamel is reported. The tooth enamel was separated from dentine by using mechanical and physico-chemical procedures followed by grinding (grain size {approx}100 {mu}m) and etching. The TL was attributed to the recombination of CO{sub 2}{sup -} radicals incorporated into or attached to the surface of hydroxyapatite crystals. The growth of the {approx}380 deg. C TL peak with absorbed dose was examined with irradiated tooth enamel samples and reconstructed doses evaluated for tooth enamel samples from four human subjects. - Highlights: > Thermoluminescence response after gamma-ray irradiation of tooth enamel was investigated. > Thermoluminescence was attributed to the recombination of CO{sub 2}{sup -} radicals. > CO{sub 2}{sup -} radicals are produced inside or at the surface of hydroxyapatite crystals. > From the growth of the 380C peak reconstructed doses have been evaluated.

MeB5O8(Me-Li, Na, K, NH4)-H2NCONHCOCH3-H2O system at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Fedorov, Yu.A.; Molodkin, A.K.; Tsekhanskij, R.S.

1986-01-01

Using the methods of isothermal solubility, densi- and refractometry, systems MB 5 O 8 (M-Li, Na, K, NH 4 )-acetylcarbamide - H 2 O at 25 deg C have been studied. It is ascertained, that the systems investigated are of simple eutonic type

Results of a M = 5.3 heat transfer test of the integrated vehicle using phase-change paint techniques on the 0.0175-scale model 56-OTS in the NASA/Ames Research Center 3.5-foot hypersonic wind tunnel

Science.gov (United States)

Marroquin, J.

1985-01-01

An experimental investigation was performed in the NASA/Ames Research Center 3.5-foot Hypersonic Wind Tunnel to obtain supersonic heat-distribution data in areas between the orbiter and external tank using phase-change paint techniques. The tests used Novamide SSV Model 56-OTS in the first and second-stage ascent configurations. Data were obtained at a nominal Mach number of 5.3 and a Reynolds number per foot of 5 x 10 to the 6th power with angles of attack of 0 deg, +/- 5 deg, and sideslip angles of 0 deg and +/- 5 deg.

Diffraction of 4He atoms from the (001) face of LiF at 10 deg K

International Nuclear Information System (INIS)

Boato, G.; Cantini, P.; Cardillo, M.J.; Tatarek, R.

1974-01-01

A new atom-surface scattering apparatus, which takes advantage of the use of low temperatures, is described. The apparatus allows differential cross section measurements to be carried out with good angular resolution and sensitivity, holding the surface around liquid helium temperatures. The diffractive scattering of a supersonic helium beam from a (001) cleaved LiF surface at 10 deg K was studied. The normalized integrated intensities of all diffracted peaks for normal incidence are given and compared with a quantum surface rainbow theory developed by LEVI et al. The observation of bound state resonances in the peak intensity plotted as a function of incident angle is discussed

On solubility of perchloric (periodic) acid and α-cyanacetanmide in aqueous solutions at 25 deg C

International Nuclear Information System (INIS)

Omarova, R.A.; Balysbekov, S.M.; Erkasov, R.Sh.; Nikolenko, O.N.

1996-01-01

Acid-base interaction within perchloric (periodic) acid-α-cyanacetamide-water systems in studied by method of solubility under isothermal conditions at 25 deg C. Solubility regularities of crystalline α-cyanacetamide in perchloric and periodic acid solutions are determined, the concentration limits of formation of a new solid phase-tris(α-cyanacetamide) perchlorate within perchloric acid-α-cyanacetamide-water system are determined. The compound is identified by means of chemical and X-ray phase analyses, its density and melting temperature are determined. Iodic acid and α-cyanacetamide water solution base system is shown to belong to a simple eutonic type. 2 refs., 3 figs., 2 tabs

Study of solubility in Ca(NO3)2-Ln(NO3)3-H2O systems at 25 deg C (Ln-Ce,Pr,Nd)

International Nuclear Information System (INIS)

Shevchuk, V.G.; Dryuchko, A.G.; Bunyakina, N.V.; Storozhenko, D.A.

1983-01-01

The isothermal method has been used to study solubility in the systems calcium nitrate-cerium (praseodymium, neodymium) nitrate water at 25 deg C. The systems are attributed to eutonic type. Formations of complex compounds and solid solutions are not disclosed

The 500 deg. C isothermal section of the Gd-Tb-Co ternary system

International Nuclear Information System (INIS)

Zhou, K.W.; Zhuang, Y.H.; Li, J.Q.; Zhu, Q.M.; Deng, J.Q.

2006-01-01

The isothermal section of the phase diagram of the Gd-Tb-Co ternary system at 500 deg. C was investigated by X-ray powder diffraction, differential thermal analysis and metallographic analysis techniques. In this isothermal section, there are nine single-phase regions, eight two-phase regions and none three-phase region. No ternary compound was found. The compounds Gd 2 Co 17 and Tb 2 Co 17 , Gd 2 Co 7 and Tb 2 Co 7 , GdCo 3 and TbCo 3 , GdCo 2 and TbCo 2 , Gd 4 Co 3 and Tb 4 Co 3 , Gd 12 Co 7 and Tb 12 Co 7 , Gd 3 Co and Tb 3 Co, Gd and Tb form a continuous series of solid solutions. In addition, we experimentally determined the vertical section of pseudobinary system and the Curie temperature of Gd 1-x Tb x Co 2 (x from 0 to 1) series alloys

Sensitive detection of proteasomal activation using the Deg-On mammalian synthetic gene circuit.

Science.gov (United States)

Zhao, Wenting; Bonem, Matthew; McWhite, Claire; Silberg, Jonathan J; Segatori, Laura

2014-04-08

The ubiquitin proteasome system (UPS) has emerged as a drug target for diverse diseases characterized by altered proteostasis, but pharmacological agents that enhance UPS activity have been challenging to establish. Here we report the Deg-On system, a genetic inverter that translates proteasomal degradation of the transcriptional regulator TetR into a fluorescent signal, thereby linking UPS activity to an easily detectable output, which can be tuned using tetracycline. We demonstrate that this circuit responds to modulation of UPS activity in cell culture arising from the inhibitor MG-132 and activator PA28γ. Guided by predictive modelling, we enhanced the circuit's signal sensitivity and dynamic range by introducing a feedback loop that enables self-amplification of TetR. By linking UPS activity to a simple and tunable fluorescence output, these genetic inverters will enable a variety of applications, including screening for UPS activating molecules and selecting for mammalian cells with different levels of proteasome activity.

Tidal and solar cycle effects on the OI 5577 A, NaD and OH(8,3) airglow emissions observed at 23 deg S

International Nuclear Information System (INIS)

Takahashi, H.; Sahai, Y.; Batista, P.P.

1984-01-01

The upper mesosphere airglow emissions OI 5577, NaD and OH have been observed at Cachoeira Paulista (22.7 deg S; 45.0 deg W) Brazil. Nocturnal variations and their seasonal dependencies in amplitude and phase, and the annual variations of these emissions are presented, analysing the data obtained from 1977 to 1982 during the ascending phase of the last solar cycle. The nocturnal variations of the OI 5577 emission and the OH rotational temperature showed a significant semidiurnal oscillation, with the phase of maximum moving from midnight in January to early morning in June. Semiannual variation of the OI 5577 and NaD emissions with the maximum intensities in April/May and October/November were observed. The OH rotational temperature, however, showed an annual variation, maximum in summer and minimum in winter, while no significant seasonal variation was found in the OH emission intensities. Long-term intensity variations are also presented with the solar sunspot numbers and the 10.7 cm flux. (author)

Low cycle fatigue behaviors of low alloy steels in 310 .deg. C deoxygenated water

International Nuclear Information System (INIS)

Jang, Hun

2008-02-01

After low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310 .deg. C deoxygenated water, the fatigue surface and the sectioned area of specimens were observed to understand the effect of the cyclic strain rate on the environmentally assisted cracking behaviors. From the fatigue crack morphologies of the specimen tested at a strain rate of 0.008 %/s, unclear ductile striations and blunt crack tip were observed. So, metal dissolution could be the main cracking mechanism of the material at the strain rate. On the other hand, on the fatigue surface of the specimen tested at strain rates of 0.04 and 0.4 %/s, the brittle cracks and the flat facets, which are the evidence of the hydrogen induced cracking, were observed. Also, the tendency of linkage between the main crack and micro-cracks was observed on the sectioned area. Therefore, the main cracking mechanism at the strain rates of 0.04 and 0.4 %/s could be the hydrogen induced cracking. Additionally, the evidence of the dissolved MnS inclusions was observed on the fatigue surface from energy dispersive x-ray spectrometer analyses. So, despite of the low sulfur content of the test material, the sulfides seem to contribute to environmentally assisted cracking of SA508 Gr.1a low alloy steel in 310 .deg. C deoxygenated water. Additionally, our experimental fatigue life data of SA508 Gr.1a low alloy steel (heat A) showed a consistent difference with statistical model produced in argon national laboratory. So, additional low cycle fatigue tests of other heat SA508 Gr.1a (heat B) and SA508 Gr.3 low alloy steels were performed to investigate the effect of material variability on fatigue behaviors of low alloy steels in 310 .deg. C deoxygenated water. In results, the fatigue lives of three low alloy steels were increased following order: SA508 Gr.1a low alloy steel - heat A, SA508 Gr.3 low alloy steel, and SA508 Gr.1a low alloy steel - heat B. From microstructure observation, the fatigue surface of SA508 Gr.1a low alloy

Effect of chloride concentration on the solubility of amorphous uranium dioxide at 25deg C under reducing conditions

International Nuclear Information System (INIS)

Aguilar, M.; Casas, I.; Pablo, J. de; Torrero, M.E.

1991-01-01

The dependence of the solubility of a microcrystalline uranium dioxide on the chloride concentration has been studied at 25deg C under reducing conditions. The concentration of uranium in solution has been found to be some orders of magnitude lower than in perchlorate media. Possible changes of both the morphology and the composition of the solid phase have been investigated by means of Energy Dispersive X-ray Analysis (EDX) and X-ray Powder Difraction (XPD). The formation of a secondary solid phase as a reason for the decrease of the solubility has been postulated. (orig.)

Pressure vessel design codes: A review of their applicability to HTGR components at temperatures above 800 deg C

International Nuclear Information System (INIS)

Hughes, P.T.; Over, H.H.; Bieniussa, K.

1984-01-01

The governments of USA and Federal Republic of Germany have approved of cooperation between the two countries in an endeavour to establish structural design code for gas reactor components intended to operate at temperatures exceeding 800 deg C. The basis of existing codes and their applicability to gas reactor component design are reviewed in this paper. This review has raised a number of important questions as to the direct applicability of the present codes. The status of US and FRG cooperative efforts to obtain answers to these questions are presented

Effect of GaN buffer polarization on electron distribution of AlGaN/GaN heterostructure

International Nuclear Information System (INIS)

He, Xiaoguang; Zhao, Degang; Liu, Wei; Yang, Jing; Li, Xiaojing; Li, Xiang

2016-01-01

The formation of 2DEG in AlGaN/GaN heterostructure is discussed in detail. A misunderstanding about the 2DEG sheet density expression is clarified. It is predicted by theoretical analysis and validated by self-consistent Schrodinger–Poisson numerical simulation that under the force of GaN polarization, large amounts of electrons will accumulate at the GaN/substrate interface in AlGaN/GaN/substrate HEMT structure. - Highlights: • The formation of 2DEG in AlGaN/GaN heterostructure is discussed in detail. • Self-consistent Schrodinger–Poisson numerical simulation is used to modulate the AlGaN/GaN/substrate structure. • It is predicted by that large amounts of electrons will accumulate at the GaN/substrate interface.

Effect of GaN buffer polarization on electron distribution of AlGaN/GaN heterostructure

Energy Technology Data Exchange (ETDEWEB)

He, Xiaoguang; Zhao, Degang, E-mail: dgzhao@red.semi.ac.cn; Liu, Wei; Yang, Jing; Li, Xiaojing; Li, Xiang

2016-06-15

The formation of 2DEG in AlGaN/GaN heterostructure is discussed in detail. A misunderstanding about the 2DEG sheet density expression is clarified. It is predicted by theoretical analysis and validated by self-consistent Schrodinger–Poisson numerical simulation that under the force of GaN polarization, large amounts of electrons will accumulate at the GaN/substrate interface in AlGaN/GaN/substrate HEMT structure. - Highlights: • The formation of 2DEG in AlGaN/GaN heterostructure is discussed in detail. • Self-consistent Schrodinger–Poisson numerical simulation is used to modulate the AlGaN/GaN/substrate structure. • It is predicted by that large amounts of electrons will accumulate at the GaN/substrate interface.

Comparison of radiosensitization by 41 deg. C hyperthermia during low dose rate irradiation and during pulsed simulated low dose rate irradiation in human glioma cells

International Nuclear Information System (INIS)

Raaphorst, G. Peter; Ng, Cheng E.; Shahine, Bilal

1999-01-01

Purpose: Long duration mild hyperthermia has been shown to be an effective radiosensitizer when given concurrently with low dose rate irradiation. Pulsed simulated low dose rate (PSLDR) is now being used clinically, and we have set out to determine whether concurrent mild hyperthermia can be an effective radiosensitizer for the PSLDR protocol. Materials and Methods: Human glioma cells (U-87MG) were grown to plateau phase and treated in plateau phase in order to minimize cell cycle redistribution during protracted treatments. Low dose rate (LDR) irradiation and 41 deg. C hyperthermia were delivered by having a radium irradiator inside a temperature-controlled incubator. PSLDR was given using a 150 kVp X-ray unit and maintaining the cells at 41 deg. C between irradiations. The duration of irradiation and concurrent heating depended on total dose and extended up to 48 h. Results: When 41 deg. C hyperthermia was given currently with LDR or PSLDR, the thermal enhancement ratios (TER) were about the same if the average dose rate for PSLDR was the same as for LDR. At higher average dose rates for PSLDR the TERs became less. Conclusions: Our data show that concurrent mild hyperthermia can be an effective sensitizer for PSLDR. This sensitization can be as effective as for LDR if the same average dose rate is used and the TER increases with decreasing dose rate. Thus mild hyperthermia combined with PSLDR may be an effective clinical protocol

Effects of film polarities on InN growth by molecular-beam epitaxy

International Nuclear Information System (INIS)

Xu, K.; Yoshikawa, A.

2003-01-01

Effects of the film polarity on InN growth were investigated in molecular-beam epitaxy (MBE). It was found that N-polarity InN could be grown at higher temperatures than In-polarity one. For the In-polarity films, which were grown on Ga-polar GaN template, the highest growth temperature was limited below 500 deg. C, and the surface morphology and crystal quality tended to be poor mainly because of the tolerated low growth temperature. While for the N-polarity InN films, which were grown on MBE-grown N-polar GaN, the growth temperature could be as high as 600 deg. C. The step-flow-like growth morphology was achieved for the InN films grown with N polarity at 580 deg. C. The resulting full widths of half maximum of x-ray rocking curve around InN (002) and (102) reflections were about 200-250 and 950-1100 arc sec, respectively. The photoluminescence of the InN films peaked at 0.697 eV. The recording Hall mobility of InN film grown in N polarity is 1400 cm 2 /V s with a background carrier concentration of 1.56x10 18 cm -3 at room temperature. For both-polarity films, we found N-rich condition was necessary for the stable InN growth

Morphological characteristic of the conventional and melt-spun Al-10Ni-5.6Cu (in wt.%) alloy

Energy Technology Data Exchange (ETDEWEB)

Karakoese, Ercan [Erciyes University, Institute of Science and Technology, Department of Physics, 38039 Kayseri (Turkey); Keskin, Mustafa, E-mail: keskin@erciyes.edu.tr [Erciyes University, Faculty of Arts and Sciences, Department of Physics, 38039 Kayseri (Turkey)

2009-12-15

The Al-10Ni-5.6Cu alloy was prepared by conventional casting and further processed melt-spinning technique. The resulting conventional cast and melt-spun ribbons were characterized using X-ray diffraction, optical microscopy, scanning electron microscopy together with energy dispersive spectroscopy, differential scanning calorimetry and microhardness techniques. The X-ray diffraction analysis indicated that ingot samples were {alpha}-Al, intermetallic Al{sub 3}Ni and Al{sub 2}Cu phases. The optical microscopy and scanning electron microscopy results show that the microstructures of rapidly solidified ribbons are clearly different from their ingot alloy. Al-10Ni-5.6Cu ribbons reveal a very fine cellular structure with intermetallic Al{sub 3}Ni particles. Moreover, at high solidification rates the melt-spun ribbons have a polygonal structure dispersed in a supersaturated aluminum matrix. The differential scanning calorimetry measurements revealed that exothermic reaction was between 290 deg. C and 440 deg. C which are more pronounced in the ternary Al-10Ni-5.6Cu alloy.

Morphological characteristic of the conventional and melt-spun Al-10Ni-5.6Cu (in wt.%) alloy

International Nuclear Information System (INIS)

Karakoese, Ercan; Keskin, Mustafa

2009-01-01

The Al-10Ni-5.6Cu alloy was prepared by conventional casting and further processed melt-spinning technique. The resulting conventional cast and melt-spun ribbons were characterized using X-ray diffraction, optical microscopy, scanning electron microscopy together with energy dispersive spectroscopy, differential scanning calorimetry and microhardness techniques. The X-ray diffraction analysis indicated that ingot samples were α-Al, intermetallic Al 3 Ni and Al 2 Cu phases. The optical microscopy and scanning electron microscopy results show that the microstructures of rapidly solidified ribbons are clearly different from their ingot alloy. Al-10Ni-5.6Cu ribbons reveal a very fine cellular structure with intermetallic Al 3 Ni particles. Moreover, at high solidification rates the melt-spun ribbons have a polygonal structure dispersed in a supersaturated aluminum matrix. The differential scanning calorimetry measurements revealed that exothermic reaction was between 290 deg. C and 440 deg. C which are more pronounced in the ternary Al-10Ni-5.6Cu alloy.

75 FR 65236 - Security Zone, in the Vicinity of the Michoud Slip Position 30°0′34.2″ N, 89°55′40.7″ W to...

Science.gov (United States)

2010-10-22

...-AA87 Security Zone, in the Vicinity of the Michoud Slip Position 30[deg]0'34.2'' N, 89[deg]55'40.7'' W to Position 30[deg]0'29.5'' N, 89[deg]55'52.6'' W AGENCY: Coast Guard, DHS. ACTION: Temporary final... the entire slip from position 30[deg]0'34.2'' N, 89[deg]55'40.7'' W to position 30[deg]0'29.5'' N, 89...

A 2500 deg2 CMB Lensing Map from Combined South Pole Telescope and Planck Data

International Nuclear Information System (INIS)

Omori, Y.; Chown, R.; Simard, G.; Story, K. T.; University of Chicago, IL

2017-01-01

Here, we present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and Planck temperature data. The 150 GHz temperature data from the 2500 deg 2 SPT-SZ survey is combined with the Planck 143 GHz data in harmonic space to obtain a temperature map that has a broader ℓ coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential C L ϕϕ , and compare it to the theoretical prediction for a ΛCDM cosmology consistent with the Planck 2015 data set, finding a best-fit amplitude of 0.95 −0.06 +0.06 (stat.) −0.01 +0.01 (sys.). The null hypothesis of no lensing is rejected at a significance of 24σ. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, C L ϕG , between the SPT+Planck lensing map and Wide-field Infrared Survey Explorer (WISE) galaxies. We fit C L ϕG to a power law of the form p L =a(L/L 0 ) −b with a, L 0, and b fixed, and find η ϕG =C L ϕG /p L =0.94 −0.04 +0.04 , which is marginally lower, but in good agreement with η ϕG =1.00 −0.01 +0.02 , the best-fit amplitude for the cross-correlation of Planck-2015 CMB lensing and WISE galaxies over ~67% of the sky. Finally, the lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey, whose footprint nearly completely covers the SPT 2500 deg 2 field.

Redox Reaction in Silicate Melts Monitored by ''Static'' In-Situ Fe K-Edge XANES up to 1180 deg. C

International Nuclear Information System (INIS)

Wilke, Max; Partzsch, Georg M.; Welter, Edmund; Farges, Francois

2007-01-01

A new experimental setup to measure in-situ kinetics of redox reactions in silicate melts is presented. To study the progress of the Fe-redox reaction, the variation of the signal is recorded at an energy, where the difference between the spectra of the oxidized and reduced Fe in the melt is largest (''static XANES''). To control the redox conditions, the gas atmosphere could be changed between to types of gases using computer-controlled valves (N2:H2 and air, respectively). In this way, a number of reduction/oxidation cycles can be monitored in-situ and continuously. Applied at the Fe K-edge in molten silicates, we obtained a set of high quality data, which includes the very first steps of the redox reaction. An Avrami-type equation is used to investigate rate-controlling parameters for the iron oxidation/reduction kinetics for two melts (basaltic and Na trisilicate) for temperatures up to 1180 deg. C

Contribution to the study of corrosion of zirconium and zircaloy-2 in superheated steam at 400 deg C (105 kg /cm{sup 2}); Contribution a l'etude de la corrosion du zirconium et du zircaloy-2 dans la vapeur d'eau surchauffee a 400 deg C (105 kg /cm{sup 2})

Energy Technology Data Exchange (ETDEWEB)

Coriou, H; Gauduchau, J; Grall, L; Hure, J; Pelras, M [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

The corrosion kinetics of zircaloy-2 in water and steam at temperatures between 300 deg. C and 400 deg. C are represented by a curve sharply divided into two stages separated by a so-called transition point. After a first period of decreasing corrosion rate there follows a second period with much faster kinetics in which the speed is constant. After carrying out a methodical study of the corrosion of 'zircaloy-2 in the form of sheets and tubes. We have demonstrated, at 400 deg. C in steam, a systematic anomaly which appears at the transition point. The curve presents three quite distinct points; after the first period a fast corrosion is observed, followed by a third period at a slower speed. This leads us to believe that there may be not a single point but a transition zone, separating two types of kinetic behaviour and corresponding to modifications in the properties of the oxide layer. After this readjustment period a new corrosion law is established, lasting a considerable time, the corrosion speed being slower than that indicated so far. A study of the morphology of the oxide films which develop under these conditions has demonstrated the special part played by mechanical, physical and metallurgical factors in the case of zirconium. Deep penetration of oxide can thus show up on the inner wall of hammer-hardened tubes. Simultaneously a very considerable hydride formation occurs in the metal. (author) [French] La cinetique de corrosion du zircaloy-2 dans l'eau et la vapeur a des temperatures comprises entre 300 et 400 deg. C est representee par une courbe a deux periodes separees par un point singulier appele point de transition. A une premiere periode a vitesse de corrosion decroissante, succede une deuxieme periode a cinetique beaucoup plus rapide dont la vitesse est constante. Apres une etude systematique de la corrosion du zircaloy-2 sous forme de toles et de tubes, nous avons mis en evidence a 400 deg. C, dans la vapeur, une anomalie systematique qui se

Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 8 deg to 90 deg. 1: Low-wing model A. [fluid flow and vortices data for general aviation aircraft to determine aerodynamic characteristics for various designs

Science.gov (United States)

Hultberg, R. S.; Mulcay, W.

1980-01-01

Aerodynamic characteristics obtained in a rotational flow environment utilizing a rotary balance are presented in plotted form for a 1/5 scale, single engine, low-wing, general aviation airplane model. The configuration tested included the basic airplane, various control deflections, tail designs, fuselage shapes, and wing leading edges. Data are presented without analysis for an angle of attack range of 8 to 90 deg and clockwise and counterclockwise rotations covering a range from 0 to 0.85.

Studies on the position of canines, premolars and molars by 450 .deg. oblique lateral cephalography

Energy Technology Data Exchange (ETDEWEB)

Ahn, Hyung Kyu [Department of Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

1976-11-15

This study was done using the 45 .deg. oblique lateral cephalograms of 20 year old, 18 male and 27 female, with normal occlusion, on canines, premolars, premolars and molars on upper and lower jaws. Axial inclination to nasal floor, occlusal plane and mandibular plane, and inter-axial inclination were examined. In addition the position of each tooth was examined in height and depth in upper and lower jaws. The results were obtained as follows; 1. The inclination of long axis of upper lst premolar was most nearly perpendicular, upper canine was tilted mesially, and 2nd premolar and molars were tilted distally. 2. The inclination of long axis of lower molars were tilted mesially. 3. There were no severe variation on the inter-axial inclination of canine to 2nd molar.

Studies on the position of canines, premolars and molars by 450 .deg. oblique lateral cephalography

International Nuclear Information System (INIS)

Ahn, Hyung Kyu

1976-01-01

This study was done using the 45 .deg. oblique lateral cephalograms of 20 year old, 18 male and 27 female, with normal occlusion, on canines, premolars, premolars and molars on upper and lower jaws. Axial inclination to nasal floor, occlusal plane and mandibular plane, and inter-axial inclination were examined. In addition the position of each tooth was examined in height and depth in upper and lower jaws. The results were obtained as follows; 1. The inclination of long axis of upper lst premolar was most nearly perpendicular, upper canine was tilted mesially, and 2nd premolar and molars were tilted distally. 2. The inclination of long axis of lower molars were tilted mesially. 3. There were no severe variation on the inter-axial inclination of canine to 2nd molar.

Equation of state of solid hydrogen at 0 deg K. A bibliography

International Nuclear Information System (INIS)

Masse, J.-L.

1976-02-01

A bibliography on solid hydrogen at 0 deg K and its equation of state is presented. The isotopic derivatives of H 2 , such as D 2 , HD... have been also considered. Both phases of solid hydrogen have been studied: the molecular phase, stable at low pressure, and the hypothetical metallic phase which must be stable at high pressure. The study of the molecular phase is preceded by a study of the (H 2 ,H 2 ) system of two interacting H 2 , molecules, the knowledge of this interaction being necessary for the evaluation of the properties of the molecular solid phase. The three systems: (H 2 ,H 2 ) and molecular solid and metallic hydrogen have been considered from the experimental and theoretical points of view. The properties of these systems, the measurement or the calculation of which are described, have been chosen on account of their usefulness for the research of the equation of state of molecular or metallic solid hydrogen. Different interaction potentials of two hydrogen molecules and different equations of state of molecular solid hydrogen are given. Some theoretical studies are proposed [fr

Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 20 to 90 deg. 3: Influence of control deflection on predicted model D spin modes

Science.gov (United States)

Ralston, J. N.; Barnhart, B. P.

1984-01-01

The influence of control deflections on the rotational flow aerodynamics and on predicted spin modes is discussed for a 1/6-scale general aviation airplane model. The model was tested for various control settings at both zero and ten degree sideslip angles. Data were measured, using a rotary balance, over an angle-of-attack range of 30 deg to 90 deg, and for clockwise and counter-clockwise rotations covering an omegab/2V range of 0 to 0.5.

One spin pion asymmetry in d ↑ + A → π+- + X processes near θπ = 90 deg

International Nuclear Information System (INIS)

Averichev, G.S.; Agakishev, G.A.; Borzunov, Yu.T.

1996-01-01

The results of the measurements of the vector analyzing power of inclusive pions produced in the reactions of polarized deuterons with different (H and C) targets near 90 deg at incident beam momenta from 3 to 9 GeV/c are presented. The large values of the vector analyzing power and the different sings of the π + and π - asymmetries have been observed in the d ↑ + H → π +- +... reactions for a pion momentum in the range 300-350 MeV/c. The results of Monte Carlo simulations indicate the strong influence of the intermediate Δ-resonances on the value and the sing of the analyzing power [ru

Solubility diagrams in ternary aqueous-salt systems with yttrium, barium and copper nitrates at 25 deg C

International Nuclear Information System (INIS)

Petrenko, S.V.; Lyashchenko, A.K.; Karataeva, I.M.; Mozhaev, A.P.

1990-01-01

Solubility diagrams in Cu(NO 3 ) 2 -Y(NO 3 ) 3 -H 2 O, Y(NO 3 ) 3 -Ba(NO 3 ) 2 -H 2 O and Cu(NO 3 ) 2 -Ba(NO 3 ) 2 -H 2 O systems are studied at 25 deg C based on experimental determinations of salt solubility, isopiestic measurements and data of the calculation-experimental method in the framework of the Pitzer model. Binary and ternary parameters of interionic interactions are calculated; applicability of the method to the given systems is shown. Salts of complex composition and structure are absent in them; mutual salting out of components is also observed

Observations of a quasi-coherent fluctuation mode in the KT-5C tokamak during -90 deg. phase shift feedback

International Nuclear Information System (INIS)

Zhai Kan; Wen Yizhi; Yu Changxuan; Liu Wandong; Wan Shude; Zhuang Ge; Yu Wen; Xu Zhizhan

1997-01-01

A new fluctuation phenomenon is observed through Langmuir probe measurements at the edge plasma in the KT-5C tokamak by applying a -90 deg. phase shift feedback. Using a two point correlation technique, it is found that this fluctuation mode has a longer poloidal wavelength and a definite frequency when compared with the usual edge turbulence. It is also found through bispectral analysis that this mode is a spontaneously excited quasi-coherent mode, which has almost no contribution to the cross-field particle flux. (author)

Chipping quality of γ-irradiated potatoes of three Indian cultivars stored at 8, 12 and 16 degC

International Nuclear Information System (INIS)

Ezekiel, R.; Singh, B.; Datta, P.S.

2008-01-01

Potatoes of cultivars Kufri Chandramukhi, Kufri Jyoti and Kufri Chipsona-2 were irradiated with 0.1 and 0.5 kGy γ-rays and stored at 8, 12 and 16 degC and 85-90% RH for 180 days, with CIPC (isopropyl N-(3-chlorophenyl) carbamate) treatment as control. Irradiation increased weight loss and rotting compared to control. There was little change in the dry matter content due to irradiation up to 120 days of storage (DOS) but increased significantly at 180 DOS. The reducing sugar content increased by 18-35% with irradiation and resulted in increased browning of potato chips prepared. There was a significant difference in reducing sugar content and chip colour, between 0.1 and 0.5 kGy irradiation. Irradiation also caused 20-29% increase in sucrose content. Compared to control, free amino acids and phenols content increased with irradiation but there was no significant difference between 0.1 and 0.5 kGy. Amongst the cultivars, Kufri Chipsona-2 showed higher weight loss and rotting, which increased further with irradiation, and increase in storage temperature and duration. (author)

Métodos para atrair e repelir a abelha Apis mellifera (L. em cultura de maracujá amarelo (Passiflora edulis flavicarpa flavicarpa Deg. - DOI: 10.4025/actascianimsci.v25i1.2036 Methods to attract and repel Africanize honey bees Apis mellifera, L., to passion fruit (Passiflora edulis flavicarpa flavicarpa Deg. - DOI: 10.4025/actascianimsci.v25i1.2036

Directory of Open Access Journals (Sweden)

Marta Maria Rossi

2003-04-01

Full Text Available Este experimento foi conduzido no Centro Universitário Moura Lacerda, Campus Ribeirão Preto, Estado de São Paulo, e teve como objetivos observar a eficiência dos extratos de capim-limão (Cymbopogon citratus, manjericão (Ocimum basilicum L. e falsa melissa (Lippia alba, como atrativos, e citronela (C. nardus, extratos de orégano, pimenta-do-reino, canela e cravo, como repelentes, que foram comparados a outros atrativos (eugenol e linalol e repelentes (n.octyl.acetato, 2.heptanona e citronellal, obtidos comercialmente, para a A. mellifera. Foram estudados, ainda, os insetos visitantes nas flores do maracujá amarelo (Passiflora edulis f. flavicarpa Deg., além de testar plantas-iscas para essas abelhas. Os produtos testados in vitro e, posteriormente, testados tanto pulverizados quanto em tubos, não foram eficientes para atrair ou repelir a abelha Apis mellifera. Os produtos n.octyl.acetato e citronellal repeliram completamente tanto as abelhas africanizadas quanto as Xylocopa, não devendo ser utilizado em cultivos comerciais. O girassol (Hellianthus annuus e o cosmos (Cosmos sulphureus podem ser utilizados como alternativas para afastar a abelha A. mellifera das flores do maracujá.This experiment was carried out at Centro Universitário Moura Lacerda, Ribeirão Preto, state of São Paulo, Brazil, to study Africanized honey bee (Apis mellifera L. attractives and repellents in vitro, in tubes and on passion fruit flowers (Passiflora edulis flavicarpa flavicarpa Deg.. Visiting insects were studied in flowers and also, bait-plants to Africanized honey bees were tested. The products were not effective in attracting and repelling the honey bee in vitro and in tube tests. The chemicals n.octyl.acetato and citronellal were repellent to honey bees and Xylocopa bees on passion fruit flowers. Sunflower (Hellianthus annuus and cosmos (Cosmos sulphureus flowers can be used to remove Africanized honey bees from passion fruit crops.

The Cs2SO4-Ce2(SO4)3-H2SO4-H2O system at 150 and 200 deg C

International Nuclear Information System (INIS)

Bondar', S.A.; Belokoskov, V.I.; Trofimov, G.V.

1982-01-01

Solubility in the system Cs 2 SO 4 -Ce 2 (SO 4 ) 3 -H 2 SO 4 -H 2 O using the isothermal method at 150 and 200 deg C at molar ratios Cs 2 SO 4 :Ce 2 (SO 4 ) 3 =1:5 and conditions of sulfate crystallization Cs 2 SO 4 xCe 2 (SO 4 ) 3 , Ce 2 (SO 4 ) 3 x0.5H 2 SO 4 xnH 2 O (n=2-3) and Ce 2 (SO 4 ) 3 x3H 2 SO 4 are determined. Double sulfate Cs 2 SO 4 xCe 2 (SO 4 ) 3 is studied using the methods of crystallooptical, thermal, X-ray phase analyses and IR spectroscopy

On minimal energy Hartree-Fock states for the 2DEG at fractional fillings

International Nuclear Information System (INIS)

Cabo Montes Oca, A. de.

1995-08-01

Approximate minimal energy solutions of the previously discussed general class of Hartree-Fock (HF) states of the 2DEG at 1/3 and 2/3 filling factors are determined. Their selfenergy spectrum is evaluated. Wannier states associated to the filled Bloch states are introduced in a lattice having three flux quanta per cell. They allow to rewrite approximately the ν = 1/3 HF Hamiltonian as sum of three independent tight-binding model Hamiltonians, one describing the dynamics in the band of occupied states and the other ones in the tow bands of excited states. The magnitude of the hopping integral indicates the enhanced role which should have the correlation energy in the present situation with respect to the case of the Yoshioka and Lee second order energy calculation for the lowest energy HF state. Finally, the discussion also suggests the Wannier function, which spreads an electron into a three quanta area, as a physical model for the composite fermion mean field one particle state. (author). 11 refs, 5 figs

Oxidation of nuclear fuel below 400 deg. Consequence on long-term dry storage

International Nuclear Information System (INIS)

Dehaudt, Ph.

2000-01-01

This document reviews the status of the knowledge on the oxidation of fuels below 400 deg C, in all its forms, including fuel rods, by examining the consequences of this reaction on the strength or ruin of the fuel rods during dry storage in air for a hundred years. The data available in the scientific literature, and the data acquired by CEA, are abundant on irradiated powders and pellets, but sparser for irradiated fuel fragments and for rods or sections of fuel rods. A bibliographic review is made to identify the morphological and structural changes, as well as the kinetic laws. An analysis and a summary is made with a concern to evaluate the risks of rod ruin by oxidation. The final section, in a few pages, addresses the essential lessons from this study. It presents: first, a summary of the main results of this review and its analysis, recommendations and remedies for storage; proposed research guidelines as well as precise topics, in order to fill out our knowledge and, even better, to identify the acceptable limits for storage. (author)

An Improved Micropropagation Protocol by Ex Vitro Rooting of Passiflora edulis Sims. f. flavicarpa Deg. through Nodal Segment Culture.

Science.gov (United States)

Shekhawat, Mahipal S; Manokari, M; Ravindran, C P

2015-01-01

A procedure for rapid clonal propagation of Passiflora edulis Sims. f. flavicarpa Deg. (Passifloraceae) has been developed in this study. Nodal explants were sterilized with 0.1% HgCl2 and inoculated on Murashige and Skoog (MS) basal medium. The addition of 2.0 mgL(-1) 6-benzylaminopurine (BAP) to MS medium caused an extensive proliferation of multiple shoots (8.21 ± 1.13) primordial from the nodal meristems. Subculturing of these multiple shoots on the MS medium augmented with 1.0 mgL(-1) of each BAP and Kinetin (Kin) was successful for the multiplication of the shoots in vitro with maximum numbers of shoots (25.73 ± 0.06) within four weeks of incubation. Shoots were rooted best (7.13 ± 0.56 roots/shoots) on half strength MS medium supplemented with 2.0 mgL(-1) indole-3 butyric acid (IBA). All in vitro regenerated shoots were rooted by ex vitro method, and this has achieved 6-7 roots per shoot by pulsing of cut ends of the shoots using 200 as well as 300 mgL(-1) IBA. The plantlets were hardened in the greenhouse for 4-5 weeks. The hardened plantlets were shifted to manure containing nursery polybags after five weeks and then transferred to a sand bed for another four weeks for acclimatization before field planting with 88% survival rate.

OMI/Aura Multi-wavelength Aerosol Optical Depth and Single Scattering Albedo Daily L2 Global 0.25x0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The second release of Collection 3 OMI/Aura level-2G daily global gridded (0.25x0.25 deg) Aerosol data product OMAEROG (Version 003 has been made available to the...

OMI/Aura Near UV Aerosol Optical Depth and Single Scattering Albedo Daily L2 Global 0.25x0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI-Aura level-2G daily global gridded (0.25x0.25 deg) near-UV Aerosol data product OMAERUVG based on the enhanced algorithm is available from the NASA Goddard...

Annealing effects on structural and electrical properties of Ru/Au on n-GaN Schottky contacts

International Nuclear Information System (INIS)

Reddy, V. Rajagopal; Rao, P. Koteswara; Ramesh, C.K.

2007-01-01

Thermal annealing effects on electrical and structural properties of Ru/Au Schottky contact to n-type GaN (n d = 4.07 x 10 17 cm -3 ) have been investigated using current-voltage (I-V), capacitance-voltage (C-V), Auger electron spectroscopy (AES) and X-ray diffraction (XRD). The Schottky barrier height of the as-deposited sample was found to be 0.75 eV (I-V) and 0.93 eV (C-V), respectively. It is noted that the barrier height increased when the contact was annealed at 300 deg. C and slightly decreased upon annealing at temperatures of 400 deg. C and 500 deg. C. The extracted Schottky barrier heights are 0.99 eV (I-V), 1.34 eV (C-V) for 300 deg. C, 0.88 eV (I-V), 1.20 eV (C-V) for 400 deg. C and 0.72 eV (I-V), 1.08 eV (C-V) for 500 deg. C annealed contacts, respectively. Further it is observed that annealing results in the improvement of electrical properties of Ru/Au Schottky contacts. Based on Auger electron spectroscopy and X-ray diffraction studies, the formation of gallide phases at the Ru/Au/n-GaN interface could be the reason for the improvement of electrical characteristics upon annealing at elevated temperatures

Produção de etileno e atividade da enzima ACCoxidase em frutos de maracujá-amarelo (Passiflora edulis f. flavicarpa Deg. Ethylene production and ACCoxidase activity in passion fruits (Passiflora edulis f. flavicarpa Deg.

Directory of Open Access Journals (Sweden)

Larissa Macedo Winkler

2002-12-01

Full Text Available O maracujá-amarelo (Passiflora edulis f. flavicarpa Deg. é uma das principais espécies cultivadas do gênero Passiflora. Seus frutos são ricos em minerais, vitaminas e apresentam aroma e sabor agradáveis. O presente trabalho teve como objetivos determinar a produção de etileno e atividade enzimática da ACCoxidase (ACCO em maracujá-amarelo colhido em diferentes estádios de maturação. A determinação do estádio de maturação foi realizada com o auxílio de um colorímetro, que, por meio da radiação ultravioleta, estabeleceu valores absolutos da cor dos frutos de cada um dos grupos (I, II e III. A produção de etileno e a atividade da ACCoxidase foram realizadas por cromatografia gasosa. Os frutos do grupo I são predominantemente verdes, de acordo com os valores absolutos da cor obtidos. Os frutos do grupo II são predominantemente, coloridos, ou seja, em um estádio de maturação intermediário, e os frutos do grupo III, totalmente coloridos, apresentando-se, portanto, em início da senescência. Os frutos do grupo I apresentaram atividade da ACCO predominantemente mais elevada do que os frutos do grupo III, ocorrendo também o mesmo comportamento com a produção de etileno, com um valor médio de 7,25 nL. g-1. h-1, bem acima do nível máximo estabelecido para espécies classificadas como fracamente produtoras de etileno (0,5 nL. g-1. h-1. Assim, o maracujá-amarelo difere quanto à produção de etileno e atividade da enzima ACCO, de acordo com o estádio de maturação. A espécie foi considerada, em comparação com outras espécies, como produtora intermediária de etileno. A atividade enzimática da ACCO é mais elevada em frutos predominantemente verdes, mas ela é limitada e necessita de co-fatores enzimáticos para sua atividade máxima.Passion fruit (Passiflora edulis f. flavicarpa Deg. is one of the main cultivated species of Passiflora genus. Its fruits are rich in mineral salts and vitamins and to present

Simulation of creep test on 316FR stainless steel in sodium environment at 550degC

International Nuclear Information System (INIS)

Satmoko, A.; Asayama, Tai

1999-04-01

In sodium environment, material 316FR stainless steel risks to suffer from carburization. In this study, an analysis using a Fortran program is conducted to evaluate the carbon influence on the creep behavior of 316FR based on experimental results from uni-axial creep test that had been performed at temperature 550degC in sodium environment simulating Fast Breeder Reactor condition. As performed in experiments, two parts are distinguished. At first, elastic-plastic behavior is used to simulate the fact that just before the beginning of creep test, specimen suffers from load or stress much higher than initial yield stress. In second part, creep condition occurs in which the applied load is kept constant. The plastic component should be included, since stresses increase due to section area reduction. For this reason, elastic-plastic-creep behavior is considered. Through time carbon penetration occurs and its concentration is evaluated empirically. This carburization phenomena are assumed to affect in increasing yield stress, decreasing creep strain rate, and increasing creep rupture strength of material. The model is capable of simulating creep test in sodium environment. Material near from surface risks to be carburized. Its material properties change leading to non-uniform distribution of stresses. Those layers of material suffer from stress concentration, and are subject to damage. By introducing a damage criteria, crack initialization can thus be predicted. And even, crack growth can be evaluated. For high stress levels, tensile strength criterion is more important than creep damage criterion. But in low stress levels, the latter gives more influence in fracture. Under high stress, time to rupture of a specimen in sodium environment is shorter than in air. But for stresses lower than 26 kgf/mm 2 , the time to rupture of creep in sodium environment is the same or little longer than in air. Quantitatively, the carburization effect at 550degC is not important. This

Transonic Aerodynamic Characteristics of a Wing-Body Combination having a 52.5 deg Sweptback Wing of Aspect Ratio 3 with Conical Camber and Designed for a Mach Number of the Square Root of 2

Science.gov (United States)

Igoe, William B.; Re, Richard J.; Cassetti, Marlowe

1961-01-01

An investigation has been made of the effects of conical wing camber and supersonic body indentation on the aerodynamic characteristics of a wing-body configuration at transonic speeds. Wing aspect ratio was 3.0, taper ratio was 0.1, and quarter-chord line sweepback was 52.5 deg with airfoil sections of 0.03 thickness ratio. The tests were conducted in the Langley 16-foot transonic tunnel at various Mach numbers from 0.80 to 1.05 at angles of attack from -4 deg to 14 deg. The cambered-wing configuration achieved higher lift-drag ratios than a similar plane-wing configuration. The camber also reduced the effects of wing-tip flow separation on the aerodynamic characteristics. In general, no stability or trim changes below wing-tip flow separation resulted from the use of camber. The use of supersonic body indentation improved the lift-drag ratios at Mach numbers from 0.96 to 1.05.

Mass and energy balance: application to the sanitary sewage treatment with an upflow anaerobic sludge blanket (UASB) reactors to temperature of 20 deg C; Balanco de massa e energia: aplicacao ao tratamento de esgotos sanitarios com reatores anaerobicos de manta de lodo (UASB) a temperatura de 20 deg C

Energy Technology Data Exchange (ETDEWEB)

Carrasco, Katherine Ivonne Alcocer

1992-07-01

A feasibility study of an Upflow Anaerobic Sludge Blanket (UASB) reactor use as a sewage treatment plant component for areas with average temperature bellow 20 deg C was performed. The literature on UASB reactor indicates that a 70 % chemical oxygen demand (COD) removal al 20 and 6 to 17 hr hydraulic detention time is possible in sewage treatment plants. This study was developed for a Oruro (Bolivia) district and the plant was designed for a population of up to 10,000 inhabitants. This city presents average temperatures lower than 20 deg C being necessary to heat the sewage if is used the UASB reactor. Based on the performance simulation of mass and energy balances it was found that 84 % COD removal and 92 % total suspended solids removal are possible. The potential average energy production (61 kW due to methane combustion) is less than 10 % of the power consumption for heating, which indicates that the use of the methane may be expensive. The evaluated energy rate to be applied to the sewage for heating is 0.33 kW/m{sup 3} d{sup -1} which is significantly greater than the necessary energy to introduce oxygen in aerobic treatment systems. However total energy demand for aerobic systems must be evaluated for each particular case. (author)

Local heat/mass transfer distributions around sharp 180 deg turns in two-pass smooth and rib-roughened channels

Science.gov (United States)

Han, J. C.; Chandra, P. R.; Lau, S. C.

1988-01-01

The napthalene sublimation technique was employed to study the detailed mass transfer distributions around the sharp 180 deg turns in a two-pass, square, smooth channel and in an identical channel with two rib-roughened opposite walls. Experiments conducted for Reynolds numbers of 15,000, 30,000, and 60,000 indicate that the Sherwood numbers on the top, outer, and inner walls around the turn in the rib-roughened channel are higher than the corresponding Sherwood numbers around the turn in the smooth channel. Sherwood numbers after the sharp turn are found to be higher than those before the turn for both the smooth and the ribbed channels.

Environmental fatigue behaviors of wrought and cast stainless steels in 310degC deoxygenated water

International Nuclear Information System (INIS)

Cho, Pyung-Yeon; Jang, Hun; Jang, Changheui; Jeong, Ill-Seok; Lee, Jae-Gon

2009-01-01

Environmental fatigue behaviors of wrought type 316LN stainless steel and cast CF8M stainless steel were investigated. Low cycle fatigue tests were performed in a 310degC deoxygenated water environment at a strain rate of 0.04%/s with various strain amplitudes. It was shown that the low cycle fatigue life of CF8M was slightly longer than that of 316LN. To understand the causes of the difference, fracture surface was observed and material factors like microstructure, mechanical properties, and chemical compositions of both materials were analyzed. In a duplex microstructure of CF8M, the fatigue crack growth was affected by barrier role of ferrite phase and acceleration role of microvoids in ferrite phase. Test results indicate that the former is greater than the latter, resulting in slower fatigue crack growth rate, or longer LCF lives in CF8M than in 316LN. (author)

Endovascular treatment of splenic artery aneurysms; Trattamento endovascolare degli aneurismi dell'arteria splenica

Energy Technology Data Exchange (ETDEWEB)

Lagana, Domenico; Carrafiello, Gianpaolo; Mangini, Monica; Fontana, Federico; Dizonno, Massimiliano; Fugazzola, Carlo [Insubria Univ., Varese (Italy). Cattedra di radiologia; Castelli, Patrizio [Insubria Univ., Varese (Italy). Chirurgia vascolare

2005-07-15

Purpose. To assess the feasibility and effectiveness of endovascular treatment of splenic artery aneurysm (SAAs). Materials and methods. Between May 2000 and June 2003 we treated 11 true SAAs in 9 patients (7 females and 2 males; mean age 58 years), 8 saccular and 3 fusiform, 4 located at the middle tract of the splenic artery, 5 at the distal tract and 2 intra-parenchymal. The diagnosis was performed with colour-Doppler ultrasound and/or CT-angiography; 7 patients were symptomless, 1 had left hypochondriac pain, and 1 had acute abdomen caused by a ruptured SAA. Four SAAs were treated by micro coil embolisation of the aneurysmal sac with preservation of splenic artery patency; in 2 cases this was associated with transcatheter injection of N-butyl-2-cyanoacrylate. Four cases were treated by endovascular ligature, with sectoral spleen ischaemia. One ruptured SAA received emergency treatment with splenic artery cyanoacrylate embolisation. Two intra-parenchymal SAAs were excluded, one by cyanoacrylate embolisation of the afferent artery and the other by transcatheter thrombin injection in the aneurysmal sac. Results. Technical success was observed in all cases (in 10/11 at the end of the procedure; in 1/11 at CT performed 3 days after the procedure). The follow-up (mean 18 months; range 6-36) was performed by colour-Doppler ultrasound and/or CT-angiography 3, 6 and 12 months after the procedure and subsequently once a year; the complete exclusion of the aneurysms was confirmed in 11/11 cases. The complications were: 4 cases of mild pleuritis; fever and left hypochondriac pain 1 day after the procedure (in the same 4 patients and in one other case); 5 cases of sectorial spleen ischaemia and 1 case of diffuse spleen infarction with partial revascularization by collateral vessels. No alteration of the levels of pancreatic enzymes was found; a transitory increase in platelet count occurred only in the patient with diffuse spleen infarction. Conclusions. Using different

The TL and room temperature OSL properties of the glow peak at 110 deg. C in natural milky quartz: A case study

International Nuclear Information System (INIS)

Polymeris, George S.; Afouxenidis, Dimitrios; Tsirliganis, Nestor C.; Kitis, George

2009-01-01

The LM-OSL signal of quartz, while measured at room temperature, is dominated by an intermediate, broad and intense OSL component, so that its contribution and general characteristics are derived very accurately. Through a series of dose-response, bleaching and thermal decay at room temperature experiments, in conjunction with curve fitting studies, a component resolved analysis is carried out studying the correlation between this specific component, termed as LM-OSL component C 2 and the 110 deg. C TL glow peak in quartz. The dose-response of these two luminescence components behaves exactly similar being linear at low doses and saturating at almost 100 Gy. Both signals decay exponentially under illumination, providing identical optical detrapping cross-section values. Residual of both luminescence signals after thermal decay at room temperature follows an exponential law, yielding similar mean half-lives. All previous luminescence features provide strong evidence for the electron trap being the same for both the 110 deg. C TL trap and the LM-OSL component C 2 . The results of the present work are very promising and clearly support the possibility of extrapolating the TL pre-dose methodology to the OSL pre-dose effect using only the LM-OSL component C 2

Structural evolution of Fe-18Ni-16Cr-4Al steel during aging at 950 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Wang, Man; Jang, Jinsung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Zhou, Zhangjian [School of Materials Science and Engineering, USTB, Beijing (China)

2015-05-15

Austenitic stainless steels are also among important structural materials for in-core components of nuclear reactors, and the performance, the oxidation resistance as well as the mechanical strength at high temperature are further expected after Fukushima accident. Alumina-forming austenitic (AFA) steel was first developed by Y. Yamamoto et al. , which showed a good combination of oxidation resistance and creep resistance. The strengthening is achieved through nano-sized MX and Laves. Microstructural evolution of Fe-18Ni-16Cr-4Al during aging at 950 .deg. C was studied. This steel consists of two phases of austenite and ferrite. During aging, needle-shaped NiAl precipitates in austenite, while round shaped NiAl form in ferrite, which is supposed to be due to different crystal structural parameters.

Synthesis of ceramic powders of La9,56 (SiO4)6O2,34 and La9,8Si5,7MgO,3O26,4 by modified sol-gel process

International Nuclear Information System (INIS)

Lira, Sabrina Lopes; Paiva, Mayara Rafaela Soares; Misso, Agatha Matos; Elias, Daniel Ricco; Yamagata, Chieko

2012-01-01

Lanthanum silicate oxyapatite materials are promising for application as electrolyte in solid oxide fuel cells because of high ionic conductivity at temperatures between 600 deg C and 800 deg C. In this work, oxyapatites with the composition La 9,56 (SiO 4 ) 6 O 2,34 , and La 9,8 Si 5,7 Mg 0,3 O 26,4 were synthesized by using the sol-gel method, followed by precipitation. Initially, the gel of silica was synthesized from sodium silicate solution, by acid catalysis using lanthanum and magnesium chloride solution. Then, the La and Mg hydroxides were precipitated with NaOH in the gel. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and measurements of specific surface area. The crystalline oxyapatite phase of La 9,56 (SiO 4 ) 6 O 2,34 , and was La 9,8 Si 5,7 Mg 0,3 O 26,4 obtained by calcination at 900 deg C for 2 and 1h respectively (author)

Discussion on miner's rule in type 304 stainless steel in air at 288degC

International Nuclear Information System (INIS)

Hayashi, Makoto

1997-01-01

The effect of fluctuating stress on the fatigue strength of type 304 stainless steel in air at 288degC was examined. In any of the 2 step increasing stress, 2 step decreasing stress, repeated 2 step stress (high to low), repeated 2 step stress (low to high) and gradual increasing stress, the cumulative usage factor calculated based on the linear damage law exceeds 1. In the 2 step increasing or decreasing stress, the usage factor for the decreasing stress type is larger than the increasing stress type. On the other hand, the cumulative usage factor for the repeated 2 step stress (low to high) is larger than the repeated 2 step stress (high to law), and the usage factor increases with increasing number of cycles at the first stress. The smaller the difference between the first stress and the second stress, the larger the usage factor. In the gradual increasing stress, the usage factor increases with increasing number of cycles at each stress. (author)

Saints' Relics in Scuola di S. Giorgio degli Schiavoni: An Anti-Ottoman Pantheon

Directory of Open Access Journals (Sweden)

Ana Marinković

2018-04-01

Full Text Available The intensified military campaigns against the Ottomans in the second half of the fifteenth century palpably influenced the cult of saints venerated in Scuola di S. Giorgio degli Schiavoni, both by assimilating new saints, as well as strenghtening the existing cults through indulgences and relic acquisitions. The initial pair of patron saints – St George and St Tryphon, the city patrons of Bar and Kotor – delineated the geographical area where the majority of confraternity members originated from, that is, the Venetian Albania. The inclusion of St Jerome, the patron of Dalmatia, to the confraternal pantheon by Cardinal Bessarion's indulgence issued in 1464, in addition to rounding up the holy patronage to all the Eastern Adriatic Venetian dependencies, also marked the beginning of a strong anti-Ottoman motivation in the scuola's hagiographic horizon. The triple endowment of the Scuola in 1502 – relic acquisition, granting of indulgence, and commission of Carpaccio's monumental cycle – continued to work on the same line, and added to the practical aspect of spiritual support to the members of Venetian troops provenient of the Eastern Adriatic. However, the saints whose relics are today kept in the altar of the lower hall, including the patron saint of the Republic of Dubrovnik, point to an even wider devotional agenda, possibly arranged after the Battle of Lepanto, as the comparative analysis of the reliquaries show.   Le campagne militari contro gli Ottomani intensificatesi nella seconda metà del XV secolo influenzarono palesemente il culto dei santi venerati nella Scuola di S. Giorgio degli Schiavoni, sia attraverso l'assimilazione di nuovi santi, sia tramite il rafforzamento del culto già esistente verso le indulgenze e l'impulso all'acquisizione di reliquie. La prima coppia di santi patroni - San Giorgio e San Trifone, patroni della città di Bar e Cattaro - delimitano l'area geografica da cui proviene la maggior parte dei membri

Morphology and electronic transport of polycrystalline silicon films deposited by SiF sub 4 /H sub 2 at a substrate temperature of 200 deg. C

CERN Document Server

Hazra, S; Ray, S

2002-01-01

Undoped and phosphorous doped polycrystalline silicon (poly-Si) films were deposited using a SiF sub 4 /H sub 2 gas mixture at a substrate temperature of 200 deg. C by radio frequency plasma enhanced chemical vapor deposition (rf-PECVD). Fourier transform infrared (FTIR) spectroscopy and x-ray diffraction (XRD) experiments reveal that the present poly-Si films are equivalent to the poly-Si films deposited at high temperature (>600 deg. C). XRD and scanning electron microscope observations show that the crystalline quality of slightly P-doped film is better compared to that of undoped poly-Si films. Phosphorus atom concentration in the slightly P-doped poly-Si film is 5.0x10 sup 1 sup 6 atoms/cm sup 3. Association of a few phosphorous atoms in the silicon matrix enhances crystallization as eutectic-forming metals do. Dark conductivity of slightly P-doped film is 4 orders of magnitude higher, although mobility-lifetime product (eta mu tau) is 2 orders of magnitude lower than that of undoped film. The presence o...

Compact galaxies in the region with the center coordinates 07sup(h)59sup(m)+54 deg 44'

International Nuclear Information System (INIS)

Boerngen, F.; Kalloglyan, A.T.

1980-01-01

A list of 70 compact galaxies is presented, galaxies being found in the metagalactic field in the region with center coordinates αsub(1950)=07sup(h)59sup(m), deltasub(1950)54 deg 44'. The selection of objects have been carried out on negatives obtained in the Schmidt focus of the two-meter universal telescope of Tautenburg observatory in the colour B and V system. Galaxies of the highest surface brightness and of spherical configuration have been included. Only in some cases slightly elongated objects have been included due to their very high surface brightness. The coordinates, B and V stellar values of all objects have been measured. The maps of their identification are presented

Il ruolo degli arbëreshë nella messa a punto del modello albanese di rapporti tra le comunità religiose e lo Stato

Directory of Open Access Journals (Sweden)

Giovanni Cimbalo

2014-05-01

Full Text Available Il contributo, sottoposto a valutazione, riproduce il testo della Comunicazione presentata alla Konferencë Shkencore Ndërkombëtare Albanologjike, Një rilindje para Rilindjes (Gjirokastër, 22 maj 2013 con il titolo albanese Roli i arbëreschë në zhvillimin e modelit shqiptar të marrëdhënieve ndërmjet bashkësive fetare dhe shtetit, ed è destinata alla pubblicazione negli Atti.SOMMARIO: 1. Caratteristiche dell’insediamento delle popolazioni arbëreshë in Italia - 2. Il contributo del pluralismo religioso nella fondazione dello Stato albanese - 3. L’uso degli arbëreshë per l’espansione della Chiesa cattolica a Oriente: un progetto abortito - 4. Considerazioni conclusive.

Oxidation of 5,6-diamino-1,3-dimethyl-2,4-dioxopyrimidine by perrhenate: the crystal structure of 1,3,6,8-tetramethylpyrimidopteridine-2,4,5,7-tetrone

International Nuclear Information System (INIS)

Booysen, Irvin; Gerber, Thomas I.A.; Mayer, Peter

2008-01-01

The oxidation of 5,6-diamino-1,3-dimethyl-2,4-dioxopyrimidine (H 2 ddd) by perrhenate (ReO 4 - ) led to the formation of 1,3-dimethylalloxan, which condenses with unoxidized H 2 ddd to yield the product 1,3,6,8-tetramethylpyrimidopteridine-2,4,5,7-tetrone (tppt). The structure of tppt consists of a central pyrazine ring and two terminal pyrimidine rings in cis positions. The dihedral angles between the pyrazine and pyrimidine rings are 1.08 deg and 1.20 deg. (author)

Buckling measurements up to 250 deg C on lattices of Agesta clusters and on D2O alone in the pressurized exponential assembly TZ

International Nuclear Information System (INIS)

Persson, R.; Andersson, A.J.W.; Wikdahl, C.E.

1966-11-01

Buckling determinations by means of flux mapping were performed in TZ up to 250 deg C on two lattices of Aagesta fuel assemblies in D 2 O and on D 2 O alone. Most of the flux measurements were made with fission counters in pressure thimbles. The perturbations caused by the thimbles were studied experimentally in various ways and compared with two group diffusion-theory calculations. In one of the lattices the effectiveness of a control rod (AglnCd) was also investigated. The results of the diffusion length experiments indicated some systematic error of the order of 0.15 - 0.10/m 2 in the bucklings measured, though the temperature dependence should be well established. The bucklings of the two lattices studied (square pitches 24 and 27 cm) were found to be less sensitive to temperature than theoretical calculations predict, the temperature coefficient being more than 10 per cent smaller. The buckling changes from 20 to 250 deg C were about -2.4 and -1.8/m 2 , respectively, for the two lattices. During part of the experimental period we had, for some unexplained reason, about 30 per cent excess absorption in the heavy water

Dai bisogni di salute al consumo di risorse sanitarie in provincia di Bergamo: profilo degli indicatori di bisogno, domanda, offerta

Directory of Open Access Journals (Sweden)

A. Zucchi

2003-05-01

Full Text Available

Introduzione: la complessità interpretativa dei dati relativi ad alcuni fenomeni sanitari a livello territoriale impone la necessità di uno strumento semplice di lettura “epidemiologica”; tale lettura si fonda sull’utilizzo di una serie di “indicatori”, fondamenta di un processo dinamico di monitoraggio temporale e spaziale in grado di descrivere sinteticamente fenomeni di per sé complessi, al fine di fornire al decisore un supporto sintetico ma scientificamente solido.

Obiettivi: istituzione di un sistema di monitoraggio sanitario community-based; definizione di indicatori sanitari comparabili tramite un esame critico dei dati esistenti; sviluppo di metodologie per la raccolta e la validazione dei dati; supporto alla creazione di un sistema efficace e affidabile di trasferimento e scambio dei dati e degli indicatori stessi con uso spinto della tecnologia telematica; elaborazione di metodi e di strumenti necessari alla produzione di analisi e relazioni.

Materiali e metodi: gli indicatori analizzati fanno riferimento
all’elenco definito dal decreto ministeriale n. 27 del 12 dicembre 2001 “sistema di garanzie per il monitoraggio dell’assistenza sanitaria”. A questo elenco ne sono stati aggiunti altri, per un totale di 127, divisi in grandi capitoli tematici: assistenza sanitaria, assistenza distrettuale, assistenza ospedaliera, indicatori stato di salute, consumo di risorse sanitarie (cui è stato dato particolare enfasi, indicatori di domanda/accessibilità. Per definire infine un
profilo di sintesi di questi grandi capitoli e delle relative
eterogeneità territoriali si è successivamente applicata la tecnica statistica dello “z-score”.
Risultati: le differenze emerse a livello distrettuale hanno permesso di disegnare una ‘mappa’ degli indicatori sanitari in provincia di Bergamo.

Conclusioni:i risultati di

Influence of deposition temperature on the structural and morphological properties of Be3N2 thin films grown by reactive laser ablation

International Nuclear Information System (INIS)

Chale-Lara, F.; Farias, M.H.; De la Cruz, W.; Zapata-Torres, M.

2010-01-01

Be 3 N 2 thin films have been grown on Si(1 1 1) substrates using the pulsed laser deposition method at different substrate temperatures: room temperature (RT), 200 deg. C, 400 deg. C, 600 deg. C and 700 deg. C. Additionally, two samples were deposited at RT and were annealed after deposition in situ at 600 deg. C and 700 deg. C. In order to obtain the stoichiometry of the samples, they have been characterized in situ by X-ray photoelectron (XPS) and reflection electron energy loss spectroscopy (REELS). The influence of the substrate temperature on the morphological and structural properties of the films was investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that all prepared films presented the Be 3 N 2 stoichiometry. Formation of whiskers with diameters of 100-200 nm appears at the surface of the films prepared with a substrate temperature of 600 deg. C or 700 deg. C. However, the samples grown at RT and annealed at 600 deg. C or 700 deg. C do not show whiskers on the surface. The average root mean square (RMS) roughness and the average grain size of the samples grown with respect the substrate temperature is presented. The films grown with a substrate temperature between the room temperature to 400 deg. C, and the sample annealed in situ at 600 deg. C were amorphous; while the αBe 3 N 2 phase was presented on the samples with a substrate temperature of 600 deg. C, 700 deg. C and that deposited with the substrate at RT and annealed in situ at 700 deg. C.

Corrosion rate of parent and weld materials of F82H and JPCA steels under LBE flow with active oxygen control at 450 and 500 deg. C

International Nuclear Information System (INIS)

Kikuchi, Kenji; Kamata, Kinya; Ono, Mikinori; Kitano, Teruaki; Hayashi, Kenichi; Oigawa, Hiroyuki

2008-01-01

Corrosion behavior of parent and weld materials of F82H and JPCA was studied in the circulating LBE loop under impinging flow. These are candidate materials for Japanese Accelerator Driven System (ADS) beam windows. Maximum temperatures were kept to 450 and 500 deg. C with 100 deg. C constant temperature difference. Main flow velocity was 0.4-0.6 m/s in every case. Oxygen concentration was controlled to 2-4 x 10 -5 mass% although there was one exception. Testing time durations were 500-3000 h. Round bar type specimens were put in the circular tube of the loop. An electron beam weld in the middle of specimens was also studied. Optical microscopy, electron microscopy, X-ray element analyses and X-ray diffraction were used to investigate corrosion in these materials. Consequently corrosion depth and stability of those oxide layers were characterized based on the analyses. For a long-term behavior a linear law is recommended to predict corrosion in the ADS target design

A thermodynamic data base for Tc to calculate equilibrium solubilities at temperatures up to 300 deg C

International Nuclear Information System (INIS)

Puigdomenech, I.; Bruno, J.

1995-04-01

Thermodynamic data has been selected for solids and aqueous species of technetium. Equilibrium constants have been calculated in the temperature range 0 to 300 deg C at a pressure of 1 bar for T r Cdeg pm values for mononuclear hydrolysis reactions. The formation constants for chloro complexes of Tc(V) and Tc(IV), whose existence is well established, have been estimated. The majority of entropy and heat capacity values in the data base have also been estimated, and therefore temperature extrapolations are largely based on estimations. The uncertainties derived from these calculations are described. Using the data base developed in this work, technetium solubilities have been calculated as a function of temperature for different chemical conditions. The implications for the mobility of Tc under nuclear repository conditions are discussed. 70 refs

Tests of the new STIC scintillator ring prototype, the photomultipliers and optic fibers cables of the 40 deg C counters

International Nuclear Information System (INIS)

Silva, Tatiana da

1997-01-01

This paper reports the tests performed on the semicircular prototype of the new scintillator ring with readings obtained by WLS optic fibers. The prototype intends to verify the light collecting and investigate a method for fiber gluing in a circular surface, without the appearing of air bubbles which may restrain the light transmission. Also the optic fiber cables and the photomultipliers used in the 40 deg C counters have been tested in order to verify the electromagnetic energy which may leak from failures in the barrel, aiming the hermeticity enhancement, and also the existence of any damaged cable

Interaction of nitrogen with vacancy defects in N+-implanted ZnO studied using a slow positron beam

International Nuclear Information System (INIS)

Chen, Z.Q.; Maekawa, M.; Kawasuso, A.; Suzuki, R.; Ohdaira, T.

2005-01-01

ZnO crystals were implanted with N + , O + , and Al + , and co-implanted with O + /N + and Al + /N + ions. Positron annihilation measurements indicate introduction of vacancy clusters upon implantation. In the N + -implanted and Al + /N + co-implanted samples, these vacancy clusters are only partially annealed at 800 deg. C, as compared with their entire recovery in the O + - and Al + -implanted samples at 800-900 deg. C, suggesting a strong interaction between nitrogen and vacancy clusters. However, in the O + /N + co-implanted sample, most vacancy clusters disappear at 800 deg. C. Probably oxygen scavenges nitrogen to enhance the annealing of the vacancy clusters. Upon further annealing at 1000-1100 deg. C, nitrogen also forms stable complexes with thermally generated vacancies. These nitrogen-related vacancy complexes need high-temperature annealing at 1200-1250 deg. C to be fully removed

Atlante project. A landscape planning and management; Progetto Atlante. Quadro di riferimento, analisi degli strumenti esistenti, implementazione metodologica e applicazione prototipale

Energy Technology Data Exchange (ETDEWEB)

Baratozzi, L.; Cagnoli, P.; Filippi, N.; Gherardi, L.; Montaletti, V.; Poli, G.; Scarelli, M. [Regione Emilia-Romagna, Assessorato Territorio, Programmazione e Ambiente, Servizio Paesaggio, Parchi e Patrimonio Naturale, Bologna (Italy); Basili, M.; Battista, A.; Colonna, N.; Del Ciello, R.; Forni, A.; Olivetti, I.; Regina, P.; Zarlenga, F. [ENEA, Divisione Caratterizzazione dell' Ambiente e del Territorio, Centro Ricerche della Casaccia, Rome (Italy)

2001-07-01

The Atlante Project applied in Emilia-Romagna region, has the objective in management of transformations in landscape, evaluating the sustainability of choice of programming. [Italian] Il progetto Atlante, si e' posto l'obiettivo di verificare la validita' delle Unita' di Paesaggio, come riferimento per una gestione delle trasformazioni del territorio, che permetta di anticipare la valutazione della sostenibilita' delle scelte della programmazione superando l'attuale prassi di verifica amministrativa a posteriori, che l'esperienza degli ultimi anni ha dimostrato non essere efficace.

Oxidation of nuclear fuel below 400 deg. Consequence on long-term dry storage; L'oxydation du combustible nucleaire au-dessous de 400 deg. Consequences sur l'entreposage a sec de longue duree

Energy Technology Data Exchange (ETDEWEB)

Dehaudt, Ph

2000-07-01

This document reviews the status of the knowledge on the oxidation of fuels below 400 deg C, in all its forms, including fuel rods, by examining the consequences of this reaction on the strength or ruin of the fuel rods during dry storage in air for a hundred years. The data available in the scientific literature, and the data acquired by CEA, are abundant on irradiated powders and pellets, but sparser for irradiated fuel fragments and for rods or sections of fuel rods. A bibliographic review is made to identify the morphological and structural changes, as well as the kinetic laws. An analysis and a summary is made with a concern to evaluate the risks of rod ruin by oxidation. The final section, in a few pages, addresses the essential lessons from this study. It presents: first, a summary of the main results of this review and its analysis, recommendations and remedies for storage; proposed research guidelines as well as precise topics, in order to fill out our knowledge and, even better, to identify the acceptable limits for storage. (author)

Oxidation Behavior of AlN/h-BN Nano Composites at High Temperature

International Nuclear Information System (INIS)

Jin Haiyun; Huang Yinmao; Feng Dawei; He Bo; Yang Jianfeng

2011-01-01

Both AlN/ nano h-BN composites and AlN/ micro h-BN composites were fabricated. The high temperature oxidation behaviors were investigated at 1000deg. C and 1300deg. C using a cycle-oxidation method. The results showed that there were little changes of both nano composites and monolithic AlN ceramic at temperature of 1000deg. C. And at 1300deg. C, the oxidation dynamics curve of composites could be divided into two courses: a slowly weight increase and a rapid weight decrease, but the oxidation behavior of nano composites was better than micro composites. It was due to that the uniform distribution of oxidation production (Al 18 B 4 O 33 ) surround the AlN grains in nano composites and the oxidation proceeding was retarded. The XRD analysis and SEM observations showed that there was no BN remained in the composites surface after 1300deg. C oxidation and the micropores remain due to the vaporizing of B 2 O 3 oxidized by BN.

Growth parameter investigation of Al0.25Ga0.75N/GaN/AlN heterostructures with Hall effect measurements

International Nuclear Information System (INIS)

Lisesivdin, S B; Demirezen, S; Kasap, M; Ozcelik, S; Caliskan, M D; Ozbay, E; Yildiz, A

2008-01-01

Hall effect measurements on unintentionally doped Al 0.25 Ga 0.75 N/GaN/AlN heterostructures grown by metal organic chemical vapor deposition (MOCVD) were carried out as a function of temperature (20–300 K) and magnetic field (0–1.4 T). Magnetic-field-dependent Hall data are analyzed using the quantitative mobility spectrum analysis (QMSA) technique. The QMSA technique successfully separated electrons in the 2D electron gas (2DEG) at the Al 0.25 Ga 0.75 N/GaN interface from other 2D and 3D conduction mechanisms of the samples. 2DEG mobilities, carrier densities and conductivities of the investigated samples are compared at room temperature and low temperature (20 K). For a detailed investigation of the 2DEG-related growth parameters, the scattering analyses of the extracted 2DEG were carried out for all of the samples. Using the results of the scattering analyses, the relation between the growth and scattering parameters was investigated. Increments in the interface roughness (IFR) are reported with the increased GaN buffer growth temperatures. In addition, a linear relation between the deformation potential and interface roughness (IFR) scattering is pointed out for the investigated samples, which may lead to a better understanding of the mechanism of IFR scattering

Materials for higher steam temperatures (up to 600 deg C) in biomass and waste fired plant. A review of present knowledge; Material foer hoegre aangtemperaturer (upp till 600 grader C) i bio- och avfallseldade anlaeggningar

Energy Technology Data Exchange (ETDEWEB)

Staalenheim, Annika; Henderson, Pamela

2011-02-15

A goal for the Swedish power industry is to build a demonstration biomass-fired plant with 600 deg C steam data in 2015. Vaermeforsk also has a goal to identify materials that can be used in such a plant. This project involves a survey of present knowledge and published articles concerning materials that are suitable for use in biomass and wastefired plants with steam data up to 600 deg C. The information has been gathered from plants presently in operation, and from field tests previously performed with probes. Plants firing only household waste are excluded. The components considered are waterwalls/furnace walls (affected because of higher steam pressures) and superheaters. Fireside corrosion and steam-side oxidation are dealt with. Candidate materials (or coatings) are suggested and areas for further research have been identified. The purpose of this project is to give state-of-the-art information on what materials could be used in biomass and waste-fired plant to reach a maximum steam temperature of 600 deg C. This report is aimed at suppliers of boilers and materials, energy utility companies and others involved in building new plant with higher steam data. In accordance with the goals of this project: - Materials suitable for use at higher steam temperatures (up to 600 deg C steam) in wood-based biomass and waste-fired plant have been identified. Austenitic stainless steels HR3C, TP 347 HFG and AC66 all have adequate strength, steam-side oxidation and fireside corrosion resistance for use as superheaters. AC66 and HR3C have better steam-side oxidation resistance than TP 347 HFG , but TP 347 HFG has better fireside corrosion resistance. It is recommended that TP 347 HFG be shot-peened on the inside to improve the oxidation resistance if in service with steam temperatures above 580 deg C. - Furnace walls coated with Ni-based alloys or a mixture of Ni- alloy and ceramic show good corrosion resistance at lower temperatures and should be evaluated at higher

III-Nitrides growth and AlGaN/GaN heterostructures on ferroelectric materials

International Nuclear Information System (INIS)

Lee, Kyoung-Keun; Namkoong, Gon; Madison, Shannon M.; Ralph, Stephen E.; Doolittle, W. Alan; Losurdo, Maria; Bruno, Giovanni; Cho, Hyung Koun

2007-01-01

The growth of III-nitrides on the ferroelectric materials lithium niobate (LN) and lithium tantalate (LT) via molecular beam epitaxy (MBE) using rf plasma source has been investigated. We have found that gallium nitride (GaN) epitaxial layers have a crystalline relationship with lithium niobate (tantalate) as follows: (0 0 0 1) GaN || (0 0 0 1) LN (LT) with [10-10] GaN || [11-20] LN (LT). The surface stability of LN and LT substrates has been monitored by in situ spectroscopic ellipsometry in the vacuum chamber. Three different temperature zones have been discerned; surface degas and loss of OH group (100-350 deg. C); surface segregation/accumulation of Li and O-species (400-700 deg. C); surface evaporation of O-species and Li desorption (over 750 deg. C). However, LT shows only surface degassing in the range of 100-800 deg. C. Therefore, congruent LN substrates were chemically unstable at the growth temperature of 550-650 deg. C, and therefore developed an additional phase of Li-deficient lithium niobate (LiNb 3 O 8 ) along with lithium niobate (LiNbO 3 ), confirmed by X-ray diffraction. On the other hand, LT showed better chemical stability at these temperatures, with no additional phase development. The structural quality of GaN epitaxial layers has shown slight improvement on LT substrates over LN substrates, according to X-ray diffraction. Herein, we demonstrate AlGaN/GaN heterostructure devices on ferroelectric materials that will allow future development of multifunctional electrical and optical applications

III-Nitrides growth and AlGaN/GaN heterostructures on ferroelectric materials

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyoung-Keun [Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA 30332 (United States); Namkoong, Gon [Old Dominion University, Department of Electrical and Computer Engineering, Norfolk, VA 23529 (United States); Madison, Shannon M. [Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA 30332 (United States); Ralph, Stephen E. [Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA 30332 (United States); Doolittle, W. Alan [Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA 30332 (United States)]. E-mail: alan.doolittle@ece.gatech.edu; Losurdo, Maria [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR, Department of Chemistry, University of Bari, via Orabona, 4 70126 Bari (Italy); Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR, Department of Chemistry, University of Bari, via Orabona, 4 70126 Bari (Italy); Cho, Hyung Koun [Department of Materials Science and Engineering, Sung Kyun Kwan University, Suwon 440-746 (Korea, Republic of)

2007-06-15

The growth of III-nitrides on the ferroelectric materials lithium niobate (LN) and lithium tantalate (LT) via molecular beam epitaxy (MBE) using rf plasma source has been investigated. We have found that gallium nitride (GaN) epitaxial layers have a crystalline relationship with lithium niobate (tantalate) as follows: (0 0 0 1) GaN || (0 0 0 1) LN (LT) with [10-10] GaN || [11-20] LN (LT). The surface stability of LN and LT substrates has been monitored by in situ spectroscopic ellipsometry in the vacuum chamber. Three different temperature zones have been discerned; surface degas and loss of OH group (100-350 deg. C); surface segregation/accumulation of Li and O-species (400-700 deg. C); surface evaporation of O-species and Li desorption (over 750 deg. C). However, LT shows only surface degassing in the range of 100-800 deg. C. Therefore, congruent LN substrates were chemically unstable at the growth temperature of 550-650 deg. C, and therefore developed an additional phase of Li-deficient lithium niobate (LiNb{sub 3}O{sub 8}) along with lithium niobate (LiNbO{sub 3}), confirmed by X-ray diffraction. On the other hand, LT showed better chemical stability at these temperatures, with no additional phase development. The structural quality of GaN epitaxial layers has shown slight improvement on LT substrates over LN substrates, according to X-ray diffraction. Herein, we demonstrate AlGaN/GaN heterostructure devices on ferroelectric materials that will allow future development of multifunctional electrical and optical applications.

Buckling measurements up to 250 deg C on lattices of Agesta clusters and on D{sub 2}O alone in the pressurized exponential assembly TZ

Energy Technology Data Exchange (ETDEWEB)

Persson, R; Andersson, A J.W.; Wikdahl, C E

1966-11-15

Buckling determinations by means of flux mapping were performed in TZ up to 250 deg C on two lattices of Aagesta fuel assemblies in D{sub 2}O and on D{sub 2}O alone. Most of the flux measurements were made with fission counters in pressure thimbles. The perturbations caused by the thimbles were studied experimentally in various ways and compared with two group diffusion-theory calculations. In one of the lattices the effectiveness of a control rod (AglnCd) was also investigated. The results of the diffusion length experiments indicated some systematic error of the order of 0.15 - 0.10/m{sup 2} in the bucklings measured, though the temperature dependence should be well established. The bucklings of the two lattices studied (square pitches 24 and 27 cm) were found to be less sensitive to temperature than theoretical calculations predict, the temperature coefficient being more than 10 per cent smaller. The buckling changes from 20 to 250 deg C were about -2.4 and -1.8/m{sup 2}, respectively, for the two lattices. During part of the experimental period we had, for some unexplained reason, about 30 per cent excess absorption in the heavy water.

The role of particle size on the electrochemical properties at 25 and at 55 deg. C of the LiCr0.2Ni0.4Mn1.4O4 spinel as 5 V-cathode materials for lithium-ion batteries

International Nuclear Information System (INIS)

Aklalouch, Mohamed; Rojas, Rosa M.; Rojo, Jose Maria; Saadoune, Ismael; Amarilla, Jose Manuel

2009-01-01

The role of the particle size on the electrochemical properties at 25 and at 55 deg. C of the LiCr 0.2 Ni 0.4 Mn 1.4 O 4 spinel synthesized by combustion method has been determined. Samples with different particle size were obtained by heating the raw spinel from 700 to 1100 deg. C, for 1 h in air. X-ray diffraction patterns revealed that all the prepared materials are single-phase spinels. The main effect of the thermal treatment is the remarkable increase of the particles size from ∼60 to ∼3000 nm as determined by transmission electron microscopy. The electrochemical properties were determined at high discharge currents (1C rate) in two-electrode Li-cells. At 25 and at 55 deg. C, in spite of the great differences in particle size, the discharge capacity drained by all samples is similar (Q dch ∼ 135 mAh g -1 ). Instead, the cycling performances strongly change with the particle size. The spinels with Φ > 500 nm show better cycling stability at 25 and at 55 deg. C than those with Φ -1 ), and remarkable cycling performances (capacity retention after 250 cycles >96%) are very attractive materials as 5V-cathodes for high-energy Li-ion batteries.

Determination of the diffusion coefficients of iron and chromium in Pb17Li at 500 deg C

International Nuclear Information System (INIS)

Simon, N.; Flament, T.; Terlain, A.

1992-01-01

The diffusion of the dissolved metallic species in a liquid metal towards the boundary layer is one of the elementary steps of the overall mass transfer process induced by thermal gradient. This phenomenon is very probably the limiting step in the mass transfer of martensitic Fe-Cr steels in the presence of Pb17Li liquid eutectic alloy. For estimating diffusion flux, the diffusion coefficients of iron and chromium in Pb17Li are needed but are not known. Consequently these data have been determined in CEA laboratory by measuring metal loss of cylindrical specimens after rotation at 500 deg C in Pb17Li for several hours and applying the first Fick diffusion law in the boundary layer whose the thickness has been previously determined by EISENBERG. After a description of the experimental device, the results are presented and discussed

I capricci del caso Introduzione alla statistica, al calcolo delle probabilità e alla teoria degli errori

CERN Document Server

Piazza, Roberto

2009-01-01

I metodi probabilistici e statistici giocano un ruolo di primo piano sia nella scienza teorica e sperimentale che nelle applicazioni ingegneristiche, costituendo pertanto un elemento essenziale del bagaglio culturale che uno studente deve acquisire fin dai primi anni di apprendimento universitario. Questo libro, che nasce dall’esperienza didattica accumulata dall’autore nell’insegnamento dei metodi sperimentali, si propone di fornire un’introduzione al calcolo delle probabilità e alla teoria degli errori facendo uso di uno stile di presentazione volutamente informale e traendo spunto da concrete applicazioni sperimentali, spesso attraverso esempi di notevole importanza storica. Così, per esempio, argomenti quali il moto browniano, la diffusione di luce, il decadimento radioattivo, la fisiologia della visione, le statistiche quantistiche e di fotorivelazione, vengono utilizzati per delucidare concetti chiave dell’analisi statistica e probabilistica. Un'enfasi particolare è posta sull’origine e l...

Early phyllosilicates formed by alteration of R7T7 glass in water at 250 deg C

International Nuclear Information System (INIS)

Vernaz, E.; Dussossoy, J.L.; Caurel, J.; Crovisier, J.L.

1991-01-01

T7T7 glass samples have been altered during periods of one and seven days at 250 deg C in distilled water. Ultramicrotomic thin sections were performed in the outermost part of the glass for a study under analytical transmission electron microscope. After one day the alteration layer is about 5 μm thick. It is made up of sheeted silicated particles, tentatively identified as septechlorite (7 A intervals) mixed with an intercrystalline amorphous matrix of different composition. After seven days the alteration layer is about 11 μm thick. It is made up of sheeted silicated particles of smectite type (10 A intervals). No 7 A particles were found in the seven days sample. This study illustrates the capacity of poorly crystalline phyllosilicates to adapt to the chemical changes in solution. 15 refs., 4 tabs., 2 plates

Class H cement hydration at 180 deg. C and high pressure in the presence of added silica

International Nuclear Information System (INIS)

Jupe, Andrew C.; Wilkinson, Angus P.; Luke, Karen; Funkhouser, Gary P.

2008-01-01

Under deep oil-well conditions of elevated temperature and pressure, crystalline calcium silicate hydrates are formed during Portland cement hydration. The use of silica rich mineral additives leads to the formation of crystalline hydrates with better mechanical properties than those formed without the additive. The effects of silica flour, silica fume (amorphous silica), and a natural zeolite mixture on the hydration of Class H cement slurries at 180 deg. C under externally applied pressures of 7 and 52 MPa are examined in real time using in-situ synchrotron X-ray diffraction. For some compositions examined, but not all, pressure was found to have a large effect on the kinetics of crystalline hydrate formation. The use of silica fume delayed both C 3 S hydration and the formation of crystalline silicate hydrates compared to what was seen with other silica sources

Influence of deposition temperature on the structural and morphological properties of Be{sub 3}N{sub 2} thin films grown by reactive laser ablation

Energy Technology Data Exchange (ETDEWEB)

Chale-Lara, F., E-mail: fabio_chale@yahoo.com.mx [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2681, Ensenada, Baja California, C.P. 22860 (Mexico); Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, Apartado Postal 14, Ensenada CP 22860, Baja California (Mexico); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Unidad Altamira, Km. 14.5 Carretera Tampico-Puerto Industrial, Altamira, Tamaulipas (Mexico); Farias, M.H.; De la Cruz, W. [Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, Apartado Postal 14, Ensenada CP 22860, Baja California (Mexico); Zapata-Torres, M. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, Del. Miguel Hidalgo, Mexico D.F. (Mexico)

2010-10-01

Be{sub 3}N{sub 2} thin films have been grown on Si(1 1 1) substrates using the pulsed laser deposition method at different substrate temperatures: room temperature (RT), 200 deg. C, 400 deg. C, 600 deg. C and 700 deg. C. Additionally, two samples were deposited at RT and were annealed after deposition in situ at 600 deg. C and 700 deg. C. In order to obtain the stoichiometry of the samples, they have been characterized in situ by X-ray photoelectron (XPS) and reflection electron energy loss spectroscopy (REELS). The influence of the substrate temperature on the morphological and structural properties of the films was investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that all prepared films presented the Be{sub 3}N{sub 2} stoichiometry. Formation of whiskers with diameters of 100-200 nm appears at the surface of the films prepared with a substrate temperature of 600 deg. C or 700 deg. C. However, the samples grown at RT and annealed at 600 deg. C or 700 deg. C do not show whiskers on the surface. The average root mean square (RMS) roughness and the average grain size of the samples grown with respect the substrate temperature is presented. The films grown with a substrate temperature between the room temperature to 400 deg. C, and the sample annealed in situ at 600 deg. C were amorphous; while the {alpha}Be{sub 3}N{sub 2} phase was presented on the samples with a substrate temperature of 600 deg. C, 700 deg. C and that deposited with the substrate at RT and annealed in situ at 700 deg. C.

Transonic Aerodynamic Loading Characteristics of a Wing-Body-Tail Combination Having a 52.5 deg. Sweptback Wing of Aspect Ratio 3 With Conical Wing Camber and Body Indentation for a Design Mach Number of Square Root of 2

Science.gov (United States)

Cassetti, Marlowe D.; Re, Richard J.; Igoe, William B.

1961-01-01

An investigation has been made of the effects of conical wing camber and body indentation according to the supersonic area rule on the aerodynamic wing loading characteristics of a wing-body-tail configuration at transonic speeds. The wing aspect ratio was 3, taper ratio was 0.1, and quarter-chord-line sweepback was 52.5 deg. with 3-percent-thick airfoil sections. The tests were conducted in the Langley 16-foot transonic tunnel at Mach numbers from 0.80 to 1.05 and at angles of attack from 0 deg. to 14 deg., with Reynolds numbers based on mean aerodynamic chord varying from 7 x 10(exp 6) to 8 x 10(exp 6). Conical camber delayed wing-tip stall and reduced the severity of the accompanying longitudinal instability but did not appreciably affect the spanwise load distribution at angles of attack below tip stall. Body indentation reduced the transonic chordwise center-of-pressure travel from about 8 percent to 5 percent of the mean aerodynamic chord.

Study of the chemical interaction between the beryllium powders of different particles size and the air in the temperature range 500-1000degC form the viewpoint of ITER safety

Energy Technology Data Exchange (ETDEWEB)

Davydov, D.A. [State Scientific Center of Russian Federation, Moscow (Russian Federation); Konovalov, Y.V.; Gorokhov, V.A.; Levin, V.B.; Chekhlatov, G.M.; Khomutov, A.M.

1998-01-01

Under an effect of some factors characteristic for the ITER- operating condition a dense beryllium facing plasma can transit into various forms, changing its structural states. As a result of the bombardment of beryllium plasma facing components by ion fluxes, the production of a dust including the particles from a few micrometers to a few millimeters in size is possible. The specific features in the behaviour of various beryllium forms under emergency conditions are of an essential interest from the viewpoint of ITER safety. Some grades of powders of different average particles size (14-31 micron) have been produced in a given study, and their chemical interaction at high temperatures with air (500-1100degC), test duration effects simulating the emergency situation at ITER in the first approximation have been studied. The temperature dependence of beryllium powders (different particles size after disc abrased) interaction with air in the temperature range 500-1000degC at the exposure of 5 hours long for each temperature and kinetic dependence of interaction of these powders with air at 800degC for the exposure from half an hour to 7 hours long were studied. An analysis of granulometric weight fraction in the metallic and oxidized beryllium powders with different particles size has been done by the photosedimentational technique with the instrument `Analysette-20`. Construction of a mathematical model for the chemical interaction of beryllium powders with air at high temperatures have been carried out. (author)

The Sloan Digital Sky Survey Stripe 82 Imaging Data: Depth-Optimized Co-adds Over 300 deg$^2$ in Five Filters

Energy Technology Data Exchange (ETDEWEB)

Jiang, Linhua; Fan, Xiaohui; Bian, Fuyan; McGreer, Ian D.; Strauss, Michael A.; Annis, James; Buck, Zoë; Green, Richard; Hodge, Jacqueline A.; Myers, Adam D.; Rafiee, Alireza; Richards, Gordon

2014-06-25

We present and release co-added images of the Sloan Digital Sky Survey (SDSS) Stripe 82. Stripe 82 covers an area of ~300 deg(2) on the celestial equator, and has been repeatedly scanned 70-90 times in the ugriz bands by the SDSS imaging survey. By making use of all available data in the SDSS archive, our co-added images are optimized for depth. Input single-epoch frames were properly processed and weighted based on seeing, sky transparency, and background noise before co-addition. The resultant products are co-added science images and their associated weight images that record relative weights at individual pixels. The depths of the co-adds, measured as the 5σ detection limits of the aperture (3.''2 diameter) magnitudes for point sources, are roughly 23.9, 25.1, 24.6, 24.1, and 22.8 AB magnitudes in the five bands, respectively. They are 1.9-2.2 mag deeper than the best SDSS single-epoch data. The co-added images have good image quality, with an average point-spread function FWHM of ~1'' in the r, i, and z bands. We also release object catalogs that were made with SExtractor. These co-added products have many potential uses for studies of galaxies, quasars, and Galactic structure. We further present and release near-IR J-band images that cover ~90 deg(2) of Stripe 82. These images were obtained using the NEWFIRM camera on the NOAO 4 m Mayall telescope, and have a depth of about 20.0-20.5 Vega magnitudes (also 5σ detection limits for point sources).

Creep testing and creep loading experiments on friction stir welds in copper at 75 deg C

International Nuclear Information System (INIS)

Andersson, Henrik C.M.; Seitisleam, Facredin; Sandstroem, Rolf

2007-08-01

Specimens cut from friction stir welds in copper canisters for nuclear waste have been used for creep experiments at 75 deg C. The specimens were taken from a cross-weld position as well as heat affected zone and weld metal. The parent metal specimens exhibited longer creep lives than the weld specimens by a factor of three in time. They in turn were longer than those for the crossweld and HAZ specimens by an order of magnitude. The creep exponent was in the interval 50 to 69 implying that the material was well inside the power-law breakdown regime. The ductility properties expressed as reduction in area were not significantly different and all the rupture specimens demonstrated values exceeding 80%. Experiments were also carried out on the loading procedure of a creep test. Similar parent metal specimens and test conditions were used and the results show that the loading method has a large influence on the strain response of the specimen

Wide-bandwidth electron bolometric mixers - A 2DEG prototype and potential for low-noise THz receivers

Science.gov (United States)

Yang, Jian-Xun; Agahi, Farid; Dai, Dong; Musante, Charles F.; Grammer, Wes; Lau, Kei M.; Yngvesson, K. S.

1993-01-01

This paper presents a new type of electron bolometric ('hot electron') mixer. We have demonstrated a 3 order-of-magnitude improvement in the bandwidth compared with previously known types of electron bolometric mixers, by using the two-dimensional electron gas (2DEG) medium at the heterointerface between AlGaAs and GaAs. We have tested both in-house MOCVD-grown material and MBE material, with similar results. The conversion loss (Lc) at 94 GHz is presently 18 dB for a mixer operating at 20 K, and calculations indicate that Lc can be decreased to about 10 dB in future devices. Calculated and measured curves of Lc versus P(LO), and I(DC), respectively, agree well. We argue that there are several different configurations of electron bolometric mixers, which will all show wide bandwidth, and that these devices are likely to become important as low-noise THz receivers in the future.

Calculations of the flow past bluff bodies, including tilt-rotor wing sections at alpha = 90 deg

Science.gov (United States)

Raghavan, V.; Mccroskey, W. J.; Baeder, J. D.; Van Dalsem, W. R.

1990-01-01

An attempt was made to model in two dimensions the effects of rotor downwash on the wing of the tilt-rotor aircraft and to compute the drag force on airfoils at - 90 deg angle of attack, using a well-established Navier-Stokes code. However, neither laminar nor turbulent calculations agreed well with drag and base-pressure measurements at high Reynolds numbers. Therefore, further efforts were concentrated on bluff-body flows past various shapes at low Reynolds numbers, where a strong vortex shedding is observed. Good results were obtained for a circular cylinder, but the calculated drag of a slender ellipse at right angles to the freestream was significantly higher than experimental values reported in the literature for flat plates. Similar anomalous results were obtained on the tilt-rotor airfoils, although the qualitative effects of flap deflection agreed with the wind tunnel data. The ensemble of results suggest that there may be fundamental differences in the vortical wakes of circular cylinders and noncircular bluff bodies.

Creep testing and creep loading experiments on friction stir welds in copper at 75 deg C

Energy Technology Data Exchange (ETDEWEB)

Andersson, Henrik C.M.; Seitisleam, Facredin; Sandstroem, Rolf [Corrosion an d Metals Research Institute, Stockholm (Sweden)

2007-08-15

Specimens cut from friction stir welds in copper canisters for nuclear waste have been used for creep experiments at 75 deg C. The specimens were taken from a cross-weld position as well as heat affected zone and weld metal. The parent metal specimens exhibited longer creep lives than the weld specimens by a factor of three in time. They in turn were longer than those for the crossweld and HAZ specimens by an order of magnitude. The creep exponent was in the interval 50 to 69 implying that the material was well inside the power-law breakdown regime. The ductility properties expressed as reduction in area were not significantly different and all the rupture specimens demonstrated values exceeding 80%. Experiments were also carried out on the loading procedure of a creep test. Similar parent metal specimens and test conditions were used and the results show that the loading method has a large influence on the strain response of the specimen.

Effect of chloride and sulphate ions on the electrochemical corrosion behavior of alloy 800NG in PWR secondary water environment at 250 deg C

International Nuclear Information System (INIS)

Mansur, Fabio A.; Schvartzman, Monica Maria de A.M.; Quinan, Marco A.D.; Soares, Antonio E.G.; Nogueira, Pedro Henrique B.O.

2013-01-01

Alloy 800NG (nuclear grade) is used in nuclear steam generators (SG) as the tubing material for pressurized water reactors (PWRs) because of its high corrosion resistance. The corrosion resistance is due to the protective character of the oxide film formed on the tube surface by contact with the high temperature pressurized water. Nevertheless, corrosion has been the major cause of tube failures in nuclear SGs. The existing experience of different nuclear power plants shows that the water chemistry has an important role in maintaining the integrity of the protective oxide films. Many of such problems have been attributed to secondary side water chemistry conditions and excursions, many of which have been resulted from condenser cooling water ingress. Alloy 800 is known to undergo passivity breakdown and pitting in the presence of chloride ions under oxidative water conditions. In this work the effect of chloride and sulphate ions at various concentrations on the corrosion behavior of Alloy 800 tube at 250 deg C was investigated using the potentiodynamic anodic polarization technique. An active-passive transition occurred at 250 deg C in all studied conditions and the oxide film grown on surface showed greater porosity and lower resistance to localised corrosion in all studied conditions. (author)

Critérios de correção da linguagem: o uso do Libro dell’Abate Isaac di Siria no Vocabolario degli Accademici della Crusca

Directory of Open Access Journals (Sweden)

Cynthia Vilaça

2015-12-01

Full Text Available In this paper, we present an analysis of the use of the ascetic treatise Libro dell’Abate Isaac of Syria by academicians of the Crusca as a source of accreditations for the preparation of the Vocabolario degli Accademici della Crusca, noted Italian lexicographical work, in light of the criteria used for the construction of the educated norm discussed by Bechara (2000

Interactions in Zircaloy/UO2 fuel rod bundles with Inconel spacers at temperatures above 1200deg C (posttest results of severe fuel damage experiments CORA-2 and CORA-3)

International Nuclear Information System (INIS)

Hagen, S.; Hofmann, P.; Schanz, G.; Sepold, L.

1990-09-01

In the CORA experiments test bundles of usually 16 electrically heated fuel rod simulators and nine unheated rods are subjected to temperature transients of a slow heatup rate in a steam environment. Thus, an accident sequence is simulated, which may develop from a small-break loss-of-coolant accident of an LWR. An aim of CORA-2, as a first test of its kind, was also to gain experience in the test conduct and posttest handling of UO 2 specimens. CORA-3 was performed as a high-temperature test. The transient phases of CORA-2 and CORA-3 were initiated with a temperature ramp rate of 1 K/s. The temperature escalation due to the exothermal zircaloy(Zry)-steam reaction started at about 1000deg C, leading the bundles to maximum temperatures of 2000deg C and 2400deg C for tests CORA-2 and CORA-3, respectively. The test bundles resulted in severe oxidation and partial melting of the cladding, fuel dissolution by Zry/UO 2 interaction, complete Inconel spacer destruction, and relocation of melts and fragments to lower elevations in the bundle, where extended blockages have formed. In both tests the fuel rod destruction set in together with the formation of initial melts from the Inconel/Zry interaction. The lower Zry spacer acted as a catcher for relocated material. In test CORA-2 the UO 2 pellets partially disintegrated into fine particles. This powdering occurred during cooldown. There was no physical disintegration of fuel in test CORA-3. (orig./MM) [de

Synchrotron X-ray topography studies of twinning and the phase transition at 145deg C in LaGaO sub 3 single crystals

Energy Technology Data Exchange (ETDEWEB)

Yao, G.D.; Dudley, M. (Dept. of Materials Science and Engineering, State Univ. of New York, Stony Brook, NY (USA)); Wang, Y.; Liu, X.; Liebermann, R.C. (Dept. of Earth and Space Sciences, State Univ. of New York, Stony Brook, NY (USA))

1991-02-01

An investigation of (i) twinning in the room temperature orthorhombic phase, (ii) the orthorhombic-to-rhombohedral phase transformation occurring at 145deg C and (iii) twinning in the high temperature rhombohedral phase, all occurring in lanthanum gallate single crystals has been undertaken using white-beam synchrotron X-ray topography (WBSXRT). At room temperature, WBSXRT results obtained from the (110){sub orth} surface, orthorhombic crystals indicated the presence of ''mirror'' twinning on (1anti 12){sub orth}, (1anti 1anti 2){sub orth}, (anti 110){sub orth} and (112){sub orth} planes. Differential thermal analysis confirmed the existence of a first-order phase transformation at 145deg C. WBSXRT observations of the associated structural change (orthorhombic to rhombohedral) correlated well with the results of temperature-dependent powder diffraction results which are presented in the companion paper. WBSXRT also revealed the detailed spatial characteristics of the transition on the microstructural scale, as well as the nature of twinning in the rhombohedral phase, with the latter occurring on (110){sub rhomb} planes. In all three cases, results were consistent with the transmission electron microscopy results presented in the companion paper. The influence of both the twinning and the phase transition on the potential use of LaGaO{sub 3} single crystals as substrates for high Tc superconductor epilayers is discussed. (orig.).

Temperature dependence of InN film deposition by an RF plasma-assisted reactive ion beam sputtering deposition technique

International Nuclear Information System (INIS)

Shinoda, Hiroyuki; Mutsukura, Nobuki

2005-01-01

Indium nitride (InN) films were deposited on Si(100) substrates using a radiofrequency (RF) plasma-assisted reactive ion beam sputtering deposition technique at various substrate temperatures. The X-ray diffraction patterns of the InN films suggest that the InN films deposited at substrate temperatures up to 370 deg C were cubic crystalline InN; and at 500 deg C, the InN film was hexagonal crystalline InN. In a scanning electron microscope image of the InN film surface, facets of cubic single-crystalline InN grains were clearly observed on the InN film deposited at 370 deg C. The inclusion of metallic indium appeared on the InN film deposited at 500 deg C

Enhancement of tributyltin degradation under natural light by N-doped TiO2 photocatalyst

International Nuclear Information System (INIS)

Bangkedphol, S.; Keenan, H.E.; Davidson, C.M.; Sakultantimetha, A.; Sirisaksoontorn, W.; Songsasen, A.

2010-01-01

Photo-degradation of tributyltin (TBT) has been enhanced by TiO 2 nanoparticles doped with nitrogen (N-doped TiO 2 ). The N-doped catalyst was prepared by a sol-gel reaction of titanium (IV) tetraisopropoxide with 25% ammonia solution and calcined at various temperatures from 300 to 600 deg. C. X-ray diffraction results showed that N-doped TiO 2 remained amorphous at 300 deg. C. At 400 deg. C the anatase phase occurred then transformed to the rutile phase at 600 deg. C. The crystallite size calculated from Scherrer's equation was in the range of 16-51 nm which depended on the calcination temperature. N-doped TiO 2 calcined at 400 deg. C which contained 0.054% nitrogen, demonstrated the highest photocatalytic degradation of TBT at 28% in 3 h under natural light when compared with undoped TiO 2 and commercial photocatalyst, P25-TiO 2 which gave 14.8 and 18% conversion, respectively.

Gamma ray production cross sections for the interactions of 14.9 MeV neutrons with C, Al, V, Fe and Nb at 90 deg

International Nuclear Information System (INIS)

Zhou Hongyu; Tang Lin; Yan Yiming

1986-11-01

Discrete γ-ray spectra and production cross sections for the interactions of 14.9 MeV neutrons with C, Al, V, Fe and Nb targets have been measured at 90 deg. using a 110.7cm 3 Ge(Li) detector. A single γ-ray peak was measured for C. For Al 34 γ lines, for Fe 41 γ lines, for V 61 γ lines and for Nb 79 γ lines were measured

Study of the solubility of yttrium, praseodymium, neodymium, and gadolinium sulfates in the presence of sodium and potassium in sulfuric-phosphoric acid solutions at 20 deg C

International Nuclear Information System (INIS)

Lokshin, Eh.P.; Tareeva, O.A.; Kashulina, T.G.

2007-01-01

The solubility of yttrium, praseodymium, neodymium, and gadolinium sulfates in the presence of sodium and potassium ions and the composition of solid phases were studied at 20 deg C in relation to the concentration of acids in sulfuric acid, phosphoric acid, and sulfuric-phosphoric acid solutions containing up to 36 wt % H 2 SO 4 and 33.12 g 1 -1 H 3 PO 4 . The formation of double sulfates of praseodymium and neodymium with sodium and potassium ions, as well as of gadolinium sulfate with sodium ions of the composition 1 : 1 was revealed. In water at 20 deg C, the solubility products of PrNa(SO 4 ) 2 ·H 2 O, NdNa(SO 4 ) 2 ·H 2 O, GdNa(SO 4 ) 2 ·H 2 O, PrK(SO 4 ) 2 ·H 2 O, and NdK(SO 4 ) 2 ·H 2 O are found to be 7.28x10 -8 , 7.84x10 -8 , 3.09x10 -6 , 3.02x10 -6 , and 1.70x10 -6 , respectively [ru

High breakdown voltage in AlGaN/GaN HEMTs using AlGaN/GaN/AlGaN quantum-well electron-blocking layers.

Science.gov (United States)

Lee, Ya-Ju; Yao, Yung-Chi; Huang, Chun-Ying; Lin, Tai-Yuan; Cheng, Li-Lien; Liu, Ching-Yun; Wang, Mei-Tan; Hwang, Jung-Min

2014-01-01

In this paper, we numerically study an enhancement of breakdown voltage in AlGaN/GaN high-electron-mobility transistors (HEMTs) by using the AlGaN/GaN/AlGaN quantum-well (QW) electron-blocking layer (EBL) structure. This concept is based on the superior confinement of two-dimensional electron gases (2-DEGs) provided by the QW EBL, resulting in a significant improvement of breakdown voltage and a remarkable suppression of spilling electrons. The electron mobility of 2-DEG is hence enhanced as well. The dependence of thickness and composition of QW EBL on the device breakdown is also evaluated and discussed.

Structural characterization of Mn implanted AlInN

Energy Technology Data Exchange (ETDEWEB)

Majid, Abdul; Ali, Akbar [Advance Materials Physics Laboratory, Quaid-i-Azam University, Islamabad (Pakistan); Zhu, J J; Wang, Y T [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083 (China)], E-mail: abdulmajid40@yahoo.com, E-mail: akbar@qau.edu.pk

2008-06-07

AlInN/GaN thin films were implanted with Mn ions and subsequently annealed isochronically at 750 and 850 deg. C. X-ray diffraction and Rutherford backscattering spectroscopy (RBS) techniques were employed to study the microstructural properties of the implanted/annealed samples. The effect of annealing on implantation-induced strain in thin films has been studied in detail. The strain was found to increase with dose until it reached a saturation value and after that it started decreasing with a further increase in the dose. RBS measurements indicated the atomic diffusion of In, Al, Ga and Mn in implanted samples. The in- and out-diffusion of atoms has been observed after annealing at 750 deg. C and 850 deg. C, respectively. Strong decomposition of the samples took place when annealed at 850 deg. C.

Structural characterization of Mn implanted AlInN

International Nuclear Information System (INIS)

Majid, Abdul; Ali, Akbar; Zhu, J J; Wang, Y T

2008-01-01

AlInN/GaN thin films were implanted with Mn ions and subsequently annealed isochronically at 750 and 850 deg. C. X-ray diffraction and Rutherford backscattering spectroscopy (RBS) techniques were employed to study the microstructural properties of the implanted/annealed samples. The effect of annealing on implantation-induced strain in thin films has been studied in detail. The strain was found to increase with dose until it reached a saturation value and after that it started decreasing with a further increase in the dose. RBS measurements indicated the atomic diffusion of In, Al, Ga and Mn in implanted samples. The in- and out-diffusion of atoms has been observed after annealing at 750 deg. C and 850 deg. C, respectively. Strong decomposition of the samples took place when annealed at 850 deg. C

MeB/sub 5/O/sub 8/(Me-Li, Na, K, NH/sub 4/)-H/sub 2/NCONHCOCH/sub 3/-H/sub 2/O system at 25 deg C

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Fedorov, Yu A; Molodkin, A K; Tsekhanskij, R S

1986-06-01

Using the methods of isothermal solubility, densi- and refractometry, systems MB/sub 5/O/sub 8/ (M-Li, Na, K, NH/sub 4/)-acetylcarbamide - H/sub 2/O at 25 deg C have been studied. It is ascertained, that the systems investigated are of simple eutonic type.

76 FR 4532 - Safety Zone; 500 Yards North and South, Bank to Bank, of Position 29°48.77′ N 091°33.02′ W...

Science.gov (United States)

2011-01-26

...-AA00 Safety Zone; 500 Yards North and South, Bank to Bank, of Position 29[deg]48.77' N 091[deg]33.02' W... and South, bank to bank, of position 29[deg]48.77' N 091[deg]33.02' W, Charenton Drainage and Navigation Canal, St. Mary Parish, LA. This Safety Zone is needed to protect the general public, vessels and...

Influence of the channel electric field distribution on the polarization Coulomb field scattering in In0.18Al0.82N/AlN/GaN heterostructure field-effect transistors

International Nuclear Information System (INIS)

Yu Ying-Xia; Lin Zhao-Jun; Luan Chong-Biao; Yang Ming; Wang Yu-Tang; Lü Yuan-Jie; Feng Zhi-Hong

2014-01-01

By making use of the quasi-two-dimensional (quasi-2D) model, the current–voltage (I–V) characteristics of In 0.18 Al 0.82 N/AlN/GaN heterostructure field-effect transistors (HFETs) with different gate lengths are simulated based on the measured capacitance–voltage (C–V) characteristics and I–V characteristics. By analyzing the variation of the electron mobility for the two-dimensional electron gas (2DEG) with electric field, it is found that the different polarization charge distributions generated by the different channel electric field distributions can result in different polarization Coulomb field scatterings. The difference between the electron mobilities primarily caused by the polarization Coulomb field scatterings can reach up to 1522.9 cm 2 /V·s for the prepared In 0.18 Al 0.82 N/AlN/GaN HFETs. In addition, when the 2DEG sheet density is modulated by the drain–source bias, the electron mobility presents a peak with the variation of the 2DEG sheet density, the gate length is smaller, and the 2DEG sheet density corresponding to the peak point is higher. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Correlation Between Two-Dimensional Electron Gas Mobility and Crystal Quality in AlGaN/GaN High-Electron-Mobility Transistor Structure Grown on 4H-SiC.

Science.gov (United States)

Heo, Cheon; Jang, Jongjin; Lee, Kyngjae; So, Byungchan; Lee, Kyungbae; Ko, Kwangse; Nam, Okhyun

2017-01-01

We investigated the correlation between the crystal quality and two-dimensional electron gas (2DEG) mobility of an AlGaN/GaN high-electron-mobility transistor (HEMT) structure grown by metal-organic chemical vapor deposition. For the structure with an AlN nucleation layer grown at 1100 °C, the 2DEG mobility and sheet carrier density were 1627 cm²/V·s and 3.23 × 10¹³ cm⁻², respectively, at room temperature. Further, it was confirmed that the edge dislocation density of the GaN buffer layer was related to the 2DEG mobility and sheet carrier density in the AlGaN/GaN HEMT.

Radio sensibility of listeria monocytogenes in pure culture and frozen contaminated shrimps and stored them at -18 deg C

International Nuclear Information System (INIS)

Rubio M V, T.; Espinoza, J.; L Sanchez, M.V.

1997-01-01

Full text: Listeria monocytogenes has been recognized for a number of years as a food pathogen bacteria. Ionizing radiation is a new technology and an excellent method to eliminate this microorganism form frozen food. The sensitivity of Listeria monocytogenes serotype 01 and 04 to irradiation, in pure culture and frozen shrimps was investigated. The D 10 values were of 0,26-0,37 kGy in pure culture and frozen shrimps, respectively. The D 10 founded were similar to those reported by the literature under similar conditions. Doses of 6 kGy were enough to eliminate a contamination of 10 6 -10 7 ufc/ml of L. Monocytogenes in frozen shrimps and storage them during 200 days at 18 deg C

Acidity of cations and the solubility of oxides in the eutectic KCl-LiCl melt at 700 Deg C

International Nuclear Information System (INIS)

Cherginets, V.L.; Rebrova, T.P.

1999-01-01

Products of MgO, NiO and CoO solubility in KCl-LiCl melt at 700 Deg C were determined by the method of potentiometric titration using Pt(O 2 )IZrO 2 (Y 2 O 3 ) membrane oxygen electrode. It was ascertained that acid properties of Cd 2+ and Pb'2 + cations are levelled to Li + properties, a break in E-pO graduation dependence in KCl-LiCl melt was observed at pO ∼ 2. Increase in oxides solubility in the melt studied compared with KCl-NaCl and CsCl-KCl-NaCl melts stems from the presence of Li + cations in the melt studied, which possess stronger acid properties than those of Na + or K + [ru

SURVEY METHODS FOR EARTHQUAKE DAMAGES IN THE "CAMERA DEGLI SPOSI" OF MANTEGNA (MANTOVA

Directory of Open Access Journals (Sweden)

E. Fratus de Balestrini

2013-07-01

Full Text Available Cultural Heritage constitutes a fundamental resource for all Countries, even in economic terms, as it can be considered an extraordinary tourist attraction. This is particularly true for Italy, which is one of the Countries with the richest artistic heritage in the world. For this reason, restoration becomes an essential step towards the conservation and therefore valorisation of architecture. In this context, this paper focuses on one of the first stages that allow us to reach a complete knowledge of a building. Because of the earthquake of May 2012, the Castle of San Giorgio in Mantova (Italy presented a series of structural damages. On the occasion of its upcoming re-opening to the public, the Soprintendenza per i Beni Architettonici e Paesaggistici per le province di Brescia, Cremona e Mantova has requested an analysis and evaluation of the damages for the development of an intervention project. In particular, a special attention was given to the "Camera degli Sposi" ("Bridal Chamber", also known as the Camera picta ("painted chamber". It is a frescoed room, with illusionistic paintings by Andrea Mantegna, located in the northeast tower of the Castle. It was painted between 1465 and 1474 and commissioned by Ludovico Gonzaga, and it is well-known for the use of trompe l'oeil details and for the decoration of its ceiling. The seismic shakes damaged the wall decorated with the "Scena della Corte" ("Court Scene", above the chimney, re-opening an old crack that had to be analysed, in order to understand whether the damage was structural or just superficial. The diagnostic analyses constitute a fundamental prerequisite for the elaboration of any kind of intervention or restoration in any architectural, artistic or archaeological framework. To obtain a description of the conservation state of the Camera, non-invasive integrated survey techniques were applied. The purpose of the study presented here is the definition of a methodology able to support

Isoscalar giant resonances for nuclei with mass between 56 and 60

International Nuclear Information System (INIS)

Lui, Y.-W.; Youngblood, D.H.; Clark, H.L.; Tokimoto, Y.; John, B.

2006-01-01

The giant resonance region from 10 MeV x 56 Fe, 58 Ni, and 60 Ni has been studied with inelastic scattering of 240 MeV α particles at small angles, including 0 deg. Most of the expected isoscalar E0 and E2 strength has been identified below E x =40 MeV. Between 56 and 72% of the isoscalar E1 strength has been located in these nuclei. The mass dependence of the giant monopole energy between A=40 and 90 is compared to relativistic and nonrelativistic calculations for interactions with compressibility of nuclear matter K NM ∼211-225 MeV

Development of a model for the anodic behavior of T60 titanium in chlorinated and oxygenated aqueous media. Application to the specific conditions of hydrothermal oxidation (1 MPadeg. Cdeg. C)

International Nuclear Information System (INIS)

Frayret, C.; Jaszay, Th.; Lestienne, B.; Delville, M.H.

2003-01-01

This work evaluates the anodic electrochemical behavior of titanium metal in hydrothermal oxidation conditions (up to 400 deg. C and 28 MPa) in chlorinated media in order to estimate the supercritical water oxidation reactors reliability for the treatment of less than 10% organic-waste waters. The titanium room temperature dissolution mechanism in chlorinated acidic medium (pH 2 oxide formation with a very limited tetravalent dissolution). In hydrothermal oxidation (pH>1), only the second branch is effective. The titanium protection is directly related to the oxide stability in high pH systems. The mechanism model is expressed in terms of 'current-potential' laws, which provide kinetic parameters using optimization calculations. The different elementary steps reaction rates were estimated as well as the evolution of the reaction intermediates coverage ratios with the potential. The quantification of each elementary step was performed to understand and/or orient the materials behavior according to different factors (pH, chloride ions contents, potentials...)

HTTR operation monitoring with neural network in 30 days operation at 850degC

International Nuclear Information System (INIS)

Shimizu, Atsushi; Nabeshima, Kunihiko; Nakagawa, Shigeaki

2009-01-01

The High temperature engineering test reactor (HTTR) executed the rated power operation for 30days of the first time (850degC in temperature of the nuclear reactor outlet coolant) until March, 27th through April, 26th, 2007. In this operation, HTTR was observed according to the operation monitoring model with the neural network, and the detection performance of neural network was verified during slight changes of reactor state at rated power. The neural network used for the operation monitoring was an auto-associative network, where 31 input 31 outputs and the hidden layers were connected with 20 units by the hierarchy of three layer structure. Back-propagation algorithm was used for study rule. The operation monitoring model in initial study was constructed by using the power up data between 30% and rated power, which were randomly studied. The adjustment study during the operation monitoring changes the internal structure of the initial study model to follow the changes of reactor status, such as the burn-up of the nuclear fuel for the rated power operation. As a monitoring result, slight changes of reactor state by the control system operation were correctly detected, and the on-line application to an early anomaly diagnosis for HTTR facilities will be expected. (author)

Influence of deuterium content on tensile behavior of Zr-2.5Nb pressure tube material in the temperature range of ambient to 300 degC

International Nuclear Information System (INIS)

Bind, A.K.; Singh, R.N.; Chakravartty, J.K.; Dhandharia, Priyesh; Ghosh, Agnish; More, Nitin S.; Chhatre, A.G.; Vijayakumar, S.

2011-08-01

Tensile properties of autoclaved zirconium-2.5 wt. % niobium pressure tube material were evaluated by uniaxial tension tests at temperatures between 25 and 300 degC and under strain-rates of 1.075 x 10 -4 /s. Six number of Zr-2.5Nb alloy pressure tube spools of length 130 mm were obtained from pressure tube number 19-2557-2. Five spools were polished with abrasive paper to remove the oxide layer. These spools were gaseously charged with controlled amount of deuterium. The target deuterium concentrations were 25, 50, 75, 100 and 200 wppm of hydrogen equivalent. Ten samples were machined by EDM wire cutting from every spool. The tensile specimen axis was oriented along longitudinal direction of the tube. Metallographic examination of the deuterium charged samples suggested that the deuterides were predominantly circumferential deuterides. Analysis of tensile results showed that both yield and ultimate tensile strengths of this alloy decreased monotonically with increasing test temperatures. The tensile ductility decreased marginally with increase in test temperature from ambient to 300 degC. It was also observed that both strength and ductility appear to be unaffected by deuterium content at all temperatures, thereby suggesting that at least up to 200 wppm (Heq.) of deuterium tensile properties are not influenced by deuterium. (author)

Double differential cross-sections of (n,{alpha}) reactions in aluminium and nickel at 14.77 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Lalremruata, B.; Dhole, S.D. [Department of Physics, University of Pune, Pune-411007 (India); Ganesan, S. [Reactor Physics Design Division, BARC, Mumbai-400085 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune-411007 (India)], E-mail: vnb@physics.unipune.ernet.in

2009-04-15

The double differential cross-sections (DDX) for the emission of alpha particles from {sup 27}Al(n,{alpha}){sup 24}Na and Ni(n,{alpha}) reactions induced by 14.77 MeV neutrons were estimated from the alpha particle spectra recorded at 30 deg., 50 deg., 90 deg., 110 deg. angles for aluminium, and at 20 deg., 45 deg., 90 deg., 110 deg. for natural nickel. The results indicate that the alpha particles below and around the most probable energies ({approx}6.3 MeV from aluminium and {approx}8 MeV from natural nickel) are emitted predominantly through the compound nucleus formation process, and the higher energy alpha particles are emitted through the pre-equilibrium or the direct reaction. In general, the measured double-differential cross-sections are in agreement with the theoretical cross-sections estimated using Talys-1.0 and Preco2007 computer programs. The present value of the level density parameter for {sup 24}Na is close to the literature value and, therefore, these results reveal consistency in the alpha particle spectra recorded with a single silicon surface barrier detector at different scattering angles.

Synthesis of ceramic powders of La{sub 9,56} (SiO{sub 4}){sub 6}O{sub 2,34} and La{sub 9,8}Si{sub 5,7}Mg{sub O,3}O{sub 26,}4 by modified sol-gel process; Sintese de pos ceramicos de La{sub 9,56} (SiO{sub 4}){sub 6}O{sub 2,34} e La{sub 9,8}Si{sub 5,7}Mg{sub O,3}O{sub 26,}4 por processo sol-gel modificado

Energy Technology Data Exchange (ETDEWEB)

Lira, Sabrina Lopes; Paiva, Mayara Rafaela Soares; Misso, Agatha Matos; Elias, Daniel Ricco; Yamagata, Chieko, E-mail: yamagata@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

2012-07-01

Lanthanum silicate oxyapatite materials are promising for application as electrolyte in solid oxide fuel cells because of high ionic conductivity at temperatures between 600 deg C and 800 deg C. In this work, oxyapatites with the composition La{sub 9,56}(SiO{sub 4}){sub 6}O{sub 2,34}, and La{sub 9,8}Si{sub 5,7}Mg{sub 0,3}O{sub 26,4} were synthesized by using the sol-gel method, followed by precipitation. Initially, the gel of silica was synthesized from sodium silicate solution, by acid catalysis using lanthanum and magnesium chloride solution. Then, the La and Mg hydroxides were precipitated with NaOH in the gel. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and measurements of specific surface area. The crystalline oxyapatite phase of La{sub 9,56}(SiO{sub 4}){sub 6}O{sub 2,34}, and was La{sub 9,8}Si{sub 5,7}Mg{sub 0,3}O{sub 26,4} obtained by calcination at 900 deg C for 2 and 1h respectively (author)

Hydrothermal oxidation of an epoxy resin through the study of two model molecules: N-methyl-acetamide and N,N-di[1(phenoxy)2-hydroxy propyl-3] propyl-amine; Oxydation hydrothermale d'une resine epoxyde au travers de l'etude de deux molecules modeles: le N-methylacetamide et la N,N-di[1-(phenoxy) 2-hydroxy propyl-3] propylamine

Energy Technology Data Exchange (ETDEWEB)

Moutonnet-Fromonteil, C. [CEA/Cadarache, Dept. d' Etudes des Combustibles (DEC), 13 - Saint-Paul-lez-Durance (France)]|[Bordeaux-1 Univ., 33 (France)

2000-07-01

The study consists in choosing and developing a technology to realize damage experiments of an epoxy resin which is used as coating of embedded nuclear samples. Hydrothermal oxidation is the chosen method. We first identified the chemical composition of the epoxy resin. Then we studied hydrolysis and oxidation of a molecule which contains a function of the epoxy network: N-methyl-acetamide. The comparison between our results and those already existing allowed to validate this degradation method. In a second part, we studied a model molecule of the polymer network: N, N-di[1(phenoxy)2-hydroxy propyl-3] propyl-amine. The hydrolysis temperatures are relatively high: the compound is totally destroyed at 300 deg C. Its oxidation leads to the formation of acetic acid from 220 deg C. In the third study, we determined the best experimental conditions to destroy the epoxy resin. Experiments were performed at different temperatures between 200 deg C and 410 deg C. The degradation rates are classically defined by amounts of constituents in liquid and gaseous phases. (author)

Ionic association and interspecies interactions of 1-1 electrolytes in ethyl acetate solutions at 5-45 deg C

International Nuclear Information System (INIS)

Kalugin, O. N.; Panchenko, V. G.; V'yunnik, I. N.

2005-01-01

The data of conductometric studies of LiClO 4 , NaClO 4 , NaBPh 4 , and Bu 4 NClO 4 solutions in ethylacetate in the temperature range 5 to 45 deg C are reported. The constants of ionic association resulting in formation of ion pairs and triple ions, as well as limiting molar electric conductivities of the ions and triple ions are determined. It is found that the formation of contact triple ions having mutually interpenetrated structural elements in cavities of each others is characteristic of electrolytes with bulky organic ions. Anomalous temperature dependence of dynamic sizes of the [Na 2 BPh 4 ] + and [Na(BPh 4 ) 2 ] - ions and substantial differences in energy characteristics of inter-ion interactions are revealed during formation of ion pairs and triple ions in ethylacetate solutions of NaBPh 4 [ru

Hydrothermal oxidation of an epoxy resin through the study of two model molecules: N-methyl-acetamide and N,N-di[1(phenoxy)2-hydroxy propyl-3] propyl-amine

International Nuclear Information System (INIS)

Moutonnet-Fromonteil, C.

2000-01-01

The study consists in choosing and developing a technology to realize damage experiments of an epoxy resin which is used as coating of embedded nuclear samples. Hydrothermal oxidation is the chosen method. We first identified the chemical composition of the epoxy resin. Then we studied hydrolysis and oxidation of a molecule which contains a function of the epoxy network: N-methyl-acetamide. The comparison between our results and those already existing allowed to validate this degradation method. In a second part, we studied a model molecule of the polymer network: N, N-di[1(phenoxy)2-hydroxy propyl-3] propyl-amine. The hydrolysis temperatures are relatively high: the compound is totally destroyed at 300 deg C. Its oxidation leads to the formation of acetic acid from 220 deg C. In the third study, we determined the best experimental conditions to destroy the epoxy resin. Experiments were performed at different temperatures between 200 deg C and 410 deg C. The degradation rates are classically defined by amounts of constituents in liquid and gaseous phases. (author)

Study of interaction in the Pb(NO3)2-Cs3[Fe(CN)6]-H2O at 25 deg C

International Nuclear Information System (INIS)

Slivko, T.A.; Stepina, S.B.; Poletaev, I.F.; Golikova, N.B.

1982-01-01

The method of ''residual concentrations'' has been used to study the interaction in the lead nitrate-cesium hexacyanoferrate (3)-water system at 25 deg C. It is shown, that only one compound CsPb[Fe(CN) 6 ]x4H 2 O is formed in the studied range of the concentrations. Chemical and thermogravimetric analysis and infrared spectroscopy have been used at the determination of the compound composition. Thermolysis of the compound in the air is studied. Identification of the hydrated and waterless compound is accomplished with the help of the diffractometer DRON-1. The rate of the formation of mixed cesium hexacyanoferrates (3) with lead, zinc and nickel is compared

X-ray properties of the Be/X-ray systems 2S0114+650 LSI+65 deg 010

International Nuclear Information System (INIS)

Koenigsberger, G.; Swank, J.H.; Szymkowiak, A.E.

1982-12-01

Results are presented from experiments on the Einstein Observatory, HEAO-1 and OSO-8 on the temporal and spectral properties of 2S0114+650. In a 12 hour Einstein MPC and SSS observation two episodes of flaring occurred by an order of magnitude over about 1 hour. Variability on shorter time scales showed a preferred period of 14.9 minutes, but periodic pulsations were not seen in the HEAO-1 and OSO-8 data. There is some evidence that the spectrum is steeper when the source is quiescent at low luminosity, but no large spectral changes attended the flares. Absorption column densities were consistent with interstellar reddening of the proposed companion, the Be star LSI+65 deg 010. In the minute and hour variability and in the spectral character, 2S0114+650 is similar to other Be star-neutron star binary X-ray sources. Variations over several days in the OSO-8 data suggest orbital effects

Thermal analysis on the specimens for low irradiation temperature below 100degC in the HANARO

Energy Technology Data Exchange (ETDEWEB)

Choi, Myoung-Hwan; Kim, Bong-Goo; Lee, Byung-Chul; Kim, Tae-Kyu [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

2012-03-15

A capsule has been used for an irradiation test of various nuclear materials in the research reactor, HANARO. As a part of the research reactor development project with a plate type fuel, the irradiation tests of beryllium, zircaloy-4 and graphite materials using the capsule will be carried out to obtain the mechanical characteristics at low temperatures below 100degC with 30 MW reactor power. In this study, in order to obtain the preliminary design data of the capsule with various specimens and the temperature of specimens, a thermal analysis is performed by using an ANSYS program. The finite element models for the cross section of the capsule containing the specimen are generated, and the temperatures are evaluated. The analysis results show that most specimens meet the irradiation target temperature. However, some canned graphite specimens have a slightly high temperature, and the gap size has a significant effect on the specimen temperature. Based on those results a detailed design and analysis of the capsule will be completed this year. (author)

The problem in 180 deg data sampling and radioactivity decay correction in gated cardiac blood pool scanning using SPECT

International Nuclear Information System (INIS)

Ohtake, Tohru; Watanabe, Toshiaki; Nishikawa, Junichi

1986-01-01

In cardiac blood pool scanning using SPECT, half 180 deg data collection (HD) vs. full 360 deg data collection (FD) and Tc-99m decay are problems in quantifying the ejection count (EC) (end-diastolic count - end-systolic count) of both ventricles and the ratio of the ejection count of the right and left ventricles (RVEC/LVEC). We studied the change produced by altering the starting position of data sampling in HD scans. In our results of phantom and 4 clinical cases, when the cardiac axis deviation was not large and there was not remarkable cardiac enlargement, the change in LVEC, RVEC and RVEC/LVEC was small (1 - 4 %) within 12 degree change of the starting position, and the difference between the results of HD scan with a good starting position (the average of LV peak and RV peak) and FD scan was not large (less than 7 %). Because of this, we think HD scan can be used in those cases. But when the cardiac axis deviation was large or there was remarkable cardiac enlargement, the change of LVEC, RVEC and RVEC/LVEC was large (more than 10 %) even within 12 degree change of the starting position. So we think FD scan would be better in those cases. In our results of 6 patients, the half-life of Tc-99m labeled albumin in blood varied from 2 to 4 hr (3.03 ± 0.59 hr, mean ± s.d.). Using a program for radioactivity (RA) decay correction, we studied the change in LVEC, RVEC and LVEC/RVEC in 11 cases. When RA decay correction was performed using a halflife of 3.0 hr, LVEC increased 7.5 %, RVEC increased 8.7 % and RVEC/LVEC increased 0.9 % on the average in HD scans of 8 cases (LPO to RAO, 32 views, 60 beat/1 view). We think RA decay correction would not be needed in quantifying RVEC/LVEC in most cases because the change of RVEC/LVEC was very small. (author)

A 2500 deg ² CMB Lensing Map from Combined South Pole Telescope and Planck Data

Energy Technology Data Exchange (ETDEWEB)

Omori, Y.; Chown, R.; Simard, G.; Story, K. T.; Aylor, K.; Baxter, E. J.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H-M.; Crawford, T. M.; Crites, A. T.; Haan, T. de; Dobbs, M. A.; Everett, W. B.; George, E. M.; Halverson, N. W.; Harrington, N. L.; Holder, G. P.; Hou, Z.; Holzapfel, W. L.; Hrubes, J. D.; Knox, L.; Lee, A. T.; Leitch, E. M.; Luong-Van, D.; Manzotti, A.; Marrone, D. P.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Natoli, T.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Staniszewski, Z.; Stark, A. A.; Vanderlinde, K.; Vieira, J. D.; Williamson, R.; Zahn, O.

2017-11-07

We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and \\emph{Planck} temperature data. The 150 GHz temperature data from the $2500\\ {\\rm deg}^{2}$ SPT-SZ survey is combined with the \\emph{Planck} 143 GHz data in harmonic space, to obtain a temperature map that has a broader $\\ell$ coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential $C_{L}^{\\phi\\phi}$, and compare it to the theoretical prediction for a $\\Lambda$CDM cosmology consistent with the \\emph{Planck} 2015 data set, finding a best-fit amplitude of $0.95_{-0.06}^{+0.06}({\\rm Stat.})\\! _{-0.01}^{+0.01}({\\rm Sys.})$. The null hypothesis of no lensing is rejected at a significance of $24\\,\\sigma$. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, $C_{L}^{\\phi G}$, between the SPT+\\emph{Planck} lensing map and Wide-field Infrared Survey Explorer (\\emph{WISE}) galaxies. We fit $C_{L}^{\\phi G}$ to a power law of the form $p_{L}=a(L/L_{0})^{-b}$ with $a=2.15 \\times 10^{-8}$, $b=1.35$, $L_{0}=490$, and find $\\eta^{\\phi G}=0.94^{+0.04}_{-0.04}$, which is marginally lower, but in good agreement with $\\eta^{\\phi G}=1.00^{+0.02}_{-0.01}$, the best-fit amplitude for the cross-correlation of \\emph{Planck}-2015 CMB lensing and \\emph{WISE} galaxies over $\\sim67\\%$ of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey (DES), whose footprint nearly completely covers the SPT $2500\\ {\\rm deg}^2$ field.

Effects of the strain relaxation of an AlGaN barrier layer induced by various cap layers on the transport properties in AlGaN/GaN heterostructures

International Nuclear Information System (INIS)

Liu Zi-Yang; Zhang Jin-Cheng; Duan Huan-Tao; Xue Jun-Shuai; Lin Zhi-Yu; Ma Jun-Cai; Xue Xiao-Yong; Hao Yue

2011-01-01

The strain relaxation of an AlGaN barrier layer may be influenced by a thin cap layer above, and affects the transport properties of AlGaN/GaN heterostructures. Compared with the slight strain relaxation found in AlGaN barrier layer without cap layer, it is found that a thin cap layer can induce considerable changes of strain state in the AlGaN barrier layer. The degree of relaxation of the AlGaN layer significantly influences the transport properties of the two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures. It is observed that electron mobility decreases with the increasing degree of relaxation of the AlGaN barrier, which is believed to be the main cause of the deterioration of crystalline quality and morphology on the AlGaN/GaN interface. On the other hand, both GaN and AlN cap layers lead to a decrease in 2DEG density. The reduction of 2DEG caused by the GaN cap layer may be attributed to the additional negative polarization charges formed at the interface between GaN and AlGaN, while the reduction of the piezoelectric effect in the AlGaN layer results in the decrease of 2DEG density in the case of AlN cap layer. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Optical and structural characterization of GaN thin films at different N to Ga flux ratios

International Nuclear Information System (INIS)

El-Naggar, Ahmed M.

2011-01-01

GaN films were grown on Si(111) substrates under various beam equivalent pressure (BEP) ratios by plasma-assisted molecular beam epitaxy. The optical properties for the grown samples were studied over a wide spectral range from 200 to 3300 nm using the reflectance spectrum only. It was found that increasing the N/Ga BEP ratio from 17.9 to 46.1 increases the refractive index (n) from 2.05 to 2.38 at wavelength 630 nm (for example), while the optical energy gap (E g ) were found to be in the range between 3.325 to 3.35 eV with no specific trend. The structural properties for the grown films were studied through two types of rocking curve measurements; normal rocking curve (ω-scan) and triple axis rocking curve (ω/2θ-scan). It was found that with decreasing the N/Ga ratio from 46.1 to 17.9 the full width at half maximum decreases from 0.62 deg. to 0.58 deg. for ω-scan and from 0.022 deg. to 0.021 deg. for ω/2θ-scan. Thus, our results showed a clear correlation between the optical-structural parameters and the BEP ratios of N and Ga.

Enhancement of tributyltin degradation under natural light by N-doped TiO{sub 2} photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Bangkedphol, S., E-mail: sornnarin.bangkedphol@strath.ac.uk [David Livingstone Centre for Sustainability, Department of Civil Engineering, University of Strathclyde, Glasgow, Scotland G1 1XN (United Kingdom); Keenan, H.E. [David Livingstone Centre for Sustainability, Department of Civil Engineering, University of Strathclyde, Glasgow, Scotland G1 1XN (United Kingdom); Davidson, C.M. [WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, Scotland G1 1XL (United Kingdom); Sakultantimetha, A. [David Livingstone Centre for Sustainability, Department of Civil Engineering, University of Strathclyde, Glasgow, Scotland G1 1XN (United Kingdom); Sirisaksoontorn, W.; Songsasen, A. [Department of Chemistry and Centre for Innovation in chemistry, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand)

2010-12-15

Photo-degradation of tributyltin (TBT) has been enhanced by TiO{sub 2} nanoparticles doped with nitrogen (N-doped TiO{sub 2}). The N-doped catalyst was prepared by a sol-gel reaction of titanium (IV) tetraisopropoxide with 25% ammonia solution and calcined at various temperatures from 300 to 600 deg. C. X-ray diffraction results showed that N-doped TiO{sub 2} remained amorphous at 300 deg. C. At 400 deg. C the anatase phase occurred then transformed to the rutile phase at 600 deg. C. The crystallite size calculated from Scherrer's equation was in the range of 16-51 nm which depended on the calcination temperature. N-doped TiO{sub 2} calcined at 400 deg. C which contained 0.054% nitrogen, demonstrated the highest photocatalytic degradation of TBT at 28% in 3 h under natural light when compared with undoped TiO{sub 2} and commercial photocatalyst, P25-TiO{sub 2} which gave 14.8 and 18% conversion, respectively.

Theoretical evaluation of two dimensional electron gas characteristics of quaternary AlxInyGa1-x-yN/GaN hetero-junctions

Science.gov (United States)

Rahbardar Mojaver, Hassan; Manouchehri, Farzin; Valizadeh, Pouya

2016-04-01

The two dimensional electron gas (2DEG) characteristics of gated metal-face wurtzite AlInGaN/GaN hetero-junctions including positions of subband energy levels, fermi energy level, and the 2DEG concentration as functions of physical and compositional properties of the hetero-junction (i.e., barrier thickness and metal mole-fractions) are theoretically evaluated using the variational method. The calculated values of the 2DEG concentration are in good agreement with the sparsely available experimental data reported in the literature. According to our simulation results, a considerable shift in the positive direction of threshold voltage of AlInGaN/GaN hetero-junction field-effect transistors can be achieved by engineering both the spontaneous and the piezoelectric polarizations using a quaternary AlInGaN barrier-layer of appropriate mole-fractions.

Membrane processes for the treatment of exhausted effluents from leather industry; Processi a membrana per il trattamento degli effluenti esausti dell'industria conciaria

Energy Technology Data Exchange (ETDEWEB)

Cassano, A.; Molinari, R.; Drioli, E. [Arcavata di Rende Univ. della Calabria, Arcavata di Rende, CS (Italy). Istituto di Ricerca su Membrane e Modellistica di Reattori Chimici

2001-03-01

This paper considers the potentiality of some membrane processes such as ultrafiltration (UF), nano filtration (NF) and reverse osmosis (RO), in the treatment of exhausted effluents produced by the tanning cycle, based on the experimental results of the Research Group. [Italian] In questo studio vengono analizzate le potenzialita' applicative di alcuni processi a membrana, quali ultrafiltrazione (UF), nanofiltrazione (NF) e osmosi inversa (Ol), nel trattamento degli effluenti esausti del ciclo conciario, sulla base di risultati sperimentali del gruppo di ricerca del Cnr-Irmerc.

Grain-boundary sliding in a TiAl alloy with fine-grained duplex microstructure during 750 deg. C creep

Energy Technology Data Exchange (ETDEWEB)

Peter, D. [Ruhr University Bochum, Institute for Materials, D-44780 Bochum (Germany); Viswanathan, G.B., E-mail: Viswanathan.11@osu.edu [Ruhr University Bochum, Institute for Materials, D-44780 Bochum (Germany) and Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210 (United States); Wagner, M.F.-X.; Eggeler, G. [Ruhr University Bochum, Institute for Materials, D-44780 Bochum (Germany)

2009-06-15

Constant-load creep experiments at a temperature of 750 deg. C and a nominal stress of 300 MPa were conducted on a fine-grained Ti-45Al-5Nb-0.2B-0.2C (in at.%) alloy with a duplex microstructure. Microstructures before and after creep (accumulated strain: 9.6%) were analyzed using scanning and transmission electron microscopy (SEM and TEM). TEM analysis after creep indicates that the individual microstructural constituents of the fine duplex microstructure, namely, the equiaxed {gamma} and the lamellar {alpha}{sub 2}/{gamma} colonies, undergo varying degrees of deformation and develop various substructures. Lamellar grains deform by dislocation creep. They show clear evidence for dislocation and twin activity. In contrast, only few dislocations are found in the equiaxed grains. We show that the regions with small equiaxed {gamma} grains, representing 65-75 vol.% of the microstructure, deform by grain-boundary sliding.

The Effect of Material Variability on Fatigue Behaviors of Low Alloy Steels in 310 .deg. C Deoxygenated Water

International Nuclear Information System (INIS)

Jang, Hun; Jang, Changheui; Kim, Insup; Cho, Hyunchul

2008-01-01

As environmental fatigue damage is one of the main crack initiation mechanisms in nuclear power plants (NPPs), it is most important factor to assess the integrity and safety of NPPs. So, based on extensive researches, argon nation laboratory (ANL) suggested the statistical model to predict fatigue life of low alloy steels (LASs) which are widely used as structural material in NPPs. Also, we reported the environmental fatigue behaviors of SA508 Gr.1a LAS. However, from comparison between our experimental fatigue data and ANL's statistical model, our fatigue life data showed poor agreement with the ANL's statistical model. In this regard, the additional low cycle fatigue (LCF) tests were performed in 310 .deg. C deoxygenated water, and compared with ANL's statistical model to evaluate reliability of the data. And then, the effect of material variability on the fatigue life of LASs was investigated through microstructure analysis

Grain-boundary sliding in a TiAl alloy with fine-grained duplex microstructure during 750 deg. C creep

International Nuclear Information System (INIS)

Peter, D.; Viswanathan, G.B.; Wagner, M.F.-X.; Eggeler, G.

2009-01-01

Constant-load creep experiments at a temperature of 750 deg. C and a nominal stress of 300 MPa were conducted on a fine-grained Ti-45Al-5Nb-0.2B-0.2C (in at.%) alloy with a duplex microstructure. Microstructures before and after creep (accumulated strain: 9.6%) were analyzed using scanning and transmission electron microscopy (SEM and TEM). TEM analysis after creep indicates that the individual microstructural constituents of the fine duplex microstructure, namely, the equiaxed γ and the lamellar α 2 /γ colonies, undergo varying degrees of deformation and develop various substructures. Lamellar grains deform by dislocation creep. They show clear evidence for dislocation and twin activity. In contrast, only few dislocations are found in the equiaxed grains. We show that the regions with small equiaxed γ grains, representing 65-75 vol.% of the microstructure, deform by grain-boundary sliding.

Evaluation of the potential of red mud heat treated at 400 deg C in adsorption of textile dyes

International Nuclear Information System (INIS)

Antunes, M.L.P.; Rangueri, T.B.

2011-01-01

The production of aluminum metal generates a huge amount of red mud as industrial waste. The storage of such material causes serious environmental damage and needs large area for your disposal. Develop technologies that allow its reuse is an alternative. Studies show that the mud has adsorbent properties and may be used in the treatment of wastewater, gas and textiles. This work presents the characterization by X-ray diffraction and surface area of the red mud Brazilian thermally activated at 400 deg C to evaluate the adsorption capacity of this material to the dye reactive blue 19 in pH 4. Through the construction of the Langmuir isotherm was determined adsorption capacity, which, in alkaline media, got an average of 136.9 mg / g. The results suggest that under certain conditions, the red mud has potential as an alternative adsorbent and low cost. (author)

Maps of the Southern Millimeter-wave Sky from Combined 2500 deg$^2$ SPT-SZ and Planck Temperature Data

Energy Technology Data Exchange (ETDEWEB)

Chown, R.; et al.

2018-03-28

We present three maps of the millimeter-wave sky created by combining data from the South Pole Telescope (SPT) and the Planck satellite. We use data from the SPT-SZ survey, a survey of 2540 deg$^2$ of the the sky with arcminute resolution in three bands centered at 95, 150, and 220 GHz, and the full-mission Planck temperature data in the 100, 143, and 217 GHz bands. A linear combination of the SPT-SZ and Planck data is computed in spherical harmonic space, with weights derived from the noise of both instruments. This weighting scheme results in Planck data providing most of the large-angular-scale information in the combined maps, with the smaller-scale information coming from SPT-SZ data. A number of tests have been done on the maps. We find their angular power spectra to agree very well with theoretically predicted spectra and previously published results.

Razionalizzazione dell'utilizzo degli antibiotici nell'Azienda Ospedaliera Policlinico di Bari

Directory of Open Access Journals (Sweden)

D. De Vito

2003-05-01

Full Text Available

Obiettivi: scopo del nostro lavoro è stato valutare la frequenza dei microrganismi patogeni nelle Unità Operative più rappresentative dell’A.O. Policlinico di Bari e valutare l’appropriatezza delle prescrizioni antibiotiche in relazione agli esami microbiologici effettuati dal luglio 1999 al giugno 2000.

Metodi: nel periodo considerato sono stati esaminati gli isolamenti microbici, con i relativi antibiogrammi, effettuati presso l’Istituto di Igiene, Cattedra II, della Facoltà di Medicina, Università di Bari, provenienti dalle Unità Operative di Rianimazione, Malattie Infettive, Nefrologia e Urologia, Cliniche Mediche e Cliniche Chirurgiche dell’Azienda Ospedaliera. È stato effettuato un successivo confronto con i dati ricavati dall’analisi delle richieste di prescrizione antibiotica effettuate dalle cliniche considerate e pervenute presso il Servizio di Farmacia nello stesso periodo. I dati sono stati archiviati ed analizzati con Excel X per Macintosh.

Risultati: sono stati isolati in totale 2.126 microrganismi patogeni, 1.491 (70% gram negativi e 635
(30% gram positivi. Il 34,0% degli isolamenti proveniva
dalla Rianimazione, il 23,0% dalle Cliniche Chirurgiche, il 12,6% dalle Cliniche Mediche, il 10,2% dall’Urologia e Nefrologia, il 10,0% dalle Malattie Infettive ed il 9,7% dalla Medicina Generale. Per ogni Clinica sono stati valutati i principali ceppi circolanti con le relative sensibilità antibiotiche. I dati raccolti sono stati confrontati con quelli relativi alle richieste di fornitura di antibiotici pervenute dalle cliniche indagate al Servizio di Farmacia, dell’Azienda
Ospedaliera, nello stesso periodo.

Conclusioni: dall’analisi dei dati si evidenzia una notevole discrepanza tra le sensibilità agli antibiotiotici saggiati in laboratorio ed i farmaci utilizzati nelle cliniche coinvolte nello studio. Tale

Creation and characterization of Japanese standards for myocardial perfusion SPECT. Database from the Japanese Society of Nuclear Medicine Working Group

International Nuclear Information System (INIS)

Nakajima, Kenichi; Kumita, Shinichiro; Ishida, Yoshio

2007-01-01

Standards for myocardial single-photon emission computed tomography (SPECT) adapted for a Japanese population were not available. The purpose of this study was to create standard files approved by the Japanese Society of Nuclear Medicine and to make known the characteristics of the myocardial perfusion pattern of this population. With the collaboration of nine hospitals, a total of 326 sets of exercise-rest myocardial perfusion images were accumulated from subjects with a low likelihood of cardiac diseases. The normal database included a 99m Tc-methoxyisobutylisonitrile (MIBI)/tetrofosmin myocardial perfusion study with 360 deg (n=80) and 180 deg (n=56) rotations, 201 Tl study with 360 deg (n=115) and 180 deg rotations (n=54) and a dual-isotope study with 360 deg rotation (n=27). The projection images were transferred by digital imaging and communications in medicine (DICOM) format and reconstructed and analyzed with polar maps. The projection data from multiple centers were successfully transferred to a common format for SPECT reconstruction. When the average values were analyzed using a 17-segment model, myocardial counts in the septal segment differed significantly between 180 deg and 360 deg rotation acquisitions. Regional differences were observed between men and women in the inferior and anterior regions. A tracer difference between 99m Tc and 201 Tl was also observed in some segments. The attenuation patterns differed significantly between subjects from the United States and those from Japan. Myocardial perfusion data that were specific for the Japanese population were generated. The normal database can serve a standard for nuclear cardiology work conducted in Japan. (author)

The Corrosion Behavior of Nickel and Inconel 600 in Sodium Hydroxide and Hydrochloric Acid Solution at 280 .deg. C

International Nuclear Information System (INIS)

Lee, Ihh Chong; Suk, Tae Won

1980-01-01

The corrosion behavior of nickel and Inconel 600 has been investigated by the weight change measurement method at pH ranges 3∼13 of the solution. The specimens were exposed to aqueous solutions in a static autoclave at 280 .deg. C for 210 hours. The pH of the solutions was adjusted by hydrochloric acid and sodium hydroxide and the dissolved oxygen concentration was fixed as 10 ppb by using pure nitrogen gas. Weight loss of Inconel 600 was much less than that of nickel over the tested pH ranges. At pH 9.5, nickel and Inconel 600 showed the minimum weight loss phenomenon and the values of weight loss were 1.5mg/dm 2 and 0.9mg/dm 2 , respectively. Microscopic examination showed that nickel surface was attacked uniformly, whereas Inconel 600 surface was not greatly

La dottrina degli avatara come prova per la datazione dell’Abhinayadarpana di Nandikesvara

Directory of Open Access Journals (Sweden)

Pietro Chierichetti

2012-01-01

Full Text Available Abstract - IT Come per molte opere della letteratura indiana in sanscrito, anche per l’Abhinayadarpana di Nandikesvara è difficile proporre una datazione attendibile: nel suo contributo, l’autore cerca di utilizzare un elemento interno al testo per ipotizzare il periodo nel quale il testo potrebbe collocarsi. La citazione degli avatara di Visnu, esemplificata attraverso una serie di gesti delle mani, viene vagliata criticamente al fine di un suo possibile utilizzo per collocare l’opera dal punto di vista cronologico. L’Abhinayadarpana, uno dei test fondamentali del teatro-danza in India, viene in questo modo inserito nel panorama più ampio della vicenda religiosa dell’India antica e la storia della religione hindu fornisce a sua volta uno strumento interessante per la ricostruzione della storia del testo. Abstract - EN As it often happens for many works of the Indian literature in Sanskrit, it is difficult to determine a possible dating of Nandikesvara’s iAbhinayadarpana: in his article, the author tries to assume an inner element of the text for a hypothesis about the period in which the work could be dated back to. The Visnu’s avataras, quoted in the text through a series of hand gestures, are scientifcally examined to define the work from a chronological point of view. The Abhinayadarpana, one of the most important texts of the Indian Dance-Theatre, is put in the broader landscape of the Indian ancient religion and the hindu religion history becomes an interesting tool through which the text’s history is reconstructed.

Growth and characterization of AlGaN/GaN/AlGaN double-heterojunction high-electron-mobility transistors on 100-mm Si(111) using ammonia-molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Ravikiran, L.; Radhakrishnan, K., E-mail: ERADHA@ntu.edu.sg; Yiding, Lin; Ng, G. I. [NOVITAS-Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Dharmarasu, N.; Agrawal, M.; Arulkumaran, S.; Vicknesh, S. [Temasek Laboratories@NTU, Nanyang Technological University, Singapore 637553 (Singapore)

2015-01-14

To improve the confinement of two-dimensional electron gas (2DEG) in AlGaN/GaN high electron mobility transistor (HEMT) heterostructures, AlGaN/GaN/AlGaN double heterojunction HEMT (DH-HEMT) heterostructures were grown using ammonia-MBE on 100-mm Si substrate. Prior to the growth, single heterojunction HEMT (SH-HEMT) and DH-HEMT heterostructures were simulated using Poisson-Schrödinger equations. From simulations, an AlGaN buffer with “Al” mole fraction of 10% in the DH-HEMT was identified to result in both higher 2DEG concentration (∼10{sup 13 }cm{sup −2}) and improved 2DEG confinement in the channel. Hence, this composition was considered for the growth of the buffer in the DH-HEMT heterostructure. Hall measurements showed a room temperature 2DEG mobility of 1510 cm{sup 2}/V.s and a sheet carrier concentration (n{sub s}) of 0.97 × 10{sup 13 }cm{sup −2} for the DH-HEMT structure, while they are 1310 cm{sup 2}/V.s and 1.09 × 10{sup 13 }cm{sup −2}, respectively, for the SH-HEMT. Capacitance-voltage measurements confirmed the improvement in the confinement of 2DEG in the DH-HEMT heterostructure, which helped in the enhancement of its room temperature mobility. DH-HEMT showed 3 times higher buffer break-down voltage compared to SH-HEMT, while both devices showed almost similar drain current density. Small signal RF measurements on the DH-HEMT showed a unity current-gain cut-off frequency (f{sub T}) and maximum oscillation frequency (f{sub max}) of 22 and 25 GHz, respectively. Thus, overall, DH-HEMT heterostructure was found to be advantageous due to its higher buffer break-down voltages compared to SH-HEMT heterostructure.

Growth and characterization of AlGaN/GaN/AlGaN double-heterojunction high-electron-mobility transistors on 100-mm Si(111) using ammonia-molecular beam epitaxy

International Nuclear Information System (INIS)

Ravikiran, L.; Radhakrishnan, K.; Yiding, Lin; Ng, G. I.; Dharmarasu, N.; Agrawal, M.; Arulkumaran, S.; Vicknesh, S.

2015-01-01

To improve the confinement of two-dimensional electron gas (2DEG) in AlGaN/GaN high electron mobility transistor (HEMT) heterostructures, AlGaN/GaN/AlGaN double heterojunction HEMT (DH-HEMT) heterostructures were grown using ammonia-MBE on 100-mm Si substrate. Prior to the growth, single heterojunction HEMT (SH-HEMT) and DH-HEMT heterostructures were simulated using Poisson-Schrödinger equations. From simulations, an AlGaN buffer with “Al” mole fraction of 10% in the DH-HEMT was identified to result in both higher 2DEG concentration (∼10 13  cm −2 ) and improved 2DEG confinement in the channel. Hence, this composition was considered for the growth of the buffer in the DH-HEMT heterostructure. Hall measurements showed a room temperature 2DEG mobility of 1510 cm 2 /V.s and a sheet carrier concentration (n s ) of 0.97 × 10 13  cm −2 for the DH-HEMT structure, while they are 1310 cm 2 /V.s and 1.09 × 10 13  cm −2 , respectively, for the SH-HEMT. Capacitance-voltage measurements confirmed the improvement in the confinement of 2DEG in the DH-HEMT heterostructure, which helped in the enhancement of its room temperature mobility. DH-HEMT showed 3 times higher buffer break-down voltage compared to SH-HEMT, while both devices showed almost similar drain current density. Small signal RF measurements on the DH-HEMT showed a unity current-gain cut-off frequency (f T ) and maximum oscillation frequency (f max ) of 22 and 25 GHz, respectively. Thus, overall, DH-HEMT heterostructure was found to be advantageous due to its higher buffer break-down voltages compared to SH-HEMT heterostructure

[Physical activity: results of the German Health Interview and Examination Survey for Adults (DEGS1)].

Science.gov (United States)

Krug, S; Jordan, S; Mensink, G B M; Müters, S; Finger, J; Lampert, T

2013-05-01

Regular physical activity can have a positive effect on health at any age. Today's lifestyles, however, can often be characterised as sedentary. Therefore, the promotion of physical activity and sports has become an integral part of public health measures. The representative data of adults aged 18 to 79 years in Germany obtained from the "German Health Interview and Examination Survey for Adults" (DEGS1) provide an overview of self-estimated current physical activity behaviour. The results show that one third of the adult population claims to pay close attention to reaching a sufficient level of physical activity and one fourth participates in sports for at least 2 h/week on a regular basis. Thus, the percentage of adults regularly engaged in sports has increased compared to the previous "German National Health Interview and Examination Survey 1998". Still, four out of five adults do not achieve at least 2.5 h/week of moderate-intensity physical activity as recommended by the World Health Organisation. Consequently, future individual-level and population-level interventions should focus on target group-specific measures while continuing to promote regular physical activity in all segments of the population. An English full-text version of this article is available at SpringerLink as supplemental.

Criteri di indagine degli spazi voltati nell’ambito dell’architettura storica e in archeologia

Directory of Open Access Journals (Sweden)

Luca Cipriani

2014-07-01

Full Text Available ItLo studio degli spazi voltati nell’ambito dell’architettura storica è un tema di grande interesse, che da sempre vede impegnati vari studiosi afferenti ad ambiti disciplinari diversi, dall’archeologia, alla storia dell’arte, alla conservazione. In tale contesto interdisciplinare molto spesso il ruolo di ingegneri ed architetti, che si occupano di indagare le matrici geometriche alla base della progettazione di tali spazi, viene relegato ad un ruolo accessorio rispetto a quello dei conservatori, che materialmente si occupano delle pratiche di manutenzione e di restauro. Con l’avanzare delle tecnologie di rilevamento, che spaziano con sempre maggiore affidabilità dalla documentazione dei caratteri morfologici superficiali a quelli più intrinseci alla base dei manufatti, quale può essere il ruolo attuale di chi si occupa di comprendere il progetto che generò tali ambienti? In altri termini, quel vasto patrimonio immateriale che sta alla base della concezione progettuale di un manufatto, specialmente se scaturito da una raffinata conoscenza matematica e geometrica, ha oggi un ruolo riconoscibile e sufficientemente autorevole rispetto all’ammontare di conoscenze tecniche che permettono alle “macchine” di funzionare?Con questo contributo si intende mostrare come l’integrazione di vari know-how legati sia alla modellazione reality-based che alla conoscenza dei criteri e degli strumenti di progettazione del passato, possa fornire un input sostanziale per l’intervento e per la conoscenza di manufatti caratterizzati da una evidente complessità geometrica e costruttiva. Per ricaduta si intende poi mostrare come la documentazione fine a se stessa, per quanto accurata, certificata e garantita attraverso le più avanzate tecnologie e metodologie integrate, non si configuri come base di scambio e di dialogo interdisciplinare. En The study of vaulted spaces in the context of the historic architecture is a topic of great interest

Current transport in graphene/AlGaN/GaN vertical heterostructures probed at nanoscale.

Science.gov (United States)

Fisichella, Gabriele; Greco, Giuseppe; Roccaforte, Fabrizio; Giannazzo, Filippo

2014-08-07

Vertical heterostructures combining two or more graphene (Gr) layers separated by ultra-thin insulating or semiconductor barriers represent very promising systems for next generation electronics devices, due to the combination of high speed operation with wide-range current modulation by a gate bias. They are based on the specific mechanisms of current transport between two-dimensional-electron-gases (2DEGs) in close proximity. In this context, vertical devices formed by Gr and semiconductor heterostructures hosting an "ordinary" 2DEG can be also very interesting. In this work, we investigated the vertical current transport in Gr/Al(0.25)Ga(0.75)N/GaN heterostructures, where Gr is separated from a high density 2DEG by a ∼ 24 nm thick AlGaN barrier layer. The current transport from Gr to the buried 2DEG was characterized at nanoscale using conductive atomic force microscopy (CAFM) and scanning capacitance microscopy (SCM). From these analyses, performed both on Gr/AlGaN/GaN and on AlGaN/GaN reference samples using AFM tips with different metal coatings, the Gr/AlGaN Schottky barrier height ΦB and its lateral uniformity were evaluated, as well as the variation of the carrier densities of graphene (ngr) and AlGaN/GaN 2DEG (ns) as a function of the applied bias. A low Schottky barrier (∼ 0.40 eV) with excellent spatial uniformity was found at the Gr/AlGaN interface, i.e., lower compared to the measured values for metal/AlGaN contacts, which range from ∼ 0.6 to ∼ 1.1 eV depending on the metal workfunction. The electrical behavior of the Gr/AlGaN contact has been explained by Gr interaction with AlGaN donor-like surface states located in close proximity, which are also responsible of high n-type Gr doping (∼ 1.3 × 10(13) cm(-2)). An effective modulation of ns by the Gr Schottky contact was demonstrated by capacitance analysis under reverse bias. From this basic understanding of transport properties in Gr/AlGaN/GaN heterostructures, novel vertical field effect

Analytical charge control model for AlGaN/GaN MIS-HFETs including an undepleted barrier layer

Energy Technology Data Exchange (ETDEWEB)

Shenghui, Lu; Jiangfeng, Du; Qian, Luo; Qi, Yu; Wei, Zhou; Jianxin, Xia; Mohua, Yang, E-mail: lushenghui@sohu.co [State key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

2010-09-15

An analytical charge control model considering the insulator/AlGaN interface charge and undepleted Al-GaN barrier layer is presented for AlGaN/GaN metal-insulator-semiconductor heterostructure field effect transistors (MIS-HFETs) over the entire operation range of gate voltage. The whole process of charge control is analyzed in detail and partitioned into four regions: I-full depletion, II-partial depletion, III-neutral region and IV-electron accumulation at the insulator/AlGaN interface. The results show that two-dimensional electron gas (2DEG) saturates at the boundary of region II/III and the gate voltage should not exceed the 2DEG saturation voltage in order to keep the channel in control. In addition, the span of region II accounts for about 50% of the range of gate voltage before 2DEG saturates. The good agreement of the calculated transfer characteristic with the measured data confirms the validity of the proposed model. (semiconductor devices)

General Corrosion studies of a Titanium and Incoloy based alloys under ammoniacal medium and at 290 deg. C

International Nuclear Information System (INIS)

Gokhale, B.K.; Keny, S.J.; Kumbhar, A.G.; Rangarajan, S.; Bera, S.; Nuwad Jitendra; Kumar, Sanjukta A.; Wagh, D. N.; Pradhan, S.

2012-09-01

For their use in future PWR applications, the general corrosion behaviors of two modified alloys of titanium and Incoloy were studied at high temperature and high pressure (290 deg. C, 7400 Kpa) under ammoniated atmosphere and compared. Coupons were exposed to solutions of varying ammonia concentrations of (10, 50 and 100 ppm ) at 290 deg. C under non-deaerated conditions in a static autoclave for 20 days. Surface characteristics of exposed coupons were studied using XRF, SEM, EDAX and XPS. The solution in the autoclave was analyzed for its specific conductivity, pH and for the elemental concentrations leached from alloy. The exposed titanium based alloy showed deposition of white crystalline material (300-1000 nm size) on the surface. Depletion of Ti and increase in the oxygen concentration on the exposed surface was observed. This indicated dissolution of Ti in solution from surface at high temperature and pressure and its reaction with oxygen in solution to form oxide and its redeposition on surface. The oxide film compositions were found to change drastically between 10 and 50 ppm ammoniated solution. Ti was found to be enriched in the oxide film when the solution contained 50 ppm of ammonia whereas the opposite effect was observed at 10 ppm of ammonia. The presence Ti 4+ in oxide environment and traces of Cr 3+ were observed but no nitrogen or Zr was detected. Specific conductivity of the exposed solution was found to increase by 30 μS/cm and pH to decrease by 1.5 units. Slight leaching of Ti was observed in solution. No Zr was found in the leached solution. Presence of other elements like Al, Cr, Ni in the exposed solution indicated leaching of autoclave construction material (hastelloy). This alloy showed good resistance for corrosion under the experimental conditions. The exposed surface of Incoloy based alloy showed Ni, Cr, Cu and Mn on the surface with deposition of crystalline particles (200-300 nm size). The exposed surface also showed a decrease in Cr

90 deg.Neutron emission from high energy protons and lead ions on a thin lead target

CERN Document Server

Agosteo, S; Foglio-Para, A; Mitaroff, W A; Silari, Marco; Ulrici, L

2002-01-01

The neutron emission from a relatively thin lead target bombarded by beams of high energy protons/pions and lead ions was measured at CERN in one of the secondary beam lines of the Super Proton Synchrotron for radiation protection and shielding calculations. Measurements were performed with three different beams: sup 2 sup 0 sup 8 Pb sup 8 sup 2 sup + lead ions at 40 GeV/c per nucleon and 158 GeV/c per nucleon, and 40 GeV/c mixed protons/pions. The neutron yield and spectral fluence per incident ion on target were measured at 90 deg.with respect to beam direction. Monte-Carlo simulations with the FLUKA code were performed for the case of protons and pions and the results found in good agreement with the experimental data. A comparison between simulations and experiment for protons, pions and lead ions have shown that--for such high energy heavy ion beams--a reasonable estimate can be carried out by scaling the result of a Monte-Carlo calculation for protons by the projectile mass number to the power of 0.80-0...

Observations of neutral hydrogen in the region 355 deg deg and -5 deg < bsup(II) < 5 deg

International Nuclear Information System (INIS)

Cohen, R.J.; Pedlar, A.

1974-01-01

Studies of the 21cm hydrogen line from the central regions of the Galaxy are reported. The instruments used for the study are the Mark II (31'x35' HPBW) and Mark IA (13' HPBW) radio telescopes at NRAL, Jodrell Bank

α-NiPt(Al) and phase equilibria in the Ni-Al-Pt system at 1150 deg C

International Nuclear Information System (INIS)

Hayashi, S.; Ford, S.I.; Young, D.J.; Sordelet, D.J.; Besser, M.F.; Gleeson, B.

2005-01-01

The α-NiPt(Al) phase and its associated equilibria in the Ni-Al-Pt system at 1150 deg C were investigated by analyzing equilibrated bulk alloys and the interdiffusion zones of diffusion couples. Phase constitutions, tie-lines and microstructures were determined using a combination of techniques, including high-energy synchrotron X-ray diffraction, scanning electron microscopy and electron probe microanalysis. A large Pt solubility limit was found to exist in the β-NiAl, ∼42 at.%, and in γ'-Ni 3 Al, ∼32 at.%. The α-NiPt(Al) phase was found to have wide Pt solubility range of about 33-60 at.% and to skew along an almost constant Pt/Al ratio of 1.5. The α-NiPt(Al) has an ordered face-centered tetragonal L1 0 crystal structure, with the Al and Pt atoms found to be preferentially located in the corners and prismatic faces, respectively. The temperature dependence of the lattice parameters and unit cell volume of the α phase were also determined

Atomic layer deposition of GaN at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Ozgit, Cagla; Donmez, Inci; Alevli, Mustafa; Biyikli, Necmi [UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey)

2012-01-15

The authors report on the self-limiting growth of GaN thin films at low temperatures. Films were deposited on Si substrates by plasma-enhanced atomic layer deposition using trimethylgallium (TMG) and ammonia (NH{sub 3}) as the group-III and -V precursors, respectively. GaN deposition rate saturated at 185 deg. C for NH{sub 3} doses starting from 90 s. Atomic layer deposition temperature window was observed from 185 to {approx}385 deg. C. Deposition rate, which is constant at {approx}0.51 A/cycle within the temperature range of 250 - 350 deg. C, increased slightly as the temperature decreased to 185 deg. C. In the bulk film, concentrations of Ga, N, and O were constant at {approx}36.6, {approx}43.9, and {approx}19.5 at. %, respectively. C was detected only at the surface and no C impurities were found in the bulk film. High oxygen concentration in films was attributed to the oxygen impurities present in group-V precursor. High-resolution transmission electron microscopy studies revealed a microstructure consisting of small crystallites dispersed in an amorphous matrix.

Influence of the channel electric field distribution on the polarization Coulomb field scattering in AlGaN/AlN/GaN heterostructure field-effect transistors

Directory of Open Access Journals (Sweden)

Yingxia Yu

2013-09-01

Full Text Available Using the Quasi-Two-Dimensional (quasi-2D model, the current-voltage (I-V characteristics of AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs with different gate length were simulated based on the measured capacitance-voltage (C-V characteristics and I-V characteristics. By analyzing the simulation results, we found that the different polarization charge distribution generated by the different channel electric field distribution can result in different polarization Coulomb field scattering, and the difference of the electron mobility mostly caused by the polarization Coulomb field scattering can reach up to 1829.9 cm2/V·s for the prepared AlGaN/AlN/GaN HFET. In addition, it was also found that when the two-dimension electron gas (2DEG sheet density is modulated by the drain-source bias, the electron mobility appears peak with the variation of the 2DEG sheet density, and the ratio of gate length to drain-source distance is smaller, the 2DEG sheet density corresponding to the peak point is higher.

Transcriptome Analysis of Two Rice Varieties Contrasting for Nitrogen Use Efficiency under Chronic N Starvation Reveals Differences in Chloroplast and Starch Metabolism-Related Genes

Directory of Open Access Journals (Sweden)

Subodh Kumar Sinha

2018-04-01

Full Text Available The nitrogen use efficiency (NUE of crop plants is limited and enhancing it in rice, a major cereal crop, would be beneficial for farmers and the environment alike. Here we report the genome-wide transcriptome analysis of two rice genotypes, IR 64 (IR64 and Nagina 22 (N22 under optimal (+N and chronic starvation (-N of nitrogen (N from 15-day-old root and shoot tissues. The two genotypes were found to be contrasting in their response to -N; IR64 root architecture and root dry weight remained almost equivalent to that under +N conditions, while N22 showed high foraging ability but a substantial reduction in biomass under -N. Similarly, the photosynthetic pigments showed a drastic reduction in N22 under low N, while IR64 was more resilient. Nitrate reductase showed significantly low specific activity under -N in both genotypes. Glutamate synthase (GOGAT and citrate synthase CS activity were highly reduced in N22 but not in IR64. Transcriptome analysis of these genotypes revealed nearly double the number of genes to be differentially expressed (DEGs in roots (1016 compared to shoots (571. The response of the two genotypes to N starvation was distinctly different reflecting their morphological/biochemical response with just two and eight common DEGs in the root and shoot tissues. There were a total of 385 nitrogen-responsive DEGs (106 in shoots and 279 in roots between the two genotypes. Fifty-two of the 89 DEGs identified as specific to N22 root tissues were also found to be differentially expressed between the two genotypes under -N. Most of these DEGs belonged to starch and chloroplast metabolism, followed by membrane and signaling proteins. Physical mapping of DEGs revealed 95 DEGs in roots and 76 in shoots to be present in quantitative trait loci (QTL known for NUE.

High-temperature carrier density and mobility enhancements in AlGaN/GaN HEMT using AlN spacer layer

Science.gov (United States)

Ko, Tsung-Shine; Lin, Der-Yuh; Lin, Chia-Feng; Chang, Che-Wei; Zhang, Jin-Cheng; Tu, Shang-Ju

2017-04-01

In this paper, we experimentally studied the effect of AlN spacer layer on optical and electrical properties of AlGaN/GaN high electric mobility transistors (HEMTs) grown by metal organic chemical vapor deposition method. For AlGaN layer in HEMT structure, the Al composition of the sample was determined using x-ray diffraction and photoluminescence. Electrolyte electro-reflectance (EER) measurement not only confirmed the aluminum composition of AlGaN layer, but also determined the electric field strength on the AlGaN layer through the Franz-Keldysh oscillation phenomenon. This result indicated that the electric field on the AlGaN layer could be improved from 430 to 621 kV/cm when AlN spacer layer was inserted in HEMT structure, which increased the concentration of two dimensional electron gas (2DEG) and improve the mobility. The temperature dependent Hall results show that both the mobility and the carrier concentration of 2DEG would decrease abruptly causing HEMT loss of function due to phonon scattering and carrier thermal escape when temperature increases above a specific value. Meanwhile, our study also demonstrates using AlN spacer layer could be beneficial to allow the mobility and carrier density of 2DEG sustaining at high temperature region.

Effect of Cr content on the FAC of pipe material at 150 .deg. C

International Nuclear Information System (INIS)

Park, Tae Jun; Kim, Hong Pyo

2013-01-01

Flow accelerated corrosion (FAC) of the carbon steel piping in nuclear power plants (NPPs) has been major issue in nuclear industry. During the FAC, a protective oxide layer on carbon steel dissolves into flowing water leading to a thinning of the oxide layer and accelerating corrosion of base material. As a result, severe failures may occur in the piping and equipment of NPPs. Effect of alloying elements on FAC of pipe materials was studied with rotating cylinder FAC test facility at 150 .deg. C and at flow velocity of 4m/s. The facility is equipped with on line monitoring of pH, conductivity, dissolved oxygen(DO) and temperature. Test solution was the demineralized water, and DO concentration was less than 1 ppb. Surface appearance of A 106 Gr. B which is used widely in secondary pipe in NPPs showed orange peel appearance, typical appearance of FAC. The materials with Cr content higher than 0.17wt.% showed pit. The pit is thought to early degradation mode of FAC. The corrosion product within the pit was enriched with Cr, Mo, Cu, Ni and S. But S was not detected in SA336 F22V with 2.25wt.% Cr. The enrichment of Cr and Mo seemed to be related with low, solubility of Cr and Mo compared to Fe. Measured FAC rate was compared with Ducreaux's relationship and showed slightly lower FAC rate than Ducreaux's relationship

Study of 225 deg C thermoluminescent of quartz inclusions extracted from cementitious building materials

International Nuclear Information System (INIS)

Campos, Simara S.; Almeida, Geangela M. de; Souza, Suzana O.

2009-01-01

Incidents of excessive exposure of the population to ionizing radiation could result from a nuclear explosion, the direct exposure to a source theft or loss or an accidental exposure to a source without shielding, for example. During these incidents the victims seldom are using individual protection equipment used in the measurement and control of the doses that were exposed. One of the ways found to the doses assessment due to exposure to this type of accident is the retrospective dosimetry, which determines the excessive doses of radiation exposure, whether chronological or acute, using common materials available in the public domain. The methodology for the application of retrospective dosimetry for thermoluminescence in buildings previously burned, as bricks, it is already well established. Interest is now turning to the use of cementitious building materials such as mortar and concrete to enlarge the scope of application. This study aimed to examine some of these materials and techniques for their possible application in the doses assessment from an accidental irradiation by thermoluminescence. For this the peak about 225 deg C of natural quartz and it extracted of mortar and concrete was certain your stability for the plateau and storage tests, and also the dependence of your luminescent intensity with radiation dose. Presenting a life relatively tans compared enough to that of the accumulation of natural and long radiation sign for dosimetric applications, besides other favorable characteristics, the mortar presented evidence that is possible for retrospective dosimetry through thermoluminescence. (author)

X-ray diffraction analysis of the phase transition orthorhombic-tetragonal in Y(1-x)Ca(x)Ba2Cu3O(7) superconductors dependent on the oxygen pressure at 500 and 600deg C. Etude de la transition orthorhombique-tetragonale dans les supraconducteurs Y sub 1-x Ca sub x Ba sub 2 Cu sub 3 O sub z par diffraction des rayons X en fonction de la pression d'oxygene a 500 et 600deg C

Energy Technology Data Exchange (ETDEWEB)

Touzelin, B [Lab. C.N.S., Chimie Generale, Univ. Paris 11, 91 - Orsay (France)

1991-04-15

The oxygen partial pressures and the oxygen composition z dependence of the lattice parameters of Y{sub 1-x}Ca{sub x}Ba{sub 2}Cu{sub 3}O{sub z} have been investigated by X-ray diffraction at 500 and 600deg C for 10%, 20% and 30% calcium content. The coexistence of the orthorhombic and tetragonal phases is observed in an oxygen composition range which decreases with increasing calcium content. The tetragonal phase occurs alone at the same oxygen content: z=6.745 in a temperature range of approximately 100deg C whatever the calcium content. Its structural transition will be first order with no second order at all, as undoped 1-2-3. Lastly it is noticed that the superconductivity is independent of the structural O-T transition. (orig.).

Temperature dependent diffusion and epitaxial behavior of oxidized Au/Ni/p-GaN ohmic contact

International Nuclear Information System (INIS)

Hu, C.Y.; Qin, Z.X.; Feng, Z.X.; Chen, Z.Z.; Ding, Z.B.; Yang, Z.J.; Yu, T.J.; Hu, X.D.; Yao, S.D.; Zhang, G.Y.

2006-01-01

The temperature dependent diffusion and epitaxial behavior of oxidized Au/Ni/p-GaN ohmic contact were studied with Rutherford backscattering spectroscopy/channeling (RBS/C) and synchrotron X-ray diffraction (XRD). It is found that the Au diffuses to the surface of p-GaN to form an epitaxial structure on p-GaN after annealing at 450 deg. C. At the same time, the O diffuses to the metal-semiconductor interface and forms NiO. Both of them are suggested to be responsible for the sharp decrease in the specific contact resistance (ρ c ) at 450 deg. C. At 500 deg. C, the epitaxial structure of Au develops further and the O also diffuses deeper into the interface. As a result, the ρ c reaches the lowest value at this temperature. However, when annealing temperature reaches 600 deg. C, part or all of the interfacial NiO is detached from the p-GaN and diffuses out, which cause the ρ c to increase greatly

Inchiesta sulle condizioni di vita e sanitarie degli immigrati presenti nella cittá di Messina

Directory of Open Access Journals (Sweden)

D. Alfino

2003-05-01

Full Text Available A Messina e nella sua provincia vivono circa 7328 stranieri con regolare permesso di soggiorno (dati aggiornati al 31/12/02 Questura di Messina Ufficio Immigrati ai quali si deve aggiungere una quota di soggetti, irregolari e clandestini, stimata intorno al 25% dei regolari (fonte dati Caritas, Kirone. Le Comunità maggiormente presenti sono quelle provenienti dalle Filippine, Marocco, Sri Lanka. Al fine di valutare il livello di assistenza sanitaria fornita agli immigrati, nel periodo compreso tra Dicembre 2002 e Maggio 2003, abbiamo intervistato un campione di immigrati relativamente alle loro abitudini di vita, sul tipo di lavoro svolto, sullo stato di salute attuale e pregresso, sull’eventuale ricorso alle strutture del Servizio Sanitario Locale e sulle vaccinazioni praticate nel Paese di origine e in Italia. Sono stati intervistati 1204 soggetti (42,19% Sri Lanka, 24,75% Marocco, 25,91% Filippine, 3,15% Tunisia, 1,82% Senegal, 0,16% Algeria. La comunità cinese, anch’essa significativamente presente nella città, si è dimostrata diffidente e non interessata alla nostra indagine. Sono state evidenziate notevoli carenze del Servizio Sanitario locale, per mancanza di un sistema di monitoraggio e prevenzione rivolto agli immigrati. Il 99% degli intervistati pur essendo iscritto al S.S.N.ed avendo nell’84% il medico di famiglia, non possiede il libretto sanitario, è stato sottoposto alle vaccinazioni obbligatorie del Paese di origine, ma non le ha integrate con quelle Italiane, ad eccezione del 2,3% di soggetti che ha praticato quella antiinfluenzale e dell’ 1,2% che si è sottoposto a quella antitifica ed antiepatite A per motivi occupazionali. Malgrado l’intervista mirasse a sondare il livello di assistenza sanitaria, ha svelato altri dettagli: il 79,2% dei soggetti cerca di mantenere le abitudini alimentari originarie; solo lo 0,5% ha dichiarato di aver subito un infortunio, mentre riguardo al tipo di attività svolta si rilevano

Hydrothermal crystallization in the KOH-TiO2-GeO2-H2O system at 500 deg C and 0.1 GPa

International Nuclear Information System (INIS)

Ilyushin, G.D.

2003-01-01

The identification of structural phases and crystallochemical analysis of phases in a KOH-TiO 2 -GeO 2 -H 2 O system under conditions of high temperatures and pressures are performed. A comparison is made with earlier obtained results for a system of KOH-GeO 2 (quartz-like structure)-H 2 O. It is established that K 2 Ti 6 O 13 skeleton potassium titanate is a basic phase in the system of KOH-TiO 2 -GeO 2 -H 2 O at 500 deg C and 0.1 GPa within a wide range of varying TiO 2 :GeO 2 and KOH concentrations [ru

Utilization of Passion fruit hulls (Passiflora edulis Sims f. edulis Deg as component of complete feed for growing Kacang goats

Directory of Open Access Journals (Sweden)

Kiston Simanihuruk

2009-03-01

Full Text Available Processing of passion fruit (Passiflora edulis Sims f. edulis Deg to produce passion fruit juice produce passion fruit hulls that is potential for feedstuff. Twenty male kacang goats (average initial body weight 17±1.24 kg were used in an experiment to study the effect of utilization of passion fruit hulls as feed component in the complete pellet ration on their growth. The experiment was arranged in completely randomized design consisting of 4 diets and 5 replications. Animal were randomly allocated into 4 diets (0, 15, 30, 45% level of passion fruit hulls. Each diet contained 14% crude protein and 2550 Kcal kg-1 metabolism energy. The ration was offered at 3.8% of body weight based on dry matter. The result of the experiment showed that all variables observed were not affected by level of passion fruit hulls (P>0.05. Average daily gain and feed efficiency tended to decrease with the increase level of passion fruit hulls. The highest dry matter, organic matter and N intake (768,78 g h-1 d-1; 687,37 g h-1 d-1 and 17,22 g h-1 d-1 respectively were found from R1 treatment (15% level of passion fruit hulls. It was concluded that passion fruit hulls can be used till 45% level in the diet of Kacang goat.

Dike zones on Venus

Science.gov (United States)

Markov, M. S.; Sukhanov, A. L.

1987-01-01

Venusian dike zone structures were identified from Venera 15 and 16 radar images. These include: a zone of subparallel rows centered at 30 deg N, 7 deg E; a system of intersecting bands centered at 67 deg N, 284 deg E; polygonal systems in lavas covering the structural base uplift centered at 47 deg N, 200 deg E; a system of light bands in the region of the ring structure centered at 43 deg N, 13 deg E; and a dike band centered at 27 deg N, 36 deg E.

Activation characteristics of ion-implanted Si+ in AlGaN

International Nuclear Information System (INIS)

Irokawa, Y.; Fujishima, O.; Kachi, T.; Pearton, S.J.; Ren, F.

2005-01-01

Multiple-energy Si + implantation in the range 30-360 keV into Al 0.13 Ga 0.87 N for n-type doping was carried out at room temperature, followed by annealing at 1150-1375 deg. C for 5 min. Activation efficiencies close to 100% were obtained for ion doses of 1.0x10 15 cm -2 after annealing at 1375 deg. C, with a resulting sheet resistance of 74 Ω/square. By sharp contrast, the activation efficiency at 1150 deg. C was only 4% for this dose, with a sheet resistance of 1.63x10 4 Ω/square. The activation efficiency was also a function of dose, with a maximum activation percentage of only 55% for lower doses of 1.0x10 14 cm -2 annealed at 1375 deg. C. This is due to the comparatively larger effect of compensating acceptors at the lower dose and is also lower than the corresponding activation of Si in pure GaN under these conditions (78%). The measurement temperature dependence of sheet carrier density showed an activation energy of 23 meV, consistent with the ionization energy of Si in AlGaN

The thermal expansion of a highly crystalline hexagonal BC2N compound synthesized under high temperature and pressure

International Nuclear Information System (INIS)

Wu Qinghua; Liu Zhongyuan; Hu Qianku; Li Hui; He Julong; Yu Dongli; Li Dongchun; Tian Yongjun

2006-01-01

The thermal expansion has been investigated for a highly crystalline hexagonal BC 2 N compound synthesized by the compression of a turbostratic B-C-N precursor with iron catalyst at the high temperature of 1500 deg. C and the high pressure of 5.5 GPa. The thermal expansion in the c direction is large and linear with an expansion coefficient of 35.86 x 10 -6 K -1 up to 1000 deg. C, while in the basal plane, the a dimension displays a slight linear contraction up to 750 deg. C with a contraction coefficient of -8.76 x 10 -7 K -1 , but above 750 deg. C a linear expansion is observed with a larger expansion coefficient of 1.52 x 10 -6 K -1

Study of sorption and diffusion of 137Cs in compacted bentonite saturated with saline water at 60degC

International Nuclear Information System (INIS)

Suzuki, Satoru; Haginuma, Masashi; Suzuki, Kazunori

2007-01-01

The effect of compaction of bentonite on the sorption behavior of 137 Cs was studied for the safety assessment of the high level radioactive waste. The diffusion coefficients (effective D e and apparent D a ) and the distribution coefficient for sorption K d for 137 Cs in compacted and dispersed bentonite saturated with saline water were investigated at 60degC by four different sorption and diffusion experiments: the in-diffusion, through-diffusion, reservoir-depletion and batch sorption experiments. The system of the through-diffusion experiment was carefully designed to maintain the boundary conditions of constant concentration at each end of the specimen. D e and D a were found to be reproducible and showed good consistency among three of the diffusion experiments (through-diffusion, in-diffusion and reservoir depletion). K d of 137 Cs in compacted bentonite determined from the three types of diffusion experiments was in good accordance with that determined by the batch sorption experiment for dispersed bentonite. (author)

Quality changes in irradiated and nonirradiated boiled-dried anchovies after inter-country transportation and storage at 25degC

International Nuclear Information System (INIS)

Kwon, J.H.; Byun, M.W.; Warrier, S.B.; Kamat, A.S.; Alur, M.D.; Nair, P.M.

1993-01-01

Samples of nonirradiated and irradiated (5 kGy) dried anchovies (Engraulis encrasicholus) were transported from Korea to India for evaluation of microbiological, physico-chemical and organoleptic parameters during storage. The nonirradiated anchovies showed mould growth and an increase in total bacterial count by three log cycles over the initial load, after four months of storage at 25degC. However, 5 kGy irradiated samples packed with a laminated nylon/polyethylene (NY/PE) film exhibited 10 2 bacterial cells per g even after 6 months storage. Hunter's colour value, total volatile basic nitrogen, browning and lipid oxidation showed a good correlation with the organoleptic quality of stored anchovies. Partial changes in irradiated anchovies did not influence organoleptic acceptability. Differences in the levels of total volatile basic nitrogen and total volatile acid values in irradiated and nonirradiated samples may prove useful in distinguishing irradiated Korean anchovies from nonirradiated samples. (author). 24 refs., 2 tabs., 1 fig

Arterial Pressure Gradients during Upright Posture and 30 deg Head Down Tilt

Science.gov (United States)

Sanchez, E. R; William, J. M.; Ueno, T.; Ballard, R. E.; Hargens, A. R.; Holton, Emily M. (Technical Monitor)

1997-01-01

Gravity alters local blood pressure within the body so that arterial pressures in the head and foot are lower and higher, respectively, than that at heart level. Furthermore, vascular responses to local alterations of arterial pressure are probably important to maintain orthostatic tolerance upon return to the Earth after space flight. However, it has been difficult to evaluate the body's arterial pressure gradient due to the lack of noninvasive technology. This study was therefore designed to investigate whether finger arterial pressure (FAP), measured noninvasively, follows a normal hydrostatic pressure gradient above and below heart level during upright posture and 30 deg head down tilt (HDT). Seven healthy subjects gave informed consent and were 19 to 52 years old with a height range of 158 to 181 cm. A Finapres device measured arterial pressure at different levels of the body by moving the hand from 36 cm below heart level (BH) to 72 cm above heart level (AH) in upright posture and from 36 cm BH to 48 cm AH during HDT in increments of 12 cm. Mean FAP creased by 85 mmHg transitioning from BH to AH in upright posture, and the pressure gradient calculated from hydrostatic pressure difference (rho(gh)) was 84 mmHg. In HDT, mean FAP decreased by 65 mmHg from BH to AH, and the calculated pressure gradient was also 65 mmHg. There was no significant difference between the measured FAP gradient and the calculated pressure gradient, although a significant (p = 0.023) offset was seen for absolute arterial pressure in upright posture. These results indicate that arterial pressure at various levels can be obtained from the blood pressure at heart level by calculating rho(gh) + an offset. The offset equals the difference between heart level and the site of measurement. In summary, we conclude that local blood pressure gradients can be measured by noninvasive studies of FAP.

Il disavanzo pubblico degli stati Uniti, il Dollaro e l'Europa. (U.S. deficits, the dollar and Europe

Directory of Open Access Journals (Sweden)

O. BLANCHARD

2013-12-01

Full Text Available L'articolo valuta alcune delle controversie relative al ruolo dei deficit nel recupero , il rapporto tra deficit e tassi di interesse , i costi ei benefici di un dollaro forte degli Stati Uniti , e, infine, la fattibilità e opportunità di miglioramento, di assicurare o accelerare il recupero dell'Europa attraverso mosse di politica attiva . This paper reviews and assesses some of the controversies related to the role of deficits in the recovery, the relation between deficits and interest rates, costs and benefits of a strong US dollar, and finally the feasibility and desirability of enhancing, assuring or accelerating Europe’s recovery through active policy moves. The authors first provide an assessment of the current situation before focusing on the characteristics of a fiscal policy-led recovery. They then turn to the appreciation of the dollar before looking at the policy options open to Europe, arguing that a temporary and modulated fiscal expansion still appears both desirable and feasible.JEL: H62, E43, E62

DHA supplementation for late onset Stargardt disease: NAT-3 study

Directory of Open Access Journals (Sweden)

Giuseppe Querques

2010-06-01

Full Text Available Giuseppe Querques1, Pascale Benlian1, Bernard Chanu2, Nicolas Leveziel1, Gabriel Coscas1, Gisele Soubrane1, Eric H Souied11Department of Ophthalmology, University of Paris XII, Centre Hospitalier Intercommunal de Creteil, 2Department of Nutrition, University of Paris XII, Hopital Henry Mondor, Creteil, FranceBackground: We analyzed the effects of a docosahexaenoic acid (DHA supplementation in patients affected with late onset Stargardt disease (STGD.Methods: DHA (840 mg/day was given to 20 STGD patients for six months. A complete ophthalmologic examination, including best-corrected visual acuity (BCVA and multifocal electroretinogram (mfERG, was performed at inclusion day 0 (D0 and at month 6 (M6.Results: Overall, no statistical differences have been observed at M6 vs D0 as regards BCVA and mfERG (P > 0.05. Mild Improvement of BCVA and improvement of mfERG was noted in seven/40 eyes of four/20 patients. In the first patient, the peak of the a wave increased from 66 nV/deg² to 75.4 nV/deg² in the right eye (RE and 24.5 nV/deg² to 49.1 nV/deg² in the left eye (LE. The peak of the b wave improved from 122 nV/deg² to 157 nV/deg² in the RE, and 102 nV/deg² to 149 nV/deg² in the LE. In the second patient peaks of the a and b waves respectively increased from 11.8 nV/deg² to 72.1 nV/deg² and 53 nV/deg² to 185 nV/deg² in the RE. In the third patient the peak of the a wave increased from 37 nV/deg² to 43 nV/deg² in the RE, and from 31 nV/deg² to 45 nV/deg² in the LE; the peak of the b wave improved from 70 nV/deg² to 89 nV/deg² in the RE, and from 101 nV/deg² to 108 nV/deg² in the LE. In the fourth patient, the peak of the a wave increased from 39 nV/deg² to 42 nV/deg² in the RE, and from 40 nV/deg² to 43 nV/deg² in the LE; the peak of the b wave improved from 86 nV/deg² to 94 nV/deg² in the RE, and from 87 nV/deg² to 107 nV/deg² in the LE.Conclusion: DHA seems to influence some functional parameters in patients affected with

Effects of corrosion and precipitates on mechanical properties in the ferritic/martensitic steel cladding under ultra-long cycle fast reactor environment at 650 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Yong; Lee, Jeong Hyeon; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of); Shin, Sang Hun [KAERI, Daejeon (Korea, Republic of)

2016-05-15

This changes chemical compositions of inter-surface and effects on behavior of precipitations. NaCrO{sub 2} which is ternary sodium compound occurs intergranular corrosion resulting in thickness reduction. This change can cause a degradation of mechanical strength of structure material of UCFR. Therefore, we should consider longterm compatibility with sodium and study about life prediction. The research about ferritic/martensitic steel on effects of long term exposure in liquid sodium at 650 .deg. C, 20ppm oxygen includes weight loss of test material (Gr. 92) by corrosion and mechanism about nucleation and growth of precipitates like Laves-phase in bulk. There are many changes such as segregation of component to nucleate precipitates, affecting into microstructural evolution of the steel. Therefore, the thermochemical reaction research to predict behavior about precipitates should be performed. In a specific procedure, the micro-structure and the surface phenomenon of ferritic/martensitic steels (Gr. 92) that are exposed to liquid sodium at 650 .deg. C, 20 ppm oxygen and aged in high pure Argon gas environment to express bulk have been investigated by using scanning electron microscope (SEM) and transmission electron microscope (TEM). At 10 ppm oxygen designed oxygen value for UCFR, there is 107μm thickness reduction for 30 years. Thus, if there is no degradation of mechanical strength caused by aging effect, the tolerance of load of initial cladding should be higher than real load at least 23.6 %. Compared to specimens exposed to Ar-gas environment, Specimen which solutions are leaded into sodium has degradation of strength by reduction of solution hardening.

75 FR 38021 - Safety Zones; Annual Firework Displays Within the Captain of the Port, Puget Sound Area of...

Science.gov (United States)

2010-07-01

...[deg] 43.917' N 122[deg] 39.133' W 300 Langlie's Old Fashioned Independence Indianola 47[deg] 44.817' N... Kirkland , Lake 47[deg]40.583[min] N 122[deg]12.84[min] W 250 Washington. Three Tree Point Community Fireworks.. Three Tree Point......... 47[deg]27.033[min] N 122[deg]23.15[min] W 200 City of Renton Fireworks...

Buckling and reaction rate experiments in plutonium/uranium metal fuelled, graphite moderated lattices at temperatures up to 400 deg. C. Part I: Experimental techniques and results

Energy Technology Data Exchange (ETDEWEB)

Carter, D H; Clarke, W G; Gibson, M; Hobday, R; Hunt, C; Marshall, J; Puckett, B J; Symons, C R; Wass, T [General Reactor Physics Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1964-07-15

This report presents experimental measurements of bucklings, flux fine structure and fission rate distributions in graphite moderated lattices fuelled with plutonium/uranium metal at temperatures up to 400 deg. C in the sub-critical assemblies SCORPIO I and SCORPIO II. The experimental techniques employed are described in some detail. The accuracy of the experimental measurements appears to be adequate for testing methods of calculation being developed for the calculation of reactivity and temperature coefficient of reactivity for power reactors containing plutonium and uranium. (author) 26 refs, 17 tabs, 17 figs

Crystallization of rare earth germanates in the K2O-Ln2O3-GeO2-H2O at 280 deg C

International Nuclear Information System (INIS)

Panasenko, E.B.; Begunova, R.G.; Sklokina, N.F.

1980-01-01

Crystallization of rare earth germanates in potassium hydroxide solutions is studied at 280 deg C. Stability limits for different crystalline phases are established. Diorthogermanates Ln 2 O 3 x2GeO 3 (three structural modifications) are formed with all lanthanides except lanthanum. Germanates-apatites 7Ln 2 O 3 x9GeO 2 are characteristic for ''large'' lanthanides La-Nd. Alkali germanate of the composition 0.5 K 2 OxLn 2 O 3 xGeO 2 xnH 2 O is realized with the elements of the end of rare earth series, i.e., Tm-Lu. Some properties of the germanates synthesized are considered [ru

Transparent national strategies for long-term decarbonization in compliance with the 2 deg. C goal: The Deep Decarbonization Pathways Project

International Nuclear Information System (INIS)

Colombier, Michel; Waisman, Henri

2015-01-01

Fifteen countries among the biggest emitters of greenhouse gases are involved in the Deep Decarbonization Pathways Project (DDPP), which is based on 'country teams' of climate experts. This international project seeks to draw the pathways for a transition toward national decarbonization in compliance with the goal of limiting global warming to 2 deg. C maximum by 2050. These pathways should serve to: a) foresee the economic, technical and behavioral 'ruptures' to be addressed in order to facilitate the transition; b) identify specifically national factors in pathways toward decarbonization; and c) analyze the effects over time of this transition and the sequencing of the measures that might cause them. A preliminary report was released in September 2014, and the final report is scheduled for mid-2015. In support of an international agreement during the Paris Climate Conference, it will focus on the implications of deep decarbonization and the conditions for achieving it